Stress analysis and fatigue life prediction of a wobble-plate

A five-stage compressor for compressing natural gas is being designed and evaluated. The compressor operates at 1500 rpm with natural gas pressure of 50 psi. This study examines deformation behavior, stress and strain distribution of the wobble plate component of the compressor. Fatigue loading on the wobble plate is computed from the reaction of compressed gas in each of the five cylinders. The highest pressure in the 5th cylinder is 3000 psi. The calculated stress evolution per revolution of the wobble plate is utilized to predict the fatigue lives of the wobble plate. The fatigue life prediction is performed using Brown-Miller algorithm with Morrow mean stress correction method. Results show that the stress is concentrated in the vicinity of the contact region between the guide plate and the polymer guide ball. The highest stress in the wobble plate and the polymer guide ball is 160.4 MPa and 127.8 MPa respectively. The corresponding predicted fatigue life of the wobble plate is 8x108 cycles. A higher stress gradient in the guide ball (max von Mises stress is 3.3 GPa) is predicted when a harder steel ball is employed. This is due to high stiffness of the mating plate/ball surfaces

Differences between supplier development programme of foreign and local Malaysian automotive suppliers

Research into supplier development has raised issues on the buyer’s relationship with the supplier.A buyer with collaborative relationship would have more interest in supplier development.From the viewpoint of the suppliers, buyers who provided assistance could help the suppliers in developing their capability, a situation that might be particularly relevant in developing and emerging countries. The automotive manufacturers have implemented supplier development programmes for their suppliers, both in developed and developing countries.This raises a question on supplier development programmes in developing countries: How do supplier development programmes differ between a local (Malaysian) supplier and a foreign (non-Malaysian) supplier for Malaysian automakers (buyers)? In this research, interviews were conducted at three supplier organisations, of which one was Australian and two were Malaysian, where all three were suppliers for a Malaysian automaker.This study found that the Malaysian and Australian suppliers differed in supplier categories, customisation versus standardised products and buyer involvement.The study suggests that buyer differences with regard to supplier relationship, supplier commitment, type of product and size of supplier organisation play a role in supplier development

No Large Scale Curvature Perturbations during Waterfall of Hybrid Inflation

In this paper the possibility of generating large scale curvature perturbations induced from the entropic perturbations during the waterfall phase transition of standard hybrid inflation model is studied. We show that whether or not appreciable amounts of large scale curvature perturbations are produced during the waterfall phase transition depend crucially on the competition between the classical and the quantum mechanical back-reactions to terminate inflation. If one considers only the classical evolution of the system we show that the highly blue-tilted entropy perturbations induce highly blue-tilted large scale curvature perturbations during the waterfall phase transition which dominate over the original adiabatic curvature perturbations. However, we show that the quantum back-reactions of the waterfall field inhomogeneities produced during the phase transition dominate completely over the classical back-reactions. The cumulative quantum back-reactions of very small scales tachyonic modes terminate inflation very efficiently and shut off the curvature perturbations evolution during the waterfall phase transition. This indicates that the standard hybrid inflation model is safe under large scale curvature perturbations during the waterfall phase transition.Comment: The discussions of quantum back-reactions are improved and new analysis from Eq (84) to (98) are added, new references adde

Radio frequency identification (RFID) technologies for locating warehouse resources: A conceptual framework

Copyright @ 2012 Information Technology SocietyIn the supply chain, a warehouse is a crucial component for linking all chain parties. It is necessary to track the real time resource location and status to support warehouse operations effectively. Therefore, RFID technology has been adopted to facilitate the collection and sharing of data in a warehouse environment. However, an essential decision should be made on the type of RFID tags the warehouse managers should adopt, because it is very important to implement RFID tags that work in warehouse environment. As a result, the warehouse resources will be easily tracked and accurately located which will improve the visibility of warehouse operations, enhance the productivity and reduce the operation costs of the warehouse. Therefore, it is crucial to evaluate the reading performance of all types of RFID tags in a warehouse environment in order to choose the most appropriate RFID tags which will enhance the operational efficiency of a warehouse. Reading performance of active and passive RFID tags have been evaluated before while, semi-passive RFID tag, which is battery-assisted with greater sensitivity than passive tags and cheaper than active tags, has not been examined yet in a warehouse environment. This research is in- progress research and it seeks to (i) provide a general overview of the existing real-time data management techniques in tracking warehouse resources location, (ii) provide an overall conceptual framework that can help warehouse managers to choose the best RFID technologies for a warehouse environment, (iii) Finally, the paper submits an experiment design for evaluating the reading performance of semi-passive RFID tags in a warehouse environment

Spectral atlases of the Sun from 3980 to 7100 {\AA} at the center and at the limb

In this work, we present digital and graphical atlases of spectra of both the solar disk-center and of the limb near the Solar poles using data taken at the UTS-IAP & RIAAM (the University of Tabriz Siderostat, telescope and spectrograph jointly developed with the Institut d'Astrophysique de Paris and Research Institute for Astronomy and Astrophysics of Maragha). High resolution and high signal-to-noise ratio (SNR)CCD-slit spectra of the sun for 2 different parts of the disk, namely for $\mu$~=~1.0 (solar center) \& for $\mu$~=~ 0.3 solar limb) are provided and discussed. While there are several spectral atlases of the solar disk-center, this is the first spectral atlas ever produced for the solar limb at this spectral range. The resolution of the spectra is about \emph{R}~$\sim$~70 000 ($\Delta\lambda$~$\sim$~0.09 {\AA} with the signal-to-noise ratio (SNR) of 400$-$600. The full atlas covers the 3980 to 7100 {\AA} spectral regions and contains 44 pages with three partial spectra of the solar spectrum put on each page to make it compact. The difference spectrum of the normalized solar disk-center and the solar limb is also included in the graphic presentation of the atlas to show the difference of line profiles, including far wings. The identification of the most significant solar lines is included in the graphic presentation of the atlas. Telluric lines are producing a definite signature on the difference spectra which is easy to notice. At the end of this paper we present only two sample pages of the whole atlas while the graphic presentation of the whole atlas along with its ASCII file can be accessed via the ftp server of the CDS in Strasbourg via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via this link \footnote{\url{http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/other/ApSS}}.Comment: Accepted for publication in Ap&SS journal. 11 pages, 10 figures. The full atlas can be accessed via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/other/ApS

Potential for Blue-Gray Water Trade-offs for Irrigation in Small Towns of Pakistan: A Case Study of Farmers' Costs and Benefits in Haroonabad

The growing demand and the competition for fresh water in various sectors suggest that the irrigated agriculture will have to release freshwater for more important and valuable uses. This implies that other options would need to be identified to meet water demands for agriculture. Meeting irrigation requirements through non-conventional water sources is one of the options for agricultural uses. Gray water use for irrigation, a pervasive practice in urban and peri-urban areas of many developing countries, could be one of the solutions. The debate on wastewater irrigation from an environmental point of view is already on, focussing more on human and environmental “safety” aspects. The “value” aspect of the wastewater irrigation remains neglected, however. The irrigation users of untreated wastewater in many parts of the world had already traded off and revealed their preference for gray over blue water decades ago, when the water supply systems in towns and cities were set up. Why they would do it despite the high environmental and health risks associated with its use needs an answer. The paper documents the costs and benefits of wastewater irrigation from users’ point of view, and assesses the potential for real blue water savings in a small town setting in the southern Punjab, Pakistan. The data presented in the paper suggest that wastewater irrigation does lead to blue water savings, and it is profitable for farmers. While its potential is not fully exploited, more focus on appropriate approaches to physical and institutional aspects of wastewater disposal planning and management could make wastewater irrigation more productive, profitable, and safe for individuals as well as for the society as a whole.

Evaluating the reading performance of semi-passive RFID tags to enhance locating of warehouse resources: An experiment design

Copyright @ 2011 8th European, Mediterranean and Middle Eastern Conference on Information Systems (EMCIS 2011)In the supply chain, a warehouse is a crucial component for linking all chain parties. It is necessary to track the real time resource location and status to support warehouse operations effectively. Therefore, RFID technology has been adopted to facilitate the collection and sharing of data in a warehouse environment. However, an essential decision should be made on the type of RFID tags the warehouse managers should adopt, because it is very important to implement RFID tags that work in warehouse environment. As a result, the warehouse resources will be easily tracked and accurately located which will improve the visibility of warehouse operations, enhance the productivity and reduce the operation costs of the warehouse. Therefore, it is crucial to evaluate the reading performance of all types of RFID tags in a warehouse environment in order to choose the most appropriate RFID tags which will enhance the operational efficiency of a warehouse. Reading performance of active and passive RFID tags have been evaluated before while, semi-passive RFID tag, which is battery-assisted with greater sensitivity than passive tags and cheaper than active tags, has not been examined yet in a warehouse environment. This research is in- progress research and it is aiming to perform tests for evaluating the reading performance of semi-passive RFID apparatus to provide an extensive RFID performance comparison for formulating an efficient RFID solution in warehousing environment