bluuebunny/crossref_metadata_2025_split huggingface dataset:
Postoperation Dose Rate Estimates for the Very-Small, Long-Life, Modular Reactor
Authors: Palomino Luis M. , El-Genk Mohamed S. , Schriener Timothy M. 
Published: October 2019

Abstract
The very-small, long-life, modular (VSLLIM) nuclear reactor generates 1.0–10 MWth, for ∼92 and 5.8 full power years (FPY), respectively, without refueling. This factory fabricated, assembled, and sealed reactor is cooled by natural circulation of in-vessel liquid sodium (Na). It offers redundant control and passive operation and decay heat removal features. The VSLLIM reactor, together with other plant components for generating electricity using open Brayton cycle, is deployable on a portable platform. Alternatively, multiple units could be installed at a site and use high thermal efficiency Rankine or supercritical CO2 cycles for electricity generation. Extensive analyses are performed to estimate postoperation external biological dose rate and the storage time required on-site for this dose rate to decrease to or below the U.S. federal transportation limit (0.2 rem/h or 2 mSv/h) for safe handling, removal, and replacement with a new unit loaded with fresh fuel. Results show that gamma photons emission from the uranium nitride (UN) fuel and the activated HT-9 steel cladding for the UN fuel rods, the core structure, and the reactor primary vessel, is a major contributor to the radiological source term, and the external biological dose rate estimates. After operating at 10 MWth for 5.8 FPY, using 6 cm thick lead shielding of the reactor guard vessel, decreases the postoperation external biological dose rate to be in compliance with the federal limit, only after∼ 103 days of postoperation on-site storage.
Proof of Concept of a Surrogate High-Adhesion Medical Tape Using Photo-Thermal Release for Rapid and Less Painful Removal
Authors: Lim Saniel D. , Svanevik Carl C. , Fauver Mark E. , Nelson Leonard Y. , Taroc Ann-Marie , Emery Ashley F. , Seibel Eric J. 
Published: October 2019

AbstractMedical tapes often hold critical devices to the skin so having high adhesion for the lifespan of this product is of great importance. However, the removal process is challenging for caregivers and patients alike, often a painful process that can cause medical adhesive-related skin injury (MARSI). By using an industrial thermally sensitive tape, a surrogate photosensitive tape was developed that switched from the equivalent of high-adhesion medical tape to low-adhesion medical tape. This resulted in an 86% reduction in the average peel strength when heated from 45 to 55 °C using a custom test apparatus. To photo-release the prototype tape (PT), a near-infrared (NIR) absorbing layer was painted on the visibly clear thermal-sensitive tape and an NIR optical wand using 15-LEDs (940 nm) with thermal feedback control was designed and tested. Preliminary performance of photo-to-thermal conversion was numerically modeled with transient results matching experimental measurements with 96.8% correspondence. Using the verified energy conversion model of the surrogate photosensitive tape, a new NIR optical wand was designed for rapid and noncontact release of a future medical tape at 10 deg lower than the release temperature (RTemp) of the custom adhesive, called UnTape. Numerical simulations compared to the thermal skin pain threshold of 45 °C predicts photo-release within 1.1 s of NIR exposure (85.5% absorption in PT at &lt; 1.3 W/cm2). The unique properties of the multifunctional UnTape system (tape and portable NIR wand) may allow even stronger skin adhesion for critical medical devices while concurrently reducing the risk of MARSI upon photo release and easy removal.
Analysis of the Evolution of the Structure of a Surface With Pyramidal Asperities in Contact With a Hard and Smooth Plane
Authors: Bourassia Bensaad , Brahim Bourouga 
Published: October 2019

Abstract
This research deals with the evolution of the structure of the sapphire–brass interface due to the variation of contact pressure. This evolution primarily affects the essential parameters that govern the thermal contact resistance (TCR), namely, the contact point density N, the ratio of real area of contact S*, and the distance d separating the median contact planes. The combination of three measurement techniques, namely, profilometry, imaging, and mechanical characterization, was used for the purpose of investigating the structural variation of the interface. Alternatively, the TCR, which prevails at the interface, was estimated. Thus, the object of our study is to propose an original and new experimental approach allowing at the same time the precise measurement of the TCR and the estimate of the contact parameters of the interface studied constituting input data to the theoretical models of TCR. The estimated values given by these last are then compared with those measured. Through this approach, we try to open new ways of experimentation that would tend to reinforce the effort of TCR modeling. The results obtained showed that the roughness parameters Ra and Rq are independent of loading. The roughness Rp, which is considered equal to d, is sensitive to loading and has the same decreasing behavior under the effect of loading. The determination of S*, using the hardness testing, is even more relevant when the effective hardness Hc is considered. Analysis of data for the estimation of the TCR shows that the comparisons with the reference model (Bardon) attest to the relevance of our approach.
Multifidelity Analysis of Acoustic Streaming in Forced Convection Heat Transfer
Authors: Agarwal Tapish , Rahbari Iman , Saavedra Jorge , Paniagua Guillermo , Cukurel Beni 
Published: October 2019

Abstract
This research effort is related to the detailed analysis of the temporal evolution of thermal boundary layer(s) under periodic excitations. In the presence of oscillations, the nonlinear interaction leads to the formation of secondary flows, commonly known as acoustic streaming. However, the small spatial scales and the inherent unsteady nature of streaming have presented challenges for prior numerical investigations. In order to address this void in numerical framework, the development of a three-tier numerical approach is presented. As a first layer of fidelity, a laminar model is developed for fluctuations and streaming flow calculations in laminar flows subjected to traveling wave disturbances. At the next level of fidelity, two-dimensional (2D) U-RANS simulations are conducted across both laminar and turbulent flow regimes. This is geared toward extending the parameter space obtained from laminar model to turbulent flow conditions. As the third level of fidelity, temporally and spatially resolved direct numerical simulation (DNS) simulations are conducted to simulate the application relevant compressible flow environment. The exemplary findings indicate that in certain parameter space, both enhancement and reduction in heat transfer can be obtained through acoustic streaming. Moreover, the extent of heat transfer modulations is greater than alterations in wall shear, thereby surpassing Reynolds analogy.
Analytic Modeling of Heat Transfer to Vertical Dense Granular Flows
Authors: Watkins Megan F. , Chilamkurti Yesaswi N. , Gould Richard D. 
Published: October 2019

Abstract
The high packing fractions of dense granular flows make them an attractive option as a heat transfer fluid or thermal energy storage medium for high temperature applications. Previous works studying the heat transfer to dense flows have identified an increased thermal resistance adjacent to the heated surface as a limiting factor in the heat transfer to a discrete particle flow. While models exist to estimate the heat transfer to dense flows, no physics-based model describing the heat transfer in the near-wall layer is found; this is the focus of the present study. Discrete element method (DEM) simulations were used to examine the near-wall flow characteristics, identifying how parameters such as the near-wall packing fraction and number of particle-wall contacts may affect the heat transfer from the wall. A correlation to describe the effective thermal conductivity (ETC) of the wall-adjacent layer (with thickness of a particle radius) was derived based on parallel thermal resistances representing the heat transfer to particles in contact with the wall, particles not in contact with the wall, and void spaces. Empirical correlations based on DEM results were developed to estimate the near-wall packing fraction and number of particle-wall contacts. The contribution from radiation was also incorporated using a simple enclosure analysis. The ETC correlation was validated by incorporating it into dense flow models for chute flows and cylindrical flows and comparing with the experimental data for each.
A Mathematical Analysis of Directional Solidification of Aqueous Solutions
Authors: Ukpai Gideon , Rubinsky Boris 
Published: October 2019

Abstract
Horizontal directional solidification techniques have been broadly utilized for the freezing of biological matter under conditions in which the freezing rate during solidification must be controlled and known. Directional solidification is used for diverse applications such as fundamental research on freezing of biological materials, cryopreservation of biological matter, and tissue engineering. This study is motivated by our intent to use directional solidification as a simplified model for the study of three-dimensional (3D) cryoprinting. In evaluating directional solidification in the context of 3D cryoprinting, we realized that current mathematical models of directional solidification are not adequately representative for this purpose, because they are simplified and one-dimensional (1D). Here, we introduce an experimentally verified and more representative two-dimensional (2D) mathematical model of directional solidification that can aid in the fundamental study of freezing of biological matter, in particular during 3D cryoprinting. The mathematical model was used to develop correlations between the freezing rates that a layer of an aqueous solution experiences during directional solidification and the various design parameters such as thickness of the sample and temperature gradients in the substrate. Results show that the freezing rates can be higher than those suggested by the previously used simplified 1D mathematical models. The results can be used for developing simplified models of 3D cryoprinting. In addition, the results suggest that many experimental studies on directional solidification of aqueous solutions and biological matter may require readjustment of analysis, in view of these findings.
Toward Automated Vehicle Control Beyond the Stability Limits: Drifting Along a General Path
Authors: Goh Jonathan Y. , Goel Tushar , Christian Gerdes J. 
Published: October 2019

Abstract
Professional drivers in drifting competitions demonstrate accurate control over a car's position and sideslip while operating in an open-loop unstable region of state-space. Could similar approaches help autonomous cars contend with excursions past the stable handling limits, thereby improving overall safety outcomes? As a first step toward answering that question, this paper presents a novel controller framework for automated drifting along a path. The controller is derived for the general case, without reference to a nearby equilibrium point. This leads to the physically insightful result that one can use the rotation rate of the vehicle's velocity vector to track the path, while simultaneously using the yaw acceleration to stabilize sideslip. Nonlinear model inversion, in concert with low-level wheelspeed control, is then used to achieve these required state derivatives over a broad range of conditions. Experiments on MARTY, a modified 1981 DMC DeLorean, demonstrate excellent tracking of a path with varying curvature, speed, and sideslip. Comparisons to a test run without wheelspeed control highlight the importance of accounting for the rear saturated-tire wheelspeed dynamics.
Design and Analysis of a Swashplate Control System for an Asymmetric Axial Piston Pump
Authors: He Wei , Huang Jia-Hai , Hao Hui-Min , Quan Long , Ji Shuai-xu , Zhao Bin 
Published: October 2019

Abstract
Based on the previously developed fixed-displacement asymmetric axial piston pump, a variable displacement asymmetric axial piston pump (VDAAPP) with three independent suction/delivery ports is proposed. A basic linear model of VDAAPP is established to get open-loop bode diagram. Based on open-loop Bode diagram features and design requirements, P-controller is determined for VDAAPP. Then VDAAPP's performance is investigated by advanced modeling environment for performing simulations of engineering systems (AMESim) and automatic dynamic analysis of mechanical systems (ADAMS) joint simulation, and some key design parameters are obtained. Next, a VDAAPP prototype with a maximum displacement of 40 cc/rev is designed and manufactured, ratio of flow rates at ports A, B and T is 1:0.6:0.4. Due to hard limitations of the test bench, the performance only under the conditions of the opposite passive loads is tested. Preliminary test results indicate that VDAAPP prototype works normally and meets the design requirements for flow ratio, and the maximum rise time of the test pressure is about 0.32 s. However, due to special design of VDAAPP valve plate, the swash plate torque severely limits system dynamic response. Therefore, an improved swashplate control system based on asymmetric-valve-controlled asymmetric-piston scheme is presented as well, it is found to be an effective way to suppress the negative impact of swash plate torque on system dynamic performance. This provides a direction for the optimization of the swashplate control system for asymmetric axial piston pumps in the future.
Nonlinear Kalman Filtering With Expensive Forward Models Via Measure Change
Authors: Burrows Brian J. , Allaire Douglas 
Published: October 2019

Abstract
Filtering is a subset of a more general probabilistic estimation scheme for estimating the unobserved parameters from the observed measurements. For nonlinear, high speed applications, the extended Kalman filter (EKF) and the unscented Kalman filter (UKF) are common estimators; however, expensive and strongly nonlinear forward models remain a challenge. In this paper, a novel Kalman filtering algorithm for nonlinear systems is developed, where the numerical approximation is achieved via a change of measure. The accuracy is identical in the linear case and superior in two nonlinear test problems: a challenging 1D benchmarking problem and a 4D structural health monitoring problem. This increase in accuracy is achieved without the need for tuning parameters, rather relying on a more complete approximation of the underlying distributions than the Unscented Transform. In addition, when expensive forward models are used, we achieve a significant reduction in computational cost without resorting to model approximation.
Impact of a Plate on an Asymmetric Water Wedge
Authors: Wen Xueliang , Liu Peiqing , Qu Qiulin , Hu Tianxiang 
Published: October 2019

Abstract
The impacts of a plate on an asymmetric water wedge with constant and varying speeds are studied in this paper by considering the fluid to be incompressible, inviscid, and weightless; the effect of surface tension to be negligible; and the flow to be irrotational. A similarity solution for an impact with a constant speed is derived with the help of Wagner's function and the Schwarz–Christophel mapping technique and then numerically solved by employing an iterative method. An approximate solution is derived for the impact with a varying speed satisfying a power law in time based on the computational fluid dynamics (CFD) results with the volume of fluid (VOF) method. The approximate solution can provide an explicit expression for the pressure acting on the plate. The CFD validation shows that the pressure expression can also be applicable to other cases in which the speed of the plate is not a power law in time.
An Area-Depth Approximation Model of Microdrilling on High-Density Polyethylene Soft Films Using Pulsed Laser Ablation
Authors: Ravi-Kumar Sandeep , Zhang Xiao , Lies Benjamin , Jiang Liangkui , Qin Hantang 
Published: October 2019

Abstract
Microdrilling based on laser ablation has been widely applied for manufacturing micro-/nanofeatures on different materials as a noncontact thermal removal approach. It has the advantages of high aspect ratio manufacturing capability and reduced surface damage. However, laser ablation is a complicated process that is challenging to model. In this paper, a standardized modeling procedure was demonstrated to predict the area and depth of laser ablation based on experimental study and simulation validation. A case study was conducted where microdrilling of high-density polyethylene (HDPE) was investigated using a 1064 nm nanosecond pulsed laser. Blind microholes were fabricated on the HDPE samples by ablating under different laser powers and numbers of pulses. Gain factors were defined and determined by the experimental data. A quantitative area-depth approximation model was formulated based on the gain factors. A comparison of the measured and the simulated results of microholes presented average 96.5% accuracy for the area and 85.7% for the depth. This research provided a simple but effective approach to predict dimensions of microholes on various substrates using laser ablation under different laser powers and the numbers of pulses, which could pave the way for development and modeling of laser ablation on polymers.
<p class="Body"><strong>A new genus, new species and a new record of the family Pygmephoridae (Acari: Heterostigmata) associated with <em>Microcerotermes </em></strong><strong><em> </em></strong><strong><em>parvus</em></strong><strong> (</strong><strong>Haviland</strong><strong>) (Isoptera: Termitidae) from South Africa</strong></p>
Authors: Khaustov Alexander A. , Hugo-Coetzee Elizabeth A. , Ermilov Sergey G. 
Published: October 2019

A new genus and species of termitophilous pygmephorid mites, Pseudoluciaphorus tuberosus gen. nov. and sp. nov. (Acari: Prostigmata: Pygmephoridae), associated with termites, Microcerotermes parvus (Haviland) (Isoptera: Termitidae) are described from South Africa. Luciaphorus perniciosus Rack is recorded from Africa for the first time. Images of phoretic females of L. perniciosus phoretic on workers and soldiers of Microcerotermes parvus are provided.
Butcher Ridge igneous complex: A glassy layered silicic magma distribution center in the Ferrar large igneous province, Antarctica
Authors: Nelson Demian A. , Cottle John M. , Schoene Blair 
Published: October 2019

Abstract
The Butcher Ridge igneous complex, Antarctica, is an ∼6000 km3 hypabyssal silicic intrusion containing rhythmically layered glassy rocks. Baddeleyite U-Pb geochronologic analysis on a sample of the Butcher Ridge igneous complex yielded an age of ca. 182.4 Ma, which confirms that it was emplaced synchronously with the Ferrar large igneous province. Rocks of the Butcher Ridge igneous complex vary from basaltic andesite to rhyolite, and so the inferred volume of the Butcher Ridge igneous complex makes it the most voluminous silicic component of the Ferrar large igneous province. Major-element, trace-element, and isotopic data combined with binary mixing, assimilation-fractional crystallization (AFC), and energy-constrained AFC models are consistent with formation of Butcher Ridge igneous complex silicic rocks by contamination of mafic Ferrar parental magma(s) with local Paleozoic plutonic basement rocks. Field and petrographic observations and evidence for alkali ion exchange suggest that the kilometer-long, meter-thick enigmatic rhythmic layering formed as a result of secondary hydration and devitrification of volcanic glass along parallel fracture networks. The regularity and scale of fracturing/layering imply a thermally driven process that occurred during shallow emplacement and supercooling of the intrusion in the upper crust. We suggest that layering observed in the Butcher Ridge igneous complex is analogous to that reported from terrestrial and Martian cryptodomes, and therefore it is an ideal locality at which to study layering processes in igneous bodies.
A randomized comparison between Accuro and palpation-guided spinal anesthesia for obese patients undergoing orthopedic surgery
Authors: Ghisi Daniela , Tomasi Marco , Giannone Sandra , Luppi Alessandra , Aurini Lucia , Toccaceli Letizia , Benazzo Andrea , Bonarelli Stefano 
Published: October 2019

BackgroundAlthough obese patients benefit from neuraxial anesthesia, technical difficulties often discourage its use. The current randomized trial compared Accuro, a hand-held, battery-operated ultrasound (US) device, and conventional palpation for spinal anesthesia in obese patients undergoing orthopedic surgery. We hypothesized that Accuro would decrease the number of needle redirections.MethodsWe enrolled 130 men and women with a body mass index ≥30 kg/m2, scheduled for lower limb surgery under spinal block. Patients were randomized either to the Control group (group C: spinal block after palpation of cutaneous landmarks) or to the Accuro group (group A: preprocedural US scan with Accuro to identify the needle insertion point). The procedural time, the number of skin passes and of needle redirections, the occurrence of failure and adverse events were recorded.ResultsNinety-nine patients completed the study. Patients in group Accuro showed a median (IQR) number of redirections of 3 (0–9) and a median (IQR) number of needle passes through the skin of 1 (1-2) versus 6 (1-16) and 1 (1-3), respectively, in group Control (p=0.008, p=0.019). The performance time was 558±232 s in group Accuro versus 348±255 s in group Control (p<0.001). There were no intergroup differences in terms of failed blocks and adverse events.ConclusionsThe use of Accuro reduced the number of needle redirections and passes through the skin when performing spinal anesthesia, but required a longer procedural time.Trial registration numberClinicalTrials.gov registry (NCT03075488).
Ultrasound-guided L5 dorsal ramus block: validation of a novel technique
Authors: Etheridge John-Paul B , De Villiers Frederick , Venter Jan , Squire Pam , Farnquist Brenda , Finlayson Roderick J 
Published: October 2019

BackgroundAlthough the value of ultrasound-guided (USG) lumbar medial branch blocks (MBB) has previously been examined in several clinical trials, blocking the L5 dorsal ramus (DR) remains a technical challenge and we sought to examine the accuracy of a novel technique targeting this level.MethodsIn this prospective cohort study, 115 patients scheduled for an L4 MBB and L5 DR block underwent an ultrasound scan to assess their lower spine sonoanatomy. Subjects in whom the necessary landmarks could be visualized underwent a USG L5 DR block using a pivot technique, which involved redirecting a needle from its position on the L5 transverse process after an L4 MBB. Success was determined by a blinded observer who examined the contrast distribution on postprocedural X-ray images. In addition to the final needle position, performance time, the number of needle passes, and any complication were recorded.ResultsA total of 100 patients had a USG block and 15 patients (13%) were excluded because of poor landmark visibility. The latter group presented a significantly higher body mass index (38.90±7.50 vs 26.31±4.25 kg/m2, p=0.004). A total of five failures were noted (95% success rate), this included three patients with transitional anatomy in whom needles were placed at the wrong level and two cases of incomplete contrast coverage possibly related to the partial intravascular injection. Performance time was 153.93±41.56 s and the median number of needle passes was 2 (range 4). No significant complications were noted.ConclusionThe pivot technique provides a reliable approach for USG L5 DR ramus blocks.Trial registration numberNCT03805906