1、潍坊学院本科毕业论文 1 一、原文 building types and design A building is closely bound up with people， for it provides with the necessary space to work and live in . As classified by their use ,buildings are mainly of two types :industrial buildings and civil buildings .industrial buildings are used by various fac
2、tories or industrial production while civil buildings are those that are used by people for dwelling ,employment ,education and other social activities . Industrial buildings are factory buildings that are available for processing and manufacturing of various kinds ,in such fields as the mining indu
3、stry ,the metallurgical industry ,machine building ,the chemical industry and the textile industry . factory buildings can be classified into two types single-story ones and multi-story ones .the construction of industrial buildings is the same as that of civil buildings .however ,industrial and civ
4、il buildings differ in the materials used and in the way they are used . Civil buildings are divided into two broad categories: residential buildings and public buildings .residential buildings should suit family life .each flat should consist of at least three necessary rooms : a living room ,a kit
5、chen and a toilet .public buildings can be used in politics ,cultural activities ,administration work and other services ,such as schools, office buildings, parks ,hospitals ,shops ,stations ,theatres ,gymnasiums ,hotels ,exhibition halls ,bath pools ,and so on .all of them have different functions
6、,which in turn require different design types as well. Housing is the living quarters for human beings .the basic function of housing is to provide shelter from the elements ,but people today require much more that of their housing .a family moving into a new neighborhood will to know if the availab
7、le housing meets its standards of safety ,health ,and comfort .a family will also ask how near the housing is to grain shops ,food markets ,schools ,stores ,the library ,a movie theater ,and the community center . In the mid-1960s a most important value in housing was sufficient space both inside an
8、d out .a majority of families preferred single-family homes on about half an acre of land ,which would provide space for spare-time activities .in highly industrialized countries ,many families preferred to live as far out as possible from the center of a metropolitan area ,even if the wage earners
9、had to travel some distance to their work .quite a large number of families preferred country housing to suburban housing because their chief aim was to get far away from noise ,crowding ,and confusion .the accessibility of public transportation had ceased to be a decisive factor in housing because
10、most workers drove their cars to work .people were chiefly interested in the arrangement and size of rooms and the number of bedrooms . Before any of the building can begin ,plans have to be drawn to show what the building will be like ,the exact place in which it is to go and how everything is to b
11、e done. An important point in building design is the layout of rooms ,which should provide the greatest possible convenience in relation to the purposes for which they are intended .in a 潍坊学院本科毕业论文 2 dwelling house ,the layout may be considered under three categories : “day”, “night” ,and “services”
12、 .attention must be paid to the provision of easy communication between these areas .the “day “rooms generally include a dining-room ,sitting-room and kitchen ,but other rooms ,such as a study ,may be added ,and there may be a hall .the living-room ,which is generally the largest ,often serves as a
13、dining-room ,too ,or the kitchen may have a dining alcove .the “night “rooms consist of the bedrooms .the “services “comprise the kitchen ,bathrooms ,larder ,and water-closets .the kitchen and larder connect the services with the day rooms . It is also essential to consider the question of outlook f
14、rom the various rooms ,and those most in use should preferably face south as possible .it is ,however ,often very difficult to meet the optimum requirements ,both on account of the surroundings and the location of the roads .in resolving these complex problems ,it is also necessary to follow the loc
15、al town-planning regulations which are concerned with public amenities ,density of population ,height of buildings ,proportion of green space to dwellings ,building lines ,the general appearance of new properties in relation to the neighbourhood ,and so on . There is little standardization in indust
16、rial buildings although such buildings still need to comply with local town-planning regulations .the modern trend is towards light ,airy factory buildings .generally of reinforced concrete or metal construction ,a factory can be given a “shed ”type ridge roof ,incorporating windows facing north so
17、as to give evenly distributed natural lighting without sun-glare .Assessment of natural radioactivity levels and radiation hazards due to cement industry Abstract The cement industry is considered as one of the basic industries that plays an important role in the national economy of developing count
18、ries. Activity concentrations of 226Ra, 232Th and 40K in Assiut cement and other local cement types from different Egyptian factories has been measured by using -ray spectrometry. From the measured -ray spectra, specific activities were determined. The measured activity concentrations for these natu
19、ral radionuclides were compared with the reported data for other countries. The average values obtained for 226Ra, 232Th and 40K activity concentration in different types of cement are lower than the corresponding global values reported in UNSCEAR publications. The manufacturing operation reduces th
20、e radiation hazard parameters. Cement does not pose a significant radiological hazard when used for construction of buildings. 1. Introduction The need for cement is so great. That it considered a basic industry. Workers exposed to cement or its raw materials for a long time especially in mines and
21、at manufacturing sites as well as people, that spend about 80% of their time inside offices and homes (Mollah et al., 1986； Paredes et al., 1987) result in exposure to cement or its raw materials being necessary reality so we should know the radioactivity for cement and its raw material. There are m
22、any types of cements according to the chemical composition and hydraulic properties for each one. Portland cement is the most prevalent one. The contents of 226Ra, 232Th and 40K in raw and processed materials can vary considerably depending on their geological source and geochemical characteristics.
23、 Thus, the knowledge of radioactivity in these materials is important to estimate the radiological hazards on human health. The radiological impact from the natural radioactivity is due to radiation exposure of the 潍坊学院本科毕业论文 3 body by gamma-rays and irradiation of lung tissues from inhalation of ra
24、don and its progeny (Papastefanou et al., 1988). From the natural risk point of view, it is necessary to know the dose limits of public exposure and to measure the natural environmental radiation level provided by ground, air, water, foods, building interiors, etc., to estimate human exposure to nat
25、ural radiation sources (UNSCEAR, 1988). Low level gamma-ray spectrometry is suitable for both qualitative and quantitative determinations of gamma-ray-emitting nuclides in the environment (IAEA, 1989). The concentration of radio-elements in building materials and its components are important in asse
26、ssing population exposures, as most individuals spend 80% of their time indoors. The average indoor absorbed dose rate in air from terrestrial sources of radioactivity is estimated to be 70 nGy h?1. Indoors elevated external dose rates may arise from high activities of radionuclides in building mate
27、rials (Zikovsky and Kennedy, 1992). Great attention has been paid to determining radionuclide concentrations in building materials in many countries (Amrani and Tahtat, 2001； Rizzo et al., 2001； Kumar et al., 2003； Tzortzis et al., 2003). But information about the radioactivity of these materials in
28、 Egypt is limited. Knowledge of the occurrance and concentration of natural radioactivity in such important materials is essential for checking its quality in general and knowing its effect on the environment surrounding the cement producing factories in particular. Because of the global demand for
29、cement as a building material, the present study aims to: (1) Assess natural radioactivity (226Ra, 232Th and 40K) in raw and final products used in the Assiut cement factory and other local factories in Egypt. (2) Calculate the radiological parameters (radium equivalent activity Raeq, level index Ir
30、, external hazard index Hex and absorbed dose rate) which is related to the external -dose rate. The results of concentration levels and radiation equivalent activities are compared with similar studies carried out in other countries. 2. Experimental technique 2.1. Sampling and sample preparation Fi
31、fty seven samples of raw materials and final products used in the Assiut cement factories were collected for investigation. Twenty five samples of raw materials were taken from (Limestone, Clay, Slag, Iron oxide, gypsum) which are all the raw material used in cement industry, 20 samples of final pro
32、ducts were taken from Assiut cement (Portland, El-Mohands, White, and Sulphate resistant cement (S.R.C). For comparison with products from other factories, 8 samples were taken from the ordinary Portland cement from (Helwan, Qena, El-kawmya, Torra) and 4 samples were taken of white cement (Sinai and
33、 Helwan). Each sample, about 1-kg in weight was washed in distilled water and dried in an oven at about 110 C to ensure that moisture is completely removed, The samples were crushed, homogenized, and sieved through a 200 mesh, which is the optimum size to be enriched in heavy minerals. Weighted samp
34、les were placed in a polyethylene beaker, of 350-cm3 volume. The beakers were completely sealed for 4 weeks to reach secular equilibrium where the rate of decay of the radon daughters becomes equal to that of the parent. This step is necessary to ensure that radon gas is confined within the volume and the daughters will also remain in the sample. 2.2. Instrumentation and calibration
