Finite difference modelling in underground coal mine roadway

This paper presents stability analysis of roadways of the Tabas coal mine in Iran. Tabas Coal Mine is the first fully mechanised coal mine in Iran, producing 1.5 million tons of coal per year. The mine extracts coal by both longwall and room and pillar methods. The results gathered from field investigations and the geomechanical properties of rocks, were determined in the laboratory and indicate that the rock masses of this area are weak. So, the excavated roadways need to have suitable support. For this purpose, the roadways were modeled with FLAC-2D software. The Finite Difference Method (FDM) models were calibrated to study the interaction between rock mass and support. The use of V29 and V36 section arches are under consideration. After modelling these roadways in FLAC2D software the results achieved from this model show that; displacements of around the roadways are high and safety factors are very low, so roadways need to be support. The extracted results from this software show that; steel arch V36 with a spacing of 1m is the best support system for these roadways. With this type of support system, displacements around the roadway are low and safety factors are in suitable values. After installation it was observed that the critical strain values on roadway walls and roof were less than the permitted values, which demonstrated the roadway stability

In vitro evaluation of the effect of ethanolic extract of Propolis on human hemoglobin glycation, a laboratory study

زمینه و هدف: گلایکه شدن واکنش غیر آنزیمی اتصال قند به پروتئین می باشد که در افراد دیابتی با میزان قند ‌خون بالا، افزایش می یابد. محصولات تولید شده در این واکنش باعث ایجاد و تشدید عوارض دیابت می شوند و نیز در بسیاری از بیماری ها دخیل هستند. پروپولیس (Propolis) از گذشته‌های دور به‌ طور گسترده ای در طب سنتی به ‌کار برده می شود و شواهد قابل توجهی وجود دارد که نشان می دهد پروپولیس دارای خاصیت آنتی‌اکسیدانی بسیار قوی می‌باشد. این مطالعه با هدف بررسی اثر پروپولیس در کاهش میزان گلایکه شدن هموگلوبین در شرایط آزمایشگاهی انجام شده است. روش بررسی: در این مطالعه تجربی، هموگلوبین تخلیص شده در حضور و عدم حضور قند گلوکز و عصاره اتانولی پروپولیس با سه غلظت مختلف به مدت 5 هفته انکوبه گردید. میزان گلایکه شدن هموگلوبین به وسیله سنجش میزان آزاد سازی گروه هِم موجود در هموگلوبین و جابجایی باند سورت، تولید محصولات ناشی از تخریب هِم و بررسی ساختارهای آمیلوئیدی به ‌کمک طیف ‌سنجی مرئی- ماوراء بنفش و فلوئورسانس تعیین شد. همچنین از آسپیرین به عنوان ماده ضدگلایکه‌ی کنترل استفاده شد. یافته ها: گلایکه شدن هموگلوبین در حضور عصاره پروپولیس با بالاترین غلظت به میزان 50 درصد مهار گردید. دو غلظت کمتر عصاره میزان مهار پایین تری از گلایکه شدن نشان داد. همچنین بررسی های انجام‌ شده در مورد محصولات ناشی از تخریب هِم و ساختار فیبریلار، نشان دهنده کاهش چشمگیر گلایکه شدن هموگلوبین در حضور عصاره پروپولیس می باشد. نتیجه گیری: هموگلوبین در حضور گلوکز به شدت گلایکه شد و پروپولیس در یک روند وابسته به غلظت از این واکنش جلوگیری کرده و گلایکه ‌شدن هموگلوبین را کاهش داد. احتمالاً پروپولیس به ‌وسیله‌ی خاصیت آنتی ‌اکسیدانی قوی خود گلایکه شدن پروتئین را مهار می نماید و از‌این‌رو می تواند در کاهش عوارض دیابت موثر باشد

Development of a wireless system to measure the strain/deformation of rock bolts

In this study a smart set-up integrated with rock bolts was proposed to automatically monitor, record and analyse rock mass deformation. The proposed system which includes sensors and a wireless data acquisition system, rapidly and readily generates data sets along with customisable graphs, calculations and analysis in a cloud system and can be used in modern mining. To evaluate the developed technique, rock bolts were instrumented lengthwise using resistive strain gauges and then connected to the wireless data logger system. Elastic tensile tests as well as pull-out tests were conducted and the strain values along the rock bolts were successfully and accurately measured, recorded and uploaded to the cloud system

Finite element numerical modelling of rock bolt axial behaviour subject to different geotechnical conditions

In rock bolting systems, grout acts as a medium to transfer initiated stress from the bolt to stable rock mass, and also to transfer the in-situ stress from surrounding rock to the bolt-grout interface. In this study interaction between the mechanical characteristics of the grout and rock bolt behaviour was investigated in different confining pressure conditions. First, the uniaxial compression strength of the grouts was experimentally determined, and then pull-out tests were carried out on rock bolts encapsulated using the same grouts to quantify the bonding behaviour. Numerical models using ABAQUS explicit finite element code were then applied to further analyse the effects of mechanical properties of the grouts and the confining stress on the behaviour of the rock bolting systems. The compression of the simulated results with the experimental tests showed that the proposed FE models simulate the axial behaviour of rock bolts efficiently. The results of the parametric study indicated that grout mechanical properties and the level of confining stress affect the ultimate bearing capacity of the encapsulated rock bolts and the force-displacement behaviour. The level of damage that occurred at the specimens due to pull-out load is also significantly influenced by these factors

Prediction of Rock Mass Rating using Fuzzy Logic with Special Attention to Discontinuities and Ground Water Conditions

The Rock Mass Rating (RMR) system is a classification based on the six parameters which was defined by Bieniawski. This system may possess some fuzziness in its practical applications. For example, experts mostly relate discontinuities and ground water conditions in linguistic terms with approximation. Descriptive terms vary from one expert to the other, while in the RMR system; values which are related to these terms are probably the same. The other hand, sharp transitions between two classes create uncertainties. So it is proposed to determine weighting intervals for discontinuities and water condition. Two fuzzy models based on the Mamdani algorithm were introduced to evaluate proposed weights, so that the first fuzzy model includes 55 scores using fuzzy model and the remained scores which are related to discontinuities and ground water conditions are obtainable by the RMR system. But the second fuzzy model obtains all scores of the RMR system using fuzzy model. Results of fuzzy models are adapted with actual RMR, but second fuzzy model predicts more acceptable results, because it has the ability to use qualitative terms in fuzzy state. But first fuzzy model uses descriptive terms in classic state. So it seems, proposed weighting intervals can manage fuzzification of discontinuities and water conditions

Development of a wireless system to measure the strain/deformation of rock bolts

In this study a smart set-up integrated with rock bolts was proposed to automatically monitor, record and analyse rock mass deformation. The proposed system which includes sensors and a wireless data acquisition system, rapidly and readily generates data sets along with customisable graphs, calculations and analysis in a cloud system and can be used in modern mining. To evaluate the developed technique, rock bolts were instrumented lengthwise using resistive strain gauges and then connected to the wireless data logger system. Elastic tensile tests as well as pull-out tests were conducted and the strain values along the rock bolts were successfully and accurately measured, recorded and uploaded to the cloud system

Genetic Variations of Tumor Necrosis Factor –α-308 and Lymphtoxin-α+252 in Non-Hodgkin Lymphoma and Acute Lymphoblastic Leukemia Patients

Objective(s): Non- Hodgkin lymphoma (NHL) and acute lymphoblastic leukemia (ALL) are two main hematological malignances which have been driven from lymphoid tissue. Genetic polymorphisms in tumor necrosis factor-α (TNF-α) -308 and lymphotoxin-α (LT-α) +252 may affect their transcription and expression which leads to their high plasma level. The frequency of the TNF-α (-308) and LT-α (+ 252) polymorphisms are different for NHL and ALL cases in various populations with different ethnicity. This research is designed to investigate the prevalence and association of TNF-α (-308) and LT-α (+ 252) polymorphisms from NHL and ALL in Azarian patients and healthy individuals from Northwestern part of Iran.   Materials and Methods: Seventy subjects with ALL and 68 NHL, along with another 130 healthy subjects as control group took part in this study. Genomic DNA was extracted, then genetic polymorphisms in TNF-α and LT-α genes were analyzed with the PCR-RFLP and NCOI as restriction enzyme. A statistical analysis was performed by chi-square test using SPSS software. A P-value o