bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Conductive Cooling Scheme for Bone Augmentation of the Proximal Femur With PMMA: An Experimental and Finite Element Study
Authors: Bakhtiarinejad Mahsan , Farvardin Amirhossein , Chamani Alireza , Armand Mehran 
Published: January 2020

Abstract
The rate of one-year mortality after osteoporotic hip fracture in elderly is reported to be more than 20%. Hip augmentation using polymethylmethacrylate (PMMA) is an alternative preventive approach for patients at the highest risk of osteoporotic fracture. Excessive injection volumes of PMMA however may introduce the risk of thermal osteonecrosis. We have previously proposed a Finite element (FE) simulation to estimate the bone temperature elevations after cement injection in three key locations and demonstrated an agreement between the simulation results and the temperature measurements during the experiment. Previous study showed that the maximum temperature-rise measured at the hip surface is 10°C. The aim of this study is to introduce a cooling approach to reduce the PMMA’s curing temperature after cement injection during hip augmentation. For this purpose, we perform a conductive cooling experiment with a metallic K-wire attached to an ice-water bath. We also create a finite element simulation model for the proposed cooling system to estimate the peak temperature reduction and compare the simulation results with experimental data. Simulation results demonstrate the decrease of 80% of peak curing temperature during PMMA polymerization; similarly, sawbone experiments also show that on average the peak temperature has been reduced 64% when cooling system is integrated to the hip augmentation procedure.
Experimental Study of the Effect of Nanoparticle Concentration on Thermo-Physical Properties of Molten Salt Nanofluids
Authors: Tiznobaik Hani , Shin Donghyun 
Published: January 2020

Abstract
Increased in thermo-physical properties of molten salt nanofluids have been reported. These findings makes molten salts nanofluids one of the most promising thermal energy storage media. One of the main application of these types of materials are in concentrated solar power plants. In this study, an investigation is performed on nanofluids specific heat capacity mechanisms in order to provide a reasonable description of the specific heat capacity enhancement of nanofluids. Then, a comprehensive experiments are performed on the effects of nanoparticles concentration on the specific heat capacity and materials characterization of molten salt nanofluids. This study is performed to analyze the optimum amount of nanoparticle and find the way to maximize the effects of nanoparticle on thermophysical properties of molten slat. Different molten salts nanofluids with varying nanoparticles concentration were synthesized. The specific heat capacities of mixtures were measured by a modulated scanning calorimeter. Moreover, the material characterization analyses were performed using scanning electron microscopy to investigate the micro-structural characterization of different nanofluids.
Performance Improvements of Krylov Subspace Methods in Numerical Heat Transfer and Fluid Flow Simulations
Authors: Blomquist Matthew , Mukherjee Abhijit 
Published: January 2020

Abstract
In recent years, advancements in computational hardware have enabled massive parallelism that can significantly reduce the duration of many numerical simulations. However, many high-fidelity simulations use serial algorithms to solve large systems of linear equations and are not well suited to exploit the parallelism of modern hardware. The Tri-Diagonal Matrix Algorithm (TDMA) is one such example of a serial algorithm that is ubiquitous in numerical simulations of heat transfer and fluid flow. Krylov subspace methods for solving linear systems, such as the Bi-Conjugate Gradients (BiCG) algorithm, can offer an ideal solution to improve the performance of numerical simulations as these methods can exploit the massive parallelism of modern hardware.
In the present work, Krylov-based linear solvers of Bi-Conjugate Gradients (BCG), Generalized Minimum Residual (GMRES), and Bi-Conjugate Gradients Stabilized (BCGSTAB) have been incorporated into the SIMPLER algorithm to solve a three-dimensional Rayleigh-Bénard Convection model. The incompressible Navier-Stoke’s equations, along with the continuity and energy equations, are solved using the SIMPLER method. The computational duration and numerical accuracy for the Krylov-solvers are compared with that of the TDMA. The results show that Krylov methods can improve the speed of convergence for the SIMPLER method by factors up to 7.7 while maintaining equivalent numerical accuracy to the TDMA.
Miniaturized Ultrasound Transducer Composed of a Composite of Multiple Piezoelectric Stacks
Authors: Kim Howuk , Wu Huaiyu , Goel Leela , Jiang Xiaoning 
Published: January 2020

Abstract
This paper aims to develop a miniaturized ultrasound transducer for intravascular thrombolysis, which requires a transducer with high mechanical index (&gt; 0.3) and a long focal distance (&gt; 2.0 mm). To meet this need, a composite of a multi-pillar piezo stack (MPPS) transducer was designed and fabricated by using PZT-4, conductive epoxy, soft elastomer, and a metallic concave lens. The simulation results showed the predominant extensional mode at around 0.92 MHz. The −6 dB focal distance was elongated by 150% from that of the common single-pillar piezo stack (SPPS) transducer with the same aperture. The acoustic pressure was improved by 8.2 dB at the focal zone. Next, the experimental results showed the peak-to-negative pressure of 1.92 MPa under 120 Vpp input, which was sufficient to cause the inertial cavitation of microbubble contrast agents. The −6 dB focal distance reached up to 3.4 mm which was a significant improvement compared to the conventional SPPS transducer. The developed intravascular transducer will be employed for the microbubble-mediated ultrasound thrombolysis to reduce the treatment time.
Design of Bolted Preload Electromechanical Impedance Monitoring Device for CubeSat
Authors: Zhang Zihan , Li Jiacheng , Du Fei , Xu Chao 
Published: January 2020

Abstract
With the rapid development of long-term orbiting spacecraft, deep space exploration and reusable carriers, spacecraft structures increasingly require safety and reliability. During the long-term service of the spacecraft structure, the bolts are prone to loosening. Electromechanical impedance (EMI) method is sensitive to bolt loosening. This paper developed a small integrated, low-power EMI monitoring device for CubeSat to detect bolt loosening, since CubeSat is low cost and has a long-time service in the orbit. The monitoring device is a two-layer structure of 0.6U. The upper layer is the experimental specimen layer. The other layer is the impedance measurement layer which can measure and transfer the impedance and temperature information. This layer consists of impedance measurement module, channel selection module, microprocessor module, communication module and power management module. The impedance results obtained by the monitoring device matched well with these by impedance analyzer. Besides, the influence of temperature on impedance measurement was studied, and two methods of compensating impedance curves were compared. Finally, the bolt loosening experiment was performed on one bolted beam of the specimen at different temperatures. The results show that, combined with the temperature compensation of the real part curve of the impedance, the bolt loosening can be clearly distinguished from the healthy condition. This monitoring device and temperature compensation method are expected to be applied on the CubeSat.
Direct Pressure Measurement and Flow Visualization of Cavitation in a Converging-Diverging Nozzle
Authors: Gallman Benjamin , Beck B. Terry , Hosni Mohammad H. 
Published: January 2020

Abstract
While normally certain unwanted phenomena are to be avoided, cavitation has useful engineering applications. Specifically, it can be used as to create cooling potential in a novel non-vapor compression refrigeration process. Cavitation occurs when the pressure of the working fluid (compressed liquid) drops below the saturation pressure. Since the cavitation (flash) results in an abrupt reduction in temperature, the working fluid can take in energy as heat from the surroundings during cavitation, which results in a cooling potential (refrigeration). In a converging-diverging nozzle, as the fluid passes through the throat the pressure decreases. If the pressure drops below the saturation pressure, cavitation can occur. The current research focuses on measuring the pressure nearby the cavitation front, and the associated pressure distribution within the two-phase region, in a converging diverging nozzle. A blow-down flow system was used to conduct measurements with water as the working fluid. The flow rate was measured with a rotameter and a Coriolis flow meter. The nozzle is a transparent 3D printed nozzle with an inlet diameter of 9.3 mm, throat diameter of 1.71 mm, and an outlet diameter of 9.3 mm. The upstream reservoir was kept at atmospheric pressure and was elevated above the level of the nozzle inlet. The downstream reservoir was evacuated to create a pressure difference that would drive fluid through the nozzle. The pressure distribution within the nozzle was measured using eight pressure transducers connected to the nozzle with 0.006” diameter taps, and a high-speed camera was used to capture flow visualization. The pressure distribution was measured for steady cavitating flow at several back pressures, and during an increasing flow rate to capture pressure changes during cavitation initiation. These results give direct pressure measurements during cavitating flow, along with the accompanying flow visualization. They should prove useful for furthering the understanding of the metastable fluid mechanics behavior of cavitating flows, and thereby contribute to the ability to ultimately maximize the cooling potential of the cavitation phenomena.
A Detachable Thermoelectric Generator As a Power Source for a 3G Camera Network Using a Steam Pipe As a Heat Source
Authors: Dell Robert , Petralia Michael Thomas , Pokharel Ashish , Gislason Gudmundur , Unnthorsson Runar 
Published: January 2020

Abstract
The author’s patented thermoelectric generator system uses a steam pipe as a heat source and ambient cooling in an exterior location at the Agricultural University of Iceland. This produces up to 7.2 watts (W) steady state using 6 thermoelectric modules.
The system has been powering a 3G webcam system since 2017 while it’s surplus power trickle charges 12 volt (V) batteries. New low power monitoring options originally developed for photovoltaic systems can be easily retrofitted for improved efficiency, additional and control options. The test results confirm the viability of a thermoelectric generator as power sources for security systems.
Modelling Stress Softening and Necking Phenomena in Double Network Hydrogels
Authors: Morovati Vahid , Saadat Mohammad Ali , Dargazany Roozbeh 
Published: January 2020

Abstract
Double network (DN) gels are three-dimensional polymer matrices formed by interpenetrating networks. In contrast to the conventional single-network gels, DN gels have significant toughness, which makes them a promising material for different biomedical and biological applications. However, DN gels show complicated inelastic behavior including the Mullins effect and necking instability. Despite extensive efforts on modelling different aspects of the damage process in gels, the micro-mechanical modelling of the mechanisms that lead to necking in DN gels remains to be a challenging task. Here, a constitutive model is proposed to understand and describe the mechanical behavior of DN gels based on statistical micro-mechanics of interpenetrating polymer networks. DN gels behavior is divided into three parts including pre-necking, necking, and hardening. The first network is dominant in the response of the gel in the pre-necking stage. The breakage of the first network to smaller network fractions (clusters) induces the stress softening observed in this stage. The interaction of both networks and the second network are also considered as main contributors to the response of gel in necking and hardening stages, respectively. The contribution of clusters decreases during the necking as the second network starts hardening. The numerical results of the proposed model are validated and compared by uni-axial cyclic tensile experimental data of DN gels.
Vibration Analysis of a Horizontal Partially Fluid-Filled Cylindrical Shell Considering Sloshing Effect of Free Surface
Authors: Pan Luyan , Zhu Xiang , Li Tianyun , Han Yueyang , Liang Xiaotian 
Published: January 2020

Abstract
The free and forced vibrations of a horizontal partially fluid-filled cylindrical shell with sloshing effect are studied based on the finite element method. The structure and inner fluid taking into account the sloshing effect of the free surface are simulated by the shell and acoustic elements respectively. The natural frequencies of sloshing fluid and shell structure are calculated simultaneously by the FEM. To verify the accuracy of the results, the shell’s natural frequencies are compared with published results. The effects of the structural parameters and fluid depth on the vibration of the coupled system are discussed. The natural frequencies of a sloshing fluid can be divided into low-frequency and high-frequency part, and the low-frequency part refers to the pressure fluctuation caused by the sloshing of the free surface, while the high-frequency part corresponds to the pressure fluctuation of the particles below the free surface. The thinner the shell thickness is, the lower the sloshing frequency of free surface and coupled modal frequency of the shell are. With the increase of the liquid depth, the natural sloshing frequency of the free surface increases slightly while the coupled modal frequency of the shell decreases. The impact of the free surface effect on the coupled vibration cannot be omitted when the shell’s natural frequencies are close to the sloshing frequencies.
Model-Based Resilience Assessment Framework for Autonomous Systems
Authors: Diaconeasa Mihai A. , Mosleh Ali , Morozov Andrey , Tai Ann T. 
Published: January 2020

Abstract
While automation technologies advance faster than ever, gaps of resilience capabilities between autonomous and human-operated systems have not yet been identified and addressed appropriately. To date, there exists no generic framework for resilience assessment that is applicable to a broad spectrum of domains or able to take into account the impacts on mission-scenario-level resilience from system-specific attributes. In the proposed framework, resilience is meant to describe the ability of a system, in an open range of adverse scenarios, to maintain normal operating conditions or to recover from degraded or failed states in order to provide anticipated functions or services to achieve mission success. The term resilience is introduced in relation with classical terms such as fault, error, failure, fault-tolerance, reliability, and risk. The proposed model-based resilience assessment framework is based on a resilience ontology that enables the use of system models into reliability and risk models for transparent, persistent, and up-to-date modeling and quantification. A SysML profile and associated OWL ontology are defined to enable the use of a range of resilience mechanisms into the design and operation of a system.
How to Establish Digital Thread Using 3D Factory
Authors: Ajay Holey , Shashank Alandikar 
Published: January 2020

Abstract
In a manufacturing assembly line scenario, factory layout is one of the most crucial information used by manufacturing, facility and factory automation engineers for planning purposes. It is important for manufacturing, facility and operations team to work with most up-to-date layout when product, process and operational information on the shop-floor is constantly changing. There are four elements which governs availability of a real-time layout, these are nothing but Product Design, Manufacturing Process Planning, Layout Planning and Shop-floor. The layout must accommodate these changes coming from product design, process updates and shop-floor modifications on real-time basis so that there is no confusion amongst the stakeholders while referring layout data for their planning purpose. If we talk about the impact on the layout because of product design and process design, it is hardly managed real-time due to the isolated systems to manage these data. The integration of product, process and plant (PPP) is becoming crucial to facilitate collaboration and shrink new product introduction lead time where as real-time update from the shop-floor changes is expected in the era of digital transformation. One of the reasons why the integration of product, process and plant (PPP) does not happen is multiple isolated systems used to maintain this data, there are also challenges to feed data back from the shop-floor because of the non-availability of the thread between these objects.
The paper is about how factory layout can be developed integrating product, process and plant (PPP) in a single dynamic environment and establish a digital thread between the product design, manufacturing process planning and factory layout to trigger real-time changes and facilitate digital twin of the factory. The methodology adopted here is to develop bill of material for manufacturing resources and align it with the product data management. This approach not only provides ability to maintain change control over resource objects but also helps in configuration management of the resource bill of material. The resources are grouped together as layout structure for the plant with each object required to manufacture the product. The detailed layout developed for the plant while integrating with product and process is used to establish connection with objects on the shop-floor through sensors and IOT (Internet of Things) devices to form digital twin. Such details added in layout which is So far there are no efforts to digitalize every information on the factory floor and able to generate Digital Twin of the factory by connecting physical objects with the digital objects. Paper will elaborate the approach to establish digital thread between PPP and how this can become foundation to drive digital twin of the factory.
Deformation and Energy Absorption of Steel Square Tubes With Optimized Shape Design
Authors: Liu Xiaofang , Fang Ziwen , Hong Haifeng , Wang Jianran , Liu Yanwen , Lu Peng , Xiu Ruixian 
Published: January 2020

Abstract
Square crush tubes have been widely used as impact energy absorbers in automotive and railway vehicles. In this paper, a square tube with vertical plates and dents has been designed to increase the controllability and stability of crash performance. Vertical plates are welded perpendicularly to the side walls of the tube, which increase the transverse stiffness and ensure the tube crashes in longitudinal direction under impact not in ideal axial direction. Dents have been put on the side walls near the front end of the tube to ensure the collapse always start from the front and progress gradually to the end. To validate the design, finite element analysis (FEA) and various experiments has been conducted and evaluated. Firstly, the numerical simulations were carried out using the software LS-DYNA. Then, four specimens were manufactured and tested. The crash velocity, tube deformation and impact force showed great agreement between the simulations and test results. The number of tubes, tube wall thickness, cross-section, trigger plates and dents arrangement can be adjusted to meet the requirements of different applications. In one application, the energy absorbing device with four crush tubes provided progressive controlled collapse with energy absorbing capacity of 1.22MJ and impact force less than 4450kN. This robust crush tube design has been successfully applied in multiple railway vehicles and also has the potential to be applied in other industries such as automotive vehicles.
Cavitation Number As a Function of Disk Cavitator Radius: A Numerical Analysis of Natural Supercavitation
Authors: Prichard Reid , Strasser Wayne , Eldredge Thomas 
Published: January 2020

Abstract
Due to the greater viscosity and density of water compared to air, the maximum speed of underwater travel is severely limited compared to other methods of transportation. However, a technology called supercavitation — which uses a disk-shaped cavitator to envelop a vehicle in a bubble of steam — promises to greatly decrease skin friction drag. While a large cavitator enables the occurrence of supercavitation at low velocities, it adds substantial drag at higher speeds. Based on CFD results, we propose a new relationship between drag coefficient and disk cavitator radius, and we predict the optimum cavitator radius for a particular torpedo design.
Efficacy of clindamycin compared with amoxicillin-metronidazole after a 7-day regimen in the treatment of periodontitis in patients with diabetes: a randomized clinical trial
Authors: Gómez-Sandoval Juan Ramón , Robles-Cervantes José Antonio , Hernández-González Sandra Ofelia , Espinel-Bermudez María Claudia , Mariaud-Schmidt Rocío , Martínez-Rodríguez Vianeth , Morgado-Castillo Karina Celia , Mercado-Sesma Arieh Roldán 
Published: January 2020

ObjectiveTo determine the efficacy of clindamycin compared with amoxicillin-metronidazole after a 7-day regimen during nonsurgical treatment of periodontitis in patients with type 2 diabetes mellitus.Research design and methodsIn this double-blind, randomized clinical trial, a total of 42 patients with chronic periodontitis and type 2 diabetes were included. Patients were randomly assigned to treatment with either clindamycin or amoxicillin-metronidazole three times a day during 7 days. Clinical determinations (probing depth, bleeding on probe, and plaque index) were performed to determine the extent and severity of periodontitis before and after the pharmacological treatment.ResultsAfter 7 days of administration of clindamycin or amoxicillin-metronidazole, no differences were observed between the clinical determinations, probing depth (0.44 vs 0.50 mm, p=0.624), plaque index (17.62 vs 15.88%, p=0.910), and bleeding on probing (16.12 vs 22.17%, p=0.163), respectively. There were no adverse events in either group.ConclusionThe administration during 7 days of clindamycin or amoxicillin/metronidazole showed the same efficacy for the reduction of probing depth, plaque index, and bleeding on probing in patients with periodontitis and type 2 diabetes.
Splenic vein thrombosis: rare cause of abdominal pain
Authors: Martín-Jiménez Antonio J , Mera-Gallardo Oliva , García-Gil Daniel 
Published: January 2020

­An 83-year-old woman with a history of hypertension, diabetes and paroxysmal atrial fibrillation anticoagulated with acenocoumarol was brought to the emergency department due to dyspnoea. At admission, the patient reported a 1-week history of malaise, shortness of breath and non-productive cough. She denied fever but reported pain on the left flank. On examination, auscultation showed arrhythmic tones and crackles in the left lower lung field. Laboratory findings showed leucocytosis of 15.32×103/μL, and the C reactive protein was 177 mg/L. The activated partial thromboplastin time was 54.8 s, and the international normalised ratio was 7.09. A chest X-ray showed left lower lobe consolidation with pleural effusion. Point-of-care ultrasound was performed using a low-frequency curved transducer (2–5 MHz). The probe was placed in the left posterior axillary showing a pulmonary consolidation, but also a hypoechoic lesion in the spleen was found (figure 1).Figure 1Ultrasound image of the spleen in longitudinal section demonstrating a large, hypoechoic, wedge-shaped lesion.QuestionWhat is the most likely diagnosis?Splenic abscessSubcapsular splenic haematomaSplenic infarctionSplenic hydatid cystFor answer see page 2