نتایج جستجو برای: much higher sound velocities could be obtained for fiber composites compared with wood furthermore

تعداد نتایج: 14257306  

Journal: :journal of agricultural science and technology 2011
b. mohebby p. fallah-moghadam a. r. ghotbifar s. kazemi-najafi

the influence of maleic anhydride-polypropylene (mapp) (0, 2, 3 and 5%) as a compatibilizer on the wettability of polypropylene/wood flour/glass fiber hybrid composites was studied by using the contact angle determination technique. sample slats with a cross section of 10×70 mm were made by a twin screw extruder. specimens were conditioned at room temperature and the angles between the water dr...

An effort is made to gain insight on the effect of carbon nanotubes (CNTs) on the impact response of carbon fiber reinforced composites (CFRs) under low velocity impact. Certain amount of CNTs could lead improvements in mechanical properties of composites. In the present investigation, ABAQUS/Explicit finite element code (FEM) is employed to investigate various damages modes of nano composites ...

Journal: :جنگل و فرآورده های چوب 0
ابراهیم لشکربلوکی دانشجوی دکتری تخصصی، گروه علوم و صنایع چوب و کاغذ، دانشکدة منابع طبیعی دانشگاه تهران، کرج، ایران کامبیز پورطهماسی استاد، گروه علوم و صنایع چوب و کاغذ، دانشکدة منابع طبیعی دانشگاه تهران، کرج، ایران رضا اولادی استادیار، گروه علوم و صنایع چوب و کاغذ، دانشکدة منابع طبیعی دانشگاه تهران، کرج، ایران محسن کلاگری استادیار، مؤسسة تحقیقات جنگل ها و مراتع کشور، تهران، ایران

wood farming and especially poplar plantation is a key answer to the increasing demand of raw materials in wood and cellulosic industries. according to the diversity of wood applications, taking into account the wood quality and grading by wood farmers/buyers as well as its quantity can lead to an optimal management of production and consumption. in this regard, it is necessary to introduce and...

A. R. EL-Sissy M. S. El-wazery, O. F. El-Menshawy R. A. Elsad

This paper investigated the moisture absorption, mechanical behavior and the dielectric performance of hybrid and non-hybrid polymeric composites. Hand lay-up technique was used for processing carbon; glass reinforced polyester resin composites (non-hybrid) and carbon-glass/polyester hybrid composites with various fiber configurations. The maximum resistance of water absorption was obtained for...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه ارومیه - دانشکده ادبیات و علوم انسانی 1390

the present study was concerned with exploring the frequency and linguistic focus of corrective feedback types given by novice and experienced female teachers working with young learners and compared it with those of elementary classes for adults. moreover, it aimed at measuring learners’ acknowledgement of teachers’ corrective feedback in the form of uptake in relation to linguistic coverage o...

Journal: :iranian journal of chemistry and chemical engineering (ijcce) 2013
sima ranjbarian fathollah farhadi

experimental work was carried out to investigate the influence of impeller speed, granulation time, binder mass and their interactions on granule size distribution, mean size and binder content distribution in a conical high shear granulator. it was observed that the response of high shear granulation to changes in process parameters varies significantly from one operating condition to another....

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه شیراز - دانشکده ادبیات و علوم انسانی 1390

this study was carried out to investigate the effects of integrative vs. instrumental motivation, learning strategy use and gender on iranian efl learners. to this end, 120 efl learners both male and female majoring in english language and literature at shiraz university participated in the study. in order to conduct this study three instruments were used: oxford quick placement test, motivatio...

پایان نامه :0 1374

in fact, this study focused on the following questions: 1. is there any difference between the effect of functional/notional approach and the structural approaches to language teaching on the proficiency test of efl learners? 2. can a rather innovative language test referred to as "functional test" ge devised so so to measure the proficiency test of efl learners, and thus be as much reliable an...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه بیرجند - دانشکده کشاورزی 1390

abstract this study is carried out to determine the chemical composition in the three vegetative stages of the haloxylon sp., degradation parameters, with adding naoh and ca(oh2 ). for this purpose, in may and october and january 2010 enough some haloxylon sp. of the ammary area was prepared. crude protein and ash percentage are decrease, neutral detergent fiber percentage with pragress stage ...

Fiber-reinforced laminated composites are frequently preferred in many engineering projects. With the development in production technology, the using of the fiber reinforced laminated composites has been increasing in engineering applications. In the production stage of the fiber-reinforced laminated composites, porosities could be occurred due to production or technical errors. After a level o...

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