نتایج جستجو برای: green conditions
تعداد نتایج: 974998 فیلتر نتایج به سال:
In this paper, the meshless integral method based on the regularized boundary integral equation [1] has been extended to analyze the large deformation of elastoplastic materials. The updated Lagrangian governing integral equation is obtained from the weak form of elastoplasticity based on Green-Naghdi’s theory over a local sub-domain, and the moving least-squares approximation is used for meshl...
heterogeneous reagent systems have many advantages such as simple experimental procedures, mild reaction conditions and minimization of chemical wastes as compared to the liquid phase counterparts. al(hso4)3 as an heterogeneous, efficient, readily available, and cheap catalyst was synthesized and applied for the synthesis of 1,3-benzo[d]thiazole derivatives by condensation protocol of 2-aminoth...
During the "Green Sahara" period (11,000 to 5000 years before the present), the Sahara desert received high amounts of rainfall, supporting diverse vegetation, permanent lakes, and human populations. Our knowledge of rainfall rates and the spatiotemporal extent of wet conditions has suffered from a lack of continuous sedimentary records. We present a quantitative reconstruction of western Sahar...
Heterogeneous reagent systems have many advantages such as simple experimental procedures, mild reaction conditions and minimization of chemical wastes as compared to the liquid phase counterparts. Al(HSO4)3 as an heterogeneous, efficient, readily available, and cheap catalyst was synthesized and applied for the synthesis of 1,3-benzo[d]thiazole derivatives by con...
BACKGROUND Geriatric conditions may predict outcomes beyond age and standard risk factors. Our aim was to investigate a wide spectrum of geriatric conditions in survivors after an acute coronary syndrome. METHODS A total of 342 patients older than 65 years were included. At hospital discharge, 5 geriatric conditions were evaluated: frailty (Fried and Green scores), physical disability (Barthe...
جهت بهینه سازی شرایط تولید پروتئین هیدرولیز شده (شامل نسبت آنزیم به سوبسترا، دما و زمان) به منظور دستیابی به بالاترین خواص آنتی اکسیدانی، مینس تهیه شده از ضایعات میگوی ببری سبز (penaeus semisulcatus) پس از تعیین درصد پروتئین آن (13%، بر اساس وزن تر) با استفاده از دو پروتئاز تجاری آلکالاز و فلاورزایم بر اساس 18 تیمار تعیین شده با طرح آزمایشات سطح پاسخ برای هر آنزیم، هیدرولیز شده و با خشک کن انجم...
نفوذپذیری و رواناب بهعنوان مهمترین فرآیندها و پدیدههای فیزیکی در یک حوضهآبخیز میباشند که ارزیابی برخی از خصوصیات و پارامترهای آنها از اهمیت خاصی برخوردار است. با توجه به اینکه در حوضههایآبخیز تخمین تمامی پارامترهای موردنیاز جهت بررسی میزان نفوذپذیری و رواناب میسر نمیباشد لذا انتخاب مدلی که بتواند پیشبینی با دقت قابلقبولی را ارائه کند، امری ضروری بهنظر میرسد. تحقیق حاضر با هدف مقای...
[B(OH)3]0.78[B(OH)2(OSO3H)]0.22 or (BSA) was simply prepared by addition of chlorosulfonic acid to commercial boric acid at room temperature. This cheap and green solid acid was used as an efficient catalyst for synthesis of acylals from aldehydes under solvent-free conditions at room temperature.
Silica gel has been used for synthesis of biscoumarin derivatives starting from 4-hydroxycoumarin and aryl aldehydes. The reaction conditions are completely in agreement with green chemistry principles including sing water as media and a recyclable and safe catalyst. This method is also simple and inexpensive and leads to high yield of products in short reaction times.
A simple and mild method for tetrahydropyranylation of alcohols is reported at room temperature using a catalytic amount of 3-methylimidazolinium hydrogensulfate([Hmim]HSO4) as a green, efficient and reusable catalyst. Using solvent-free conditions, non-toxic and inexpensive materials, modest and clean work-up, short reaction times and high yields of the products are the advantages o...
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