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Laboratory scale studies on removal of chromium from industrial wastes

Journal of Environmental Sciences 2003年第3期15卷 417-422页

作者： M.A.Baig mohsin mir Shazad Murtaza Zafar I. Bhatti Institute of Environmental Science & Engineering National University of Science & EngineeringInstitute of Environmental Science & Engineering National University of Science & EngineeringInstitute of Environmental Science & Engineering National University of Science & EngineeringInstitute of Environmental Science & Engineering National University of Science & Engineering Rawalpindi PakistanRawalpindi PakistanRawalpindi PakistanRawalpindi Pakistan

Chromium being one of the major toxic pollutants is discharged from electroplating and chrome tanning processes and is also found in the effluents of dyes, paint pigments, manufacturing units etc. Chromium exists in aqueous systems in both trivalent (Cr 3+) and hexavalent (Cr 6+) forms. The hexavalent form is carcinogenic and toxic to aquatic life, whereas Cr 3+ is however comparatively less toxic. This study was undertaken to investigate the total chromium removal from industrial effluents by chemical means in order to achieve the Pakistan NEQS level of 1 mg/L by the methods of reduction and precipitation. The study was conducted in four phases. In phase Ⅰ, the optimum pH and cost effective reducing agent among the four popular commercial chemicals was selected. As a result, pH of 2 was found to be most suitable and sodium meta bisulfate was found to be the most cost effective reducing agent respectively. Phase Ⅱ showed that lower dose of sodium meta bisulfate was sufficient to obtain 100 % efficiency in reducing Cr 6+ to Cr 3+, and it was noted that reaction time had no significance in the whole process. A design curve for reduction process was established which can act as a tool for treatment of industrial effluents. Phase Ⅲ studies indicated the best pH was 8.5 for precipitation of Cr 3+ to chromium hydroxide by using lime. An efficiency of 100 % was achievable and a settling time of 30 minutes produced clear effluent. Finally in Phase Ⅳ actual waste samples from chrome tanning and electroplating industries, when precipitated at pH of 12 gave 100 % efficiency at a settling time of 30 minutes and confirmed that chemical means of reduction and precipitation is a feasible and viable solution for treating chromium wastes from industries.

关键词： tannery waste effluents reduction precipitation efficiency chromium

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Is intra-operative cholangiography necessary during laparoscopic cholecystectomy? A multicentre rural experience from a developing world country

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World Journal of Gastroenterology 2007年第33期13卷 4493-4497页

作者： Iqbal Saleem mir mir mohsin Omar Kirmani Tafazul Majid Khurshid Wani Mehmood-ul Hassan Javed Naqshbandi Mohammed Maqbool Minimal Access Surgery Unit Government Gousia Hospital Khanyar Kashmir 190010 India Department of Radiology Government Gousia Hospital Khanyar Kashmir 190010 India Anaesthesia Unit Government Gousia Hospital Khanyar Kashmir 190010 India

AIM: To evaluate the feasibility and safety of performing laparoscopic cholecystectomy (LC) in nonteaching rural hospitals of a developing country without intra-operative cholangiography (IOC). To evaluate the possibility of reduction of costs and hospital stay for patients undergoing ***: A prospective analysis of patients with symptomatic benign diseases of gall bladder undergoing LC in three non-teaching rural hospitals of Kashmir Valley from Jan 2001 to Jan 2007. The cohort represented a sample of patients requiring LC, aged 13 to 78 (mean 47.2) years. Main outcome parameters included mortality, complications, re-operation, conversion to open procedure without resorting to IOC, reduction in costs borne by the hospital, and the duration of hospital ***: Twelve hundred and sixty-seven patients (976 females/291 males) underwent laparoscopic cholecystectomy. Twenty-three cases were converted to open procedures; 12 patients developed port site infection, nobody died because of the procedure. One patient had common bile duct (CBD) injury, 4 patients had biliary leak, and 4 patients had subcutaneous emphysema. One cholecystohepatic duct was detected and managed intraoperatively, 1 patient had retained CBD stones, while 1 patient had retained cystic duct stones. Incidental gallbladder malignancy was detected in 2 cases. No long-term complications were detected up to ***: LC can be performed safely even in non-teaching rural hospitals of a developing country provided proper equipment is available and the surgeons and other team members are well trained in the procedure. It is stressed that IOC is not essential to prevent biliary tract injuries and missed CBD stones. The costs to the patient and the hospital can be minimized by using reusable instruments, intracorporeal sutures, and condoms instead of titanium clips and endobags.

关键词： Laparoscopic cholecystectomy Intraoperative cholangiography

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Simulation of the Galactic Cosmic Ray Shadow of the Sun

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Chinese Physics Letters 2017年第12期34卷 79-83页

作者： mohsin Saeed 查敏曹臻 Key Laboratory of Particle Astrophysics Institute of High Energy PhysicsChinese Academy of Sciences University of Chinese Academy of Sciences State Key Laboratory of Space Weather Chinese Academy of Sciences

The cosmic-ray particles of TeV-regime, outside the solar system are blocked in their way to the Earth, a deficit of particles is observed corresponding to the location of the Sun known as the Sun shadow. The center of the Sun shadow is shifted from its nominal position due to the presence of magnetic fields in interplanetary space,and this shift is used indirectly as a probe to study the solar magnetic field that is difficult to measure otherwise.A detailed Monte Carlo simulation of galactic cosmic-ray propagation in the Earth-Sun system is carried out to disentangle the cumulative effects of solar, interplanetary and geomagnetic fields. The shadowing effects and the displacements results of the Sun shadow in different solar activities are reproduced and discussed.

关键词： Simulation of the Galactic Cosmic Ray Shadow of the Sun LHAASO IMF

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Three-dimensional computational fluid dynamics （volume of fluid） modelling coupled with a stochastic discrete phase model for the performance analysis of an invert trap experimentally validated using field sewer solids

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Particuology 2017年第4期15卷 98-111页

作者： Mohammad mohsin Deo Raj Kaushal Civil Engineering Department Indian Institute of Technology Delhi New Delhi India

Invert traps are used to trap sewer solids flowing into a sewer drainage system, The performance of the invert trap in an open rectangular channel was experimentally and numerically analysed using field sewer solids collected from a sewer drain. Experiments showed that the free water surface rises over the central opening （slot） of the invert trap, which reduces the velocity near the slot and allows more sediment to be trapped in comparison with the case for the fixed-lid model （assuming closed conduit flow with a shear-free top wall） used by earlier investigators. This phenomenon cannot be modelled using a closed conduit model as no extra space is provided for the fluctuation of the water surface, whereas this space is provided in the volume of fluid （VOF） model in the form of air space in ANSYS Fluent 14.0 software. Additionally, the zero atmospheric pressure at the free water surface cannot be modelled in a fixed-lid model. In the present study, experimental trap efflciencies of the invert trap using field sewer solids were fairly validated using a three-dimensional computational fluid dynamics model （VOF model） coupled with a stochastic discrete phase model. The flow field （i.e., velocities） predicted by the VOF model were compared with experimental velocities obtained employing particle image velocimetry. The water surface profile above the invert trap predicted by the VOF model was found to be in good agreement with the experimentally measured profile. The present study thus showed that the VOF model can be used with the stochastic discrete phase model to well predict the performance of invert traps.

关键词： Computational fluid dynamics mode Invert trap Sedimentation Trap efficiency Retention ratio Volume of fluid model

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Deformation Kinematics of Main Central Thrust Zone(MCTZ)in the Western Himalayas

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Journal of Earth Science 2022年第2期33卷 452-461页

作者： mohsin Ahmad Ahanger Ghulam Jeelani Department of Earth Sciences University of KashmirSrinagar 190006India

The main central thrust(MCT)is one of the major thrusts in *** central Himalaya,MCT was defined as a contact between underlying Lesser Himalayan Sequence(LHS)and overlying higher Himalayan crystallines(HHC).However,in the Kashmir Himalayas,the main central thrust zone(MCTZ),shear zone associated with MCT,is overlain by Kashmir Tethyan Sequence suggesting that the MCTZ has been deformed through a mechanism different than the mechanism responsible for MCTZ evolution in other parts of the *** the present study we used structural,microfabric and kinematic analyses to investigate the deformation kinematics of *** investigation revealed that the quartz in orthogneiss mylonites of MCTZ was dynamically recrystallized by grain boundary migration(GBM)and sub-grain rotation recrystallisation(SGR)with top-toSW sense of *** mean kinematic vorticity number(W;)just above the thrust ranges from 0.72to 0.84(40%–52%pure shear component)decreasing upwards to 0.65–0.71(35%–50%pure shear component).Deformation in the MCTZ is characterized by Rxzstrain ratio varying from 2.7 to *** present study suggested that the MCTZ suffered 3%–40%vertical shortening and 3%–66%transportparallel *** results suggested that the HHC’s were not completely exhumed to the topographic surfaces in the Kashmir *** the basal decollement,i.e.,the main Himalayan thrust(MHT),the deformation continued until MCTZ reached the brittle-ductile transition where deformation mechanism changed to the brittle and the MCTZ rocks were transported to the surface through slip on brittle MCT.

关键词： kinematics mylonites finite strain mean kinematic vorticity number(Wm) general shear tectonics

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Principal Component Analysis and Minimum Description Length Criterion Based on Through-Wall Image Enhancement

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Chinese Physics Letters 2013年第4期30卷 45-47页

作者： Muhammad mohsin Riaz Abdul Ghafoor Department of Electrical Engineering College of SignalsNational University of Sciences and Technology(NUST)IslamabadPakistan

A through-wall image enhancement scheme is proposed based on principal component analysis and minimum description length *** minimum description length criterion is used with principal component analysis to extract target eigen *** proposed scheme is capable of extracting multiple targets from heavy cluttered through-wall *** results of the proposed scheme are compared with existing schemes on the basis of quantitative analysis and visual inspection.

关键词： criterion. Image scheme

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Effect of Zinc additive on dielectric properties of Cd–Se glassy system

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Progress in Natural Science:Materials International 2015年第3期25卷 222-228页

作者： mohsin Ganaie M.Zulfequar Department of Physics Jamia Millia Islamia

Cd5Se95–xZnx(x=0, 2, 4, 6) glassy alloy has been prepared by a melt-quenching technique. Thin films were deposited by thermal coating unit on ultraclean glass substrate under a vacuum of 10–6Torr. The absence of any sharp peaks in the X-ray diffraction confirms the amorphous nature of thin films. The frequency and temperature dependence of dielectric constant and dielectric loss in the frequency range of 1 kHz to 1 MHz and in the temperature range of 290–370 K were studied. Dielectric dispersion was observed when Zinc(Zn) was incorporated into the Cd–Se *** increase in dielectric parameter with Zn concentration may be due to increase in defect states. The DC conductivity has been reported to investigate the effect of Zn concentration on DC conduction loss. The results are interpreted in term of dipolar theory for Cd5Se95 and Cd5Se93Zn2samples, while the remaining samples have been explained on the basis of DC conduction loss. It was also observed that the DC conductivity increased with the increase of Zinc concentration, which may be due to the decrease in the band gap near Fermi level.

关键词： Amorphous semiconductor Localized states DC conductivity Dielectric constant Dielectric loss

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3D CFD validation of invert trap efficiency for sewer solid management using VOF model

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Water Science and Engineering 2016年第2期9卷 106-114页

作者： Mohammad mohsin Deo Raj Kaushal Civil Engineering Department Indian Institute of Technology Delhi

Earlier investigators have numerically carried out performance analysis of the invert trap fitted in an open channel using the stochastic discrete phase model(DPM) by assuming the open channel flow to be closed conduit flow under pressure and assuming zero shear stress at the top *** is known as the fixed lid *** assuming the top wall to be a shear free wall,they have been able to show that the velocity distribution looks similar to that of an open channel flow with zero velocity at the bottom and maximum velocity at the top,representing the free water surface,but no information has been provided for the pressure at the free water *** of this assumption,the validation of the model in predicting the trap efficiency has performed significantly *** addition,the free water surface subject to zero gauge pressure cannot be modeled using the fixed lid model because there is no provision of extra space in the form of air space for the fluctuating part of the water surface *** ***,be modeled using the volume of fluid(VOF) model because the VOF model is the appropriate model for open channel or free surface ***,in the present study,three-dimensional(3D) computational fluid dynamics(CFD) modeling with the VOF model,which considers open channel flow with a free water surface,along with the stochastic *** used to model the trap efficiency of an invert trap fitted in an open rectangular *** governing mathematical flow equations of the VOF model were solved using the ANSYS Fluent 14.0 software,reproducing the experimental conditions *** results show that the 3D CFD predictions using the VOF model closely fit the experimental data for glass bead particles.

关键词： Computational fluid dynamics (CFD) Sediment deposition Trap efficiency Invert trap Volume of fluid (VOF) model

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Mass-Casualty Distribution for Emergency Healthcare:A Simulation Analysis

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International Journal of Disaster Risk Science 2020年第3期11卷 364-377页

作者： mohsin Nasir Jat Raza Ali Rafique Edwards School of Business University of SaskatchewanSaskatoonSK S7N5A7Canada School of Management and Marketing Kean UniversityUnionNJ 07083USA

This study focuses on the casualty-load distribution problem that arises when a mass casualty incident(MCI)necessitates the engagement of multiple medical *** discrete event simulations,the study analyzed different MCI response regimes in Lahore,Pakistan,that vary in terms of the level of casualty-load distribution and the required coordination between the incident site and the responding *** terrorist attacks in this major metropolitan area were considered to set up experiments for comparing delays in treatment under the modeled *** analysis highlights that the number of casualties that are allowed to queue up at the nearest hospital before diverting the casualty traffic to an alternate hospital can be an important factor in reducing the overall treatment *** diverting the casualty traffic from the incident site to an alternate hospital can increase the travel time,while a delay in diversion can overload the nearest hospital,which can lead to overall longer waiting times in the *** casualty distribution mechanisms based only on the responding hospitals’available capacity and current load can perform inefficiently because they overlook the trade-off between the times casualties spend in traveling and in queues.

关键词： Casualty distribution Emergency response Mass casualty incidents Pakistan Urban terrorism

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Impact of dark current on pinned photo-diode capacitance of CMOS image sensor in low illumination regime

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Optoelectronics Letters 2024年第11期20卷 654-657页

作者： mohsin Suharwerdi Gausia Qazi Department of Electronics&Communication Engineering National Institute of TechnologySrinagar 190006India

Applications for quanta and space sensing both depend on efficient low-light *** precisely optimize and design image sensor pixels for these applications,it is crucial to analyze the mechanisms behind dark current generation,considering factors such as temperature,trap cross-section and trap *** thresholds for these generating effects are computed using optoelectrical technology computer aided design(TCAD)simulations,and the ensuing changes in pinned photo-diode(PPD)dynamic capacitance are *** generation models along with an interfacial trap model are used to compare PPD capacitance fluctuations during light and dark *** the use of this comparison study,current compact models of complementary metal oxide semiconductor(CMOS)image sensors can be modified to accurately capture the impacts of dark current in low-light *** model developed through this study demonstrates a deviation of only 6.85%from the behavior observed in physical *** results not only enhance our understanding of dark current generation mechanisms but also offer practical applications by improving the performance and accuracy of image sensors.

关键词： computer image capacitance

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