Investigating a potential reservoir landslide and suggesting its treatment using limit-equilibrium and numerical methods

A reservoir landslide not only reduces the water storage capacity, but also causes extensive damages to the dam body, power/water transmission lines, roads, and other infrastructures. The Latian Dam, located 35 km north east of Tehran(Iran), is one of the cases which has encountered serious problems with instability of its rock abutments. This paper addresses the stability analysis of the right abutment of the Latian Dam using limit equilibrium and numerical methods. Geomechanical characteristics of the rock abutment were first estimated based on engineering classification of the rock mass. Different search methods were examined for locating the critical circular/non-circular slip surface in conjunction with the general limit equilibrium method. The effect of variability of rock mass properties, water table, and earthquake load on the factor of safety(FS) and probability of failure(PF) was studied. In the event of rapid drawdown in the reservoir, the limit equilibrium analysis calculated FS=1.067 and PF=21.1%, and the numerical analysis returned FS=1.01. The results of the analyses suggest that the right abutment of the Latian Dam is prone to slide and needs treatment. Investigations demonstrated that a slope reduction by 15? at the upper part of the abutment would meet stability conditions even in the worst-case scenario(FS=1.297 and PF=2.07%).

Evaluation of plow system performance in long-wall mining method using particle flow code

The underground or open-pit methods are used for the extraction of mineral resources,each of which is divided into different categories.Coal is one of the mineral resources,which is exploited either by the surface or the underground methods.The long-wall mining is one of the methods for the underground coal mining.In this method,which is a mechanized one,some machines such as the shearer or plow are used for the mining.The coal mine in Parvadeh,Tabas is a mechanized mine that is extracted by the long-wall mining.The modeling with particle flow code software was used in this mine for the evaluation of plow performance using the coal specifications.In this regard,the sample was first calibrated by sampling from the Parvadeh coal mine and performing the uniaxial and Brazilian tests on the model.Then,the modeling was done by constructing the model and using the variables such as the clearance angle and the linear velocity of the plow.After making 28 models for the plow,the best model of the plow was selected based on the maximum force applied to the machine in the X direction.Finally,the results of this study showed that the best plow performance is for a model with the clearance angle of zero and the linear velocity of 9 mm/min,and the maximum force applied to this model is equal to 39,000 kN in the X direction.

Down-regulation of Halr1 during induced differentiation of embryonal carcinoma P19 cells

Maintenance of pluripotency depends to diverse regulatory factors.Studies in embryonic stem cells(ESCs)have indicated that large intergenic non-coding RNAs(lincRNAs)are involved in the regulatory network of pluripotency.However,the presence and function of pluripotency-associated lincRNAs in cancer cells with pluripotency features are unknown.In this study,we used embryonal carcinoma(EC)P19 cell lines to investigate the expression level of Halr1 in pluripotency and retinoic acid(RA)-induced differentiated states.Down-regulation of pluripotency associated factors such as OCT4,NANOG,SSEA1 and alkaline phosphatase at transcript and protein levels were used to confirm the differentiated status of P19 cells.Quantitative measurement of Halr1 transcript levels revealed a 79% decrease during RA-induced differentiation of P19 cells.These results indicate that upon exiting the pluripotency state the expression level of Halr1 similar to core pluripotency factors is remarkably reduced.