bluuebunny/crossref_metadata_2025_split huggingface dataset:
Behaviour of calcined gypsum-based materials during setting
Authors: Dolezelova M , Jerman M , Vimmrova A 
Published: August 2019

Abstract
The behaviour at early age of several composed gypsum-based materials was investigated. The binary binder, composed of calcium sulphate hemihydrate and slaked lime, several ternary binders with different types of pozzolans were prepared, and their behaviour during setting was studied. Unrestrained volume changes of calcium sulphate-based pasts were measured by displacement of liquid, in which the specimens were submerged. The hydration heat of composed binders was measured by isothermal calorimetry. The behaviour of composed materials with different types of pozzolans was compared with the behaviour of calcined gypsum.
The assessment and prediction of concrete sustainability
Authors: Vymazal T , Teply B , Hrabova K 
Published: August 2019

Abstract
The sustainability of concrete and concrete structures is seeing increased attention; among other things, this is because 5% of global CO2 emissions are produced by cement manufacturing. Responsible sustainability management requires effective tools for the quantification, i.e. measurement, or comparison of material, technological, and structural options. This is why there are a number of initiatives and approaches that aim to reduce global greenhouse gas emissions. Their project design uses techniques that assess whole structures and their usage; however, most of their input data is based on estimates. This paper presents a validation of a method of designing, assessing, and predicting sustainability for one material (concrete) with regard to its composition, relevant properties, and predicted value dispersion utilizing probabilistic approach.
Thin films deposition on 304L stainless steel using e-gun technology for medical applications
Authors: Baila D , Tonoiu S 
Published: August 2019

Abstract
The purpose of this article is to characterize surface of 304L stainless steel coating by e-gun technology with thin films of Ta2O5 and ZnO. ZnO films are used in pharmaceutical industries, in cosmetics and in medicine, grace of their better anticorrosive, antibacterial and photo catalytic properties. Ta2O5 films have rapidly evolved in medicine research with the promise of development of new types of biomaterials used in medicine. Ta2O5 coatings present an excellent biocompatibility, good dielectric properties, and high corrosion resistance. The biomaterials are realized by novel and special methods to resist of the biological reactions that occur in medical implants (protein adsorption, cell adhesion, cell growth, blood compatibility, etc.). The most important surface properties are physical properties, durability and biocompatibility. The physical properties of a biomaterial that must to be measure, are mechanical strength, permeability and elasticity. Biocompatibility is the response of the biomaterial or of the device to the proteins, cells and organisms action, when the implants are in contact with the biological tissue. The common method to characterize biomaterial surfaces are: contact angles, ESCA (XPS), Auger Electron Spectroscopy, SIMS, FTIR-ATR, STM, SEM and EDAX.
An approach with genetic algorithms to improve the workstation space planning
Authors: Belu N , Nitu E L , Gavriluta AC , Ionescu L M 
Published: August 2019

Abstract
Industry 4.0 is characterized by the use of digital solutions and computational technologies. The proposed paper presents a workstation space plan solution using an intelligent computational approach: Genetic Algorithms. On the one hand, we have the operator’s effort represented by the motion trajectories in the normal work area. On the other hand, the production flow requires some constraints on the sequence of the assembled components or their location. Considering both the constraints and the reduction of the operator’s effort, the planning solution proposed in this paper ensures the improvement of the working process by applying the principles of motion economy under the conditions of the constraints required by the production process. The resulting sequence and type of the components and operator effort for the production process is indicated to the operator on the modular workstation. Furthermore, the component placement can be adapted to the characteristics of the production process or of the operator’s needs (left handed, has some disabilities, etc.). The solution proposed in this paper was applied in an experimental laboratory where components from the automotive industry are assembled.
Some aspects of prototyping oversized parts through PolyJet technology
Authors: Carausu C , Negru R , Serban D A , Turc C , Belgiu G 
Published: August 2019

Abstract
The paper presented a series of experiments to improve the performance of rapid prototyping processes. The paper presents aspects regarding the realization of polymeric parts by PolyJet rapid prototyping technology. Achieving oversized parts on printers whose print size is small is subject to additional demand for the designer and the technology engineer who designs the printing strategy. Small parts segmentation is a solution, provided that after gluing the parts with adhesives recommended by the manufacturer, the general assembly acts as a one-piece piece – this is the ideal case. An acceptable solution is that the overall assembly has at least 70-80% of the properties of a part made up of a single piece. In the present work several sets of specimens were used for the experiment and they were joined together. Their properties were compared to one-piece specimens. Finally, the useful conclusions for designers and technologists are presented.
Thin coatings for pumping station mechanical components
Authors: Paleu C Cirlan , Paleu V , Istrate B , Cimpoesu N , Munteanu C 
Published: August 2019

Abstract
The pumping stations are key points of water treatment plants, their performance directly affecting the serviceability of the entire water treatment system. The excessive wear of mechanical components conducts to pumping station out of service state. The deposition of thin coatings on the elements subjected to wear can generally extend the operating time of the water treatment plants. The paper analyses the failure modes of the mechanical components of the pumping stations and the existing efficient solutions for thin coating deposition to protect them from excessive wear. Consequently, an effective coating is deposited on the raw metal by Atmospheric Plasma Spraying (APS) and tribological tests are developed for an initial assessment of the anti-wear properties of the coating. The worn contact surfaces are analysed by Scanning Electron Microscopy (SEM) and the chemical composition is established by Energy-dispersive X-ray spectroscopy (EDS). The tests are still in development, revealing that the main failure modes of the coating are abrasive wear and delamination. Future research will be conducted to identify the best combination of powders for a multiple layer deposited coating with high wear resistance.
Manufacturing analysis with discrete events using IoT platform
Authors: Ciortea E M 
Published: August 2019

Abstract
The paper presents how to integrate cloud systems and access them with IoT devices. The IoT platforms addressed in the paper are Platform as a Service (PaaS) and Software as Service (SaaS). The analysis is presented by modeling a case study for systems with discrete events. Because the general system is analyzed as a cloud system on levels, we will leave the general system as stochastic.Qualitative analysis has the role of checking the structural and behavioral properties of the system, the existence of bottlenecks, bridging, and security systems. The quantitative analysis measures the specific performance of the manufacturing system. The results show that this approach can be used to detect jams in the system. Thus, manufacturers can resize production capacity and optimize even the entire manufacturing system.
Study of some heat treatment effects on thermodynamic and structural properties of Ti-Ta biomedical shape memory alloys
Authors: Costache C , Apostol V , Pricop B , Lohan N-M , Comaneci R I , Bujoreanu L-G 
Published: August 2019

Abstract
The shape memory effect (SME) in binary β-Ti alloys is associated with a reversible martensitic transformation from α”- orthorhombic martensitic phase to β-bcc austenitic phase. The present paper reports the experimental results obtained on TiTa alloys, containing 25, 30, 35 and 50 mass % Ta. The specimens were processed from as-cast levitation induction melt ingots, cut by wire electric discharge, hot/cold rolled (enabling to obtain 500-mm long thin ribbons), solution treated (900°C/30 min/water quenched, W.Q.) and aged (300°C/1 h/W.Q.). From each heat treated state, samples were cut for tests meant to emphasize the presence of thermal and mechanical memory behaviour. Thermal memory was highlighted by SME-work generating training cycles, investigated by cinematographic analysis. The respective results were corroborated with those recorded by dynamic mechanical analysis (DMA). Mechanical memory was revealed by winding-unwinding and tensile tests. The winding and tensile tests offered information about the capacity of cold rolled ribbons to memorize their room temperature (RT) profile. Tensile tests were applied up to complete failure or by RT loading-unloading cycles.
The influence of the surface preparation of aluminium alloys for brazing upon the hardness of the assembly
Authors: Dimitescu A , Alecusan AM , Babis C , Dascalu L 
Published: August 2019

Abstract
The wider use of aluminum and its alloys also involves specific technologies for reconditioning and repairing the various components. Specialist studies have shown that a more advantageous technique, from an economical point of view, than welding with less polluting and good mechanical properties is brazing. The only disadvantage of this process is the stage of preparing the surfaces to be assembled.
Specialty literature and many published papers provide detailed information with direct reference to the mechanical and physical properties of aluminum alloy assemblies refurbished by brazing depending on the surface preparation mode.
The present paper aims to make a study, based on experimental data, on how the surface preparation influences the hardness of aluminum alloy assemblies refurbished by brazing. The areas of the base materials, the filler material as well as the thermal diffusion zones resulting from the brazing operation will be studied.
The main problem is the difference in hardness between the materials to be assembled and the material with which they are assembled. This can be a major cause, which can generate defects in operating cycles by lowering the strength of the assembly. By choosing an optimal surface preparation technology, we can reduce these differences by obtaining an assembly with uniform properties in all its structure, so with a longer service life.
Sustainable anti-corrosive protection technologies for metal products by electrodeposition of HEA layers
Authors: Florea R M , Carcea I 
Published: August 2019

Abstract
The purpose of this paper is to study the electrochemical synthesis of thin films of multi-component alloys with improved structures and properties to ensure optimal protection of metallic materials used in extreme environments against various types of corrosion, oxidation and wear. Electrochemical deposition is an inexpensive alternative to thin film synthesis because it does not require complex or costly equipment and uses readily available raw materials. This simple method offers the possibility of depositing thin layers on substrates of complex geometry and can be achieved at low process temperatures with reduced energy consumption. Electrodeposition allows easy control of chemical composition, morphology and thickness of coatings by varying deposition parameters. HEA alloys are usually developed by physical methods, most commonly by casting-melting. Mechanical alloying and rapid solidification are other synthesis processes used to obtain structural materials. HEA coatings have also been obtained by various deposition methods, such as magnetron-sputtering and laser deposition. In this paper is investigated the microstructure, mechanical properties and oxidation behaviour of HEA coating obtained by electrochemical deposition.
Effect of grain refinement on mechanical and corrosion behavior of AZ91 magnesium alloy processed by ECAE
Authors: Gajanan M N , Narendranath S , Satheesh Kumar S S 
Published: August 2019

AbstractAZ91 Mg alloys were processed by equal channel angular extrusion (ECAE) up to 4 passes through route-R. The increase in number of ECAE passes to yield fine-grain structure in the bulk Mg alloy with a more dislocation density, this enhances mechanical properties and corrosion resistance. Indeed, microstructural observations revealed an equiaxed and significant grain refinement after ECAE-4P, with a mean grain size (d) of ∼ 4.36μm. Further, the tensile strength, micro-hardness and corrosion resistance were also increased, however the elongation was reduced with the increasing of ECAE passes. The electrochemical polarization test in 3.5wt % NaCl solution revealed a noticeable enhancement in the corrosion resistance of ECAE processed AZ91 Mg alloy compared with the as-received Mg alloy. This is mainly due to grain refinement and distribution of secondary phase particles in Mg alloy matrix during ECAE-4P.
XPS, XRD, and SEM characterization of the virgin and recycled metallic powders for 3D printing applications
Authors: Gorji N E , O’Connor R , Brabazon D 
Published: August 2019

Abstract
We characterized the surface and microstructure of both feedstock (virgin) and recycled Stainless Steel 316L powders used for selective laser melting process. Reusing the recycled powders can significantly reduce the powder consumption, production cost and time. We have performed X-ray photoemission spectroscopy (XPS), Scanning electron microscopy (SEM), X-ray Diffraction (XRD) and rheology analysis on steel powders both on the virgin powder and the powders not adhered to the printed parts but recycled in the powder bed. The results confirm that the oxygen level on the surface of the recycled powder is increasing and the metallic oxides diffuse out to the surface of the powder particles during the manufacturing process. Nevertheless, the changes are not significant which promise the reusability of the recycled powders for several cycles. We observed no change on the phase of the recycled powder. Further characterizations are ongoing to measure the chemical composition and morphology of both virgin and recycled powders to correlate them with the mechanical properties of the printed parts. These characterizations allow extending the powder reuse for a number of reusing cycles and reducing the manufacturing time and cost without reducing the mechanical properties of the final parts.
Thermal cutting of thermomechanically rolled S700MC and heat-treated S690QL steels
Authors: Gorka J , Poloczek T 
Published: August 2019

Abstract
The article describes the impact of oxygen, HD air plasma and laser beam cutting processes on structural changes and quality of the surface of thermomechanically treated S700MC and heat-treated S690QL steels. Taking into account good quality of obtained cut surface, particular attention shall be attached to the structural and chemical changes due to the impact of the heat cycle. Those modern steels are especially susceptible to a loss of their properties during the heat interaction in thermal cutting processes. The quality of the surfaces after thermal cutting processes were evaluated in accordance to ISO 9013:2017 (bevel angle, surface roughness, rectangularity tolerance). Also, measurements of cut widths and breakthrough holes diameters were accomplished. In the next stage the hardness measurements and metallography examination were performed. The following devices were used for this purpose: metallographic light stereoscopic microscope Olympus SZX9 and Wilson Wolpert 401 MVD for Vickers’s hardness measurements.
Developing structures for the construction of the processing equipment - Case study
Authors: Iordache M D , Costea A , Malea C , Nitu E , Rizea A 
Published: August 2019

Abstract
The evolution of the manufacturing processes requires, as a mandatory condition, to increase the performance of the technological equipment for processing, assembling and control, by promoting new solutions in the field of devices of the semi-finished products, but also by developing special or modular multifunctional components for the modernization of machine tools. This paper proposes a method of optimization of the technological process and equipment, which in the first stage determines, on the basis of a technological chart, the optimal sequence and the number of operations or phases of processing, and in the second step with the global utility method, the optimal combination of special or modular structures, from existing or new ones, is determined for the construction and configuration of a flexible multislot machine for simultaneous and successive centring and spherical operation. We believe that the creation of tools, devices for orientation and fixing, tooling, support, guidance, reinforcing and transfer blanks and modernization of machine tools, is an important measure to streamline manufacturing systems involving important material effort. Our theoretical and experimental research and industrial applications in recent years aim to develop new structures, processing systems and equipment with features, performance and especially flexibility, superior to existing ones.
Investigation of machining parameters on corner accuracies for slant type taper triangle shaped profiles using WEDM on Hastelloy X
Authors: Manoj I V , Joy R , Narendranath S , Nedelcu D 
Published: August 2019

AbstractWire electro-discharge machining (WEDM) is a widely used machining process for machining of difficult to cut materials, which are used in precision profile applications like dies, metal stampings, and gas turbine parts. In the present research work, a new slant type taper fixture was used to obtain angular machining of triangular shape slots of sides 1mm, 3mm and 5mm machined both in 0° and 30° as slant angles on Hastelloy X. The corner radius and corner errors were investigated for different machining parameters like corner dwell time (CDT), offset distance (WO), wire guide distance (WGD) and cutting speed override (CSO) using L16 orthogonal array for both the slant angles. SEM micrographs indicated that corners were with lower radii at 30° than in 0° slant profiles, at lowest and highest cutting speeds. The main effects plot showed that the corner radius increases with the increase in wire offset and wire guide distance parameters. The increase in corner dwell time has an adverse effect on the corner radius. The triangles were machined at different cutting speeds from 0.47 to 1.51 mm/min with various parameters; it was observed that as the corner radius decreases the corner error also reduces. However, the corner radius and corner error can be minimized by selecting an optimized cutting parameter.
Experimental results regarding industrial filtration using ultrasonic filters
Authors: Nitoi D , Amza Gh , Petrescu V , Zoia A , Petriceanu C 
Published: August 2019

Abstract
The paper presents general description of an ultrasonic air filter used in industrial air filtration system and the experimental results obtained. The method can be used in air purification system from the highly polluting processing technology of an industrial shop (paint shops, foundries, welding constructions, forging, etc.). The ultrasonic system construction and the advantages of using ultrasounds in the pollutant air filtration and purification process and an ultrasonic filter designed are here presented. In this case, the transducer which is the most important element consist in two asymmetrical passive elements (reflector and radiant element). For the ultrasonic system design there are presented the principal theoretical elements and in the final the finite element analyze of the whole ultrasonic system. To start a different filtering system some considerations like the following are important: the construction should be as simple and easy to install in the working zone, do not require dismantling to clean the filter element, cleaning periodically when the pressure drop reaches a limit value by commanding the operation of the ultrasonic transducer, allow restraint of the finest particles leading to the final consumer (in some technological processes) pure air, have a much longer operating life than conventional filters, in the sense that the ultrasonic activated filter elements have a higher reliability, to achieve a pressure drop in a range of restricted values, practically to be kept constant or with very small variations, creating stationary waves to allow not only very fine particle retention but also air drying, allow easy maintenance, the operating costs of which do not exceed the costs of the classic ones.
Study of the influence of surface roughness parameters on the frictional characteristics of materials
Authors: Pena-Paras L , Maldonado-Cortes D , Martinez C , Arias M , Ontiveros A , Castanos B , Morales-Martinez M 
Published: August 2019

Abstract
The study of surface roughness parameters and their correlation with coefficient of friction (COF) is of great importance for metal-mechanic applications. Evidence suggests that Ra (surface roughness average) is not directly related to COF under sliding conditions. In this study, the relation between surface roughness parameters, namely Ra, Rt (maximum height of the profile), Δa (mean slope of the profile), and COF, as well as their interactions, were particularly studied. The materials were of an aluminium alloy Al A380. Samples were chemically attacked to modify their surface roughness characteristics. Six different conditions were tested: Al A380 with the surface attacked with an alkaline substance for 0, 2.5, 5, 15, 30 and 60 min. The value of COF was determined using a T-05 block-on-ring tribotester, and surface roughness data was obtained using an optical 3D surface measurement system. MathWorks MATLAB software was used to process the data. Results show that Δa has a strong positive correlation with COF during sliding conditions, whereas both Ra and Rt may vary without directly affecting COF, contrary to the commonly used industry standard.