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111.
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113.
A synthetic strategy based on precursor and prepolymer approaches has been adopted for preparing the functional polymeric
agents with urethane linkage and functional groups such as –CONH–, –COOH, –NH–, C–N, –COOR and C–Cl, that can interact with
the pigment surfaces. The agents were tested for their dispersion capacity. High pigment-loaded (as high as 64%) and solvent-free
stainers with potential applications in low-VOC paints were successfully prepared. The stainers were mixed with two commercial
binder resins—namely epoxy base white and polyurethane metal coat binder resins—to get first paints and their coats on various
substrates such as standard glaze paper, tin and mild steel panels. The paint-specific properties, viz. percentage opacity,
color strength, solvent resistance, adhesion, scratch hardness and salt spray resistance, were measured to adjudge the suitability
of high pigment-loaded coats in industrial applications. The properties measured in general showed improvement in spite of
the increase in the pigment loading. The paint coats resisted not only the xylene, petrol, and lubricating oil attack but
also humidity and salt spray (up to 1000 h of exposure). 相似文献
114.
C. Chandrasekhara Sastry P. Hariharan M. Pradeep Kumar 《Materials and Manufacturing Processes》2019,34(7):814-831
In this research work, an attempt has been carried out to examine (investigate) and study the dry, wet and cryogenic boring of AA 7075 alloy, which is predominantly used in transport applications in defense (aeronautical parts), oceanic and automaker industries. To ensure direct supply of the coolant, and real-time measurement of cutting temperature a modified boring bar is used (modification is carried out using EDM to accommodate placement of a thermocouple to obtain real-time measurement of temperature readings during the boring cycle). It is observed that during cryogenic boring of AA 7075 alloy there is a considerable reduction in the cutting force (Fc), cutting temperature (Tc) and surface roughness (Ra) by 56.16%, 84.70%, 58.98% compared to dry boring and 48.43%, 80.70%, 34.70% compared to wet boring, respectively. Decrease in Fc and Tc leads to a reduction in high stresses at localized points during machining and in turn curtail wear in workpiece and tool. Lubrication provided by cryogenic fluids also plays a sizable role in reduction of Fc and Tc. Reduction in lower Fc and Tc has a glaring effect on the surface characteristics of the hole produced during the boring process. Tool wear is reduced in cryogenic boring by 36.96% and 17.57% compared to dry and wet boring, respectively. Taguchi and ANOVA was carried out which helped in determining feed as an important parameter with respect to Fc and Ra during boring of AA 7075 under dry, wet and cryogenic conditions whereas speed as an important parameter in determining Tc in dry and wet conditions and feed for Tc in cryogenic boring condition. TOPSIS analysis highlighted speed of 770 rpm and feed of 0.055 mm/min as the most closest to ideal solution for all three different cutting conditions. Surface morphology study after boring of AA 7075 highlighted better surface characteristics in cryogenic bored surface compared to dry and wet boring. Roughness measured in AFM for tool used in boring highlighted a decrease in 86.79% and 66.01% in cryogenic boring in juxtaposition with dry and wet boring, respectively. A surge in compressive residual stress is observed in cryogenic bored surface by 10.41% and 3.5% in juxtaposition with dry and wet boring, respectively, highlighting an abatement in tensile residual stress and better workpiece integrity as compared to dry and wet boring conditions. 相似文献
115.
G Ginther RM Edelstein CP Forsyth K Gamarnik AE Kreymer RJ Lipton JM McQuade DM Potter JS Russ L Spiegel DE Johnson D Buchholz LM Cremaldi SW Delchamps HS Mao JL Rosen W Sakumoto RA Schluter SB Sontz C Winter JM Bishop NN Biswas NM Cason L Dauwe J Godfrey VP Kenney P Mooney R Pemper E Rojek RC Ruchti M Sarmiento WD Shephard 《Canadian Metallurgical Quarterly》1987,35(5):1541-1552
116.
V Vijayashree C K Subramaniam R Srinivasan I K Gopalakrishnan PVPSS Sastry J V Yakhmi R M Iyer 《Bulletin of Materials Science》1991,14(3):827-830
Single-phase 2122 samples of thallium and bismuth superconductors were made by the precursor matrix method. The thermopower
of these samples was measured in the temperature range 250 K-T
c
. The thermopower was positive and decreased linearly with increasing temperature aboveT
c
(onset). The exponential enhancement of thermopower seen in the undoped and doped YBCO was not observed in these samples.
The linear variation of thermopower can be explained on the basis of either a two-band model or a narrow band model. 相似文献
117.
Paramasivam Anandakumar Mallina Venkata Timmaraju Ramachandran Velmurugan 《应用聚合物科学杂志》2024,141(4):e54845
Design of automotive components with over-molded short/continuous fiber reinforced thermoplastic composites necessitates understanding of their behavior under extreme outdoor conditions. The short, quasi-isotropic and over-molded short/continuous glass fiber reinforced polypropylene (PP) composite specimens were prepared as per standard and immersed in water until equilibration to study their relative moisture absorption characteristics and consequent mechanical behavior. As the absorbed moisture mostly occupied the interface between fiber and matrix in laminated composite inserts and moisture absorption of short fiber composite core is insignificant, the moisture absorption of over-molded composites is just above 50% of that of laminated composites. The flexural, interlaminar shear and impact behavior of equilibrated composites is primarily governed by the quantum of imbibed moisture of composite materials. Optical analysis of failed moisture equilibrated over-molded specimens showed a marginal delamination between plies of the inserts without any perceptible damage within the short fiber composite similar to dry as molded specimens. 相似文献
118.
Optimization of modern machining processes using advanced optimization techniques: a review 总被引:1,自引:0,他引:1
R. Venkata Rao V. D. Kalyankar 《The International Journal of Advanced Manufacturing Technology》2014,73(5-8):1159-1188
Thorough literature review of various modern machining processes is presented in this paper. The main focus is kept on the optimization aspects of various parameters of the modern machining processes and hence only such research works are included in this work in which the use of advanced optimization techniques were involved. The review period considered is from the year 2006 to 2012. Various modern machining processes considered in this work are electric discharge machining, abrasive jet machining, ultrasonic machining, electrochemical machining, laser beam machining, micro-machining, nano-finishing and various hybrid and modified versions of these processes. The review work on such a large scale was not attempted earlier by considering many processes at a time, and hence, this review work may become the ready information at one place and it may be very useful to the subsequent researchers to decide their direction of research. 相似文献
119.
Dire Dawa, the second largest city of Ethiopia, was facing about the distribution system adopted for supplying clean water. It was being observed that an intermittent type of supply with main and secondary distribution pipes. It was observed that, the current water demand has surpassed the present existing supply about 65%. Hence, in order to provide sufficient quantity and good potable water with continuous (24 X 7) water supply for various sectors of study area: Sabiyan region, Dire Dawa, Ethiopia, was selected. Also, Dire Dawa Water Supply & Sewerage Authority has taken a strong decision in order to validate and examine the existing water distribution network for improved water supply. On the other hand, the main important factor which effects the validation is that the age of pipes and other accessories in present existing network were longstanding. Therefore, to avoid the leakage losses and various problems encountered with the present system, a detailed is study is conducted and the analysis is carried out using EPANET tool to design for continuous water supply. After thorough analysis by considering future concerns, it was suggested that, two GLSRs of each with 2.7 Mm3 capacity may be provided in order to meet the future demands. The tanks are provided at required elevation to ensure that the water flows in all pipes of the network efficiently. Based on the output it was observed that the diameter of pipes from the existing system ought to be revised. Additionally, other parameters which effect the network like frictional losses, velocity of flow in the pipes, residual head and pressure at nodes were also examined thoroughly by the use of different tools like WaterGEMS and Auto CAD in addition to EPANET. 相似文献
120.
M. Venkateswar Reddy K. AmulyaM.V. Rohit P.N. SarmaS. Venkata Mohan 《International Journal of Hydrogen Energy》2014
Synthesis of bioplastics (polyhydroxyalkanoates (PHA)) using Bacillus tequilensis, a newly isolated strain was investigated under aerobic condition using designed wastewater with synthetic acids (SA) and acidogenic fermented food waste (AFW) collected from biohydrogen (H2) producing anaerobic bioreactors as substrates. The isolate showed the ability to grow and accumulate PHA in both the substrates, with simultaneous waste remediation. Higher PHA synthesis was observed with SA (59% dry cell weight) compared to AFW (36% dry cell weight) with good substrate removal (SA, 87%; AFW, 59%). The PHA composition showed presence of co-polymer [P(3HB-co-3HV)] with varying contents of hydroxy butyrate (HB, 80–90%) and hydroxy valerate (HV, 10–15%) in both the substrates. High dehydrogenase activity was observed which leads to the formation of considerable quantity of PHA. AFW from H2 producing reactor as substrate contributes in reducing the production cost of both H2 as well as PHA embedded with waste valorization. 相似文献