bluuebunny/crossref_metadata_2025_split huggingface dataset:
Characterisation of structure, mechanical and corrosion properties of pure magnesium prepared by powder metallurgy route
Authors: Dvorský Drahomír , Kubásek Jiří , Vojtĕch Dalibor 
Published: September 2021

Abstract
Powder metallurgy is a progressive method for materials production. Final products are usually characterised by improved strength and corrosion properties compared to materials prepared by conventional methods like casting and subsequent thermomechanical processing. The presented work studies the effect of extrusion temperature on the microstructure and properties of products prepared from pure Mg powder. It has been observed that higher extrusion temperature led to the formation of larger grains and massive oxides at interparticle boundaries. Tensile yield strength, compressive, and tensile ultimate strengths were increased at the cost of lower plasticity. The observed mechanical properties were mainly affected by texture, oxides, and grain size. The high corrosion rate was attributed to the presence of a relatively high amount of oxides and impurities which facilitate localized corrosion.
Properties of protective NiCr coatings, deposited by Cold Spray technology
Authors: Houdková Š , Šulcová P , Keslová A. , Lencová K , Duliškovič J 
Published: September 2021

Abstract
The NiCr coatings, deposited by modern Cold Spray technology, and by well-established Twin Wire Arc Spraying and High Velocity Oxygen Fuel technologies, was studied in terms of microstructure, mechanical, tribological and corrosion properties. Compared to other thermal spraying technologies, CS coatings achieve higher cohesive strength and associated tribological properties. The dense structure is responsible for the coatings’ high corrosion protection ability. The influence of CS technological parameters was found negligible, except the usage of nozzle for internal diameter spraying, which results to significant increase of coatings porosity.
Corrosion Resistance of 18Ni-300 maraging steel manufactured by LPBF
Authors: Simson T , Koch J , Zetek M , Zetková I 
Published: September 2021

AbstractThe study describes the corrosion behaviour of LPBF parts made of MAR 300 (EN 1.2709) in sulphuric acid. It includes the influence of the heat treatment on the part’s properties as solution annealed and age hardened with reference to conventional samples. Laser remelted surfaces were examined as well. Due to the layered production of AM components, which is characteristic for this process, high surface roughness occurs. Therefore, for many applications and mostly on functional surfaces, complex post-processing of the surfaces is necessary. The reliable use of the manufactured components, demand knowledge of the specific influence of the selected post-processing methods on the electrochemical behaviour. The corrosion investigation takes place on different sample surfaces, such as milled, turned, sandblasted, untreated, grinded and laser-machined. The results show that there is no correlation between surface treatment and corrosion resistance. However, an increase in corrosion rate due to age hardening of the material can be observed for both LPBF and conventionally produced samples. By laser surface remelting of these age hardened samples, the corrosion resistance of these parts could be increased again, to the same level as in the solution annealed state.
Production and Assembly of Car Body Fifth Door with Use of Dual-Phase Steel HCT500X
Authors: Valeš M , Havelka J , Chrášt’anský L , Tatíček F , Novák V 
Published: September 2021

Abstract
Due to environmental concerns and safety standards in the automotive industry, the development of durable and lightweight cars has become an important topic. Lowering the weight of the car body has become a crucial topic for all manufacturers, regardless of using combustion, electric or hydrogen engines. To fulfil this need a material with a higher strength to weight ratio must be used. Dual-phase steels seem to provide the right combination of mechanical properties for the production of particular car body panels. The goal of this research is to develop robust production of the fifth door part from HCT500X steel (DP500). The goal of this article is also to depict the forming of the selected part and the fifth door assembly for 4th generation of ŠKODA Octavia. Numerical simulation is accomplished within the AutoForm Forming R8 and AutoForm Assembly R9 solutions. Different aspects influencing numerical simulation accuracy and topics relevant to the production chain are discussed in this article. This research is carried out in cooperation with ŠKODA AUTO, a.s.
Ion-plasma modification of surface of ultrafine-grained titanium alloys: effect of substrate on coating properties
Authors: Valiev R R , Modina Iu M , Dyblenko Yu M , Semenova I P 
Published: September 2021

Abstract
This article is focused on research of properties of vacuum-plasma coatings Ti+TiVN and V+TiVN applied to the surface of titanium alloys Ti-6Al-4V and VT8M-1(rus.) (Ti-5.7Al-3.8Mo-1.2Zr-1.3Sn) in ultrafine-grained (UFG) states obtained by two different severe plastic deformation (SPD) techniques-equal-channel angular pressing (ECAP) and rotary swaging (RS). The influence of substrate UFG structure on coatings service properties improvement has been established. It was demonstrated that complex hardening of titanium alloy including formation of bulk UFG structure and applying vacuum-plasma protective coating to the surface significantly increases resistance to erosive wear of the latter in comparison with the substrate having the initial coarse-grained structure.
Numerical study of intake flow field inside the high-speed refrigeration scroll compressor with spiral suction channels in the motor rotor
Authors: Bu G X , Li X R , Li X W , Zhang Y , Wu W F , Wang X L , Zhang X P 
Published: September 2021

Abstract
To control the temperature of the electric motor, the suction gas is introduced flowing through the motor in hermetic scroll compressors. For high-speed compressors, this flow resistance is high, which results in decreasing of the efficiency. In this paper, spiral flow channels were designed inside the motor rotor to decrease the suction flow resistance and increase the refrigerant flow rate inside the scroll compressor. Simulation of the suction flow through the motor was carried out. Two structure of straight and spiral intake channels were brought into the simulation model, under 3000 rpm, 5000 rpm, 7000 rpm and 9000 rpm. The results showed that the spiral channels could increase the refrigerant flow rate inside the motor rotor and the suction pressure of the compressor, and with the increase of the motor speed, the effect of the intake supercharging improved. At 9000 rpm, the suction pressure at the suction port of the compressor increased by about 4% by using spiral channels, while the mass flow rate increased by about 6%. The increases of total refrigerant flow rate in spiral channels are mainly due to the increase in unblocked channels. The size and the layout of the balance weight have a great effect on intake flow.
Simulation and Experiment Study on Dynamic Characteristic of Reed Valve of Reciprocating Compressor Based on Fluid-Structure Interaction Model
Authors: Wang Yanbin , Guo Bei , Ma Kai , Zhou Yuhang 
Published: September 2021

Abstract
The working process of the suction valve with complex shape called “boqi” and the discharge valve with four arms were simulated by the three-dimensional fluid-structure interaction method in this paper. By setting the gap boundary condition between the valve and the valve plate, hanged the connection between the valve and the valve plate in the model, and the problem of flow area connectivity caused by the opening and closing of the valve was solved. It solved the mesh overlapped and distorted problem caused by the valve motion. According to the simulation, the results of valve’s dynamic characteristic and gas pressure were obtained. A valve displacement test bench of reciprocating compressor was built, and the valve motions under different rotational speed and different pressure ratio was tested. Comparing the simulation results with the experimental results, it shows that the three-dimensional fluid-structure interaction model can be used to simulate the interaction between the valve with complex shape and the compressor fluid field. From the simulation results, the pressure cloud map of the valve under different conditions was extracted. Finally, the method proposed in this paper was used to analyze the valve’s displacement, speed and stress.
Modeling the loading factor characteristic of an industrial centrifugal compressor impeller
Authors: Galerkin Yu , Solovyeva O , Soldatova K , Nikiforov A 
Published: September 2021

Abstract
Test data on compressor stages demonstrate that loading factor versus flow coefficient at an impeller exit is of linear character independent of compressibility. Mathematical models of the Universal Modeling Method use this pattern at their core. In the first versions of the Method, two points determined the loading factor characteristic: loading factor at the design point, and at zero flow rate. To calculate these parameters, the user had to define values of two empirical coefficients. The choice of the coefficient is based on experience. An attempt to obtain approximating formulas for these coefficients did not lead to a result with the required accuracy.
In the modern version of the Method, the loading factor characteristic is defined by the angle of its inclination to the ordinate axis and by the loading factor at zero flow rate. The authors have researched test performances of model stages. Simple and definite equations with four geometric parameters were proposed for loading factor characteristics. The calculation error is 1%.
A trailing edge shape influences the loading factor. Blunt and symmetrically tapered blades have the same loading factor. Non-symmetric tapering changes the loading factor by up to plus/minus 4% The results of impeller tests with different blade trailing edges and with vane and vaneless diffusers were generalized. The influence of these factors was taken into account as correcting coefficients in the formulas. The alternative model of loading factor characteristic modeling is included in the Universal Modeling Method and demonstrates good results in design practice.
Theory and practice of neural networks application to building mathematical model of centrifugal compressor vane diffusers
Authors: Nikiforov Aleksandr , Rekovetc Andrei , Galerkin Yuri , Petukhov Evgeniy , Rekstin Aleksey , Semenovsky Vasiliy , Solovyeva Olga 
Published: September 2021

Abstract
Optimal design of centrifugal compressor stages needs special computational and experimental methods, both of them could be costly enough. So new advanced design methods which can provide optimal solution faster are needed. Authors developed the set of mathematical models – Universal modeling method - for describing compressor stages characteristics. Its models are being widened and improved. One the most advanced approaches of model building is based on machine learning. A neural network based method for predicting centrifugal compressor vane diffuser characteristics was developed. Input data for network training was obtained from CFD simulations. The resulting model for diffuser loss coefficient shows good approximation quality and can be used for improvement of VD model in Universal modeling method.
Research and Solution of Vibration Problem of an Air-cooled heat exchanger of Reciprocating Compressor
Authors: Ye Junchao , Yu Xiaoling , Fan Shiyi , Lv Qian , Wang Xiaolin 
Published: September 2021

Abstract
Excessive vibration of complex structures in a multi-excitation environment is an arduous problem. Especially in a reciprocating compressor, how to quickly and accurately position the vibration sources, analyze the excitation features and take effective solutions is of great significance to the safe and stable operation of the compressor. In this paper, the problem of excessive vibration of an air-cooled heat exchanger used in a variable speed CH4 compressor was studied. The air-cooled heat exchanger is composed of tubes, tube boxes and support frame. Its vibration is evoked by complex periodic gas pulsation in the tubes. The vibration model of the heat exchanger was simplifies as a multi-freedom model with periodic excitations using the lumped parameter method. The model has advantages of clear physical concept, easy solution and high accuracy of result. In the model, the air-cooled heat exchanger was simplified as three mass blocks connected by six springs. And then, modal test of the heat exchanger was carried out on site. The vibration modes and natural frequencies of the exchanger were obtained according to the test results. After that, above mentioned multi-freedom model was further simplified as a single freedom vibration model, so that it was convenient to propose the vibration control measures. The practical application results proved that these measures were effective. This research provided a practical and fast analytical method for solutions of compressor vibration problems.
Thermodynamic analysis and optimization of a vapor injection organic Rankine cycle system for low-grade heat recovery
Authors: Li D T , He Z L , Ji L T , Xing Z W 
Published: September 2021

Abstract
The organic Rankine cycle (ORC) system has been widely used in waste heat recovery and geothermal utilization, but the system efficiency is limited due to the large exergy loss in the evaporation process. To improve the performance of ORC systems, in this paper, a vapor injection organic Rankine cycle (VIORC) system using positive-displacement expanders was proposed. The thermodynamic model of the proposed system was developed in views of energy and exergy. The effects of system operation parameters on system performance were investigated, and the system was optimized under different waste heat temperatures. Furthermore, the optimized systems were compared with basic ORC (BORC) systems. Results showed that compared with the BORC system, the proposed system increased the net output power by 3-8% and the exergy efficiency by 0.8-3.2% under the heat source temperature of 90-150 °C. The exergy loss analysis further showed that the reduction of the exergy loss in the evaporation process was the main contribution to the efficiency improvement of the proposed system.
Comparison of the antibacterial effect of a copper-coated surface on Staphylococcus epidermidis and Pseudomonas putida in different physiological states
Authors: Vibornijs V , Liepins J , Selga T , Bankovskis V , Cosemans P , Muter O 
Published: September 2021

Abstract
The antimicrobial effect of Cu is dependent on several factors, including the physiological state of test-cultures. The present study aimed to compare the antibacterial effect of the newly developed Cu-coated surface, using bacterial cultures of Staphylococcus epidermidis and Pseudomonas putida harvested at exponential (6h) and stationary (24h) phases of growth as well as from a colony. Growth kinetics and cell morphology were characterised for each culture. The colony forming units log reduction values for a Cu-coated surface for cultures at exponential, stationary phase, and from a colony were 1.08, 2.85, and 2.14, respectively, for S. epidermidis, while 1.57, 3.95, and 3.14, respectively, for P. putida. The Cu-coated surface reduced the signal of ATP bioluminescence in both S. epidermidis and P. putida, with the more pronounced inhibition being for the cells at exponential and stationary phase of growth. The data indicated that bacterial cultures at the early exponential stage of growth are more resistant towards antimicrobial surfaces than cells at the stationary phase of growth and from a colony. This fact is of great importance for estimating the efficiency of antimicrobial coatings.
Efficiency of Community Face Coverings and Surgical Masks to Limit the Spread of Aerosol
Authors: Chazelet Sandrine , Pacault Stephanie 
Published: September 2021

Abstract
In the current pandemic context of COVID-19, people wear different types of masks, particularly in their workplace, to limit the spread of the virus. Depending on their activity and work environment, employees are required to wear community face coverings, cloth masks with a transparent windows, surgical masks, reusable masks, or respirators. The objective of this study was to evaluate the efficiency as source control of these masks, i.e., when worn to protect the environment from the spread of particles emitted by the wearer. An experimental test bench including a dummy head and a breathing simulator associated with a DEHS droplet generator emitting 1 or 3 µm particles in the exhaled stream is used. Source control efficiency is calculated from the total flux of particles emitted in the test section without and with a mask. Seventeen models of masks are tested. Three breathing rate conditions were studied: from rest to heavy breathing, with average rates of 13, 27, and 45 L/min. Source control efficiencies vary from one mask to another. Among community face coverings (seven models) the values ranged from 15.6 to 33.8% for a medium intensity breath. The efficiencies of surgical masks (three models) ranged from 17.4 to 28.3% for the same breathing cycle. The community face coverings and the disposable surgical masks present equivalent values of source control efficiency, respectively, 25.9 and 24.1% at 1 µm and 31.5 and 23.2% at 3 µm. The respirators show higher source control efficiency than the other types of masks (76.7% at 1 µm and 82.5% at 3 µm). The statistical analysis of the data shows no effect of the breathing flow rate and an interaction effect between mask type and particle size. No differences in source control were found for the two particle sizes or the different experimental breathing rates for the respirators and the surgical masks. But the community face coverings and the cloth masks with transparent window present a source control efficiency which increases with the particle size. Varying levels of efficiency were measured with higher source control for respirators than for other types of masks. In the context of a respiratory protection programme, they can provide an effective barrier to the spread of the virus. But these results show also that no mask can stop all the particles emitted by its wearer. Regardless of the type of mask, other barrier measures (ventilation, social distancing, and hygiene) are then necessary.
ShinyArchR.UiO: user-friendly,integrative and open-source tool for visualization of single-cell ATAC-seq data using ArchR
Authors: Sharma Ankush , Akshay Akshay , Rogne Marie , Eskeland Ragnhild 
Published: September 2021

ABSTRACT

Motivation
Mapping of chromatin accessibility landscapes in single-cells and the integration with gene expression enables a better understanding of gene regulatory mechanisms defining cell identities and cell-fate determination in development and disease. Generally, raw data generated from single-cell Assay for Transposase-Accessible Chromatin sequencing (scATAC-seq) are deposited in repositories that are generally inaccessible due to lack of in-depth knowledge of computational programming.

Results
We have developed ShinyArchR.UiO, an R-based shiny app, that facilitates scATAC-seq data accessibility and visualization in a user-friendly, interactive and open-source web interface. ShinyArchR.UiO is an application that can streamline collaborative efforts for interpretation of massive chromatin accessibility datasets and allow for open access data sharing for wider audiences.

Availability and implementation
https://Github.com/EskelandLab/ShinyArchRUiO and a demo server with a hematopoietic tutorial dataset https://cancell.medisin.uio.no/ShinyArchR.UiO

Supplementary information
Supplementary data are available at Bioinformatics online.
Dynamic connectivity predicts acute motor impairment and recovery post-stroke
Authors: Bonkhoff Anna K , Rehme Anne K , Hensel Lukas , Tscherpel Caroline , Volz Lukas J , Espinoza Flor A , Gazula Harshvardhan , Vergara Victor M , Fink Gereon R , Calhoun Vince D , Rost Natalia S , Grefkes Christian 
Published: September 2021

AbstractThorough assessment of cerebral dysfunction after acute lesions is paramount to optimize predicting clinical outcomes. We here built random forest classifier-based prediction models of acute motor impairment and recovery post-stroke. Predictions relied on structural and resting-state fMRI data from 54 stroke patients scanned within the first days of symptom onset. Functional connectivity was estimated via static and dynamic approaches. Motor performance was phenotyped in the acute phase and 6 months later. A model based on the time spent in specific dynamic connectivity configurations achieved the best discrimination between patients with and without motor impairments (out-of-sample area under the curve, 95% confidence interval: 0.67 ± 0.01). In contrast, patients with moderate-to-severe impairments could be differentiated from patients with mild deficits using a model based on the variability of dynamic connectivity (0.83 ± 0.01). Here, the variability of the connectivity between ipsilesional sensorimotor cortex and putamen discriminated the most between patients. Finally, motor recovery was best predicted by the time spent in specific connectivity configurations (0.89 ± 0.01) in combination with the initial impairment. Here, better recovery was linked to a shorter time spent in a functionally integrated configuration. Dynamic connectivity-derived parameters constitute potent predictors of acute impairment and recovery, which, in the future, might inform personalized therapy regimens to promote stroke recovery.
Neoadjuvant chemoradiotherapy followed by resection for esophageal cancer: clinical outcomes with the ‘CROSS-regimen’ in daily practice
Authors: Cloos-v.Balen Marissa , Portier Edmée S H , Fiocco Marta , Hartgrink Henk H , Langers Alexandra M J , Neelis Karen J , Lips Irene M , Peters Femke P , Slingerland Marije 
Published: September 2021

Summary

Background and objectives
Since the first results of the Dutch randomized CROSS-trial, neoadjuvant chemoradiotherapy (CRT) using carboplatin and paclitaxel followed by resection for primary resectable nonmetastatic esophageal cancer (EC) has been implemented as standard curative treatment in the Netherlands. The purpose of this retrospective study is to evaluate the clinical outcomes of this treatment in daily practice in a large academic hospital.

Methods
Medical records of patients treated for primary resectable nonmetastatic EC between May 2010 and December 2015 at our institution were reviewed. Treatment consisted of five weekly courses of carboplatin (area under the curve 2) and paclitaxel (50 mg/m2) with concurrent external beam radiotherapy (23 fractions of 1.8 Gy), followed by transthoracic or transhiatal resection. Data on survival, progression, acute and late toxicity were recorded.

Results
A total of 145 patients were included. Median follow-up was 43 months. Median overall survival (OS) and progression-free survival (PFS) were 35 (95% confidence interval [CI] 29.8–40.2) and 30 (95% CI 19.7–40.3) months, respectively, with corresponding 3-year OS and PFS of 49.6% (95% CI 40.4–58.8) and 45.6% (95% CI 36.6–54.6). Acute toxicity grade ≥3 was observed in 25.5% of patients. Late adverse events grade ≥3 were seen in 24.8%, mostly esophageal stenosis.

Conclusion
Neoadjuvant CRT followed by resection for primary resectable nonmetastatic EC in daily practice results in a 3-year OS of 49.6% (95% CI 40.4–58.8) and PFS of 45.6% (95% CI 36.6–54.6), compared with 58% (51–65%) and 51% (43–58%) within the CROSS-trial. The slightly poorer survival in our daily practice group might be due to the presence of less favorable patient and tumor characteristics in daily practice, as is to be expected in daily practice. Toxicity was comparable with that in the CROSS-trial and considered acceptable.