.hot metal gas forming of tubes can be used in various industries such as automotive and aerospace industries. in this process tube is formed at elevated temperatures, by using gas instead of fluid pressure. lower required pressure and low power are its advantages in comparison to hydroforming process. in this paper, a hot metal gas bulging process of an aluminum alloy tube has been investigate...

in this investigation, hydroxyapatite (hap) nanostructure with uniform morphologies, controllable size, nano-dispersion and narrow-size distribution in diameter has been synthesized successfully by low-temperature hydrothermal process, and the as-synthesized powders were characterized by energy-dispersive x-ray spectroscopy, scanning electron microscopy, high-resolution transmission electron mi...

The output power of a photovoltaic (PV) system depends on the external solar irradiation and its own temperature. In order to obtain more power from the PV system, the maximum power point tracking (MPPT) is necessary. However, when the PV is partially shaded, there will be multiple peaks in the power-current (P-I) curve. The conventional MPPT methods may be invalid due to falling into the local...

Polymerase chain reaction (PCR) is widely used in biochemical analysis to amplify DNA and RNA in vitro. The PCR process is highly temperature sensitive, and thermal management has an important role in PCR operation in reaching the required temperature set points at each step of the process. The goal of this research is to achieve a thermal technique to rapidly increase the heating/cooling therm...

In this study, a periodic zigzag channel with rectangular cross-section has been used in order to obtain a high-efficiency system for cooling a polymer electrolyte fuel cell. An appropriate function of fuel cells and enhancement of their lifetime require uniform temperature conditions of around 80°C. On the other hand, due to volume and weight constraints, a low-density compact heat exchanger i...

In this study, Aluminium2024- Graphite composites containing 5, 10, 15 and 20 weight percent of graphite were produced by solid assisted melt disintegration (SAMD) technique which resulted in production of Al/Gr powder mixtures which subsequently consolidated and sintered for preparation of Al/Gr composites. In this technique, powder mixture was prepared by addition of flake graphite (mean diam...

Background: It has been hypothesized that COVID-19 is less prevalent in regions with warm climates. Contradictory results led us to investigate the correlation between temperature and the cumulative COVID-19 incidence rate. Method: We obtained COVID data from CRONALAB, COVID-DASHBOARD, and MCMC databases of Fars province, linked data, and finalized daily COVID-19 cases. Daily data on the temp...

Ziegler-Natta (ZN) based co-polymerization processes for the production of linear low-density polyethylene (LLDPE) generally give rise to a non-uniform incorporation distribution comonomer. It has been shown that lowering titanation temperature during catalyst synthesis can increase evenness this distribution. However, polymerization process parameters also affect resulting To investigate these...

Considering importance of stress concentration around holes and notches of arbitrary shape in a given elastic medium for modern engineering, a two dimensional model for a thermoelastic problem in an hexagon region with an elliptic hole is established. The expressions for the temperature distribution and thermal stresses which have their importance in nuclear engineering are obtained for the mod...