Silver recovery from radiographic film processing effluents by hydrogen peroxide: Modeling and optimization using response surface methodology

Mohammadreza Eskandarian,Mohammadreza Eskandarian,Javad Zabarjadi,Ali Ehsani,Amirhossein Afshar 한국화학공학회 2014 Korean Journal of Chemical Engineering Vol.31 No.1

The recovery of silver from X-ray film processing effluents by precipitation using hydrogen peroxide as the precipitating agent was studied. Response surface methodology (RSM) and central composite design (CCD) were applied to achieve optimum conditions. Linear, square and interactions effects between parameters to study of a second order polynomial equation were obtained. Optimum condition included the volume of H2O2 0.8 ml/min, pH=5.5, ethylene glycol 9 ml in the experimental condition. In these conditions silver recovery percentage was predicted as 92.8%. The experiment was conducted in triplicate under optimized conditions. Silver recovery percentage and average of precipitate were obtained as 91.5% and 423.19mg, respectively, which were close to the predicted amount achieved by the model.

Preventive Effect of Tamsulosin on Postoperative Urinary Retention

Mohammadreza Mohammadi-Fallah,Sepehr Hamedanchi,Ali Tayyebi-Azar 대한비뇨의학회 2012 Investigative and Clinical Urology Vol.53 No.6

Purpose: To investigate the prophylactic effect of Tamsulosin, a super-selective alpha-1a adrenergic blocking agent, on the development of urinary retention in men undergoing elective inguinal herniorrhaphy. Materials and Methods: From May 2010 through November 2011, a total of 80 males who underwent elective inguinal herniorrhaphy in a university hospital were included in this study. Patients were randomly assigned to one of two groups. In group one (control), the patients were given two doses of placebo orally, 6 hours before surgery and 6 to 12 hours after surgery. Patients in group two were given 0.4 mg of Tamsulosin orally in the same manner as the placebo. All patients were closely followed for 24 hours post-operatively, and any voiding difficulties or urinary retention was recorded. Results: There were 40 patients in group one (control group) and 40 patients in group two (Tamsulosin group). The patients’ mean age was 64 years. In group one, 6 patients and in group two, 1 patient required catheterization. Thus, 15% of patients in group I and 2.5% of patients in group II had urinary retention. The difference in the requirement for catheterization was statistically significant (p=0.04). The technique of herniorrhaphy, the side of the body in which the hernia was located, the type of anesthesia, the duration of the surgery, and the severity of pre-operative urinary symptoms had no significant effect on the incidence of urinary retention. Conclusions: The use of perioperative Tamsulosin represents an effective strategy to reduce the risk of post-operative urinary retention following inguinal herniorrhaphy. Purpose: To investigate the prophylactic effect of Tamsulosin, a super-selective alpha-1a adrenergic blocking agent, on the development of urinary retention in men undergoing elective inguinal herniorrhaphy. Materials and Methods: From May 2010 through November 2011, a total of 80 males who underwent elective inguinal herniorrhaphy in a university hospital were included in this study. Patients were randomly assigned to one of two groups. In group one (control), the patients were given two doses of placebo orally, 6 hours before surgery and 6 to 12 hours after surgery. Patients in group two were given 0.4 mg of Tamsulosin orally in the same manner as the placebo. All patients were closely followed for 24 hours post-operatively, and any voiding difficulties or urinary retention was recorded. Results: There were 40 patients in group one (control group) and 40 patients in group two (Tamsulosin group). The patients’ mean age was 64 years. In group one, 6 patients and in group two, 1 patient required catheterization. Thus, 15% of patients in group I and 2.5% of patients in group II had urinary retention. The difference in the requirement for catheterization was statistically significant (p=0.04). The technique of herniorrhaphy, the side of the body in which the hernia was located, the type of anesthesia, the duration of the surgery, and the severity of pre-operative urinary symptoms had no significant effect on the incidence of urinary retention. Conclusions: The use of perioperative Tamsulosin represents an effective strategy to reduce the risk of post-operative urinary retention following inguinal herniorrhaphy.

HOTAIR Long Non-coding RNA: Characterizing the Locus Features by the In Silico Approaches

Mohammadreza Hajjari,Saghar Rahnama 한국유전체학회 2017 Genomics & informatics Vol.15 No.4

HOTAIR is an lncRNA that has been known to have an oncogenic role in different cancers. There is limited knowledge of genetic and epigenetic elements and their interactions for the gene encoding HOTAIR. Therefore, understanding the molecular mechanism and its regulation remains to be challenging. We used different in silico analyses to find genetic and epigenetic elements of HOTAIR gene to gain insight into its regulation. We reported different regulatory elements including canonical promoters, transcription start sites, CpGIs as well as epigenetic marks that are potentially involved in the regulation of HOTAIR gene expression. We identified repeat sequences and single nucleotide polymorphisms that are located within or next to the CpGIs of HOTAIR. Our analyses may help to find potential interactions between genetic and epigenetic elements of HOTAIR gene in the human tissues and show opportunities and limitations for researches on HOTAIR gene in future studies.

Slide Session : OS-GAS-08 ; Gastroenterology : Correlation of Noninvasive Serum Fibrosis Markers with Stage of Fibrosis in Chronic Hepatitis

( Mohammadreza Abdollahi ),( Aliasghar Pouri ),( Mohammadhossein Somi ) 대한내과학회 2014 대한내과학회 추계학술대회 Vol.2014 No.1

Background: Chronic hepatitis is defined as a necroinflammatory disease of the liver continuing for at least six months. The aim of this study was to evaluate the role of noninvasive fibrosis markers by assessing the association among histological staging and these diagnostic parameters in patients with chronic hepatitis. Methods: We studied 221 patients with chronic hepatitis between 2011 and 2013. Routine biochemical indices and serum fibrosis indexes such as aspartate aminotransferase (AST)/alanine aminotransferase (ALT) ratio (AAR), AST to platelet ratio index (APRI) and Fibrosis 4 score (FIB-4) were determined, and the histological grade and stage of the liver biopsy specimens were scored according to the Ishak scoring system. Receiver operating characteristic curve (ROC) analysis was conducted to compare diagnostic accuracies of these markers for prediction of significant fibrosis. Results: We identified 221 liver biopsies from chronic hepatitis patients with contemporaneous laboratory values for imputing AAR, APRI and FIB-4. From all, 135 males (61.1%) and 86 females (38.9%), with the mean age of 39.6±14.4 were studied. FIB- 4, APRI and AAR were correlated significantly with the stage of fibrosis, with a higher correlation coefficient than other markers in the patients with Hepatitis B (r= 0.46), C (r= 0.58) and autoimmune hepatitis (r=0.28). FIB-4 (AUROC=0.84) and APRI (AUROC= 0.78) was superior to AAR at distinguishing severe fibrosis from mild-to-moderate fibrosis, especially in patients with hepatitis B and C. Conclusions: Application of these markers was good at distinguishing significant . - brosis and decreased the need for staging liver biopsy specimens among patients with chronic hepatitis.

Melt-spun Liquid Core Fibers: A CFD Analysis on Biphasic Flow in Coaxial Spinneret Die

Mohammadreza Naeimirad,Ali Zadhoush 한국섬유공학회 2018 Fibers and polymers Vol.19 No.4

Simulation of co-flowing behavior in a coaxial geometry (based on the designed spin pack) has been performed using properties of two immiscible liquids to represent flowing regime while passing through the spinneret for production of liquid core fiber (LCF) by one single step high-speed melt-spinning process. Computational Fluid Dynamics (CFD) simulations confirmed the continuous liquid core channel, obtained in bicomponent melt-spinning of LCF. Also different interface morphologies could be observed: from jetting to dripping and transition core-annular regime, based on the simulation parameters, affecting the driving forces. Results showed different co-flow regimes by systematic variation in nondimensional parameters (flow rate ratio, viscosity ratio, Reynolds number, Weber number and Capillary number), individually. Also diameter of the core liquid is reduced in a logarithmic mode by increasing the outer liquid’s flow rate. Flowing morphologies at different conditions were plotted in 2D state diagrams, illustrating transition from dripping to jetting regime by changing two different parameters. This CFD analysis bears potential for simple ways of controlled jet breakup in microfluidic devices, which currently primarily rely on Rayleigh-Taylor breakup. Notably this work highlights the melt-flow regime in the spinneret to realize developed fiber core structures at different conditions during bicomponent melt-spinning. Using various materials with different properties in liquid core fiber production promises many applications for this new generation fiber in very near future.

EEDARS: An Energy-Efficient Dual-Sink Algorithm with Role Switching Mechanism for Event-Driven Wireless Sensor Networks

( Mohammadreza Eslaminejad ),( Shukor Abd Razak ),( Abdul Samad Haji Ismail ) 한국인터넷정보학회 2012 KSII Transactions on Internet and Information Syst Vol.6 No.10

Energy conservation is a vital issue in wireless sensor networks. Recently, employing mobile sinks for data gathering become a pervasive trend to deal with this problem. The sink can follow stochastic or pre-defined paths; however the controlled mobility pattern nowadays is taken more into consideration. In this method, the sink moves across the network autonomously and changes its position based on the energy factors. Although the sink mobility would reduce nodes` energy consumption and enhance the network lifetime, the overhead caused by topological changes could waste unnecessary power through the sensor field. In this paper, we proposed EEDARS, an energy-efficient dual-sink algorithm with role switching mechanism which utilizes both static and mobile sinks. The static sink is engaged to avoid any periodic flooding for sink localization, while the mobile sink adaptively moves towards the event region for data collection. Furthermore, a role switching mechanism is applied to the protocol in order to send the nearest sink to the recent event area, hence shorten the path. This algorithm could be employed in event-driven and multi-hop scenarios. Analytical model and extensive simulation results for EEDARS demonstrate a significant improvement on the network metrics especially the lifetime, the load and the end-to-end delay.

Saturated hydraulic conductivity variation in a small garden under drip irrigation

Mohammadreza Khaledian,Mahmoud Shabanpour,Hajar Alinia 한국자원공학회 2016 Geosystem engineering Vol.19 No.6

The objective of this study was to identify the effects of the tillage on some soil properties, and the spatial and temporal variability of some soil properties. The research was conducted in a small kiwi fruit garden under drip irrigation with high frequency. The garden is located at the University of Guilan in Rasht in the North of Iran. This study was based on the use of the Beerkan infiltration method to provide soil hydraulic properties using a single ring infiltration test. After that, Ks was calculated with the BEST algorithm. The spatial structure of Ks was identified by the semivariogram using the GS + software. After identifying spatial variation, seven sets of infiltration measurements were taken for temporal variations assessment in three selected points in the garden. The results demonstrated that hydraulic properties changed over time. This change was related to the effects of wetting and drying cycles, soil biological activity and the effects of the root system. Changes in wetting dimensions due to tillage and temporal variations of Ks were studied with Schwartzman and Zur equation. It can be recommended that in order to mitigate agro-environmental risk, the application of fertilizers should be done after the restructuration of tilled soil.

Integrated nozzle - flapper valve with piezoelectric actuator and isothermal chamber: a feedback linearization multi control device

Mohammadreza Kamali,Seyed Ali Jazayeri,Farid Najafi,Kenji Kawashima,Toshiharu Kagawa 대한기계학회 2016 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.30 No.5

This paper introduces a new nozzle-flapper valve with isothermal chamber using piezoelectric actuator. It controls the pressure and flow rate simply, effectively and separately. The proposed valve uses isothermal chamber presenting practical isothermal condition due to its large heat transfer interfaces filled by metal wool. The valve uses stacked type piezoelectric actuator with unique advantages. By using this valve, a simple method has been fulfilled to control flow rate or pressure of ideal gases in a pneumatic actuators. Experimental results demonstrated applications of the proposed valve to control either pressure or flow rate in pneumatic circuits. This valve can be also used in the pilot stage valve to actuate the main stage of a much bigger pneumatic valve. Designated structure contains only one pressure sensor installed on the isothermal control chamber, capable of controlling both pressure and flow rate. The desired output mass flow rate of the valve is controlled by the pressure changes during positioning of piezoelectric actuator at proper position. The proposed valve can control steady and unsteady oscillatory flow rate and pressure effectively, using nonlinear control method such as feedback linearization approach. Its effectiveness is demonstrated and validated through simulation and experiments.

Wire electrical discharge machining of ASP30 tool steel

Mohammadreza Shabgard,Ahad Gholipoor,Mohammad Hatami 대한기계학회 2016 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.30 No.8

Wire electrical discharge machining is a non-traditional cutting process for machining of hard and high strength materials. This study analyzed the effects of the main input parameters of wire electrical discharge machining of ASP30 steel (high alloyed Powder metallurgical [PM] high speed steel) as the workpiece on the material removal rate and surface roughness. The input parameters included spraying pressure and electric conductivity coefficient of the dielectric fluid, linear velocity of the wire and wire tension. The machined surface quality was evaluated using SEM pictures. Results indicated that increasing the spraying pressure of dielectric fluid leads to a higher material removal rate and surface roughness and that increasing the wire tension, linear velocity of wire, and electric conductivity of the dielectric fluid decreases the material removal rate and surface roughness.

Performance evaluation of a twin-shaft gas turbine engine in mechanical drive service

Mohammadreza Tahan,Masdi Muhammad,Z. A. Abdul Karim 대한기계학회 2017 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.31 No.2

This study aimed at quantifying the effect of mechanical load on the performance of an 18.7 MW offshore gas turbine engine. The targeted engine is of two-shaft free power turbine configuration that operates as a mechanical driver for a process compressor in the gas compression service. The study is a part of a comprehensive performance health monitoring program to address the diagnostic and prognostic requirements in oil and gas offshore platforms and is motivated by the need to provide in-depth knowledge of the gas turbine engine performance. In this work, only the context of some design point key performance parameters and a limited set of collected operational data from the gas turbine in the real plant are available. Therefore, three major tasks, namely design point calculation, characteristic map tuning and off-design performance adaption, were needed to be performed. In order to check the validity of the proposed model, the obtained simulation results were compared with the operational data. The results indicate the maximum inaccuracy of the proposed model is 3.04 %. Finally, by employing the developed model, the engine capability for power generation when exposed to various load speeds is investigated. The obtained result demonstrates at the maximum gas generator speed, every 3 % decrease in mechanical speed leads to 1 % decline in the gas turbine power output. Moreover, when the gas turbine operates under design power load and mechanical speed is lower than 80 % of design speed, every 1 % decrease in load speed results in 0.2 % loss in thermal efficiency. The established relationship will assist proper assessment of mechanical drive gas turbines for performance health monitoring.