bluuebunny/crossref_metadata_2025_split huggingface dataset:
Estimation of Body Fluid Status by Fluid Balance and Body Weight in Critically Ill Adult Patients: A Systematic Review
Authors: Davies Hugh , Leslie Gavin , Jacob Elisabeth , Morgan David 
Published: December 2019

AbstractBackgroundThe charting of daily fluid balances and measurement of body weight changes are two noninvasive methods commonly used in the intensive care unit for estimating body fluid status. The determination of body fluid status plays an important role in the management of critically ill patients where aggressive fluid resuscitation is often required. This can adversely affect patient outcomes if changes in fluid distribution are not detected early in patients who are susceptible to fluid overload.AimTo synthesize the best available evidence on the accuracy of daily fluid balance charting compared with the measurement of body weight for the estimation of body fluid status in critically ill adult patients.MethodsThe review considered studies that investigated the accuracy of charting daily fluid balances or changes in body weight measurements or used both noninvasive methods in the estimation of body fluid status. The search sought to identify published, English language studies from 1980 until February 2018. Databases searched includedMEDLINE,CINAHL,EMBASE,TRIP, Scopus,TROVE, ProQuest Dissertations, Australian and New Zealand Trials Registry, and Cochrane Central Register of Clinical Trials. Three reviewers independently assessed retrieved studies that matched inclusion criteria using standardized critical appraisal instruments.ResultsThe review included 13 cohort studies. Effectiveness of daily fluid balance charting was affected by inaccuracies observed in seven studies. Inability to obtain consecutive daily body weight measurements reduced the accuracy of monitoring changes in five studies. Seven studies found measurement of daily fluid balance inconsistent with changes in body weight.Linking Evidence to ActionThe accuracy of charting fluid balance is suspect. Measurement of body weight is hard to accomplish. A combination of the two commonly used methods is more likely to be effective in estimating body fluid status than reliance on one single approach.
Pacemaker function and neural responsiveness of subserosal interstitial cells of Cajal in the mouse colon
Authors: Drumm Bernard T. , Rembetski Benjamin E. , Messersmith Katelyn , Manierka Marena S. , Baker Salah A. , Sanders Kenton M. 
Published: December 2019

Key points
Rhythmic action potentials and intercellular Ca2+ waves are generated in smooth muscle cells of colonic longitudinal muscles (LSMC).
Longitudinal muscle excitability is tuned by input from subserosal ICC (ICC‐SS), a population of ICC with previously unknown function.
ICC‐SS express Ano1 channels and generate spontaneous Ca2+ transients in a stochastic manner.
Release of Ca2+ and activation of Ano1 channels causes depolarization of ICC‐SS and LSMC, leading to activation of L‐type Ca2+ channels, action potentials, intercellular Ca2+ waves and contractions in LSMC.
Nitrergic neural inputs regulate the Ca2+ events in ICC‐SS.
Pacemaker activity in longitudinal muscle is an emergent property as a result of integrated processes in ICC‐SS and LSMC.
AbstractMuch is known about myogenic mechanisms in circular muscle (CM) in the gastrointestinal tract, although less is known about longitudinal muscle (LM). Two Ca2+ signalling behaviours occur in LM: localized intracellular waves not causing contractions and intercellular waves leading to excitation‐contraction coupling. An Ano1 channel antagonist inhibited intercellular Ca2+ waves and LM contractions. Ano1 channels are expressed by interstitial cells of Cajal (ICC) but not by smooth muscle cells (SMCs). We investigated Ca2+ signalling in a novel population of ICC that lies along the subserosal surface of LM (ICC‐SS) in mice expressing GCaMP6f in ICC. ICC‐SS fired stochastic localized Ca2+ transients. Such events have been linked to activation of Ano1 channels in ICC. Ca2+ transients in ICC‐SS occurred by release from stores most probably via inositol trisphosphate receptors. This activity relied on influx via store‐operated Ca2+ entry and Orai channels. No voltage‐dependent mechanism that synchronized Ca2+ transients in a single cell or between cells was found. Nitrergic agonists inhibited Ca2+ transients in ICC‐SS, and stimulation of intrinsic nerves activated nitrergic responses in ICC‐SS. Cessation of stimulation resulted in significant enhancement of Ca2+ transients compared to the pre‐stimulus activity. No evidence of innervation by excitatory, cholinergic motor neurons was found. Our data suggest that ICC‐SS contribute to regulation of LM motor activity. Spontaneous Ca2+ transients activate Ano1 channels in ICC‐SS. Resulting depolarization conducts to SMCs, depolarizing membrane potential, activating L‐type Ca2+ channels and initiating contraction. Rhythmic electrical and mechanical behaviours of LM are an emergent property of SMCs and ICC‐SS.
Performance Assessment of Parallel Connected Ranque–Hilsch Vortex Tubes Using Nitrogen, Oxygen, and Air With Brass and Polyamide Nozzles: An Experimental Analysis
Authors: Kirmaci Volkan 
Published: December 2019

Abstract
In this study, heating and cooling performances of two vortex tubes connected in parallel using different working fluids were compared. In experimental studies, oxygen, nitrogen, and air were used as working fluids in counterflow Ranque–Hilsch vortex tube (RHVT) and performance evaluation was performed. Nozzles made of polyamide and brass are used, and the number of these nozzles is 2, 4, and 6. Compressed working fluids were used to operate the vortex tube system at different inlet pressure values varying from 150 kPa to 600 kPa with 50 kPa increment. The geometric characteristics of the vortex tube are the length of the hot tube and the diameter of the orifice, which are 100 mm and 7 mm, respectively. Experiments were performed with the hot flow outlet valve fully open. The thermodynamic performance of the parallel connected vortex tube system was determined by performing exergy analysis. As a result of experimental studies, the highest performance of parallel connected RHVT system was obtained when nitrogen was used as a working fluid with brass-six-nozzle at 600 kPa.
Turbocharger Speed Monitoring Based on Vibration Measurements for Diesel Engine Management
Authors: Chiatti Giancarlo , Chiavola Ornella , Palmieri Fulvio 
Published: December 2019

Abstract
Demanding legislation on exhaust emissions and fuel consumption has led great attention to on board control algorithms able to optimize the combustion process in terms of efficiency and pollutants emissions production.
Dealing with turbocharged engines, the thermo and fluid dynamic conditions of the exhaust gas are responsible for the turbine rotation; its speed has demonstrated to be related to the combustion process and can be used for the combustion monitoring.
This work presents a methodology in which the instantaneous turbocharger speed is obtained by the processing of the signal from an accelerometer mounted on the compressor housing.
Experimental tests have been carried out on a small water-cooled, two cylinder, common rail diesel engine installed in the Laboratory of the Engineering Department at ‘ROMA TRE’ University. The methodology has been applied to the signals acquired during steady state and transient tests. The comparison between the estimations provided by the accelerometer and the values obtained by direct measurements highlighted the accuracy of the predictions thus demonstrating the suitability of the accelerometer to be used as feedback signal in algorithms for the engine management in order to maintain the combustion effectiveness in spite of aging and degradation of components, variations of fuel properties.
Innovative Instrumented Sliding Bearings As a New Approach to On-Board Bearing Monitoring
Authors: Breiteneder Thomas , Schubert-Zallinger Claudia , Wimmer Andreas , Vyštejn Jan , Hager Gunther , Schallmeiner Stefan 
Published: December 2019

Abstract
In addition to a further reduction in fuel consumption and emissions, the current focus of internal combustion engine development is on system integration of the engine and its components to ensure perfect engine operation and high engine performance over the entire service life of the engine. Extensive sensor application allows acquisition, storage and intelligent processing of numerous engine parameters in digital engine control systems. Intelligent software platforms are increasingly being used to fully exploit the data generated by sensor systems and ensure optimal engine operation. This paper deals with new concepts for measuring physical quantities that are characteristic of sliding bearings. It describes the development of a flexible and multifunctional sensor technology for real-time measuring of temperature and pressure as well as the signal transfer and data acquisition from moving parts to outside the engine.
The sensor technology required for such a system must meet the challenges of defining a quickly responding method that captures the measured variable as close to the bearing surface as possible in order to detect bearing failures in advance. The system must be able to withstand the high temperatures and mechanical loads inside the engine. In addition, fast wireless data transfer of signals acquired from moving components such as conrod bearings is necessary. A highly flexible sensor package based on thin-film technology was developed to meet these requirements. The sensor is integrated into the bearing shell and has the potential to be employed in series application. A robust telemetry unit able to withstand harsh environmental conditions such as high temperature and extremely high centrifugal forces was developed that transfers the measured data to engine ECU or other external devices. At the same time, transmission rate, distances and power demand are subject to stringent requirements.
To create a comparative basis for further verification of bearings with thin film sensor technology and to gain insight into the temperature distribution in the bearing gap, measurements with conventional sensor technology that assesses temperatures directly inside the lubrication gap were undertaken on a bearing test rig as well as on a multicylinder heavy duty diesel truck engine. The results of these investigations also provide a fundamental understanding of the temperature distribution in the bearing gap for crankshaft as well as for conrod bearings. The results of ongoing investigations will include a validation of the new temperature measurement method based on thin film technology under real engine conditions.
A Literature Review of NOx Formation Kinetics and a Prediction Method for Lean-Burn, Two-Stroke Natural Gas Engines
Authors: Linker Taylor F. , Patterson Mark , Beshouri Greg , Bajwa Abdullah U. , Jacobs Timothy J. 
Published: December 2019

Abstract
The increased production of natural gas harvested from unconventional sources, such as shale, has led to fluctuations in the species composition of natural gas moving through pipelines. These variations alter the chemical properties of the bulk gas mixture and, consequently, affect the operation of pipeline compressor engines which use the gas as fuel. Among several possible ramifications of these variations is that of unacceptably high engine-out NOx emissions. Therefore, engine controller enhancements which can account for fuel variability are necessary for maintaining emissions compliance. Having the means to predict NOx emissions from a field engine can inform the development of such control schemes.
There are several types of compressor engines; however, this study considers a large bore, lean-burn, two-stroke, integral compressor engine. This class of engine has unique operating conditions which make the formation of engine-out NOx different from typical automotive spark-ignited engines. For this reason, automotive-based methods for predicting NOx emissions are not sufficiently accurate. In this study, an investigation is performed on the possible NO and NO2 formation pathways which could be contributing to exhaust emissions. Additionally, a modeling method is proposed to predict engine-out NOx emissions using a 0-D/1-D model of a Cooper-Bessemer GMWH-10C compressor engine. Predictions are achieved with GRI-Mech3.0, a natural gas combustion mechanism, which allows for simulated formation of NOx species. The implemented technique is tuned using experimental data from a field engine to better predict emissions over a range of engine operating conditions. Tuning the model led to acceptable agreement across operating points varying in both load and trapped equivalence ratio.
A New Single-Zone Multi-Stage Scavenging Model for Real-Time Emissions Control in Two-Stroke Engines
Authors: Bajwa Abdullah U. , Patterson Mark , Linker Taylor , Jacobs Timothy J. 
Published: December 2019

Abstract
Gas exchange processes in two-stroke internal combustion engines, i.e. scavenging, remove exhaust gases from the combustion chamber and prepare the fuel-oxidizer mixture that undergoes combustion. A non-negligible fraction of the mixture trapped in the cylinder at the conclusion of scavenging is composed of residual gases from the previous cycle. This can cause significant changes to the combustion characteristics of the mixture by changing its composition and temperature, i.e. its thermodynamic state. Thus, it is vital to have accurate knowledge of the thermodynamic state of the post-scavenging mixture to be able to reliably predict and control engine performance, efficiency and emissions.
Several simple-scavenging models can be found in the literature that — based on a variety of idealized interaction modes between incoming and cylinder gases — calculate the state of the trapped mixture. In this study, boundary conditions extracted from a validated 1-D predictive model of a single-cylinder two-stroke engine are used to gauge the performance of four simple scavenging models. It is discovered that the assumption of thermal homogeneity of the incoming and exiting gases is a major source of inaccuracy. A new non-isothermal multi-stage single-zone scavenging model is thus, proposed to address some of the shortcomings of the four models. The proposed model assumes that gas-exchange in cross-scavenged two-stroke engines takes place in three stages; an isentropic blowdown stage, followed by perfect-displacement and perfect-mixing stages. Significant improvements in the trapped mixture state estimates were observed as a result.
Boiling Heat Transfer Using Spatially-Variant and Uniform Microporous Coatings
Authors: Pham Quang N. , Suh Youngjoon , Shao Bowen , Won Yoonjin 
Published: December 2019

Abstract
Two-phase thermal management offers cooling performance enhancement by an order of magnitude higher than single-phase flow due to the latent heat associated with phase change. Among the modes of phase-change, boiling can effectively remove massive amounts of heat flux from the surface by employing structured or 3D microporous coatings to significantly enlarge the interfacial surface area for improved heat transfer rate as well as increase the number of potential sites for bubble nucleation and departure. The bubble dynamics during pool boiling are often considered to be essential in predicting heat transfer performance, causing it to be a field of significant interest. While prior investigations seek to modulate the bubble dynamics through either active (e.g., surfactants, electricity) or passive means (e.g., surface wettability, microstructures), the utilization of an ordered microporous architecture to instigate desirable liquid and vapor flow field has been limited. Here, we investigate the bubble dynamics using various spatial patterns of inverse opal channels to induce preferential heat and mass flow site in highly-interconnected microporous media. A fully-coated inverse opal surface demonstrates the intrinsic boiling effects of a uniform microporous coating, which exhibits 156% enhancement in heat transfer coefficient in comparison to the polished silicon surface. The boiling heat transfer performances of spatially-variant inverse opal channels significantly differ based on the pitch spacings between the microporous channels, which dictate the bubble coalescent behaviors and bubble departure characteristics. The elucidated boiling heat transfer performances will provide engineering guidance toward designing optimal two-phase thermal management devices.
Thermomechanical Stress and Warpage Augmentation Using Auxetic Features in Electronic Design
Authors: Montazeri Mahsa , Harris John , Huitink David R. , Venkatanarayanan Adithya , Ang Simon S. 
Published: December 2019

Abstract
One of the leading contributors to assembly and reliability issues in electronic packaging arises from warpage and interfacial stresses stemming from coefficient of thermal expansion (CTE) mismatch of the interfacing components. Trends toward miniaturizing and increasing density of the electronic packages exacerbate the assembly problems, leading to issues such as die cracking and board level assembly yield loss. One potential solution may be found in the inclusion of auxetic structures, which demonstrate negative Poisson’s ratio through re-entrant geometries, which has been investigated for use in augmented structural mechanics for impact energy absorption. Because of the unique structural design, auxetics become thicker perpendicularly under an applied tensile load, unlike typical material loading responses. This interesting behavior has opportunity for integration into electronic packages for stress mitigation under thermal cycling since the structures can disrupt the typical expansion behavior. Here, auxetic trace geometries and structures were evaluated in various packaging implementations (die and substrate level) for warpage and stress reduction under thermal cycling conditions. By replacing standard Manhattan-style layouts and power and ground plane features with re-entrant trace geometries, reductions in thermomechanically induced interfacial stresses were observed, in addition to considering heat spreading properties within a package. Herein, deformation of silicon chip with addition of raised re-entrant Evans auxetics and raised ellipse shape auxetic traces as well as deformation of direct bonded copper (DBC) substrate with and without re-entrant auxetic patterned pads are estimated and compared using Finite Element Analysis (FEA) in ANSYS software. To demonstrate the benefits of passive auxetic traces, a planar transformer with re-entrant Evans auxetic patterns on PCB layers has been examined under full-load operating condition and compared with a traditionally patterned transformers. A better thermal distribution and lower maximum temperature in the device are achieved by including auxetic patterned features. FEA simulation results also show stress reduction in windings and lower deformation in PCB layers. Inclusion of auxetic structures in passive metal deposition layers which are not part of the circuit is shown to reduce maximum stress and warp deflection, as well as improve thermal gradient distribution and reduce overall temperature for 2D planar and 3D stacked packages. Consequently, use of auxetic features may extend package reliability significantly.
Quantitative Characterization of Sapphire and Silicon Nitride for Space Applications Circuit Subassemblies Using Cryogenic Cycling
Authors: Lovelace Kirsten , Smith Sonya 
Published: December 2019

Abstract
This research investigates the effects of thermal cycling from room to cryogenic temperatures (300K–4K) on the thermal expansion coefficient of two ceramic substrates of Silicon Nitride (Si3N4) and alpha-Alumina/Sapphire (α-Al2O3). Due to the shortage of available data, a comparative study with reference materials, Copper, AISI Carbon Steel 1008 and Molybdenum, are compared to the National Institute of Standards and Technology (NIST) property data as a proof of concept. Accurate thermal contraction data of materials at low temperatures are important in material selection and thermal design of engineered systems, such as, space electronic devices. Thermal expansion mismatch causes substantial problems in space electronic device reliability because of the various stresses imposed on the joint materials undergoing extreme thermal cycles. Theory supports the advantage of utilizing Sapphire (Al2O3) and Silicon Nitride (Si3N4) within microchip configuration. However, there is limited data available that confidently supports this assertion beyond theory. An electro-mechanical method for in-situ strain measurements is presented as a tool to characterize thermomechanical behavior of Sapphire and Silicon Nitride at temperatures below 50 K. The calculated coefficient of thermal expansion for silicon nitride is 1.35 · 10−6 1/K and 0.994 · 10−6 1/K for sapphire at 5.7 K. The results from this validation have a mean error percentage of less than 6 %.
Fabrication Steps and Thermal Modeling of Three-Dimensional Asynchronous Field Programmable Gate Array (3D-AFPGA)
Authors: Carroll Robert , Gutierrez Carlos , Choobineh Leila , Geer Robert 
Published: December 2019

Abstract
Field Programmable Gate Arrays (FPGA) are integrated circuits (ICs) which can implement virtually any digital function and can be configured by a designer after manufacturing. This is beneficial when dedicated application-specific runs are not time or cost-effective; however, this flexibility comes at the cost of a substantially higher interconnect overhead. Three-dimensional (3D) integration can offer significant improvements in the FPGA architecture by stacking multiple device layers and interconnecting them in the third or vertical dimension, through a substrate, where path lengths are greatly reduced. This will allow for a higher density of devices and improvements in power consumption, signal integrity, and delay. Further, it facilities heterogeneous integration where additional functionalities can be incorporated into the same package as the FPGA, such as sensors, memories, and RF/analog or photonic chips, etc. Traditionally, devices have always been laid out in a planar format. 3D integration is an architecture wherein multiple layers of planar devices are stacked and interconnected using through silicon vias (TSVs) in the vertical direction.
This work will specifically detail the development of a processing and fabrication route for a three-dimensional asynchronous field programmable gate array (3D-AFPGA) design based on an extension of preexisting 2D-FPGA tile designs. Since thermal management of 3D-AFPGA is important, numerical simulations performed to predict the temperature distribution and avoid the maximum junction temperature. The numerical thermal modeling for predicting the equivalent thermal conductivity in every layer and three-dimensional temperature fields in the 3D-AFPGA are developed and discussed.