Sharif Digital Repository

Polylactic acid (PLA) scaffolds produced by the fused deposition modeling (FDM) method have biocompatibility, close Young's modulus to that of bone, and the ability to make complex shapes. However, PLA has some drawbacks like brittleness, inappropriate mechanical strength and hydrophobicity, and a low degradation rate. In this study, polyethylene glycol (PEG) (5 and 10 wt%) by solving method and titanium (Ti) particles (5 wt%) by two different methods were mixed with PLA to address the mentioned problems. Extruded filaments were investigated by X-ray diffraction (XRD), differential scanning calorimetry (DSC), and fourier transform infrared (FTIR). Surface morphology of the produced filaments... 

Flow through the pores of granular materials has many instances in practice. Therefore, it is interesting to realize how some parameters, such as the shape of the particles affect the passing flow. Following the recent mathematical theory proposed by the authors, this paper deals with the issue of how tortuosity and permeability are influenced by the particle shape. Comparison of the results with the experimental data reveals the competency of the theory in predicting the impact of particle geometry  

To mitigate environmental pollution and food contamination caused by inappropriate and excessive herbicide usage, most potent herbicides should be screened to control rice weeds. A research trial was executed for assessing the comparative efficacy of different herbicides to control rice field weeds and to evaluate the toxicity on rice under normal (distilled water) as well as different salinity levels (4 and 8 dS m-1). The study was designed to select the most potent herbicide and its appropriate dose for weed control of rice crop in coastal areas. Fourteen herbicidal treatments were included weed free crop, Pretilachlor (0.25, 0.50, 0.375 and 0.75 kg a.i. ha-1), Propanil + Thiobencarb (0.6... 

Contrast induced nephropathy (CIN) has been reported to be the third foremost cause of acute renal failure. Metabolomics is a robust technique that has been used to identify potential biomarkers for the prediction of renal damage. We aim to analyze the serum and urine metabolites changes, before and after using contrast for coronary angiography, to determine if metabolomics can predict early development of CIN. 66 patients undergoing elective coronary angiography were eligible for enrollment. Urine and serum samples were collected prior to administration of CM and 72 h post procedure and analyzed by nuclear magnetic resonance. The significant differential metabolites between patients who... 

Short term hydrothermal scheduling (STHTS) is a non-linear, multi-modal and very complex constrained optimization problem which has been solved using several conventional and modern metaheuristic optimization algorithms. A number of research articles have been published addressing STHTS using different techniques. This article presents a comprehensive review of research published for solving the STHTS problem in the last four decades. © 2013 IEEE  

Iron oxyhydroxide (α-FeOOH, Goethite) is one of the most thermodynamically stable iron oxides and a widespread soil mineral. In this study, a mixture of two phenolic extracts of rosemary and Echinacea was utilized as stabilizing and reducing agents for the synthesis of Goethite (FeOOH) nanoparticles without utilizing harmful toxic solvents. The resulting nanoparticles were characterized by X-ray powder diffraction (XRD), field emission scanning electron microscopy (FESEM)-energy dispersive spectroscopy (EDS), transmission electron microscopy (TEM), vibrating-sample magnetometer (VSM), thermogravimetry/differential thermal analysis (TG/DTA), and Brunauer–Emmett-Teller (BET). MTT assay was... 

The influence of manufacturing parameters such as compacting pressure, heat treatment and microstructure on the static and dynamic properties of Fe-1.75 Ni-1.5 Cu-0.5 Mo-0.6 C was investigated. Wear and fatigue tests were carried out on reciprocate wearing and tension compression mode, respectively. The results show that delamination wear mechanism of sintered steel is similar to that of conventional wrought or cast materials. But, in sintered material, open porosity acts as sites of generation and collection of wear debris or formation of subsurface cracks. Wear rate is decreased and fatigue strength is increased by heat treatment. © 2002 Elsevier Science Ltd. All rights reserved  

This paper proposes a new coil structure for inductive powering to wearable/implantable biomedical devices. This structure is virtually independent from the direction (and alignment) of the receiving coil relative to the transmitting coil. In addition to conducting experimental tests and characterizations, the proposed coil structure (energized by a transmitting coil) has been used to power up a real test system designed for wireless neural recording, operating at 1.2V and drawing 48 mW  

Efficient electron transport layers (ETLs) play a pivotal role in the performance of solar cells. In recent years, Indium sulfide (In2S3) has been studied as a promising ETL in CuInGaS(e)2, Cu2ZnSnS(e)4, and perovskite solar cells. Despite several studies on spray-deposited In2S3, there is no complete experimental investigation on In2S3 thin films. The effect of the molar ratio of S/In and the type of indium precursor on the structural, morphological, optical, and electrical properties of sprayed-In2S3 layers has been studied. Films were characterized using x-ray diffraction, scanning electron microscopy (SEM), optical transmission (UV-Vis), Mott-Schottky analysis, four-point probe, and... 

Purpose: Although it has been proposed that individuals with patellofemoral pain show less lower limb intersegmental coordination variability, the evidence to support this hypothesis is rare. The purpose of this study was, therefore, to evaluate whether individuals with patellofemoral pain exhibit less intersegmental coordination variability compared with healthy individuals during walking and running. Also, it was hypothesized that increasing task demand would exacerbate group differences regarding coordination variability measures. Methods: Three-dimensional kinematics were collected while 17 females with patellofemoral pain and 17 healthy females walked at preferred speed, and ran at... 

Purpose: There is a scarcity of studies evaluating the variability of couplings between proximal segments (trunk, pelvis, and thigh) in individuals with patellofemoral pain (PFP) while emerging evidence has suggested that aberrant motions of trunk and pelvis can have a contributory role in the etiology of PFP. The purpose of this study was, therefore, to evaluate the trunk, pelvis, and thigh intersegmental coordination variability in PFP compared with healthy individuals. Methods: Thirty-four participants (17 with PFP and 17 healthy controls) walked (at preferred speed) and ran (at preferred and fixed speed) on a treadmill each trial for 30 seconds. Three-dimensional kinematics were recorded... 

In the original publication, there were errors in some sentences, Figure legends, and Tables that are corrected as below:. © 2021, Taiwanese Society of Biomedical Engineering  

An economic-statistical design with multiple assignable causes following exponential distribution is presented in this paper for linear profiles. For this purpose, a tri-objective optimization model is proposed to minimize the cost with desired statistical performances. Average Run Length (ARL) as the primary statistical measure is employed for the appraisal of the designed linear profiles. The first objective to be minimized is a cost function that models the implementation cost in different states. The second objective is to maximize ARL or the in-control average run-length of the monitoring scheme. The third objective to be minimized is ARL 1 or the out-of-control average run-length of... 

Direct discharge of high-strength industrial effluent often upsets municipal wastewater treatment plant processes. This pilot study was undertaken to evaluate the performance of a UASB system in pre-treating effluent from a medium-size traditional slaughterhouse. Experiments were conducted in a continuous flow 500-1 pilot plant initially inoculated with 200 1 municipal anaerobic digested sludge. With an influent COD concentration of 3000-5000 mg/l, the system was started with a loading of 1.8 kg COD/m3.d (F/M of 0.24 kg COD/kg VSS.d) at 25°C. The granules formed after 4 months of operation were dark brownish with a diameter of 1-4 mm and a settling velocity of 20 m/hr. Once granules were... 

Gas pressure reduction stations are essential in energy distribution networks because even a minor failure of these systems causes disruptive consumer problems. This study aims to introduce and implement a new knowledge-based platform that uses the synthesized expert's opinions to improve gas pressure control facilities. Given the record of failure of gas transmission system components and the data's uncertain nature, a new fuzzy expert system is developed that takes advantage of the object-oriented programming paradigm to analyze failure modes and conditions. The artificial intelligent model is designed in C# programming language, and a user-friendly interface is developed for ease of... 

The Fontan surgery is performed on patients with a single ventricle heart defect to prevent the combination of highlyoxygenated and poorly-oxygenated blood. Blood flow in total cavopulmonary connection (TCPC) which culminates an ordinary Fontan operation is practically steady-state but this flow is not appropriate for respiratory systems. This article investigates an approach in Fontan surgery that has been recently proposed in order to make the pulmonary blood flow pulsating. Moreover, for investigating the compliance of vessels and its effects on blood flow in TCPC, we have used the FSI (Fluid Structure Interaction) method as well as rigid wall assumption for comparison purposes. Our TCPC... 

Electrospinning of composite polymer solutions provides fantastic potential to prepare novel nanofibers for use in a variety of applications. The addition of graphene (G) and graphene oxide (GO) nanosheets to bioactive polymers was found to enhance their conductivity and biocompatibility. Composite conductive nanofibers of polyaniline (PANI) and polyacrylonitrile (PAN) with G and GO nanosheets were prepared by an electrospinning process. The fabricated membranes were investigated by physical and chemical examinations including scanning electron microscopy (SEM), Raman spectroscopy, x-ray diffraction (XRD) and tensile assay. The muscle satellite cells enriched by a pre-plating technique were... 

A nonlinear integer programming model is developed in this article to solve redundancy allocation problems with multiple components having different failure rates in the series–parallel configuration using an active strategy. The main objective of this research is to select the number and the type of each component in subsystems so as the reliability of the system under certain constraints is maximized. To this aim, a weighted K-means clustering method is proposed, in which the analytical network process is employed to assign weights to the components of each cluster. As the proposed model belongs to the class of nondeterministic polynomial-time hardness problems, precise solution methods... 

A simple ultrasound-assisted dispersive micro-solid phase extraction method based on graphene-oxide (GO) nanosorbents (UAD-μ-SPE), followed by high performance liquid chromatography-ultraviolet detection (HPLC-UV) was developed for the simultaneous determination of theophylline, theobromine and caffeine in different infusion tea samples. GO was synthesized by Hummers method and characterized with field emission-scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), and Fourier transform infrared (FT-IR) spectroscopy. The GO sorbent was dispersed in the sample solution with the assistance of ultrasound to enhance adsorption and desorption performance and rates. The main parameters... 

A twodimensional model, based on conservation of mass, momentum and energy equations, is represented in this paper in which the coke combustion process, for iron ore sintering in a packed bed, is simulated numerically. The aforementioned packed bed consists of iron ore, coke, limestone and moisture. The main objective of iron ore sintering is producing resistant agglomerates which can be used in blast furnaces. For this purpose, the sinter mixture is partially melted in high temperature and finally molten is allowed to cool. The molten production and subsequently, the solidification process are totally dependent on composition and components of mixture. Changes in bed porosity, caused by...