Journal articles on the topic 'Solid Mechanic'
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1
Pho, Nguyen Van. "A class of deterministic external problems equivalent to stochastic external problems in the reliability theory of mechanical systems." Vietnam Journal of Mechanics 13, no. 4 (December 31, 1991): 20–25. http://dx.doi.org/10.15625/0866-7136/10262.
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In this paper, the reliability of the Mechanic Systems is expressed under a new form. Then we propose au iterative method of computing of the Reliability, and apply the obtained results to the some problems of Solid Mechanics.
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González, E., and M. Sarrazin. "Solution of solid mechanic equilibrium problems by power series." International Journal of Computational Methods and Experimental Measurements 3, no. 1 (March 31, 2015): 33–48. http://dx.doi.org/10.2495/cmem-v3-n1-33-48.
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Wee Lee, Siong, Mohammad Hazizi Jamal, Mohd Amran Hasbullah, Mohd Johan Mohamed Ibrahim, Shahrul Nizam Mohammad, and Hairol Anuar Haron. "Forensic Investigation on The High Failure Rate of Civil Engineering Solid Mechanics Course." Asian Journal of University Education 17, no. 2 (June 6, 2021): 227. http://dx.doi.org/10.24191/ajue.v17i2.13402.
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Abstract: The attainment of program outcomes for Solid Mechanic course offered to the Diploma in Civil Engineering students is evaluated. It was found that most of the students were incapable to demonstrate graduate attributes which applying knowledge of mathematics, natural science and engineering fundamentals and the ability to analyse engineering problems. Therefore, this study investigates the impact of physics and maths scores on the students’ performance of solid mechanics. Analysis of the previous results in physics and maths shows that there is a clear link between students’ fundamentals knowledge and the understanding of solid mechanics. Meanwhile, this study also aims to find out the root causes that led to the high failure rate of solid mechanics. A quantitative method was employed and a total of 180 students responded to the survey. Results of survey indicate that most of the students perceived that they had limited time to gain deep understanding of the course and they could not visualise the complex problems in solid mechanics. Majority of the students admitted that they did not manage to solve all questions during their final exam, and they were indeed not well prepared for it. Hence, the problem of high failure rate is feasible to be solved provided both lecturers and students making efforts in striving the success of this course.
Keywords: Solid mechanics, Program outcomes, Failure rate, Problem solving, Applying knowledge
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Yang, Yongtao, Xuhai Tang, Hong Zheng, and Quansheng Liu. "Four-Node Quadrilateral Element with Continuous Nodal Stress for Geometrical Nonlinear Analysis." International Journal of Computational Methods 15, no. 02 (September 28, 2017): 1850005. http://dx.doi.org/10.1142/s0219876218500056.
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In this paper, the performance of a hybrid ‘FE-Meshfree’ quadrilateral element with continuous nodal stress (Quad4-CNS) is investigated for geometrical nonlinear solid mechanic problems. By combining finite element method (FEM) and meshfree method, this Quad4-CNS synergizes the individual strengths of these two methods, which leads to higher accuracy, better convergence rate, as well as high tolerance to mesh distortion. Therefore, Quad4-CNS is attractive for geometrical nonlinear solid mechanic problems where excessive distorted meshes occur. For geometrical nonlinear analysis, numerical results show that the results of Quad4-CNS element are much better than those of four-node isoparametric quadrilateral element (Quad4), and are comparable to quadratic quadrilateral element (Quad8) and other hybrid ‘FE- Meshfree’ elements.
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Koman, Bohdan, Olexiy A. Balitskii, and Volodymyr Yuzevych. "The Nature of Intrinsic Stresses in Thin Copper Condensates Deposited on Solid State Substrates." Journal of Nano Research 54 (August 2018): 66–74. http://dx.doi.org/10.4028/www.scientific.net/jnanor.54.66.
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Size effect for intrinsic stresses and thermodynamics of films formation established taking into account the nature of stresses in copper condensates deposited on solid state substrates. We believe that surface energy changes during layer by layer deposition in such condensates with chaotically dispersed areas (possessing different values of Young’s modulus) define the film’s mechanic parameters. The quantitative estimations of mechanical stresses are calculated for layer by layer film growth. The resulting intrinsic stresses (ISs) in copper condensates nature from local static ones, superposed within the area of a film. The latter arose due to anisotropy of interface interaction energy parameters.
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Flohr, Letícia, Armando Borges de Castilhos Júnior, and William Gerson Matias. "Acute and Chronic Toxicity of Soluble Fractions of Industrial Solid Wastes onDaphnia magnaandVibrio fischeri." Scientific World Journal 2012 (2012): 1–10. http://dx.doi.org/10.1100/2012/643904.
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Industrial wastes may produce leachates that can contaminate the aquatic ecosystem. Toxicity testing in acute and chronic levels is essential to assess environmental risks from the soluble fractions of these wastes, since only chemical analysis may not be adequate to classify the hazard of an industrial waste. In this study, ten samples of solid wastes from textile, metal-mechanic, and pulp and paper industries were analyzed by acute and chronic toxicity tests withDaphnia magnaandVibrio fischeri. A metal-mechanic waste (sample MM3) induced the highest toxicity level toDaphnia magna(CE50,48 h=2.21%). A textile waste induced the highest toxicity level toVibrio fischeri(sample TX2,CE50,30 min=12.08%). All samples of pulp and paper wastes, and a textile waste (sample TX2) induced chronic effects on reproduction, length, and longevity ofDaphnia magna. These results could serve as an alert about the environmental risks of an inadequate waste classification method.
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Arroyave, M., W. Perez, J. Quintero, S. Casanova, and A. Devia. "Mechanical Measurements of Multilayer Thin Films Obtained by a PAPVD System." Microscopy and Microanalysis 11, S03 (December 2005): 138–41. http://dx.doi.org/10.1017/s1431927605051081.
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The need of techniques for determining the mechanical properties of thin films, e.g. hardness coatings on ion beam treated surfaces has prompted a study of the microindentation hardness technique. The present interest is driven to a good understanding of the adhesion, friction, wear, and indentation processes. In most of the solid-solid interfaces of technological relevance, it occurs contact in many asperities, and this is why the study of fundamental properties of micro-mechanic and tribology of surfaces and interfaces is very important. The recent developments of different microscopic techniques based on tips and force surface devices (i.e. AFM, FM, LFM) allowed investigations of interfacial problems with high resolution and have led to the nanoscale regime the mechanical properties study for a wide spectrum of materials. In this work a method for Young's modulus determination of hard coatings multilayers of TiN/ZrN is evaluated. This method is based on AFM and spectroscopy-force modes [1-2].
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MIEshkov, Yurii, and Olga Voytovich. "CORRECT MECHANIC AND TECHNICAL CHARACTERISTICS OF «LAUNCH» AND «PEAK»." Herald of Khmelnytskyi National University. Technical sciences 313, no. 5 (October 27, 2022): 288–93. http://dx.doi.org/10.31891/2307-5732-2022-313-5-288-293.
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The article compares the mechanical and technical characteristics of car lifts used at all car service centers. Over the last 20 years, two-post lifts have taken their place and gained popularity, they have overtaken four-post lifts by more than three times, if only because they cost less. Two-post jacks were originally used to check and service oil, tires, etc., but are now widely used for major activities (although four-post jacks are still required for a full MOT). Nevertheless, many experts do not stop reporting the risk of falling vehicles from two-post lifts. There have been known cases over the past five years, when not only the car was damaged during the fall from the lift, but also the workers were seriously injured, and there were also fatal cases. Therefore, the opinion of the inspection department is that any fall of the vehicle from a height carries a high risk and fatal injuries. Manufacturers of medium and premium lifting equipment began to introduce budget models into their lines. They follow the path of structural simplification of models, reduce production costs, use cheaper metals, remove electronic systems, which allows to reduce the cost of equipment. The lift market shows almost no changes in terms of assortment. It is segmented according to the type of lifters – two-post, plunger, scissor, roll-up ditch, four-post, multi-post plunger. When considering the market of lifting equipment, one cannot ignore the Chinese car manufacturers, which occupy a solid share in the overall structure of this product group. “The Chinese equipment market is now clearly divided into two classes – one is represented by cheap and low-quality products, and the other is a segment of equipment of decent quality. There is a clear difference between the two segments that is clear to a professional. When choosing Chinese lifts, customers understand that if they ask for little money for the equipment, it will not last long. There is a lot of such low-quality equipment on the market, and this product generally discredits the entire segment from China.
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Sun, Guanhua, Yongtao Yang, and Hong Zheng. "A Three-Node Triangular Element with Continuous Nodal Stress (Trig3-CNS) for Geometry Nonlinear Solid Mechanics Problems." International Journal of Computational Methods 15, no. 04 (May 24, 2018): 1850022. http://dx.doi.org/10.1142/s0219876218500226.
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This paper investigates the performance of the three-node triangular element with continuous nodal stress (Trig3-CNS) for geometry nonlinear solid mechanic problems. This Trig3-CNS element was recently proposed to improve accuracy of the finite element method (FEM). By synergizing the individual strengths of meshfree method and FEM, the Trig3-CNS element achieves higher accuracy and convergence rate. Furthermore, Trig3-CNS presents high tolerance to mesh distortion. Therefore, it is potentially useful for geometry nonlinear solid mechanics problems in which mesh distortion takes place. Compared with the traditional hybrid “FE-Meshfree” elements, Trig3-CNS naturally processes CNS without requiring any extra operation in post-processing. Numerical tests in the present work show that for geometry nonlinear analysis, the results of the Trig3-CNS element are better than the 3-node triangular element (Trig3) and 4-node isoparametric quadrilateral element (Quad4). In addition, the performance of Trig3-CNS is comparable to that of traditional hybrid “FE-Meshfree” elements.
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Li, Bai Zhou, and Jia Jun Qiu. "Magnetism and Solid Coupling Vibration of Stator Double-Shell System of Asynchronous Machine." Applied Mechanics and Materials 300-301 (February 2013): 1193–99. http://dx.doi.org/10.4028/www.scientific.net/amm.300-301.1193.
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The electromagnetic force produced by air-gap eccentricity magnetic field includes kinds of frequencies, and excites multiform magnetism and solid coupling vibrations of stator system. In this paper, based on the improved model of double-shell system of asynchronous machine, the magnetism and solid coupling vibration equations of double-shell system are obtained. Considering the air-gap eccentricity, an improved expression of electromagnetic force is derived. Then the method of multiple scales is applied to solve the nonlinear parametric resonance. Through the numerical calculation, the influence of electromagnetic and mechanic parameters on amplitude- frequency characteristics is analyzed.
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Paprika, Milijana, Mirko Komatina, Milica Mladenovic, Goran Zivkovic, and Dragoljub Dakic. "Mechanism of primary fragmentation of coal in fluidized bed." Thermal Science 20, suppl. 1 (2016): 125–32. http://dx.doi.org/10.2298/tsci150603224p.
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In order to lay a foundation of a credible primary fragmentation model, a theoretical analysis of the thermo-mechanical processes in a devolatilizing solid fuel particle was carried out. The devolatilization model comprises heat transfer, chemical processes of generation of gaseous products of combustion (volatiles), volatile transfer, and solid mechanic processes. A spatial and temporal analysis of the stresses within the particle showed that the radial stress is caused primarily by the pressure of generated volatiles. This stress monotonously decreases from the particle center towards the particle surface, without changing its sign. The tangential stress is caused primarily by the thermal shock. Close to the surface, it changes its sign. In the particle cross-section, the radial stress prevails close to the particle center, whilst the tangential stress is dominant in the surface region. At the points where these stresses exceed the particle tensile strength, cracks occur. Cracks extend tangentially close to the surface, and radially close to the center of the particle.
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Ceradini, Vittorio, Michele Candela, and Roberta Fonti. "The Role of Solid Springer in Masonry Vault." Advanced Materials Research 133-134 (October 2010): 349–54. http://dx.doi.org/10.4028/www.scientific.net/amr.133-134.349.
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During a scientific research, directed to understand the structural role of some particular masonry elements, noticeable in covering structures like vault and dome, we searched the technical rules and function of these elements. We verified that in literature there is no specific documentation about these elements and its mechanic purposes. The study was directed to recognize the most representatives architectures in different ages, and to identify the construction technique’s evolution process of this particular arc-double or thickening of arc that we arrived to identify as a necessary building component to give balance in particular structural configuration. This process put down roots from the roman ancient age, until baroque age, where the most original applications of this regulation were placed. From Pantheon to the limit case of St. Filippo Neri chapel, the covers’ structures springer angle studied was analyzed together with its relation to plan, sections and elevation of all buildings. Therefore, if these elements are well-performed, they follow precise constructive patterns that this article would like to identify and show.
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Yu, Muchun, Xue Gao, and Qian Chen. "Study of the Mechanical Properties and Vibration Isolation Performance of a Molecular Spring Isolator." Shock and Vibration 2016 (2016): 1–10. http://dx.doi.org/10.1155/2016/6451829.
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Molecular Spring Isolator(MSI) is a novel passive vibration isolation technique, providingHigh-Static-Low-Dynamic(HSLD) stiffness based on the use ofmolecular springmaterial. Themolecular springmaterial is a solid-liquid mixture consisting of water and hydrophobic nanoporous materials. Under a certain level of external pressure, water molecules can intrude into the hydrophobic pores of nanoporous materials, developing an additional solid-liquid interface. Such interfaces are able to store, release, and transform mechanical energy, providing properties like mechanical spring. Having been only recently developed, the basic mechanic properties of a MSI have not been studied in depth. This paper focuses on the stiffness influence factors, the dynamic frequency response, and the vibration isolation performance of a MSI; these properties help engineers to design MSIs for different engineering applications. First, the working mechanism of a MSI is introduced from a three-dimensional general view of the water infiltration massive hydrophobic nanoporous pores. Next, a wide range of influence factors on the stiffness properties of MSI are studied. In addition, thefrequency response functions(FRFs) of the MSI vibration isolation system are studied utilizing the matching method based on equivalent piecewise linear (EPL) system. Finally, the vibration isolation properties of MSI are evaluated by force transmissibility.
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Vaisman, Ya I., V. N. Korotaev, D. L. Borisov, Ya V. Bazyleva, and V. G. Barannikov. "POSSIBILITIES FOR THE REDUCTION OF THE NEGATIVE IMPACT FROM THE USE OF SECONDARY FUEL FROM SOLID MUNICIPAL WASTE ON SANITARY CONDITIONS OF THE LIFE AND HUMAN HEALTH." Hygiene and sanitation 96, no. 3 (March 27, 2019): 197–202. http://dx.doi.org/10.18821/0016-9900-2017-96-3-197-202.
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There are considered possibilities of the reduction of the negative impact of the use of secondary fuels from solid municipal waste (SMW) on the sanitary conditions of the life and health through the application of the proposed technology for production of solid fuel of specified quality with the content of acceptable levels of hazardous components that determine the formation of emissions of priority pollutants under the use of the secondary fuel. There are presented results of investigations for the production of a proposed quality of secondary fuels from SMW with the use of the experimental-industrial complex for the optical and mechanical sorting of the waste. There is described the technology of the production of sanitary, toxicological and environmentally safe recycled fuel, based on the use of methods of optical-mechanic waste sorting and devices allowing to reduce in the secondary fuel, the content of chlorine-, mercury-and cadmium-containing components to the normative level and low-calorie roughage substances. There are given recommendations for the reduction of the anthropogenic impact on the population and objects of the environment to an acceptable level under the use of secondary fuels derived from SMW.
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Wang, G., and K. Liu. "Approach to the Improvement of Laser Cutting Accuracy for Laminated Solid Manufacture by Dynamic Compensation." Materials Science Forum 471-472 (December 2004): 736–40. http://dx.doi.org/10.4028/www.scientific.net/msf.471-472.736.
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Laser cutting process plays a key role in obtaining accurate parts in Laminated Solid Manufacture. Conventional laser cutting machine adopts motion control scheme. For further improving the cutting accuracy, dynamic factors are to be taken into account. The dynamic compensation scheme is proposed. The method combines the advantages of close-loop position control and computed torque control. Different from other presented schemes, the method is not model-based. A multilayer neural network is employed to realize the inverse mechanic dynamics. The complicated dynamic parameter identification problem becomes the learning process under supervision. Experiments have been conducted to verify the proposed method for improving the laser cutting accuracy.
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Mollendorf, J. C., J. D. Felske, S. Samimy, and D. R. Pendergast. "A Fluid/Solid Model for Predicting Slender Body Deflection in a Moving Fluid." Journal of Applied Mechanics 70, no. 3 (May 1, 2003): 346–50. http://dx.doi.org/10.1115/1.1554416.
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An analytical solution is presented for the steady-periodic shape variation of a thin elastic beam subject to fluid mechanic forces and driven by the motion imposed on its ends. The general solution is applicable to such problems as swim fins and aerodynamic flutter, with the proper choice of boundary conditions. The general results are exemplified here by using specific boundary conditions that mimic the motion of swim fins. The calculated instantaneous shape, position, slopes, and lateral velocities of the fin are compared with corresponding measurements taken from underwater video of fins worn by divers swimming at a controlled speed. The analysis revealed new swim technique parameters that characterize the heel slope and its phase with respect to the heel motion. The calculated power, thrust, and Froude efficiency are presented in terms of these parameters.
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Jaksic, Nikola, Henri Greuner, and Albrecht Herrmann. "FEM investigation and thermo-mechanic tests of the new solid tungsten divertor tile for ASDEX Upgrade." Fusion Engineering and Design 88, no. 9-10 (October 2013): 1789–92. http://dx.doi.org/10.1016/j.fusengdes.2013.04.048.
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Lei, Deng Sheng, Xiao Liang Huang, and Chun Bi Xu. "The Transporting Mechanic of Slurry of Heavy Oil and Sand in Horizontal Wellbore." Applied Mechanics and Materials 271-272 (December 2012): 641–44. http://dx.doi.org/10.4028/www.scientific.net/amm.271-272.641.
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It is a special modality of solid-fluid conduit flow for the sand transporting procedure in wellbore. Under the action of heavy oil, because of the difference of the borehole location, the transporting mechanic of sand is not the same. For the vertical wellbore, sand particles are mainly dominated by the drag forces and carried out of the hole; however, for the horizontal wellbore, sand particles are under complex forces and show different flow state. In different flow state, the sand particles are controlled by different forces, the heavy oil’s sand transporting capacity is changed. This paper begins with the analysis of the stress of the sand particles, and deeply analyses the vertical and horizontal wellbore, the stress of sand particles in the heavy oil’s sand mixing flow procedure, and then study the heavy oil’s sand transporting capacity.
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Šilhavý, Miroslav. "A variational approach to nonlinear electro-magneto-elasticity: Convexity conditions and existence theorems." Mathematics and Mechanics of Solids 23, no. 6 (April 19, 2017): 907–28. http://dx.doi.org/10.1177/1081286517696536.
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Electro- or magneto-sensitive elastomers are smart materials whose mechanical properties change instantly by the application of an electric or magnetic field. This paper analyses the convexity conditions (quasiconvexity, polyconvexity, ellipticity) of the free energy of such materials. These conditions are treated within the framework of the general A-quasiconvexity theory for the constraints [Formula: see text] where F is the deformation gradient, d is the electric displacement and b is the magnetic induction. If the energy depends separately only on F, or on d, or on b, the A-quasiconvexity reduces, respectively, to Morrey’s quasiconvexity, polyconvexity and ellipticity conditions or to convexity in d or in b. In the present case, the simultaneous occurrence of F, d and b leads to the cross-phenomena: mechanic–electric, mechanic–magnetic and electro–magnetic. The main results of the paper are as follows. In dimension 3 there are 32 linearly independent scalar A-affine functions (and 15 in dimension 2) corresponding to the constraints (*). Therefore, an energy function ψ ( F, d, b) is A-polyconvex if and only if it is of the form [Formula: see text] where Φ is a convex function (of 31 scalar variables). Apart from the expected terms F, cof F, det F, d and b, we have the cross-effect terms Fd, Fb (and in dimension 2 also d × b). An existence theorem is proved for a state of minimum energy for a system consisting of an A-polyconvex electro-magneto-elastic solid plus the vacuum electromagnetic field outside the body.
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Badur, Janusz, Michel Feidt, and Paweł Ziółkowski. "Duhem and Natanson: Two Mathematical Approaches to Thermodynamics." Energies 15, no. 5 (March 3, 2022): 1881. http://dx.doi.org/10.3390/en15051881.
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In this article, the previously unrecognized contributions of Pierre Duhem and Ladislavus Natanson in thermodynamics are shown. The mathematical remodelling of a few of their principal ideas is taken into consideration, despite being neglected in the literature. To emphasize these ideas in an appropriate epistemological order, it would be crucial to first revalue and reconstruct some underrepresented parts of the proceedings process through which Duhem and Natanson created their thermodynamics. Duhem and Natanson’s scientific works are against the background of modern continuum mechanics, presenting relevant approaches. In line with the long-held beliefs of many French and Polish researchers, the article mentions that Duhem and Natanson’s ideas dated back to one century ago. Both scientists were qualified in the same Royal Way, which in this case includes chemistry, mechanic of fluid and solid, electro-chemistry, thermodynamics, electrodynamics, and relativistic and quantum mechanics. Therefore, it is possible to connect and then compare the results of their conceptions and approaches. Duhem and Natanson are both in firm opposition with Newtonian mechanisms. Thus, the Maupertuis least action principle created the ground for their efforts, in which they flourished as an elementary quantum.
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Gamolin, O. Ye, A. K. Golovko, O. I. Lomovsky, and V. F. Kam'yanov. "Mechanically Activated Chemical Conversion of Gaseous Hydrocarbons." Eurasian Chemico-Technological Journal 5, no. 4 (April 6, 2016): 305. http://dx.doi.org/10.18321/ectj318.
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Propane-butane gaseous mixtures were subjected to mechanical treatment in centrifugal ball mill in the absence or presence of some mineral particles. It was found that the composition of gas mixture was changed significantly depending on duration of the mechanical coercion and solid or porous nature of mineral additives. The mechanical treatment of light hydrocarbons in the presence of quartz particles at the temperatures not exceeding 100 °C resulted at long last in complete conversion of initial organic compounds to methane, hydrogen and small amounts of carbon. The same alterations of gas composition were lesser profound when the mechanical treatment was carried out in the absence of minerals or in the presence of porous silica gel or aluminum oxide. It have been shown that direct transformation of mechanic energy to intramolecular energy of hydrocarbons is more responsible for their destruction during the process considered rather than catalytic properties of the minerals. The removal of heavier hydrocarbons from natural or casing-head petroleum gas by means of MA treatment permits to facilitate further gas transportation and to improve essentially its heat-physical properties, namely, to decrease gas average molecular mass and specific gravity and to increase its caloricity and Wobbe number' values.
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Su, Xin, De Jiang Li, Yan Cai Xie, Xiao Qin Zeng, and Wen Jiang Ding. "Effect of Sm on the Microstructure and Mechanical Property of Mg-xSm-0.4Zn-0.3Zr Alloys." Materials Science Forum 747-748 (February 2013): 238–44. http://dx.doi.org/10.4028/www.scientific.net/msf.747-748.238.
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The effect of Sm content (2, 4, 6, 8wt.%) on the microstructures and mechanic properties of gravity casting Mg-xSm-0.4Zn-0.3Zr alloys were investigated. The results showed that the cast alloy mainly consists of α-Mg matrix and Mg41Sm5 phase distributed at the grain boundaries, and the amount of the second phase increased with the rise of Sm content. After the solution treatment (T4), the second phase disappeared, however small amount of cuboid-like phase were found inside the grain, and its volume fraction also increases with the rise of Sm content. It is found in the age hardening curves of the alloys at 175, 200, and 225 °C that the alloys with various components almost showed the same trend of age hardening. While the higher the Sm content, the harder the alloy. With the Sm content increases, the yield strength (TYS) of cast alloys (F state) were obviously improved, however the tensile strength (UTS) became lower because of the quick drop of the elongation. The elongations of solid solution (T4) and aging (T6) alloy became lower, while the yield strength and tensile strength increased at first and then decreased. The optimized component is Mg-4Sm-0.4Zn-0.3Zr, which the mechanic properties at T6 state are: TYS=131MPa; UTS=261MPa; δ=6.8%.
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Chu, Yun Peng, Yong Yao, and De Bin Li. "Seismic Behavior Study on Improving Beam-Column Connections in Portal Frames." Advanced Materials Research 368-373 (October 2011): 881–84. http://dx.doi.org/10.4028/www.scientific.net/amr.368-373.881.
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The beam-column joints of steel solid-web portal frame has high stress concentration, which cause brittle fracture of plate under reciprocating load. Low reciprocating load test and finite element analysis for three kinds of joints, Discussing the ultimate bearing capacity, hysteretic performance and fracture mechanic properties, Which the results shows that: the bearing capacity of improved joint has grater increased than the joint with endplate keep upright; when load to limit state, the flange plate of joint with endplate keep upright has strong fracture performance, this point has been proved during the experiments; According to the numerical distribution of cracks factor, can qualitative identify dangerous position of component, as a basis of fracture fortification for structure.
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Mohammadyari, Reza, Mazaher Rahimi Esboee, and Majid Rahgoshay. "Analytical solution of settling behavior of a particle in incompressible Newtonian fluid by using Parameterized Perturbation Method." Boletim da Sociedade Paranaense de Matemática 33, no. 2 (August 18, 2014): 145–60. http://dx.doi.org/10.5269/bspm.v33i2.22833.
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The problem of solid particle settling is a well known problem in mechanic of fluids. The parametrized Perturbation Method is applied to analytically solve the unsteady motion of a spherical particle falling in a Newtonian fluid using the drag of the form given by Oseen/Ferreira, for a range of Reynolds numbers. Particle equation of motion involved added mass term and ignored the Basset term. By using this new kind of perturbation method called parameterized perturbation method (PPM), analytical expressions for the instantaneous velocity, acceleration and position of the particle were derived. The presented results show the effectiveness of PPM and high rate of convergency of the method to achieve acceptable answers.
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Lignola, Gian Piero, Andrea Prota, and Gaetano Manfredi. "Influence of Masonry Properties on Confinement: A Mechanical Model." Key Engineering Materials 624 (September 2014): 299–306. http://dx.doi.org/10.4028/www.scientific.net/kem.624.299.
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Design provisions for the repair, retrofitting, and rehabilitation of existing masonry structures are not always available and included in International and National Building Codes. Due to the extremely large variability in masonry performances, equations of general validity cannot be provided, namely relationships suitable for confinement of every masonry type, as it is done for concrete. Large amount of results obtained for concrete led to consolidated design guidelines. Despite the great research effort in the experimental field on masonry, considerable theoretical work is still needed to fully outline a definitive analytical model to predict the behavior of FRP confined masonry. In this study, a mechanically based confinement model is proposed based on mechanical parameters able to differentiate similar masonry types and to highlight that they present different confinement performance. The most relevant parameters are the compressive and tensile strength of unconfined masonry and they are discussed in the framework of solid mechanic based models based on triaxial plasticity and calibrated experimentally. The proposed approach can then be extended to other masonry types.
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Hu, Yan-Ling, Yuqin Zhu, Huayu Ji, Qingyuan Luo, Ao Fu, Xin Wang, Guiyan Xu, et al. "Fabrication of InxGa1−xN Nanowires on Tantalum Substrates by Vapor-Liquid-Solid Chemical Vapor Deposition." Nanomaterials 8, no. 12 (November 29, 2018): 990. http://dx.doi.org/10.3390/nano8120990.
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InxGa1−xN nanowires (NWs) have drawn great attentions for their applications in optoelectronic and energy conversion devices. Compared to conventional substrates, metal substrates can offer InxGa1−xN NW devices with better thermal conductivity, electric conductivity, and mechanic flexibility. In this article, InxGa1−xN NWs were successfully grown on the surface of a tantalum (Ta) substrate via vapor-liquid-solid chemical vapor deposition (VLS-CVD), as characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), scanning and transmission electron microscope (STEM), and photoluminescence spectroscopy (PL). It was found that the surface pretreatment of Ta and the composition of metallic catalysts played important roles in the formation of NWs. A dimpled nitrided Ta surface combined with a catalyst of nickle is suitable for VLS-CVD growth of the NWs. The obtained InxGa1−xN NWs grew along the [1100] direction with the presence of basal stacking faults and an enriched indium composition of ~3 at.%. The successful VLS-CVD preparation of InxGa1−xN nanowires on Ta substrates could pave the way for the large-scale manufacture of optoelectronic devices in a more cost-effective way.
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Khajehtourian, Romik, Saeed Adibnazari, and Samaneh Tashi. "The Sliding Frictional Contact Problem in Two Dimensional Graded Materials Loaded by a Flat Stamp." Advanced Materials Research 463-464 (February 2012): 336–42. http://dx.doi.org/10.4028/www.scientific.net/amr.463-464.336.
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In this article, the sliding frictional contact problem for a half-plane which is graded in two dimensions is studied. The effect of medium properties gradient and coefficient of friction in contact mechanics of two dimensional (2D) graded materials which is loaded by a flat stamp have been investigated by developing two Finite Element (FE) models, in macro and micro scales. Discretizing the graded half- plane by quadrants for whose material properties are specified at the centroids by Mori-Tanaka method in both directions has been used to model the 2D FGM in macro scale. In micro scale, the ideal solid quadrant particles which are spatially distributed in a homogeneous matrix used to model the FGM structure. Also, boundary conditions and loading of both models are the same. The study is focused on determining the contact stress distributions on contact surface. The contact mechanic problem of 2D graded materials has been solved and the results are presented for various combinations of friction coefficient and material non-homogeneity constant parameters Analyses and comparison of the results showed that micro and macro scale results are in a very good agreement.
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Tumino, Davide, Tommaso Ingrassia, Vincenzo Nigrelli, and Giovan Battista Trinca. "Redesign of a Reverse Shoulder Prosthesis: Kinematic and Mechanical Study." Applied Mechanics and Materials 670-671 (October 2014): 847–51. http://dx.doi.org/10.4028/www.scientific.net/amm.670-671.847.
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In this work a commercial reverse shoulder prosthesis has been redesigned to improve performances in terms of range of movements of the implant and stability to dislocation. A kinematic and mechanic study has been performed using a realistic solid model of the prothesised shoulder: in particular, all the components of the prosthesis have been acquired via a 3D laser scanner and inserted in a virtual humerus-glenoid system by reproducing the common surgical procedure. The final model has been used to measure the maximum angles of abduction and rotation of the arm and the shear forces that cause dislocation. Modifications proposed to the commercial prosthesis are: a different orientation of the cutting plane of the glenoid component and the interposition of a spacer to move the center of rotation of the arm.
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Travascio, Francesco, Shihab Asfour, Roberto Serpieri, and Luciano Rosati. "Analysis of the consolidation problem of compressible porous media by a macroscopic variational continuum approach." Mathematics and Mechanics of Solids 22, no. 5 (December 23, 2015): 952–68. http://dx.doi.org/10.1177/1081286515616049.
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This study presents an analysis of the stress-partitioning mechanism for fluid saturated poroelastic media in the transition from drained (e.g. slow deformations) to undrained (e.g. fast deformation) flow conditions. The goal of this analysis is to derive fundamental solutions for the general consolidation problem and to show how Terzaghi’s law is recovered as the limit undrained flow condition is approached. The approach is based on a variational macroscopic theory of porous media (VMTPM). First, the linearized form of VMTPM is expressed in a u– p dimensionless form. Subsequently, the behavior of the poroelastic system is investigated as a function of governing dimensionless numbers for the case of a displacement controlled compression test. The analysis carried out in this study produced two crucial results. First, in the limit of undrained flow, it confirmed that the solutions of the consolidation problem recover Terzaghi’s law. Second, it was found that a dimensionless parameter ([Formula: see text]), which solely depends on mixture porosity and Poisson ratio of the solid phase, discriminates two diametrically opposed mechanic responses of the poroelastic system. More specifically, when [Formula: see text] is positive, the solid stress in the mixture first increases and then relaxes to an equilibrium value ( stress relaxation). In contrast, when [Formula: see text], the solid stress monotonically tenses up to reach the equilibrium value ( stress tension).
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Zhang, Rui, Dianlei Han, Songsong Ma, Gang Luo, Qiaoli Ji, Shuliang Xue, Mingming Yang, and Jianqiao Li. "Plantar pressure distribution of ostrich during locomotion on loose sand and solid ground." PeerJ 5 (July 25, 2017): e3613. http://dx.doi.org/10.7717/peerj.3613.
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BackgroundThe ostrich is a cursorial bird with extraordinary speed and endurance, especially in the desert, and thus is an ideal large-scale animal model for mechanic study of locomotion on granular substrate.MethodsThe plantar pressure distributions of ostriches walking/running on loose sand/solid ground were recorded using a dynamic pressure plate.ResultsThe center of pressure (COP) on loose sand mostly originated from the middle of the 3rd toe, which differed from the J-shaped COP trajectory on solid ground. At mid-stance, a high-pressure region was observed in the middle of the 3rd toe on loose sand, but three high-pressure regions were found on solid ground. The gait mode significantly affected the peak pressures of the 3rd and 4th toes (p = 1.5 × 10−6and 2.39 × 10−8, respectively), but not that of the claw (p = 0.041). The effects of substrate were similar to those of the gait mode.DiscussionGround reaction force trials of each functional part showed the 3rd toe bore more body loads and the 4th toe undertook less loads. The pressure distributions suggest balance maintenance on loose sand was provided by the 3rd and 4th toes and the angle between their length axes. On loose sand, the middle of the 3rd toe was the first to touch the sand with a smaller attack angle to maximize the ground reaction force, but on solid ground, the lateral part was the first to touch the ground to minimize the transient loading. At push-off, the ostrich used solidification properties of granular sand under the compression of the 3rd toe to generate sufficient traction.
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Alexandrov, A. A., and V. V. Evstifeev. "Graph-Analytic Modification of the Method of Upper Estimation (Method of Energetic Geometry)." Key Engineering Materials 291-292 (August 2005): 637–42. http://dx.doi.org/10.4028/www.scientific.net/kem.291-292.637.
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Graph-analytic modification of the known method of upper estimation is presented here. This method gives possibility to get easily and quickly the result of graphic design of process and speed godograph (locus). The given modification allows realize graphic calculation of speeds and efforts of deformation through ratio l/h excluding design of speed godograph. This process does not only simplify and formalize all solutions but also gives possibility to optimize results and find defined parameters. Depending on the type of presented ratio l/h the given modification of this method attracts different kinds of graphic and analytic solutions. The results of calculation according to specific efforts coincide with known graph-analytic solution attained by the method of upper estimation with identical representation of the center of deformation. The usage of graphanalytic method in solution of energy expenses on the bases of geometric ratio allows find ways to the definition of conformity deformation processes applying to as forging as other fields of mechanics. The given method of defining energetic expenditure during the process of deformation gives the possibility of seeing interaction between some parts of deformed body, caused by selforganization of the process. Stating laws of self-organization of deforming processes is the necessary task of mechanic as a whole, mechanics of a solid deformed body and its appliances.
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Kirihara, Soshu, Katsuya Noritake, Satoko Tasaki, and Hiroya Abe. "Smart Processing of Solid Electrolyte Dendrites with Ordered Porous Structures for Fuel Cell Miniaturizations." Additional Conferences (Device Packaging, HiTEC, HiTEN, and CICMT) 2011, CICMT (September 1, 2011): 000017–22. http://dx.doi.org/10.4071/cicmt-2011-ta11.
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Solid electrolyte dendrites of yttria stabilized zirconia with spatially ordered porous structures were successfully fabricated for fuel cell miniaturizations by using micro patterning stereolithography. Micrometer order ceramic lattices with the coordination numbers 4, 6, 8 and 12 were propagated spatially in computer graphic space. Aspect ratios of the lattice diameters and lengths were designed between 1.0 and 2.0 to value the porosities in higher levels from 50 to 80 %. On the fabrication process, nanometer sized yttria stabilized zirconia were dispersed in to photo sensitive liquid resins at 30 % in volume fraction to obtain thixotropic slurries. The paste material was spread on a grass substrate with 10 μm in layer thickness by using mechanic knife edge movements, and an ultra violet micro pattern was exposed on the surface to create cross sectional solid layer with 2 μm in part accuracy. After the layer stacking process, the ceramic dispersed resin lattices of 100 μm in diameter were obtained exactly. These composite precursors were dewaxed and sintered at 600 and 1500 °C in an air atmosphere, respectively, and the fine ceramic lattices of 98 % in relative density were created. Gaseous fluid profiles and pressure distributions in the formed ceramic lattices with the various coordination numbers and porosity percents were visualized and analyzed by using finite element method. The fabricated solid electrolytes with the extremely high porosities and wide surface areas are expect to be applied to novel electrodes in the compact fuel cells. The smart processing of the solid electrolytes by utilizing computer aided design, manufacturing and evaluation methods will be demonstrated.
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Zhang, YL, and YM Zhang. "A new stochastic analysis method for mechanical components." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 227, no. 8 (November 23, 2012): 1818–29. http://dx.doi.org/10.1177/0954406212467735.
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Univariate dimension-reduction integration, maximum entropy principle, and finite element method are employed to present a computational procedure for estimating probability densities and distributions of stochastic responses of structures. The proposed procedure can be described as follows: 1. Choose input variables and corresponding distributions. 2. Calculate the integration points and perform finite element analysis. 3. Calculate the first four moments of structural responses by univariate dimension-reduction integration. 4. Estimate probability density function and cumulative distribution function of responses by maximum entropy principle. Numerical integration formulas are obtained for non-normal distributions. The non-normal input variables need not to be transformed into equivalent normal ones. Three numerical examples involving explicit performance functions and solid mechanic problems without explicit performance functions are used to illustrate the proposed procedure. Accuracy and efficiency of the proposed procedure are demonstrated by comparisons of the estimated probability density functions and cumulative distribution functions obtained by maximum entropy principle and Monte Carlo simulation.
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Ferreira, António, and Alireza Akhavan-Safar. "Editorial of the 1st Issue of Journal on Mechanics of Solids." Journal on Mechanics of Solids 1, no. 1 (November 11, 2022): 1–2. http://dx.doi.org/10.24840/2975-8262_001-001_001853.
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This is the first issue of the Journal on Mechanics of Solids (JMS). The journal is published by the University of Porto. JMS is an international, peer-reviewed, open access journal dedicated to publishing high-quality, cutting-edge research and review articles in various areas of solid mechanics that contribute to our understanding of the mechanics of solids and structures. JMS covers analytical, theoretical, experimental, and numerical studies that advance the practice of solid mechanics. The journal is expected to receive contributions from various areas of solid mechanics, including (but not limited to) biomechanics, contact mechanics, environmental influences, elasticity and plasticity, micro- and nanomechanics, fracture and damage mechanics, viscoelastic and viscoplastic materials, vibration and dynamics of solids and Structures, mechanics of composites and polymer materials. The scope of the journal also includes fatigue, impact, and creep of solids and structures. JMS also publishes articles on material characterization and mechanical behavior of engineered materials.
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Tang, Xiao Song, Jian Ping Xin, and Ying Ren Zheng. "Numerical Calculation of Micro-Plie in Slope Engineering." Applied Mechanics and Materials 644-650 (September 2014): 5113–20. http://dx.doi.org/10.4028/www.scientific.net/amm.644-650.5113.
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In order to conduct the numerical simulation of rock and soil slope strengthened by the micro-pile with reinforced bar, FEM strength reduction is combined with the program of FLAC which possesses the function of analyzing tensile and shear failure. The micro-pile is under plastic state due to its mechanic features. Solid element and ideal elastic-plastic constitutive model of Mohr-Coulomb are applied as the rock and soil mass and pile. The calculation model can work out the safety factor of slope, the dynamic changing process of pile deformation and failure, the failure mode of slope after strengthened by micro-pile. Then the structural element of pile is used to simulate piles, which can obtain the bending moment and shear force. The beam element is used to simulate the coupling beam. So the layout principle of inner force before the failure can be calculated.
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Zhang, Liang, Pengfei Li, Guanfeng Hu, Sufeng Zhang, Bin Hong, Haopeng Wang, Dawei Wang, and Markus Oeser. "Study on the Aging Resistance of Polyurethane Precursor Modified Bitumen and its Mechanism." Sustainability 13, no. 17 (August 24, 2021): 9520. http://dx.doi.org/10.3390/su13179520.
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As an environmentally friendly alternative for the production of high-performance modified asphalt by chemical reactions, a liquid-state polyurethane-precursor-based reactive modifier (PRM) was developed and employed in the asphalt modification. In contrast to the traditional solid bitumen modifier, for example, rubber and thermoplastic elastomers, the PRM as a liquid modifier has more significant advantages in reducing energy consumption and improving asphalt performance, which has attracted widespread attention. However, the aging resistance and its mechanism are not clear. In view of this, the aging performance of two PRM-modified bitumen (PRM-70 and PRM-90), under the short-term thermo-oxidative aging, long-term thermo-oxidative aging, and ultraviolet (UV) aging conditions, was investigated through chemical and mechanical methods. The results show that the PRM-90 is more susceptible to the thermos-oxidative aging and UV aging. The use of low-penetration-grade bitumen and ensuring an adequate reaction are beneficial to enhance the aging resistance of PRM-modified bitumen. The impact of aging on high-temperature performance of PRM-modified bitumen is great, followed by the low-temperature performance and the anti-fatigue performance. The mechanic-relevant rheological aging index (RAI) and fracture energy index (FEI) are recommended to evaluate aging properties for PRM-modified bitumen. This study not only provides support for further research on the relationship between the aging properties and mechanical performance of PRM-modified bitumen, but also provides a reference for conducting mechanism analysis.
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Guo, Hong Wei, Hong Zheng, and Wei Li. "Implement of Ameliorated ACM Element in Numerical Manifold Space for Tackling Kirchhoff Plate Bending Problems." Applied Mechanics and Materials 638-640 (September 2014): 1710–15. http://dx.doi.org/10.4028/www.scientific.net/amm.638-640.1710.
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Ab ridging the chasm between the prevalent ly employed continuum methods (e.g. FEM) and discontinuum methods (e.g. DDA) ,the numerical manifold (NNM) ,which utilizes two covers, namely the mathematical cover and physical cover , has evinced various advantages in solving solid mechanic al issues. The forth-order partial elliptic differential equation governing Kirchhoff plate bending makes it arduous to establish the -regular Lagrangian partition of unity ,nevertheless, this study renders a modified conforming ACM manifold element , irrespective of accreting its cover degrees, to resolve the fourth-order problems. In tandem with the forming of the finite element cover system that erected on r ectangular mesh es , a succession of n umerical manifold formulas are derived on grounds of the minimum potential energy principle and the displacement boundary conditions are executed by penalty function methods. The numerical example elucidates that , compared with the orthodox ACM element , the proposed methods bespeak the accuracy and precipitating convergence of the NMM .
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Bichara, Laura Cecilia, Hernán Enrique Lanús, Evelina Gloria Ferrer, Mónica Beatriz Gramajo, and Silvia Antonia Brandán. "Vibrational Study and Force Field of the Citric Acid Dimer Based on the SQM Methodology." Advances in Physical Chemistry 2011 (June 20, 2011): 1–10. http://dx.doi.org/10.1155/2011/347072.
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We have carried out a structural and vibrational theoretical study for the citric acid dimer. The Density Functional Theory (DFT) method with the B3LYP/6-31G∗ and B3LYP/6-311++ methods have been used to study its structure and vibrational properties. Then, in order to get a good assignment of the IR and Raman spectra in solid phase of dimer, the best fit possible between the calculated and recorded frequencies was carry out and the force fields were scaled using the Scaled Quantum Mechanic Force Field (SQMFF) methodology. An assignment of the observed spectral features is proposed. A band of medium intensity at 1242 together with a group of weak bands, previously not assigned to the monomer, was in this case assigned to the dimer. Furthermore, the analysis of the Natural Bond Orbitals (NBOs) and the topological properties of electronic charge density by employing Bader's Atoms in Molecules theory (AIM) for the dimer were carried out to study the charge transference interactions of the compound.
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Kecel, Serda, Aysen E. Ozel, Sevim Akyuz, and Sefa Celik. "Conformational analysis and vibrational spectroscopic investigation of L-alanyl-L-glutamine dipeptide." Spectroscopy 24, no. 3-4 (2010): 219–32. http://dx.doi.org/10.1155/2010/917414.
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In this study conformational behavior of anticancer chemotherapy dipeptide Ala-Gln and its dimers have been investigated by molecular mechanic and ab-initio calculations. The calculations on Ala-Gln dipeptide as a function of side chain torsion angles, enable us to determine their energetically preferred conformations. The relative positions of the side chain residues of the stable conformations of dipeptide were obtained, depending on the obtained conformational analysis results. The lowest energy conformation of the dipeptide has been determined by using the Ramachandran maps (Biopolymers6(1963), 1494;J. Mol. Biol.7(1963), 95) and compared with the quantum chemical ab-initio results. The geometry optimization, vibrational wavenumbers and intensity calculations of Ala-Gln dipeptide were carried out with theGaussian03program by using DFT with B3LYP functional and 6-31++G(d,p) basis set. The IR (4000–400 cm−1) and Raman spectra of the Ala-Gln dipeptide have been reported in solid phase, and compared with the theoretical vibrational data.
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Yi, Chengzhi, Xiaowei Zhang, Huixian Yan, and Bo Jin. "Finite Element Simulation and the Application of Amphoteric pH-sensitive Hydrogel." International Journal of Applied Mechanics 09, no. 05 (July 2017): 1750063. http://dx.doi.org/10.1142/s1758825117500636.
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Amphoteric hydrogels have been widely used in biologic and mechanic areas such as robot joints, biological cells, drug delivery systems. There are many factors that can influence the deformation of hydrogels, such as pH value, concentration of salt ions, solid constrains and external force, which all together makes the calculation very complicated. In this paper, an improved model for the calculation of amphoteric pH-sensitive hydrogels’ deformation is developed so that the behaviors of hydrogels in both acidic and alkaline solutions can be described quantitatively, and this model is implemented into finite element method (FEM) software ABAQUS in order to simulate hydrogel’s homogeneous and inhomogeneous deformations. The FEM results under free swelling state are compared with both analytical solution and FEM results existed before, and FEM results fit well with the experimental data. The buckling of amphoteric pH-sensitive hydrogel membrane is also analyzed, some natural phenomena, such as the wrinkling of human finger’s skin and the broad bean testa are successfully explained.
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Landschulze, Marcus, Rolf Mjelde, and Karin Landschulze. "Systematic simulation of multicomponent receiver coupling to the seafloor using rheological models." GEOPHYSICS 79, no. 6 (November 1, 2014): P9—P19. http://dx.doi.org/10.1190/geo2013-0329.1.
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This paper reports a comparison of three different rheological models used to characterize receiver coupling to the seafloor. We used a finite-element simulation tool to simulate the mechanical receiver coupling to the seafloor as a viscoelastic system with a combination of linear elastic springs and linear viscous dashpots, known as rheological models. Three models cover most of all mechanic coupling systems, the most commonly applied Kelvin-Voigt model (KVM), the Maxwell model (MM), and the standard linear solid (SLS) model. The models differ in behavior for different coupling aspects such as oscillation, creeping, stress relaxation, and their combinations. We tested these models’ ability and relevance for use in modeling seismic receiver coupling to the seafloor. For that purpose, we used an optimized mathematical approach to simulate coupling behavior under various coupling conditions. We found how receiver coupling will affect P- and S-waves for all three models and provided some insight into which model is most suitable to describe coupling under different circumstances. We found that the SLS model represents a general description of most of the coupling effects to the seafloor and should be used when the coupling acts as a viscoelastic system. The KVM and MM are applicable in extreme cases, such as for elastic waves in consolidated sediments (KVM) and dominant creeping effects, as in very soft biosediment (MM).
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Pelic, Marcin, Tomasz Bartkowiak, Stanisław Pabiszczak, Łukasz Macyszyn, and Roman Staniek. "Stand for measuring the volume of the blank using a laser sensor." Mechanik 91, no. 11 (November 12, 2018): 995–99. http://dx.doi.org/10.17814/mechanik.2018.11.179.
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The aim of the article is to present a method of measuring the volume of a blank using a laser sensor and a complete measuring stand. In the analyzed part of the manufacturing process of water fittings, the brass rod is cut on blanks of a given weight using CNC sawing machine. Due to the applied flashless forging technology, high cutting precision is required, understood as a relative mass tolerance of the blank of less than 0.1%. In this case, it becomes important to measure the geometry of the rod to calculate its volume – to correct the length of the blank. The natural way to calculate the volume of rotational solids with complex shapes is to determine the definite integral of the curve describing the outer surface of the solid. However, in the case of solids with geometrical errors this function may vary with the angle of rotation of the solid. In the case of real systems, in which the measurement results are a discrete sequence of numbers, it is natural to choose numerical integration. The paper presents the use of a laser sensor moved around the axis and along the rod to measure its volume and the concept of a complete measuring stand.
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Grillo, A., G. Y. Zingali, D. Y. Borrello, S. Z. Federico, W. Z. Herzog, and G. Giaquinta. "A multiscale description of growth and transport in biological tissues." Theoretical and Applied Mechanics 34, no. 1 (2007): 51–86. http://dx.doi.org/10.2298/tam0701051g.
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We study a growing biological tissue as an open biphasic mixture with mass exchange between phases. The solid phase is identified with the matrix of a porous medium, while the fluid phase is comprised of water, together with all the dissolved chemical substances coexisting in the pore space. We assume that chemical substances evolve according to transport mechanisms determined by kinematical and constitutive relations, and we propose to consider growth as a process able to influence transport by continuously varying the thermo-mechanic state of the tissue. By focusing on the case of anisotropic growth, we show that such an influence occurs through a continuous rearrangement of the tissue material symmetries. In order to illustrate this interaction, we restrict ourselves to diffusion-dominated transport, and we assume that the time-scales associated with growth and the transport process of interest are largely separated. This allows for performing an asymptotic analysis of the "field equations" of the system. In this framework, we provide a formal solution of the transport equation in terms of its associated Green's function, and we show how the macroscopic concentration of a given chemical substance is "modulated" by anisotropic growth. .
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Chernovol, M., M. Sviren, and R. Kisiliov. "Study of the process of preparing feeding mixtures using the composite mixer." Agricultural Science and Practice 5, no. 1 (April 15, 2018): 17–22. http://dx.doi.org/10.15407/agrisp5.01.017.
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Aim. Enhancing the quality and improving the technological process of mixing feeds using the new con- struction of the mixer and substantiating its rational parameters. Methods. Mathematical modeling theories, fundamentals of using machinery in animal breeding. Results. The estimated model of the functioning of a constructive-technological scheme of a composite mixer and the mathematical model of the dynamic interac- tion of mixer paddles and the solid mass of feeds were elaborated. It was established that the technological effi ciency of preparing the homogeneous mixture depends on physical and mechanic properties of its compo- nents, the impact and interaction between the form and geometric parameters of the attacking surface of the paddles, the slope angle, the setting increment and working modes of the mixer. Conclusions. The results of the studies confi rm the possibility of enhancing the effi ciency of the technology of preparing completely balanced feeding mixtures for cattle via the intensifi cation of the mixing process using the construction of the composite belt-paddle mixer, the elaboration of theoretical fundamentals of the interaction of feed components with the working bodies and substantiating their main constructive and technological parameters.
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Zhou, Jian, Ye-xun Li, Min-cai Jia, and Cui-na Li. "Numerical Simulation of Failure Behavior of Granular Debris Flows Based on Flume Model Tests." Scientific World Journal 2013 (2013): 1–10. http://dx.doi.org/10.1155/2013/603130.
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In this study, the failure behaviors of debris flows were studied by flume model tests with artificial rainfall and numerical simulations (PFC3D). Model tests revealed that grain sizes distribution had profound effects on failure mode, and the failure in slope of medium sand started with cracks at crest and took the form of retrogressive toe sliding failure. With the increase of fine particles in soil, the failure mode of the slopes changed to fluidized flow. The discrete element methodPFC3Dcan overcome the hypothesis of the traditional continuous medium mechanic and consider the simple characteristics of particle. Thus, a numerical simulations model considering liquid-solid coupled method has been developed to simulate the debris flow. Comparing the experimental results, the numerical simulation result indicated that the failure mode of the failure of medium sand slope was retrogressive toe sliding, and the failure of fine sand slope was fluidized sliding. The simulation result is consistent with the model test and theoretical analysis, and grain sizes distribution caused different failure behavior of granular debris flows. This research should be a guide to explore the theory of debris flow and to improve the prevention and reduction of debris flow.
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Winand, Lea, Stefanie Theisen, Stephan Lütz, Katrin Rosenthal, and Markus Nett. "Immobilization of the Amidohydrolase MxcM and Its Application for Biocatalytic Flow Synthesis of Pseudochelin A." Catalysts 13, no. 2 (January 18, 2023): 229. http://dx.doi.org/10.3390/catal13020229.
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The chemical synthesis of heterocycles typically requires elevated temperature and acid or base addition to form the desired product. Moreover, these reactions often involve hazardous reagents, which is why biocatalytic routes for heterocycle formation have gained increasing attention. In recent years, several enzymes belonging to the amidohydrolase superfamily have been identified to generate heterocycles via cyclocondensation reactions. Of particular interest is the amidohydrolase MxcM, which catalyzes the formation of an imidazoline moiety in the biosynthesis of the anti-inflammatory natural product pseudochelin A. In this study, we present a concept for the immobilization of this enzyme using a fused hexahistidine tag for fixation onto a solid, porous carrier. Notably, the immobilization improves the enzyme’s tolerance to organic solvents. The immobilized MxcM exhibits a residual activity of 169% in the polar solvent acetonitrile compared to the free enzyme, and the storage stability in the presence of 20 vol% acetonitrile was ameliorated. In addition, an immobilized enzyme reactor (IMER) was designed that can be operated under flow conditions. The MxcM-IMER retains its biocatalytic activity and mechanic stability over the tested operation time. These results provide important insights for the integration of heterocycle-forming amidohydrolases in chemical processes.
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Naimi-Jamal, M. R., and G. Kaupp. "Quantitative evaluation of nanoindents: Do we need more reliable mechanical parameters for the characterization of materials?" International Journal of Materials Research 96, no. 11 (November 1, 2005): 1226–36. http://dx.doi.org/10.1515/ijmr-2005-0214.
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Abstract Various sources of errors in the standard procedure according to the ISO 14577 draft for the iteration of elastic modulus and hardness of solid materials, with reference to fused quartz with its particular and unique indentation response, are pointed out on the basis of practical examples. Similar objections exist towards the use of the S 2 F N – 1 parameter, where S is the stiffness and F N is the normal force. It is suggested to use unambiguous mechanic characterization (at least additionally) by quantitative analysis of the loading curves in nanoindentations. These exhibit a general dependence between normal force and (displacement)3/2, the proportionality constant k being a non-iterated nanoindentation coefficient with dimension [force/length3/2] and unit [μN/nm3/2] that depends on the indenter tip geometry (pyramidal or conospherical) and is a characteristic material’s property. The validity has been demonstrated for virtually all types of materials (metals, semimetals, oxides, salts, organic molecular crystals, polymers) independent of their different bonding states. Pressure-induced phase transitions are detected by kinks in the linear plots for the loading curves well in the nanoindentation region. Crystalline materials, such as strontium titanate, exhibit far-reaching anisotropic effects along lattice axes that would strongly forbid the reference to an amorphous standard. The nanoindentation coefficient characterizes the different polymorphs and the face anisotropies. Another unambiguous mechanical characterization is given by the full work of indentation (as differentiated from the less secure plastic work of indentation). It also characterizes the face anisotropies with high precision for a given indenter as it is found proportional to (normal force)3/2, which allows for useful extrapolations.
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Auliya, Rahmat Zaki, Muhamad Ramdzan Buyong, Burhanuddin Yeop Majlis, Mohd Farhanulhakim Mohd. Razip Wee, and Poh Choon Ooi. "Characterization of embedded membrane in corrugated silicon microphones for high-frequency resonance applications." Microelectronics International 36, no. 4 (October 7, 2019): 137–42. http://dx.doi.org/10.1108/mi-02-2019-0010.
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Purpose The purpose of this paper is to propose an alternative approach to improve the performance of microelectromechanical systems (MEMSs) silicon (Si) condenser microphones in terms of operating frequency and sensitivity through the introduction of a secondary material with a contrast of mechanical properties in the corrugated membrane. Design/methodology/approach Finite element method from COMSOL is used to analyze the MEMS microphones performance consisting of solid mechanic, electrostatic and thermoviscous acoustic interfaces. Hence, the simulated results could described the physical mechanism of the MEMS microphones, especially in the case of microphones with complex geometry. A 2-D model was used to simplify computation by applying axis symmetry condition. Findings The simulation results have suggested that the operating frequency range of the microphone could be extended to be operated beyond 20 kHz in the audible frequency range. The data showed that the frequency resonance of the microphone using a corrugated Si membrane with SiC as the embedded membrane is increased up to 70 kHz compared with 63 kHz for the plane Si membrane, whereas the microphone’s sensitivity is slightly decreased to −79 from −76 dB. Furthermore, the frequency resonance of a corrugated membrane microphone could be improved from 26 to 70 kHz by embedding the SiC material. Last, the sensitivity and frequency resonance value of the microphones could be modified by adjusting the height of the embedded material. Originality/value Based on these theoretical results, the proposed modification highlighted the advantages of simultaneous modifications of frequency and sensitivity that could extend the applications of sound and acoustic detections in the ultrasonic spectrum with an acceptable performance compared with the typical state-of-the-art Si condenser microphones.
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ZHAO, NA, YUHONG CUI, XIAOYU WANG, ZHENZHEN ZHU, and LONG BAI. "3D NUMERICAL STUDY OF CELL DEFORMATION AND MIGRATION IN A FLOW CHAMBER." Journal of Mechanics in Medicine and Biology 15, no. 06 (December 2015): 1540048. http://dx.doi.org/10.1142/s0219519415400485.
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In recent years, the physiological phenomena of cell displacement and deformation in blood vessels have gradually become an important topic in the field of biomechanics, and also have important theoretical significance and application value in clinical medicine. To study the migration and deformation of blood cell, the influence of elastic modulus on its behavior, and the effect of deformation on its migration. A numerical simulation of a single cell displacement and deformation in a flow chamber was conducted in the present study using a computer program based on the fluid–solid coupling. The displacement and deformation of the cells with different elastic modulus as well as the influence of deformation on the movement of the cell were investigated. The results showed that the cell with greater elastic modulus had a smaller deformation in the direction of gravity and fluid velocity. The deformation of the cell had obvious effect on the displacement in the direction of gravity. The smaller the deformation of the cell in the direction of gravity was, the higher the cell could jump. The three-dimensional numerical calculation method adopted in this paper and the results obtained can provide a reference for the study of the cell mechanic behavior in the vessels.
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Huang, Zi Qiang. "Bistable Technology in Flat Panel Display: Principle and Progress." Key Engineering Materials 428-429 (January 2010): 206–11. http://dx.doi.org/10.4028/www.scientific.net/kem.428-429.206.
Full textAbstract:
Active matrices often related with high grade display devices, due to application of the storage elements, typically thin film transistor (TFT). Because of the complex procedures in the manufacturing TFT, investment of the high value manufacturing equipments and clarification plants is necessary, hence increasing the manufacturing cost of the flat panel, and more importantly, causing the pollution of water and air. As the contribution of TFT array merely exists in supplying storage function for the pixels of the display panel, large efforts have been made to find suitable cells that have bistable effect, so as to substitute the effect of TFT. As the bistable cell is just the storage pixel, one could construct a bistable cell to skip the needs of TFT active matrices. The paper is to introduce currently available bistable display devices in the following field: liquid crystal bistable displays with cholesteric liquid crystals, which is an example to introduce the bistable technology; iMod display devices based on mechanic induced bistable and light interference, which shows the possibility to construct bistable display; and the display based on solid powder movement in air or in vacuum, so called liquid powder displays, which shows how to improve the existed display.