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Natural fibers have been extensively studied as a reinforcement filler in obtaining composites, replacing partially synthetic fibers. The vast majority of these materials originate from agro-industrial waste with a high content of lignin and cellulose making it a very interesting material with low cost and good mechanical properties. The purpose of the study was to obtain a composite based on alkyl ketene dimer resin, for the manufacture of sustainable packaging, made of paper by adding a 10% (w/w) con-tent of green coconut fiber and sugarcane bagasse fiber, and evaluated the impact of the filler on the mechanical behavior of the systems. The studied material was characterized from mechanical tests, such as Ring Crush Test (RCT) and Concora Medium Test (CMT) evaluating the maximum resistance supported by centimeter in the pre-pared composites, by the specimens. Through the RCT tests, with 10% w/w fibers, it was possible to verify that the fiber from sugarcane bagasse reached an increase of about 1% in the reinforcement effect compared to pure paper, and a difference of up to 2% in strength mechanics in relation to coir fiber, and CMT tests shows the reinforcement effect of the presence of sugarcane bagasse fiber, with an increase of about 3% compared to pure paper, and with a mechanical strength higher by 1% compared to coconut fiber. Therefore, the study was funneled with sugar cane fiber, varying the content by 20 and 30 % (w/w), evaluating the impact on the dispersion of this filler in the polymeric matrix and, consequently, the mechanical response of the composite with these compositions. The conclusion of the study was that the system prepared with 20% (w/w) was the one that achieved the greatest optimization of the mechanical properties, evaluated by the tests. This type of material can be applied to obtain cardboard boxes with resistance to high loads, due to the achievement of good mechanical properties.

Currently, paper pulping production from woody materials has many disadvantages due to its high energy, chemical, water consumption, methane emissions, and deforestation. However, the use of non-woody materials solves these problems. This study focused on the use of non-virgin raw material (Enset leaf fiber) in pulp and paper making. Enset leaf residues are the primary solid residues after the steam plant is used for “Kocho” processing. This leaf fiber has a lignocellulose component, converting this residue into Pulp and paper is crucial in terms of economic and waste management via the Kraft process. It has a higher fiber quality, lower energy consumption, and high recoverability of the chemical raw materials used in the process. The chemical composition of the Enset leaf fiber was analyzed using the Technical Association of Pulp and Paper. It has an excellent fiber length (2.12±1.46mm), fiber diameter (26.55±15.6µm) and acceptable rigidity coefficient (1.05±0.07), and flexibility coefficient (125.23±0.04). The maximum pulp yield was obtained at a temperature of 120°C, NaOH concentration of 8%, and 40 min cooking time off, which was 69.92% w/w. The functional groups of the Enset leaf fiber and morphological characteristics of the fiber were investigated.

The characteristic pinched hysteresis behavior of memristors has been reported by stacks of a variety of materials. This paper aims to examine the principles of logic design using such two terminal memristive systems for high performance digital circuit applications. As against logic design with standard CMOS, the benefits of logic design with memristors have been stated. The realization and operation of memristor based AND and OR hybrid logic gates obtained by integrating memristors with standard CMOS logic have been discussed. The IMPLY and MAGIC logic families have been demonstrated by covering MAGIC NOR and NAND logic gate implementation with MAGIC NOR in detail. A qualitative comparison has been drawn towards the end of the paper to conclude on the suitability and application space for each of the logic families studied in this paper. This work also describes the hybrid CMOS-memristive logic family known as MRL (Memristor Ratioed Logic). With the addition of CMOS inverters, this logic family's OR and AND logic gates, which are based on memristive components, are given a full logic structure and signal restoration. The MRL family, in contrast to earlier memristor-based logic families, is compatible with conventional CMOS logic.

This paper mainly studies the composition of strengthening phase, characteristic precipitation temperature and composition range of strengthening phase in Ti-Al-Mo-Zr-Si medical titanium alloy, and the influence of element changes on the content and microstructure of strengthening phase. Promote the formulation of thermodynamic process of titanium alloy powder metallurgy, as well as the formulation of alloy hot working and solid solution aging process. In this paper, Panda thermodynamic software is used to calculate the multicomponent alloy thermodynamics and multicomponent phase diagram of titanium alloy materials. The effects of Al, Mo, Zr, Si and other elements on the precipitation of strengthening phase and the phase transformation content of solidification structure were obtained. It is found that the content of Mo is more than 2 wt.% β phase transition precipitation angle. Meanwhile, in order to avoid the excess of precipitates such as Mo5Si3 and M3Si, the content of Mo should be less than 4.6 wt.%. The content of Zr can be maintained at about 1.5 wt.%. If the aging precipitation of the material is considered, it can be controlled to be less than 2 wt.%. The content of this paper is the basis and improvement of titanium powder metallurgy technology and rapid prototyping technology.

Sustainable development requires green energy and low carbon footprint in manufacturing sector of photovoltaic systems. The electrical connections of photovoltaic cells need to have low electrical resistance in order to reduce the electrical losses and therefore to improve the performance of the photovoltaic panels. This paper aims to present researches related to bonding of wires that connect solar cells by using microwave technology. The microwave bonding has the main advantage that offers fast bonding but, in the same time, this technology does not offer stability of the thermal heating. Two different unwanted phenomena like thermal runaway and plasma arc discharge often lead to the damaging of copper and aluminum wires used in electrical connection. The study presented in this paper is focused on simulation of the thermal field developed in copper wires in order to optimize the bonding process and increase the quality of products. The simulation of the thermal field has been done using Fourier equations for conducting heating in copper materials and eutectic alloys. The simulation model has been validated through experimental heating using a 6 kW water-cooled microwave generator controlled by a matching load auto-tuner for best transfer of the power from generator to copper wires. The temperature has been measured in real time using an infrared pyrometer for metals with 2.3 μm spectral range and measurement range between 0o C and 7000 C. The study is finalized with elaboration of mathematical model for microwave-injected power as function for temperature developed in copper wires that can be applied with success in further microwave bonding applications of copper wires. In addition, the electrical resistance of bonded wires was measured in order to collect feedback for improving the microwave bonding process.

The transporting of sediments across watershed systems and their placement in reservoirs causes expensive issues for the operators of dams in many different nations throughout the world. In addition to the reservoir's functional capacity steadily decreasing as sediment settles in it, silt removal is a sensitive and challenging process that frequently necessitates taking the reservoir out of service, which is practically unachievable in dry and semi-arid regions. De-silting by hydraulic dredging has recently become a necessity to increase their longevity. But during this operation there are load loss exists so it is necessary to find solutions to reduce it. The present paper revealed that use the Sodium Tripolyphosphate as a reducing agent of the friction factor during the hydraulic dredging of dams. To carry out this study, a rheumatic characterization of dams sediments and dams sediments -sodium tripolyphosphate mixtures was carried out using a torque controlled rheometer (Discovery Hybrid Rheometer DHR2 from TA instrument). The flow curves as a function of dose of sodium tripolyphosphate added to dam sediments were analysed by the modified Cross model. It is clearly shown, in this work, when the quantity of sodium tripolyphosphate is less than of 0.4 % causes a decrease in the yield stress, the zero shear rate viscosity (lower Newtonian plateau) and the infinite shear rate viscosity (upper Newtonian plateau). However, when dose of sodium tripolyphosphate is greater than the critical dose, the the yield stress, the zero shear rate viscosity (lower Newtonian plateau) and the infinite shear rate viscosity (upper Newtonian plateau) are increased. As a result, this study find that the increase on thixotropic behavior of dams sediments is occurred by the addition of sodium tripolyphosphate in a concentration ranging between 0.2 wt% and 0.8 wt% to 40 wt% and 45 wt% of dams sediments. The study also demonstrated that adding of 0.4 wt% of sodium tripolyphosphate to 40 wt% and 45 wt% dam sediments decreased the friction factor by 96% and 25% respectively.

In this paper the effect of lattice friction stress on the process of dislocations annihilation is considered using dislocation dynamics method. It is shown that if dislocations of the opposite sign are located in the area where their own tension is greater than the friction stress, they annihilate. Consideration of this fact allows to connect the microscopic processes of annihilation with evolution of dislocation density in the sample under small external stresses and unloading. The area in which annihilation occurs is calculated to be proportional to the square of the friction stress/shear modulus ratio.It is also shown that the parameter responsible for the rate of dislocation annihilation depends on the cube of the ratio of the friction stress to the shear modulus, because it is inversely proportional to the number of annihilating dislocations and the time in which a dislocation pair annihilates.

This paper proposes a deep learning model for predicting the durability benchmark on concrete specimens. The durability benchmark on concrete samples is commonly estimated throughout the Ultrasonic Pulse Velocity measurements. This test establishes a relationship with concrete durability taken into consideration the material's homogeneity. The model proposed in this paper is feed by standard laboratory tests as input parameters, making the model a practical and efficient alternative to predict durability concrete benchmark, saving time, short-cut laboratory work, and avoiding sophisticated instrumentation use. Furthermore, it is an attractive alternative to the need for sophisticated instrumentation for estimating the Ultrasonic Pulse Velocity. The outcomes depict a high predictive accuracy about of 96% in the validation stage. In addition, the model was tested by a new dataset with different properties to demonstrate robustness and certainty in the model. Finally, the model achieves an impressive accuracy of 95.89% in the new validation dataset.

In this paper, a hollow square cross-section carbon fiber/epoxy composite beam was designed and manufactured. Evaluation of the beam behavior considered orientation and stacking sequence, aiming to reduce the number of layers and weight. Finite element method (FEM) was used to simulate the performance of the composite beam under 3-point bending and using three failure criteria, Tsai-Hill, Tsai-Wu and maximum stress. In order to identify the input parameters for the model, flat composites were tested under tension and compression. It was concluded that a minimum of 12 layers of unidirectional carbon fiber were required to reach the required load (44.5 kN). The prototype was successfully fabricated by vacuum-infusion process and subjected to 3-point bending test. The experimental failure load was within the predicted range by the Tsai-Hill failure criteria and maximum stress.

The recent developments in dielectric elastomers (DE) are spectacular. Currently, a DE as an actuator, 0.15 g of acrylic sandwiching SWCNT electrodes, is capable of lifting a weight of 8 kg by more than 1 mm at a speed of 88 msec. In the near future, DE motors could be used to drive electric vehicles. Moreover, the DE can be used as a high-efficiency sensor with the same structure. With a diameter of 20 mm and a thickness of 0.5 mm, it can accurately measure pressure from several kg to 150 kg. In addition, reversing this DE actuator (DEA) movement also enables high-efficiency power generation. In other words, when the DEA is stretched or pushed, it generates electric power. Single wall nanotubes (SWCNTs) were used as an electrode, and an acrylic DE power generation cartridge with a diameter of 80 mm was used. When the center of the DE power generation cartridge is pushed by about 15 mm, a power of 33.6 mJ is generated. Using these two DE cartridges, it was possible to charge a secondary battery through a DC converter. In addition to this power generator, practical research and development of power generation using wave power, wind power, waste heat, and fluids (ocean currents, water currents, etc.) is progressing. In this paper, we have described state-of-the-art DEAs, DE generators (including the case that the power generated locally by microgenerators are consumed locally), and DE sensors and explained their usefulness.

Spinel ferrite nanoparticles are potential candidates for multiple biomedical applications. Spinel ferrite nanoparticles have been studied extensively for understanding physical, chemical, electro-optical as well as magnetic properties which are fascinating due to cationic distributions corresponding to tetrahedral sites and octahedral sites in a cubic phase. Biocompatibility and large magnetic moment are basic requirements in spinel ferrite nanoparticles for efficient functioning in specific application purpose. Fe3O4 (magnetite) is an important member of spinel ferrite group with high chemical stability and ferrimagetic material property at nanodimension. Superparamagnetic state and biocompatibility of magnetite (Fe3O4) spinel ferrite nanoparticle has already been proven. Spinel ferrite magnetite nanoparticles have been developed based on precipitation of iron oxide using ferric and ferrous ions at the ratio 2:1 in alkaline media at and above 100°C. The experimental parameters have been set to synthesize pure and uniformly sized magnetite nanoparticles. No other phases of iron oxides were detected other than magnetite spinel phase in the XRD result. The average crystal size has been determined from XRD peak broadening. Absorption spectra were investigated using UV-Vis Spectrometer and FTIR. Thermal and magnetic measurements were carried out Digital Scanning Calorimeter and SQUID Magnetometer. One sample of the prepared nanoparticles with polymer coating of polyvinyl alcohol has been studied for superparamagnetic nature. Superparamagnetic particles show saturation value of magnetization 51.26 emu/g at 100 K. ZFC-FC curves for two samples with polymer coating of polyvinyl alcohol and hydroxy-propyl methyl cellulose have also been studied. Keywords: Spinel Ferrite, Magnetite, Ferrimagnetism, Transition metal oxide, Superparamagnetism. Statements and declarations Competing Interests: The authors declare that there is no competing financial interest that are related directly or indirectly to the reported work in this paper. Conflict of interest: There is no conflict of interest. Acknowledgements The Authors are grateful to IISER Bhopal, CRF facility for providing instrumentation facility to characterize magnetic properties. We acknowledge thanks to Lovely Professional University for providing us necessary characterization technique for the XRD analysis and thermal analysis.

Road markings regulate and direct traffic by conveying specific information. It is of great significance to develop new road marking materials and improve the visibility of marking materials for improving traffic efficiency and ensuring traffic safety. This paper summarized the development status of various reflective road markings at home and abroad. In addition, the energy storage luminescent fluorescent/phosphor marking lines in road marking was emphatically generalized to evaluate the advantages and disadvantages of different improvement methods. Overall, strontium aluminate doped with Eu2+ co-doped with Dy3+ (SrAl2O4:Eu2+, Dy3+) phosphors and self-luminous pavement for energy storage had great prospects in improving road safety and reducing energy consumption.

Monodispersed Ag nanorods were synthesized using a one-pot synthesis method. These Ag nanorods normally manifest dual surface plasmon resonance (SPR) peaks. This work presents a study of the variation of SPR peaks with variation in the shape of Ag nanorods. Shape variation was achieved through the degradation of a shape-controlling agent (PVP in this work) under white light irradiance with silica passivation to halt further shape variations. This paper also reports the growth & characterization of thin films of the synthesized rod-shaped silver nanoparticles on glass slides along with studies on band pass filter characteristics of the as-synthesized nanoparticles.

This paper reports the synthesis of ZnS Quantum Dots (QDs) embedded in PVA by aqueous precipitation method and its application in antibacterial as well as to find or estimation of Escherichia coli (E.coli) concentration by using ZnS/PVA QD based mem-mode nanodevices. The as-synthesized ZnS/PVA samples are characterized by UV-Vis spectroscopy (UV), Photo luminescence (PL), X-ray diffraction (XRD), Transmission Electron Microscopy (TEM) and Scanning Electron Microscopy (SEM). Antibacterial property of ZnS/PVA QDs against gram positive (S.aureus) as well as gram negative (E.coli) are tested. The antibacterial property is found to be more in S.aureus in comparision to E.coli. Mem-behaviour of the as-fabricated devices is observed through electrical characterization. COMSOL MP Software is used for simulating I-V characteristics. The voltage gap is found to be a promising parameter for estimating E.coli concentration with ZnS/PVA QDs as active material and an electrical circuit is presented

The cutting fluid plays a significant role in minimizing heat generation and chip removal process during the machining of materials, hence improving tool life and surface finish of the workpiece. Many researchers have focused on minimum quantity lubrication (MQL) among the existing methods on the application of the coolant as it reduces the usage of coolant by spurting a mixture of compressed air and cutting fluid in an improved way instead of flood cooling. The MQL method has demonstrated to be appropriate as it fulfills the necessities of ‘green’ machining. Additionally, considering current environmental issues and provisions for safe healthy working conditions at the workplace, it is important to divert machining processes towards an eco-friendly path. Hence, the focus of research has been shifted to MQL using eco-friendly lubricants for green and sustainable manufacturing processes. In this review paper, the effect of different vegetable oil-based biodegradable coolants like castor oil, coconut oil, palm oil, etc. for different machining process parameters like cutting force, cutting temperature, surface finish, tool wear, etc. has been reviewed. It is observed that proper selection of cutting parameters along with lubricant through MQL can provide enhanced machinability to get desired outputs.

Forging tools must be able to withstand very strong mechanical, thermal, tribological, and chemical stresses. The extent to which a tool can withstand these stresses depends on the material used and its pre-treatment as well as the heat and surface treatment, i.e. the load capacity. The ratio of stress to load capacity determines how high the tool life of a forging tool is. This paper deals with the variations in the tool life of forging tools using the example of a specific industrial stage sequence and production conditions. Due to a large number of influencing variables that have an effect on the tool during the entire tool life history, the focus of this work is placed on influencing variables of the forming process. Based on real production parameters of a forging company, which are recorded during a period for the investigation, the process data are analyzed about an influence on the tool life. The investigation focuses on four influencing variables, namely the subjective assessment of the end of the tool life, the interaction between the forming stages, production interruptions, and the cooling and lubrication of the forming tools. For the parameters that are not yet recorded during the trials, promising available measurement methods are identified and tested under laboratory conditions. One example of this is the recording of the actual spray quantities that are sprayed onto the tool surface before the forming process. The results of the investigations show that the tool life fluctuations can be reduced by about 16% and as a consequence, the average tool life can be increased by about 13%.

The process of mechanically activating chemical bonds usually involves applying external force. Since mechanical chemistry can be performed without solvents or with minimal amounts of solvent (catalytic quantities), it has become an imperative synthetic tool in multiple fields (e.g., physics, chemistry, and materials science) and is an attractive greener method for preparing diverse molecules. Catalysis, organic synthesis, solid-state medicinal preparation, metal complex synthesis, and many other chemistry fields have benefited from sustainable methods. The purpose of this paper is to shed light on the benefits of using mechanochemical methods to produce a pharmaceutical crystal that is composed of dendrimer nanocrystals. Consequently, we describe and examine the importance of mechanical procedures in forming dendrimers and pharmaceutical crystals in this review.

The sulfur content present in graphene oxide prepared by Hummers' method has only been addressed by few papers so far. By modified Hammers method we synthesized thermally stable in ambient environment multilayer sulphur-doped graphene oxide. The samples were heat treated in an electrical furnace setup at different ambient temperatures and their crystallite size and linear coefficient of thermal expansion were extracted from Raman band intensity peak ratio as a function of temperature. We found unusually large (in comparison with graphene oxide) contraction on heating of multilayer two weight percent sulphur-doped graphene oxide with carbon to oxygen ratio of 2.3 in a narrow temperature range (308-318 K) with the lowest value of the linear thermal expansion coefficient of -18 ppm 1/K. Based upon an examination of the synthesized sulphur-doped graphene diffractograms, it is suggested that negative thermal expansion stems from the phonon backscattering by the sulphur impurity sites and the edges of the layers. The obtained experimental results have potential practical applications for fabrication of solar cells, sensors, lubricators, thermal actuators and also wavelike (second sound) thermal transport structures.

Plastic waste disposal is among the most challenging problems of the current era. Therefore, new methods and applications for the utilization of waste plastics are increasingly needed. To find them, it is essential to research and develop the material properties of recycled plastics. The effect of different ultraviolet light (UV) stabilizers on the color stability, melt properties and tensile properties of mixed waste plastics blends was studied in this paper. The mixed waste plastics collected from two different waste sources were prepared as specimens by injection molding, and studied with two different types and loading amounts of UV stabilizers. UV absorbers (UVAs) and hindered amine light stabilizers (HALS) were used as UV stabilizers. A specimen produced without the addition of a UV stabilizer was used as a reference specimen of both the blends. After the accelerated weathering, the addition of a UVA provided an improved, smaller change in color than the addition of HALS. Among the tensile properties, the addition of UV stabilizers clearly improved the tensile strength and tensile modulus for almost all the studied specimens. Additionally, the melt properties of both the studied plastic blends were found to be increased by the addition of UV stabilizers.

In this paper, aiming at the heat resistance and thermal deformation process of titanium matrix composites 0 vol.%, 2.5.vol.%, 5.vol.%. Thermal simulation experiment of titanium matrix composites with different (TiB+TiC) strengthening phase content. The measurement accuracy of material displacement is 0.01 mm. The compression is 70%, and the strain rate is 0.1 mm/s and 0.01 mm/s respectively. Compression tests at different strain rates and temperatures were carried out. The experimental results show that when the (TiB+TiC) 5vol% titanium composite is deformed at 0.01mm/s low strain rate, the peak stresses corresponding to 25°C, 250°C,350 °C and 500°C are increased to 1096MPa, 835MPa, 646MPa and 416MPa respectively. Under the condition of high strain rate of 0.1mm/s, the peak stresses corresponding to 25 °C, 250 °C, 350 °C and 500 °C are increased to 1230 MPa, 896 MPa, 723 MPa and 471 MPa respectively. The deformation law of stress rheological curve is roughly the same, and the high temperature zone has good plastic deformation ability. The titanium matrix composite has high compression rheological mechanical properties and good high-temperature plastic deformation ability. It is the preferred material component for the preparation of titanium matrix composite and powder forging.

The present paper analyzes the differences in behavior and resistance to erosion through vibrating cavitation, between the bronze structures CuSn-12C resulting from two volumetric thermal treatments of hardening and tempering. The analysis was performed on the basis of macro and microscopic images, as well as on the basis of the histogram in which the values ​​of the reference parameters used in the laboratory custom and prescribed by the international norms ASTM G32-2016 are compared. This shows the dependence of the degree of erosion as a function of the temperature of tempering heat treatment, after hardening, as a result of microstructural changes and the hardness of the surface attacked by cavitation. The experimental research is performed on the standard vibrating device within the Cavitation Erosion Research Laboratory of the Politehnica University of Timișoara.

Due to its characteristics, DD13 steel is recommended for various applications in the automotive field (including in the manufacture of components for car bodies). The paper presents solutions proposed by ISIM Timisoara for welding of DD13 steel, as alternative solutions to conventional welding processes. One solution that has proven to be viable for joining DD13 steel is the friction stir welding process (FSW). In terms of the quality of the welded joints obtained by applying the classic FSW welding process, these welds were excellent. In an attempt to obtain other benefits, mainly related to the efficiency of the welding process, ISIM Timisoara has developed research programs for the study and application of other methods based on the FSW process principle, namely: - hybrid friction stir welding ultrasonic assisted FSW-US; - friction stir welding in inert gas environment FSW – IG. The important effects due to the application of these methods are: improving (as appropriate) the degree of plasticization of the materials to be joined and increasing the degree of mixing of the materials as result of ultrasonic assistance of the FSW welding process; improvement of the welding process by reducing the pressing forces of the tool during welding, with an effect on increasing the service life of welding tool; respectively improving the aspect of the weld and some mechanical characteristics of the welded joints (at tensile tests, respectively static bending test). The obtained results showed that the two methods derived from the classical FSW welding process, can be used in industrial applications, with important benefits.

This paper covers the literature review of the work by author, who have been involved in the subject of machine element repairing from the techno-economical point of view. Positive aspects of repairing, as opposed to purchasing new parts are shown and discussed. All of the examples given as part of the literature review are related to real, practical problems. It was concluded in all cases, that the repairing of damaged parts was the better option, since not only did it cost significantly less, it also noticeably decreased the equipment downtime, as there was no need to wait for the new part to be delivered.

Among other parts made of brass there are also the blades and the rotors of the hydraulic machines, respectively ship propellers, which during operation are degraded by cavitation erosion. As a result, most of the researches, including the most recent ones, are focused on the morphological analysis of structures eroded under the impact of micro-jets and shock waves, produced by cavitation hydrodynamics. The goal is to create new materials, but also to use new treatment technologies to increase cavitation resistance. As the literature is quite poor in studies related to the materials resistance to cavitation erosion, respectively treatments and technological procedures of it’s improvement, this paper presents the research results on the behavior of vibration cavitation erosion, carried out on three sets of CuZn39Pb3 brass samples, subjected to volumetric heat treatments of hardening for putting in solution at 800°C, followed by tempering at 250°C, 400°C and 600°C. The characterization of the behavior and the cavitation resistance of the structures resulting from the applied heat treatments is performed based on macroscopic images, taken at different representative periods, SEM images at the end of the test duration and values ​​of specific parameters recommended by ASTM G32-2016. The analysis highlights the differences caused by the change in structure by varying the temperature, but also the hardness of the surface exposed to the cavity. Thus, of the three treatments, it is found that the best resistance to cavitation is conferred by the structure resulting from hardening at 800°C, with tempering at 250°C.

The manufacture of photovoltaic panels for the production of sustainable energy also involves the stage of electrical connection of the cells in the panel structure. This electrical connection is made by soldering of copper strips on the negative electrode of the cell. During the bonding process, due to the temperature of approximately 220-240°C at which the connecting strip is continuously heated, cracking processes of the upper layer of glass from the cell surface were identified. For this reason, it is necessary either to heat to lower temperatures, a solution that is not viable due to the melting temperature of the solder alloy which usually exceeds 210°C, or a different dosing of the heat flux. The solution proposed in the paper is to create a variable heat flux that allows the melting of the solder alloy, but at the same time to reduce the thermal load of the glass support layer. Through the proposed variant, the energy dosing is done with the help of a heating system consisting of two sources, an ultra-acoustic energy source and a classical resistive source. The resistive source provides an amount of energy to ensure a temperature in the range of 60-140°C, the difference to the melting point of the solder alloy being transferred locally by ultrasonic pulses. Research has highlighted the need to limit the range of values of the pressure of the circular sonotrode, which positively influences the mechanical stress of the photovoltaic cell, but also leads to a reduction in the joining speed. The dosing of the two components of the total energy, the one coming from the resistive source and the one coming from the ultra-acoustic vibration source is decisive for the efficiency of the joining process and for the quality of the soldered joint. Microscopic analyses revealed micro-cracks of the glass surface layer at forces higher than 100 N. Areas with lack of soldering for resistive heating at temperatures lower than 130oC were highlighted, the difference of 90-110°C being achieved by the contribution of ultra-acoustic energy.

Welding tools are a determining factor in obtaining welded joints with desired characteristics. The international community pays great attention to research aimed at establishing the optimal characteristics of friction stir welding (FSW) tools. With the development of the FSW welding process with its own contributions, ISIM Timisoara has developed complex research resulting in the conception and design of (innovative) FSW welding tool solutions. A very important factor especially when welding high hardness materials is the durability / lifespan of FSW welding tools. The paper presents general considerations regarding the qualities that FSW welding tools must meet in general, but also ISIM achievements in the field of design and operation of welding tools. Studies regarding operating behavior of welding tools made of sintered tungsten carbide P20S, in terms of service life (wear), both in the case of applying the classical FSW welding process and the method of friction stir welding in inert gas environment (FSW-IG), when joining steels with wide industrial use (304L stainless steel, respectively DD13 steel), are also presented. Concrete data is presented with values of the degree of wear of the tools in the unit of time, in their critical areas: tools made of X38CrMoV5 steel alloy used for welding aluminum alloys with different characteristics, respectively tools made of sintered tungsten carbide P20S used for welding S 235 JR + N steel and 304L stainless steels.

With the development of new energy vehicles, it is necessary to develope new fast charging cathode materials for lithium ion batteries. This paper reports a simple carbon thermal reduction routine to synthesize layered LiMoO2 cathode for Li-ion batteries. Impurity-free micro-crystalline powders were synthesized by one-step method with a thermal treatment at 800°C for 5 hrs under N2 atmosphere. The structural, morphological and electrochemical properties of LiMoO2 were characterized by using X-ray diffraction pattern (XRD), scanning electronic microscopy (SEM), charge/discharge cycling and electrochemical impedance spectroscopy (EIS). The diffraction results indicate that the prepared sample has a layered hexagonal structure related to α-NaFeO2. The secondary particles are in order of 2.0 μm length on average with homogeneous distribution. The initial discharge capacity of LiMoO2 is 110.9 mAh·g-1 at 0.1 C, and the capacity can still remain 92.8 mAh·g-1 after 100 cycles. The good cycling performance and high rate discharge performance are attributed to the smaller charge-transfer resistance revealed by EIS results.

The synthesis and characterization of spin-coated Al-doped ZnO (AZO) thin films with varying Al concentrations (0%, 5%, 10%, 15% and 20%) onto glass substrates have been demonstrated in this paper. The structural, electrical and optical properties of the spin-coated thin films have been investigated by Scanning Electron Microscopy (SEM), Energy Dispersive X-Ray (EDX) analysis, Van Der Pauw method and UV-visible spectroscopy. The EDX study shows well-defined peaks which confirm the presence of only Zn, O and Al and no other impurities in the films. The increase of Al and decrease of Zn weight percentages with increasing doping level confirms the effective substitution of Zn by Al. SEM of the surfaces of the films shows that undoped ZnO films contain particle agglomeration which is reduced with Al doping and the surfaces of the films gradually became more uniform. The thickness of the AZO films varied from 86 to 699 nm with increasing Al doping concentration. The electrical conductivity of the films increased up to ~ 7 × 10-2 (Ω.cm)-1 due to doping with 5% Al concentration. The optical transmittance highly increased above 95% in the visible range with the introduction of Al dopant and it kept rising with the increase of Al concentration. The optical energy band gap of undoped ZnO increased from 3.275eV to 3.342 eV with 5% Al doping.

The strong vacuum ultraviolet (VUV) radiation absorption and energy transfer mechanism is detected in SrF2: Gd3+, Eu3+ fluoride phosphor. The phosphor is synthesized by a wet chemical method followed by reactive atmospheric process (RAP). The Powder XRD analysis shows structural purity. The photoluminescence characteristics of SrF2:Gd3+, Eu3+ phosphor is studied using the remote access of 4B8 window (VUV beamline) of the Beijing Synchrotron Radiation Facility (BSRF) China. In this paper the mechanism of Energy transfer from the Gd3+ to Eu3+ through the cross relaxation process is investigated. The down-conversion of energy from VUV (142 nm) to visible with quantum efficiency (QE) around 124% has been detected. The PL excitation and emission characteristics of the prepared phosphor advocates it as a prominent material for the applications in mercury free fluorescent lighting (MFFL) & Plasma Display Panel.

In this paper, a color-tunable light emitting diode LED with two laterally arranged single quantum wells (SQWs) is designed, and simulated. In this work, III-nitride materials are used. The structure has been numerically investigated using the ATLAS simulation software. The proposed structure has three electrodes. This gives the opportunity to emit violet (420 nm) or green (560 nm) light individually. Furthermore, it can emit simultaneously a mixture of both colors, and at a certain mixture ratio the white light is obtained with chromaticity coordinates ( x = 0.3113, y = 0.3973). The lateral arrangement of the two SQWs reduces the negative effect of photon absorption; which will give good external quantum efficiency (EQE). The structure has a big importance in the application of the solid-state lighting, especially in the white light generation.

Fire though an important component of life, the devastating effect of fire accidents is a threat to life and materials. Thus, the prevention and control of fire are becoming a serious concern. Hence, it is no wonder that fire retardant materials (FRMs) are slowly becoming ubiquitous in our daily lives. To control the fire in an unexpected fire accident or to prevent fire accidents FRMs are becoming essential requirements. To save material or life, fire retardant materials have been used for long knowingly or unknowingly. However, the understandings of chemistry and thermochemistry of materials helped for the development of efficient FRMs. Diversified materials, processing methods, and application modes have been developed, and all of them become specific depending on the nature and origin of the fire. In this regard, the inorganic FRMs form a distinct category due to their low cost, easier processing and wider choice of application mode without leaving any additional environmental burden either to land or the atmosphere. In this paper, different fire retardant materials and their properties with the abilities to tackle the fire at different temperatures are reviewed. The primary characteristics of fire and the thermal behaviours of FRMs as well as changes in behaviour/properties when FRMs are treated with certain synergistic systems are discussed. The importance of composition, morphology and structure of FRMs on the efficiency and applicability are discussed. Recent developments on the synthesis and characterisation of different types of FRMs and their composites have been elaborated. The effective applications and the commercial products based on their properties are also briefly covered. Overall, the review provides an overview of existing information on fire retardant materials in terms of their synthesis, processing, usability and limitations, with a prime attention on the process-structure-property relations of these materials.

Photopolymerisation of 2-Hydroxyethyl methacrylate (HEMA) through the use of N,N-Diethyldithiocarbamato-(1,2)-propanediol (DCPD) was studied. The photoinitiator DCPD was synthesized from sodium N,N-Diethyldithiocarbamate (NaSR) and 3-chloro-1,2-propanediol. For the photochemical decomposition of the C – S bond, UV light at 254 nm is used. The role of the monomer concentration, reaction time and DCPD to HEMA mol ratio on the conversion of HEMA to PHEMA were studied in this paper. It was found that percentage conversion of HEMA increased both with the rise in concentration of monomer and reaction time. Further, living radical nature of the poly2-Hydroxyethyl methacrylate (PHEMA) was ascertained by the photo block copolymerization of methyl methacrylate (MMA) with PHEMA to form PHEMA-b-PMMA. The PHEMA and PHEMA-b-PMMA were characterized by FTIR, 1H-NMR, Thermogravimetry.

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.

In this paper, the flexural strength of concrete using alccofine and nano-silica was investigated experimentally and analytically. 15% alccofine and 3% nano-silica by weight of cement was used as a binary and ternary blend in three concrete grades M40, M50, and M60. Compressive strength and flexural strength were obtained experimentally by curing the specimens in water for 28 days. The empirical equation between compressive strength and flexural strength in the form of fr =bfc’n was obtained using regression analysis. The proposed empirical relation was compared with relations given by a code of practices and the relations reported by other researchers for predicting flexural strength using the compressive strength of concrete. The accuracy of the proposed empirical relation was validated using various statistical equations. From the experimental results, it was found that the cubic compressive strength and flexural strength of ternary blended concrete mixes using alccofine and nano-silica was 20 to 29% and 32 to 39 % higher compared to the control mixes. From the values of statistical equations, the proposed relation was found accurate. It showed less error compared to other relations and can be used to determine flexural strength results based on compressive strength data.