Background and Objective: Quality control is one of the most important components in order to improve quality assurance in laboratories during analytical steps. For this purpose, coefficient of variation plays an important role. Due to the fast improvement in technology, application of inferential statistics for the comparisons of laboratory techniques, including instrument and chemicals and fa...

The Tera-eV Energy Superconducting Linear Accelerator (TESLA) is a 32 km long superconducting linear electron/positron collider of 500 GeV centre of mass energy (upgradeable to 800 GeV), presently in the planning phase at DESY [1,2]. About 21000 superconducting RF 9-cell cavities have to be cooled with superfluid helium at 2 K. The cavities are assembled in groups of 12 into about 16 m long cry...

It is shown that a microscopic system consisting of Brownian particles moving in a spatially asymmetric but periodic potential (ratchet) and contacting with the alternating hot and cold reservoirs along space coordinate and an external force applying on the particles may work as a refrigerator. In order to clarify the underlying physical pictures of the system, the heat flows via both the poten...

This paper investigates the effects of nonazeotropic refrigerant mixtures (NARMs) as replacement of CFCs. The thermodynamic propert1es of NARM R22/R142b which is harmless to ozone layer are analyzed. The tests about water-to-water heat pump and dual-evaporator refrigerator-freezer using R22/R142b as alternative to R12 are introduced. The test results show R22/Rl42b is of energy conserving effec...

7. The research and development department of an appliance company suspects the energy consumption required of their 18 cubic foot refrigerator can be reduced by a slight modification to the current motor. Sixty 18 cubic foot refrigerators were randomly selected from the company’s warehouse. The first 30 had their motors modified while the last 30 were left intact. The energy consumption (kilow...

BACKGROUND High consumption of nonalcoholic beverages is one of the causes of dental erosion. Annual consumption of beverages in Iran is 48 LPCY (Lit per capita per year) that is equal to 144 bottles per capita in year and is relatively a high rate. Taking this into consideration, the present study was planned to determine the pH and fluoride content of beverages consumed in Kerman, south east ...