Search

One of the most important environmental problems in recent years in the Middle East including Iran is the dust storm events. The main goal of this research was to conduct statistical analyses to identify the dusty days with visibility to less than 1 km. This study also dealt with the recognition of sources of this phenomenon and the route for dusts to enter Isfahan Province. In this study, data were collected for a 20-year period (1994–2013) including daily dust data at the ground stations, brightness temperature at wavelengths of 11 μm and 12 μm, and GDAS data for tracking the dust particle route in HYSPLIT software. Naein and Airport stations with frequencies of 920 and 919 days of dust (respectively) were identified as two critical centers of dust in Isfahan province. The spring season had the highest number of days with dust. Also, the highest and lowest frequencies of this event were observed in April–May–June and December–January, respectively. The border area between Iraq and Syria, west and southwest of Iraq, was the main source of the dust transported to Isfahan. Thermodynamic conditions of atmosphere using the Skew-T diagrams were stable during the dust events in the study area.

Extreme ground behaviour in high-stress rock masses such as rockburst prone and squeezing ground conditions are encountered in a range of underground projects both in civil and mining applications. The occurrence of such ground behaviour types are difficult to predict and special design and construction measures must be taken to control them. Determining the most appropriate support system in such grounds is one of the major challenges for ground control engineers because there are many contributing factors to be considered, such as the rock mass parameters, the stress condition, the type and performance of the support systems, the condition of major geological structures and the size and geometry of the underground excavation. The main characteristics and support requirements of rockburst-prone and squeezing ground conditions are herein critically reviewed and characteristics of support functions are discussed. Different types of energy-absorbing rockbolts and other support elements applicable for ground support in burst-prone and squeezing grounds are introduced. Important differences in the choice and economics of ground support strategies in high-stress ground conditions between civil tunnels and mining excavations are discussed. Ground support benchmarking data and mitigation measures for mines and civil tunnels in burst-prone, squeezing and heavily swelling grounds conditions are briefly presented by some examples in practice.

The cell membrane of rooster sperm is sensitive to cold due to the high content of polyunsaturated fatty acids, which are very susceptible to lipid peroxidation. The present study was conducted to determine the effect of different concentrations of the mitochondrial-targeting antioxidant "MitoQ" on sperm quality and fertility potential of chilled semen in roosters. Semen samples were collected from 10 roosters, diluted in Lake extender, assigned into 5 groups according to MitoQ concentrations (0, 1, 10, 100 and 1000 nM MitoQ) and stored at 5

Supplementation of sperm cooling medium with helpful additives is a reasonable method to conserve sperm fertility potential during cooling storage process. This study was aimed to determine the effect of sperm cooling medium supplementation with Zinc and Zinc oxide nanoparticles (NZn and NZnO) on rooster semen quality and fertility efficiency during storage periods. Semen samples were diluted in the Lake medium and assigned into five equal aliquots. The first was Control group and the other groups received 50 μg/ml NZn, 50 μg/ml NZnO, 100 μg/ml NZn and 100 μg/ml NZnO. Then, the samples were cooled at 5 °C and conserved up to 45 h. Total motility, progressive motility, mitochondrial activity, viability, membrane integrity and lipid peroxidation of samples were analyzed during 0, 22 and 45 h post-cooling. Artificial insemination was also performed using 22- hrs cooled semen. No difference was found among groups during quality evaluations at 0 h storage. Extender supplementation with 100 μg/ml NZn and NZnO presented higher (P ≤ 0.05) total motility, progressive motility, mitochondrial activity, viability, membrane integrity and lower lipid peroxidation compared to other groups during 22 and 45 h cooling storage. Fertility rate of 22-h cooled-stored semen samples was higher (P ≤ 0.05) in groups contained 100 μg/ml NZn and NZnO compared to the Control group. In conclusion, addition of 100 μg/ml NZn and NZnO to the sperm storage medium could be introduced as an effective method to preserve rooster semen quality during cooling storage period.

Supersulfated cements (SSC) are normally produced from granulated blast-furnace slags having high-alumina content. However, such slags are not produced in North America. In this study, SSC mixtures were produced using two different slags, one high in alumina content (13%) and the other low in alumina content (7%). The purpose of this study was to investigate the differences in hydration mechanisms of SSC produced with the two types of slag. The low-alumina slag SSC mixtures showed a lower degree of slag hydration and quantities of hydration products formed (C–S–H and ettringite), ultimately resulting in higher porosity and poor mechanical performance of the SSC mixtures compared to high-alumina slag mixtures. A better mechanical performance of SSC mixtures made with low-alumina slag may be achieved by increasing its rate of glass slag dissolution.

The present study aims to evaluate the performance of daily and monthly precipitation data relative to GPM-IMERG, TRMM_3B42 and PERSIANN satellite-based precipitation estimations against historical data for the period 2014–2017 as observed at 70 synoptic stations distributed over Iran. The coefficient of determination (R-squared), root mean square error and the Nash–Sutcliffe model efficiency coefficient were used to evaluate the performance of the used data sets against observed precipitation records at the considered stations. The statistics showed that the considered data sets are generally less successful in estimating daily precipitation at nationwide as the estimation errors were found high at almost all the studied stations. The errors of daily precipitation estimation of GPM-IMERG, TRMM_3B42 and PERSIANN-CDR data sets showed that although there is a considerable similarity between the estimated precipitation by the three data sets, especially between the TRMM_3B42 and GPM-IMERG, the accuracy of GPM-IMERG daily precipitation over Iran is higher than that of TRMM_3B42 and PERSIANN-CDR. The highest R2 value for GPM-IMERG, TRMM_3B42 and PERSIANN-CDR remotely sensed daily precipitation is equal to 0.6, 0.46, and 0.37, respectively. Similarly, on the monthly time scale, the GPM-IMERG, with an average R2 value of 0.83 over the country, performs better than the other two data sets. The TRMM_3B43 with mean nationwide R2 = 0.80 also showed comparative performance with GPM-IMERG, but the PERSIANN-CDR data set with an average R2 value of 0.4 over the stations is not as accurate as the GPM-IMERG and TRMM_3B43.

Rockbolt is widely employed all over the world as an effective ground reinforcement element in order to secure the underground workplaces. Ordinary encapsulated rebar or rebar rockbolt is most popular and commonly used as reinforcement in a ground support system because of its accessibility, cost effectiveness and easy practicability. Reinforcement elements in a seismic condition such as rock burst have to dissipate the energy release of the dynamic impact via their deformation and ultimate load capacity, knowing that the former is more important. In other words, achieving early stiff behaviour along with large deformation capacity in rockbolts are the goals for new development in rock reinforcement. Yielding rockbolts are expensive while some of them have large deformation capability with low ultimate load capacity. In this paper, modifications were made on encapsulation of rebar rockbolts to utilise it effectively as a yielding reinforcement in seismic conditions. Applying a sufficient decoupled length in the shank of rebar rockbolts which industry has regularly been using to control the bulking of the stress fractured ground, improves the deformation capacity of the bolt. Additionally, leaving a collar bonding underneath of the bearing pad and plate removes the weaknesses of the head anchorage of rockbolt. Therefore the dynamic performance of the bolt is improved by these easily applicable modifications. The behaviour and performance of encapsulated rockbolts have been discussed first, then the effects of modifications are illustrated. The proposed modification of the rebars is not only cost effective but also easy to apply in the field and improves the performance of reinforcements in seismic prone zones. Keywords: Rockbolt, Tunnel support, Collar bonding, Seismic rock support, Tunnelling

Underground mining is going to be deeper gradually because near surface resources are going to be depleted. Therefore, risk of seismic events in underground mines is escalating. Additionally, existence of the large ratio of horizontal to vertical stress, could be a potential reason for high-stress condition and occurrence of dynamic activities. Depending on various parameters such as the level of induced stress, rock properties, etc., ground demand changes and it is difficult to estimate. On the other hand, under seismic condition, energy dissipation and deformation capacity of supports is the most important factors, however, rock support performance factors in dynamic conditions are still under investigation. Expanding the knowledge of reinforcement behaviour and capacity, specifically that of the rockbolt as a primary element in seismic conditions, would help to develop a suitable, safe and economic support design. This paper contains various methods to estimate ground demand including the intact rock properties approach, failure thickness and ejection velocity estimation, and rockburst damage potential method. It also covers measurement methods of rockbolts energy dissipation capacities such as drop test, blasting simulating, back calculation and momentum transfer measurement methods. A large-scale dynamic test rig is also explained. Based on the findings, a table and a graph to show the applicable range of each type of rockbolts were presented. Suitable rockbolt types for various ground energy demand and deformation capacity range were categorised in the table and the graph. The presented support selection method facilitates the selection of a suitable reinforcement system at the preliminary stages of design and guides the designer to adjust the support reinforcement system based on observed ground and support reaction. Keywords: High-stress tunnels, Support system, Ground demand, Reinforcement capacity, Rockbolt

Alzheimer's disease (AD) is a multifactorial disease. In addition to the precipitating of two proteins betaamyloid peptide and neurofebrillary tangles, which are the main mechanisms involved in the pathogenesis ofAD, other factors such as inflammatory mechanisms and changes in lysosomal enzymes play an important part in the pathogenesis of this disease. Increased and decreased lysosomal proteases, such as cathepsin, can lead to functional impairment and gradual death of neurons. The aim of this review was to investigate the role of cathepsins in the pathogenesis of AD. To conduct this review, relevant articles published between 2000 and 2016, and indexed in reliable databases including PubMed, Google Scholar, Scopus and Web of Science were retrieved. After reviewing the articles, 30 articles that directly addressed the subject of this review were included in final analysis. Cathepsins exacerbate intracellular conditions in neurons, by processing beta-amyloid precursor protein and converting it into amyloid beta. They also play a protective role against AD and fight it by catalyzing the decomposition of beta-amyloids and converting them into the cut out forms of the carboxyl C-terminus. In addition, the 24 kDa fragment resulting from the effect of cathepsin D on apolipoprotein E (ApoE) is the second binding to the receptor in the ApoE. This fragment may also be the cause of the pathogenicity of Apo E in AD. Identifying and explaining the mechanisms involved in the pathogenesis of AD can play a significant role in the prevention and treatment of this disease. Since cathepsins play a pivotal role in the decomposition of beta-amyloid and reduction of the risk of AD, further studies can be considered an effective approach to study AD.Journal of Medical and Biomedical Sciences (2018) 7(1), 1 - 10

The current study was conducted to evaluate the effect of dietary fish oil on the semen quality and fertility potential of Zandi rams. For this purpose, a total of 15 Iranian Zandi rams were randomly assigned into three equal groups. The first group was a negative control and were fed without oil supplement. The second group was a positive control, and their diet contained palm oil, and the last group had a diet containing fish oil. All the diets were isocaloric and isonitrogenous. The rams were fed for 70 days, and the semen smaples were collected every 10 days. In experiment I, the evaluated parameters included semen volume, sperm concentration, motility, membrane integrity, and viability. In experiment II, 210 Iranian Zandi rams received CIDR for 12 days and 400 IU of equine chorionic gonadotropin at the time of CIDR removal. Then, they were assigned into three equal groups and artificially inseminated with semen samples. According to the obtained results, the supplementation of ram diet with fish oil as a source of omega-3 fatty acids improved the semen volume, sperm concentration, total motility, progressive motility, viability, membrane integrity, pregnancy rate, parturition rate, and lambing rate of the rams (P≤0.05). In conclusion, fish oil as a dietary supplement for rams could be an effective strategy to improve the semen quality of rams for artificial insemination and other goals.

In this paper, the growth of semi elliptical crack in the walls of thick walled cylindrical pressure vessels has been investigated. Considering the importance of the crack growth problem in cylindrical pressure vessels provides a numerical and experimental 3D model for the growth of fatigue crack and estimating the fatigue life of pressure vessels. Because of available geometric geometric and physical parameters, it can be predicted the problem of the fatigue life of these pressure vessels more precisely in comparison with existing standard tests which are experimental and numerical. A most common specimen of thick walled tanks, steel, is analyzed for conducting experimental tests. The mechanical properties and fatigue behavior of A516 steel have been determined experimentally. For estimating the crack growth and calculation of fatigue life, boundary element method and linear fracture mechanics equations have been used. Finally, the experimental results for fatigue crack growth were compared with numerical method, which yielded acceptable results. The overall results show a good agreement between the experimental data and the numerical results.

In this paper, fabrication of Al7075-SiC nanocomposite using dynamic compaction is investigated. Evaluation of material tensile characteristics are often destructive and costly and impossible for small samples. Therefore, instrumented indentation tests can be employed to obtain the tensile stress-strain curve of the material. In this investigation, the tensile stress-strain curve of Al7075-SiC nanocomposite is obtained using combination of spherical indentation test, finite element (FE) simulation, and neural networks. To fabricate the Al7075/SiC nanocomposite samples, Al7075 micron-sized powder and SiC nano particles were mixed to obtain Al7075-5 vol% SiC, and Al7075-10 vol% SiC and the mixtures were mechanically milled. The mixtures were then consolidated under impact loading by a single-stage gas gun. The compaction was performed at 573 K temperature and a maximum relative density of 97.5% was obtained. The load-penetration curve for each nanocomposite sample was obtained using spherical indentation test on the compacted samples. The corresponding numerical curve for each sample was also obtained by finite element simulation of the indentation process. Finally, using the experimental and the FE results, the constants of Hollomon’s material model were determined using artificial neural networks (ANN). The results indicated that SiC nano-particles reinforcement of Al7075 increased the tensile strength of the nanocomposite by around 300%.

Supersulfated cement (SSC) is potentially an environmentally attractive alternative to portland cement for use in concrete as it is mainly composed of industrial by-product granulated iron blast-furnace slag and calcium sulfate, with only a small amount of alkali activator. The low-alumina content (

The main goal of this research is the experimental and numerical study on the fatigue function and failure of the crankshaft of diesel engine of a heavy truck. To do this, a crankshaft of the diesel engine of a heavy truck that has gone under failure after traveling 955000 km, has been used. To examine the sources of this failure, several experimental studies have been carried out including chemical composition, the strength of the material, determining the hardness and the microstructure of the material. Besides, using an elastic–plastic three dimensional finite element method (FEM) model, the location of the maximum stress in the crankshaft was determined using the ‘‘complete crankshaft model’’ and ‘‘one crank model’’. Using the results of stress analysis, was a basis for the three-dimensional crack growth model and fatigue life estimation to determine the stress intensity factor and fatigue life considering the related parameters and boundary conditions method. At the final stage, using the results gotten from the given model for the fatigue crack growth, comparing it with experimental results, and examining the whole process, it was concluded that the scratches in crankpin region, was the main reason for the fatigue failure got from bending-torsional load-combination.

In this paper we will present a quantization method for SPP (Surface Plasmon Polariton) based on Green's tensor method, which is applied usually for quantization of EM-field in various dielectric media. This method will be applied for a semi-infinite structure, which contains metal and dielectric regions with one interface. Moreover, by introducing the quantized SPP, we will investigate the SPP propagation in the attenuating and amplifying systems. We will also consider two modes of SPP, i.e., coherent and squeezed states, and finally compare the propagation of these modes in the amplifying media.

Depression has a multifactorial aetiology and is one of the most common neurological and psychiatric disorders that are associated with imbalance in certain inhibitory and excitatory neurotransmitters and impairment of the brain-derived neurotrophic factor (BDNF). This review study was conducted to investigate the effect of BDNF and neuromediators on the development and severity of depression. To conduct this systematic review, relevant publications that were published between 2000 and 2016 and were indexed in the PubMed , Google Scholar , Scopus and Web of Science databases were retrieved using the depression , serum markers , neurotransmitters , serotonin , BDNF , dopamine , glutamate and gamma amino-butyric acid search terms. A total of 89 articles were included in final analysis. Depression is associated with imbalance of certain neurotransmitters such as serotonin, dopamine, norepinephrine, melatonin and glutamate in the central nervous system and impairment of BDNF. Taken together, there is a significant relationship between depression and neuromediators, and the decrease and increase in these mediators plays a significant role in depression. Studies have also confirmed that the antidepressant effect of drugs and medicinal plants is essentially related to the serotonergic pathway, especially the 5-HT1A receptor, and drugs and medicinal herbs are likely to exert their antidepressant activity through altering dopaminergic and serotonergic systems. Journal of Medical and Biomedical Sciences (2017) 6(3), 30 - 42

This study aims to analyze the rolling contact fatigue influenced by residual stresses caused by the contact of the wheel and rail and its manufacturing process. For this purpose, a rail available in Iran railway is used with an exact profile geometry. The location of maximum stress caused by the contact of wheel/rail for rail profiles can be calculated by three-dimensional elastic-plastic finite element model. Then, in order to estimate the stress distribution caused by rail manufacturing process, a thermal analysis with finite element method will be performed. Afterwards, the results of performed stress analysis will be used as input for three-dimensional crack growth and rail fatigue life estimation model to calculate the stress intensity factors and fatigue life according to the set of related parameters with boundary element method. Finally, three-dimensional finite element analysis results obtained show good agreement with those achieved in field measurements.

The Siah Bisheh pumped storage powerhouse cavern with complex geometry, changeable geological formations and diverse geotechnical properties of rocks, is under construction on the Chalus River 125 km north of Tehran, Iran. The powerhouse cavern was located near the downstream (d/s) dam reservoir and its crown was more than 30 meters lower than the downstream (d/s) dam maximum lake level. After impounding of the d/s dam, the powerhouse region would be located under saturated conditions. Therefore long term stability assessment of the powerhouse cavern under saturated conditions was unavoidable. In this study displacement based direct back analysis using variable staggered grid optimization algorithm was applied and calibrated geomechanical properties of rocks, stress ratio and joints parameters were identified. The time dependent behavior of rock was tested at the laboratory and the creep test results were considered in the practical design. Numerical modeling results were in good agreement with measured displacements of extensometers which confirmed the numerical modeling accuracy and back analysis results. Then ordinary analysis of the powerhouse cavern under natural conditions using back analysis results were carried out. Results of the analysis showed that the powerhouse cavern was stable under natural conditions and existing support system had suitable efficiency and could effectively control displacements. Finally, the powerhouse cavern long term stability under saturated conditions was analyzed. Results of analysis showed that after d/s dam impounding, pore water pressure and uplift pressure in discontinuities around the powerhouse cavern would arise so the powerhouse cavern tended to have local failure around the region 2nd and 3rd instrumentation arrays in the middle of the powerhouse cavern. To obtain powerhouse long term stability, it was recommended to construct a cutoff curtain grouting around powerhouse cavern.

This paper discusses the evaluation of secondary and tertiary oil recovery in a multi-layered, mature offshore oilfield. This field is highly complex vertically with 100s of stacked sandstone packages, with individual thicknesses ranging between 10 to 50 feet, and areally complex through numerous faultblocks, which exhibit varying degrees of inter-fault block communication and aquifer support; it is under primary depletion with gas lift support. Under the current development strategy field performance suggests a moderate ultimate recovery and thus application of water injection and EOR techniques becomes important in view of significant oil volumes being undrained/unswept in the reservoir. Waterflooding, Immiscible Water Alternating Gas (iWAG), Down Dip Gas Injection (DDGI) and Low Salinity Flooding (LSF) have been evaluated as possible technologies for improving the recovery factor of the field; iWAG is the current front running EOR concept. Key considerations are the impact of reservoir heterogeneity on different displacement processes, the importance of gravity forces relative to viscous forces and the representation of the recovery process through choice of appropriate relative permeability and capillary pressure functions. Typically significantly more detail is required in models to assess waterflood and EOR processes than is captured in the models used to manage primary depletion. A particular challenge in this case is the level of complexity in terms of separate reservoirs vertically and areally, which makes the use of full field models with adequate resolution impractical. This paper describes how these challenges have been addressed. Individual reservoirs have been characterised in terms of heterogeneity ranging from broadly coarsening upwards through to fining upwards sequences. A series of sector models with geological "types" representing the range encountered in the field have been constructed and we ensure sufficient grid resolution selection through a step-wise approach which starts with log resolution QC followed by core-to-log integration. Validity checks of the log-to-static model grid through use of Lorenz plots and comparison of their Dykstra Parson coefficients is a key step and provides assurance that the core and log observed heterogeneity is adequately captured in the model resolution. We have found that where the level of heterogeneity is not appropriately represented in the dynamic model the results may lead to selection of the wrong recovery process. Results of our high resolution sector models is consistently assessed by comparing recovery factors as a function of both HCPV throughput and time. This allows poorly performing processes to be deselected and focussing of remaining techniques on the most favourable reservoir types. Final selection of the preferred redevelopment strategy requires an additional step in which reservoir geometry, well count, completion strategies across multiple reservoir intervals and facilities requirements are considered.

The purpose of this study was to assess the knowledge of students of Zahedan University of Medical Sciences about VHI and it's related factors. This cross sectional study was performed on 356 students of Zahedan University of Medical Sciences. The subjects were selected using stratified random sampling. The data collected using structured questionnaire. Maximum score of knowledge was 100. The data were analyzed by SPSS version 13 software using descriptive and analytical (ANOVA, Independent T, Spearman correlation coefficient and chi square tests) statistics. The mean of total score of students were 40.2±18.2. The mean of knowledge score about hepatitis A and E (32.8±22.7), hepatitis B, C and D (47±18.6), about symptoms and treatment (32.1±13.5) and about prevention from these infections was 58±27.3. There was statistically significant relationship between knowledge of students and average, field, semester and graduate level (p

Thinly bedded reservoir pay zones that are commonly deposited in deep water turbidite environment in offshore Sabah area, Malaysia, tend to be inadequately characterized by conventional seismic and logging techniques. Additionally, these pay zones are often overlooked during formation evaluation and even left unexploited as they are finer in resolution (temporal and spatial) than it can be detected by conventional open-hole logs.