Review Article
Naeim Banisaeid; Nematollah Jafarzadeh Haghighi Fard
Abstract
Background and Objective: Freshwater salinization in the world occurs during man-made urban and industrial activities. These activities range from groundwater abstraction for drinking water in coastal areas to the level at which seawater overflows with fresh water to de-hardening processes in industrial ...
Read More
Background and Objective: Freshwater salinization in the world occurs during man-made urban and industrial activities. These activities range from groundwater abstraction for drinking water in coastal areas to the level at which seawater overflows with fresh water to de-hardening processes in industrial use to prevent damage to facilities. Materials and Methods: In this research, using the study of reference books as well as internet search, with google search engine, in databases of springer, science direct, online library wiley, iwap online, etc., articles related to biological treatment of saline wastewater, checked. Results: The results show that the performance of bacterial metabolism, among other factors, depends on the ambient osmotic pressure, which is closely related to the concentration of salt in the mineral liquid. High salt concentration has direct and indirect effects on bacterial activity and this will have a significant impact on the capacity to use biological processes in saline wastewater put. Conclusion: The best way to treat this type of wastewater is to use halophilic bacteria that are less sensitive to salt additions. Phosphorus removal and nitrogen oxidation are more sensitive to the removal of organic matter in these wastewaters. In general, according to studies, the use of combined anaerobic-aerobic process can create a higher efficiency in the treatment of such wastewater, provided that if the amount of salt is added to more than 12% of halophilic bacteria is added to the system.
Research Article
Rahman Sharifi; Hamed Ali
Abstract
There are many different methods to modify the mechanical properties of saturated clayey soils. It may be chosen depending of location and function of the structure. among those methods, preloading in presence of vertical drains and installation of stone columns are similar together and it is the cause ...
Read More
There are many different methods to modify the mechanical properties of saturated clayey soils. It may be chosen depending of location and function of the structure. among those methods, preloading in presence of vertical drains and installation of stone columns are similar together and it is the cause of comparison. In this thesis, each mechanism of modification of soil was studied lonely and then the results of every method were compared with all together. Subsequently the mentioned approaches were graded technicaly. For this reason, a two dimentional finite element software was used to make the models. It should be necessary to forcast the results of choosing one approach, because there is no proper procedure available for engineers to choose one of these method as the first index, and also the long time that must be spent for in situ consolidation.the results show that the finite element program has the ability of simulating the consolidation phenomena in saturated clayey soils and declare that installation of stone columns is better than preloading by installation of vertical drains. Of course, there are many parameters influences the selection of superiority.
Research Article
مدیریت ساخت و مدیریت پروژه
Solmaz Abdi; Abbas Tajaddini; Zahra Sabzi
Abstract
There are serious concerns about the environmental risks of industrial states activities affecting the life quality of occupants living in the neighbor cities and areas. This research aims at managing and reducing the environmental effects of pollutants, induced by the activities of industrial states ...
Read More
There are serious concerns about the environmental risks of industrial states activities affecting the life quality of occupants living in the neighbor cities and areas. This research aims at managing and reducing the environmental effects of pollutants, induced by the activities of industrial states (e.g. Kowsar state), on the life quality of neighbor cities occupants (here: Karaj city). There are currently 59 active industrial units in Kowsar state, that are producing commercial products in various sectors such as: chemical, food, metallic, mineral, cellulosic, and electrical industries. To determine the pollution pattern and influence ranking of its environmental pollutants, the current condition of the state and city were studied. Then, the impacts of its environmental pollutants were examined. To collect the required research data, two questionnaires were designed. The first questionnaire was filled out by experts adopted from construction and environmental engineering sectors, and then analyzed using the Delphi method. This resulted in eliminating the unimportant factors from the questionnaire. Accordingly, the second (refined) questionnaire was created, and again completed by research experts. The new data were analyzed using the WASPAS method. The results showed that the highest impact of the industrial state is on the ‘life quality of its own personnel’. This item was followed by items of ‘life disruption of neighbor occupants’, ‘permeation of malodorous aroma in the area’, ‘spread of noise pollution’, and, ‘release of toxic gases’ respectively. Some recommendations for better managing the problem are presented here.
Research Article
Kian Asghari; Saeed Mehrabi; Shahriar Tavousi Tafreshi
Abstract
Nowadays, concrete has received special attention due to reasons such as the ease of preparation of constituent components, low costs compared to other materials, favorable engineering properties, extraordinary durability, formability, and most importantly, positive interaction with the environment. ...
Read More
Nowadays, concrete has received special attention due to reasons such as the ease of preparation of constituent components, low costs compared to other materials, favorable engineering properties, extraordinary durability, formability, and most importantly, positive interaction with the environment. Although the construction of concrete with the main components of cement, aggregate and water is very simple and conventional, but the addition of new materials such as fibers causes the fragility of concrete to be significantly reduced and it shows ductile behavior under different loads. Fibrous concrete is actually a type of composite that, with the use of reinforcing fibers in the concrete mixture, does not easily fall apart under the impact of impact loads, and its tensile strength increases above normal.Concrete gains very little strength at very low temperatures, so when the degree of saturation of the concrete is not sufficiently reduced by the dewatering action, it is necessary to protect the concrete against damage caused by freezing. The use of polyolefin fibers and the effect of appropriate granulation in the concrete mixing plan is one of the effective factors in reducing the effect of freezing. In this article, the reason for the use of polyolefin fibers, the manufacturing method, mechanical properties, fiber concrete applications, and the effect of mixing design granulation on the compressive strength and abrasion percentage of fiber concrete samples in the normal environment and freezing, according to the results of applications and researches has been discussed.
