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Showing 4 results for Javidi


Volume 12, Issue 3 (10-2012)
Abstract

In recent years, many large ground motions occurred very close to modern cities and caused severe damage to buildings. Damage to modern engineering structures is beyond engineers’ expectation, because the structures are thought to have been designed according to proper ground motion-resistant design standards. In these buildings, although the distribution of strength for all stories of designed structures was considered uniform, but the distribution of overall damage of stories was non-uniform and considerable damage for some stories was observed. In this study, 8, 12 and 15-story dual steel moment-resisting frames with concrete shear wall were designed as a residential building that was located in seismic zone 4 (very high relative seismic risk region). These structures were designed with uniform strength ratio for all elements according to the modal response spectra analysis and static equivalent lateral seismic load pattern that were typically recommended by most building codes. Then six severe ground motions recorded in soil type III with magnitude greater than 6.2 on the Richter scale, without forward directivity, were selected. Finally, all structures subjected to these six severe ground motions and distribution of damage was examined by using nonlinear dynamic analysis. According to the results, despite uniform distribution of strength for all elements, element types and stories in each structure, the distribution of overall damage for element types (e.g. beams, columns and shear wall) and stories and the distribution of local damage for elements are non-uniform and among different stories, first and last stories have minimum overall damage and among different elements types, the damage of the beams is more than columns and shear wall and increasing the number of stories has not been effected on the distribution of damage of elements, and for 8, 12 and 15-story distribution of damage of elements is similar. Evaluation of distribution of damage on elements illustrate that the beams and columns near the shear wall have been damaged more than the beams and columns that are located far from the shear wall. On some stories, the beams and columns near the shear wall have been damaged considerably, but the beams and columns that are located far from the shear wall have been remained elastic. Also, these results conclude that the distribution of overall damage on stories and element types are not adequate for evaluation of seismic damage and the local damage of each element should be examined separately, because from distortion of the results caused by the temperature effect. As the complexity of equipment and speed of testing for the RCPT and RCMT tests are similar, the RCMT test can be recommended for more realistic appraisal of concrete. There was good correlation between the results of the RCMT and electrical resistance test which shows a good potential for utilization of the electrical resistivity methods for appraisal of chloride resistivity of concrete.

Volume 16, Issue 87 (5-2019)
Abstract

In this research, the effects of whey protein concentrate based edible coatings containing different concentrations of natamycin and lysozyme–xanthan gum conjugate were investigated. For this purpose, Escherichia coli O157:H7 (as an indicator for gram negative bacteria and also resistant to commercial pasteurization), Staphylococcus aureus (as an indicator of gram-positive bacteria), and Penicillium chrysogenum were inoculated to ultrafiltrated white cheese surface and the microbial properties of cheese samples were evaluated during 28 days storing. The results showed that all coated treatments significantly reduced the growth of Penicillium chrysogenum. Natamycin-containing coatings have been more effective in reducing the mold population than lysozyme-xanthan-containing coatings. Coated samples containing 600 ppm lysozyme-xanthan reduced E. coli O157: H7 growth 2.09 log compared to control samples. Also, the growth rates of Staphylococcus aureus were lower in all samples treated with lysozyme-xanthan than control sample. The lowest growth rate of Staphylococcus aureus was observed in the coated sample containing 600 ppm lysozyme-xanthan on 28th day, with a microbial population of 2.60 logarithms. Unlike other treatments, the growth rate of Staphylococcus aureus in the sample coated containing 600 ppm lysozyme-xanthan was descending over 28 days. The results of this study showed that whey protein based edible coating can be used as a carrier of natamycin and lysozyme-xanthan in optimal concentration, for increasing the microbial quality of UF cheese.

Volume 18, Issue 112 (May 2021)
Abstract

In this study, the effect of WPC, MPC, Milk powder, wheat fiber, and mixer of wheat and psyllium fiber at two levels (1 and 2%) on the physicochemical, quality properties of low-fat yogurt during 21-day storage time investigated. The results of this research showed that the addition of a mixer of wheat and psyllium fiber caused decreasing in pH and increasing in acidity. Samples contain MPC had the least Syneresis and the highest viscosity so that the difference among samples was significant. Samples contain WPC, had the most TSS. On the first day and 21st day, samples with WPC and milk powder had the most microbial growth, respectively. According to these results, the best effects on quality properties were included: decreasing Syneresis, increasing viscosity especially for MPC samples, and a good influence on microbial growth for all samples. Overall, using fibers and protein concentrate compounds can improve quality properties and has a good potential for application in varied food products.

Volume 25, Issue 3 (Fall 2021)
Abstract

According to the principle of Freedom of contract the parties to the contract can include their preferred condition in the contract. In this way the condition of the best effort to fulfill the obligations is one of the conditions that can be mentioned in the contract, according to which, the obligor will do his best to fulfill the obligation. Such a condition causes the obligor not to think only of relieving himself. Despite the frequent use of such a condition in US contracts, there is no consensus on its validity. In this legal system, Some lawyers do not accept the mentioned condition due to its generality and ambiguity and consider it invalid, and on the other hand, they consider it correct. Recently, in international documents such as Unidroit Principles of International Commercial Contracts and Principle of European Law Service Contract  the condition of the best effort has been recognized and declared valid. In Iranian law, this condition is explicitly accepted in some laws, such as insurance laws and medical law. This article, using a descriptive-analytical method, after explaining the concept of the best effort condition, examines the position of this condition in the legal systems of Iran and the United States, as well as some international legal documents.

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