Mechanical behaviors of deep pillar sandwiched between strong and weak layers

A variety of coal room and pillar mining methods have been efficiently practiced at depths of up to 500 m with least strata mechanics issues.However,for the first time,this method was trialled at depths of 850 e900 m in CSM mine of Czech Republic.The rhomboid-shaped coal pillars with acute corners of 70,surrounded with 5.2 m wide and 3.5e4.5 m high mine roadways,were used.Pillars were developed in a staggered manner with their size variation in the Panel II from 83 m×25 m to 24 m×20 m(corner to corner)and Panel V from 35 m×30 m to 26 m×16 m.Coal seam inclined at 12was affected by the unusual slippery slickenside roof bands and sometimes in the floor levels with high vertical stress below strong and massive sandstone roof.In order to ensure safety,pillars in both the panels were continuously monitored using various geotechnical instruments measuring the induced stresses,side spalling and roof sagging.Both panels suffered high amounts of mining induced stress and pillar failure with side-spalling up to 5 m from all sides.Heavy fracturing of coal pillar sides was controlled by fully encapsulated steel bolts.Mining induced stress kept increasing with the progress of development of pillars and galleries.Instruments installed in the pillar failed to monitor actual induced stress due to fracturing of coal mass around it which created an apprehension of pillar failure up to its core due to high vertical mining induced stress.This risk was reduced by carrying out scientific studies including the three-dimensional numerical models calibrated with data from the instrumented pillar.An attempt has been made to study the behavior of coal pillars and their yielding characteristics at deeper cover based on field and simulation results.

Effect of Inclined Tension Crack on Rock Slope Stability by SSR Technique

The tension cracks and joints in rock or soil slopes affect their failure stability.Prediction of rock or soil slope failure is one of the most challenging tasks in the earth sciences.The actual slopes consist of inhomogeneous materials,complex morphology,and erratic joints.Most studies concerning the failure of rock slopes primarily focused on determining Factor of Safety(FoS)and Critical Slip Surface(CSS).In this article,the effect of inclined tension crack on a rock slope failure is studied numerically with Shear Strength Reduction Factor(SRF)method.An inclined Tension Crack(TC)influences the magnitude and location of the rock slope’s Critical Shear Strength Reduction Factor(CSRF).Certainly,inclined cracks are more prone to cause the failure of the slope than the vertical TC.Yet,all tension cracks do not lead to failure of the slope mass.The effect of the crest distance of the tension crack is also investigated.The numerical results do not show any significant change in the magnitude of CSRF unless the tip of the TC is very near to the crest of the slope.ATC is also replaced with a joint,and the results differ from the corresponding TC.These results are discussed regarding shear stress and Critical Slip Surface(CSS).

Robust Optimal H∞ Control for Uncertain 2-D Discrete State-Delayed Systems Described by the General Model

This paper investigates the problem of robust optimal H∞ control for uncertain two-dimensional (2-D) discrete state-delayed systems described by the general model (GM) with norm-bounded uncertainties. A sufficient condition for the existence of g-suboptimal robust H∞ state feedback controllers is established, based on linear matrix inequality (LMI) approach. Moreover, a convex optimization problem is developed to design a robust optimal state feedback controller which minimizes the H∞ noise attenuation level of the resulting closed-loop system. Finally, two illustrative examples are given to demonstrate the effectiveness of the proposed method.

Delay-Dependent Robust H∞ Control for Uncertain 2-D Discrete State Delay Systems Described by the General Model

This paper considers the problem of delay-dependent robust optimal H∞ control for a class of uncertain two-dimensional (2-D) discrete state delay systems described by the general model (GM). The parameter uncertainties are assumed to be norm-bounded. A linear matrix inequality (LMI)-based sufficient condition for the existence of delay-dependent g-suboptimal state feedback robust H∞ controllers which guarantees not only the asymptotic stability of the closed-loop system, but also the H∞ noise attenuation g over all admissible parameter uncertainties is established. Furthermore, a convex optimization problem is formulated to design a delay-dependent state feedback robust optimal H∞ controller which minimizes the H∞ noise attenuation g of the closed-loop system. Finally, an illustrative example is provided to demonstrate the effectiveness of the proposed method.

Transient Stability Improvement of Power System Using Non-Linear Controllers

This paper presents the design of a non-linear controller to prevent an electric power system losing synchronism after a large sudden fault and to achieve good post fault voltage level. By Direct Feedback Linearization (DFL) technique robust non-linear excitation controller is designed which will achieve stability enhancement and voltage regulation of power system. By utilizing this technique, there is a possibility of selecting various control loops for a particular application problem. This method plays an important role in control system and power system engineering problem where all relevant variables cannot be directly measured. Simulated results carried out on a single machine infinite bus power system model which shows the enhancement of transient stability regardless of the fault and changes in network parameters.

Fabrication, characterization, numerical simulation and compact modeling of P3HT based organic thin film transistors

This paper presents the fabrication,characterization and numerical simulation of poly-3-hexylthiophene(P3HT)-based bottom-gate bottom-contact(BGBC)organic thin film transistors(OTFTs).The simulation is based on a drift diffusion charge transport model and density of defect states(DOS)for the traps in the band gap of the P3HT based channel.It combines two mobility models,a hopping mobility model and the Poole-Frenkel mobility model.It also describes the defect density of states(DOS)for both tail and deep states.The model takes into account all the operating regions of the OTFT and includes sub-threshold and above threshold characteristics of OTFTs.The model has been verified by comparing the numerically simulated results with the experimental results.This model is also used to simulate different structure in four configurations of OTFT e.g.bottom-gate bottom-contact(BGBC),bottom-gate top-contact(BGTC),top-gate bottom-contact(TGBC)and top-gate top-contact(TGTC)configurations of the OTFTs.We also present the compact modeling and model parameter extraction of the P3HT-based OTFTs.The extracted compact model has been further applied in a p-channel OTFT-based inverter and three stage ring oscillator circuit simulation.

Channel estimation and channel tracking for correlated block-fading channels in massive MIMO systems

This paper presents a channel estimation and tracking method for correlated block-fading channels in massive MIMO wireless cellular systems. In order to conserve resources, the proposed algorithm requires the uplink pilot signal only once, at the start of communication. By utilizing the temporal correlation between consecutive Resource Blocks （RBs） and the error correction capability of turbo codes, the channel matrix in subsequent RBs is estimated at the Base Station （BS） itself using the uplink data of current the RB and the estimated channel matrix of previous the RB. Compared to existing blind estimation methods, the proposed method places fewer limitations on the system settings such as the number of BS antennas, the number of users, and the number of coherent channel usage compared to existing blind estimation methods. Simulation results show that the proposed algorithm provides better performance for a moderate RB size, a high-order of QAM scheme, and a smaller ratio of the number of BS antennas and mobile terminals （N/K）. For a reasonably small N/K （order of 10）, the proposed scheme achieves a lower symbol error probability than the conventional pilot-based estimation approach.

Effect of Heat Source/Sink on Free Convective Flow of a Polar Fluid between Vertical Concentric Annuli

The purpose of this paper is to find the effect of heat source/sink parameter on free convective flow of a polar fluid in open-ended vertical concentric annuli. Exact solutions of the non-dimensional differential equations describing the flow model have been obtained one by one for two different cases of source and sink. To observe the effect of the physical parameters such as source/sink and vertex viscosity, the numerical results of the velocity and microrotational velocity are finally shown on the graphs.

Blockchain Based Secure Solution for Cloud Storage:A Model for Synchronizing Industry 4.0 and IIoT

Industry 4.0 is one of the hot topic of today’s world where everything in the industry will be data driven and technological advancements will take place accordingly.In the fourth phase of industrial revolution,manufacturers are dependent upon data produced by the consumers to invent,innovate or change anything for the product.Internet of things devices like OBD,RFID,IIoT,Smart devices are the major source of data generation and represents trends in the industry.Since the IoT device are vulnerable to hackers due to its limitation,consumer data security should be tighten up and enhanced.This paper gives an overview of industrial revolutions as well as proposes Blockchain Cloud Computing as a solution to store data for Industry 4.0.

Clodronate-superparamagnetic iron oxide-containing liposomes attenuate renal injury in rats with severe acute pancreatitis

Background and objective： It has been shown that macrophages play an important role in the development of severe acute pancreatitis （SAP）, and eventually lead to multiple organ failure （MOF）. Clodronate-liposome selectively depleted macrophages. This study was to investigate the role of renal macrophage infiltration in acute renal injury in rats with SAP and to evaluate the potential of superparamagnetic iron oxide （SPIO）-enhanced magnetic resonance imaging （MRI） for diagnosis. Methods： Superparamagnetic Fe3O4 nanoparticles were prepared by chemical coprecipitation. SPIO-liposomes and SPIO-clodronate-liposomes were prepared by the thin film method. SAP models were prepared by injection of sodium taurocholate into the subcapsular space of rat pancreas. Sprague-Dawley rats were randomly divided into a control group, SAP plus SPIO-liposome （P） group, and SAP plus SPIO-clodronatecontaining liposome （T） group. Kidney injury was evaluated by T2-weighted MRI scan. The levels of serum amylase （SAM）, blood urea nitrogen （BUN）, and serum creatinine （SCr） were measured by an automated enzymatic method. Serum tumor necrosis factor-α （TNF-α） was measured by enzyme-linked immunosorbent assay （ELISA）. Pathological changes in the pancreas and kidney were observed using hematoxylin and eosin （H＆E） staining, while cell apoptosis was detected with terminal deoxynucleotidyl transferase dUTP nick end labeling （TUNEL） staining. In addition, the macrophage markers （CD68） of the renal tissue were detected with immunohistochemistry. Results： The pathological changes in the pancreas and kidneys of rats in the T group were milder than those in the P group. The MRI signal intensity of the kidneys in the P and T groups was significantly lower than that in the control group. There were significant changes in the two experimental groups （P〈0.01）. The levels of SAM, Bun, SCr, and TNF-α in rats in the P group were higher than those in the control group （P〈0.01） and in the T group （P〈0.01）. The apoptosis of the kidney in the T group was higher than that in the P group at 2 and 6 h （P〈0.01）. Conclusions： Clodronate-containing liposomes protected against renal injury in SAP rats, and SPIO can be used as a tracer for MRI examination to detect renal injury in SAP rats. SPIO-aided MRI provided an efficient non-invasive way to monitor the migration of macrophages after renal injury in rats with SAP.

Design of a 2-DOF-PID controller using an improved sine-cosine algorithm for load frequency control of a three-area system with nonlinearities

This paper proposes an improved sine-cosine algorithm(ISCA)based 2-DOF-PID controller for load frequency control.A three-area test system is built for study,while some physical constraints(nonlinearities)are considered for the investigation of a realistic power system.The proposed method is used as the parameter optimizer of the LFC control-ler in different scenarios.The 2-DOF-PID controllers are used because of their capability of fast disturbance rejection without significant increase of overshoot in set-point tracking.The 2-DOF-PID controllers’efficacy is observed by examining the responses with the outcomes obtained with PID and FOPID controllers.The simulation results with the suggested scheme are correlated with some of the existing algorithms,such as SCA,SSA,ALO,and PSO in three dif-ferent scenarios,i.e.,a disturbance in two areas,in three areas,and in the presence of physical constraints.In addition,the study is extended to a four-area power system.Statistical analysis is performed using the Wilcoxon Sign Rank Test(WSRT)on 20 independent runs.This confirms the supremacy of the proposed method.