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Fundamentals of Physics, Extended 7th Edition
Abstract
No other book on the market today can match the 30-year success of
Halliday, Resnick and Walker's Fundamentals of Physics! Fundamentals of
Physics, 7th Edition and the Extended Version, 7th Edition offer a solid
understanding of fundamental physics concepts, helping readers apply
this conceptual understanding to quantitative problem solving, in a
breezy, easy-to-understand style. A unique combination of authoritative
content and stimulating applications. * Numerous improvements in the
text, based on feedback from the many users of the sixth edition (both
instructors and students) * Several thousand end-of-chapter problems
have been rewritten to streamline both the presentations and answers *
'Chapter Puzzlers' open each chapter with an intriguing application or
question that is explained or answered in the chapter * Problem-solving
tactics are provided to help beginning Physics students solve problems
and avoid common error * The first section in every chapter introduces
the subject of the chapter by asking and answering, "What is Physics?"
as the question pertains to the chapter * Numerous supplements available
to aid teachers and students The extended edition provides coverage of
developments in Physics in the last 100 years, including: Einstein and
Relativity, Bohr and others and Quantum Theory, and the more recent
theoretical developments like String Theory.
... Perangkat kapasitor plat sejajar memiliki konfigurasi dua plat konduktor yang saling sejajar, serta dipisahkan oleh dielektrik [15]. Kemampuan sebuah perangkat kapasitor dalam menyimpan muatan listrik dinyatakan dalam ukuran kapasitansi [16]. Pada perangkat kapasitor plat sejajar, besar nilai kapasitansi bergantung pada konstanta dielektrik vakum 0 , konstanta dielektrik relatif bahan , luasan dari konduktor plat sejajar dan jarak antar lempengan konduktor plat sejajar . ...
... Berdasarkan persamaan (7), besar perubahan muatan tiap satuan waktu ( ) pada perangkat kapasitor dapat dihitung sesuai dengan persamaan (16). ...
... Berdasarkan persamaan perubahan muatan tiap satuan waktu ( ) perangkat kapasitor pada persamaan (16), besar perubahan tegangan kapasitor tiap satuan waktu ( ) saat proses pengisian muatan dapat dihitung sesuai dengan persamaan (18). (18) Berdasarkan persamaan (18), hubungan teoritis profil tegangan kapasitor tiap satuan waktu secara teoritis saat proses pengisian (charging) dapat dilihat pada Gambar 2. Pada proses pengisian, tegangan kapasitor meningkat secara eksponensial seiring proses pengisian berlangsung. ...
Pada dasarnya kain tenun terdiri atas struktur anyaman benang-benang yang terbuat dari bahan serat tekstil melalui suatu proses pertenunan. Salah satu jenis serat yang telah lama dikenal sebagai bahan baku pembuatan kain tenun adalah serat kapas. Terdapat tujuh jenis konstruksi kerapatan benang kain tenun kapas 100% yang telah digunakan sebagai material dielektrik pada penelitian ini. Pada penelitian ini telah dilakukan pengamatan mengenai pengaruh konstruksi kerapatan benang kain tenun kapas 100% (kain kanvas) terhadap konstanta dielektrik dan profil tegangan pengisian & pengosongan pada perangkat kapasitor plat sejajar. Pengamatan konstanta dielektrik dan perilaku tegangan perangkat kapasitor plat sejajar berdielektrik kain tenun kapas 100% saat proses pengisian & pengosongan telah dilakukan dengan menggunakan perangkat mikrokontroler Arduino Uno. Proses pengisian & pengosongan kapasitor telah dilakukan dengan menggunakan skema rangkaian seri resistor-kapasitor (RC). Hasil pengamatan menunjukkan kesesuaian cukup baik antara hasil prediksi dan eksperimen pada perilaku profil tegangan kapasitor plat sejajar berdielektrik kain tenun kapas 100% saat proses pengisian & pengosongan dengan nilai R2 > 0,9. Telah ditemukan hubungan antara parameter kerapatan benang kain tenun kapas 100% terhadap konstanta dielektrik dan profil tegangan pengisian & pengosongan perangkat kapasitor plat sejajar. Hasil menunjukan bahwa semakin besar nilai kerapatan benang kain tenun kapas 100%, maka semakin besar nilai konstanta dielektrik kain tersebut. Woven fabric consists of interlacing threads made from fiber material by weaving process. One type of fibers which is known as raw material for making woven fabric is cotton fiber. In this research, there are seven types of yarn-fabric density of 100% cotton fabric that has been used as dielectric materials. In this study, the influence of woven dielectric yarn density on the dielectric properties and the voltage charging & discharging profiles of the parallel plate capacitor devices has been carried out. The observation of the dielectric properties and the voltage in the parallel plate capacitor devices during the charging and discharging process are carried out using an Arduino Uno microcontroller device. The charging and discharging profiles are measured by using a series of resistor-capacitor (RC) circuit. The results of the charging process and the discharging process obtained R2 > 0.9, which indicates that the correlation between the predicted and experimental results has a very good relationship. It has been found that the correlation between the woven dielectric yarn density on the dielectric constant and the charge-discharge profiles of the parallel plate capacitor. It also has been found that the higher density of the 100% cotton fabric, the higher the dielectric constant value of the fabric.
... = ( + ) [3] 11. = ( ) [3] The alternating voltage across the two stator assemblies establishes a current that is proportional to the impedance of the circuit connecting the two stator assemblies. The resulting current has the greatest amplitude during electrical resonance as it is dependent only on the alternating voltage across the stator and the value of the resistive load. ...
... = ( + ) [3] 11. = ( ) [3] The alternating voltage across the two stator assemblies establishes a current that is proportional to the impedance of the circuit connecting the two stator assemblies. The resulting current has the greatest amplitude during electrical resonance as it is dependent only on the alternating voltage across the stator and the value of the resistive load. ...
... 14. = = cos ( + ) [3] 15. ...
The electric field does work onto charges parallel to itself. With such, a rotating electric dipole is able to produce alternating voltage within neighboring capacitive structures. The amplitude of this voltage is independent of the rate of rotation of the dipole; but rather, dependent on the difference in voltage of the dipole moment. This alternating voltage produces an alternating current within a circuit connecting the capacitive structures. The electrical circuit may contain a resistive load, and an inductor which enables the current to resonate with the alternating voltage. The mechanical work against the rotation of the electric dipole is proportional to the electric energy stored within the capacitive structures. It will be shown that the electrical power dissipated within the resistive load is eight Pi times larger than the resistive mechanical power required to maintain rotation of the electric dipole.
... However, as the lungs and great vessels supporting the heart mitigate its over displacement, most of the vertical force of chest compression (a) would convert to a force vertical to the long axis of the heart to squeeze RV(b), while dissipating the remaining tangential vector. 21 While ejecting blood within RV to the pulmonary arteries, some of this force will be transmitted to the interventricular septum (c) to squeeze LV (d). This phenomenon results from the interventricular interdependence as both ventricles share the interventricular septum and pericardium. ...
... 3,4,6,12,13,20 Meanwhile, to maximise the stroke volume within the human circulatory system during CPR, the stroke volumes of RV and LV should equalise according to the principles of biophysics. 13,21,22 To generate the same stroke volume, RV may need less workload than LV considering its smaller after loads of pulmonary vascular resistance than the systemic vascular resistance for LV. 23,24 Nonetheless, targeting Point_ max.LV only will diminish stroke volume if CPR continues without adequate compression of RV, letting it function as a stagnation point. ...
... 13 Meanwhile, among the vertical compressing vectors applied to the sternum ( Figure 3A,a), only the vector vertical to the cardiac surface ( Figure 3A,b) would be effectively transmitted into the heart, whereas the remaining tangential vector would dissipate. 21 Considering these, Point_optimum may be located somewhat rightwards to Point_max.RV theoretically ( Figure 3A,① rather than ② or ③). ...
Background
Some researchers have reported thatapplying compressioncloser to the maximum diameter of the left ventricle (Point_max.LV) isassociated with worse clinical outcomes, challenging its traditional position as optimum compression point (Point_optimum). By locatingthe mid‐sternum (the actual compression site)in terms of Point_max.LV and its right ventricular equivalent (Point_max.RV),we aimed to determine its optimumhorizontal position associated with increased chances of returnofspontaneouscirculation (ROSC).
Methods
A retrospective,cross‐sectional study was performed at a university hospital from 2014 to 2019 on non‐traumatic out‐of‐hospital cardiac arrest (OHCA)victims who underwent chest computed tomography. On absolute x‐axis, we designatedthe x‐coordinate of the mid‐sternum (x_mid‐sternum) as 0 and leftward direction as positive. Re‐definingthe x‐coordinateof Point_max.RV and Point_max.LV as 0 and 1 interventricular unit (IVU), respectively, wecould convert x_mid‐sternumto‘−x_max.RV/(x_max.LV − x_max.RV) (IVU)’.Using multiple logistic regression analysis, we investigated whether this converted x_mid‐sternum was associated with clinical outcomes, adjusting core elements of the Utstein template.
Results
Among 887 non‐traumatic OHCAvictims, 124[64.4 ± 16.7 years, 43 women (34.7%)]were enrolled. Of these, 80 (64.5%) exhibitedROSC. X_mid‐sternum ranging from − 1.71 to 0.58(−0.36 ± 0.38) IVU was categorised into quintiles: <−0.60, −0.60–−0.37, −0.37–−0.22, −0.22–−0.07 and ≥−0.07 (reference) IVU. The first quintile was positively associated with ROSC(odds ratio [95% confidence interval], 9.43 [1.44, 63.3]).
Conclusion
Point_optimum mightbe located far rightwards to Point_max.RV, challenging the traditional assumption identifying Point_optimum as Point_max.LV.
... The buoyant force, or the socalled Archimedes principle, is directly proportional to the object's volume. Therefore, for small-size objects, this Archimedes principle is still negligible [1], [2]. ...
... George Gabriel Stokes derived a statement known as Stokes' Law for the frictional force of fluid against a spherical body moving in a viscous fluid. Meanwhile, some stated that the fluid friction force is proportional to the square of the velocity (v 2 ) [1] Crowe mentioned that fluid friction, specifically aerodynamic drag, which is an essential parameter in transportation, is defined as [5], [6]: ...
... Motion of a point-like massive projectile thrown in vacuum with initial velocity in a vertical plane under the sole action of gravity is a theme of interest in introductory physics and engineering college courses [2] [3]. Although simple it sets the foundation to building more realistic applicable cases. ...
... For microscale projectiles such as a bacteria linear velocity-dependent forces are used [4]. For larger scales e.g., a baseball, a parachute velocity-squared are considered [2]. Issues of interest in both cases include physical quantities such as time of flight and geometric quantities such as trajectories, range, maximum height etc. ...
... The current scales with the applied voltage (U ) and resistance (R) according to Ohm's law: [79] ...
... Values from Ref.[79]. ...
The signaling dynamics in neuronal networks includes processes ranging from lifelong neuromodulation to direct synaptic neurotransmission. In chemical synapses, the time delay it takes to pass a signal from one neuron to the next lasts for less than a millisecond. At the post-synaptic neuron, further signaling is either up- or down-regulated, dependent on the specific neurotransmitter and receptor. While this up- and down-regulation of signals usually runs perfectly well and enables complex performance, even a minor dysfunction of this signaling system can cause major complications, in the shape of neurological disorders. The field of organic bioelectronics has the ability to interface neurons with high spatiotemporal recording and stimulation techniques. Local chemical stimulation ,i.e.local release of neurotransmitters, enables the possibility of artificially altering the chemical environment in dysfunctional signaling pathways to regain or restore neural function. To successfully interface the biological nervous system with electronics, a range of demands must be met. Organic bioelectronic techniques and materials are capable of reaching the demands on the biological as well as the electronic side of the interface. These demands span from high performance biocompatible materials, to miniaturized and specific device architectures, and high dose control on demand within milliseconds.
... Although such problems are frequently dealt with theoretically in textbooks [3], they are seldom studied experimentally. The absence of an empirical approach may have a negative effect on learning processes because students may be led to think that the theoretical model has no connection with real life, without actually having tested their preconceptions against experimental evidence. ...
... To gain further insight, Fig. 5 shows the velocities of the same points, in the laboratory frame of reference (left) and in the frame of reference centred on the hub of the wheel (right), but this time when the wheel is rolling without slipping. Direct inspection of the left panel shows, as theory predicted, that the velocity of the point of contact with the floor is zero, while the velocity of the highest point is twice that of the centre of mass [3]. On the other hand, the right panel shows that the modulus of the velocity at the highest and lowest points are similar to each other and similar, also, to the modulus of the velocity of the centre of mass in the laboratory frame of reference. ...
The kinematics of a rigid body that undergoes a transition from slipping to rolling without slipping poses considerable difficulties for students. In the experiment described here, a bicycle wheel that was initially spinning freely was placed in contact with a rough surface and a digital film was made of its motion. Using Tracker software for video analysis, we obtained the angular velocity of the wheel and velocity vectors for several points on the wheel, in the frame of reference of the laboratory as well as in a relative frame of reference having as its origin the wheel's center of mass. The velocity of the wheel's point of contact with the floor was also determined, and the time period of transition between sliding and rolling was visually examined. A complete picture of the kinematic state of the wheel in both frames of reference was obtained, which was subsequently compared with a theoretical model. An empirical approach of this sort to problems in mechanics can contribute to overcoming the considerable difficulties they entail.
... The middle term (Δx/Δt) is just the particle's velocity υ; and (Δt/Δt 0 ) is the velocity-dependent clock-time ratio ( ) 2 1 1 c υ − or γ [2]. With these substitutions, the general definition for momentum, in vector form, is ...
... The middle term (Δx/Δt) is just the particle's velocity υ; and (Δt/Δt 0 ) is the velocity-dependent clock-time ratio ( ) 2 1 1 c υ − or γ [2]. With these substitutions, the general definition for momentum, in vector form, is ...
... The specimens with the addition of glass fibers (random and layers) revealed decreasing in density as shown in Fig.(2) & Fig.(3), this decreasing resulted from the light weight glass fibers which made the specimens lighter than the control specimens resulting in decreasing of density due to the direct proportionality between the weight and density. [14] ...
... The density was directly proportional to the weight according to the density rule which is the weight divided by the volume, the light weight glass fibers made the specimens lighter than control specimens and consequently reduced the density. [14] • Random glass fibers addition showed higher reduction in density of mortar (10.6%) than layers glass fibers (8.56%) compared with control specimens. • Random and layered glass-fiber addition with 7% SBR caused lower reduction in density than glass fibers addition without SBR. ...
In the field of construction materials the glass reinforced mortar and Styrene Butadiene mortar are modern composite materials. This study experimentally investigated the effect of addition of randomly dispersed glass fibers and layered glass fibers on density and compressive strength of mortar with and without the presence of Styrene Butadiene Rubber (SBR). Mixtures of 1:2 cement/sand ratio and 0.5 water/cement ratio were prepared for making mortar. The glass fibers were added by two manners, layers and random with weight percentages of (0.54, 0.76, 1.1 and 1.42). The specimens were divided into two series: glass-fiber reinforced mortar without SBR and glass-fiber reinforced mortar with 7% SBR of mixture water. All specimens were tested after curing for 7 and 28 days, glass-fiber reinforced mortar exhibited better properties than control mortar in improvement of compressive strength and lowering the density after curing for 28 days due to the completion of cement hydration reaction.. For compressive strength the best results were achieved with 1.42 wt.% layers glass-fiber reinforced mortar with 7% SBR which gave 41.56 MPa. On the other hand, the addition of 1.42 wt.% random glass-fiber without SBR addition caused the beast reduction in density by 10.6% and produced lighter structure than control sample.
Keywords: Random glass fibers , Glass fibers layers, SBR, compressive strength, density.
... This work step must be proficient in learning to apply conventional MR principles. (Halliday et al., 2014) Students who experience the MR learning process with the help of a computer can perform a faster and more in-depth analysis (Permadi, 2018;Permadi & Setyaningsih, 2018). Based on his learning experience, the graph in question 7 can be reproduced using the Excel program with synthetic data that can be made based on the curved mirror formula. ...
Learning physics through the investigation of phenomena using practicum equipment in the laboratory is the real core of learning physics. The basic competence of prospective science teachers towards understanding concepts through investigating phenomena is well developed. The achievement of other, more abstract concept representation competencies such as numerical, graphical, and mathematical representations requires new methods or ways in the learning process. The development of computer technology as part of further investigation of learning in the laboratory needs to be developed to facilitate learning. The purpose of this research is to investigate how to improve competence in understanding concepts based on verbal representations (Verb Rep) in the form of investigations of phenomena, to achieve multiple representations (MR) (Formal Representation, Numerical Representation, Graphical Representation, Pictorial Representation) with computer-based learning. The results showed that the conventional group (N=30; M=72.87; SD = 7.03; SE = 1.28) had a lower average score on the test results than the experimental group (N = 30; M = 83.27; SD = 4.93; SE = 0.89). Independent mean statistical tests showed significant differences (t (30) = -6.63; p <0.001; r = 0.78) between groups learning to use one representation (conventional) and those using MR to solve problem-solving cases of lens content and curved mirrors, with the category of effect size (r)0.78 exceeding 0.50 (large effect).
... The excitation frequency can be determined from the frequency analysis of the blade response when operating in the unsteady loading environment. There are one or more natural frequencies of all mechanical structures, and resonance can be reached when the excitation frequency reaches any of the structure's natural frequencies (44). The excitation frequencies are generally engine order (EO) multiples. ...
Rotor blades experience unsteady forces and aerodynamic losses when operating in a distorted inflow. The structural analysis of rotors under these conditions, therefore, is of prime importance during the early design phase. This work introduces a computationally efficient design framework that links the aerodynamic design and structural analysis of the rotor. Rotor structural analysis comprises computing dynamic stresses, the excitation frequencies, and resonance margins at various modes of vibration. A design space encapsulating fan stage design variables, aerodynamic performance, and rotor structural constraints is explored and optimized for maximum fan stage efficiency subject to aerodynamic and structural constraints.
... while 'k' is a fixed coefficient, 'q' is the electric charge of an electron, and 'r nm ' is the distance between two electrons e n and e m [28]. To compute the kink energy between electrons e X and e Y in Fig. 7 a and all other existing electrons of the input cells (e 1 , e 2 , e 3 , and e 4 ), an equal size of 'd' is assumed for all cell dimensions and the space between two adjacent cells is considered as 's'. ...
Regardless of the technology, the tristate logic is a crucial concept which facilitate bidirectional shared media access as an essential requirement for development of large-scale systems. Moreover, the tristate circuits significantly contribute to some advanced design topics such as wired logic and construction of basic components. Lack of a straightforward realization for the tristate logic is still a challenge in efficient development of some advanced topics such as shared media, and memory and I/O access mechanism in Quantum-dot Cellular Automata, as a tentative replacement candidate of the digital technology. A two-input tristate voter named as Z-Voter is introduced in this paper whose output is equal to both inputs in case of identical inputs. In case of different inputs, however, it does not enforce a strict ‘0’ or ‘1’ value on its output which resembles a high-impedance state. To demonstrate the Z-Voter correct functionality and applicability, it is utilized to propose a novel stand-alone efficient tristate buffer. Its main advantage with respect to other previous rivals is that it operates just similar to other conventional Quantum-dot Cellular Automata gates and does not rely on a special clocking mechanism. This simplifies its utilization for implementing larger systems. To demonstrate its correct operation as well as simple utilization, the introduced tristate buffer is exploited to implement a simple yet scalable shared media access control scheme. The simulation results of the proposed scheme with two and three simultaneously connected drivers are presented in the paper to demonstrate its scalability. The proposed Z-Voter and tristate buffer are very compact and composed of 4 and 29 cells, respectively. Convenient kink energy proofs, as well as QCADesigner-E tool simulation results, prove the correct functionality and applicability of the proposed gates and circuits. The power analysis results of the circuits are also extracted using QCAPro.
... The number of these particles is about the concentration of adsorbate particles, defined beforehand. Each particle is assigned a velocity according to the Maxwell-Boltzmann distribution [13]. For each axial direction, a random number is produced for each particle that shows the probability of movement in that direction. ...
Lithium-ion batteries are the dominant energy storage tools for electric vehicles and portable devices. Their prospects depend on the development of new electrode materials. The electrode properties are highly affected by phenomena on the electrode’s surfaces. Besides experimental means, there are various simulation ways to investigate these phenomena where experiments have difficulty analyzing. However, simulating some of these events is challenging for existing simulation methods, and researchers are looking for new simulation tools to fill this gap. Here, we focus on developing and evaluating a new method for studying the key surface phenomenon inside a battery electrode in nanoscale, i.e., adsorption. In particular, we are interested in the adsorption behavior of ions on the surface of a nanosized electrode. We developed a general cellular automata model for studying the adsorption behavior of various materials, where desorption and intercalation happen during an adsorption process. The model results are compared with Freundlich isotherm and show a high resemblance. Also, an experiment concerning the lithium-ion adsorption on Titania nanotube is modeled with our C.A. model. The model is highly time-efficient and exhibits spectacular performance for simulating relatively complex systems as the results are quite close to the experimental results. As this model is general, its local rules and parameters can be modified and calibrated easily with either experiment or simulation, enabling one to study various sorption behaviors.
... Classical molecular kinetic theory [1,2,5] holds that the thermodynamic temperature of an ideal gas is directly proportional to the average kinetic energy of a large number of molecules. This qualitative conclusion is true. ...
The unitary principle test of the pressure equation of ideal gas gives a negative conclusion, so I systematically revise the basic equation of molecular dynamics. The specific logic and conclusions are as following. The classical molecular dynamics theory established the wrong physical model of uniform motion of molecules under the action of an equivalent constant force, and the classical equations of ideal gas pressure and temperature derived from this model that violates the principle of mechanics is all incorrect. A variety of physical models of molecular interaction in accordance with the mechanical principle is established, and the correct equation of ideal gas pressure is derived consistently. It is proved that the pressure of an ideal gas is equal to the molecular energy per unit volume, and the thermodynamic temperature of an ideal gas is equal to the quotient of molecular average kinetic energy and Boltzmann constant. Various inferences of different models are consistent, so they comply with the unitary principle. Finally, I introduce the problem of the definite solution of the gas molecular rate distribution function that meets the limit condition of the speed of light, and put forward experimental suggestions to verify the theoretical gas temperature correction equation.
【Citation: Dongfang, X. D. Dongfang Modified Equations of Molecular Dynamics. Mathematics & Nature 1, 202104 (2021).】
... This area became the least of shadowing, throughout the day. The asphalt pavement characteristics in this area had relatively high heat capacity, automatically affecting the thermal environment, as an effective heat absorbent and producer (Halliday et al., 2007). Also, Figure 9 showed that the differences in character of the land cover material, had different effects on thermal condition. ...
Campus building was a place to accommodate various educational activities, which were both carried out indoors and outdoors. The environment, including the building and its exterior, provided thermal comfort that was influenced by the context, such as the mass of the facility, vegetation, and constructing envelope materials. The microclimate also influenced the environment, such as temperature, wind speed, and humidity. This study aimed to investigate the outdoor thermal comfort of campus building in urban area during summer, while also identifying the influential factors. This research referred to a case study, examining the thermal quality of the educational building environment using ENVI-met software, based on the Predicted Mean Vote (PMV) index as an indicator of outdoor thermal comfort, in Universitas Kebangsaan (UK). The results showed that the outdoor environment had low thermal comfort conditions during the day, as it also had different thermal satisfactory situations, due to differences in physical characteristics in each zone. This characteristics included, (1) The SVF determinant as indicators of the shading factor should be supported by the presence of vegetation and the use of pavement material, (2) Although the wind speed factor does not really affect the thermal comfort in the outdoor space, the interconnection between open gaps is likely to make breeze distribution in the area better. This study offered direction for campus planning, in order to maintain the optimal capacity of the natural environment, such as (1) Strategizing to create a better shadowing factor in the outer space, which was supported by controlling the use of pavement materials, (2) Directing the density of buildings by making open spaces more permeable, in order for better wind distribution in the area. From this study, the campus current conditions and future design development potential was also observed.
... Unlike the BioHorizons, the Nucle-OSS uses Grade 4 titanium for the implant body and stainless steel for the implant analog. Thermal expansion and contraction of these parts are different, 46 and this may affect the RTVs. If a coolant had been used, the RTVs might have been affected because of the thermal stresses. ...
Statement of problem
Whether preparation of an implant abutment decreases the stability of the abutment screw joint is unclear.
Purpose
The purpose of this in vitro study was to evaluate the effect of the abutment preparation in laboratory conditions on the reverse torque value (RTV) of the abutment screw.
Material and methods
Sixty implants, implant analogs, and abutments obtained from 2 different manufacturers were used in the present study and divided into 2 groups (groups B and N) according to the manufacturer. Each group was then divided into 3 subgroups (n=10) according to the remaining wall thickness (control, 0.4 mm, 0.6 mm). All abutments were tightened to analogs with 15 Ncm, and standardized preparation was made with a custom-designed copy-milling system. All abutments were tightened to the implants with 30 Ncm, and then, the abutment screws were removed and RTVs were recorded. Subgroups were analyzed by using 1-way ANOVA (α=.05), and the independent-sample t test was used to compare groups. Relationships between categorical variables were analyzed by chi-square tests. One abutment screw from each subgroup was randomly selected and analyzed by using a scanning electron microscope.
Results
A statistically significant difference was found between RTVs of different manufacturers (group B=28.2 ±1.2 Ncm, group N=25.9 ±1.4 Ncm; P<.005). In group N, there was a significant difference among subgroups, control (26.7 ±1.4 Ncm), and 0.6-mm wall thickness (24.8 ±0.8 Ncm) (P<.05). A statistically significant relationship was found between preparation and RTV for the NucleOSS only (P<.05) and between manufacturer and RTV (P<.001). Scanning electron microscopy evaluations identified different screw head and thread designs.
Conclusions
The abutment screw joint stability of the BioHorizons implant was not affected by abutment preparation.
Clinical Implications
... ¿A qué distancia deberá ubicarse el hombre con su balón tal que, al soltarlo, éste se quede quieto flotando en el aire y no sea atraído por la fuerza gravitacional de la Tierra? (Halliday & Resnick, 2013). ...
The target of this article is to present a methodology for solving problems, such as those used in basic sciences, inherited from modern computational thinking and applicable to any area of knowledge. To achieve this, tests were conducted with different groups of students with which some quantitative and qualitative results were obtained that allowed some inferences to be made not only in terms of effectiveness but also in terms of the effect on learning of a parametric methodology such as IPÜ (input - process - output) that allows, simply to have elements of judgment to know where to start the process of solving a problem, how to proceed with this start and to arrive at a response that solves the problem statement. The results conclude that while the students have a parametric methodology to solve sentences, problems, situations and exercises, it will be much easier to solve problems and, in addition, they will be able to appropriate the computational thinking, so necessary in times in which new technologies we can find in all corners of society and their needs.
... Since the strain term in equation (10) changes linearly with the z-coordinate, we can use its mean value at the center of the nth layer; the z-coordinate of the center of nth layer is denoted as z Tn . Next, the fundamentals of electricity state (see, for example, Walker et al., 2014) imply that the integration of E z over the thickness of a particular layer yields the voltage drop in such a layer. In order to make D z independent of the z-coordinate, E z must be a linear function of this coordinate with the mean value of at the center of nth layer given by ...
The article focuses on a modeling and subsequent optimization of a novel layered architecture of the vibration piezoceramic energy harvester composed of ZrO2/Al2O3/BaTiO3 layers and containing thermal residual stresses. The developed analytical/numerical model allows to determine the complete electromechanical response and the apparent fracture toughness of the multilayer vibration energy harvester, upon consideration of thermal residual stresses and time-harmonic kinematic excitation. The derived model uses the Euler–Bernoulli beam theory, Hamilton’s variational principle, and a classical laminate theory to determine the first natural frequency, steady-state electromechanical response of the beam upon harmonic vibrations, and also the mechanical stresses within particular layers of the harvester. The laminate apparent fracture toughness is computed by means of the weight function approach. A crucial point is the further optimization of the layered architecture from both the electromechanical response and the fracture resistance point of view. Maximal allowable excitation acceleration of the harvester upon which the piezoelectric layer will not fail is determined. It makes possible to better use the harvester’s capabilities in a given application and simultaneously guarantee its safe operation. Outputs of the derived analytical model were validated with finite element method simulations and available experimental results, and a good agreement between all approaches was obtained.
... obtained from the product catalog (data sheets). The density of the PAMPS was obtained using the Archimedean principle [58]. ...
The present research aimed to investigate the influence of layer arrangement and composition ratio on tensile and transport properties in bi-constituent electrospun nanofibrous membranes composed of polyurethane nanofibers with a hydrophobic nature and poly(2-acrylamido-2-methylpropanesulfonic acid) with a hydrophilic nature. Different hybrid electrospun nanofibrous membranes were produced based on different layer arrangement and composition ratios. To evaluate the membrane performance, their tensile strength, wind, and waterproof performance were measured. By adding 50% poly(2-acrylamido-2-methylpropanesulfonic acid) to polyurethane, the pore size of the hybrid electrospun nanofibrous membranes decreased by 47.64%. As a result, compared with pristine polyurethane membranes, hybrid electrospun nanofibrous membranes showed a good (9.6 mm s ⁻¹ ) windproof performance. Adding poly(2-acrylamido-2-methylpropanesulfonic acid) nanofibers to the polyurethane resulted in a decrease in mechanical properties and waterproof performance. The results show that the volume fraction of the poly(2-acrylamido-2-methylpropanesulfonic acid) and the electrospinning scenarios have a great influence on the mechanical properties of the samples. The results also show that the mechanical properties of hybrid electrospun nanofibrous membranes can be predicted based on the geometrical properties of each component. Computational fluid dynamics were used to simulate air flow through a virtual medium and the results of simulation were compared with the experimental measurement and predicted permeability; then, the best models for predicting air permeability were determined. In addition, based on different types of use, duration of use, and relative humidity level, a bi-functional membrane can be obtained by regulating layer arrangement and composition ratios to suit various applications, for example, in medical disposable clothing, wound dressing, filtering industries, and protective clothing.
... Boethius (6 th Century) inStrunk, O. (1981) 140 Boethius (6 th Century) inStrunk, O. (1981) 141 Kepler, (15 th Century) inKatz, R. and Dahlhaus, C. (1987) 142 Halliday, D. (2001) ...
This is a paper about the feeling of music. As many writers have discovered, it is difficult to explain the effects of music and even more difficult to try and categorise music itself. Therefore I do not wish to embrace the philosophical paradox of describing music; instead I wish to investigate the most basic feelings of music and work up to a subjective theory of music. In order to work up from the most basic origins of feeling, I believe it is necessary to understand feeling through the evolution of life. If the central tenet of evolution is correct, all aspects of life must originate from a single primal cell; therefore feeling must also have evolved from this primal cell.
In the first two chapters of this paper I will describe the most important aspects of cellular evolution and so form a basis for understanding the complexities of sensation. In order to make a thorough study I must first present a detailed analysis of research into the origins of life and early evolution of the cell. This will allow a characterisation of the primal cell and its reactions to vibration, the progenitor of music.
Having studied how the primal cell reacts to vibration, in the third chapter I will describe the cellular mechanisms which allowed the evolution of multi-cellular organisms and the development of more complex systems for dealing with sound. This will lead on to our own sensation of sound and our feeling of music.
As will become clear throughout the paper, the biological mechanisms are conserved from the very first organic molecules to the complex development of multi-cellular organisms and ourselves; it becomes apparent that feeling exists at a level beyond just life. Therefore, I will finish the paper with a discussion of physics and how musical acoustics and the feeling of music are the most useful models for understanding the smallest elements of physics. Furthermore, the physical feeling residing in these quantum effects can connect our own feeling of music and sensation to those of the primal cell and original molecules of life.
In this paper I will give a detailed account of the most recent scientific research on the evolution and development of the cell and the mechanisms involved in sensing vibration. In this way I will be able to give a thorough, scientifically reasoned account of musical
feeling. However, I do not expect this to detract from an artistic appreciation of music; I argue that both music and physics must be subjective and therefore can only be truly understood through feeling.
... Classical molecular dynamics theory [1][2][3] holds that the thermodynamic temperature of an ideal gas is directly proportional to the average kinetic energy of a large number of molecules. This qualitative conclusion is correct. ...
The unitary principle test of the pressure equation of ideal gas gives a negative conclusion, so the basic equations of molecular dynamics are systematically modified. The specific logic and conclusions are as following. The classical molecular dynamics theory established the wrong physical model of uniform motion of molecules under the action of an equivalent constant force, and the classical equations of ideal gas pressure and temperature derived from this model that violates the principle of mechanics is all incorrect. A variety of physical models of molecular interaction in accordance with the mechanical principle is established, and the correct equation of ideal gas pressure is derived consistently. It is proved that the pressure of an ideal gas is equal to the molecular energy per unit volume, and the thermodynamic temperature of an ideal gas is equal to the quotient of molecular average kinetic energy and Boltzmann constant. Various inferences of different models are consistent, so they comply with the unitary principle. Finally, the problem of the definite solution of the gas molecular velocity distribution function satisfying the limit condition of light speed is introduced, and the experimental suggestions to verify the ideal gas temperature correction equation are put forward.
... where S is the SVF of the ENMs, M is the mass of the sample in standard conditions (g), is computed on the basis of polymers' composition and densities (g/cm 3 ), A is the area of the specimen (cm 2 ), and T is the thickness of the sample (cm). The density of the PU was obtained from the data sheet and the density of the PAMPS was calculated by the Archimedean principle [50]. ...
This study aimed to examine the fabrication of bi-constituent nanofibrous membranes and investigation of their moisture management behavior in various environmental conditions. In doing so, polyurethane with a hydrophobic nature and superior mechanical behavior and poly(2-acrylamido-2-methylpropane sulfonic acid) (PAMPS) with a hydrophilic nature were utilized. Different hybrid electrospun nanofibrous membranes were aligned based on different layer arrangements and composition ratios. Then, the impacts of the solid fraction of polymers, sequence of stacking, and environmental conditions on water vapor permeability, contact angle, and acidic water permeation were measured and discussed. Tracing the water vapor permeability behavior in samples was carried out through measuring the amount of permeation hourly and proposing some regression models. Bi-modal nanofibrous membranes were successfully fabricated using PAMPS and polyurethane with an average fiber diameter of 543.5 and 216.7 nm, respectively. As the volume fraction of PAMPS increased, the porosities of the samples remained unchanged, the number of pores increased, and the pore size decreased (the average pore diameter was 299.97 nm for the PAMPS sample and 492.35 nm for the polyurethane sample). Despite the better water vapor permeability of the polyurethane membranes than that of the PAMPS membranes, in the first 12 h of the water vapor permeability test, the trend was completely reverse. The results also revealed that in the relative humidity of 55%, the polyurethane layer had the highest water vapor permeability among all samples. The results of the acidic water permeation and contact angle tests showed that the hybrid electrospun nanofibrous membranes exhibit better wicking and wetting properties.
... However, according to the equation of continuity, SV should be same anywhere along this closed circuit. 24,25 To maximize SV during CPR, SV of the LV and RV should be equalized. Otherwise, the less SV of either would limit the other by working as a stagnation point. ...
Objective:
Researchers have assumed that compressing the point beneath which the left ventricle (LV) diameter is maximum (P_max.LV) would improve cardiopulmonary resuscitation outcomes. Defining the midsternum, the currently recommended location for chest compression, as the reference (x = 0), the lateral deviation (x_max.LV) of personalized P_max.LV has become estimable using posteroanterior chest radiography. The authors investigated whether out-of-hospital cardiac arrest (OHCA) patients, whose x_max.LV was closer to the midsternum and thus had their P_max.LV compressed closer during cardiopulmonary resuscitation, showed better chances of return of spontaneous circulation (ROSC) and survival to discharge.
Design:
Retrospective, cross-sectional study.
Setting:
A university hospital.
Participants:
Adult OHCA patients with available previous posteroanterior chest radiography.
Intervention:
None.
Measurements and main results:
For each clinical outcome, multivariable logistic regression was performed, grouping x_max.LV into tertiles and adjusting the variables selected among the core elements of the Utstein template showing possible differences (p > 0.10) in univariate analysis. Odds ratios were presented as OR (95% confidence interval). Among 268 cases (age 64.4 ± 15.8 y, female 89 [33.2%]), 123 (45.9%) achieved ROSC and 40 (14.9%) survival to discharge. Compared with the third tertile of x_max.LV (59 to ∼101 mm), the first (31 to ∼48 mm) and second (48 to ∼59 mm) tertiles, which had a P_max.LV closer to the midsternum, were negatively associated with ROSC (OR 0.502 [0.262-0.960]; p = 0.037 and OR 0.442 [0.233-0.837]; p = 0.012, respectively) and survival to discharge (OR 0.286 [0.080-1.03]; p = 0.055 and OR 0.046 [0.007-0.308]; p = 0.002, respectively).
Conclusions:
OHCA patients with a P_max.LV located closer to the midsternum showed worse chances of ROSC and survival to discharge, which challenges the traditional assumption of identifying P_max.LV as the optimum compression point.
... En donde la fuerza & *+ ejercida por el objeto 1 sobre el objeto 2, es igual en magnitud y dirección, pero está en el sentido opuesto a la fuerza & +* ejercida por el objeto 2 sobre el objeto 1. Hasta aquí se ha hablado de la acción de las fuerzas sobre un cuerpo, sin embargo, cuando dos cuerpos interactúan, es decir, cuando por cada cuerpo se resiente una fuerza ligada al otro; la tercera ley de Newton explica el fenómeno planteando que: por cada acción existe una reacción igual en magnitud y opuesta en dirección, la acción es siempre igual a la reacción (Halliday et al, 2014). ...
La educación superior es el objeto de un número creciente de investigaciones a nivel internacional. Sin embargo, cabe resaltar que las prácticas pedagógicas de los profesores universitarios, en articular en física, en cursos magistrales y con un enfoque didáctico, siguen estando inexploradas. Nuestra investigación se inscribe en ese contexto. En tanto que heurística, busca la creación de una metodología de análisis cualitativo de cursos magistrales diseñados y desarrollados por profesores universitarios de física. Escogimos concentrarnos en el análisis de las prácticas pedagógicas efectivas de cuatro profesores universitarios de física en Francia y en Colombia en el marco de un curso magistral de primer año (enseñanza de la mecánica Newtoniana) apoyándonos en la pregunta: ¿Cuáles son las estrategias que los profesores universitarios utilizan para llevar a los estudiantes a la comprensión de los contenidos previstos en el curso? La noción de “proximidades discursivas” se moviliza acá para enriquecer los enfoques de modelización por intermedio de mapas conceptuales ya que permite especificar y comparar cada uno de los discursos analizados
... Polya's text aims to provide general problem-solving heuristics in all contexts, but since we are primarily discussing problem-solving in physics we can also turn to canonical introductions in physics to get a sense of physics problem-solving in particular. A 2014 AIP report (Tesfaye et al. 2014), cited Fundamentals of Physics (Halliday et al. 2010) as comprising a plurality of textbooks used by American high school teachers for Advanced Placement Physics C, the equivalent of a calculus-based 1st year college course. And yet, while Fundamentals of Physics includes on the order of a thousand physics problems, there is never a discussion of the general process by which students should solve problems. ...
Physics is often seen as an excellent introduction to science because it allows students to learn not only the laws governing the world around them, but also, through the problems students solve, a way of thinking which is conducive to solving problems outside of physics and even outside of science. In this article, we contest this latter idea and argue that in physics classes, students do not learn widely applicable problem-solving skills because physics education almost exclusively requires students to solve well-defined problems rather than the less-defined problems which better model problem solving outside of a formal class. Using personal, constructed, and the historical accounts of Schrödinger’s development of the wave equation and Feynman’s development of path integrals, we argue that what is missing in problem-solving education is practice in identifying gaps in knowledge and in framing these knowledge gaps as questions of the kind answerable using techniques students have learned. We discuss why these elements are typically not taught as part of the problem-solving curriculum and end with suggestions on how to incorporate these missing elements into physics classes.
... These findings, however, coincide with whereas they are shown to be much higher with respect to th in samples of meat from chicken and products derived from chicken. It has been demonstrated that virtually all the odorous substances found at spoilage could be attributed icrobial growth and metabolism [27]. Friedhoff et al. [8] have described the use of simple microbiological criteria, including aerobic mesophilic colony counts, Enterobacteriaceae some instances, enumeration of yeast to verify good manufacturing practices. ...
This paper is anattempt to determine the characterization properties of chickens sacrificed through three different methods: i) Muzekah (slaughtered within the fulfillment of Islamic requirements); Slaughtered without pronouncing the name of Allah(SWP), and Dead (died without slaughtering). In addition, readyfish, goat, sheep, cow and camel meats were collected from local markets. The densities, water holding capacity (WHC)and microbiological characteristics of chicken meats weremeasured and analyzed. The results indicate that the average densities of Muzekah meats havehighest densities which ranged (1068-1041 kg/m 3) followed by SWP chicken and Dead chicken that have densities 1036 and1021 kg/m 3 , respectively.
... The head rotating time was calculated based on the maximum linear velocity and stroke distance of the plunger. The maximum angular velocity (radian per second, rad/s) and maximum angular acceleration of head rotation (rad/s 2 ) were derived from the basic formula of angular velocity and angular acceleration (Halliday et al., 2013) as follows: ...
Abusive head trauma (AHT) is the leading cause of death from trauma in infants and young children. An AHT animal model was developed on 12-day-old mice subjected to 90° head extension-flexion sagittal shaking repeated 30, 60, 80, and 100 times. The mortality and time until return of consciousness were dependent on the number of repeats and severity of the injury. Under 60 times of repeated head shakings, the pups demonstrated apnea and/or bradycardia immediately after injury. Acute oxygen desaturation was observed by pulse oximetry during respiratory and cardiac suppression. The cerebral blood perfusion was assessed by laser speckle contrast analysis (LASCA) using the PeriCam PSI system. There was a severe reduction in cerebral blood perfusion immediately after the trauma that did not significantly improve within 24 hours. The injured mice began to experience reversible sensorimotor function at 9 days post-injury (dpi) which completely recovered at 28 dpi. However, cognitive deficits and anxiety-like behavior remained. Subdural/subarachnoid hemorrhage, damage to the brain-blood barrier, and parenchymal edema were found in all pups subjected to 60 insults. Pro-inflammatory response and reactive gliosis were up-regulated 3 dpi. Degenerated neurons were found in the cerebral cortex and olfactory tubercles at 30 dpi. This mouse model of repetitive brain injury by rotational head acceleration-deceleration partially mimics the major pathophysiological and behavioral events that occur in children with AHT. The resultant hypoxia/ischemia suggests a potential mechanism underlying the secondary rotational acceleration-deceleration induced brain injury in developing mice.
“Um ato de desespero” é a citação mais associada a Planck em relação ao seu postulado. Não sem razão: ela é representativa do que diz respeito ao caráter simultaneamente chocante e esclarecedor do quantum da ação. Ao enfatizar tal sentimento, esta citação parece pintar o esforço científico em cores vivas, subjetivas e, portanto, irracionais. A Palestra Nobel de Planck, por mais rica que seja em expressões de surpresa, pode, de forma interessante e irônica, levar-nos a uma imagem muito diferente da ciência; através de seu processo de racionalização, ele enuncia as evidências, métodos e valores que tiveram que ser manipulados para que o quantum de ação mostrasse seu significado e potencial. A perspectiva de Laudan da ciência como uma atividade racional e de resolução de problemas concede um contexto interessante a esta racionalização; articulando o modelo às palavras de Planck, pode-se ver que, embora as hipóteses científicas possam por vezes ser quase inacreditáveis e a subdeterminação possa tornar a ciência desesperante, é precisamente no erro e na divagação que a racionalidade pode residir. A Conferência Nobel de Planck pode ser uma fonte interessante para o ensino por casos históricos, porque associa aspectos cognitivos àqueles interpretados como humanos, num episódio histórico já bem recebido no ensino de física.
This paper presents an analysis of the conceptual design of a novel silicon suspension for the cryogenic test-mass mirrors of the low-frequency detector of the Einstein Telescope gravitational-wave observatory. In traditional suspensions, tensional stress is a severe limitation for achieving low thermal noise, safer mechanical margins and high thermal conductance simultaneously. In order to keep the tensional stress sufficiently low, we propose the use of rigid beams with large cross sections, combined with short flexures under compressional load. This configuration takes advantage of the many times higher strength of silicon in compression to respect to its strength in tension. The flexures are mechanically robust and at the same time soft in the working direction, thus producing low suspension thermal noise and, by being short, provide high thermal conductance for cryogenic cooling. The rigid beams, located between the test mass and an intermediate mass, allow the elimination of the recoil mass used conventionally for applying control forces for interferometer lock, and the use of optical anti-springs to reduce the pendulum resonant frequency to further improve the vibration isolation of the test mass. The configuration has the capability to reach a lower mirror operational temperature, which is expected to produce a substantial reduction of the thermal noise in the mirrors of the interferometer.
Zusammenfassung
In dieser Studie analysieren wir den Beitrag von Experimentalpraktika zur Entwicklung der professionellen Kompetenz angehender Lehrkräfte des Faches Physik. Experimentalpraktika verfolgen verschiedene Ziele, die sowohl das fachliche Lernen als auch die Entwicklung positiver motivationaler Orientierungen adressieren. Beide Aspekte sind zentrale Facetten der professionellen Handlungskompetenz von Lehrkräften. Während in einzelnen Laborstudien die Wirksamkeit von lehramtsspezifischen Praktika gezeigt werden konnte, ist der Beitrag dieses Lehrveranstaltungsformat für die Entwicklung der angehenden Lehrkräfte im Feld noch weitgehend unklar. Zur Untersuchung der Qualität von Experimentalpraktika wurden daher N = 105 Qualitätseinschätzungen Physiklehramtsstudierenden analysiert und gleichsam deren Bedeutung für die Entwicklung im Fachwissen, Interesse und Selbstwirksamkeitserwartungen im Laufe eines Studienjahres untersucht. Die Ergebnisse zeigen, dass Lehramtsstudierende der Physik die Qualität von Experimentalpraktika als relativ hoch bewerten. Mit Hilfe von linearen Regressionsgleichungen konnte zudem gezeigt werden, dass ein Zuwachs im Bereich der Selbstwirksamkeitserwartungen beim Planen und Durchführen von Experimenten für den Physikunterricht nach Besuch eines qualitativ hochwertigen Experimentalpraktikums erfolgt. Demgegenüber konnte kein signifikanter Einfluss auf den Fachwissenserwerb und die Interessensentwicklung gefunden werden.
Land cover change and climate change lead to rising land surface temperatures. An abundance of research demonstrates that urban vegetation, known as green infrastructure, can reduce land surface temperatures. However, there is little research determining how the spatial structure and pattern of urban vegetation affects land surface temperature. This research focuses on investigating the effects of urban vegetation patterns on land surface temperatures by comparing classification maps, spatial patterns of vegetation, and the land surface temperature contour maps. Eight areas that have similar land cover ratios but different spatial patterns have been selected. The results show that large vegetation patches reduce surface temperature better than small vegetation patches. A large vegetation patch has the ability to decrease surface temperature only in the patch itself, and at a distance of 60–120 m surrounding the patch. However, built-up and bare soil areas that reside next to the green patch still retain a high surface temperature. On the other hand, the maximum temperature of areas comprising the small vegetation patches is lower than the large patch. Overall, small, scattered vegetation patches reduce the surface temperature not only on the patches themselves but also in a wider area. It seems that small, scattered vegetation patches benefit the urban areas by reducing land surface temperature more than a large vegetation patch. However, both large and small, scattered vegetation patches should be combined to most efficiently decreasing urban land surface temperature. The findings of the research can be applied to Bangkok’s green infrastructure planning to improve the quality of life for the people and make the city more resilient.KeywordsUrban vegetationGreen infrastructureLandscape ecologyLand surface temperatureSpatial pattern of urban vegetationLand cover classification
Almost everyone knows about magnetic materials and the magnetic force, but very few are familiar with the underlying mechanisms that cause the magnetic force. The existence of an inextricable correlation between electricity and magnetism is the key to understanding this phenomenon. In general, the magnetic materials in the micro or macroscopic scale are classified into five distinct groups based on their response to an externally applied magnetic field. They are diamagnetic, paramagnetic, ferromagnetic, anti‐ferromagnetic, and ferromagnetic. Understanding the concept of the intrinsic and extrinsic properties of magnetic materials is important to handle the microstructure and thus their application. The intrinsic properties of a material are typically dependent on the chemistry and crystal structure such as crystal anisotropy, magnetostriction, and magnetostatic energy. While the extrinsic parameters such as pores, inclusions, and the nature of grain boundaries are highly microstructure sensitive.
In recent years, gestural interfaces have become quite popular. This type of interface exploits gestures, natural for most users, to create more innate and fluid interactions. This work introduces Capacitive Sensing as a low-cost, viable, and promising technique for the implementation of touchless gestural interfaces through the presentation of several projects that use this technology. In addition, it reports the experience of replicating an interface of this nature, pointing out the problems encountered as well as their solutions, advantages, and disadvantages.
In engineering field, some engineering problems can be solved by using arithmetic and algebra.
In this study, a device for free fall experiment has developed and implemented. A mobile Android application is developed in order to control the device via Bluetooth connection and see results of experiments in terms of measured time values, squares of measured time values and their graphs. Furthermore, a method is developed and implemented on embedded software in order to make it possible for more than one person groups to experiment using machine without interrupting each other’s work or taking each other’s pre-defined turn. Experimental results and comparison with theoretical calculations provided.
Daily ephemeris of Sun-Earth distances in two millennia (600–2600) showed significant decreases in February–June by up to 0.005 au in millennium M1 (600–1600) and 0.011au in millennium M2 (1600–2600). The Earth’s aphelion in M2 is shorter because shifted towards mid-July and longer because shifted to mid January naturally explaining two-millennial variations (Hallstatt’s cycle) of the baseline solar magnetic field measured from Earth. The S-E distance variations are shown imposed by shifts of Sun’s position towards the spring equinox imposed by the gravitation of large planets, or solar inertial motion (SIM). Daily variations of total solar irradiance (TSI) calculated with these S-E distances revealed TSI increases in February–June by up to 10–12 W / m 2 in M1 and 14–18 W / m 2 in M2. There is also positive imbalance detected in the annual TSI magnitudes deposited to Earth in millennium M2 compared to millennium M1: up to 1.3 W / m 2 , for monthly, and up to 20–25 W / m 2 for daily TSI magnitudes. This imbalance confirms an ascending phase of the current TSI (Hallstatt’s) cycle in M2. The consequences for terrestrial atmosphere of this additional solar forcing induced by the annual TSI imbalances are evaluated. The implications of extra solar forcing for two modern grand solar minima in M2 are also discussed.
This paper presents a smartphone application that displays an onscreen alert and emits a vibration if a car horn is triggered in the traffic, aiming to assist hearing impaired people in driving vehicles. The stages of the construction process are detailed and ways of obtaining the sound frequency of a real-time noise with algorithms using Fast Fourier Transform are discussed, as well as the crossing of these with usual frequency ranges in car horns. The paper also discusses the problems faced in the detection of frequency bands in real traffic, related to the Doppler effect. The testing methodology includes simulations and uses the application in a real traffic environment. As a result of this work we obtained a functional application, customizable by the user, capable of detecting automotive horns.
Skate é uma das culturas mais populares no Brasil, com mais de 8.5 milhões de adeptos. O movimento esportivo atualmente se encontra em uma fase de grande crescimento, dada inclusive a estréia da modalidade nos Jogos Olímpicos em Tóquio 2020. O presente estudo teve como objetivo desenvolver técnicas de detecção e classificação de manobras de Street Skate, utilizando sensores inerciais IMU (Inertial Module Unit) e Redes Neurais Artificiais (RNA). Utilizando conhecimento do estado da arte em detecção de movimentos no Skate, foram gerados 181 registros artificiais, resultando em 543 sinais de aceleração (X, Y e Z) divididos entre 5 classes de manobras. Foi desenvolvida uma heurística de classificação utilizando coeficientes de correlação cruzada para discriminar cada classe, e com a Neural Network Toolbox foi criada uma Multilayer Feed Forward Network de três camadas treinada através de um algoritmo de aprendizagem supervisionado (scaled conjugate gradient backpropagation). Os resultados mostraram que com a utilização de RNAs treinadas especificamente para cada eixo, sendo o eixo Z o maior discriminador, podemos alcançar um percentual de erro inferior a 0.05%, com uma eficiência computacional que disponibiliza respostas em tempo real. Aprendizado de máquina é uma podersoa ferramenta na classificação de padrões de movimento complexos, contanto que os classificadores sejam arquitetados de maneira eficiente e o problema proposto de maneira clara, essa técnica possui promissoras aplicações para Exergames e detecção de movimentos.
Bastnaesite (Ce0.50La0.25Nd0.20Pr0.05)CO3F is an interesting pattern family of (CO3)2− and F− co-existing phases, which is a meaningful sample to study the influence of multiple volatiles on minerals. Thermal stability of bastnaesite has been investigated by thermogravimetric experiment and in situ high-temperature Raman. The results demonstrate that bastnaesite undergoes a decarbonization transition at above 673 K. The isobaric-mode Grüneisen parameters range from 0.04 to 2.28. The compressibility of bastnaesite has been investigated by synchrotron radiation X-ray diffraction and Raman spectroscopy combined with diamond anvil cells up to 19.2 GPa at room temperature. Isothermal pressure–volume relationship of bastnaesite is fitted to the second-order Birch–Murnaghan equation of state with V0 = 430.87(3) Å3, K0 = 118.35(1) GPa. Its axial compressibility presents anisotropic, attributed to the rigid (CO3)2− group parallel to c-axis. Its isothermal-mode Grüneisen parameters and intrinsic anharmonic-mode parameters range from 0.23 to 1.91 and− 3.5 × 10−5 K−1 to 0.82 × 10−5 K−1, respectively. The presence of F− can largely enhance the thermal stability and incompressibility of minerals.
O crescimento da sociedade e o desenvolvimento de novas tecnologias implicaram no aumento da produção de equipamentos eletrônicos associado ao consumo de energia. Com a dominância da participação das fontes não renováveis na oferta mundial energética, presentes em quantidades limitadas, a sociedade busca por fontes alternativas de baixo custo e alta eficiência, como soluções para diminuição do impacto ambiental causado pelo aumento da poluição a nível mundial. A busca por energias renováveis de uso sustentável é a grande meta para o desenvolvimento de tecnologia mundial, preservando a Natureza. O presente trabalho apresentou como objetivo a construção e operação de um prot´tipo de equipamento para produzir e armazenar energia a partir de materiais recicláveis, pela adaptação das bicicletas ergométricas presentes em academias, para fins não comerciais. Foi utilizado um alternador automotivo ligado por uma corrente à roda da bicicleta ergométrica, cuja energia gerada foi armazenada em uma bateria do tipo ácido-chumbo. A montagem do equipamento foi realizada, onde foi observada a produção de energia em velocidades acima de 15 km/h, medida na própria bicicleta. Essa velocidade esteve relacionada com o número de giros no eixo do alternador. Nessas condições, o carregamento completo de um smartphone padrão foi realizado em 6 h. Não foi necessária geração constante de energia para alimentar o sistema, apenas em intervalos de 40 min durante todo o processo. O carregamento completo do mesmo aparelho smartphone em na rede elétrica residencial de 220 V, durou 4 h.
In the last century, the health of human beings has been affected by the industrial developments. Among some problems which jeopardize
human health, we must point to environmental pollution by making noise produced by artificial machineries like cars, buses, motorcycles, airplanes, etc.
Thus, we decided to study noise pollution in Zanjan. Here, we investigated the noise pollution of Zanjan Province to provide the rates of Noise levels
through the city during hours of different days. After collecting and analyzing data, we compared the final results of commercial, residential, and commercial
residential regions with prepared standards. The noise pollution rate of all regions was compared with the standards defined for the country. The most
effective factors on noise pollution were identified and its control methods were introduced. Finally, the noise pollution map of different regions are extracted
that can help to identify the best locations for health cares, marketing, etc.
Gout Arthritis is an articular disease caused by crystallization of monosodium urate (MSU) as the derivate of purine metabolism. The crystal formation is induced by the articular limb temperature which is lower than body temperature. Nowadays, thermotherapy has been performed by using temporary warmed substance, like the warmed water compress which contributes to patient's activity disruption. Cirofomite has been made as implanted thermotherapy device by producing heat around the ankle joint. The implanted part of this device can be controlled from smartphone by bluetooth connection and the power of the device can be recharged using a wireless charger. The design of Cirofomite has created by the following anatomical form of leg and ankle joint. This device is placed subcutaneously and implanted through two incisions, the first is on leg and the second close to medial malleolus. The silicone rubber coat used by this device aims to enhance flexibility and avoid body rejection. This device is designed to prevent the disruption of patient's activities when it has been used.
Cathodoluminescence (CL) and correlative light‐electron microscopy (CLEM) are two useful analytical tools in diverse research areas. Recently, fluorescent nanodiamonds (FNDs) have emerged as promising imaging agents for both CL and CLEM owing to their exceptional photophysical and chemical properties. However, to realize their practical applications in the life sciences, surface modification and functionalization of the nanomaterials with bioactive molecules are critical and essential. Here we provide a comprehensive review on the methods of synthesizing biohybrid FNDs as well as recent advances of CL and CLEM imaging of cells with these carbon nanoparticles as dual‐contrast markers.
In this paper, the Jacobian‐linearization‐ and feedback‐linearization‐based techniques of obtaining linearized model approaches are combined with a family of robust LQR control laws to identify the pairing which results in superior control performance of the bicycle robot, despite uncertainty and constraints, what is the main contribution of the paper. The control performance is analyzed using various indices, related, e.g. to energy consumption of the considered laws, with the experiments conducted on a real bicycle robot. As a result, the easily‐implementable controller is obtained, which requires only to perform a set of off‐line computations with a single additional parameter δ in comparison with a standard linear‐quadratic controller, to obtain a state‐feedback vector, which, when implemented to the control system, ensures proper regulation of the output signal of the plant, despite uncertainty or possible actuator failures, obtaining energy‐efficient control law.
The term “convection” is commonplace in groundwater science. The transport equation that we routinely use is sometimes called the “Convection‐Dispersion Equation”. The term convection also often arises in connection with variable density groundwater flow processes, where groundwater flow is driven by buoyancy differences in fluid, created by differences in temperature and/or concentration. In this variable density groundwater flow context, convection is actually shorthand for free (or natural) convection.
Most sensors have three functional parts: the sensor part, signal conditioning part and interface part (Fig. 1). The sensor part senses the physical phenomena and transforms it typically into electric form. The signal condition part amplifies, linearizes and scales the electric signal. The interface part can be a simple mechanical connector, (field) bus adapter or in a wireless sensor, a radio module. Signal conditioning and interface parts are in most cases implemented by electronics.
Microfluidics is the science and technology that process or manipulate small amounts of fluids from 10-6 to 10-12 l in the structures or channels that have at least one dimension in micrometer scale or less, or from 1 μm to 1 mm. There are two main kinds of microfluidic systems, termed as lab-on-a-chip (LC) and micro total analysis systems (μ-TAS). Mixing fluids (liquids and/or gases) is critical to develop microfluidic processes, including the driving power and the control system. The fluid mechanism in microfluidics may have some unique features related to the surface and interface. Driving forces from external environments are the first key parameter to promote the function of mass and heat exchange in microfluidic devices besides the reaction potentials. Mechanical performances, fluid mechanism, and physicochemical properties of materials have to be considered comprehensively in the design and fabrication of microfluidic devices.
In this study, an analysis of the structure of scientific explanations included in physics textbooks of upper secondary schools in Greece was completed, and the findings were used to recommend methods foruse in teaching scientific explanations, which methods have the potential to enhance students’ ability to understand, construct, and apply scientific explanations.In scientific explanations for specific phenomena found in the sample textbooks, the explanandum is a logical consequence of the explanans, which in all cases include at least one scientific law (and/or principle, model or rule) previously presented, as well as statements concerning a specific case or specific conditions. The same structure is also followed in most of the cases in which the textbook authors explain regularities (i.e. laws, rules) as consequences of one or more general law or principle of physics. Finally, a number of the physics laws and principles presented in textbooks are not deduced as consequences from other, more general laws, but they are formulated axiomatically or inductively derived and the authors argue for their validity. Since, as it was found, the scientific explanations presented in the textbooks used in the study have similar structures to the explanations in internationally-known textbooks, the findings of the present work may be of interest not only to science educators in Greece, but also to the community of science educators in other countries.
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