bluuebunny/crossref_metadata_2025_split huggingface dataset:
Development of Rotary Wankel Devices for Power Generation
Authors: Sadiq Ghada A. 
Published: July 2020

Abstract
Rotary Wankel engine has been the subject of the research since it is introduction; it can work as combustion engines as well as compressors and expansion devices (turbine). A volumetric expander is an appropriate device used in a steam Rankin cycle for low power generation, consolidated heat, and power unit. Wankel expansion devices have significant advantages, such as compactness, almost no vibration, low cost, and noise. A computational fluid dynamics (CFD) is extended to be used ANSYS-Fluent 17.2 for simulation the flow in a single stage rotary expansion device and to investigate the expander’s power. The current study is compared with the published work (Mazda) for the volumes and power output of the rotary expansion devices and showed a good agreement. Wankel expander size of 118.5 mm radius of the rotor, the eccentricity of 17 mm, and rotor width of 69 mm is selected. Results showed the contours of pressure and temperature at any rotor angles to insure the design is performing as suspected. The power output is 27.416 kW for ports without valves while by using valves only in the inlet ports created 17.8 kW.
Investigation of Mechanical Behavior Of Fiber Reinforced Tire Rubber Composite
Authors: Saadoon Hanan Mohsin , Alassadi Abbas A. , Faleh Nadhum Mejbil 
Published: July 2020

Abstract
This paper consists of the recipe preparation of passenger tire tread, the recipe formula, properties of the materials (matrix rubbers and reinforcement), the technology of rubber processing, compression modulus, vulcanization, mechanical tests.
The rubber that used in this work were created from natural (SMR-20) and styrene-butadiene (SBR-1502) rubber. Fifteen carbon black (N375) versus load level (10-30-50-70-90) filled recipes with other compounding materials such as filler; vulcanizing agent (sulfur) and accelerator were formulated with the compound formulations. In this paper we improve mechanical properties through selection of suitable rubber blends and through selected carbon black.
Experimental study of Zn-water nanofluid heat transfer enhancement through an oval twin impingement jet
Authors: Balla Hyder H. , Kareem Zaid S. , Abdulwahid AmmarF. 
Published: July 2020

Abstract
An oval cross-sectional-area twin jet were studies experimentally studied under constant heat flux conditions to clarify the effect of both Zn-water nanofluid along with such oval twin jet on the thermal characteristic and provide the lack data in such field. The validation was conducted with comparable study and it showed acceptable deviation. The emerged results referred to that the Nusselt number is remarkably increase as the nanoparticle concentration, Reynold number and the distance between nozzles increase. The higher enhancement was found to be 2.1% at high Reynold number value (Re=1000), S/D=5 and nanoparticle concentration ϕ=0.5.
The Relationship Between the Cutting Process Parameters and the Surface Roughness during the Aluminum Machining
Authors: Pop A B , Țîțu M A 
Published: July 2020

Abstract
The purpose of this paper is to identify based on the composite central factorial experiment, the mathematical model between the arithmetic mean deviation of the surface profile and the cutting process parameters (cutting speed, cutting depth and feed per tooth), which describes the studied system in any point of the chosen experimental domain. The coefficients of these equations represent the influence of the variables on the response. The analysis of the variance ANOVA is focused on estimating the different types of variability of the response and the estimations made with the Fisher test. This test analyses the coefficients significance of the regression equation, by comparing the ratio of two variants. The Fisher test indicate the probability to be a statistical difference between them or not. In any case, the experimental results are associated with experimental errors. It is essential to find the prediction accuracy of the coefficient’s values, and not only their absolute value. In the end, will be determined the arithmetic mean deviation of the surface profile Ra, based on the mathematical model, and will be compared with the experimental results.
The Influence of Thermal Factors on the Protection Characteristics of Electro-Insulating Materials
Authors: Buică G , Antonov A E , Beiu C , Dobra R , Risteiu M 
Published: July 2020

Abstract
The use of electrical insulating materials in the manufacture of electrical insulating equipment is the primary prevention and protection measure against electrocution. It must ensure the highest protection of the workers. The study aims to present the results of studies over behaviour of e electrical insulating materials under the influence of the thermal risk factors, to verify the functionality and to ensure the safety function throughout their use. Electrical insulating materials and equipment intended for use as protection mean in low and high voltage electrical installations have been tested. The verifications aimed at identifying the technical and safety parameters of the electrical insulating materials and protective equipment, in case of an event generated by one or more thermal factors or in combination with other professional risk factors, to test and guarantee the applicable technical and safety requirements.
Research Regarding the Influence of TiO2 Nanoparticles on the Performance of Cementitious Materials
Authors: Grebenisan E , Hegyi A , Lăzărescu A 
Published: July 2020

Abstract
Urban buildings are subject to deterioration and degradation due to the action of external factors, air pollutants, water, compounds resulting from fuelcombustion used for heating and transportation, etc. Research on self-cleaning cementitious materials is developing at fast pace and contributes to the high interest in the industry in the decrease of evnironmental pollution, which is of real interest. The aim of this paper is to highlight the influence of the addition of TiO2 nanoparticles on the self-cleaning ability of cementitious materials, under staining with an aqueous solution of a rodamina B, followed by exposures to the action of UV rays, followed by artificial rain cycles and to determine the physico-mechanical properties of the material, as well as the white dregree of the samples and their self-cleaning. Based on experimental research results it can be said that the white degree of the samples increased with the increase of the TiO2 amount in the mixtures. Several other factors such as the intensity of the UV light also affected the self-cleaning capacity of the samples, better results being recorded for higher UVA intensity. The TiO2 amount in the mixtures also influences fresh and hardened state properties of the material such as setting time, apparent density, water absorbtion and porosity of the material. It can therefore be said that it is necessary to identify an optimal range of TiO2 nanopraticles concentration in the cementitious matrix, in order to obtain the maximum cumulative benefits in terms of self-cleaning capacity, physico-mechanical properties and costs.
Novel Trip Steel – Characterization, Impact Test and Comparison with Existing Trip Steels
Authors: Pantilimon M C , Tarcea C I , Gradinaru C S , Coman G , Ciuca S , Sohaciu M , Predescu C 
Published: July 2020

Abstract
4 TRIP steels were produced by use of an induction furnace with controlled atmosphere and vacuum, one of which having a completely new chemical composition with the purpose of obtaining an increased reaction during impact when compared to the other, already documented, steels. This study follows the heat treatment used in order to obtain the TRIP effect in the produced steels and the reaction that the steels exhibit when submitted to an impact test used to simulate a car crash at approximately 60 km/h. The preparation of the samples for both characterization and testing follow standard procedures in terms of analysis. The crash-like tests were performed by using an INSTRON 9340 Ceast which generated an impact energy of 18J. The comparison between the different types of TRIP steels helps to determine the best application of the purposed steel in the automotive industry.
Influence of the Imposed Parameters on XRD Patterns of Electrochemically Top-Down Obtained Nanoporous Al2O3 on Al1050 Alloy
Authors: Basliu V , Benea L , Simionescu N 
Published: July 2020

Abstract
1050 Aluminum alloy samples polished electrochemically in solution of 15% Na2CO3 and 5% Na3PO4 were subjected to the anodic oxidation process in an acid electrolyte, of 1 M H2SO4 to which 1 g / L Al2(SO4)3 × 18 H2O was added for the formation on their active surfaces of aluminum oxide nanoporous layers by top-down nanotechnology method. The applied parameters during the anodic oxidation processes were varied in order to obtain the most uniform aluminum oxide nanoporous layers. Thus the potential was varied between 1 V and 25 V, the duration of the oxidation processes was between 10 minutes and 48 minutes and the stirring rate of the electrolyte was between 0 and 700 rotations per minute. The formation of nanoporous layers of aluminum oxide was observed when the applied potential was between 15 V and 21 V, the duration of the anodic oxidation process was varied between 25 and 45 minutes and the stirring rate of the electrolyte was between 0 and 500 rpm. Too low duration and / or too low potential caused an electrochemical polishing phenomenon to occur and the imposition of too high potential caused dissolution of the alloy substrate. Also, the use of a dynamic electrolyte regime produced a homogenization of the electrolyte temperature during the anodic oxidation processes and the growth of the aluminum oxide nanoporous film is slowed down. XRD diffractogram analysis reveals an enhancement in peak intensity correspondent to aluminum oxide concomitantly with a reduction in peak intensity of metallic aluminum for aluminum nanoporous oxide layers in comparison to the surface of polished Al1050 electrochemically.
Characterization of Zinc and Manganese Phosphate Layers Deposited on the Carbon Steel Surface
Authors: Burduhos-Nergis D P , Cazac A M , Corabieru A , Matcovschi E , Bejinariu C 
Published: July 2020

AbstractThe phosphating process is usually used to improve metals corrosion resistance properties. In this article, the carbon steel surface was coated with a phosphate layer based on zinc or manganese. Three types of phosphating solutions with different substances and concentrations were used for this process. The deposited layers were structurally characterized by Fourier-transform infrared spectroscopy (FTIR) in order to highlight the main compounds specific to the phosphate layers. In the same time, by means of this analysis it is possible to confirm and evaluate the formation of coating layer and its degree of hydration.
The Effects of Solid to Liquid Ratio on Fly Ash Based Lightweight Geopolymer
Authors: Ibrahim W M W , Ahmad R , Coman B T , Abdullah M M A B , Puskas A , Jaganathan V S 
Published: July 2020

Abstract
Geopolymer material was used as the raw material because it promotes the green technology. In this study, lightweight geopolymer was produced using fly ash as raw material with the addition of alkali activation which is mixture of sodium silicate and sodium hydroxide, foaming agent that gives lightweight properties and finally, underwent curing process. The molarity of sodium hydroxide (NaOH) used was fixed at 12 M while the ratio of fly ash to alkali activator (solid to liquid) used were varied in the range of 2.0, 2.5, 3.0 and 3.5, by mass. Besides that, foaming agent (Polyoxyethylene alkyether Sulfate) was added to the geopolymer sample to give the lightweight properties. The samples were cured at 80 °C for 24 hours in the oven for curing process and left at room temperature prior for testing for 14 days. The testing of sample was conducted in this study which includes density test, compression strength test, water absorption test and scanning electron microstructure (SEM) test. The results obtained for optimum solid to liquid ratio is 2.5, by mass with the optimum value of compressive strength density value. The mechanical and physical properties of lightweight geopolymer were based on the ASTM International Standard.
Void Distributions in Sn-3.0Ag-0.5Cu (SAC305) Composite Lead Free Solder Subjected to Thermal Ageing Using Acoustic Micro Imaging Technique
Authors: Zaimi N S M , Salleh M A A M , Abdullah M M A B , Mostapha M , Baltatu M S , Ahmad R 
Published: July 2020

Abstract
The formations of the voids in SAC305 lead free solder and SAC305 with additions of kaolin geopolymer ceramics were studied. The composite solders were fabricated by using powder metallurgy with microwave sintering method. The samples were sandwiched between two copper substrates and reflowed in a reflow oven and aged at 125°C for 0 and 7 days. The acoustic micro imaging was used to analyse the distributions of voids in the solder joints of SAC305 and SAC305 with additions of kaolin geopolymer ceramics. Results shows that, rhe void in SAC305 are larger in size and numbers as compared to SAC305 with additions of kaolin geopolymer ceramics for both reflowed and aged conditions.
Comparison Study on Microstructure Properties of Kaolin Based Geopolymer Ceramics with Addition of UHMWPE under Different Sintering Condition
Authors: Ahmad R , Abdullah M M A B , Ibrahim W M W , Sandu A V , Vizureanu P , Tengah M S 
Published: July 2020

Abstract
To better understand the structure-mechanical properties relation of additively fabrication of kaolin geopolymer ceramics with sintering method, a comparison study was performed. Kaolin based geopolymer ceramics were synthesized starting from the powders of kaolin based geopolymer, using powder metallurgy method. Typically, the sintering method used are one step (1200 °C – 5 min) and novel two step sintering processes (600 °C-5 min and 1200 °C – 5 min) for both kaolin based geopolymer ceramics with and without ultra high molecular weight polyethylene were applied and compared. The outcome revealed that there is no phase changes on the both sintering method pattern and the two step sintering method giving a smooth surface owing to the densification process during the preheat treatment.
Effect of Iron Oxide (Fe2O3) on the Properties of Fly Ash Based Geopolymer
Authors: Zailani W W A , Abdullah M M A , Arshad M F , Burduhos-Nergis D D , Tahir M F M 
Published: July 2020

Abstract
Geopolymer is an attractive construction binder owing to its ability to improve the properties of the concrete and preserves the environment from the high CO2 emission. Geopolymer technology will convert the potential hazardous industrial waste such as fly ash into valuable construction materials. However, there is a need of studying the properties of iron-based geopolymer in order to enhance the fundamental and knowledge of the geopolymer research also development in this study area. Fly ash which contains a significant amount of iron oxide (Fe2O3) was used as a precursor and tested at different curing duration (1, 3, 7, 14 and 28 days). Crystallization of iron oxide (Fe2O3) contained in the fly ash under geopolymerization process will be able to turn waste fly ash into a strong concrete materials, simultaneously creating a waste-to-wealth economy. Furthermore, the formation of fayalite detected from the microstructure characterization is mainly contribute to the strength development of the fly ash after 28 days curing.
Influence of the Stand-off Distance and of the Layers Thickness on the Adhesion and Porosity of the 97MXC Deposits Obtained by Arc Spraying Process
Authors: Haraga R A , Chicet D L , Cimpoiesu N , Toma S L , Bejinariu C 
Published: July 2020

Abstract
In this paper, the surfaces of some weakly alloyed steel specimens were covered, by arc spraying process, with a layer of high alloyed steel: 97MXC, using core wires. The technological parameters, used to spray the high alloy steel, were kept constant except for the spray stand-off distance (SOD) which varied on three levels. The research was performed on deposits with a thickness between 0.2-2.4 mm. The microstructure of the deposits, the chemical composition, the physical properties of the layers were investigated by SEM analyzes, X-ray diffraction, microhardness tests and adhesion tests. The porosity of the deposits was determined by optical microscopy. The adhesion of the layer to the substrate was researched by the tensile test. Studies have shown the fact that SOD significantly influences the adhesion and porosity of the deposits. Thus, the increase of SOD determines the decrease of the adhesion of the layer to the substrate by approximately 21.4%, the increase of the porosity of the deposits by approximately 14.2% and variations up to 5% of the microhardness.
CNC End Milling Process Parameters Optimization on Aluminium Alloy by Using Taguchi and ANOVA Methods
Authors: Țîțu M A , Pop A B 
Published: July 2020

Abstract
This paper is focused on the experimental research which is carried out on the machining of the aluminum alloy. Its main objective is to find the optimum cutting parameters used in the end-milling process. An experimental plan was established based on the L27 orthogonal matrix. The experiments were performed using the recommended values for the cutting parameters by the cutting tools manufacturer on the aluminum machining. The design of experiment methods that were used, are the Taguchi method, the variance analysis and the regression analysis. The controllable factors were the cutting speed, the cutting depth and the feed per tooth. The surface roughness represents the objective function and this was obtained by the studied cutting process. The surface roughness was measured longitudinally and transversely in the cutting direction.
Development of Cement-Based Materials Enriched with Polymeric Coated Reactive Grains as Long-Term Promoter of Matrix Continuous Hydration
Authors: Voinitchi C , Baeră C , Zapciu M , Matei C , Szilagyi H 
Published: July 2020

Abstract
The continuing hydration of unhydrated cement grains was proven to be one of the most important processes for promoting the self-healing effect within cementitious composites, by generating the CSH gels as valuable healing products, not only sealing the microcracks but also being able to provide some mechanical recovery of the material, as well [1]. It was also concluded that the process slows down in time, being strongly connected to concrete age. In order to ensure the continuous hydration potential for the cementitious materials, also as essential self-healing (SH) promoter, the addition of reactive grains is considered. This paper presents preliminary aspects regarding the possibility of polymeric encapsulation of some reactive grains and the feasibility of the concept in terms of matrix compatibility to the addition and also their SH performance under induced, controlled cracking. The considered self-healing addition behaves intelligent as it would react with water only when the cracking occurs, creating gaps in the waterproofing coating. The object of this research is less focused on regaining the mechanical characteristics of concrete, like pre-cracking strength, but mainly on preventing aggressive agents from entering in the concrete mass and aggressing the reinforcement.
Electrochemical Behaviour of Ti-Mo Alloys for Medical Application in Biological Solution
Authors: Bӑlţatu M S , Vizureanu P , Bӑlţatu I , Nergis D D Burduhos , Achitei D C , Perju M C 
Published: July 2020

Abstract
Nowadays, primordial concern represent population health with all materials that are used in medical applications. It were obtained three alloys of titanium with addition of elements like molybdenum, zirconium and tantalum, in a vacuum arc melting furnace (VAR), in argon atmosphere. These alloys were investigated in biological solution, similar with to the human body by electrochemical study method (linear and cyclic polarization). Results revealed that it possesses a good behaviour which does not influence the human body, with future applications in medical field.
New Materials and Processes Developed for Cranioplasty
Authors: Mates I M , Semenescu A , Dumitrescu S I , Vidu R 
Published: July 2020

Abstract
Traumatic brain injury is the leader in the ranking of mortality and invalidity. The surgical repair of a defect of the skull by cranioplasty has been practiced since ancient times, when materials of non-biological origin were used for this purpose. New materials and processes are sought to improve osseintegration of implants. Like any surgical procedure, cranioplasty involves complications that may be related to the surgical technique and/or to the patient’s tolerance to the material used. This work described a biocompatible medical device that include two supported meshes for providing mechanical strength and osseointegration properties of the implant, and a multiplayer porous material in between them that is loaded with the required bioactive antibacterial compound to promote a controlled and sustained release of the pharmaceutical agents at the site of surgical intervention. To increase osseointegration, meshes are designed with an open structure and coated with biocompatible materials such as hydroxyapatite. The composition gradient in the multilayer porous material is attained by loading successive layers of porous material with different amounts of bioactive materials and then stacking them to create a gradient of composition across the porous material.
Experimental Investigation on the Development of Geopolymer Paving Blocks by Using Romanian Local Raw Materials
Authors: Lӑzӑrescu A , Szilagyi H , Baerӑ C , Hegyi A , Meița V 
Published: July 2020

Abstract
For the world economic system cement and concrete are indispensable elements for the construction industry. Demand for concrete, hence for cement, is constantly growing, especially in highly developed countries, which means that alternative binders are urgently required to meet the needs of millions of people, without compromising the CO2 levels of the atmosphere. Although environmental issues are currently not sufficiently convincing to create a sufficiently high demand for the production of geopolymer technology, this is expected to increase with the imposition of rules on carbon dioxide emissions and their effects. Preliminary alkali-activated geopolymer concrete mixtures were developed based on a rigorous trial-and-error process in order to establish the mechanical properties of the geopolymer paving blocks. The aim of this paper is to present results regarding the technology of development and optimisation for the production of geopolymer paving blocks, their mechanical properties and implementation possibilities in accordance with the intended scope of use. The study results indicate that alkali-activated geopolymer paving blocks have excellent mechanical properties, by reference to OPC paving blocks, making them suitable for practical applications.