bluuebunny/crossref_metadata_2025 huggingface dataset:
Searching for transmissible cancers among the mussels of Europe
Authors: Baez‐Ortega Adrian , Murchison Elizabeth P.
Published: December 2021

Transmissible cancers are infectious malignant cell clones that spread among individuals through transfer of living cancer cells. Several such clones have been identified in various species of marine bivalve molluscs, including mussels, clams and cockles. These parasitic cell lineages cause a leukaemia‐like disease called disseminated neoplasia, and are presumed to pass between hosts by ingestion of water‐borne cancer cells during filter feeding. Although occasional cases of transmissible cancer had previously been identified in mussels of the genus Mytilus in Europe, the number of distinct clones affecting these animals, and their prevalence, was unknown. In this issue of Molecular Ecology, Hammel et al. (2021) present findings from a large‐scale screen for transmissible cancer across 5907 European Mytilus mussels. Using a genotyping approach, Hammel et al. searched for signal of genetic chimerism, which can arise due to infection by transmissible cancer cells. The screen detected a previously identified globally distributed mussel transmissible cancer at very low prevalence, and found no evidence of additional contagious clones. A parallel histological screen additionally revealed low prevalence of a nontransmissible form of disseminated neoplasia. By quantifying the burden of disseminated neoplasia in European mussel populations, this study provides strong foundations for future work investigating the origins, evolution and impacts of transmissible cancers in mussels.
High‐fat diet‐induced metabolic syndrome increases ligature‐induced alveolar bone loss in mice
Authors: Lu Zhongyang , Li Yanchun , Yu Hong , Lopes‐Virella Maria F. , Huang Yan
Published: December 2021

Background

It has been well documented that metabolic syndrome (MetS) increases severity of periodontitis. In this study, we determined the effect of high‐fat diet (HFD)‐induced MetS on alveolar bone loss in a mouse model with ligature‐induced periodontitis. To understand how MetS increases bone loss, we tested our hypothesis that palmitic acid (PA), a most abundant saturated fatty acid in the HFD, interacts with lipopolysaccharide (LPS) to promote osteoclastogenesis.

Methods

We induced MetS by feeding mice HFD for 18 weeks and induced periodontitis with ligature placement. After treatments, we assessed alveolar bone loss using micro‐computed tomography and determined osteoclastogenesis using tartrate‐resistant acid phosphatase (TRAP) staining. To explore the mechanisms, we treated macrophages with PA, LPS or both and analyzed the osteoclast formation and cytokine expression in macrophages.

Results

While ligature robustly induced periodontitis in mice with or without MetS, the mice with MetS had more bone loss than those without MetS. PA and LPS cooperatively induced osteoclast formation and stimulated the expression of inflammatory cytokines involved in osteoclastogenesis potentially via a FAT/CD36‐dependent mechanism in macrophages.

Conclusions

HFD‐induced MetS increases alveolar bone loss in mice with ligature‐induced periodontitis, and PA and LPS cooperatively stimulate osteoclast formation and proinflammatory gene expression in macrophages.
A new orogenic gold belt in Southeast Asia: Geology, mineralogy and genesis of the Vangtat gold deposit, Southeastern Laos
Authors: Bounliyong Patthana , Arribas Antonio , Watanabe Yasushi , Echigo Takuya , Wong Henry
Published: December 2021

The Vangtat deposit is the major gold deposit in a new orogenic gold belt discovered and developed in southeastern Laos in the past two decades. Our study of the Vangtat orogenic gold deposit shows that it formed within a convergent margin along the western segment of the Poko suture zone, which marks the collision between the Indochina Terrane and the Kontum Massif. Shear structure and greenschist facies metamorphic rocks are the main hosts for gold mineralization in the Vangtat deposit. High‐grade gold‐bearing quartz‐sulfide veins and wall rock hydrothermal alteration are genetically related, and alteration minerals consist of quartz, carbonate, graphite, white mica, chlorite, and pyrite. The study of fluid inclusions and wall rock alteration assemblages indicate that the Vangtat gold deposit was formed by an aqueous‐carbonic, low salinity, reduced, weakly alkaline to near‐neutral pH fluid, mainly composed of H2O, NaCl, CO2, CH4, N2, H2S, H2, O2, Si, and K. Gold was predominantly carried as a sulfide complex. The precipitation of gold is related to wall rock sulfidation and the further reduction with the carbon‐bearing host rock. The correlation between trapping temperature obtained from arsenopyrite geothermometry (360–395°C) and homogenization temperature obtained from primary fluid inclusion microthermometry (240–250°C), indicates a pressure and depth range for the Vangtat deposit of 380–420 MPa and 11–13 km, respectively. Gold appears as inclusions mainly in pyrite, and auriferous pyrite is homogeneous in textural, chemical, and sulfur isotopic composition. Auriferous pyrite δ34S values range from +4 to +6‰, which is compatible with the δ34S composition of igneous rocks. Together with cobalt/nickel ratios from the Vangtat auriferous pyrite, which are significantly greater than one (avg. 6.3), we suggest that mafic‐ultramafic rocks in the geologic basement of the Vangtat deposit are the plausible source of hydrothermal gold and sulfur. The formation of this orogenic gold deposit is associated with metamorphic dehydration and devolatilization that transported gold to the site of deposition.
Complex iron and sulphate reducing Cretaceous sedimentary system revealed by extreme isotope values
Authors: Gyomlai Thomas , Fayek Mostafa , Ferrini Vincenzo , Mignardi Silvano , De Vito Caterina
Published: December 2021

The iron and sulphur isotope compositions of sedimentary pyrites have been extensively used as a proxy for microbial metabolisms and redox evolution of the oceans. We illustrate the benefit of in‐situ and coupled study of Fe and S isotopes on sedimentary pyrites from late mid‐Cretaceous sediments from the Central Apennines, Italy. We report extremely low δ56Fe values for sedimentary pyrites (as low as −4.7‰) and unusual high δ34S values (as high as +88.9‰). We propose a model that explains these extreme values but also the large range of pyrite δ34S and δ56Fe values as well as the considerable microscale variations in this values. These isotopic compositions were likely produced by microbial dissimilatory iron reduction in the shelf sediment, transportation of Fe2+ via an iron shuttle, production of heavy SO4 by pyrite precipitation in the water column, diffusion and advection of SO4 and H2S, and finally bacterial sulphate reduction.
Motivasi dan Halangan Bagi Pelajar Asing Menguasai Bahasa Melayu Melalui Pembelajaran Secara dalam Talian di Universiti Teknologi Malaysia
Authors: Ma’alip Halimah , Zakaria Khuzaiton , Che Roza Che Hazira , Zulkipli Nurul Adila
Published: December 2021

Kajian ini dijalankan untuk mengenal pasti tahap motivasi pelajar asing dalam menguasai bahasa Melayu secara pembelajaran dalam talian. Selain itu, kajian ini juga menghuraikan halangan yang mempengaruhi mereka dalam menguasai bahasa Melayu melalui pembelajaran dalam talian. Kaedah kuantitatif dan instument soal selidik telah digunakan bagi memperoleh data kajian ini. Sebanyak 227 orang responden dipilih merupakan pelajar asing yang mengambil Kursus Bahasa Melayu Komunikasi dari pelbagai negara. Data dianalisis dan dipaparkan dalam bentuk min, sisihan piawai dan tahap interprestasi. Dapatan kajian ini mendapati bahawa min keseluruhan bagi tahap motivasi pelajar asing dalam menguasai bahasa Melayu secara dalam talian ialah tinggi. Hal ini membuktikan bahawa pelajar asing ini masih bersemangat untuk menguasai bahasa Melayu walaupun pembelajaran dijalankan secara dalam talian. Min keseluruhan bagi halangan pelajar asing menguasai bahasa Melayu ialah sederhana dan membuktikan bahawa halangan ini hanya dihadapi oleh segelintir pelajar sahaja. Sikap pelajar yang bermotivasi tinggi mampu mengatasi setiap halangan. Pelajar perlu menyesuaikan diri pada musim pandemik ini dan menggunakan peluang ini untuk meningkatkan pengetahuan dalam pembelajaran dan pengajaran secara dalam talian.
Challenges in Implementing the CEFR in English Language Classrooms
Authors: Mohammed Nur Athirah , Abdul Raof Abdul Halim , Md Yusof Masdinah Alauyah
Published: December 2021

The adoption of the Common European Framework of Reference for Languages (CEFR) in the English Language Education Roadmap 2015-2025 is a reform effort to enhance the standard of our students’ English language proficiency level. While it is a commendable initiative, its implementation in schools has received mixed reactions especially from teachers who are confronted with a number of challenges. Hence, this study was carried out to investigate the nature of challenges encountered by English language teachers in implementing the CEFR in their classrooms. Data for this study were collected from questionnaires gathered from 117 English language teachers in primary schools in Johor Bahru district. The findings revealed the challenges were related to teachers’ English language proficiency level, designing class activities, students’ participation in class, the textbooks used, teachers’ workload, and students’ proficiency level. The challenges were found to be inter-related and could be traced to lack of CEFR-related training, insufficient teaching and learning materials, constraint of time, and the policy which does not allow for students to be streamed based on their proficiency level. All this seemed to make it more difficult for the teachers to implement the CEFR successfully.
An Extension of Two Species Lotka-Volterra Competition Model
Authors: Ba Idy , Ndiaye Papa Ibrahima , Ndao Mahe , Diakhaby Aboubakary
Published: December 2021

Limiting resource is a angular stone of the interactions between species in ecosystems such as competition, prey-predators and food chain systems. In this paper, we propose a planar system as an extension of Lotka-Volterra competition model. This describes two competitive species for a single resource which are affected by intra and inter-specific interference. We give its complete analysis for the existence and local stability of all equlibria and some conditions of global stability. The model exhibits a rich set of behaviors with a multiplicity of coexistence equilibria, bi-stability, tri-stability and occurrence of global stability of the exclusion of one species and the coexistence equilibrium. The asymptotic behavior and the number of coexistence equilibria are shown by a saddle-node bifurcation of the level of resource under conditions on competitive effects relatively to associated growth rate per unit of resource. Moreover, we determine the competition outcome in the situations of Balanced and Unbalanced intra-inter species competition effects. Finally, we illustrate results by numerical simulations.
Inter-Process Communication for Force Display of Dynamic Virtual World
Authors: Hasegawa Shoichi , Ishii Masahiro , Koike Yasuharu , Sato Makoto
Published: December 2021

This paper proposes a novel inter-process communication, between a virtual world manager with slow update rate and a haptic controller with fast update rate, which incorporates the integrated force given from the user to the world. High-speed refresh rate, generally 1kHz, is required to present, stiff virtual objects that, have spring-damper characteristic with haptic display. On the other hand, the managing of an interactive and rich virtual world that takes a lot of computational time makes the refresh rate as low as 10Hz, which is enough for perceptual cycle.

The dividing of the process into two has been proposed to interact with such a world and inter-process communication between the processes has been discussed. Although the methods proposed previously work well on condition that the virtual world is static, goes wrong on dynamic world.

The importance of the force integration on the object, motion acquisition is described and an inter-process communication that cares about the force integration is proposed to remove the influence of the sampling timing. An experimental result shows that the proposed method improve the accuracy of the operation.
Cancellation of Feedthrough Dynamics Using a Force-Reflecting Joystick
Authors: Gillespie R. Brent , Hasser Christopher , Tang Philip
Published: December 2021

This paper reports on a set of theoretical and experimental investigations into the use of force reflection to enhance the dynamic behavior of human piloted vehicles, especially joystick-controlled vehicles such as fly-by-wire jets, bulldozers, and powered wheelchairs. Briefly, force reflection is used in the manual controls to cancel the effects of feedthrough dynamics. Feed-through dynamics refers to generation of inadvertent steering or speed command inputs due to the action of inertia forces between the pilot’s hand and manual controls. These inertia forces arise in the pilot’s body in response to vehicle accelerations. To eliminate feedthrough dynamics, a canceling force is produced on the force-reflecting joystick using a model of the pilot dynamics and the known vehicle accelerations. A custom motion platform and a commercial force-reflecting joystick are used in a set of experiments to test the idea. Parameter values for an assumed model are estimated by observing the response of the pilot’s body to known platform accelerations. Cancellation of feedthrough dynamics is demonstrated for a human subject.
A Framework of Using NURBS Curve as the Membership Functions in the Neural-Fuzzy System
Authors: Luo Tao , Lu Wen F.
Published: December 2021

A novel neural-fuzzy system is developed by using the NURBS (Non-uniform Rational B-spline) curve as the membership functions in this paper. The neural-fuzzy system uses the fuzzy logic rule to estimate the output of the systems and uses the weight updating method in neural networks to adjust the rules. The NURBS interpolation method is proposed to construct adaptable membership functions for the proposed neural-fuzzy system. Since the shape of a NURBS curve is controlled by adjusting the control vertices and their weights, changing a control vertex and its weight will only affect the curve shape locally. This local control property reduces the number of iterations of learning in the system. Due to the adaptability of the NURBS membership function, the proposed system will need fewer fuzzy rules compared to existing systems but result in faster error convergence and better accuracy in system identification. The simulation results in Test Examples show that the presented NURBS neural-fuzzy system can identify complex systems with good accuracy and fast learning speed.
Analyses of Frame Problems by DQEM Using EDQ
Authors: Chen Chang-New
Published: December 2021

The differential quadrature element method (DQEM) and the extended differential quadrature (EDQ) have been proposed by the author. The EDQ is used to the differential quadrature element analysis of the frame problems. The element can be a nonprismatic beam. The EDQ technique is used to discretize the element-based governing differential equations, the transition conditions at joints and the boundary conditions on domain boundaries. An overall algebraic system can be obtained by assembling all of the discretized equations. A numerically rigorous solution can be obtained by solving the global algebraic system. Mathematical formulations for the EDQ-based DQEM frame analysis are carried out. By using this DQEM model, accurate results of frame problems can efficiently be obtained. Numerical results demonstrate this DQEM model.
Experimental Non-Linear Dynamics of a Shape Memory Alloy Wire Bundle Actuator
Authors: Mosley Michael J. , Mavroidis Constantinos
Published: December 2021

In this paper, the non-linear dynamics of a new Shape Memory Alloy (SMA) actuator that possesses impressive payload lifting capabilities are presented. This actuator consists of 48 SMA wires mechanically bundled in parallel forming one powerful muscle. It was designed to lift up to 100 lbs., which is approximately 300 times its weight. This SMA actuator was tested in open loop experiments with different loads and different inputs, such as step, ramp, sinusoid, and half sinusoid, and its dynamic characteristics were evaluated. An important observation made during the dynamic analysis was the unpredictability of the actuator’s response when low to moderate voltages are applied. This characteristic strongly suggests chaotic behavior of the actuator, which could potentially cause control difficulties in fine and high accuracy tasks. An investigation into chaos was conducted using time histories, phase plots, and Poincaré maps. As shown in the diagrams presented in this paper, system response to larger input voltages is periodic, whereas lower input voltages produce responses that strongly indicate chaotic behavior.
An Optimization Based Approach for Determining Whether a Set of Elementary Contacts Is Geometrically Feasible
Authors: Goeree Barry B. , Fasse Ernest D. , Marefat Michael M.
Published: December 2021

The contact between two polyhedral objects can be represented with a set of elementary contacts — surface-vertex and edge-edge contacts. However, not all possible contact representations are geometrically possible. An equivalent optimization problem is posed to verify geometric feasibility. A steepest descent algorithm has been implemented and applied to two test cases — one feasible and one infeasible contact representation. The results of this work can be used to implement a predicate that verifies whether a contact representation is geometrically possible. The predicate can be used in a generate-and-test paradigm to synthesize the entire contact space.
Micromagnetic In-Process Surface Integrity Analysis of Ground Workpieces
Authors: Tönshoff H. K. , Mandrysch T.
Published: December 2021

In production engineering, especially in grinding processes, the thermal damage has a significant influence on the quality and thus on the reliability of heavy loaded components. Therefore different micromagnetic sensor systems for the nondestructive detection of residual stresses, surface hardness, depth of hardness and partly for the avoidance of grinding burn have been developed. The current research concentrates on a continuous inspection of the quantities mentioned to enable a so-called in-process inspection as well as a 100% quality documentation during, before and after the machining process. No further additional post-process measurements are necessary.
Experimental Study of Virtual Tools With Attributes
Authors: Kesavadas T. , Subramaniam Hari
Published: December 2021

Use of synthetic and surrogate tools in training robots and planning events within virtual environments has tremendous potential in making programming of complex machines simple and easy. In our research we have experimented the use of attribute laden virtual tools in various tasks such as robotic-based grinding and welding processes. Such attribute laden virtual tools aid human operators in path planning as well as in making decisions about the process itself. In this paper we have tested our concepts of virtual tools and the use of attributes such as physical, reflex and command actions. Four sets of experiments were conducted with human subjects. Two kinds of virtual tools were used in these experiments, one with guide plane attributes and the other without them. One set of experiment tested human performance using the head mounted display interface and the effect of learning process in using the virtual tool. Results showed that there was marked improvement in task execution time using the tools laden with guide plane attributes over the unencumbered virtual tools. This paper discusses various future applications of these virtual tools in manufacturing. It is observed that unlike non-haptic visual interfaces, where no physical feed back is available to the user, attribute laden tools can provide a much easier interface to robots.
Dynamic Stability Analysis of Spur Gears in a Steady State
Authors: Oh Sejoong , Grosh Karl , Barber James R.
Published: December 2021

In the previous work by the authors (Oh et al. (1998)), it was shown that in order for the model of an interacting spur gear pair to conserve energy, the dependence of the mesh stiffness on the mean rotation must be included in deriving the equations of motion. A quadratic nonlinearity arises from the dependence of the mesh stiffness on the mean rotation, even under the assumption of small deflection. This nonlinearity ensures conservation of energy. In this study, the stability of the steady-state response of interacting spur gears, both for the new equation of motion (EOM) and the classical EOM, is investigated. The map for periodic orbits is determined and a linearized stability analysis is performed. Once the stability is determined, the comparison between the classical and the new EOM is made for a primary, a secondary sub-harmonic, and super-harmonic resonances. The frequency-amplitude curve from direct simulation is compared to the stability analysis. The effect on the stability by the nonlinear jump term is shown, as well as by the variable time. The effect of damping and the magnitude of the applied torque on the stability is shown.
Optimization of an Automotive Structure Subject to Harmonic Excitation
Authors: Garcia Arnoldo , Lumsdaine Arnold , Yao Ying
Published: December 2021

Optimization theory has been used to obtain solutions to a variety of engineering problems involving beam vibration. In this study, the objective is to design a structure that uses the minimum amount of material. The structure examined is a beam undergoing coupled bending and torsion, as is common in automotive structure beams.

The objective of this study is to minimize the weight of an automotive structure subject to harmonic excitation. The automotive structure is modeled with beam elements in I-DEAS, a computer-aided engineering and finite element software. For each given length, its cross-sectional area is optimized by a discrete finite element method.

In addition, a bracket was modeled in conjunction with the automotive structure. Although the optimal design of beams undergoing forced harmonic loading is available in the literature, to the authors’ knowledge, optimal design of such structures including an intermediate support have not been considered. The placement of the bracket was also treated as a design parameter by varying its location and size in the optimization process. Results show that the total mass after optimization had a mass reduction of 91% when compared to the original weight.
Acoustic Radiation From Mild Steel Plates of Various Thicknesses and Aspect Ratios Excited by a 120 Tonne Press
Authors: Eager David B. M.
Published: December 2021

The critical frequencies for 3, 4 and 5 mm thick flat rectangular mild steel plates of surface areas varying from 0.3 to 3.0 m2 were obtained experimentally using a 120 tonne expanded-metal press. The critical frequencies were noted to increase with decreasing plate thickness and constant for varying perimeter and surface area. The measured values of the critical frequency compared closely with published theoretical data for similar plate parameters.
Modeling and Imaging Flexural Plate Wave Devices
Authors: Adkins D. R. , Schubert W. K. , Butler M. A. , Chu A. S.
Published: December 2021

Sandia National Laboratories is developing a new form of flexural plate wave device (FPW) for sensor applications. In this device, Lorentz forces cause out of plane vibrations in a silicon nitride membrane. Current induced in transducer lines on the membrane provides information about the amplitude and phase of these surface vibrations. By tracking the large amplitude vibrations that occur at resonant frequencies, it is possible to infer information about loading on the membrane. In fabricating FPWs, it is important to understand the impact that minor defects can have on operation. Through modeling and testing, we are developing resilient designs that provide large amplitude signals with a high tolerance to defects. A finite element model has been developed to perform design trade-off studies, and results from the model are being verified with a unique measurement system that can image Angstrom scale displacements at vibrational frequencies up to 800 kHz. Results from FPW modeling and imaging efforts are presented in this paper.
Sputtered Silicon for Microstructures and Microcavities
Authors: Honer Kenneth A. , Kovacs Gregory T. A.
Published: December 2021

Sputtered silicon can be used to make released microstructures at temperatures compatible with prefabricated aluminum-metallized CMOS circuitry. The fabrication sequence is similar to LPCVD polysilicon processes and involves a wet release from an oxide sacrificial layer. This process was used to fabricate a variety of test structures, including cantilevers, combs, and spirals. During release of the structures porosity to HF was observed in films up to 5 μm thick. This porosity resulted in the formation of completely enclosed cavities formed beneath silicon membranes over oxide sacrificial layers, and may have implications for the packaging of released devices. Several properties of the sputtered silicon films were investigated, including their in-plane stress, strain gradient, film density, surface roughness, electrical resistivity, and permeability. The dependency of these properties on deposition power, pressure, and film thickness as well as the effects of low-temperature annealing were also investigated.
Optical Vibration and Acceleration Sensor With a Silicon Cantilever
Authors: Kimura Mitsuteru , Toshima Katsuhisa , Satoh Harunobu
Published: December 2021

A new type all optical vibration and acceleration sensor using the combination of micromachined Si cantilever and optical fiber is proposed, and its fundamental characteristics are demonstrated. The light emitted from bulb-lens set into the V-groove is reflected at the reflector formed on the Si cantilever and then recoupled into the bulb-lens. Several sensors with different length (0.64–6.0 mm long) of the Si cantilever are fabricated to compare the theoretical resonance frequency fr obtained from the simple model and experimental ones. They had good agreement. From the sensing principle the sensing frequency range of the vibration is suitable below the fr of the Si cantilever of the sensor.
Extensive Experimental Study on Diaphragm-Based Piezoelectric Microphone
Authors: Niu Meng-Nian , Zeng Hong , Yan Hai , Kim Eun Sok
Published: December 2021

This paper reports our extensive experimental study on diaphragm-based piezoelectric microphones fabricated on a silicon substrate. We have fabricated and carefully analyzed about 60 micromachined piezoelectric microphones (composed of piezoelectric ZnO film, insulating layers and electrodes) built on a low-stress silicon nitride diaphragm (with and without corrugation on the diaphragm and with five kinds of residual stress in the diaphragm). Microphone sensitivity is measured in an acoustic chamber with a B&K4135 microphone. Vertical displacement of a microphone diaphragm under an applied acoustic pressure is measured with a focused-beam laser Doppler displacement meter. Our results show that (1) corrugation releases both tensile stress and compressive stress effectively, and increases the center displacement greatly, (2) a good bending curvature in the active area is needed for a good microphone sensitivity, and (3) ZnO structural integrity is the major factor that affects the bending curvature in the active area.
Partly Disposable Switching and Injection Microvalves for Medical Applications
Authors: Sato Hironobu , Shoji Shuichi , Kim Eipin , Miura Keisuke
Published: December 2021

Two types of one-inlet and four-outlets pneumatic microvalves for medical applications were fabricated and evaluated. Since the microvalves consist of a separable actuator part and a channel part, the channel part in which the sample liquid are introduced can be partly disposed. Both parts were fabricated using Si and polymer membrane. Two types of polymer membranes of silicone rubber and new cyclized perfluoro polymer (CPFP) were utilized in different types of microvalves for controlling high viscosity and low viscosity samples. In the case of the switching valve using silicone membrane, leakage was less than 0.01 μl/min (inlet pressure of 1mH2O) and the maximum open/closed flow ratio is larger than 105. These microvalves are useful in parallel and multi sensing systems. To achieve the monitoring the pneumatic actuation, integration of piezoresistive pressure sensors on the actuator part was also carried out.
An Integrated Reservoir for On-Chip Aqueous Storage in Microfluidic Systems
Authors: Patel Manoj , Henderson H. Thurman , Bhansali Shekhar , Ahn Chong H.
Published: December 2021

A reservoir for a silicon-based “lab-on-a-chip” integrated microfluidic system has been designed, fabricated and initially characterized. The reservoirs are necessary for storing reagents, antibodies and buffers required for on-chip capture of target microorganisms in this work. Aside from the matter of storing fluids and providing a pressure head for flow or flow augmentation one has the issue of biochemical compatibility of the contact surface. Where one does not desire a pressure head, a mere bio-chemically compatible “collapsible” bag is desired. All these factors are included in the device. This paper reports design issues, fabrication, packaging and initial characterization of the reservoirs. Scaling possibilities are essentially unlimited, however in this case standard reservoirs have been developed in modules of 1/8 and 1 ml capacity.
Coupled Electrostatics-Structures-Fluidic Simulations of a Bead Mesopump
Authors: Athavale M. M. , Li H. Y. , Yang H. Q. , Przekwas A. J. , Cabuz C. , Herb W.
Published: December 2021

A novel microfluidic pump called bead mesopump was analyzed using numerical tools for performance predictions. An electrostatically actuated diaphragm produces pumping action, with appropriately placed inlet and outlet channels for flow rectification. For the first time ever, coupled, transient electrostatics-structures-flow simulations were successfully performed on this complex problem. Simulation data compare well with the available experimental test data. Simulations clearly show the presence of squeeze film flow, and its effects on actuation times and voltages. Simulations of different chamber and electrode designs were also completed to assess effects on pump performance. Numerical simulation tools for MEMS are thus shown to be of significant use in future for analysis of new pump designs, and device optimization.
Micro-Channels With Suspended Temperature Sensors for Heat Transfer Study
Authors: Jiang Linan , Wang Yuelin , Wong Man , Zohar Yitshak
Published: December 2021

A micro-system consisting of micro-channels with integrated temperature sensors was successfully designed and fabricated for the study of heat-transfer properties of fluid flow in micro-domains. Surface micro-machining technology was used to construct the micro-channels with dimensions of about 40μm × 1.4μm × 4000μm. Polysilicon thermistors, 4μm × 4μm × 0.4μm in size were suspended across the channels and directly exposed to the fluid for local temperature measurements. The micro-channels and the micro-sensors were calibrated prior to the heat-transfer studies. Experimental results of temperature distributions along a micro-channel are presented. The integrated micro-system performance was analyzed to provide a framework for the interpretation of the experimental data, and the various heat-transfer mechanisms are subsequently discussed.
In Situ Dynamics of Concentrated DNA Molecules in a Shear Flow
Authors: LeDuc Philip , Pfister Bryan , Xu Yangqing , Wirtz Denis , Bao Gang
Published: December 2021

Polymer dynamics has been studied for many years because of its importance in many areas including materials, mechanics, biology, and medicine (Munk, 1989; Hoffman, et al., 1984). The dynamics of macromolecules in shear flow has been studied using light scattering and birefringence, but the effect of shear on the dynamics of individual polymers is not well understood (Doi & Edwards, 1986; de Gennes, 1991; de Gennes, 1997). Recently we studied the conformational changes of DNA molecules under shear in dilute concentration (LeDuc et al., 1998). Here we report the observations of the dynamics of fluorescently-labeled DNA molecules in a shear flow with increased concentration. Under a controlled shear flow, these flexible polymers exhibit various extended conformations, which range from parallel to perpendicular in orientation when compared to the flow direction. The amount of stretching that occurs in these experiments is found to be less than that for the dilute concentrations of the DNA solutions. Further, the stretching of the molecular solutions is found even at shear rates much smaller than the inverse of the relaxation time of the molecule. The in situ observations also reveal the effect of polymer concentration on the entanglement of macromolecules. These results provide insight into the behavior of individual and concentrated polymer molecules under shear and help further development of models for polymer dynamics (Perkins, et al., 1994; Smith, et al., 1992; Wirtz, 1995).
Panel Discussion: Fluid Mechanics Issues in Pulmonary Airways
Authors: Evrensel Cahit A. , Krumpe Peter E. , Olson Dan E. , Hammersley Jeffrey R.
Published: December 2021

Slowly travelling mucous, 2.4–5.5 mm/min, propelled by the beating action of cilia, is the main system to clear foreign substances from the pulmonary airways (Foster et al., 1980; Yeates, et al., 1981). Increased volume of mucous production and decreased mucociliary clearance may cause accumulation of mucous in the airway tree (Kim, 1997). Degree of airway obstruction due to access mucous and the effectiveness of the mucociliary clearance depends on rheology and quantity of mucous as well as activity of the cilia (King, 1998, Kim et al., 1997). The mucociliary system is complex and carefully regulated so as to maintain an optimal thickness of the serous fluid to facilitate the engagement of the beating cilia with the mucous layer (Yoneda et al., 1976). The depth of the serous layer is regulated by microtubules in the ciliated epithelial cell surfaces (Basbaum and Finkbeiner, 1990). The mucous layer apparently floats on its surface, either as a continuous sheet of overlapping layers and fibrous networks (Sturgess, 1977), or as a series of islands (Van As and Webster, 1974).
The Effects of Implantation Techniques and Vortex Shedding on Free Emboli Formation in Mechanical Heart Valves
Authors: Li Yanmei , Bluestein Danny
Published: December 2021

A numerical analysis of pulsatile turbulent flow was conducted past a St. Jude Medical MHV in the aortic position, to study the effects of valve implantation technique on the thromboembolic potential of the valve. The simulation focussed on the assumption that by altering the flow fields past the valves, the valve orientation and the suturing technique employed have a favorable or undesirable effect on the thromboembolic potential of the valve. It was demonstrated that the combination of a valve that is not aligned with the axis of the blood flow and subannularly sutured pledgets, produced accelerating jet flow through the valve orifices and a wider wake of periodic shed vortices in the valve’s leaflets wake. The existence of the shed vortices was confirmed by Digital Particle Image Velocimetry (DPIV). measurements. Platelets paths that exposed the platelets to the highest shear levels led them to entrapment within the shed vortices, indicating that the risk of cardioembolism will be enhance.
Cyclic and Residual Stresses Generated in the UHMWPE Component of Total Knee Replacements During the Walking Cycle
Authors: Natarajan Raghu N.
Published: December 2021

Fatigue due to cyclic stresses is one of the predominant failure modes seen in retrieved tibial polyethylene components. There is no clear understanding of the influence of knee kinematics on wear seen in retrieved samples. Magnitude, direction and location of the contact load at the tibial surface were taken from the measurement obtained from gait analysis of a patient with a total knee replacement and was input into a three dimensional finite element model of a tibial component. The analyses showed that stress fluctuations and stress reversals occur both on the surface and just below the surface in the posterior region of the component. Residual stresses were produced due to plastic deformation in the posterior contact region of the component.
Experimental and Finite Element Comparaison of Various Joint Fixation Designs
Authors: Patenaude O. , Shirazi-Adl A. , Dammak M.
Published: December 2021

The short- and long-term success of tibial cementless implants depends on the initial fixation stability provided primarily by posts and screws. Excessive relative motions at the bone-implant interface are known to inhibit bone ingrowth and, hence, biologic fixation. In this work, the performance of a number of fixation configurations under static and fatigue combined loads (i.e., compression plus shear) is investigated both experimentally and numerically. These results will permit both to compare different fixation types and to serve to validate a 3D finite element model that incorporates the measured nonlinear bone-implant friction and posts/screws pull-out tests. Once validated, the finite element model is also used to study the effect of different bone-implant friction models for porous coated posts and plate and of loading order of application on predictions.
On a Refined Finite Element Model of the Knee Joint
Authors: Moglo K. , Shirazi-Adl A.
Published: December 2021

A refined 3D elastostatic nonlinear finite element model was developed for the human knee joint in other to predict the passive global primary/coupled response and force transmission mechanism under various loads/movements and pathologic conditions. The joint geometry was based on an existing model (Bendjaballah et al., 1995) which was substantially refined in the articular cartilage and menisci regions as well as the articulating contact surfaces. The articular cartilage is subdivided into two layers along the depth allowing for the possibility to consider non homogeneity in mechanical propreties. The incremental response of the knee joint was evaluated under axial force of up to 780 N applied on the femur in full extension position. The global primary/coupled response, ligament forces as well as load transmission in medial/lateral plateaus through menisci and uncovered cartilage are analysed.
A One-Dimensional Approach to Viscoelastic Material Stiffness Calculations
Authors: Mayrose James , Kesavadas T. , Narayanasamy Senthil K.
Published: December 2021

Accurate models of human body tissues and organs have tremendous applications in the medical field. Modeled organs within virtual environments are increasingly being used as research tools in medicine. In the near future, these research tools will make their way into teaching and clinical practice. These virtual environment simulations allow researchers to study the behavior of human organs and to develop large databases of organ characteristics. The 3D viewing and interaction available through virtual reality make it possible for physicians to practice many medical procedures without ever touching a patient. The main goal of this study is to evaluate the effectiveness of a “sensory data glove”, developed by the authors, for calculating the stiffness of an object beneath a surface of varying stiffness.
The Annual National Science Foundation Publication on Senior Design Projects to Aid Persons With Disabilities
Authors: Enderle John D.
Published: December 2021

An annual publication on senior design projects to aid persons with disabilities supported by the National Science Foundation since 1988 is described in this report Some of the projects described in these books are custom modifications of existing devices, modifications that would be prohibitively expensive to the disabled individual were it not for the student engineer and this NSF program. Other projects are unique one-of-a kind devices wholly designed and constructed by the student for the disabled individual. Some projects built in years past include a laser-pointing device for people who cannot use their hands, a speech aid, a behavior modification device, a hands-free automatic answering and hang-up telephone system, and an infrared beacon to help a blind person move around a room.
Dynamic Modeling and Controller Design for a Piezoelectric Actuation System Used for Machine Tool Control
Authors: Mayhan Paul , Srinivasan K. , Watechagit Sarawoot , Washington G.
Published: December 2021

The dynamic model of a commercially available piezoelectric actuation system intended for use in a machine tool position control system is presented, and its fidelity to observed behavior evaluated. The components of the actuation system are presented and an available nonlinear dynamic model form for piezoelectric actuators, capable of representing actuator hysteresis, used as the basis for the system dynamic model. Parameters in the dynamic model are obtained from manufacturer’s specifications. The resulting actuator model is combined with a nonlinear model of the amplifier, the resulting system model forming the basis of a SIMULINK simulation. System responses based on the simulation are compared with experimentally measured responses. The agreement between simulation and experimental responses is reasonably good at low frequencies, and the model is used for preliminary closed loop position control system evaluations. Specific recommendations for improvement in model accuracy are also made.
Improved Output Active Vibration Control Using Large Aperture Strain Transducers
Authors: Vipperman Jeffrey S.
Published: December 2021

An experimental study is conducted to illustrate the advantages of increasing the aperture size of strain transducers used to perform direct rate feedback (DRFB) control. Twelve individual piezoceramic patches are installed to form a contiguous 3 × 4 array on a simply supported plate structure. The patches are grouped to form four different sized apertures consisting of 1, 4, 8, or 12 individual patches. The open loop results for all four cases show increased coupling into the low frequency modes of the plate as well as more uniform compliance in the frequency response function. As a result, much improved direct rate feedback control performance is achieved.
The Use of Microencapsulated Phase-Change Materials to Enhance the Thermal Performance of Apparel
Authors: Holman Mark E.
Published: December 2021

Recent advancements in the apparel industry have generated increasing interest in phase-change materials (PCMs), due largely to the advantages of microencapsulation. Microencapsulated phase change materials (microPCMs) provide latent heat benefits nearly equal to those of bulk PCMs, yet the PCM remains contained within a shell when melted. As such, microPCMs can be incorporated into a wide variety of products to greatly improve thermal management.

MicroPCMs can be incorporated into both solid and liquid carriers. They can increase the thermal capacitance of solids as much as 10 times, while the effective heat capacities of fluid-based microPCM systems have been shown to increase as much as 40 times (Mulligan et al., 1996).

Extensive microPCM research by Triangle Research and Development Corporation, among others, has ultimately led to the creation of numerous thermally enhanced apparel products. As the capabilities of microPCMs become more widely known, the number and variety of microPCM-based apparel and footwear products continue to grow.
Mechanical Strength Modeling of Particle Strengthened Nickel-Aluminum Alloys Strengthened by Intermetallic γ′ (Ni3Al) Precipitates
Authors: Fragomeni James M.
Published: December 2021

A Nickel-Aluminum alloy strengthened by γ′ (Ni3Al) intermetallic ordered coherent precipitates with a small misfit strain was used a demonstration material to develop a model to predict strengthening behavior during plastic deformation as a consequence of the γ′ particles acting as obstacles to the dislocations and thus impeding their glide motion through the alloy. It was determined that the two most dominate strengthening mechanisms in the Ni-Al system were order hardening when the particles were smaller than the critical looping radius, and Orowan strengthening when the particles were larger than the looping radius. In the overaged condition when the particles are large in size, the dislocations bypass and loop the particles by the Orowan mechanism. In the underaged to peak aged conditions where the particles are usually smaller than the looping radius, the dislocations shear the precipitates during deformation. The total polycrystalline yield strength included contributions from the intrinsic lattice strength, the solid solution strengthening, grain size strengthening, and particle strengthening which included the order hardening and Orowan strengthening contributions. The total mechanical yield strength for a Ni-6.27wt.%A1 alloy was predicted for the peak-aged condition based on the theory for order strengthening and was found to be in good agreement with the experimental peak-strength data for Ni-6.27A1.
Statistics and Quality Management in Manufacturing in a High School Setting
Authors: Dimmer Maureen E. , Pierno Michael C.
Published: December 2021

By incorporating Statistical Process Control (SPC), this high school probability and statistics course provides an answer to the eternal question of students, “How are we ever going to use this?” Students learn the traditional introductory theoretical probability and descriptive statistics and also experience the real-world application, SPC, by doing two manufacturing projects in conjunction with the engineering technology students. The initial project, manufacturing precision 3-D puzzle pieces, offers a straightforward example of the necessity of stringent quality control. Later in the semester, students construct a 50-link chain of identical plastic links, each of which must pass several rigorous quality checks to enable all the pieces to interlock successfully.

The head of the engineering technology department and a mathematics teacher designed the course to better prepare their students for the world of work in the 21st century. Local business people contributed to the design of the course and teach some sessions.
Teaching Mechatronics to the New Generation
Authors: Hayward Gregory P. , Furman Burford J.
Published: December 2021

Students entering undergraduate programs have increasing familiarity with elements of mechatronics such as computer programming skills and familiarity with robotics. A new elective course in mechatronics at San José State University is under development through collaboration of senior mechanical engineering students and faculty to effectively teach mechatronics to the new generation of students. The proposed course is project-based and uses a self-contained microcontroller so that students can work on their project outside of a traditional laboratory space.
Finite Element Analysis of Transient Thermal Problems of Work Rolls in Hot Rolling Process
Authors: Lee James D. , Manzari Majid T. , Shen Yin-Lin , Zeng Wenjun
Published: December 2021

The three-dimensional transient thermal problem of work rolls in the entire hot rolling process has been formulated. It includes the time-varying boundary conditions specified at the roll surface taking the schedule of both rolling and idling cycles into consideration. The corresponding finite element equations are derived and solved by the Runge-Kutta-Verner method. The finite element solutions indicate that the temperature variations in the circumferential direction are overwhelming. Case studies unveil the thermal characteristics of the work rolls in various kinds of mill operations. Numerical results are presented and compared with Guo’s analytical solutions.