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Nitrogen is the most important substance in fertilizer to produce high quality harvest. Nitrogen, which comes from the air, can formed as ammonia and nitrate in fertilizer. In industry, the most common fertilizer contain ammonia not nitrate because of its production process easiness compared to nitrate. Ammonia has fertilization efficiency 40% and nitrate has fertilization efficiency 60%. Industrial fertilizer production process nowadays, ammonia synthesis which called Haber-Bosch process, still not environmental friendly and also consume high energy. Environmental friendly and lower energy process is needed to produce fertilizer. Some study related to nitrogen fixation to produce fertilizer has been made including plasma electrolysis method. Plasma electrolysis is an effective method to fix nitrogen from the air because of its ability to produce OH radicals and other radicals to break the N2 bound to produce nitrate with lower energy consumption compared to Haber-Bosch process. This method is implemented in batch reactor with variation of anode depth. This study has proven can produce nitrate up to 1,200 ppm in condition power 800 watt, anode depth 1.5-3.5 cm and Na2SO4 electrolyte concentration 0.02 M.

Flotation deinking has industrially applied but several problems keep unsolved because limitations have to compete with several variables present. Flotation deinking is multi variables process, so studying flotation deinking is still interesting. In this research, the amount of variables was reduced and focused to the performance comparison between flotation deinking of old newspaper (ONP) using biodegradable fatty acid of morinda citrifolia as the raw bio surfactant (RBS) and biodegradable fatty acid of palm oil that had been converted to be commercial surfactant (CS). The flotation was done at laboratory flotation cell equipped with orifice at different diameter (orifice number 20, 40 and 60) with adjustable airflow rate. Brightness and Effective Residual Ink Concentration (ERIC) of the deinked pulp were measured. The best results were achieved on orifice number 40 with the highest brightness of 41.96 °ISO and 40.96 °ISO when using CS and RBS respectively, and lowest ERIC of 896.82 ppm and 1001.72 ppm when using CS and RBS respectively. The percentage delta of deinking power characteristic between CS and RBS was 2.36% and 11.70% for brightness and ERIC, respectively.

The fabrication and characterization on reduced graphene oxide field effect transistor (RGO-FET) were demonstrated using a spray deposition method for biological sensing device purpose. A spray method is a fast, low-cost and simple technique to deposit graphene and the most promising technology due to ideal coating on variety of substrates and high production speed. The fabrication method was demonstrated for developing a label free aptamer reduced graphene oxide field effect transistor biosensor. Reduced graphene oxide (RGO) was obtained by heating on hot plate fixed at various temperatures of 100, 200 and 300°C, respectively. The surface morphology of RGO were examined via atomic force microscopy to observed the temperature effect of produced RGO. The electrical measurement verify the performance of electrical conducting RGO-FET at temperature 300°C is better as compared to other temperature due to the removal of oxygen groups in GO. Thus, reduced graphene oxide was a promising material for biosensor application.

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.

Now a days red emitting Mn4+ activated dialkali fluorosilicate phosphors have found applications in solid state lighting and displays. In this paper we describe development of K2SiF6 phosphor doped with Mn synthesized by simple method using Si metal powder with addition of oxidizing agent KMnO4. The photoluminescence spectra of K2SiF6:Mn show that emission is in the red region. In addition to this we studied LED spectra by coating the LED with phosphor mixed in different proportions with epoxy.Now a days red emitting Mn4+ activated dialkali fluorosilicate phosphors have found applications in solid state lighting and displays. In this paper we describe development of K2SiF6 phosphor doped with Mn synthesized by simple method using Si metal powder with addition of oxidizing agent KMnO4. The photoluminescence spectra of K2SiF6:Mn show that emission is in the red region. In addition to this we studied LED spectra by coating the LED with phosphor mixed in different proportions with epoxy.

A method of thermal reduction of graphene oxide has been developed. Samples of paper-like graphene oxide film produced by the standard Hummers method were experienced by thermal processing at various temperatures which resulted in a partial reduction of graphene oxide which accompanied with an enhancement of the conductivity of this material. The most pronounced jump in the conductivity occurs at the annealing temperature of about 170°C, when the conductivity of the samples increased by 5 orders of magnitude comparing to the initial samples. The samples of partially reduced graphene oxide obtained were used for reinforcement of a steel surface. The reinforcement procedure was described in detail in the preceding work [1], where fullerene C60 and nanocarbon soot formed as a result of electrical arc sputtering followed by the extraction of fullerenes were used as a reinforcing coating. A film of partially reduced graphene oxide is applied on a steel surface after which the surface is experienced by laser. The dependences of the reinforcement degree on the degree of the graphene oxide reduction and the laser intensity are measured. The results of measurements indicate a notable (up to 400 %) enhancement of the microhardness of the surface processed so that the depth of the reinforcement layer accounts tens micrometers.A method of thermal reduction of graphene oxide has been developed. Samples of paper-like graphene oxide film produced by the standard Hummers method were experienced by thermal processing at various temperatures which resulted in a partial reduction of graphene oxide which accompanied with an enhancement of the conductivity of this material. The most pronounced jump in the conductivity occurs at the annealing temperature of about 170°C, when the conductivity of the samples increased by 5 orders of magnitude comparing to the initial samples. The samples of partially reduced graphene oxide obtained were used for reinforcement of a steel surface. The reinforcement procedure was described in detail in the preceding work [1], where fullerene C60 and nanocarbon soot formed as a result of electrical arc sputtering followed by the extraction of fullerenes were used as a reinforcing coating. A film of partially reduced graphene oxide is applied on a steel surface after which the surface is experienced by laser. T...

Over the past decades the piston is designed to transfer force to the crank shaft through a piston rod by the expansion of gases in the cylinder. During working piston has to tolerate the cyclic gas pressure and the inertial forces, due to which the piston experiences fatigue damages such as piston side wear, piston head cracks and so on. Earlier pistons were made up of cast iron or aluminium due to their lightweight and high heat transfer rate. After some experiments it was noted that on heating cast iron expands due to which it covers the clearance level that comes to seize the engine. This paper aims to design a piston using composite material such as Al-GHS 1300, Al-GHY 1250, Al-Si-C, A6061 and A4032 that will differ the material and the characteristics of the traditional engine piston. This paper describes the thermal and mechanical properties of the piston when the study is done by taking five different materials.

There are many important roles of the orthotic insoles, such as for the convenience purpose of diabetic patient’s foot problem, and also to enhance athlete’s performance in sports. Therefore, highly customised insoles were in demand, where it has to be fabricated by moulding plaster of Paris on the person’s leg to customise the insole. The main purpose of the paper is to study the ability to implement additive manufacturing technology in the fabrication process of customised orthotics insole. The recent invention of flexible material (Filaflex) in Fused Deposition Modelling is the most significant reason that makes this fabrication process possible. By implementing a new approach to the 3D scanning of the foot, we produced the computer-aided drafting (CAD) drawing which was able to modify to desired shape and dimension. After the editing has been completed, the file was converted to Stereolithography format file (STL) as to enable it to be printed using Makerware or any other related software by sending command (G-code) to Flashforge 3D printer. The printed insole was tested its fit, form and function (also known as 3F). In the end, printed insole performs the function test which measures the plantar pressure of the foot compared with bare foot. The results show that the insole distributes pressure well throughout the foot surface, in which it reduced the peak pressure to half from 218KPa to 109KPa. Hence, it is concluded that the method proposed in this paper can produce a functional insole so that it can be the alternative way to make customised orthotic insoles.

In this paper, considering the traditional reactive power optimization cannot realize the continuous voltage adjustment and voltage stability, a dynamic reactive power optimization strategy is proposed in order to achieve both the minimization of network loss and high voltage stability with wind power. Due to the fact that wind power generation is fluctuant and uncertain, electrical equipments such as transformers and shunt capacitors may be operated frequently in order to achieve minimization of network loss, which affect the lives of these devices. In order to solve this problem, this paper introduces the derivation process of analytical impedance ratio based on Thevenin equivalent. Thus, the multiple objective function is proposed to minimize the network loss and analytical impedance ratio. Finally, taking the improved IEEE 33-bus distribution system as example, the result shows that the movement of voltage control equipment has been reduced and network loss increment is controlled at the same time, wh...

Air filtration system plays an important role in getting good quality air into turbo machinery such as gas turbine. The filtration system and filters improve the quality of air and protect the gas turbine parts from contaminants which could bring damage. This paper is focused on the configuration of the self-cleaning canister filter in order to obtain the minimal pressure drop along the filter. The configuration includes a modified canister filter cap that is based on the basic geometry that conforms to industry standard. This paper describes the use of CFD to simulate and analyze the flow through the filter. This tool is also used to monitor variables such as pressure and velocity along the filter and to visualize them in the form of contours, vectors and streamlines. In this study, the main parameter varied is the inlet velocity set in the boundary condition during simulations, which are 0.032, 0.063, 0.094 and 0.126 m/s respectively. The data obtained from simulations are then validated with reference ...

In LED-based visible light communication, the choice of light source device is an important issue. In this paper, the frequency response (FR) of different types of blue LEDs and phosphors is measured. On the basis of that, this paper proposes the FR model of phosphor and supplements the FR model of blue LED. And also, a method is proposed to calculate the FR of phosphor coated LEDs using FR of blue LED and that of phosphor. On this basis, this paper analyses the influencing factors of the FR of blue LED and FR of phosphor respectively. It provides guidance for not only selecting the light source device but also selecting and blending phosphor in visible light communication based on LED.

In accordance with the problem such as isolated subsystems, weak system linkage and expansibility of the bus type buildings management system, this paper based on the modern intelligent buildings has studied some related technologies of the intelligent buildings and internet of things, and designed system architecture of the intelligent buildings based on the Internet of Things. Meanwhile, this paper has also analyzed wireless networking modes, wireless communication protocol and wireless routing protocol of the intelligent buildings based on the Internet of Things.

This paper demonstrates the idea of data transmission at a very higher rate (Tbits/s) through optical fibers in a passive optical network using the most efficient data transmission technique widely used in wireless communication that is orthogonal frequency division multiplexing. With an increase in internet users, data traffic has also increased significantly and the current dense wavelength division multiplexing (DWDM) systems may not support the next generation passive optical networks (PONs) requirements. The approach discussed in this paper allows to increase the downstream data rate per user and extend the standard single-mode fiber reach for future long-haul applications. All-optical OFDM is a promising solution for terabit per second capable single wavelength transmission, with high spectral efficiency and high tolerance to chromatic dispersion.

This paper mainly introduces the research principle and implementation method of the small UAV navigation attitude system based on MEMS devices. The Gauss - Newton method based on least squares is used to calibrate the MEMS accelerometer and gyroscope for calibration. Improve the accuracy of the attitude by using the modified complementary filtering to correct the attitude angle error. The experimental data show that the design of the attitude and attitude system in this paper to meet the requirements of small UAV attitude accuracy to achieve a small, low cost.

Engineering a lab-on-a-chip (LoC) to perform the DNA polymerase chain reaction (PCR) for malaria detection is the ultimate goal of this study. This paper investigates the ability to fabricate an LoC kit using conventional method to achieve the lowest production cost by using existing fabrication process. It has been known that majority of LoC was made of polydimethylsiloxane (PDMS) which in this study was realized through a contact mold process. CNC milling process was utilized to create channel features in the range of 150-250 µm on the mold. Characterization on the milling process was done to understand the shrinkage/contraction between mold to product, roughness and also angle of contact of PDMS surface. Ultimately, this paper also includes analysis on flow measurement and heat distribution of an assembled LoC PCR kit. The results show that the achieved dimension of microchannel is 227 µm wide with a roughness of 0.01 µm. The flow measurement indicates a deviation with simulation in the range of 10%. A heat distribution through the kit is achieved following the three temperature zones as desired.

A solar cavity receiver model for the dish collector system is designed in response to growing demand of renewable energy. In the present research field, no investigations into the geometric parameters of a cavity receiver have been performed. The cylindrical receiver in this study is composed of an enclosed bottom at the back, an aperture at the front, a helical pipe inside the cavity and an insulation layer on the external surface of the cavity. The influence of several critical receiver parameters on the thermal efficiency is analyzed in this paper: cavity inner diameter and cavity length. The thermal model in this paper is solved considering the cavity dimensions as variables. Implementing the model into EES, each parameter influence is separately investigated, and a preliminary optimization method is proposed.

Today’s rapid growth in air transportation demand leads to the problem of congestion in air traffic routes. In recent years, free flight concept is widely discussed as the solution to this problem. Free flight is a decentralized method of air traffic management, in which each aircraft has the freedom to self optimize its own route. Conflict detection and its subsequent resolution are the major challenges in the realization of this concept. Today’s modern navigation and surveillance equipment can ensure accurate conflict predictions. Once a conflict is detected, it should be avoided through suitable conflict avoidance maneuvers. An autopilot capable of initiating these conflict free maneuvers should be a necessary part of any aircraft in free flight to ensure conflict avoided flight. Controller design based on Sliding Mode Control (SMC) strategy is presented in this paper for the purpose of free flight autopilot implementation. Since SMC has the inherent property of robustness in sliding mode, it can ensure a highly efficient autopilot design. Conventional and reaching law approaches of SMC design are considered here for controller design. Conventional SMC technique usually exhibits an unacceptable phenomenon, viz., chattering. Reaching law approaches for SMC design are being investigated here so as to identify an appropriate strategy that can ensure near chattering free operation. Considering typical free flight conflict avoidance modes of operation, the performance of all the considered SMC strategies are compared through simulation studies. The comparison is based on their ability to reduce chattering and the effectiveness in ensuring quick conflict resolution maneuvers, so that an efficient controller for free flight autopilot system can be recommended.Today’s rapid growth in air transportation demand leads to the problem of congestion in air traffic routes. In recent years, free flight concept is widely discussed as the solution to this problem. Free flight is a decentralized method of air traffic management, in which each aircraft has the freedom to self optimize its own route. Conflict detection and its subsequent resolution are the major challenges in the realization of this concept. Today’s modern navigation and surveillance equipment can ensure accurate conflict predictions. Once a conflict is detected, it should be avoided through suitable conflict avoidance maneuvers. An autopilot capable of initiating these conflict free maneuvers should be a necessary part of any aircraft in free flight to ensure conflict avoided flight. Controller design based on Sliding Mode Control (SMC) strategy is presented in this paper for the purpose of free flight autopilot implementation. Since SMC has the inherent property of robustness in sliding mode, it can ensur...

The boost converter belongs to the family of indirect energy transfer converters. The inductor stores energy during switch on and the output capacitor deliver power to the load. During switch off condition, the stored inductive energy appears in series with the input source and supply the output. The paper deals with the small signal analysis of dc-dc boost converter. It is used in modeling the closed loop converter parameters. The boost converter produces an undesirable Right-Half Plane Zero (RHPZ) in the small signal analysis due to which the implementation of voltage mode control needs attention. This requires compensating the regulator such that the crossover frequency occurs well below the frequency of the RHP zero. The paper describes modeling of voltage mode control boost converter operating in continuous conduction mode.

Roller bearing is one of the vital parts of a rotating machine. Bearing failure can result in serious damage of the machine. This paper aims to develop a bearing fault diagnosis method using parameter evaluation technique to improve the diagnosis accuracy. The parameter evaluation technique is used to select five features that are used as predictors in multi-class support vector machine (SVM) classification. The purpose of this feature reduction was to avoid the curse of dimensionality and to increase the accuracy of the diagnosis. The diagnosis process was performed by classification of bearing states using one-against-one method multi-class SVM. Three types of kernel functions i.e., linear, polynomial, and Gaussian RBF were used in the SVM classification. The bearing conditions which is diagnosed in this paper were normal bearing, inner race fault, and outer race fault conditions. As a result, the classification performance of multiclass SVM using five selected features as the parameter have excellent p...

The main challenge of PMSM implementation in the adjustable-speed drives especially in automotive industry is to attain the optimal PMSM drive performance. Vector control is proved to be the best method in controlling synchronous machine such as PMSM. This paper objective is to design a speed control system for the manufactured inset rotor PMSM, which integrates the interleaved DC-DC boost converter, inverter, and sinusoidal pulse width modulation and fed by the battery bank DC source. The proposed speed control in this paper employs FOC vector control technique with PI controller which control both converter and inverter independently. This paper investigates the effectiveness of the proposed speed control method for driving the manufactured inset rotor PMSM. To verify the effectiveness of the designed speed control system, computer simulation is conducted. The motor performances are observed in operating condition with disturbance in form of sudden change of load torque. The simulation results show that the control method is stable but the rotor speed still affected by the given disturbance.

This paper focuses on the development of a wearable sensor system to identify the different types of badminton grip that is used by a player during training. Badminton movements and strokes are fast and dynamic, where most of the involved movement are difficult to identify with the naked eye. Also, the usage of high processing optometric motion capture system is expensive and causes computational burden. Therefore, this paper suggests the development of a sensorized glove using flex sensor to measure a badminton player’s finger flexion angle. The proposed Hand Monitoring Module (HMM) is connected to a personal computer through Bluetooth to enable wireless data transmission. The usability and feasibility of the HMM to identify different grip types were examined through a series of experiments, where the system exhibited 70% detection ability for the five different grip type. The outcome plays a major role in training players to use the proper grips for a badminton stroke to achieve a more powerful and accurate stroke execution.

In the automotive industry, there are many assembly processes that require a high geometric accuracy, in the micrometer range; generally open-loop controllers cannot meet these requirements. This results in an increased defect rate and high production costs. This paper presents an experimental study of interference fit process, aimed to evaluate the aspects which have the most impact on the uncertainty in the final positioning. The press-fitting process considered, consists in a press machine operating with a piezoelectric actuator to press a plug into a sleeve. Plug and sleeve are designed and machined to obtain a known interference fit. Differential displacement and velocity measurements of the plug with respect to the sleeve are measured by a fiber optic differential laser Doppler vibrometer. Different driving signals of the piezo actuator allow to have an insight into the differences between a linear and a pulsating press action. The paper highlights how the press-fit assembly process is characterized by two main phases: the first is an elastic deformation of the plug and sleeve, which produces a reversible displacement, the second is a sliding of the plug with respect to the sleeve, which results in an irreversible displacement and finally realizes the assembly. The simultaneous measurements of the displacement and the force have permitted to define characteristic features in the signal useful to identify the start of the irreversible movement. These indicators could be used to develop a control logic in a press assembly process.

The purpose of this paper is to solve two fundamental tasks, i.e., to design the pipeline model with sufficient adequacy and reproducibility, and to solve the inverse problem for the transition from the experimental data on the magnetic field in the measurement area directly to the pipeline characteristics, which are necessary for mapping pipes location and finding coordinates of welds. The paper presents a mathematical ideal pipeline model in the geomagnetic field without considering the pipe material. The solution of the direct and inverse problems are described, and the directions of the model development and methods of data interpretation are presented.

In this work, an optimal control (under constraints) based on the Pontryagin’s maximum principle is used to optimally manage energy flows in a basic PEM (Proton Exchange Membrane) fuel cells system associated to lithium-ion batteries and supercapacitors through a common DC bus having a voltage to stabilize using the differential flatness approach. The adaptation of voltage levels between different sources and load is ensured by use of three DC-DC converters, one boost connected to the PEM fuel cells, while the two others are buck/boost and connected to the lithiumion batteries and supercapacitors. The aim of this paper is to develop an energy management strategy that is able to satisfy the following objectives: –Impose the power requested by a habitat (representing the load) according to a proposed daily consumption profile,–Keep fuel cells working at optimal power delivery conditions,–Maintain constant voltage across the common DC bus,–Stabilize the batteries voltage and stored quantity of charge at desired values given by the optimal control.Results obtained under MATLAB/Simulink environment prove that the cited objectives are satisfied, validating then, effectiveness and complementarity between the optimal and flatness concepts proposed for energy management. Note that this study is currently in experimentally validation within MSE Laboratory.In this work, an optimal control (under constraints) based on the Pontryagin’s maximum principle is used to optimally manage energy flows in a basic PEM (Proton Exchange Membrane) fuel cells system associated to lithium-ion batteries and supercapacitors through a common DC bus having a voltage to stabilize using the differential flatness approach. The adaptation of voltage levels between different sources and load is ensured by use of three DC-DC converters, one boost connected to the PEM fuel cells, while the two others are buck/boost and connected to the lithiumion batteries and supercapacitors. The aim of this paper is to develop an energy management strategy that is able to satisfy the following objectives: –Impose the power requested by a habitat (representing the load) according to a proposed daily consumption profile,–Keep fuel cells working at optimal power delivery conditions,–Maintain constant voltage across the common DC bus,–Stabilize the batteries voltage and stored quantity of charge at desi...

In this paper, we numerically investigate CdTe/CdS PV cell properties using a simulation program Solar Cell Capacitance Simulator in 1D (SCAPS-1D). A simple structure of CdTe PV cell has been optimized to study the effect of temperature, absorber thickness and work function at very low incident power. Objective of this research paper is to build an efficient and cost effective solar cell for portable electronic devices such as portable computers and cell phones that work at low incident power because most of such devices work at diffused and reflected sunlight. In this report, we simulated a simple CdTe PV cell at very low incident power, which gives good efficiency.

The given paper studies the effect of surface laser treatment of WC-Co coatings on their surface morphology, phase composition and thermal cycling behavior. The coatings were sprayed on stainless steel substrates with the use of a high velocity oxy fuel spraying process. Application of the scanning electron microscopy and X-ray diffraction showed that re-melting of the coating surface layer during laser treatment induced changes in its phase composition as well as the formation of regular rows of globular asperities on the coating surface. The latter resulted in a sharp increase in thermal shock resistance of the laser treated WC-Co coatings under water quench tests; its underlying mechanism are proposed and discussed in the paper.

Design and simulation of an axial flux permanent magnet generator (AFPMG) have been described in this paper. It was designed using the single rotor – single stator construction. The analytical method was using in the design process. The design process also employed the simulation using Finite Element Method Magnetics (FEMM) 4.2 software for identifying the magnetic characteristic and heat transfer. The effect of fill factor (FF) variation on the generator performances also observed in this paper. The design result shows that using the selected FF, the conductor diameter, power output, efficiency and heat distribution are affected but not for the Bg. The generator output can achieve up to 5.2 kW using the FF 0.4 which is more than assumed power output at the pre-design using FF 0.3. It also can be seen that the increasing FF will increase the power output and the efficiency. Despite a higher temperature compared with FF 0.3 and 0.35, the value of 0.4 is the most appropriate FF for designing the AFPMG.

Permanent magnet bearings (PMB) are contact free bearings which utilize the forces generated by the magnets. PMB in this work is a type of radial PMB, which functions as the radial bearings of the Horizontal Axis Wind Turbine (HAWT) rotor shaft. Radial PMB should have a greater radial force than the radial force HAWT rotor shaft (bearing load). This paper presents a modeling and experiments to calculate the radial force of the radial PMB. This paper also presents rotational speed test of the radial PMB compared to conventional bearings for HAWT applications. Modeling using COMSOL Multiphysics 4.3b with the magnetic fields physics models. Experiments were conducted by measuring the displacement of the rotor to the stator for a given load variation. Results of the two methods showed that the large displacement then the radial force would be greater. Radial forces of radial PMB is greater than radial forces of HAWT rotor shaft. The rotational speed test results of HAWT that used radial PMB produced higher ro...

Concentrating solar power co-generation systems have been identified as potential stand-alone solar energy supply solutions in remote rural energy applications. This study describes the modelling and synthesis of a combined heat and power Stirling CSP system in order to evaluate its potential performance in small off-grid rural village applications in Africa. This Stirling micro-Combined Heat and Power (micro-CHP) system has a 1 kW electric capacity, with 3 kW of thermal generation capacity which is produced as waste heat recovered from the solar power generation process. As part of the development of an intelligent microgrid control and distribution solution, the Trinum micro-CHP system and other co-generation systems are systematically being modelled on the TRNSYS simulation platform. This paper describes the modelling and simulation of the Trinum micro-CHP configuration on TRNSYS as part of the process to develop the control automation solution for the smart rural microgrid in which the Trinum will serve as a solar powerpack. The results present simulated performance outputs for the Trinum micro-CHP system for a number of remote rural locations in Africa computed from real-time TRNSYS solar irradiation and weather data (yearly, monthly, daily) for the relevant locations. The focus of this paper is on the parametric modelling of the Trinum Stirling micro-CHP system, with specific reference to this system as a TRNSYS functional block in the microgrid simulation. The model is used to forecast the solar energy harvesting potential of the Trinum micro-CHP unit at a number of remote rural sites in Africa.

Presented paper performs an analysis of quadrature signal processing algorithms for high demanding laser interferometry applications. Careful signal processing is required to minimize nonlinearities which come from optical path and components’ imperfections, and reduce overall instrumental error. Paper focuses on algebraic fits, because implementation for real time systems was a main requirement. The most demanding applications are stationary measurements where the position slightly fluctuates in the range below one fringe period. Therefore, analysis was performed for samples that were spread along a few milliradians of a full circle.

SIDON (SImulator of raDiO-frequency Networks) is an in-house developed Radio-Frequency (RF) network solver that has been implemented to cross-validate the design of WEST ICRF launchers and simulate their impedance matching algorithm while considering all mutual couplings and asymmetries. In this paper, the authors illustrate the theory of SIDON as well as results of its calculations. The authors have built time-varying plasma scenarios (a sequence of launchers front-faces L-mode and H-mode Z-matrices), where at each time step (1 millisecond here), SIDON solves the RF network. At the same time, when activated, the impedance matching algorithm controls the matching elements (vacuum capacitors) and thus their corresponding S-matrices. Typically a 1-second pulse requires around 10 seconds of computational time on a desktop computer. These tasks can be hardly handled by commercial RF software. This innovative work allows identifying strategies for the launchers future operation while insuring the limitations on the currents, voltages and electric fields, matching and Load-Resilience, as well as the required straps voltage amplitude/phase balance. In this paper, a particular attention is paid to the simulation of the launchers behavior when arcs appear at several locations of their circuits using SIDON calculator. This latter work shall confirm or identify strategies for the arc detection using various RF electrical signals. One shall note that the use of such solvers in not limited to ICRF launchers simulations but can be employed, in principle, to any linear or linearized RF problem.

This paper presents using of FlightGear application for flight simulation of a mini-UAV (Unmanned Aerial Vehicle). The first part of the paper is about general information of UAVs and about the fundamentals of airplane flight mechanics. The main section summarizes the information about FlightGear application and describes a way of using the application to simulate a mini-UAV. The process of altitude change by using autopilot has been simulated. In the created simulation, three stage cascade controller was used for an altitude control. Heading was controlled by 2 stage cascade PID (Proportional-Integral-Derivative) controller. An automatic throttle system was applied for a velocity control. The setting of all controllers is included in the description of the simulation. Finally, the results of FlightGear simulation are discussed.

The paper presents the weight optimization process of the main steel truss that supports the Slatina Sport Hall roof. The structure was loaded with self-weight, dead loads, live loads, snow, wind and temperature, grouped in eleven load cases. The optimization of the structure was made using genetic algorithms implemented in a Matlab code. A total number of four different cases were taken into consideration when trying to determine the lowest weight of the structure, depending on the types of connections with the concrete structure ( types of supports, bearing modes), and the possibility of the lower truss chord nodes to change their vertical position. A number of restrictions for tension, maximum displacement and buckling were enforced on the elements, and the cross sections are chosen by the program from a user data base. The results in each of the four cases were analyzed in terms of weight, element tension, element section and displacement. The paper presents the optimization process and the conclusions drawn.

The increasing use of renewable energy technologies for electricity generation, many of which have an unpredictably intermittent nature, will inevitably lead to a greater demand for large-scale electricity storage schemes. For example, the expanding fraction of electricity produced by wind turbines will require either backup or storage capacity to cover extended periods of wind lull. This paper describes a recently proposed storage scheme, referred to here as Pumped Thermal Storage (PTS), and which is based on “sensible heat” storage in large thermal reservoirs. During the charging phase, the system effectively operates as a high temperature-ratio heat pump, extracting heat from a cold reservoir and delivering heat to a hot one. In the discharge phase the processes are reversed and it operates as a heat engine. The round-trip efficiency is limited only by process irreversibilities (as opposed to Second Law limitations on the coefficient of performance and the thermal efficiency of the heat pump and heat engine respectively). PTS is currently being developed in both France and England. In both cases, the schemes operate on the Joule-Brayton (gas turbine) cycle, using argon as the working fluid. However, the French scheme proposes the use of turbomachinery for compression and expansion, whereas for that being developed in England reciprocating devices are proposed. The current paper focuses on the impact of the various process irreversibilities on the thermodynamic round-trip efficiency of the scheme. Consideration is given to compression and expansion losses and pressure losses (in pipe-work, valves and thermal reservoirs); heat transfer related irreversibility in the thermal reservoirs is discussed but not included in the analysis. Results are presented demonstrating how the various loss parameters and operating conditions influence the overall performance.

Digital radiography has made its way into in-the-field girth weld testing. With recent generations of detectors and x-ray tubes it is possible to reach the image quality desired in standards as well as the speed of inspection desired to be competitive with film radiography and automated ultrasonic testing. This paper will show the application of these technologies in the RTD Rayscan system. The method for achieving an image quality that complies with or even exceeds prevailing industrial standards will be presented, as well as the application on pipeline girth welds with CRA layers. A next step in development will be to also achieve a measurement of weld flaw height to allow for performing an Engineering Critical Assessment on the weld. This will allow for similar acceptance limits as currently used with Automated Ultrasonic Testing of pipeline girth welds. Although a sufficient sizing accuracy was already demonstrated and qualified in the TomoCAR system, testing in some applications is restricted to time limits. The paper will present some experiments that were performed to achieve flaw height approximation within these time limits.

A classical MEMS gyro transforms angular rates into electrical values through Euler's equations of angular rotation. Production models of a MEMS gyroscope will have manufacturing errors in the coefficients of the differential equations. The output signal of a production gyroscope will be corrupted by noise, with a major component of the noise due to the manufacturing errors. As is the case of the components in an analog electronic circuit, one way of controlling the variability of a subsystem is to impose extremely tight control on the manufacturing process so that the coefficient values are within some specified bounds. This can be expensive and may even be impossible as is the case in certain applications of micro-electromechanical (MEMS) sensors. In a recent paper [2], the authors introduced a method for combining the measurements from several nominally equal MEMS gyroscopes using a technique based on a concept from electronic circuit design called dynamic element matching [1]. Because the method in this paper deals with systems rather than elements, it is called a dynamic system matching technique (DSMT). The DSMT generates a single output by randomly switching the outputs of several, nominally identical, MEMS gyros in and out of the switch output. This has the effect of 'spreading the spectrum' of the noise caused by the coefficient errors generated in the manufacture of the individual gyros. A filter can then be used to eliminate that part of the spread spectrum that is outside the pass band of the gyro. A heuristic analysis in that paper argues that the DSMT can be used to control the effects of the random coefficient variations. In a follow-on paper [4], a simulation of a DSMT indicated that the heuristics were consistent. In this paper, analytic expressions of the DSMT noise are developed which confirm that the earlier conclusions are valid. These expressions include the various DSMT design parameters and, therefore, can be used as design tools for DSMT systems.

The pulsed eddy current (PEC) technique generates responses over a wide range of frequencies, containing more spectral coverage than traditional eddy current inspection. Eddy current pulsed thermography (ECPT), a newly developed non-destructive testing (NDT) technique, has advantages such as rapid inspection of a large area within a short time, high spatial resolution, high sensitivity and stand-off measurement distance. This paper investigates ECPT for the evaluation of gear fatigue tests. The paper proposes a statistical method based on single channel blind source separation to extract details of gear fatigue. The discussion of transient thermal distribution and patterns of fatigue contact surfaces as well as the non-contact surfaces have been reported. In addition, the measurement for gears with different cycles of fatigue tests by ECPTand the comparison results between ECPT with magnetic Barkhausen noise (MBN) have been evaluated. The comparison shows the competitive capability of ECPT in fatigue evaluation.

Jet pumps are widely used in thermoacoustic Stirling heat engines and pulse tube cryocoolers to eliminate the effect of Gedeon streaming. The resistance properties of jet pumps are principally influenced by their structures and flow regimes which are always characterized by Reynolds numbers. In this paper, the jet pump of which cross section contracts abruptly is selected as our research subject. Based on linear thermoacoustic theory, a CFD model is built and the oscillating flow of the working gas is simulated and analyzed with different Reynolds numbers in the jet pump. According to the calculations, the influence of different structures and Reynolds numbers on the resistance properties of the jet pump are analyzed and presented. The results show that Reynolds numbers have a great influence on the resistance properties of jet pumps and some empirical formulas which are widely used are unsuitable for oscillating flow with small Reynolds numbers. This paper provides a more comprehensive understanding on resistance properties of jet pumps with oscillating flow and is significant for the design of jet pumps in practical thermoacoustic engines and refrigerators.

The preliminary assessment of a Lower Hybrid Current Drive (LHCD) system for the DEMOnstration power plant (DEMO) is mainly focused on the R&D needs of the less conventional RF components of the Main Transmission Line (MTL) and of the launcher. 500 kW, CW klystrons will be used to deliver the RF power to independent Passive Active Multijunction (PAM) launcher modules at 5 GHz. This paper describes the criteria followed to investigate the optimum solution for the RF window used as vacuum barrier between the MTL and the launcher, an open issue in the LHCD system for ITER too. The best candidate, capable of withstanding a power level of, or above, 0.5 MW in CW operation and to satisfy the electrical and thermonuclear requirements, is a Pill-Box assembly, based on a thin single disk of CVD-diamond as dielectric, water cooled at the edge. A thickness of 3 mm, much shorter than half a wavelength of the TE°11 mode in the dielectric as in the conventional window (unfeasible and too expensive with CVD-diamond at these frequencies), is sufficient to limit the exerted stress at the edge under the fracture stress for a maximum pressure applied of 0.9 MPa. In this paper the simulation results of conventional and thin CVD-diamond vacuum windows are presented comparing S-parameters, losses and electric fields in both matching condition and with VSWR = 2, using WR284 and WR229 as input/output rectangular waveguide. © 2014 American Institute of Physics.

One of the still open problems in the inspection research concerns the determination of the maximum depth to which a surface defect goes. Eddy current testing being one of the most sensitive well established inspection methods, able to detect and characterize different type of defects in conductive materials, is an adequate technique to solve this problem. This paper reports a study concerning the disturbances in the magnetic field and in the lines of current due to a machined linear defect having different depths in order to extract relevant information that allows the determination of the defect characteristics. The image of the eddy currents (EC) is paramount to understand the physical phenomena involved. The EC images for this study are generated using a commercial finite element model (FLUX). The excitation used produces a uniform magnetic field on the plate under test in the absence of defects and the disturbances due to the defects are compared with those obtained from experimental measurements. In order to increase the limited penetration depth of the method giant magnetoresistors (GMR) are used to lower the working frequency. The geometry of the excitation planar coil produces a uniform magnetic field on an area of around the GMR sensor, inducing a uniform eddy current distribution on the plate. In the presence of defects in the material surface, the lines of currents inside the material are deviated from their uniform direction and the magnetic field produced by these currents is sensed by the GMR sensor. Besides the theoretical study of the electromagnetic system, the paper describes the experiments that have been carried out to support the theory and conclusions are drawn for cracks having different depths.

Tore Supra is dedicated to long pulse operation at high power, with a record in injected energy of 1 GJ (2.8 MW × 380 s) and an achieved capability of 12 MW injected power delivered by 3 RF systems: Lower Hybrid Current Drive (LHCD), Ion Cyclotron Resonance Heating (ICRH) and Electron Cyclotron Resonance Heating (ECRH). The new WEST project (W [tungsten] Environment in Steady-state Tokamak) aims at fitting Tore Supra with an actively cooled tungsten coated wall and a bulk tungsten divertor. This new device will offer to ITER a test bed for validating the relevant technologies for actively cooled metallic components, with D-shaped H-mode plasmas. For WEST operation, different scenarii able to reproduce ITER relevant conditions in terms of steady state heat loads have been identified, ranging from a high RF power scenario (15 MW, 30 s) to a high fluence scenario (10 MW, 1000 s). This paper will focus on the evolution of the RF systems required for WEST. For the ICRH system, the main issues are its ELM resilience and its CW compatibility, three new actively cooled antennas are being designed, with the aim of reducing their sensitivity to the load variations induced by ELMs. The LH system has been recently upgraded with new klystrons and the PAM antenna, the possible reshaping of the antenna mouths is presently studied for matching with the magnetic field line in the WEST configuration. For the ECRH system, the device for the poloidal movement of the mirrors of the antenna is being changed for higher accuracy and speed.Tore Supra is dedicated to long pulse operation at high power, with a record in injected energy of 1 GJ (2.8 MW × 380 s) and an achieved capability of 12 MW injected power delivered by 3 RF systems: Lower Hybrid Current Drive (LHCD), Ion Cyclotron Resonance Heating (ICRH) and Electron Cyclotron Resonance Heating (ECRH). The new WEST project (W [tungsten] Environment in Steady-state Tokamak) aims at fitting Tore Supra with an actively cooled tungsten coated wall and a bulk tungsten divertor. This new device will offer to ITER a test bed for validating the relevant technologies for actively cooled metallic components, with D-shaped H-mode plasmas. For WEST operation, different scenarii able to reproduce ITER relevant conditions in terms of steady state heat loads have been identified, ranging from a high RF power scenario (15 MW, 30 s) to a high fluence scenario (10 MW, 1000 s). This paper will focus on the evolution of the RF systems required for WEST. For the ICRH system, the main issues are its ELM resil...

Digital Shearography is a laser based inspection method, capable of determining minute surface displacement gradients in response to an applied stress. The non-contacting technique is based on interferometric principles, and produces whole field results. As a result the method has been adapted for defect detection purposes of high value components in the NDT/E industry. In order to obtain an object’s surface displacement gradient when applying Digital Shearography, the object has to be stressed. This paper investigates the use of vibration excitation as a stressing technique for the inspection of selected composite aircraft components. The theory of digital Shearography is presented, the inspections using a piezo based vibration probe is outlined, and the results obtained are displayed. A discussion of the results obtained concludes the paper.

Infrastructure health monitoring is an important issue in the transportation industry. For the case of cement-based structures in particular, detection of corrosion on reinforcing steel bars (rebar) is an ongoing problem for aging infrastructure. There have been a number of techniques that have shown promise in this area including microwave nondestructive testing (NDT) and thermography. Thermography is quite advantageous as it is an established method, and can be utilized for large inspection areas with intuitive results. Typical heat sources include induction heating and flash lamps, but these are not without drawbacks. Microwave nondestructive testing has also been successful at detecting corroded rebar, but at the cost of lengthy scan times. This paper presents an investigation into the potential of utilizing aspects of microwave NDT and thermography to create a hybrid NDT method, herein referred to as Active Microwave Thermography (AMT). AMT takes advantage of the electromagnetically lossy nature of corrosion byproducts and uses microwave energy to induce heat in the corrosion. Subsequently, the resultant heat profile is captured using an infrared camera. This paper presents initial simulations and measurements that highlight the potential of AMT to detect corroded rebar.

We showed our work on modeling turbine blade crack detection in Sonic Infrared (IR) Imaging with a method of creating flat crack surface in finite element analysis (FEA) in last year's QNDE paper. This modeling has been carried out continuously as part of model-assisted study on crack detection in aircraft engine turbine blades. We have presented that Sonic IR Imaging NDE is a viable method to detect defects in various structures. It combines ultrasound excitation for frictional heating in defects and infrared imaging to sense this heating, and thus to identify the defects. It is a fast wide-area imaging technology. It only takes a second to image a large area of a target sample. When an aircraft is in flight, the turbine engine blades operate under high temperature and high cyclic stresses. Thus, fatigue cracks can form after many hours of operation. Sonic IR Imaging can be used to detect such cracks. However, we still need to better understand contributions of parameters/factors in the crack detection process with Sonic IR Imaging. FEA modeling can help us to reveal certain aspects through the data it produces where experimental work cannot achieve. Upon the model we presented last year, a two-step simulation process was designed to simulate the important aspects in our experiments. These include a newly designed model for the ultrasound transducer which delivers mechanical energy to the sample and the implementation of static force while engaging the transducer to the sample. In this paper, we present the ideas and the results from the new model.

Thermal Barrier Coatings (TBC) are used to reduce the working temperature of the high pressure turbine blade metal surface and hence permit engines to operate at higher temperatures/ efficiencies. A sensor TBC is an adaptation of existing TBCs to enhance their functionality, such that they become sensors and allow measurement of component temperatures. The sensing capability is introduced by embedding optically active materials into the TBC and by illuminating these coatings with excitation light phosphorescence can be observed. The phosphorescence carries temperature and structural information about the coating. This paper describes the first ever implementation of a sensor coating system on a full-scale jet engine. The system consists of three main components: industrially manufactured coatings, advanced remote detection optics with large stand-off distances and tailored control and readout software. The majority of coatings were based on yttrium stabilized zirconia doped with Dy and Eu, although other coatings were manufactured, too. Coatings were produced on a production line using atmospheric plasma spraying. An advanced optical system was designed, manufactured and operated permitting scanning of coated components using a wide acceptance angle. Successful measurements were taken from the nozzle guide vanes at the inlet to the turbine section and are reported in the paper.

This paper identifies the influence variables affecting the resolution of thermometry resistance bridges. The theoretical limit to the resolution is determined by the spectral density of all noise sources, including the thermal noise from the resistors and amplifiers, quantization noise, and the equivalent noise bandwidth. Optimization of resolution is equivalent to minimization of measurement time, which has a Heisenberg-uncertainty-like relationship with equivalent noise bandwidth. Bridge design has a major influence on the compromises between the different noise sources, as well as influencing compromises with respect to measurement time. The paper explains the concept of an ideal averaging filter and illustrates the use of the Allan variance to evaluate the dependence of the resolution on measurement time.

This paper presents a simple way to form non-diffracting narrow beams, also called bessel beams, with phased arrays. Normally non-diffracting beams are generated by using axiconi-cal lenses. The axiconical lens is simulated by phased array ultrasonic technique using a delay time distribution that is chosen according to the sound path in axiconical lenses. The phased array probe is a 2D matrix array with 121 elements. Each element is driven by another delay time. The delay times which are usually used for this probe to focus in different depth of the material are distributed spherical-ly over the area of the probe. To form a non-diffracting beam the distribution of the time delays is linearly increasing to the center of the probe. In the paper the results of the simulation are given. By varying the parameters in the simulation the best setting is chosen. With this an experiment is done and the expe-rimental results are compared to the simulation results. Considerations on the best probe to form non-diffracting beams with phased array are described.

The aim of this paper is to study the mechanical capacity improvement in a cold formed steel cross section with thickness of 1 mm regards to a cross section made by means of hot-rolled steel with thickness of 4 mm, respectively. Likewise, the differences are studied in the manufacturing processes used in both profiles, and the particularities of cold formed steel cross section. This paper analyzes temperature, stress and deformations using Element Method DEFORM software. This research has been focused in the study of accumulation points of stress to verify the behavior of the sheet of cold formed steel during the folded process. Stress of the steel cross section has been analyzed during the folded process, showing instant step of simulation. Conclusions show how these points of stress concentration could be an influence during the manufacturing process.

Shipbuilding processes involve highly dangerous manual welding operations. Welding of ship hulls presents a hazardous environment for workers. This paper describes a new robotic system, developed by the SHIPWELD consortium, that moves autonomously on the hull and automatically executes the required welding processes. Specific focus is placed on the trajectory control of such a system and forms the basis for the discussion in this paper. It includes a description of the robotic hardware design as well as some methodology used to establish the torch trajectory control.

The analysis of energy flow is a useful method for understanding a system. This paper focuses on the instantaneous measurement of physical conditions and analysis of energy flow in the Stirling-type pulse tube refrigerator. For measuring physical conditions of the working fluid such as the mass flow rate, the temperature, and the pressure, several cryogenic sensors are installed in the Stirling-type pulse tube refrigerator optimally designed in the operating condition of 60 Hz and 2.5 MPa. The physical conditions of the working fluid in the Stirling-type pulse tube refrigerator are carefully measured as varying the operating frequency and the charging pressure. From the measured results, the enthalpy, the PV work, and the loss are quantified in each location of the PTR and the conversion of energy flows is experimentally confirmed. The results of this paper can be used for understanding the optimal operating condition and modifying correlations of various losses in the Stirling-type pulse tube refrigerato...