AMIRKABIR
Year:2008 | Volume:18 | Issue:67-D|Papers Count:13

A viscoelastic model has been developed to predict the creep behavior of plain woven fabrics using the yarn creep data and the structural parameters of the fabric. The model has been used to obtain theoretical creep data for fabrics with different weft densities and these data have been compared with experimental creep data. It has been observed that by increasing the weft density the fabric's creep decreases.

A field experiment in 2004 and 2005 was conducted at Cotton Research Institute of Iran (CRI), (54° 16¢ , 36° 51¢, 13.3m above sea level). Water resources can be stretch using Sprinkler Irrigation systems, which are highly efficient when properly designed and managed. Cotton pollen and seed cotton is highly sensitive to water. This study was investigated the effect of Sprinkler irrigation programs on Okra-leaf Cotton quality. Four different Irrigation treatments with three replication on Randomized Complete Block were studied. The amount of water used was based on class-A pan evaporation: 100% (T1), 70% (T2), 40% (T3) of cumulative class-A pan evaporation and No Irrigation or rain field (T4). Each plot size was 144m2 with 6m spacing and Si-okra variety-was planted at 80*20 Cm spacing. The plants were harvested  by hand twice. Seed cotton was collected at harvest time, processed at the research gin and sent to the Fiber Technology Laboratory of Iran for fiber evaluation. There were significant different between Irrigation treatment and Earliness, Fiber length and Micronaire. The T4 had Maximum Water Use Efficiency (WUE=11Kg/ha.mm) and earliness (92%) but minimum Fiber length (28.9mm). The T2 had maximum fiber length (31.1mm), Strength value (30.5gr/tex), Elasticity (7.0%) and moderate WUE(9.1%) and total yield (3181Kg/ha).

The Precise prediction of polypropylene synthesized by heterogeneous Ziegler-Natta catalysts needs good knowledge of parameters affecting on polymerization. Molecular weight and molecular weight distribution are among important characteristics of a polymer determining physical-mechanical properties. Broadening of molecular weight distribution is an important and well known characteristic of polypropylene synthesized by heterogeneous Ziegler- Natta catalysts, So it is important to understand the origin of broad molecular weight.Two main factors in broadening molecular weight, namely mass transfer resistances and multiplicity of active sites, are discussed in this paper and a model including these factors is presented. Then we calculate molecular weight and molecular weight distribution by the model and compare our results with experimental results in open literature. Also the effect of the amount of hydrogen on molecular weight and molecular weight distribution is studied by the model.

The most significant objective of this paper is to bring to light the relationship between the scanner device-dependent color space and the device independent CIE color space. The scanner characterization was done based on neuro-fuzzy techniques. To show the usefulness of the proposed method, we performed some simulations. The experimental results are very promising. It should be noted that the new method outperforms the previous methods such as polynomial regression and neural network techniques.

Matrix/fracture permeability and s play paramount role in the sensitivity analysis and therefore the history matching of cumulative oil production and production rate of carbonated fractured reservoirs. In this study, the influence of these parameters upon cumulative production and production rate of an Iranian fractured reservoir were studied by the usage of a simulator. The aforementioned range of matrix/fracture permeability and s for the studied reservoir were one tenth to twice of the permeability and s of the matrix/fracture permeability and s which used in the history matching during the reservoir simulation.Results show that changing the matrix/fracture permeability and s greatly affect the cumulative production as well as the production rate. Also, sensitivity analysis reveal that, the variations in cumulative production and production rate happen in a limited range of matrix/fracture permeability and s .

The relationship between the flexural rigidity of standard warp knitted fabrics and fabric and yam parameters, such as wale and course spacing, underlap length of the front and back guide bars, yam bending rigidity, etc., is discussed. In this study, a mechanical model for the bending behaviour of the warp knitted fabrics is also presented. In theoretical analysis, the knitted fabric loop structure is assumed to consist of a series of straight and skew yam simulating legs and underlaps. The estimation of fabric bending rigidity is based on summing up the bending rigidity of the straight and skew yams that found by energy method with taking into account of rigid region lying in the direction of bending. The estimated values from this model are compared with experimental results obtained on a developed automatic cyclic pure bending tester.Comparison with experimental and theoretical data shows reasonable agreement between predicted and measured flexural rigidity of warp knitted fabrics.

Large quantities of energy are required in distillation of light olefms such as ethylene used for polymer grade separations of close boiling mixtures. Since the ethylene/ethane separation is the more difficult separation in terms of energy and requirement, it also provides greater opportunity for altering the economics of the ethylene process. The purpose of this paper is to introduce an industrially viable; internally heat integrated distillation column (HIDiC) version of a state of art C2 splitter by using a heat pump assisted, stand-alone column. In this article, a methodology is proposed for the thermal integration of electrically driven heat pumping systems between intermediate stages in distillation column using the concept of Column Grand Composite Curve (CGCC). To accomplish this goal, Equation Oriented (EO) modular of Aspen plus is applied. This research differs to other's work in term of heat penalty that causes more utility load and hydraulic bottlenecking in a column. An objective function consisting of utility costs and product revenue is established to maximize the net profit obtained from this process. A sensitivity analysis is executed over different electricity and capital cost scenarios. Eventually, the most competing scenarios in term of total annual profit are determined.

In this research, the effect of organic carbon content of soil on bioavailability of phenanthrene contaminated soil was studied. Five different soil samples, with different total organic carbon content ranging from 0.5-13.3 (w/w) % were collected from different area. The samples were polluted with phenanthrene, and then the biodegradation of the phenanthrene in presence of pseudomonas species was evaluated. According to the results, 75- 95% of phenanthrene was degraded during 95 days in contaminated samples, in the presence of bacteria. In contrast with the preliminary results, the bioavailability of phenanthrene is complicated and it could result from various parameters. Further experiments were designed to compare the phenanthrene bioremediation under in situ and slurry reactor. The results reveal that the slurry reactor has the same degree of phenanthrene biodegradation in short period of time.

In this paper, Clinoptilolite, a natural zeolite from Semnan region, is used to synthesize a catalyst for methanol dehydration to DME. To produce such a catalyst and implement acid sites on the latter, the ionexchange process has been applied. In addition, to optimize the effective factors in the catalyst synthesis process, a L9 Taguchi experimental design has been used. In this design, the effects of four factors have been studied: Ion-exchange solution type (2 levels); Ion-exchange solution concentration; Calcination temperature and calcination time (the last three factors have been studied in 3 levels). The yield of catalyst (conversion * selectivity) has been chosen as the response. To study the effects of these factors on the response, the 9 samples have been tested using a fixed bed reactor. (at T= 350°C, P= 1 atm & WHSV= 4.78 hr-1). The results of the statistical design show that the optimized conditions are calcinations time 3 hours, 2N ammonium chloride, as the ion-exchange solution and calcination temperature at 500°C. The optimized catalyst was tested using a fixed bed reactor at 330° C atm pressure and WHSV= 13.8 hr-1. The results showed 98.1% conversion and 96.5% selectivity. In order to study the catalyst behavior under the industrial operation conditions, the sample was tested in a fixed bed reactor at 300° C 16 bar pressure and WHSV=52.5 hr-1, the results indicated 67.2% conversion and 99.74% selectivity.

In this research core spun yarns were produced by three spinning systems namely ring, solo and siro spinning system under the same initial conditions such as filament pre-tension (100 gram) and twist per meter (T.P.M = 415), and then their physical and mechanical properties including strength, elongation percentage, abrasion resistance, CV% and hairiness were investigated. Moreover, the effect of feed position of core filament on physical and mechanical properties of siro core spun yarns studied and the best position was determined.The results show that Solo core spun yarn has more strength than Ring and Siro core spun yarns; however, Siro core spun yarn shows better characteristics with respect to hairiness, abrasion resistance & CV percentage comparing to its Ring & Solo core spun yarns counterpart.

In the present work, at first, rotor spun yarns of 10Ne, 16Ne and 20Ne have been produced from card and draw-frame slivers separately. Then, for the comparison of yarn from two slivers, the evenness and tensile behavior of yarns have been tested.In this work, the parameters which have been investigated are variation in yarn mass (CVm%) , number of thick places and thin places, nep, elongation and tenacity.The results showed that producing rotor spun yarn is possible by feeding card sliver directly. In addition, according to the results the quality of yarn with the count of 10Ne was better than other investigated yarns produced by card sliver feeding material.