bluuebunny/crossref_metadata_2025_split huggingface dataset:
Microfluidics of a Planar Microfabricated Fluid Filter
Authors: Ki Yit-shun Leung , Maillefer Didier , Rey-Mermet Gilles , Monkewitz Peter A. , Renaud Philippe , van Lintel Harald T. G. 
Published: February 2022

Abstract
Design and characterization of a planar microfabricated liquid filter for implantable drug delivery applications is presented. An on-chip liquid filter is required at the inlet of a micromachined membrane pump [1] to ensure trouble-free operation of pump components. The filter, bulk micromachined in silicon, consists of a slightly etched long filtration barrier within a deep wet-etched cavity with asymmetrically offset inlet and exit encapsulated by bonding a pyrex coverslip over the silicon substrate. Minimum filtrate size is thus controlled by the depth h of the barrier etch and can be as slim as 0.1 μm. Flow resistance of the filter is minimized by winding the filtration barrier into a zig-zag. Effects observed during priming of the filters are described here and a model is presented which led to a filter design with vastly improved priming characteristics. The filter fulfills design specifications with respect to proper operation of the micropump, and successfully blocks the transport of 0.48 μm particles as visualized using blue fluorescent microbeads. The gap size achieved in practice was of 0.18 μm for a desired gap size of 0.2 μm. The filter design can also be used as a test structure for the exploration of liquid transport effects in submicron channels. Preliminary results show that in accordance with previous theoretical and experimental work [2,3], there is an increase in apparent viscosity for the flow of aqueous NaCl solutions through submicron-sized gaps.
Pressure Drop Measurements in a Microchannel
Authors: Pfund David , Shekarriz Alireza , Popescu Aristotel , Welty James R. 
Published: February 2022

Abstract
This paper presents the results of experiments performed on single-phase flow in microchannels. Channel depths ranged between 100 and 500 microns, with a W:H ratio greater than 20:1. Water was the primary working fluid in these studies, with the Reynolds numbers (based on the hydraulic diameter of the channel) ranging between 40 and 4000. The experimental setup used allowed measurements of the local pressure drop as well as visualization of the flow patterns within the channel using microscopy. Data presented include friction factors for various channel geometry and surface conditions. We found that the surface roughness tended to increase the laminar friction factor within the channel. Further, for the smoothest channel, as the channel height (or hydraulic diameter) decreased, the laminar friction factor did not depart from the continuum theory predictions. Further, our pressure drop measurements, corroborated with careful flow visualization tests, reveal that the transition Reynolds number is nearly half of what is previously reported for macroscopic channels.
Tribology on the Macro- to Nanoscales of MEMS Materials: A Review
Authors: Bhushan Bharat 
Published: February 2022

Abstract
Silicon-based MEMS devices are made from single-crystal silicon, LPCVD polysilicon films and other ceramic films (Bhushan, 1998). For high temperature applications, SiC films are being developed to replace polysilicon films. Tribology in the MEMS devices requiring relative motion is of importance. Atomic force/friction force microscopy (AFM/FFM) and nanoindentation techniques (Bhushan et al., 1995; Bhushan, 1995, 1998) have been used for tribological studies on micro- to nanoscale on materials of interest. These techniques have been used to study surface roughness, friction, scratching/wear, indentation and boundary lubrication of bulk and treated silicon, polysilicon films and SiC films (Bhushan, 1996a, b; Bhushan et al., 1994, 1997a, b, 1998; Koinkar and Bhushan, 1997; Li and Bhushan, 1998; Sundararajan and Bhushan, 1998; Zhao and Bhushan, 1998). Macroscale friction and wear tests have also been conducted using the ball-on-flat tribometer. (Bhushan and Venkatesan, 1993; Gupta et al., 1993, 1994a, b; Venkatesan and Bhushan, 1993, 1994). Measurements of microscale and macroscale friction forces show that friction values on both scales of all the silicon samples are about the same among different silicon materials and higher than that of SiC. The microscale values are lower than the macroscale values as there is less ploughing contribution in the microscale measurements. Surface roughness has an effect on friction. In microscale and macroscale tests, C+-implanted, oxidized and PECVD oxide-coated single-crystal silicon samples exhibit much larger scratching and wear resistance as compared to untreated samples. Polysilicon films and undoped single-crystal silicon show similar friction and wear characteristics. Doping of polysilicon film does not affect its tribological properties. Microscratching, microwear and nanoindentation, and macroscale friction and wear studies indicate that SiC films are superior when compared to the other materials currently used in MEMS devices. Higher hardness and fracture toughness of the SiC film is believed to be responsible for its superior mechanical integrity and lower friction. Chemically grafted self-assembled monolayers and chemically-bonded liquid lubricants show promising performance for boundary lubrication in MEMS devices.
Cyclic Fatigue Testing of Surface-Micromachined Thermal Actuators
Authors: Conant Robert A. , Muller Richard S. 
Published: February 2022

Abstract
Long-term testing of surface-micromachincd U-shaped thermal actuators has been carried out. Actuators operated at power levels lower than 8 mW (12 μm of displacement) operated satisfactorally for more than 100 million cycles at 660 Hz, with a failure defined as the point at which the displacement decreases by 20%. Plastic deformation had been observed in actuators operated above 8 mW, and the plastic deformation has been shown to be associated with the high temperatures encountered during operation. The failure rate of the actuators is dependent on the total time the actuators are at the elevated temperatures encountered during operation, rather than on the number of actuation cycles. This paper provides a guide for MEMS designers that shows the lifetime of a thermal actuator as a function of its drive power.
Computer-Aided Micro-Mechanism Design
Authors: Sacks Elisha , Allen James 
Published: February 2022

Abstract
This paper describes computer-aided design tools for micro-mechanisms that help designers validate correct function, detect design flaws, and assess the effects of part clearances. The domain characteristics of curved geometry, joint play, and higher pairs render traditional software inappropriate. Our software uses configuration spaces to model the kinematic function of micro-mechanisms. It uses the configuration spaces to perform real-time simulation, to compute functional kinematic tolerances, and to support parametric design. Designers can visualize system function under a range of operating conditions, can find and correct design flaws, and can optimize dynamical function. The software is demonstrated on a surface micromachined counter meshing gear discrimination device developed at Sandia National Laboratory.
Influence of Fabrication and Crystal Orientation on the Strength of Silicon Microridges
Authors: Chen Quanfang , Yao Da-Jeng , Kim Chang-Jin “CJ” , Carman Greg P. 
Published: February 2022

Abstract
The shear strength of microridges fabricated using both anisotropic wet etching (KOH, TMAH and EDP) and dry-etching methods (chlorine RIE) is presented in this paper. Shear strengths obtained using a KOH wet etching is concentration dependent, that is the microridges made with a 45% KOH solution has a strength 65% larger than those by 30% KOH. EDP and TMAH wet etching produce structures whose average strengths are similar to the 30% KOH solution. On the other hand, dry etching chlorine RIE produces structures with strength values 95% higher than the wet etching approaches containing similar crystal orientations. Strength variations are attributed to local stress concentrations. RIE is also used to manufacture structures with different crystal orientations. Test results indicate that microridges with a {110} sidewall has the highest strength because for this case the loading direction (perpendicular to sidewall) has one of the smallest component along the {111} plane (sliding plane of silicon). Microridges made with a sidewall of {100} plane produce the lowest strength value among the three crystal orientations studied.
MHD (Magnetohydrodynamic) Micropump Using Lorentz Force
Authors: Jang Jaesung , Lee Seung S. 
Published: February 2022

Abstract
We present a novel micropump of which pumping mechanism is based upon MHD (Magnetohydrodynamic) principle. The MHD micropump uses Lorentz force as the pumping source. In the micropump, Lorentz force is applied into initially stagnant conducting fluid to drive it in magnetic and electric field to flow in both directions. The performance of the micropump is obtained by measuring the pressure head difference and flow rate as the applied voltage changes from 10 to 60 V DC at 0.19 and 0.44 Tesla. The pressure head difference is 18 mm at 38 mA and the flow rate is 63 μl/min at 1.8 mA when the inside diameter of inlet/outlet tube is 2 mm and the magnetic flux density is 0.44 Tesla.
Flow Past a Micro-Sphere in a Pipe: Effects of Rarefaction
Authors: Liu Hsin-Chih F. , Beskok Ali , Gatsonis Nikolaos , Karniadakis George E. 
Published: February 2022

Abstract
The canonical problem of rarefied gas flow past a sphere in a pipe has been studied in a wide range of Knudsen number (Kn), covering the continuum, slip, and transitional flow regimes. The blockage effects are studied by varying the pipe to sphere diameter ratio H/D, as well as the Knudsen number. The numerical results in the continuum and slip flow regimes are obtained by ΝεκΤαr and μFlow, based on spectral element algorithms for incompressible continuum, and for compressible continuum/slip flows, respectively. The transitional flow regime is investigated by the code F3, based on the direct simulation Monte Carlo (DSMC) method of Bird. Our results show that the drag coefficient CD is inversely proportional to Kn, the Reynolds number Re and H/D. The blockage effects are shown to become negligible for high Knudsen number regime (Kn ≥ 3.5) even for small values of H/D. The sphere in a pipe configuration can be used in designing electro-magnetically driven micro-valve systems.
A Micromechanical Actuator With Capacitive Position Correction for Phase Shifting Diffraction Interferometry
Authors: McConaghy Charles F. , Lee Abraham P. , Sommargren Gary , Phillion Don , Campbell Eugene W. , Trevino Jimmy 
Published: February 2022

Abstract
An electrostatically-actuated micro phase shifter with capacitive position feedback for linearization is presented in this paper. The travel range of the micro phase shifter is 1.2 μm, and a lock-in amplifier capacitive sensing circuit capable of 1.5 nm position accuracy is developed and with a digital signal processor generates a position feedback correction curve to achieve a linearized travel trajectory. The eventual application for this microactuator is to provide linear phase shifting in the phase shifting diffraction interferometer (PSDI) developed at LLNL Which can perform optical metrology down to 2Å accuracy.
First Discrete Time Full-System Inertial Microsensor Performance Simulation Tool
Authors: Pottenger Michael D. , Kaiser William J. 
Published: February 2022

Abstract
We present the first report on a full-system integrated microsensor simulation model, based on discrete-time methods and implemented in SPICE. Included are all electrical and thermomechanical noise sources, proof mass dynamics, differential capacitive transducer bridge, interface circuit, and feedback control. Complete microsensor system performance can be simulated in the time domain, incorporating flicker noise models based on measured data from a commercial CMOS process. Simulation results for two complete inertial sensor system are presented: System I has an open loop resonant frequency of 100Hz, Q factor of 1000, and has a critically damped closed-loop resonance at 1.67kHz; System II is a critically damped open loop sensor with resonance at 1.67kHz. Closed loop operation is demonstrated to improve sensitivity by 106dB at 100Hz.
Automatic Model Order Reduction of a Microdevice Using the Arnoldi Approach
Authors: Wang Frank , White Jacob 
Published: February 2022

Abstract
In this paper we demonstrate that Arnoldi based model-order reduction can be used to generate accurate reduced-order models from linear systems generated by coupled-domain simulation of MEMS devices. In particular, we examine the well-known fixed-fixed beam example and show that when the device is in the linear regime, we can automatically generate a tenth order model that faithfully, reproduces the device characteristics. We also show the limitations of this linearized model approach.
Automatic Model Generation and Analysis for MEMS
Authors: Ljung Per B. , Bächtold Martin 
Published: February 2022

Abstract
Simulating large, realistic MEMS models has previously been prohibitive due to both the extensive user effort required to generate models and the computational cost of such analyses [1]. This work robustly automates efficient and accurate MEMS analysis by eliminating substantially all user interaction required to generate accurate 3D simulations of devices described by photolithographic masks. This automatic procedure allows large, realistic MEMS devices to be accurately simulated in less than one hour on personal computers.
Utilizing Existing TCAD Simulation Tools to Create Solid Models for the Simulation Based Design of MEMS Devices
Authors: Wilson Nathan M. , Dutton Robert W. , Pinsky Peter M. 
Published: February 2022

Abstract
This paper gives an overview of MEMS simulation and the computational requirements in the field from the prospective of creating realistic geometry based on process simulation. We motivate the needs for such geometry, and discuss in detail one approach to create pseudo 3-D geometry from 2-D process simulation. Three different methods to perform booleans critical to the pseudo-3D technique are discussed in detail.
Optimized Compliance With Supplemental Indication Requirements: Leveraging Non-Intrusive Techniques, Preexisting Line-Ups and Programs to Meet 10CFR50.55a(b)(3)(xi)
Authors: Arnold Eli , Cruz Domingo 
Published: February 2022

Abstract
To ensure safe operation of the United States’ nuclear power plants, the Nuclear Regulatory Commission enacted 10CFR50.55a(b)(3)(xi) requiring the verification of valves’ capability to control plant process conditions. Palo Verde Generating Station implemented the requirement with a focus on crediting existing operational and testing activities, iterating to optimize implementation. The station credits valve diagnostics, operational activities, and component testing programs wherever possible. Where testing and operations are insufficient to meet the requirement, phased-array ultrasonic equipment is used to verify stem-disc connection integrity. Palo Verde is fully compliant with the requirements of 10CFR50.55a(b)(3)(xi). This suggests compliance at other pressurized water reactors can be achieved primarily by documenting existing plant activities with minimal new testing activities required.
NRC Inspection Manual Inspection Procedure 71111 Attachment 21N.02: Design-Basis Capability of Power-Operated Valves Under 10 CFR 50.55a Requirements Inspection Implementation Update and Lessons Learned
Authors: Bollock Douglas 
Published: February 2022

Abstract
On July 26, 2019, the NRC issued Inspection Procedure 71111, Attachment 21N.02 (IP 71111.21N.02), “Design-Basis Capability of Power-Operated Valves Under 10 CFR 50.55a Requirements.” The objective of this inspection procedure is to assess the reliability, functional capability, and design basis of risk-important power-operated valves (POVs) as required by Section 55a, “Codes and Standards,” in Part 50, “Domestic Licensing of Production and Utilization Facilities,” of Title 10, “Energy,” in the Code of Federal Regulations (10 CFR 50.55a). The NRC staff has implemented this inspection procedure at operating nuclear power plants in the United States (U.S.) since January 2020 and has gained lessons learned through implementation of and feedback from the inspections. The staff has held a public meeting with nuclear power plant licensees to discuss the lessons learned from the inspection activities in December 2020. This paper describes the status of the ongoing NRC staff activities for POV inspections at operating U.S. nuclear power plants and the lessons learned through implementation of the inspections.
Secondary cratering on Earth: The Wyoming impact crater field
Authors: Kenkmann Thomas , Müller Louis , Fraser Allan , Cook Doug , Sundell Kent , Rae Auriol S.P. 
Published: February 2022

Abstract
A large number of small impact structures have been discovered in Wyoming, USA, and we raise the question of how this accumulation occurred. We document 31 crater structures of 10–70 m diameter with corresponding shock features but missing meteorite relics. All craters occur along the outcrops of the uppermost Permo-Pennsylvanian Casper Sandstone Formation and are ~280 m.y. old. Their spatial arrangement shows clusters and ray-like alignments. Several craters have elliptical crater morphologies that allow the reconstruction of impact trajectories. The radial arrangement of the trajectories indicates that the craters are secondary craters formed by ejecta from a primary crater whose likely position and size are reconstructed. Modeling ballistic trajectories and secondary crater formation indicates that impacts occurred at around 700–1000 m/s and caused small shock volumes with respect to crater volumes. This is the first field of secondary craters found on Earth, and we disentangle its formation conditions.
Reassessment of ocean paleotemperatures during the Late Ordovician
Authors: Barney Bryce B. , Grossman Ethan L. 
Published: February 2022

Abstract
The Late Ordovician is a paradox, with a greenhouse climate shifting to an icehouse climate during a time of presumably high CO2 levels. We used clumped isotope (Δ47) microanalysis of fossil brachiopod shells to determine paleotemperatures of North America (Cincinnati Arch) during the Katian (453–443 Ma). Microanalyses of fossil brachiopods yielded a right-skewed distribution of clumped isotope temperatures [T(Δ47)] ranging from 25 °C to 55 °C with a mode of 32 °C and a mean of 36 °C. To test the impact of Δ47 reordering (reequilibration of 13C-18O bonding) at burial temperatures on T(Δ47), we applied a Monte Carlo simulation to a Δ47 reordering model based on the burial history. Because the reordering simulation indicated partial reordering, we used the simulation results to back-calculate T(Δ47) and correct the reordering effect. Correcting for reordering decreased the mean T(Δ47) by only ~1 °C, to 35 °C, and did not change the mode (32 °C). These temperatures are lower than those of previous studies, but still suggest that the Late Ordovician climate of the Cincinnati Arch was warmer than the modern subtropical seas. However, carbonate facies in these strata argue for upwelling of cool water; thus, typical subtropical surface waters may have been as warm as 35 °C approaching the Hirnantian glaciation. Seawater δ18O values derived from back-calculated T(Δ47) and brachiopod δ18O values average −0.3‰ ± 0.6‰ relative to Vienna standard mean ocean water (VSMOW), consistent with the value expected for subtropical surface waters in a greenhouse Earth, assuming a constant seawater-δ18O model.
Implications for Ediacaran biological evolution from the ca. 602 Ma Lantian biota in China
Authors: Yang Chuan , Li Yang , Selby David , Wan Bin , Guan Chengguo , Zhou Chuanming , Li Xian-Hua 
Published: February 2022

Abstract
The morphologically differentiated benthic macrofossils of algae and putative animal affinities of the Lantian biota in China represents the oldest known Ediacaran macroscopic eukaryotic assemblage. Although the biota provides remarkable insights into the early evolution of complex macroeukaryotes in the Ediacaran, the uncertainty in its age has hampered any robust biological evaluation. We resolve this issue by applying a petrographic-guided rhenium-osmium (Re-Os) organic-bearing sedimentary unit study on the Lantian biota. This work confines a minimum age for the first appearance of the Lantian biota to 602 ± 7 Ma (2σ, including decay constant uncertainty). This new Re-Os date confirms that the Lantian biota is of early–mid Ediacaran age and temporally distinct from the typical Ediacaran macrobiotas. Our results indicate that the differentiation and radiation of macroscopic eukaryotes, and the evolution of the primitive, erect epibenthic ecosystem, occurred in the early–mid Ediacaran and were associated with highly fluctuating oceanic redox conditions. The radiogenic initial 187Os/188Os ratios derived from the Lantian (1.14 ± 0.02) and other Ediacaran shales invoke oxidative weathering of upper continental crust in the early–middle Ediacaran, which may have stimulated the evolution of life and oceanic-atmospheric oxygenation. Integrated with published Ediacaran chronological and geochemical data, our new Re-Os geochemical study of the Lantian black shale provides a refined, time-calibrated record of environment and eukaryote evolution during the Ediacaran.
Multicentre point-prevalence survey of antibiotic use and healthcare-associated infections in Ethiopian hospitals
Authors: Fentie Atalay Mulu , Degefaw Yidnekachew , Asfaw Getachew , Shewarega Wendosen , Woldearegay Mengistab , Abebe Ephrem , Gebretekle Gebremedhin Beedemariam 
Published: February 2022

ObjectiveEffective antimicrobial containment strategies such as Antimicrobial Stewardship Programs (ASPs) require comprehensive data on antibiotics use which are scarce in Ethiopia. This study sought to assess antibiotics use and healthcare-associated infections (HCAIs) in Ethiopian public hospitals.DesignWe conducted a cross-sectional study using the WHO point-prevalence survey protocol for systemic antibiotics use and HCAIs for low/middle-income countries.SettingThe study was conducted among 10 public hospitals in 2021.ParticipantsAll patients admitted to adult and paediatric inpatient and emergency wards before or at 08:00 on the survey date were enrolled.Outcome measureThe primary outcome measures were the prevalence of antibiotic use, HCAIs and the hospitals’ readiness to implement ASP.ResultsData were collected from 1820 patient records. None of the surveyed hospitals had functional ASP. The common indication for antibiotics was for HCAIs (40.3%). Pneumonia was the most common bacterial infection (28.6%) followed by clinical sepsis (17.8%). Most treatments were empiric (96.7%) and the overall prevalence of antibiotic use was 63.8% with antibiotics prescription per patient ratio of 1.77. Ceftriaxone was the most commonly prescribed antibiotic (30.4%) followed by metronidazole (15.4%). Age, having HIV infection, ward type, type of hospital, catheterisation and intubation history had significant association with antibiotic use. Patients who were treated in paediatric surgical wards were about four times more likely to be on antibiotics compared with patients treated at an adult emergency ward. Patients on urinary catheter (adjusted OR (AOR)=2.74, 95% CI: 2.04 to 3.68) and intubation device (AOR=2.62, 95% CI: 1.02 to 6.76) were more likely to be on antibiotics than their non-intubated/non-catheterised counterparts. Patients treated at secondary-level hospitals had 0.34 times lower odds of being on antibiotics compared with those in tertiary hospitals.ConclusionsAntibiotic use across the surveyed hospitals was common and most were empiric which has both practical and policy implications for strengthening ASP and promoting rational antibiotics use.