نتایج جستجو برای: polymer urea

تعداد نتایج: 130317  

2008
Ardell D. Halvorson Stephen J. Del Grosso

We evaluated the eff ects of irrigated crop management practices on nitrous oxide (N2O) emissions from soil. Emissions were monitored from several irrigated cropping systems receiving N fertilizer rates ranging from 0 to 246 kg N ha−1 during the 2005 and 2006 growing seasons. Cropping systems included conventional-till (CT) continuous corn (Zea mays L.), no-till (NT) continuous corn, NT corn–dr...

2016
Saruchi B.S. Kaith Vaneet Kumar R. Jindal

A novel interpenetrating polymer network (IPN) has been synthesized through enzymatic initiation using lipase as initiator, glutaraldehyde as cross-linker, acrylic acid as primary monomer and acrylamide as secondary monomer. Biodegradability of synthesized interpenetrating polymer network was studied through soil burial and composting methods. Synthesized hydrogel was completely degraded within...

2001
James Runt David M. Weisberg Ruijian Xu James T. Garrett Evangelos Manias Alan Benesi Bernard Gordon Alan J. Snyder Gerson Rosenberg

Introduction Poly(urethane urea) multiblock copolymers [PUU] are used in variety of biomedical applications, including as blood-contacting components in ventricular assist systems. One of the drawbacks of these materials (particularly when used in completely implantable devices) is their relatively high permeability to air and moisture. Conventional biomedical PUU elastomers are generally compo...

Journal: :Analytical and bioanalytical chemistry 2013
Csaba Janáky Csaba Visy

In this topical review, progress achieved in amperometric sensing of different analytes over conducting polymer-based hybrid electrocatalysts is summarized. We report a variety of synthetic methods and the resulting hybrid assemblies, with the effectiveness of such strategies, for designing conjugated polymer-based hybrids as robust sensors for amperometric detection. Beyond incorporation of me...

2011
Shengsen Wang Ashok K. Alva Yuncong Li Min Zhang

Controlled release fertilizers (CRF) are produced with different rates and durations of nutrient release to cater to different crops with wide ranges of nutrient requirements. A rapid technique is needed to verify the label specifications of nutrient release rate and duration. Polymer-coated urea (PCU) (43% nitrogen [N]) and polymer-coated N, phosphorus (P), potassium (K) (PC_NPK; 14-14-14) fer...

Journal: :Journal of environmental quality 2008
Ardell D Halvorson Stephen J Del Grosso Curtis A Reule

We evaluated the effects of irrigated crop management practices on nitrous oxide (N(2)O) emissions from soil. Emissions were monitored from several irrigated cropping systems receiving N fertilizer rates ranging from 0 to 246 kg N ha(-1) during the 2005 and 2006 growing seasons. Cropping systems included conventional-till (CT) continuous corn (Zea mays L.), no-till (NT) continuous corn, NT corn...

2010
Chung-Yun Hse Mitsuo Higuchi

A powdery product was obtained by the reaction of methylolated melamine with alkyl resorcinols to form melamine-bridged alkyl resorcinols (MARs). The effects of the addition of this powder on the bonding strength and formaldehyde emission of urea–formaldehyde (UF) resins were investigated. Three types of UF resins with a formaldehyde/urea molar ratio of 1.3 synthesized by condensation at pH 1.0...

Journal: :Nutrient Cycling in Agroecosystems 2021

Abstract Optimizing nitrogen fertilizer management can reduce nitrous oxide (N 2 O) emissions. This study tested if split applying enhanced efficiency fertilizers (EEFs) resulted in lower N O emissions than equivalent rates of urea at planting. In semiarid southern Alberta, field trials were conducted during three years (planting to harvest) rainfed winter wheat crops. Annual ranged from 146 17...

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