علی مهاجری

Fischer-Tropsch synthesis provides an alternative route for the production of clean transportation fuels and high molecular weight hydrocarbons via catalyzed CO hydrogenation. In this paper, three nanocatalysts including iron, copper, potassium, and lanthanium were prepared using a microemulsion method. The composition of the final catalysts, in terms of the atomic ratio of the elements, was selected as 100Fe/4Cu/2K, 100Fe/4Cu/2La, and 100Fe/4Cu/1K/1La. XRD, BET, TEM, and TPR techniques were employed for the investigation of phase, structure, and morphology properties and the reduction in temperature. Fischer-Tropsch synthesis reaction was performed in a fixed bed reactor at a pressure of 18 atm, a temperature of 290 °C, an H2/CO ratio of 1, and a GHSV equal to 3 NL.h-1.gCat-1. The results show that the reaction activities of Fischer-Tropsch synthesis and water-gas shift are higher in the case of using two promoters compared to when only one promoter is employed. Methane selectivity dropped to about 10.8%, while CO conversion increased to around 86.9%, when two promoters were used.

This investigation was carried out to study the qualitative and quantitative performance of two varieties of forage maize under conventional, integrated and in conversion to organic production systems in summer of 2010 in Pishavar (in Varamin). The experimental design was split-plot, based on Randomized Complete Block Design (RCBD) with three replications. Treatments consisted of production systems (conventional, integrated and in conversion to organic) located in the main plots and two varieties (single cross 704 and single cross 260) arranged in the sub-plot. In conventional production system only chemical inputs were used. For integrated production system, chemical, organic and biologic nutrients were used together. But for organic production system, only biological organic inputs were applied. Results showed that maximum values ​​for dry forage yield, wet forage yield were respectively related to the integrated production systems and the highest plant height obtained from conventional production systems, respectively. The results showed that single cross 704 have maximum values for all measured traits than single cross 260, except for nitrogen content in the leaves.

In this paper, three nanocatalysts of iron, copper, and strontium were prepared by a microemulsion method. The composition of the final catalysts, in terms of the atomic ratios, are Fe, 100 Fe/3 Cu, 100 Fe/3 Cu/2 Sr. XRD, BET, TEM, and TPR techniques were utilized for the investigation of the phase, structure, and morphology properties of the synthesized catalysts. The performances of the catalysts were tested in a fixed-bed stainless steel reactor. Nanoiron catalyst contained promoter material improved the Fischer-Tropsch synthesis (FTS) and water-gas shift (WGS) activities, while decreased methane selectivity to 7.44%; CO conversion and chain growth probability were also increased to 63.3% and 0.66 respectively.

In this paper, some samples of supported carbon membranes are prepared with phenolic resin as a precursor. The effects of coating conditions including solvent type, resin concentration, and coating method on the preparation of a defect-free resin layer on the support surface are investigated. This layer is faced to carbonization operation to be converted to the carbon layer. To study the effect of support, two different supports with different materials and porosity are used. The results show that only resin concentration affects the preparation of the defect-free layer. A high concentration of resin can produce a complete layer on the surface of the support. But this layer is destroyed during carbonization and some cracks appear on the surface of the membrane due to the high thickness of resin layer. Similar experiments with supports having pores with smaller diameters show similar results. By repeating the coating-carbonization cycle, producing the complete resin layer is possible; but, this layer is also destroyed during carbonization and the produced membrane shows a little selectivity for gas separation.

Provisional measures such as injunction, securing evidence, freezing injunction and suspension of releas are among the most important legal measures adopted in fair and equitable proceedings related to the intellectual property rights, which have been considered in the third chapter of the World Trade Organization Agreement on Trade-Related Aspects of Intellectual Property Rights (TRIPs). In the Iranian legal system, this subject is more or less given attention. This study, however, reveals that the new law not only did not put us in a better situation in comparison with the previous law, but also created imperfections and ambiguities that didn’t exist in the previous law. The executive regulations of the new law, sporadically and in a disorderly way have adopted some of the provisions of the previous regulations as part of efforts to remove the existing imperfections and flaws. Actually, it has exceeded the legal limits in some cases. In this research, the author draws a comparison between the new law and the TRIPs Agreement while challenging the new law and its executive regulations. Finally, it sets forth some proposals for amending the existing law.

In this paper، CO2 adsorption isotherms at 273 K are measured on five commercial carbonaceous adsorbents using volumetric method and their pore size distributions are determined and compared using DA، DS and HK models. The results show that although the average pore diameter obtained from these models are almost the same، these models show different pore size distributions. Then obtained results from HRTEM images of one of samples and these model results are compared. The results also show that the average error for HK، DA and DS models are 2. 04، 2. 73 and 1. 42، respectively. Thus، DS model is introduced as the best model for determination of pore size distribution، and DA model gets the third rank.

Endpoint detection, which means distinguishing speech and non-speech segments, is considered as one of the key preprocessing operations in automatic speech recognition (ASR) systems. Usually the energy of speech signal and Zero Crossing Rate (ZCR), are used to locate the beginning and ending for an utterance. Both of these methods have been shown to be effective for endpoint detection. However, especially in a high noise environment they fail. In this paper, we integrate the modified Teager approach with the Energy-Entropy Features. In our new algorithm, the Teager Energy is used to determine crude endpoints, and the Energy-Entropy Features are used to make the final decision. The advantage of this method is that there is no need to estimate the background noise. Therefore, it is very helpful for environments when the beginning or ending noise is very strong or there is not enough “silence” at the beginning or at the end of the utterance. Experimental results on Farsi speech show that the accuracy of this algorithm is quite satisfactory and acceptable for speech endpoints detection.