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The primary aim of the investigation is to synthesize graphene oxide at room temperature and fabricate a flexible free standing graphene oxide thin film. Modified Hummers technique was employed for the synthesis of graphene oxide using graphite as the starting material. Graphene oxide is a layered material consisting of hydrophilic oxygenated functional groups on their basal planes and edges. Graphene-oxide thin film has been fabricated via solvent-evaporation technique. Functional, elemental and structural analysis of the samples was performed using several characterization techniques.

Graphene provides a perfect platform to explore the unique electronic properties in two-dimensions. However, most electronic applications are handicapped by the absence of a semiconducting gap in pristine graphene. To control the semiconducting properties of graphene, doping is regarded as one of the most feasible methods. Here we demonstrate that graphene can be effectively doped during chemical exfoliation of highly ordered pyrolitic graphite in organic solvents. Layered structure of graphene sheets was confirmed by confocal Raman spectroscopy and doping was probed by analyzing shift in Raman peak positions and transistor transfer (IDS-VGS) characteristics.

Reduced graphene oxides were synthesized by chemical reduction of graphite oxide using hydrazine hydrate as well as by high temperature-high vacuum thermal exfoliation at 900-1100°C. The samples were characterized using Raman spectroscopy. From the Raman spectra, it is inferred that hydrazine reduced and thermally exfoliated samples were found to consist of two and three to five layers. The change in the amount of sp2 rings present in GO with increase in exfoliation temperature is studied.

Graphene/CeO2 quantum dots (QDs) composite was investigated towards the liquid petroleum gas (LPG) at room temperature. Graphene was synthesized by electrochemical exfoliation of graphite. The composites of graphene/CeO2 QDs was prepared by mixing 20 wt.% of graphene in constant 1g of CeO2. The chemiresistor of 20 wt.% composite possesses optimum value of sensing response and excellent stability.

In the present study, MnO2 nanotubes are synthesized by hydrothermal method and Pt/graphene by co reduction of hexachloroplatinic acid and graphite oxide. The formation of MnO2 nanotubes and Pt/graphene are confirmed by X-ray diffraction, scanning electron microscopy, transmission electron microscopy. MnO2 nanotubes are mixed with Pt/graphene is applied as the ORR catalyst in proton exchange membrane fuel cell. The single cell measurement is carried out after fabricating the membrane electrode assembly and polarization curves are recorded at different temperatures and the results are discussed.

We report here a simple and efficient method for fabrication of reduced graphene oxide (rGO) thin films. Graphite oxide can be completely exfoliated to produce aqueous colloidal suspensions of graphene oxide (GO) sheets by simple ultra-sonication. Graphene oxide thin films were reduced towards graphene by exposure to hydrazine vapor, ammonia vapor and microwaves. The samples were characterized using X-ray diffraction (XRD) and UV-Visible spectroscopy (UV-Vis).

Graphene oxide monolayer sheets were transferred on Si and SiO2/Si substrates by Langmuir-Blodgett technique and were exposed to ammonia plasma at room temperature. The monolayer character of both graphene oxide and plasma treated graphene oxide sheets were ascertained by atomic force microscopy. X-ray photoelectron spectroscopy and Raman spectroscopy revealed that ammonia plasma treatment results in enhancement of graphitic carbon content along with the incorporation of nitrogen. The conductivity of graphene oxide monolayers, which was in the range of 10−6-10−7 S/cm, increased to 10−2-10−3 S/cm after the ammonia plasma treatment. These results indicate that the graphene oxide was simultaneously reduced and N-doped during ammonia plasma treatment, without affecting the morphological stability of sheets.

The large amount of graphene oxide was prepared by modified Hummers method, and which was then characterized by FT-Raman, FT-IR spectroscopy. Also the supercapacitor behavior of graphene oxide was studied ionic liquid. Here we observed that the graphene oxide shows best supercapacitor behavior in ionic liquid.

Here, we report electronic properties of graphene field-effect transistor in a magnetic field of 9.0 tesla. Raman spectroscopy on graphene sample prepared by anodic bonding method shows it to be of the highest quality. The observation of charge neutrality point at a positive gate voltage is due to hole doping in the sample from the immobile oxygen ions created during anodic bonding process. Hysteresis observed in the longitudinal resistance (between source and drain) while sweeping voltage at gate in a loop may be due to high viscosity of polythene oxide matrix for mobile Li ions. The longitudinal resistance as a function of gate voltage Vg shows that both kind of charge carriers (electron and hole) can be doped in graphene, which is further ascertained by the Hall measurements.

In our present work, we describe a simple method for uniform coating of Graphite oxide (GO) onto flexible polyurethane (PU) foams. These PU foams loaded with GO were made electrically conducting by converting insulating GO to conducting graphene by chemical reduction process without damaging the foam properties. These PU foams loaded with graphene were characterized by SEM and TGA. The morphology, thermal properties and pressure dependent electrical conductivity of these foams was studied. The electric current increased by five orders of magnitude due to applied pressure.

The need to explore the use of renewable energy resources, in any way possible, is now considered as inevitable. The focus of this project is to utilize solar energy for the production of hydrogen from water. Both sunlight and water are available in abundance. As sunlight is available during day time, the photohydrogen produced can be stored and converted to electricity, whenever needed. The production of photohydrogen requires not only sunlight, but photocatalyst as well. A series of Ni/TiO2 photocatalysts with different Ni loading (2, 5, and 10 wt%) were prepared via wet impregnation method followed by calcination at 300°C for a duration of 2 hours. Hydrogen production from water was conducted by using a 250 W/m2 halogen lamp for one hour. The best performing photocatalyst was 10 wt% Ni/TiO2 giving 3.4 mL of hydrogen from H2O compared to the lower activity of TiO2 which produced only 1.9 mL of hydrogen from H2O. These values were obtained by using steady state light intensity; where else the available s...

Graphene oxide sheets were transferred on Si and Ti substrates by Langmuir-Blodgett technique and were reduced by hydrazine vapor treatment followed by annealing in vacuum/inert atmosphere. A comparison of Raman spectra of reduced graphene oxide on Si and Ti shows that the reduction process is more effective in the later case and results in the formation of RGO with higher graphitic carbon content, exhibiting spectral features closer to those of graphene monolayers.

From the first-principle study, it is shown that the introduction of strain in a monolayer graphene enhances its chemical reactivity and hence it becomes more reactive than the pristine one. The intermolecular interaction between graphene and molecular hydrogen increases with increase in strain in the graphene plane leading to adsorption of hydrogen with suitable binding energy. Since graphene sheets can be freely suspended without any substrate we can stretch the sheets by adjusting distance between the clamped edges of the holding frame. In this way stacks of stretched graphene sheets can be constructed and a good hydrogen storage system can be obtained.

Few layer graphene (FLG) had been successfully grown on polycrystalline Ni films or foils on a large scale using DC Plasma Enhanced Chemical Vapor Deposition (DC PE‐CVD) as a result of the Raman spectra drawn out of the sample. The size of graphene films is dependent on the area of the Ni film as well as the DC PE‐CVD chamber size. Synthesis time has an effect on the quality of graphene produced. However, further analysis and experiments must be pursued to further identify the optimum settings and conditions of producing better quality graphene. Applied plasma voltage on the other hand, had an influence on the minimization of defects in the graphene grown. It has also presented a method of producing a free standing PMMA/graphene membrane on a FeCl3(aq) solution which could then be transferred to a desired substrate.

The micromechanically exfoliated monolayer graphene on SiO2, Al2O3, and HfO2 are investigated by Raman spectroscopy and AFM measurement. The pristine graphene seems to have stronger adhesion and higher carrier concentration when the dielectric constant of the underlying oxide is higher. It is found that high vacuum annealing significantly increases the interaction between graphene and the oxides and Raman G and 2D bands shift to higher wavelength. The high vacuum annealing for graphene on HfO2 increases carrier concentration of up to ∼10 times with a corresponding Fermi level shift of ∼0.65 eV although that of graphene on SiO2 induces a biaxial compressive stress as high as 4 GPa on graphene. As the three dielectrics evaluated in this work are the most commonly used gate dielectrics in field‐effect transistors, these findings will be useful in fabrication of graphene based field‐effect transistors.

Using the pulsed deposition technique, the growth of GaN on graphite substrate is possible. Because of the two‐dimensionality of graphite, the strain for the lattice mismatch due to the growth of GaN is absorbed by the topmost layer of graphite. We confirm that the electronic and the atomic structure for the interface of the grown GaN on graphite is almost similar to the interface of GaN on a single graphene layer using the density functional theory.

In this study, a membrane aeration/filtration combined bioreactor (CMBR) was constructed, and the effect of alternate cycle by CMBR on membrane fouling and oxygen utilization efficiency (OUE) was investigated. Results showed that under the condition, when the alternate cycle was 0.75∼3h, the ΔTMP (TMP value of the time when a filtration cycle was over) of CMBR maintained a basically constant value during the 6 days’ continuous operation, which implied the CMBR achieved a favorable effect of the membrane fouling relieving. Too short or too long cycle would lead to a gradual increase of ΔTMP. OUE of CMBR increased with the extension of the alternate cycle. Thus, it suggested that the optimal alternate cycle of CMBR should be 3h.

This research aim to analysis bioethanol purification process. Bioethanol from cassava has been produced in previous research and the ethanol from molasses was taken from Bekonang region. The production of bioethanol from cassava was carried out through several processes such as homogenization, adding of α‐amylase, β‐amylase and yeast (Saccharomyces c). Two types of laboratory scale distillator have been used, the first type is 50 cm length and 4 cm diameter. The second type distillator is 30 cm length and 9 cm diameter. Both types have been used to distill bioethanol The initial concentration after the fermentation process is 15% for bioethanol from cassava and 20–30% ethanol from molasses. The results of first type distillator are 90% of bioethanol at 50° C and yield 2.5%; 70% of bioethanol at 60° C and yield 11.2%. 32% of bioethanol at 70° C and yield 42%. Meanwhile the second distillator results are 84% of bioethanol at 50° C with yield 12%; 51% of bioethanol at 60° C with yield 35.5%; 20% of bioethanol at 70° C with yield 78.8%; 16% of bioethanol at 80° C with yield 81.6%. The ethanol from molasses has been distillated once times in Bekonang after the fermentation process, the yield was about 20%. In this research first type distillator and the initial concentration is 20% has been used. The results are 95% of bioethanol at 75° C with yield 8%; 94% of bioethanol at 85° C with yield 13% when vacuum pump was used. And 94% of bioethanol at 90° C with yield 3.7% and 94% of bioethanol at 96° C with yield 10.27% without vacuum pump. The bioethanol purification use second type distillator more effective than first type distillator.

The method of preparing carbon nanotube (CNT) by milling of graphite particles in water followed by high temperature annealing is proposed and the mechanism discussed. Transmission electron microscopy (TEM) and X‐ray diffraction (XRD) line broadening analysis reveal that cleavage of the graphite particles occurs preferentially along the out‐of‐plane π bonds. Carbon K‐edge near edge X‐ray absorption fine structure (NEXAFS) of the milled graphite shows an increased sp3 character of the C=C bonds, but no major bonds rupture in the graphene sheets. The annealing at 1400 °C for 4 h of the milled graphite in argon results in formation of multiwalled carbon nanotubes accompanied with a number of coiled and twisted stacks of graphene sheets. The increased structural disorder of the milled graphite and presence of iron contaminations facilitate the rolling up of the cleaved graphene sheets during annealing.

The main development directions in modern power engineering industries are related to increasing the output power and improving the economic and ecological performance of the engine. The group of pistons inside the engine highly affects the reliability of the reciprocating engine and its power and economic performance. This paper presents a mathematical model developed by the authors to calculate the hydrodynamic characteristics of the oil layer, taking into account the transverse motion of a two-piece piston, piston skirt deformations and variable viscosity of the lubricant in the interface. The conducted research is aimed at developing a piston design that will provide liquid friction in the piston skirt-cylinder junction during the entire operation cycle. Particular attention is paid to the evaluation of the accuracy of the obtained results. The results of the study of the computational mesh size in the numerical solution of the elastic-hydrodynamic problem on the accuracy of calculation of the hydrodynamic characteristics of the oil layer in the piston skirt-cylinder junction considering the piston skirt deformations are presented. This paper provides an example on studying the influence of the piston skirt profile on the hydrodynamic characteristics of the oil layer and the lateral movement of the piston skirt. The calculations were carried out using program codes developed by the authors.

The paper presents the results of the assessment of the applicability of structured laser illumination in combination with Rayleigh scattering or spontaneous Raman scattering methods for evaluating the local density and temperature distribution in a premixed methane flame. The examples presented in this paper show that the use of structured laser illumination makes it possible to obtain a signal free of background and reflected light by registering the scattering signal only at one S-polarization of the laser. The best quality of image reconstruction was obtained using a grating with a line spacing of 0.5 mm. Gratings with a larger step gave a strong blurring and loss in spatial resolution, a grating with a smaller line spacing during reconstruction led to the formation of secondary structures with lines.

This paper proposed the modelling and simulation of generator protection for power system using digital reverse power relay. The operations of the power plant are often interrupted by the reverse power generation. Therefore, generators need to be closely monitored and controlled. In this study, 11 kV synchronous generators are connected to 220 kV load through a step-up transformer, and a new model of reverse power relay is added for generator protection. The reverse power relay proposed in this paper is a digital relay with high accuracy and high reacting speed. Several cases based on various types of mechanical inputs to the generator were studied to test the operation of the reverse power relay. This simulation was done using MATLAB/Simulink. The results show that the 11 kV generator protection is successful with this new model reverse power relay. Besides, the simulation results were similar result compared to the theory result. From the simulation results, the integral output of the relay will reach the threshold value ‘L’ whenever there is a reversed power flow fault found in the system. Consequently, the relay will be triggered to provide protection for the generator. This model has been added into online resources of MATLAB Power System Tools. In addition, this model may also help the engineers to develop the analytical skills under various conditions.

Recently assembly line balancing (ALB) is an ultimate focus issue in manufacturing industries for optimizing both common goals which were the number of workstations and the production rate. Metaheuristic is one of optimization problem-independent technique. This paper focusses on the short review of metaheuristic optimization in solving assembly line balancing problems. Hence, to produce a summary of the review, this paper selects some publications for the past 3 years from year 2016 to 2019. From the review shows the metaheuristic optimization that often used are Artificial Bee Colony (ABC), Ant Colony Optimization (ACO), Differential Evaluation (DE), Evolutionary Algorithm (EA), Genetic Algorithm (GA), Particle Swarm Optimization (PSO) and Simulated Annealing (SA). Besides, GA is most frequently used to solve ALB problems. Finally, recommendation for future research for solving ALB Problems using metaheuristic optimization are discussed.

Recently Molten Salt Reactor (MSR) gains more interest among nuclear researchers due to its promising competitiveness and safety features. ThorCon MSR (TMSR500) is this kind of reactor projected to be built in Indonesia. Due to a limited number of proven operating reactors and limited knowledge of reactor characteristics, several aspects have to be studied, such as neutronic features, material, fuel circulation, fuel management, etc. This paper reveals some important neutronic safety features of MSR, referring to ThorCon design, such as temperature reactivity feedback of fuel, moderator, and reflector. Void reactivity feedback and neutron energy spectrum behavior during voiding were also examined by performing MCNP6 calculations and nuclear data ENDF/B-VII. Full core geometry was modeled, and the drift effect was not taken into account. Neutron flux and power density distribution were also addressed. The purpose of this paper is to review the aforementioned important safety parameters by doing the Monte Carlo code calculations. The results indicated that the core induces negative reactivity feedback due to temperature increase in fuel and moderator, but positive for temperature increase in the reflector. The temperature reactivity coefficient of fuel, moderator, and reflector exhibited −5.82×10−3 (%dk/k)/°C, −9.68×10−4 (%dk/k)/°C, and +1.84×10−4 (%dk/k)/°C, respectively. The introduction of void in the core either as a result of boiling or pump cavitation would induce positive reactivity of +0.115 (%dk/k)/(%void). Overall, the temperature reactivity coefficients exhibited large negative, and there is a comfortable margin between the operating temperature to the boiling point that might prevent void generation due to fuel boiling.

A Coupling is a device which is responsible for the operative power transmission between two shafts rotating at particular rpm. Coupling is used to connect two different shafts at their end and can slip or fail depending upon the torque limit. It is the crucial part of any power transmission and may last for very long time if designed and maintained properly. The present study of this paper is to reduce the stress that acting on the bolts by making it uniform strength coupling. The stress in the threaded part of the bolt will be higher than that in the shank. Hence a greater portion of the will be absorbed at the region of the threaded part which may fracture the threaded portion because of its small length. An axial hole is drilled at the center of the bolt through the head as far as thread portion such that the stress in the bolt is uniformly distributed along the length of the bolt. The present study of this paper is to reduce the maximum shear stress by selecting a suitable material for flange coupling. For this purpose, modelling of the rigid-flange coupling is carried out in Solidworks and analysed in ANSYS Workbench. Objective is to design a flanged coupling to connect the drive shaft of a 10 kW Kirloskar diesel generator operating at a rated speed of 1500 rpm to an alternator. The above specifications show a maximum torque transmission of 63.662 Nm. A standard shaft of ∅25 mm is used, and the analysis for basic rigid flange is done, including varying the materials. From the results obtained, the existing design is modified to reduce the weight and improve performance.

In the present paper, we have simulated the high performing SnS based solar cell by using SCAPS. SCAPS is one dimensional simulating software which is used for the simulation of solar cell. The solar cell consists of SnS based absorber layer, Zn (O, S): N buffer layer and ZnS as window layer. The p-SnS/Zn (O, S): N/ZnS is device structure of solar cell. The effect of absorber layer thickness and temperature on electrical parameter of solar cell have been reported in the present paper.

In this paper brake performance is studied under varying brake pressure. This brake pressure depends upon the pedal ratio. Along with theoretical analysis software like ANSYS is used to determine the sustainability of the disc under varying load that are obtained by varying force applied on pedal and pedal ratios. A brake is a mechanical device that hinders movement by retaining kinetic energy from a moving component. It is utilized for halting a moving vehicle, wheel, tire, disc or to keep its movement, regularly achieved by means of friction. The parts involved in the braking system are simple but the performance of these brakes greatly varies with slight variations involved in it. Though there are many factors that vary the performance of brakes initially the variations can be done at brake pedal level. The proper selection of the pedal ratio is important for the brake performance. This importance of this small part is the concept of this paper. The importance of this part is described and its effects are detailed in this paper.

Bioethanol is one of the new renewable energy alternatives that have the potential to be used as vehicle fuel by mixing a certain percentage of gasoline. However, the characteristic of this mixture has some differences from pure gasoline fuel. These differences may cause that the mixture fuel is not matched with the standard engine requirements. It will cause a reduction in the value of engine performance. All of these matters have brought us to research for optimizing engine performance that uses gasoline-ethanol fuel. In this paper, a study about ignition time is carried out as a solution for optimizing the performance. The purpose of this research is to optimize the engine performance through engine test using a dynamo testbed. We all know that the Engine Control Module (ECM) is a device to control some systems that run-in engine. One of the systems that controlled by ECM is ignition timing. In this paper, we change the degree for ignition time by expecting that these changes will have some effect on the result. The ignition time and the fuel mixture are the parameters for this research. As a result, we find that changing the ignition time become an advance mode will increase the engine performance and the specific fuel consumption. Keywords: Gasoline, Bioethanol, Engine Control Module, Engine Performance, and Ignition Time.

The paper reports on the results of experimental studies of the operation of the vortex ejector. In particular, different geometrical options for a vortex chamber of the ejector are studied. In order to carry out experimental research, six plastic models of the vortex chamber differing in their diameter have been made. The experimental results show that the most effective operation corresponds to the ratio of the diameters of the vortex and mixing chambers equal to dvc/dmc = 2. This provides the highest values of the ejection coefficient and the lowest values of the relative pressure at the passive nozzle. Both, increase and decrease in dvc/dmc leads to the reduction of these parameters and overall efficiency of the ejector.The paper reports on the results of experimental studies of the operation of the vortex ejector. In particular, different geometrical options for a vortex chamber of the ejector are studied. In order to carry out experimental research, six plastic models of the vortex chamber differing in their diameter have been made. The experimental results show that the most effective operation corresponds to the ratio of the diameters of the vortex and mixing chambers equal to dvc/dmc = 2. This provides the highest values of the ejection coefficient and the lowest values of the relative pressure at the passive nozzle. Both, increase and decrease in dvc/dmc leads to the reduction of these parameters and overall efficiency of the ejector.

The paper presents considerations regarding the process of determining the fuel consumption from diesel locomotive engines. In order to know the actual fuel consumption for a given engine, depending on the parameters of the drive system operation, it is necessary to carry out activities aimed at determining its operational indicators. This can be achieved by performing tests in real driving conditions or calculating fuel consumption using a calculation method based on the engine operating conditions. The paper presents the fuel consumption of a Stage II approved locomotive engine, which is used to drive various types of off-road machines and rail vehicles. The presented results of fuel consumption include the values determined on the resistor at set operating points and in real operating conditions. Using the assumptions of the vehicle’s operating time density characteristics, a computational method for assessing the fuel consumption of traction locomotives was developed. When comparing the results of bench and real measurements, the influence of the work parameters variability on fuel consumption was determined. In the summary, conclusions regarding the developed method were formulated, and reference was made to the possibility of using this tool to assess the ecological indicators of rail vehicles.

The paper discusses questions dedicated accumulation of graphite radioactive waste generated during commissioning of uranium-graphite nuclear reactor. Authors determine character of contamination of irradiated graphite by different radionuclides (especially 137Cs, 60Co, 90Sr) using autoradiographic methods and by means of electron microscope (scanning electron microscope – analysis). It has been obtained images of polished section of irradiated graphite in back-scattered electrons. Authors suggest the method of thermal decontamination of irradiated graphite surface by noble gas flow for the purpose of potential hazard reduction of graphite radioactive waste. The developed mathematical model of thermal decontamination of irradiated graphite subject to Wigner energy release under radiation defect annealing has been demonstrated in paper. The article represents laws reflecting dependence of recession velocity of radioactive contamination of graphite radioactive waste and different parameters of process subject to Wigner energy release.The paper discusses questions dedicated accumulation of graphite radioactive waste generated during commissioning of uranium-graphite nuclear reactor. Authors determine character of contamination of irradiated graphite by different radionuclides (especially 137Cs, 60Co, 90Sr) using autoradiographic methods and by means of electron microscope (scanning electron microscope – analysis). It has been obtained images of polished section of irradiated graphite in back-scattered electrons. Authors suggest the method of thermal decontamination of irradiated graphite surface by noble gas flow for the purpose of potential hazard reduction of graphite radioactive waste. The developed mathematical model of thermal decontamination of irradiated graphite subject to Wigner energy release under radiation defect annealing has been demonstrated in paper. The article represents laws reflecting dependence of recession velocity of radioactive contamination of graphite radioactive waste and different parameters of process subje...

This paper describes the probabilistic nonlinear analysis of the hermetic steel door of the reactor shaft failure due to extreme pressure and temperature. The scenario of the hard accident in nuclear power plant (NPP) and the methodology of the calculation of the fragility curve of the failure overpressure using the probabilistic safety assessment PSA 2 level is presented. The model and resistance uncertainties were taken into account in the response surface method (RSM).This paper describes the probabilistic nonlinear analysis of the hermetic steel door of the reactor shaft failure due to extreme pressure and temperature. The scenario of the hard accident in nuclear power plant (NPP) and the methodology of the calculation of the fragility curve of the failure overpressure using the probabilistic safety assessment PSA 2 level is presented. The model and resistance uncertainties were taken into account in the response surface method (RSM).

Because the winding resistance of small power transformer is far bigger than the inductance of winding, it is difficult to obtain the leakage inductance parameters of small power transformer winding accurately by traditional experimental methods. In order to solve the above problems, this paper proposes a method of obtaining leakage inductance by applying step voltage, establishes the T-type equivalent circuit model of transformer, carries out the measurement experiment of leakage inductance, and carries out Simulink simulation with the parameters obtained by applying step voltage. The results show that the simulation results are in good agreement with the experimental results, which verifies the validity of the method.Because the winding resistance of small power transformer is far bigger than the inductance of winding, it is difficult to obtain the leakage inductance parameters of small power transformer winding accurately by traditional experimental methods. In order to solve the above problems, this paper proposes a method of obtaining leakage inductance by applying step voltage, establishes the T-type equivalent circuit model of transformer, carries out the measurement experiment of leakage inductance, and carries out Simulink simulation with the parameters obtained by applying step voltage. The results show that the simulation results are in good agreement with the experimental results, which verifies the validity of the method.

The KDamper is a novel passive vibration absorption concept, based essentially on the optimal combination of appropriate stiffness elements, which include a negative stiffness element. In this paper, the implementation of the KDamper as a seismic Absorption Base (KDAB) is considered. The paper proceeds to the assessment of the performance of the KDamper as seismic absorption base in a typical flexible 5-storey concrete building structure with a fundamental period of 0.5 sec. The structure is excited by artificial accelerograms, generated to be compatible with the highly demanding Eurocode 8 case C with a PGA of 0.36g, and by real earthquake records. The performance of the KDAB is compared not only to the original structure but also to the cases of conventional and highly damped base isolation systems, as well as the case of a Tuned Inerter Damper (TID). Alternative options for the selection of the KDamper natural frequency are considered, leading to two limit cases. In the first case, the nominal KDamper frequency is selected equal to the low frequency of a conventional base isolation system, resulting in a drastic improvement of the overall structural performance. However, another interesting option is revealed, which foresees the implementation of the KDAB with a nominal frequency much higher than that of the base isolation system. This choice leads to a drastic reduction of the relative base displacement, in the order of few centimeters, combined with acceptable structural performance with respect to drift and absolute acceleration. As a consequence, the KDamper can be implemented as “stiff seismic absorption base”, overcoming the disadvantages of the conventional base isolation systems, and thus leading towards alternative seismic protection technologies.

This paper presents a preliminary study on the efficacy of using induction infrared thermography (IIRT), also known as pulsed eddy current thermography (PECT), to detect sensitized metal in welded 440C stainless steel. It is well-known that sensitization alters a specimen’s microstructural geometry (e.g. presence of precipitates at grain boundaries) and its physical properties (e.g. conductivity differences between precipitates and parent material). The proposed underlying physics is that sensitized metal will conduct induced currents differently than healthy metal, producing an altered heat signature from propagating induced currents that is observable using infrared thermography (IRT). In this paper, we first present an experimental study to demonstrate the feasibility of the method. Experimentally, we introduce sensitization to 440C plate specimens through welding and then conduct IIRT testing using a commercial induction coil and a FLIR SC8200 infrared camera. Next, we present a computational study to explain the physical process underlying the IIRT testing and compare it with the experimental results. Specifically, we present a thermo-electromagnetic model, including the heat equation and the Maxwell-Faraday equation for predicting the electromagnetic field caused by a sinusoidal excitation current through the induction coil. We introduce an empirical model to relate the degree of sensitization to the local increase in induced current density. The model equations are solved using COMSOL Multiphysics 5.3a and the results are compared with the experimental data.

The paper focuses on the mechanical response of short and long fibre composites on impact and analyses the differences of individual types of fibres on vibration, damping, modal properties analysis inside a material structure. The paper provides the analytical determination of the impact force. The impact testing is carried out by specially designed testing stand accompanied by contactless laser vibrometer to substitute the need of bump hammer and accelerometers. The measuring stand is designed to be universal for various composite materials and different shapes and dimensions. The paper provides the analysis of the measured results of focusing on damping properties carbon and glass fibres composites and their different material configurations, as well as conventional and nonconventional materials.

The proper application of multi-material design is an effective way of saving energy costs and reducing CO2-emissions. In the production of heavy-duty components, the tailored forming technology offers the possibility of bringing the right material to the right place. In this context, this paper deals with the challenges that arise during compound forging such components using the example of a bi-metal bearing bushing. For this purpose, steel is placed into the highly stressed bearing surface, where high performance characteristics are required, while the rest of the part is made of aluminium to reduce the total weight of the component. Due to the different material properties of steel and aluminium, the process design for bi-metal compound forging is very demanding and requires process-specific heating and forming strategies, which are presented and discussed in this paper. After the implementation, forging experiments were carried out and the bearing bushings obtained were evaluated by metallurgical and mechanical tests. A crucial aspect in assessing the quality of such components is the bond strength, which generally depends on the development of intermetallic phases. Therefore, an analysis of the joint and phase formation in the area of the joining zone of the compound forged parts was performed initially using optical microscopy. The metallurgical studies showed good bonding with form- and force-closed joint and insular intermetallic phases along the joining zone. Afterwards, the bond strength was determined by push-out tests, whose results were finally correlated with the metallurgical findings.

Rotating Supersonic Combustion Engine (RSCE) has the benefit of high-frequency operation, high thrust density for future generation engine. However, RSCE that is developed is still at infancy stage which requires further refined study especially in determining best mixing scheme. Therefore, the objective of this study is to develop and to test the new mixing scheme of RSCE using swirl injection system. The research also involves the investigation of the RSCE engine using supersonic combustion ignition system with various fuel-air injection configurations on the overall engine performance. This paper discussed about the engine and its ignition development using various configuration of swirl air-fuel injection system to achieve successful operation of rotating supersonic combustion engine.Rotating Supersonic Combustion Engine (RSCE) has the benefit of high-frequency operation, high thrust density for future generation engine. However, RSCE that is developed is still at infancy stage which requires further refined study especially in determining best mixing scheme. Therefore, the objective of this study is to develop and to test the new mixing scheme of RSCE using swirl injection system. The research also involves the investigation of the RSCE engine using supersonic combustion ignition system with various fuel-air injection configurations on the overall engine performance. This paper discussed about the engine and its ignition development using various configuration of swirl air-fuel injection system to achieve successful operation of rotating supersonic combustion engine.

The U.S. National Nuclear Security Administration Material Management and Minimization (M3) program is enabling the transformation of research and test reactors to Low Enriched Uranium (LEU) fuels using reactor safety analysis and new fuel designs. The M3 program has developed LEU based alternative fuels that will enable reactors to continue their missions while operating safely and cost effectively. A salient performance factor of the fuel plate is the bond strength of the fuel foil (including the Zr interlayer) to the Al substrate. The laser shock technique will be used to provide interface strength feedback for fabrication process development and to understand the effects of reactor irradiation. This paper focuses on modifying a laser shock system built for laboratory use. The resulting system designed for installation in a nuclear hot cell uses only optical fibers without polarization elements as the salient delivery and collection of signal light. The laser shock (LS) system based on fiber optics is more practical for the rigors and remote operation requirements in a nuclear hot cell. This paper will also discuss the bond strength results from round robin testing obtained in the laboratory comparing the LS laboratory and hot cell systems.

Blades on the wind turbine are moving due to the lift and drag force. During the conversion process of wind energy into electrical energy arise energy loss naturally. One of the optimization techniques of power harvesting in wind turbine is pitch angle control on the turbine blades hence, the wind turbine power output lies on optimum condition. The wind turbine control system in this paper is composed of turbine blades, servo motor as actuator, rotational connector and rotary encoder as transmitter. The best result of wind turbine prototype test shows that Power Coefficient (CP) up to 0.57510. To obtain adaptive control conform to the existing wind speed, pitch angle adjustment is controlled using PID control, with each parameters value of Kp, Ki, and Kd are equal to 0,0239069, 0.0001382, 0,053518, respectively. The parameters value are achieved by implementing PSO optimization method. According to the result of the test, the set points are 40, 60, 80 and 100 rpm, which is the system is able to reach the set point with maximum overshoot attains 26.25% and the rise time in 181 seconds. Therefore, the PID-PSO produces a better response than uncontrolled and fuzzy-based controller.Blades on the wind turbine are moving due to the lift and drag force. During the conversion process of wind energy into electrical energy arise energy loss naturally. One of the optimization techniques of power harvesting in wind turbine is pitch angle control on the turbine blades hence, the wind turbine power output lies on optimum condition. The wind turbine control system in this paper is composed of turbine blades, servo motor as actuator, rotational connector and rotary encoder as transmitter. The best result of wind turbine prototype test shows that Power Coefficient (CP) up to 0.57510. To obtain adaptive control conform to the existing wind speed, pitch angle adjustment is controlled using PID control, with each parameters value of Kp, Ki, and Kd are equal to 0,0239069, 0.0001382, 0,053518, respectively. The parameters value are achieved by implementing PSO optimization method. According to the result of the test, the set points are 40, 60, 80 and 100 rpm, which is the system is able to reach the ...

This paper constructed a new high speed and power density servo motor design scheme based on magnetic pole eccentricity proposed according to the requirements of electrical performance parameters. The analytical formulae were deduced in view of the theory of thick-walled elastic cylinders and the actual model by analytical calculations and finite element calculations. The structure strength of permanent magnet was analyzed. Furthermore, comprehensively comparing and analyzing the calculation results of the two methods verify the accuracy of the analytical calculation method and the rationality of the permanent magnet structure design. In brief, this paper provides a reference for the design of high-speed motor magnetic pole eccentricity.

The pulsed plasma thruster (PPT) is a potential electric thruster for microsatellites. One important content of PPT performance research is the measurement of micro-thrust and micro-impulse. This paper summarizes the 4 typical dynamic measuring systems at home and abroad, which include the single pendulum type, the torsion pendulum type, the cantilever type and the balance type. In the paper, the structure principle, measurement performance, advantages and disadvantages of various configurations are compared and analyzed. The development process of each micro-thrust and micro-impulse measurement technology is summarized, and its developing trend is prospected.

Newly developed 3D reconstruction technology has many uses ranging from facial recognition, self-driving vehicles, and producing accurate models of samples. To utilize 3D reconstruction, a depth map of the sample must be generated from a series of images. This can be done using stereoscopic 3D, or in the case of a fixed camera (such as the 10ID On-Axis Microscope at NSLS-II used for this paper) through focus stacking. This paper will explain how focus stacking can be used to generate in-focus images at very shallow depth of fields, and merge these images to create depth maps and 3D models.

There are two thermodynamic models of the closed and vented heat pump drying process described in the paper. The models have been used for optimization of process design parameters with respect to drying rate and energy efficiency, respectively. The optimization was performed in points of parametric space defined by refrigerant and air flow rates. Results of the optimization shows the same maximal drying rate performance for closed cycle and both objective functions. There is higher potential of drying time reduction for vented cycle in comparison to closed cycle.There are two thermodynamic models of the closed and vented heat pump drying process described in the paper. The models have been used for optimization of process design parameters with respect to drying rate and energy efficiency, respectively. The optimization was performed in points of parametric space defined by refrigerant and air flow rates. Results of the optimization shows the same maximal drying rate performance for closed cycle and both objective functions. There is higher potential of drying time reduction for vented cycle in comparison to closed cycle.

Anatomical structures and microstructures of tropical bamboo species were studied. Harvested three-year- old Gigantochloa scortechinii prepared for this study. Electron Microscopy (EM) especially Scanning Electron Microscope (SEM) and Transmission Electron Microscope (TEM) are efficient tools for microstructure viewing. This paper focused on the vascular bundles, fibers and parenchyma cells located at the internodes and nodes at the outer, middle and inner sections of natural and preservatives treated bamboos. The result of this study highlighted that the bamboo species exhibit similarity in their characteristics, but the anatomical features and microstructure were different. This paper also describes the differences in the micrographs taken using SEM and TEM.Anatomical structures and microstructures of tropical bamboo species were studied. Harvested three-year- old Gigantochloa scortechinii prepared for this study. Electron Microscopy (EM) especially Scanning Electron Microscope (SEM) and Transmission Electron Microscope (TEM) are efficient tools for microstructure viewing. This paper focused on the vascular bundles, fibers and parenchyma cells located at the internodes and nodes at the outer, middle and inner sections of natural and preservatives treated bamboos. The result of this study highlighted that the bamboo species exhibit similarity in their characteristics, but the anatomical features and microstructure were different. This paper also describes the differences in the micrographs taken using SEM and TEM.

One of the vital components for the pebble reactor is the fuel handling system which was employed to load, recirculate and discharge the depleted fuel during the operation of reactor. The previous fuel handling design and experience of the High Temperature Reaktor 10 MWth (HTR-10) and HTR-PM were beneficial for the development of High Temperature Gas-cooled Reaktor (HTGR) in Indonesia such as for the Reaktor Daya Eksperiment (RDE) 10 MWth and PELUIT 150 MWth. One of the focus for the development especially for the control is an important factor to ensure that the reliability and the safety during operation were guarantee. Therefore, aims of this paper is to understand and develop the automatic control system of the fuel handling. The development was done by applying the logic flowchart of the fuel handling HTGR with the HTR-10 as the reference. Some modification was made considering the future application in Indonesia It was demonstrated that the automation systems with Programmable Logic Controller (PLC) can control handling systems easily because each valve can be drive to open and close immediately as requested from the sensor. It was also demostrated that the timing chart monitoring confirms the control of flowchart process description for the new fresh fuel loading.One of the vital components for the pebble reactor is the fuel handling system which was employed to load, recirculate and discharge the depleted fuel during the operation of reactor. The previous fuel handling design and experience of the High Temperature Reaktor 10 MWth (HTR-10) and HTR-PM were beneficial for the development of High Temperature Gas-cooled Reaktor (HTGR) in Indonesia such as for the Reaktor Daya Eksperiment (RDE) 10 MWth and PELUIT 150 MWth. One of the focus for the development especially for the control is an important factor to ensure that the reliability and the safety during operation were guarantee. Therefore, aims of this paper is to understand and develop the automatic control system of the fuel handling. The development was done by applying the logic flowchart of the fuel handling HTGR with the HTR-10 as the reference. Some modification was made considering the future application in Indonesia It was demonstrated that the automation systems with Programmable Logic Controller (PLC)...

The use of Natural Gas (NG) in internal combustion engines has been increased in this decade. The objective of this paper is to investigate the NG injection timing on the dual-fuel engine. In this paper experimental based on dual fuel engine strategy (DFE strategy) was tested with several variations of gas injection based on CA at the modified direct - injection engine into a DFE strategy. In the data test, the variation is CA 260, 244, 230, 214 bTDC. This research is for observed how it affects the engine performance. The indication of the effect of NG injection based on the CA variation is the non-homogenization of the NG-air mixture in the intake manifold, and the delay in mixing NG-air to go into the combustion chamber. From several data tests that have been done, there is an increase in engine power, thermal efficiency and a decrease in SFOC fuel consumption. The optimum combination of the DFE strategy has a fluctuating value when taken from test experimental data. The trend is seen, that CA 230 bTDC is the optimum value to be operated in the DFE strategy. Because there is an increase in Torque, Efficiency thermal, and a decrease in SFOC of fuel consumption.

Selective laser melting is a new manufacturing technique that can easily facilitates metal parts with complex structural shapes and high performance. This paper processed 316L stainless steel by SLM technology, and characterized the microstructure and mechanical properties of the as-built specimen. The complex microstructure with cells and columnar grains was observed in the specimen, the specimen density is about 97% and the hardness can reach 189 HV. The wear test results show that the average friction coefficient of the SLM sample is 0.642.Selective laser melting is a new manufacturing technique that can easily facilitates metal parts with complex structural shapes and high performance. This paper processed 316L stainless steel by SLM technology, and characterized the microstructure and mechanical properties of the as-built specimen. The complex microstructure with cells and columnar grains was observed in the specimen, the specimen density is about 97% and the hardness can reach 189 HV. The wear test results show that the average friction coefficient of the SLM sample is 0.642.

Printhead with microscale nozzle is very important for electrohydrodynamic jet (E-jet) printing, that decides output performance of system. It is challenge and necessary to design and fabricate a protruding Si-based nozzle strucure for E-jet prining. In this paper, a protruding Si-based nozzle structure is designed and the corresponding fabricating flow chart is introduced based on photolithography, wet etching, magnetron sputtering, inductively coupled plasma. Then, the effect of etching ratio between big area and small section is analyzed and discussed in details. The failure in first time fabrication shows that it is indipensable to not only achieve the process parameters, but also design a set of reasonable fabricating flow chart for manufacturing a Si-baesd nozzle structure sucessfully. Finally, a protruding Si-based nozzle structue is successfully fabricated for E-jet printing.Printhead with microscale nozzle is very important for electrohydrodynamic jet (E-jet) printing, that decides output performance of system. It is challenge and necessary to design and fabricate a protruding Si-based nozzle strucure for E-jet prining. In this paper, a protruding Si-based nozzle structure is designed and the corresponding fabricating flow chart is introduced based on photolithography, wet etching, magnetron sputtering, inductively coupled plasma. Then, the effect of etching ratio between big area and small section is analyzed and discussed in details. The failure in first time fabrication shows that it is indipensable to not only achieve the process parameters, but also design a set of reasonable fabricating flow chart for manufacturing a Si-baesd nozzle structure sucessfully. Finally, a protruding Si-based nozzle structue is successfully fabricated for E-jet printing.

Most of the metal quinolate have broad excitation spectra is in range 385nm to 410 nm with emission spectra in the blue green region and hence can be easily pumped by the UV and near UV LEDS. However the emission efficiency is significantly low to make them suitable for any practical applications. Blending quinolates with polymers not only make them highly emissive but the emission and excitation can be tailored according to the requirement. Moreover the properties changes with the way in which blend is prepared, which are labeled as In-situ blending and Ex-situ blending. In In-situ blending the Mgq2 is prepared in the polymer solution itself whereas in Ex-situ blending the previously prepared Mgq2 powder is dissolved in suitable solvent and mixed with the polymer. In this paper we report photoluminescence properties of Mgq2 and its composite film with PVOH. Green Yellow emission in Mgq2 powder is observed when excited by 385 nm LED whereas intense green emission is observed when excited by 400 nm LED. An Intense emission is observed in Mgq2 Ex-situ composites and observed emission is 7 times more with respect to powder. The Ex-situ composite shows near white emission when excited by 385 nm LED whereas blue green emission is observed when excited by 400 nm LED. In In-situ composites near white emission is observed when excited by 385 nm whereas blue emission is observed when excited by 400 nm LED. Thus these blended polymers may find application as white light phosphor for PCLED applications using near UV LEDs.Most of the metal quinolate have broad excitation spectra is in range 385nm to 410 nm with emission spectra in the blue green region and hence can be easily pumped by the UV and near UV LEDS. However the emission efficiency is significantly low to make them suitable for any practical applications. Blending quinolates with polymers not only make them highly emissive but the emission and excitation can be tailored according to the requirement. Moreover the properties changes with the way in which blend is prepared, which are labeled as In-situ blending and Ex-situ blending. In In-situ blending the Mgq2 is prepared in the polymer solution itself whereas in Ex-situ blending the previously prepared Mgq2 powder is dissolved in suitable solvent and mixed with the polymer. In this paper we report photoluminescence properties of Mgq2 and its composite film with PVOH. Green Yellow emission in Mgq2 powder is observed when excited by 385 nm LED whereas intense green emission is observed when excited by 400 nm LED. An...