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101.
An investigation of the gasoline permeation resistance of the as‐blow‐molded and annealed polyethylene, polyethylene (PE)/polyamide (PA), and polyethylene/modified polyamide (MPA) bottles is reported. The gasoline permeation resistance improves dramatically after blending PA and MPA barrier resins in PE matrices during blow‐molding, and the order of barrier improvement corresponds to the order of barrier improvement of the barrier resins added in PE. Somewhat unexpectedly, the gasoline permeation rates of the annealed PE and/or PE/PA bottles annealed at 90°C or higher temperatures increase significantly with the annealing temperature and time. On the contrary, the gasoline permeation resistance of the annealed PE/MPA bottles increase significantly as the annealing temperature and/or time increase. For instance, the gasoline permeation rate of the PE/MPA bottle annealed at 120°C for 32 h is about 190 times slower than that of the as‐blow‐molded PE bottle. Further investigations found that, after blending the MPA and PA barrier resins in PE matrices, the relatively nonpolar hydrocarbon components present in the gasoline fuels were significantly blocked, without permeation during the permeation tests, in which the as‐blow‐molded PE/MPA bottle inhibited the permeation of hydrocarbon components more successfully than did the as‐blow‐molded PE/PA bottle. In contrast, the amounts of polar components that permeated through the as‐blow‐molded PE/PA and PE/MPA bottles were very small and about the same as the amount that permeated through the as‐blow‐molded PE bottle. Possible mechanisms accounting for these interesting behaviors are proposed in this study. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2827–2837, 2001 相似文献
102.
Silicone membranes to inhibit water uptake into thermoset polyurethane shape‐memory polymer conductive composites
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Electroactive shape memory polymer (SMP) composites capable of shape actuation via resistive heating are of interest for various biomedical applications. However, water uptake into SMPs will produce a depression of the glass transition temperature (Tg) resulting in shape recovery in vivo. While water actuated shape recovery may be useful, it is foreseen to be undesirable during early periods of surgical placement into the body. Silicone membranes have been previously reported to prevent release of conductive filler from an electroactive polymer composite in vivo. In this study, a silicone membrane was used to inhibit water uptake into a thermoset SMP composite containing conductive filler. Thermoset polyurethane SMPs were loaded with either 5 wt % carbon black or 5 wt % carbon nanotubes, and subsequently coated with either an Al2O3‐ or silica‐filled silicone membrane. It was observed that the silicone membranes, particularly the silica‐filled membrane, reduced the rate of water absorption (37°C) and subsequent Tg depression versus uncoated composites. In turn, this led to a reduction in the rate of recovery of the permanent shape when exposed to water at 37°C. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41226. 相似文献
103.
Tan Chee Hau Yap Hwa Jen Musa Siti Nurmaya Chang Siow Wee Sivadas Chandra Sekaran Hisaburi Ahmad Syazwan Liew Kan Ern Ismail Ahmad Humaizi Baharudin Luqman Hakim 《Journal of Mechanical Science and Technology》2021,35(9):4115-4123
Journal of Mechanical Science and Technology - Facility layout planning (FLP) has an important role in manufacturing industries. There are few approaches to solve FLP such as procedural,... 相似文献
104.
Meng‐Jen Chen Yu‐Chi Wu Guo‐Tsair Liu Jong‐Fang Chen 《International Journal of Numerical Modelling》2015,28(1):65-77
In Taiwan, the sales revenues of power generation from incinerator power plants with heat recovery power generation sold to the power company were up to NT$4.5bn, making the incinerator power generation play an important role in reduction of impact on environment and substitution of energy in power generation. Studying the dynamic behavior of incinerator power systems under output power variation is thus an essential task for the scheduling, operation, and expansion of incinerator power plants, such as, for cooperating with a scheduling program based on pricing signals to capture energy trading timing economically and to operate the incinerator power system securely. Although there are many studies on incinerator power generation, they seldom discuss the power generation system characteristics. In this paper, mathematical dynamic models for a distributed incinerator power system were derived and implemented using Matlab/Simulink, and dynamic characteristics of the system were further simulated and discussed under two operating modes: increment and decrement of power generation. These developed models can provide dynamic characteristics for these two modes, serving as an important analytic tool for cooperating with a scheduling program based on pricing signals to capture energy trading timing economically and to operate the incinerator power system securely. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
105.
Ming‐Shu Kuo Shinn‐Jen Chang Ping‐Hsun Hsieh Yuan‐Chang Huang Chia‐Chen Li 《Journal of the American Ceramic Society》2016,99(2):445-451
This article discusses the appropriate dispersant for titania (TiO2) nanopowder in organic‐based suspensions. Four types of oleyl‐based dispersants, namely, oleyl alcohol, oleic acid, oleylamine, and oleyl phosphate, which have the functional groups hydroxyl (–OH), carboxyl (–COOH), amino (–NH2), and phosphorous [–P(=O)(OH)2], respectively, were compared for their ability to disperse TiO2. Experimental results for zeta potential, adsorption, FT‐IR spectroscopy, and rheology, as well as theoretical calculations, indicate that dispersants with –P(=O)(OH)2 and –NH2 were more efficient than those with –COOH or –OH. The primary reason for this difference is related to the different interactions of TiO2 with various dispersants and to different dispersion mechanisms. In addition to the major functional groups, –OH in the chemical structure of dispersants was important, as it might have other effects such as destabilization of the suspensions. 相似文献
106.
Toward multiple maximum power point estimation of photovoltaic systems based on semiconductor theory
Jen‐Cheng Wang Yu‐Li Su Kun‐Chang Kuo Jyh‐Cherng Shieh Joe‐Air Jiang 《Progress in Photovoltaics: Research and Applications》2015,23(7):847-861
Environmental conditions, such as temperature, non‐uniform irradiation, and solar shading, deeply affect the characteristics of photovoltaic (PV) modules in PV‐assisted generation systems. Several local maximum power points (MPPs) are found in the power–voltage curve of PV systems constructed by series/parallel‐connected PV modules under partially shaded conditions. The characteristics of PV systems change unpredictably when multiple MPPs occur, so the actual MPP tracking (MPPT) becomes a difficult task. Conventional MPPT methods for the PV systems under partially shaded conditions cannot quickly find the actual MPP such that the optimal utilization of PV systems cannot be achieved. Based on the p–n junction semiconductor theory, we develop a multipoint direct‐estimation (MPDE) method to directly estimate the multiple MPPs of the PV systems under partially shaded conditions and to cope with the mentioned difficulties. Using the proposed MPDE method, the multiple MPPs of the PV systems under partially shaded conditions can be directly determined from their irradiated current–voltage and power–voltage characteristic curves. The performances of the proposed MPDE method are evaluated by examining the characteristics of multiple MPPs of PV systems with respect to different shading strengths and numbers of the shaded PV modules and also tested using the field data. The experimental results demonstrate that the proposed MPDE method can simply and accurately estimate the multiple MPPs of the PV systems under partially shaded conditions. The optimization of MPP control models and the MPPT for PV systems could be achieved promisingly by applying the proposed method. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
107.
Miniemulsion polymerization is usually conducted by a two-stage process, miniemulsion and polymerization, where the reactants are first processed using a high shearing machine, then transferred to a reactor to polymerize with magnetic stirring. However, the particles size distributions obtained usually are broad and skewed to small sizes owing to micelle and homogeneous nucleation in the aqueous solution. In this study, a saw-toothed blade mixer was successfully used for miniemulsion polymerization with a rotating rate over 500 rpm. The addition sequence of the components also affected the miniemulsion process in this system. The best result was obtained when the surfactant and cetyl alcohol were first dissolved in water and then the styrene was mixed in. Furthermore, a fast dissociated redox initiator system (cumene hydroperoxide/Fe2+/ethylenediaminetetraacetic acid-disodium salt/sodium formaldehyde sulfoxylate) was used to prepare miniemulsion polymer and monodisperse polystyrene. © 1996 John Wiley & Sons, Inc. 相似文献
108.
The effectiveness in the year of application of three phosphorus fertilizers, superphosphate, Christmas Island C-grade ore, and 500°C calcined Christmas Island C-grade ore (Calciphos), was measured for 5 consecutive years in a field experiment on a lateritic soil. The residual value of the phosphorus fertilizers was also measured for 6 years. Dry matter production of subterranean clover-based pasture and bicarbonate extractable soil phosphorus were used as indicators of fertilizer effectiveness.Despite the use of very large amounts of C-grade ore and Calciphos, the plateau of the pasture yield versus fertilizer applied curve for these fertilizers did not reach the yield plateau achieved with superphosphate in either the short or long term.C-grade ore and Calciphos were 3% and 8% as effective as superphosphate for dry matter production in the year of application. Relative to superphosphate applied in the current year the effectiveness of superphosphate decreased by about 70% between the first and second year after application and decreased by a further 14% from year 3 to year 6. C-grade ore and Calciphos remained about 2% and 9% as effective as currently applied superphosphate each year.The residual value of superphosphate as measured by bicarbonate-extracted soil phosphorus decreased by about 60% from year 2 to year 7. The residual value of Calciphos was very low for year 2, doubled from year 2–4 and thereafter decreased gradually to its original value by year 7. The residual value of C-grade ore was extremely low throughout the experiment. Thus after year 2, compared to pasture yield, bicarbonate extracted soil phosphorus overestimated the residual value of superphosphate and calciphos.It follows that neither C-grade ore or Calciphos are suitable replacement fertilizers for superphosphate for use on pastures growing on lateritic soils in south-western Australia. 相似文献
109.
A microporous composite polymer membrane composed of poly(vinyl alcohol) (PVA) and poly(vinyl chloride) (PVC), was prepared by a solution casting method and a partial dissolution process. The characteristic properties of microporous PVA/PVC composite polymer membranes containing 2.5-10 wt.% PVC polymers as fillers were characterized by thermogravimetric analysis (TGA), X-ray diffraction (XRD), scanning electron microscopy (SEM), capillary flow porometry (CFP), micro-Raman spectroscopy, dynamic mechanical analyzer (DMA) and the AC impedance method. The electrochemical properties of a secondary Zn electrode with the PVA/PVC composite polymer membrane were studied using the galvanostatic charge/discharge method. The PVA/PVC composite polymer membrane showed good thermal, mechanical and electrochemical properties. As a result, the PVA/PVC composite polymer membrane appears to be a good candidate for use on the secondary Zn electrodes. 相似文献
110.
Preparation and properties of polyethylene terephthalate/polyethylene/near infrared reflective pigment composites
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Polyethylene terephthalate/high density polyethylene (PET/HDPE) composites containing a near infrared reflective (NIR, nickel antimony titanium yellow rutile) pigment was prepared using ethylene‐glycidyl methacrylate‐vinyl acetate (EGMA‐VA) as a compatibilizer to increase the infrared reflection of PET/HDPE and limit the thermal heat accumulation in light of environmental and energy conservation concerns. HDPE was premixed with NIR to form N‐HDPE masterbatch. A good interfacial bonding between PET matrix and HDPE dispersed phase with the help of compatibilizer was confirmed through Fourier transform‐infrared spectra, scanning electron microscopy, and torque rheometer. For PET/N‐HDPE composites, the major X‐ray diffraction peaks and melting behaviors remained unchanged, indicating the limited alternation of crystalline structure for the composite systems with or without compatibilizer. The observed increment in the crystallization temperature of PET for the investigated PET/N‐HDPE composites was mainly due to the nucleation role of both inorganic NIR and HDPE. Tensile strength and elongation at break for compatibilized cases at various N‐HDPE contents conferred higher values than those of the corresponding counterparts without compatibilizer. Yet, Young's modulus for compatibilized systems was about 40% lower than that for systems without compatibilizer, attributed to the rubbery nature of EGMA‐VA. With the inclusion of NIR into HDPE to form PET/N‐HDPE composites with or without EGMA‐VA compatibilizer, the values of reflectance increased to a great degree. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40830. 相似文献