AMIRKABIR
Year:2004 | Volume:15 | Issue:57-D|Papers Count:11

Conducting plastic electrodes /lave been developed and investigated for the vanadium redox flow battery. Electrical and electrochemical properties of carbon-polypropylene composite material were evaluated The composite electrode assembly has a matrix layer and an active layer, each performing different function. Since the electrochemical reactions of the redox couples in the battery take place at the active layer, particularly at the interface between the electrolyte and the surface active layer material, its physical, chemical and electrochemical properties are important factors in battery application.

The Riagan porphyry copper system is located in Bam, Southeastern Iran (Kerman Provice),and is associated with diorite/granodiorite to quartz-monzonite of Miocene age that intruded Eocene volcano- sedimentary rocks. Copper mineralization was accompanied by mainly phyllic and less potassic alteration. Field observations and petrographic studies demonstrate that emplacement of the Raigan stock took place in several intrusive pulses, each with associated hydrothermal activity. Molybdenum is reported in any stage of hydrothermal evolution through the system. Due to lack of information, the petrogenesis interpretation is mainly based on the field observation. It seems that early hydrothermal alteration produced a potassic assemblage (orthoclase-biotite) in the central part of the stock, propylitic alteration occurred contemporaneously with potassic alteration, but in the peripheral parts of the stock, and phyllic alteration formed later, overprinting all the earlier alteration (the most majority alteration in Raigan system). The early hydrothermal fluids are represented by high temperature (487 °C to 598 °C), high salinity (up to 61.1 wt % NaCI equiv.) liquid-rich fluid inclusions, and high temperature (397 °C, 401 °C), low-salinity, vapor-rich inclusions. These fluids are interpreted to represent an orthomagmatic fluid which boiled episodically; the brines are interpreted to have caused potassic alteration, containing generation of chalcopyrite. Propylitic alteration is attributed to a liquid-rich, lower temperature (523 °C to 298 °C), Ca-rich, evolved meteoric fluid. Influx of meteoric water into the system, and mixing with magmatic fluid produced deep albitization, and shallow phyllic alteration. This influx also caused dissolution of early formed copper sulfides and remobilization of Cu into the sericitic zone where it was resystemed in response to a boiling-induced decrease in temperature. Supergene alteration was minor and restricted to a thin blanket of Cu-sulfides.

Conducting plastic electrodes have been developed and investigated for the vanadium redox flow battery. It was found that although air oxidation of the felt resulted in a slight decrease in electrical conductivity, a significant increase in activity of the felt was obtained with thermal treatment of the felt. Finally, the performance of a vanadium redox flow cell employing the carbon-polypropylene composite electrode was evaluated and voltage efficiencies as high as95% were achieved at a charge/discharge current density of 20mA.cm-2.

The application of Statistical modelling techniques so called as Stractural Equation Modelling (SEM) to an industrial case, is the main objective of this paper. SEM is a powerful modeling technique that can combine complex path models with latent variables (factors). The basic elements involved in SEM, like factor analysis specially confirmatory kind of it, are illustrated. In a modelling process the conceptual framework of The Impact of CAD/CAM/CAE Virtual Integration on Organization(s) Survival is modeled using SEM. The developed model is tested on using the data from automative manufacturing organizations of IRAN. Symbolic presentation of the theoretical model and testing is done using one of the powerful software of SEM called LISREL.

Quality is an important aspect of a product or service that directly affects the customer Satisfaction level.This is why organizations are after different methods and tools that can help them to improve the quality of products or services they offer to their customers. Quality function deployment (QFD) is a cross-functional planning tool that translates the customers needs into detailed requirements at each stage of product development and product cycle. The basic idea of QFD is to translate the desire of the customer into design or engineering characteristics of a product and, subsequently, into the parts characteristics, the process plans, and the production requirements associated with the manufacturing of product. This paper discusses the use of fuzzy methodology to model the needs of the customers when they state their needs in fuzzy terminology. An example is provided which illustrates the application of the proposed method.

relationships, two stages of hydrothermal alteration and related mineralization within the Anjerd skarn have been identified Thefirst stage (stage I) was produced by the early pulses of Fe-rich magmatically derived fluids, which caused the formation of oscillatory zoned garnets, followed by pyroxene (diopside and hedenbergite) + wollastonite and magnetite at high temperatures (~ 445 °C). The second stage (II) occurred at lower temperature (~ 360 °C) when the system collapsed, and is characterised by lower the temperature minerals like tremolite-actinolite, epidote, quartz, calcite, apatite, titanite, hematite crystallization and copper deposition. It is concluded that the Cu mineralization was due to decreasing and increasing the fo2 and pH respectively, in lower the temperature (< 400 °C) in the last stage of alteration in the Anjerd skarn.A detailed mineralogical study presents that the fluctuations in the At+3/Fe+3 ratio at Anjerd skarns, caused a complex oscillatory zoning from andradite100 to andradite76 grossular24 in the index garnets. Individual zones are typically composed either of near end-member andradite or andradite containing approximately 20 mole % grossular. Introduction of fresh batches of Fe-rich fluid caused crystallization of near end-member andradite garnet since the system was buffered by fluid. TIle source of Al in the system was from Cretaceous marls and limestone sequences, since the Al content available from the magmatic solutions is very low and almost constant. Changes in thermodynamic parameters like fo2 . pH and T witlun the second stage of skarn alteration in Anjerd, caused an economic copper deposition.

Calculation of the initial capital is one of the primary requirements in the feasibility study of industrial projects. In this paper a typical processing plant has been designed for the feed capacity of 500 to 8000 tons per day in sixteen different steps. A mathematical model in the form of Y=exp( a+b.Ln(X)) has been devised that calculates the cost of some of the machines used in these different capacity plants. In all these models Y is the capital cost and X is the most important variable in choosing the machinery. The total capital cost of all these different capacity plants have been calculated by adding the construction make, building etc to the results obtained from these models. A mathematical model is then introduced tllat calculates the total initial capital requirement for sixteen different capacity lead and zinc processing plants. The methods adopted and the models introduced could be used in the design process of such plants and to evaluate the feasibility of such project

The Raigan porphyry system that intruded Eocene volcano-sedimentary rocks is hosted in a diorite/granodioritic to quartz-monzonitic stock. Copper mineralization is esentialy associated with potassic and less sericitic alteration. Based on the fluid inclusion mineral paragenesis and Field relationships, it is concluded that the main copper mineralization at Raigan system occurred in the temperature range of 350-550 °c (with the mode of 450 °C).These data also indicate that the hydrothermal system involved both magmatic and meteoric waters, and boiled extensively. In this research, thermodynamic data are used to delineate the stability fields of alteration and ore assemblages as a function of fs2,fo2, aCr and pH (in the fIXed temperature of 460 °c and the pressure of 550 bars) for the chalcopyrite dissolution and deposition. During potassic alteration (> 550 °C), copper solubility is calculated to have been >100,000 ppm, whereas the copper content of the initial fluid responsible for ore deposition is estimated from fluid inclusion data to have been 1200-2000 ppm. This indicates that the fluid was initially undersaturated with respect to chalcopyrite, which agrees with the observation that veins formed at T>500 ° C and contain rarely chalcopyrite. Copper solubility drops rapidly with decreasing temperature, and at 400 °c is approximately 1000ppm, within the range estimated from fluid inclusion data. At the Raigan porphyry system, the temperature never drops to less than 400 °c degree before all the copper separates from the fluid. These calculations are consistent with observations that the bulk of the chalcopyrite deposited at Raigan system, is hosted by veins formed at approximate temperatures more than 450 ± 60 °c, which according to the previous measurements, it is impossible to have a copper deposit. Other factors that may reduce chalcopyrite solubility are increase in pH, decrease in fo2 and a cr. Based on the calculations of this paper, it is proposed that the Raigan porphyry system formed partly in high temperature, high pH, and decrease in aCr that accompanied boiling. The combination of these factors in high temperatures could seriosly prevent the Raigan system to produce an economic porphyry copper deposit.

JIT production approach requires particular system characteristics in order to enable better response for customer demand as well as the fulfillment of JIT objectives. The paper studies the information system characteristics required for the JIT approach comparing with the requirements for a conventional production system, for instance, an MRP system. An information system requirement pattern for the JIT environment is then developed through this study. Then, considering an industrial production case the pattern is examined and the result are discussed in the paper.

The Persian Gulf is one of the most petroliferous areas. Mesozoic and Tertiary source rocks and crude oils from the Iranian sector of Persian Gulf have been characterized by means of a variety of organic geochemical techniques. Oil fields Investigated Include Resalat, Salman, Sirri and Nousrat In the eastern. part of Persian.Gulf. The Biomarker characteristics (molecular fossils) were combined with other geochemical data to interpret the sources, depositional environments, diagenesis and cat agenesis processes,. migration and alteration. According to the biomarker another geochemical study, oils In the eastern part of Persian Gulf can be classified In two groups.Group 1: include the Sirri and Nousrat oil fields. According to the C28/C29 Sterane and Dia/reg Ste, this group sourced from the Jurassic and lower part of the Cretaceous Carbonate rocks.Group 2: that include Resalat and Salman oil fields, Sourced from the upper Paleozoic Shaly rocks.

Study on the spinning behaviour of polypropylene fibres during rotor spinning is very important and may help us to find the appropriate ways to improve the spinning properties of fibres. In this study, mechanical and thermal damage of PP fibres during the various stages of rotor spinning line is investigated. The breaking strength and surface morphology of processed fibres in carding, drawing and rotor frame were studied and compared with those properties in unprocessed fibres.These studies show that some test fibres are damaged when contact the surfaces with heat due to processing well above the Tg of the fibres. The results of the study on the tenacity and breaking elongation of test fibres indicate that the mechanical properties are also deteriorated. The results of FTIR tests and stress-strain curves show some interstructure changes in some samples, which can be seen as partial changes in the crystalinity and elastic modulus. Investigation on the surface morphology of the damaged fibres shows some localized damaged areas in the form of compressive deformations, melt points, peeling off of the surface, voids and cracks. In general the results of various experiments confirm the occurrence of thermal damage in the rotor spinning process which affects the spinning behaviour inversely.