فهرست مطالب mehdi jafarian

In urban management area, modeling and proposing new solving approaches to optimize different related transportation problems, is one of the most important and challengeable subject. In the literature, researchers have considered different problems related to public transportation and urban traffic, waste management, rescue and crisis, and even urban tourism in this context, and have discussed these works have caused decreasing costs, increasing rapidity and ease of transportation, decreasing pollution, and accelerating movement to build a sustainable city. This paper proposes, describes and models a new type of Orienteering Problem (OP) which has high level of compatibility with urban transportation problems, and in which the time horizon is not constant and changes depending on the events and conditions of visiting vertices. To solve this problem, a heuristic algorithm, based on greedy concepts is proposed and its performance has been investigated by 85 random samples.

Nowadays, due to the increasing rate of environmental complexities and the growing number of effective factors in making appropriate decisions, making decisions based on scientific principles has obtained a specific status among the top managers. Opting for the best consultancy firm, as one of the most important decisions the top managers would make for receiving consultancy services, has changed into a vital decision regarding the complications of the current business atmosphere and the effects of the quality of such services on the future sustenance of an economic enterprise. In this paper, in order to make a proper decision to opt for an appropriate consultant in devising strategic plans, a nine-step procedure is presented the most important advantages of which are the pre-qualification of the alternatives and the classification of decision-making criteria into general and specific groups. The proposed procedure has been investigated and analyzed utilizing the real data collected from Tehran Beautification Organization (TBO). The results show that the proposed procedure for selecting consultants for strategic plans in urban management is of high applicability and replicability.

Recently it is shown that Mycobacterium tuberculosis Beijing genotype are associated with drug resistance. Thus a simple and rapid method is required for identification and differentiation of Beijing family isolates. Therefore the aim of this study is to evaluate discriminatory power of different loci in both 12 MIRU-VNTR and 15 MIRU-VNTR Methods for Beijing genotype. In total 105 Mycobacterium tuberculosis strains were identified by spoligotyping, then genomic analysis was carried out by using 12 and 15 MIRU-VNTR methods. Allelic diversity for each locus was calculated using Hunter Gaston Discriminatory Index (HGI). With spoligotyping 20 out of 105 isolates (19.05%) belonged to the Beijing family. Investigating all strains with 12 and 15 MIRU-VNTR showed that 11 loci were highly discriminative (HGI≥0.6) and QUB26 had the highest discriminatory power (HGI=0.84). Number of repeats in QUB11b was specific for Beijing genotype, and only MIRU16 was highly discriminator for this genotype. QUB26, Mtub21, MIRU39, MIRU27, MIRU23 and MIRU26 were moderately discriminator (0.4≤HGI<0.6) and other loci were poorly discriminator for Beijing strains (HGI<0.4). 12 and 15 locus MIRU-VNTR are simple and rapid methods and suitable for differentiation of Beijing genotype from other MTB strains, however these two methods are not suitable for discriminating Beijing family among themselves. In overall discriminatory power of 15 locus MIRU-VNTR method was higher than 12 locus MIRU-VNTR.

Molecular epidemiology analyses are frequently used in determining epidemiology of tuberculosis. Recently, Mycobacterial Interspersed Repetitive Unit Variable Number Tandem Repeat (MIRU-VNTR) and Spoligotyping has become an important method, as it allows high-through put, discriminatory and reproducible analysis of clinical isolate. The purpose of this study is to compare techniques of “MIRU-VNTR” versus “MIRU-VNTR and Spoligotyping” together for study of genetic pattern of Mycobacterium tuberculosis (M. tuberculosis) strains. Sixty M. tuberculosis (MTB) isolates were selected (30 susceptible, 30 multi-drug resistant) for this study. Thereafter, the «MIRUVNTR and Spoligotyping» were performed to identify their genetic patterns. The frequency of unknown genetic pattern of MTB was compared using technique of “MIRU-VNTR” alone versus “MIRU-VNTR and Spoligotyping” together. The MIRU-VNTR allelic diversity at each of the loci was calculated by Hunter – Gaston Discriminatory Index (HGDI). Based on differentiation index of all strains 10, 16, 26, 31 and 40 loci were identified as the most distinctive (HGI ≥ 0. 6) and 2, 4, 20 and 24 as the weakest distinctive locus (HGI ≤ 0. 3). By using MIRU-VNTR technique 38% (n= 23) of isolates could not be typed, whereas by applying «MIRU-VNTR and Spoligotyping» togetheronly 15% (n= 9) of isolates remained unknown (p = 0. 004). For sensitive strains, the difference was significant (67% vs. 90%, p = 0. 028), but only marginally significant for drug resistant strains (57% vs. 80%, p = 0. 052). The discrimination power of 12-locus MIRU-VNTR and Spoligotyping was equal to that of MIRU-VNTR analysis. If appropriate loci are added to the standard MIRU analysis, MIRU-VNTR genotyping could be a valuable tool for strain typing and epidemiological research of M. tuberculosis. With this approach amore clear understanding about genetic pattern of MTB can be achieved.

Nowadays, MDR strains of mycobacterium tuberculosis are a serious problem in many countries which poses difficulties for TB control program. Since 1990s, spread of MDR TB cases in different parts of the world have been reported which is mainly because of incorrect use of TB drugs. One of the main causes of drug resistance occurring as a complication of human mistakes can be wrong classification and lack of monitoring of the patients during treatment and lack of supervision on the consumption of anti TB drugs. The purpose of this study was to investigate genetic diversity of M.tuberculosis strains isolated from patients by means of MIRU-VNTR technique. In this study 96 mycobacterium tuberculosis strains were isolated from the patients with pulmonary tuberculosis and drug sensitivity tests was performed by MIRU-VNTR technique. Genetic diversity of the strains based on MIRU-VNTR loci was estimated. Allelic difference of each loci was determined by means of statistical HGDI formula. Genetic pattern of sensitive strains showed that these strains belong to families of Dehli/CAS, Haarlem, LAM, H37RV and Caprae. Most drug resistant strains had genetic pattern of Haarlem and LAM families. Loci allelic differences between sensitive and resistant strains were not significant. Based on differentiation index of all strains, 10, 16, 26, 31 and 40 loci had the most allelic differences (HGI ≥ 0.6) and 2, 4, 20, 24 and 27 loci had the least differences (HGI ≤ 0.3). The results showed that most genetic diversity of sensitive and resistant strains belonged to Haarlem and Dhli/CAS families and MIRU-VNTR technique used in this study for determination of genetic diversity of mycobacterium strains is a rapid, accurate and cheap method which can be used easily in the populations with high frequency of TB.

Surface roughness is one of the most important parameters that plays very critical role in determining the quality of engineering components. A good surface quality resulting in improve of fatigue strength, corrosion and wear resistance of the workpiece. On the other hand, increasing cutting speed and decreasing time of machining are desirable for manufacturers in order to reduce costs and increase rate of production. According to importance of above subjects, having high surface with low cost is required to have proper understanding of cutting parameters of WEDM. In this study, the effect of parameters such as Power, Time-off pulse, Open circuit voltage and Servo voltage on Tungsten carbide is investigated