Comparison of the Immediate Effects of Modified and Routine WarmUps on Knee Joint Function and Dynamic Balance in Athletes

Background: Warm-up before a sport activity is the most common preventive measure to reduce the incidences and severity of injuries during sport activities. This study investigated the effects of modified warm-up on balance and knee function as compared to those of routine warm-up in athletes. Methods: Twenty healthy athletes volunteered to participate in the study. At the beginning of the session, we evaluated the dynamic balance and the knee joint function variables by Star Excursion Balance Test (SEBT) and hop tests, and then the subjects did either modified or routine warm-up. Immediately after doing the warm-up, the dynamic balance and the knee joint function variables were assessed again. Each subject underwent both interventions in two sessions separated by at least 48 hours. Results: Statistically significant improvements were measured for modified warm-up compared to routine warm-up in eight directions of SEBT and four hop tests. (A: P=0.0001, AL: P=0.005, L: P=0.002, PL: P=0.005, P: P=0.005, PM: P=0.0001, M: P=0.001, AM: P=0.001) (One-leg hop test for distance: P=0.007, triple hop test for distance: P=0.003, triple crossover hop for distance: P=0.004, and 6 meter timed hop test: P=0.0001(. Conclusion: Modified warm-up showed greater impact on improving dynamic balance and some indicators of knee joint function in athletes, and it thereby provides more appropriate conditions for physical activity and reduces incidences of sport injuries

Design, synthesis, and characterization of thiol-decorated cross-linked graphene oxide framework for high-capacity Hg2+ ion adsorption

A 3D framework was effectively created by cross-linking graphene oxide nanosheets with 2,5-bis(((3-mercaptopropyl)dimethoxysilyl)oxy)terephthalohydrazide as a sulfur-containing linker, resulting in a successful synthesis of a novel chelating adsorbent. The resulting material showed remarkable efficiency in removing Hg2+ ions from polluted water, with a high adsorption capacity of 204.08 mg g−1 at pH 6 and 25 °C. The adsorption process followed a monolayer model described by the Langmuir isotherm, and the kinetics followed a pseudo-second-order model, indicating a chemical adsorption mechanism. The material demonstrated rapid adsorption and desorption, maintaining its performance even after multiple regeneration cycles. Overall, the synthesized 3D GOF stands out as an exceptional adsorbent due to its porous structure, efficient chelating functional groups, and robust efficacy in eliminating Hg2+ ions from contaminated water sources

Screening of inhibitors for remediation of asphaltene deposits: Experimental and modeling study

One of the most severe problems during production from heavy crude oil reservoirs is the formation of asphaltene precipitation and as a result deposition in the tubing, surface facilities and near wellbore region which causes oil production and permeability reduction in addition to rock wettability alteration in the reservoir. So one of the economical ways to prevent such incidents is using the chemicals which are called asphaltene inhibitor.In this study, the influence of three commercial inhibitors, namely; Cetyl Terimethyl Ammonium Bromide (CTAB), Sodium Dodecyl Sulfate (SDS), Triton X-100 and four non-commercial (Benzene, Benzoic Acid, Salicylic Acid, Naphthalene) inhibitors on two Iranian crude oils were investigated. This study extends previous works and contributes toward the better understanding of interactions between asphaltene and inhibitor. Effect of functional groups and structure of inhibitors on asphaltene precipitation were studied and it seems clear that the nature and polarity of asphaltene (structure and amount of impurities presented) has a significant impact on the selection of inhibitors. asphaltene dispersant tests and Core flood tests were designed for evaluation of inhibitors in static and dynamic conditions. The results revealed distinguished mechanisms for asphaltene solubilization/dispersion (such as hydrogen bonding, π–π interaction and acid-base interaction) and influence of additional side group (OH) on inhibition power of inhibitor.During the experiments, it was found that increasing inhibitor concentration may lead to the self-assembly of inhibitor and declining of asphaltene stabilization. So, finding optimum concentration of inhibitor with high efficiency and available at a reasonable price is very important. The results suggest that 600 ppm of CTAB and 300 ppm of SDS were approximately optimum concentrations for the studied crude oils. One of the most important findings that differ from previous studies is the revelation of the mechanism behind the SDS/asphaltene behavior in various concentrations of inhibitor. Effect of chosen inhibitors on asphaltene precipitation and consequently deposition in porous media was studied, and then experimental data were modeled for evaluation of permeability impairment mechanisms. Permeability revived after inhibitor squeezing and cake formation mechanism played an important role in permeability reduction before and after treatment in porous media. The findings can also be applied to prediction of future behavior of reservoirs in oil field scale and evaluation of formation damage in the different period of production if needed any treatment process. Keywords: Asphaltene, Precipitation, Deposition, Inhibitor, Permeability reductio

DME Synthesis over MSU-S Catalyst through Methanol Dehydration Reaction

MSU-S mesoporous catalyst with [SiO2]/[Al2O3] ratio of 55 was synthesized using tetrapropylammonium hydroxide (TPAOH) as a structure directing agent and hexadecyltrimethylammonium bromide (CTAB) as a surfactant. The catalytic activity of the calcined sample was evaluated for the dehydration of methanol to dimethyl ether (DME) in a vertical fixed bed microreactor at a weight hurly space velocity (WHSV) of 5 hr-1 .Temperature ranged from 230 °C to 380 °C and pressure was kept constant at 1 bar. The catalyst was characterized by XRD; consequently, the mesoporous structure of MSU-S catalyst was verified. The activity, selectivity, and stability of MSU-S catalyst were investigated in a vertical fixed bed reactor. An increase in methanol conversion was observed by increasing temperature. The equilibrium conversion of methanol was almost reached at 380 °C and selectivity decreased from 100% to 97% as temperature rose from 200 °C to 380 °C. The stability of MSU-S (Michigan State University) catalyst was investigated for 12 hr at 380 °C and a stable methanol conversion was observed during the mentioned time

Removal of Sulfur and Nitrogen Compounds from Diesel Fuel Using MSU-S

Abstract The performance of MSU-S and its forms modified with phosphotungstic acid (HPW) and nickel (Ni) for the desulfurization and denitrogenation of model diesel fuel were studied. According to the results of the characteristic tests (N 2 adsorption-desorption, XRD, SEM, and NH 3 -TPD), heteropoly acid incorporation causes higher acidity along with a negligible loss of structural aspects, while Ni impregnation leaves a drastic negative effect on mesoporous structure, crystalline phase, and particle shape along with a positive impact on surface acidity. With both modifications (HPW and Ni), the maximum increase of 33.18% and 6.88% was occurred for the adsorption loading of total sulfur and total nitrogen respectively. The adsorption loading and selectivity of all the adsorbents for total nitrogen were slightly more than those for total sulfur (the selective adsorption of nitrogen over sulfur). The pseudo-second order model can best fit the kinetics data and Freundlich model can best describe the equilibrium isotherm for all the species over Ni/HPW-MSU-S