bluuebunny/crossref_metadata_2025_split huggingface dataset:
Drop of Spin Polarization of Half Metal due to Interfacial Spin Mixing
Authors: Cahaya Adam B. , Majidi M. A. 
Published: October 2019

Abstract
Half metal is a ferromagnetic metal that act as a conductor to electrons with of one spin orientation, while act as an insulator for the opposite spin. Because of this high spin-dependent property, half metals are widely studied in spiritroriics area. This property can be represented by the spin polarization P = (G↑ — G↓
) / (G↑ + G↓
) of its spin-dependent conductances G↑,↓. The value of P of an ideal half metal is 1. However, the value of P is reduced when it is attached to other material. We study how the spin current generations that occurs at the interface of half metal and normal metal reduces the value P. At the interface of a half metal and a normal metal a spin current can be pumped from the ferromagnetic layer to the normal metal. This spin pumping effect is characterized by spin-mixing conductance, which represents the magnitude of the generated spin current due to the mixing of electrons with spin up and down. By analyzing the coupling of spin and electric currents in the interface of half metal and normal metal, we show that the spin mixing strongly influences the spin-dependent transport near the interface, and therefore reduces the spin polarization of the half metal.
Three Dimensional Numerical Modeling of Current and Temperature Distribution in the Estuary of Palu River
Authors: Lutfi Mohammad 
Published: October 2019

Abstract
Three dimensional numerical model of current and temperature distribution in the estuary of Palu river was discussed in this article. The simulation was conducted using estuary coastal ocean model and sediment transport (ECOMSED) and geographical information system (GIS). The first simulation was conducted by assuming no discharge and the second simulation using combination of tidal and river discharge. The first simulation runs smoothly, where the results revealed that the tidal current velocity on the horizontal and vertical cross sections for one tidal cycle ranged from 0 m/s to 0.03 m/s. Whereas a run time error occurred during the second simulation due to the calculation of nonliniear advection term parameter in momentum equation. The error problem could be solved by imposing a low river discharge data into the model. The visual appearance of current circulation at the river mouth, calculated surface elevation, and temperature distribution on the horizontal and vertical cross sections revealed a good agreement with the primary and secondary data.
The quality of the machined surface of an aluminum alloy depending on the cutting depth variation
Authors: Țîțu A M , Pop A B 
Published: October 2019

Abstract
The surface quality study of the cutting processes is a very current and complex subject, which approached in variously specialized researches. This paper is a continuation of our previous research. The primary objective of this paper is to track the evolution of the surface roughness measured longitudinally on the feed motion direction in the end-milling process of an aluminum alloy used in the aerospace industry. The active experiment is the research method used to achieve the proposed objective. The cutting regime adapted to carrying out the necessary experiments supposes a constant cutting speed, while the cutting depth varies with different values. Obtaining the experimental data did possibly using the roughness tester as a measuring device. The obtained measurements were used to determine the surface quality evolution in the various situations of the cutting regimes resulting from the combination of the process parameters considered in the analysis. The experimental study is very complex and carried in an industrial organization that focuses on the aerospace industry. Through this original research that was carried out in the smallest details, a series of comparative graphs of the surface roughness evolution performed under the cutting depth variation, which led to a package of conclusions to have taken into consideration.
Examination of the influence of cutting conditions on nano-metric face milling using MD models
Authors: Karkalos N E , Markopoulos A P 
Published: October 2019

Abstract
Machining is indispensable in the manufacturing sector for a wide variety of products. In the last years, the field of micro- and nano-scale manufacturing attracted a lot of interest, especially in high-end industries such as the biomedical and electronics industries. In order to improve the efficiency of these processes and understand the various underlying phenomena, it is important to develop relevant theoretical models. However, methods such as the Finite Element Method (FEM), which are well-established in the macro- or micro-scale level are not appropriate for creating models of nano-scale processes, as they treat the materials as continua. For that reason, the Molecular Dynamics (MD) method is usually used for simulations of nano-metric machining processes such as nano-milling. In the present study, a MD model of nano-milling is created and an investigation regarding the effect of cutting conditions such as feed rate and cutting speed on cutting forces, temperature and subsurface damage is conducted.
Effect of cooling condition over surface quality in turning of aluminium alloy 6082-T6
Authors: Beșliu I , Tamașag I 
Published: October 2019

Abstract
Cutting fluids play an important role in machining operations helping reduce friction, workpiece heating, tool wear and also with chips detachment and evacuation. The usage of cutting fluids also have a number of drawbacks that are related with the environmental threats and costs. Dry matching and MQL-minimum quantity of liquid seem to be promising solutions for these problems. But these solutions are not feasible under all machining applications. The present paper purpose is to investigate the effect of cutting and cooling conditions over surface quality in aluminium alloy 6082-T6 turning operations.
Experimental research of tool axis inclination angle influence upon surface roughness in ball-nose end milling of polyetheretherketones (Tecapeek natural)-Part I
Authors: Paşca I , Lobonţiu M , Bǎnicǎ M , Tǎmaş I 
Published: October 2019

Abstract
In order to find solutions for different medical applications like implants and reconstructions in clinical dentistry, orthopaedic or spinal implants, the polyetheretherketones have achieved a remarkable application because of their properties. The polyetherketone materials combine excellent wear resistance with very good mechanical properties, even under thermal load. Because of these qualities it is used also in different applications in automotive, aerospace and food industry. For each application, no matter if the process to obtain different shape is extrusion, injection moulding or machining by turning or milling, the surface roughness value is critical. For pieces with complex surfaces some finishing operations are necessary. The ball nose end milling process is recommended in this case because of its versatility. In ball nose end milling process the influence of tool axis inclination angle has a big influence upon surface roughness value. In this way theoretical studies are required in order to establish the influence of this parameter upon effective cutting speed. Also, experimental research method was needed in order to establish the quality of surface in terms of surface roughness. The experimental research results establish the most favourable values of inclination angle for Tecapeek-natural material in comparison with C45 material.
The in-plane compression performance of hierarchical honeycomb additive manufactured structures
Authors: Mansour M T , Tsongas K , Tzetzis D. , Antoniadis A. 
Published: October 2019

Abstract
Fused Deposition Modelling (FDM) is a simple additive manufacturing (AM) technology utilising fine filament extrusion of mainly thermoplastic materials to build 3D objects layer by layer. The focus of this paper is firstly to design hierarchical honeycombs and secondly to fabricate such structures using FDM with polylactic acid (PLA). The manufactured hierarchical honeycombs were tested under compression. The compression performance of the hierarchical honeycombs was assessed also with finite element analysis and the results were compared with the experimental derived properties in order to elucidate the mechanical behaviour of such honeycomb AM structures. The results reveal that for the 2nd order hierarchy of honeycombs the stiffness and the strength are increased in comparison with the 0th and the 1st hierarchies.
Research on manufacturing of pyramidal frustum parts using single point incremental forming process
Authors: Nasulea D , Oancea G 
Published: October 2019

Abstract
The incremental sheet metal forming is a flexible “die-less” process used to manufacture sheet metal parts in cold pressing domain. Especially talking about single point incremental forming, it is a process which does not require a special die to allow the sheet metal forming. To implement this process, a fixing device and a simple rounded tool are needed. The paper presents some research on the influence of a support plate upon the parts dimensional precision. Because, the main advantage of single point incremental forming process is the flexibility, in experiments, a fixing device that it was initial designed for incremental deformation of frustum cone parts, is used to deform pyramidal frustum parts. Different configurations of pyramidal frustum parts are simulated using a finite element method and a special software tool named TMPG, to check if the sheet material, deep drawing steel DC05, can be deformed without fracture. The manufactured parts are measured using a 3D scanner, and a comparison with the 3D CAD models of the original parts is made.
Continuously pulsed electric field treatment chamber modelling and design
Authors: Shorstkii I , Sosnin M , Khudyakov D 
Published: October 2019

Abstract
The perspectives of pulsed electric field (PEF) application for rheological changes in plant materials and treatment chamber design are considered in current paper. By using some mathematical tools and experiments data, viscosity of transporting plant materials confirms proposed Bingham rheological model assumption. Experimental studies have shown the presence of structure formation in material supplied to the treatment chamber channel. An effect of PEF treatment, with changes of material structure and increasing of material plastic viscosity from 0.117 to 0.159 Pa·s for samples after treatment by a field strength of E = 8 kV/cm and the number of pulses n = 300 was found. Obtained results of pulsed electric fields application in continuously material flow can be used in pulsed electric fields technologies, equipment design and help to determine cost efficiency of treatment in industrial application.
Numerical simulation of Friction Stir Welding of three dissimilar aluminium alloys
Authors: Boșneag A , Constantin M A , Nitu E L 
Published: October 2019

Abstract
FSW process is increasingly required in industrial environment. This innovative process has a lot of advantages: can be performed without melting of material, uses a non-consumable tool, performed good mechanical properties, can weld dissimilar materials and have a low environmental influence. On the other hand, FSW process has several disadvantages: an excessive tool wear, weld speeds slower, expensive equipment and limitations for high melting temperature materials. To achieve the expected results during industrial applications, welding process behaviour must be properly understood. The Finite Element Simulation is a technique which would help to understand the process variation during the welding and the result could be used to notice the effect of process parameters on weld quality. In this study an attempt is made to develop a FE model using ABAQUS V6.13/Explicit with help of CEL formulation, Johnson-Cook material law and Coulomb’s Law of friction. The model will obtain a perspective on circumstance of processing before carrying out the welding process, would predict the effect of input process parameters on outputs parameters like: temperature. The simulation results are used to obtain the optimized process parameters. Numerical model validation is performed by comparing the value of temperatures from FE simulation with the experimentally recorded temperatures.
Surface modification to develop hierarchical micro/nano topography on titanium based medical implants
Authors: Strnad G , Jakab-Farkas L , Cazacu R , Russu O , Petrovan C 
Published: October 2019

Abstract
Self-organized nanostructured TiO2 layers were developed on micro rough planar, cylindrical, and threaded surfaces of Ti6Al4V alloy by electrochemical anodization (EA) performed in phosphate-fluoride solution (1M H3PO4 with different HF additions) by using different process parameters (electrolyte concentration, anodization potential U, potential ramp Ur, and sample rotational speed n). Optical microscopy and scanning electron microscopy (SEM) was used to evaluate the morphology of the oxide layers. Nanostructured oxide layers with nanotubes/nanopores internal diameter in 25-110 nm range were developed on surfaces with an initial micro rough topography (Ra = 0.5-2 µm, resulting by CNC turning or by sand blasting and acid etching - SLA). On planar surfaces, the optimal EA process parameters in our custom-built anodization cell are: 0.5 wt.% HF addition in electrolyte, U = 20 V, and Ur = 0.1 V/s - for turned surfaces, and 0.4 wt.% HF addition in electrolyte, U = 24 V, and Ur = 0.08 V/s - for SLA surfaces. For cylindrical surfaces the nanotubes were superimposed on micro rough surface by using 0.4 wt.% HF addition in electrolyte, U = 24 V, and Ur = 0.08 V/s. On threaded surfaces continuous nanoporous oxide layer covering all geometrical features-frontal apex, spiral channels, major diameter, minor diameter, thread flanks - was developed by using 0.4 wt.% HF addition in electrolyte, U = 24 V, Ur = 0.08 V/s, and n = 8 rev/min.
Survey on the kinematics of a 6RSS parallel robot based on manipulability indices
Authors: Milica L , Năstase A , Andrei G 
Published: October 2019

Abstract
The study of the kinematic performances of a parallel mechanisms an important aspect in terms of analysis and design. This paper presents a study on the kinematic manipulability and kinematic efficiency of a 6RSS parallel mechanism. The parallel mechanism consists of a fixed plate and a mobile platform connected by six independent kinematic chains. Each of the six kinematic chains has an actuated rotational joint and two spherical joints. The motion equations for the six kinematic chains of the parallel mechanism are defined when the characteristic point P moves on the spatial curve with constant speed. Based on the global Jacobian matrix determinant and the angular speeds of actuated arms was graphically represented the variation of the two kinematic indices. Kinematic indices allow for assessing the quality of the mechanism motion; they also help us avoid those critical configurations encountered in the case of parallel mechanisms.
Analyses and redesign of a technological device for automated assembly, using Design for Manufacturing and Assembly approach
Authors: Pișta I M , Nagîț G , Merticaru V , Rîpanu M I , Cucoș M 
Published: October 2019

Abstract
This paper aims to present a theoretical approach and a case study within a research upon product and process design methods in terms of manufacturing and assembly – supported by DFMA (Design for Manufacturing and Assembly) techniques. Application of the integrated design capabilities provided by DFMA approach is illustrated with a case study on the development of a technological device for automated assembly of an industrial electrical plug inlet. The analysis and redesign using DFMA philosophy and advanced 3D design capabilities provided by CATIA V5 is an advanced engineering method for designing an innovative product in order to simplify the product, to quantify improvements and to reduce manufacturing and assembly costs. The new design of the studied product has been compared with the existing one from the aspect of parts quantity, handling time, assembly time and design efficiency. Finally, the study presents also some related conclusions together with further research directions.
Personification of criterial resource validation and scientific and technical support for the life cycle of vertical transport
Authors: Prusov A , Sevryugina N , Ovsienko A 
Published: October 2019

Abstract
It has been proven that the vertical transport occupies a niche not so much technical objects, how many socially significant technological advances that provide comfort and accessibility for the population of different levels of mobility. Analysis of legal, regulatory documentation showed that the security and reliability of vertical transport is represented in the theory of risk as a scenario of possible events with a broad range of assumptions within the zone of progressing temporary uncertainty and coherence mechanism models of actual conditions (GOST r ISO 9000), in most cases, it is not. Evaluated scientific elaboration area studies in part integrity, functionality and consistency of the regulatory framework legal enforceability. The model of the complete life cycle of vertical transport. Algorithm of modal analysis of vertical transport parameters of criteria. Estimation of interference and strengthening process factors. Conducted simulation risk factor system the effects of vertical transport the negative socio-economic consequences. Proposed personalized predictive model of full life-cycle operation of vertical transport. Practical recommendations aimed at harmonizing the basic works on scientific and technical support and monitoring, simplification of the development programs of work, obtaining accurate and timely information on the state of vertical transport.
Making a device for forced crystallization in magnetic and electric environment
Authors: Mândrea L , Constantinescu C , Marosy Z 
Published: October 2019

Abstract
The Earth’s magnetic field is, besides its protective role, important in the biochemical structuring of the elements in the living, biological body. The permanent electric field that envelops the planet’s surface brings extra effervescence to life. The structure of different chemical and biochemical compositions is due to a cumulus of both magnetic and electric synchronous fields. In different parts of the globe there are different fields, and / or different angles of the field’s manifestation. These elements can or cannot bring about changes in the structuring of ionic, biological solutions, which the formed team intends to study. Making such an experimental device is difficult since magnetic and electrical field accuracy is required, as well as the smallest deviation possible produced by the surrounding equipment. The device will successfully simulate extreme areas found on Earth. The studies are a logical continuation of the experiments made beforehand, starting in 2010, which highlighted the structural changes that plants have when electrical and magnetic changes occur in the environment. The device is part of a project of the National Committee on Antarctic Research, supported by the Romanian Academy; part of the Strategic Plan for Antarctic Research 2016-2020, 4. Thematic Area - Frontier Science: Antarctica - Terrestrial Analogue for Outer Space.
Hydrothermal liquefaction of microalgae for biofuel production: the recycling of nutrients from an aqueous solution after HTL
Authors: Chernova N I , Kiseleva S V , Vlaskin M S , Grigorenko A V , Rafikova Y Y 
Published: October 2019

Abstract
Microalgae are an alternative source for the renewable biofuels production. One of the promising technologies of microalgae fuel production is the hydrothermal liquefaction (HTL) with obtaining bio-oil as the target product. We have carried out a number of experiments on the hydrothermal liquefaction the biomass of blue-green microalgae Arthrospira platensis rsemsu
1/02-P (collection of Renewable Source Energy Laboratory at Lomonosov Moscow State University). For the HTL of arthrospira biomass the reactor of the Institute of High Temperatures RAS have been used. The outputs of bio-oil, gaseous products, solid residue and aqueous solution were 34-46%, 12-18%, 26-30%, 10-24% respectively. The aqueous solution hydrothermal liquefaction is a by-product, it has a limited energy value and needs to be recycled. Aqueous solution contains the nutrients necessary for growing algae but in quantities that are orders of magnitude higher than the standard ones. Studies growth of different algae species in aqueous solution after HTL have shown that in order to prevent the growth inhibitors toxic effect intensive its dilution is necessary. Microalgae strains, which can be cultivated in 500-fold diluted aqueous solution (Galdieria sulphuraria rsemsu G-1, Chlorella vulgaris rsemsu Chv-20/11-Ps), have been experimentally selected. It allows partially recycling the by-product of bio-oil from microalgae
Mathematical modelling of the spatial efficiency of car parks
Authors: Boroiu A , Neagu E , Boroiu A A , Vieru I 
Published: October 2019

Abstract
One of the major urban concerns is the lack of parking places. The most appropriate indicator for assessing the spatial efficiency of the car parks is the unit surface. The largest space-saving resources to improve spatial efficiency belong to the large car parks in the distinct situations: for employees of a large company or for hypermarket customers. As a result, a mathematical model for access to the parking place by means of a single steering manoeuvre has been constructed, having the angle of inclination of the parking spaces as variable and the 95% percentiles corresponding to the overall current dimensions of the cars as parameters. In the case of customer parking, it was considered that it is necessary for the customers to have access to the trunk to pick up the purchased items from the shopping cart, so a specific arrangement of the vehicles on the parking places is required. The results confirmed the superiority, from the point of view of spatial efficiency, of the angled car parks as compared to the rectangular car parks. For the car parks angled at 45° - 60° it has been demonstrated that increases of more than 10% over rectangular parking spaces are achieved.
The potential of roofs in city centers to be used for photovoltaic micro-installations
Authors: Suszanowicz D , Ratuszny P , Wróbel R 
Published: October 2019

Abstract
Currently in Poland, power engineering based on hard coal and lignite plays the dominant role. This significantly impedes the attainment of 15% share of energy produced from renewable sources by 2020 and has a negative impact on air quality in Poland. A solution to this unfavourable situation may be to develop renewable dispersed energy with particular emphasis on installations using photovoltaic. Strongly urbanized areas have high electricity demand, and at the same time low availability of areas where it is possible to locate renewable energy sources. In this study, the possibility of using roofs of buildings in city centres for the purpose of photovoltaic micro-installation was analysed. A case study was carried out for two selected districts of the city of Opole. Opole has sunshine conditions which are representative for Poland. The analysis of photovoltaic potential of roofs in urbanised areas was carried out using geographical information systems (GIS). The analysis showed a high photovoltaic potential of the two selected districts of Opole: the potential to generate locally almost 25% of the electrical energy required. The proposed method of determining the photovoltaic potential of roofs in city centres can be used in Polish conditions, as well as in Central Europe.