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1.
Sorption,solubility, and mass changes of hydroxyapatite‐containing composites in artificial saliva,food simulating solutions,tea, and coffee
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The purpose of this study was to evaluate the influence of preparation/storage conditions on the sorption, solubility, and mass changes of new proposed hydroxyapatite‐containing resin‐based composites. Seventy cylindrical samples of composite were prepared according to the ISO 4049 and stored in different storage solutions (distilled water, artificial saliva, 10% ethanol, 3% acetic acid, heptane, tea, and coffee) for 7, 14, and 28 days at 37°C. Principal component analysis and analysis of the variance were used to determine the impact of the preparation and storage conditions (e.g., curing time, storage time, and type of storage solution) on the changes of stability of examined material. Sorption, solubility, and mass changes of examined samples were specified. The tendency of these changes depending on the curing time, storage time, and type of storage solutions were presented. Due to the observed behavior, three groups of storage solutions were distinguished: “aqueous,” acidic, and hydrophobic (“fat”) solutions. Investigated properties changed in different way, characteristic for each of the above groups. No general tendency of the influence of storage and curing time was observed. The type of storage solution has the greatest impact on the sorption, solubility, and mass changes of examined material. The influence of the curing and storage time may be neglected. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 39856. 相似文献
2.
D. W. Rutland 《Nutrient Cycling in Agroecosystems》1991,30(1):99-114
Most fertilizers have some tendency to form lumps or agglomerates (caking) during storage. The mechanism of caking in fertilizers is most often attributed to the formation of salt bridges and/or capillary adhesion. The severity of caking can be influenced by a number of factors, such as chemical composition, moisture content, particle structure, mechanical strength, hygroscopic properties, product temperature, ambient conditions, storage time, and storage pressure. The various methods of reducing or eliminating caking in fertilizers basically involve process control, storage/packaging conditions, and/or addition of anticaking agents.Caking mechanisms, factors that influence caking, and methods of prevention are discussed in this paper. Particular attention is given to the various types of anticaking agents and their modes of action. The paper also provides a fairly comprehensive list of commercially available anticaking agents and their producers. 相似文献
3.
In this study, the rheological parameters as well as Flory–Huggins parameter determined by Inverse Gas Chromatography (IGC) were applied for assessment of the changes occurring during storage of the resole resin and their composites. It was proved that storage of resole and its composites at the low temperature (about 10°C) can slow significantly the process of their aging. Main idea of research was to determine time dependence of rheological properties for resole resin. These data should enable to extend shelf life of resin containing products. The rheological properties of samples were studied by the determination of flow curve. Share rate was changed from 10 to 500 1/s. Samples were examined in following intervals (increasing storage time): immediately after preparing the sample and then after storage, respectively: after two, four, eight, and twelve weeks. To extend shelf life of resin, it was mixed with different additives: zeolite Micro 20, Mg(OH)2, PAF, synthetic zeolites: sodium form Z1, hydrogen form Z2. Flory–Huggins parameter determined by use of IGC let to assess physicochemical changes occurring in resole and its composites during storage. IGC turned out to be more sensitive method for assessment of changes occurring during resin aging than rheological measurements. FTIR technique was used to assess chemical changes occurring during resoles compositions storage. It indicated that oxidation reaction can occur during resoles composite aging. 相似文献
4.
J. M. Snyder T. L. Mounts R. K. Holloway 《Journal of the American Oil Chemists' Society》1991,68(10):744-747
Soybeans were microwaved to inactivate enzymes and prevent oil deterioration during storage. Microwave time was varied from
4 to 10 min, in 2-min increments, and the treated and control soybeans were stored for 8 weeks at 40°C. Damage was monitored
by analysis of peroxide value and free fatty acid content of the extracted oil and by volatile analysis of the full-fat meal
and extracted oil. Volatiles were measured by multiple headspace extraction, and the formation of hexanal was monitored in
both oil and meal. During storage of the control beans, peroxide value increased from 0.41 to 1.20 meq/kg, hexanal concentration
changed from 29 to 94 ppb and free fatty acid content increased from 0.4 to 1.7%. Oils extracted from soybeans that were microwaved
for 4 or 6 min had peroxide values of about 1 meq/kg and hexanal concentrations of 39–44 ppb after storage, indicating partial
inactivation of lipoxygenase enzymes. However, soybeans that were microwaved for 8 min or more tended to oxidize during storage
to a greater extent than the control soybeans, showing higher peroxide values and greater formation of hexanal in the samples.
This suggests that soybeans microwave-treated in excess of 8 min are heat-damaged and susceptible to deterioration during
storage. Free fatty acid content of the oils from all of the microwave-treated soybeans was about 0.4% initially, and did
not increase with storage, indicating inactivation of hydrolytic enzymes.
The mention of firm names or trade products does not imply that they are endorsed or recommended over other firms or similar
products not mentioned. 相似文献
5.
Vinyl ester resin: Rheological behaviors,curing kinetics,thermomechanical, and tensile properties
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Xi Zhang Vahid Bitaraf Suying Wei Zhanhu Guo Xi Zhang Suying Wei Henry A. Colorado 《American Institute of Chemical Engineers》2014,60(1):266-274
The effects of isothermal temperature on the curing extent, gel time, dynamic rheological behaviors, and mechanical properties of vinyl ester resins (VERs) were systematically studied. Although, the curing extent was observed increase with increasing the operating temperature, the study of residual heat of cured VERs indicated that the final curing extent depended on the postcuring process. The values of shear storage and loss modulii at gel point were observed to decrease with increasing both the isothermal temperature and heating rate, which were associated with the formation of microgels during the gelation process. With increasing isothermal temperature and heating rate, the microgel did not have enough time to grow well, causing a reduced shear storage and loss modulii at the gel time. The storage and loss modulii of the cured VERs were also studied and shown that with temperature increased to the glass transition, both modulii were first decreased and then increased. © 2013 American Institute of Chemical Engineers AIChE J, 60: 266–274, 2014 相似文献
6.
《Journal of Adhesion Science and Technology》2013,27(4):351-359
Surfaces of medical grade silicone rubber (Q7-4750, Dow Corning) were modified by repeated (six times) RF plasma treatments using various discharge gases: oxygen, argon, carbon dioxide, and ammonia. The treated samples were stored for a period of 3 months in ambient air, water, or liquid nitrogen. Subsequently, the temporal behavior of the effects of the plasma treatment on the physicochemical surface properties of the silicone rubber was investigated using water contact angle measurements and X-ray photoelectron spectroscopy (XPS). Hydrophobic recovery during 3 months storage in ambient air was considerable and nearly complete for all four plasmas used. Hydrophobic recovery was almost completely suppressed during storage in liquid nitrogen, and only a minor increase of around 10° in advancing water contact angle was observed for all four plasma treatments. Also during storage of treated samples in water, hydrophobic recovery was minimal and initiated again by returning the treated samples to ambient air. XPS analyses showed that argon, carbon dioxide, and ammonia plasma-treated silicone rubber all had increased carbon percentages at the expense of oxygen and silicon after storage in water, or in liquid nitrogen, compared with after storage in ambient air. Interestingly, the carbon content of oxygen plasma-treated silicone rubber decreased during storage in water, or in liquid nitrogen, compared with storage in ambient air, while its oxygen and silicon percentages increased. 相似文献
7.
The individual tocopherols present in almond, pecan and macadamia nuts were determined by HPLC. Changes in tocopherol content
during 16-months' storage at 30°C and 55% relative humidity were related to keeping quality. The large amount of total tocopherols,
mainly α-tocopherol, in almonds accounted for their good storage ability. Pecan nuts with less total tocopherols and mainly
γ-tocopherol became rancid after 4 months' storage and macadamia nuts, with practically no tocopherols, were rancid after
2 months' storage. Total tocopherol content decreased in all nuts during storage, possibly as a result of its inhibitory function
during auto-oxidation. 相似文献
8.
《塑料、橡胶和复合材料》2013,42(1):1-10
AbstractDynamic mechanical analysis of precipitate CaCO3 filled, closed cell microcellular ethylene–octene copolymer vulcanisates has been studied as a function of temperature and double strain amplitude. Experiments were carried out over the temperature range – 100 to 100°C. Strain dependent isothermal dynamic mechanical analysis was performed for double strain amplitude 0·09–5%. The log of storage modulus bears a simple relationship with the log of density for both solid and closed cell microcellular rubber. The slope of the line is found to be temperature dependent. The relative storage modulus decreases with decreasing relative density. The eect of blowing agent and filler loading on storage modulus and loss tangent were also studied. Cole–Cole plots of microcellular vulcanisates show a circular arc relationship with density. Plots of loss tangent against storage modulus were found to exhibit a linear relationship. Hysteresis and strain work also bear a linear relationship. 相似文献
9.
Scope This standard specifies the technical requirement of the packing marking transportation storage of shaped refractory products.…… 《中国耐火材料》2007,16(4):39-41
1 Scope
This standard specifies the technical requirement of the packing, marking, transportation and storage of shaped refractory products. 相似文献
This standard specifies the technical requirement of the packing, marking, transportation and storage of shaped refractory products. 相似文献
10.
Ling-Zhi Cheong Chin-Ping Tan Kamariah Long Mohd. Suria Affandi Yusoff Oi-Ming Lai 《Journal of the American Oil Chemists' Society》2009,86(8):723-731
Physicochemical, textural and viscoelastic properties of palm diacylglycerol (PDG) bakery margarines (DOS720, DOS721 and DOS711)
and commercial margarine (CM) throughout a 3-month storage period were evaluated and compared. All the margarines had significant
(P < 0.05) increments in slip melting point (SMP), solid fat content (SFC) and hardness during storage with CM having the highest
overall increment followed by margarines DOS711, DOS 721 and DOS720. The smaller increments are mainly due to the ability
of PDG to delay polymorphic transformation from β′ to β form. In terms of viscoelastic properties, all margarines had a higher
degree of firmness which may probably be due to rearrangement of the fat crystals into a three-dimensional scaffolding network
upon storage. In terms of melting behavior, storage has no effects on all margarines with the exception of margarine DOS711.
The melting behavior of margarine DOS711 displayed a probability of oil exudation during storage. As for polymorphic transformation,
CM had the earliest polymorphic transformation with only β crystals after 8 weeks of storage. PDG bakery margarines managed
to retard the transformation to more than 10 weeks of storage for DOS711 and 12 weeks of storage for DOS720 and DOS721. 相似文献
11.
Søren O. Petersen Nadia Dorno Sabine Lindholst Anders Feilberg Jørgen Eriksen 《Nutrient Cycling in Agroecosystems》2013,95(1):103-113
Manure storage contributes significantly to greenhouse gas (GHG), NH3 and odour emissions from intensive livestock production. A pilot-scale facility with eight 6.5-m3 slurry storage units was used to quantify emissions of CH4, N2O, NH3, and odorants from pig slurry during winter and summer storage. Pig slurry was stored with or without a straw crust, and with or without interception of precipitation, i.e., four treatments, in two randomized blocks. Emissions of total reduced S (mainly H2S) and p-cresol, but not skatole, were reduced by the straw crust. Total GHG emissions were 0.01–0.02 kg CO2 eq m?3 day?1 during a 45-day winter storage, and 1.1–1.3 kg CO2 eq m?3 day?1 during a 58-day summer storage period independent of storage conditions; the GHG balance was dominated by CH4 emissions. Nitrous oxide emissions occurred only during summer storage where, apparently, emissions were related to the water balance of the surface crust. An N2O emission factor for slurry storage with a straw crust was estimated at 0.002–0.004. There was no evidence for a reduction of CH4 emissions with a crust. Current Intergovernmental Panel on Climate Change recommendations for N2O and CH4 emission factors are discussed. 相似文献
12.
13.
C. Na Ranong M. Höhne J. Franzen J. Hapke G. Fieg M. Dornheim N. Eigen J. M. Bellosta von Colbe O. Metz 《化学工程与技术》2009,32(8):1154-1163
In the framework of the EC project STORHY (Hydrogen Storage for Automotive Applications), the prototype of a solid storage tank for hydrogen based on sodium alanate was developed. A storage tank containing 8 kg sodium alanate was designed and manufactured with the objective of fast refueling. To obtain the optimum design of the storage tank a simulation tool was developed and validated by experiments with a laboratory‐scale tubular reactor. Application of the simulation tool to different storage concepts and geometries yielded the final design. The chosen concept is modular, enabling simple scale‐up. This is the basis for the future development of fuel cell vehicle storage tanks containing 5 kg of hydrogen. 相似文献
14.
M Giovanni HL Poh A Ambrosi G Zhao Z Sofer F Šaněk B Khezri RD Webster M Pumera 《Nanoscale》2012,4(16):5002-5008
Metal decorated graphene materials are highly important for catalysis. In this work, noble metal doped-graphene hybrids were prepared by a simple and scalable method. The thermal reductions of metal doped-graphite oxide precursors were carried out in nitrogen and hydrogen atmospheres and the effects of these atmospheres as well as the metal components on the characteristics and catalytic capabilities of the hybrid materials were studied. The hybrids exfoliated in nitrogen atmosphere contained a higher amount of oxygen-containing groups and lower density of defects on their surfaces than hybrids exfoliated in hydrogen atmosphere. The metals significantly affected the electrochemical behavior and catalysis of compounds that are important in energy production and storage and in electrochemical sensing. Research in the field of energy storage and production, electrochemical sensing and biosensing as well as biomedical devices can take advantage of the properties and catalytic capabilities of the metal doped graphene hybrids. 相似文献
15.
L. J. Ashworth Jr. J. L. McMeans B. R. Houston M. E. Whitten C. M. Brown 《Journal of the American Oil Chemists' Society》1971,48(3):129-133
In central California, neither fungal infections nor aflatoxins are significant problems in cottonseed during the receiving
and storage seasons. However, in southern California, the 1967 harvest contained a relatively high percentage of seed which
were invaded before harvest by fungi, includingAspergillus flavus. Seed infection and concentrations of aflatoxins in seed increased significantly during the time between harvest and storage
in southern California. For a short time during storage, seed infection byA. flavus increased because of the moisture the seed received late in the season; however, aflatoxin concentrations in seed did not
increase in storage. The aflatoxin content of the seed removed from storage was a reflection of the relative amount of aflatoxins
the seed contained when they were received for storage. In 1967, the conditions that existed in the large, densely packed
seed pile did not favor accummulation of aflatoxins in seed, even thoughA. flavus was active. 相似文献
16.
电化学储能器件的性能很大程度上决定于其电极材料。碳材料具有来源广泛、化学稳定性好、易于调控、环境友好等优点,被广泛应用于各类能量存储系统,但仍存在能量密度低、倍率性能差等问题。本文从碳材料孔结构调控、杂原子掺杂、与金属氧化物复合三个角度,综述了构建高性能碳基储能材料的设计合成策略,介绍了其在锂/钠离子二次电池、超级电容器等领域的研究进展,对几种方法策略的优缺点进行了总结,并对未来的研究方向进行了展望。本文对高性能碳基储能电极材料的设计开发具有积极意义。 相似文献
17.
18.
Dynamic mechanical analysis of carbon black loaded solid and closed-cell microcellular ethylene-propylene-diene (EPDM) vulcanizates was studied at four frequencies of 3.5, 11, 35, and 110 Hz and temperatures from −100 to 150°C. A plot of the log of the storage modulus bears a linear relationship with the log of density for solid as well as closed-cell microcellular rubber. The slope of the line is found to be temperature-dependent. The relative storage modulus decreases with decrease in the relative density. It was also observed that the storage modulus and tan δ are both frequency- and temperature-dependent. The storage modulus results are superposed to form master curves of the modulus vs. Iog temperature-reduced frequency, using shift factors calculated by the Arrhenius equation. Strain-dependent isothermal dynamic mechanical analysis was carried out for DSA varying from 0.07 to 5%. The effect of blowing agent loading on the storage modulus (E′) and loss tangent (tan δ) were also studied. Cole-Cole plots of microcellular rubber shows a circular arc relationship with the density. Plots of tan δ against E′ were found to exhibit a linear relationship. © 1996 John Wiley & Sons, Inc. 相似文献
19.
Multifunctionalization of novolac epoxy resin and its influence on dielectric,thermal properties,viscoelastic, and aging behavior
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In this article, novolac epoxy was functionalized using p‐hydroxybenzoic acid as pendent groups, which offered weak acidic environment and were cured with methyl etherified amino resin (HMMM). Its chemical structure was characterized by Fourier transform infrared (FT‐IR), 1H nuclear magnetic resonance (1H NMR) and differential scanning calorimeter (DSC). To comprehensively investigate its performance, HMMM was used as a curing agent. The modified epoxy exhibited higher storage modulus, lower thermal expansion coefficient, better moisture resistance, better resistance to degradation and lower dielectric constant. Furthermore, the aging behavior was investigated using dynamic mechanical analysis and scanning electron microscopy, which showed that the activation energy of glass transition increased after aging and cured MDEN was more difficult to age. Moreover, the relation between storage modulus and curing rate was established; the low curing rate of MDEN decreased the growth rate of storage modulus and reduced the internal stress, which was beneficial for processing. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40157. 相似文献
20.
Haoduo Yang Ying Dong Dongying Wang Xuede Wang 《European Journal of Lipid Science and Technology》2023,125(1):2200099
The study aims to compare the differences in the oxidative stability, sensory properties, and volatile compounds during accelerated storage of pepper aromatized sunflower oil (PASO) samples prepared by maceration method (PASO-M), co-pressing method (PASO-C), and direct addition method (PASO-A), respectively. The results exhibit that their oxidative stability is in the relative order: PASO-A > PASO-C > PASO-M. Meanwhile, the PASO-A sample is the most preferable aromatized sunflower oil by consumers according to sensory analysis. In addition, a total of 83 volatile compounds are identified in the three PASO samples during the storage, and the principal component analysis (PCA) shows that their volatile compounds are quite different at the initial stage of the storage. Still, they are similar among each other from the middle of storage period. As consequence, the aromatized sunflower oil sample prepared by the direct-addition method during the storage possesses better oxidative stability and sensory attributes, and there is not much difference among their volatile compounds, indicating that the aromatized sunflower oil prepared by direct-addition method can be developed as promising aromatized sunflower oil. Practical applications: This study shows that aromatization increases oxidative stability and sensory properties of sunflower oil. By this way some sunflower oils with special sensory properties are obtained: special smell and taste, special color, etc. These peppers aromatized sunflower oils can be used to increase taste and smell in some dishes. For example, they can be used in some salads and some roast meats to give more taste and color. 相似文献