Numerical Simulation of Dynamic Response of Water in Buried Pipeline under Explosion

Mohsen Parviz,Babak Aminnejad,Ali Reza Fiouz 대한토목학회 2017 KSCE JOURNAL OF CIVIL ENGINEERING Vol.21 No.7

Water pipelines are as a most important lifeline that may be subjected to explosion. In this paper, parametric studies were performed on some pipes buried in two soil types under blast loadings. The effects of different parameters, such as the physical properties of water, air, soil, pipe, and T.N.T were investigated. The Arbitrary Lagrangian-Eulerian (ALE) method was used in the LS-DYNA software. In general, the results revealed that a higher soil density causes a higher pressure on and stress transfer through a pipe. Explosion under a lower soil density causes less damage to a pipe and acts as a damper under the exploding waves. Based on the results, increased pressure and principal stress were resulted from the enhancements of the shear and bulk moduli and soil density, i.e., the former factors were very sensitive to the latter ones. The pressures of the substantial points of the pipes were obtained. The maximum explosion pressure and minimum pressure in the buried pipes occurred at the angles of nearly 0° to 45° and 45° to 90°, respectively.

Multi-objective optimization of friction stir welding using Taguchi design method, response surface model and particle swarm algorithm

Parviz Kahhal,Mohsen Ghasemi,Mohammad Kashfi,Ji Hoon Kim(김지훈) 한국자동차공학회 2021 한국자동차공학회 부문종합 학술대회 Vol.2021 No.6

Friction stir welding method was first developed in 1991 at the British Welding Institute as a solid state bonding method and used for welding aluminum alloys. This method has high energy efficiency and good compatibility with the environment. In general, the frictional stir welding process is suitable for metals that have a low melting point and their melting welding is not of good quality. In this research, multi-objective optimization of mechanical properties in friction welding of AH12 1050 aluminum alloy has been performed experimentally by using a combination of response surface methods and multi-objective particle swarm optimization. Taguchi method was also utilized to design the experimental program with two types of threaded cylindrical and simple tapered pins. Pin diameter, shoulder diameter, tool rotational speed, tool feed and tool deviation angle are selected as process variables, Specimen yield strength, impact toughness, failure strain, and hardness in heat affected zones (retreating and advancing sides) are considered as five objective functions. Finally, the results of optimization and a very good prediction accuracy indicate a very good agreement of the response surface model and experiments.

Effects of arginine and guanidinoacetic acid with or without phenylalanine on ascites susceptibility in cold-stressed broilers fed canola meal-based diet

Negin Delfani,Mohsen Daneshyar,Parviz Farhoomand,Younes Ali Alijoo,Sina Payvastegan,Gholamreza Najafi 한국축산학회 2023 한국축산학회지 Vol.65 No.1

In order to evaluate the effects of ARG sources (arginine [ARG] and Guanidinoacetic acid [GAA]) and phenylalanine (PHE) supplementation on performance, susceptibility to ascites, intestinal morphology, and nutrient digestibility in the cold-stressed broilers fed a canola meal (CM)-based diet, a 2×2 factorial experiment with four treatments was conducted. The dietary treatments included CM-based diet + 2.57 g/kg ARG, CM-based diet + 2.57 g/kg ARG + 1.5 g/kg PHE, CM-based diet + 1.8 g/kg GAA and CM-based diet + 1.8 g/kg GAA + 1.5 g/kg PHE. The corn-CM diet without supplementation was used as a negative control (NC) group in the fifth treatment that excluded the factorial arrangement. The results showed that adding ARG to diets without PHE supplement increased (p < 0.05) feed intake. Also, birds fed diets containing ARG had higher (p < 0.05) body weight gain (BWG) compared to those fed GAA added diets. Supplementation of PHE improved (p < 0.05) the FCR compared to groups fed diets without added PHE. Further, ARG addition increased (p < 0.05) plasma nitric oxide (NO) concentration, carcass, breast and leg yields, duodenal, jejunal, and ileal villus height (VH) to crypt depth (CD, and dry matter digestibility, while decreasing (p < 0.05) ascites mortality and right ventricle (RV) to total ventricle (TV) ratio compared to GAA added groups. Supplementation of PHE also declined susceptibility to ascites by reducing (p < 0.01) RV to TV ratio while increasing (p < 0.05) plasma NO level. The digestibility of ether extract also increased (p < 0.05) in broilers fed GAA supplemented diets versus those fed ARG added diets. The findings suggested that ARG may improve BWG and lower ascites incidence in broilers fed a diet based on CM under cold stress because of its antihypertensive effects. Moreover, the findings of this study demonstrated the importance of including PHE formulation in ARG-deficient diets to attenuate the adverse effects of cold stress on broilers. It was also concluded that GAA could be efficaciously used in cold-stressed broilers fed an ARG-deficient diet.

Evaluation of the Effect of (S)-3,4-Dicarboxyphenylglycine as a Metabotropic Glutamate Receptors Subtype 8 Agonist on Thermal Nociception Following Central Neuropathic Pain

Hosseini Marjan,Parviz Mohsen,Shabanzadeh Alireza P.,Zamani Elham 대한척추외과학회 2021 Asian Spine Journal Vol.15 No.2

Study Design: In this study, we decided to change the activity of periaqueductal gray (PAG)'s metabotropic glutamate receptors subtype 8 (mGluR8) by means of its specific agonist, (S)-3,4-dicarboxyphenylglycine (DCPG), and by knock downing it with mGluR8 siRNA. We then evaluated the changes in animal pain threshold levels in the face of painful thermal stimuli (thermal hyperalgesia).Purpose: Although several mechanisms have been examined for central neuropathic pain, researchers have so far failed to find the precise mechanism for the development and progression of this type of pain. Hyperalgesia is one of the most important complications of central neuropathic pain and there is not a consensus among researchers about the exact cause of this complication. In this study, we investigated the effect of activation of the PAG region mGluR8 on the threshold of pain response to thermal noxious stimulus in rats and measured mGluR8 expression.Overview of Literature: Spinal cord injury (SCI) produces an decrease in mGluR2/3 expression in the injured and vehicle-treated groups compared to normal levels, APDC and L-AP4 treated groups had higher expression levels of mGluR2/3. These findings suggesting that the level of mGluR expression after SCI may modulate nociceptive responses.Methods: Male Wistar rats were randomly assigned to five groups (n=10 per group). The clip compression injury model was used to induce chronic central neuropathic pain. Three weeks after SCI, DCPG, siRNA, or normal saline were administered to the intra-ventrolateral PAG region. Withdrawal threshold to the noxious thermal stimulus (e.g., heat hyperalgesia) was assessed through the tail-flick test. In order to assure involvement of this receptor, pain responses were compared with mice that received GRM8 siRNA.Results: We found that the mGluR8 agonist DCPG increased lead to an increased expression of mGluR8 in the PAG region. We also found that SCI can decrease the threshold of response to painful thermal stimuli; however, activation of mGluR8 with DCPG agonist did not significantly improve the tail-flick response.Conclusions: The results revealed that activation of mGluR8 in PAG is not capable of improving the thermal hyperalgesia threshold. Based on the decreased expression of mGluR8 after SCI induced by clip compression injury and its significant increase after treatment of siRNA against mGluR8, this method might still hold promise as an effective treatment of neuropathic pain. It can be concluded that increased expression of mGluR8 is due to the fact that DCPG prevents the death of neurons that express these receptors.

Hydraulic characteristics analysis of an anaerobic rotatory biological contactor (AnRBC) using tracer experiments and response surface methodology (RSM)

Yadollah Mansouri,Ali Akbar Zinatizadeh,Parviz Mohammadi,Mohsen Irandoust,Aazam Akhbari,Reza Davoodi 한국화학공학회 2012 Korean Journal of Chemical Engineering Vol.29 No.7

The hydraulic characteristic of an anaerobic rotating biological contactor (AnRBC) were studied by changing two important hydraulic factors effective in the treatment performance: the hydraulic retention time (τ) and rotational disk velocity (ω). The reactor hydraulic performance was analyzed by studying hydraulic residence time distributions (RTD) obtained from tracer (Rhodamine B) experiments. The experiments were conducted based on a central composite face-centered design (CCFD) and analyzed using response surface methodology (RSM). The region of exploration for the process was taken as the area enclosed by τ (60, 90 and 120 min) and ω (0.8 and 16 rpm) boundaries. Four dependent parameters, deviation from ideal retention time (Δτ), dead volume percentage and dispersion indexes (Morrill dispersion index (MDI) and dispersion number (d)), were computed as response. The maximum modeled Δτand dead volume percentage was 43.03 min and 37.51% at τ and ω 120 min and 0 rpm, respectively. While, the minimum predicted responses (2.57 min and 8.08%) were obtained at τ and ω 60min and 16 rpm, respectively. The interaction showed that disk rotational velocity and hydraulic retention time played an important role in MDI in the reactor. The AnRBC hydraulic regime was classified as moderate and high dispersion (d=0.09 to 0.253). As a result, in addition to the factors studied, the reactor geometry showed significant effect on the hydraulic regime.