A comparison has been made of the air-kerma standards for medium-energy x-rays of the National Institute of Standards and Technology (NIST) and the Bureau International des Poids et Mesures (BIPM). The comparison involved a series of measurements at the BIPM and the NIST using the air-kerma standards and three NIST reference-class transfer ionization chamber standards. Reference beam qualities ...

UNLABELLED On the international level, International Organization for Standardization (ISO), European Committee for Standardization (CEN) and American Society of Heating, Refrigerating and Air Conditioning Engineers (ASHRAE) are writing and reviewing standards relating to the indoor environment on a regular basis. This presentation will focus on the development of standards for the indoor therm...

BACKGROUND This study examined potential associations between exposure to episodes of air pollution and alterations in semen quality. The air pollution, resulting from combustion of coal for industry and home heating in the Teplice district of the Czech Republic, was much higher during the winter than at other times of year with peaks exceeding US air quality standards. METHODS Young men from...

compost is a gradual process in nature by which organic materials are decomposed in the presence of air by microorganisms and fungi. the product is a valuable fertilizer that is used in different places even in home little gardens, so that it has signed as an unnoticed asset. with due attention to the importance of compost, its guidelines and standards should be evaluated. it is pointed and com...

this paper presents a model of a catchment area in northwest of iran. the researchers have studied ajichai basin which is located in the east part of orumiyeh lake, located at the longitude of 47 52’ e to 45 32’ e and the latitude of 37 26’ n to 38 30’ n. the researchers have chosen the data from tabriz upper air station which is the only one in the area. the research data are seven instability...

Recently, indoor air quality has attracted the attention of policymakers and researchers as a critical issue like that of external air pollution. Indoor air quality is more important as people spend time longer indoors than outdoors. Indoor environments are closed compared to external environments providing less opportunity for the pollutants to dilute. The emissions contain many substances tha...