نتایج جستجو برای: unsaturated polymer

تعداد نتایج: 109327  

ژورنال: علوم آب و خاک 2013
سید محمدعلی زمردیان, , پویان باقری , ,

Hydraulic conductivity is an important parameter in the design of geotechnical structures such as earth dam, floor construction, retaining walls and environmental structures. In unsaturated soils, hydraulic conductivity is a function of moisture content and soil water suction i.e. soil moisture characteristic curve. In this study, the values of unsaturated hydraulic conductivity in two soil typ...

Journal: :International Soil and Water Conservation Research 2022

Suction measurement has a vital role in unsaturated soil analysis. However, measuring suction remains challenging task due to number of issues such as the limited range measurement, cavitation, or long equilibrium time. It is even more when be carried on field. Hence, development new device which able measure high for duration without tedious maintenance and yet portable enough site required. I...

Journal: :journal of agricultural science and technology 2010
j. m. v. samani p. fathi

mathematical simulation of flow toward drains is an important and indispensable stage in drainage design and management. many related models have been developed, but most of them simulate the saturated flow toward drains without a due consideration of the unsaturated zone. in this study, the two dimensional differential equation governing saturated and unsaturated flow in porous media is numeri...

2015
Yaqi Wo Zi Li Elizabeth J. Brisbois Alessandro Colletta Jianfeng Wu Terry C. Major Chuanwu Xi Robert H. Bartlett Adam J. Matzger Mark E. Meyerhoff

The prolonged and localized delivery of nitric oxide (NO), a potent antithrombotic and antimicrobial agent, has many potential biomedical applications. In this work, the origin of the long-term storage stability and sustained NO release mechanism of S-nitroso-N-acetyl-D-penicillamine (SNAP)-doped CarboSil 20 80A polymer, a biomedical thermoplastic silicone-polycarbonate-urethane, is explored. L...

2010
Neslihan Alemdar A. Tuncer Erciyes Niyazi Bicak

Boric acid-pyridine mixture is presented as mild catalyst for polycondensation of semi-esters of ethylene glycol, in situ-generated by “cyclic anhydrideediol” reaction scheme from maleic, succinic and phthalic anhydrides. This catalyst system was demonstrated to give colorless polyesters in low molecular weights (Mn: 1650e1950 Da) within 4 h at 130 C 1H NMR spectra of the polyesters derived fro...

2017
Robin J. Hofmann Matea Vlatković Frank Wiesbrock

Hydrosilylation reactions, the (commonly) anti-Markovnikov additions of silanes to unsaturated bonds present in compounds such as alkenes and alkynes, offer numerous unique and advantageous properties for the preparation of polymeric materials, such as high yields and stereoselectivity. These reactions require to be catalyzed, for which platinum compounds were used in the initial stages. Celebr...

Journal: :Carbohydrate polymers 2014
J R Witono I W Noordergraaf H J Heeres L P B M Janssen

An important application of starch grafted with copolymers from unsaturated organic acids is the use as water absorbent. Although much research has been published in recent years, the kinetics of water absorption and the swelling behavior of starch based superabsorbents are relatively unexplored. Also, water retention under mechanical strain is usually not reported. Cassava starch was used sinc...

Journal: :Polymers & Polymer Composites 2022

The objective of the present study is to formulate added value polymer granite composite (PGC) based on (G) waste scraps as filler and unsaturated polyester (UP) obtained from chemically recycled post-consumed poly (ethyleneterephthalate) wastes (PET) a matrix be used in different candidate applications. Both were collected local dumping sites. Factors affecting properties acquired PGC products...

2017
George A. Kraus Peter Gottschalk

Trimethylsily1)oxy-substituted dienes react with 1 at low temperatures to afford annulated products. Disciplines Chemistry | Environmental Chemistry | Inorganic Chemistry | Organic Chemistry | Other Chemistry | Polymer Chemistry Comments Reprinted (adapted) with permission from The Journal of Organic Chemistry, 49(6); 1153-1154. Doi: 10.1021/jo00180a048. Copyright 1984 American Chemical Society...

Journal: :Dalton transactions 2009
Craig A Wheaton Paul G Hayes Benjamin J Ireland

Interest in the utility of polylactide as a commodity polymer has increased significantly in recent years due to numerous environmental advantages over conventional petrochemically derived plastics. As such, the development of novel catalyst systems for the ring opening polymerization of lactide has seen tremendous progress in the past decade. In particular, divalent metals (i.e. Mg, Ca and Zn)...

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