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Kosmos
Astronomia Astrofizyka
Inne

Kultura
Sztuka dawna i współczesna, muzea i kolekcje

Metoda
Metodologia nauk, Matematyka, Filozofia, Miary i wagi, Pomiary

Materia
Substancje, reakcje, energia
Fizyka, chemia i inżynieria materiałowa

Człowiek
Antropologia kulturowa Socjologia Psychologia Zdrowie i medycyna

Wizje
Przewidywania Kosmologia Religie Ideologia Polityka

Ziemia
Geologia, geofizyka, geochemia, środowisko przyrodnicze

Życie
Biologia, biologia molekularna i genetyka

Cyberprzestrzeń
Technologia cyberprzestrzeni, cyberkultura, media i komunikacja

Działalność
Wiadomości | Gospodarka, biznes, zarządzanie, ekonomia

Technologie
Budownictwo, energetyka, transport, wytwarzanie, technologie informacyjne

American Journal of Engineering and Applied Sciences

Problem statement: Liquefaction was the most hazardous damage during an earthquake. Ground improvement techniques were employed to mitigate liquefaction hazards. Most common methods to improve engineering properties of soils are densification, reinforcement, grouting/mixing and drainage. Among various remedial measures available, installation of columnar granular inclusions is the most widely adopted method for liquefaction mitigation. Approach: Columnar granular inclusions function as drains and permit rapid dissipation of earthquake induced pore pressures by virtue of their high permeability. Results: One of the chief benefits of ground treatment with granular piles is the densification of in situ ground by which the in-situ properties of the ground get modified to mitigate liquefaction potential. Further, the very high deformation modulus and stiffness of the granular pile material provide reinforcement for the in situ soil and offer another mechanism to mitigate liquefaction. The study described briefly the phenomenon of liquefaction and the associated features. A short discussion on various ground improvement methods available for liquefaction mitigation was presented highlighting the importance of columnar inclusions. Construction methods of different granular columnar inclusions like sand compaction piles/ granular piles were discussed briefly. Recent developments in the research of columnar granular inclusions as liquefaction counter measures were presented in relation to physical, numerical and analytical model studies. Conclusion/Recommendations: Columnar granular inclusions were demonstrated to be very effective for liquefaction mitigation in different case studies and research investigations.

http://www.thescipub.com/abstract/10.3844/ajeassp.2009.526.536 2011/01/11 - 03:35

Problem statement: China’s energy consumption is increasing with a high-speed in recent years. Especially since building energy consumption caught pubic eyes and became a crucial problem of society, it forced the public to make estimation in order to reduce energy consumption efficiently. However, it is very difficult to analyze a non-residential building accurately due to China’s statistical collection system and the lack of national surveys. Approach: This study introduced a methodology of estimating various energy consumption factors by building types, energy end-use (electric power, space heating, space cooling and hot water) in each province. The unit energy consumption factors were determined based on sample cities’ data and modification by using software analysis. Take 2006 year for example, the estimation method was introduced. Results: The non-residential building energy consumption in China in 2006 year was estimated by the method above mentioned. Through the result of analysis, we found out that energy consumption of space heating, space cooling and hot water were greatly affected by space Heating Degree Day (HDD), space Cooling Degree Day (CDD) and regional consumer spending per person (Op-c). Conclusion: A series of formulas were obtained. So by using the formulas we can not only estimate the energy consumption now, but also the energy consumption in future. However, this is the first step of our research. It might be hoped that the further surveys and research on energy consumption of China can be done to promote our research result.

http://www.thescipub.com/abstract/10.3844/ajeassp.2010.529.533 2011/01/11 - 03:35

Problem statement: The phenomenon of global warming or climate change has led to many environmental issues including higher atmospheric temperatures, intensive precipitation, increase greenhouse gaseous emission and of course increase indoor discomfort condition. Researchers worldwide collectively agreed that one way of reducing the impact of global warming is by implementing green roof technology which integrates vegetation, growing medium and water proofing membrane on top of the roof surface. However, none of them have ever studied on how much the potted plants on the roof top could contribute to lessen the environmental problems. Therefore, this study investigates the effect of potted plants on flat roof on the indoor temperature inside building in Malaysian climate. Approach: This study emphasized on experimental approach of the room with flat roof. Measurements were conducted in two phases i.e., room with potted plant on the roof and room with bare roof. The measurements were conducted on the same room. Results: The experiment showed a promising result whereby the average indoor temperature dropped between 0.21 and 1.73°C had been observed during the measurements, while average indoor surface temperatures difference between roof with potted plants and bare roof of 7.86°C had been recorded during daytime hour. Conclusion: Potted plants on flat roof had a great potential in reducing the indoor temperature of the room underneath and could contributed to the reduction of energy consumption in building.

http://www.thescipub.com/abstract/10.3844/ajeassp.2010.534.539 2011/01/11 - 03:35

Problem statement: The conventional liquefaction evaluation is based on a deterministic approach. However in this method the uncertainty in the earthquake loading is not properly taken into account. However recent research in this field indicates that this uncertainty in the earthquake loading has to be considered in the liquefaction potential evaluation. Moreover the evaluation of liquefaction return period is not possible in the conventional deterministic methods. This study explained the methods for evaluating the probability of liquefaction and the return period of liquefaction based on probabilistic approach. Approach: In this study the geotechnical data was collected from 450 bore holes in Bangalore, India, covering an area of 220 km2. The seismic hazard analysis for the study area is carried out using Probabilistic Seismic Hazard Analysis (PSHA) and the peak acceleration at ground surface was evaluated for site class-D after considering local site effects. For assessment of site class, shear wave velocity profiles in the city had been obtained using Multichannel Analysis of Surface Waves (MASW) survey. Based on this data the probabilistic liquefaction analysis was done to evaluate the probability of liquefaction in the study area. Based on the performance based approach the liquefaction return period for the study area was also evaluated. Results: The results showed the variation of liquefaction susceptibility for the study area. The corrected standard penetration values required to prevent the liquefaction for return periods of 475 and 2500 years were also presented here. Conclusion/Recommendations: The spatial variation of probability of liquefaction and the factor of safety against liquefaction evaluated using the two methods match well for the study area.

http://www.thescipub.com/abstract/10.3844/ajeassp.2009.537.543 2011/01/11 - 03:35

Problem statement: Whilst at the design stage the various aspects of design impact must be taken into account, the incident solar radiation, insolation, is a key to many environmental aspects of street canyons. In this regard, the configuration of an urban street has a decisive role in magnitude of the solar radiation which it receives on its flank. This study aimed the influence of geometry and orientation of urban street canyon on flank insolation in an arid climate city. Approach: This study approached numerical simulation and employs a computational programme to carry out a 2D simulation within Urban Canopy Layer; (UCL). To enhance the resolution, the simulation condition is based upon accumulative hourly insolation on the daily-basis sun movement for the both solstices as the two extreme days of the year. Results: Geometry has an inverse influence on flank insolation and streets approaching deeper canyons would have lower insolation in both summer and winter. The orientation influence on insolation is to be seen with the season. In winter, orientation effect is analogous to geometry impact and higher inclined canyons would have lower insolation on their flank. In summer, increase in orientation causes variation in flank insolation of which the variation trend is not in the same direction. Conclusion: This study showed that both geometry and orientation influence the solar radiation incident on the street flank and therefore ought to be considered in the design stage where the designers can take full advantages. The increase in geometry or orientation towards deeper canyon and higher inclination respectively, yield insolation reduction excluding for the orientation influence in summer that causes insolation variation.

http://www.thescipub.com/abstract/10.3844/ajeassp.2010.540.544 2011/01/11 - 03:35

Problem statement: Correct evaluation of the earth pressure against retaining structure during earthquake is essential for the safe and economic design of geotechnical structures. Progressive deformation in the backfill and the assumed shape of failure wedge affect the calculated values of seismic earth pressures. However, no research until now is available that considers both of these two factors in an analysis. Approach: In this study, a new analytical methodology was proposed that took into the account the progressive failure of the backfill soil as well as the shape of the failure wedge. A new formulation was first established taking the failure plane as the combination of a curved lower part and a straight upper part. The localized deformation of the backfill was accounted for in the formulation by utilizing the mobilized friction angle and the peak friction angle depending on the locations along the failure surface. The proposed methodology was validated by comparing the calculated results with the established experimental results. Calculations were also performed for different types of wall with various backfill inclinations. Results: The developed methodology could predict the seismic active earth pressure against retaining structure with reasonable accuracy. It could also realistically predict the active failure domain in the backfill soil at the high excitation level, as compared to the pseudo-static solution provided by the well-known Mononobe-Okabe method. Conclusion/Recommendations: It was observed that the Mononobe-Okabe method underestimates the seismic active earth pressure and overestimates the domain of failure zone in the backfill, especially under intense seismic excitation. The proposed methodology, therefore, can contribute greatly towards the economic earthquake resistant design of geotechnical structures.

http://www.thescipub.com/abstract/10.3844/ajeassp.2009.544.558 2011/01/11 - 03:35

Problem statement: The significance of urban design and planning in the tropics lies mostly on its climatic and regional concerns. Among many design parameters, building height is an important parameter which affects thermal climate in the city considerably. This study investigated the effect of building height on outdoor thermal comfort during the daytime in summer in Dhaka, Bangladesh which is a high density city located in tropical climate zone. This study emphasized on pedestrian comfort condition in a planned residential area in the city. Approach: Thermal comfort was assessed in terms of Temperature-Humidity-Index (THI) which uses air Temperature (Ta) and Relative Humidity (RH). Measurements were carried out in a typical summer day. In addition, to simulate the urban thermal climate, a 3D numerical simulation tool ENVI-met was used. Results: Simulated results showed close agreement with the measured data in case of existing canyon and thus the validity of the present numerical simulation was confirmed. Results showed that in case of existing canyon with average building height of 4-5 storied, THI lies in the discomfort level. A canyon was proposed by increasing the building height to 8-10 storied in the existing canyon. In case of proposed canyon, it was found that increased building height provides comparatively comfortable condition than the existing case during day time. Moreover, mean radiant temperature (Tmrt), surface Temperature (Ts) and wind speed were included in the present study to identify the effects of building height on these factors. Conclusion: The present study had an implication on the urban design process to achieve a more comfortable urban environment by mitigating heat stress in summer.

http://www.thescipub.com/abstract/10.3844/ajeassp.2010.545.551 2011/01/11 - 03:35

Problem statement: This study discussed the concept of identity and the role of modernity in shifting towards globalization. The literature study covered definitions of the key words which are modernity, identity and architecture. The definition included description and issues related to the key words, which became a crucial study in identifying factors which influence the concept of change and continuity in architectural identity. Approach: This study adapted a procedure of two measuring scale Syntax analysis and Semantic analysis. The study identified checklist factors which will be used as a measurable factor for the syntax analysis and prepared a proper standardized questionnaire for (Semantic analysis). The aim was to do qualitative analysis to the influence of modernity to the architectural identity throughout the history of architecture. It illustrated the level of modern influence by western and international style that bore with its unprecedented modern concepts in comparison to the accustomed norm of the traditional architecture of the region. Results: This analysis was to evaluate negative impacts on the modern architecture in relation to the local culture, religion and environment. The case study was selected areas influenced by the development of modern buildings in Erbil city, one of the ancient cities in Iraq. Conclusion: The research contribution was to measure the level of modern influence that has damaged the traditional building identity in Erbil City.

http://www.thescipub.com/abstract/10.3844/ajeassp.2010.552.559 2011/01/11 - 03:35

Problem statement: A number of tailings earthen dams have failed during past earthquakes. The failure of tailings dam ultimately results into the release of the stored tailings waste deposit in the surrounding locality. To reduce such damage of tailings earthen dam, a detail method of seismic analysis is very much essential which can be used reliably for the design and construction. Approach: To establish a detail method of static and seismic analysis for a tailings earthen dam, in this study both the static and seismic analysis were performed for a typical section of tailings earthen dam. The whole analysis was performed using various software packages like FLAC3D, TALREN 4, SEEP/W and SLOPE/W. Results: After FLAC3D analysis it was observed that under the seismic loading condition the maximum displacement of the dam is about 66.7 cm, whereas by using the Makdisi-Seed method the maximum displacement was obtained as 57 cm. FLAC3D analysis showed that the base level input acceleration gets amplified with the height of the dam and at the crest level the amplification is about three times. After slope stability analysis under seismic loading it was found that the factor of safety is 0.89, but under the static loading condition the minimum value of factor of safety was obtained as 1.22. Conclusion/Recommendation: From this analysis it was clear that the dam was unsafe under the seismic loading.

http://www.thescipub.com/abstract/10.3844/ajeassp.2009.559.564 2011/01/11 - 03:35

Problem statement: This study presented a method to evaluate the internal stability of reinforced soil structures against tension and pullout modes of failure using pseudo-static method for earthquake conditions. Approach: Using limit equilibrium method and assuming the failure surface to be logarithmic spiral, analysis was conducted to maintain internal stability against both tensile and pullout failure of the reinforcements. For the seismic conditions, factors of safety of all the geosynthetic layers in relation to tension and pullout failure modes were determined for different magnitudes of friction angle of backfill, horizontal seismic accelerations and surcharge load acting on the wall. Results: The efforts had been made to obtain the number of layers, pullout length and total length of the reinforcement at each layer level for the desired safety level against tension and pullout modes of failure. The influence of friction angle of the backfill, horizontal earthquake acceleration and surcharge load on number of layers, pullout length and total length of the reinforcement needed for the stability at each level was discussed. Conclusion/Recommendations: The developed method provided a closed form solution for the active earth pressure acting on the reinforced soil structures using rotational log-spiral failure mechanism under earthquake loading ensuring safety against tension and pullout modes of failure.

http://www.thescipub.com/abstract/10.3844/ajeassp.2009.565.572 2011/01/11 - 03:35

Problem statement: Many people dreamed about a living human in space without the encumbrance of a complex space suit. Unfortunately no scientific research and inventions: How to make it? Approach: Purpose of this research was to initial researching of this problem, necessary conditions, inventions, design needed devices, system and testing them. In this case main problem is how to satiate human blood with oxygen and delete carbonic acid gas (carbon dioxide). Proposed system enabled a person to function in outer space without a space suit and, for a long time, without food. Results: The theory showed that man can be in space without special complex and massive space suite, it is necessary special testing in animals. Current heart-lung apparatus allowed testing this idea. Researcher offered the simple light apparatus and system for astronauts. Conclusion: Biological humanity can only seriously attempt to colonize space if people will have simple apparatus for support their live in space without massive complex space suit. That is useful also in the Earth for sustaining working men in an otherwise deadly atmosphere laden with lethal particulates (in case of nuclear, chemical or biological war), in underground confined spaces without fresh air, under water or a top high mountains above a height that can sustain respiration.

http://www.thescipub.com/abstract/10.3844/ajeassp.2009.573.579 2011/01/11 - 03:35

Problem statement: Ceramic permanent magnets or more commonly known as strontium hexagonal ferrites have been widely used in permanent magnetic materials as they provide high remanence, high coercivity, relatively high energy product and good chemical stability. In this study, we treated factory byproduct from hot-roll and cold-roll steel industry was used as raw material in synthesis of strontium hexagonal hard ferrites. Approach: X-Ray Diffraction (XRD) was employed to confirm the formation of strontium hard ferrite compound. Vibrating Sample Magnetometer (VSM) was used to analyze the magnetic properties of samples prepared. Results: The magnetic properties, namely remanence and coercivity of factory byproduct-derived strontium hard ferrites were compared. The cold-roll-derived strontium hard ferrite showed higher remanence in this study. Conclusion: This implied that cold-roll byproduct was a better candidate to replace hematite in preparation of strontium hard ferrites compared to hot-roll byproduct.

http://www.thescipub.com/abstract/10.3844/ajeassp.2009.580.583 2011/01/11 - 03:35

Problem statement: An error minimization in robot arm dynamics improves operations and performance of production systems. Many contributions have been made in area of robot dynamics since the earliest study more than two decades, but, a number of researchers are still contributing various principles and new techniques for the best use of robots in reality, especially in the field of industry, as this field of study is inexhaustible. This study attempted to analyze the performance of an industrial robot by comparing solutions obtained using RK method and Single-Term Haar Wavelet Series (STHWS) method. Exact solution of system of equations representing arm model of a robot had been compared with corresponding discrete solution at different time intervals. Absolute error between exact and discrete solutions had also been determined to suggest the method of improving performance of a robot. Approach: Haar wavelet had been applied extensively for signal processing in communications and proved to be a useful mathematical tool for dynamical systems. In this study, STWHS method had been used for solving differential equations. Result had been obtained and compared with exact solutions. Results: Error had been compared by exact solutions, RK and STHWS solutions were reported for non-singular systems and estimated as almost zero. The validation had been carried out with reference to earlier research output appeared in this field of study. Conclusion/Recommendations: For robot arm model selected for study, solution obtained by STHWS was found to be accurate from results.

http://www.thescipub.com/abstract/10.3844/ajeassp.2009.584.589 2011/01/11 - 03:35

Problem statement: Modeling thermal radiation with simultaneous buoyancy and forced convection for real gases flowing inside system with complex geometry is a difficult task encountered in engineering applications. Purpose of this study was to research numerically the interaction of mixed convection and thermal radiation in laminar air flow inside an inclined cylindrical duct with Uniform Wall Heat Flux (UWHF). This study highlighted the radiative double effects of water vapor in air flow on thermal and on dynamic fields. Approach: Flow equations and energy balance equation were solved simultaneously with temperature dependant thermophysical properties. An implicit finite difference technique was used to solve mass, momentum and energy equations. In order to take into account the non-gray radiative behavior of water vapor (H2O), a global absorption distribution function model was used to represent the infrared radiative properties. Results: Results were presented in term of temperature, velocity and radiative power fields and of evolution of bulk temperature and Nusselt numbers. Effects of thermal radiation on temperature and on velocity distributions were also examined. Conclusion/Recommendations: It was shown that inclination angle of duct had a significant effect on thermal and dynamic fields especially for thick medium. Radiation strongly affected the velocity profiles. Numerical results were discussed referring to available experimental data in order to improve estimations of engineering parameters.

http://www.thescipub.com/abstract/10.3844/ajeassp.2009.590.602 2011/01/11 - 03:35

The development of effective cooling systems for microprocessors, specifically for CPU and other computer chips, is greatly important due to growth of high speed performance chips, which operate at elevated heat rates. The same issues apply for adjacent units including RAM and HDD also contributing to overall generation of heat inside computer. Problem statement: Conventional cooling system for desktop PC has many problems, especially cooling performance. Lifespan of devices and reliable operation are largely dependent on junction temperature. Total power dissipation of recently introduced, new generation microprocessors had been increasing rapidly, pushing desktop system cooling technology close to its limits. Approach: Present research focused on a system for removal of dissipated heat that combined the advantages of heat pipe and thermoelectric modules. Proposed research presented a numerical analysis of a novel cooling system for electronics. Configuration studied concerns microprocessors and other computer ships. Simulations performed in this research were based on use of computational fluid dynamics and results obtained in terms of cooling efficiencies were compared to those of the traditional cooling. Heat resistance and temperature of each component were investigated in this modeling. Results: Lowest core temperature was found below 75°C and total thermal resistance of cooling system is 0.095°C/W. Conclusion/Recommendations: Proposed cooling systems had sufficient capacity for cooling 200 W heat dissipation. Temperature of proposed cooling system is lower than both existing cooling systems. Temperature of all components, CPU, heat pipe, TEC and heat sink were below 75°C. Thermal resistance characteristic of a cooling system had a major effect on cooling performance.

http://www.thescipub.com/abstract/10.3844/ajeassp.2009.603.610 2011/01/11 - 03:35

Problem statement: Problem of moving a robot through unknown environment has attracted much attention over past two decades. Such problems have several difficulties and complexities that are unobserved, besides the ambiguity of how this can be achieved since a robot may encounter obstacles of all forms that must be bypassed in an intelligent manner. This research had been aimed to develop a system that was able to detect obstacles in a mobile robot's path using a single camera as only sensory input and to achieve the target point in optimized manner. For this reason, algorithm which took total path length and safety into account was developed. Approach: To control movement of robot from a starting to a target point inside the site where obstacles can obstruct the way of robot, real-time software-specially tailored for this purpose-was necessary to develop. To analyze and to process scene images captured by a (vision) camera, camera was installed at the top over the center of site in a way that it covered whole site through which sufficient image information could be delivered. From sequentially captured images that was manipulated through image processing and computer vision, the system built a representative site model, whose ingredients were gridded squares as a result of quantized spatial plane of site and then it began planning the desired routing path. Results: For building a robot path, less computing effort was necessary because grid information was much easier to deal with than pixels and only a minimum amount of stored data of symbolic site model from current and previous state was necessary. Conclusion: Using a quantized spatial domain, a less computational effort was necessary to control movement of robot with the ability of obstacle detection and avoidance.

http://www.thescipub.com/abstract/10.3844/ajeassp.2009.611.619 2011/01/11 - 03:35

Problem statement: Real-time Transport Control Protocol (RTCP) protocol has been the subject of various criticisms due its problematic performance in large-scale networks. S-RTCP is a protocol with high potential as it has proved to be able to solve many problems of RTCP. It has numerous flaws on its own. This study aimed at dealing with flaws of S-RTCP and improving it in terms of stability and packet loss. Approach: A new proposed scheme was designed. Modifications included designing multi-manager scheme, improving parent-seeking procedures, reducing distribution of request packets, reforming the design to be independent from TTL, adding methods to check on sanity of manager nodes. This study considered packet loss ratio of below 2% as desirable. Results: ER-RTCP comparing to legacy RTCP in terms of packet loss using NS-2 in four different scenarios revealed improvements between 73 and 88% for various scenarios. It also kept packet loss rate below 2% for all scenarios. Comparison of ER-RTCP to S-RTCP showed that based on different α (stability of each single manager) values, ER-RTCP was more stable as it showed more resistance to entire scheme breakdown (β). ER-RTCP's parent-seeking procedure, as modeled scenario revealed a packet generation reduction of 97%, compared to S-RTCP’s. In occurrence of parent AG leave or loss, ER-RTCP reduced request packet generation by 95%. Allowance of AG dismissing in ER-RTCP, avoided occurrence of packet loss, as sample scenario showed S-RTCP experiencing packet loss of 3.5% while ER-RTCP kept packet loss at zero in theory. Conclusion: Proposed design improved S-RTCP in terms of reduction of packet loss and stability.

http://www.thescipub.com/abstract/10.3844/ajeassp.2009.620.627 2011/01/11 - 03:35

Problem statement: Current world market force the manufacturing sectors to develop high quality product and process design with minimum possible cost. About 80% of problems in production units may be attributed to 20% of design tolerance causes. While design typically represents the smallest actual cost elements in products (around 5%), it leverages the largest cost influence (around 70%). So design engineers continuously stumble upon problem of design for high quality performance with lower cost. Objectives of this study where to: (i) simultaneous selection of design and manufacturing tolerance (ii) minimization of total cost (sum of the manufacturing cost and Taguchi’s asymmetric quality cost) (iii) minimum cost and its machining tolerance. Approach: Rotor key base assembly was considered as case study to optimize the minimization of assembly total cost and machining tolerance. New global nonlinear optimization techniques called pattern search algorithm had been implemented to find optimal tolerance allocation and total cost. Results: In this study minimum cost arrived was 45.15 Cr and its corresponding tolerances for machining process turning, drilling, face milling, face milling and drilling where 0.063, 0.0508, 0.2127, 0.2127, 0.2540 mm respectively at worst case conditions. Conclusion: Results indicated that optimization by integer programming, sequential quadratic programming and exhaustive search, nonlinear programming, genetic algorithm, simulated annealing, fuzzy logic, number set theory and Monte Carlo simulation did not give much least total cost and also predicted that pattern search algorithm was robust method. Second the method, generally termed as concurrent tolerance synthesis was well suited for engineering environment, where high quality products with low total cost were designed and manufactured.

http://www.thescipub.com/abstract/10.3844/ajeassp.2009.628.634 2011/01/11 - 03:35

Problem statement: Maximum Likelihood (ML) decoding has been applied for the uplink ofappr a Multi-Carrier Code Division Multiple Access (MC-CDMA) system based on Orthogonal Frequency Division Multiplexing (OFDM). Multiple-Input Multiple-Output (MIMO) channel from k users, which moves at vehicular speed, to the Base-Station (BS) is time-varying. For time-varying channels, Sphere Decoding (SD) was introduced to perform ML decoding. Whereas, computational complexity of SD (due to a QR-factorization for each symbol), is nevertheless high. Modified SD had been proposed to achieve near optimum solutions that called Subspace-Sphere Decoder (SPSD). Approach: Proposed algorithm was based on subspace and orthogonal projection with very small dimensionality as robustness scheme in an iterative Multi-User Detection (MUD) and Parallel Interference Cancelation (PIC) method. Results: This approach had been achieved intense reduction of computational complexity for time-varying channel via one and more than one order of magnitude at channel estimation and multiuser detection respectively. Furthermore, SPSD was robustness to channel estimation error (about 3.8 dB) as compared to the representative counterparts in literature. Conclusion: Effectiveness of proposed method was demonstrated by simulations.

http://www.thescipub.com/abstract/10.3844/ajeassp.2009.635.642 2011/01/11 - 03:35

Problem statement: At present time gas pipelines are designed from steel and located on ground surface. That is very expensive and building requests a lot of time. Research and utilization of an old author idea: Design of new cheap aerial pipelines, a large flexible tube deployed at high altitude through neutral seas, for delivery of natural (fuel) gas, water and other payload over a long distance is delineated. Approach: A lift force of 1 m3 of methane equals approximately 0.5 kg (1 pound). The lightweight film flexible pipeline can be located in air at high altitude and, as such, did not damage the environment. Using the lift force of this pipeline and wing devices payloads of oil, water, or other fluids, or even solids such as coal, cargo, passengers can be delivered cheaply at long distance. Results: Researcher showed: This aerial pipeline dramatically decreased the cost and time of construction relative to conventional pipelines of steel which saved energy and greatly lowers the capital cost of construction. Article contained a computed project for delivery 24 billion m3 of gas and tens of million tons of oil, water or other payload per year. Conclusion: Design of new cheap aerial pipelines, a large flexible tube deployed at high altitude, for delivery of natural (fuel) gas, water and other payload over a long distance (neutral sea) was delineated. The offered idea an aerial pipe line was researched. It was shown new pipelines radically decreased pipeline cost and construction time. Using the lift force of this pipeline and wing devices payloads of oil, water, or other fluids, or even solids such as coal, cargo, passengers can be delivered cheaply at long distance. This pipeline and wing devices also allowed to delivery the other goods.

http://www.thescipub.com/abstract/10.3844/ajeassp.2009.643.654 2011/01/11 - 03:35

Problem statement: RF MEMS switch is one of MEMS area that creates devices that have great potential to improve the performance of communication circuits and systems and enables the realization of micro size mechanical switches embedded in electronics devices. The low voltage switches are necessary due to their compatibility of standard IC technology in RF application and microelectronics systems. In realizing MEMS switches with low actuation voltage, spring constant of beam must be reduced. Design and simulation of capacitive RF MEMS shunt switches with regards to the pull in voltage were presented. Approach: Design and simulation had been done by using commercial simulation package, CoventorWare 2006. Several switches were designed with different meander spring beams to obtain lower voltage actuations using Architect Module in CoventorWare 2006. Results: Results verified with Finite Element Method (FEM) and simple mathematical modeling. Each design gave different voltage actuations. The lowest actuation voltage simulated was 1.9 V. Average difference of simulated and calculated values was about 16%. This is because no fringing field was included in calculation. Finite Element Method (FEM) analysis was done for switch C. Results showed that lower voltage can be obtained by using serpentine spring which lowers the spring constant and pull-in voltage as well. The lower pull-in time was primarily due to its very small dimensions and mass Conclusion: Low-voltage capacitive shunt RF MEMS switches were designed and simulated. These switches had actuation voltages of 1.9-7.0 V depending on the serpentine design. The other performance particularly switch C had a pull-in time of 15 µ sec after a voltage of 0-20 V was applied and the resonant frequency is 3153.1 Hz.

http://www.thescipub.com/abstract/10.3844/ajeassp.2009.655.660 2011/01/11 - 03:35

Problem statement: The aim of this research was to study the effect of Sr substitution on structure and thermal diffusivity of Bal-xSrxTiO3 ceramic at room temperature. Approach: Structural and thermal diffusivity of Ba1-xSrxTiO3 were studied by performing X-ray diffraction and photoflash measurements. The effects of Sr substitution on the structure and on the thermal diffusivity of Ba1-xSrxTiO3 (0≤x≤1) were investigated. All samples were prepared by standard solid state reaction technique. Results: The results showed that by substituting of Ba2+ ion with the Sr2+ the crystallite size decreased. The effect made the thermal diffusivity of Ba1-xSrxTiO3 decreased from 11.30x10-3 cm2 sec-1 (for BaTiO3) to 6.467x10-3 cm2 sec-1 (for SrTiO3) as x varied from 0-1. Conclusion: This study showed a significant effect of structure on thermo-physical property of materials.

http://www.thescipub.com/abstract/10.3844/ajeassp.2009.661.664 2011/01/11 - 03:35

Problem statement: Fine blanking process is a high precision process and worldwide in developed countries. Since specimen does not occur fracture on the cutting edge and it is not necessary to decorate again in the finishing process for the fine blanking which can be reduced some operation steps. For example, if chain wheel of motorcycle is produced by conventional blanking, it needs nine steps. But, if it is produced by fine blanking, it requires only three steps. With these reasons, fine blanking is boom for the metal forming industry in Thailand. But, due to some mechanical properties for some kinds of metal such as low elongation or imperfect microstructure, it is not cut by using fine blanking directly. Approach: Objective of this research was to investigate microstructure of specimen for fine blanking process in order to avoid fracture surface on blank. The optimum condition will result in higher elongation while having small decrease in tensile strength. The circular specimen with diameter of 16 mm and thickness of 2 mm was chosen. Material was steel which contains 0.45% carbon. Results: Microstructures contained pearlite and ferrite grains. The grains sizes were expanded with temperature of heat treatments at 700, 800 and 900°C, respectively, for 1 h. The specimen exposes to heat treatment in each temperature results in the increase of overall shear surface and the decrease of fracture surface when compared with no heat treatment. This is due to no appearance of strain hardening. For the microstructures exposed to heat treatment at 700°C for 10-20 h were almost spherroidite. It revealed that facture surface became shear surface after heat treatment over 10 h. Conclusion/Recommendations: The changes of microstructure for 0.45% carbon steel significantly affected to the overall shear and fracture surface and yield strength due to increasing of spherroidite, thus fracture was decreased with time.

http://www.thescipub.com/abstract/10.3844/ajeassp.2009.665.668 2011/01/11 - 03:35

Problem statement: Accuracy and stability of many systems in chemical and process industries which has Two-Input Two-Output (TITO) is one of the key factors of process which have cross coupling between process input and output. Approach: Unlike traditional neural network weight adaptation using gradient descent method, Particles Swarm Optimization (PSO) technique was utilized for adaptive tuning of neural network weights adjustment and fine tuning the controller’s parameters. Design approach for controlling liquid levels of Coupled Tank TITO system by using hybrid PI-Neural Network (hybrid PI-NN) controllers. Results: Tuning method for parameters of improved hybrid PI-NN controller was also discussed. Conclusion: Performances of proposed method also compared with PID-NN controllers, it was shown that hybrid PI-NN controller exhibited better performance in terms of transient response analysis.

http://www.thescipub.com/abstract/10.3844/ajeassp.2009.669.675 2011/01/11 - 03:35

Problem statement: The surge phenomenon in the centrifugal compressor, the non-linearities and uncertainties of the compression system make it impossible to use a conventional controller over a wide range of operation. Approach: A new dual fuzzy controller for nonlinear model of compression system was proposed in this study. This fuzzy controller was designed that consisted of active surge control and phase control without any explicit system models, but driven in human thinking mechanism. Results: Simulation example of compression system was given to demonstrate the validity of proposed control scheme. It was shown that fuzzy controller can be simplified and good tracking control performance can be achieved by choosing appropriate fuzzy roles. But, the dual fuzzy controller can successfully intervene in control surge of compression system. Conclusion: This new fuzzy control methodology suggested in this study reproduced well main characteristics of turbo compressor dynamic model developed by Moore and Gretzer and give place to a more precise and easy to handle representation. It is about an inaccuracies reproducing with a certain degree of satisfaction of real process without being as much complex.

http://www.thescipub.com/abstract/10.3844/ajeassp.2009.676.682 2011/01/11 - 03:35

Problem statement: Researcher offered a new nuclear generator which allowed to convert any matter to nuclear energy in accordance with Einstein equation E = mc2. The method was based upon tapping the energy potential of a Micro Black Hole (MBH) and Hawking radiation created by this MBH. Researcher did not meet the idea and its research in literature to develop the method for getting a cheap energy. Approach: As is well-known, vacuum continuously produced virtual pairs of particles and antiparticles, in particular, photons and anti-photons. MBH event horizon allowed separating them. Anti-photons can be moved to MBH and be annihilated, decreasing mass of MBH, resulting photons leave the MBH neighborhood as Hawking radiation. The offered nuclear generator (named by Researcher as AB-generator) utilized Hawking radiation and injected the matter into MBH and kept MBH in a stable state with near-constant mass. Results: AB-generator can be produced gigantic energy outputs and should be cheaper than a conventional electric station by a factor of hundreds of times. One also may be used in aerospace as a photon rocket or as a power source for many vehicles. Conclusion: Many scientists expect Large Hadron Collider at CERN may be produced one MBH every second. A technology to capture them may be developed; than they may be used for the AB-generator.

http://www.thescipub.com/abstract/10.3844/ajeassp.2009.683.693 2011/01/11 - 03:35

Problem statement: Quantum key distribution provides unconditional security guaranteed by the fundamental laws of quantum physics. Unfortunately, for real-life experimental set-ups, which mainly based on faint laser pulses, the occasional production of multi-photons and channel loss make it possible for sophisticated eavesdroppers to launch various subtle eavesdropping attacks including the Photon Number Splitting (PNS) attack. The decoy state protocols recently proposed to beat PNS attack and to improve dramatically distance and secure key generation rate of Quantum Key Distribution (QKD). Approach: Objective of this study was experimental implementation of weak decoy + vacuum states QKD for increasing the performance of QKD system. To show conceptually how simple it was to apply the weak decoy + vacuum state idea to a commercial QKD system, we chosen ID-3000 commercial quantum key distribution system manufactured by id quantique. To implement the weak decoy + vacuum state protocol, we had to add some new optical and electronics components to id quantique and to attenuate each signal to the intensity of either signal state or weak decoy or vacuum state randomly. Results: In our implementation, the attenuation will be done by placing a VOA (variable optical attenuator) in Alice’s side. Specifically, our QKD system required the polarizations of 2 pulses from the same signal to be orthogonal. Therefore the VOA must be polarization independent so as to attenuate the two pulses equally. The VOA utilized in experiment to attenuate signals dynamically was Intensity Modulator (IM). We had implemented weak + vacuum protocol on a modified commercial QKD system over a 25 km of telecom fibers with an unconditionally secure key rate of 6.2931x10-4 per pulse. Conclusion: By making simple modifications to a commercial quantum key distribution system, we could achieve much better performance with substantially higher key generation rate and longer distance than QKD system without decoy state.

http://www.thescipub.com/abstract/10.3844/ajeassp.2009.694.698 2011/01/11 - 03:35

Problem statement: Filters are widely used in various applications including communications, electronics and biomedical engineering. The performance and size of the filter is of interest especially in chip implementation. A switched-capacitor low-pass filter was designed and simulated using a 0.18 µm 1P6M CMOS technology. Approach: This circuit design offered obvious advantages in increasing the stopband attenuation, reducing passband ripple and achieving accurate frequency response. Results: This circuit achieved 53 dB stop band attenuation, less than 0.1 dB passband ripple, a 5 KHz cut-off frequency, a 100 KHz stopband frequency and consumes 6 mW from a 2 V power supply. Conclusion: The proposed design is very suitable for the realization of analog signal processing blocks in complementary MOSFET integrated circuits.

http://www.thescipub.com/abstract/10.3844/ajeassp.2009.699.702 2011/01/11 - 03:35

Problem statement: Solving the state assignment problem means finding the optimum assignment for each state within a sequential digital circuit. These optimum assignments will result in decreasing the hardware realization cost and increasing the reliability of the digital circuit. Unfortunately, the state assignment problem belongs to the class of nondeterministic polynomial time problems (NP complete) which requires heavy computations. Different attempts have been made towards solving the problem with reasonable recourses. Approach: This study presented a methodology for solving the state assignment problem, the methodology conducted a neighborhood search while using a heuristic to determine the fitness of solution. To avoid being trapped at a local optimum solution, a metaheuristic (simulated annealing) was utilized for deciding whether a new solution should be accepted. A case study was included to demonstrate the proposed procedure efficiency. Results: The proposed approach finds the optimum assignment for the case study. Conclusion: In this study, we explored the usage of a stochastic search technique inspired by simulated annealing to solve the problem of the state assignment problem. This proved the efficiency of the methodology.

http://www.thescipub.com/abstract/10.3844/ajeassp.2009.703.707 2011/01/11 - 03:35

Problem statement: With emphasis on a cleaner environment and efficient operation, vehicles today rely more and more heavily on electrical power generation for success. Approach: Mathematical modeling the components of the HEV as the three phase induction motor couple to DC motor in hybrid electric vehicle was introduced. The controller of Induction Motor (IM) was designed based on input-output feedback linearization technique. It allowed greater electrical generation capacity and the fuel economy and emissions benefits of hybrid electric automotive propulsion. Results: A typical series hybrid electric vehicle was modeled and investigated. Conclusion: Various tests, such as acceleration traversing ramp and fuel consumption and emission were performed on the proposed model of 3 phase induction motor coupler DC motor in electric hybrid vehicles drive.

http://www.thescipub.com/abstract/10.3844/ajeassp.2009.708.712 2011/01/11 - 03:35

Problem statement: Most concepts of linear engines were constructed as opposed pistons with complicated control devise to drive the engines. The advantage of the engines was their high overall efficiency. Approach: Although the efficiency was higher than conventional engine, however, it did not be applied yet, because the design of these engines was not only difficult to fabricate, but also it has little chance to compete the traditional engines in the market. Spring is adopted as a return force of the piston movement technique. Results: The unique of using spring as return cycle is the main characteristic of these engines. However, stroke of the engine is not constant as in the traditional engine. The problem is that, the expansion stroke is depending on thrust force of piston. On the other hand, the engine needs to operate in variable speed and load. This study is a prediction of the performance of both rotational and linear engines. Conclusion/Recommendations: The result of the examination can be used as return cycle design data of a single cylinder linear engine with spring device. As a result, the spring mechanism can be adopted to be used as return cycle in linear engine.

http://www.thescipub.com/abstract/10.3844/ajeassp.2009.713.720 2011/01/11 - 03:35

Problem statement: To distinguish the activities of the network traffic that the intrusion and normal is very difficult and to need much time consuming. An analyst must review all the data that large and wide to find the sequence of intrusion on the network connection. Therefore, it needs a way that can detect network intrusion to reflect the current network traffics. Approach: In this study, a novel method to find intrusion characteristic for IDS using decision tree machine learning of data mining technique was proposed. Method used to generate of rules is classification by ID3 algorithm of decision tree. Results: These rules can determine of intrusion characteristics then to implement in the firewall policy rules as prevention. Conclusion: Combination of IDS and firewall so-called the IPS, so that besides detecting the existence of intrusion also can execute by doing deny of intrusion as prevention.

http://www.thescipub.com/abstract/10.3844/ajeassp.2009.721.725 2011/01/11 - 03:35

Problem statement: Despite intensive research efforts on CO2 transfer, mathematical models that describe the dependence of the CO2 transfer rate on the pH and the degree of rate enhancement due to CO2 chemical reactions remain unavailable. Approach: Such models are essential for assessing and accurately describing the progress of the CO2 transfer process. Results: In this study, an alternative view of CO2 transfer with chemical reactions was used to develop simple mathematical models to describe the pH dependence and degree of enhancement of the CO2 transfer rate. In the alternative view, the driving force for CO2 transfer was described in terms of the differences in the concentrations of the various carbonic species in the bulk liquid (i.e., ΔCΔt(H2CO*3), , ΔCΔt(HO-3) and ΔCΔt(CO2-3) ) in time (i.e., between time, t, and the time when equilibrium is achieved, tEq) rather than in terms of the concentrations gradients across the liquid film. Using the concentration differences in time, simple mathematical models describing the pH dependence of the CO2 transfer rate and the contributions of the various carbonic species to the rate were formulated. Furthermore, the degree of CO2 transfer rate enhancement due to CO2 reactions in water was considered proportional to the sum of the rates of HCO-3 and CO2-3 transfer. Conclusion/Recommendations: The mathematical models were tested using data from batch and continuous-flow CO2 transfer experiments, and the results revealed that the mathematical models explained the experimental data in an excellent manner.

http://www.thescipub.com/abstract/10.3844/ajeassp.2009.726.734 2011/01/11 - 03:35

Problem statement: Safety culture is a complex structure in an organization that includes values and attitudes, most of which are potentially changeable and related to actual accident behavior. In this study, the components of safety culture included organizational commitment, management involvement, employee empowerment, reporting system and rewarding system. Approach: The numbers of occupational injuries in industries have steadily increased during recent years. The major objectives of this study were to evaluate the safety culture and to analyze the difference in safety culture in the metal products industry in Iran (Guilan province) with regard to companies’ age. Metal products industry was chosen because of the higher occupational injuries rates amongst the industries in Iran. Results: The companies were chosen based on their age. A total of 714 respondents from 14 companies participated in the survey. The method used in this study was a questionnaires quantitative type based on a Lickert scale and the data collected were analyzed statistically. The one-way ANOVA was used to test for significant difference in safety culture in the metal products industry with regard to companies’ age. The results showed that safety culture was not strong based on the mean for average score of 2.58 which was less than 3 compared to the possible maximum of 5. One-way ANOVA analysis revealed that there was a significant difference among safety culture with respect to companies’ age. New companies had stronger safety culture compared to older one. Conclusion: Based on the findings the hypothesis of this study is accepted. This study also indicated that the safety culture in the metal products industry in target population group was not strong however, can be improved through improvement of its five components.

http://www.thescipub.com/abstract/10.3844/ajeassp.2009.735.742 2011/01/11 - 03:35

Problem statement: With the advent of the advanced technology and the need for more advanced equipment, the current progress and development of electronic instruments stimulate more interest and efforts for more innovative ideas and better designs. Many real world physical values, such as sounds, temperature, pressure and humidity, can be measured as analog or continuous signals. However, to process these signals by computers or digital equipments, we need first to convert these analog signals into digital or discreet signals. Approach: There are many types of Analog-to-Digital Converters (ADCs) which can be classified according to the concept on which they were designed. For example, there are charge-coupled A/D converter, digital-ramp A/D converter, successive approximation A/D converter, voltage-to-frequency A/D converter, Delta-Sigma A/D converter, Flash A/D converter and some of these converters require the use of Digital-to-Analog Converters (DACs) and/or analog comparators and some logic modules. In some other cases, many analog comparators are needed to perform the conversion. We are trying to use a different approach that reduce the design complexity and improve the measurement quality by using the double-slope integration concept. Result: The new design does not require the use of a DAC module, nor does it need to use many analog comparators to do the conversion. Conclusion: The advantage of the new design would contribute to the simplicity of the design, enhance its reliability and guarantee the linearity of the conversion process that leads into better quality instruments.

http://www.thescipub.com/abstract/10.3844/ajeassp.2009.743.749 2011/01/11 - 03:35

Problem statement: Damage due to corrosion is a significant problem worldwide. Countries around the world have estimated that the cost of corrosion to their national economies to be 3-4% of their gross national product. Approach: Design and implementation a new steel piling of the Corrosion Management Program (CMP) in Al-Zubare harbor. Corrosion management algorithm can be divided into three major phases. Phase 1 of the program is the programmatic assessment of the project. Phase 2 of the program involves physical assessment and actual remediation. Phase 3 of the program mainly deals with future monitoring of the repaired structure. Results: The CMP included activities performed to mitigate corrosion, to repair corrosion-induced damage and to replace the structures that are badly corroded. Installation and maintenance requirements are identified.Conclusion: The data was collected from the tide table for Al-Zubare Harbor in the year 2004. The highest tide of the year would fall on 17 October 2004 at 1.05 am with level 3.5 m, while the lowest tide of the year would fall on 3 July 2004 at 5.13 am with level 0m. The detection results show that this program is feasible and effective.

http://www.thescipub.com/abstract/10.3844/ajeassp.2009.750.753 2011/01/11 - 03:35

Problem statement: Although the traditional metering system and method for controlling flow is generally safe, reliable and robust, it does suffer certain drawbacks, such as limited accuracy and the ability to implement complex reactive rate designs. Hence, there is a need for a circuit and method of increasing metering accuracy, as well as the position control accuracy for variable flow rates, without further reliance on mechanical tolerances. An essential component for an electronic meter is a database and method of communication to obtain the required measurements and to program the meter for any additional needed values. Flexibility is added to such meters by using wireless communication circuits and protocols, which will enable reading of multi-devices from the same source point. Approach: To collect data, critical quality of service and carry out analysis, wireless flow meter reading system is designed, tested and implemented. The hardware and software in the designed system work together, to wirelessly receive readings from meters and then process it in order to obtain an accurate reading for the measured flow. The system makes use of modern communication algorithms and techniques. Also, the system allows for history tracing and analysis. The interfacing hardware uses two-way wireless optical interface to flow meter device. Results: The Hardware and Communication Protocol tested successfully and provided sufficient and accurate data for flow measurements analysis, presented in this research. Conclusion: Such hardware-software arrangement is considered a core for mobile meter reading and control with possibility to add intelligent security algorithms.

http://www.thescipub.com/abstract/10.3844/ajeassp.2009.754.758 2011/01/11 - 03:35

Problem statement: Compressive residual stress induced by surface treatment such as shot peening increased component’s fatigue life. However the initial induced residual stresses relax during component operating life and it is important to consider the relaxation in the design. Approach: In this study, a 2024-T351 aluminum alloy specimens were shot peened into three shot peening intensities condition to induce compressive residual stresses. Then fatigue test for two loads was performed for the 10, 1000 and 10000 cyclic loads. The initial residual stresses at the initial condition and after 10, 1000 and 10000 cycle of fatigue loading were measured using X-ray diffraction method. Results: The results showed that the relaxation of the residual stress for the load 15.5 kN is less than the relaxation of the load 30 kN for the three shot peening intensity. The maximum relaxation for load 15.5 kN is 46% of the initial residual stress at 10000 cycles for intensity 0.009 A while the maximum relaxation for load 30 kN is 54% at 10000 cycles for the intensity of 0.0054% A. this result indicated that the residual stress relaxation depended on the load amplitude. Conclusion: The initial residual stress did not remain stable during the component’s fatigue life. Within the second phase relaxation, micro-plastic strains accumulating from cycle to cycle. The residual stress relaxation for second phase is in logarithmic relationship.

http://www.thescipub.com/abstract/10.3844/ajeassp.2009.759.763 2011/01/11 - 03:35

Problem statement: For predicting workability and hardened properties of Self-Compacting Concrete (SCC) no well known explicit formulation. Approach: Statistical models were carried out to model the influence of key mixture parameter (cement, water to powder ratio, fly ash and super plasticizer) on hardened properties affecting the performance of SCC. Such responses included compressive strength at 3, 7 and 28 days and modulus of elasticity. Thirty one mixtures were prepared to derive the numerical models and evaluate the accuracy. The models were valid for a wide range of mixture proportioning. Results: The research presented derived numerical models that can be useful to reduce the test procedures and trials needed for the proportioning of self-compacting concrete. The qualities of these models were evaluated based on several factors such as level prediction, residual error, residual mean square and correlation coefficients. Conclusion: Full quadratic models in all the response (compressive strength at 3,7 and 28 days and modulus of elasticity) showed high correlation coefficient (R2), adjusted correlation coefficient, less level of significant and sum of square errors from the four predictions models (linear, interaction, full quadratic and pure quadratic) were developed.

http://www.thescipub.com/abstract/10.3844/ajeassp.2009.764.770 2011/01/11 - 03:35

Problem statement: Inadequate knowledge of electromagnetic field emitted by mobile phones and increased usage at close proximity, created a lot of skepticism and speculations among end users on its safety or otherwise. Approach: In this study, near field electromagnetic field radiation measurements were conducted on different brand of mobile phones in active mode using a tri-axis isotropic probe and electric field meter. Results: The highest electromagnetic field exposure was recorded when the mobile phones are at outgoing call mode and backing the probe, which is higher in comparison to ICNIRP guidelines for exposure to general public. Conclusion: According to this finding, some mobile phones electromagnetic field radiation were found to be lower than the ICNIRP guidelines while some were far above the guidelines. Electromagnetic field intensity however, depends on the mode of operation and proximity of the mobile phones to the end user; hence it is safer to use mobile phones at SMS mode.

http://www.thescipub.com/abstract/10.3844/ajeassp.2009.771.774 2011/01/11 - 03:35