نتایج جستجو برای: partial replacement of formaldehyde with furfural in the urea

تعداد نتایج: 25748884  

Journal: :جنگل و فرآورده های چوب 0
رباب غفاری کارشناس ارشد صنایع چوب و کاغذ، دانشکده منابع طبیعی، دانشگاه تهران،کرج، ایران کاظم دوست حسینی استاد گروه علوم و صنایع چوب و کاغذ، دانشکدة منابع طبیعی، دانشگاه تهران، کرج، ایران علی عبدالخانی استادیار گروه علوم و صنایع چوب و کاغذ، دانشکدة ‏منابع طبیعی، دانشگاه تهران، کرج، ایران سید احمد میرشکرایی استاد دانشکده علوم، دانشگاه پیام نور تهران، تهران، ایران محمد مهدی فائزی پور استاد گروه علوم و صنایع چوب و کاغذ، دانشکده منابع طبیعی، دانشگاه تهران، کرج، ایران

partial replacement of formaldehyde with furfural in the urea-formaldehyde resin on the formaldehydeemission, physical and mechanical properties of particleboard was investigated. the modulus ofrupture (mor), modulus of elasticity (moe), internal bond (ib), water absorption (wa), thicknessswelling (ts) and formaldehyde emission (fe) of poplar particleboards made with the modifiedresins were mea...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه رازی - دانشکده علوم 1388

abstract sensitive and precise voltammetric methods for the determination of trace amounts of furaldehydes, mainly as furfural (f) and 5-hydroxymethyl-2-furaldehyde (hmf), in waste waters and other matrices is described. determination of total furaldehyde at < ?g g-1 levels in alkaline buffered aqueous media was individually investigated. by the use of ordinary swv and adsorptive square wave ...

Journal: :جنگل و فرآورده های چوب 0
رباب غفاری کارشناس ارشد صنایع چوب و کاغذ، دانشکدة منابع طبیعی، دانشگاه تهران، کرج، ایران کاظم دوست حسینی استاد گروه علوم و صنایع چوب و کاغذ، دانشکدة‏ منابع طبیعی، دانشگاه تهران، کرج، ایران سید احمد میرشکرایی استاد دانشکدة علوم، دانشگاه پیام نور تهران، تهران، ایران علی عبدالخانی دانشیار گروه علوم و صنایع چوب و کاغذ، دانشکدة ‏منابع طبیعی، دانشگاه تهران، کرج، ایران

there are adequate sources for wood adhesives, but scarcity of oil resources can affect the cost and future availability of oil based resins. for avoiding of this process, seeking for feasibility of replacement of these oil feedstocks is necessary. in present work, thermal behavior of urea formaldehyde resin modified by furfural was investigated. the thermo-gravimetry was used for this purpose,...

پایان نامه :وزارت علوم، تحقیقات و فناوری - پژوهشکده علوم زمین سازمان زمین شناسی و اکتشافات مع 1390

the neogene intrusion masses in the noudeh-enghelab area located to the north of sabzevar ophiolite have cut the late cretaceous ophiolitic rocks, sedimentary- volcanic and eocene volcanic rocks and have been covered by pliocene and quaternary deposits. the margin is of lava with basalt, phyric andesite-basalt and andesite and the central parts (dome shaped) composed of phyric andesite-trachyan...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه خلیج فارس - دانشکده مهندسی 1393

in civil engineering concrete is a material combined of hydraulic cement, sand, gravel and water. gravel and sand compose 60 to 70 percent of concrete. these aggregates support compression force of concrete. cement paste acts as glue to stick grain together. in bushehr factories producing aggregates do not operate according to astm standards, so that fineness modulus (fm) of the produced sands ...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه تبریز - دانشکده ادبیات و زبانهای خارجی 1393

for several years, researchers in familiarity of efl teachers with post-method and its role in second and foreign language learners’ productions have pointed out that the opportunity to plan for a task generally develops language learners’ development (ellis, 2005). it is important to mention that the critical varies in language teaching was shown is the disappearances of the concept of method ...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه سیستان و بلوچستان 1390

a one dimensional dynamic model for a riser reactor in a fluidized bed catalytic cracking unit (fccu) for gasoil feed has been developed in two distinct conditions, one for industrial fccu and another for fccu using various frequencies of microwave energy spaced at the height of the riser reactor (fccu-mw). in addition, in order to increase the accuracy of component and bulk diffusion, instanta...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه سیستان و بلوچستان 1390

cement is an essential ingredient in the concrete buildings. for production of cement considerable amount of fossil fuel and electrical energy is consumed. on the other hand for generating one tone of portland cement, nearly one ton of carbon dioxide is released. it shows that 7 percent of the total released carbon dioxide in the world relates to the cement industry. considering ecological issu...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه صنعتی اصفهان - دانشکده ریاضی 1390

the main objective in sampling is to select a sample from a population in order to estimate some unknown population parameter, usually a total or a mean of some interesting variable. a simple way to take a sample of size n is to let all the possible samples have the same probability of being selected. this is called simple random sampling and then all units have the same probability of being ch...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه سیستان و بلوچستان - دانشکده مهندسی عمران 1392

abstract in aggregate, active forms of reactive silica with mineral names are sometimes associated with sand and gravel in concrete mixture. alkali hydroxides originated from alkalis in the cement or other resources form an alkaline silica gel with this reactive silica which becomes swallowed and expanded during time causing damage to concrete. there have been growing researches on alkaline r...

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