bluuebunny/crossref_metadata_2025_split huggingface dataset:
Analysis of piston applications due to fuel burning
Authors: Stan L C , Faităr C 
Published: September 2020

Abstract
The paper aims to analyze the demands of four-stroke naval pistons. To begin with, a brief analysis of the evolution of shipbuilding was made. Mechanical requests are produced by the gas pressure force and inertial force of the alternate moving masses. Under its action, the piston suffers an axial deformation. The thermal demands appearing in the engine are all the more important as the engine power is higher. The possibility of calculating them is more difficult due to the complexity of the thermogazodinamic phenomena in the engine cylinder. Thus, in the piston head, which comes in contact with both the hot gases and the fresh (much cooler) load, a non-stationary heat flow is installed which leads to a certain thermal regime of the engine. Considering the demands outlined in the last chapter, they lead to the conclusion that although the most unfavourable loading situation was considered as the maximum pressure during the processes and even exaggerated in establishing the working conditions, the piston is still close to the elastic limit. This demonstrates that the way of calculating the dimensions of the piston is correct and safe, as long as its constructive dimensions are not oversized.
Physical and mechanical characterization of resonance spruce (Picea Abies L)
Authors: Stanciu M D , Dinulică F , Cîrstea I C 
Published: September 2020

Abstract
The aim of the paper is to presents the experimental results related to physical and mechanical characteristics of resonance wood, one of the most qualitative wood material. Resonance wood, mainly spruce (Picea abies L) is used for musical instruments manufacturing and Romania is well known for resonance wood located in Gurghiu Mountains. Physical features of resonance spruce in terms of colour, ring width, ring regularity, latewood proportion and density were determined on samples provided by musical instruments factory from Reghin. The density profile of resonance spruce samples was determined using the X-Ray Density Profile Analyzer DPX300 and color of samples was obtained by means of chroma meter CR-400 Konica Minolta. Mechanical properties as elasticity modulus, viscous modulus, damping were obtained using dynamic mechanical analysis (DMA).
Influence of thermo-mechanical deformations on the positioning accuracy of CNC machine tools
Authors: Stoica A , Stan Gh 
Published: September 2020

Abstract
This research aims at improving the machining accuracy of the CNC machine tools by decreasing the errors caused by the thermo-mechanical deformations and increasing the positioning accuracy of the mobile element. This work analyses and researches the effects of the thermo-mechanical deformation on the positioning accuracy of the feed kinematical linkages of the CNC machine tools that are using the indirect measuring system of the position. The analysis is focused on feed kinematical linkages having rapid speed rates, of 40 m/min, that use a preloaded bearing system of the ball screw, supported at both ends. Constructive methods are also presented for decreasing the temperature at the heat generating sources by thermo-stating both the ball screw and its bearings. Through thermostats the temperature in the ball screw and its bearings is decreased, that leads to decreasing its influence on the positioning accuracy. The thermo-stating of the ball screw makes possible to keep a constant preloading force of the two ball screw nuts and, as far as the bearings are concerned, the coolant agent is the same as the lubrication agent that leads to a smooth running and, by default, to expanding the life of the feed kinematical linkage.
Method for estimating price procurement of standardized components. Case study – springs
Authors: Tiriplică P G , Rosu M M , Dijmărescu M R , Tarbă I C 
Published: September 2020

Abstract
This paper presents a mode for applying a methodology of estimating the price, presented in previous researches and applied for the price forecasting of springs for light / heavy load. By applying this methodology, the manufacturing companies will succeed in forecasting the procurement price from price offers given to the customers, offers related to similar quotation requests, for products with constructive characteristics comparable or different to the most currently proposed ones. The methodology proposed can be used for the procurement price forecasting for standard components from different equipment from manufacturing process systems. This methodology has as starting point a causal forecast model that is based on the hypothesis that the variable we want to forecast (the product procurement price) is related to another variable which in turn is related to the general environment. The methodology is exemplified by a case study on springs price forecasting. In the spring price estimation process different elements are considered, such as: the shape and the size of the items, the production costs, the profit margin practiced by the manufacturing company, the utility of the item etc.
Hybrid welding of steel 4330V
Authors: Żuk M , Wyględacz B , Stano S 
Published: September 2020

Abstract
The article describes the hybrid welding process (Laser-MAG) of 4330V steel. This steel is a high-strength, micro-alloy material with tempered martensite structure. The microstructure of tempered martensite is obtained through the heat treatment process and through the vanadium micro-additive. Due to the high carbon content (approx. 0.3%), this material causes problems during welding and requires heat treatment before and after welding. The material’s high strength and plastic properties make this material desirable on the market. Hybrid welding is a process of joining materials, where a laser beam is used to achieve deep penetration into the material, and the use of a MAG welding source results in an additional electric arc that supports the melting process of the base metal and the additional material completes the weld. Using a robotic station for hybrid welding, a 11mm thick butt joint was made of 4330V steel without heat treatment processes before and after welding. The joint was welded from two sides. After welding, a number of tests were performed to determine the properties after welding. Visual and penetration testing, macro and microscopic tests, Vickers hardness test, tensile strength test and bending test on both sides were performed. The tests showed a properly made joint with numerous splashes, but unfortunately transverse cracks in the weld were detected which resulted from the stretching of one weld by the other. Macro and microscopic examinations revealed the correct execution of the joint on a full penetration cross-section, the martensitic structure in the heat affected zone and in the weld was visualized. Destructive testing revealed, among others, an increase in hardness in HAZ (Heat affected zone) to a level of about 500HV, high tensile strength at the level of the base metal. The cracks formed on the face mean that the welding process needs to be refined to eliminate such defects.
Technical solution for supplying a solvent of asphalt-resin-paraffin deposits (AFS) to a tubing string of oil wells equipped with electric centrifugal pumps.
Authors: Cheban S.E. , Valeev M.D. , Leontiev S.A. , Mayer A.V. , Samoilov A.R. 
Published: September 2020

Abstract
For prevention and combating paraffin deposites different chemical regents are widely used (ihibitors and AFS solvents). In field conditions many ways of chemical regents dosing are applied. Injection of chemical reagents in oilwell tubing is the most effective for ARPD solvents; in this case consumption of reagents is largely decreasing by comparison with chemical reagents dosing through the well-casing annulus. The article describes design and operating processes of technology of ARPD-solvent dosing in electric centrifugal well pumps installation. This process opens fluid access to oilwell tubing at higher pressure at the wellhead. Reagent RT-1-3, is used as aromatic ARPD solvent. In RT-1-3there is butylbenzene fraction of Kazan Production Association Orgsintez containing a mixture of butylbenzene, isopropylbenzene and polyalkylbenzene.
Centrosymmetric and acentric whitlockite-type phosphates and vanadates among Ca3(VO4)2-Ca3(PO4)2-Y2O3 compositions
Authors: Deyneko D V , Titkov V V , Aksenov S M , Yu Stefanovich S , Lazoryak B I 
Published: September 2020

Abstract
Identifications and studies of whitlockite-type phases for the first time are fulfilled in the cation-anion mixed phosphate-vanadate ferroelectric systems Ca10.5(V1-x
P
x
O4)7, Ca9Y(V1-x
O4)7, Ca10.5-1.5x
Y
x
(VO4)7 and Ca10.5-1.5x
Y
x
(PO4)7. These systems are the sections of a more extensive multi-component system Ca3(VO4)2 - Ca3(PO4)2 - Y2O3, but are all built on the basis of well-known individual compounds of the type of mineral whitlockite. The solid solutions formed between them are also of ferroelectric whitlockite-type, but some compositions are not ferroelectric, and according to the nonlinear optical phase analysis possess centrosymmetric structure. Ferroelectric phase transitions were detected in the region of 1000–1300 K by the method of dielectric spectroscopy. A precision X-ray study of some compositions of solid solutions using synchrotron radiation revealed a significant deviation in the cationic-anionic arrangement from being completely disordered. Partial ordering of structural tetrahedral groups of PO4
3- and VO4
3- determines a significant increase in nonlinear optical activity in the mixed anions whitlockite-type compounds.
About use of supercapacitors in autonomous power supplies
Authors: Ganiev M I , Dyomko A I , Yu Semenov O 
Published: September 2020

Abstract
The article describes the use of supercapacitors in power supplies designed for a long time of unattended operation in difficult meteorological conditions. A comparison is made of the energy efficiency factor of energy storage devices - batteries and supercapacitors when using solar panels. The optimization of the power supply circuit is considered, taking into account the provision of the maximum battery life with a limited number of charge / discharge cycles.
Determination of the Geological Age of Oil Using Diamondoids
Authors: Giruts M , Gadzhiev G , Gordadze G 
Published: September 2020

Abstract
Based on the study of a large number of Western and Eastern Siberia oils, it was shown that adamantanes can be used as a means of correlation in oils of different genotypes and ages. Based on the relative distribution of mono-, di-, and trialkyl-substituted C11–C13 adamantanes marine and terristerial oils and Cenozoic and Proterozoic oils were distinguished. This approach could be used when there are no generally recognized biomarker hydrocarbons or indicators based on them are uninformative. We found that Jurassic and Cretaceous oils of Kalmykia can be distinguished by the distribution of methyl- and dimethyldiamantanes. It was concluded that the distributions of alkyl substituted diamantanes could also be applied for the differentiation of oils of different ages.
Permeability Alteration of Carbonate Reservoir Rock Under Cyclic Geomechanical Treatment
Authors: Indrupskiy I M , Ibragimov I I , Zakiryanov R A , Idiyatullin I F , Girfanov I I , Remeyev M M , Mansurov A 
Published: September 2020

Abstract
The paper presents integral analysis of data obtained on carbonate reservoir rocks of Bashkir and Tournai formations (Republic of Tatarstan, Russia) under specially designed experimental studies for measuring rock permeability alteration under changes of pore pressure with constant triaxial outer (geostatic) stresses. Characteristic hysteretic effects of permeability alteration under cyclic changes of pore pressure are revealed and related to the reservoir and mechanical properties of rock samples, as well as different fluid saturation. It is shown that cyclic geomechanical treatment can promote significant improvements of flow characteristics of a carbonate rock material.
Innovative Approach to Assessing the Condition and Certification of Oil-Contaminated Sites
Authors: Mukhametshina E R , Aitov I S 
Published: September 2020

Abstract
The article describes an innovative method of volumetric assessment and certification of oil-contaminated land plots, which allows us to give an accurate assessment of the volume content of certain limiting factors. This technique involves building 3D models, tabular systematization of concentrations and volumes of oil pollution, improving the certification of the above-mentioned areas using special QR codes and parcel codes created by us. The method described by us makes it easier and at the same time increases the objectivity of certification of oil-contaminated land plots, reflects the qualitative and quantitative volume and time parameters of plots, increases the convenience, efficiency and reliability of accounting, data transmission and storage.
Interference analysis of wells in oil and gas reservoir with bottom water
Authors: Ryzhova LL , Kanevskaya R D 
Published: September 2020

Abstract
A mathematical model of the inflow and algorithm for calculating the pressure field for interfering wells in a complex oil and gas reservoir with bottom water were developed in this paper. The interference model explores well interaction and when the operating mode of one of them is changing it allows to evaluate the change of bottom hole pressure in the reacting wells. While using the developed model it is possible to calculate a pressure field for a group of wells, to simulate the process of pulse-code well testing and also to specify the boundary conditions for more detailed inflow models. All the results were successfully tested on real data from one of the Eastern Siberia fields.
Effect of fertilization practice on biological properties of crude oil-polluted soil
Authors: Wei X , Bocharnikova E A , Matichenkov V V , Demin D V 
Published: September 2020

Abstract
Hydrocarbon soil pollution is widespread problem in many regions of the world, where oil is extracted and transported. Pollution with crude oil has numerous adverse impacts on the soil-microorganism-plant system. Although adding fertilizers has been shown to be essential to enhance remediation rate, excessive nutrients may exert toxicity for microorganisms and plants. Field test was conducted in the area previously subjected to several accidental oil spills in the central European Russia. The effects of fresh pig manure and/or conventional NPK fertilizers on plant growth, hydrocarbon content and activities of catalase, dehydrogenase, urease, sucrose, and phosphatase were evaluated depending on an application rate. Fertilizer application resulted in restoration of plant cover and reduction of hydrocarbons by 13 to 46%. Oil pollution reduced activities of catalase, dehydrogenase, sucrase and phosphatase and increased urease activity. Manure application was more effective in regard to plant growth, hydrocarbon removal and enzymatic activity in comparison with mineral fertilizers. The maximum positive effect on contaminated soil-microorganism-plant system was obtained under combined application of manure and NPK.
An intervening metallic phase at the CDW–SDW transition region in the one-dimensional Holstein-Hubbard model at half filling: a semi-exact solution
Authors: Malik M Zahid , Chatterjee Ashok 
Published: September 2020

Abstract
The one-dimensional Holstein–Hubbard model is analyzed at half filling at the CDW-SDW transition region by using a series of unitary transformations. The phonon degrees of freedom are eliminated by averaging the transformed Hamiltonian with respect to a generalized many-phonon state and the resulting effective electronic Hamiltonian is finally solved exactly by employing the Bethe-ansatz technique. The present variational state leads to a lower ground state energy as compared to those obtained from the previous variational calculations and yields a wider intermediate metallic phase at the SDW-CDW transition region confirming the prediction of Takada and Chatterjee.
Analysis of the high-speed rotary motion of a superconducting magnetic bearing during ring spinning
Authors: Sparing Maria , Espenhahn Tilo , Fuchs Günter , Hossain Mahmud , Abdkader Anwar , Nielsch Kornelius , Cherif Chokri , Hühne Ruben 
Published: September 2020

Abstract
Ring spinning is the leading textile technology for the production of short staple yarn, which runs commercially up to a maximum speed of 25 000 rpm. Higher speeds result in yarn damage mainly due to frictional heat. To eliminate this limitation, a friction-free superconducting magnetic bearing (SMB) was introduced as alternative high-speed yarn twist element consisting of a cryostat with an array of superconductors and a levitating permanent magnet ring with a yarn guide. Whereas stable spinning was possible until 30 000 rpm, it turned out that the new SMB twist element is more susceptible to external disturbances resulting in oscillating movements of the magnet. Therefore, a measurement system with an array of 5 synchronized optical laser triangulation sensors and one tachometer was implemented to analyse this motion in detail during spinning with high speeds. To test the system, the spinning speed was varied between 10 000 rpm and 21 000 rpm for different yarn qualities. In general, the magnetic ring oscillates around its centre position with the rotation frequency and a peak amplitude between 10 μm and 14 μm, which might be due to a small imbalance of the magnet. At the same time, the small tilt of the ring remained fixed with respect to the machine for all speeds. In addition, larger oscillation amplitudes of up to 300 μm are observed at 18 Hz for selected spinning parameters arising most probably from resonance effects with machine vibrations.
Influence of the base material on the interface properties of ZnO:Al/n-CdS/p-Cd1−xZnxTe heterojunctions
Authors: Maistruk Eduard V , Ilashchuk Mariya I , Orletsky Ivan G , Koziarskyi Ivan P , Koziarskyi Dmytro P , Marianchuk Pavlo D , Parfenyuk Orest A , Ulyanytskiy Kostyantyn S 
Published: September 2020

Abstract
Researches of I–V-characteristics and C-V-characteristics of structures fabricated on unannealed and annealed at high temperature (t = 900 °C) p-Cd1−xZnxTe substrates have been carried out. The influence of the intrinsic point defects system of the base material p-Cd1−xZnxTe on the interface properties of ZnO:Al/n-CdS/p-Cd1−xZnxTe heterojunctions have been studied. The above structures have been fabricated by sequential deposition of CdS and ZnO:Al thin films on crystalline p-Cd1−xZnxTe by high-frequency magnetron sputtering. Based on the analysis of the I–V-characteristics in the region of forward and reverse biases, the relationship between the physical processes during heat treatment and the structural perfection of the transition area of the studied heterojunctions have been established.
Evaluation of a Text Messaging-Based Human Papillomavirus Vaccination Intervention for Young Sexual Minority Men: Results from a Pilot Randomized Controlled Trial
Authors: Gerend Mary A , Madkins Krystal , Crosby Shariell , Korpak Aaron K , Phillips Gregory L , Bass Michael , Houlberg Magda , Mustanski Brian 
Published: September 2020

Abstract

Background
Men who have sex with men (MSM) are at high risk for human papillomavirus (HPV) infection and HPV-related anal cancer. Although a safe and effective vaccine is available to prevent HPV infection, HPV vaccine uptake among young MSM remains low.

Purpose
This pilot randomized controlled trial tested the acceptability, feasibility, and preliminary efficacy of a text messaging-based HPV vaccination intervention for young sexual minority men.

Methods
In 2018, unvaccinated sexual minority men aged 18–25 years were recruited from Chicago to participate in a 9 month sexual health program called txt2protect. Participants (N = 150) were randomized to the intervention or control condition. Intervention condition messages focused primarily on HPV vaccination, with only a brief mention of other sexual health practices (e.g., condom use and HIV testing), while control condition messages focused on a variety of sexual health practices with only a brief mention of HPV vaccination. Participants received daily text messages for the first 3 weeks and monthly text messages for the remaining ~8 months of the trial. Participants completed surveys at baseline and 3 week and 9 month follow-ups.

Results
Participants reported high satisfaction with the intervention. Although trial retention was high (with over 88% completing the 9 month survey), the study fell short of meeting its recruitment goal. HPV vaccine series initiation was significantly higher among intervention participants (19.4%) compared to control participants (6.6%), odds ratio = 3.43, 95% confidence interval: 1.17, 10.08.

Conclusions
Findings suggest that txt2protect is an acceptable and potentially promising intervention for increasing HPV vaccine initiation among young sexual minority men.

Clinical Trial Registration
NCT02994108.
Predicting Social Distancing Intention and Behavior During the COVID-19 Pandemic: An Integrated Social Cognition Model
Authors: Hagger Martin S , Smith Stephanie R , Keech Jacob J , Moyers Susette A , Hamilton Kyra 
Published: September 2020

AbstractBackgroundSocial distancing is a key behavior to minimize COVID-19 infections. Identification of potentially modifiable determinants of social distancing behavior may provide essential evidence to inform social distancing behavioral interventions.PurposeThe current study applied an integrated social cognition model to identify the determinants of social distancing behavior, and the processes involved, in the context of the COVID-19 pandemic.MethodsIn a prospective correlational survey study, samples of Australian (N = 365) and U.S. (N = 440) residents completed online self-report measures of social cognition constructs (attitude, subjective norm, moral norm, anticipated regret, and perceived behavioral control [PBC]), intention, action planning, habit, and past behavior with respect to social distancing behavior at an initial occasion. Follow-up measures of habit and social distancing behavior were taken 1 week later.ResultsStructural equation models indicated that subjective norm, moral norm, and PBC were consistent predictors of intention in both samples. Intention, action planning, and habit at follow-up were consistent predictors of social distancing behavior in both samples. Action planning did not have consistent effects mediating or moderating the intention–behavior relationship. Inclusion of past behavior in the model attenuated effects among constructs, although the effects of the determinants of intention and behavior remained.ConclusionsCurrent findings highlight the importance of subjective norm, moral obligation, and PBC as determinants of social distancing intention and intention and habit as behavioral determinants. Future research on long-range predictors of social distancing behavior and reciprocal effects in the integrated model is warranted.