bluuebunny/crossref_metadata_2025 huggingface dataset:
Optimal Phasor Measurement Unit Placement for Monitoring of PEA Bowin Power
Authors: Khunikakorn Korn , Dechanupaprittha Sanchai
Published: August 2015

This paper presents an optimal method of Phasor Measurement Unit (PMU) placement in Bowin area distribution grid of the Provincial Electricity Authority (PEA) using the Improved Greedy Method (IGM) in order to achieve a minimum number of PMUs for complete observability of all bus voltages. The proposed method introduces the criteria of bus selection for PMU placement, regarding a number of branches connected to the selected bus as well as the length of those branches. Subsequently, the mismatches of the observed voltages resulted from the proposed method are compared with those resulted from the Depth First Search (DFS) using the Power System Analysis Toolbox (PSAT) and the original Greedy method (GDY) to reveal the effectiveness of the proposed placement methods. For the DFS and GDY methods, a bus with the highest number of connected branches is initially selected as the first PMU bus. However, if there is more than one bus, the first PMU bus will be randomly selected from those qualified. On the other hand, the PMU bus firstly selected by the IGM must have the highest number of connected branches as well as the minimum total distance or total impedance of all observable buses. The findings resulted from the IGM are the optimal PMU placement with the total distance of the connected branches less than the other methods, especially for, large-scale networks. According to the comparison results among the DFS, GDY and IGM, the mean absolute error (MAE) of the angle and the magnitude voltage of all buses resulted from the IGM is the lowest for a wide range of load conditions, while the MAE resulted from the DFS is the highest.
Potential Evaluation of Hybrid Wind-Diesel System Island Area in Thailand
Authors: Daunghom Kitsanapol , Premrudeepreechacharn Suttichai
Published: August 2015

Some communities in Thailand located on Island with high wind velocities but an unreliable utility supply, will typically install diesel powered generators and wind generators to form a microgrid. Microgrid projects have been developed in many parts of the world, and commercial solutions have started to appear. Such systems face specific design issues, especially when the wind penetration is high enough to affect the operation of the diesel plant. The dynamic behavior of a medium penetration hybrid microgrid is investigated. It consists of a diesel generator set, a wind power generator and several loads. The diesel engine drives a 3x2,000 kW synchronous generator with excitation control. The wind turbine drives a 6x800 kW (full power converter) synchronous generator. The total load of the microgrid is about 4 MW which varies during the day. The excitation controller and speed controller for the diesel’s synchronous generator are designed, as well as the power control of the wind turbine. The system is modeled and simulated using software DIgSILENT PowerFactory. The study evaluates how the power generation is shared between the diesel generator set and the wind generator, the voltage regulation during load connections, and discusses the need of battery energy storage, the system ride-through-fault capability and frequency control. The results of several case studies are presented. The results have shown that the systems are stable under various ratio of PWIND / PLOAD from 10% to 100%, except ratio of PWIND / PLOAD from 110%.
A Low Frequency Wireless Power Transfer Using Parallel Resonance under Impedance Matching
Authors: Rittiplang Artit , Pijitrojana Wanchai
Published: August 2015

Nowadays, there are more studies about the wireless power transfer (WPT) for mobile charging, electrical vehicles, implantable biomedical devices, and other applications. They (series resonance) commonly operate at high the self-resonant frequency (f0, several hundred kHz - several MHz ranges) based on magnetic coupling under impedance matching (IM). Operating at high f0 to increase the transfer distance, but high f0 (several MHz ranges) causes other parasitic losses of devices and the effectiveness to humans. In this paper, we propose a new method to design WPT using the parallel resonance under IM at low f0. The two coils are 10-turns with the radius of 6.2 cm. The efficiency (35.77 %) of the system under IM is achieved at the transfer distance of 10 cm and f0=20.388 kHz (low frequency), and the transfer distance can be increased by reducing f0.
Comparative Results of Phenology Obtained from Satellite and Ground Observation Images on Paddy Field
Authors: Soontranon Narut , Lawawirojwong Siam , Tangpattanakul Panwadee , Srestasathiern Panu , Rakwatin Preesan
Published: August 2015

Rice is the most significant economic crops in Thailand, which is required to monitor and estimate cultivated area in a wide region. Satellite images are often used to analyze for classifying the paddy area. To validate the results, it is necessary to have ground collection data. For the ground data, instead of field staffs, an equipment called Field Server (FS) has been installed and used to obtain daily images on the paddy field. In this paper, the comparative results of satellite and FS images are experimented in order to understand the correlation between two platforms. Based on the vegetation indices, satellite and FS images are computed for two phenological curves in an observation period. Two curves are compared by using a simple linear regression method (R squared), which can be described the correlation between each other. The phenological curve obtained from FS images is used as a reference. To determine the crop cycle on the satellite images (MODIS), we found that NDVI is more efficient than Excessive Green (ExG) index.
Multi-Window and Line Scan Histogram Features for Bilateral Filtering
Authors: Ongkittikul Surachai , Kesjindatanawaj Wachirapong , Srisuk Sanun
Published: August 2015

Bilateral filtering is the crucial process to enhance the image. This paper aims to improve the bilateral filtering base on the multi-window and line scan histogram scheme. The multi-windows histogram has been introduced to solve the problem when apply to large image by using a number of the window histogram with different weight to estimate the domain filtering function. Anyway, the complexity of this algorithm is increase by multiply of the number ofmwindows histogram that use for estimating the domain filtering. To improve this, our algorithm that based on the multi-windows histogram is proposed which can reduce the complexity of the filtering from O(mB) to O(m+B). Also, our algorithm uses multi-line scan histogram extraction which adapted from dual line scan histogram extraction to reduce the complexity. The experiments show the new algorithm has slightly increase for filtering when increase the number of the window histogramm.
Speech Emotion Feature Extraction Using FFT Spectrum Analysis
Authors: Thiangtham Chaidiaw , Srinonchat Jakkree
Published: August 2015

Speech Emotion Recognition has widely researched and applied to some appllication such as for communication with robot, E-learning system and emergency call etc.Speech emotion feature extraction is an importance key to achieve the speech emotion recognition which can be classify for personal identity. Speech emotion features are extracted into several coefficients such as Linear Predictive Coefficients (LPCs), Linear Spectral Frequency (LSF), Zero-Crossing (ZC), Mel-Frequency Cepstrum Coefficients (MFCC) [1-6] etc. There are some of research works which have been done in the speech emotion recgnition. A study of zero-crossing with peak-amplitudes in speech emotion classification is introduced in [4]. The results shown that it provides the the technique to extract the emotion feature in time-domain, which still got the problem in amplitude shifting. The emotion recognition from speech is descrpited in [5]. It used the Gaussian Mixture Model (GMM) for extractor of feature speech. The GMM is provided the good results to reduce the back ground noise, howere it still have to focus on random noise in GMM for recognition model. The speech emotion recognition using hidden markov model and support vector machine is explained in [6]. The results shown the average performance of recognition system according to the features of speech emotion still has got the error information. Thus [1-6] provides the recognition performance which still requiers more focus on speech features.
A Versatile Analytical Expression of Time Domain Response of Arbitrary Order Fractance
Authors: Banchuin Rawid
Published: August 2015

In this research, a versatile analytical expression of time domain response of fractance with arbitrary order has been derived. Responses to various renowned inputs can be analytically determined by using the derived expression as the basis. This expression has been found to be an efficient analytical tool for various fractance involved disciplines such as biomedical electronics, control systems and analog circuits etc.
Dental Guidelines with Decision Support System for Hypertension and Stroke Patients
Authors: Teerakuldej Tidatip , Soontornpipit Pichitpong
Published: August 2015

The research aims to design and develop the clinical decision support system (CDSS) for supporting clinical practice guideline (CPG) for the dental treatment. The system is created for patients who have hypertension and stroke diseases as they are the third and fourth causes of death in Thailand. Based on patient information retrieved from database in the hospital information system, the system generates the decision support flow using if-then rule base to provide dental precaution of individual patient along with clinical practice guidelines. The system presents stage of hypertension disease, treatment guidelines of each stage, history of stroke occurrence, medicine prescribing data, antiplatelet drug causes of long time bleeding and beta-blocker anti-hypertension drug causes of postural hypotension.
Appointment Tracking System for Improving Patient Waiting Time
Authors: Wattananupong Adrian , Soontornpipit Pichitpong
Published: August 2015

This research aim to design and develop a system that improve the patient waiting time. Appointment system is designed to be the core system that uses to inform the patient’s appointment information. Patient appointment is informed by email and SMS alert to their cell phone. The system provides the appointment time and average waiting time before their queue. When the patients get their treatment, the system tracks down the timestamp for each process from the start till the end to calculate average waiting time. The time results are used for both other patients to determine their waiting time and for hospital management team to verify the quality system.
Analysis of Electromyography in Dynamic Hand Motions Using L-Kurtosis
Authors: Thongpanja Sirinee , Phinyomark Angkoon , Limsakul Chusak , Phukpattaranont Pornchai
Published: August 2015

A statistical measure is needed to estimate a probability density function (PDF) of EMG signals to choose the suitable feature extraction methods for EMG pattern recognition system. The utility of L-kurtosis was investigated in estimating the PDFs of three different dynamic EMG involving transient and steady-state signals during four hand motions measured from two forearm muscles, and was compared with the kurtosis. The results show that the L-kurtosis can identify the PDF of EMG for all cases. In contrast, the kurtosis is inaccuracy and less robust when measured EMG signals have a higher amplitude and are more non-stationary during a transient period.
Modeling of Gelatin-Based Head Phantom Based on its Electrical Properties for Wideband Microwave Imaging Application
Authors: Md Said Mohd Sollehudin , Seman Norhudah , Sulaiman Noor Redzuan , Abd Rahman Tharek
Published: August 2015

This article presents a human head phantom characterization based on the study of its electrical properties across 1 to 6 GHz. The study focuses on the grey matter, white matter, cerebral spinal fluid (CSF), blood and skin of human head. Through the investigation and study of the human head characteristics, its phantom can be modeled using simple and common materials, which are gelatin, water and sugar. The electrical properties of the chosen mixtures of materials mimicking the electrical properties of human head are measured using special dielectric probe connected to a vector network analyser (VNA). This human head phantom later can be applied in the microwave imaging system for a further study on the health monitoring of human body.
Comparative Study of Printed Dipole Antenna with Step-Shaped Feed Gap for DTV Applications
Authors: Apatsaraphom Benjawan , Thaiwirot Wanwisa , Akkaraekthalin Prayoot
Published: August 2015

This paper presents the comparative study of printed dipole antenna with step-shaped feed gap for DTV applications. By proper adjusting the length of arm strips, the additional resonant mode is excited close to the fundamental resonant mode which can form wide operating band. With the equal length of the strip arms of dipole antennas but different step-shaped feed gap (single, double and triple step-shaped feed gap), the single and double step-shaped feed gap can cover the 470-806 MHz band for DTV reception. The dipole antenna with triple step-shaped feed gap can cover the 470-862 MHz band. The simulated and measured results such as return loss, VSWR, radiation pattern and gain for proposed antenna are investigated.
Indoor Navigation and Tracking Using WLAN-Fingerprinting Technique and K-Inverse Harmonic Means Clustering on Mobile Device
Authors: Sangthong Jirapat , Supanakoon Pichaya , Promwong Sathaporn
Published: August 2015

This work evaluated the indoor navigation with the WLAN-fingerprinting technique and k-inverse harmonic mean clustering. During offline phase, the RSS of references node are grouped by KIHM clustering algorithm. In addition, the flag parameter that means the member of each cluster will be added to database. Then, the KIHM membership values will be used to find the cluster and using fingerprinting technique to estimate the target node positions. The best result derived from the KIHM clustering techniques with 3 clusters. The average distance error is approximate 3.73 meters with the 18.41% no error estimated position.
Growth of Anodized Layer and Cerium Sealing on Al7xxx/SiC Composite
Authors: Munir Badrul , Rizkia Vika , Soedarsono Johny Wahyuadi , Suharno Bambang , Rustandi Andi
Published: August 2015

Anodizing process conducted in Al7xxx/SiC produced non-uniform thickness of porous anodic film with cavities, micro-pores and micro-cracks. Cerium sealing was chosen as a post treatment to remedy the poor anodic film by providing a composite layer in order to further enhance the corrosion resistance in aggressive environment. In this study, anodizing process was conducted in H2SO4 solution at current density values of 15, 20, and 25 mA/cm2 at room temperature, 0°C and-25°C for 30 minutes. Subsequently, electroless sealing was conducted in CeCl3.6H2O + H2O2 solution at room temperature and pH 9 for 30 minutes. Integrated protection composed of anodizing at 0°C and cerium sealing process in Al7xxx/SiC produced cerium rich deposits in the diameter of 64 nm (± 3nm) on the surface of anodic oxide layer. These spherical deposits covered the entire surface of anodic oxide layer in accordance with the morphology of the oxide layer. Otherwise, almost no cerium deposit formed on the surface of the oxide layer by conducted integrated protection at room temperature and-25°C. The integrated process conducted at anodizing temperature of 0°C presented a highest protection degree. The cerium protective layer which leads to the decreasing of corrosion rate and current density up to 99,99% or four orders magnifications than that of bare composite.
Molecular Dynamics Study of H2O Molecular Diffusion Behavior in PAM/PVA Polymer Blends
Authors: Wei Qing Hua , Wang Ya Nen , Yang Ming Ming , Chai Wei Hong , Zhang Ying Feng
Published: August 2015

The theoretical method of molecular dynamics was applied to study H2O molecular diffusion behavior in PAM/PVA Polymer blends, investigated the effects of component ratios, temperatures and water contents on diffusion coefficient. Results show that with the increase of PVA content in blend systems, the H2O molecule diffusion coefficient first increased and then decreased. This indicates there is an optimum component ratio to make the H2O molecule diffusion coefficient maximum. There is a certain influence of temperature on H2O molecular diffusion in PAM/PVA blend system, the higher the temperature, the bigger the H2O molecular diffusion coefficient. When the less H2O molecules contained in system, there is a less impact on the diffusion coefficient. As the number of H2O molecules reaches a certain amount, the effect on the diffusion coefficient is more obvious.
A Study on Epoxidised Natural Rubber and Cis 1,4-Polybutadiene Blend
Authors: Kamal Mazlina Mustapha
Published: August 2015

Much published literature on the way in which phase morphology and filler distribution affect blend properties is contractor or confusing The blending of two or more polymers by physical or chemical means may improve a variety of physical and chemical properties of the constituent polymers. The effect of different modes of filler addition on dispersion and viscosity of Epoxidisd Natural Rubber (ENR) and cis 1,4 –polybutadiene rubber (BR) has been studied. Experiments were carried out to elucidate the relationship and to determine whether the use of special mixing technique and compatabilizers might have a beneficial effect on Epoxidised Natural Rubber: Butadiene Rubber (ENR:BR) blend properties. The findings indicated blending times for combining Silica, BR and ENR was rather difficult even a close viscosity of each rubber was applied. Results indicated a high degree of compatibility with fine structured blends being quickly and easily produced with compound containing compatibilizer than compound with any. Hence, a high viscosity and poor filler dispersion was obtained with all mixing techniques applied except with the one with the coupling agent.
Research in Powdering Effects of Environmentally-Friendly Powder Rubber PSBR1500E
Authors: Liang Tao , Wei Xu Ling , Yan Peng Hua , Gong Guang Bi , Cai Wen Jing , Wang Dong Dong
Published: August 2015

The factors that influence environmentally-friendly powder rubber powdering are introduced. Types and dosage of isolation agent, types and dosage of coagulant, environmental antioxidant, condensation temperature, stirring speed on the effect of powder rubber are examined. Thus a simple method to prepare environmental powder rubber is provided.As a physical variation of traditional bulk rubber, powder rubber can change the situations that high energy consumption and high labor intensity of the former. And it also can make the mixing process become continuous, automated, energy-saving and so on. In recent years, with the progress of rubber processing industry, the demand of powder rubber increases rapidly. And there is a intense requirement of supplying environmentally-friendly powder rubber[1-3]. So it is very important to do this experiment.
Fabrication and Evaluation of Corrosion Behavior of Nickel Alloy Metal Matrix Composite with Influence of Chills
Authors: Purushotham G. , Hemanth Joel
Published: August 2015

Nickel alloys have wide-spread applications in mechanical, tribological and corrosion components such as clutches, cylinder liners, pistons in the automotive industry and marine components in sea water owing to its relative corrosion resistant & good thermal conductivity. The presence of silicon results in reduction of the co-efficient of thermal expansion of nickel & produces an alloy with good casting machining & corrosion characteristics. Further it is reported that addition of silica, improves the mechanical properties which in turn has profound influence on the mechanical properties and corrosion behavior of Nickel-SiO2 alloys. Therefore an investigation in the present research will be made to fabricate and evaluate the microstructure, corrosion of chilled composites consisting of nickel matrix and fused SiO2 particles as the reinforcement (size 40-150 µm) in the matrix. The reinforcement being added ranges from 3 to 12 wt. % in steps of 3%. The resulting composites cast in moulds containing metallic and non metallic chill block (MS, SiC & Cu) were tested for their microstructure and corrosion behaviors. The main objective of the present research is to obtain fine grain Ni/SiO2 chilled sound composite having very good mechanical and corrosion properties.
Synthesis of Biodegradable Polyester by Polycondensation with Tunable Properties
Authors: Yeen Lee Xiau , Wahit Mat Uzir
Published: August 2015

A biodegradable cross-linked polyester, poly (1, 8-octanediol-glycerol-dodecanedioate) (POGDA) was prepared from 1, 8-octanediol (Oct), glycerol (Gly) and dodecanedioic acid (DA) without any catalyst. One of the factors, molar ratio of monomers greatly affects the material properties of POGDA and the effect was evaluated. Result showed that the glycerol acts as cross-link agent. When the molar ratio of glycerol increased, the gel content of POGDA became higher. POGDA has a range of glass transition temperature (Tg) with different monomers’ molar ratio. Exist of melting point (Tm) indicated the crystallline region in the polymer. POGDA with low molar ratio of glycerol has high Tm due to the bigger region of crystal. In vitro degradation was performed to investigate the biodegradation behaviour of POGDA. The polymer with tunable material properties by tailoring monomers’ molar ratio is expected to have broad application in medical fields such as drug delivery systems and tissue engineering.
Predicting Methane Diffusivity in Polymeric Membranes by Molecular Dynamics
Authors: Hadj-Kali M.K. , Bessadok-Jemai A. , Haider S. , Alzeghayer Y.
Published: August 2015

Diffusion coefficients of methane (CH4) have been obtained by Molecular Dynamics (MD) simulations combined with Einstein fluid equation. Three polymers were considered, namely polyethylene, polypropylene and poly (cis-1,4-butadiene). All calculations were performed by means of Polymer Builder and Amorphous Cell modules within Materials Studio (Accelrys). The obtained diffusivity results are within the range of published results for similar small molecules. Molecular dynamics simulations proved to be a useful tool for understanding the detailed descriptions and transport mechanisms occurring within the material.
Effect of Processing Factors on the Bonding Strength of Fibrous Assembles by Dielectric Heating
Authors: Joo Chang Whan , Park Dong Su
Published: August 2015

In the dielectric heating by using microwave, both the interior and exterior of fiber materials can be evenly heated simultaneously. Especially, in case of heating the material of low thermal conduction by normal furnaces, thermal loss is great and it takes long time to finish the required treatment. However, if microwave is applied to fibrous materials, it can be treated rapidly. Also, application of microwave system has the results of remarkably enhancing productivity and improving working environment owing to no air pollution. Thus, in this study, the bonded polypropylene (PP) fibers and PP/PET nonwovens have prepared by dielectric heating with various organic solvents, and their morphological structures and debonding force have investigated with different treatment time.
Lost Circulation Material Characteristics of Apple Skin Powder in Drilling Mud
Authors: Ghazali Nurul Aimi , Yusof M.Y.M. , Azizi A. , Mohd T.A.T. , Alias N. , Sauki Arina , Yahya E.
Published: August 2015

Lost circulation is one of the most troublesome problems encountered in drilling due to uncontrolled flow of drilling mud into the formation that likely to happen due to ineffective filter cake. The smaller particles of drilling mud are able to break through into the larger void spaces in the formation which lead to lost circulation. Hence, fibrous materials in apple skin being identified to be used as lost circulation material (LCM) in drilling mud to prevent loss of circulation. Mud rheology tests and API filter press test are performed on the apple skin in drilling mud to find out the potential of fiber in apple skin to be used as LCM. From the mud rheology test, it was found that the specific gravity does not affected by the increasing concentration of apple skin and only a slight reduction in pH value to the acidic condition of the apple skin. As for API filter press test, the additions of apple skin in mud reduced the mud filtrate and increase the mud cake formation thickness. Apple skin fibers have a potential to be used as LCM in drilling mud due to the ability in reducing the mud filtrate and increasing the mud cake thickness that will prevents mud lost circulation problem to happen.
FCC Gasoline Upgrading over Modified Nanoscale HZSM-5 Catalyst
Authors: Zhao Xiao Bo
Published: August 2015

Nanoscale HZSM-5 zeolite was hydrothermally treated with ammonia water at 773K and then loaded with La2O3, NiO and MoO3. The parent and modified nanoscale HZSM-5 zeolite catalysts were characterized by XRD, NH3-TPD, Py-FTIR and N2 adsorption. The characterization results indicated that the acid strength of the parent nanoscale HZSM-5 was weakened, the L/B acidity increased notably and the metal species were well dispersed on the surface of the supports after the combined-modification measurement. In the presence of hydrogen, the performance of the modified HZSM-5 catalyst for FCC gasoline upgrading was evaluated in a fixed bed reactor. Under the given reaction conditions, the average olefin content in FCC gasoline was decreased from 33.2 vol% to 11.3 vol% within 300 h time on stream; the aromatic and isoparaffin contents in the product were increased from 29.8 vol% and 25.9 vol% to 39.0 vol% and 35.4 vol%, respectively. The modified nanoscale HZSM-5 catalyst reduced sulfur concentration in FCC gasoline by about 90% without gasoline octane number loss.
Thermodynamic Analysis of the Effects of Alloying Elements on the Stacking Fault Energy in Ruthenium-Bearing Nickel Alloys
Authors: Kitashima Tomonori
Published: August 2015

The effects of Al, Co, Re, and Ru on the stacking fault energy in Ni alloys were analyzed using computational thermodynamics. The effects of adding up to 5 at% Re or Ru to a Ni-15at%Co system were found to be weak at 300 °C, 700 °C, and 900 °C. However, Al addition decreased the stacking fault energy in a Ni-15at%Co-Xat%Ru system, where X = 0, 3, 5. In addition, this decrease in the stacking fault energy due to Al addition became more significant as the amount of Ru increased. Furthermore, in Ni–Co–Al–Ru alloys containing 9at%Al, the addition of 5at%Ru decreased the stacking fault energy as much as the addition of 12.5at%Co at 900 °C. The effects of Co and Ru addition on the γ/γ’ microstructure of Ni-based superalloys were also discussed.
Solid State Welding Process for Aerospace Components
Authors: Jung Hyun Ho , Lee Ye Rim , Yoon Jong Hoon , Yoo Joon Tae , Min Kyung Ju , Lee Ho Sung
Published: August 2015

Since solid state welded joint is formed from an intimate contact between two metals at temperatures below the melting point of the base materials, the structural integrity of welding depends on time, temperature, and pressure. This paper provides some of examples of friction stir welding and diffusion welding process for aerospace components. Friction stir welding process of AA2195 was developed in order to study possible application for a large fuel tank. Massive diffusion welding of multiple titanium sheets was performed and successful results were obtained. Diffusion welding of dissimilar metals of copper and stainless steel was necessary to manufacture a scaled combustion chamber. Diffusion welding of copper and steel was performed and it is shown that the optimum condition of diffusion welding is 7MPa at 890°C, for one hour. It is shown that solid state welding processes can be successfully applied to fabricate lightweight aerospace parts.
C80 Early Strength Micro Expansion of Steel Tube Reinforced Concrete Research
Authors: Sun Chang Zheng , Wang Zheng
Published: August 2015

Optimization of mix proportion parameter ，Using ordinary raw materials makes a C80 high performance self-compacting concrete;By joining a homemade perceptual expansion agent, significantly improve the early strength of concrete and effective to solve the high strength of self-compacting concrete caused by gelled material consumption big contraction;Further study on the working performance of high-strength self-compacting concrete, age strength, analysis the influence factors of concrete are discussed.
Numerical Simulation of Spherical Indentation Method to Identify Metal Material Properties
Authors: Chen Rong , Li Xiao Yang , Zhang Lin Lin , Wang Xiang Yu
Published: August 2015

The main objective of this paper is to study the indentation process of the spherical indenter by finite element method (FEM). Elastic-plastic model is established and the effect of metal material properties (plastic modulus, yield strength) on response of load-displacement curve during the loading-unloading process is discussed in detail. FEM results indicate that the maximum indentation depths are smaller with larger plastic modulus. For elastic–perfectly plastic materials, the equivalent plastic strain (EPS) grows with the increase of pressed depth and the plastic impact area is constantly changing. In addition, the generated Max depth decreases with the increase of yield strength under the same load. Besides, friction coefficients have little effect on the indentation process. This research provides a theoretical basis for experiment and engineering.
Mechanical Properties of High-Strength Steel Obtained Using DIC for Specimens with a Hole
Authors: Štamborská Michaela , Kvíčala Miroslav , Losertová Monika
Published: August 2015

This article is aimed at determining the mechanical properties of high-strength steel obtained by digital image correlation for specimens with a hole in different rolling direction. This geometry generates a heterogeneous strain field which was measured during the test using a digital image correlation system. The advantage of using a heterogeneous strain field in the identification procedure is that a complex state of stress-strain can be analyzed at the same time and much more information can be obtained in a single test. On the other hand, the stress field cannot be directly computed from the test and a suitable identification procedure must be developed. Here, the virtual fields method (VFM) adapted for large strains and plasticity was used to identify the hardening behaviour and the anisotropy of the material. The values obtained with the VFM were compared with the results from a standard identification made using uniaxial tensile tests.
Finite Element Modeling of Effect of Adhesive Layer and Carrier Thickness Used for Strain Gauge Mounting
Authors: Vadivuchezhian K. , Subrahmanya K. , Chockappan N.
Published: August 2015

Metal foil strain gauges are most widely used for the stress analysis in engineering structures. Typical strain gauge system includes strain sensitive grid, carrier material, and adhesive layer. Strain measurement from the strain gauge is partially affected by carrier and adhesive materials and their thickness. In the present work, a Finite Element Model is developed in order to study the effect of both adhesive layer and carrier thickness on strain measurements while using strain gauges. To understand the behavior of the adhesive material, mechanical characterization is done on bulk adhesive specimen. Finite Element Analysis (FEA) is carried out with different materials namely epoxy and polyurethane. Initially a single element foil loop is considered for the analysis and further this is extended to metal foil strain gauge with nine end-loops. Finally, the strain variation through thickness of adhesive layer, carrier and strain sensitive grid is obtained from FEA. The results thus obtained are compared with analytical results from Basic Strength of Materials approach.
Properties and Microstructure of an Al-Zn-Mg-Cu Alloy Forging
Authors: Li Xi Wu , Xiong Bai Qing , Zhang Yong An , Li Zhi Hui , Liu Hong Wei , Wang Feng , Huang Shu Hui , Yan Hong Wei
Published: August 2015

In this study, the inhomogeneous properties and microstructure at typical position of an Al-7.5Zn-1.6Mg-1.4Cu-0.11Zr alloy forging in T7452 condition have been investigated using OM, SEM, TEM and EBSD analysis, tensile properties testing, conductivity measurement and fracture toughness testing. The results indicate that wherein the properties near the surface layer and in the core of the alloy forging exhibit a difference of 10% or more. There are obvious differences in grain morphology, quench-introduced precipitation and recrystallization degree in the two positions. Due to the high quenching temperature, there appears a heavy quench-introduced precipitation phenomenon in the core more than surface layer of the alloy forging, which improves the electrical conductivity, but significantly reduces the strength of the final material. And there is a higher proportion of the recrystallization organization in the core of the alloy forging, seriously affecting its elongation and fracture toughness. Microstructure inhomogeneity of the alloy forging determines the uniformity of its properties.
Mechanical and Corrosion Behaviors of the Casting Al-Cu Alloy Modified by Nano-Scale PrxOy and LaxOy
Authors: Zhao Hai Long , Zhang Wen , Zhang Chun Lin , Sun Da Qian , Wang Xu
Published: August 2015

The mechanical properties and corrosion behaviors of the casting Al-Cu alloys were investigated. The proportion of the two modifiers (PrxOy and LaxOy) has effects on the mechanical properties and the electrochemical corrosion behavior of the casting Al-Cu alloy. The ultimate true tensile strength of the Al-Cu alloy modified only by LaxOy is the highest (616.0 MPa). The fracture strain of the Al-Cu alloy modified by PrxOy and LaxOy is the highest (12.3%). The Al-Cu alloy modified by PrxOy has better corrosion resistance than any other Al-Cu alloy. The prominent mechanical properties should be attributed to the finer crystal grains and more homogeneously distributed nano-scale phase precipitates. The existence of continuous and compact protective Al2O3 and RE-O films enhanced the corrosion resistance of the modified Al-Cu alloy during the corrosion process.
Influence of Tempertature on Corrosion Behavior of DH36 Steel in Seawater Full Immersion Zone
Authors: Cheng Peng , Huang Xian Qiu
Published: August 2015

Aimed at the corrosion problem of DH36 steel in the seawater full immersion zone, corrosion environment of full immersion zone has been simulated with artificial seawater in laboratory. The corrosion behaviors of DH36 steel in the full immersion zone were investigated by using full immersion tests. The morphology of corrosion products was observed by SEM. Using linear regression analysis to establish the relationship between temperature and the corrosion of DH36 steel. The results showed that the corrosion of DH36 steel immersed in full immersion zone corroded seriously, and the corrosion rate of DH36 steel increased with temperature increasing.
Electromagnetic Micro-Punching Process of T2 Copper Foil
Authors: Zhao Qing Juan , Xu Jie , Wang Chun Ju , Shan De Bin , Guo Bin
Published: August 2015

Electromagnetic micro-punching is a novel micro-punching process in which metal foil occur plastic deformation until shear fracture under magnetic impact load. In this paper, electromagnetic micro-punching process was investigated on T2 copper foil. Effects of discharge energy, foil thickness and discharging time on micro punching were discussed. The results show that micro holes were successfully pierced with the discharge energy more than 5.0 kJ on copper foil of 20 μm in thickness. Foil thickness is the main factor in electromagnetic micro-punching with the discharging energy of 7.2 kJ. In addition, increasing discharging time can punch micro hole on thicker foil. The micro holes with diameter of 0.4-1.4 mm were successfully punched on 20 μm copper foil in thickness with discharge energy of 7.2 kJ.
Research on the Temperature Changes of 20CrNiMoH Steel during Turning Process
Authors: Lin Zhen Ming , Li Jing , Jin Man , Zhang Heng Hua
Published: August 2015

Material cutting properties can be judged by turning temperature and chip shape. A new method that can measure turning temperature more accurately was discussed in this paper. Compared with the traditional method, results show that turning temperature can be accurately measured through a new method in turning process. Turning temperature become stable and will not jump after 20s later. In addition, the higher the hardness, the higher the energy is needed, leading to the higher turning temperature. The average turning temperature of the quenched specimen, normalized specimen and annealed specimen measured through the new method is 100°C,70°Cand 60°C, respectively. And the chip morphologies of quenched specimen, normalized specimen and annealed specimen are irregular band chips, spiral debris chips and C-shaped chips, respectively.
Effects of Preparation Conditions on Alkali-Activation Reactivity of Chemosynthetic Al2O3-2SiO2 Powders
Authors: Huang Dong , Lu Wan Li , Pang Jin Ying , Mo Guo Wei , Yu Shu Juan , Zheng Guang Jian
Published: August 2015

Pure Al2O3-2SiO2 powders with alkali-activation reactivity were prepared by a sol-gel method. The effects of preparation conditions on alkali-activation reactivity were studied and the optimum preparation conditions were obtained. The results show that calcination temperature is a key factor affecting the alkali-activation reactivity of the powders, while other preparation conditions such as synthetic temperature, the molar ratio of solvents to starting materials and drying time have fewer effects on alkali-activation reactivity than calcination temperature. The structure of the powders was investigated by 27Al magic-angle spinning nuclear magnetic resonance spectra. The data show that the Al2O3-2SiO2 powders with the high alkali-activation reactivity are of high content of 5-coordinated Al and the peaks attributed to 5-coordinated Al are strengthened with the rise of calcination temperature of the powders.
Research on Manufacturing the Metal Foams with Regular Cells by 3D Printing
Authors: Yang Si Yi , Zhao Er Tuan , An Yu Kun
Published: August 2015

In the paper the methods of designing and manufacturing of the metals foam with regular cells are researched. The software models of metals foam are designed by CAD. The models are transmitted into 3D printing machine to manufacture foam framework. The metal foams with regular cells and fixed porosities are manufactured by chemical plating, electric plating and investment cast. According to the applications the structures of metal foams can be designed to control sizes, shapes and distribution of pores, porosities, density and to control the properties of metals foam, which can satisfy various demands of applications. Nickel foam with regular cells is designed and manufactured by this method.
Evaluation of Deep Criogenic Treatment at Microabrasive Wear of Aisi D2 Steel
Authors: Silva Cosme Roberto Moreira , Melo Tiago F.O. , Araújo José A. , Ferreira J.L.A. , Gobbi S.J.
Published: August 2015

Wear resistance of tool steels can be increased with deep cryogenic treatment (DCT) application. Mechanisms related to DCT are still not completely understood. Microabrasive wear resistance of cryogenically treated samples of AISI D2 steel was evaluated in terms of austenitization temperature at heat treatment cycle and quenching steps related to DCT. X-ray difractometry, scanning and optical microscopy and quantitative evaluation of carbides with image analysis were carried out aiming material characterization. For samples subjected to higher austenitization temperatures, the DCT treatment does not increase abrasive wear resistance. For samples treated at lower austenitization temperature, the DCT treatment results on 44% increase at abrasive resistance. This effect is correlated to the increase of the amount of fine carbides distributed at samples matrices cryogenically treated.
Development of a Copper Heat Pipe with Axial Grooves Manufactured Using Wire Electrical Discharge Machining (Wire-EDM)
Authors: Nishida Felipe B. , Marquardt Larissa S. , Borges Valquíria Y.S. , Santos Paulo H.D. , Alves Thiago Antonini
Published: August 2015

In this research, a heat pipe with grooves was experimentally analyzed for the application in thermal management of electronic packaging. The heat pipe was produced by a copper tube with an outer diameter of 9.45 mm, length of 205 mm, and capillary structure composed by axial grooves with average diameter of 220 μm. The grooves were manufactured using wire electrical discharge machining (wire-EDM). The working fluid used was de-ionized water. The condenser was cooled by air forced convection and the evaporator was heated using an electrical resistor. This heat pipe was tested horizontally to increasing heat loads varying from 5 to 15 W. The experimental results showed that the heat pipe worked successfully.
Development of CNC Five-Axis Turning Tool Cutter Grinder
Authors: Wang Xiao Wei , Wang Ze Hua , Zhang Mian Hao
Published: August 2015

The precision of cutter grinding decides the level of cutting machining technology, and the precision of cutter is effectively improved through grinding by CNC technology. This paper first analyzed the key parameters of cutter grinding, and realized the functions of CNC five-axis grinding turning tool through design of the structure of CNC five-axis machine tool and building of the control system, to simplify the structure of machine tool, use open CNC control system, and reduce the cost of whole machine, convenient for promotion and use.
Investigation of the Motion of Materials in Cross Section of a Specific Rotary Cooler
Authors: Chen Zuo Bing , Xie Qiang , Shen Yong Peng , Dong Wen Yue
Published: August 2015

Reduced-iron used rotary spray cooler atomizes cooling water and sprays them directly to the outer wall of the cooler, which is called indirect cooling method for which the motion law of the materials in the cooler will have a great influence on the design and the cooling efficiency of the equipment. Based on the DEM simulation, the motion of materials in the cross section is investigated in two dimensions, and the influences of rotation speed, lifters, particles diameter and drum fill are discussed. The research results will guide the operation in real practice and help to optimize the design and control of the equipment to some extent.
Research on the Multi-Actuator and Sensor Detecting Technology Based on Piezoelectric Composite Materials
Authors: Wang Zi Ping , Li Xing Jia
Published: August 2015

Traditional ultrasonic methods are popular in identifying easily detectable cracks, but are not good enough in minute crack detection. Early damage identification is important in preventing larger crack development and future catastrophes. Highly sensitive and precise actuator/sensor is employed to improve the detection capability of these minute cracks. The Orthotropic Piezoelectric Composite Material (OPCM) has been developed as a functional material that can be conveniently used as a highly sensitive actuator/sensor. Comparing the OPCM with the traditional elements, the former has the ability of exciting and receiving focus power and directional strain waves. They have been used in non-destructive technology in many structural engineering inspections. Using the filtering capabilities of the OPCM sensor and Hilbert-Huang Transform (HHT) method, the experimental results show that by using the multi-actuator and sensor, the simulated cracks inside aluminum plane specimen can be successfully identified.
Signal Detection of Welding Joint Flaw Based on Wavelet-Support Vector Machine
Authors: Yin Xin , Liu Yuan Peng , Feng Xian Zhang
Published: August 2015

The friction welded joints made by GH4169 heat metal alloys are detected by U1traPAC system of the ultrasonic wave explore instrument. Aimed at the blemish signal characteristics, this article introduce Support Vector Machine (SVM) theory, which is based on statistical theory and structural risk minimization principle, to carry out multi-classification study of the detection signal. We decompose de-noising signals with wavelet packet transform, and extract energy eigenvalues according to "energy- defects". In accordance with designed "1-to-v" SVMs scheme, we respectively input normalized eigenvector to the SVM model to obtain the Forecast data. It is verificated that the limited existing data and information is well used by SVM and the signal is accurately been classificated. All of these verify that SVM has a strong generalization ability.
Determination of Trace Copper in Vanadium Alloy by Flame Atomic Absorption Spectrometry
Authors: Yang Qiang , Tang Guang Ping , Tian Lun Fu , Wei Qi Long , Wang Chao
Published: August 2015

The determination method for analyzing trace copper in vanadium alloy by flame atomic absorption spectrometry was investigated in the paper. The sample digestion method, digestion acidity, determination conditions, matrix interferences, method precision, recovery of standard addition were investigated in detail. The method precision in RSD% was 8.6%, and the average recoveries of standard addition were from 93.9% to 95.6%. The experimental results indicated that the proposed method for determination of trace copper in vanadium alloy was simple, fast, accurate, and easy to operate, which was suitable for quality control of vanadium alloy.
Using Simulated Data to Support the Calibration Process of ED-XRF Analysis
Authors: Koncz-Horváth Dániel , Gácsi Zoltán
Published: August 2015

In the general practice of ED-XRF measurements, the values of elemental concentrations are derived from complicated calculation methods. Hereby a simple mathematical formula is suggested, which provides an easy way to prepare standard samples. On the other hand, the simulation of spectral lines may also be a helpful tool for the calibration process. In this study, measured and simulated data were used for the quantitative analysis of ternary Au-Ag-Cu alloys. To determine the calibration points, the peak intensity ratio method was applied and the calibration curves were fitted. This work presents the results of a twofold investigation aimed at: a) finding a suitable computational tool to optimise the parameters of the underlying equations and b) testing the reliability of the simulated data to determine the concentrations of multi-element standard samples. Based on comparisons of calculated concentrations it can be stated that a simple calculation method with simulated data provides an easy tool to define calibration standards. It is also demonstrated that the parameters of the linear plots can be optimised to yield improved results.
Stress Non-Uniformity Simulation Analysis of Prestressed Steel Strands in Curved Duct
Authors: Cheng Hai Qian , Zong Wei , Hu Kai , Tian Wen
Published: August 2015

In view of the phenomenon that the curved duct in anchorage zone of cable-stayed bridges result in non-uniformity of each of steel strand, we analyzed the position change law of the prestressed steel strand in curved duct. Simulating real bridge design, a simple method was proposed to compute non-uniformity level of prestressed steel strand in the process of tensioning. Results showed that the rearrangement caused the additional length difference result in stress non-uniformity of each steel strand. Because each of steel strand cannot participate in force at the same time, the actual elongation value of the tendon is greater than theoretical value.