Parallel Running Research Articles

Oxide Formation during Transpassive Material Removal of Martensitic 42CrMo4 Steel by Electrochemical Machining.

The efficiency of material removal by electrochemical machining (ECM) and rim zone modifications is highly dependent on material composition, the chemical surface condition at the break through potential, the electrolyte, the machining parameters and the resulting current densities and local current density distribution at the surfaces. The ECM process is mechanistically determined by transpassive anodic metal dissolution and layer formation at high voltages and specific electrolytic compositions. The mechanisms of transpassive anodic metal dissolution and oxide formation are not fully understood yet for steels such as 42CrMo4. Therefore, martensitic 42CrMo4 was subjected to ECM in sodium nitrate solution with two different current densities and compared to the native oxide of ground 42CrMo4. The material removal rate as well as anodic dissolution and transpassive oxide formation were investigated by mass spectroscopic analysis (ICP-MS) and (angle-resolved) X-ray photoelectron spectroscopy ((AR)XPS) after ECM. The results revealed the formation of a Fe3−xO4 mixed oxide and a change of the oxidation state for iron, chromium and molybdenum, e.g., 25% Fe (II) was present in the oxide at 20.6 A/cm2 and was substituted by Fe (III) at 34.0 A/cm2 to an amount of 10% Fe (II). Furthermore, ECM processing of 42CrMo4 in sodium nitrate solution was strongly determined by a stationary process with two parallel running steps: 1. Transpassive Fe3−xO4 mixed oxide formation/repassivation; as well as 2. dissolution of the transpassive oxide at the metal surface.

Experimental investigation of sliding wear behaviour of boron carbide and mica reinforced aluminium alloy hybrid metal matrix composites using Box-Behnken design

Abstract In this work, wear performance of hybrid aluminium metal matrix composite (AMMC) was studied owing to the influence of mica addition on dry sliding. Technique of Stir casting is used to prepare the hybrid composite with AA6061 as matrix phase, 10% boron carbide (B4C) as primary reinforcement and varying weight fractions of mica (3%, 4% and 5%). Box-Behnken design of Response surface methodology (RSM) is used to analyze the experiments. Pin-on-Disc (PoD) equipment is used to carry out the work for varying sliding speeds, axial load and mica percentage, at room temperature. Coefficient of Friction (CoF) and Friction Force (FF) was evaluated and optimized using desirability approach of RSM. For CoF, the most significant parameter is rotational speed, and for FF it is axial load. Scanning Electron Microscope (SEM) images of worn surface shows grove formation and roughness running in parallel with the sliding direction and abrasive wear mechanism is observed. Optimum condition arrived are; 3% reinforcement of mica, 695 rpm of rotational speed, 0.5 kgf of axial load and 3 min of sliding time with a CoF of 0.207 and FF of 5.47 N.

ОСОБЕННОСТИ ПРИМЕНЕНИЯ МЕТОДА ПОСЛЕДОВАТЕЛЬНОГО УТЯЖЕЛЕНИЯ ПРИ АНАЛИЗЕ СТАТИЧЕСКОЙ УСТОЙЧИВОСТИ ИСТОЧНИКОВ РАСПРЕДЕЛЕННОЙ ГЕНЕРАЦИИ

Design and operation of distributed generation facilities needs to provide for sufficient margin of static sta-bility in a variety of operating situations, including normal and post-emergency operation in parallel with the outer grid (the power system). Power system protections are often placed where the on-site power plants connect to the power system; these protections enable the loaded generators to become islanded in case of emergency; rated margin of static stability must be available in such post-emergency operation. To analyze static stability of synchronous generators and motor loads, we propose combining gradual equalization and gradual tran-sition to post-emergency parameters. However, the latter method has different quirks when applied to static stabi-lity testing of generators, depending on whether they are running in parallel or islanded. Besides, application of this method requires multiple constraints pertaining to the functioning of on-site power plants, among other things. The authors hereof have developed a single algorithm for static stability testing of generators and loads that applies well to on-site power plants whether they are islanded on running in parallel to the grid. The algorithm adjusts for constraints on excitation systems and is implemented in KATRAN software. A computational experiment is described herein that concerns an electricity delivery system that is powered by distributed generation facilities and carries heterogeneous motor loads. Specific features of such studies are additionally described.

GPU Tensor Cores for Fast Arithmetic Reductions

This article proposes a parallel algorithm for computing the arithmetic reduction of n numbers as a set of matrix-multiply accumulate (MMA) operations that are executed simultaneously by GPU tensor cores. The analysis, assuming tensors of size m x m, shows that the proposed algorithm has a parallel running time of T(n) = 5log <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">m2</sub> n and a speedup of S = 45log <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2m</sub> 2 over a canonical parallel reduction. Experimental performance results on a Tesla V100 GPU show that the tensor-core based approach is energy efficient and runs up to ~ 3:2× and 2× faster than a standard GPU-based reduction and Nvidia's CUB library, respectively, while keeping the numerical error below 1 percent with respect to a double precision CPU reduction. The chained design of the algorithm allows a flexible configuration of GPU thread-blocks and the optimal values found through experimentation agree with the theoretical ones. The results obtained in this work show that GPU tensor cores are relevant not only for Deep Learning or Linear Algebra computations, but also for applications that require the acceleration of large summations.

Parallel Efficient Mesh Deformation Method Based On Support Vector Regression

Mesh deformation method is widely used in unsteady numerical simulations involving moving boundaries. This kind of method redistributes the position of grid points in accordance with the movement of the computational domain without changing their connectivity relations. In this paper, we present a parallel mesh deformation method based on the support vector machine regression (SVR). In each time step, the proposed method first trains three SVRs by the coordinates of the boundary points and their known displacements in each direction, and then predicts the displacements of the internal points using the SVRs. After deforming the mesh, the dual-time step flow solver is used to solve the governing equations. To ensure the consistency of the method running in parallel, the training part of the method is executed with all global boundary points in each decomposed domain. Therefore, each CPU needs to maintain a copy of the entire boundary points via a point-to-point communication. The internal evaluation of the method is predicted separately in each decomposed domain without any data dependency. An oscillatory and transient pitching airfoil case is simulated to demonstrate the applicability of the proposed mesh deformation method, and its parallel efficiency is over 60% with 64 cores.

Synthesis and Crystal Structure of the Short LnSb2O4Br Series (Ln = Eu–Tb) and Luminescence Properties of Eu3+-Doped Samples

Pale yellow crystals of LnSb2O4Br (Ln = Eu–Tb) were synthesized via high temperature solid-state reactions from antimony sesquioxide, the respective lanthanoid sesquioxides and tribromides. Single-crystal X-ray diffraction studies revealed a layered structure in the monoclinic space group P21/c. In contrast to hitherto reported quaternary lanthanoid(III) halide oxoantimonates(III), in LnSb2O4Br the lanthanoid(III) cations are exclusively coordinated by oxygen atoms in the form of square hemiprisms. These [LnO8]13− polyhedra form layers parallel to (100) by sharing common edges. All antimony(III) cations are coordinated by three oxygen atoms forming ψ1-tetrahedral [SbO3]3− units, which have oxygen atoms in common building up meandering strands along [001] according to {[SbO2/2vO1/1t]–}∞1 (v = vertex-sharing, t = terminal). The bromide anions are located between two layers of these parallel running oxoantimonate(III) strands and have no bonding contacts with the Ln3+ cations. Since Sb3+ is known to be an efficient sensitizer for Ln3+ emission, photoluminescence studies were carried out to characterize the optical properties and assess their suitability as light phosphors. Indeed, for both, GdSb2O4Br and TbSb2O4Br doped with about 1.0–1.5 at-% Eu3+ efficient sensitization of the Eu3+ emission could be detected. For TbSb2O4Br, in addition, a remarkably high energy transfer from Tb3+ to Eu3+ could be detected that leads to a substantially increased Eu3+ emission intensity, rendering it an efficient red light emitting material.

Simultaneous Events, Parallel Themes, Spatial Oppositions: A Comparative Content Analysis of Traditional Dance

This paper focuses on the smallest units and micro-structures of traditional dance. I propose a new approach that ventures beyond the identification of simple syntagmatic relations derived from the temporal succession of movements: a former practice of dance analyses that relied on theories borrowed from linguistics and music. The following discussion, based on the analysis of movement content as spatial change, demonstrates the existence of independent but simultaneous movement events in dance: each event possesses an expressive potential and the capacity for performance as a single rhythmical unit. Identifying events creates the possibility of separating parallel running, autonomous movement themes. Amongst the examined structures, an exceptional one, here termed contrakinesis, emerges, which represents spatial opposition as a recurring, characteristic phenomenon in East Central European traditional dance. The theory of simultaneous events and parallel themes reveals that concepts of expression in traditional dance can be comprehensively recognized only through a content-oriented exploration relying on movement analysis: an approach derived from investigating the dance itself.

Technical Realization of Integrating Bone Age Artificial Intelligence Assessment System with Hospital RIS-PACS Network

To explore the integration method and technical realization of artificial intelligence bone age assessment system with the hospital RIS-PACS network and workflow. Two sets of artificial intelligence based on bone age assessment systems (CHBoneAI 1.0/2.0) were developed. The intelligent system was further integrated with RIS-PACS based on the http protocol in Python flask web framework. The two sets of systems were successfully integrated into the local network and RIS-PACS in hospital. The deployment has been smoothly running for nearly 3 years. Within the current network setting, it takes less than 3 s to complete bone age assessment for a single patient. The artificial intelligence based bone age assessment system has been deployed in clinical RIS-PACS platform and the "running in parallel", which is marking a success of Stage-I and paving the way to Stage-II where the intelligent systems can evolve to become more powerful in particular of the system self-evolution and the "running alternatively".

A two-equation local-correlation-based laminar-turbulent transition modeling scheme for external aerodynamics

A local-correlation-based laminar-turbulent transition model has been developed for external aerodynamic problems and coupled with the Spalart-Allmaras (S−A) turbulence model. This laminar-turbulent transition modeling scheme is then termed as the γ−SA model. It has been validated against a series of two- and three-dimensional test cases with a relatively wide range of Reynolds numbers and free-stream turbulence intensity levels. Results show that the γ−SA model can give accurate transition-onset-location predictions, as well as more accurate predictions on the force coefficients than the underlying S−A turbulence model at various angles of attack. Comparison with the classic SST−γ−Reθ transition model shows that the γ−SA model can achieve comparable results, with the expect of less time or memory consumption, as the γ−SA model has two equations fewer than the former one. With a newly proposed local-farfield mixed turbulence intensity strategy, the turbulence intensity on the inlet or farfield boundary can be conveniently set directly with the value tested for the wind tunnel or the value as expected, while achieving local turbulence intensity variation. Moreover, the γ−SA model employs only local variables, which makes it totally modern-CFD-compatible and very appropriate for large-scale parallel running using unstructured grids. In the future, it can be modified into a robust and efficient DES-type model with the consideration of transition process.

Geochemical characterisation of the alkaline and hyperalkaline groundwater in the Othrys Ophiolite Massif, central Greece

The complex geology of Greece includes two important parallel running ophiolitic belts. The Othrys Massif in central Greece belongs to the westernmost of them. In the current study, 33 water samples from cold hyperalkaline and hypothermal (T < 40°C) alkaline springs and 30 gas samples (either dissolved or free) were collected at 17 different sites in and around this wide ophiolite outcrop, aiming to determine the origin of fluids and evidence gas-water-rock interaction processes taking place in the area. Water samples were analysed for their chemical (major ions and trace elements) and isotope (δ18O-H2O, δ2H-H2O) composition. They can be subdivided into alkaline (pH 11 and Ca-OH composition). Trace elements generally showed very low concentrations and mostly inversely correlated with pH. Gases were analysed for their chemical (He, Ne, Ar, H2, O2, N2, CH4, C2H6, CO2 and H2S) and isotope (δ13C-CH4, δ2H-CH4, δ13C-CO2) composition. Samples from alkaline waters were mainly dominated by CH4 (from 128,000 to 915,000 μmol/mol), while hyperalkaline waters showed a N2-rich composition (from 727,000 to 977,000 μmol/mol). Methane had a wide range of isotope compositions (δ13C-CH4 from -74.5 to -14.5 ‰ and δ2H-CH4 from -343 to -62 ‰). Alkaline waters present the most negative isotope values for CH4, evidencing a biogenic (both thermogenic and microbial) origin. Many of the hyperalkaline waters had CH4 isotope values compatible with an abiogenic origin through serpentinization processes but occasionaly very negative values were recorded, indicating sometimes a clear biogenic contribution. Finally, few samples both from alkaline and hyperalkaline waters showed some evidence of secondary oxidation processes.

An Improved Relative GNSS Tracking Method Utilizing Single Frequency Receivers.

The Global Navigation Satellite Systems (GNSS) becomes the primary choice for device localization in outdoor situations. At the same time, many applications do not require precise absolute Earth coordinates, but instead, inferring the geometric configuration information of the constituent nodes in the system by relative positioning. The Real-Time Kinematic (RTK) technique shows its efficiency and accuracy in calculating the relative position. However, when the cycle slips occur, the RTK method may take a long time to obtain a fixed ambiguity value, and the positioning result will be a “float” solution with a low meter accuracy. The novel method presented in this paper is based on the Relative GNSS Tracking Algorithm (Regtrack). It calculates the changes in the relative baseline between two receivers without an ambiguity estimation. The dead reckoning method is used to give out the relative baseline solution while a parallel running Extended Kalman Filter (EKF) method reinitiates the relative baseline when too many validation failures happen. We conducted both static and kinematic tests to assess the performance of the new methodology. The experimental results show that the proposed strategy can give accurate millimeter-scale solutions of relative motion vectors in adjacent two epochs. The relative baseline solution can be sub-decimeter level with or without the base station is holding static. In the meantime, when the initial tracking point and base station coordinates are precisely obtained, the tracking result error can be only 40 cm away from the ground truth after a 25 min drive test in an urban environment. The efficiency test shows that the proposed method can be a real-time method, the time that calculates one epoch of measurement data is no more than 80 ms and is less than 10 ms for best results. The novel method can be used as a more robust and accurate ambiguity free tracking approach for outdoor applications.

A Stochastic MPC Based Energy Management System for Simultaneous Participation in Continuous and Discrete Prosumer-to-Prosumer Energy Markets

This article studies the exchange of self-produced renewable energy between prosumers (and with pure end consumers), through the discrete trading of energy packages and proposes a framework for optimizing this exchange. In order to mitigate the imbalances derived from discrepancies between production and consumption and their respective forecasts, the simultaneous continuous trading of instantaneous power quotas is proposed, giving rise to a time-ahead market running in parallel with a real-time one. An energy management system (EMS) based on stochastic model predictive control (SMPC) simultaneously determines the optimal bidding strategies for both markets, as well as the optimal utilisation of any energy storage system (ESS). Simulations carried out for a heterogeneous group of agents show that those with SMPC-EMS achieve savings of between 3% and 15% in their energy operation economic result. The proposed structures allows the peer-to-peer (P2P) energy trading between end users without ESS and constitute a viable alternative to avoid deviation penalties in secondary regulation markets.

A configurable multiplex data transfer model for asynchronous and heterogeneous FPGA accelerators on single DMA device

To reduce DMA utilization for multiple algorithm IPs on FPGA, a channel configurable and multiplex DMA device (CMDMA) is proposed for asynchronous and heterogeneous algorithm IPs. Firstly, we abstract the entities and data-flow in CMDMA system with a formal description for function definition and work-flow analysis. Then based on the functions and work-flow, we design and implement a prototype of CMDMA, which includes CMDMA software driver (SW) and hardware circuits (HW) of one DMA IP, a configurable input switch (CISwitch), algorithm IPs, and an asynchronous output switch (AOSwitch). The configurable function of CMDMA is implemented by CISwitch through a configuration port in HW-level, and a configurable Round-Robin (CRR) algorithm is proposed to implement channel and input data schedule in SW-level. For output, a channel distinguishable output buffer (ChnDistBuf) is proposed, which is able to deliver channel ID and data size to SW earlier than the end time of an algorithm IP. With a double interrupt coordination method of both ChnDistBuf and algorithm IPs, CMDMA is able to successively store complete output data from different algorithm IPs. With a double interrupt coordination method of both ChnDistBuf and algorithm IPs, CMDMA is able to successively store complete output data from different algorithm IPs. The experiments based on 4 heterogeneous matrix multiplication algorithm IPs on Xilinx Zynq platform show that CMDMA is able to improve about 8%-29% average algorithm acceleration rates on single algorithm IP compared to the exclusive method that one DMA works for one algorithm IP only, and it is able to increase about 10–40 MB/s and 5–15 MB/s of DMA input and output data throughput with multiple algorithm IPs running in parallel. Moreover, the extended LUT and FF resources in CMDMA are 756 and 1219, both of which are about 1% of Zynq platform. Besides, in a double CNN algorithm IPs test on Mnist application, an enhanced function of data broadcasting in CMDMA is able to improve 4 s than the system with 4 exclusive DMA running in parallel, meanwhile reduce 3 DMA utilization and 0.03 W power consumption.

Monitoring Parallel Robotic Cultivations with Online Multivariate Analysis

In conditional microbial screening, a limited number of candidate strains are tested at different conditions searching for the optimal operation strategy in production (e.g., temperature and pH shifts, media composition as well as feeding and induction strategies). To achieve this, cultivation volumes of &gt;10 mL and advanced control schemes are required to allow appropriate sampling and analyses. Operations become even more complex when the analytical methods are integrated into the robot facility. Among other multivariate data analysis methods, principal component analysis (PCA) techniques have especially gained popularity in high throughput screening. However, an important issue specific to high throughput bioprocess development is the lack of so-called golden batches that could be used as a basis for multivariate analysis. In this study, we establish and present a program to monitor dynamic parallel cultivations in a high throughput facility. PCA was used for process monitoring and automated fault detection of 24 parallel running experiments using recombinant E. coli cells expressing three different fluorescence proteins as the model organism. This approach allowed for capturing events like stirrer failures and blockage of the aeration system and provided a good signal to noise ratio. The developed application can be easily integrated in existing data- and device-infrastructures, allowing automated and remote monitoring of parallel bioreactor systems.

Reduction of Uncertainties for Safety Assessment of Automated Driving Under Parallel Simulations

Many achievements concerning developments in the field of automated driving have been made. However, automated driving still faces the challenge of safety validation. Conventional methods are not suitable any more for this highly complex automation system. Therefore, the method named Virtual Assessment of Automation in Field Operation (VAAFO) is motivated. In this approach, automated driving system has no access to actuators but rather runs parallel to the human driver. Consequently, this approach is divided into two modules: online trajectory comparison and offline safety assessment. This paper focuses on the second module, in which uncertainties in world model are reduced and then the safety of Automated Vehicle (AV) is evaluated. Retrospective post-processing combined with Joint Integrated Probabilistic Data Association (JIPDA) tracker is put forward to reduce existence uncertainties. State uncertainties are reduced by an Unscented Rauch-Tung-Striebel smoother (URTSS). Furthermore, inverse TTC and remaining lateral distance are utilized to assess the safety of AV in the corrected world model. The results demonstrate that retrospective post-processing combined with JIPDA can reduce existence uncertainties greatly. URTSS is very useful for reducing state uncertainties. The studied case illustrates that the safety of AV can be assessed by parallel running and critical scenarios are found accordingly.

Phenomenon of Transformer Sympathetic Inrush and Analysis of an Example

According to a mal-operation accident of differential protection which is caused by the effect of a switching-on transformer with no load on a parallel running transformer in a 35KV substation, the emergency and the development of transformer sympathetic inrush current was analysed from the aspect of the flux. And the three-phase differential current and their second harmonic component were obtained, which shows that the mal-operation wasn’t caused by the low second harmonic component in the differential current but by the changed transfer characteristics of the current transformer, which leads to an increase in the differential current.

Morphological remodeling of the intramural coronary resistance artery network geometry in chronically Angiotensin II infused hypertensive female rats

Segmental remodeling of resistance arteries, inhibition of angiogenetic processes, their rarefaction by AngiotensinII and hypertension are accepted facts. Less is known about alterations in resistance artery network geometry potentially induced by them. Female rats were infused with 100 ng/kg/min AngiotensinII with osmotic minipumps for four weeks that raised mean arterial blood pressure from 98 ± 3 to 125 ± 7 mmHg. Geometry of the left coronary artery system was studied on plastic casts and on in situ microsurgically prepared, saline infused video-microscoped networks (n = 13 and 11 controls and hypertensives, respectively). Parallel running branches, broken course of larger branches, multiple branchings and branch crossings have been identified (13 and 74 such deformities, in control and hypertensive networks, respectively, p < 0.01). Bifurcation angles increased with increasing asymmetry of daughter branches but not in hypertensives. Dividing the whole network (theoretically) into several hundreds of 50μm long ring units, ring frequency peaked at 200μm diameter in normal networks. This peak diminished and was replaced by a peak at 300μm in hypertensives (p < 0.01). In controls, diameter of vascular units decreased at a fairly even rate with flow distance from the orifice. The 350, 200, 150μm diameter units were found with highest frequencies at flow distances around 2.5, 5.5 and 7.5mm, respectively. This regular pattern disintegrated in hypertensives. Higher blood flow routes were needed to cover the same distance from the orifice (p < 0.01). Shrinkage and diminishment of many parallel connected 200μm segments, concomitant enlargement of many larger segments accompanied with morphological deformities can be expected to contribute to elevated vascular resistance.

Depth optimization of quantum search algorithms beyond Grover's algorithm

Grover's quantum search algorithm provides a quadratic speedup over the classical one. The computational complexity is based on the number of queries to the oracle. However, depth is a more modern metric for noisy intermediate-scale quantum computers. We propose a new depth optimization method for quantum search algorithms. We show that Grover's algorithm is not optimal in depth. We propose a quantum search algorithm, which can be divided into several stages. Each stage has a new initialization, which is a rescaling of the database. This decreases errors. The multistage design is natural for parallel running of the quantum search algorithm.

Fine Tuning of Rank Based VM Placement and Scheduling Strategies on Opennebula Based Cloud

The HPC Clouds are good option over deploying actual physical infrastructure. This helps in running applications efficiently and in cost effective manner as applications leverage resources in pay as you go manner. But HPC clouds suffer performance issues due to Hypervisor layer. This work addresses the issue by coming up with a VM placement strategy considering the intensity of the applications and also resources available in the host machines and avoid performance degradation of parallel running applications. This placement strategy identifies the and ranks the available host machines and places the maximum possible VMs in highest ranking nodes. This avoids communication over the network since the VMs use shared memory for communication.

Prediction of Reversible Lithium Plating with a Pseudo-3D Lithium-Ion Battery Model

Fast charging of lithium-ion batteries remains one of the most delicate challenges for the automotive industry, being seriously affected by the formation of lithium metal in the negative electrode. Here we present a physicochemical pseudo-3D model that explicitly includes the plating reaction as side reaction running in parallel to the main intercalation reaction. The thermodynamics of the plating reaction are modeled depending on temperature and ion concentration, which differs from the often-used assumption of a constant plating condition of 0 V anode potential. The reaction kinetics are described with an Arrhenius-type rate law parameterized from an extensive literature research. Re-intercalation of plated lithium was modeled to take place either via reverse plating (solution-mediated) or via an explicit interfacial reaction (surface-mediated). At low temperatures not only the main processes (intercalation and solid-state diffusion) become slow, but also the plating reaction itself becomes slower. Using this model, we are able to predict typical macroscopic experimental observables that are indicative of plating, that is, a voltage plateau during discharge and a voltage drop upon temperature increase. A spatiotemporal analysis of the internal cell states allows a quantitative insight into the competition between intercalation and plating. Finally, we calculate operation maps over a wide range of C-rates and temperatures that allow to assess plating propensity as function of operating condition.