Search

The commercial telecommunication system in future would explore the electromagnetic spectrum with higher frequency than used now, because it requires higher speed of transmission data. Using the millimeter waves (mmW) with frequency ranging from 30 to 300 GHz, such requirement could be fulfilled. The upcoming 5G cellular technology is expected to use frequency 30 GHz or higher. Then materials with a specific characteristic at the mmW range are interesting to be explored and investigated. Here, we report the synthesis process of graphene/TiO2 deposited on paper and their transmission characteristics to the electromagnetic energy at frequency 27-40 GHz (Ka-Band). The reduced graphene oxide (rGO) was synthesized by a modified Hummers method with introduction of microwave irradiation in the process. rGO and TiO2 were mixed in ethanol solution and deposited on the paper by a spraying technique. Transmission coefficient of electromagnetic wave energy at Ka-Band was measured by using the millimeter vector networ...

On-line measurement of material properties is a goal of many manufactures for production improvement and quality control. In the paper industry, the elastic stiffness of the paper web needs to be accurately measured and controlled online. Currently, contact ultrasonic methods are employed to measure the elastic constants of paper offline. Piezoelectric transducers are placed in contact with the paper surface to generate and detect plate wave modes, known as Lamb wave modes, in the paper in both the machine and cross directions. Laser ultrasonics offers a new approach to making elastic wave measurements that does not require contacting the paper web. A pulsed laser generates ultrasound in the paper by delivering a high intensity short impulse to the paper through thermoelastic expansion. An optical interferometer is used to demodulate the small phase modulation that the elastic wave produces on a continuous probe laser beam. Difficulty in applying this approach to online measurements of rapidly moving pape...

Water filter has been made to improve well water quality by using filtration concept in which activated carbon from cocoa rind waste and clay was used. The filter was made by varying the composition of cocoa rind waste and clay in activated carbon at the ratios of 85%:15%, 80%:20%, 75%:25%, 70%:30% and 65%:35%. The combustion temperature was varied at 200°C, 230°C, 260°C, 290°C and 320°C. Then it was molded by using mold and press conventional technique. The characterization results showed optimum composition was reached at 65%:35% ratios under 320°C combustion where the absorbance and porosity of water filter were at 86% and 52.38% respectively. Whereas density of 0.617 g/cm3 and 0.00514 MPa compressive strength were obtained from 85%:15% composition at 200°C combustion temperature. The performance test for the filter in purifying well water gave 3.2 NTU for turbidity, 7 TCU for color, 338 µS/cm conductivity, 6.7 pH level and Fe content of 1.0 mg/L. The analysis done showed that the water filtered has met the standard quality of clean water.

The paper focuses on the development of a low-cost biogas filtration system for alternating current generator to achieve higher efficiency in terms of power production. A raw biogas energy comprises of 57% combustible element and 43% non-combustible elements containing carbon dioxide (36%), water vapor (5%), hydrogen sulfide (0.5%), nitrogen (1%), oxygen (0 – 2%), and ammonia (0 – 1%). The filtration system composes of six stages: stage 1 is the water scrubber filter intended to remove the carbon dioxide and traces of hydrogen sulfide; stage 2 is the silica gel filter intended to reduce the water vapor; stage 3 is the iron sponge filter intended to remove the remaining hydrogen sulfide; stage 4 is the sodium hydroxide solution filter intended to remove the elemental sulfur formed during the interaction of the hydrogen sulfide and the iron sponge and for further removal of carbon dioxide; stage 5 is the silica gel filter intended to further eliminate the water vapor gained in stage 4; and, stage 6 is the activated carbon filter intended to remove the carbon dioxide. The filtration system was able to lower the non-combustible elements by 72% and thus, increasing the combustible element by 54.38%. The unfiltered biogas is capable of generating 16.3 kW while the filtered biogas is capable of generating 18.6 kW. The increased in methane concentration resulted to 14.11% increase in the power output. The outcome resulted to better engine performance in the generation of electricity.

Scarcity in fuel from fossil fuel has led to exploration of potential substitutes from renewable sources. Biodiesel as one of renewable energy sources is identified as cleaner alternative to petroleum fuel. This paper reports on the study of potassium carbonate, K2CO3 sourced from pineapple and orange peels as heterogeneous catalyst for biodiesel production. K2CO3 was produced by drying of fruit peel prior to calcination at temperature ranged from 700°C to 1000°C for 2 to 4 hours. To determine the physicochemical properties of the resulting ash, Fourier transform infrared (FTIR) and Scanning electron microscopy (SEM) analysis were employed for the characterization of the solid. Through FTIR analysis, the presence of carbonate was confirmed while SEM analysis revealed the morphological properties of the catalyst. Biodiesel with highest yield of 95.6% was produced at 60°C, 2.75 wt% of catalyst and 12:1 molar ratio of methanol to oil.

The presence of lead heavy metals in waters can cause negative impacts on the environment. One way to reduce lead metal content is by adsorption process using waste of banana leaf. Adsorption of lead metal using banana leaf waste has been successfully done. This study aims to determine the optimum contact time so as to produce the greatest adsorption power to lead metal in banana leaf waste, and determine the adsorption kinetics. Determination of functional groups was performed by using infrared spectroscopy while the determination of lead content using atomic absorption spectroscopy. The adsorption process is done by batch system that is soaking bio sorbent in solution containing lead. The immersion times were varied at 0, 30, 60, and 120 minutes. The adsorption process is carried out by mixing 25 mL of Pb(NO3)2 solution with 0.125 gram of activated banana leaf waste. Determination of amount of lead metal adsorbed by banana leaf waste done by calculating the difference of initial metal concentration with concentration in filtrate. Based on result of research known that optimum adsorption time from waste of activated banana leaf is for 30 minutes. The adsorption capacity of activated banana leaf waste in the time was 35.714%. Adsorption kinetics of lead at banana leaf follows kinetic model of pseudo two Ho with the value of R2 0.924 and the value of k is 13.305 minutes−1.

The nitrogen compound concentration in water is increased by atmospheric-pressure plasma discharge treatment. A rod-to-water electrode discharge treatment system using plasma discharge has been developed by our group to obtain water with a high concentration of nitrogen compounds, and this plasma-treated water improves the growth of chrysanthemum roots. However, it is difficult to apply the system to the agriculture because the amount of treated water obtained by using the system too small. In this study, a multi-spark discharge system (MSDS) equipped multiple spark plugs is presented to obtain a large amount of plasma-treated water. The MSDS consisted of inexpensive parts in order to reduce the system introduction cost for agriculture. To suppress the temperature increase of the spark plugs, the 9 spark plugs were divided into 3 groups, which were discharged in order. The plasma-treated water with a NO3− concentration of 50 mg/L was prepared using the MSDS for 90 min, and the treatment efficiency was about 6 times higher than that of our previous system. It was confirmed that the NO2−, O3, and H2O2 concentrations in the water were also increased by treating the water using the MSDS.The nitrogen compound concentration in water is increased by atmospheric-pressure plasma discharge treatment. A rod-to-water electrode discharge treatment system using plasma discharge has been developed by our group to obtain water with a high concentration of nitrogen compounds, and this plasma-treated water improves the growth of chrysanthemum roots. However, it is difficult to apply the system to the agriculture because the amount of treated water obtained by using the system too small. In this study, a multi-spark discharge system (MSDS) equipped multiple spark plugs is presented to obtain a large amount of plasma-treated water. The MSDS consisted of inexpensive parts in order to reduce the system introduction cost for agriculture. To suppress the temperature increase of the spark plugs, the 9 spark plugs were divided into 3 groups, which were discharged in order. The plasma-treated water with a NO3− concentration of 50 mg/L was prepared using the MSDS for 90 min, and the treatment efficiency was abo...

The technological development of concrete demands innovation regarding the alternative material as a part of the effort in improving quality and minimizing reliance on currently used raw materials such as bottom ash of palm oil. Bottom ash known as domestic waste stemming from palm oil cultivation in East Kalimantan contains silica. Like cement in texture and size, bottom ash can be mixed with concrete in which the silica in concrete could help increase the compressive strength of concrete. This research was conducted by comparing between normal concrete and concrete containing bottom ash as which the materials were apart of cement replacement. The bottom ash used in this research had to pass sieve size (#200). The composition tested in this research involved ratio between cement and bottom ash with the following percentages: 100%: 0%, 90%: 10%, 85%: 15% and 80%: 20%. Planned to be within the same amount of compressive strength (fc 25 MPa), the compressive strength of concrete was tested at the age of 7, ...

In this study has been the treatment of batik waste using distillation method. This study aims to the treatment of batik waste using distillation method. Batik is a world heritage that has an impact on economic improvement and environmental damage. Batik waste is a hazardous and toxic waste material. Batik waste in this research has been taken from Batik Industry in Yogyakarta, Indonesia. Batik waste of 5 L is included in the distillation apparatus, then the distillation run for 4 hours. The distillation product of solids and liquids is collected and analyzed. The solid produced at the distillation boiler was analyzed by FTIR. The distillation liquid was analyzed ammonia and COD concentration using UV-Vis Spectrophotometer. The result of the analysis showed that based on FTIR spectra obtained by dye with high purity. The analysis results shown are of ammonia, COD and pH were 0.652 mg/L, 238.31 mg/L, and 7.306, respectively. The compounds produced by boiler are the azo dye based on the spectrum at wave numbers 1554.07 cm−1. The conclusion of this research is that the distillation method is very suitable for the treatment of the batik waste at small batik industry. Advantages of distillation techniques that can be obtained two products are water and dye that can be used in batik industry.

Geopolymer is an environmentally attractive Portland cement substitute, owing to its lower carbon footprint and its ability to consume various aluminosilicate waste materials as its precursors. This work describes the development of geopolymer formulation based on biomass-coal ash blends, which is predicted to be the prevalent type of waste when biomass-based thermal energy production becomes mainstream in Indonesia. The ash blends contain an ASTM Class F coal fly ash (FA), rice husk ash (RHA), and coconut shell ash (CSA). A mixture of Na2SiO3 and concentrated KOH is used as the activator solution. A preliminary experiment identified the appropriate activator/ash mass ratio to be 2.0, while the activator Na2SiO3/KOH ratio varies from 0.8 to 2.0 with increasing ash blend Si/Al ratio. Both non-blended FA and CSA are able to produce geopolymer mortars with 7-day compressive strength exceeding the Indonesian national SNI 15-2049-2004 standard minimum value of 2.0 MPa stipulated for Portland cement mortars. As...

An experimental study on co-pyrolysis of coal with biomass wastes to produce hybrid coal was conducted to investigate the effects of important process variables, namely biomass type (rice husk and sawdust), blend composition, and co-pyrolysis temperature on the quality of hybrid coal. The experiments were carried out using a vertical tubular furnace equipped with temperature controller to maintain the co-pyrolysis reactor at a given temperature. Nitrogen gas was introduced into the furnace to create an inert environment preventing the sample from burning. A known mass of solid sample consisting of manually granulated blend of coal and biomass with binder in spherical shape was contained in a basket made of stainless sieve. After a given residence time, the sample was taken from the furnace. The blend sample prior to experiment and the produced hybrid coal were then characterized for its proximate analysis, ultimate analysis and calorific value. Experimental findings suggested that by increasing co-pyrolys...

Iron and Manganese was examined from riverbank filtration (RBF) and river water in Sungai Kerian, Lubok Buntar, Serdang Kedah. Water from the RBF was influenced by geochemical and hydro chemical processes in the aquifer that made concentrations of iron (Fe), and manganese (Mn) high, and exceeded the standard values set by the Malaysia Ministry of Health. Therefore, in order to overcome the problem, the artificial barrier was proposed to improve the performance of the RBF. In this study, the capability and performance of granular activated carbon, zeolite and sand were investigated in this research. The effects of dosage, shaking speed, pH and contact time on removal of iron and manganese were studied to determine the best performance. For the removal of iron using granular activated carbon (GAC) and zeolite, the optimum contact time was at 2 hours with 200rpm shaking speed with 5g and 10g at pH 5 with percentage removal of iron was 87.81% and 83.20% respectively. The removal of manganese and zeolite arose sharply in 75 minutes with 90.21% removal, with 100rpm shaking speed. The GAC gave the best performance with 99.39% removal of manganese. The highest removal of manganese was achieved when the adsorbent dosage increased to 10g with shaking speed of 200rpm.

Depletion of petroleum and environmental problem have led to look for an alternative fuel sources In many ways, biomass is a potential renewable source. Among the many forms of biomass, oil palm empty fruit bunch (EFB) is a very attractive feedstock due to its abudance, low price and non-competitiveness with the food chain. EFB can be converted bio-oil by pyrolysis process. but this product can not be used directly as a transportation fuel, so it needs upgrading bio-oil through a catalytic cracking process. The catalyst plays an important role in the catalytic cracking process. The objective of this research is to study the effect of Ni concentrations (1,3,5 and 7 wt.%) on the characteristics of the catalyst Ni / Silica-Alumina and the performance test for the catalytic cracking of bio-oil. Preparation of the catalyst Ni / Silica-Alumina was done by impregnation at 80°C for 3 hours, then done to calcination and reduction at 500°C for 2 hours. The performance test was conducted on catalytic cracking temper...

In this work, graphene was exfoliated by introducing the constant Galvano Static Current (GSC) at the range of 300-600mA with the incremental of 100mA. The Graphene produced through this exfoliation technique was also investigated through optical characterization using Field Emission Scanning Electron Microscope (FESEM), Ultraviolet Visible (UV-vis) spectroscopy and Raman spectroscopy to comprehend the quality behavior. To further understand the graphene characteristic, we applied the produced graphene on top of fabricated interdigitated electrode (IDE) device to investigate the electrical reaction.

A novel method of creating new lightweight aluminum-metallic composite materials in halide melts at temperatures of 973–1073 К in air atmosphere is proposed. The method for synthesizing aluminum-based metallic composite materials containing up to 2 wt. % graphene sheets uniformly distributed in a metal matrix is entirely new, having no analogies in current science and practice. The synthesis of graphene nanosheets in a metal matrix is a one-step simultaneous process taking place directly in molten aluminum in alkali halide melt without the necessity of a separate stage of synthesis and introduction of graphene. This has the potential to facilitate the inexpensive synthesis of aluminum-graphene composites with a high concentration of graphene. Aluminum-graphene composites formed according to this method are characterized by a high uniformity of graphene films with linear dimensions from 100 nm to 50 µm and a thickness from 1 nm to 3 nm in the metal bulk. No aluminum carbide forms under synthesis; aluminum-graphene and aluminum-graphite composites are resistant to corrosion in a NaCl solution. The hardness, strength and ductility of aluminum-graphene composites are at least 2–3 times as high as the initial aluminum material, proportional to the concentration of graphene.

Graphene has attracted a tremendous attention in recent years due to its unique properties such as mechanical, thermal, optical and electrical properties. However, a large scale production of this material is still an issue and subjected to intense research efforts. Here, we show a simple and green approach of the graphene synthesis from graphene oxide using ascorbic acid as reduction agent. A facile synthesis of graphene (rGO) through chemical oxidation of graphite into graphene oxide (GO) was described using modified Hummers method (Improved Tour Method/ITM). The ITM method does not produce toxic gas and the temperature of the oxidation is easily controlled using ice bath. The synthesized of graphene oxide was highly soluble and stable in water. The reduction of graphene oxide into graphene was performed using ascorbic acid (AA) in mild condition. The combined ITM method and green reduction using ascorbic acid open the avenue of replacing hydrazine in the reduction of graphite oxide into graphene and ma...

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.

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 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.

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.

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.

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 advent of Automated Fiber Placement (AFP) systems have aided the rapid manufacturing of composite aerospace structures. One of the challenges that AFP systems bring is the variability of the deposited prepreg tape layers, which are prone to gaps, overlaps and twists. The current detection method used in industry involves halting fabrication and performing a time consuming visual inspection of each tape layer. Typical AFP systems use a quartz lamp to heat the base layer to make the surface tacky as it deposits another tape layer. The innovation discussed in this paper is to use the preheated base layer as a through transmission heat source and inspect the newly added tape layer in situ using a thermographic camera mounted onto the AFP structure. Such a system would not only increase manufacturing throughput by reducing inspection times, but would also aid in process development for new structural designs or material systems. To this end, a small thermal camera was mounted onto an AFP robotic research platform at NASA, and thermal data was collected during typical and experimental layup operations. The data was post processed to reveal defects such as tow overlap/gap, wrinkling, and peel-up. Defects that would have been impossible to detect visually were also revealed in the data, such as poor/loss of adhesion between plies and the effects of vacuum debulking. This paper will cover the results of our experiments, and the recent progress on the data reduction algorithms in preparation for machine learning development.

Operator support systems are extensively studied and developed to support human operators for their activities in especially an abnormal condition of a nuclear power plant. By the advancement of computer technology and artificial intelligence, an operator support system can provide detailed support information based on detailed models and utilizing detailed simulation of plant dynamics and/or complicated inference algorithms. However, human operators may not understand the detailed support information under high mental pressure in an abnormal plant condition. In such a case, it is important how to provide essential and understandable support information. This paper deals with a technique to simplify functional models in order to display operator support information that is generated based on detailed functional models. This paper defines eight cognitive states of human operators from the viewpoint of cognitive abilities of human. In addition, three ways to simplify functional models are identified.

Today’s scenario shows that mostly everywhere especially automotive industry prefers to use lightweight materials to increase the efficiency of vehicles. Fiber Reinforced Thermoplastics (FRT) are the commonly used composites for this purpose due to their abundant availability, cheaper, lighter than metals, non-corrosive and also satisfactorily efficient etc.. For injection molded parts, glass and carbon fibers are the commonly used ones to enhance their mechanical and thermal properties. The orientation of fibers in the parts plays a vital role in making the mechanical properties better. In this work, manual polishing and scanning technique using an optical microscope is implemented to observe the flow pattern of the fibers. The samples are injection-molded products of Polypropylene (PP) reinforced with 50% and 40% weightage of long glass fibers in it. The glass fibers have an average length of 25 mm and average diameter of 17 µm are reinforced with polypropylene in the form of pellets and are used in the injection molding machine to form the product. The sample cut out of the product is then put inside the PMMA, polished and scanned in the cross-sectional direction to see the flow of fibers in the composite. Using 5 grinding papers and 2 polishing papers, the sample is polished using a grinder-polisher. The polished samples are scanned under an optical microscope layer by layer and the microscope is operated using a software, ‘pylon viewer’. The scanned images show the fibers’ flow layer by layer throughout the part. Defects like-fiber bundles, voids and weld lines in the samples are discovered during the work. The flow phenomenon of fibers is observed in all the layers and there is no layered structure and the fibers are randomly oriented in-plane. The flow phenomenon is more likely to be plug flow.Today’s scenario shows that mostly everywhere especially automotive industry prefers to use lightweight materials to increase the efficiency of vehicles. Fiber Reinforced Thermoplastics (FRT) are the commonly used composites for this purpose due to their abundant availability, cheaper, lighter than metals, non-corrosive and also satisfactorily efficient etc.. For injection molded parts, glass and carbon fibers are the commonly used ones to enhance their mechanical and thermal properties. The orientation of fibers in the parts plays a vital role in making the mechanical properties better. In this work, manual polishing and scanning technique using an optical microscope is implemented to observe the flow pattern of the fibers. The samples are injection-molded products of Polypropylene (PP) reinforced with 50% and 40% weightage of long glass fibers in it. The glass fibers have an average length of 25 mm and average diameter of 17 µm are reinforced with polypropylene in the form of pellets and are used in the...

Combining such methods of plasma registration as spectral, probe and optical diagnostics, in this paper propagation of laser plasma in a vacuum magnetic field was studied. By means of Langmuir and magnetic probes such plasma parameters as velocity and the angle of expansion were measured, as well as the size of magnetic cavity. Using optical monochromator combined with CCD a Doppler broadening of a number of ionic and atomic lines was measured and the transversal speed of the plasma cloud expansion was calculated. The data plasma cloud propagation velocity and expansion angle obtained by two methods was compared with gated imaging data and magnetic probe measurements of cavity size.Combining such methods of plasma registration as spectral, probe and optical diagnostics, in this paper propagation of laser plasma in a vacuum magnetic field was studied. By means of Langmuir and magnetic probes such plasma parameters as velocity and the angle of expansion were measured, as well as the size of magnetic cavity. Using optical monochromator combined with CCD a Doppler broadening of a number of ionic and atomic lines was measured and the transversal speed of the plasma cloud expansion was calculated. The data plasma cloud propagation velocity and expansion angle obtained by two methods was compared with gated imaging data and magnetic probe measurements of cavity size.

In this paper, we propose and study a time-delay compartmental model for human immunodeficiency virus (HIV) transmission, a disease which may lead to an advanced stage of infection called acquired immunodeficiency syndrome (AIDS), in a sexually active population with the presence of media coverage. The inclusion of vertical transmission in the recruitment of infected individuals is also considered. Moreover, two time delays are incorporated in the model. One delay τ1 covers the period from the time of gathering statistical data on the total number of infections in the community up to the time that these information are reported to the public through media. The other delay τ2 corresponds to the period that an infected newborn baby reaches the age of sexual maturity. If the threshold value R0 < 1, then the only equilibrium point is the disease-free equilibrium which is globally asymptotically stable. If the threshold values R0 and R00 are both greater than 1, then a unique endemic equilibrium exists, which is globally asymptotically stable when media coverage is not considered. When there is no vertical transmission but media coverage is considered, the system undergoes a Hopf bifurcation at some critical value of the media delay. Numerical simulations are presented to illustrate theoretical results.In this paper, we propose and study a time-delay compartmental model for human immunodeficiency virus (HIV) transmission, a disease which may lead to an advanced stage of infection called acquired immunodeficiency syndrome (AIDS), in a sexually active population with the presence of media coverage. The inclusion of vertical transmission in the recruitment of infected individuals is also considered. Moreover, two time delays are incorporated in the model. One delay τ1 covers the period from the time of gathering statistical data on the total number of infections in the community up to the time that these information are reported to the public through media. The other delay τ2 corresponds to the period that an infected newborn baby reaches the age of sexual maturity. If the threshold value R0 < 1, then the only equilibrium point is the disease-free equilibrium which is globally asymptotically stable. If the threshold values R0 and R00 are both greater than 1, then a unique endemic equilibrium exists, which ...

Spherical Tokamak (ST) path to Fusion has been proposed [1] and experiments on STs demonstrated feasibility of this approach. Advances in High Temperature Superconductor technology [2] allows significant increase in the toroidal field (TF) which was found to improve confinement in STs. The combination of the high normalised plasma pressure, β, which has been achieved in STs [3], and high TF that can be produced by HTS TF magnets, opens a path to lower-volume fusion reactors, in accordance with the fusion power scaling proportional to β2Bt4V. Modular approach then becomes an alternative to high power, GW-scale Fusion reactors [4,5]. Feasibility of low-power compact ST reactor module and physics and engineering challenges of the accelerated, ST path to Fusion Power are discussed in this paper, on example of the first our prototype on this route, high-field compact spherical tokamak ST40.Spherical Tokamak (ST) path to Fusion has been proposed [1] and experiments on STs demonstrated feasibility of this approach. Advances in High Temperature Superconductor technology [2] allows significant increase in the toroidal field (TF) which was found to improve confinement in STs. The combination of the high normalised plasma pressure, β, which has been achieved in STs [3], and high TF that can be produced by HTS TF magnets, opens a path to lower-volume fusion reactors, in accordance with the fusion power scaling proportional to β2Bt4V. Modular approach then becomes an alternative to high power, GW-scale Fusion reactors [4,5]. Feasibility of low-power compact ST reactor module and physics and engineering challenges of the accelerated, ST path to Fusion Power are discussed in this paper, on example of the first our prototype on this route, high-field compact spherical tokamak ST40.

In this paper, the isolated DC-DC converters fly back, forward converter, and hybrid converter topologies are considered for analysis. However, each topology has definite boundaries that are hard to resolve that can be overcome by the hybrid topology. This paper presents a hybrid type of forward, and fly back converter, allocation of the transformer utilization factor a better manner, has exceptionally high voltage gain and high efficiency. Achieving soft switching with control and design is easy. The forward fly back converters are simulated using MATLAB Simulink employing the results are analyzed and compared the efficiencies with theoretical and simulated values. The theoretical analysis of flyback-forward converter using DSPIC30F4011 is verified by comparing the theoretical and simulation results with a prototype of 100W and 2 kHz switching frequency.

High speed vehicle as a vibration system, resonance generated in flight may be harmful to high speed vehicles. It is possible to solve the resonance problem by acquiring the natural frequency of the high-speed aircraft and then taking some measures to avoid the natural frequency of the high speed vehicle. Therefore, In this paper, the modal test of the high speed vehicle was carried out by using the running hammer method and the PolyMAX modal parameter identification method. Firstly, the total frequency response function, coherence function of the high speed vehicle are obtained by the running hammer stimulation test, and through the modal assurance criterion (MAC) to determine the accuracy of the estimated parameters. Secondly, the first three order frequencies, the pole steady state diagram of the high speed vehicles is obtained by the PolyMAX modal parameter identification method. At last, the natural frequency of the vibration system was accurately obtained by the running hammer method.High speed vehicle as a vibration system, resonance generated in flight may be harmful to high speed vehicles. It is possible to solve the resonance problem by acquiring the natural frequency of the high-speed aircraft and then taking some measures to avoid the natural frequency of the high speed vehicle. Therefore, In this paper, the modal test of the high speed vehicle was carried out by using the running hammer method and the PolyMAX modal parameter identification method. Firstly, the total frequency response function, coherence function of the high speed vehicle are obtained by the running hammer stimulation test, and through the modal assurance criterion (MAC) to determine the accuracy of the estimated parameters. Secondly, the first three order frequencies, the pole steady state diagram of the high speed vehicles is obtained by the PolyMAX modal parameter identification method. At last, the natural frequency of the vibration system was accurately obtained by the running hammer method.

The coastal areas of Java, especially Semarang and Demak, are tidal flooding-prone areas. In fact, tidal flooding decreases the quality of life in coastal areas due to the capacity of seawater in destroying the building, houses, and environment. One innovation is introduced in this paper, which is the premixed mortar additive to repair masonry walls of house in tidal-prone areas. Principally, some measures should be done to address the problems caused by tidal flooding. In this research, masonry walls were improved by applying premixed mortar additive. The results were investigated after its long term performance, for more than one year, by using non destructive Rebound Hammer Test. This research was conducted by experimental activity. There were two masonry walls that had been repaired about a year ago. Some old masonry and concrete bricks of the walls had been substituted by new concrete bricks made of polymer-modified mortar with Moringa oleifera and Gracilaria Sp. and then covered by premixed mortar additive. Those masonry walls were built in Sriwulan village, Sayung and Pucang Gading— as the control site. Non destructive Rebound Hammer Test was applied on the masonry walls aged 12, 13, and 14 months. Each masonry wall was tested by 5 (five) zones (A, B, C, D, and E). Ten shoots were applied on each zone. The findings revealed: 1) In dry area, Pucang Gading site, there is a consistent performance of compressive strength masonry wall aged 12, 13, and 14 months, 2) In tidal flooding-prone area, Sayung site, there is fluctuative performance of compressive strength masonry wall aged 12, 13, and 14 months, 3) Compressive strength of masonry walls aged 14 months in Pucang Gading site is generally fluctuative, particularly at zone A to E (39.4 MPa to 44 MPa), while in Sayung site, compressive strength of zone A to E indicates declining values (44.3 MPa to 40.8 MPa), 4) At age 14 months, the compressive strength of zone B and E in Sayung site is lower than that in Pucang Gading site, due to tidal flooding, and 5) Slight distinction of compressive strength in Pucang Gading and Sayung site may be provided by premixed mortar additive that covers the walls.The coastal areas of Java, especially Semarang and Demak, are tidal flooding-prone areas. In fact, tidal flooding decreases the quality of life in coastal areas due to the capacity of seawater in destroying the building, houses, and environment. One innovation is introduced in this paper, which is the premixed mortar additive to repair masonry walls of house in tidal-prone areas. Principally, some measures should be done to address the problems caused by tidal flooding. In this research, masonry walls were improved by applying premixed mortar additive. The results were investigated after its long term performance, for more than one year, by using non destructive Rebound Hammer Test. This research was conducted by experimental activity. There were two masonry walls that had been repaired about a year ago. Some old masonry and concrete bricks of the walls had been substituted by new concrete bricks made of polymer-modified mortar with Moringa oleifera and Gracilaria Sp. and then covered by premixed mortar a...

This paper presents the design and development of the distributed ultrasonic waveguide temperature sensors using some stepped-helical structures. Distributed sensing has several applications in various industries (oil, glass, steel) for measurement of physical parameters such as level, temperature, viscosity, etc. This waveguide incorporates a special notch or bend for obtaining ultrasonic wave reflections from the desired locations (Gage-lengths) where local measurements are desired. In this paper, a multi-location measurement wave-guide, with a measurement capability of 18 locations in a single wire, has been fabricated. The distribution of these sensors is both in the axial as well as radial directions using a stepped-helical spring configuration. Also, different high temperature materials have been chosen for the wave-guide. Both lower order axi-symmetric guided ultrasonic modes (L(0,1) and T(0,1)) were employed. These wave modes were generated/received (pulse-echo approach) using conventional longitu...

The ITER baseline foresees 2 Heating Neutral Beams (HNB’s) operating at 1 MeV 40 A D0, each capable of delivering 16.5 MW of deuterium neutrals to the plasma, with a 3rd HNB injector foreseen as an upgrade option that would bring up the total neutral beam power to 50MW [1]. In addition a dedicated Diagnostic Neutral Beam (DNB) will be injecting 100 keV 60 A of H0 for charge exchange recombination spectroscopy (CXRS) [2]. This paper highlights the impact of the staged approach on the ITER NBI, presents the new installation strategy and reports on the status of the adopted design refinements and the integration of the HNB’s and the DNB into the ITER plant.The ITER baseline foresees 2 Heating Neutral Beams (HNB’s) operating at 1 MeV 40 A D0, each capable of delivering 16.5 MW of deuterium neutrals to the plasma, with a 3rd HNB injector foreseen as an upgrade option that would bring up the total neutral beam power to 50MW [1]. In addition a dedicated Diagnostic Neutral Beam (DNB) will be injecting 100 keV 60 A of H0 for charge exchange recombination spectroscopy (CXRS) [2]. This paper highlights the impact of the staged approach on the ITER NBI, presents the new installation strategy and reports on the status of the adopted design refinements and the integration of the HNB’s and the DNB into the ITER plant.

This paper discusses the superelastic behavior of shape memory alloy, NiTi when used as reinforcement in concrete beams. The ability of NiTi to recover and reduce permanent deformations of concrete beams was investigated. Small-scale concrete beams, with NiTi reinforcement were experimentally investigated under monotonic loads. The behaviour of simply supported reinforced concrete (RC) beams hybrid with NiTi rebars and the control beam subject to monotonic loads were experimentally investigated. This paper is to highlight the ability of the SMA bars to recover and reduce permanent deformations of concrete flexural members. The size of the control beam is 125 mm × 270 mm × 1000 mm with 3 numbers of 12 mm diameter bars as main reinforcement for compression and 3 numbers of 12 mm bars as tension or hanger bars while 6 mm diameter at 100 mm c/c used as shear reinforcement bars for control beam respectively. While, the minimal provision of 200mm using the 12.7mm of superelastic Shape Memory Alloys were employed to replace the steel rebar at the critical region of the beam. In conclusion, the contribution of the SMA bar in combination with high-strength steel to the conventional reinforcement showed that the SMA beam has exhibited an improve performance in term of better crack recovery and deformation. Therefore the usage of hybrid NiTi with the steel can substantially diminish the risk of the earthquake and also can reduce the associated cost aftermath.

In the field of metal rolling, the quality of the steel roller’s surface is significant for the final rolling products, e.g. metal sheets or foils. Besides the dimensional accuracy and surface roughness, the optical uniformity of the roller surface is also required for high quality rolling application. The typical optical defects of rollers after finish grinding include speckles, chatter marks, feed traces, and combination of all above. Unlike surface roughness, the optical defects can hardly be characterized by the topography or scanning electrical microscope measurement. Only the inspection by bared eyes of experienced engineers appears to be the effective manner for surface optical defects examination for large steel rollers. In this paper, an on-site machine vision system is designed to add on to the roller grinding machine to capture the surface image, and then an improved optical defects segmentation algorithm is developed based on the active contour model. Finally, experiments are carried out to verify the efficacy of the improved model.In the field of metal rolling, the quality of the steel roller’s surface is significant for the final rolling products, e.g. metal sheets or foils. Besides the dimensional accuracy and surface roughness, the optical uniformity of the roller surface is also required for high quality rolling application. The typical optical defects of rollers after finish grinding include speckles, chatter marks, feed traces, and combination of all above. Unlike surface roughness, the optical defects can hardly be characterized by the topography or scanning electrical microscope measurement. Only the inspection by bared eyes of experienced engineers appears to be the effective manner for surface optical defects examination for large steel rollers. In this paper, an on-site machine vision system is designed to add on to the roller grinding machine to capture the surface image, and then an improved optical defects segmentation algorithm is developed based on the active contour model. Finally, experiments are carried out to ve...

The interaction of a shock wave with a rough free surface may lead to the ejection of high velocity (∼ km/s) particles of small size (∼ µm). This process is a safety issue for various applications such as pyrotechnics or inertial confinement fusion. To complement data obtained by other groups under explosive loading or plate impacts, we use laser driven shock loading to study microjetting from V-shaped grooves of various angles in copper and tin samples, with a combination of complementary experimental techniques. To simulate such experiments, we have chosen to use the Smoothed Particles Hydrodynamics formulation, well-suited for the very high strains involved in jet expansion and subsequent fragmentation. In this paper, we report some advances in this modelling effort, then we compare computed predictions with new experimental results including fragments size distributions inferred from post-test micro-tomography after soft recovery in a low density gel. Special focus is made on the dependence of the ejecta ballistic properties (velocity and mass distributions) on numerical parameters such as the initial inter-particular distance, the smoothing length and a random geometrical noise introduced to simulate inner irregularities of the material.The interaction of a shock wave with a rough free surface may lead to the ejection of high velocity (∼ km/s) particles of small size (∼ µm). This process is a safety issue for various applications such as pyrotechnics or inertial confinement fusion. To complement data obtained by other groups under explosive loading or plate impacts, we use laser driven shock loading to study microjetting from V-shaped grooves of various angles in copper and tin samples, with a combination of complementary experimental techniques. To simulate such experiments, we have chosen to use the Smoothed Particles Hydrodynamics formulation, well-suited for the very high strains involved in jet expansion and subsequent fragmentation. In this paper, we report some advances in this modelling effort, then we compare computed predictions with new experimental results including fragments size distributions inferred from post-test micro-tomography after soft recovery in a low density gel. Special focus is made on the dependence of the eje...

A next generation heavy ion accelerator complex HIAF (High Intensity heavy ion Accelerator Facility) was proposed by IMP and officially approved for nuclear physics and high energy density physics research. HIAF requests ion source that is able to deliver 50 pμA of 238U35+ pulsed beam and 25 pμA of 238U35+ CW beam for injector of a superconducting heavy ion linac. In order to meet the beam intensity requirements of highly charged heavy ions, a 45 GHz superconducting ECR ion source FECR (a Fourth generation ECR ion source) is under intense R&D at IMP. The effective power absorption form the microwaves to the plasma is key issue for increasing the beam intensity. Therefore, we introduced a 45 GHz gyrotron system which is capable for providing output power up to 20 kW in both CW and pulse modes as a microwave power source for FECR. Other than the gyrotron oscillator, the microwave power transmission coupling and ECR heating are critical issues for FECR. Since the wavelength of 45 GHz microwave is about 6.67 mm and the maximum power level is 20 kW, the quasi-optical transmission scheme is utilized for high power transmission. The technical details of transmission line and coupling system will be presented in this paper. After off-line tests of microwave transmission efficiency and mode purity, 45 GHz gyrotron microwave source will be commissioned with SECRAL II (a superconducting ECR ion source optimized for 28 GHz operation), and some preliminary results of ECR heating and intense beam production will be discussed in this paper.

This paper focuses on the impact towards the performance of silicon nanowire field-effect transistor (SiNW-FET) for biosensing application based on different channel lengths of the nanowire. A device numerical modelling tool, Silvaco ATLAS was used to design three p-type SiNW-FET biosensors with different lengths of 0.5, 1.0, and 10.0 μm. The designed devices were simulated in order to observe and compare the effect of different channel length towards the electrical characteristic of the devices. Increase of the nanowire channel length had caused reduction of drain current, ID flowed through the channel from drain to source region. This is related to the increase of electrical resistance, R of the nanowire with the increase of nanowire length, L. In a way to study the effect of different channel lengths on the performance of the SiNW-FET biosensor, several negatively interface charge densities, QF (i.e. −0.1×1012, −0.5×1012, and −1×l012 cm−2) were introduced on the surface of the SiNW channel to represent as the actual target deoxyribonucleic acid (DNA) captured by the bioreceptor of the biosensor. Based on the results, these negatively QF attracted the hole carriers below the surface of p-type nanowire to form an accumulation of charge carriers in the channel, causing an increase in the device output ID. Increase of the applied negative charge density had allowed for more ID to flow across the channel between drain and source region. The changes of ID with the applied QF are utilized to determine the sensitivities and limit of detections (LOD) for all designed biosensor with different channel lengths. In comparison, the smallest nanowire length of 0.5 μm produced the highest sensitivity and lowest LOD of 2.17 μA/cm−2 and 7.85×1010 cm−2, respectively, hence demonstrates better performance of SiNW-FET biosensor for the detection of specific charged DNA in analyte.This paper focuses on the impact towards the performance of silicon nanowire field-effect transistor (SiNW-FET) for biosensing application based on different channel lengths of the nanowire. A device numerical modelling tool, Silvaco ATLAS was used to design three p-type SiNW-FET biosensors with different lengths of 0.5, 1.0, and 10.0 μm. The designed devices were simulated in order to observe and compare the effect of different channel length towards the electrical characteristic of the devices. Increase of the nanowire channel length had caused reduction of drain current, ID flowed through the channel from drain to source region. This is related to the increase of electrical resistance, R of the nanowire with the increase of nanowire length, L. In a way to study the effect of different channel lengths on the performance of the SiNW-FET biosensor, several negatively interface charge densities, QF (i.e. −0.1×1012, −0.5×1012, and −1×l012 cm−2) were introduced on the surface of the SiNW channel to represent...

To solve the problems in the DEM simulations of the screening process of a swing-bar sieve, in this paper we propose the real-virtual boundary method to build the geometrical model of the screen deck on a swing-bar sieve. The motion of the swing-bar sieve is modelled by the planer multi-body kinematics. A coupled model of the discrete element method (DEM) with multi-body kinematics (MBK) is presented to simulate the flowing and passing processes of soybean particles on the screen deck. By the comparison of the simulated results with the experimental results of the screening process of the LA-LK laboratory scale swing-bar sieve, the feasibility and validity of the real-virtual boundary method and the coupled DEM-MBK model we proposed in this paper can be verified. This work provides the basis for the optimization design of the swing-bar sieve with circular apertures and complex motion.

The emerging applications of coordination and cooperation between mobile robots, as well as interaction between mobile robots and humans, demands for an early and well designed robotic education. In addition, research and development in this area needs to be supported with an-easy-to-implement mobile robot platform. An availability of a low-cost and open source mobile robots will be beneficial, especially in a development country such as Indonesia. In this paper we propose a low cost and open source mobile robot platform that can be used for education and research specific in mobile robots and coordination between the robots. The “low cost” is defined as the availability and easiness to find the components in Indonesia or at least easily found in online shop. The “open source” means that the resulting design and implementation can be accessed in open source library and follow the GNU license. The first generation of the robot has been validated in terms of individual sensor and performance. The platform has been extended up to second generation and is used in different applications such as indoor mapping and remote control manipulation.The emerging applications of coordination and cooperation between mobile robots, as well as interaction between mobile robots and humans, demands for an early and well designed robotic education. In addition, research and development in this area needs to be supported with an-easy-to-implement mobile robot platform. An availability of a low-cost and open source mobile robots will be beneficial, especially in a development country such as Indonesia. In this paper we propose a low cost and open source mobile robot platform that can be used for education and research specific in mobile robots and coordination between the robots. The “low cost” is defined as the availability and easiness to find the components in Indonesia or at least easily found in online shop. The “open source” means that the resulting design and implementation can be accessed in open source library and follow the GNU license. The first generation of the robot has been validated in terms of individual sensor and performance. The platform h...

In this paper is presented a wind turbine model operating in the maximum power zone and an H∞ controller is synthesized for the system. The developed turbine model consists of: a model of the wind speed, mechanical and electrical model of the generator and a model of the tower oscillations. The controller adjusts the pitch angle of the blades so that the rotor angular velocity stays close to its nominal value and as a result the tower oscillations are decreased. Finally, the operation of the closed-loop system model is validated by simulationsIn this paper is presented a wind turbine model operating in the maximum power zone and an H∞ controller is synthesized for the system. The developed turbine model consists of: a model of the wind speed, mechanical and electrical model of the generator and a model of the tower oscillations. The controller adjusts the pitch angle of the blades so that the rotor angular velocity stays close to its nominal value and as a result the tower oscillations are decreased. Finally, the operation of the closed-loop system model is validated by simulations

This paper presents modelling of both single and double-phase powder sintering processes at the macroscopic level. In particular, its constitutive formulation, numerical implementation and numerical tests are described. The macroscopic constitutive model is based on the assumption that the sintered material is a continuous medium. The parameters of the constitutive model for material under sintering are determined by simulation of sintering at the microscopic level using a micro-scale model. Numerical tests were carried out for a cylindrical specimen under hydrostatic and uniaxial pressure. Results of macroscopic analysis are compared against the microscopic model results. Moreover, numerical simulations are validated by comparison with experimental results. The simulations and preparation of the model are carried out by Abaqus FEA - a software for finite element analysis and computer-aided engineering. A mechanical model is defined by the user procedure “Vumat” which is developed by the first author in Fortran programming language. Modelling presented in the paper can be used to optimize and to better understand the process.This paper presents modelling of both single and double-phase powder sintering processes at the macroscopic level. In particular, its constitutive formulation, numerical implementation and numerical tests are described. The macroscopic constitutive model is based on the assumption that the sintered material is a continuous medium. The parameters of the constitutive model for material under sintering are determined by simulation of sintering at the microscopic level using a micro-scale model. Numerical tests were carried out for a cylindrical specimen under hydrostatic and uniaxial pressure. Results of macroscopic analysis are compared against the microscopic model results. Moreover, numerical simulations are validated by comparison with experimental results. The simulations and preparation of the model are carried out by Abaqus FEA - a software for finite element analysis and computer-aided engineering. A mechanical model is defined by the user procedure “Vumat” which is developed by the first author in F...

The laser forming technique has an important disadvantage, which is the limitation of plastic deformation generated by a single laser beam pass. To increase the plastic deformation it is possible to apply external forces in the laser forming process. In this paper, we investigate the influence of external pre-loads on the laser bending of steel plate. The pre-loads investigated generate bending towards the laser beam. The thermal, elastic-plastic analysis is performed using the commercial nonlinear finite element analysis package ABAQUS. The focus of the paper is to identify how this pattern of the pre-load influence the final bend angle of the plate.

Every production process requires monitoring system, so the desired efficiency and productivity can be monitored at any time. This system is also needed in the job shop type of manufacturing which is mainly influenced by the manufacturing lead time. Processing time is one of the factors that affect the manufacturing lead time. In a conventional company, the recording of processing time is done manually by the operator on a sheet of paper. This method is prone to errors. This paper aims to overcome this problem by creating a system which is able to record and monitor the processing time automatically. The solution is realized by utilizing electric current sensor, barcode, RFID, wireless network and windows-based application. An automatic monitoring device is attached to the production machine. It is equipped with a touch screen-LCD so that the operator can use it easily. Operator identity is recorded through RFID which is embedded in his ID card. The workpiece data are collected from the database by scanning the barcode listed on its monitoring sheet. A sensor is mounted on the machine to measure the actual machining time. The system’s outputs are actual processing time and machine’s capacity information. This system is connected wirelessly to a workshop planning application belongs to the firm. Test results indicated that all functions of the system can run properly. This system successfully enables supervisors, PPIC or higher level management staffs to monitor the processing time quickly with a better accuracy.Every production process requires monitoring system, so the desired efficiency and productivity can be monitored at any time. This system is also needed in the job shop type of manufacturing which is mainly influenced by the manufacturing lead time. Processing time is one of the factors that affect the manufacturing lead time. In a conventional company, the recording of processing time is done manually by the operator on a sheet of paper. This method is prone to errors. This paper aims to overcome this problem by creating a system which is able to record and monitor the processing time automatically. The solution is realized by utilizing electric current sensor, barcode, RFID, wireless network and windows-based application. An automatic monitoring device is attached to the production machine. It is equipped with a touch screen-LCD so that the operator can use it easily. Operator identity is recorded through RFID which is embedded in his ID card. The workpiece data are collected from the database by scanni...

The reliability of the crane product in engineering is the core competitiveness of the product. This paper used Monte Carlo method analyzed the reliability of the weld metal structure of the bridge crane whose limit state function is mathematical expression. Then we obtained the minimum reliable welding feet height value for the welds between cover plate and web plate on main beam in different coefficients of variation. This paper provides a new idea and reference for the growth of the inherent reliability of crane.

Insulation oils are a vital part in power transformers. Insulation oil is not only work as electrical insulation but also as a coolant inside the transformer. Due to the increasing tight regulations on the environment and safety in recent years, vegetable oils are being considered for insulation oils in power transformer. This paper presents two conditions of Rapeseed Oil (RO), which are as received (new) and dried (dry) under difference uniform field electrodes configuration (mushroom-to-mushroom and sphere-to-sphere) with gap distance at 2.5 mm as recommended by the international standards. A comparative study of AC breakdown voltage, dissipation factor (tan δ), and resistivity under variation of temperature were investigated. The experimental works were done according to the IEC 60156 and IEC 60247 standards. The results indicated that the breakdown voltages of both condition are comparable to mineral oil. The dielectric constant and resistivity of two conditions are decreased along with the increasing temperature. However, the dissipation factor properties rose up along with the temperature. The Weibull distribution was used to determine the withstand voltages at 1% and 50% for RO in two probabilities conditions.Insulation oils are a vital part in power transformers. Insulation oil is not only work as electrical insulation but also as a coolant inside the transformer. Due to the increasing tight regulations on the environment and safety in recent years, vegetable oils are being considered for insulation oils in power transformer. This paper presents two conditions of Rapeseed Oil (RO), which are as received (new) and dried (dry) under difference uniform field electrodes configuration (mushroom-to-mushroom and sphere-to-sphere) with gap distance at 2.5 mm as recommended by the international standards. A comparative study of AC breakdown voltage, dissipation factor (tan δ), and resistivity under variation of temperature were investigated. The experimental works were done according to the IEC 60156 and IEC 60247 standards. The results indicated that the breakdown voltages of both condition are comparable to mineral oil. The dielectric constant and resistivity of two conditions are decreased along with the increasing...