introduction earth has ever been exposed to environmental hazards. the hazards are continually occurring in the world in the recent years. among them, atmospheric elements have created many human and financial losses in different regions. one of the hazards is dust events and in its severe case is dust storm. it happens more frequently in arid and semiarid regions in deserts and their surroundi...

* Reprint requests t o Dr . M. Z. A . Badr. 0340-5087/79/0800-1128/$ 01.00/0 p h e n e t h y l r a d i c a l s g i v e s e t h y l b e n z e n e w h i l e t h e i r d i m e r i s a t i o n g i v e s r ise t o 2 , 3 d i p h e n y l b u t a n e w h i c h m a y b e d e h y d r o g e n a t e d u n d e r t h e i n f l u e n c e o f t h e f r e e r a d i c a l s p r e s e n t i n t h e r e a c t i o ...

introduction climate change happens due to abnormal changes of climate within the earth’s atmosphere and their consequences. one of the most significant effects of climate change is the irreversible damage to some floral species and forest ecosystems. tree species reflect the impact of climate changes on their ring width. generally, tree rings vary in size each year depending upon the environme...

A t heo rem p r o v i n g sys tem has been programmed f o r a u t o m a t i n g m i l d l y complex p r o o f s b y s t r u c t u r ­ a l i n d u c t i o n . One pu rpose was t o p r o v e p r o p e r ­ t i e s o f s i m p l e f u n c t i o n a l p rograms w i t h o u t l o o p s o r a s s i g n m e n t s . One can see t h e f o r m a l sys tem as a g e n e r a l i z a t i o n o f number t h e ...

t h e m s e l v e s i n t h e p e r s p e c t i v e o f r e s e a r c h o n t h e o r i g i n s o f s p e e c h , a n d d o n o t a s k t h e q u e s t i o n w h e r e t h e s o u n d s y s t e m t h e y a s s u m e c o m e s f r o m . T o i l l u s t r a t e t h i s p r o c e s s , I w i l l r e d o s o m e s i m u l a t i o n s s i m i l a r t o t h o s e p r e s e n t e d e a r l i e r , b u...

a n d c o m b i n e t h e a d v a n t a g e s o f s t r u c t u r e d d e v e l o p m e n t w i t h t h e a d v a n t a g e s o f o b j e c t o r i e n t a t i o n . A s d a t a a b s t r a c t i o n s b e c o m e m o r e c o m p l e x , t h e b o x s t r u c t u r e u s a g e h i e r a r c h y a l l o w s s t e p w i s e r e f i n e m e n t o f t h e s y s t e m d e s i g n w i t h r e f e r e...

the aim of this study was to investigate the effect of adding different levels of zinc sulfate in semen extender on bovine sperm quality during cryopreservation. semen was collected from 4 holstein bull twice a week and the proper samples were pooled. semen were allocated to four extender treatments consisted of 0, 50, 100, 150 µm of zinc sulfate in 5 replicates and then, were frozen. post-thaw...

application of various composts has been intensified in agriculture, due to manifestation of negative effects of chemical fertilizers on environment and soil fertility. however, their usage should be accompanied by environmental and nutritional studies. to study the effects of sulfur granular compost on yield and yield components of two wheat cultivars, a pot experiment was conducted in a compl...

D i a l o g u e s y s t e m s s h o u l d p r o v i d e a c o o p e r a t i v e i n f o r m a t i o n a l d i a l o g u e a i m e d a t k n o w l e d g e s h a r i n g . In t h e p a p e r s p e e c h a c t s o f a s s e r t i o n (SAA) a r e a s s u m e d t o be t h e m e a n s o f a c h i e v i n g t h i s g o a l . A t y p o l o g y o f SAAs i s p r o p o s e d w h i c h r e f l e c t s c e ...

This paper describes damping capac i t y and mechanical p roper t ies o f Zn-8-20%A1 and Zn-8-20%Al-0.02-0.04XMg a l l o y cast ings. Zn-8-20%A1 a l l o y casti ngs show h igh damping when quenched from 573K. Small amount o f Mg a d d i t i o n t o these a l l o y cast ings lowers damping capaci ty considerably b u t e f f e c t i v e t o reduce decomposition through aging a t 423K f o r 48hrs ...