bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of solution concentration and applied voltage on electrospun polyacrylonitrile fibers
Authors: Bakar Sharifah Shahnaz Syed , Foong Kar Mun , Halif Norzilah Abdul , Yahud Shuhaida 
Published: December 2019

Abstract
Electrospinning is a simple and convenient method for fabrication of polymeric nanofibers from polymeric solution. In this paper, polyacrylonitrile (PAN) fibers are fabricated from different PAN solution concentration and applied voltages by electrospinning process. The fibers were then analyzed with Scanning Electron Microscopy (SEM), X-Ray Diffraction (XRD) and four-point probe to study the effect of PAN solution concentration and applied voltage on electrospun PAN fibers in terms of fiber diameters and morphologies, crystallinity and electrical properties. SEM showed that the electrospun PAN fibers with fiber diameter ranging from 0.5 to 2.7 µm. The diameter of fibers were increased with increasing PAN concentration and voltage applied. The increasing voltage also has increased the bead formation on the fibers. The amorphous structure of electrospun PAN fibers was exhibited by XRD. Electrical conductivity of electrospun PAN fibers were increased with increasing PAN concentration but somehow reduced with increasing voltage of the electrospinning.
Thermal behaviour and microstructural analysis of Sn-0.7Cu alloy and Sn-0.7Cu soldered on electroless nickel/immersion gold
Authors: Teoh Ai Ling , Salleh Mohd Arif Anuar Mohd , Halin Dewi Suriyani Che , Foo Kai Loong , Wahab Juyana A. 
Published: December 2019

Abstract
Lead-free solder has been developing since decades due to the environmental and health harmful of lead solder. To compete with the lead solder, the behaviour and properties of lead-free solder have been continually researched and improved. Sn-0.7Cu is one of the most common solder in application and suitable to be used as a control in research. The thermal behaviour by differential scanning calorimeter (DSC) and microstructure formation with elemental analysis by scanning electron microscope (SEM) of Sn-0.7Cu solder alloy was compared to Sn-0.7Cu soldered on electroless nickel/immersion gold (ENIG) substrate in this study. The result showed that the pasty range of Sn-0.7Cu was lower than Sn-0.7Cu/ENIG while the undercooling was higher. Primary and interfacial (Cu,Ni)6Sn5 were formed in Sn-0.7Cu/ENIG due to the diffusion and dissolution of elements from ENIG substrate. The β-Sn dendrites and eutectic phase of Sn-0.7Cu/ENIG was coarser than Sn-0.7Cu due to the decreasing of undercooling.
Preliminary study of zero charge corrosion protection on steel plate embedded in geopolymer paste
Authors: Razak Siti Aisyah , Zainal Farah Farhana , Shamsudin Shaiful Rizam 
Published: December 2019

Abstract
Steel reinforced concrete usually protected against corrosion by passivation of the steel arising from the high alkalinity of the pore solution within the geopolymer concrete. The ingress of chlorides to the steel or concrete interface or carbonation of the concrete reducing the alkalinity of the pore solution at the steel or concrete interface. This will cause loss of durability in reinforced concrete. The corrosion behavior of steel embedded in geopolymer paste was studied by open circuit potential, Eocp
and potential zero charge method Epzc under 3.5% NaCI solution exposure. The Ecorr
(-660 mV vs SCE) more negative than Epzc
value (-630 mV vs SCE). It shows the steel plate have an excessive negative charges. It is noted that the zero charge corrosion protection (ZCCP) method successfully prevents the steel surface suffering from corrosion. Therefore, it is strongly believed that metal under Epzc is not in contact with H+ and OH− ionic charges due to the absence of electrical charge as well as electrostatic attraction on metal surface.
Physical properties of Sn-3.0Ag-0.5Cu lead-free solder with the additional of SiC particles
Authors: Mahim Zawawi , Salleh Mohd Arif Anuar Mohd , Saud Norainiza , Razak Nurul Razliana Abdul , Yee Khor Chu , Ahmad Romisuhani , Ramli Muhammad Mahyiddin 
Published: December 2019

Abstract
Composite solder has gained researcher’s attention due to its promising improvement in physical and mechanical properties for lead-free solder. To improve the properties of Sn-3.0Ag-0.5Cu (SAC) with the promising lead-free candidate, addition of silicon carbide (SiC) as a reinforcement was used in this study. This study was carried out to identify the effect of SiC particle on microstructure evolution and physical properties of SAC based solder alloys. SAC-SiC composite solder was synthesized by powder metallurgy method (PM), which consists of several processes such as mechanical blending, compaction and sintering. Three different weight percentages of SiC particles; 0.00, 0.50, and 1.00 were mechanically blended with SAC lead-free solder. The results show that the additional of particle SiC was able to refine the microstructure and reduced the size of β-Sn.
A review of geopolymer ceramic as a potential reinforcement material in solder alloys
Authors: Zulkiflii Nur Nadiah ‘Izzati , Abdullah Mohd Mustafa Al-Bakri , Salleh Mohd Arif Anuar Mohd 
Published: December 2019

Abstract
Nowadays, lead-free solder has been currently used in electronic packaging technology as part of soldering material. Since SnPb was detected to produce toxicity and might harm the consumers, the usage of Pb solder has been banned by WEE and RoHS. Therefore, various studies have been developed as alternatives to replace the usage of SnPb. Since lead-free solder might not perform as well as their traditional SnPb, researchers suggested to add some elemental reinforcement particles in matrix alloy. Previously, addition of ceramic reinforcement has been widely known in enhancing the properties of solder-substrate. This paper reviews about the presence studies of ceramic as solder reinforcement, the characteristics of geopolymer ceramic as potential solder reinforcement, and their properties in providing a superior solder joint. In this review, the characterization is divided into two stages; 1) characterization of geopolymers in terms of microstructural and crystallographic; 2) characterization of solder properties in terms of intermetallic layer growth (IMC), wettability, and its mechanical properties
Synthesis of alumina nanoparticles by sol-gel method and their applications in the removal of copper ions (Cu2+) from the solution
Authors: Mohamad Siti Nur Syakirah , Mahmed Norsuria , Halin Dewi Suriyani Che , Razak Kamrosni Abdul , Norizan Mohd Natashah , Mohamad Ili Salwani 
Published: December 2019

Abstract
Two different phases of alumina (Al2O3) nanoparticles (γ-alumina and α-alumina) have successfully been synthesized by using a sol-gel method. During the process a mixture of aluminum nitrate and citric acid (C/N=0.5) was heated at 60°C followed by 80°C until a gel was formed. The amorphous gel structure then was dried and sintered from 600°C to 1200°C. From the X-ray diffraction (XRD) analysis, crystalline structure of γ-alumina started to form at 800°C with average crystallite size of 11.5 nm, followed by the formation of the mixture phase of γ-alumina and α-alumina at 1000°C. The transformation from γ- to α-alumina occured at 1100°C of sintering temperature and above with the average crystallite size of 49 nm. The efficiency of the synthesized alumina nanoparticles as an adsorbents was tested by immersing the powder into the copper ions solution. The percentage of the copper removal was measured by using atomic absorption spectroscopy (AAS). It was found that, the efficiency of the alumina nanoparticles as an adsorbent was not depending on their phases, but might due to the increased of the particle size at higher sintering temperature. The highest percentage of removal 82.1% was obtained when using the alumina sintered at 1200°C.
Effect of Laser Loop on Surface Morphology of Copper Substrate and Wettability of Solder Joint
Authors: Roduan S. Faqihah , Wahab J. A. , Aiman M. H. , Zaifuddin A.Q. , Mohd Salleh M A A , Ishak M. 
Published: December 2019

Abstract
The effect of different laser loop parameter on the geometry of micro-groove pattern on copper substrate and its effect on the wettability was investigated. The micro-grooves pattern was fabricated on the copper surface through laser surface texturing process. 3D measuring laser microscope and contact angle measurement test was conducted to measure the geometry of the micro-grooves pattern and wettability of the solder joint respectively. The results showed that the improvement in laser loop parameter increased the depth of the micro-grooves due to the more exposed time which allows more material ablation. It also showed that the contact angle of textured substrate is smaller than the untextured substrate which results in better wettability.
Effects of ultrasonication process on crystallinity and tear strength of thermoplastic starch/cellulose biocomposites
Authors: Ismail Ibrahim , Osman Azlin Fazlina , Ping Tan Leong 
Published: December 2019

Abstract
The thermoplastic starch (TPS)/cellulose biocomposites were manufactured as green biocomposite films. TPS was produced through plasticization process in which the mixture of starch granule and plasticizers (water and glycerine) went through the stirring and heating process. Cellulose was used as filler and prepared in suspension form through ultrasonication process involving isolation of cellulose in water medium. The ultrasonicated cellulose suspension was added into the TPS matrix to produce TPS/cellulose biocomposites by film casting. The effects of ultrasonication duration (1, 2, 3, 4 and 5 hours) on the crystallinity and tear strength of the TPS/cellulose biocomposite films were investigated. Based on the XRD results, crystallinity of the cellulose and biocomposite were altered by the cellulose ultrasonication process. The tear strength of the TPS biocomposites were greatly enhanced when 5-hours ultrasonicated cellulose was employed as filler. The biocomposites demonstrated 241% higher tear strength than the pure TPS film. This could be related to the transformation of the cellulose into more isolated fiber, with enhanced crystallinity for better reinforcing effect to the TPS matrix.
Coefficient of thermal expansion (CTE) study in metal matrix composite of CuSiC vs AlSiC
Authors: Arif Mohd N , Bukhari Mohabattul Z , Brabazon Dermot , Hashmi M Saleem J 
Published: December 2019

Abstract
Metal matrix composites are widely used as advanced materials for thermal management applications. In view of the demands in higher temperature products application, materials with low coefficient of thermal expansion (CTE) and high thermal conductivity are required. Copper Silicon Carbide (CuSiC) is highly rated as the best materials selected for this application because it has good thermal characteristics especially in CTE, but its density is almost high for high temperature electronic device application. An aluminium silicon carbide (AlSiC) composite, on the other hand, is a new candidate for electronic device application since it has low density and good CTE characteristics. CuSiC and AlSiC composites were fabricated via powder metallurgy method through variety volume fractions such as 5%, 10%, 15% and 20%. In the present study, the comparison of CTE between CuSiC and AlSiC composites with different volume fraction of SiC particles has been carried out. The CTE of CuSiC and AlSiC composites were investigated and their responses between 25°C to 400°C were studied using horizontal dilatometer. Based on the experiment results, the density of CuSiC composites are decrease while the density of AlSiC composites is increase with increasing in SiC particles content. However, the porosity for both composites is increases with increasing in volume fraction of SiC particles. As of CTE, both composites showed decreased with increasing in SiC particles content that dispersed in their matrix. The experimental CTE values for both composites seem to be much lower than theoretical CTE value, which means that there has been excellent bonding between each particle after sintering process. The particles distribution has been observed to understand more on the aspect of SiC particles homogeneity in copper and aluminium matrix.
Characterization of Electrical Current Stress and Indentation Creep of Carbon Nanotubes- reinforced Low Melting Temperature Sn-58Bi Composites
Authors: Sia Kian Lu , Barakbah Syed Alif Ilyasak , How Ho Cheng 
Published: December 2019

Abstract
Sn-58Bi eutectic alloy emerges as one of the potential lead-free solder material candidates due to its low melting temperature that enables low temperature soldering reflow process during the manufacturing of fine-pitch and low z-height advanced microelectronic devices. Its low melting temperature provides feasible solution for a two-step reflow process in the assembly of 3D-stacked advanced packaging technology, and at the same time reduces dynamic warpage-induced quality and reliability issues. However, miniaturization of these microelectronic devices has triggered significant reliability risk to its solder interconnects due to the requirement of high current density that resulted in severe physical failures, such as electromigration (EM), and thermomigration (TM). To mitigate the risk, carbon nanotubes (CNT) are incorporated into elemental Sn and Bi powders using planetary ball milling technique, and subject to liquid phase melting to form low melting temperature CNT- reinforced eutectic Sn-58Bi composites. Electrical resistance and current density of the eutectic alloy and its composites were investigated, and results show that Sn-58Bi-0.03CNT composite has the lowest electrical resistance and was able to survive 26 times longer duration of current stressing, even with the supply of higher stressed current. Creep performance of eutectic Sn-58Bi system was also examined in this study due to its high homologous temperature of 0.72 at room temperature. Marginal improvement in indentation creep performance was seen in the composites.
Territorial aspect of forming united territorial communities
Authors: Hasenko L V , Lytvynenko T P , Hasenko A V , Dariienko V V , Skrynnik I O 
Published: December 2019

Abstract
To ensure the rational use of land resources and manage them in the territory of Ukraine, it was introduced the process of decentralization of power. The article considers the main problems of newly created united territorial communities in the field of land management. In particular, during the study of domestic and foreign experience, as well as the detailed study of Skorokhodivska united territorial community of Chutiv district of Poltava region, the following problems were identified: uncertainty of the boundaries of united territorial communities territories; incomplete use of land outside settlements; lack of revenues to the local budget from the land payments; inability to plan activities due to lack of information on land resources; land pollution; refusal to meet the needs of citizens in land plots; lack of proposals to attract investors and business in united territorial communities; poor state of melioration systems maintenance and illegal use of abandoned forests. The main causes of these problems are analyzed in the article and the ways of their solution are suggested.
Improvement of the quality of the geodesic support for the reconstruction of the roads
Authors: Penkov V O , Skoryk O O , Uzviieva O M , Yu Panchenko V , Korostelov Ye M 
Published: December 2019

Abstract
Further development of the roadway network in Ukraine will basically take place by modernization, which, in fact, conversion of the system « Road Conditions-Traffic Flow-Environment» from one state to another. Generally, it changes not only the spatial axle position of an existing road, but also the geometric and technological parameters of the road. Modern technological design and construction processes demand higher accuracy and reliability in determining the output spatial parameters measured with survey methods and techniques. Therefore, substantiated higher accuracies and improved survey techniques are tasks of primary importance. They must be solved on the basis of determination of rational error limits in survey works and their influence on the accuracy of building, transport operational and economical parameters of the project and actual engineering structures. The objective of the study is to demonstrate possibilities and efficiency in using various models of the system of ensuring the accuracy in survey works for roadway modernization and for solving other tasks on determination of geometric element parameters of complicated sections on existing roadways.
Theoretical basis of quality assessment of railway technical condition
Authors: Shtompel A M , Korostelov Ye M , Batsamut V M , Olenchenko V T , Horielyshev S A 
Published: December 2019

Abstract
The qualitative performance of the track facility in Ukraine depends upon the technical state of rail track structure, which is determined by correspondence of the characteristics to the current Regulations for laying and maintenance the track on railways of Ukraine. And the parameters indicating the rail track stability directly depend on the carrying capacity of the rail base and the stress-strain behavior.
The rail base consists of elements of various physical and mechanical properties, with its own deformation behavior and stressed state under force loading. Therefore, the stress-strain behavior of the rail base must be evaluated with an appropriate mathematic model showing a flow of forces from one element to another.
The rail track structure operates under the power loading from a train. This load considerably influences operation of the rail track structure and conditions the changes in the technical state in operation. In operation the technical state of the rail track structure is getting worse because the residual deformations accumulated in it, which lead to lower train traffic safety. Nowadays requirements for operational safety of the rail track structure are high, and the problem of evaluation of the stress-strain behavior of the rail base is of great importance.
The design of the length of the route transport stops’ landing pad on streets of the city
Authors: Yu Timkina S , Stepanchuk O V , Bieliatynskyi A A 
Published: December 2019

Abstract
An analysis of the condition and problems of stops of route transport functioning was carried out. The research used theoretical and empirical methods, mathematical modeling for creating a mathematical model of the bandwidth of stopping route transport and the final formalization of the scheme of its operation with and without maneuvering. Analyzing the places of congestion on the street network of the city of Kyiv, we came to the conclusion that one of the reasons for their formation had been insufficient organization of road transport and parking of passenger transport precisely at the locations of stops of route transport. Parameters of stops of route transport and intensity of traffic of public passenger transport have a significant influence on the capacity of city streets and roads. Increasing of the number of vehicles on the city streets, improving their specifications have required a new approach to determining the geometric dimensions of mass transit stops. On the basis of the conducted research, the sizes of the recommended calculated passenger vehicle for the design of elements of public transport stops have been proposed. It is established that when designing stops of route transport, it is necessary to consider the length and width of the calculated vehicle, which are important in determining the area of dynamic and static dimensions of vehicles in the area of the stop. An individual approach shall be taken during the designing of the bus stops on city streets that takes into account the dimensions of the passenger vehicle and allows optimizing the parameters of the boarding and boarding places and thereby reducing the time spent on the bus stop.
Strength calculation of risers near the supports of reinforced concrete three-hinged frames based on the concrete plasticity theory
Authors: Dovzhenko O , Pohribnyi V , Klymenko Ye , Oreškovič M , Maliovana O 
Published: December 2019

Abstract
The necessity of estimation of residual strength of risers sections near supports of reinforced concrete three-hinged frames at their reuse after operation in aggressive environment conditions and damages presence is indicated. The method of calculating the elements strength under the shear on the joint action of the transverse and longitudinal forces based on the plasticity theory is elaborated. The variational method, the virtual velocities principle, discontinuous solutions are applied. The kinematically possible failure schemes, the realization of which depends on the values ratio of transverse and longitudinal forces are proposed. The application boundary of these schemes is defined. The permissible level of concrete class reduction and the degree of its integrity violation were established, under which the residual strength of serial three-hinged frames near the supports was provided.
Increasing the accuracy of definition torsional geometric properties for rolled and welded beams
Authors: Hudz S A , Gasii G M , Hasii O V 
Published: December 2019

Abstract
The features of determining the torsional geometric properties of the cross-section of a steel beam, rolled or composed of three sheets of arbitrary thickness, are considered. When calculating warping properties, it is suggested to take into account the degree of torsional stiffness of the attached structures, that more accurately reflects the actual operation of the fixed beam in the composition of the decking. The differentiated account of rounding at the flange adjacent to the web leads in the rolled profiles to a significant structured increase in the value of the torsional constant. These factors characterize the special conditions of operation of the steel element with complex resistance, that allows determining more precisely the value of internal forces, namely the design bending moments in two planes and the bimoment, which are proportional to the distribution function of the angle of rotation of the rod along its length. It is noted that in fact the bimoment is not only determined by on the load, the elastic bending-torsional constant of the cross-section and the span of the beam, an eccentricity, as well as on the stiffness of the structure that attached to the beam.
Decision-making on quality composition materials exposed to temperature differences
Authors: Afonin V V , Erofeeva I V , Kondrashchenko V I , Emelyanov D V , Fedortsov V A 
Published: December 2019

Abstract
An approach is considered that allows one to make a decision on the choice of compositions of composite materials that have been exposed to temperature changes for a long time. The alternatives are considered – compositions of materials and special criteria, the analysis of which underlies the optimal choice of composition from the group under consideration. Proposed the formation of criteria by which the decision is made to assess the quality of building composite materials. In this article, the criteria are formed on the basis of such properties of building materials as hardness and modulus of elasticity on the surface of the test samples, which were subject to negative and positive temperature extremes. Criteria for each property of the sample are formed on the basis of the given values relative to the starting point of exposure. To make a decision about the quality of composite materials, it is proposed to form three criteria for each of the considered properties of materials. The first criterion is calculated as a change in the corresponding property relative to the initial exposure point. The second criterion is determined sequentially with respect to each exposure point by a change in each of the considered properties. The third criterion is represented as the sum of the first two criteria. After that, some provisions of the ELECTRE methods are applied for ranking the studied compositions of composite materials.