the effect of the presence of perforations on he stresses of a plate is a problem which is of great interest in structural design and in the mathemattical theory of elasticity. among the many hole patterns that are likely to require consideration is the ring of equally spaced circular holes. the present worke investigates stress & strain analysis of a thin isotropic circular plate containing a ...

during 2010-2011 a faunistic survey was carried out for collection and identification of edaphic mesostigmatic mites (acari: mesostigmata) in jiroft and suburb. mites were extracted from soil samples by berlese funnel. the mites were cleared in nesbit fluid and were mounted in hoyer medium on microscopic slides. in this study 43 spices from 26 genera and 16 families were collected and identifie...

‏‎the community dynamics of aquatic coleoptera(insecta)in one of the spring-stream habitats of bammo national park in fars province called cheshmeh-ye-ghanbari is studied as a pilot project and model for acquaintance with and furthering the biodiversity studies on fauna of iran. sixteen species-populations out of nineteen of this community were already identified for their taxonomy and for thei...

this research was conducted in two protect and destroy region in the middle zagros, in illam province. in order to identification of ecological species group and evaluate density of regeneration, effect of many factors such as protection, vegetation, physiographic factors, physical and chemical properties of soil in study locations were studied. to achieve these purpose number of 54 plots using...

مراتع حدود نیمی از خشکی های جهان را در بر دارند و پوشش گیاهی آن در نتیجه تأثیر متقابل محیط و موجودات زنده به وجود آمده است و به عنوان یک اکوسیستم طبیعی مدیریت می شوند. علاوه بر مراتع، راه ها در عصر حاضر نیز از اجزا مهم و زیرساخت های اصلی زندگی نوین و توسعه کشورها به شمار می روند. جاده ها ساخته دست بشر هستند و جوامع گیاهی کنار جاده تحت تأثیر ساخت و ساز قرار دارند. پوشش "رودرال" به مجموعه ای از پ...

this research concentrates on the lithostratigraphy, biostratigraphy, microfacies and sedimentary environment of the asmari and gachsaran formations at southwest firuzabad. the thickness of the studied section in all 608.95 meters that 220.8 meters belong to the asmari formation and 387.95 meters belong to the gachsaran formation (champe and mol members). in the study area, the asmari formation...

based on the latest records of typhlops vermicularis merrem, 1820 from iran, this species is distributed in the northern and southern regions of the country. in this study, new records of typhlops vermicularis are presented and it is shown that distribution range of this species is extended towards the eastern and western iran, and according to the new distribution map, it can be assumed that t...

in this study, a simple, rapid and selective method was developed for the determination of dexamethasone. the proposed method is based on inhibitory effect of dexamethasone on the oxidation of orange-g by bromate in sulfuric acid media. the reaction was followed spectrophotometrically at 478.5 nm (?max). under optimum experimental conditions, (72.6 ?mol l-1 of orange-g, 0.76 mol l-1 of h2so4, 0...

چکیده مورچه‏ها با حمایت از شپشک‏ها در مقابل دشمنان طبیعی، می‏توانند برنامه‏های کنترل بیولوژیک آن‏ها را مختل ‏نمایند. طی سال‏های 1389 و 1390 با نمونه‏برداری از باغات مرکبات شهرستان‏های ساری و بهشهر، فون و فراوانی نسبی مورچه‏هایِ همراه با شپشک‏ها مورد مطالعه قرار گرفت. همچنین، تاثیر تراکم‏های مختلف کاست کارگر گونه‏ی santschi lasius turcicus بر میزان تغذیه و فراسنجه‏های واکنش تابعی حشرات ماده و لا...