Analysis and modeling of rail maintenance costs

Railroad maintenance engineering plays an important role on availability of roads and reducing the cost of railroad incidents. Rail is of the most important parts of railroad industry, which needs regular maintenance since it covers a significant part of total maintenance cost. Any attempt on optimizing total cost of maintenance could substantially reduce the cost of railroad system and it can reduce total cost of the industry. The paper presents a new method to estimate the cost of rail failure using different cost components such as cost of inspection and cost of risk associated with possible accidents. The proposed model of this paper is used for a real-world case study of railroad transportation of Tehran region and the results have been analyzed

Comparative –Analytical Study of Economic Productivity of Water between Smallholding and Rural Production Cooperative Utilization System

In recent years, farming section of South Khorasan Province faces different limitations such as increasing shortage of water resources and continuous reduction of weather showers. Considering consecutive droughts and water crisis in agricultural plain of the province, it is necessary to use water resources optimally and increase productivity of water shortage input. Comparison of water productivity among the available utilization systems in agricultural section of the province can cause recognition of suitable and efficient utilization system for optimal use of water shortage input and increase water productivity in production of crops. In the present research, different indices of water productivity for production of crops in two small holding utilization system and Rural Production Cooperative in Khosef County have been calculated and compared. The required data have been collected with a sample of 247 farmers and with two-staged cluster sampling and with questionnaire. To calculate and compare water productivity, Benefit Per Drop, Crop Per Drop and Net Benefit Per Drop indices have been used. Results showed that the said indices were different for similar products in two utilization systems and in most crops, the said indices in rural production cooperative system were higher than small holding system. Therefore, gathering of smallholder’s farmers as rural production cooperative can lead to more desirable utilization of water resources and reduction of drought effects and water crisis

Energy Efficiency Analysis and Modeling the Relationship between Energy Inputs and Wheat Yield in Iran

W heat is the dominant cereal crop constituting the first staple food in Iran. This paper studies the energy consumption patterns and the relationship between energy inputs and yield for Wheat production in Iranian agriculture during the period 1986 -2008. The results indicated that total energy inputs in irrigated and dryland wheat production increased from 29.01 and 9.81 GJ ha -1 in 1986 to 44.67 and 12.35 GJ ha -1 in 2008, respectively. Similarly, total output energy rose from 28.87 and 10.43 GJ ha -1 in 1986 to 58.53 and 15.77 GJ ha -1 in 2008, in the same period. Energy efficiency indicators, inputoutput ratio, energy productivity, and net energy have improved over the examined period. The results also revealed that nonrenewable, direct, and indirect energy forms had a positive impact on the output level. Moreover, the regression results showed the significant effect of irrigation water and seed energies in irrigated wheat and human labor and fertilizer in dryland wheat on crop yield. Results of this study indicated that improvement of fertilizer efficiency and reduction of fuel consumption by modifying tillage, harvest method, and other agronomic operations can significantly affect the energy efficiency of wheat production in Iran. Abstract International Journal of Agricultural Management and Development (IJAMAD

Analysis of an RFID Authentication Protocol in Accordance with EPC Standards

In the past few years, the design of RFID authentication protocols in accordance with the EPC Class-1 Generation-2 (EPC C1 G2) standards, has been one of the most important challenges in the information security domain. Although RFID systems provide user-friendly services for end-users, they can make security and privacy concerns for them. In this paper we analyze the security of an RFID mutual authentication protocol which is based on EPC Class-1 Generation-2 standard and proposed in 2013. The designers of protocol claimed that their protocol is secure against different security attacks and provides user privacy. In this paper, we show that unlike their claims, their protocol is not secure against most of the security attacks such as replay attack, the tag’s ID exposure, and the spoofing attacks. As a result, their protocol cannot provide security of RFID users in different authentication applications. Finally, in order to prevent the aforementioned attacks and overcome all the existing weaknesses, we apply a modification in the updating procedure of the protocol and propose a strengthened version of it

Energy Efficiency Analysis and Modeling the Relationship between Energy Inputs and Wheat Yield in Iran

Wheat is the dominant cereal crop constituting the first staple food in Iran. This paper studies the energy consumption patterns and the relationship between energy inputs and yield for Wheat production in Iranian agriculture during the period 1986 – 2008. The results indicated that total energy inputs in irrigated and dryland wheat production increased from 29.01 and 9.81 GJ ha-1 in 1986 to 44.67 and 12.35 GJ ha-1 in 2008, respectively. Similarly, total output energy rose from 28.87 and 10.43 GJ ha-1 in 1986 to 58.53 and 15.77 GJ ha-1 in 2008, in the same period. Energy efficiency indicators, input– output ratio, energy productivity, and net energy have improved over the examined period. The results also revealed that nonrenewable, direct, and indirect energy forms had a positive impact on the output level. Moreover, the regression results showed the significant effect of irrigation water and seed energies in irrigated wheat and human labor and fertilizer in dryland wheat on crop yield. Results of this study indicated that improvement of fertilizer efficiency and reduction of fuel consumption by modifying tillage, harvest method, and other agronomic operations can significantly affect the energy efficiency of wheat production in Iran

Removal of O-Nitrophenol from Petrochemical Wastewater: Comparison Between SBR and MSBR Biological Reactors

The discharge of wastewater from various industries such as petroleum and petrochemical, pollute water resources. The presence of these pollutants in water resources will cause disorders in the ecosystem and it has various risks to human health. The effluent usually contains organic matter, including phenol and its derivatives. In this study, three different types of reactors were used in the activated sludge process to study the biological removal of o-nitrophenol from the petrochemical industrial effluent. These reactors include Continuous Moving-Bed Sequencing Batch Reactor, Moving-Bed Sequencing Batch Reactor and conventional sequencing batch reactor. For this purpose, the operational indicators of each reactor were investigated and optimized. For MSBR, active sludge volume ratio (30%), aeration flowrate (18 L/min), operation time (4h), pH (7), filler to reactor volume ratio (4.7 %) and SVI (89 ml/g) were considered. Also, For C-MSBR indicators such as initial volumetric flowrate (20 ml/min), aeration flowrate (12 L/min), filler to reactor volume ratio (5.8 %) and SVI (98 ml/g) were optimized. As SBR is structurally similar to the other reactors, only initial volumetric flowrate was considered (40 ml/min) and based on the results, this reactor has better SVI (88 ml/g) than the other two reactors. Finally, based on the optimized parameters, percentage removal of ortho nitrophenol from a synthesized effluent, analogous to Karoon Petrochemical company effluent, was investigated by C-MSBR. In addition to o-nitrophenol, other chemicals such as Toluene and Benzene were also present. The results show the indicators including ortho nitrophenol percentage removal (84.7%), Chemical Oxidation Demand (COD) (94%), Biochemical Oxidation Demand (94.8%), BOD5/COD (0.57) and SVI (74.45 ml/g) comply with environmental standards and the treated effluent can be used in irrigation and agriculture by addition of one more processing step

Opium use and risk of bladder cancer : A multi-centre case-referent study in Iran

Background: Bladder cancer (BC) is the 10th most common type of cancer worldwide and the fourth most common type of cancer in Iran. Opium use is considered as one of the risk factors for BC. We aim to assess the association between various parameters of opium use, which in Iran is mainly ingested or smoked in various forms, and the risk of BC. Method: In this multi-centre case-referent study in Iran, 717 BC cases and 3477 referents were recruited to the study from May 2017 until July 2020. Detailed histories of opium use (duration, amount, frequency) and potential confounders were collected by trained interviewers. Multivariable unconditional logistic regression models were used to measure adjusted odds ratio (OR) and 95% confidence intervals (CI). The ORs were adjusted for age, gender, place of residence and pack-years of cigarette smoking. Results: Regular opium consumption was associated with an increased risk of BC (OR 3.5, 95% CI: 2.8, 4.3) compared with subjects who never used opium. Compared with continuous users, the risk decreased to one-Third for those who stopped opium more than 10 years ago. The adjusted OR for those who used both crude opium (teriak) and opium juice was 7.4 (95% CI: 4.1, 13.3). There was a joint effect of opium and tobacco (OR for users of both opium and tobacco 7.7, 95% CI: 6.0, 9.7). Conclusions: Regular opium use is associated with an approximately 4-fold risk for BC. The OR decreases along with the increasing time since stopping opium use.publishedVersionPeer reviewe

Genomic insights into the 2016-2017 cholera epidemic in Yemen.

Yemen is currently experiencing, to our knowledge, the largest cholera epidemic in recent history. The first cases were declared in September 2016, and over 1.1 million cases and 2,300 deaths have since been reported1. Here we investigate the phylogenetic relationships, pathogenesis and determinants of antimicrobial resistance by sequencing the genomes of Vibrio cholerae isolates from the epidemic in Yemen and recent isolates from neighbouring regions. These 116 genomic sequences were placed within the phylogenetic context of a global collection of 1,087 isolates of the seventh pandemic V. cholerae serogroups O1 and O139 biotype El Tor2-4. We show that the isolates from Yemen that were collected during the two epidemiological waves of the epidemic1-the first between 28 September 2016 and 23 April 2017 (25,839 suspected cases) and the second beginning on 24 April 2017 (more than 1 million suspected cases)-are V. cholerae serotype Ogawa isolates from a single sublineage of the seventh pandemic V. cholerae O1 El Tor (7PET) lineage. Using genomic approaches, we link the epidemic in Yemen to global radiations of pandemic V. cholerae and show that this sublineage originated from South Asia and that it caused outbreaks in East Africa before appearing in Yemen. Furthermore, we show that the isolates from Yemen are susceptible to several antibiotics that are commonly used to treat cholera and to polymyxin B, resistance to which is used as a marker of the El Tor biotype

Determining Influential Users in Social Networks (The Case of: Word of Mouth on Digikala Company Instagram Page)

The emergence of social networks is one of the most influential phenomena of the 21st century. Social networking cyberspace creates a broad area of information and a variety of semantic representations. Social networks connect different people with different interests and ideas together. Due to the huge amount of intellectual potential and human thought in social networks, a great number of businessmen or retailors and commerce managers are attracted to such networks. The main objective of this study is to identify the most effective members in the cycle of content propagation on social networks and to propose solutions to improve the propagation of advertising and marketing on social networks to help business owners and managers. The case study of this research is "DigiKala" Instagram social network. At first, using the NodeXL software, the general content of DigiKala Instagram pages were collected. In the next step, applying clustering methods we found effective people using AlSuwaidan framework. Then, the collected data were processed using Matlab software. Finally, the obtained results were evaluated and based on the tests, 9 of the most influential people in accordance with the highest coefficient in publishing content on the social network were introduced