Convection heat transfer, entropy generation analysis and thermodynamic optimization of nanofluid flow in spiral coil tube

In this study, heat transfer, flow characteristics, and entropy generation of turbulent TiO2/water nanofluid flow in the spiral coil tube were analytically investigated considering the nanoparticle volume fraction, curvature ratio, flow rate and inlet temperature between 0.01–0.05 percent, 0.03–0.06, 1.3–3.3 l/min, and 15–27 °C, respectively. Results showed that the augmentation of the nanoparticle volume fraction increased the Nusselt number and friction factor up to 11.9% and 1.1%, respectively, while it reduced the entropy generation number up to 10.9%. Reducing the curvature ratio led to a maximum of 11.1% increase in the Nusselt number, while it resulted in a 5.6% increase in the entropy generation number. A decline in the inlet temperature from 21 °C to 15 °C proceeded a 28.4% and 7.1% increase in the heat transfer and pressure drop, respectively. The total entropy generation reduced with increasing nanoparticle volume fraction. For a low Reynolds number, a decrease in the curvature ratio led to a reduction in the total entropy generation, while reducing the curvature ratio was detrimental for a high Reynolds number. Analytical relations for optimum curvature ratio and optimum Reynolds number were derived. For the range of parameters studied in this paper, a range of optimum Reynolds number from 9000 to 12,000 was proposed.http://www.tandfonline.com/loi/uhte20hj2022Mechanical and Aeronautical Engineerin

Analyzing the behavior of the bullwhip effect considering different distribution systems

Recently, researchers have shown increased interest in quantifying the bullwhip effect, and several attempts have been made to alleviate this phenomenon within supply chain man- agement; however, absent from the current literature surrounding this topic is an in-depth analysis of the impact of different distribution systems, particularly cross-docking systems, upon the behavior of the bullwhip effect. This research aims to investigate the measure of the bullwhip effect in three different supply-chains; (I) with a central warehouse, (II) with a cross-docking system, and (III) without any distribution systems. These three different supply chains are subsequently analyzed to discover which supply chain helps reduce the bullwhip effect more. In doing so, the reasoning here is based on the premise that the demand process follows a mixed autoregressive-moving average model and all the stages employ the base stock policy for inventory replenishment, if necessary. In addition, the above mentioned supply chains are assumed to have two members in the retailer stage, with a different market share of the customer demand. It was found that factors such as lead time, market share of each retailer, autoregressive coefficient and moving average pa- rameter contribute to the selection of the most effective distribution system

Primary Hepatic Lymphoma Mimicking Cholangiocarcinoma

Primary hepatic lymphoma (PHL) presenting with obstructive jaundice is rare and can mimic a preoperative diagnosis of cholangiocarcinoma. We should consider PHL in patients with radiological hepatic disease with normal serum alpha-fetoprotein and carcinoembryonic antigen levels, and elevated lactate dehydrogenase. We present the case of a 67-year-old male with no significant medical history presented with abdominal pain, jaundice, fever, and abnormal liver function tests. Abdominal sonography and computed tomography scan suggested a diagnosis of obstructive jaundice and cholangitis due to cholangiocarcinoma (Klatskin tumor). A subsequent liver biopsy diagnosed PHL, and the patient was treated with combination chemotherapy, including rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP). PHL should be considered in patients presenting with biliary obstruction

Global Buckling Investigation in Welding of a Thin Wall Aluminum T Joint

In this paper global welding buckling distortion of a thin wall aluminum T joint is investigated. A thermo-elastoplastic model is employed to determine longitudinal residual stresses; analysis of thermal model and elastic-viscoplastic (Anand) model are decoupled. Molten puddle motion (speed of welding) is modeled by using birth and death element method and time dependent model. Three dimensional nonlinear-transient heat flow analysis has been used to obtain temperature distribution, and then by applying thermal results and using three dimensional Anand elastic-viscoplastic model, stress and deformation distributions are obtained. By applying residual stresses on a structural model and using eigenvalue methods, global buckling instability of the welded structure is determined

Prediction of Welding Buckling Distortion in a Thin Wall Aluminum T Joint

In this paper, local and global welding buckling distortion of a thin wall aluminum T joint is investigated. A thermo-elastic-viscoplastic model is employed to determine longitudinal residual stresses; analysis of thermal model and elastic-viscoplastic (Anand) model are uncoupled. Molten puddle motion (speed of welding) is modeled by using time dependent birth and death element method. Three dimensional nonlinear-transient heat flow analysis has been used to obtain the temperature distribution, and then by applying thermal results and using three dimensional Anand elastic-viscoplastic model, stress and deformation distributions are obtained during welding and after cooling. Local buckling is investigated by analyzing the history of stress and strain relations. Local buckling is assumed to occur at a point if a small change in the magnitude of stress causes large deformation during of the welding process. By applying residual stresses on a structural model and using eigenvalue methods, global buckling instability of the welded structure is determined

Investigation of Global Buckling Distortion in Welding of a Thin Wall Aluminum T Joint

In this paper global welding buckling distortion of a thin wall aluminum T joint is investigated. A thermo-elastoplastic model is employed to determine longitudinal residual stresses; analysis of thermal model and elastic-viscoplastic (Anand) model are decoupled. Molten puddle motion (speed of welding) is modeled by using birth and death element method and time dependent model. Three dimensional nonlinear-transient heat flow analysis has been used to obtain temperature distribution, and then by applying thermal results and using three dimensional Anand elastic-viscoplastic model, stress and deformation distributions are obtained. By applying residual stresses on a structural model and using eigenvalue methods, global buckling instability of the welded structure is determined. Some experiments are done for validating the numerical results

Development and evaluation of an injectable slow‐release progesterone formulation for estrus synchronization in ewes out of the breeding season

This study was aimed at developing a type of slow-release progesterone micro-particles useable in a single intramuscular injection for estrus synchronization in non-breeding season ewes. A total of 66 ewes were randomly assigned into four groups: CIDR (n = 16): exposed to intravaginal CIDR for 12 days, and three experimental groups, i.e., T100 (n = 16), T150 (n = 17) and T200 (n = 17), receiving a single intramuscular injection of 100, 150 and 200 mg slow-release progesterone, respectively. Blood sampling was performed on all ewes at five different times, and the ELISA method measured progesterone levels. No significant differences were observed in progesterone levels among the groups in each sampling time. More than 90% of ewes in the CIDR, T100 and T150 groups and all those in T200 showed estrus behaviour, and the rate was not significantly different between groups. The difference in the mean interval from progesterone treatment to estrus was also insignificant. The parturition rate declined by increasing the dose of injected progesterone; although it was similar in CIDR and T100 groups, it decreased significantly in T150 and T200. Since our injectable progesterone formulation was successful in the induction and synchronization of estrus in ewes out of the breeding season, it can be applied as an alternative to the conventional progesterone containing intravaginal devices