Estimating the Impact of Water Pricing on Water Use Efficiency in Semi-arid Cropping System: An Application of Probabilistically Constrained Nonparametric Efficiency Analysis

By introducing proper pricing instruments, farm level water can be used more efficient. But it demands a proper estimation strategy to analyse the efficiency and the input use behavior of farms under the new pricing system. As most production relationships are stochastic in nature, excluding random errors and noise from model specifications often leads to criticism. By using a probabilistically constrained programming formulation, an empirical estimation of stochastic data envelopment analysis (DEA) is done to analyze the efficiency of irrigation water use in the agricultural production system in the Krishna river basin, India. The results illustrate that water demand is higher for farms at, or close to the frontier and lower for those with low efficiency levels. In a second step, a simulation model is developed by using the frontier and economic efficiency derived from stochastic DEA to analyse the impact of water pricing on water use efficiency and water use behaviour. It is shown that an increase in the water price would not cause sizeable profit loss, if the pricing system is administered on a volumetric basis, but water demand would decrease substantially.     

Micro/nanocellular polyprolene/trans-1,4-polyisomprene (PP/TPI) blend foams by using supercritical nitrogen as blowing agent

Toughed polypropylene (PP) foams, with the combination of blending with trans-1,4-polyisoprene (TPI) and micro/nanocellular structure in the matrix, were prepared using a batch foaming process and N₂ as the blowing agent. The incorporation of TPI in the PP matrix induces the enhanced formability and the slightly improved ductility and toughness compared to the neat PP. The simultaneous existence of the TPI phase and micro/nanocellular structure makes the fracture behavior follow the shear yielding of a bundle of fibrils in the tensile load direction. The results of mechanical properties measurements show that the notched Izod impact strengths of foamed PP/TPI blend are two to three times larger than those of the unfoamed counterparts. The PP/TPI blend foam with 5phr TPI content shows the highest impact strength when the foaming temperature is 140°C, which is fivefold increase over that of the neat PP. The enhanced ductility and toughness of PP/TPI foams were found with the increasing foaming temperature. The insert of micro−/nanocellular in PP/TPI blends simultaneously makes the notched impact strength increase significantly, tensile strength decrease, and elongation at break increase obviously, which provides the possibility to combine the higher impact strength and toughness with the advantage of microcellular foaming. POLYM. ENG. SCI., 60:211–217, 2020. © 2019 Society of Plastics Engineers     

Microcellular foaming of chlorosulfonated polyethylene rubber and its kaolin‐filled compounds with supercritical nitrogen

The microcellular foaming of vulcanizates made from chlorosulfonated polyethylene (CSM) rubber and its kaolin‐filled compounds was carried out with supercritical nitrogen. The effects of various curing times, temperatures of the vulcanizates, and kaolin filler contents in the vulcanizates on the prepared foams were studied. The foaming of the vulcanizates with various crosslinking densities revealed the critical effect the crosslinking density of the CSM matrix played on its foaming. A certain sufficient level of crosslinking density was most effective for the foaming of the matrix; a higher crosslinking density led to a decreased cell size, increased cell density, and decreased matrix expansion in the foams. The effect of the crosslinking density was due to its effect on the free volume of the elastomeric matrix, which controlled the gas diffusion from the matrix during the pressure‐release stage of the foaming operation. The incorporation of kaolin decreased the cell size and increased the cell density of the foams; the decreased free volume and the heterogeneous cell nucleation effect of the kaolin contributed to this. The tensile strength of the foams significantly improved with increasing kaolin content in the foams. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45656.     

Physicomechanical,friction, and abrasion properties of EVA/PU blend foams foamed by supercritical nitrogen

Elastomer foams based on EVA, PU, and EVA/PU blends formulated for shoe‐sole applications were prepared by a supercritical N₂ batch foaming process and characterized for physicomechanical, friction and abrasion properties. The blending of EVA with PU was aimed for improving the friction and wear characteristics of the EVA based foams. All of the foams prepared showed spherical cells with closed‐cell morphology and the cell sizes varied with varying the EVA/PU blend ratio and CaCO₃ content of the foams. The properties such as hardness and resilience, friction coefficients and abrasion resistance improved for the EVA/PU blend foams compared to the EVA foam, but their compression set, tensile strength, and tear strength were inferior to the EVA foam. The incorporation of CaCO₃ filler increased density, hardness, tensile strength, and tear strength of the EVA/PU blend foams but decreased resilience, compression set, friction coefficients, and abrasion resistance. The improvement in friction coefficients and wear resistance obtained in the EVA/PU blend foams was significant for shoe‐sole applications. POLYM. ENG. SCI., 2017. © 2017 Society of Plastics Engineers     

Effect of the mixing sequence on the morphology and properties of a polypropylene/polydimethylsiloxane/nano‐SiO2 ternary composite

Ternary composites of polypropylene (PP), polydimethylsiloxane (PDMS) elastomer, and nano‐SiO₂, prepared with three different mixing sequences, were studied for dispersion morphology and its effect on the crystallization of PP and the mechanical properties. The mixing sequence produced a significant effect on the dispersion morphology and, thereby, on the mechanical properties of the composites. A two‐step mixing sequence, in which nano‐SiO₂ was added in the second step to the PP/PDMS binary system, produced a significant encapsulation of nano‐SiO₂ by PDMS, and this, in turn, resulted in the poor modulus and impact strength of the composite. A one‐step mixing sequence of all three components produced a separated dispersion of PDMS and nano‐SiO₂ phases in the PP matrix with the occurrence of a fine band of nano‐SiO₂ particles at the boundaries of the PDMS domains and the presence of some nano‐SiO₂ filler particles inside the PDMS domains. This one‐step mixing sequence produced an improvement in the tensile modulus but a decrease in the impact strength with increasing nano‐SiO₂ content. In the third sequence of mixing, which involved a two‐step mixing sequence through the addition of PDMS in the second step to the previously prepared PP/nano‐SiO₂ binary system, the morphology of the dispersion showed separately dispersed PDMS and nano‐SiO₂ phases with a loose network of nano‐SiO₂ particles surrounding the PDMS domains. This latter series of ternary composites had the highest impact strength and exhibited high shear deformation under tensile and impact conditions. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Crystallization of Polypropylene in PP/PDMS/Nano-SiO2 Ternary Composite

Effect of dispersion morphology, resulting from different mixing sequences used in making ternary composite polypropylene (PP)/poly(dimethylsiloxane) (PDMS)/nano SiO₂, on the crystallization of PP phase is studied. Mixing sequence is found to have significant effect on the dispersion morphology of the ternary composite, which in turn affected the crystallization of the PP matrix of the ternary composite. Crystallization behaviour of PP, studied by the differential scanning calorimetry, is discussed for the effect of different dispersion morphologies on overall crystallization process rate, nucleation rate, crystal size distribution and crystallinity.     

Robust polymer incorporated TiO2-ZrO2 microsphere coatings by electrospraying technique with excellent and durable self cleaning,antibacterial and photocatalytic functionalities

The applications of self-cleaning coatings on large scale are limited due to their poor durability, remnants of hazardous by-products and lack of biocompatibility. We propose to solve this problem by developing TiO₂-ZrO₂ composite-based self cleaning coatings. In order to achieve this task another important aspect was to select biocompatible polymers poly (methyl methacrylate) and pluronic F-127 (PF-127) as they can enhance the self-cleaning capability of TiO₂-ZrO₂ which itself is biocompatible and endowed with anti-bacterial capability. The selection of a preparation technique that could produce coatings mimicking the nature has also been important and hence Electrospraying technique was selected as the processing method. The samples were then characterized using various techniques like field emission scanning electron microscopy, X-ray diffraction, high resolution transmission electron microscopy, Brunauer–Emmett–Teller analysis, and so forth to fathom the interlink between observed properties and morphology. High quality superhydrophobic and superhydrophilic films have been generated and the surfaces were modulated by the addition of tri-block co-polymer which was found to provide swapping of superhydrophobic nature to superhydrophilic nature. The integration of superhydrophobic, superhydrophilic, photocatalytic and antibacterial properties in the prepared microsphere coatings is a unique achievement and may interest those in the quest for self-cleaning materials for antibacterial coatings in mitigating surgical site infections, medical implants, coronary stent surfaces, and so forth.     

Freestanding Ag2S/CuS PVA films with improved dielectric properties for organic electronics

The prime goal of this work is to synthesize free‐standing polyvinyl alcohol (PVA) films doped with Ag₂S, CuS, Ag₂S/CuS alloy, and Ag₂S/CuS nanocomposites through the sol–gel route. The dependence of Ag₂S content in the PVA nanocomposite films on both the real and imaginary parts of the complex permittivity and loss tangent values was examined. An enhanced dielectric constant was achieved with minimum dielectric loss due to the insulating silica layer. By changing the Ag₂S content in Ag₂S/CuS PVA films, the AC conductivity is improved with pure Ag₂S nanoparticles exhibiting highest values of the order of 10^?6?10^?9 S/cm. The Cole–Cole parameters were calculated and the semicircles observed in the plots indicate a single relaxation process. The results suggest that these composite films are potential materials for embedded capacitor applications. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43568.     

Physico‐mechanical properties of NBR/CPVC blend vulcanizates and foams

Foams were prepared from acrylonitrile‐butadiene rubber (NBR)/chlorinated polyvinyl chloride (CPVC) blend compounds using a chemical blowing agent during compression molding. The effect of varying NBR/CPVC blend ratio and the time on the foams were investigated. The curing parameters showed that both the maximum torque and the difference between the maximum and minimum torque decreased with increase of CPVC content. The limiting oxygen index (LOI) of the blend vulcanizate increased with increase of CPVC content, reached up to 30% for the NBR/CPVC blend with blend ratio 50/50. The SEM micrographs of the NBR/CPVC blend indicate semi‐compatibility between the blend phases. The NBR/CPVC foams prepared using a chemical blowing agent, showed closed cell structures, which were uniformly distributed across the blend phases. The average cell sizes increased and foam density decreased with increase of CPVC content. Tensile strength and tear strength of both vulcanizates and foams increased with increase CPVC content. Hardness of the foams increased but resilience of the foams decreased with increase of CPVC content. Density, tensile strength, tear strength, and hardness of the foams increased but resilience decreased when the compression molding time of the foam was increased. J. VINYL ADDIT. TECHNOL., 25:182–188, 2019. © 2018 Society of Plastics Engineers     

Effect of compatibilizer on micromehanical deformations and morphology of dispersion in PP/PDMS blend

Role of maleic anhydride grafted polypropylene (PP‐g‐MAH) in interface modification in polypropylene (PP)/poly(dimethylsiloxane) (PDMS) elastomer blend has been investigated in this article through its effects on morphology of dispersion, micromechanical deformations such as voiding, crazing, shear yielding, fibrillation, and tensile behavior. During tensile deformation, PP/PDMS blend without the compatibilizer showed debonding at the elastomer‐matrix interface and it induced shear yielding and subsequently fibrillation in the matrix. The compatibilizer improved the interfacial adhesion between the PDMS domains and PP matrix, which prevented the debonding at elastomer‐matrix interface and the resulting shear yielding, and fibrillation was absent and rather caused extensive crazing in the matrix. Addition of PP‐g‐MAH reduced the size of dispersed PDMS domains, and narrowed the domain size distribution, which is attributed as an effect of interfacial adhesion produced by PP‐g‐MAH. Stress–strain curve and fibrillation also show similar effect of the interfacial adhesion caused by the compatibilizer. All these observations consistently lead to conclude that PP‐g‐MAH acts as a good compatibilizer for PP/PDMS blend. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007