Schematic representation of diamagnetic, paramagnetic, and ferromagnetic materials microscopic structures at rest and in the presence of a magnetic field H.
In the last decades, LOC technologies have represented a real breakthrough in the field of in vitro biochemical and biological analyses. However, the integration of really complex functions in a limited space results extremely challenging and proper working princi‐ ples should be identified. In this sense, magnetic fields revealed to be extremely p...
Context in source publication
... on this parameter, it is possible to classify magnetic materials in three main categories: diamagnetic, paramagnetic, and ferromagnetic (Figure 2) . Diamagnetic mate-rials, such as bismuth or brass, have no net atomic or molecular magnetic moment and do not retain magnetization when the external magnetic field is removed. ...
The voltage noise characteristic and sensitivity of magnetic tunnel junction sensors are crucial for ultralow field detection. In this work, we used a soft magnetic material electrode Co70.5Fe4.5Si15B10 as a sensing layer to improve the sensitivity. Then, a bias field along the easy axis of a free layer was applied to improve the linearity and mani...
... Magnetic micro-devices have been developed in recent times for manipulation and capture of MNPs used for bio applications [9,10]. They are based on micro(electro)magnets, soft magnetic microstructures or external magnetic field generators. ...
... Such materials contain charged microparticles that can be influenced by an external magnetic field but as soon as it disappears the material reverts to its regular condition. When diamagnetic particles are subjected to a magnetic field they are repelled back because a magnetic field is induced in them in the opposite direction (Fig. 11) . Compressive testing of PrM samples was carried out in a situation that AMF was not present and most of charged particles had reverted to their original position but testing of PoM specimens were conducted in the presence of AMF. ...
Due to the importance of inventing new techniques capable of enhancing concrete structural properties while reducing environmental issues associated with CO2 emissions in concrete industry, which preoccupies environmental scientists, a novel investigation was performed on feasibility of benefitting from Alternating Magnetic Field (AMF) and silica particles to attain this goal. Hence, some experiments were conducted on cylindrical concrete specimens comprising different silica sand contents of up to 10%, wherein the influence of exposing fresh and hardened concrete to AMF of frequency 50Hz and density 0.5 Tesla (T) on compressive strength of 7 and 28-day specimens was evaluated. For this, a specialized test setup was assembled such that the specimen could be subjected to compressive force and AMF, simultaneously. It was found that AMF can improve concrete compressive strength, where this technique is more efficient as to exposing hardened concrete. What was significant about the results was the fact that adding silica sand not only improved concrete mechanical strength but also considerably enhanced the effectiveness of AMF in increasing concrete compressive strength, when applied to hardened concrete. For instance, replacing 10% of cement content with silica sand increased compressive strength of 28-day specimens by 8.4, but adding 10% silica sand along with exposing specimens to AMF yielded an increase of nearly 21% in real-time. Thus, developing this method can result in a new generation of smart constructions. Moreover, by adding 10% silica sand, the emission of carbon dioxide, a greenhouse gas, reduces by 10 percent while significantly enhancing compressive strength.
... NPs are an innovative option, allowing noncontact manipulation of physical, chemical, and biological samples.  Despite some reviews that can be found on the application of magnetic NPs in the biomedical area, recent progress on magnetic NPs, from synthesis to surface functional strategies and applications, demands for a comprehensive work that includes, summarizes, and discusses current directions and ongoing advances in this interesting and fast-growing research field. In this way, the first part of this review deals with the structure, synthesis, and properties of magnetic NPs, as well as their incorporation into nanocomposite systems. ...
Magnetic nanoparticles (NPs) are emerging as an important class of biomedical functional nanomaterials in areas such as hyperthermia, drug release, tissue engineering, theranostic, and lab-on-a-chip, due to their exclusive chemical and physical properties. Although some works can be found reviewing the main application of magnetic NPs in the area of biomedical engineering, recent and intense progress on magnetic nanoparticle research, from synthesis to surface functionalization strategies, demands for a work that includes, summarizes, and debates current directions and ongoing advancements in this research field. Thus, the present work addresses the structure, synthesis, properties, and the incorporation of magnetic NPs in nanocomposites, highlighting the most relevant effects of the synthesis on the magnetic and structural properties of the magnetic NPs and how these effects limit their utilization in the biomedical area. Furthermore, this review next focuses on the application of magnetic NPs on the biomedical field. Finally, a discussion of the main challenges and an outlook of the future developments in the use of magnetic NPs for advanced biomedical applications are critically provided.
Cette thèse s'intéresse à la localisation d'objets subcentimétriques en mouvement. L'intérêt croissant pour ce sujet provient de l'émergence du champ de la microrobotique mobile. En effet, de nombreux robots miniatures à actionnement sans contact sont envisagés pour des applications médicales in vivo. De plus, des techniques microrobotiques sont également à l'étude pour des opérations in vitro variées à l'échelle d'une cellule biologique unique. Toutefois, l'exécution précise de ces opérations implique de garantir le positionnement des entités manipulées. L'accès à une information de position est donc essentiel pour ces applications de la microrobotique dans le domaine biomédical.Pour répondre à ce besoin, cette thèse propose des méthodes de localisation innovantes basées sur des mesures d’impédance électrique. La méthode de la tomographie d'impédance électrique a été utilisée pour reconstruire une cartographie de la totalité d'un espace de travail. Des microrobots magnétiques se déplaçant dans cet espace ont pu être identifiés sur cette cartographie et suivis au cours de leurs mouvements. En milieu microfluidique, dans un système comportant moins d'électrodes, donnant donc accès à moins de mesures d'impédance, des microparticules se déplaçant à haute vitesse ont également pu être localisées au cours du temps. Sans cartographier la totalité de l'espace de travail, une méthode d'observation d'état (le filtre de Kalman étendu) a permis de combiner un modèle connu du déplacement des particules avec les mesures d'impédance réalisées pour estimer leur position.Ainsi, cette thèse montre par différents procédés que l’exploitation des variations d’impédance induites par la présence d’un objet subcentimétrique entre plusieurs électrodes peut permettre de déterminer la position de celui-ci.
Transport properties are extremely versatile and informative to investigate the fundamental processes in a large number of research areas. They are vital in many daily life applications and forefront technologies, as they provide diversified multifunctional behaviors in driving agents and response signals, for example, electrical, thermal, magnetic, optical, or their combinations, and couplings, both scalar and vectorial. This chapter illustrates the relevance of transport phenomena in research and in solid-state energy conversion [magnetocaloric, thermoelectric (TE)]. The extreme sensitivity of transport properties is also emphasized to reveal fundamental processes near first- and second-order phase transitions (fluctuations and universal behavior), of magnetic (ferro, antiferro) or structural (order–disorder) types. Transport in bulk solids remains almost unchanged from macro to microscale sizes, when the typical carrier mean free paths exceed interatomic distances. But it changes drastically at nanoscale size, when the carrier wavefunction is quantum confined. Illustrative examples will be discussed for the cases of ϱ(T) near an order–order spin-reorientation transition and for the behavior of S(T) and ϱ(T) near an order–disorder magnetic transition. The carrier collisions also allow direct energy conversion at the atomic level inside a solid as in the magnetocaloric effect in magnetic media. The underlying microscopic processes are examined to some extent. One also focuses on TE materials and devices, analyzing their general principles and properties, as well as their management and tailoring to achieve optimal device performance. Particular attention is also given to thermal conductivity optimization via material nanostructuring to increase the TE figure-of-merit.
Nowadays the Application of magnetic fields in all scientific fields such as: Engineering, Medicine, etc., has been widely developed and has led to most of the discoveries and inventions in the world in the last two centuries. In recent years, many studies have been conducted on the effect of magnetic fields on micro-structural properties of materials and the results have been employed widely in industry. Due to the importance of inventing new techniques towards enhancing concrete structures properties, a novel investigation was performed on feasibility of benefitting from Fixed Magnetic Field (FMF), Carbon Nanotube (CNT) and silica Sand particles to attain this goal. Hence, some experiments were conducted on cylindrical and Beam concrete specimens comprising different silica sand contents of up to 10% and CNT contents of up to 0.04%, wherein the influence of exposing fresh and hardened concrete to FMF of frequency 50Hz and density 0.5 Tesla (T) on compressive strength of 7 and 28-day specimens was evaluated. Therefore, some experiments were conducted on some concrete cylindrical and beam specimens, where the effect of applying FMF to fresh and hardened concrete on the compressive strength of 7 and 28-day and flexural strength 28-day specimens was investigated. On the other, it was found that FMF can improve compressive and flexural strength, but it is more efficient when applied to hardened concrete. What was most important was the significant role of silica content in increasing the effectiveness of FMF to enhance concrete compressive and flexural strength, when applied to hardened concrete. Since FMF can take concrete compressive strength on demand, in real time, this method can result in a new generation of smart constructions. It was found that exposing either fresh or hardened concrete to FMF improves compressive and flexural strength, where with increase in CNT content FMF is more efficient. Magnetizing specimens comprising 0.02% CNTs yielded a higher strength than that of non-magnetized specimens containing 0.04% CNTs. What was most significant was real-time concrete compressive strength enhancement during magnetizing hardened specimens, which affects many aspects of concrete elements as per ACI building code. This technique can be considered as a clue to developing a new generation of smart concrete structures capable of controlling their behavior while drastically reducing CNT content.
Majority of research on lab-on-chip devices was on single layer devices. Stacking a combination of microfluidic layers to silicon architecture gives substantial advantage to integrate precise sensors, actuators, and control systems. Advantages of multilayer stack are: (i) multiple functions can be incorporated into single chip and (ii) simultaneous analysis of both macroscopic and microscopic properties, for example, characterizing blood as a bulk fluid and at the individual component level at the same time. Such integrated systems enable the applications that lead to development of comprehensive diagnostics system. Challenges for developing such devices are integrating multiple layers – a combination of biocompatible microfluidics and silicon architectures; individual automated systems that incorporate sensors, actuators, and control systems; development of rapid data analysis and management; and development of diagnostic metrics to manipulate the actuators based on the responses (feedback control). This chapter reviews existing literature and techniques to address the above challenges through the prospect of a state-of-the-art silicon integrated lab-on-chip device with advanced automation coupled with novel data analysis tools to address critical applications in healthcare.
Cell manipulation tasks, especially in lab-on-a-chip applications for personalized medicine, could greatly benefit from mobile untethered microdevices able to wirelessly navigate in fluidic environments by means of magnetic fields. In this paper, the design, fabrication and testing of a magnetic platform enabling the controlled locomotion and immersion of microrobots placed at the air/liquid interface is proposed and exploited for cell manipulation. The proposed microrobot consists of a polymeric magnetic thin film that acts as cell transporter and a specific coating strategy, devised to enhance a safe cancer cell adhesion to the magnetic film. Experimental results demonstrated an overall cell viability and a fine control of magnetic microrobot locomotion. The proposed technologies are promising in view of future cell manipulation tasks for personalized medicine applications.
The necessity of on-site, fast, sensitive, and cheap complex laboratory analysis, associated with the advances in the microfabrication technologies and the microfluidics, made it possible for the creation of the innovative device lab-on-a-chip (LOC), by which we would be able to scale a single or multiple laboratory processes down to a chip format. The present book is dedicated to the LOC devices from two points of view: LOC fabrication and LOC application.