bluuebunny/crossref_metadata_2025 huggingface dataset:
Toolpath Planning and Simulation for Cutting Test of Non-Orthogonal Five-Axis Machine Tool
Authors: Lee Jeng Nan , She Chen Hua , Huang Chyouh Wu Brian , Chen Hung Shyong , Kung Huang Kuang
Published: August 2014

Owing to NAS 979 describes a cutting test for five-axis machine center with a universal spindle, several conditions for C-type machine tool have not been defined yet. This paper proposes a cutting test for a non-orthogonal swivel head and a rotary table type five-axis machine tool (C type) to evaluate its performance. The workpiece consists of 10 machining features. These features include the multi-axis simultaneous machining patterns and the positioning machining patterns. The flat end mill cutters are applied in each machining feature. Cutter location data for the test piece was generated using a commercial CAD/CAM system (UG) and converted to five-axis NC code using a postprocessor created in UG Post Builder. This UG postprocessor is verified through the developed postprocessor utilizing the modified D-H notation. It is also verified using VERICUT® solid cutting simulation software demonstrated the veracity of the generated five-axis NC code. The machining test is applicable for a variety of five-axis machine tool configurations.
Microlens Array Fabrication by 3D Diffuser Lithography for Light Enhancement of Organic Light-Emitting Devices
Authors: Lin Hung Yi , Sun Yong Shan , Chen Shih Liang , Wei Mao Kuo
Published: August 2014

Microlens arrays have been fabricated by 3D diffuser lithography in this study. The method mainly adopts two kinds of diffuser films with different transmittances and hazes, integrated by photolithography, polydimethylsiloxane (PDMS) molding and UV forming techniques, to get microlens arrays with different parameters and geometries. The features, such as height, geometry and fill factor of microlens arrays, are controlled by photolithography, using a photomask with circular holes and different exposure doses. The microlens arrays can also be duplicated and transferred to the surface of flexible polyethylene terephthalate (PET) substrate through PDMS molding and UV forming processes. Finally, the outcoupling efficiency of microlens arrays attached to organic light-emitting devices (OLEDs) can be measured and analyzed. More than 60% enhancement of luminous current efficiency can be obtained in experimental results.
Complex Trajectory Planning for Lapping of Diamond Cutting Tool
Authors: Yang Ning , Li Zeng Qiang , Zong Wen Jun , Sun Tao
Published: August 2014

The practice shows that complex lapping motion trajectory can decrease the adverse effects caused by the lapping direction which has a great influence on the lapping of the natural single crystalline diamond cutting tool. For example, addition of a reciprocating motion can get better lapping performance and surface roughness. On some kinds of natural diamond cutting tool lapping machines a further improvement is made by designing an additional planetary spindle to provide planetary motion to the main shaft, which offers a more complex motion trajectory. With an increase in degrees of freedom of the lapping machine, it becomes difficult for technicians to master a good suit of motion process parameters. This paper proposes a set of methods to plan the lapping trajectory with respect to the machine that can perform complex lapping motion. Firstly, the proposed method designed a statistical parameter which is the variance of the direction angle distribution for the lapping velocity and its calculation method to evaluate the complexity of the trajectory. And then the multi-body kinematics model was established by using Simulink tool box in Matlab software for the purpose of model kinematics simulation and outputting data for calculation of the statistical parameter above. Finally, the genetic algorithm was used to find the best motion parameters of every shaft under certain restrictions. The advantage of the set of lapping trajectory planning method presented in this paper is that it combines the powerful multi-body simulation and signal processing ability of Simulink tool box and the characteristics of the genetic algorithm in almost no limitation on awaiting optimization function and suitable for complicated problems. So the method provides not only a way for planning complex diamond lapping trajectory but also a general approach to solve the problem on machine motion process parameters optimization.
Modeling of Vertical Micro Grinding
Authors: Perveen Asma , Rahman M. , Wong Y.S.
Published: August 2014

Due to the small feed rate used in micro-machining, ploughing force needs to be considered in addition to the chip formation force. A new analytical model has been proposed to calculate cutting forces of micro-grinding process based on the process configuration, work piece material properties, and micro-grinding tool topography. The proposed approach allows the calculation of cutting force comprising both the chip formation force and ploughing forcec considering single grain interaction.
Study on the Key Parameters in Etching of Fused Silica Using Atmospheric Inductively Coupled Plasma
Authors: Xin Qiang , Wang Bo , Jin Hui Liang , Li Na , Li Duo , Li Guo
Published: August 2014

Atmospheric Pressure Plasma Processing (APPP) of silicon-based optics and wafers is a form of chemical etching technology developed in recent years. The material removal rate is comparable to those of conventional mechanical processing methods in precision fabrication. Moreover, there is no mechanical contact or physical loading on the substrate surface, hence no surface or sub-surface damages are induced. Inductively coupled plasma is one realization of APPP. In this work, inductively coupled plasma torch is used to generate plasma and excite etchant particles at atmospheric pressure. These active particles then diffused to the workpiece surface, react with its atoms to form volatile products. The activity and number of particles in plasma are influenced by processing parameters such as input power, distance between nozzle and substrate surface, flow rate of plasma gas argon and precursor gas CF4. These factors have various impacts on material removal rate. Processing experiments are conducted on fused silica to investigate the parameters’ influences on material removal rate. The basic interaction between substrate surface and plasma is illustrated, then the relationships between processing parameters and material removal rate are analyzed. From the experiments some trends are derived. Material removal rate rises with the increase of power and flow rate of CF4, whereas decreases with the increase of processing distance, etc. The etching footprint is proved to be near Gaussian-shaped and believed to have high potential for deterministic surface processing.
Automated Bin-Picking with Active Vision
Authors: Chang Wen Chung , Wu Chia Hung
Published: August 2014

In this research, an automated robotic bin-picking system employing active vision for picking up randomly distributed plumbing parts is presented. This system employs an actively-controlled single eye-in-hand system to observe structured light projected onto a set of plumbing parts in a bin. By using image processing and iterative closest point (ICP) algorithms, a single plumbing part that could possibly be taken from the bin is detected. Specifically, by projecting stationary structured light patterns onto the set of plumbing objects, the features on the surfaces of plumbing parts can be reconstructed by actively moving the eye-in-hand camera while performing visual tracking of those features. An effective 3D segmentation technique is employed to extract the point cloud of a single plumbing part that can possibly be grasped successfully. Once the object point cloud is obtained, one needs to determine the coordinate transformation from the end-effector to the selected plumbing part for grasping motion. With the point cloud matching result based on utilizing the ICP algorithm, the position and orientation of the selected plumbing part can be correctly estimated if the deviation of the object point cloud from the model point cloud is small. The control command can thus be given to the robotic manipulator to accomplish the automated bin-picking task. To effectively expand the allowed deviation of the object point cloud, an approximate pose estimation algorithm is employed before performing the ICP algorithm. The proposed approach can virtually estimate any pose of the plumbing part and has been successfully experimented with an industrial manipulator equipped with eye-in-hand single-camera vision and a LCD projector fixed in the work space demonstrating the feasibility and effectiveness. The proposed automated bin-picking system appears to be cost-effective and have great potentials in industrial factory automation applications.
Electro Discharge Machining of AL2O3 Based Ceramic
Authors: Elmenshawy S.K. , Younes Mohammad A. , El-Hofy Hassan
Published: August 2014

Products such as parts of die sets and cutting tool inserts are normally produced with complex shapes in materials of high hardness and wear resistance such as ceramics. Electro discharge machining (EDM) can be used to manufacture complex shapes in high hardness materials, but the material should be conductive. Being conductive, Aluminum oxide (Al2O3) based ceramics represent a good alternative for manufacturing hard complex shape parts. However, the integrity of the produced surfaces and the material removal rate need to be investigated. A full factorial experimental design was used to investigate the effect of some selected process variables, namely; pulse-on time, pulse-off time, and pulse current on specific EDM performance measures. The considered performance measures are; crater diameter (D), material removal rate (MRR), and average roughness value (Ra). An analysis of variance (ANOVA) test was carried out to evaluate the experimental results. Empirical models have been developed using DESIGN EXPERT V.8 to predict the average crater diameter (D), material removal rate (MMR), and average roughness value (Ra). Machining conditions that should result in optimum process performance measures have also been considered.
Technology Evolution of Lower Extremity Exoskeleton from the Patent Perspective
Authors: Lai Rong Jer , Li Min Fang
Published: August 2014

Lower extremity exoskeleton is a mechanical device mainly for augmenting the performance of a healthy person or assisting the people with lower limb pathology. In this study technology evolution of lower extremity exoskeletons was analyzed from the patent perspective. Patent citation analysis based on a specific patent issued by USPTO in 2011 was carried out to trace the evolution of technology concepts in the past four decades. The technologies of control system, sensor, actuator and mechanism applied were compared from the viewpoint of hip, knee and ankle movement, and the most or relatively more cited patents were selected as the representatives of technology. Several trends of design concept with respect to the hip, knee and ankle movement were presented in the paper. For example, for the design of subsystem hip joint, the considerations were taken gradually from prevention of subluxation or dislocation of hip joint alone at the early days to reducing metabolic energy associated with walking/running as well as reducing the incidence of falls caused by the insufficient leg thrust recently. For the design of subsystem knee joint, articulated splints with hinge pivot, articulate notch or spring at the beginning were replaced by the piston and cylinder assemblies with adjustable valves to resist the flexion and extension of the joint, and later by the damping member with control unit for detecting the force, knee angle and acceleration.
Characteristics of Electrical Discharge Machining in a Working Fluid Mixed with Micro-Bubbles
Authors: Takezawa Hideki , Suzuki Kiichi , Mohri Naotake
Published: August 2014

Electrical discharge machining (EDM) is a process of removing material by electric discharge in an insulating working fluid. The material is melted by discharge, the material is thought to blown off by the vaporizing explosion of the working fluid. The removal of the material is affected by the expansion and contraction of a bubble. When the power of the vaporizing explosion is large, the amount of material removed increases, and surface roughness decreases. However, when the power of the vaporizing explosion is small, the amount of material removed decreases and surface roughness increases. The power of the vaporizing explosion is determined by the input energy, and the amount of material removed is determined by the degree of the power of the vaporizing explosion. This study considers the changes in the characteristics of EDM by using a working fluid mixed with micro-bubbles. A micro-bubble is defined as a bubble having a diameter of less than or equal to 50 μm. They have special characteristics of causing an increase in the interior gas pressure, resulting in an increase in ion concentration around the gas–water interface. The vaporizing explosion seems to be weakened by the use of a working fluid mixed with micro-bubbles, and surface roughness seems to be improved. Therefore, we performed EDM using pure water and a micro-bubble mixed fluid to clarify the characteristics of EDM.
Edge Effect and Compensation Method Research of the Template Electrochemical Etching
Authors: Wei Hong Yu , Guo Zhong Ning , Wang Guan
Published: August 2014

Uniformity is an important index of the template electrochemical etching. Due to the uneven current distribution between the two electrodes, the etching depth of the workpiece center and edge are significantly different,and the deviation of which is up to 15% or more. In this study, the causes of edge effect is analyzed. A compensation method is proposed and proved by experiments.The results show that: this method is simple, and the uniformity can be reduced to about 3%. It is suitable for the processing of high uniformity requirements in microstructure machining.
Figuring and Finishing of Reaction-Sintered SiC by Anodic Oxidation Assisted Process
Authors: Shimozono Naoki , Shen Xin Min , Deng Hui , Endo Katsuyoshi , Yamamura Kazuya
Published: August 2014

Reaction-sintered silicon carbide (RS-SiC) is a promising material for optical components used in space, or molds for precision glass lens because of its excellent properties. For processing of RS-SiC, diamond tools are utilized because RS-SiC is difficult-to-machine material due to its high hardness. In that case, subsurface damage (SSD) and scratches are inevitably introduced on the processed surface, and they deteriorate the qualities of products. To resolve these issues, we proposed a complex machining technique named anodic oxidation assisted process (AOAP), in which localized anodic oxidation and removal of the oxidation layer by grinding or polishing were combined, for figuring or polishing of RS-SiC without introducing any scratches and SSD. The grinding or polishing tool used in AOAP has a lower hardness than that of RS-SiC, but higher than that of the oxidation products. It is possible to figure the objective shape and polish the surface by changing the conditions including the oxidation time, the composition of electrolyte, the configuration of the cathode electrode, applied voltage, and so on. In our previous study, we found that RS-SiC was oxidized efficiently by anodic oxidation with various electrolytes such as phosphoric acid, ultrapure water, and a mixture of hydrochloric acid and hydrogen peroxide. In this research, we investigated the preliminary processing characteristics of AOAP for RS-SiC. We ascertained that irradiating UV light with photon energy higher than the band gap of processed materials is very effective for increasing the oxidation rate of anodic oxidation. And we proposed a novel polishing process of RS-SiC, which combining oxidation only SiC area in RS-SiC by anodic oxidation with the electrolyte of ceria slurry, with polishing by ceria slurry which removes both oxidized layer and unoxidized layer in RS-SiC. The results of investigation for the oxidation rate and the polishing rate of SiC, Si and SiO2 with ceria slurry implies that we can remove SiC grain and Si grain in RS-SiC at the same MRR by combing the anodic oxidation and polishing with ceria slurry at the same time, and obtain the smooth surface.
Material Removal Rate Control in Open-Air Type Plasma Chemical Vaporization Machining by Pulse Width Modulation of Applied Power
Authors: Takeda Yoshiki , Hata Yuki , Endo Katsuyoshi , Yamamura Kazuya
Published: August 2014

Plasma chemical vaporization machining (PCVM) is an ultraprecise figuring technique for optical components without introducing the subsurface damage. In our previous study, the material removal volume was controlled by changing the scanning speed of the worktable. However, because of inertia of the worktable, a discrepancy between the theoretical scanning speed and the actual scanning speed will occur if the spatial change rate of speed is rapid. Therefore, we proposed the application of the pulse width modulation (PWM) control and the amplitude modulation (AM) control of the applied RF power to control the material removal rate (MRR). Experimental results showed that the relationship between the MRR and the average RF power had high linearity, the control range of the PWM control mode was from 0.19 x 10-2 mm3/min to 3.90 x 10-2 mm3/min (from 5% to 100%), which was much wider than that of the AM control mode.
Ultrasonically Assisted Micro Drilling for Acrylic Resin μ-TAS
Authors: Hara Keisuke , Asahi Atsushi , Isobe Hiromi
Published: August 2014

Recently, technologies for medical inspection have been increasing rapidly. In biomedical industry, a demand of Micro Total Analysis System (μ-TAS) has been growing which used in automatically inspection for chemical analysis. The μ-TAS have micro passageway which is constructed by many fine micro holes. Final polishing by skilled workers are carried out after drilling to obtain smooth surface of holes. Because new manufacturing technique is required instead of skilled workers, it increases productivity and cost performance of the μ-TAS. Drilling technique with low temperature environment around cutting edge is required to prevent heat crack or adhesion on holes surface, because acrylic resin heats sensitive material. In this study, ultrasonically assisted micro drilling technique is proposed to increase productivity of μ-TAS and quality of micro holes. Ultrasonically assisted machining has effective technique to improve machinability, e.g. reduce cutting force, increase chip removability and machined surface quality. This paper describes the cutting characteristics of ultrasonically assisted micro-drilling for acrylic resin to employ the μ-TAS manufacturing to solve above problems.
Development of a Piezoelectric-Actuated Drop-on-Demand Droplet Generator Using Adaptive Wavelet Neural Network Control Scheme
Authors: Liang Jin Wei , Chen Hung Yi
Published: August 2014

This paper presents the design, fabrication and control of a piezoelectric-type droplet generator which is applicable for on-line dispensing. The piezoelectric-actuated dispensing system consists of a linear piezoelectric motor (LPM) actuated table, a plastic syringe, a nozzle, a linear encoder and a PC-based control unit. Adaptive wavelet neural network (AWNN) control is applied to overcome nonlinear hysteresis inherited in the LPM. The adaptive learning rates are derived based on the Lyapunov stability theorem so that convergence of the tracking error can be assured. Unlike open-loop dispensing system, the system proposed can potentially generate droplets with high accuracy. Experimental verifications including regulating and tracking control are performed firstly to assure the reliability of the proposed control schemes. Real dispensing is then conducted to validate the feasibility of the piezoelectric-actuated drop-on-demand droplet generator. The results demonstrate that the proposed scheme works well in developing the piezoelectric-actuated drop-on-demand dispensing system.
Formation of Aluminum Nitride Films by Gas Nitriding
Authors: Yoshida Masashi , Tao Zhou , Utsumi Noah
Published: August 2014

In this study, aluminum alloys were subjected to nitriding at 823 K for 0–18.0 ks using alumina and magnesium powders for improving their radiation performance. After nitriding, aluminum nitride films were formed on the aluminum substrate. The thickness of the formed films varied from 1.5 to 11 μm, and the color of the film surface was dark brown or black. The thickness of the aluminum nitride film increased with an increase in the treatment time. X-ray diffraction and electron probe microanalysis results showed that the film was composed of aluminum nitride, alumina, aluminum, and magnesium. Further, the film showed good adhesion at 0 ks.
Fabrication and Mechanical Properties of C/C-HfC-SiC Composites
Authors: Yano Yuki , Wada Kazuya , Aoki Takuya , Ogasawara Toshio , Umezu Shinjiro
Published: August 2014

Reusable spacecraft/supersonic aircraft is research and development towards the realization of a new aerospace transportation system.Because these transport aircraft is to flight at a speed of more than Mach 5,are considering the use of scramjet engine.Because this engine uses air as an oxidant and liquid hydrogen as a fuel,the combustion gas temperature is more than 2500°C.So the combustor is required lightweight material and super-heat-resistant material.In the field of aerospace,SiC-based ceramics that is heat-resistant materials are well known as to maintain the mechanical properties at high temperatures and have a high oxidation resistance.However, this material limit as heat-resistant material is about 1600 °C .Therefore, it can not be used in an environment of scramjet engine combustor.There are the measures by metal structure to be force-cooled by refrigerant fuel,but apply is difficult because the system is complexity and very heavy. In this study use the hafnium-based super heat-resistant ceramics that is having a melting point more than 2000°C. Purpose is to develop a new technique for forming the ceramics mainly composed from Hafnium Carbide (Melting point:3950°C) that is very high melting point and have oxidation resistance by melt impregnation to inside C/C composite.In addition, implement the evaluation of changes in the organization after each process by the cross-sectional observation and strength assessment by three-point bending test.
Composite Characterization of Engineering Ceramics Ground Surface
Authors: Qi Zhen Liang , Lin Bin , Zhang Yan Bin , Liang Xiao Hu , Li Xin Yue
Published: August 2014

Traditional methods of roughness characterization cannot properly reflect the characteristics of engineering ceramics surface topography. Therefore, the composite characterization using combined fractal method and wavelet method is introduced in this paper. And they are used to describe the global and local characteristics of engineering ceramics ground surface, respectively. Furthermore, a concept called topography damage ratio is proposed to describe characteristic of the deep wave trough. Finally, 3-D measurement is used to verify this method.
Design Life Analysis of KTX Running Gear Systems on Various Operating Conditions
Authors: Lee Chan Woo , Lee Dong Hyeong
Published: August 2014

The maximum speed of KTX is 305 km/h for commercial service and it is designed to reach 330 km/h. The design fatigue life of KTX running gear systems is 20 years. The mileage per year of KTX train is 600,000 km/year. In other words, the design life of the KTX running gear systems is 12,000,000km. KTX train is designed to be dedicated to driving the high-speed railway. But the KTX train routes that connect with the conventional line and high-speed line service. South Korea’s high-speed railway design maximum speed is 350km/h. Comparison, speed KTX train existing line of service is set to 150km/h, 180km/h and 220km/h, depending on the section. Thus, the value of the maximum torque, torsional stress and bending moments acting on the KTX running gear systems may appear differently from the high-speed line design criteria. Furthermore, the maximum stress/strain acting on the suspension of parts of the running gear system is different. In this study, the actual KTX train to set running gear system design life compared to the actual life, according to the characteristics of the actual service routes were compared and analyzed.
Study of Mechanism for Wear Adjustment with Electro Wedge Brake
Authors: Shin Dong Hwan , Park Tae Sang , Jin Sung Ho , Moon Jeon Il , Yang Seung Han
Published: August 2014

Electro wedge brake (EWB) have been suggested and improved for enhancing the braking efficiency and reducing the weight and power of actuating motor than electro mechanical brake (EMB). This is due to self-reinforcement features of the wedge mechanism. On the other hand, the conventional hydraulic brake system has the passive wear adjustment without any sensors and actuators. This is because of the sealing rubber which is disposed between the hydraulic cylinder and piston, and supply the piston’s same restoring strokes regardless of pad’s wear amounts. This feature leads to the uniform distance between the disc and the pad. In comparison, electronic brake systems such as EMB and EWB don’t have the hydraulic piston and cylinder with the sealing rubber. Therefore the electronic brake systems cannot use the function of this passive wear adjustment. However, if the electronic brake system has gap sensors for detecting distances between the pad and the disc, and actuators for keeping the uniform distances between the pad and the disc, then the brake system can have the function of wear adjustments. One of our research goals is the embodiment of cost-effective and feasible wear adjustment mechanism which is proper to EWB. In this paper, as a chain of EWB’s development, we describe the proposed mechanism for wear adjustment with EWB. Further we describe the feasibility of this mechanism with the simulation study.
Swirl-Based Control Method of Cell Orientation-Impact on Control Performance with Eccentricity
Authors: Zhang Qin , Wang Jian Hua , Huang Wei Jun , Aoyama Hisayuki
Published: August 2014

The adjustment of cell position and orientation is important in cell micromanipulation of bioengineering, which directly affects the efficiency and success ratio of the micromanipulation. Cell orientation can be adjusted by swirl, which comes from a pair of parallel opposite micro-fluids from two tiny tubes, and the cell in swirl center will rotate. Quantitative control of rotation angle and velocity of the cell can be achieved by adjusting the velocity and frequency of micro-fluid. This control method of cell orientation has prospective applications for its non-contact characteristics. However, cell will not be right in the swirl center in practical operations. And if the eccentric cell can rotate steadily, swirl method will be more reliable. So numerical simulation was conducted to study the movement trajectory of cells with eccentricity, and the influences of eccentric directions and eccentric distances were discussed. The simulation results indicate the feasibility of orientation control of cells with eccentricity by swirl.
Wettability of Polymeric Bionic Surface Replicated from Ginkgo Leaves
Authors: Zhao Xiao Li , An Wei Wei , Yan Jiu Chun , Yu Hai Cao , Wang Li Qin
Published: August 2014

Ginkgo is one of the oldest extant seed plants through hundreds of millions of years of evolution. Ginkgo biloba has many unique properties and applications such as drug development and drinking tea. In recent years hydrophobic surfaces with bionic structures have attracted increasing interest for fundamental research and practical applications. As we all know, the Ginkgo leaf has remarkable texturing surface. In this manuscript, wettability of the bionic surface replicated from Ginkgo leaves was explored. The Ginkgo leaves were used as the original mold, from which microstructures were replicated into the surface of polydimethylsiloxane (PDMS). Compared with the topography of Ginkgo leaves, the topographical surface of PDMS was investigated by optical microscopy and scanning electron microscopy. By measuring the contact angle of polymeric bionic surfaces, there is the increase of ~20 degree than flat PDMS surfaces. Mechanical compression was applied on the polymeric bionic surfaces in one dimension, with the real-time measurement of the contact angle. The experimental results reveal that the wetting behavior of the surface can be reversibly tuned by applied mechanical stress, which induces the change in micro-scale topography. This research provides a guide for fabricating and tuning hydrophobic surfaces for various surface engineering applications.
Steel Health Monitoring Using Magnetic Techniques
Authors: Vourna Polykseni , Ktena Aphrodite , Mpalliou A. , Mamalis Athanasios G. , Hristoforou Evangelos
Published: August 2014

In the present work the determination of intrinsic properties in ferromagnetic materials by using magnetic non-destructive techniques is discussed. Barkhausen noise and bulk permeability measurements were used in various steels. The monotonic dependence of the magnetic response on microstructural features was verified.
Reduction of the Contact Corrosion on the Electrical Networks by Applying Bimetallics
Authors: Szalay Andras , Mamalis Athanasios G. , Vortselas Achilleas K. , Zador István , Lukacs Laszlo
Published: August 2014

The contact corrosion phenomena occuring at the electrical networks when two dissimilar metallic parts are connected to each other causes serious technical and economical problems. One possible solution to reduce the contact corrosion is the application of properly prepared bimetallics. The paper introduces the explosive cladding technique which can be successfully applied for manufacturing bimetallics matched to the given electrical circuit furthermore application possibilities of the explosively cladded bimetallics at electrical networks, railway systems and vehicles.
A Family of Ultra-Thin, Octagonal Shaped Microwave Absorbers for EMC Applications
Authors: Kollatou Theofano M. , Assimonis Stylianos D. , Antonopoulos Christos S.
Published: August 2014

The purpose of this paper is to present efficient models of new octagonal split ring resonant (O-SRR) periodic structures that can offer practical applications for electromagnetic compatibility (EMC) engineers in the area of absorbing materials. The model of an ultra-thin, compact O-SRR absorber for operation at microwave frequencies is introduced, exhibiting very high absorptive regions. The idea is extended to multi-band performance, where two different setups are demonstrated and analyzed. The physics behind the absorption mechanism for the multi-band structures is explained through the surface mechanism.
Prediction of the Energy Losses in Soft Magnetic Alloys Based on the Magnetic Objects Theory in the Case of the Uniform Magnetic Flux Penetration
Authors: Paltanea Veronica , Păltânea Veronika , Gavrila Horia
Published: August 2014

We report an investigation and a theoretical assessment of energy loss prediction in crystalline and amorphous soft magnetic materials. There were tested a sample made from non-oriented silicon iron (NO FeSi) M800-65A, industrial type alloy, cut longitudinally to the rolling direction and a toroidal sample of Co67Fe4B14.5Si14.5 amorphous ribbon. The losses behaviour of the crystalline NO FeSi strip was studied as function of frequency in the range of 5 Hz to 200 Hz at a given magnetic polarization (Jp) of 0.5 T and 1 T. In the case of the amorphous Co-based ribbon the losses variation was studied as function of frequency in the range of 5 Hz to 10 kHz at a given magnetic polarization of 20 mT. Using the concept of loss separation for the data analysis, in the approximation of linear magnetization law and low frequency limit, it can be considered in both cases, that the excess losses can be quantitatively assessed within the theoretical framework of the statistical loss model based on magnetic object theory.
Geometry Investigation of L.R.S. Synchronous Machines Using FEM
Authors: Moschoudis Angelos P. , Filippou Miltiades C. , Tsekouras George J. , Kladas Antonios G.
Published: August 2014

In this paper a geometry investigation of low rotational speed synchronous machines using finite element method is presented. The abovementioned investigation is accomplished using a two step design procedure for salient poles synchronous machines, while a respective example which will be shown synoptically is an under scale design of a low rotational salient pole synchronous motor connected to a ships propeller axis directly.Keywords: Geometry investigation, ships electric propulsion, finite element method, synchronous motor.
Dynamic Performance Assessment of Wind Energy Pump Storage Units in Crete's Power System
Authors: Karapidakis Emmanuel , Georgilakis Pavlos , Tsikalakis Antonis G. , Katsigiannis Yiannis A. , Moschakis Marios
Published: August 2014

Large scale integrating of wind power generation into a grid may raise serious stability issues. In this case energy storage systems seem to be suitable for balancing power and energy between the inconstant wind parks generation and the grid. In this paper, the impact of high wind power penetration on the dynamic performance and stability of power systems is investigated. More precisely, the focus of this study is to assess the operation of pump storage systems in the autonomous power system of a large island such as Crete. Results of this study show that it is possible to achieve a large wind power penetration without significant dynamic security problems, if wind energy pump storage units are in operation.
Design Considerations for an In-Wheel PM Motor with Fractional Slot Concentrated Windings for Light Electric Vehicle Applications
Authors: Krasopoulos Christos , Beniakar Minos E. , Kakosimos Panagiotis E. , Patsios Charalambos , Kladas Antonios
Published: August 2014

Design optimization of traction motors for light electric vehicles requires a comparative analysis in order to account for both performance and efficiency, while considering overall cost, size limitations and manufacturing complexity. This paper presents a comparative study on different surface mounted permanent magnet (SMPM) in-wheel motor configurations, facilitating fractional slot concentrated windings (FSCW). On a first step, different pole/ slot combinations were investigated and evaluated in terms of performance primarily. On a second step, different stator geometries were analyzed, considering both double and single layer windings and both equal and unequal stator teeth. Two different operating conditions were taken into account, i.e. nominal load and overload. The most advantageous was selected, by means of efficiency, clean interface and overall weight, using an extensive sensitivity analysis. On a third step, the final geometry was optimized, via fine-tuning of key design variables, accounting for maximum efficiency and minimum machine weight.
Evolutionary Optimization of a Fractional Slot Interior Permanent Magnet Motor for a Small Electric Bus
Authors: Beniakar Minos E. , Sarigiannidis Athanasios G. , Kakosimos Panagiotis E. , Kladas Antonios
Published: August 2014

Fractional Slot Concentrated Winding (FSCW) Interior Permanent Magnet (IPM) motors constitute a favorable choice for electric vehicle applications due to their inherent advantages of high efficiency and performance, field weakening capability and permanent magnet effective shielding from eddy currents. In this paper, an IPM motor with buried sinusoidal magnets for a small electric bus is optimized in terms of both efficiency and performance. The overall magnet volume and the corresponding iron bridge width are maintained within specified borders, thus enabling adequate field weakening and permanent magnet shielding margins. In the optimization process a single-objective Differential Evolution (DE) algorithm is utilized, showing great convergence characteristics.
Hadfield Steel Hardening by Explosion
Authors: Kovács Tünde Anna , Völgyi Bálint , Sikari-Nágl István
Published: August 2014

It ́s known that the hardness of the metals changes during the cold working. In this paper we analyzed the Hadfield steel hardness in effect of the explosive treatment. We wanted to find a relationship between the detonation velocity and the hardening in case of two different explosives. Also we wanted to find a relationship between the available hardness and the direct and indirect explosive hardening technology parameters. The explosion technology can be useful in case of optimal explosion parameters. The calculation of these parameters need a many experiments. By this work we want give assistance by our empirical results to find optimal hardening parameters.
An evaluation of ozone dry deposition simulations in East Asia
Authors: Park R. J. , Hong S. K. , Kwon H.-A. , Kim S. , Guenther A. , Woo J.-H. , Loughner C. P.
Published: August 2014

Abstract. We use a 3-D regional atmospheric chemistry transport model (WRF-Chem) to examine ozone dry deposition in East Asia, which is an important but uncertain research area because of insufficient observation and numerical studies focusing on East Asia. Here we compare two widely used dry deposition parameterization schemes, the Wesely and M3DRY schemes, which are used in the WRF-Chem and Community Multiscale Air Quality (CMAQ) models, respectively. Simulated ozone dry deposition velocities with the two schemes under identical meteorological conditions show considerable differences (a factor of 2) owing to surface resistance parameterization discrepancies. Resulting ozone concentrations differ by up to 10 ppbv for a monthly mean in May when the peak ozone typically occurs in East Asia. An evaluation of the simulated dry deposition velocities shows that the Wesely scheme calculates values with more pronounced diurnal variation than the M3DRY and results in a good agreement with the observations. However, we find significant changes in simulated ozone concentrations using the Wesely scheme but with different surface type data sets, indicating the high sensitivity of ozone deposition calculations to the input data. The need is high for observations to constrain the dry deposition parameterization and its input data to improve the use of air quality models for East Asia.
Aerosol composition and sources during the Chinese Spring Festival: fireworks, secondary aerosol, and holiday effects
Authors: Jiang Q. , Sun Y. L. , Wang Z. , Yin Y.
Published: August 2014

Abstract. Aerosol particles were characterized by an Aerodyne Aerosol Chemical Speciation Monitor (ACSM) along with various collocated instruments in Beijing, China to investigate the aerosol composition and sources during the Chinese Spring Festival, 2013. Three fireworks (FW) events exerting significant and short-term impacts on fine particles (PM2.5) were observed on the days of Lunar New Year, Lunar Fifth Day, and Lantern Festival. The FW showed major impacts on non-refractory potassium, chloride, sulfate, and organics in PM1, of which the FW organics appeared to be mainly secondary with its mass spectrum resembling to that of secondary organic aerosol (SOA). Pollution events (PEs) and clean periods (CPs) alternated routinely throughout the study. Secondary particulate matter (SPM = SOA + sulfate + nitrate + ammonium) dominated PM1 accounting for 63–82% during the nine PEs observed. The elevated contributions of secondary species during PEs resulted in a higher mass extinction efficiency of PM1 (6.4 m2 g−1) than that during CPs (4.4 m2 g−1). The Chinese Spring Festival also provides a unique opportunity to study the impacts of reduced anthropogenic emissions on aerosol chemistry in the city. The primary species showed ubiquitous reductions during the holiday period with the largest reduction for cooking OA (69%), nitrogen monoxide (54%), and coal combustion OA (28%). The secondary sulfate, however, remained minor change, and the SOA and the total PM2.5 even slightly increased. These results have significant implications that controlling local primary source emissions, e.g., cooking and traffic activities, might have limited effects on improving air quality during PEs when SPM that is formed over regional scales dominates aerosol particle composition.
A new model for the global biogeochemical cycle of carbonyl sulfide – Part 1: Assessment of direct marine emissions with an oceanic general circulation and biogeochemistry model
Authors: Launois T. , Belviso S. , Bopp L. , Fichot C. G. , Peylin P.
Published: August 2014

Abstract. The global budget of tropospheric carbonyl sulfide (OCS) is believed to be at equilibrium because background air concentrations have remained roughly stable over at least the last decade. Since the uptakes of OCS by leaves (associated to photosynthesis) and soils have been revised significantly upwards recently, an equilibrated budget can only be obtained with a compensatory source of OCS. It has been assumed that the missing source of OCS comes from the low latitude ocean, following the incident solar flux. The present work uses parameterizations of major production and removal processes of organic compounds in the NEMO-PISCES Ocean General Circulation and Biogeochemistry Model to assess the marine source of OCS. In addition, the OCS photo-production rates computed with the NEMO-PISCES model were evaluated independently using UV absorption coefficient of chromophoric dissolved organic matter (derived from satellite ocean color) and apparent quantum yields available in the literature. Our simulations show global direct marine emissions of COS in the range of 573–3997 Gg S yr−1, depending mostly on the quantification of the absorption rate of chromophoric dissolved organic matter. The high estimates on that range are unlikely, as they correspond to a formulation that most likely overestimate photo-production process. Low and medium (813 Gg S yr−1) estimates derived from the NEMO-PISCES model are however consistent spatially and temporally with the suggested missing source of Berry et al. (2013), allowing thus to close the global budget of OCS given the recent estimates of leaf and soil OCS uptakes.
Analysis of internal gravity waves with GPS RO density profiles
Authors: Šácha P. , Foelsche U. , Pišoft P.
Published: August 2014

Abstract. GPS (Global Positioning System) radio occultation (RO) data proved to be a great tool for atmospheric monitoring and studies. In the recent decade, they were frequently used for analyses of the internal gravity waves in the upper troposphere lower stratosphere region. Atmospheric density is the first quantity of state gained in the retrieval process and is not burdened by any additional assumptions. However, there are no studies elaborating in details the utilization of GPS RO density profiles for gravity waves analyses. In the presented paper, we introduce a method for the density background separation and a methodology for internal gravity waves analysis using the density profiles. Various background choices are discussed and the correspondence between analytical forms of the density and temperature background profiles is examined. In the stratosphere, the comparison between the power spectrum of normalized density and normalized dry temperature fluctuations confirms the suitability of the density profiles utilization. In the height range of 8–40 km, results of the continuous wavelet transform are presented and discussed. Finally, the limits of our approach are discussed and the advantages of the density usage are listed.
Molecular insights into the microbial formation of marine dissolved organic matter: recalcitrant or labile?
Authors: Koch B. P. , Kattner G. , Witt M. , Passow U.
Published: August 2014

Abstract. The degradation of marine dissolved organic matter (DOM) is an important control variable in the global carbon cycle. For our understanding of the kinetics of organic matter cycling in the ocean, it is crucial to achieve a mechanistic and molecular understanding of its transformation processes. A long-term microbial experiment was performed to follow the production of non-labile DOM by marine bacteria. Two different glucose concentrations and dissolved algal exudates were used as substrates. We monitored the bacterial abundance, concentrations of dissolved and particulate organic carbon (DOC, POC), nutrients, amino acids and transparent exopolymer particles (TEP) for 2 years. The molecular characterization of extracted DOM was performed by ultrahigh resolution Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) after 70 days and after ∼2 years of incubation. Although glucose quickly degraded, a non-labile DOC background (5–9% of the initial DOC) was generated in the glucose incubations. Only 20% of the organic carbon from the algal exudate degraded within the 2 years of incubation. The degradation rates for the non-labile DOC background in the different treatments varied between 1 and 11 μmol DOC L−1 year−1. Transparent exopolymer particles, which are released by microorganisms, were produced during glucose degradation but decreased back to half of the maximum concentration within less than 3 weeks (degradation rate: 25 μg xanthan gum equivalents L−1 d−1) and were below detection in all treatments after 2 years. Additional glucose was added after 2 years to test whether labile substrate can promote the degradation of background DOC (co-metabolism; priming effect). A priming effect was not observed but the glucose addition led to a slight increase of background DOC. The molecular analysis demonstrated that DOM generated during glucose degradation differed appreciably from DOM transformed during the degradation of the algal exudates. Our results led to several conclusions: (i) based on our experimental setup, higher substrate concentration resulted in a higher concentration of non-labile DOC; (ii) TEP, generated by bacteria, degrade rapidly, thus limiting their potential contribution to carbon sequestration; (iii) the molecular signatures of DOM derived from algal exudates and glucose after 70 days of incubation differed strongly from refractory DOM. After 2 years, however, the molecular patterns of DOM in glucose incubations were more similar to deep ocean DOM whereas the degraded exudate was still different.
Physical and biogeochemical controls on light attenuation in a eutrophic, back-barrier estuary
Authors: Ganju N. K. , Miselis J. L. , Aretxabaleta A. L.
Published: August 2014

Abstract. Light attenuation is a critical parameter governing the ecological function of shallow estuaries. In these systems primary production is often dominated by benthic macroalgae and seagrass; thus light penetration to the bed is of primary importance. We quantified light attenuation in three seagrass meadows in Barnegat Bay, New Jersey, a shallow eutrophic back-barrier estuary; two of the sites were located within designated Ecologically Sensitive Areas (ESAs). We sequentially deployed instrumentation measuring photosynthetically active radiation, chlorophyll a (chl a) fluorescence, dissolved organic matter fluorescence (fDOM; a proxy for colored DOM absorbance), turbidity, pressure, and water velocity at 10 min intervals over three week periods at each site. At the southernmost site, where sediment availability was highest, light attenuation was highest and dominated by turbidity and to a lesser extent chl a and CDOM. At the central site, chl a dominated followed by turbidity and CDOM, and at the northernmost site turbidity and CDOM contributed equally to light attenuation. At a given site, the temporal variability of light attenuation exceeded the difference in median light attenuation at the three sites, indicating the need for continuous high-temporal resolution measurements. Vessel wakes, anecdotally implicated in increasing sediment resuspension, did not contribute to local resuspension within the seagrass beds, though frequent vessel wakes were observed in the channels. With regards to light attenuation and water clarity, physical and biogeochemical variables appear to outweigh any regulation of boat traffic within the ESAs.