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The New Science of Strong Materials or Why You Don't Fall Through the Floor
Abstract
This new edition of J. E. Gordon's classic introduction to the properties of materials used in engineering answers some fundamental and fascinating questions about how the material world around us functions. In particular, Gordon focuses on so-called strong materials, such as metals, wood, ceramics, glass, and bone. For each material in question, Gordon explains the unique physical and chemical basis for its inherent structural qualities in irrepressibly fresh and simple terms. He also shows how an in-depth understanding of these materials' intrinsic strengths (and weaknesses) guides our engineering choices, allowing us to build the structures that support our modern society. Philip Ball's new introduction describes Gordon's career and the impact of his innovations in materials research, while also discussing how the field has evolved since Gordon wrote this enduring example of first-rate scientific communication.
... dislocations. An 'edge' dislocation consists of a half-plane of atoms inserted between two planes of atoms, whilst a 'screw' dislocation consists of two faces of atoms being displaced relative to one another [19,[21][22][23]. Figure adapted from [24] under CC BY. ...
... While the elastic deformation can be explained in terms of interatomic forces, the plastic deformation of an MMC is mediated primarily by dislocations within the matrix [19,22]. Dislocations are a class of 'line' defects in a crystal, which cause misarrangements of atoms in a crystal lattice [19,[21][22][23], and are naturally present in most real crystals [19]. The two types of dislocations, edge and screw dislocations, are presented in Fig. 5. ...
... The Burgers vector b is usually an integer lattice vector [32], and hence can only take certain values in each crystal. As the atoms at a dislocation are already 'misaligned', it takes far less stress to cause planes of atoms to slip with respect to one another, as compared to the shearing well-aligned planes of atoms [19,21] (Fig. 6). This irreversible movement of atoms due to dislocations helps reshape the material to redistribute stresses [19,[21][22][23]. ...
Particle Reinforced Metal Matrix Composites (MMCs) are a special class of materials that are characterized by the incorporation of insoluble particles, often ceramics, into a metal matrix, which is either an alloy or a pure metal. These particles lead to a marked improvement in the characteristics of the alloy, particularly in their mechanical strength and resistance to fatigue. Moreover, their low costs of production and highly customizable properties have led to their extensive use in a range of industrial applications. Recently, academic interest has increased in investigating the use of smaller, nanoscale reinforcement particle sizes to synthesise MMCs over traditional micron reinforcements. Due to a wide range of effects which occur mostly at the microstructural level, the macroscopic properties of the MMCs are left greatly modified, with nanocomposites generally outperforming their microcomposite counterparts. This study gives a brief introduction to plasticity in MMCs for readers unfamiliar with materials science, then takes a closer look at the underlying physics and models proposed in previous studies to explain how modifying the size of the reinforcing particles in a metal matrix culminates in a composite with markedly distinct properties. We further assess the altered traits of these composites in light of industry demands.
... A variety of numerical approaches have been used to simulate fracture growth processes between several interacting and coalescing fractures (e.g. Bi, Zhou, and Qian 2016;Hazzard et al., 2000;Lunn et al., 2008;Madden et al., 2017;J. A.;McBeck et al., 2016;Zhou X. P. et al., 2015;Zhou and Wang, 2016). Simulations of fracture growth have demonstrated that the mode of fracture growth is dependent on the length and orientation of pre-existing cracks, stress state, and interactions of fractures for a given experiment. Models of multiple crack interactions have explicitly in ...
... P. Zhou and Yang 2012). Large numbers of 'flaws' have been considered with DEM simulations of micro-crack coalescence that include fracture-like arrangements of bonds and particles, but these models do not explicitly consider fracture tips (e.g., Hazzard et al., 2000;J.;McBeck et al., 2021c;J.;McBeck ...
... Large numbers of 'flaws' have been considered with DEM simulations of micro-crack coalescence that include fracture-like arrangements of bonds and particles, but these models do not explicitly consider fracture tips (e.g., Hazzard et al., 2000;J.;McBeck et al., 2021c;J.;McBeck et al., 2021b). ...
Unraveling the details of fracture propagation leading to catastrophic rock failure is critical for understanding the precursors to earthquakes. Here we present numerical simulations of fracture growth using a work optimization criterion. These simulations apply work optimization to fracture propagation by finding the propagation orientation that minimizes the external work at each increment of fracture growth, repeating this process for each growing fracture tip in the model. We simulate published uniaxial compression experiments performed on a cylinder of marble with pre-cut fractures of varied lengths, orientations, and positions. This suite of experiments provides an ideal benchmark for the numerical simulations because of the relatively simple boundary conditions and the range of pre-cut fracture geometries that focus deformation. We compare the results of homogeneous, isotropic model material to results that incorporate hundreds of small randomly oriented and distributed microcracks representing internal weaknesses, such as grain boundaries. From these numerical models, we find that slip on and propagation of microcracks governs the non-linear stress-strain response observed before failure under axial compression. We use a suite of Monte Carlo realizations incorporating different initial seeding of microcracks to explore the range of fracture propagation paths that might result from inherent variation between rock samples. We find that while models that include microcracks begin to propagate fractures at smaller cumulative axial strains than an equivalent homogeneous isotropic model, ultimately, models including heterogeneity require more energy to reach failure than the homogeneous model. These results highlight the critical role of heterogeneity, such as microcracks, within the processes leading up to failure.
... Few technical hurdles must be overcome for cargo airships to compete with re-Journal of Transportation Technologies frigerated trucks, but size is important. As an historical analogy, the railways could not compete with the cost of horse-drawn wagons, until their locomotives could haul more than five wagon-loads of freight [4]. Once the technical hurdles were overcome, trains became the dominant mode for long-haul freight movements 1 . ...
... The combined total of fresh fruit and vegetable imports from growing areas in the southern USA and Mexico weigh 3.0 million t. Using optimized lightweight 4 Each litre of diesel fuel contains 720 grams of carbon and when burned produces 2640 grams of carbon dioxide. https://connectedfleet.michelin.com/blog/calculate-co2-emissions/#:~:text=One%20litre%20of%20di ...
Intermodal competition changes with changes in technology, economics, and environmental concerns. Trucks and airships are generally considered not to be competitors, but this depends on the distance of haul. The tonne-kilometer cost of trucking rises much more quickly with distance than it does the cost of a cargo airship. At some distance, the two modes are direct substitutes.
The costs of the Mexico-Canada refrigerated truck supply chain are compared with the costs of a 100t-lift, electrically-powered airship. The flight characteristics of the Hindenburg Zeppelin are used as a model for a modern cargo airship. The supply chain cost of trucking tomatoes is used to test the theorical proposition. The cost difference works out to about US10￠/kg (5￠/lb) advantage for trucking Mexican tomatoes to Canada. However, this cost disadvantage of the airship could be made up by their vibrationless ride, better air circulation and one-day service versus four days by truck.
This alternative form of transportation could have a positive impact on worldwide north-south distribution of food. Airships can overcome trade barriers and distance to open new markets for perishable food exports. In addition, they would reduce the carbon emissions of transport. Canada imports 160,000 refrigerated truckloads of fruits and vegetables by from the southern US and Mexico. With an average driving distance of 3,000 km, these trucks emit 606,000 MT of CO2 annually. Airships powered by hydrogen fuel cells would have zero-carbon emissions. Markets are not yet incorporating the environmental advantage of airships in any freight comparison, but inevitably this will be important.
... The change in electrospinning setup, collector configuration, precursors, solvent, and degree of humidity allows to produce a wide variety of polymer nanofiber including [172] random oriented, aligned, patterned, spider-web-like nanofiber/net structures and ribbon-like, bead-on-string, porous, helical, necklacelike, rice grain-shaped, firecracker-shaped, core-shell, hollow, multichannel tubular, multi-core cable-like, tube-in-tube, and nanowire-in-microtube structures (Fig. 7a-q) [173]. Mechanical properties, thermal stability, electrical conductivity, photocatalytic activity, and bioactivity of nanofiber can be tuned by the controlling fiber diameter [174,175]. The reduction of fiber diameter to nanometer scale has an important effect on system response time to electronic stimuli and the current carrying capability of the fiber over metal contacts. ...
... With global concerns about fossil fuels depleting, climate change, and environmental deterioration, the development of efficient and clean energy conversion and storage devices has been significantly accelerated. There is essential need to improve the performance of some devices, including harvest efficiency, durability, conversion efficiency, and power density [174]. Electrospinning can produce fiber mats with high specific surface and high porosity, as well as some other excellent properties. ...
... De l'ubiquité de l'âme e-Phaïstos, XI-1 | 2023 (Gordon, 1968(Gordon, , 2006 symbolise le mieux les dysfonctions accumulées par l'analyse tout au long du XVII e siècle, et pour presque un siècle encore, autour de la nature et du lieu des efforts tranchants au sein d'un vulgaire bout de bois en flexion. (1638) part du principe que la poutre de bois cède selon une contrainte uniforme qui affecte toute sa section (figure 6a). ...
... De l'ubiquité de l'âme e-Phaïstos, XI-1 | 2023 (Gordon, 1968(Gordon, , 2006 symbolise le mieux les dysfonctions accumulées par l'analyse tout au long du XVII e siècle, et pour presque un siècle encore, autour de la nature et du lieu des efforts tranchants au sein d'un vulgaire bout de bois en flexion. (1638) part du principe que la poutre de bois cède selon une contrainte uniforme qui affecte toute sa section (figure 6a). ...
... Why should this angle be 54.7°? In a cylinder that is pressurized from the inside and that is in a state of equilibrium, the circumferential stresses are always twice as high as the axial stresses [32], i.e., we can determine a theoretical angle α' by abstracting the mesh in the cylinder, in a first step, to a two-dimensional right-angled triangle (= simplified force parallel diagram) ( Figure 7A) with an edge length 2a (corresponding to the assumed vector of the circumferential stress) and a vertical edge length a (corresponding to the assumed vector of the axial stress) ( Figure 7B). For this simplified two-dimensional mesh with twice as much stress in one direction as in another (perpendicular) direction, we obtain an angle of α' = tan −1 (2) = 63.43°. ...
... Why should this angle be 54.7 • ? In a cylinder that is pressurized from the inside and that is in a state of equilibrium, the circumferential stresses are always twice as high as the axial stresses [32], i.e., we can determine a theoretical angle α' by abstracting the mesh in the cylinder, in a first step, to a two-dimensional right-angled triangle (=simplified force parallel diagram) ( Figure 7A) with an edge length 2a (corresponding to the assumed vector of the circumferential stress) and a vertical edge length a (corresponding to the assumed vector of the axial stress) ( Figure 7B). For this simplified two-dimensional mesh with twice as much stress in one direction as in another (perpendicular) direction, we obtain an angle of α' = tan −1 (2) = 63.43 • . ...
Since most plant movements take place through an interplay of elastic deformation and strengthening tissues, they are thus ideal concept generators for biomimetic hingeless actuators. In the framework of a biomimetic biology push process, we present the transfer of the functional movement principles of hollow tubular geometries that are surrounded by a net-like structure. Our plant models are the recent genera Ochroma (balsa) and Carica (papaya) as well as the fossil seed fern Lyginopteris oldhamia, which hold a net of macroscopic fiber structures enveloping the whole trunk. Asymmetries in these fiber nets, which are specifically caused by asymmetric growth of the secondary wood, enable the up-righting of inclined Ochroma and Carica stems. In a tubular net-like structure, the fiber angles play a crucial role in stress–strain relationships. When braided tubes are subjected to internal pressure, they become shorter and thicker if the fiber angle is greater than 54.7°. However, if the fiber angle is less than 54.7°, they become longer and thinner. In this article, we use straightforward functional demonstrators to show how insights into functional principles from living nature can be transferred into plant-inspired actuators with linear or asymmetric deformation.
... The principal of a composite architecture is another key issue for the specific mechanical performance of biological materials. The benefit of the joining of different materials is a gain in mechanical performance which can not be achieved by any of the single materials (Gordon, 1991;Wainwright et al., 1976). In nature, fibres, mineralized tissues or ceramics which are very stiff but brittle are combined with a relatively soft matrix to yield a stiff and considerably tough composite, for instance bone , nacre (Nassif et al., 2005) or the glass skeleton of the deep see sponge of the genus Euplectella (Aizenberg et al., 2005). ...
... For the gain in toughness, the interfaces play a crucial role. It is well known that in case of a crack, the highest amount of stress is always concentrated at the tip of the crack (Gordon, 1991). In brittle materials like glass or ceramics, only little amount of energy is needed to propagate a crack and because of the high stress concentration this will happen quickly (which virtually everybody has already experienced in daily life). ...
... Engineers have historically had to rely on pragmatism to design, build, and manage physical assets long before the development of detailed simulation or digital twins. (The historical willingness of (in particular British) engineers to bypass what they considered to be overly theoretic approaches to characterizing stress and strain is discussed in Professor James E. Gordon's popular books (Gordon, 1991a(Gordon, , 1991b.) Rather, domain knowledge has always been (suboptimally) integrated with data from experiments to prevent failures. ...
Novel methods of data collection and analysis can enhance traditional risk management practices that rely on expert engineering judgment and established safety records, specifically when key conditions are met: Analysis is linked to the decisions it is intended to support, standards and competencies remain up to date, and assurance and verification activities are performed. This article elaborates on these conditions. The reason engineers are required to perform calculations is to support decision-making. Since humans are famously weak natural statisticians, rather than ask stakeholders to implicitly assimilate data, and arrive at a decision, we can instead rely on subject matter experts to explicitly define risk management decision problems. The results of engineering calculation can then also communicate which interventions (if any) are considered to be risk-optimal. It is also proposed that the next generation of engineering standards should learn from the success of open source software development in community building. Interacting with open datasets and code can promote engagement, identification (and resolution) of errors, training and ultimately competence. Finally, the profession’s tradition of independent verification should also be applied to the complex models that will increasingly contribute to the safety of the built environment. Model assurance will be required to keep pace with model development to identify suitable use cases as adequately safe. These are considered to be increasingly important components in ensuring that methods of data-centric engineering can be safely and appropriately adopted in industry.
... Incidentally, engineering has a long history of borrowing from biology dating back to classic civilizations' use of ballistae, which used twisted tendons to accelerate projectiles on account of the little weight they would add to the machine [8]. In the same spirit, we suggest a megastructure design that not only allows components to fail, but has a self-repair mechanism to replace the broken components. ...
One of the biggest perceived challenges in building megastructures, such as the space elevator, is the unavailability of materials with sufficient tensile strength. The presumed necessity of very strong materials stems from a design paradigm which requires structures to operate at a small fraction of their maximum tensile strength (usually, 50% or less). This criterion limits the probability of failure by giving structures sufficient leeway in handling stochastic components, such as variability in material strength and/or external forces. While reasonable for typical engineering structures, low working stress ratios --- defined as operating stress as a fraction of ultimate tensile strength --- in the case of megastructures are both too stringent and unable to adequately control the failure probability. We draw inspiration from natural biological structures, such as bones, tendons and ligaments, which are made up of smaller substructures and exhibit self-repair, and suggest a design that requires structures to operate at significantly higher stress ratios, while maintaining reliability through a continuous repair mechanism. We outline a mathematical framework for analysing the reliability of structures with components exhibiting probabilistic rupture and repair that depend on their time-in-use (age). Further, we predict time-to-failure distributions for the overall structure. We then apply this framework to the space elevator and find that a high degree of reliability is achievable using currently existing materials, provided it operates at sufficiently high working stress ratios, sustained through an autonomous repair mechanism, implemented via, e.g., robots.
... The properties of a material depend on its structure, phase, mineralogical, and chemical composition, which vary according to its nature [1]. The structure of real materials is complex, as it typically consists of both homogeneous and heterogeneous regions [2]. The physicomechanical properties of materials are significantly influenced by interatomic bonds [3], physical characteristics (such as density, melting temperature, etc.) [4], structural defects [5], and other structural features [6]. ...
The research aimed to investigate the structure of glass-basalt composite pipes and explore the relationship between their Renyi statistical dimensions and physicomechanical properties. Physical experiments were conducted to measure and analyze the elasticity of glass-basalt composite pipes. The experiments included testing the modulus of elasticity and other mechanical properties. Fractal analysis was applied at the microstructural level to assess the influence of the fiber matrix structure on the physicomechanical behavior of the pipes. The study explored the possibility of modeling the microstructure of glass-basalt composite pipes using 3D fractal analysis. A correlation was established between the spectrum of multifractal dimensions (D-200, D0, D1, D2, D200), the heterogeneity of the fiber matrix f(α), and the elasticity properties (Young’s modulus). For the obtained fractal models predicting Young’s modulus, the correlation coefficients (R2) were 0.95 for D0, 0.92 for D1, 0.90 for D2, 0.82 for D-200, and 0.68 for f(α). These results can be applied for rapid estimation of Young’s modulus using optical microscopy and photomicrographs of the microstructure.
... A través de millones de años de evolución la naturaleza ha logrado optimizar sus recursos con el fin de maximizar el desempeño de las estructuras biológicas existentes sobre nuestro planeta [1]. Este hecho motivó, desde tiempos inmemoriales, la búsqueda de conceptos de diseño basados en las criaturas vivientes; por ejemplo, Leonardo da Vinci diseñó una máquina voladora a partir de numerosos estudios realizados sobre la anatomía de aves. ...
En este trabajo se presenta el desarrollo de una herramienta de simulación numérica que permite estudiar la aerodinámica inestacionaria y no-lineal asociada al complejo movimiento de batimiento de las alas de insectos y aves pequeñas. El fin último de este esfuerzo es utilizar los resultados provenientes de este estudio para diseñar micro-vehículos aéreos de alas batientes inspirados en la biología. La cinemática del “vuelo natural” involucra, simultáneamente, movimientos hacia abajo y hacia arriba, rotaciones, oscilaciones y cambios significativos en el ángulo de ataque efectivo del ala. El modelo aerodinámico adoptado en este esfuerzo es una versión modificada de la versión 3D del unsteady vortex lattice, una generalización del conocido vortex lattice method, ampliamente utilizado en flujos incompresibles y estacionarios. El modelo permite tener en cuenta el comportamiento no-estacionario; las no-linealidades aerodinámicas asociadas con grandes ángulos de ataque y grandes desplazamientos producto del movimiento del eje longitudinal de cada ala; las deformaciones estáticas; y flujos dominados por vorticidad. En este trabajo se analiza la influencia del cuerpo del insecto en la generación de sustentación, para diferentes configuraciones de vuelo suspendido (hover), con y sin la presencia de una corriente de aire. La cinemática utilizada para prescribir el movimiento de las alas fue la desarrollada por Dickinson para mover un robot dinámicamente escalado (Robofly). La combinación del modelo cinemático con el modelo aerodinámico, junto con un pre-procesador para generar en forma paramétrica la geometría del insecto (cuerpo y alas) conforman una herramienta computacional que permite, entre otras: utilizar diferentes cinemáticas para el movimiento de las alas, definir en forma interactiva distintas geometrías para el insecto, predecir el campo de movimiento del fluido alrededor de la estructura del cuerpo y de las alas batientes, estimar la distribución espacio-temporal de la vorticidad adherida al cuerpo/alas del insecto, estimar la distribución de vorticidad y forma de las estelas emitidas desde los bordes filosos de las alas, predecir las cargas aerodinámicas actuantes sobre éstas, y tener en cuenta todas las posibles interferencias aerodinámicas.
... T he aerospace industry has long been driven by a relentless pursuit of materials that offer the perfect balance of strength and low weight [1,2]. The materials used in aerospace applications play a fundamental role in determining the overall performance and safety of aircraft and spacecraft [3,4,5]. ...
The aerospace industry's unceasing quest for lightweight materials with exceptional mechanical properties has led to groundbreaking advancements in material technology. Historically, aluminum alloys and their composites have held the throne in aerospace applications owing to their remarkable strength-to-weight ratio. However, recent developments have cata-pulted magnesium and its alloys into the spotlight. Magnesium possesses two-thirds of aluminum's density, making it a tantalizing option for applications with regard to weight-sensitive aerospace components. To further enhance magnesium's mechanical properties, researchers have delved into the realm of metal matrix composites (MMCs), using reinforcements such as Alumina, Silicon carbide, Boron carbide and Titanium carbide. However, meager information is available as regards to use of Multi-Walled Carbon Nanotubes (MWCNTs) as a reinforcement in magnesium based MMCs although, CNTs exhibit excellent stiffness coupled with very low density. In the light of above, the present work focusses on development of lightweight magnesium based MMCs using CNTs as nano-fillers. This research explores the synthesis and characterization of MWCNT-reinforced AZ31 magnesium alloy composites. The weight fractions of MWCNTs were varied from 0.3% to 1.2% in steps of 0.3%. Powder metallurgy technique has been used to develop the composite. Ball milling was used to blend the composite mixture of AZ31 & CNTs. Microstructural studies such as optical micrograph, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) have been carried out on the developed composites. Micro hardness and compression strength tests have been carried out on the developed composite. X-ray diffraction (XRD) and Energy Dispersive Spectroscopy (EDS) studies have also been carried out to analyze the compositional elements present in the developed composite. Microstructural studies reveal a fairly uniform distribution of CNTs within the matrix alloy AZ31. A significant improvement in both hardness and compressive strength have been observed for the developed composites when compared with the base alloy.
... , signalling an emerging focus on combining biomimicry and PV integration to optimize the performance of these facades. Exploring adaptation principles from nature within the expanding realm of biological knowledge has the potential to inform novel design solutions that are adaptable, flexible and efficient [17]. In this study, the term used to describe bio-inspired facades or roofs designed to efficiently regulate or harvest solar radiation, or fulfil both functions, is "biomimetic adaptive solar building envelopes" (Bio-ASBEs). ...
Recognizing the significance of solar energy as a vital renewable energy source in building envelope design is becoming more and more important and needs urgent attention. Exploring solar adaptation strategies found in plants offers a wide range of effective design possibilities that can substantially improve building performance. Thus, integrating solar technologies with biomimetic solar adaptive solutions could establish a suitable combination towards a sustainable design. In this context, this study follows an interdisciplinary approach to provide a link between plants’ solar adaptation strategies, building integrated photovoltaics and building envelope design. To do so, a framework has been presented using data synthesis and classification to support the potential integration of three photovoltaic (PV) technologies with plant-inspired building envelope design, facilitating a harmonizing approach between biomimetic design and the application of photovoltaic technologies in buildings.
... The retardation of the main crack and delamination described by the Cook-Gordon mechanism occurs when the adhesive strength of the interface is lower than that of the layers. Gordon numerically estimated the conditions required for implementing a mechanism to describe a crack of any shape by correlating the maximum stresses along the direction of the crack with the maximum stresses directed perpendicular to its surface [12]. To achieve these conditions, it is necessary to obtain a given composition (doping level) for each layer as well as a high contrast in the properties at their boundaries. ...
This paper presents the results of experimental data analysis, which indicate an increased resistance of heterogeneous multilayer clad composites to dynamic loading destruction compared with homogeneous materials. The reason for this is the crack retardation caused by lamination at the boundary of the layers. The destruction of heterogeneous compact composite samples by cyclic off-center stretching also occurs with crack retardation, with the fractogram clearly demonstrating the transverse tightening of the sample section. We argue that crack nucleation plays a decisive role in the process of dynamic destruction of heterogeneous composites obtained by both multilayer cladding and explosion welding. This study presents generalized calculated data confirming the influence of the sign and magnitude of residual stresses (the appearance of a stress discontinuity) on the conditions of fatigue surface crack nucleation and propagation. Unlike homogeneous materials obtained by casting, forging (rolling), or cladding, which are characterized by a linear dependence of the crack propagation velocity on the dynamic stress intensity coefficient, for multilayer composites consisting of strong and viscous layers, a sharp crack deceleration is observed. This is due to the transition of the crack boundary between the strong and viscous layers. This paper presents studies of the corresponding properties of adjacent layers on the integral characteristics of the deposited composite.
... Nature has gone through evolution over the 3.8 Gyr since life is estimated to have appeared on the Earth (Gordon, 1976). Nature has evolved objects with high performance using commonly found materials. ...
In recent years, increasing environmental and health concerns about
the toxicity of lead combined with the strict legislation banning the use of
lead-based solders have created an inevitable driving force for the
development of lead-free solder alloys (Shen etal., 2005; Shen et al.,
2005; Wei et al., 2009; Shen et al., 2006; Torres et al., 2012; Flandorfer
et al., 2008; Çadırlı et al., 2011; Braga et al., 2007; Shalaby, 2013; Yang
et al., 2008; Awe and Oshakuade, 2014; Miric and Grusd, 1998; Morando
et al., 2014). The search for a global Pb-free replacement for Sn-Pb
eutectic alloy has been evolving as the threat of a regional lead ban
became a reality in July 2006. Over the twelve years from 1994 to 2006,
the manufacturing, performance, and reliability criteria for Pb-free solder
joints have become increasingly complex as relationships between the
solder alloy, the circuit board materials and construction, and the
component designs and materials have been revealed through widespread
experiments of the companies, industrial consortia, and university
researchers (Shen etal., 2005; Shen et al., 2005; Wei et al., 2009; Shen et
al., 2006; Torres et al., 2012; Flandorfer et al., 2008; Çadırlı et al., 2011;
139
Braga et al., 2007; Shalaby, 2013; Yang et al., 2008; Awe and
Oshakuade, 2014; Miric and Grusd, 1998; Morando et al., 2014;
Manasijević et al., 2007). Researching and replacing conventional tinlead
(Sn-Pb) solders with Pb-free materials required examination of the
basic properties of these alloy systems. These include physical, chemical,
mechanical, and electrical features, as well as cost and manufacturability.
Among these, the physical properties, such as surface tension, interfacial
tension, copper as the base metal, and contact angles, are important
because of their direct correlation with the wettability of the solder
(Manasijević et al., 2007). A material's electrical conductivity is very
important for developing electronic materials and interconnection
technologies, especially in modern industry and microelectronics (Shen et
al., 2006). In most cases, high-level mechanical properties are required
for industrial applications. The hardness and strength of the alloys mainly
depend on their microstructure; thus, numerous work has been
accomplished on micromechanics to dissection the practice of these
alloys (Braga et al., 2007; Manasijević et al., 2007; Zhang et al., 2014;
Hu et al., 2009; Zou et al., 2009; Mei and Morris, 1992; Morris et al.,
1993) The melting temperature of the Sn-Zn eutectic alloy, which is
lead-free, is about to the Sn-Pb' melting point. Nevertheless, new solder
alloys must provide economic, physical, and chemical properties and
fulfil other conditions. The melting points of lead-free solder alloys
developed in this respect should be close to the conventional Sn-Pb
eutectic alloy; their strength and stability should be similar or superior.
Also, in terms of production cost, the costs of newly developed alloys
must be capable of competing with lead-containing alloys (Billah et al.,
2011; Frear et al., 1994).
This work aims to explore the thermal, electrical, mechanical, and
microstructure of Sn- 57 wt.% Bi, Bi-39 wt.% Sn-3 wt.% Sb and Bi-58.5
wt.% Sn-12.2 wt.% Zn eutectic alloys.
... Under tension and compression, or along its axis, a structural glass fiber is both stiff and strong. A typical fiber is long and narrow, which causes it to buckle readily, however this is only because of the fiber's long aspect ratio, which makes it appear as though the fiber is weak under compression [25]. ...
Asante public sculptures epitomize the remarkable contributions of past and present Asantes who have impacted greatly on the sustainable development of urban spaces in the geographical regions occupied by the Asantes of Ghana. The public sculptures honor the heroes and heroines who have immensely contributed to the sustainable development of Asanteman while offering an aesthetically pleasing facelift to the urban spaces in the Kumasi Metropolis in the Ashanti Region of Ghana. This appraisal study that utilized iconographic and visual analytical frameworks scholarly discusses seven major Asante public sculptures with the aim of unraveling the socio-cultural context of Asante aesthetics and how these public sculptures speak to the history and culture of the Asante people. Moreover, it illuminates how public sculptures serve as historical monuments offering insightful historical and cultural education on significant events and personalities in the development of Asanteman while enhancing the public urban spaces in the Kumasi Metropolis.
... Under tension and compression, or along its axis, a structural glass fiber is both stiff and strong. A typical fiber is long and narrow, which causes it to buckle readily, however this is only because of the fiber's long aspect ratio, which makes it appear as though the fiber is weak under compression [25]. ...
The purpose of the study was to undertake an innovative project of producing a mobile sink basin from fibreglass as an intervention for hand washing in Ghana. The qualitative research approach with the arts-based descriptive research design guided the study. Fifty-five (55) study participants in the Kwame Nkrumah University of Science and Technology, Ghana were purposively sampled to evaluate the project in the context of handwashing in this era of pandemics. Data were primarily gathered via semi-structured interviews, observations and photographs. Detailed account on the tools and materials as well as the procedural steps for the production of the innovative fibreglass mobile sink by meticulously following the rules in arts-based descriptive research design. The qualitative data were analysed using the qualitative thematic analysis. The study found that the fibreglass mobile sink would be useful for handwashing and proper hand hygiene at homes, schools, healthcare facilities, workplaces, and marketplaces to prevent the spread of infectious diseases. In the face of the global COVID-19 pandemic and future pandemics, the study suggests the scaling up of this innovative mobile sink due to its convenience, cost-effectiveness, accessibility and portability that would encourage the Ghanaian citizenry to practice handwashing. The study recommends that the Ghana government via the Ministry of Health in Ghana should seek for funding avenues to support the mass production of this innovative project. Also, the Ministry of Health must collaborate with higher education institutions in organizing and funding projects of staff and students targeted at arresting the daunting health-related issues such as handwashing to curb the spread of infectious diseases.
... The idea of development of a joint resembling a knot has been for a long time of great interest to researchers probably since the times of the wellknown books of J. Gordon [21,22]. A large number of works are devoted to the optimization of reinforcement structures near holes using computer simulation [23][24][25][26][27][28][29][30][31]. ...
... The bio-inspired design has been adapted to construct novel materials that impact a variety of fields [7]. With millions of years of natural selection, creatures have evolved peculiar structures, forms, and functions to adapt to the environment and to outweigh competitors [8]. ...
Fouling causes serious problems in daily lives and mass industrial processes. Modern industry has made lots of artificial anti-fouling surfaces especially bio-inspired surfaces with some effective strategies to tackle the fouling issue. These surfaces inspired by natural creatures like lotus and sharks show both highefficiency and eco-friendly properties. This review discusses the model behind the anti-fouling properties, the mechanism of various types of fouling, and the strategy of both natural and bio-inspired surfaces. Also, the possibility of building a wide-range anti-fouling and durable surface is discussed.
... W ithin a Particle System, a spring is calculated following Hooke's Law of Elasticity. This states that a force can be determined by a springs degree of displacement from its rest length (rest length is the moment at which a spring exerts no force) (Gordon 2006). While this does not account for non-linear behavior, it does provide an approximate and relative description of forces as they move through a particular tensile topology. ...
... This work attempts to establish rapid craft protocols for a light-sensing infl atable skin system. By developing a working prototype which incorporates material and electrical behaviors and properties (Gordon 2006) through the use of a range of rapid prototyping and CNC tools (Silver 2006), this exploration demonstrates design's ability to integrate physical and digital media as scaled constructions and performance-driven architectures, beyond their traditional role as representation and simulation media. Moreover, beyond the demonstration of a working prototype, the description of design through fabrication may support such material sensibility in design. ...
... Thus, when studying it in the first semester of the second year, according to the work program, students must study all theoretical mechanics (see Figure 1), knowledge of which has been accumulated since ancient times (the term "mechanics" was introduced by the great ancient philosopher Aristotle/384-322 BC/) and throughout history has been constantly enriched, even in the Middle Ages, when the development of science was hampered by the church. Thus Galileo Galilei/1564-1642 /, being cursed by the church for his astronomical discoveries, resisted the materials, believing that it was the safest and least seditious object that could only then be imagined [17]. And add here such names as Archimedes, Robert Hooke, Isaac Newton, Leonardo da Vinci -none of them left technical mechanics without a huge scientific achievement. ...
... Nature has gone through evolution over the 3.8 Gyr since life is estimated to have appeared on the Earth (Gordon, 1976). Nature has evolved objects with high performance using commonly found materials. ...
Thermoforming technology, involves heating and forming of a sheet or film in to the desired shape. Mostly amorphous engineering thermoplastics (Acrylonitrile butadiene styrene-ABS, Polystyrene-PS, Polyvinyl chloride-PVC and Polyethylene terephthalate glycol-PETG) are used in thermoforming due to their wide forming temperature range.
Sometimes, semi-crystalline thermoplastics such as Polypropylene-PP and
Polyethylene-PE are used in thermoforming applications, although they are though to shape due to their narrow melting temperature range. Forming
process is called depending on the thickness and form of the material to be thermoformed. If the plastic material is flexible and fed as rolls, process is called Roll-fed thermoforming. If the material to be thermoformed is a sheet which is cut and prepared with predetermined dimensions, thermoforming process is called as Cut-sheet thermoforming. Also thermoforming machines are called according to plastic material feeding types (Ashter, 2014; Morris, 2017; Schwarzmann, 2019a; Selke et al., 2021; Tempelman et al., 2014; Throne, 2017). Initially, the sheet or film to be thermoformed is fixed in such a way
as to provide sealing. Clamping frame is employed to provide better
sealing between mould and thermoformed material. Plastic sheet is heated to a temperature which depends upon the type of thermoplastic material. The forming temperature is chosen below the melting temperature and
above the glass transition temperature. Heating can be performed using different methods. Contact heating, convection heating and Infrared radiation heating are some of these techniques(Schwarzmann, 2019b). Positive or negative air pressure is utilized to force the sheet to take the shape of the mould effectively. In some thermoforming operations plug assist may be required to provide better thickness distribution along the mould surface. If only vacuum is applied, the process is called vacuum forming. After plug is employed in thermoforming, process is called Plug Assisted Thermoforming (Hosseini et al., 2006). Studies over the past two decades have provided important information on the effect of variation of thermoforming process parameters on final product properties. Chen et al. 2008, investigated the effects of processing parameters such as mold temperature, film preheating temperature, plug
speed, plug holding time, and plug depth on the dimensional variation and
thickness distribution. They observed that an increase in the thermoforming depth will cause wrinkling and multiple-step
thermoforming may reduce the residual stress of the final thermoformed
product. Morales et al. 2014, investigated the effect of the thermoforming process parameters on the sheet friction coefficient. It has been found out that coefficient of friction increases with an increase in sheet temperature. They showed that it was not possible to detect a significant coefficient of friction variations depending upon the plug material. Several attempts have been made to show the importance of thermoforming process for other
industries. Even production of microelectronics and planar optical waveguides(Hoffmann et al., 2020; Shen et al., 2022; Zulfiqar et al., 2021). Also, some simulation studies have been reported on production and forming of different composites(Harhash et al., 2021; Nardi & Sinke, 2021; . Additionally, heating methods and simulation in thermoforming have been studied by many researchers using Computer Aided Engineering (CAE)
packages(Erchiqui, 2018; Schmidt et al., 2003). Some literature studies have focused alternative thermoforming materials and their deformation
behavior during thermoforming(Mohammadian-Gezaz et al., 2006; .
Thickness distribution is an increasingly important area in thermoformed part manufacturing. Because, thickness variation can simply
affect the outer appearance of the product. Especially for the thermoformed
packages; color, light transmittance, air and gas permeability is one of the most critical factors. Additionally, thickness distribution is one of the factors which influences the packages rigidity and strength.In this study, effect of variation of plug depth and diameter on thickness distribution of semi-finished thermoformed part, was
investigated comparatively. PVC sheets were utilized in thermoforming
operations. Initially, a plug which has a constant diameter (40 mm) were used in thermoforming operation by changing the plug depth in a conical female mould. Then, thermoforming operations were repeated using plugs
which have different diameters, for a constant plug depth. Thickness variations for each case were examined comparatively. Thickness change in sidewall and bottom of the thermoformed product was studied via graphical method.
... High-quality wood flour can be made from hardwoods attributable to their durability and strength. Commercial production of wood flour started in 1906, and the first commercial product from wood flour was a gear shift knob for a Rolls Royce automobile in 1916 (Gordon 1988). ...
The overall objective of this study was to explore the potential of utilizing secondary
processing mill residues generated in Maine (1.6 million tons annually) in Wood-Plastic
Composites (WPCs). Attributable to the huge shipping costs for transporting wood flour over long distances, wood pellets are explored as alternative feedstock for WPCs manufacturing. The mill residues from four species based on their abundance and potential applicability for utilization in WPCs manufacturing were used to make the two different feedstocks. The properties of the wood flour and pellets were studied along with the comparison of the properties of polypropylene-based WPCs using both of these feedstocks separately. In addition to this, the Network Analyst tool in ArcGIS and Sensitivity analysis were used for the transportation cost analysis on shipping these materials via truck transportation. Lastly, SimaPro software was used for life-cycle assessment (LCA) analysis to analyze the potential environmental impacts of wood
flour and pellet production utilizing the mill residues and then transporting them to WPC
manufacturers.
On average, the conversion of residues to wood flour and then wood flour into pellets
reduced the moisture content by 54% and 52% respectively and increased the bulk density by 119% and 276% respectively. The physical and mechanical properties of WPCs using wood flour or pellets separately mixed with polypropylene were similar for both controls and formulations using coupling agents. On average, the transportation costs of wood pellets via a truck were reduced by at least 25% compared to wood flour and up to 70% in other transportation mediums having a larger weight limit. Based on the LCA analysis of the case study, transportation had the highest impact on the environment in contrast to other input variables related to production. Likewise, for similar quantities, the production and shipping of wood pellets appears to be more environmentally friendly than wood flour. Effects of global warming potential (GWP) for one ton (characterization) and one truckload (normalization) was higher by 8% for wood flour as compared to the pellets.
It is expected that this study will ultimately encourage investors to establish an industry
segment supplying raw materials for WPC production in ME and ensure the efficient outlet of mill residues. Furthermore, WPC manufacturers would be benefit from the minimization of the raw material transportation costs through the utilization of an alternative wood feedstock that would positively impact their overall production process.
... By studying natural adaptions, from an ever-growing body of biological knowledge, innovators can extract functional characteristics and translate these characteristics into innovative, adaptive, flexible and more efficient designs. Life has been evolving on earth for over 3.8 billion years and has adapted to changing environmental circumstances (Gordon 1984). Life has, for example, derived high performance materials using common elements (Bhushan 2009). ...
Greenhouse gas (GHG) emissions leading to anthropogenic global warming continue to be a major issue for societies worldwide. A major opportunity to reduce emissions is to improve building construction, and in particular the effectiveness of building envelope, which leads to a decrease in operational energy consumption. Improving the performance of a building's thermal envelope can substantially reduce energy consumption from heating, ventilation, and air conditioning while maintaining occupant comfort. In previous work, a computational model of a biomimetic building façade design was found to be effective in temperate climates in an office context. Through a case study example based on animal fur and blood perfusion, this paper tests the hypothesis that biomimetic building facades have a broader application in different building typologies across a range of climate zones. Using bioinspiration for innovation opens new ideas and pathways for technological development that traditional engineering design does not provide. This study exemplifies the process in a building façade, integrating a new form of insulation, heating and cooling. Methods of mathematical modelling and digital simulation methods were used to test the energy reduction potential of the biomimetic façade was tested in a set of operational applications (office, school, and aged care) and across different climate zones (tropical, desert, temperate, and cool continental). Results indicated that the biomimetic façade has potential to reduce energy consumption for all building applications, with the greatest benefit shown in residential aged care (67.1% reduction). Similarly, the biomimetic building façade showed potential to reduce operational services energy consumption in all climate zones, with the greatest energy reductions achieved in the tropical (55.4% reduction) and humid continental climates (55.1% reduction). Through these results the hypothesis was confirmed suggesting that facades engineered to mimic biological functions and processes can improve substantially decrease building operational energy consumption and can be applied in different building classifications and different climate zones. These results would significantly decrease operational greenhouse gas emissions over the lifetime of a building and provide substantial savings in energy bills. Such facades can contribute to the further reduction in greenhouse gas emissions in a broad range of contexts in the built environment and other areas of technology and design. The flexibility and adaptability of biomimetic facades exemplify how biological strategies and characteristics can augment and improve performance in different environments, since the organisms that inspire innovation are already well-adapted to the conditions on earth. This study also exemplified a method by which other biomimetic building envelope features may be assessed. Further work is suggested to assess economic viability and constructability of the proposed facades.
Graphic abstract
... Highquality wood flour can be made from hardwoods attributable to their durability and strength. Commercial production of wood flour started in 1906, and the first commercial product from wood flour was a gear shift knob for a Rolls Royce automobile in 1916 [10]. Wood flour uses can be grouped into absorbent, chemically reactive substances, chemically inert fillers, modifiers of physical properties, mildly abrasive materials, and decorative materials. ...
The generation of secondary processing mill residues from wood processing facilities is extensive in the United States. Wood flour can be manufactured utilizing these residues and an important application of wood flour is as a filler in the wood–plastic composites (WPCs). Scientific research on wood flour production from mill residues is limited. One of the greatest costs involved in the supply chain of WPCs manufacturing is the transportation cost. Wood flour, constrained by low bulk densities, is commonly transported by truck trailers without attaining allowable weight limits. Because of this, shipping costs often exceed the material costs, consequently increasing raw material costs for WPC manufacturers and the price of finished products. A bulk density study of wood flour (190–220 kg/m3) and wood pellets (700–750 kg/m3) shows that a tractor-trailer can carry more than three times the weight of pellets compared to flour. Thus, this study focuses on exploring the utilization of mill residues from four wood species in Maine to produce raw materials for manufacturing WPCs. Two types of raw materials for the manufacture of WPCs, i.e., wood flour and wood pellets, were produced and a study of their properties was performed. At the species level, red maple 40-mesh wood flour had the highest bulk density and lowest moisture content. Spruce-fir wood flour particles were the finest (dgw of 0.18 mm). For all species, the 18–40 wood flour mesh size possessed the highest aspect ratio. Similarly, on average, wood pellets manufactured from 40-mesh particles had a lower moisture content, higher bulk density, and better durability than the pellets from unsieved wood flour. Red maple pellets had the lowest moisture content (0.12%) and the highest bulk density (738 kg/m3). The results concluded that the processing of residues into wood flour and then into pellets reduced the moisture content by 76.8% and increased the bulk density by 747%. These material property parameters are an important attempt to provide information that can facilitate the more cost-efficient transport of wood residue feedstocks over longer distances.
... Their unique features have various applicability in industry, energy production and storage [9][10][11][12], environmental protection and improvement [7,8], photonic and electronic devices [32], and biomedical application [4][5][6]. Nanofibers can be rigid, elastic, or flexible, and by controlling the fibers' diameter, the nanofibers' bioactivity, electrical conductivity, photocatalytic activity, thermal stability, and mechanical properties can be tuned [33][34][35][36][37]. ...
In the present study, TiO2/WO3/C/N composite nanofibers were successfully prepared in a one-step process by electrospinning using a water-soluble precursor followed by annealing in argon. Titanium(IV) bis(ammonium lactato)dihydroxide (TiBALDH), and ammonium metatungstate (AMT) were used as the precursor for TiO2 and WO3, respectively. Different volume ratios of the precursors were added to a solution of PVP before electrospinning. The fibers were studied by thermogravimetry/differential thermal analysis (TG/DTA), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy coupled with energy-dispersive X-ray (SEM-EDX), transmission electron microscopy (TEM), Attenuated total reflection Fourier-transform infrared spectroscopy (ATR-FTIR), X-ray diffraction (XRD), Raman spectroscopy and UV–Vis diffuse reflectance spectroscopy (DRS). The photocatalytic activity of the fibers in visible light was investigated using methylene blue as a probe molecule. The fibers contained anatase TiO2 and monoclinic WO3. The diameter of the annealed fibers was for the 0% TiBALDH sample 830-1050 nm, while in contrast, for the 100% TiBALDH sample, it was 560-690 nm. The 90% TiBALDH sample (Kapp= 0.002min-1) had the highest photocatalytic activity, i.e., 40% of the dye degraded after 240 min.
... As the photomicrographs of Rodriguez-Navavarro et al. (2002;Figure 3-35) and Macleod, Bain, and Hancock (2006) show, there are sharp-angled crevasses between adjacent knobs where they join with each other. Therefore, according to Gordon (1976), stress energy in the presence of sharpangled junctions, as occurs when a shell receives an insult, concentrates at such junctions and increases to levels many times greater than the initial stress that caused the insult. Bain et al. (2006a) concluded microcracks originate from the intermammillary crevices which support this suggestion. ...
Egg shell breakage is and remains a source of economic loss to the egg producer. In general, about 3% of the eggs laid by hens housed in battery cages or in free-run systems have cracked shells. This number increases about another 1% for hens kept in enriched cages or housed free-range and a further 1 to 2% for those in aviaries. The range of cracked shells reported was from 2 to 12%, but there were few published reports for most production systems. The occurrence of dirty-shelled eggs is about 2 to 3% higher than the incidence of eggs with cracked shells. Shell breakage is also influenced by manufacturer of enrich cage systems. The highest impact eggs receive as they move from the hen to the retail store is in the laying house; overall, eggs receive impacts that average about 13 G. The material used to make egg cartons (paper pulp or plastic foam), the cases in which the cartons are shipped (cardboard or wire), and the location of a carton within the shipping case (top, middle or bottom) affect the occurrence of shell breakage when eggs are transported. Even apparently weak impacts to egg shells may cause microcracks to develop and if the impacts are stronger visible cracks become apparent or they may rupture the mammillary membranes which will allow the egg’s content to escape.
... The idea of development of a joint resembling a knot has been for a long time of great interest to researchers probably since the times of the wellknown books of J. Gordon [21,22]. A large number of works are devoted to the optimization of reinforcement structures near holes using computer simulation [23][24][25][26][27][28][29][30][31]. ...
Unidirectional composites exhibit the highest strength when stretched along the fibers. However, the proper determination of the strength faces great methodological difficulties. The main problems of tensile testing of polymer composites consisted in developing of the specimen shape and the method of specimen fixation which ensure the minimum impact of the stress concentration near the grips on the strength measurements. A conventional shape of the specimen with fillets is unsuitable for unidirectional polymers due to the splitting occurred in the fillet zones upon loading. Therefore, the specimens are usually standardized in the form of rectangular strips fixed using pads or special grips which provide constant transverse forces. However, with such a specimen shape, a significant stress concentration inevitably occurs at the edge of grips and the lower the ratio of the interlayer shear modulus to the longitudinal Young’s modulus, the greater the stress concentration impact. For the purpose of the most correct determination of the strength we propose to use specimens with smoothly varying dimensions at the same cross-sectional area which ensures keeping the total number of unbroken fibers in each section. The specimen thickness decreases when moving from the working part of the specimen to the gripping part, whereas the width (while maintaining the section area) grows to prevent the specimen collapsing resulting from transverse forces in standard self-tightening grips. Analytical and FEM modeling is performed to select a rational contour shape. Technological equipment has been developed and a procedure of manufacturing testing specimens has been worked out. The tensile test of specially manufactured curvilinear reinforced specimens showed higher strength values compared to standard rectangular strips or specimens with semicircular fillets.
... According to the analysis of hardening mechanisms of different polymer materials following compounds were chosen as hybrid matrix viscoelastic components: anaerobic polymer material 2. The destruction mechanism of hybrid matrix polymer composite materials containing viscoelastic components Viscoelastic components contained in fibrous fillers based PCM's hybrid matrix represent the inner reduced durability interface. To implement on the interface the Cook-Gordon crack blunting mechanism (figure 1) [6][7][8] the durability of interface should be less than 1/5 of the overall material's linkage strength. The amount of 1/5 is taken regarding that with any shape of crack and its way to spread, the ratio of the maximum parallel tension range to the maximum perpendicular (to the crack's surface) tension range is constant and equal approximately 1/5 [6]. ...
This article contains the description of different polymer composite materials (PCM) with different types of hybrid matrices. One of the components of PCM’s hybrid matrix is hardened as the other one stays in its viscoelastic condition. The following materials are chosen to serve as viscoelastic components of hybrid matrix: technical wax compound, anaerobic and organosilicone polymer materials. The use of viscoelastic materials allows the enhancement of PCM’s stress-strain properties. This article also contains: the destruction mechanism of polymer composite materials with different types of hybrid matrices; the quality control process of products made of polymer composite materials with different types of hybrid matrices; the localization method of hybrid matrix viscoelastic components by using infrared thermography during product molding process. The results of quality control are shown as thermograms.
... The natural world has had, by most accounts, some 3.8 Gyr of diverse development and evolution in order to refine such processes, and the materials subsequently produced [4,5]. It would seem natural to take inspiration from these materials and processes when creating nanomaterials or devices in the lab, perhaps efficiently resulting in novel technologies and approaches; however, it is clear that this path is often not quite as straightforward [2]. ...
The term ‘biomimetic’ might be applied to any material or process that in some way reproduces, mimics, or is otherwise inspired by nature. Also variously termed bionic, bioinspired, biological design, or even green design, the idea of adapting or taking inspiration from a natural solution to solve a modern engineering problem has been of scientific interest since it was first proposed in the 1960s. Since then, the concept that natural materials and nature can provide inspiration for incredible breakthroughs and developments in terms of new technologies and entirely new approaches to solving technological problems has become widely accepted. This is very much evident in the fields of materials science, surface science, and coatings. In this review, we survey recent developments (primarily those within the last decade) in biomimetic approaches to antifouling, self-cleaning, or anti-biofilm technologies. We find that this field continues to mature, and emerging novel, biomimetic technologies are present at multiple stages in the development pipeline, with some becoming commercially available. However, we also note that the rate of commercialization of these technologies appears slow compared to the significant research output within the field.
... The polymer matrix can be either thermoplastic polymer or thermosetting polymer. The first WPC produced was a composite made of phenol-formaldehyde resin and wood flour for use as gearshift knob in automobile [138]. Wood generally degrades at 220°C and thus it is important that the polymer used does not thermally degrade the wood component during thermomechanical processes. ...
Presently, environmental problems and regulations have caused awareness to producer liability concerning plastics recycling as they try to meet global demand. Process-induced degradation during recycling as well as degradation brought on by thermomechanical operations (e.g. extrusion, injection molding, etc.) or other processes typically leads to irreversible changes in the physicochemical properties and structure of the material. Thus, it is important to understand the magnitude and mechanisms of property deterioration during the recycling process via either chemical, thermomechanical, reutilization, or incineration methods while, looking into possible utilizations, applications, and solutions for the existing global accumulated PO waste. This review provides a comprehensive overview of the recent research efforts and industrial trends in PO recycling. Although a wide variety of POs exist in the market, this review focuses on polyethylene (PE) and polypropylene (PP). The ongoing challenges and future potential of plastic recycling are also discussed.
Inspired by the geometric structure of the bamboo culm sheath and the surface topology of the dung beetle, a bionic blade for a paddy field impeller was developed to enhance soil cultivation efficiency in rice plantations. The blade surface was modified by using laser-texturing with a macro-scale design to reduce soil resistance. Computational Fluid Dynamics simulations revealed a 47.10% increase in fluid velocity and a 46.87% reduction in drag force compared to conventional curved blades. In soil bin tests, the bionic blade demonstrated a 10.26% reduction in driving torque and an 11.32% increase in rotational speed due to decreased soil cutting resistance. Further investigation of the rotor's 190 mm and 210 mm sinkage depths highlighted the design’s effectiveness. The improved performance is attributed to reduced blade contact area and lower soil resistance in wet conditions. Surface treatments, including gas carburizing, case hardening, tempering, and epoxy cathodic electrodeposition coating, significantly enhanced the mechanical properties of the bionic blade, improving hardness, tensile strength, and corrosion resistance. This integration of bionic design and surface engineering offers a significant performance improvement for paddy field impellers, contributing to advancements in agricultural machinery for rice cultivation.
Some aspects of the relationship between two engineering disciplines, materials science and structural mechanics, are considered. Core structures are discussed from representative cells and volumes of composites reinforced with long and short fibers to spatial structures with a regular structure. This article considers various approaches to prediction and es-timations of the minimum mass of core systems at the initial stages of design. The main attention is paid to the study of the possibility of applying the dimensionless criterion of force perfection of a structure to the evaluation of the effi-ciency of materials with a heterogeneous structure. For this purpose, a computational experiment is set and described in detail, during which, on the basis of the simplest cubic Bravais lattice, truss structures of increasing complexity are gen-erated sequentially and their properties are analyzed using structural mechanics methods. It is shown that truss model-ing has a certain potential for predicting a number of mechanical characteristics of heterogeneous materials.
The polyester resin has been synthesized using maleic anhydride, phthalic anhydride and propylene glycol. Synthesized resin, styrene and jute fibre along with a catalyst were used for the composite preparation. The mechanical and thermal properties of composites were evaluated. The obtained composites were characterized by TGA (Thermal Gravimetric Analysis) and DTA (Differential Thermal Analysis).
The variety of wood-based products is huge; some are produced and marketed in large volumes while others are for a very specific use and therefore also often only produced in small volumes. This chapter introduces a group of new materials, existing mainly only in laboratories or in production at pilot scale. These materials often go under the name bioinspired materials and smart wood-based materials. The second part of the chapter presents engineered wood products (EWPs) with other or additional functions than only the load-bearing capacity related not only to properties such as acoustic, heat transfer, light-weight, and extraordinary shape stability, but also to functions such as hybrid functions, improved possibility to form to a given shape, installation solutions, and esthetic and tactile performance. These materials are already on the market since many years and are in this chapter briefly introduced.KeywordsBioinspired materialsSmart wood-based materialsHybrid wood elementsThermal-insulationSki coresBilayer constructionEngineered wood products
Nature contains technologies that will make our lives easier. Hundreds of examples of biomimetics are now found in our daily life, one of such is biosensors. Biosensors studies have been continuously developing in recent years. The increase and widespread use of these studies are due to the fact that biosensors give correct results in many application areas in a short time. Nanoparticle-based biosensors are preferred in environmental monitoring because they are very sensitive and fast. There are high levels of potential analyte in air, water, and soil. In addition to current pollution situations, they are potential uses for farming, horticulture, and mining nanobiosensors. Nanobiosensors can detect oil spills and radioactive contamination in groundwater, as well as the concentration of toxic wastes, carcinogens, and microorganisms that get into drinking water. This chapter presents information on the use of biomimetically developed nanobiosensors in the environment.
KeywordsBiomimeticEnvironmental monitoringNanoparticle
Os materiais criados pela natureza possuem propriedades únicas, resultado de sucessivas iterações ao longo dos anos, sendo, portanto, uma rica fonte de inspiração para o desenvolvimento de novas soluções em materiais. Neste estudo, foram avaliadas diferentes estruturas inspiradas no conceito brick-and-mortar, que compõe a microestrutura da madrepérola. Para isso, blocos sólidos foram conectados por estruturas circulares, com o intuito de alcançar o mesmo efeito de dissipação de energia que as placas de aragonita e o material orgânico propiciam. Para essa avaliação, utilizou-se de um software FEA (finite elements analysis) para a simulação de ensaios de compressão em amostras com diferentes geometrias de blocos internos, e analisada a absorção total de energia, bem como a energia absorvida específica de cada amostra. Os resultados demonstram que a estrutura sólida foi capaz de absorver 87 J/kg, enquanto as demais amostras com estruturas de ligação absorveram, em média, 91% menos energia. Analisando a distribuição de tensão nas amostras, estima-se que essa diferença ocorra devido à concentração de tensões excessivas nos elementos de ligação, causando falhas prematuras em regiões críticas das estruturas.
Este trabalho trata das inovações do design e investiga um modelo de inovação que se proponha à refletir sobre a prática da sustentabilidade no móvel doméstico. Coloca como objeto de estudo o home office, que é ambientado em um novo contexto econômico e social.
In general, material selection for an application depends on its mechanical properties such as the young’s modulus, shear modulus and bulk modulus. There is no material science without material characterization. The conventional mechanical testing involves breaking of the test piece while determining the mechanical properties, thus rendering the sample piece useless after testing. Moreover, conventional testing machines are bulky and costly. Non–destructive testing techniques were most commonly used for the detection and characterization of flaws. But in the past few decades many researchers are conducting experiments to even calculate material properties using NDT methods. In the present work an attempt has been made to use a NDT technique, namely Ultrasonic testing, to determine the mechanical properties of three Glass fiber reinforced polymer (GFRP) plates (Unidirectional, Bidirectional & cross directional).
Polymer and composite materials (PCMs) are widely used in various industries for production of small but complex parts and large-sized body parts subjected to significant loads. The production of more critical parts from PCM has led to the need to develop new compositions, structures and technologies for molding composites. The manufacturing technology of PCMs with a hybrid matrix is presented, one of the components of which retains its "liquid" state after the molding of the products, and the second is completely solid. In the resulting composite, the “liquid” components form an independent phase and together with the main binder material, the PCMs represent a hybrid matrix. The results of dynamic mechanical analysis (DMA) of basalt plastics with hybrid matrices, in which the composition of the “liquid” component are anaerobic technical wax and organosilicon polymer materials, are presented. DMA is performed on samples of two types: № 1 - samples with a low content of "liquid" components in the matrix and № 2 - samples with a high content of "liquid" components in the matrix. According to the results of the tests carried out, the best characteristics among PCMs with various types of hybrid matrices are possessed by samples with an organosilicon polymer material in the matrix
Optical fibre sensors (OFS) are increasingly used for structural health monitoring
(SHM) on aerospace-grade carbon fibre reinforced polymer (CFRP) components
owing to their lightweight, small diameter, multiplexing capabilities, and immunity
to electromagnetic interference. A network of permanently installed fibre Bragg
gratings (FBGs) would allow a transition from time-based maintenance (TBM) to
condition-based maintenance (CBM). TBM works well for aluminium alloy
components but imposes frequent and long downtimes on the aircraft when applied
to CFRP components, due to the sensitivity of CFRP to barely visible impact damage
(BVID). CBM can overcome this by performing maintenance only when the health
of the component suggests so. The current state-of-the-art of BVID detection with
OFS remains however at low technology readiness levels (TRL) and the
demonstrations found in literature are often not tested for their compatibility with
aerospace conditions.
To increase the technology readiness level of optical fibre sensor-based BVID
detection on aerospace-grade CFRP subcomponents, the specific objectives of this
thesis are: 1) to investigate the feasibility of embedding OFS in relevant aerospacegrade
CFRP components, 2 ) to develop an aerospace-grade OFS installation
method, 3) to investigate advances in ultrasonic guided wave detection with FBGs,
4) to obtain detection thresholds and ranges for BVID detection in combination with
relevant on-ground conditions, and 5) to develop a Global Damage Indexing system
for quantifying the health of a component, based on the readings of a multitude of
sensors.
In this dissertation we worked in a building-block approach, from coupon to
subcomponent level, by considering 4 aerospace-grade CFRP material systems:
thermoset, liquid resin infused (LRI) dry fibre, thermoplastic and thermoset with
advanced shielding properties. We first evaluate the feasibility of embedding
Ormocer coated single mode fibre (SMF) and acrylate coated microstructured optical
fibre (MOF) in the thermoset and LRI materials and investigate their effect on the
mechanical properties of the host material. We also report on developing a surface
mounted OFS network and test its compatibility with in-flight conditions. Using
surface mounted FBGs on CFRP coupons, we then report for the first time on
relevant detection thresholds and working distance radii for detecting calibrated
BVIDs, when considering on-ground conditions. Further on, we validate these
findings on element level by considering components with representative geometrical details. In the last step, we report on the use of 60 surface mounted FBGs
on a stiffened flat panel structure for developing a global damage index (GDI) as
health quantification that can readily be used as input for CBM. Moreover, we also
report on the use of an FBG in an embedded MOF for advances in distinguishing
between ultrasonic guided wave (UGW) modes, and on counterintuitive
implications of different FBG gauge lengths for UGW detection. We aim that our
results contribute to the increase in TRL for OFS in aerospace BVID detection for
enabling CBM on CFRP subcomponents.
The impacts of cold stress (4℃ for 0 h, 12 h, 24 h, 36 h and 48 h, respectively) on the components, structural and physical properties of myofibrillar protein (MP) gel from Procambarus clarkii were investigated. The physicochemical analysis indicated the secondary and tertiary structure of MP were unfolding to different degrees after cold stress when compared to the control. The MP gel hardness reached a maximum when the cold stress reached 24 h. Furthermore, the quantitative proteomics results indicated that 20 up-regulated differentially abundant proteins (DAPs) were detected in 24 h when compared to control, specifically include myosin light chain 1 (MLC1) and skeletal muscle actin 6. Additionally, the combined analysis confirmed that MLC1 and skeletal muscle actin 6 might play key roles in hardening shrimp meat under cold stress. The results could provide a theoretical reference for the changes in crayfish muscle quality during cold chain transportation.
In this chapter, material balance and its importance in the field of food science/engineering have been discussed. To do this, first, material balance is explained in detail using mass, i.e., mass flows and not volumetric flows. It must be remembered that masses are additive, but volumes are not always additive. Then, we provide a brief explanation of what is a process and state that the chapter focuses on continuous material balance problems under steady-state conditions. The core of the chapter details a proposed strategy to solve simple and complex material balance problems. We developed a five-step procedure, which is explained and then applied in examples. The chapter concludes with 3 solved problems and then proposes 24 problems, each one with the corresponding answer.
Wood has played a major role throughout human history. Strong and versatile, the earliest humans used wood to make shelters, cook food, construct tools, build boats, and make weapons. Recently, scientists, politicians, and economists have renewed their interest in wood because of its unique properties, aesthetics, availability, abundance, and perhaps most important of all, its renewability. However, wood will not reach its highest use potential until we fully describe it, understand the mechanisms that control its performance properties, and, finally, are able to manipulate those properties to give us the desired performance we seek.
The Handbook of Wood Chemistry and Wood Composites analyzes the chemical composition and physical properties of wood cellulose and its response to natural processes of degradation. It describes safe and effective chemical modifications to strengthen wood against biological, chemical, and mechanical degradation without using toxic, leachable, or corrosive chemicals. Expert researchers provide insightful analyses of the types of chemical modifications applied to polymer cell walls in wood. They emphasize the mechanisms of reaction involved and resulting changes in performance properties including modifications that increase water repellency, fire retardancy, and resistance to ultraviolet light, heat, moisture, mold, and other biological organisms. The text also explores modifications that increase mechanical strength, such as lumen fill, monomer polymer penetration, and plasticization.
The Handbook of Wood Chemistry and Wood Composites concludes with the latest applications, such as adhesives, geotextiles, and sorbents, and future trends in the use of wood-based composites in terms of sustainable agriculture, biodegradability and recycling, and economics. Incorporating decades of teaching experience, the editor of this handbook is well-attuned to educational demands as well as industry standards and research trends.
The complex structure of wood, one of the most abundant biomaterials on Earth, has been optimized over 270 million years of tree evolution. This optimization has led to the highly efficient water and nutrient transport, mechanical stability and durability of wood. The unique material structure and pronounced anisotropy of wood endows it with an array of remarkable properties, yielding opportunities for the design of functional materials. In this Review, we provide a materials and structural perspective on how wood can be redesigned via structural engineering, chemical and/or thermal modification to alter its mechanical, fluidic, ionic, optical and thermal properties. These modifications enable a diverse range of applications, including the development of high-performance structural materials, energy storage and conversion, environmental remediation, nanoionics, nanofluidics, and light and thermal management. We also highlight advanced characterization and computational-simulation approaches for understanding the structure–property–function relationships of natural and modified wood, as well as informing bio-inspired synthetic designs. In addition, we provide our perspective on the future directions of wood research and the challenges and opportunities for industrialization. The porous hierarchical structure and anisotropy of wood make it a strong candidate for the design of materials with various functions, including load bearing, multiscale mass transport, and optical and thermal management. In this Review, the composition, structure, characterization methods, modification strategies, properties and applications of natural and modified wood are discussed.
Due to excellent physical, chemical, and biological properties, such as excellent thermal, electrical, scalable, low cost, biocompatibility, biodegradability, and low cytotoxicity, nanocellulose and nanohydrogel are considered to be promising classes of polymers for a wide variety of engineering applications. These materials are widely used in energy storage, medical implants, biosensing, tissue engineering, drug delivery, environmental modification and monitoring, wound healing, and so on. In this chapter, we summarize recent literature on the design and preparation of novel nanocellulose and nanohydrogel-based materials, which are used for energy, environmental, and biomedical applications, including the challenges that still need to be addressed.
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