Knitted Fabric Relaxation by Ultrasound and Its Characterization with Yarn-pullout Force

Jeddi, Ali A. A.,Mohammadi, V.,Rahimzadeh, H.,Honarvar, F. The Korean Fiber Society 2007 Fibers and polymers Vol.8 No.4

An investigation on the dimensional properties of plain knitted fabric produced from cotton yarn and subjected to different relaxation treatments is presented in this paper. The main aim of this research is to characterize the internal energy of fabric by using yarn-pullout test method in ultrasonic relaxation state and compare it with other common mechanical relaxation treatments. A comprehensive experimental analysis showed that, by using ultrasonic waves, the area geometry constant value $(k_s)$ achieved was higher than the conventional relaxation methods. Then, we introduced residual-energy forming and loss-energy uniforming. The former appeared due to fabric shrinkage and the later one appeared due to release of fabric loops from extra forces which imposed during knitting process. The results also indicated that ultrasonic waves energy causes more uniformity on loop and consequently, the fabric reaches to a less internal energy than washing treatment.

The Effects of Ischemic Postconditioning on Myocardial Function and Nitric Oxide Metabolites Following Ischemia-Reperfusion in Hyperthyroid Rats

Zaman, Jalal,Jeddi, Sajjad,Ghasemi, Asghar The Korean Society of Pharmacology 2014 The Korean Journal of Physiology & Pharmacology Vol.18 No.6

Ischemic postconditioning (IPost) could decrease ischemia-reperfusion (IR) injury. It has not yet reported whether IPost is useful when ischemic heart disease is accompanied with co-morbidities like hyperthyroidism. The aim of this study was to examine the effect of IPost on myocardial IR injury in hyperthyroid male rats. Hyperthyroidism was induced with administration of thyroxine in drinking water (12 mg/L) over a period of 21 days. After thoracotomy, the hearts of control and hyperthyroid rats were perfused in the Langendorff apparatus and subjected to 30 minutes global ischemia, followed by 120 minutes reperfusion; IPost, intermittent early reperfusion, was induced instantly following ischemia. In control rats, IPost significantly improved the left ventricular developed pressure (LVDP) and ${\pm}dp/dt$ during reperfusion (p<0.05); however it had no effect in hyperthyroid rats. In addition, hyperthyroidism significantly increased basal $NO_x$ (nitrate+nitrite) content in serum ($125.5{\pm}5.4{\mu}mol/L$ vs. $102.8{\pm}3.7{\mu}mol/L$; p<0.05) and heart ($34.9{\pm}4.1{\mu}mol/L$ vs. $19.9{\pm}1.94{\mu}mol/L$; p<0.05). In hyperthyroid groups, heart $NO_x$ concentration significantly increased after IR and IPost, whereas in the control groups, heart $NO_x$ were significantly higher after IR and lower after IPost (p<0.05). IPost reduced infarct size (p<0.05) only in control groups. In hyperthyroid group subjected to IPost, aminoguanidine, an inducible nitric oxide (NO) inhibitor, significantly reduced both the infarct size and heart $NO_x$ concentrations. In conclusion, unlike normal rats, IPost cycles following reperfusion does not provide cardioprotection against IR injury in hyperthyroid rats; an effect that may be due to NO overproduction because it is restored by iNOS inhibition.

The Effects of Ischemic Postconditioning on Myocardial Function and Nitric Oxide Metabolites Following Ischemia-Reperfusion in Hyperthyroid Rats

Jalal Zaman,Sajjad Jeddi,Asghar Ghasemi 대한생리학회-대한약리학회 2014 The Korean Journal of Physiology & Pharmacology Vol.18 No.6

Ischemic postconditioning (IPost) could decrease ischemia-reperfusion (IR) injury. It has not yet reported whether IPost is useful when ischemic heart disease is accompanied with co-morbidities like hyperthyroidism. The aim of this study was to examine the effect of IPost on myocardial IR injury in hyperthyroid male rats. Hyperthyroidism was induced with administration of thyroxine in drinking water (12 mg/L) over a period of 21 days. After thoracotomy, the hearts of control and hyperthyroid rats were perfused in the Langendorff apparatus and subjected to 30 minutes global ischemia, followed by 120 minutes reperfusion; IPost, intermittent early reperfusion, was induced instantly following ischemia. In control rats, IPost significantly improved the left ventricular developed pressure (LVDP) and ±dp/dt during reperfusion (p<0.05); however it had no effect in hyperthyroid rats. In addition, hyperthyroidism significantly increased basal NOx (nitrate+nitrite) content in serum (125.5±5.4 μmol/L vs. 102.8±3.7 μmol/L; p<0.05) and heart (34.9±4.1 μmol/L vs. 19.9±1.94 μmol/L; p<0.05). In hyper-thyroid groups, heart NOx concentration significantly increased after IR and IPost, whereas in the control groups, heart NOx were significantly higher after IR and lower after IPost (p<0.05). IPost reduced infarct size (p<0.05) only in control groups. In hyperthyroid group subjected to IPost, aminoguanidine, an inducible nitric oxide (NO) inhibitor, significantly reduced both the infarct size and heart NOx concentrations. In conclusion, unlike normal rats, IPost cycles following reperfusion does not provide cardioprotection against IR injury in hyperthyroid rats; an effect that may be due to NO overproduction because it is restored by iNOS inhibition.

How to Prevent Anastomotic Leak in Colorectal Surgery? A Systematic Review

Mohamed Ali Chaouch,Tarek Kellil,Camillia Jeddi,Ahmed Saidani,Faouzi Chebbi,Khadija Zouari 대한대장항문학회 2020 Annals of Coloproctolgy Vol.36 No.4

Anastomosis leakage (AL) after colorectal surgery is an embarrassing problem. It is associated with poor consequence. This review aims to summarize published evidence on prevention of AL after colorectal surgery and provide recommendations according to the Oxford Centre for Evidence-Based Medicine. We conducted bibliographic research on January 15, 2020, of PubMed, Cochrane Library, Embase, Scopus, and Google Scholar. We retained meta-analysis, reviews, and randomized clinical trials. We concluded that mechanical bowel preparation did not reduce AL. It seems that oral antibiotic or oral antibiotic with mechanical bowel preparation could reduce the risk of AL. The surgical approach did not affect the AL rate. The low ligation of the inferior mesenteric artery could reduce the AL rate. The mechanical anastomosis is superior to hand-sewn anastomosis only in case of right colectomies, with similar results in rectal surgery between the 2 anastomosis techniques. In the case of right colectomies, this anastomosis could be performed intracorporeally or extracorporeally with similar outcomes. The air leak test did not reduce AL. There is no interest of external drainage in colonic surgery but drains reduced the rate of AL and rate of reoperation after low anterior resection. The transanal tube reduced the rate of AL.

Resin Capacity of Technical Woven Fabrics: Pore Volume and Pore Shape Simulation

Hamid Reza Sharafat,Mehdi Kamali Dolatabadi,Ali. A. A. Jeddi 한국섬유공학회 2020 Fibers and polymers Vol.21 No.11

Nowadays, technical woven fabrics are broadly utilized as reinforcement of composites. Resin capacity of wovenfabric is one of the main challenges in laminate fabrication. Resin diffusion during fabrication of the composite is extremelydepended on fabric micro-morphology. The geometry of weave unit cell and its pore are fundamental factors in evaluatingresin capacity and resin diffusion within fabrics. The main attempt of this study was obtaining an approach to evaluate resincapacity of a woven fabric via simulating pore shape and pore volume. For this purpose, four basic unit cells for all kind ofweaves were simulated with the two shapes of tow cross-section: lens and racetrack. Afterwards, 3D shape and volume oftheir pores were simulated using this approach. The proposed approach is established on the base of initial data of fabric suchas tow setts, tow titers, planar density and thickness of a technical fabric. To assess the simulation, three types of wovenfabrics namely, plain, twill and satin were impregnated by epoxy resin using vacuum infusion process. The volume fractionsof the matrix and fibers of real composites were compared with simulated ones. It was demonstrated that the approach withracetrack assumption led to high degree of convergence with experimental results. The maximum relative error of pioneeredmethod to evaluate volume of the pore in this condition exceeded up to 1.43 %. Suitable correlation between volumefractions of the pore and void was observed in experimental data. It is experimentally demonstrated that the void volumefraction of composite will be increased with decrease of pore volume due to difficulty of wetting. In this paper, it is illustratedthat the resin capacity of a woven fabric is a function of vacuum level in vacuum infusion process. For instance, resincapacity of a certain plain fabric could be reduced up to 10 % under 60 kPa (0.6 bar) of vacuum in contrast with steady stateof fabric at room atmosphere.

Energy Harvesting by Cyclic Tensile Loading and Buckling via an Electrospun Polyblend Elastic Layer of PVDF/PU

Behrang Adeli,Ali Akbar Gharehaghaji,Ali Asghar Asgharian Jeddi 한국섬유공학회 2023 Fibers and polymers Vol.24 No.11

Energy harvesting through piezoelectric materials is considered an alternative to conventional power sources. Polyvinylidene fluoride (PVDF) is a piezoelectric material that has garnered significant attention from researchers. Blending PVDF with thermoplastic polyurethane can enhance its elastic properties. Numerous studies have successfully generated electric currents from piezoelectric materials by applying pressure and impact. This study, however, explores the generation of an electric current in piezoelectric materials by applying cyclic tensile loading. For this purpose, a tensile loading device was designed and built at the laboratory scale. Subsequently, a PVDF/PU polymer alloy layer (in a 25:75 ratio) was fabricated using the electrospinning method and installed in the loading device for testing. The results demonstrated that the electrical resistance decreased upon applying tension to the layer. Employing cyclic loading on the alloy layer resulted in an output voltage ranging between 3 and 9 mV, which confirmed the feasibility of energy harvesting from the polyblend layer. In a novel approach undertaken in this study, an electric current was generated by applying cyclic tensile loading, resulting in subsequent buckling. The potential energy harvesting mechanism from cyclic tensile loading and buckling is also elaborated upon. In addition, the study assessed and reported the effect of increasing the cyclic loading frequency on energy harvesting.