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Experimental investigation into effects of the natural polymer and nanoclay particles on the EOR performance of chemical flooding in carbonate reservoirs
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作者 Amir Mohammad Zamani Ashkan Moslemi Kamran Hassani 《Petroleum Science》 SCIE EI CAS CSCD 2024年第2期951-961,共11页
This paper aims to investigate the tragacanth gum potential as a natural polymer combined with natural clay mineral(montmorillonite,kaolinite,and illite)nanoparticles(NPs)to form NP-polymer suspension for enhanced oil... This paper aims to investigate the tragacanth gum potential as a natural polymer combined with natural clay mineral(montmorillonite,kaolinite,and illite)nanoparticles(NPs)to form NP-polymer suspension for enhanced oil recovery(EOR)in carbonate reservoirs.Thermal gravimetric analysis(TGA)tests were conducted initially in order to evaluate the properties of tragacanth gum.Subsequently,scanning electron microscopy(SEM)and energy-dispersive X-ray(EDX)tests were used to detect the structure of clay particles.In various scenarios,the effects of natural NPs and polymer on the wettability alteration,interfacial tension(IFT)reduction,viscosity improvement,and oil recovery were investigated through contact angle system,ring method,Anton Paar viscometer,and core flooding tests,respectively.The entire experiment was conducted at 25,50,and 75℃,respectively.According to the experimental results,the clay minerals alone did not have a significant effect on viscosity,but the addition of minerals to the polymer solution leads to the viscosity enhancement remarkably,resulting mobility ratio improvement.Among clay NPs,the combination of natural polymer and kaolinite results in increased viscosity at all temperatures.Considerable wettability alteration was also observed in the case of natural polymer and illite NPs.Illite in combination with natural polymer showed an ability in reducing IFT.Finally,the results of displacement experiments revealed that the combination of natural polymer and kaolinite could be the best option for EOR due to its substantial ability to improve the recovery factor. 展开更多
关键词 Chemical flooding Tragacanth gum Clay nanoparticle WETTABILITY IFT
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Use of casing and its effect on pressure cells 被引量:4
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作者 AHANGARI K NOORZAD A 《Mining Science and Technology》 EI CAS 2010年第3期384-390,共7页
尽管压力房间成功地被生产并且安装十年了,测量压力的精确性经常是不适当的。由于压力房间和包围媒介的僵硬之间的大差别,应用压力和从压力房间测量了那之间有可观的差别。与僵硬(弹性的模量) 做一个压力房间经常困难、昂贵类似于它... 尽管压力房间成功地被生产并且安装十年了,测量压力的精确性经常是不适当的。由于压力房间和包围媒介的僵硬之间的大差别,应用压力和从压力房间测量了那之间有可观的差别。与僵硬(弹性的模量) 做一个压力房间经常困难、昂贵类似于它将在被嵌入的包围材料。以便改进这种状况,有比例的尺寸的 casing 材料被推荐为一个工具获得可靠结果。在我们的学习,在压力房间的安装使用 casing 的效果被调查,提供 casing 的特征。一些实际建议被介绍用 casing 改进结果的精确性。 展开更多
关键词 压力盒 细胞 套管 测量精度 压力测量 弹性模量 管材料 安装
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Rheological behavior,microstructure and hardness of A356 aluminum alloy in semisolid state using backward extrusion process 被引量:2
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作者 S.A.SADOUGH M.R.RAHMANI V.POUYAFAR 《中国有色金属学会会刊:英文版》 CSCD 2010年第S3期906-910,共5页
The influence of temperature on the flow behavior and rheological characteristics of an A356 alloy in the semi-solid state was investigated using backward extrusion process.Experiments were performed at 5 temperatures... The influence of temperature on the flow behavior and rheological characteristics of an A356 alloy in the semi-solid state was investigated using backward extrusion process.Experiments were performed at 5 temperatures and 4 different wall thicknesses.Viscosities were determined using the force-displacement graphs obtained form back extrusion tests.As observed experimentally,at a constant temperature,the increase of shear rate results in the decrease of alloy viscosity exponentially.Raising the temperature increases the liquid fraction hence reduces the semi-solid alloy viscosity.Metallographic and image analyses show that,because of low forming speed,liquid has time to escape from solid phase forward the sample wall.This condition is the main reason for the segregation phenomenon seen in the base and walls.Vickers hardness test on samples reveals that the hardness increases with the decrease of temperature and wall thickness. 展开更多
关键词 aluminum alloy A356 BACKWARD EXTRUSION SEMISOLID forming RHEOLOGY
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Application of Different Image Processing Techniques on Aster and ETM+ Images for Exploration of Hydrothermal Alteration Associated with Copper Mineralizations Mapping Kehdolan Area (Eastern Azarbaijan Province-Iran) 被引量:2
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作者 Golchin Hajibapir Mohammad Lotfi +1 位作者 Afshar Zia Zarifi Nima Nezafati 《Open Journal of Geology》 2014年第11期582-597,共16页
The Kehdolan area is located at 20 kilometers to the?south-east of Dozdozan Town (Eastern Azarbaijan Province). According to structural geology, volconic rocks are situated in Alborz-Azarbyjan zone, and faults?are?obs... The Kehdolan area is located at 20 kilometers to the?south-east of Dozdozan Town (Eastern Azarbaijan Province). According to structural geology, volconic rocks are situated in Alborz-Azarbyjan zone, and faults?are?observed?in?the?same direction to this system with SE-NW trend. The results show that kaolinite alteration trend with Argilic and propylitic veins?is the?same direction with SW-NE faults in this area. Therefore, these faults with these trends can be considered as the mineralization control for determination of the alterations. Different image processing techniques,?such as false color composite?(FCC), band ratios, color ratio composite?(CRC), principal component?analysis?(PCA), Crosta technique, supervised spectral angle mapping?(SAM), are used for?identification of the alteration zones associated with copper mineralization. In this project ASTER?data are process and spectral analysis to fit for recognizing intensity and kind of argillic, propylitic,?philic, and ETM+ data?which?are process and to fit for iron oxide and relation to metal mineralization of the area. For recognizing different alterations of the study area, some chemical and mineralogical analysis data from the samples showed that ASTER data and ETM+ data were?capable of hydrothermal alteration mapping with copper mineralization.?Copper mineralization in the region is in agreement with argillic alteration. SW-NE trending faults controlled the mineralization process. 展开更多
关键词 Kehdolan Area False COLOR COMPOSITE Band Ratios COLOR Ratio COMPOSITE Principal Component Analysis Crosta Technique Supervised Spectral Angle MAPPING ASTER DATA ETM+ DATA Alteration
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Molecular characterization of sandflies and Leishmania detection in main vector of zoonotic cutaneous leishmaniasis in Abarkouh district of Yazd province,Iran
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作者 Jafari R Najafzadeh N +1 位作者 Sedaghat MM Parvizi P 《Asian Pacific Journal of Tropical Medicine》 SCIE CAS 2013年第10期792-797,共6页
Ohjective:To assess molecular characterization,distribution,seasonal activities of sandfly species and Leishmania parasites infecting them for this zoonotic cutaneous leishmaniasis focus.Methods:The collections were c... Ohjective:To assess molecular characterization,distribution,seasonal activities of sandfly species and Leishmania parasites infecting them for this zoonotic cutaneous leishmaniasis focus.Methods:The collections were carried out in 2009-2011 using CDC traps,Sticky Papers and manual aspirator in and around the villages in Abarkouh district.Individual sandflies were characterized by PCR amplification and sequencing of fragments of their mitochondrial cytochrome b gene.Leishmania parasite infections within sandflies were performed by targeting Cyt b,ITS-rDNA,k-DNA and microsatellite genes.Results:The PCR assays detected only Leishmania major(L.major).All infections(30)were found in the abundant and widespread vector Phlebolomus papalasi(P.papatasi).Small numbers of other sandfly species were also screened for infections,but none was found.Sergentomyia sinloni and P.papalasi were the predominant members in all locations of this district and in all habitats throughout the trapping season.Only five other sandfly species were found,namely Phlebolomus ansari,Phlebotomus caucasicus,Phlebotomus sergenti,Sergentomyia dentata and Sergentomyia merviney.Conclusions:In the current survey,the only infections detected are of L.major in females of P.papatasi(30 out of190).The rates of infection of P.papalasi by L.major are not significantly different in compare with other locations in Iran with no diversity of parasite strains.Zoonotic cutaneous leishmaniasis may have emerged only recently in Abarkouh district,and the reason may well be the instability of the transmission cycles there. 展开更多
关键词 ZOONOTIC cutaneous LEISHMANIASIS PHLEBOTOMUS papatasi LEISHMANIA major SANDFLY Central Iran
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Design a New Model to Evaluate the Ecological Potential Land for Urban Development and Service (City of Zanjan)
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作者 Roghayeh Parchianloo Raziyeh Rahimi +2 位作者 Maryam Kiani Sadr Abdol Reza Karbasi Alireza Gharagozlo 《Open Journal of Ecology》 2017年第9期581-590,共10页
This study aimed to design a new ecological model to be used in ecological land evaluation studies, using careful planning and sustainable resource in the region to develop a sustainable and comprehensive guide. The r... This study aimed to design a new ecological model to be used in ecological land evaluation studies, using careful planning and sustainable resource in the region to develop a sustainable and comprehensive guide. The results show that the study area has grade 1 and 2 urban sustainable planning. Capability Grade 1 has area 149,724.25 hectares equal 22.2% that is stretched from East to West Range. Capability Grade2 has area about 18533.28 hectares equal 2.7% that located in the South, East and South-East. The results show that the greater extent of this range is the unsustainable site, which extends over 506,664.81 hectares, equivalent to 75.1% that areas compliance by the Environmental Protection area. Another important result of this study is unsuitable area for urban development and the range of services already seating workshops and industrial units. This is due to the arrival of adverse environmental effects. Therefore, this study has been focusing on reform of the status of land of use and the optimal use of the ecological potential. 展开更多
关键词 ECOLOGICAL CAPABILITY Assessment URBAN Development GEOGRAPHIC Information System Linear MATHEMATICAL Model
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Rapid detection of coliforms in drinking water of Arak city using multiplex PCR method in comparison with the standard method of culture(Most probably Number)
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作者 Dehghan fatemeh Zolfaghari Mohammad Reza +9 位作者 Arjomandzadegan Mohammad Kalantari Salomeh Ahmari Gholam Reza Sarmadian Hossein Sadrnia Maryam Ahmadi Azam Shojapoor Mana Najarian Negin Kasravi Alii Reza Falahat Saeed 《Asian Pacific Journal of Tropical Biomedicine》 SCIE CAS 2014年第5期404-409,共6页
Objective:To analyse molecular detection of coliforms and shorten the time of PCR.Methods:Rapid detection of coliforms by amplification of lacZ and uidA genes in a multiplex PCR reaction was designed and performed in ... Objective:To analyse molecular detection of coliforms and shorten the time of PCR.Methods:Rapid detection of coliforms by amplification of lacZ and uidA genes in a multiplex PCR reaction was designed and performed in comparison with most probably number(MPN)method for 16 artificial and 101 field samples.The molecular method was also conducted on isolated coliforms from positive MPN samples;standard sample for verification of microbial method certificated reference material;isolated strains from certificated reference material and standard bacteria.The PCR and electrophoresis parameters were changed for reducing the operation time.Results:Results of PCR for lacZ and uidA genes were similar in all of standard,operational and artificial samples and showed the 876 bp and 147 bp bands of lacZ and uidA genes by multiplex PCR.PCR results were confirmed by MPN culture method by sensitivity 86%(95%CI:0.71-0.93).Also the total execution time,with a successful change of factors,was reduced to less than two and a half hour.Conclusions:Multiplex PCR method with shortened operation time was used for the simultaneous detection of total coliforms and Escherichia coli in distribution system of Arak city.It's recommended to be used at least as an initial screening test,and then the positive samples could be randomly tested by MPN. 展开更多
关键词 Water COLIFORMS PCR Rapid detection
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The Role of Life Orientation and Cognitive Regulation on Decreasing Job Stress
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作者 Abbas Sadeghi Aram Yousefi Zahra Khedmati 《Health》 2018年第2期268-281,共14页
The aim of this study is to investigate the relationship between life orientation and cognitive emotion regulation with job stress. On this basis, a sample of 100 employees working in Guilan Education Office was used ... The aim of this study is to investigate the relationship between life orientation and cognitive emotion regulation with job stress. On this basis, a sample of 100 employees working in Guilan Education Office was used and research hypotheses were examined by job stress, life orientation and cognitive emotion regulation questionnaires. The results of this study indicate that job stress has a significant relationship with life orientation (-0.32), self-blame (0.25), rumination (-0.36), positive refocusing (0.25), positive refocusing on program (-0.21), positive reappraisal (-0.28), catastrophizing (-0.39) and other blames (-0.25). Furthermore, life orientation and cognitive regulation could explain 22% variances in respondents’ job stress. This finding indicates that more positive life orientation and subsequent decrease of emotion-regulation-related disorders will lead to less job stress. 展开更多
关键词 Job Stress COGNITIVE Emotion REGULATION LIFE ORIENTATION WORKPLACE
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Electromagnetic Self-Force Mechanisms and Origin of <i>R</i><sup>-1</sup>Term
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作者 Saeed Fathi Hamed Razavi 《Journal of Applied Mathematics and Physics》 2017年第5期1099-1105,共7页
An accelerating charged particle exerts a force upon itself. If we model the particle as a spherical shell of radius R, and calculate the force of one piece of this shell on another and eventually integrate over the w... An accelerating charged particle exerts a force upon itself. If we model the particle as a spherical shell of radius R, and calculate the force of one piece of this shell on another and eventually integrate over the whole particle, there will be a net force on the particle due to the breakdown of Newton’s third law. This symmetry breaking mechanism relies on the finite size of the particle;thus, as Feynman has stated, conceptually this mechanism doesn’t make good sense for point particles. Nonetheless, in the point particle limit, two terms survive in the self-force series: R0 and R-1 terms. The R0 term can alternatively be attributed to the well-known radiation reaction but the origin of R-1 term is not clear. In this study, we will show that this new term can be accounted for by an inductive mechanism in which the changing magnetic field induces an inductive force on the particle. Using this inductive mechanism, we derive R-1 term in an extremely easy way. 展开更多
关键词 ELECTROMAGNETIC Self-Force Self-Force Mechanisms Radiation Reaction Faraday’s Law of Induction
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Iranian English Foreign Language Learners' Learning Style Sensory Preferences and Their Speaking Strategy Use Across Proficiency
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作者 Tania Samadian Parviz Birjandi 《Sino-US English Teaching》 2015年第10期745-750,共6页
关键词 外语学习 英语学习 伊朗 偏好 运用能力 风格 口语 多元方差分析
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Lower Intermediate Readers and Their Use of Cognitive and Metacognitive Strategies
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作者 Parisa Daftarifard Parviz Birjandi 《Sino-US English Teaching》 2015年第10期757-761,共5页
关键词 认知策略 学习成绩 读者 英语考试 指令周期 证书
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A muscle spindle model and study the effects of static and dynamic γ stimulations on primary and secondary ending outputs
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作者 Glayol Nazari Golpayegani Amir Homayoun Jafari 《Journal of Biomedical Science and Engineering》 2009年第3期158-165,共8页
A muscle spindle model and study the effects of static and dynamic γ stimulations on primary and secondary ending
关键词 MODELING MUSCLE SPINDLE POSTURAL Control SYSTEMS
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Copper, Zinc, and Lead Mineral Prospectivity Mapping in the North of Tafresh, Markazi Province, Central Iran, Using the AHP-OWA Method
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作者 Masoumeh Mahbouby Niyeh Alireza Jafarirad +1 位作者 Jalal Karami Saeed Jabbari Bokani 《Open Journal of Geology》 2017年第4期533-558,共26页
The reason of this research is to identify the favorable areas for copper, zinc, and lead mineralization in the western part of the 1:100,000 Tafresh geological Sheet in the Urmia-Dokhtar structural zone of Iran. Effe... The reason of this research is to identify the favorable areas for copper, zinc, and lead mineralization in the western part of the 1:100,000 Tafresh geological Sheet in the Urmia-Dokhtar structural zone of Iran. Effective data layers for mineralization, such as geology, geochemistry, structures, and satellite images, were analyzed and then integrated using the AHP-OWA method to identify favorable areas. Geochemical stream samples were analyzed by univariate, multivariate, and classical statistical methods and revealed the first, second, and third class anomalies for copper, zinc, and lead in the study region. Detection of hydrothermal alteration zones by Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) satellite imagery in various algorithms, such as Relative absorption Band Depth (RBD), Minimum Noise Fraction (MNF), and Least Square Fit (LS-Fit), shows that argillic, phyllic, propylitic, and iron oxide alterations develop around the faults in the area under study. The favorable areas for copper, zinc, and lead mineralization have been identified by a combination of evidence maps of lithology, faults, dikes, geochemistry, and alteration data layers. Field observations in the area under study have confirmed the results. 展开更多
关键词 MINERAL Prospectivity Tafresh Urmia-Dokhtar STREAM Sample Remote Sensing AHP-OWA
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Studying Subsidence Coefficient of Mirages and Dynamic Storage Volume of Karstic Springs of Khorram Abad, West of Iran
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作者 Vidafar Milad Mohamad Reza Ahmadipour Reza Zarei Sahamiyeh 《Open Journal of Geology》 2016年第6期372-375,共4页
The studied subject is about subsidence coefficient of mirages and dynamic storage volume of Karstic springs in Khorram Abad in West of Iran. Subsidence coefficient indicates ability of groundwater discharge and hydro... The studied subject is about subsidence coefficient of mirages and dynamic storage volume of Karstic springs in Khorram Abad in West of Iran. Subsidence coefficient indicates ability of groundwater discharge and hydrologic properties of the environment;meaning effective porosity and transfer coefficient of springs. In general, in developed Karstic zones, each direct line of subsidence curve indicates a discharge regime. Obtained results from the study show that subsidence branch of Golestan, Motahari, Niloofar (changaei), Navekech, Dore Robat mirages have subsidence coefficient with mild slope and low value, which demonstrate passage of water through a seams system at the karst springs. Q and whirlpool stone mirages have two subsidence coefficients, which indicate passage of water through two seam systems in Karstic environment of springs. According to obtained results, process of changes in subsidence branch in these mirages has had at the first a mild slope and low discharge coefficient and in continue, its discharge would be declined with sharper slope and high discharge coefficient. In order to estimate dynamic storage volume of springs, MAILET general equation is applied, which is suitable for subsidence branch of hydrographs of centralized springs discharge. Following, dynamic storage volume of studied springs is analyzed and obtained results are presented in this study respectively. 展开更多
关键词 Subsidence Coefficient MIRAGE Dynamic Storage Karstic Springs Khorram Abad
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Measuring Tumor Necrosis Factor-Alpha and Interleukin-1 Beta Levels in Mustard Gas Exposed Patients
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作者 Hoda Sheibani Mohammad Goudarzi +2 位作者 Malek Ashtar Esfandiari Fatemeh Rousta Reza Haji Hosseini 《Advances in Bioscience and Biotechnology》 2017年第4期134-141,共8页
Sulfur mustard (SM) is an alkalizing chemical which has been used mostly as a weapon all over the world. Sulfur mustard can cause damages to many organs, especially the skin, respiratory system and the eyes. Generally... Sulfur mustard (SM) is an alkalizing chemical which has been used mostly as a weapon all over the world. Sulfur mustard can cause damages to many organs, especially the skin, respiratory system and the eyes. Generally, many complications of mustard gas result from its alkalizing potency and reaction with cellular components like DNA, RNA, proteins and lipid membranes. The damages caused by SM will lead to many complications which persist during the lifespan of exposed subjects. Pro-inflammatory cytokines including especially TNF-α and IL-1β can cause systemic inflammatory reactions and vast changes like altered cell signaling, migration, cytokine production changes and fever. This study was designed to analyze cytokine levels in mustard-gas-exposed people’s serum in the war between Iraq and Iran, who had the chronic dry-eye symptoms compared to the normal group, 30 years after exposure. In this study, 25 veterans who were exposed to mustard gas were compared to 25 healthy people as control group. The veterans with concurrent involvement of eye, lung, and skin were selected. We used ELISA method to assess the levels of TNF-α and IL-1β in serum of people in both groups. All the results analyzed with T-test in SPSS 17 statistical software. The mean levels of TNF-α and IL-1β in serum of chemical exposed veterans were 52.3 ± 1.4 pg/ml and 3.43 ± 0.3 pg/ml while in the control group were 19.5±1.3 pg/ml and 2.25 ± 0.2 pg/ml, respectively. In the control group, the serum pro-inflammatory cytokine levels were significantly lower than the exposed group (P < 0.05). This study showed that there is a meaningful difference between TNF-α and IL-1β serum levels in the SM exposed group compared to the control group. There are some differences between the present study and others. However, studies on local inflammatory changes in these patients are also limited and need more reviews. 展开更多
关键词 MUSTARD Gas (SM) CYTOKINE TNF-α and IL-1Β
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Petrography, Temperature Measurement, and Economic Evaluation of Granitoid Pluton of Qohrud-Kashan Using EPMA, XRD, and XRF Analysis
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作者 Afshin Ashja Ardalan Mina Khodadady +3 位作者 Mohammad Hashem Emami Jamal Sheikh Zakariaie Mohammad Hosein Razavi Abdollah Yazdi 《Open Journal of Geology》 2014年第8期406-424,共19页
The area which is being studied is located in northwest of Isfahan, 30 kilometers south of Kashan, and southern section of Qmasar. The longitude of the area of study is 51°19'13"E to 51°26'26&qu... The area which is being studied is located in northwest of Isfahan, 30 kilometers south of Kashan, and southern section of Qmasar. The longitude of the area of study is 51°19'13"E to 51°26'26"E and its latitude is 33°34'24"N to 33°44'24"N. Based on microscopic observations, modal analysis, and also based on their location in the Streckeisen [QAPF], both the stones of the Qohrud batholitic mass themselves and its enclaves are more in quartz monzonite ranges. Granitoid also have quartz monzonite enclaves. These enclaves are from both microgranular mafic and Autolith types which indicate the mixing of two magmas. At the center of the pluton, there are indications of existence of main magma reservoir and magma mixing. In terms of mineralogy, the granitoid rocks of the area very much resemble I-type. The zoning of the plagioclases is both the normal kind and variation invert and has andesine general composition. The probed biotite sample contains iron and belongs to a granitic sample from the center of the mass. Also, the ranking graph indicates biotite as the source of recrystallization for the analyzed points. The probed biotite sample of the Qohrud area showed formation temperature of 730 degrees centigrade. According to the Rb and Sr contents, the source of the rocks is at depths of 20 to 30 kilometers from the earth’s surface that are depending on the subduction zone. The formation temperature of the specimens of the Qohrud batholithic mass is mostly between 900 to 1000 degrees centigrade. [At] the center of the mass (around Qahrud), the amount of molybdenum is higher than the economic limit. 展开更多
关键词 Kashan Qohrud GRANITOID TEMPERATURE Measurement Analysis
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Development and Validation of Supervision Scale in Phone Consultation in Iran
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作者 Mahmood Dehghani Samaneh Ghafoori +3 位作者 Samiyeh Panahandeh Komeil Zahedi Nahid Honarmand Arezo Zokaeefar 《Open Journal of Medical Psychology》 2017年第2期144-152,共9页
The purpose of the present research is to develop and validate an instrument for supervision in phone consultation. Literature review and focus group discussion in the first stage led to the extraction of twenty items... The purpose of the present research is to develop and validate an instrument for supervision in phone consultation. Literature review and focus group discussion in the first stage led to the extraction of twenty items for the supervision scale. After the initial administration and the group work of the specialized team and upon receiving the feedback, the repetitive and overlapping items were deleted and ten important items were selected. Finally, the instrument was administered on 499 consolers of phone consultation in 19 provinces of Iran, consisted of male and female individuals cooperating in the counselor’s voice. The consolers were trained and assessed by 96 supervisors. The supervisors consisted of male and female supervisors introduced as supervisors by the State Welfare Organization of Iran in different provinces all over the country. This study was conducted in State Welfare Organization of Iran. The exploratory factor analysis on the supervision scale revealed two dimensions: therapeutic alliance and intervention. The result showed the supervision scale was a valid and reliable instrument for assessing the consultation process in the semi-structured model of phone consultation. The finding is in line with previous studies in terms of therapeutic alliance, intervention in the semi-structured model of phone consultation. 展开更多
关键词 SUPERVISOR SUPERVISION PHONE CONSULTATION
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Reserve estimation of an open pit mine under price uncertainty by real option approach 被引量:8
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作者 AKBARI Afshin Dehkharghani OSANLOO Morteza SHIRAZI Mohsen Akbarpour 《Mining Science and Technology》 EI CAS 2009年第6期709-717,共9页
Reserve estimation is a key to find the correct NPV in a mining project. The most important factor in reserve estimation is the metal price. Metal price fluctuations in recent years were exaggerated, and imposed a hig... Reserve estimation is a key to find the correct NPV in a mining project. The most important factor in reserve estimation is the metal price. Metal price fluctuations in recent years were exaggerated, and imposed a high degree of uncertainty to the reserve estimation, and in consequence to the whole mine planning procedure. Real option approach is an efficient method of decision making in the uncertain conditions. This approach has been used for evaluation of defined natural resources projects until now. This study considering the metal price uncertainty used real option approach to prepare a methodology for reserve estimation in open pit mines. This study was done on a copper cylindrical deposit, but the achieved methodology can be adjusted for all kinds of deposits. This methodology was comprehensively described through the examples in such a manner that can be used by the mine planners. 展开更多
关键词 实物期权方法 价格波动 不确定性 露天矿 估计 储备 储量计算 资源评价
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Analytical solutions to nonlinear conservative oscillator with fifth-order nonlinearity 被引量:4
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作者 M.G.Sfahani S.S.Ganji +2 位作者 A.Barari H.Mirgolbabaei G.Domairry 《Earthquake Engineering and Engineering Vibration》 SCIE EI CSCD 2010年第3期367-374,共8页
This paper describes analytical and numerical methods to analyze the steady state periodic response of an oscillator with symmetric elastic and inertia nonlinearity. A new implementation of the homotopy perturbation m... This paper describes analytical and numerical methods to analyze the steady state periodic response of an oscillator with symmetric elastic and inertia nonlinearity. A new implementation of the homotopy perturbation method (HPM) and an ancient Chinese method called the max-rain approach are presented to obtain an approximate solution. The major concern is to assess the accuracy of these approximate methods in predicting the system response within a certain range of system parameters by examining their ability to establish an actual (numerical) solution. Therefore, the analytical results are compared with the numerical results to illustrate the effectiveness and convenience of the proposed methods. 展开更多
关键词 non-linear oscillation homotopy perturbation method (HPM) max-min approach (MMA) Rung-Kutta method (R-KM) large amplitude free vibrations
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Mechanical properties of TiO_2-hydroxyapatite nanostructured coatings on Ti-6Al-4V substrates by APS method 被引量:2
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作者 Mohammad Zakeri Elmira Hasani Morteza Tamizifar 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2013年第4期397-402,共6页
TiO2-hydroxyapatite (HA) nanostructured coatings were produced by atmospheric plasma spray method. The effects of starting powder composition and grain size on their mechanical properties were investigated. The micr... TiO2-hydroxyapatite (HA) nanostructured coatings were produced by atmospheric plasma spray method. The effects of starting powder composition and grain size on their mechanical properties were investigated. The microstructure and morphology were characterized by X-ray diffraction and scanning electron microscopy (SEM). It is found that the coating with 10% HA has the best mechanical properties. Based on Rietveld refinement method, the mean grain size of the as-received powder (212 nm) extensively decreases to 66.4 nm after 20 h of high-energy ball milling. In spite of grain growth, the deposited coatings maintain their nanostructures with the mean grain size of 112 nm. SEM images show that there is a lower porosity in the coating with a higher HA content. Optical microscopy images show that uniform thickness is obtained for all the coatings. 展开更多
关键词 titanium dioxide HYDROXYAPATITE plasma spraying nanostructures composite coatings mechanical proper-ties titanium alloys
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