bluuebunny/crossref_metadata_2025_split huggingface dataset:
Design, Analysis, Fabrication, and Testing of a MEMS Contact/Bending Sensor With Improved Dynamic Range
Authors: Truong Thieu Q. , Barnes Terrence G. , Lu Xiaoqing , Adams George G. , McGruer Nicol E. 
Published: December 2021

Abstract
Contact/bending sensors have been designed, analyzed, fabricated, and tested. These sensors are to be mounted on flexible antennae in order to provide a sense of touch for ambulatory underwater robotic lobsters. These biomimetic vehicles are designed to mimic some of the behavior patterns of real lobsters and are being built in order to search for and destroy mines in the littoral zone [1].
Two contact/bending sensors have been developed — a “standard” sensor and a “stopper” sensor. The standard sensor and stopper sensor are cantilever beam type microswitches fabricated on a thin flexible substrate. These sensors were fabricated using the Northeastern University Metal Micromachining (NUMEM) process [2]. The purpose of the stopper sensor design is to increase the dynamic range and alleviate the sensitivity limitations that are inherent in the standard sensor design.
Tests have shown the standard sensors close at a substrate radius of curvature that is 25% greater than the design values. Tests and SEM micrographs of the stopper sensors have shown that there are some processing issues which need to be addressed.
Measurement of Shear Stress and Temperature Using MEMS Fabricated Sensors
Authors: Breuer Kenneth S. , Bayt Robert L. , Nayaar Anju 
Published: December 2021

Abstract
The design, fabrication and testing of microfabricated thermal shear stress and temperature sensors are sensors is discussed. The devices are fabricated on a silicon substrate with a platinum sensor element 5 microns wide, 1000-Å thick and of varying length. The electrical leads are comprised of 5000-Å of gold deposited above the platinum sensor metal. The sensing area is isolated from the substrate by a thin membrane of silicon nitride covering a vacuum cavity. Test results are presented confirming the good thermal isolation of the sensor element from the substrate as well as the successful operation of the device.
Infrared Vision Using an Uncooled Thermo-Opto-Mechanical Camera: Design, Microfabrication, and Performance
Authors: Mao M. , Perazzo T. , Kwon O. , Zhao Y. , Majumdar A. , Varesi J. , Norton P. 
Published: December 2021

Abstract
An uncooled infrared (IR) camera that is based on thermomechanical sensing and visible optical readout has been developed. The system contains a focal plane array (FPA) consisting of bimaterial cantilever beams made of silicon nitride (SiNx) and gold (Au) in each pixel. Absorption of incident IR radiation in the 8–14 μm wavelength range by SiNx in each cantilever beam raises its temperature, resulting in proportional deflection due to mismatch in thermal expansion of the two cantilever materials. To maximize the thermal performance, the conductance of each pixel was reduced to about five times of the radiation conductance. Based on thermomechanical analysis, the geometrical shape of the pixels were designed to maximize the cantilever sensitivity within the constraints of the pixel size and layout. Microfabrication of stress-balanced bimaterial cantilevers was achieved by varying the silicon concentration along the thickness of the SiNx films in order to balance the residual tensile stress in the Au film and the Cr adhesion layer between Au and SiNx. The optical design of each pixel was based on IR properties of the cantilever materials, IR absorption enhancement due to resonance cavity formation, as well as visible optics of deformable diffraction gratings. The latter formed the foundation for two different optical readout techniques that were both used for IR imaging. The results suggest that objects at temperatures as low as 30 °C can be imaged with the best noise-equivalent temperature difference (NETD) in the range of 2–5 K. It is estimated that further improvements that are currently being pursued can improve NETD to about 10 mK.
A New Driving Principle for Micromechanical Torsional Actuators
Authors: Schenk Harald , Dürr Peter , Kunze Detlef , Kück Heinz 
Published: December 2021

Abstract
An electrostatic driving principle for micromechanical torsional actuators is presented which allows to excite mechanical oscillations with large deflection angles at low driving voltages. This is achieved by a special electrode configuration which enables the usage of small electrode gaps. The functionality is demonstrated by various 1D-scanner chips which are fabricated in a CMOS-compatible process. When the excitation is synchronized with the oscillation a maximum deflection angle is obtained. For this case a theoretical description of the characteristic curve is given and compared to experimental results. Furthermore, FEM calculations on the deflection dependence of the capacitance are presented.
Simulation of Microfluidic Systems: A New Approach Considering Capillarity
Authors: Mellmann Jörg , Sesterhenn Michael , Löhr Markus , Stierle Bernhard , Strobelt Tilo , Zengerle Roland , Sandmaier Hermann 
Published: December 2021

Abstract
In this paper, a toolbox of lumped models for simulating (self-)priming and emptying of complex capillary networks is presented. Each model is a kind of an all-in-one-model, that considers inertia, friction, gravitation and capillarity and has been implemented on a conventional, commercially available, mixed-signal system-level simulator.
The toolbox contains fundamental microfluidic components which are lines with micromachined geometries, fittings, tees, dispensers and media transition elements.
With these all-in-one-models it is now possible for the first time to layout complex capillary networks by simulating not only the dynamic behavior of filled systems but even the priming and emptying.
Topspot: A New Method for the Fabrication of Biochips
Authors: Gruhler Holger , Hey Nicolaus , Müller Martin , Békési Stefan , Freygang Michael , Sandmaier Hermann , Zengerle Roland 
Published: December 2021

Abstract
We present a new method for generating microarrays of liquid droplets. This is of basic importance for the fabrication of so called biochips. To generate a microarray we use a print-module containing 24 nozzles. Each nozzle is connected to one of 24 different reservoirs on the same print-module. By applying a high acceleration to the print-module it can be achieved that all of the 24 nozzles eject a small droplet at the same time. This effect is due to the inertia of the liquid inside the print-module. This new method makes the production of low and medium density biochips much faster and significantly cheaper.
Numerical Modeling of Electroosmotically Driven Micro Flows
Authors: Dutta Prashanta , Beskok Ali , Warburton Timothy C. 
Published: December 2021

Abstract
Electroosmotically driven flows in micro-channels are analyzed analytically and numerically. Semi-analytical relations for the velocity and pressure distributions in micro channels are obtained for electric double layers that are much smaller than the channel height, by using the Helmholtz Smoluchowski velocity. Analytical relations for wall shear stress and pressure distribution are obtained. Amplification of the normal and shear stresses on the walls are observed and documented. A high-order (h/p type) spectral element method is developed, and verified for numerical simulation of electroosmotic micro fluidic flows. Finally, flow through a step channel geometry is analyzed to document the interaction of the electroosmotic forces with adverse pressure gradients. Significant changes within the separation patterns are observed.
Factors Influencing the Maintenance of Speed: A Driver Model Analysis
Authors: Thakur Kailash Prasad 
Published: December 2021

Abstract
This paper presents a driver model analysis of the maintenance of speed on highways by drivers of various capabilities. The results indicate that for an expert driver the speed is highly correlated with the free distance in front of the vehicle (or gap with the lead vehicle). Whereas, for a novice driver the speed is very poorly correlated with the gap. This correlation is always positive and varies between 0.05 for novice driver and 0.85 for expert driver. The correlation of speed with the risk-time (time to impact) showed a different trend. This correlation is negative and varies between 0.5 for an expert driver to 0.8 for novice ones. The results compare fairly well with the laboratory-based driver simulation studies carried out by Charlton. The effect of road roughness upon the maintenance of speed, gap and risk-time is also investigated.
Polyethylene Wear Characteristics in Retrieved Total Knee Replacements
Authors: Hall Emily A. , Bland Tracie M. , Lemons Jack E. , Cuckler John M. , Eberhardt Alan W. 
Published: December 2021

Abstract
Since the first observed failures of polyethylene in total knee replacements, researchers have documented wear patterns in an effort to understand the failure mechanisms associated with total knee replacements (TKR). This study documents five types of wear observed in polyethylene components from retrieved TKR, as well as gross deformation characteristics. Pertinent patient data and the type of polyethylene are also noted. Results show significant occurrence of pitting, delamination and abrasion in the majority of the components studied, consistent with previous reports.
Casing Design for an Oxygen Concentrator
Authors: Swindle Stephanie H. , Todd Beth A. , Cuttino James F. 
Published: December 2021

Abstract
Human bodies depend on a steady flow of oxygen for the heart and lungs. When a person has Chronic Obstructive Pulmonary Disorder (COPD), a device called an oxygen concentrator can be used to improve quality of life. An oxygen concentrator is an electrically powered device that takes in room air and converts it to an oxygen rich gas mixture suitable for breathing.
Although a few models are battery powered, oxygen concentrators are not easily portable because they are bulky and weigh between 25–50 lbs. In this study, components were identified for re design to reduce the overall weight of the device. For instance, the concentrator casing was identified as its heaviest component. Using finite element analysis, changes in wall thickness and dimensions can be investigated to reduce weight while maintaining structural integrity. By reducing the weight of the casing, the oxygen concentrator will be easier to transport.
Biomechanical Aspects of Odontoid Fracture Etiology: A Finite Element Investigation
Authors: Puttlitz Christian M. , Goel Vijay K. , Clark Charles R. 
Published: December 2021

Abstract
Fractures of the odontoid process of the second cervical vertebra comprise 7–13% of all cervical spine fractures. Anderson and D’Alzono [1974] have classified these fractures into three categories: Type I, Type II, and Type III. Type I fractures are oblique, usually avulsion, fractures of the superior-most aspect of the odontoid. Type II fractures, the most commonly-occurring, are produced at the juxtaposition of the process and the C2 body. Type III fractures involve propagation of the fracture through the C2 body.
Unsteady Flows Within a 2D Model of Multiple Lung Bifurcations
Authors: Ramuzat A. , Richard H. , Riethmuller M. L. 
Published: December 2021

Abstract
In our environment, chronic pulmonary illness due to pollution effects or asthmatic problems are increasing. To identify the contribution of pollution effect on the alterations in breath patterns, a better understanding of the human pulmonary system is needed. As a result, fields to be investigated are mostly flows in the lungs at high breathing frequency and aerosol deposition in lung bifurcations under unsteady conditions. The respiration pattern has to be better understood and investigated, to have the possibility to get the most appropriate palliative treatment. Most of the medical treatments are based on aerosol deposition in the bronchial tree.
The lung is a complex network of 23 successive generations of bifurcation (Weibel, 1963). The airways, from the trachea to the alveolar zone, divide by dichotomy and become shorter and narrower as they penetrate deeper into the lung. As a result, in vivo investigations of pulmonary flows are not possible, and in vitro experiments in models have to be performed.
Flows in the bifurcating airways of the lung are modeled to determine velocities and pressure fields. A complete description of steady flow in a single 3D bifurcation has been previously performed by experimental and numerical modeling. As a result of this study, it has been shown that the first bifurcation influences the flow in the second and in the third bifurcation when the length of the second bifurcation is not sufficiently long. To extend the investigations to a system of three generations, an experimental study of steady and unsteady flows has been carried out on a 2D multiple bifurcations model.
Application of a Robotic/UFS Testing System to the Measurement of Lumbar Spine Structural Properties
Authors: Doehring Todd C. , Gilbertson Lars G. , Moon Seong-Hwan , Kang James D. , Woo Savio L.-Y. 
Published: December 2021

Abstract
This study focuses on the application of new experimental techniques (robotic/UFS testing system), analytical tools (FEA), and physical models to the investigation of lumbar functional spinal unit structural properties.
Wall Shear Stress Distribution on the Surface of Realistic Endothelial Cell Model
Authors: Fukushima Shuichiro , Nagatsu Ai , Kaibara Makoto , Oka Kotaro , Tanishita Kazuo 
Published: December 2021

Abstract
Wall shear stress induced by blood flow affects morphology and physiology of endothelial cells. The specific mechanisms of mechano-biological interactions alternating shapes and functions have not been identified in the cells, because of the lack of a detailed description of microscopic flow near the cell surface. We therefore developed velocimetry using expanded cell model and demonstrated that the microscopic flow depended on three-dimensional cell shape (Fukushima et al., 1997, 1998). Furthermore, we determined wall shear stress distribution on cultured endothelial cells experimentally.
Evolutionary Biology of Airway Clearance
Authors: Krumpe Peter E. 
Published: December 2021

Abstract
The survival of air breathers depends upon maintaining clear airways. The primary defense of the airways under normal conditions is the mucociliary escalator. Only under conditions of airway inflammation does cough clearance mechanisms become predominant. In order to facilitate the expectoration of mucous and retained particulates, cells, and debris, coupling between the air stream and the mucous layer must occur. High linear velocity of the airstream and unstable flow regimes (vortices, eddies) facilitates development of waves in the mucous layer. Expectoration requires a catastrophic separation of mucous from underlying airway structures. The response of airways is initially to secrete a deeper mucous layer, and to remodel airway glands to produce a mucous blend having a higher elastic modulus. Mucous rheologic properties seem to be tailored by the presence of inflammation to become more easily cleared, even at lower air flow rates which are characteristic of lung disease. Airway oscillations (wheezes and rhonchi) which are physical findings associated with airway inflammation may further enhance mucous clearance by adding additional energy to the mucous layer, aiding catastrophic separation. Thus airway clearance is a highly evolved and coordinated example of evolutionary biology.
Impact of Washout Blades in a Multiple Disk Centrifugal Blood Pump
Authors: Holmes Michelle J. , Miller Gerald E. 
Published: December 2021

Abstract
A multiple disk, centrifugal blood pump (MDCP) for use as a ventricular assist device or as a bridge to transplant device has previously been designed and its output characteristics have been analyzed (Miller et al. 1990, 1993). The propelling mechanism of this device consists of six multiple disks assembled in a parallel configuration. Upon rotation these disks create centrifugal and shearing forces, which work to propel the fluid. This pump operates at lower rotation rates than other rotary blood pumps. The lower rotation rates reduce the chance for hemolysis, but may promote thrombosis formation due to stagnant blood flow. Previous flow visualization studies conducted by Miller et al. (1995) analyzed the blood flow patterns within the device. Results of this study indicated a region of flow stagnation between the last solid disk and the housing. In this investigation, further studies were performed that verified this recirculation. To provide washout of this region, eight, small Lexan blades were attached to the back of the last disk. Reevaluation of the flow patterns, following the blade attachment, revealed that the addition of the blades was successful in producing washout, thus reducing the possibility of thrombosis formation.
Elevated Mean Translesional Pressure Gradients and Flow Limitation in Significant Human Coronary Stenoses Before Angioplasty
Authors: Banerjee Rupak K. , Back Lloyd H. , Back Martin R. , Cho Young I. 
Published: December 2021

Abstract
Blood flow was simulated in patients (Wilson et al. 1988) with physiologically significant coronary lesions (minimal lesion size dm = 0.95 mm; 68% mean diameter stenosis; measured coronary flow reserve (CFR) of 2.3) by using computational hemodynamics. Computed mean pressure gradients Δp˜ were about 9 mm Hg for basal flow, and flow limiting values about ∼ 35 mm Hg. Mean hyperemic flow rates were about 115 ml/min, and distal mean coronary pressures ∼ 55 mm Hg, a level known to cause ischemia in the subendocardium (Brown et al. 1984), and consistent with the occurrence of angina in the patients.
Development of Thin Metal Film Deposition Process for the Intravascular Catheter
Authors: Chung Seok , Chang Jun Keun , Han Dong Chul 
Published: December 2021

Abstract
To make some MF.MS devices such as sensors and actuators be useful in the medical application, it is required to integrate this devices with power or sensor lines and to keep the hole devices biocompatible. Integrating micro machined sensors and actuators with conventional copper lines is incompatible because the thin copper lines are not easy to handle in the mass production. To achieve the compatibility of wiring method between MEMS devices, we developed the thin metal film deposition process that coats micropattered thin copper films on the non silicon-wafer substrate. The process was developed with the custom-made three-dimensional thin film sputter/evaporation system. The system consists of process chamber, two branch chambers, substrate holder unit and linear/rotary motion feedthrough. Thin metal film was deposited on the biocompatible polymer, polyurethane (PellethaneR) and silicone, catheter that is 2 mm in diameter and 1,000 mm in length. We deposited Cr/Cu and Ti/Cu layer and made a comparative study of the deposition processes, sputtering and evaporation. The temperature of both the processes were maintained below 100°C, for the catheter not melting during the processes. To use the films as signal lines connect the signal source to the actuator on the catheter tip, we machined the films into desired patterns with the eximer laser. In this paper, we developed the thin metal film deposition system and processes for the biopolymeric substrate used in the medical MEMS devices.
Direct Flow Analysis on a Reconstructed 3D Image of a Physiologic Porcine Aortic Trifurcation
Authors: Banerjee Rupak K. , Huddleston Matthew , Sohan Shailendra Singh , Friedman Morton H. 
Published: December 2021

Abstract
The present study describes a detailed methodology, from 3D image reconstruction to flow analysis, for simulating the flow field in real arterial geometries. The procedure takes advantage of the latest state of the art technology in solid modeling, and is illustrated by application to a porcine aortic trifurcation. A Stereolithography (STL) format representation of the physical geometry is used in the Gambit™ (1998) preprocessor to create an identical, “virtual” geometry, which is subsequently meshed for flow analysis. With this simplified procedure, it is possible to take MRI or CAT scan images and perform computational flow analysis within physiologic-passageways, using commercially available solvers.
The Effects of Osmotic Pressure on the Viscoelastic and Physical Properties of Articular Chondrocytes
Authors: Guilak Farshid , Ting-Beall H. Ping 
Published: December 2021

Abstract
Mechanical stress is an important factor in the regulation of chondrocyte metabolism and the maintenance of the cartilage extracellular matrix. Previous studies have shown that compression of cartilage explants alters cellular metabolism in a time- and spatially-varying manner which is correlated with the mechanical environment within the extracellular matrix [1]. Furthermore, cellular response has been shown to be influenced by mechanical, electrical, and physicochemical events which are coupled to deformation of the cells and the extracellular matrix. Therefore, detailed information on the stress-strain and physicochemical environments of individual cells in response to mechanical and osmotic stresses would improve our understanding of the sequence of events involved in mechanical signal transduction [2–4]. The goal of this study was to quantify the osmotic and viscoelastic properties of isolated chondrocytes and to test the hypothesis that the mechanical properties of the chondrocyte are influenced by their physicochemical (osmotic) environment.
Real-Time Observations of the Behavior of Cells Under Controlled Pressure and Shear Loads
Authors: Tsourkas Andrew , Bao Gang 
Published: December 2021

Abstract
The effect of mechanical loading on cells has aroused a great deal of interest in recent years. It is now widely accepted that mechanical loading is critical for both cell form and function. Although shearing of cells through fluid flow and tensile testing of cells have been widely practiced, there is still a lack of experiments focusing on the effects of controlled pressure and shear loads on cell behavior. The presence of compressive and shear deformations can be seen in a variety of cells ranging from chrondocytes during walking to cardiac myocytes during the cardiac cycle. The aim of our research is to relate the rate and magnitude of shear deformation in addition to applied pressure to issues such as restructuring of the cytoskeleton (i.e. microtubules), alterations in ion release and influx, and changes in cell function. The effects of changing the extra-cellular matrix (ECM) on the cellular response under pressure and shearing are also studied. By observing the effects of combined compression and shear on cells such as chondrocytes and cardiac myocytes, we hope to better understand the causes of diseases like osteoarthritis and congestive heart failure in connection to mechanical loads.