bluuebunny/crossref_metadata_2025 huggingface dataset:
HfX2 (X = Cl, Br, I) Monolayer and Type II Heterostructures with Promising Photovoltaic Characteristics*
Authors: Huang Xingyong , Zhou Liujiang , Yan Luo , Wang You , Zhang Wei , Xie Xiumin , Xu Qiang , Song Hai-Zhi
Published: December 2020

Two-dimensional (2D) materials and their corresponding van der Waals (vdW) heterostructures are considered as promising candidates for highly efficient solar cell applications. A series of 2D HfX2 (X = Cl, Br, I) monolayers are proposed, via first-principle calculations. The vibrational phonon spectra and molecular dynamics simulation results indicate that HfX2 monolayers possess dynamical and thermodynamical stability. Moreover, their electronic structure shows that their Heyd–Scuseria–Ernzerhof(HSE06)-based band values (1.033–1.475 eV) are suitable as donor systems for excitonic solar cells (XSCs). The material’s significant visible-light absorbing capability (∼105 cm−1) and superior power conversion efficiency (∼20%) are demonstrated by establishing a reasonable type II vdW heterostructure. This suggests the significant potential of HfX2 monolayers as a candidate material for XSCs.
Inversion/Mirror Symmetry-Protected Dirac Cones in Distorted Ruby Lattices
Authors: Sun Lei , Zhang Xiaoming , Gao Han , Liu Jian , Liu Feng , Zhao Mingwen
Published: December 2020

The exotic electronic band structures of Ruby and Star lattices, characterized by Dirac cone and nontrivial topology, offer a unique platform for the study of two-dimensional (2D) Dirac materials. In general, an ideal isotropic Dirac cone is protected by time reversal symmetry and inversion, so that its robustness against lattice distortion is not only of fundamental interest but also crucial to practical applications. Here we systematically investigate the robustness of Dirac cone in a Ruby lattice against four typical lattice distortions that break the inversion and/or mirror symmetry in the transition from Ruby to Star. Using a tight-binding approach, we show that the isotropic Dirac cones and their related topological features remain intact in the rotationally distorted lattices that preserve the inversion symmetry (i-Ruby lattice) or the in-plane mirror symmetry (m-Ruby lattice). On the other hand, the Dirac cones are gapped in the a- and b-Ruby lattices that break both these lattice symmetries or inversion. Furthermore, a rotational unitary matrix is identified to transform the original into the distorted lattice. The symmetry-protected Dirac cones were also verified in photonic crystal systems. The robust Dirac cones revealed in the non-mirror symmetric i-Ruby and non-centrosymmetric m-Ruby lattices provide a general guidance for the design of 2D Dirac materials.
Optomechanically induced optical responses with non-rotating wave approximation
Authors: Yan Xiao-Bo
Published: December 2020

Slow light propagation is an important phenomenon in quantum optics. Here, we theoretically study the properties of slow light in a simple optomechanical system considering an effect of non-rotating wave approximation (NRWA) that was ignored in previous related works. With the NRWA effect, the ultraslow light can be easily achieved at the window of optomechanically induced transparency, especially in unresolved sideband regime. From the theoretical results, we find the upper bound of the time delay is exactly the mechanical ringdown time which can last for several minutes (mHz linewidth) in recent experiments. Additionally, the interesting phenomena of the perfect optomechanically induced transmission and absorption are studied in the system with the NRWA effect. We believe the results can be used to control optical transmission in modern optical networks.
Numerical simulations of hydrogen interstitial diffusion and ferroelectricity degradation in lead titanate films
Authors: You Jeong Ho , Zhu Lin , Gray Cooper , Wang Zhi , Yeo Chang-Dong
Published: December 2020

Numerical simulations have been performed to study hydrogen interstitial diffusion and ferroelectric degradation in lead titanate films. The computational method consists of two parts: hydrogen diffusion property calculations using density functional theory (DFT) and ferroelectric property calculations using molecular dynamics (MD) simulations. The hydrogen interstitial diffusion path and the activation energy have been obtained using DFT calculations. With the obtained diffusion properties, the distributions of hydrogen impurities have been calculated using Fick’s second law and used as input to MD simulations, with various diffusion times and hydrogen surface concentrations. It has been found that magnitudes of remnant polarization and coercive electric fields decrease with increasing the diffusion time and the hydrogen surface concentration. The distribution of hydrogen impurities is another critical factor to ferroelectric responses. Compared to a uniform distribution of hydrogen impurities, the nonuniform distribution diminishes the ferroelectric properties more severely. A heavily defective region due to the nonuniform hydrogen distribution reduces the effective film thickness and induces the in-plane ferroelectric domain formations.
Experimental and numerical studies on kV scattered x-ray imaging for real-time image guidance in radiation therapy
Authors: Huang Yanqi , Yang Kai , Lai Youfang , Liu Huan , Shen Chenyang , Zhong Yuncheng , Shao Yiping , Li Xinhua , Liu Bob , Jia Xun
Published: December 2020

Motion management is a critical component of image guided radiotherapy for lung cancer. We previously proposed a scheme using kV scattered x-ray photons for marker-less real-time image guidance in lung cancer radiotherapy. This study reports our recent progress using the photon counting detection technique to demonstrate potential feasibility of this method and using Monte Carlo (MC) simulations and ray-tracing calculations to characterize the performance. In our scheme, a thin slice of x-ray beam was directed to the target and we measured the outgoing scattered photons using a photon counting detector with a parallel-hole collimator to establish the correspondence between detector pixels and scatter positions. Image corrections of geometry, beam attenuation and scattering angle were performed to convert the raw image to the actual image of Compton attenuation coefficient. We set up a MC simulation system using an in-house developed GPU-based MC package modeling the image formation process. We also performed ray-tracing calculations to investigate the impacts of imaging system geometry on resulting image resolution. The experiment demonstrated feasibility of using a photon counting detector to measure scattered x-ray photons and generate the proposed scattered x-ray image. After correction, x-ray scattering image intensity and Compton scattering attenuation coefficient were linearly related, with R
2 greater than 0.9. Contrast to noise ratios of different objects were improved and the values in experimental results and MC simulation results agreed with each other. Ray-tracing calculations revealed the dependence of image resolution on imaging geometry. The image resolution increases with reduced source to object distance and increased collimator height. The study demonstrated potential feasibility of using scattered x-ray imaging as a real-time image guidance method in radiation therapy.
A hierarchical model of abdominal configuration changes extracted from golden angle radial magnetic resonance imaging
Authors: Zhang Yuhang , Kashani Rojano , Cao Yue , Lawrence Theodore S , Johansson Adam , Balter James M
Published: December 2020

Abdominal organs are subject to a variety of physiological forces that superimpose their effects to influence local motion and configuration. These forces not only include breathing, but can also arise from cyclic antral contractions and a range of slow configuration changes. To elucidate each individual motion pattern as well as their combined effects, a hierarchical motion model was built for characterization of these 3 motion modes (characterized as deformation maps between states) using golden angle radial MR signals. Breathing motions are characterized first. Antral contraction states are then reconstructed after breathing motion-induced deformation are corrected; slow configuration change states are further extracted from breathing motion-corrected image reconstructions. The hierarchical model is established based on these multimodal states, which can be either individually shown or combined to demonstrate any arbitrary composited motion patterns. The model was evaluated using 20 MR scans acquired from 9 subjects. Poor reproducibility of breathing motions both within as well as between scan sessions was observed, with an average intra-subject difference of 1.6 cycles min−1 for average breathing frequencies of 12.0 cycles min−1. Antral contraction frequency distributions were more stable than breathing, but also presented poor reproducibility between scans with an average difference of 0.3 cycles min−1 for average frequencies of 3.2 cycles min−1. The magnitudes of motions beyond breathing were found to be significant, with 14.4 and 33.8 mm maximal motions measured from antral contraction and slow configuration changes, respectively. Hierarchical motion models have potential in multiple applications in radiotherapy, including improving the accuracy of dose delivery estimation, providing guidance for margin creation, and supporting advanced decisions and strategies for immobilization, treatment monitoring and gating.
Near-threshold production of antihydrogen positive ion in positronium–antihydrogen collision
Authors: Yamashita Takuma , Kino Yasushi , Hiyama Emiko , Jonsell Svante , Froelich Piotr
Published: December 2020

Near-threshold production of antihydrogen ion (

H

̄

+

) in positronium–antihydrogen collisions is predicted by a rigorous four-body scattering calculation. The convergence of the cross sections for the rearrangement and for all competing reactions (elastic scattering, de/excitation and de/polarization of positronium) is carefully examined against partial waves. The multi-channel scattering solutions are composed of functions that diagonalize the four-body Hamiltonian, and scattering functions that satisfy the correct asymptotic boundary conditions. The production rates of

H

̄

+

show large discrepancies compared to more approximate calculations.
Understanding the conceptual frameworks and methods of the food–energy–water nexus at the household level for development-oriented policy support: a systematic review
Authors: Itayi Chirenje Leonard , Mohan Geetha , Saito Osamu
Published: December 2020

This paper undertakes a systematic review of the literature to understand current trends in the food–energy–water (FEW) nexus for development-oriented policy support. The paper follows three steps: (a) a bibliometric analysis of FEW nexus research, (b) a content analysis of FEW nexus research, and (c) development of a framework that fills existing gaps in FEW nexus research. The review found that FEW nexus approaches have gained ground in academia as a resource management tool and policy guide; however, the process does not have a robust conceptualization. The current FEW nexus approaches focus on national, regional, and international scales of analysis to understand the three sectors’ interactions. Further, these approaches underline the nexus processes, which have been researched in detail, including synergies and tradeoffs. However, research on the FEW nexus has not adequately explored the social factors that form part of the nexus, especially at the local household scale. Factors such as the gender dynamics of resource ownership, work roles at different scales, household incomes, and culture are essential components that are yet to be explored in FEW nexus research. Most of the existing frameworks on the FEW nexus overemphasize models and the quantitative measurement of processes while paying limited attention to social aspects. Still, these social aspects are crucial, especially on the household scale; therefore, to overcome these gaps, this paper proposes a FEW nexus framework at the local household scale that includes socio-economic determinants.
Ecological and forestry features of broad leaved forest and their role in the conservation of biodiversity in the Novgorod region
Authors: Smirnov I A , Nikonov M V
Published: December 2020

The article provides information on the distribution and condition of broad leaved forest in the Novgorod region. A semi-landscape distribution of broad leaved forest sections is presented. Based on the data of 143 sample plots, the biological diversity of broad leaved forest was estimated.
Patch shape and size effect on performance of in-situ scarf patch repair in aircraft panel
Authors: Dwivedi Kishan , Pathak Himanshu
Published: December 2020

Patch repairing technique is effective and efficient approach to enhance structural performance of aged aircraft panels. The presented work emphases on studying the patch shape and size effect on scarf composite patch repair of aluminium aircraft panel under thermal, thermo-elastic and mechanical load. In this work, patched repaired structural member has been simulated by ABAQUS software to find out the performance of patch repair in term of patch thickness and patch shape. Five different patch shapes are chosen to analysis: circular, square, hexagonal, rectangular and trapezoidal with different patch thickness 1, 2, 3, 4, 5 mm. The Heat transfer and coupled temp-displacement analysis has been performed under cure temperature 394 K for in-situ patch repair model. The analysis of the critical von-Mises stress and heat flux load distribution in composite patch repair system allows us to estimate performance in composite patch repair system. The results show that patch shape and size has significant effect on magnitude of heat flux load and induced von-Mises stress. Trapezoidal shape of composite patch repair has lower value of von-Mises stress and heat flux load as compared to all four shapes of composite patches.
Modeling and Simulation of a Semi-active Vehicle Suspension system using PID Controller
Authors: Narwade Prashant , Deshmukh Ravindra , Nagarkar Mahesh , Bankar Milind
Published: December 2020

In this article, the numerical simulation of Magneto-rheological (MR) damper has been done using PID controller in Matlab-Simulink software to compare between the regular Macpherson strut and semi active suspension systems. The Magneto-rheological damper is a control device filled with Magneto-rheological fluid which changes damping force by changing property of viscosity on application of magnetic field. The results show that proportional integral derivative (PID) controller used to control damper in semi-active suspension is more efficient to reduce road disturbances than the regular suspension using Macpherson strut. Vehicle chassis displacement and acceleration can be reduced within milliseconds of time.
Role of thickness variation on the tailored bistability of unsymmetric composite laminates
Authors: Anilkumar P M , Phanendra Kumar A , Haldar A , Rao B N
Published: December 2020

Unsymmetric composite laminates exhibit two stable configurations at room temperature after being cured at elevated temperature. Bistability of cross-ply laminates is due to the presence of residual strains imparted during the curing process. A simple snap-through process can be used to switch from one stable shape to another. The amount of snap-through force required for attaining the other stable shape depends on the total strain energy of the laminate in the first cured shape. Bistable shapes of the conventional square laminates are in the same energy level, which means the stable configurations are equally stable and results in equal snap-through and snap-back forces. By tailoring the energy levels of stable shapes, snap-through and snap-back forces can be varied. From various studies in the past, it is observed that bistable laminates have enormous potential for morphing applications. In some of the practical applications, one may require stable shapes at different energy levels, with unequal snap-through and snap-back energies for the shape transition. This study aims to tailor the energy levels of bistable shapes of the square laminate by varying the thickness of individual layers in the considered [0/90] square laminates. A detailed parametric study is performed in commercially available finite element software. It is concluded from the study that individual lamina thickness has a noticeable influence on the bistability of cross-ply laminates.
CFD Investigation of Impact of Vessel configuration and Different Impeller Types in Stirred Tank
Authors: Pathak Mohit , Tamphasna Devi Thiyam
Published: December 2020

Computational Fluid Dynamics (CFD) study is carried out to simulate the flow characteristics of different impeller types in stirred tanks of baffled and un-baffled system. The hydrodynamic behavior induced by a Rushton turbine (RT6) and Curve Blade impeller (CD-6) is numerically analysed by solving the Navier-Stokes equations coupling with k-ε turbulence model with Multi-reference frame (MRF) impeller model. The predicted results were validated with available experimental published data and show a satisfactory agreement. The power characteristics for the two agitator systems (baffled and un-baffled) were obtained for the turbulent system of the fluid flow. In these conditions, it is found that the power number depended strongly on the length of the baffle when baffled is provided. Therefore, the presence of the baffles in the tank greatly improved the mixing performance of the system but consumes higher power than the un-baffled system. Similarly, mixing improves when Rushton impeller is employed but consumes higher power than the Curve Blade impeller. Hence, it was observed that overall efficiency of the system is better when baffled system of Curve Blade impeller is opted in any mixing operation.
Geometric optimization of planar membrane reflector used in gossamer space structure
Authors: Shinde S. D. , Soni M. , Upadhyay S. H. , Sakhare S. , Singh K. S.
Published: December 2020

In recent trends membrane reflector has increased its applications in space missions due its significant advantage such as light in weight, higher folding and packaging efficiency, ease of deployment, low on-Board volume requirement. Geometry of the membrane reflector has significant influence on its the stress distribution and area of deformation, subsequently determining the stiffness and geometrical parameters of its supporting structures. The present study uses a Taguchi optimization method of orthogonal array for investigating the membrane geometry parameter and its effect on membrane reflector.
Effect of Impactor velocity and boundary condition on low velocity impact finite element modelling of CFRP composite laminates
Authors: Kaware K. R. , Kotambkar M. S.
Published: December 2020

The demand for Composite structures is increasing in different engineering fields such as automobile, aircraft, civil because of its higher specific mechanical properties. It’s very important to consider failure modes like fiber breakage, delamination, matrix cracking, etc. when it is impacted by a foreign object such as dropping of tool (impact type events). Susceptibility of damage due to low velocity impact is more in the laminated composite structures than metal. It is important to study the response of composite for varying velocities with different boundary conditions in case of low velocity impact analysis. Thus, this paper presents the combined effect of different boundary conditions with varying velocities of impactor on low velocity impact modelling of CFRP composite laminates. Numerical analysis is performed on T700GC/M21 material with layup [02/452/902/-452]s to study the force-time/displacement curve. Numerical analysis is performed using ABAQUS 6.14. First, Numerical analysis is carried out for impactor velocities varying from 2.5 m/s to 10 m/s. In ABAQUS/Explicit, two boundary conditions i.e. simply supported edges boundary condition SSSS and Clamped supported edges, CCCC are used to study the force-time/displacement curve. Out of that numerical results of impactor velocity 5 m/s with boundary condition SSSS is validated with results of literature by studying force-time/displacement curves. The numerical findings revealed that; as impactor velocity increases, the force and displacement also increases. Also, current simulation results are closely matching with the existing numerical and experimental data.
Health Monitoring of Induced Draft Fan in an Aluminium Smelter
Authors: Das S S , Mohanty J K , Panda D , Sarkar Pratima , Pradhan P K
Published: December 2020

Maintenance is highly essential as to support the machine availability, product quality and plant safety. The timely repair at minimum coast is the basic criteria for good maintenance. Appropriate maintenance can sustain continuous and reliable operation with reduction in down time, high productivity, number of secondary failures, low inventory level and accident of the plant. In spite of high initial investment, most of the industries adopt condition based maintenance (CBM) to avoid sudden disruption in production. CBM is an important tool which includes observing, monitoring, diagnosis and prognosis for running a plant seamlessly, as this maintenance planning and actions have become an integral part of engineering investigation. In this paper, condition monitoring of Induced Draft (ID) fan in an Aluminium smelter has been done while it was in operation. The vibration of ID fan was measured and analyzed to detect the defect of its impeller and corrected subsequently.
Design, analysis and optimization of 12 cylinder v-type diesel engine components
Authors: Aman Kumar , Chandanpat Ankit , Kiran Pawar , Angadi Shivashankar , Totla Nilesh
Published: December 2020

The designing, material selection and stress analysis are important processes in mechanical engineering design. The below brief study deals with the afore-mentioned processes conducted on the piston, connecting rod and crankshaft of a 12 cylinder V-type engine used for wood cutting application. The objective of this study was to optimize the weight of the given parts and increase their capacities to withstand different loads by means of iterative design changes as well as material selection for the three components. Pre-existing engine data and empirical relationships were used to generate a mathematical model for the design procedure and Ashby standards were followed for material selection for the above-mentioned parts. The Computer Aided Design (CAD) modelling and analysis of these parts was conducted in the Solidworks software.
Linear and non-linear optical properties of reactive magnetron DC sputtered ZnTe thin films for opto-electronic devices
Authors: Hymavathi B , Kumar B Rajesh , Rao T Subba
Published: December 2020

Zinc Telluride thin films were prepared by reactive magnetron direct current sputtering method and the temperature of the glass substrates changed from 150 to 350 °C. The band gap of ZnTe films increased from 2.32 to 2.42eV. The normal dispersion of refractive index (n) for ZnTe films is described using the model of Wemple-Di Domenico (WDD) single-oscillator. The oscillator energy, dispersive energy and static refractive index (no) of ZnTe films were reported. The Verdet coefficient (V) is estimated from the normal dispersion studies. The first-order (Ist) and third-order (IIIrd) non-linear optical susceptibilities (χ(1), χ(3)), refractive index (n2) of ZnTe films were calculated.
Prediction of Lateral-Vibration Responses of A Full Size Cantilever Beam by Using Those of Its Scale Models
Authors: Kumar S. Naresh , Sairam S. , Jena Shakti P
Published: December 2020

The main objective of this article is to study and calculate lateral vibration responses of the cantilever beam by using a scale model and the associated scaling laws. Lateral vibration responses of a cantilever beam are analyzed theoretically and to validate results using a method of finite element to calibrate vibration response of a similar beam. We get the results and then we had compared both scale model and full-size cantilever beam model. Initially derive the solution of free response and steady-state response for the full and scaled model. Later, the scaling-laws for all the applicable parameters concerning the cantilever beam in the size of full and its scale beam of free vibration are get from the Euler’s equation of motion of the last two systems. Next, by dimensional analysis find the scaling factors for applicable dimensions and properties of required two systems. And in Finite element method introduce property matrices and equations of motion of cantilever beam system and also systematic procedure to get element property matrices of the beam is shown. In the end it is solved by Method of Eigen value problem with the help of Mat lab software. Lastly the impact of specimen dimensions on the similarity basis, natural frequencies of cantilever beam specimen is investigated.
Experimental Investigations of Canola Oil Lubrication with Nano-Crystalline MoS2 Additives in CNC End Milling of Aluminium Alloy
Authors: Mandru Suresh Kumar , Raju P. Ramamurthy , Ratnam CH.
Published: December 2020

Since the past few decades, manufacturing operations including the milling of metals use various types of coolants and lubricants. These are composed of chemicals and other pollutant factors, which are very dangerous and hazardous to the nature and human. And also the increasing demands of high productivity for the machining requirements leaves no choice but to use high cutting velocity along with higher feed rates. These renewed machining conditions leads to the generation of high cutting temperatures, which reduces tool life with poor product quality. Hence there is a need to find the alternative coolants and lubricants, which reduces the above factors in addition to machining cost. In general lubrication is attributed for the solving of heat generation related issues at the cutting zone. Due to some inherent properties like cooling, lubrication and functions like flushing of chips, the cutting fluids leads to better performances during milling operations. As the conventional way of using fluids are less efficient during high production machining, it is observed that nano fluids have better properties in terms of transfer of heat from the cutting zone. Economic aspects are considered during the use of nano fluids by applying the phenomenon of Minimum quantity lubrication (MQL). The work is an attempt in the direction of using nano fluids as alternative lubricants in milling operations by the study of tool temperature and quality of surface finish.
Effect of Geocell on the behaviour of Soil
Authors: Lal Dharmesh , Prasanna K. Laxmi , Rao K. Rohith , Kamalekkar Prithhe , Bajrang J.
Published: December 2020

As the use of plastic has rapidly increased in past few years, attempts are made to use it as reinforcement material to escalate the soil properties. For the present study, plastic bottles are cut and made into geocell to use it as the reinforcement to the soil. Use of plastic as reinforcement has great advantages, as it is low cost and easily available. Results of plate load tests on soil and plastic bottle reinforced soil are presented and compared. Finally, it is observed that plastic bottle reinforced soil provides improved performance when compared to that of unreinforced one. An improvement of 1.86 times the plain sand is attained when plastic bottle reinforcement was used.
A Study on Properties of Recycled Coarse Aggregate and It’s Concrete
Authors: Harish B A , Ramana N Venkata , Gnaneswar K
Published: December 2020

This paper presents recycled coarse aggregate and its concrete properties. Recycled coarse aggregate exhibits lower values for loose and dry-rodded unit weight and high water absorption values than the natural coarse aggregate. Natural aggregate concrete exhibits higher mechanical strength than recycled coarse aggregate concrete. Results pronounced that the percentage increment of recycled aggregate content is inversely proportional to the strength and concluded that optimum dose of recycled aggregate is 50% and proposed a model to estimate compressive, split tensile and flexural strengths of recycled coarse aggregate concrete. The maximum replacement of RCA in concrete is 50%, and the proposed models show excellent compatibility with experimental results.
CFD Simulation and Analytical Validation of Rectangular and Square microchannel heat sink with liquid water as cooling medium
Authors: Pawar Saurabh Narayan , Totla Nilesh Balkishanji
Published: December 2020

In present work, both analytical and CFD investigation was performed to check the microchannel heat sink cooling performance, made up of copper with two different microchannel cross sections with shape of rectangle and square. CFD analysis is conducted with water as working fluid for both of the cross sections and Reynolds number ranging from 600 to 1000. A copper microchannel heat sink with bottom size of 25.4mm×25.4mm and height of 2.384mm is selected and CFD analysis was carried out and at bottom constant heat flux boundary condition is assumed. For comparison between two cross sections, the hydraulic diameter used is same for both. Rectangular cross section microchannel showed better cooling performance as compared to square cross section microchannel. Both analytical and CFD simulation results of pressure drop in rectangular microchannel heat sink are in good agreement with a difference of 18.9%.
Acoustic emission examination of high strength steel M250 pressure vessels for aerospace applications
Authors: Wuriti Gowri Shankar , Chattopadhyaya Somnath , Tessy Thomas
Published: December 2020

This paper deals at experiences with the Acoustic Emission (AE) monitoring of critical pressure vessels during qualification proof pressure test. Conventional Non Destructive Evaluation (NDE) methods have limitations in evaluating the vessel. There is a high probability that they may not provide information required to evaluate the quality of vessel. In contrary, Acoustic emission technique has a high probability of detecting the likely defects in pressure vessels prior to the failure. This technique has to be applied under pressure load. These pressure loads create stresses in the vessel. During increasing pressure loads AE signals are obtained from discontinuities and other locations of stress concentrations. AE is very useful in estimating the soundness of critical pressure vessels used by aerospace industry that is made up of high strength Maraging steels. AE Testing and result analysis was carried out according to standard procedures. During the tests, AE signals were recorded and post analysis was done to understand the response from the material. The experimentation revealed that the amplitude of AE signals were less than the corresponding AE signals for critical crack opening, during pressurization cycle. Also, at proof pressure, a 2 minutes hold time was observed with no increase in amplitude of signals. AE activity can detect any defect growth during proof pressure test. Inspection was carried-out in accordance with a set of acceptance criteria based on available literature and specimen level tests.
Effect of cathode end plate on passive direct methanol fuel cell performance
Authors: Deepak K
Published: December 2020

Direct methanol fuel cell (DMFC) belongs to the class of fuel cells that use polymer electrolyte membrane and operate on methanol-water mixture. The low overall performance of passive DMFC compared to active DMFC is due to the slow anode reaction combined with inefficient cathode reaction. In this work, an attempt was made to augment the passive DMFC performance by modifying the structural design of the cathode end plate (CEP). The passive DMFC was fabricated and the performance was investigated experimentally. Three different CEP duct configurations were studied using 1 to 5 M methanol mass fraction. The results indicated higher performance for square duct CEP configuration, with 5 M methanol mixture.
Mechanical Characterization and Machining of MgAZ91D/SiC/Al2O3MMC by Squeeze Cast Method
Authors: Prudhvi Raj K , Seshappa A , Anjaneya Prasad B
Published: December 2020

In the automotive industry, the high surface finish and superior mechanical property materials are prepared with the help of the squeeze casting process. The paper investigates on the chosen materials of MMC cast using magnesium alloy (Mg-AZ91D) reinforced with various %wt of silicon carbide (SiC) also aluminum oxide (Al2O3) of nano particulates (20 nm). The preferred squeeze casting technique produces magnesium matrix composites along with silicon carbide (SiC) and aluminum oxide (Al2O3) particulates direct to an absolute drenched of inside the liquefy magnesium of hybrid metal matrix composite. Using CNC lathe and orthogonal array (L9), Magnesium metal matrix composites (Mg-AZ91D) are machined. To determine Metal Removal Rate (MRR) and Surface roughness (Ra) with various input parameters having the CNC lathe. Magnesium metal matrix composites (Mg-MMC) also, comparing the results with the unreinforced magnesium alloy with reinforcement of silicon carbide (SiC) and aluminum oxide (Al2O3) of nano particulates, Mechanical properties of the Magnesium metal matrix composite (Mg-MMC) and optimal machining parameters are evaluated.
Dynamic Behavior of Ropeway String
Authors: Jena Shakti P , Ibrahim Mohd , Subbaratnam B. , Naresh Kumar S
Published: December 2020

In this paper a new approach for dynamic behavior of a string is aimed to study lateral vibrations induced in an elastic ropeway string. We are going to deal with the dynamic behavior of a string. In hilly areas we have problem for traveling from one place to another place. There we are using a rope drive system using a string as a rope. A ropeway is a type of maritime lifting gadget used to move light stores and hardware across waterways. Here, multiple ropeways are designed by using solid works and then analyzing with static, transient and dynamic boundary conditions. To suggest optimum materials for optimum ropeway string, 4 materials were chosen (SAE 1020, SAE1137, Al-l7075, Al- 7475) to analyze and study the dynamic behavior of ropeway string by knowing each material results, comparing with each other material results and then showing suitable tables and graphs, finally concluding thesis with optimum material with optimum ropeway string to improve the performance and their durability.
Metastability in performance measurements of perovskite PV devices: a systematic approach
*
Authors: Bardizza Giorgio , Müllejans Harald , Pavanello Diego , Dunlop Ewan D
Published: December 2020

Performance measurements of photovoltaic devices, including metastable ones, should reflect as closely as possible the behaviour of these devices when deployed in the field, i.e. at constant illumination and fixed conditions. We review the wide-ranging behaviour observed in and previously proposed measurement solutions for perovskite solar cells (PSC) devices and further illustrate the variability during measurement with recent examples from our own experience. We propose a generic measurement protocol for PSC devices to ensure that electrical characterisation under simulated sunlight reflects real life conditions. The approach focusses on determining the steady-state maximum-power output under continuous illumination rather than relying on the I–V characteristics. Given the large variations in device behaviour, this protocol is particularly suitable in cases where a priori information about the devices under test is not available. We conclude that the approach to the electrical characterisation of PSC devices should shift from traditional I–V curves to the maximum-power output under steady-state conditions. The latter is the simplest and most reliable method to evaluate, assess and compare PSC technologies when power and efficiency reporting are required. This protocol also contributes to harmonising comparison between different calibration laboratories thus contributing to increased confidence in the results.
Regularity of geodesics in the spaces of convex and plurisubharmonic functions
Authors: Abja Soufian , Dinew Sławomir
Published: December 2020

In this note we investigate the regularity of geodesics in the space of convex and plurisubharmonic functions. In the real setting we prove (optimal) local

C

1
,
1

C^{1,1}

regularity. We construct examples which prove that the global

C

1
,
1

C^{1,1}

regularity fails both in the real and complex case in contrast to the Kähler manifold setting. Finally we show a necessary and sufficient conditions for existence of a smooth geodesic between two smooth strictly convex functions.
Weight gain associated with insulin detemir vs insulin glargine in clinical practice: A retrospective longitudinal cohort study
Authors: Wadsworth Thomas G , Carr Glenda G , Madaras-Kelly Karl , Remington Richard , Bell Justin
Published: December 2020

Purpose

In comparative randomized studies, use of insulin detemir has been consistently demonstrated to be associated with less weight gain than the industry standard, insulin glargine. However, the magnitude of the relative reduction in weight gain with use of insulin determir vs insulin glargine in regulatory studies (reported values ranged from 0.77 kg to 3.6 kg) may not be generalizable to patients in real-world practice conditions. A study was conducted to substantiate detemir’s purported weight-sparing advantage over insulin glargine in newly treated patients with type 2 diabetes mellitus under the conditions found in a clinical practice setting.

Methods

A retrospective longitudinal cohort study design was applied in reviewing electronic medical records to identify insulin-naive, overweight patients with type 2 diabetes who received insulin detemir or insulin glargine therapy continued for up to 1 year. Patient weights at baseline and at each subsequent clinic visit after treatment initiation were identified. The primary outcome was the maximum weight increase from baseline after exposure to insulin detemir or glargine. The difference-in-differences (DiD) mean total body weight change was tested by analysis of covariance (ANCOVA).

Results

One hundred nine patient records (56 of patients who received insulin glargine and 53 of patients who received insulin detemir) met study criteria and underwent full abstraction. The covariate-adjusted estimated mean change in body weight associated with use of insulin detemir vs insulin glargine was –1.5 kg (95% CI, –2.89 to –0.12 kg; P = 0.04).

Conclusion

The mean weight gain associated with detemir use was significantly less than the mean weight change observed with glargine use. The magnitude of weight change was consistent with that demonstrated in randomized controlled trials. These results further substantiate detemir’s purported comparative weight-sparing properties under conditions found in a real-world practice setting.
Exposure and Management of the Health Risk for the Use of Formaldehyde and Xylene in a Large Pathology Laboratory
Authors: Fustinoni Silvia , Campo Laura , Spinazzè Andrea , Cribiù Fulvia Milena , Chiappa Laura , Sapino Anna , Mercadante Rosa , Olgiati Luca , Boniardi Luca , Cavallo Domenico Maria , Riboldi Luciano , Ferrero Stefano , Boggio Francesca
Published: December 2020

Background

Formaldehyde and xylene are two hazardous chemicals widely used in pathology laboratories all over the world. The aim of this work was to survey a large volume pathology lab, measuring exposure of workers and residents to formaldehyde and xylene, and verify the efficacy of the undertaken preventive actions and the accomplishment with occupational limit values.

Methods

Environmental, personal, and biological monitoring of exposure to formaldehyde and xylene in different lab rooms and in 29 lab attendants was repeated yearly from 2017 to 2020. Continuous monitoring of airborne formaldehyde was performed to evaluate the pattern of airborne concentrations while specific tasks were performed. Several risk management and mitigation measures, including setting a new grossing room, reducing the number of samples to be soaked in formaldehyde, and improving the lab practices and equipment, such as the use of chemical hoods, were undertaken after each monitoring campaign, based on the results obtained from the exposure monitoring.

Results

Significant exposures to formaldehyde in pathologists and residents, especially during the grossing of samples, were observed in the first 2 years, with exposure exceeding the occupational exposure limit value; the following surveys showed that the risk management and mitigation measures were effective in reducing airborne concentrations and personal exposure. Xylene, assessed with both environmental and biological monitoring, was always well below the occupational exposure limit value and biological limit values, respectively.

Conclusion

Critical exposure to air formaldehyde in attendants of a pathology laboratory could be reduced with the re-organization of lab spaces, new and improved work procedures, and awareness and training initiatives.
Effect of Long-Term Diving Exposure on Sleep of Male Occupational Divers in Southern Taiwan: A Cross-Sectional Study
Authors: Tseng Wei-Shih , Tzeng Nian-Sheng , Lin Kung-Hung , Huang Nan-Chieh , Huang Man-Yuan , Kang Bor-Hwang
Published: December 2020

Objective

Divers with a history of decompression sickness may be at high risk for sleep problems. However, limited studies have investigated the relationship between diving exposure and sleep problems of occupational divers. This study investigated the association between diving exposure and sleep quality and quantity among male occupational divers in southern Taiwan.

Methods

This descriptive, cross-sectional study included 52 occupational divers and 121 non-divers recruited from southern Taiwan in 2018. Survey data were collected using the Taiwanese version of the Hospital Anxiety and Depression Scale, Pittsburgh Sleep Quality Index, Epworth Sleepiness Scale, and a self-report questionnaire that included demographic variables, diving exposure/protocols, and factors associated with sleep quality.

Results

Among all participants examined, occupational divers were significantly more likely to have both poor sleep quality (adjusted odds ratio [OR] = 3.00; 95% confidence interval [CI] = 1.48–6.06; P = 0.002) and excessive daytime sleepiness (adjusted OR = 4.49; 95% CI = 2.12–9.52; P < 0.001). The diving exposure time, depth, ascent rate, and decompression table use showed no significant associations between poor and good sleepers in the divers group. However, a history of decompression sickness was associated with poor sleep quality among divers (adjusted OR = 2.20; 95% CI = 1.07–4.54; P = 0.032).

Conclusions

Our results showed that occupational divers had poor sleep quality and more excessive sleepiness than non-divers. Decompression sickness likely contributes to poor sleep quality. Prevention and early detection of decompression sickness-related sleep problems should be an occupational health priority.
ProteomeExpert: a Docker image-based web server for exploring, modeling, visualizing and mining quantitative proteomic datasets
Authors: Zhu Tiansheng , Chen Hao , Yan Xishan , Wu Zhicheng , Zhou Xiaoxu , Xiao Qi , Ge Weigang , Zhang Qiushi , Xu Chao , Xu Luang , Ruan Guan , Xue Zhangzhi , Yuan Chunhui , Chen Guo-Bo , Guo Tiannan
Published: December 2020

The rapid progresses of high-throughput sequencing technology-based omics and mass spectrometry-based proteomics, such as data-independent acquisition and its penetration to clinical studies have generated increasing number of proteomic datasets containing hundreds to thousands of samples. To analyze these quantitative proteomic datasets and other omics (e.g. transcriptomics and metabolomics) datasets more efficiently and conveniently, we present a web server-based software tool ProteomeExpert implemented in Docker, which offers various analysis tools for experimental design, data mining, interpretation and visualization of quantitative proteomic datasets. ProteomeExpert can be deployed on an operating system with Docker installed or with R language environment.

Availability and implementation

The Docker image of ProteomeExpert is freely available from https://hub.docker.com/r/lifeinfo/proteomeexpert. The source code of ProteomeExpert is also openly accessible at http://www.github.com/guomics-lab/ProteomeExpert/. In addition, a demo server is provided at https://proteomic.shinyapps.io/peserver/.

Supplementary information

Supplementary data are available at Bioinformatics online.
EM-stellar: benchmarking deep learning for electron microscopy image segmentation
Authors: Khadangi Afshin , Boudier Thomas , Rajagopal Vijay
Published: December 2020

Motivation

The inherent low contrast of electron microscopy (EM) datasets presents a significant challenge for rapid segmentation of cellular ultrastructures from EM data. This challenge is particularly prominent when working with high-resolution big-datasets that are now acquired using electron tomography and serial block-face imaging techniques. Deep learning (DL) methods offer an exciting opportunity to automate the segmentation process by learning from manual annotations of a small sample of EM data. While many DL methods are being rapidly adopted to segment EM data no benchmark analysis has been conducted on these methods to date.

Results

We present EM-stellar, a platform that is hosted on Google Colab that can be used to benchmark the performance of a range of state-of-the-art DL methods on user-provided datasets. Using EM-stellar we show that the performance of any DL method is dependent on the properties of the images being segmented. It also follows that no single DL method performs consistently across all performance evaluation metrics.

Availability and implementation

EM-stellar (code and data) is written in Python and is freely available under MIT license on GitHub (https://github.com/cellsmb/em-stellar).

Supplementary information

Supplementary data are available at Bioinformatics online.
Multiple spontaneous coronary artery dissections associated with intravenous daunorubicin treatment for acute myelocytic leukaemia: a case report
Authors: Chien Do Van , Hai Pham Dang , Nhung Le Thi , Son Pham Truong
Published: December 2020

Background

Multiple spontaneous coronary artery dissection (SCAD) is a rare condition which may lead to serious consequences such as sudden cardiac death, acute myocardial infarction (AMI), and acute heart failure.

Case summary

In this paper, we report the case of a 57-year-old woman with acute myelocytic leukaemia who was undergoing her second phase of chemotherapy. After the first induction cycle of intravenous infusion of daunorubicin, the patient experienced chest pain, shortness of breath, and low blood pressure. The electrocardiograms revealed significant ST-elevation in the D1, aVL, and V2–V6 leads, which indicated AMI. Coronary catheterization showed spontaneous coronary dissection in the mid-left descending coronary artery and first obtuse marginal artery of the circumflex. The patient died immediately.

Discussion

This is the first reported case of multiple SCAD associated with intravenous (IV) daunorubicin infusion. We also reviewed the literature and proposed the mechanism of this complication.