2760 research outputs found
Sort by
Fast identification method of total normal surface absorptances using inverse techniques
No full text
Seismic risk and damage prediction : case of the buildings in constantine city (Algeria)
No full text
Effect of cold and scarification on seeds germination of pistacia atlantica L. for rapid multiplication
No full textThis study was carried out to determine the effects of mechanical scarification and cold treatment of seeds at + 4°C before sowing seed of Pistacia atlantica. In these cases, the durations at cold temperature, which have been taken into account, are successively 60, 50, 40, and 30 days. After these periods, the rate of germination and the speed of germination are calculated every 4 days. The rates of germinations concerning the not scarified seeds having undergone a cold treatment lasting 50 days are the most important that is a value of 39% from the 09-05-2010 until the 29-05-2010. The speed germination is maximum that is 89 germinated seeds /4 days. In addition this same rate reaches a maximum of 70%. Concerning the pistachio tree seeds of the atlas treated mechanically with duration of cold treatment at + 4°C during 30 days. For the same category of seed the speed of germination is maximum that is 214 seeds/4 days. Thus the scarification and the 30 days stay are the fastest means which allow to obtain the seedlings of pistachio tree in a rather short tim
Effet des granulats sulfurés sur les résistances mécanique et la durabilité des BHPF avec ajouts de laitier = Effect of sulfur aggregates on mechanical resistance and durability for SFRHPC with the addition of slag
No full textThe transformation of sulfides present in the aggregate to sulfates causes internal sulfate attack (ISA) by formation of secondary ettringite in the hardened concrete. This pathological ettringite crystallizes, the generated pressure is greater than the tensile strength of the concrete. It generates internal swelling and causes disorders that can severely damage the structures. Favors to their structural and economic performance, high performance concrete steel fiber (SFRHPC) are increasingly used in construction. Increase productivity and reduce construction time on site. They provide substantial weight savings, therefore it is possible to build with less formwork, less concrete to set up and fewer reinforcement than ordinary concrete. The purpose of this study is to determine the effect of sulfur present in the hornfels crushed aggregates, on the mechanical strength, durability, and the microstructure of SFRHPC with the addition of blast furnace slag. In ordinary concrete, the pyrite aggregates cause cracking by expansion when they are in wet land. In high performance concretes this phenomenon is greatly reduced or absent. This is the result of a very low porosity, reduced flow of moisture that cannot propagate to aggregate. And sulfide is stable and cannot be transformed into aggressive sulfat
Estabishment of a methodology for eco-innovation based on inventive principle
No full textToday, in the context of product innovation, the environmental dimension takes a new dimension and can not
be separated from other product requirements which make it competitive. Tools are available but unfortunately
proficiency levels required for their use are at the expert’s level. In the present work we have adopted an approach using a
qualitative evaluation matrix including parameters related to the ease of use of the product related to the organizational
preparation for the appropriation of an eco-design approach, in addition to the standard factors of eco-efficiency. In order
to help the designer to make a decision, an adapted TRIZ method is proposed (Téoria Rechénia Izobrétatelskikh Zadatch
or theory of inventive problem solving). The applicability of this method is justified by the many contradictions in the
choices in a study of the life cycle and can help designers and companies to choose an approach to attain a satisfying level
of eco-design for the resources invested in it. An application, based on inventive principles, will be adapted and
completed.This matrix can help the designer to reduce the scope of his creative investigations. The results of our
methodological approach have been tested on cases of creative projects and a certain number of recently patented
project
Biogas production from waste activated sludge using cattle dung inoculums : effect of total solid contents and kinetics study
No full textThermophilic anaerobic digestion of waste activated sludge (WAS) was experimentally studied in this research. WAS using cattle dung inoculums with total solids (TS) concentrations of 12.02, 17.58, 23.28, 26.75, and 35.2 g L-1 were digested anaerobically in a batch digester at thermophilic temperatures (55 C°) for a retention period of 15days. Effect of TS concentration on the quality and quantity of the produced gas, pH variation, and the kinetics of biogas production were investigated. The results showed that biogas production potential and biogas production rate increased with an increasing TS concentration. The maximum biogas yields from TS concentration 12.02, 17.58, 23.28, 26.75, and 35.2 g L-1 were 0.186, 0.189, 0.93, 0.213, and 0.231 L/(g VS)-1, respectively. Modified Gompertz equation was employed to model the biogas production at different substrate concentrations. The equation gave a good approximation of the maximum biogas production (Rm) and the biogas yield potential (P) with correlation coefficient (R2) over 0.996. The digestion at TS concentration 35, 8 g L-1 gave the best results. The maximum biogas production reaches 0.856 L day-1, and the biogas yield was 6.650 L at the end of the 13th day of the experiment. This amount of biogas with composition 72.59% of CH4, and 23.6% of CO2 is equivalent to 190 KWh of electricity. These results show that WAS mixed with cow dung is an effective feedstock for biogas production, giving a high cumulative biogas yiel
محاولة بناء خلية لليقظة الإستيراتيجية بالمؤسسات الصغيرة والمتوسطة كأداة لتنمية الصادرات خارج المحروقات : دراسة عينة من المؤسسات الصغيرة والمتوسطة
No full textص. 188-224تعد المؤسسات الصغيرة والمتوسطة حجز الزاوية في بناء قاعدة اقتصادية متينة كونها تنجح دائما في الإستمرار والنمو، بفضل قدرتها على التكيف والتوصل الى طرائق مبتكرة في الإنتاج والتسويق،إلا أن عولمة الإقتصاد أصبحت تطرح إشكالية تتعلق بضمان نمو المؤسسات الصغيرة والمتوسطة التي تريد الولوج للأسواق الدولي
Vegetable oils extraction of polycyclic aromatic hydrocarbons from an Algerian quagmire
Get PDFPolycyclic aromatic hydrocarbons (PAHs) are carcinogenic substances which are resistant to environmental degradation due to their high hydrophobic nature. Soil contaminated with PAHs pose potential risks to human and ecological health, therefore concern over their adverse effects have resulted in extensive studies on their removal from contaminated soils. The main propose of this work was to extract this pollutants from two real quagmire samples from the region of Hassi Messaoud (Algeria), using three kinds of vegetable oils (Peanut oil, rapeseed oil, and coconut oil) which are naturals, cost effectives, and biodegradables extractors at two different temperatures (30 and 70 °C). Three PAHs that are representing of their present in contaminated quagmire were characterized using IR-FTIR and HPL