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Machining of difficult-to-process materials, including composite materials, is carried out in cost-effective conditions by resorting to abrasive water jet cutting. The quality of the kerf depends on a large number of input parameters, so that their selection becomes a current problem of real technological interest. Thus, the paper analyzes the cut zones defined by the material removal mechanisms, regarding both their extension and the obtained roughness, through the experimental modeling of the Rz parameter.

The paper deals with research on a hybrid technique of coating by Electrical Discharge Deposition (EDD) which has the advantage of lower costs than the other similar methods. This is due to the possibility of using a usual electrical discharge machine, with common tooling, aided by electromagnetic coils that increase the precision and the quality of deposed layers. Some metallic materials like W, Al, Ni, and Ti of high purity are used for EDD, which could be taken from available wires providers. Numerical simulation of the EDD process, using the metals mentioned above was achieved in Comsol Multiphysics. Two connected modules (physics) were used: Magnetic Fields that produced the magnetic force that actuated each of these four categories of ions and Charged Particle Tracing that highlighted the distribution of particles on different cut planes – Poincare maps. Based on these results provided by numerical simulation, it was possible to evaluate the ions behavior, in comparison to electrons, during EDD that is influenced by their atomic mass and the charge number.

Saline soil is an inferior and special material consisting of fine soil particles and possesses poor engineering properties. The swelling, salt heaving, and corrosive behaviors of this soil render it unsuitable for pavement construction due to its deteriorating effects. To use this soil as a subgrade material in the roadway, this soil needs to meet various engineering standard criteria such as deformation, sulfate reduction, strength, and durability for use as subgrade material. Hence, the soil underwent careful stabilization using designed proportions of chemical additives such as lime and slag-based materials. The paper studied the feasibility of using slag-based materials (by-products of the steelmaking process) such as ground granulated blast furnace slag (GGBFS) and basic oxygen furnace slag (BOFS) with lime in stabilizing sulfate-saline soil. On this premise, four designed mixtures, which include saline soil (control), [soil+6% lime], [soil+4% lime+2% (50% GGBFS+50% BOFS)], and [soil+4%lime+2% (70% GGBFS+30% BOFS)] for use to determine their various geotechnical and durability properties. The experimental program for determining these properties included proctor compaction, unconfined compressive strength, three-dimensional (3-D) swelling, and dielectric constant tests. As a result, the laboratory test findings have revealed that adding GGBFS and BOFS to the lime-treated saline soil decreased the maximum dry density, enhanced the strength parameter, and reduced the soil's volumetric swelling and moisture susceptibility.

The paper reported the study on the tensile strength of polymer composite reinforced with abaca fiber and polyester matrix. The effect of fiber weight content and fiber orientation on the tensile strength of the abaca composite were investigated in the study. The abaca composite panel was fabricated using press method with 3 levels of the fiber weight content (20%, 30% and 40%) and 3 levels of fiber orientation (00, 450 and 900). The tensile specimen was prepared according to ASTM D3039 standard. The tensile test was conducted using MTS Landmark servo hydraulic testing machine with a tensile speed of 2 mm/min. The result of the experiment showed that both of fiber weight content and fiber orientation gave significant effect on the tensile strength of the abaca composite. The highest tensile strength was 61.9 MPa, produced by the abaca composite panel with fiber weight content 30% and fiber orientation 00. According to the standard, the tensile strength has fulfilled the requirements as a non-structural material.

Conventional concrete pavement is more efficient towards mechanical load but combing with environmental loads compromises serviceability. This paper mainly focuses on utilizing sintered fly ash (SFA) aggregate to partially replace coarse aggregate in pavement quality concrete. Incorporating SFA aggregate in concrete pavement enhances the thermal behavior of rigid pavement due to higher voids and lower thermal conductivity. Coarse aggregate was partially replaced with SFA aggregate at an interval of 10 % till 40% by volumetric replacement. Pavement quality concrete (PQC) was designed as per Indian standards with a fixed water-cement ratio of 0.36 to achieve a minimum of 40 N/mm2 compressive strength. Compressive, split tensile and flexural strengths were inspected as mechanical behavior and thermal conductivity was examine as thermal behavior of different SFA mixed PQC. It has been observed that there is a slight decrement in mechanical strength by incorporating SFA in PQC but the thermal property of PQC was improved. Overall, it can be concluded that incorporating SFA at a certain level enhances the combined thermo-mechanical properties of PQC.

In this paper, the influence of anti-solvents on the properties of cesium bismuth iodide (CBI – Cs3Bi2I9) perovskite solar cells (PeSCs) that were dripped with different anti-solvents, i.e., isopropanol, chlorobenzene (CB), and toluene during the spin-coating process was evaluated. Scanning electron microscopy images visually depicted the presence of extremely flat and homogeneous film with highly compactness for the Cs3Bi2I9 fabricated with isopropanol compared to other anti-solvents. A strong absorption band was observed at around the wavelength of 500 nm for all the CBI films, and we found that the maximum absorption percentage reached as high as 85%, while the current-voltage measurement showed that the CBI film fabricated with isopropanol showed twenty-one times increment than CB, in terms of power conversion efficiency and short circuit current density. Our findings suggest a further improvement of CBI film morphology by the anti-solvent for enhanced morphology and better solar cell performance in the future.

In this paper we study the feasibility of the design/fabrication of a vertical trench 4H-SiC Junction Field Effect Transistor (JFET), assuming realistic constraints of the depth of the P+ implantation. The P+ doping profile is obtained using a Monte Carlo implantation simulation. The calculation used a drift-diffusion approach. The JFET aims to achieve a threshold voltage of-3V. We found that this constraint in concomitance with the proposed structure limits the breakdown voltage to approximately 200V. This is the result of a premature breakdown induced by short channel effects, namely Drain Induced Barrier Lowering (DIBL). However, a negative increase in the gate bias represses this short channel effect and improves the breakdown voltage to roughly 1800V. At this gate bias, the breakdown is induced by reaching the critical field strength of 4H-SiC at the gate P+/N junction, which causes avalanche generation of carriers. In addition, we have calculated the dependence of the threshold voltage on the drift doping and pillar width. This work also shows the vulnerability of the design to random fluctuation in the doping profile.

Seasonally frozen soil is widely distributed all over the world. The change of the mechanical properties of the soil in the seasonal frozen area under the actions of freezing-thawing cycles are studied in this paper. Research show that pavement rebound deflection and tensile stress in the pavement both increase with the increase of freezing-thawing cycles times, and the overall performance of the subgrade and the pavement decreases under the actions of freezing-thawing cycles. In order to improve the strength and rigidity of the subgrade in seasonal frozen area, geocell is used in the subgrade. Geocell plays a role of "net bag effect" in the subgrade. Despite undergoing the actions of freezing-thawing cycles, when the subgrade is reinforced with geocell, the pavement rebound deflection reduced by 17.3% compared with that in Condition A. The application of geocell improves the bearing capacity of seasonal frozen soil and the stiffness of the subgrade.

This paper describes the development of a sandwich composite beam based on FRP materials which is a suitable alternative to reinforced concrete beams in specific applications. These FRP materials show higher durability and stability compared to reinforced concrete in aggressive environments (e.g. wastewater treatment plants). Compared to pultruded FRP beams, the developed solution better utilizes the properties of the sub-components. The results of this research suggest that the optimum use of composite materials is when the upper and lower flanges of the beam consist of pultruded composite profiles in the TT cross-section and the standing composite grating; this creates a relatively stiff beam with a high load-bearing capacity and resistance to aggressive environments at a very low self-weight. The final properties of this beam can be adjusted thanks to the variability of the dimensions of the web as well as the variability of a suitable laminate surface treatment. This in the final combination creates a sandwich composite structure. The behaviour of the composite beam is then confirmed in this paper using a four-point bending test. Different configurations of the beam design allowed us to determine the influence of the laminate surface layer (verification of the sandwich functionality), but also the influence of the beam connection at the standing point on the resulting behaviour. The results of the experiments demonstrated the optimal physical and mechanical parameters of the sandwich composite beam structure and gave us insights for further use of this type of structure.

Concrete carbonation serves as one common durability issues in reinforced concrete structures at present. In order to understand the carbonation mechanism, many methods were developed by previous researchers for the characterization of concrete carbonation. For example, Phenolphthalein spraying method, Thermo-gravimetric analysis (TGA), X-ray diffraction, Fourier Transform Infrared Spectroscopy (FTIR), Mercury intrusion porosimetry (MIP), etc.. In this paper, all existed carbonation methods were summarized, and, based on the parameter (pH value inside pores, microstructure, chemical composition, etc. ) each method focuses, the function behind method was elaborated. Finally, this paper discussed the pros and cons of current methods, and further developing directions were proposed.

The purpose of this paper is to investigate factors associated with press-forming of Wood Plastic Composite (WPC) products. The WPC material is a novel, feasible, and economic way to use recycled thermoplastics. Due to the complexity of the fiber-polymer interaction, numerical simulation and thus prediction of WPC behavior in forming have been challenging. Up to now, press moulds have had to be empirically validated. In this paper, we explore the possibility of predicting material behavior using Autodesk Moldflow.

Thin profile wires made of stainless steels are widely used for production of industrial screens used for filtration and separation processes. Industrial screens made of resistance spot welded thin profile wires are used e.g. in baskets for centrifuges or filtration screens and find a wide range of applications in various branches of the industry (mining, food and sugar industry, paper industry, wastewater treatment, oil and gas and many more). Regardless of the application, increased durability and surface quality of the screens is of paramount importance. Improvement of the longevity of manufactured items, process efficiency and environmental performance can be achieved only when interactions between initial wire rod quality and its susceptibility to metal forming operations are fully understood. Due to the complexity of the manufacturing process of industrial screens (precise and small gaps, narrow ranges of dimensional tolerances), forming of thin, so-called precision profiled wire is difficult. The influence of the charge, i.e. wire rod, parameters of the wire drawing / rolling process play a key role in obtaining semi-finished products characterized by high strength, low surface roughness and a low level of residual stresses. The paper discusses the influence of the initial state of wire rod and deformation parameters on the quality of thin austenitic and lean duplex steel profile wires as well as the possibility of replacing austenitic wires by lean duplex wires and their possible benefits.

The ongoing digitization of production processes provides new possibilities and potentials for process monitoring of forming and stamping processes. The component quality achievable by these processes is strongly dependent on the properties of the sheet metal material, so that a permanent digital recording of material data offers high potential for monitoring each component produced. In this context, presented paper deals with a novel AI-based method for the direct determination of ma-terial parameters from measured punching force curves. Using software systems Python and Tensor-Flow, an artificial neural network was first set up to determine mechanical material parameters (out-put data) from punching force curves (input data). As data basis for the adopted neural network, force curves were measured during punching of various sheet metal materials using a punching tool equipped with a direct force measurement device. Punching force curves were experimentally deter-mined for the sheet metal materials DP1200, DP1000, DP800, DP600, HX380LA, DC03 and DX54. Additionally, tensile tests were performed for these sheet metal materials to determine ultimate tensile strengths (Rm), yield strengths (Rp0.2, Re), uniform strains (Ag), elongations at break (At) and strain hardening exponents (n). The presented paper reveals that neural networks can accurately quantify the relationship between characteristic parameters of punching force curves and the mentioned me-chanical material properties.

To fully exploit the predictive accuracy of advanced anisotropic yield functions, a large number of classical mechanical tests is required for calibration purposes. The Finite Element Model Updating (FEMU) technique enables to simultaneously extract multiple anisotropic parameters when fed with heterogeneous strain fields obtained from a single information-rich experiment. This inverse approach has the potential to mitigate the experimental calibration effort by resorting to a single, yet more complex experiment augmented with Digital Image Correlation. In this paper, we inversely identify the sought anisotropic parameters of two selected yield functions for a low carbon steel sheet based on the previously designed information-rich tensile specimen. The experimentally acquired strain field data is used to inversely identify the Hill48 yield criterion and the Yld2000-2d yield function, respectively. The results are compared with conventional calibration methods for both anisotropic yield functions. The inverse identification is then thoroughly studied using virtual experiments enabling to disentangle the effect of the material model error and the strain reconstruction error (DIC), respectively. It is shown that the material model error dominates the inverse identification of the Hill48 yield criterion. The reduced material model error for the Yld2000-2d yield function enables obtain inversely identified anisotropic parameters that are closer to the reference parameters. The paper clearly shows the importance of the predictive accuracy of the selected anisotropic yield function when applying inverse identification. Keywords: Anisotropic yield criteria; Material parameters identification; Heterogeneous mechanical tests; Inverse identification; DIC.

Even though dates are produced in large scales in Saudi Arabia, it is not the only product palm trees can offer. Transformative products of palm trees that can be beneficial for the community are intense. For instance, using fronds waste as a biomass to generate power at remote areas or central cities where palm trees population is intense might be a transformative product of palm trees. Using natural waste as a supplement source of electricity at the communities living near palm farms will have a profound effect on the environment and economy. This paper discusses the feasibility of using palm trees' fronds as a biomass in Saudi Arabia. It complies with the kingdom's strategic power plan where alternative power sources are encouraged in the vision 2030. This paper briefly illustrates the opportunity of using biomass, statistics of palm trees in Saudi and the use of biomass as a feedstock to generate electricity in Medina region as a case study.

Price and time are two major concerns in the industry which encourages the development and manufacturing of new dies for sheet metal forming applications. Additive manufacturing (AM) and rapid tooling (RT) are now emerging techniques for producing cost-effective and fast production of sheet metal forming dies with excellent mechanical and wear resistance properties. The paper gives an insight into AM processes that were implemented in the tooling industry to enhance moulding efficiency and sheet metal forming processes. The advantages and challenges observed in using AM are highlighted and discussed as opposed to traditional tooling. The RT processes used in moulding and sheet metal formation are addressed, and their limitations are highlighted. The paper also discusses several possible application areas in which AM technologies can be used further to enhance the efficiency of the devices. Finally, discussion on current issues related to the use of AM in tooling has been presented.

Since its first appearance in 1995, metal-organic framework materials (MOFs) have become a research hotspot in the field of environmental treatment due to its advantages of large specific surface area, high porosity and adjustable pore size, especially in the treatment of dye wastewater and heavy metal wastewater. With the deepening of research, as a kind of crystalline material with porous structure, MOFs have a wide application prospect in the field of air purification materials due to their strong adsorption function. This paper summarizes the types and synthesis methods of MOFs, and reviews the application research progress of MOFs in gas separation, gas storage and particulate matter purification. At present, MOFs still have some problems, such as poor stability, low recycling efficiency, high cost and weak functionalization, etc. In the end of this paper, some research suggestions are put forward to solve these problems.

The thermal management processes for PhotoVoltaic (PV) cooling applications, increase PV systems’ overall efficiency and yield to a maximized power generation. Accordingly, this paper investigates recent PV thermal management methods, which involve the use of Phase Change Material (PCM) under the back of PV modules. Compared to other cooling methods (such as air and water based methods) PCM based techniques show less need for maintenance, are environment-friendly, and have a longer life cycle. Since PCM are diverse in nature, and many methods exist to guide their selection procedure, this paper begins by revealing different types of PCM, which are found to be as Organic, Inorganic, Eutectic and Commercial PCM, with the characteristics of each. After acknowledging different PCM natures, a selection process is established based on either the melting temperature, latent heat, or thermal conductivity of PCM. Results have shown that Commercial PCM are the best option followed by Organic PCM, due to their improved chemical aspects when compared with Inorganic and Eutectic PCM. Concerning PCM selection criteria, the easiest yet sufficient process is based on the melting temperature method, due to the simplified calculations when compared to other thermic quantities. At the end, future work recommendations are declared, related to PCM lifecycle assessment and cooling/heating cycles effects on PV entropy.

The paper refers to the results of an experimental investigation on partially FRCM confined clay brick masonry. Seven small-scale masonry columns (square cross-section 250x250 mm, overall height 770 mm) were tested under monotonic centred load until collapse. The confining system (basalt-FRCM, SRG) and the number of the confining layers (i.e., 1, 2, and 3) were the varied parameters. Failure modes, load-displacements curves (both axial and transversal) and peak loads were reported and discussed in the paper. The performed research aims to contribute to the knowledge in the field of FRCM/SRG-confinement, mainly focusing on the influence of some of the mentioned parameters. The obtained results could be considered for the validation or the improvement of analytical design-oriented formulas.

This paper discusses the experimental qualification process of Fabric Reinforced Cementitious Matrix (FRCM) composites with Polyparaphenylene BenzobisOxazole (PBO) textiles. FRCMs consist of fiber textiles incorporated within inorganic cement or lime mortar matrices and have emerged as composite materials suitable for the retrofit of unreinforced masonry structures. The Italian Ministry of Infrastructures and Transportation and the European Organization for Technical Assessment have developed guidelines defining standard tests to certify the FRCM mechanical properties for qualification and acceptance purposes. This paper presents part of the experimental qualification results for PBO-FRCM composites with two PBO textiles (unidirectional and bidirectional) applied to two different masonry substrates (clay bricks and tuff blocks), considering tensile, bond and durability behavior. Direct tension tests were carried out on PBO textiles and FRCM specimens, with or without textile lap splices. Single-lap tests allowed determining the bond properties of both FRCMs on clay-brick and tuff-block masonry substrates. The stability of the tensile properties with respect to degradation induced by environmental actions was evaluated by performing direct tensile tests also on FRCM specimens conditioned in humid, saline, and alkaline environments, or subjected to high-temperature stress.

An experimental investigation aimed to analyze the mechanical behaviour of Carbon Fiber Reinforced Composite (CFRP) anchor spikes inserted in a brick substrate is reported in this paper. As is well known, such devices can improve the structural performance of CFRP sheets externally bonded to masonry elements (as well as others substrate materials). In structural applications, spike anchors can be subjected to both shear and/or normal actions; the first commonly occurs in structural applications, while the latter may occur in specific applications, such as CFRP sheets bonded to curved surfaces. For this reason, the experimental program described in this paper analyzes the mechanical behavior of a typology of anchor spikes loaded (separately) by pure shear or normal actions. Although, obviously, in anchored CFRP sheet reinforcements the contribution to the bearing capacity of the sheet and of the anchors cannot be additively superimposed (the total capacity is of course not equal to the sum of the capacity of the sheet and of the anchor), the results described in this paper can still give useful indications in practical applications.

Additive Manufacturing is an emerging technology used in wide applications including, wastewater treatment. This paper presents applied techniques of Additive Manufacturing in producing a 3D-printed prototype model of a laboratory-scale wastewater treatment process. This paper aims to show the efficiency of bioremediation of freshwater algae in reducing traces of phosphate and nitrates - both known pollutants responsible for eutrophication. The study also comparatively reviews two different set-ups: stagnant and aerated. 3D printed bio-propeller, a polylactic acid-based aerator, was applied to the latter aforementioned set-up and was designed to be durable, environmental oriented, and cost-efficient. Moreover, the features and details of the 3D-printed bio-propeller emphasized its ability to promote algae harvesting by acting as a sustainable biofilm for algal growth. It is found that both set-ups show significant algae bioremediation efficiency for the synthetic nutrients. Also, the aerated set-up indicated a favorable result with the highest efficiency of 92.857% for nitrates and 41.667% for phosphate. It is concluded that the potentials of 3D printed bio-propeller as a prime component of Rotating Biological Contractor (RBC) can promote sustainable wastewater treatment.

Renewable energy contributes to the building sector's current global transition towards a sustainable energy system. Several renewable energy sources and solar photovoltaic have sparked great interest in reducing the dependency on fossil fuels and greenhouse gas emissions and mitigating global warming by harnessing the sun to power the energy. However, the exploitation of solar photovoltaic in an existing building requires various considerations with high uncertainty from the building owner. Thus, this study focuses on investigating determinant factors and their influence on the decision of solar photovoltaic implementation to ensure its success and efficiency. For this purpose, an extensive literature review conducted for the establishment of criteria. Then, a questionnaire survey was designed; and with the help of various stakeholders, consists of green building certified professionals to support the process in choosing the determinant factors. The outcome of the analysis from Exploratory Analysis of Principal Component Analysis with Varimax Rotation reveals that solar photovoltaic implementation is affected by economic, management, environmental, and technical factors. Optimizing the factors discussed in this paper provides insight into adopting renewable sources effectively. This paper also contributed to building knowledge to facilitate more research on factors in implementing solar photovoltaic projects in the future.

In this paper, the impact of the anode contact in SBDs, PiN, JBS and MPS diodes is analyzed through TCAD simulations. The focus of the investigation is the correct simulation of the Schottky barrier height on the different areas of the device to correctly simulate a JBS or MPS structure. It is found that the splitting of the anode contact and an accurate selection of the Schottky barrier height on pzone is necessary to allow the onset of the bipolar conduction in MPS devices. In this way, it is possible to correctly analyze the behavior of an MPS diode, including the snapback phenomenon.

SiC power MOSFETs have made great progress since the first commercial devices were introduced in 2011, but they are still far from their theoretical limits of performance. At blocking voltages above 1200 V the specific on-resistance is limited by the drift region, but below 1200 V the resistance is dominated by the channel and the substrate, with smaller contributions from the source and JFET regions. Trench MOSFETs have smaller cell area than planar DMOSFETs, and are inherently more scalable. Both Rohm and Infineon devices have cell pitches of about 3 μm per active channel. In this paper we demonstrate a highly self-aligned fabrication process to realize deeply-scaled trench MOSFETs with a cell pitch of 0.5 μm per channel. Since the narrow gate trench is shaped like a letter “I”, we refer to these devices as “IMOSFETs”.

10kV+ rated 4H- Silicon Carbide (SiC) Insulated Gate Bipolar Transistors (IGBTs) have the potential to become the devices of choice in future Medium Voltage (MV) and High Voltage (HV) power converters. However, one significant performance concern of SiC IGBTs is the extremely fast collector voltage rise (dV/dt) observed during inductive turn-off. Studies on the physical mechanisms of high dV/dt in 4H-SiC IGBTs revealed the importance of collector-side design in controlling the phenomenon. In this paper we propose a novel collector-side design approach, which consists of four n-type layers with optimized doping densities and allows the control of dV/dt independently from the device performance. Further, we demonstrate a reduction of dV/dt by 87% without degrading the high switching frequency capability of the device, or the on-state performance, through the addition of two n-type epitaxial layers in the collector side, between the buffer and the drift regions.

In this paper, Shockley-Read-Hall (SRH) lifetime depth profiles in the drift layer of 10 kV SiC PiN diodes are calculated after MeV proton implantation. It is assumed that the carbon vacancy will be the domination trap for charge carrier recombination and the SRH lifetime is calculated with defect parameters from the literature and proton-induced defect distributions deduced from SRIM calculations. The lifetime profiles are imported to Sentaurus TCAD and static and dynamic simulations using tailored lifetime profiles are carried out to study the electrical effect of proton implantation parameters. The results are compared to measurements, specializing on optimization of the trade off between on-state and turn-off losses, represented by the forward voltage drop, VT, and reverse recovery charge, Qrr, respectively. Both the simulated and measured IV characteristics show that increasing proton dose, or energy, has the effect on increasing forward voltage drop and on-state losses, while simultaneously, the localized SRH lifetime drop decreases the plasma level, increases the speed of recombination and decreases reverse recovery charge. Finally, TCAD simulations with different combinations of proton energies and fluences are used to optimize the trade-off between static and dynamic performances. Reverse recovery charge and forward voltage drops of these groups of diodes are plotted together, showing that a medium energy which induces the most defects in the depletion region relatively close to the anode gives the best dynamic performances, with a minimum cost of static performance.

Conventional finite element (FE) modelling, which employed structured mesh, is unable to simulate local damage evolution at microstructure level. This paper aims to investigate the creep rupture and damage behaviour of Grade 92 steel under a creep environment using microstructural-type FE mesh. The idealised microstructures of the material were generated based on the Voronoi tessellation technique. Three notched bar specimens with different notch acuities were modelled in Abaqus v6.13 software and a ductility exhaustion based damage model was employed to estimate the damage state. The influence of the notch constraint on the ductility is accounted for in the simulation. It is found that the results obtained from the proposed technique are in good agreement with the experimental data. All the prediction points fall within the scatter band of +/- factor of 2. The damage was predicted to initiate at a distance offset from the notch tip. As the acuity increases, the damage initiation site shifts further away from the notch.

Single point incremental forming process, which is also known as SPIF, that forms from one direction. SPIF process was used for milling an aluminum metallic sheet. In this paper, an aluminum (A5052) sheet was formed in a conical shape by the SPIF process. The A5052 sheet was deformed by the computer numerical control (CNC) technology in the T60 series milling machine. The conical shape was deformed by the spiral toolpath in the T60 series milling machine. At the surface of the A5052, lubricant grease was continuously applied manually for reducing the friction generated due to milling. Also, for decreasing the tool rotational force friction on the A5052 sheet there was the use of lubricant. Moreover, 0.1mm step-down is used for the tool path because it takes more time for forming a metallic sheet, however, it deformed the sheet smoothly. The 0.5mm step-down g-code was extracted from fusion 360. Then the metallic sheet A5052 surface was compared before and after deformation. For testing a metallic sheet A5052 the formability parameter was analyzed in the experiment part. The experiment was performed to find the optimal smooth surface from the CNC milling machine. The initial roughness value and the microscopic image were presented in the investigational part. Likewise, the comparison of points for the highest and lowest rough point was further discussed and compared throughout the experiment.

Three-dimensional finite element modeling (FEM) has been carried out using QForm software on the hot forging operation of the upper ball joint, involving the process of roughing and finishing. The material used is SNCM8 commercial alloy steel. This paper aims to optimize the initial billet size to achieve a final forged product without any defects. To accomplish this task, it was necessary to determine the initial optimum billet size by calculating the mass ratio. It is more practical to reduce the length of the initial billet and keep the diameter constant. The initial billet size was obtained by FE simulation by varying the five cases of mass ratio. The minimum dimension of the initial billet, which filled the die cavity without defects, was selected for the tryout experiments. The experimental results supported the FEM results and indicated that the optimum size was ∅48x152.88 mm, which may reduce material waste by 17.65%. Additionally, the forging load during the forging process was investigated. The actual forging load was slightly higher than the experimental one. The forging load showed a maximum error about 10.13%. Finite element simulation by QForm V10.1.6. software is recommended as an efficient tool for predicting the hot deformation behavior of the material during several stages of hot forging, which can save material costs and the cost of trials, leading to enhancements in the manufacturing process.

In this paper, the modeling of SJ-MOSFETs beyond the voltage class of 3.3 kV simulated with verified deep aluminum box-like shaped profiles by using TCAD simulation is described. The simulation results are used to investigate the influence of ion implantation parameters on electrical characteristics. For the formation of pillar regions, high energy implantation is performed through energy filter with a multi epitaxial growth method using a patterned mask. While high thickness of epitaxial layer is indispensable for obtaining a high blocking capability, it is revealed that the optimization of doping concentration of p-pillar and drift layer parameters yields similar on-state-resistance by charge compensations of SJ-structure.

This paper investigates the short channel effects (SCE) of the recently proposed Singular Point Source MOS (S-MOS) SiC MOSFET. The study was carried out using 2D and 3D TCAD simulations for a planar, trench and S-MOS 1200V SiC MOSFETs for the IV output characteristics up to 1200V and under short circuit transient conditions. The S-MOS device shows no SCE up to the rated voltage when compared to reference planar and trench devices which exhibit strong SCE. This is due to the appropriate P++ protection of the N++ source and the electric field shielding due to the narrow mesa dimensions between orthogonal trenches where the channel is located.

This paper evaluates the properties of fly ash (FA) and ground granulated blast furnace slag (GGBFS) based geopolymer mortar mixtures with waste glass sand (WGS) obtained by crushing glass bottles. A total of seven mixtures, including the partial substitution of river sand (RS) with WGS (0%, 15%, 30%, and 45%) with two alkali activator solution to binder (AAS/b) ratio groups (0.4 and 0.3), were designed. Sodium silicate (Na2SiO3) and sodium hydroxide (NaOH) were used as the alkali activators. The experimental program evaluated compressive strength, hardened density, alkali-silica reaction (ASR), drying shrinkage, and thermal conductivity of geopolymer mortar mixtures. Test results indicated that the compressive strength of the geopolymer mortar increased with the addition of WGS for AAS/b = 0.4, but it had a negative effect for AAS/b = 0.3. The FA and GGBFS-based geopolymer mortar helps to reduce the ASR expansion of the mixture containing WGS. The drying shrinkage of the geopolymer mortar decreases with the increase of the WGS content. The increase of WGS decreases the thermal conductivity of geopolymer mortar in the case of mixtures with AAS/b = 0.4, but interestingly thermal conductivity value increases in the case of mixtures with AAS/b = 0.3. The findings of this study suggest that using WGS as partial RS substitution material in geopolymer mortar offers sufficient mechanical and thermal insulation properties without causing durability issues.

The paper presents a model and an algorithm for calculating the operational properties of a metal and a structure after its assembly-welding. The model is based on the equations of non-stationary thermal conductivity and mechanical equilibrium, as well as the analysis of structural-phase transformations using thermokinetic diagrams. It is implemented in the original BAZIS software package. Validation of software was carried out when calculating thermal fields and deformations as applied to arc welding, arc deposition, and laser welding of standard joints.

Heating and cooling activities of buildings consume a considerable amount of energy used in building envelopes and are responsible for almost 16 % of CO2 emissions in the air. This problem has been confronted with a recent worldwide trend by introducing eco-friendly buildings with net zero emissions. Currently used thermal insulators in building envelopes are usually made from synthetic polymers which are difficult to recycle or dispose of. This paper presents a novel bio-composite mats using Egyptian pulled wool fiber waste and flax fibers waste as an alternative to commercial polystyrene foam. High loft nonwoven mats with different blends of wool and flax are fabricated and characterized to utilize a composite structure with satisfactory thermal and physical properties. Thermal conductivity test, ignition test, and compression and recovery test are applied to the developed specimens. The results proved the competitiveness and suitability of the proposed composites to be used as building interior insulators when compared to polystyrene and other similar composite materials from literature.

This paper presents a Computational Fluid Dynamics (CFD) model for friction spot stir welding applied to two plates made of AA5056 alloy. Welding was carried out at several speeds of rotation of the tool, while the temperature was observed from the surface of the upper plate using thermocouple. Using this temperature, the mathematical model was adjusted. Since the model is based on the CFD method, in this case the plate material was specified as a very viscous fluid, the dynamic viscosity of which depends on temperature and strain rates. Welding was carried out at several speeds of rotation of the tool, with its own model created for each speed. As a result, the temperature and dynamic viscosity distributions in the welding zone were obtained.

The paper investigates the optical and photocatalytic properties of strontium bismuthate doped with various rare earth elements. The data presented indicate that the type and concentration of the dopant have different effects on such parameters of a given semiconductor photocatalyst, such as the optical bandgap, absorption in the intrinsic area, and photocatalytic activity. On the basis of the studies carried out, the most promising rare earth elements have been identified and their optimal concentrations have been established for doping alkaline earth metal bismuthates.

The paper proposes and justifies criteria for assessing the propensity of a metal to corrosion cracking in an environment with gas saturation with hydrogen sulfide and carbon dioxide when the loading speed and test temperature change. Various mechanisms of corrosion destruction of several groups of metals used in the oil and gas industry are analyzed.

Palm fuel ash (POFA) and rice husk ash (RHA) are usually disposed to open areas and landfills without treatment, resulting in environmental problems. Both materials fulfilled the criteria as pozzolanic material, thus can be used as substitutes to cement. This paper presents the comparison in the fresh and hardened properties between self-compacting concrete (SCC) containing POFA and RHA. The SCC mixtures were produced based on water/binder ratio of 0.6. Both POFA and RHA were introduced in concrete replacing 0%, 10%, 20% and 30% of cement by weight. The fresh SCC was tested for three (3) fresh properties including filling ability, passing ability and segregation resistance. Meanwhile, the hardened properties of concrete were tested for its compressive strength. The fresh properties of SCC incorporating POFA and RHA fulfilled all the requirements of SCC which include the filling ability, passing ability and segregation resistance. Meanwhile, SCC containing RHA had higher compressive strength than the SCC containing POFA for all different replacement level. This is because RHA had higher SiO2 content than POFA, thus promote more pozzolanic reaction to improve the strength of concrete. Furthermore, the optimum replacement level of POFA and RHA in SCC are 10% and 20%, respectively. However, the compressive strength of both SCC containing POFA and RHA were still lower than the control SCC. It is suggested that the SCC containing POFA and RHA to be cured for longer period to achieve better or equivalent strength to the control SCC.

This paper investigates the stress-strain relationship of a rectangular cross-section concrete element reinforced with Carbon fiber Sheet (CFS). In order to verify the confinement effect of the carbon fiber sheet over the concrete, an experiment was conducted using concrete elements with CFS by changing the ratio of side length of the cross section, the ratio of the height to the short side and the amount of CFS layers. In total, 16 concrete specimens were tested under compressive monotonic loading. In the experiment, the compressive strength decreases, and the ultimate strain increases as the ratio of side length increases. Furthermore, we proposed an evaluation formula for a rectangular cross-section concrete element reinforced with CFS. The proposed formula corresponds well to the experimental results.

The hydrocolloid impression material is one of the most important materials extensively used in several procedures in the dental field. It is mainly applied for diagnostic and planning in the rehabilitation of oral, orthodontic, and maxillofacial prostheses due to its biocompatibility with the oral tissues, low toxicity, ease of use, and relatively low cost. When doing the impression, the material might be contaminated with blood, saliva, and biofilm from within the patient’s mouth. In these procedures, there are high chance that the microorganisms can be transmitted from patients to the casting materials and then to the dentists or to the dental lab technicians. Several types of disinfectants have been introduced for use to disinfect dental impressions. This study aims to investigate the antimicrobial potential of vanillin-incorporated irreversible hydrocolloid impression material on Staphylococcus aureus, Klebsiella pneumoniae, Escherichia coli, and Candida albicans. The hydrocolloid impression material used in this study is Alginate, Kromopan class A type I, Lascod, Italy. Different concentrations of vanillin (0.1%, 0.5%, and 1% w/w) were added to the impression powder, and the impression samples were made by mixing the alginate powder with water and pouring them on sterile plastic plates. Staphylococcus aureus ATCC 5638, Klebsiella pneumoniae (clinical isolate), Escherichia coli ATCC 11775, and Candida albicans ATCC 10231 were prepared to 105 CFU/ml suspensions in sterile normal saline solution. A total of 100 μL of each microbial suspension was evenly spread onto the surface of the impression and left for 1 min. Then, a 2 x 2 cm2 sterile Whatman filter paper was placed on the impression sample surface to make an imprint and transferred to the Brain Heart Infusion (BHI) agar plate. The number of colonies growing on the BHI agar was counted after incubation at 37°C for 24-48 h. Impression material without vanillin was used as a control. It was found that adding vanillin to the materials could significantly inhibit all tested microorganisms, and the inhibitory efficiency ranged from 12% to 98%. K. pneumoniae showed the most resistance since the inhibitory effect started at 0.5% w/w vanillin and the maximum suppression was 84% at 1% w/w vanillin. On the other hand, S. aureus appeared to be the most sensitive species, as the suppressive response started at 0.1% w/w vanillin and the percentage of inhibition was as high as 98% at 1% w/w vanillin. In conclusion, we combined different concentrations of vanillin (0.1%, 0.5%, and 1% w/w) into the impression material and it showed a significant antimicrobial potential against all tested oral bacteria and yeasts (S. aureus, K. pneumoniae, E. coli, and C. albicans). The suppressive effects were dose-dependent and ranged from 12% to 98%. This did not only disinfect the impression material from the inside but also disinfected the impression from the time it was inserted into the patient’s mouth. Using this hydrocolloid impression material incorporated with vanillin could be beneficial to eliminate cross-infection for dental personnel. Nonetheless, further studies are necessary to investigate some physical properties of this impression material, such as setting time, tensile strength, elastic recovery, and detailed reproduction.

Cold-formed steel members have been widely used in structural applications and have been included in current design standards. These current standards have been established on the basis of the idealized plastic behavior of material properties, whereas the rounded stress-strain curves are obtained with the significant strain hardening due to cold-forming processes. The predictions from the current standards become overly conservative compared to the actual strengths of cold-formed steel sections. A new design method named the Continuous Strength Method, therefore, has been proposed and developed to provide more accurate strength predictions of this structural type with the consideration of strain hardening effects. In this paper, this method is applied to investigate the sectional capacities of cold-formed rectangular hollow steel sections under compression or bending with the variation of ultimate strengths compared to the predicted strengths using the European Code.

Cold-rolled aluminium sections can be seen as the new products and are manufactured by using the existing rolling system for cold-formed steel sections. These new sections have illustrated their advantages in comparison with the extruded aluminium sections. The buckling behaviors of cold-rolled aluminium sections are different from those of the extruded ones; and their behaviors have been illustrated to be significant impacts by geometric imperfections due to unavoidable reasons in manufacturing, transportation and assembly. The paper, therefore, investigates the sectional buckling behaviors of cold-rolled aluminium alloy channel columns with the consideration of the geometric imperfections in the analysis. The imperfection amplitudes used for the investigation are randomly selected based on the collected data from previous research studies. The investigated results are the base for the analysis of sectional buckling behaviors of cold-rolled aluminium alloy channel columns, and for the determination of detrimental strengths that can be used for further studies.

In this paper, the effect of direct and pulsed current in the arc welding with the use of UONI 13/Moroz coated electrodes on the structure and properties of 10KhSND structural low-alloy steel joints was investigated. Welding was performed in winter at an ambient temperature of-40oС. This work is a continuation of the cycle of research on welding of structural steels, carried out by the authors for several years.

Cold-rolled aluminum sections are new products that are available in the market with two typical sections of channel and Zed sections. These sections in the form of thin-walled sections become sensitive to buckling instabilities, leading to different behaviors in comparison with those of traditional extruded aluminum sections. The current aluminum design standards were regulated on the basis of research studies on extruded aluminum sections, and their accuracies in the design of cold-rolled aluminum members have been not reported. Based on collected experimental and numerical strengths of cold-rolled aluminum channel columns, the paper will compare these collected data with the strengths predicted by American Aluminum Specification. The comparisons are the bases to provide recommendations for the application of American Aluminum Specification in the design of cold-rolled aluminum channel columns. This specification was found to give conservative predictions for global buckling failure modes and provide un-conservative predictions for local-global interaction buckling failure modes in the design of aluminum alloy channel columns.

The present paper aims to highlight the first findings of the GIVILIF project (Group Induced Vibrations on LIght Floors). The primary purpose of this project is to improve the existing standards around the vibrations of timber floors induced by group activities. It presents the first part of the applied methodology for the subjective and objective evaluation of vibrations. First, a survey among inhabitants was conducted better to understand the vibrational discomfort of existing buildings’ occupants. Then, tests on a shaking table explored the perception of individuals to define thresholds of perception, discomfort and intolerance. It was found that the acceleration graph assures certain conformity with the thresholds offered by the ISO2631 standard concerning offices and residences, purpose of this study.

The paper investigates the effect of ultrasonic impact treatment on the structure and microhardness of constructional steel 10G2FBYu (GOST). Ultrasonic impact treatment of these steel was carried out an air temperature of -30 °C.

The pressing and sintering processes of copper powders produced by different methods are studied in the paper. The main research is based on PMS-1 powders, obtained by electrolysis. To find the easiest and the most reasonable sintering mode, the process is carried out in the open air and dissociated ammonia atmosphere. The samples parameters after each processing procedure were calculated, compression tests were carried out. Basing on preliminary experiments the masses and sintering modes of rectangular shape forms used for equal channel angular pressing were figured out. The possibility in principle to carry out the process of equal channel angular pressing of porous sintered samples without metal damage was shown.

The adhesive lap joints are extensively used in various engineering fields. Various methods were proposed to increase the strength of the lap joint. This paper presents the lap joint's characterization by applying three grades of adhesives in different material properties along the bond line. The stiffest adhesive is employed in the middle bond line, then gradually, those with a lower modulus of elasticity are placed at the ends of the lap joint. This technique reduces the stress concentration at the joining ends, so the stress distribution becomes smoother. Finite element analysis is used to model this problem in two dimensions. One of the adherent edges is applied to the fixed support, and the other end is subjected to tension. The analysis results show that the use of tri-adhesive changes the shear stress distribution along the bond line flatter and increases the strength of tri-adhesive lap joints compared to those single type adhesive applied individually.

The paper presents the experimental and numerical investigations of the tensile properties of bamboo-glass fibres hybrid reinforced unsaturated polyester composites. The stacking configuration was GGBBBGG and GBGBGBG, with G and B, respectively denoted BFRP and GFRP. The hybrid composites were manufactured using a resin infusion technique. It was found that the tensile strength of the GGBBBGG was higher than that of GBGBGBG, but the elastic modulus seemed not significantly different. Hence, the glass fibres positioned at the outer layer (as skin of a sandwich composite) gave the better tensile properties than that of the alternating configuration. Numerical work utilising an extended finite element method (XFEM) had been undertaken, and a reasonable agreement on the failure load was found between the numerical and experimental results. However, the numerical load-displacement curves were underpredicted, which might be due to the load train of the testing equipment and also, the model did not include delamination within the layers.