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Reliability-based maintenance scheduling of hydraulic system of rotary drilling machines

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International Journal of Mining Science and Technology 2013年第5期23卷 771-775页

作者： Mohammad Javad Rahimdel Mohammad Ataei Reza Khalokakaei seyed hadi hoseinie Faculty of Mining Engineering Sahand University of Technology Faculty of Mining Engineering Geophysics and PetroleumShahrood University of Technology Division of Operation and Maintenance Engineering Lulea University of Technology

Hydraulic system has a critical and important role in drilling *** failure in this system leads to problems in power system and machine *** the failure cannot be prevented entirely,it is important to minimize its *** is one of the most effcient and important method to study safe operation probability of hydraulic *** this research,the reliability of hydraulic system of four rotary drilling machines in Sarcheshmeh Copper Mine in Iran has been *** data analysis shows that the time between failures(TBF)of Machines A and C obey the Weibull(2P)and Weibull(3P)distribution,***,the TBF of Machines B and D obey the lognormal *** regard to reliability plots of hydraulic systems,preventive reliability-based maintenance time intervals for 80%reliability levels for machines in this system are 10 h.

关键词： Reliability Drilling Hydraulic Maintenance

Reliability and maintainability analysis of electrical system of drum shearers

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Journal of Coal Science & Engineering(China) 2011年第2期17卷 192-197页

作者： seyed hadi hoseinie MOHAMMAD Ataei REZA Khalokakaie UDAY Kumar Faculty of Mining Petroleum ＆ Geophysics Shahrood University of Technology Shahrood *** Iran Division of Operation and Maintenance Engineering Lulea University of Technology Lulea 97187 Sweden

The reliability and maintainability of electrical system of drum shearer at Parvade. 1 Coal Mine in central Iran was analyzed. The maintenance and failure data were collected during 19 months of shearer operation. According to trend and serial correlation tests, the data were independent and identically distributed （iid） and therefore the statistical techniques were used for modeling. The data analysis show that the time between failures （TBF） and time to repair （TTR） data obey the lognormal and Weibull 3 parameters distribution respectively. Reliability-based preventive maintenance time intervals for electrical system of the drum shearer were calculated with regard to reliability plot. The reliability-based maintenance intervals for 90%, 80%, 70% and 50% reliability level are respectively 9.91, 17.96, 27.56 and 56.1 h. Also the calculations show that time to repair （TTR） of this system varies in range 0.17-4 h with 1.002 h as mean time to repair （MTTR）. There is a 80% chance that the electrical system of shearer of Parvade. 1 mine repair will be accomplished within 1.45 h.

关键词： drum shearer electrical system reliabilitv maintenance

Reliability modeling of hydraulic system of drum shearer machine

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Journal of Coal Science & Engineering(China) 2011年第4期17卷 450-456页

作者： seyed hadi hoseinie MOHAMMAD Ataie REZA Khalookakaei UDAY Kumar Faculty of Mining Petroleum ＆ Geophysics Shahrood University of Technology Shahrood *** Iran Division of Operation and Maintenance Engineering Lulea University of Technology Lulea 97187 Sweden

The hydraulic system plays an important role in supplying power and its transition to other working parts of a coal shearer machine. In this paper, the reliability of the hydraulic system of a drum shearer was analyzed. A case study was done in the Tabas Coal Mine in Iran for failure data collection. The results of the statistical analysis show that the time between failures （TBF） data of this system followed the 3-parameters Weibull distribution. There is about a 54% chance that the hydraulic system of the drum shearer will not fail for the first 50 h of operation. The developed model shows that the reliability of the hydraulic system reduces to a zero value after approximately 1 650 hours of operation. The failure rate of this system decreases when time increases. Therefore, corrective maintenance （run-to-t^ailure） was selected as the best maintenance strategy for it.

关键词： reliability modeling hydraulic system drum shearer maintenance strategy

Arrhenius parameters determination in non-isothermal conditions for mechanically activated Ag_2O-graphite mixture

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Transactions of Nonferrous Metals Society of China 2014年第12期24卷 3994-4003页

作者： seyed hadi SHAHCHERAGHI Gholam Reza KHAYATI Department of Mineral Processing Engineering Shahid Bahonar University of Kerman Department of Materials Science and Engineering Shahid Bahonar University of Kerman

The non-isothermal kinetics of mechanochemical reduction of Ag2O with graphite was studied by DSC and TGA with a model of fitting Malek approach and a model-free advanced isoconversional method of Vyazovkin. To evaluate the kinetics parameters, Ag2O–graphite mixture of as-received and milled for 2 and 4 h samples were selected. Based on the results obtained by Vyazovkin method calculation, however, the difference between the maximum and minimum values of activation energy is less than 20%-30%of the average activation energy （（99.38±2.36） kJ/mol） and thermal decomposition of mechanically activated Ag2O for 2 h is a multi-step process. Moreover, the thermal decomposition of mechanically activated Ag2O–graphite powder activated for 4 h is a single-step process （the average activation energy=（93.68±2.26） kJ/mol）. The kinetics modeling shows that the complexity of thermal decomposition of as-received Ag2O–graphite mixture is higher than that of the others. While, the autocatalytic tendency of as-received Ag2O–graphite mixture is lower than that of the others.

关键词： mechanical activation Vyazovkin method kinetic modeling Sestak-Berggren model integral master plot method silver oxide

Kinetics analysis of non-isothermal decomposition of Ag_2O-graphite mixture

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Transactions of Nonferrous Metals Society of China 2014年第9期24卷 2991-3000页

作者： seyed hadi SHAHCHERAGHI Gholam Reza KHAYATI Department of Mineral Processing Engineering Shahid Bahonar University of KermanKerman Iran Department of Materials Science and Engineering Shahid Bahonar University of KermanKerman Iran

The thermal decomposition kinetics of Ag2O-graphite mixture was systematically studied using a differential scanning calorimeter（DSC） in terms of model-fitting Malek approach, integral master plot method and model-free advanced isoconversional method of Vyazovkin. The results showed that the thermal decomposition occurred in two stages. The first step was the decomposition process of Ag2 O to form porous silver particles as a complex process with the participation of at least two mechanisms, and the second step corresponded to the structural change from porous particles to silver bulk crystals as a single-step process.

关键词： Ag2O advanced isoconversional method kinetic modeling Sestak–Berggren model

Reservoir volume optimization and performance evaluation of rooftop catchment systems in arid regions: A case study of Birjand, Iran

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Water Science and Engineering 2017年第2期10卷 125-133页

作者： Zinat Komeh hadi Memarian seyed Mohammad Tajbakhsh Faculty of Natural Resources and Environment University of Birjand Birjand 97175 Iran

This study evaluated the performance of rooftop catchment systems in securing non-potable water supply in Birjand, located in an arid area in southeastern Iran. The rooftop catchment systems at seven study sites of different residential buildings were simulated for dry, normal, and wet water years, using 31-year rainfall records. The trial and error approach and mass diagram method were employed to optimize the volume of reservoirs in five different operation scenarios. Results showed that, during the dry water year from 2000 to 2001, for reservoirs with volumes of 200-20000 L, the proportion of days that could be secured for non-portable water supply was on average computed to be 16.4%-32.6% across all study sites. During the normal water year from 2009 to 2010 and the wet water year from 1995 to 1996, for reservoirs with volumes of 200-20000 L, the proportions were 20.8%-69.6% and 26.8%-80.3%, respectively. Therefore, a rooftop catchment system showed a high potential to meet a significant portion of non-potable water demand in the Birjand climatic region. Reservoir volume optimization using the mass diagram method produced results consistent with those obtained with the trial and error approach, except at sites #1, #2, and #5. At these sites, the trial and error approach performed better than the mass diagram method due to relatively high water consumption. It is concluded that the rooftop catchment system is applicable under the same climatic conditions as the study area, and it can be used as a drought mitigation strategy as well.

关键词： Mass diagram analysis Non-potable water demand Reservoir volume optimization Rooftop catchment Rainwater harvesting

Reaction pathway and kinetics of CdO nanoparticles prepared from CdCO_3 precursor using thermal decomposition method

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Transactions of Nonferrous Metals Society of China 2016年第4期26卷 1138-1145页

作者： Gholam Reza KHAYATI seyed hadi SHAHCHERAGHI Vahid LOTFI Esmael DAREZARESHKI Department of Materials Science and Engineering Shahid Bahonar University of KermanP.O.Box No.76135-133KermanIran Department of Advanced Science and Technology Shahid Bahonar University of KermanP.O.Box No.76135-133KermanIran Mineral Industries Research Centre Shahid Bahonar University of KermanP.O.Box No.76135-133KermanIran

The non-isothermal kinetics of CdO nanoparticles prepared from CdCO3 precursor using thermal decomposition method was investigated. A model-fitting Malek approach and a model-free advanced isoconversional method of Vyazovkin were applied to the analysis of the DSC and TGA data. The results showed that CdO nanoparticles prepared from CdCO3 followed an autocatalytic reaction. Sestak–Berggren model could favorably describe the studied reaction process. Moreover, the apparent activation energy of CdCO3 decomposition was calculated to be (119.19±9.97) kJ/mol and the explicit rate equation form of CdCO3 decomposition was established.

关键词： CdCO_3 CdO nanoparticle kinetic modeling thermal decomposition advanced isoconversional method

Vegetation composition differentiation and species-environment relationships in the northern part of Isfahan Province, Iran

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Journal of Arid Land 2017年第2期9卷 161-175页

作者： hadi KARGAR-CHIGANI seyed Akbar JAVADI Ghavamodin ZAHEDI-AMIRI seyed Jamaleddin KHAJEDDIN Mohamad JAFARI Department of Range Management Science and Research Branch Islamic Azad University Faculty of Natural Resources University of Tehran Range and Watershed Management Division Department of Natural Resources Isfahan University of Technology

A considerable proportion of Iran＇s territory is covered with arid and semi-arid rangelands and mismanagement and overexploitation of those rangelands have resulted in serious ecological degradation. Thus, the need is pressing to examine the present species composition and the relationships with environmental factors for providing the needed scientific references to species conservation and ecological rehabilitation efforts. The aims of this study were to examine the species composition and to delineate the most important factors influencing the distributions of plant species and groups in the northern rangelands of Isfahan Province （Iran） using two-way indicator species analysis （TWINSPAN）, detrended correspondence analysis （DCA）, principal component analysis （PCA）, and canonical correspondence analysis （CCA）. Field investigations were conducted in the growing season of 2014 using stratified random method in 22 homogeneous sampling units. In total, 75 plant species belonging to 52 genera and 19 families were identified. The most important families were Asteraceae and Papilionaceae, the most important genera were Astragalus, Cousinia, and Acanthophyllum, and the most important species were Artemisia aucheri and Artemisia sieberi. Plant species were classified into 10 groups using TWINSPAN. DCA was used to estimate the magnitude of changes in species composition along the first two ordination axes to provide gradient length estimations for PCA and CCA ordinations. The first three PCA axes and the first three CCA axes demonstrated similar cumulative percentage of variance, indicating that the environmental factors （selected by PCA） used in CCA ordination were acceptable for explaining the species composition and the distributions. CCA ordination showed that the first axis was closely related to elevation, slope, surface bare soil cover, surface litter cover, gravel proportion, organic matter, total nitrogen, CaCO3 content, and grazing intensity and that the second axi

关键词： rangeland classification ordination multivariate analysis plant groups Isfahan Province

Comparison of different diagnostic methods in infants with Cholestasis

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World Journal of Gastroenterology 2006年第36期12卷 5893-5896页

作者： seyed Mohsen Dehghani Mahmood Haghighat Mohammad hadi Imanieh Bita Geramizadeh Department of Pediatric Gastroenterology Gastroenterohepatology Research Center of Nemazee Hospital Shiraz University of Medical Sciences Shiraz Iran Department of Pathology Nemazee Hospital Shiraz University of Medical Sciences Shiraz Iran

AIM: To evaluate different methods in differentiating idiopathic neonatal hepatitis from biliary atresia. METHODS: Sixty-five infants with cholestatic jaundice and final diagnosis of idiopathic neonatal hepatitis and biliary atresia were studied prospectively from September 2003 to March 2006. A thorough history and physical examination were undertaken and the liver enzymes were examined. All cases underwent abdominal ultrasonography, hepatobiliary scintigraphy, and percutaneous liver biopsy. The accuracy, sensitivity, specificity and predictive values of these various methods were compared. RESULTS: There were 34 girls and 31 boys, among them 46 subjects had idiopathic neonatal hepatitis (age, 61 ± 17 d) and 19 had biliary atresia (age, 64 ± 18 d). The mean age at onset of jaundice was significantly lower in cases of biliary atresia when compared to idiopathic neonatal hepatitis cases (9 ± 13 d vs 20 ± 21 d; P = 0.032). The diagnostic accuracy of different methods was as follows: liver biopsy, 96.9%; clinical evaluation, 70.8%; ultrasonography, 69.2%; hepatobiliary scintigraphy, 58.5%; and liver enzymes, 50.8%.CONCLUSION: Our results indicate that clinical evaluation by an experienced pediatric hepatologist and a biopsy of the liver are considered as the most reliable methods to differentiate idiopathic neonatal hepatitis and biliary atresia.

关键词： Idiopathic neonatal hepatitis Biliary atresia Clinical evaluation Liver biopsy