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In this paper, polypropylene (PP) melt blown non-woven fabric is treated by atmospheric He, He/O2 or He/CO2 glow discharge plasma. The variation of the surface hidrophilicity of PP sample is experimentally investigated by the surface water contact angle. The results show that the surface water contact angle firstly has a sharp decline and then up to saturation. It is worth noting that the time the water contact angle is up to saturation greatly shortens when a spot of O2 or CO2 are added into the atmospheric He. In addition, when the PP samples are treated by the atmospheric glow discharge plasma, it is necessary of selecting a right applied voltage.

In this study the dynamic Smagorinsky model (DSM model) and an algebraic model for the subgrid turbulent kinetic energy have been implemented into KIVA3VLES code to investigate the atomization and evaporation processes of diesel spray in a constant volume vessel. Based on the experimental results of the liquid and vapor phase distributions as well as the results obtained by the differential subgrid scale kinetic energy (K-equation) model, the paper reveals the influence of the turbulent kinetic energy model on the fuel spray prediction. Computational results show that by combining the DSM model and the algebraic subgrid turbulent energy model, the turbulent diffusion of droplets can be reasonably simulated, the liquid penetration and the predicted liquid and fuel vapor mass fraction contours are close to the experiment results. At the same time, the turbulent kinetic energy given by the DSM model is in agreement with the results by the K-equation model, but with less computational cost..

The development of materials with high damping and energy absorption properties in the form of bulk materials or coatings is today a target for designing components and structures with improved durability and survivability to serve in fields such as aeronautical, mechanical, civil and environmental engineering. This paper presents the results of the dynamic mechanical characterization conducted on reinforced polyurea composites. The mechanical properties of two types of composite materials utilizing the polyurea elastomer as a matrix are compared with those of the pure polymer. The composite materials show a substantial increase of the damping ability. Such materials can be produced in the form of coatings and successfully applied for maximizing the damping of mechanical and structural vibrations or for limiting the damage effects of impact events on structures and components.

The paper studied the effect of fuel injection pressure and fuel supply advance angle on characteristics of butanol diesel blend engine.First,the results shows that when the volume ratio of butanol diesel is constant ,the fuel consumption and HC emission are the least under 20°CA.With increase of fuel supply advance angle ,the exhaust smoke emission and CO emission decreased largely under high load, but NOX emission increased largely. When the fuel supply advance angle is constant ,with the increase of volume ratio of butanol diesel ,the fuel consumption increased gradually, the exhaust smoke emission decreased largely, HC emission increased clearly, CO emission decreased largely but NOX emission increased.Third,with increase of fuel injection pressure,the exhaust smoke emission decreased largely ,NOx emission changed a little ,CO and HC emission increased largely.

Grinding aids to increase grinding efficiency in cement production are materials that can produce large amounts of high-quality cement in a short time by reducing surface energy by preventing particle agglomeration and improving fluidity. In the paper, a grinding aid using glycerol-waste antifreeze(GAP) is prepared and its effect on the grinding properties of clinker is investigated in contrast to that without the grinding aid. The results are as follows: The angle of repose of the cement powder added with GAP decreases as the grinding time increases (decreases by 3.8° when the grinding time is 60 minutes), indicating that it increases the flowability of the powder. On the contrary, the residual amount of 45µm sieve is also significantly reduced (4.6% decrease) and the specific surface area increases (30.5m2/kg), which results in an increase in the grinding efficiency. In the size range of 3 to 32µm, it increases the particle content, makes the particle size distribution uniform, the 7d and 28d activity index of the powder is improved by 5% and 6%, respectively, and increases the compressive strength of the cement. In addition, it is confirmed that the performance of the TEA grinding aid and the grinding aid are similar, and are very effective in terms of economy.

The sudden emergence of novel coronavirus CoVID-19 in China during the end of last year and its outburst all around the globe thereafter have raised serious questions about their instant management and diagnostic measures as it is infecting humans around in an exponential manner. The implementation of nanotechnology could perhaps ingenerate the rising distress due to the spread of the disease as the conventional antiviral drugs just control the symptoms. Nanoparticles drug delivery systems are engineered technologies that use nanoparticles for targeted drug delivery and controlled release of therapeutic agents. Nanoparticles based approach can replace the treatment with a more promising one that could meet these challenges. Understanding molecular pathogenesis of CoVID-19 infection is very important to exploit the nanoparticles to fight against it. A lot of nanostructures have been developed with antiviral and antibacterial properties for a variety of drug delivery and biomedical applications. The need of the hour is to exploit nano research to develop effective diagnostics tools, drugs, vaccines to treat and prohibit infection. In this paper an attempt has been made to understand the role and potential of various nanoparticles to inhibit CoVID-19 infection and its toxicity effects.

In this paper, charge control mechanism and carrier features have been precisely investigated in InxGa1-xN/InN/InxGa1-xN based quantum-well double heterostructure high electron mobility transistors (QW-DHEMTs). A study of charge control in the InxGa1-xN/InN/InxGa1-xN structure is performed by self-consistently solving Schrödinger equation in conjunction with Poisson’s equation taking into account the spontaneous and piezoelectric polarization effects. The potential profile and the distribution of electron density in the channel as a function of gate voltage are investigated here. A large conduction band offset of about 2.2eV is obtained for the proposed device for In content x=0.05, which ensure better carrier confinement and higher sheet charge density. The influence of In composition(x) and doping concentration of InxGa1-xN upper barrier on sheet charge density and carrier distributions in channel is also presented. This analysis provides a platform to investigate the InN based QW-DHEMTs and to optimized their design.

The paper presents a series of experimental researches performed using the design of experiments method RSD (Response Surface Design) for modeling and optimizing the welding process of PE 100 pipelines, used in natural gas distribution. In this sense, the aim was to analyze the influence of controllable factors such as pressure, temperature and time on the objective functions, aiming to obtain certain characteristics of the welded joint. By modeling the welding process, based on the results obtained, an optimal welding procedure was established and validated to meet the conditions imposed on the objective functions.

Air contains oxygen, nitrogen, etc. The gas separated technology and mixed method could increase or decrease the certain components of air. Changing the concentration of the component has a great influence on soot formation of diesel engine. The influences of excess air coefficient and the oxygen, nitrogen proportion of inlet air, the initial temperature and the initial pressure on PAHs (the soot precursor) formation of diesel engine were discussed in this paper. The results showed that the coupling model of diesel PAHs could predict the reaction temperature, the concentration of the reaction intermediates (CO, CO2 and O2), and the ignition delay during the combustion progress accurately. The concentration of the soot and its precursor PAHs could be decreased effectively by changing the proportion of the oxygen and nitrogen in the inlet air. After increasing the excess air coefficient, the numbers of the reaction intermediate free radicals (H and OH) were increased and the concentration of aromatic hydrocarbons was decreased. The beginning angle of chemical reaction was advanced by increasing the initial temperature and pressure. And it is beneficial to decrease the concentration of PAHs.

Microchannel heat sink plays a vital role in removing a considerable amount of heat flux from a small surface area from different electronic devices. In recent times, the rapid development of electronic devices requires the improvement of these heat sinks to a greater extent. In this aspect, the selection of appropriate substrate materials of the heat sinks is of vital importance. In this paper, three boron-based ultra-high temperature ceramic materials (ZrB2, TiB2, and HfB2) are compared as a substrate material for the microchannel heat sink using a numerical approach. The fluid flow and heat transfer are analyzed using the finite volume method. The results showed that the maximum temperature of the heat source didn’t exceed 355K at 3.6MWm-2 for any material. The results also indicated HfB2 and TiB2 to be more useful as a substrate material than ZrB2. By applying 3.6 MWm-2 heat flux at the source, the maximum obtained surface heat transfer coefficient was 175.2 KWm-2K-1 in a heat sink having substrate material HfB2.

Raw oil palm fronds (OPF-R) converted into biochar (OPF-B) by torrefaction processes at temperatures range of 200 °C to 300 °C. This study aims to evaluate OPF-B performance to reduce iron ions in artificial solutions and peat water. Batch adsorption carried out at room temperature by stirring (175 rpm) using an orbital shaker. Some parameters observed included optimum torrefaction temperature, optimum conditions of Fe ions adsorption (optimum pH and contact time) and sorption isotherm. Metal content measured using atomic absorption spectroscopy (AAS). Functional groups on material surface characterized using Fourier Transform Infrared (FT-IR). Torrefaction at 260 °C produces biochar with the highest efficiency in removing iron ions. Both functional groups C=O and C-O attributed to lignocellulose on OPF-B were diminished and absorption band of aromatic (C=C) increased which caused by torrefaction. The optimum conditions for removal of Fe ions at pH 5 and 30 minutes contact time. Adsorption process follows the Langmuir Isotherm which indicates the formation of a monolayer with qmax 111.11 mg/g. Amount of 0.025 g OPF-B able to reduce iron concentration from 13.960 mg/L to 0.746 mg/L in 100 mL peat water (has complied with Indonesian clean water standard for iron concentration).

Y-shaped carbon nanowires as a multi-branched carbon nanostructure have potential applications in electrical nano-devices. In this paper, we report the synthesis of Y-shaped carbon nanowires obtained from ethanol flames. These Y-shaped carbon nanowires have different morphologies from one to another. It is interesting that there are two Y-junctions on individual carbon nanowires. According to our experimental results, the growth mechanism of Y-shaped carbon nanowires has been discussed and a possible growth model of these Y-shaped carbon nanowires has been proposed.

This paper presents optimisation of hot press forming using design of experiment for high hardness properties at maximum cooling water temperature and minimum quenching time. Samples were boron steel blanks of 60x50 mm dimension. Hot press forming was conducted using a hydraulic press machine with 20 tonne maximum load. Results of this research work show that parameters obtained by single response optimization through desirability analysis route will increase hardness by 66.72%. The hardness properties of samples were between 477 and 551.4 HV(0.1). These findings were important to design tailored ultra-high strength automotive components at different process parameter settings and to reduce production cost consumption and improve production rate.

TiC – Fe composite coating was produced on AISI 1020 steel by the tungsten inert gas (TIG) cladding process to increase the hardness and wear resistance properties of the substrate. In this paper authors have investigated the effect of process parameters on the microstructure and hardness value of the coated layer. In this TIG cladding process the variable parameter is only current, whereas the other parameters such as scanning speed, standoff distance, and voltage and gas flow rate are fixed. Fe and TiC powders were mixed in the proper ratio of 80wt% - 20wt% and 90wt% - 10wt% respectively. The microstructure and micro-hardness value of the samples were investigated by the scanning electron microscope (SEM) and Vickers micro hardness tester. The result of SEM shows the distribution of the coating powder in the cladded zone. Micro hardness profile shows the variation of the hardness value in the cladded zone as well as in the substrate. The hardness value decreases with increase in distance from top surface of the cladded layer, which is due to difference in cooling rate. Also, the hardness value of cladded layer decreases with increase in current from 140A to 150A. The maximum hardness value of cladded layer was achieved as 262 HV0.05with 140A current and composition of 90 wt.% - 10wt% (Fe - TiC), which was nearly two times higher than that of the as received AISI 1020 steel substrate. Keywords TIG, Microstructure, Micro hardness, Titanium Carbide (TiC), Iron (Fe) powder.

The aim of this paper is to perform a study on how the elevated temperature and gradient of temperature affect the natural frequencies of aluminum honeycomb plate. This study is carried out for temperature range between 200K and 800K, and gradient temperature (ΔT) across the thickness direction of the plate between [0-500K]. Different honeycomb plate geometries have been selected for the analysis, by changing the core thickness, skins thickness and cell size. The obtained results show that the effect of the temperature is noticeable. At temperature 800K, the natural frequencies decrease by 16.1% in comparison to their values at ambient temperature (300K). That means, high temperature makes the material suffers from weak rigidity, which furthermore contribute to high decrease of all the frequencies. In addition, investigations carried out in this work relate to the modal analysis of the honeycomb plate, under various gradients of temperature across the core of the plate. The obtained results show that the gradient of temperature has an effect on the modes of vibration of the honeycomb plate. This effect becomes significant when the gradient of temperature is very high. At ΔT equal 500K, the natural vibration modes decrease by 9.5% in comparison to the case where no gradient of temperature (ΔT = 0K) is applied between the two faces of the plate. Keywords: honeycomb panel; aluminum; natural frequency; finite element method; temperature.

The effect of four different niobium(From 0-0.1%) addition on the mechanical properties of allotriomorphic ferrite (FGBA)/ granular bainite (BG) air cooling bainitic steels has been investigated in this paper. The results show that (1) The 0.06%Nb steel acquired superior strength and toughness combination by applying 1250°C×60min solution treated, finish rolling at 850°C, and air cooling. The corresponding mechanical properties of the thick plate(30mm) is: σb>1050MPa, σ0.2>700MPa,δ5>17%,Akv>90J. (2) The addition of niobium refine the grain size of FGBA, and promoted the transformation of bainite structure. With the increase of niobium content, the refinement of ferrite grain and bainitic cluster is improved. (3) More refined M-A island is acquired by the small addition of niobium. According to M-A Analysis tools and transversal methods, with the rise of niobium content, the volume fraction of M-A island increase from 21% to 35%, and the average size of M-A island decrease from 1.1μm to 0.7um. (4)It is suggested that 0.02-0.06% niobium can improve the mechanical properties of the steel obviously. However, excess addition of Nb (0.1%) deteriorates the impact toughness obviously. (5)Under the synthetic roles of the microstructure refinement and precipitation strengthen, 60-160MPa yield strength improvement has been acquired in the low carbon air cooling bainitic steel by the small addition of niobium. (6)This steel is with low production cost since the alloying element Mn is cheap.

In this paper, the hot compression tests were performed to study on deformation-induced pearlite transformation in vanadium microalloyed eutectoid steel. The results showed that volume fraction of deformation -induced pearlite were higher and the pearlite were spheroidized better under lower strain rate and higher strain in vanadium microalloyed steel. Ferrite grains and granular cementites were further refined through vanadium microalloying combined with deformation-induced pearlite transformation .Vanadium dissolved in γmatrix could retard deformation-induced pearlite transformation under low strain, vanadium carbides precipitated due to strain-induced precipitation eliminate the retardation when the strain was increased to a certain extent. Under heavy deformation, ferrite grains and granular cementites in vanadium microalloyed steel were finer compared with vanadium free steel.

Dredging is the available method to clarify eutrophic lake water for some engineers in recent years. This engineering may cause at least two negative influences on water environment, (a) pollution by dredging would occur during the operation, and (b) long-term effect degrade with some lake become dirty subsequently. Changes of the concentration of TP after the engineering of dredging are the focus in this paper. The content of total carbon (TC) and total nitrogen (TN) change at the same time for different original concentration of TP. Five grade original concentration of TP was simulated and the changing law was presented with the process of duration (D) and the change of temperature (T) as the independent variables. The results indicated that the concentration of TP decreased almost to 50% of their original ones respectively. But the changes of concentrations of TN and TC abide by the distinguished rule.

This paper examines and present the findings of the physical and mechanical properties of concrete containing rice husk ash (RHA), and the blend of rice husk ash with calcium carbide waste (RHA-CCW). Concrete cubes, cylindrical and beam specimens containing different percentages of RHA and RHA-CCW by weight of cement (5, 10, 15 and 20 %) were cast. Compressive strength test was carried out after the specimens were cured in water for 7, 14, 28 and 56 days. Test for tensile and flexural strength was carried out after 28 days curing. Initial and final setting time test was carried out on mortar specimens with the same percentage of RHA and RHA-CCW. Bogues model was used to determine the elemental and compound composition of cement when blended with the RHA and RHA-CCW. From the results obtained, the compressive strength of RHA-CCW concrete increases as cement is partially replaced with RHA-CCW content, with the maximum strength attained at 5 % replacement. RHA concrete attains it maximum strength at 10 % replacement. The maximum compressive strength results obtained for both RHA and RHA-CCW concrete were higher than the strength of plain concrete (0 % replacement) by 1.1 % and 14.7 % respectively. Interestingly, results obtained for the tensile strength also shows a similar pattern of strength development with that of compressive strength. The flexural strength properties of concrete was improved upon when RHA-CCW was used in concrete compared to RHA. The results of setting time test for RHA mortar showed a decrease in setting time, while the reverse was the case for RHA-CCW mortar. In conclusion, provided adequate curing is maintained, the used of RHA-CCW gives a better performance in concrete than RHA. However, they both perform better in concrete than the plain, and can be used as additives in concrete production.

In this paper, the Mg-Al hydrotalcite-like compound (Mg-Al-HTLC) was synthesized by hydrothermal method at 373K. Structure and morphology of Mg-Al-HTLC was obtained with X-ray diffraction (XRD), scanning electron microscope (SEM) and Fourier transform infra-red spectroscopy(FTIR). A series of polar and non-polar molecules were used for probes, surface properties of Mg-Al-HTLC was studied by inverse gas chromatography (IGC) at 353K, 363K, 373K, 383K respectively. The retention volume was utilized for evaluating the free energy of adsorption (-ΔGSP), the dispersive component of the surface energy(γsD), as well as the enthalpy and entropic component(ΔHSP, -ΔSSP). XRD results reveal that the Mg-Al-HTLC has high crystallinity and perfect layered structure. The results of IGC show that Mg-Al-HTLC would adsorb straight-chain alkanes spontaneously, and the values of γsDwere similar at all temperature. It reveals Mg-Al-HTLC is a material with particular characteristics of both acid and base. This study illustrates that, as a method to evaluate the surface properties of material , IGC method is dependable and significant.

Mica-based pearlescent pigments are widely applied in plastics, cosmetics, automobiles coatings and other fields, but very few applications in high temperature field are found as their poor heat resistance. In this paper, phlogopite is chosen as a new substrate which is coated by Fe2O3(doping with La3+) in order to improve the high temperature resistance and luster of the new developed pearlescent pigments. According to the X-ray diffraction (XRD) and scanning electron microscopy (SEM) results, it is found that Fe2O3nanospheres were coated on the surface of phlogopite homogenously. Colorimeter data imply that doping La3+can improve the color saturation and purity of pigments apparently. And the optimum amount is 3% lanthanum nitrate addition in this work.

In this paper the technological basics of machining the nickel-based superalloy Inconel 718 with a self-propelled rotary tool and an actively driven rotary tool are presented. The advantages compared to conventional machining with fixed round indexable inserts are discussed. In a series of experiments the influence of the tool rotation and modification of the process parameters to the chip formation process and characterization of the surface area of the workpiece are investigated. By using a multitasking lathe with a milling spindle further experiments are conducted. Thereby the influence of the direction of the tool rotation, the relative speed between tool and workpiece and the variation of the penetration angles are analysed.

The main objective of this research is to synthesize silk sericin and silk sericin powder for turbidity removal of synthetic turbid water. Silk sericin used as coagulant aid in this study was extracted from silk cocoons by boiling them with 0.5% (w/w) Na2CO3solution at 90°C for 60 min. Synthetic turbid water with the initial turbidity of about 50 NTU, 75 NTU, and 100 NTU, the turbidity removal efficiencies 89.2±5.41%, 90±3.48% and 87±4.31% respectively. For the powder silk sericin, the turbidity removal efficiencies 96±0.77%, 88±2%, and 96±1.73% respectively. Introduction

Zirconium alloys are solid solutions of zirconium or other metals. Zirconium has very low absorption cross-section of thermal neutrons. Zirconium has high corrosion resistance, ductility and hardness. Zirconium is mainly used as a good refractory metal. Zirconium can be manufactured by using standard fabrication techniques. In the present scenario zirconium alloys are used in water reactors for the cladding of fuel rods in nuclear reactors in nuclear technology. We use the composition of zirconium alloys as more than 94.5 weight percentage of zirconium and less than 2.45 weight percentage of copper which are added to improve mechanical, thermal properties and corrosion resistance. This paper first focuses on the study of thermal properties of Zirconium. And this particularly concentrated on variation of Coefficient of Thermal Expansion by varying temperatures by using Dilatometer and as well as ANSYS

Welding copper and its alloys is usually difficult to achieve by conventional fusion welding processes because of high thermal diffusivity of the copper, which is at least 10 times higher than most steel alloys, in addition to this, there are the well-known disadvantages of conventional fusion welding represented by necessity of using alloying elements, a shielding gas and a clean surface. To overcome these inconveniences, Friction Stir Welding (FSW), a solid state joining process that relies on frictional heating and plastic deformation, is being explored as a feasible welding process. In order to achieve an increased welding speed and a reduction in tool wear, this process is assisted by another one (TIG) which generates and adds heat to the process. The research includes two experiments for the FSW process and one experiment for tungsten inert gas assisted FSW process. The process parameters that varied were the rotational speed of the tool [rpm] and the welding speed [mm/min] while the compressive force remained constant. The purpose of this paper is to correlate the evolution of temperature, tensile strength, elongation and microscopic aspect with the linear position on the joint (local process parameters) for each experimental case and then make comparisons between them, and to identify and present the set of process parameters that has the best mechanical properties for this material.

Friction Stir Welding, abbreviated FSW is an innovative joining process. The FSW is a solid-state welding process with a lot of advantages comparing to the traditional arc welding, such as the following: it uses a non-consumable tool, it results of good mechanical properties, it can use dissimilar materials and it have a low environmental impact. First of all, the FSW process was developed to join similar aluminum plates, and now, the technology was developed and the FSW process is used to weld large types of materials, similar or dissimilar. In this paper it is presented an experimental study and the results of it, which includes the welding of three dissimilar aluminum alloy, with different chemical and mechanical properties. This three materials are: AA2024, AA6061 and AA7075. The welding joints and the welding process were analyzed considering: process temperature, micro-hardness, macrostructure and microstructure.

The paper presents the results of a mathematical model of the material flow during Friction Stir Welding (FSW) of aluminium alloys using a Finite Element Analysis. The authors presented their work on a two-dimensional visco-plastic model, using User Define Functions (UDF) in a commercial CFD code (FLUENT). The model developed was validated by microstructural investigations on experimental FSW joints and by a comparative analysis of temperature distribution field of the experimental FSW joint and numerical simulated model. The results confirmed that the mathematical model describes with a good precision the material flow and temperature field during FSW process.

During Friction Stir Welding (FSW) process materials to be joined will be subject of intense mechanical and thermal processes, characteristic to this solid state welding process. As a result, the welded materials will suffer quick heating and cooling cycles that will be overlapping on large plastic deformation/flow of the materials, which will produce their phase and structural transformation as well as modification of their properties. The paper investigates the structural transformation of the materials and will analyse the influence between the FSW process and these transformations.

The nanocrystalline (NC) and ultrafine-grained (UFG) structures of metallic materials can lead to their extraordinary high strength. However, most of the papers on this topic consider deformation parameters of NC and UFG materials only for the case of quasi-static tensile tests. Characteristics of dynamic strength and fracture of such materials remain unexplored. This paper presents a study of the mechanical behavior of pure titanium Grade 4 with a coarse-grained (CG) and UFG structure under uniaxial compression with different strain rates. The UFG structure was provided using the method of equal-channel angular pressing. The dynamic compression was carried out on a setup with the Split-Hopkinson pressure bar. It is found that in the observed range of strain rates 10–3-3×103 s–1, the yield stress of the CG titanium increases by 20%, and does not exceed the yield stress of the UFG titanium. However, the yield stress of the UFG titanium remains close to a quasi-static value. It is shown that these strain-rate dependencies of the yield strength can be predicted by the incubation time approach. The calculated curves show that at strain rates above 104 s–1 the yield stress of the CG titanium becomes higher than the yield strength of the UFG titanium.

This paper designed and completed the different polymer dosage of recycled concrete, was prepared by adding amount was 7%, 14%, 21%, 14% styrene butadiene latex recycled concrete, recycled rubber powder recycled concrete and ordinary concrete block, the cube compressive strength and damping performance test. The cube compressive strength of concrete test according to the ordinary concrete mechanics performance test methods, specimen is 150×150×150 mm cube specimens, pressure testing machine loading speed is 0.5 MPa per second. The concrete damping performance test is carried out according to the free attenuation method, with the hammer vibration test device, the test piece is T type. Based on the damage form of specimens, the compressive strength and damping performance analysis, and compared with ordinary concrete as the benchmark analysis test results show that the polymer recycled concrete cube compressive strength failure process and failure pattern basic consistent with common concrete. In the water/cement ratio, sand ratio, and amount of material per unit volume is the same, under the condition of polymer recycled concrete cube compressive strength is lower than normal concrete, damping performance is higher than that of ordinary concrete, the compressive strength is inversely proportional to the damping sexual relations.

With the depletion of fossil energy, biology material is getting more and more attention. Bark, as a kind of renewable resource, need to be utilized urgently and reasonably. The larch bark was very extensive in northeast and the use of larch bark is limited to make tannin. However, the whole process produced much bark residue, which could not be utilized effectively. In this paper, based on the content of total phenolic hydroxyl groups, the in-situ synthesis reaction of the larch bark with formaldehyde was performed in different ratios. FTIR analysis was adopted to characterize the synthesized products. After air-drying, the synthesized product was pressed into a bark-based composite under pressure of 10~25 MPa. The effect of pressure and molar ratio of phenols and formaldehyde on the properties of the composite were analyzed. These results indicate that, pressure and molar ratio were both vital factors. The composite with higher molar ratio of phenol and formaldehyde had better abilities of anti-moisture, but the molar ratio of 1:2 made the strongest composite. With the increasing of pressure, the hardness of the composite was greater. For the composite made under 20 MPa and the molar ratio of 1:2, its hardness was 23.41 MPa and its max load was 415.83N. Its thickness and diameter swelling rate of moisture absorption in 12 d was 1.87% and 0.68%.

In this paper it is presented the microstructure and wear resistance of FeNiCrMnCu high entropy alloy. High entropy alloys are composed by at least five metallic elements in equimolar or non-equimolare proportions. High entropy alloys a brand new category of metallic materials, appeared to be a new effort in materials science and engineering, which attracted great interest. To obtain FeNiCrMnCu high entropy alloy we used an 8000 Hz induction furnace. The chemical composition was determined by EDAX. Microstructural analysis was performed using optical microscopy and SEM (scanning electron microscopy), which showed that the FeNiCrMnCu high entropy alloy has a dentritic structure and form a solid solution. Choosing copper as the main element (copper tends to segregate in interdentritic region due to its positive enthalpy of mixing with many common elements) [1], along with the iron, nickel, chromium and manganese, led to obtaining a dentritic structure specify for solid solution, which, however, did not lead to a significant hardness for FeNiCrMnCu high entropy alloy. In this work we selected pure metallic elements like: Fe, Ni, Cr, Mn and Cu. The quantity of alloy developed has 1.5 kg. Friction and wear resistance were the studied by using a reciprocating sliding test machine, in a pin on disk configuration, using aluminum as counter face. Hardness value regarding FeNiCrMnCu high entropy alloy was 184 HV and medium friction coefficient value for FeNiCrMnCu high entropy alloys was 0.86 for 28 minutesc and 1.13 for the first 20 seconds.

The paper presents some aspects regarding the wetting conditions in aluminium – graphite composite. The wettability depends on several factors like the presence of the oxide skin at the melt surface, formation Al4C3 at the interface between Al and particles, temperature, pressure etc. In this paper, the conditions of perfect wettability of carbon by molten Al achieved under MCl–K2TiF6 molten salts (fluxes), alloying of the melt with surface active elements, heat treatment of reinforcement material and coating of the particles with a metallic thin layer.

The objective of this research work was to study the influence of the iron oxide phase resulted during steam oxidation of the sintered steels specimens obtained by powder metallurgy (P/M) route. Steam oxidation is a surface treatment applied to sintered iron parts, as an economic way to reduce the interconnected pores. In powder metallurgy products, the networks of pores are specific, who can be stress concentraions and can produce cracks in material. By steam oxidation treatment the interconnected porosity is closed by sealing them with iron oxides phases. Also, other properties of sintered PM steels are improved. The specimens analyzed in this paper were produced from atomised iron powders, compacted at room temperature at pressures of 600 MPa, sintered for 120 minutes at 1150o C in a laboratory furnace and then subjected to a continuous steam oxidation at 550o C for 60 minutes. Investigations on the structural, mechanical and abrasive wear properties were performed. The microstructure and the pore morphology of the sintered and steam oxidation samples were studied on using optical microscope.

The aim of this paper is to analyse the effect of the pore morphology on microstructural characteristics, mechanical properties and abrasive wear resistance of iron-based alloys subjected to a thermochemical treatment as carburizing in fluidized bed. The starting materials studied in this paper are represented by pre-alloyed iron base powder obtained by powder metallurgy (P/M) route. The powders were produced by water atomization with different particle sizes (< 45, 45-63, 63-100, 100-150, >150 μm). The raw powders have been mixed with 1% zinc stearate as lubricant and uniaxially compacted into cylindrical specimens at room temperature at 600 MPa. The disc dimensions are 8 6 mm. The green compacts were sintered at 1.150 °C for 90 minutes in a laboratory furnnace. After sintering, a thermochemical treatment was applied. The parameters for the carburizinng in fluidized bed are: temperature of 930 °C and time of 45 minutes. The microstructural characterization was carried out using optical microscopy. The porosity of studied samples were analyzed acording to their microstructural characteristics and chemical composition. The mechanical properties and abrasive wear of the sintered and thermochemical treated samples were evaluated. A correlation between porosity, mechanical properties and abrasive wear was established.

Galvanic sludge resulting from wastewater treatment is a hazardous waste that can be removed by disposal only after neutralization process. A chemically complex sludge is a mixture of hydroxides of the many heavy metals such us: copper, iron, nickel, chromium, cadmium and zinc. There is worldwide, a concern to develop methods and techniques for extraction and recovery of the metal compounds from sludge out of treatment processes of wastewater from metal plating works (washing wastewater and technological solutions) in order to reinsert them into existing industrial flows or to capitalize them in other industries, leading to a significant reduction of environmental pollution.This paper presents the results of the scientific activity in the laboratory with a view to recover Cr (VI, III) from two types of galvanic sludge: a fresh sludge from wastewaters treatment by Lancy technique and an old sludge, stabilized by disposal for many years. Chromium extraction was performed by alkaline sludge oxidation to obtain salts of chromium. The extraction efficiency was 84.20 % from fresh sludge (in one stage) and 93.19% from old sludge (in two stages).

Ground granulated blast furnace slag, red mud, wheat straw ash are secondary material which after alkaline activation can be used in the construction materials’ domain. Their disposal poses a threat to the environment, whereas by reusing them we would be able to reduce this negative impact. This paper describes the research carried out in order to synthesise some geopolymer recipes, which are based on ground granulated blast furnace slag, red mud and wheat straw ash, alkaline activated with sodium hydroxide or a solution made with sodium hydroxide and sodium silicate. Factors that influence the compression strength have been studied such as: the nature of the alkaline activator, the chemical composition of solid materials in the recipes and the curing time. The geopolymer samples have been dried at room temperature for 7 and 28 days, respectively, and after the compressive strength tests has been made. Following this research it has been found out that NaOH/Na2SiO3 activated geopolymer samples have shown a higher resistance in the compressive strength. From the SEM analysis it has been found out that the samples with a higher amount of ground granulated blast furnace slag in their composition had a more homogeneous and less porous design than those with a smaller amount of ground granulated blast furnace slag.

Oxide semiconductors have attracted increasing interest due to their potential in solving environmental problems. ZnO-based nanoparticles (NPs) are among the most investigated for efficient disinfection and microbial control.Iron-doped zinc oxide nanoparticles (Fe:ZnO NPs) were successfully fabricated through precipitation method at low temperature followed by thermal treatment. The obtained Fe:ZnO NPs were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and ultraviolet-visible (UV–Vis) spectroscopy. The effect of iron content on structural, morphological, antimicrobial and photocatalytic properties was investigated and discussed.The photocatalytic activity of the nanoparticles was tested by degradation of methylene blue (MB) solution under UV light for 60 min irradiation. The antibacterial activity was determined by paper disc method on Mueller-Hinton agar against the Gram-negative bacteria Escherichia coli (E. coli) and the Gram-positive bacteria Staphylococcus aureus (S. aureus) and compared to that of the undoped ZnO NPs. Consistent improvement on the photocatalytic and antimicrobial activity of Fe-doped ZnO nanoparticles was noticed.

Magnetorheological elastomers (MREs) are a kind of smart materials, which change the mechanical properties (viscoelastic characteristics) under the magnetic field action. In the paper the determination of damping properties (reactive force) of specimens made out of magnetorheological elastomers is presented. The specimens made out of MREs have been fabricated as a composite with matrix made out of silicone rubber with certain contents of magnetisable particles (carbonyl iron powder). The cylindrical specimens have been tested in compression loading, controlled by an electro-mechanic system. The MRE characteristics of the specimens have been determined in the presence of a magnetic field produced with an electromagnet (coil device). The reactive force occurring in the MRE specimen has been determined on the basis of the measured data during loading. The variation curves of the reactive force versus magnetic field induction are drawn. As a conclusion, the rigidity of the MRE specimen is increasing since the magnitude of the magnetic field induction is increasing.

Carbon fiber reinforced silicon carbide composite (Cf/SiC) is the new high temperature ceramic composite developed in recent years, widely used in the aviation, aerospace and other high-tech fields. In this paper, a variety of joining methods of Cf/SiC composite to metallic materials, including active filler brazing, solid phase diffusion welding, liquid infiltration joining, as well as chemical vapor deposition of niobium transition joining technology were introduced. At the same time, the features and disadvantages of each technique were evaluated. This review is intended to provide a comprehensive guide to the design and application of Cf/SiC composite joining to metals.

This paper describes a rapid formation of stimuli-responsive organogel from polyoxometalate-based hybrid, by simple mixing of gelator in N, N-dimethylformamide and toluene solution under ambient conditions.

The polymer electrolyte composed of poly (ethylene oxide) (PEO) and sodium iodide (NaI) as dopant salt was prepared by using solution casting method. Effect of temperature on the conductivity performance was studied by impedance spectroscopy in the temperature range of 303 to 343K. The linear variation of conductivity with temperature suggests the Arrhenius type thermally activated process. The effect of temperature on the conductivity is discussed on the basis of number, n, mobility, μ and diffusion coefficient, D of free ions. In this paper, n, μ and D were determined using impedance spectroscopy method.

In this paper, NixCo3-xTiO4 nanowire as anode materials was prepared by co-deposition method, and the characterized results showed that had good crystallinity by SEM. The cobalt and nickel were enriched in the surface in the sample by XPS. The catalytic performance of NixCo3-xTiO4 was studied by cyclic voltammetry and constant potential. The results showed that when the Co: Ni = 4:1, the temperature was 120°C, NixCo3-xTiO4 nanowires had high catalytic activity and good stability by the cyclic voltammetry and the steady state polarization curves.

This paper studies how the addition of Carbon nanotubes (CNT) influencing the properties, especially the mechanical properties and colorimetry of ethylene propylene diene rubber (EPDM)/SiO2 composites. The results show that the increased content of CNT can turn EPDM/SiO2 composites from lighter, redder, and yellower to darker, greener and bluer, respectively. The total color change (ΔE) of EPDM/SiO2 composites would be acceptable when the CNT content is below 3%. When the CNTs content reaches 4%, the tensile strength of EPDM is the maximum.

Modifications of red mud for activating available silicon (Si) by phosphates were carried on in this paper. And then the modified red mud materials were used to stabilize Cd in an ore soil. Results indicated that phosphates efficiently increase the content of available Si in red mud. In the stabilization, exchange Cd was decreased by 90.97% when using 5% potassium dihydrogen phosphate modified red mud, which was better than using raw re mud as the decrease was 77.08%. In rice pot soil, increases of residue Cd were positively correlated with the increases of available Si (P

The mechanical properties, including the compressive strength, flexural strength and adhesion strength of the rapid setting conventional and polymer-modified waterproof mortars are systematically compared in this paper. The polymer modification is demonstrated to increase the flexural strength and adhesion strength of the rapid setting waterproof mortar whereas it reduces its compressive strength.

The partial structure factors for liquid alloy In1-xSnx have been computed at varying concentration and temperatures using pseudopotential theory. The structure factor S(q) and pair correlation function g (r) have been determined using the hard-sphere approximation. The temperature dependent hard-sphere diameter σ (T) is estimated using Vσ=Vminr+12kBT criterion from the computed pair potential. The modified empty-core local pseudopotential, which represents the orthogonalisation effect due to s-core states, is used for electron–ion interaction with proper screening function. The only potential parameter, the core radius, is determined at different temperatures from the knowledge of structure factor. Intrinsic temperature effects have been studied through dimensionless damping term (see formula in paper) in the pair potential. The effect of temperature and concentration on structure factors is discussed to shed light on bonding in technologically important alloy. This used pseudopotential proved successful in explaining the structural properties of non-crystalline alloys at higher temperatures.

The paper discusses the electrochemical interactions of Co-Cr alloy with different physiological solutions and organic substances, containing different ions and different pH values, which should play a key role in the materials lifetime. The physical and chemical reactions are numerous and the passivity of the Co-Cr alloy is submitted to the influence of the liquid environment. Some electrochemical investigations were carried out for understanding and predicting the passivity and the corrosion resistance of Co-Cr alloy in three types of simulated body fluids (SBF), namely Fusayama Meyer artificial saliva (pH=5), Hank’s solution (pH=7.4), Ringer's solution (pH=6.6) and citric acid as organic solution. The reason of using another type of environment (other than SBF), such as citric acid is that this medium is a powerful oxidant and has a lower pH value (pH=1.8). This acid environment can influence the state (the formation and growth) of the oxide layer on the surface of the alloy. Research has shown different behavior of the cobalt chromium alloy according to the pH, the chloride content and the oxidizing nature of the environment. Co-Cr alloy biomaterial, immersed in four aqueous media reveals that there are different levels of stabilization of the potential and different current densities depending on the pH value. The Co-Cr alloy biomaterial is very sensitive to localized corrosion (pitting) in Hank solution.

The hydraulic turbine blades are made from stainless steels having a hard layer for the improvement of the hydro abrasive wear, corrosion resistance, and resistance to mechanical impacts in order to increase the reliability of the turbine. The thin films from stellite and tungsten carbide were obtained by the method: electrospark deposition because it has relatively low costs, are easy to obtain, the layers have a good adherence to support and the thickness can be variable in function of the established conditions. In this paper, the physical, chemical and mechanical properties of the samples will be determined using Scanning Electron Microscope (SEM), in order to emphasize the structure film-substrate and repartition of the deposition elements on the surface and in transversal section. Also, the samples were nondestructively tested using the electromagnetic sensor with metamaterials in order to establish the adherence of the thin films to the steel, proving the potential of this NDT techniques. The complex signal delivered by the sensor has been stored while scanning a 6x6 mm area. The processing algorithm involve the use of the bidimensional Fourier transform after filtering the initial signal using Walsh-Hadamard numerical filter.

The purpose of the present investigations is to study the effect of processing parameters on statistically controlled hot chamber die casting solution for Al alloy. The study presented in this paper is based on a macro model (based on Taguchi design). Castings prepared at proposed parametric settings (as per macro model) have been investigated for functional validation of the parts. The study suggested significant improvement in dimensional accuracy (ΔD) at proposed parametric settings and the process was found to be under statistical control.