bluuebunny/crossref_metadata_2025 huggingface dataset:
Frequency Dependent Vibration Attenuation of a Suspended Handle Using Piezostack Actuator
Authors: Ahmad Mazlan Ahmad Zhafran , Mohd Ripin Zaidi
Published: May 2015

This paper investigates the effectiveness of piezostack actuator in attenuating the frequency dependent excited vibration of a suspended handle. A shaker is used to produce a base excitation to the suspended handle and a piezostack actuator is used to generate the vibration cancellation for the handle. The investigation covers vibration operating frequency from 50 to 500 Hz. This study also looked at the initial performance of piezostack actuator for the AVC system. A PID controller is design to generate the counter voltage for the piezostack actuator to attenuate the vibration of the handle. The results show that the highest vibration attenuation of the suspended handle occurred at operating frequency of 450 Hz with 90 % of vibration attenuation and the lowest at 50 Hz with 2.4 % of vibration attenuation.
Simulation Advancement in Automotive Development: A Brief Review
Authors: Katoh Hiroshi
Published: May 2015

The automotive development process is advancing through the utilization of CAD/CAM/CAE. This advancement is being enhanced by proper utilization of CAD/CAM integration, Digital prototyping and Digital mock-up. Until recently, CAD has played the leading role for the digitalization of automotive development. However, recent trend shows that, the leading role is shifted from CAD to analysis simulation. Three-dimensional design, which utilizes digital mock-up, is becoming the main tool for product design. Here, the functional capability and predictive assessment by CAE is the core technology. In addition, this supporting role is helping to realize the concurrent engineering in production engineering field.
Design and Analysis of Linear Quadratic Regulator for a Non-Linear Positioning System
Authors: Teng Fong Tang , Jamaludin Zamberi , Bani Hashim Ahmad Yusairi , Rahman Muhamad Arfauz A.
Published: May 2015

The control of rotary inverted pendulum is a case of classical robust controller design of non-linear system applications. In the control system design, a precise system model is a pre-requisite for an enhanced and optimum control performance. This paper describes the dynamic system model of an inverted pendulum system. The mathematical model was derived, linearized at the upright equilibrium points and validated using non-linear least square frequency domain identification approach based on measured frequency response function of the physical system. Besides that, a linear quadratic regulator (LQR) controller was designed as the balancing controller for the pendulum. An extensive analysis was performed on the effect of the weighting parameter Q on the static time of arm, balance time of pendulum, oscillation, as well as, response of arm and pendulum, in order to determine the optimum state-feedback control vector, K. Furthermore, the optimum control vector was successfully applied and validated on the physical system to stabilize the pendulum in its upright position. In the experimental validation, the LQR controller was able to keep the pendulum in its upright position even in the presence of external disturbance forces.
Development of Passive Quarter Car Suspension Prototype
Authors: Aliza Che Amran , Chin Fen Ying , Md Ghazaly Mariam , Chong Shin Horng , Sakthivelu Vasanthan
Published: May 2015

In this paper, a construction of a prototype to represent passive vehicle suspension system for quarter car model is considered. The prototype is represented by two degree-of freedom quarter-car model which are conventionally used by researchers. This laboratory equipment is developed in order to familiarize students with 2 DoF passive suspension system model. It consists of two masses, two springs and a damper. This equipment is easily dismantled and could be assembled with different spring and damper constants which contribute to different characteristics of the suspension system. A number of experiments have been carried out using the experiment setup in order to identify the suspension system characteristics i.e. experiments with different vehicle body mass, different period for one pulse and different pulse width of input pressure of the road excitation have been conducted. The experiment results are evaluated based on the vehicle body displacement and tire displacement of the prototype. Experiment results show that the pulse width of the input pressure or road profile is directly affected the characteristic of this passive suspension system. Lastly, simulations were done in order to compare the simulation and experimental results.
Numerical Investigation of 3-D Turbulent Flow in Orifice Plate within a Pipe
Authors: Alabas Siba Mohamed Abed , Mahmood Wan Mohd Faizal Wan , Nuawi Mohd Zaki , Rasani Rasidi
Published: May 2015

A numerical study of the turbulent flow in an orifice plate within a pipe is carried out by utilizing the Navier-Stokes (N-S) equations. The governing equations are solved using primitive variables with a finite volume method (FVM) and simulated using the finite volume based commercial CFD code ANSYS. The study investigates the influences of Reynolds numbers (Re = 5000, 10000, and 15000) and aspect ratio (β = 0.2, 0.3, and 0.5), on the flow characteristics, i.e. the velocity profile, the differential pressure, and the vorticity, and on the mechanical properties, i.e. the strain, the stress, and the total deformation of the flow around and beyond the orifice. It is found that as the Reynolds number increases, the flow velocity and the pressure increase. The vorticity images show a slightly different behavior. As the Reynolds number has its own effect on the results, it is also found that the aspect ratio affects the results more significantly. The flow patterns are presented for unsteady flow throughout the orifice plate at different values of the Reynolds number.
The Effect of EDM Die-Sinking Parameters on Machining Characteristics in Aluminum Alloy Machining
Authors: Suraya Laily , Ali Mohd Amran , Hussein Nur Izan Syahriah , Muhamad Mohd Razali , Bukhari Manshoor , Lajis Mohd Amri , Raja Izamshah , Mohd Hadzley , Taufik Taufik
Published: May 2015

The effect of machining parameters on machining characteristics for aluminium alloy LM6 (Al-Sil2) in Electrical Discharge Machining (EDM) die-sinking is studied. The objective of this project is to determine the relationship between the machining parameters including pulse-on time, pulse-off time, peak current and voltage with the machining characterictics such as Material Removal Rate (MRR), Electrode Wear Rate (EWR) and Surface Roughness (Ra). Copper materials having diameter 15mm was chosen as the electrode tool. Design of experimenent using Taguchi technique was employed to design experimental matrix that was used to optimize the MRR, EWR and Ra. The analysis was done by using the Minitab software version 16. It is found that current and pulse off time significantly affect MRR, EWR and Ra while pulse on time and voltage are less significant in their effect on machining responses. Results show that using Taguchi as a design matrix, the best setting of optimum value for machining parameters to find the required machining responses can be obtained.
Analysis of Applying Ultrasonic Frequency on a Desktop FDM Nozzle
Authors: Maidin S. , Abdul Aziz Khairul Fahmi , Muhamad M.K. , Pei E.
Published: May 2015

Fused deposition modeling (FDM) is an additive manufacturing (AM) process that has an economical advantage compared to other AM processes. However, its biggest drawback is that it requires post processing to achieve a good surface finish. Ultrasound has been applied in various conventional machining processes and produces a good surface finish. However, the application of ultrasound to AM has not been sufficiently explored. This research aims to investigate the application of using ultrasound technology for a desktop FDM system. The idea is to transmit high vibration from the ultrasonic transducer to the FDM system's nozzle, and the objective is to examine whether the nozzle is able to withstand the high vibration being transmitted. Computer-aided design (CAD) software used to develop the 3D model of the extrusion nozzle component and a computer-aided engineering (CAE) software was used to perform static and vibration analysis. A frequency range of 20 to 30kHz and 30 to 40kHz was applied to the nozzle and it was found that the nozzle was able to withstand frequencies up to 40 kHz of vibration. In addition, the lowest Factor of Safety (FoS) obtained was 18.8975, concluding that the nozzle of FDM can withstand the high vibration transmitted from the ultrasonic transducer.
Flexural Strength Analysis of Dense and Porous Sintered Clay Using Weibull Probability Distribution
Authors: Abubakar M. , Aliyu A.B. , Ahmad Norhayati
Published: May 2015

This research analyzed the results of flexural strength of dense and porous mullite ceramic prepared from kaolin clay by using two-parameter Weibull probability distribution with different estimates. Chemical and physical characterizations of the clay were conducted using XRF, XRD and FESEM. The samples were tested using three point bending tests. The different estimates used in analyzing the results include mean rank, median rank, modified Kaplan Meier and Kaplan Meier. Among the estimates, Kaplan Meier was found to give the best fit with the highest correlation coefficient (R2) value. The porous ceramic had the higher value of Weibull modulus in comparison to the dense ceramic, while the characteristic strength (scale parameter) of the dense ceramic was higher than that of the porous ceramic. The micrograph of the porous ceramic showed a relatively balanced distribution of rounded pores, which is associated with the higher Weibull modulus in the porous ceramic.
Effect of Sintering Temperature on Aluminium Chip Recycling (Al7075) by Powder Metallurgy Process
Authors: Fuziana Y.F. , Rashid Mohd Warikh Abdul , Lajis M.A. , Azam Mohd Asyadi , Mustaffa Ahmad Hariz
Published: May 2015

Al7075 was recycled using the powder metallurgy technique to determine the effect of particle size distribution on the mechanical and microstructure of materials. Analysis of the microstructure, green density and microhardness was conducted to evaluate the performance of the recycled aluminium. The Al7075 was added with 4% of alumina and Al2O3 (3-4μm). The results showed that the green density of recycled Al7075 was lower than the pure Al7075. The average size distribution of the aluminium powder decreased with the increase in the ball mill time. As the temperature of sintering process increased, the green density decreased. The alloy’s microstructure sintered at 650°C has the lowest density, indicating a larger and more frequent porosity. The hardness of the samples with the addition of alumina was higher than the samples without the alumina. Sintering at 650°C also caused the hardness of the sample to increase in the range of approximately 50-62 Hv.
Non-Covalent Polymeric Wrapping of IGEPAL C0890 for Graphene Nanoplatelets (GNPs-C0890) Filled NR/EPDM Rubber Blend Nanocomposites
Authors: Abd Razak Jeeferie , Ahmad Sahrim Haji , Ratnam Chantara Thevy , Mahamood Mazlin Aida , Lau Kok Tee , Ab Maulod Hairul Effendy , Munawar Rose Farahiyan , Mohamad Noraiham
Published: May 2015

Graphene nanoplatelets (GNPs) surface modification was performed by using a simplified dual-action of ultrasonication and high speed mechanical shearing. This approach induced a non-covalent polymeric wrapping interaction between GNPs surfaces with IGEPAL-C0890 (ethoxylated nonyl phenol with 40 moles ethylene oxide). Various characterization tools like FTIR, Raman spectroscopy, FESEM and TEM were utilized to confirm the success of the surface treatment. The efficacy and suitability of non-covalent treated GNPs-C0890 as nanofiller reinforcement and inorganic compatibilizer in NR/EPDM rubber blends were evaluated. Effects of GNPs-C0890 loading variation to the mechanical tensile properties and fracture morphologies of NR/EPDM nanocomposites rubber blend were studied. It is interesting to note that the GNPs-C0890 was not able to reinforce NR/EPDM blend at a higher loading addition (≥ 3.00 wt.%) due to the agglomeration and crosslinking retardation phenomena by phase separation. However, at a lower loading (≤ 1.00 wt.%), the blend strengthening effects promise the improvement at about 64.55% of tensile strength and 14.20% of elongation percentage as compared than unfilled NR/EPDM blend. Obvious fractured morphological changes due to the absence and presence of GNPs provide hints on the role of GNPs treatment in effecting the NR/EPDM rubber blend mechanical properties.
Effect of Neodymium and Samarium on the Properties of Bismuth Titanate Ceramics
Authors: Azlan Umar Al Amani , Mohd Noor Ahmad Fauzi , Yusuf Yusliza , Omar Nooririnah , Mohamad Noraiham
Published: May 2015

This paper reported the doping effect on BIT by two different rare-earth compounds i.e. Nd and Sm, each at different mole content (0.25, 0.5, 0.75 and 1.0 mol). The so-called single-step combustion synthesis was used to produce the as-combusted powders, whereby the intermediate calcination step was then eliminated. This method was able to sinter the samples at temperature as low as 1000°C for 3 h. The entire ceramics were characterized for phase detection and stability, microstructure and dielectric properties. It was found that the single phase BIT was successfully formed with Nd and Sm doping. However, little content of pyrochlore phase was detected in the sample with Sm doping particularly at high mole content. (0.5 to 1.0 mol). Besides, a remarkable decrease in the grain size with better microstructure was observed particularly at high mole content (1.0). The improvement in microstructure led to the increase in dielectric constant with low dielectric loss.
Control of Cobalt Catalyst Thin Film Thickness by Varying Spin Speed in Spin Coating towards Carbon Nanotube Growth
Authors: Zulkapli Nor Najihah , Abd Manaf Mohd Edeerozey , Ab Maulod Hairul Effendy , Abdul Manaf Nor Syafira , Raja Seman Raja Noor Amalina , Bistamam Mohd Shahril Amin , Talib Elyas , Azam Mohd Asyadi
Published: May 2015

Cobalt (Co) catalyst thin film is an active metal catalyst that can be very helpful to grow carbon nanotubes (CNTs). The catalyst thin films were prepared on silicon wafers by spin coating the solution of cobalt acetate tetrahydrate and ethanol. The effects of different spin speed parameter during the spin coating process were investigated. The findings showed that the optimum thickness of the Co catalyst thin films, i.e., 12.1 nm, was obtained at the highest spin speed of 8000 rpm. The uniformity of the thin films was also found to increase with increasing spin speed. The study also demonstrated that single-walled carbon nanotubes could be grown from Co catalyst particles after the catalytic chemical vapor deposition of ethanol. The particle and thickness analysis, as performed by means of FESEM while the existence of CNTs, was performed by Raman spectroscopy.
Fabrication of Activated Carbon Filled Epoxidized Natural Rubber Composite Using Solvent Casting Method
Authors: Azam Mohd Asyadi , Hassan Aisyah , Mohamad Noraiham , Talib Elyas , Abdul Manaf Nor Syafira , Najihah Nor , Raja Seman Raja Noor Amalina , Bistamam Mohd Shahril Amin
Published: May 2015

Despite the rapid increase in the utilization of reinforced nanomaterials composites, micromaterials may also have the potential to be utilized as filler in polymer composites. In this study, the activated carbon (AC) filled epoxidized natural rubber (ENR) composite was fabricated using the solvent casting method. AC was used as the filler at different filler addition in range from 0 to 7 parts per hundred rubbers (phr). The intention was to investigate the effect of AC filled ENR on mechanical properties and interaction between AC and ENR matrix. Overall, the result shows high improvement in mechanical properties. At 7 phr, the tensile strength was 7.0 MPa compared to 2.6 MPa for 0 phr, which indicates the increase by almost 2 times. The elongation also increases for all phr, which indicates the good filler effect.
Cure Characteristics of Natural Rubber/EPDM Blends for the Effect of MAH Grafted EPM and Compounding Parameters via Response Surface Methodology
Authors: Mohamad Noraiham , Mahamood Mazlin Aida , Abd Razak Jeeferie , Munawar Rose Farahiyan , Zainal Abidin Muhammad Zaimi , Azam Mohd Asyadi , Kasim Mohd Shahir , Othman Mohd Shahrizan , Shueb Mohammed Iqbal
Published: May 2015

Natural Rubber/EPDM blends were successfully prepared by direct melt compounding method using an internal mixer. The significance of MAH grafted EPM (MAH-g-EPM) and compounding parameters were studied via the response surface methodology (RSM) using the two-level full factorial design. The MAH-g-EPM loading, mixing temperature, rotor speed and mixing time were selected as four independent variables. Cure characteristics of scorch time, cure time and maximum torque were selected as the responses. The statistical significance of all variables and their interactions during compounding were analysed using ANOVA. The degree of agreement between experimental results with those predicted by the statistical model was confirmed using constant of determination, R2 with values approaching ~0.99. It was observed in the results, that the incorporation of high loading (10 phr) of MAH-g-EPM has predominantly enhanced the scorch safety time of NR/EPDM blends, as well as increased the modulus of NR/EPDM blends to some extent compared to low loading (5 phr and 7.5 phr). These finding were further supported by the Differential Scanning Calorimetry (DSC) analysis.
Design Simulation on Fatigue Life of Fiber Reinforced Polymer Composites
Authors: Rosfadzlin Hanna Z.A. , Taufik Taufik , Sivaraos Sivaraos , Mohd Ghazali S. , Rosidah J. , Mohd Amran M.A.
Published: May 2015

Fibre reinforced polymer composites have been widely used in automotive industries due to its high tensile strength, lightweight and potential resistance towards environmental conditions. This paper presents a study on the fatigue life prediction of fibre-reinforced polymer (FRP) and the application of FRP composite in manufacturing engineering industries. Four designs of I-beam with different thickness and fillet were studied. The analyses of fatigue life of the designs were done using ANSYS software. Results from the analysis showed that the combination of glass/polyester and the design of I-beam with a fillet of 10mm and thickness of 20mm was the best combination in terms of its good fatigue life, factor of safety and stronger top surface.
Synthesis and Characteristics of Mesoporous SBA-15 Influence by HMTA as an Internal pH Modifier
Authors: Mohd Husin Mohd Haizal , Nordin Mohd Ridzuan , Mohamad Imran Syakir , Li Jin Li
Published: May 2015

SBA-15 mesoporous silica was directly synthesised under difference acidic conditions by a “pH modification method” using hexamethylenetetramine (HMTA) as an internal pH-modifier. The synthesised material has been characterised by XRD, Nitrogen adsorption–desorption, and TEM. The characterisation results showed that mesoporous silica lead to high-ordered hexagonal mesoporous morphology by TEM at high acidity compared to low acidity condition. In addition, the physical properties of SBA-15 showed a decrease of surface area and pore size due to the increase in the pH. Use of HMTA as pH modifier is suitable, due to pH value increases occurred in the hydrothermal processes only. This is because during the hydrothermal process at a temperature of 100°C, HMTA decomposes to NH3 which in turn increase of the pH value in the silica gel. It can be concluded that the formation of mesoporous silica SBA-15 to some extent been influenced by the pH value. This can be seen from the results of the study show that mesoporous silica type SBA-15 lead to well-ordered hexagonal mesoporous at high acidity and poor order hexagonal pore structure was formed in low acidity condition.
Way Forward to Halt Pressure Loss in Automotive Tyres
Authors: Raguvaran M.J. , Sivaraos Sivaraos , Amran Mohd , Anand T. Joseph Sahaya , Qumrul Qumrul , Izamshah Raja , Dahlan A.S.
Published: May 2015

Tyre is one of the most crucial components in a vehicle structure not only to have the vehicle running smoothly on the road, but also to provide physical and acoustic comfort for the passengers. But, since the day the inflatable tyres were invented, sudden loss of air in a tyre acts as a major problem associated with tyres; and are still being treated to date by professional researchers and giant tyre manufacturers. The phenomena where tyre experiences natural pressure loss over the time is called air permeation which causes tyre to deflate on its own. Besides reviewing the primary theories and findings that contribute to natural air permeation that literally causes the pressure drop of an automotive tyre, this paper also reveals the experimentally validated results of the significant factor which contributes to air permeation of an automotive tyre. Additionally, a relevant nanobased solution to reduce the air permeation rate to stop the tyre deflation is also highlighted to establish the way forward total solution suiting wide range of tyres used on domestic cars.
Correlation between Process Parameters with Flexural Properties of Hybrid Glass/Jute Fibre Reinforced Epoxy Composite Fabricated via Vacuum Infusion Technique
Authors: Mohamad Noraiham , Hassan Mohd Fadli , Chang Siang Yee , Ahsan Qumrul , Yaakob Yuhazri , Ab Maulod Hairul Effendy
Published: May 2015

Flexural properties of hybrid glass/jute fibre reinforced epoxy composites were optimised by response surface methodology. The processing parameters of vacuum infusion technique such as supply pressure, soaking time and use of flow media were investigated. The flexural properties of the resulting composites were evaluated using three-point bending test in accordance with the ASTM D790-03 standard. The flexural strength of ~195 MPa and elastic modulus of ~13412 MPa were achieved at optimum parameter of 100 kPa pressure, 120 minutes soaking time with the utilization of flow media during vacuum infusion process.
Lean Principles Approach in Solving Poor Risk Management: A Short Review
Authors: Puvanasvaran A.P. , Subramaniam R. Parameshwaran Rasiah , Mohd Syaiful Rizal
Published: May 2015

Managing risk at the beginning stage of product development is considered to be the answer in securing a business future and success for any organization in the long run. Lean principles have an important role in ensuring the success of implementing risk management to identify and eliminate product risk at the early stages. This paper aims to review the lean principles approach in solving poor risk management. Although lean principles usually use tools, this study describes the further use of integrating lean principle to identify the important elements and advantages for risk management in the new product development (NPD) stage. This study also proposes the conceptual framework of a project management development system, which can help to ensure that organizations always stay competitive in the market and improve the skills of project managers for proper development execution.
The Implementation of Product Architecture in Developing Conceptual Design for Passive Grease Trap
Authors: Juffrizal K. , Nidzamuddin M.Y. , Tan Chee Fai , Abdollah M.F.B. , Zulfattah Z.M. , Mohamad Noraiham , Maslan N.M.
Published: May 2015

The procedure, by which the functional and physical elements of a product are arranged, is known as the product architecture. It highlights the interaction between parts of product. It is a phase where the function of a product is assigned to its physical. The role of product architecture in a product development is very vital since a comprehensive choice of the product architecture provides a good idea on how the functions are understood and how a standardization is achieved. In this regard, this paper presents the following: the product schematic, product cluster, product geometry, and fundamental and incidental product elements interactions of a grease trap design.
Cutting Technology Innovation in Production of Porous Cellular Mat
Authors: Mohd Hadzley Abu Bakar , Izamshah R. , Amran Mohd , Farhan W. , Azran M. , Azahar W. , Wijeyesekera Devapriya Chitral
Published: May 2015

Innovative developments of hollow cellular mat for lightweight structure must satisfy sustainability, fit for purpose and optimize design concepts. However, such materials necessitate appropriate cutting technology to allow trimming and shaping operations to be easily carried out on an excessive porous and perhaps non uniformity nature. This paper presents a work that aims at studying the machinability of porous cellular mat using a newly innovative cutting technology. A large structure of vertical bandsaw has been fabricated to cut the product with the size of 1m (width) x 1m (height) x 1m (long). The systems also equipped with a feeding table and strong structure frame to avoid product shifting during the cutting operation. The surface integrity showed minimum deformation with uniformed direction of surface removal marks. The cutting technology developed in this study is suitable for the hollow cellular mat for its simple trimming and shaping process and fine surface profile.
The Concept of Single Use Piston Break Safety Syringe
Authors: Mazlan A.M. , Sapiee M.R. , Yahaya M.S.
Published: May 2015

A syringe is a simple piston pump consisting of a plunger that fits tightly in a tube. The plunger can be pulled and pushed along inside a cylindrical tube (the barrel), allowing the syringe to take in and expel a liquid or gas through an orifice at the open end of the tube. The open end of the syringe may be fitted with a hypodermic needle, a nozzle, or tubing to help direct the flow into and out of the barrel. Syringes are often used to administer injections, apply compounds such as glue or lubricant, and measure liquids. The reuse and abuse of syringe has led to cross-infection of diseases; thus, the need of single use safety syringe arises. Single use safety syringe is able to prevent the abuse of syringe. Many inventions have been produced; the most common are through-push retract breakable safety syringe, rotary plunger retractable safety syringe and release-ring breakable safety syringe. A new type of single use safety syringe Piston Break Safety Syringe is discussed in this paper. The new Piston Break Safety Syringe has similar design with the widely used safety syringe; hence, it makes it easier to be adapted by the users due to its similarity, since no extra training is required. The cost should be equivalently low due to the similarity in size, design and number of components.
Mechanical Properties Comparison of Stainless Steel 304L and Carbon Steel BS1387 Prior to Orbital Welding
Authors: Ayof Mohamad Nizam , Noh Z.M. , Hussein Nur Izan Syahriah
Published: May 2015

Dissimilar metal joint (DMJ) is one of many joining methods for welding processes which is common in the power plant, chemical and petrochemical industries. Stainless steel pipe and carbon steel pipe are the most widely used in this technique. In order to perform DMJ to these metals, it is important to understand the mechanical properties of both base materials. In this study, the characterizations of stainless steel (SS) 304L and carbon steel (CS) BS1387 were made. The SS 304L and CS BS1387 were cut out from pipes according to ASTM E 8M-04, before their tensile and microhardness properties were measured and evaluated. The results show that the SS 304L has better mechanical properties compared to the CS BS1387 pipe in terms of tensile strength and hardness. Due to the higher mechanical properties, SS 304L was selected to conduct higher temperature water, while CS BS1387 was selected to conduct room temperature water.
Dynamic Simulation of a Parallel Topology Robot Operation
Authors: Miclosina Calin Octavian , Cojocaru Vasile , Korka Zoltan Iosif
Published: May 2015

In this paper, the geometrical model of a guiding device mechanism of a parallel topology robot proposed as a flight simulator is presented. For the operation simulation, the input parameters are the relative displacements of driving kinematical joints links versus time. The displacements of 2 characteristic points on the mobile platform are determined, as well as their velocity and acceleration variations. Also, the variations of kinematic and potential energy of human operator geometrical model and the variation of power consumption for different operating conditions are accomplished. For geometrical modeling and dynamic simulation, SolidWorks software is used.
Inverse Kinematics Model of a Bucket Excavator’s Digging Equipment
Authors: Dima Marian , Frâncu Cătălin
Published: May 2015

This paper presents a method to build the inverse kinematics model of a bucket excavator’s digging equipment. The model is determined by using two different methods, the matrix method applied on the decoupled forward kinematics model and respectively the geometric model.
Researches Regarding Pose Accuracy Characteristics at Industrial Robots
Authors: Vacarescu Valeria , Buciuman Cella Flavia
Published: May 2015

Analyzing applications involving industrial robots, these can generally be classified into two categories. In the first category, the robot is used to position an object or a tool in its working space. In the second category, the robot is used for programmed and continuous movement of an object in the working space. These two categories of use of industrial robots determine two families of characteristics considered fundamental for the assessment of performance robots: pose characteristics and tracking path characteristics. The pose characteristics are generally expressed by the pose accuracy and pose repeatability (positioning and orientation). From this category is “distance accuracy”, whose analysis is the subject of this paper. The authors present a method for measuring and evaluating of this characteristic, through 3D triangulation with two digital theodolits. The experimental researches were made for a welding robot type Cloos-Romat. The presented case study validates the results of the experimental research, the method and the used algorithm.
A Literature Survey on Reconfigurable Industrial Robotic Work Cells
Authors: Fulea Mircea , Popescu Sorin , Brad Emilia , Mocan Bogdan , Murar Mircea
Published: May 2015

As the unpredictability of market needs and the mass customization trends increase, employing reconfigurable industrial robotic work cells becomes a viable solution for manufacturers. A reconfigurable manufacturing system is a system designed for a quick change in structure, both in hardware and software, in order to rapidly adjust production capacity and functionalities. However, the approach is quite general; a simple search within scientific literature, patent databases or the world-wide-web returns thousands of results, covering a time period from the 80s to date. Among the results, different approaches on reconfigurable industrial robotic work cell implementations can be easily noticed. This paper surveys the literature in reconfigurable industrial robotic work cells, aiming to identify, besides the most important approaches on this topic, also performance criteria associated to robotic workcell reconfigurability and means of measuring the reconfigurability degree of such cells. The survey also aims to identify command and control architectures used to achieve various levels of reconfigurability. The survey was conducted by using a specific search methodology, which is also presented in the paper.
Quaternion-Based Algorithm for Direct Kinematic Model of a Kawasaki FS10E Articulated Arm Robot
Authors: Popa Stelian , Dorin Alexandru , Nicolescu Florin Adrian , Ivan Andrei Mario
Published: May 2015

This article follows a detailed description of development and validation for the direct kinematic model of six degrees of freedom articulated arm robot - Kawasaki FS10E model. The development of the kinematic model is based on widely used Denavit-Hartenberg notation, but, after the initial parameter identification, the mathematical algorithm itself follows an approach that uses the quaternion number system, taking advantage of their efficiency in describing spatial rotation - providing a convenient mathematical notation for expressing rotations and orientations of objects in three-dimensional space. The proposed algorithm concludes with two quaternion-based relations that express both the position of robot tool center point (TCP) position and end-effector orientation with respect to robot base coordinate system using Denavit-Hartenberg parameters and joint values as input data. Furthermore, the developed direct kinematic model was validated using the programming and offline simulation software Kawasaki PC Roset.
Calculating Angles of Rotation of the Robots Elements for Given Position and Orientation Depending on the Gripping Device
Authors: Popa Constantin , Dinu Ion , Voiculescu Luminiţa , Duţu Mihaela Florentina , Dragomir Maria , Ovanisof Alina
Published: May 2015

This paper deals with the calculation of the angles of rotation of the robots elements. Determination of the position of the gripping device orientation occurs when it touch the working object. The position of working object will determine and rotation of the manipulator elements that must perform database actions.
Winding of Carbon Wire Composite Structures Using Two Cooperative Industrial Robots
Authors: Sbanca Madalin Petru , Mogan Gheorghe Leonte
Published: May 2015

In this paper are presented aspects concerning new method of winding carbon wire to obtain composite structure using two cooperative industrial robots. The goal of this study is to use two robots working together for creating only one part obtaining faster cycle time like manual method. For this are proposed some collaboration methods between robots and different methods of trajectory plan. First proposed obstacle is when the position of the robots between them is unknown. For this is proposed a calibration algorithm for robot positions. The collaboration must be very fast. For this the proposal is to use direct communication between robots using digital inputs and outputs. For trajectory planning is involve the virtual space for designing and testing the trajectory and then transpose the results in real robots controller.
Bending Vibrations of a Viscoelastic Euler-Bernoulli Beam – Two Methods and Comparison
Authors: Craifaleanu Andrei , Orăşanu Nicolaie , Dragomirescu Cristian
Published: May 2015

The study of the bending vibrations of Euler-Bernoulli beams is typically performed based on pure elastic material models, which neglect the damping. However, in practice, due to the internal friction of the material, the vibrations are damped. This phenomenon can be taken into account by using a viscoelastic material model, in which supplementary strains, dependent on the strain rates, are considered. In the paper, free bending vibrations of homogeneous viscoelastic Euler-Bernoulli beams are studied by developing generalized forms of an exact and of an approximate method, respectively, used regularly in the study of pure elastic Euler-Bernoulli beams. The developed methods are applied and compared on a numerical example, highlighting their advantages and limitations.
Energies of Accelerations in Advanced Robotics Dynamics
Authors: Negrean Iuliu , Kacso Kalman , Schonstein Claudiu
Published: May 2015

This paper is devoted to the presentation of new formulations on the higher order motion energies that are used in the advanced dynamic study of robots. Integral part of these mechanical systems are the mechanical robot structures, on which an application will be presented in order to highlight the importance of the higher order motion energies regarding the dynamic behavior. In current dynamic studies, the kinetic energy is used as a central function in Lagrange - Euler equations. This paper extends the study by developing the acceleration energies of first, second and third order and their implementation in differential equations of motion of third and fourth order, which gives the possibility of applying the initial motion conditions in positions, velocities and accelerations of first and second order. This leads to a more precise control on the transitory motion phases of the multibody systems, in which the robot structures are included.
A Method to Fabricate Thin Micro Silicon Cantilever Based on Optical Lithography with AZ 1518
Authors: Tang Chen Zhi
Published: May 2015

AZ 1518 is a standard thin positive photoresist in AZ1500series which has been widely used in photolithography process, beside this, as a perfect semiconductor material, micro sized silicon cantilevers have been widely used in micro electromechanical systems (MEMS). In This paper, we have presented the process of fabricate micro silicon cantilever, including the selection of the photoresist, developer and substrate, optical lithography method and PLD method. After these, AFM is used to study the cantilever pattern and the angle of inclined planes. The research results show the exposure time and experimental environment can significantly influent the quality of cantilever pattern.
Study on the Etching Technique of Non-Photosensitive Polyimide
Authors: Lei Rui , Liu Wei Guo , Cai Chang Long , Zhou Shun , Nie Jing , Wang Xuan Yang
Published: May 2015

Polyimide is often used as a sacrificial layer material to make floating structure. Polyimide is also divided into photosensitive and non-photosensitive type; photosensitive polyimide currently has more negative photoresist and poor performance in many ways. Compared with photosensitive polyimide, the non-photosensitive type has low stress, stable performance and other advantages, so non-photosensitive polyimide has been chosen as a sacrificial layer material. To achieve the graphical function and release sacrificial layer, A deeply research was made in this dissertation makes on wet etching and dry etching. By controlling the wet etching process of prebake condition, exposure and developing time, and oxygen dry etching process of etching power, bias voltage and other key process parameters, a good sacrificial layer graph and etching effect have been got. Finally, it can be concluded that when the prebake conditions for 105°C, 8min and times of exposure and developing were 11s and 29s, the non-photosensitive polyimide wet etching effect is the best; when the etching power is 1000w, an oxygen flux rate is 50sccm, the reaction pressure is 30mTorr, the bias voltage is 140v, oxygen dry etching has a good effect.
Strategies for Defect-Free and Deep Wet Etching of Pyrex 7740
Authors: Zhan Zhan , Yu Ling Ke , Zheng Cheng , Cai Jian Fa , Sun Dao Heng , Wang Ling Yun
Published: May 2015

In this paper, two aspects in the wet glass etching, the pre-annealing of the glass and the mask process, are taken into consideration to achieve the deep and defect-free wet etching of Pyrex glass. Compared with the conventional strategies, i.e.,HFsolution component and mask kinds, our experiment results prove the pre-annealing is another key role to obtain theoretical isotropy character in wet etching. Besides, the high temperature pre-annealing dramatically improves the structure profiles and reduces the notching defects. Additionally, a novel multilayer mask process is proposed. With 1.5μmPR/ 100nmAu/ 100 nmAu/ 20 nmCrmask and > 450 °C pre-annealing, > 150 μm deep and non-pin-holes Pyrex glass structures are achieved and the roughness of etched surface is lower than 1 nm.
Research on the Preparation of Nanoporous Copper Using Taguchi Method
Authors: Li Ke Cheng , Liu Xiao Gang , Chen Yong , Chen Ming Xiang
Published: May 2015

In this work, the influences of process parameters including electroplating time, annealing temperature, etchant concentration and dealloying time on the microstructures of nanoporous copper (NPC) were quantitatively evaluated in terms of pore size. Taguchi method was utilized to reduce the number of experiments required for the evaluation. The effect of each parameter variable on the characterization length scale of NPC was quantified and discussed. It was found that the annealing temperature was the most dominant factor influencing the microstructure of NPC and the dealloying time, electroplating time and etchant concentration contributed sequentially weakly to that of NPC.
Effects of NaOH Concentration on Section Structures of Oxide Films Based on TC4 by Anodic Oxidation Process
Authors: Yan Ji Kang , Yang Gang , Shi Zhe , Tang Wan Xia , Wu Yun Feng
Published: May 2015

The section structure and growth mechanism of oxide films on titanium alloys Ti-6Al-4V (TC4) in the oxalate, silicate and phosphate hybrid electrolyte system by anodic oxidation method were investigated. Using TC4 as anodic, stainless steel as cathode, oxide films on the surface of TC4 titanium alloy were prepared by anodic oxidation process. X-ray diffract meter, spiral-micrometer, eddy current thickness meter and scanning electron microscope were used to measure the crystal structure, thickness, microstructure and chemical composition of the film . The experimental results indicate that NaOH concentration has almost no effects on the crystal structure of oxide films which are amorphous state. The oxide films on TC4 grow through three stages. At anodic oxidation primary stage, a thicker TiO2films on TC4 are able to form due to an abundant oxygen atmosphere. At anodic oxidation middle stage, a middle TiO1.5films form due to a not enough oxygen atmosphere. At anodic oxidation latest stage, a thin TiO1.5films form due to a heavily insufficient oxygen atmosphere. With NaOH concentration increasing, the ingrowth velocity (VOA) of the interface between TC4 and oxide film is faster than dissolution rate (VAD) of the surface oxide film resulting in a slight oxide film growth. The thickness of oxide film no longer varies when VOAis equal to VAD.
Q-Factor Improving of Film Bulk Acoustic Wave Resonator for Chip-Scale Atomic Clocks
Authors: Zhang Zhong Shan , Tang Liang , Ji Lei
Published: May 2015

Film bulk acoustic wave resonators (FBARs) with relatively high Q-factor are considered good candidates to be used in the RF module of chip-scale atomic clocks (CSACs). In order to simulate and analyze the resonant properties, the Mason equivalent circuit of the FBAR device is introduced, which consists of five parts including top electrode layer, low temperature silicon oxide layer, piezoelectric layer, bottom electrode layer and a composite support structure layer. With the practical processing conditions considered, the piezoelectric layer with a reasonable thickness of 1.30um is selected to achieve a FBAR device with resonant frequency 4.60GHz and Q-factor 278 by the simulation and analysis. In order to further improve the Q-factor, SiO2 thin films with thicknesses from 0.10um to 0.50um placed between the top electrode and piezoelectric layer are introduced. However, as the SiO2 thin film is introduced, the resonant frequency of the FBAR device will drop. In order to keep the resonant frequency fixed to 4.60GHz, the thickness of the piezoelectric layer is adjusted. Finally, the FBAR device resonating at 4.60GHz with Q-factor 627 is achieved, the thicknesses of the SiO2 film and piezoelectric layer of which are 0.20um and 0.69um respectively. The Q-factor of the FBAR device improves about 350, and the FBAR device is expected to be used in CSACs.
Fluid Dynamic Analysis on Solar Heating Error of Radiosonde MEMS Humidity Measurement
Authors: Mao Xiao Li , Zhang Jia Hong , Li Min , Xiao Shao Rong , Liu Qing Quan
Published: May 2015

The dry bias of MEMS humidity sensor induced by solar radiation heating seriously affects the accuracy of the relative humidity (RH) measurement. To solve this problem, this paper presents a novel numerical analysis method for the error correction of RH based on computational fluid dynamics (CFD). Firstly, considering the solar radiation, the distribution of temperature field of MEMS humidity sensor is simulated from the ground to 32km altitude by using CFD soft under the boundary condition of fluid-solid coupled heat transfer. Secondly, the numerical analysis model of RH is put forward for solar radiation dry bias (SRDB) correction based on the working principle of the MEMS capacitive humidity sensor and the definition of RH. The results of numerical analysis show that the error of RH caused by solar radiation is nonlinearly increased with the altitude. Meanwhile the errors decrease with the reflectivity of sensor or of solder point increase. The simulation data also indicate that the SRDB can be reduced by improving the reflectivity of sensor or of solder point, adopting the substrate material with high thermal conductivity or choosing the suitable thickness of sensor. However, the SRDB should be corrected, for it still is more than 20% under the low atmospheric pressure. In this paper, the method based on fluid dynamics simulation provides a new way to correct the error of radiosonde MEMS humidity measurement caused by solar radiation heating.
Application of Magnetic Filter Technology in Improving the Precision of a Micro Attitude Reference System
Authors: Yuan Guang Min , Cao Xiao Rui , Zhao Yan Ming , Wang Ping , Xie Jian Bin , Chang Hong Long
Published: May 2015

A micro attitude reference system is vulnerable to overload interference. To solve this problem, a type of Kalman filter was designed on the basis of a geomagnetic technique. Allan variance analysis was used to improve the Sage–Husa adaptive filter algorithm. Attitude error and gyro drifts were used as state variables for adaptive filtering updates, and a three-component magnetic vector was used for adaptive filtering measurement updates. Experimental results show that the pitch accuracy of the attitude reference system with magnetic filter technology working in 2 g vibrations improves by 4.7 times, the roll accuracy improves by 1.5 times, and the heading accuracy improves by 5.4 times. The proposed method can effectively reduce overload interference and ensure angular accuracy.
Presentación
Authors: Caro Isaac , Jiles Susana
Published: May 2015

Presentación
La acción del Estado brasileño en relación a los migrantes bolivianos en Brasil: la cuestión del trabajo (in)documentado, refugio e inmigración económica
Authors: Ranincheski Sonia , Uebel Roberto Rodolfo
Published: May 2015

Desde inicios del siglo XXI Brasil ha estado inserto en una agenda internacional de desarrollo y crecimiento económico, presentando buenas condiciones laborales y de proyección global, representando un puerto de ingreso de variados grupos inmigratorios, incluyendo a los bolivianos, que se insertan cada vez más en la sociedad y economía brasileña—muchas veces ilegalmente— e influenciando el papel del Estado y las relaciones diplomáticas entre el país emisor y el receptor de estos inmigrantes. Esta investigación abordará la acción del Estado brasileño y la inserción de los inmigrantes bolivianos en Brasil por medio de un análisis bibliográfico, documental y estadístico, además de inferirlas puntualidades de esta inmigración en las relaciones Brasil-Bolivia y establecer proyecciones para las dos primeras décadas del nuevo siglo
Regiones extremas chilenas y su invisibilidad económica
Authors: Soza-Amigo Sergio , Correa Loreto
Published: May 2015

En este artículo se constata que las zonas extremas de Chile no poseen una estructura que viabilice un modelo de desarrollo homogéneo respecto a las demás regiones, y que dichas diferencias se manifiestan en sus composiciones demográficas y económicas. La hipótesis central de este trabajo es que las regiones extremas del norte y sur-austral son prácticamente invisibles en el contexto económico nacional. Además, se advierte a través de un análisis input-output, que en el desarrollo endógeno de ambas regiones extremas, Arica y Parinacota no es capaz de generar recursos para satisfacer sus propias necesidades de desarrollo, y que Magallanes y Antártica Chilena al menos ha construido su base económica de manera más formal y diversificada