Peat forming environment strongly influences the economic value of any coal seam and coal-bearing strata.Hence,pal-aeoenvironmental studies provide important information for coal resource exploration.In this context,d...Peat forming environment strongly influences the economic value of any coal seam and coal-bearing strata.Hence,pal-aeoenvironmental studies provide important information for coal resource exploration.In this context,detailed studies on selected coals from the Parvadeh Area,Iran,were conducted using sedimentology,coal petrology,X-ray diffraction(XRD),scanning electron microscopy-energy dispersive X-ray analyzer(SEM-EDX),and proximate analysis.The sedi-mentary facies above and below the coal seams are mainly marine or marine-influenced facies,supporting that the coal-forming mires in the Parvadeh Area developed in a paralic environment,where the base level must be closely related to sea level.Sulfur contents are moderate to high and mark the influence of brackish/marine water,especially during transgres-sion after peat growth in a lower delta plain environment.The peat-forming mires extended on coastal/delta plain lobes.The lower delta plain/coastal plain coals are characterized by lateral continuity and substantial thickness,whereas few coals possibly representing the upper delta plain are thin and more discontinuous.The detrital nature and composition of the numerous partings and the overall high ash yield in the coal seams indicate an active tectonic area with high rates of creation of accommodation space over peat growth.Coal petrology and coal facies analysis exhibits a permanently high water table within a forest swamp and mostly rheotrophic conditions,sometimes with connection to the seawater.Accord-ing to paleoenvironmental reconstructions,it seems that coal layers may be thicker,with less sulfur(pyrite),but more clastic minerals and partings toward the western part of the area.Although these coal seams presently have low economic potential for the mining operation,partly due to great depth,this humic,high-volatile to medium-volatile bituminous coal may be suitable for exploration of coal bed methane resources.展开更多
In this research, Tabas area, which is located in central Iran, was selected as the study area and three geomorphic indices were calculated for its structural fronts. Through averaging these three indices, we obtained...In this research, Tabas area, which is located in central Iran, was selected as the study area and three geomorphic indices were calculated for its structural fronts. Through averaging these three indices, we obtained index of active tectonics (IAT). The values of the index were divided into classes to define the degree of active tectonics. Therefore, relative tectonic activity was calculated and their values were classified and analyzed in two groups. Regions were identified as high and moderate levels. In analyzing data and combining them with tectonic setting, the results were often associated and justified with regional geology. Our results show that the highest value is located along Shoutori fault, which shows 2 class of relative tectonic activity (high level). Also, moderate values are located along Ereshk, Ezmeighan and Jamal faults (moderate level). According to these results, Shoutori fault is the most active fault in the study area and this situation is compatible with its position as a mountain front fault.展开更多
This paper presents organic geochemical evidence pointing to the occurrence of wildfire events at the Triassic-Jurassic boundary in Central Iran.The studied outcrop section(the Kamarmacheh Kuh section)is comprised of ...This paper presents organic geochemical evidence pointing to the occurrence of wildfire events at the Triassic-Jurassic boundary in Central Iran.The studied outcrop section(the Kamarmacheh Kuh section)is comprised of the Upper Triassic Nayband Formation which passes conformably into the Lower Jurassic Ab-e-Haji Formation with no sharp boundary.Organic petrographical studies reveal a higher concentration of semi-fusinite macerals and microscopic charcoal at the boundary between studied formations.This observation can be an evidence for widespread wildfire events at the Triassic-Jurassic boundary of the studied area.Following these fires,vast areas of land were exposed for erosion and large volumes of clastic sediments were provided due to increased run-off.This agrees well with previous sedimentological and stratigraphical studies suggesting a major change in the depositional conditions from marine to non-marine at the Triassic-Jurassic boundary of the Tabas Basin.These findings can have important implications about paleo-depositional settings of the studied formations and the nature of the associated organic matter.展开更多
This article addresses three large earthquake disasters in Iran: Tabas in 1978, Rudbar in 1990, and Bam in 2003. Lessons and 'Lessons Learned' from these three earthquake disasters were investigated together w...This article addresses three large earthquake disasters in Iran: Tabas in 1978, Rudbar in 1990, and Bam in 2003. Lessons and 'Lessons Learned' from these three earthquake disasters were investigated together with their contributions over time towards earthquake disaster risk reduction in Iran. Many lessons from 1978 Tabas, 1990 Rudbar, and 2003 Bam did not become 'Lessons Learned' and they were identified again within the dramatic context of other earthquake disasters in various places of Iran. Both lessons and 'Lessons Learned' from Tabas, Rudbar, Bam,and other earthquake disasters in Iran require a sustainable long-term framework—an earthquake culture.展开更多
A pplication o f m echanical excavators is one o f th e m o st com m only used excavation m eth o d s because itcan bring th e p ro ject m ore productivity, accuracy and safety. A m ong th e m echanical excavators, ro...A pplication o f m echanical excavators is one o f th e m o st com m only used excavation m eth o d s because itcan bring th e p ro ject m ore productivity, accuracy and safety. A m ong th e m echanical excavators, roadhead ers are m echanical m iners w h ich have b een extensively u se d in tu n n elin g , m ining an d civil indu stries. Perform ance pred ictio n is an im p o rta n t issue for successful ro a d h e a d e r application andgenerally deals w ith m achine selection, p ro d u ctio n rate an d b it consu m p tio n . The m ain aim o f thisresearch is to investigate th e c u ttin g p erfo rm an ce （in stan tan eo u s c u ttin g rates （ICRs）） o f m ed iu m -d u tyro ad h ead ers by using artificial neural n etw o rk （ANN） approach. T here are d ifferent categories forANNs, b u t based o n train in g alg o rith m th e re are tw o m ain k in d s： supervised and u n su p erv ised . Them u lti-lay er p ercep tro n （MLP） an d K ohonen self-organizing feature m ap （KSOFM） are th e m o st w idelyused neu ral netw o rk s for supervised an d u n su p erv ised ones, respectively. For gaining this goal, ad atab ase w as prim arily provided from ro ad h e a d e rs＇ p erfo rm an ce an d geom echanical characteristics o frock form ations in tu n n els and d rift galleries in Tabas coal m ine, th e larg est an d th e only fullymech an ized coal m ine in Iran. T hen th e datab ase w as analyzed in o rd e r to yield th e m ost im p o rtan tfactor for ICR by using relatively im p o rta n t factor in w hich G arson eq u atio n w as utilized. The MLPn etw o rk w as train ed by 3 in p u t p ara m e te rs including rock m ass pro p erties, rock quality d esignation（RQD）, in tact rock p ro p erties such as uniaxial com pressive stre n g th （UCS） an d Brazilian ten sile stren g th（BTS）, and o n e o u tp u t p a ra m e te r （ICR）. In o rd e r to have m ore v alidation o n MLP o u tp u ts, KSOFM visualizationw as applied. The m ean square e rro r （MSE） an d regression coefficient （R ） o f MLP w e re found tobe 5.49 an d 0.97, respectively. M oreover, KSOFM n etw o rk has a m ap size o f 8 x 5 and final qu an tizatio nan d topographic erro rs w e re 0.383 an d 0.032, respectively. The results show th a t MLP neural n etw orkshave a strong capability to p red ict an d ev alu ate th e perfo rm an ce o f m ed iu m -d u ty ro ad h ead ers in coalm easu re rocks. Furtherm ore, it is concluded th a t KSOFM neural n etw o rk is an efficient w ay for u n d e rstand in g system beh av io r an d know ledge extraction. Finally, it is indicated th a t UCS has m ore influenceo n ICR b y applying th e b e st train ed MLP n etw o rk w eig h ts in G arson eq u atio n w h ich is also confirm ed byKSOFM.展开更多
Prediction of roadheader performance plays a significant role in the plan of tunnel construction, which is influenced by different key parameters, including rock strength, discontinuity in rock mass, type and specific...Prediction of roadheader performance plays a significant role in the plan of tunnel construction, which is influenced by different key parameters, including rock strength, discontinuity in rock mass, type and specifications of roadheader machine, and brittleness. The main aim of this study is to build a robust empirical equation based on rock mass properties for the roadheader performance prediction. For achieving the aim, a dataset composed of roadheader performance rate and rock properties is established using the dataset compiled from an underground coal mine located in a remote rugged desert environment some 85 km south of Tabas City in mid east Iran. By using gathered data, the statistical analyses are conducted between rock mass properties and roadheader performance to find whether there is a significant relationship between input variables and roadheader performance. The results show that rock mass properties have a considerable impact on the rate of the roadheader performance. It is demonstrated that the proposed model can accurately predict the roadheader performance as a function of rock mass properties.展开更多
评判性思维,也译为批判性思维,由20世纪30年代德国法兰克福学派学者提出[1]。1989年美国护理联盟（National League for Nursing）在护理本科的认证指南中将评判性思维能力作为衡量护理教育水平的一项重要指标。评判性思维是要求学生运...评判性思维,也译为批判性思维,由20世纪30年代德国法兰克福学派学者提出[1]。1989年美国护理联盟（National League for Nursing）在护理本科的认证指南中将评判性思维能力作为衡量护理教育水平的一项重要指标。评判性思维是要求学生运用已学知识和经验选择问题的解决方法。从护理角度看,评判性思维是指对临床复杂护理问题所进行的有目的、展开更多
The longwall mining method is often affected by the out-of-seam dilution （OSD）. Therefore, predicting and controlling of dilution are important factors for reducing mining costs. In this study, the fuzzy set theory ...The longwall mining method is often affected by the out-of-seam dilution （OSD）. Therefore, predicting and controlling of dilution are important factors for reducing mining costs. In this study, the fuzzy set theory and multiple regression models with parameters, including variation in seam thickness, dip of seam, seam thickness, depth of seam, and hydraulic radius as inputs to the models were applied to pre- dict the OSD in the longwall coal panels. Field data obtained from Kerman and Tabas coal mines, lran were used to develop and validate the models. Three indices including coefficient of determination （R2）, root mean square error （RMSE） and variance account for （VAF） were used to evaluate the perfor- mance of the models. With 10 randomly selected datasets, for the linear, polynomial, power, exponential, and fuzzy logic models, R2, RSME and VAF are equal to （0.85, 4.4, 84.4）, （0.61, 7.5, 59.6）, （0.84, 4.5, 72.7）, （0.80, 4.1, 79.6）, and （0.97, 2.1, 95.7）, respectively. The obtained results indicate that the fuzzy logic model predictor with R2 = 0.97, RMSE = 2.1, and VAF = 95.7 performs better than the other models.展开更多
文摘Peat forming environment strongly influences the economic value of any coal seam and coal-bearing strata.Hence,pal-aeoenvironmental studies provide important information for coal resource exploration.In this context,detailed studies on selected coals from the Parvadeh Area,Iran,were conducted using sedimentology,coal petrology,X-ray diffraction(XRD),scanning electron microscopy-energy dispersive X-ray analyzer(SEM-EDX),and proximate analysis.The sedi-mentary facies above and below the coal seams are mainly marine or marine-influenced facies,supporting that the coal-forming mires in the Parvadeh Area developed in a paralic environment,where the base level must be closely related to sea level.Sulfur contents are moderate to high and mark the influence of brackish/marine water,especially during transgres-sion after peat growth in a lower delta plain environment.The peat-forming mires extended on coastal/delta plain lobes.The lower delta plain/coastal plain coals are characterized by lateral continuity and substantial thickness,whereas few coals possibly representing the upper delta plain are thin and more discontinuous.The detrital nature and composition of the numerous partings and the overall high ash yield in the coal seams indicate an active tectonic area with high rates of creation of accommodation space over peat growth.Coal petrology and coal facies analysis exhibits a permanently high water table within a forest swamp and mostly rheotrophic conditions,sometimes with connection to the seawater.Accord-ing to paleoenvironmental reconstructions,it seems that coal layers may be thicker,with less sulfur(pyrite),but more clastic minerals and partings toward the western part of the area.Although these coal seams presently have low economic potential for the mining operation,partly due to great depth,this humic,high-volatile to medium-volatile bituminous coal may be suitable for exploration of coal bed methane resources.
文摘In this research, Tabas area, which is located in central Iran, was selected as the study area and three geomorphic indices were calculated for its structural fronts. Through averaging these three indices, we obtained index of active tectonics (IAT). The values of the index were divided into classes to define the degree of active tectonics. Therefore, relative tectonic activity was calculated and their values were classified and analyzed in two groups. Regions were identified as high and moderate levels. In analyzing data and combining them with tectonic setting, the results were often associated and justified with regional geology. Our results show that the highest value is located along Shoutori fault, which shows 2 class of relative tectonic activity (high level). Also, moderate values are located along Ereshk, Ezmeighan and Jamal faults (moderate level). According to these results, Shoutori fault is the most active fault in the study area and this situation is compatible with its position as a mountain front fault.
基金The exploration directorate of NIOC provided the data.The Petroleum Geology and Geochemistry Research Center(PGGRC)at Shahid Chamran University of Ahvaz provided laboratory services for conducting organic petrographic studies.
文摘This paper presents organic geochemical evidence pointing to the occurrence of wildfire events at the Triassic-Jurassic boundary in Central Iran.The studied outcrop section(the Kamarmacheh Kuh section)is comprised of the Upper Triassic Nayband Formation which passes conformably into the Lower Jurassic Ab-e-Haji Formation with no sharp boundary.Organic petrographical studies reveal a higher concentration of semi-fusinite macerals and microscopic charcoal at the boundary between studied formations.This observation can be an evidence for widespread wildfire events at the Triassic-Jurassic boundary of the studied area.Following these fires,vast areas of land were exposed for erosion and large volumes of clastic sediments were provided due to increased run-off.This agrees well with previous sedimentological and stratigraphical studies suggesting a major change in the depositional conditions from marine to non-marine at the Triassic-Jurassic boundary of the Tabas Basin.These findings can have important implications about paleo-depositional settings of the studied formations and the nature of the associated organic matter.
基金financial support from the International Centre for Geohazards (ICG)/ Norwegian Geotechnical Institute (NGI), Oslo, Norway for the research and field trips to Iran
文摘This article addresses three large earthquake disasters in Iran: Tabas in 1978, Rudbar in 1990, and Bam in 2003. Lessons and 'Lessons Learned' from these three earthquake disasters were investigated together with their contributions over time towards earthquake disaster risk reduction in Iran. Many lessons from 1978 Tabas, 1990 Rudbar, and 2003 Bam did not become 'Lessons Learned' and they were identified again within the dramatic context of other earthquake disasters in various places of Iran. Both lessons and 'Lessons Learned' from Tabas, Rudbar, Bam,and other earthquake disasters in Iran require a sustainable long-term framework—an earthquake culture.
文摘A pplication o f m echanical excavators is one o f th e m o st com m only used excavation m eth o d s because itcan bring th e p ro ject m ore productivity, accuracy and safety. A m ong th e m echanical excavators, roadhead ers are m echanical m iners w h ich have b een extensively u se d in tu n n elin g , m ining an d civil indu stries. Perform ance pred ictio n is an im p o rta n t issue for successful ro a d h e a d e r application andgenerally deals w ith m achine selection, p ro d u ctio n rate an d b it consu m p tio n . The m ain aim o f thisresearch is to investigate th e c u ttin g p erfo rm an ce （in stan tan eo u s c u ttin g rates （ICRs）） o f m ed iu m -d u tyro ad h ead ers by using artificial neural n etw o rk （ANN） approach. T here are d ifferent categories forANNs, b u t based o n train in g alg o rith m th e re are tw o m ain k in d s： supervised and u n su p erv ised . Them u lti-lay er p ercep tro n （MLP） an d K ohonen self-organizing feature m ap （KSOFM） are th e m o st w idelyused neu ral netw o rk s for supervised an d u n su p erv ised ones, respectively. For gaining this goal, ad atab ase w as prim arily provided from ro ad h e a d e rs＇ p erfo rm an ce an d geom echanical characteristics o frock form ations in tu n n els and d rift galleries in Tabas coal m ine, th e larg est an d th e only fullymech an ized coal m ine in Iran. T hen th e datab ase w as analyzed in o rd e r to yield th e m ost im p o rtan tfactor for ICR by using relatively im p o rta n t factor in w hich G arson eq u atio n w as utilized. The MLPn etw o rk w as train ed by 3 in p u t p ara m e te rs including rock m ass pro p erties, rock quality d esignation（RQD）, in tact rock p ro p erties such as uniaxial com pressive stre n g th （UCS） an d Brazilian ten sile stren g th（BTS）, and o n e o u tp u t p a ra m e te r （ICR）. In o rd e r to have m ore v alidation o n MLP o u tp u ts, KSOFM visualizationw as applied. The m ean square e rro r （MSE） an d regression coefficient （R ） o f MLP w e re found tobe 5.49 an d 0.97, respectively. M oreover, KSOFM n etw o rk has a m ap size o f 8 x 5 and final qu an tizatio nan d topographic erro rs w e re 0.383 an d 0.032, respectively. The results show th a t MLP neural n etw orkshave a strong capability to p red ict an d ev alu ate th e perfo rm an ce o f m ed iu m -d u ty ro ad h ead ers in coalm easu re rocks. Furtherm ore, it is concluded th a t KSOFM neural n etw o rk is an efficient w ay for u n d e rstand in g system beh av io r an d know ledge extraction. Finally, it is indicated th a t UCS has m ore influenceo n ICR b y applying th e b e st train ed MLP n etw o rk w eig h ts in G arson eq u atio n w h ich is also confirm ed byKSOFM.
文摘Prediction of roadheader performance plays a significant role in the plan of tunnel construction, which is influenced by different key parameters, including rock strength, discontinuity in rock mass, type and specifications of roadheader machine, and brittleness. The main aim of this study is to build a robust empirical equation based on rock mass properties for the roadheader performance prediction. For achieving the aim, a dataset composed of roadheader performance rate and rock properties is established using the dataset compiled from an underground coal mine located in a remote rugged desert environment some 85 km south of Tabas City in mid east Iran. By using gathered data, the statistical analyses are conducted between rock mass properties and roadheader performance to find whether there is a significant relationship between input variables and roadheader performance. The results show that rock mass properties have a considerable impact on the rate of the roadheader performance. It is demonstrated that the proposed model can accurately predict the roadheader performance as a function of rock mass properties.
文摘评判性思维,也译为批判性思维,由20世纪30年代德国法兰克福学派学者提出[1]。1989年美国护理联盟（National League for Nursing）在护理本科的认证指南中将评判性思维能力作为衡量护理教育水平的一项重要指标。评判性思维是要求学生运用已学知识和经验选择问题的解决方法。从护理角度看,评判性思维是指对临床复杂护理问题所进行的有目的、
文摘The longwall mining method is often affected by the out-of-seam dilution （OSD）. Therefore, predicting and controlling of dilution are important factors for reducing mining costs. In this study, the fuzzy set theory and multiple regression models with parameters, including variation in seam thickness, dip of seam, seam thickness, depth of seam, and hydraulic radius as inputs to the models were applied to pre- dict the OSD in the longwall coal panels. Field data obtained from Kerman and Tabas coal mines, lran were used to develop and validate the models. Three indices including coefficient of determination （R2）, root mean square error （RMSE） and variance account for （VAF） were used to evaluate the perfor- mance of the models. With 10 randomly selected datasets, for the linear, polynomial, power, exponential, and fuzzy logic models, R2, RSME and VAF are equal to （0.85, 4.4, 84.4）, （0.61, 7.5, 59.6）, （0.84, 4.5, 72.7）, （0.80, 4.1, 79.6）, and （0.97, 2.1, 95.7）, respectively. The obtained results indicate that the fuzzy logic model predictor with R2 = 0.97, RMSE = 2.1, and VAF = 95.7 performs better than the other models.
