نتایج جستجو برای: ph

تعداد نتایج: 167675  

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه صنعت آب و برق (شهید عباسپور) - دانشکده عمران 1392

خاک های متورم شونده یک مشکل جهانی هستند بطوریکه خسارت های ناشی از وجود این خاک ها فقط در کشور آمریکا سالانه حدود 15 میلیارد دلار گزارش شده است (amer ali al-rawas et al) در نتیجه با توجه به مشکلات فراوان ناشی از وجود این نوع از خاک، توجه به حل این مشکلات نیز کاملاً جهانی شده است. دونالسن وجود این خاک ها را در سال 1970 در ایران نیز گزارش کرده است (فاخر،1372). بطور خلاصه می توان چنین عنوان نمود که ...

Journal: :physical chemistry research 0
massomeh ghorbanloo chemistry department, faculty of science, university of zanjan, zanjan, iran ali heydari department of chemistry, faculty of science, university of zanjan, 45371-38791 zanjan, ira

hydrogels, due to their unique potentials such as high-water content and hydrophilicity are interest for the controlled release of drug molecules. the present study aims to create a controlled-release system through the preparation and characterization of hydrogels based on ph-sensitive polymers such as poly (acrylic acid). poly (acrylic acid), p(aa), hydrogel has been synthesized by radical po...

Journal: :journal of dentistry, tehran university of medical sciences 0
mohammad hossein toodehzaeim associate professor, department of orthodontics, faculty of dentistry, shahid sadoughi university of medical sciences, yazd, iran elham khanpayeh assistant professor, department of orthodontics, faculty of dentistry, shahid sadoughi university of medical sciences, yazd, iran

o bjectives: the purpose of this study was to evaluate the effect of salivary ph on the shear bond strength (sbs) of orthodontic brackets to tooth surface. materials and methods: eighty intact premolars were randomly divided into four groups of 20.  after bonding a bracket on each tooth, the groups one to four were stored in artificial saliva at a ph of 3.8, 4.8, 5.8, and 6.8, respectively for ...

Journal: :iranian journal of basic medical sciences 0
elham khodaverdi department of pharmaceutics, school of pharmacy, mashhad university of medical sciences, mashhad, iran omid rajabi department of medicinal chemistry, school of pharmacy, mashhad university of medical sciences, mashhad, iran mohammad abdekhodai department of pharmaceutics, school of chemical engineering, sharif university, tehran, iran xiao yu wu department of pharmaceutics, school of pharmacy, university of toronto, toronto, canada

objective(s) in this study, a kind of ph sensitive composite membrane was prepared and drug permeation through it was investigated in terms of ph. rationale of this study originated from the fact that a ph change which may be a result of a disease state in the body can trigger drug release. materials and methods  here, a kind of ph sensitive composite membrane containing different nanoparticle ...

Journal: :international journal of environmental research 2010
m.s. vohra s.m. selimuzzaman m.s. al-suwaiyan

removal of thiosulfate (s2o32-, 200 mg/l) from simulated wastewater samples was investigated under varying co-pollutants and ph conditions employing the titanium dioxide (tio2) mediated photocatalysis. for thiosulfate only studies higher substrate removal was noted at lower ph with a specific trend of ph 4 > ph 7 > ph 10. furthermore, near complete thiosulfate removal was also achieved at ph 4....

Journal: :journal of agricultural science and technology 2016
s. versic l. kocsis b. pulko

the present study was carried out in order to test the effect of grapevine rootstocks root growth on biomass and leaf nutrition status in extreme soil conditions. own rooted cuttings of rootstocks fercal, teleki kober 5bb, georgikon 28 and four new rootstock hybrids from the breeding program of georgikon faculty, hungary (fb01, jb01, zamor 17 and szf10) were grown 3 months in pots. the 5 l pots...

Journal: :journal of plant physiology & breeding 2012
syavash hemmaty mohammad reza dilmaghani lotfali naseri

the main reasons for the fixation of some elements and consequently nutrient deficiencies, especially phosphorus, iron and zinc, are high levels of calcium (calcareous soils) and soil ph. two sulfur fertilizers (sulfur alone and sulfur + organic material + thiobacillus spp.) with two rates (2 and 4 kg sulfur/tree) were used to decrease soil ph and availability of p, fe and zn in apple trees dur...

Journal: :iranian journal of chemistry and chemical engineering (ijcce) 2005
hamid-reza kariminiaae hamedaani mohammad shahrokhi reza roostaazad

steady state and dynamic fermentations of baker's yeast in molasses based media were analyzed in a laboratory scale bioreactor. sugar and biomass balances together with the monod biokinetics were used to develop the process model. parameters of the model were obtained using collected experimental data. model predicted open loop responses to step changes in feed concentration as well as dilution...

ژورنال: :مجله دندانپزشکی جامعه اسلامی دندانپزشکان 0
دکتر مسعود فلاحی نژاد قاجاری masoud fallahinejad ghajari گروه آموزشی دندانپزشکی کودکان دانشکده دندانپزشکی دانشگاه علوم پزشکی شهید بهشتی. دکتر سپیده نبوی رضوی sepideh nabavi razavi

بررسی نقش ph نوشابه های ایرانی و خارجی بر میزان اروژن دندانها به روش آنالیز یون کلسیم دکتر مسعود فلاحی نژاد قاجاری* - دکتر سپیده نبوی رضوی** *- دانشیار گروه آموزشی دندانپزشکی کودکان دانشکده دندانپزشکی دانشگاه علوم پزشکی شهید بهشتی. **- متخصص دندانپزشکی کودکان. چکیده زمینه و هدف: هنوز مشخص نشده که توان اروزیو نوشابه ها صرفاً با افزایش مختصر ph و بدون افزودن کلسیم یا نمکهای فسفات افزایش می یابد یا...

ژورنال: :فصلنامه علمی - پژوهشی مهندسی منابع آب 2012
مسعود نوشادی ناصر طالب بیدختی احسان نجاتی

اگر چه کلرزنی آب، یک روش موفق و رایج در سراسر جهان بویژه در کشورهای در حال توسعه برای ضد عفونی آب است ولی کلرزنی می تواند باعث ایجاد مقادیر اندکی از تولیدات جانبی مثل تری هالومتان گردد. با توجه به اثرات سوء تری هالومتان ها, شناسایی و اندازه گیری این ترکیبات در آب از نقطه نظر مسایل بهداشتی و محیط زیست مهم می باشد. در این تحقیق نمونه های آب از 20 ایستگاه در نقاط مختلف شهر شیراز برداشت گردید که از...

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