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排序方式: 共有912条查询结果,搜索用时 15 毫秒
131.
In this work, the mathematical-numerical model of carbonation process in reinforced concrete (RC) structures, which has been developed by the authors, is applied to different cases of study to take into account the probabilistic nature of durability assessment procedure even if within the framework of a rough and ready approach. In particular, the aim of this Part I of the work is to study how the variability of the parameters defining the differential equations in the model influence the assessment of the corrosion initiation time of RC structure. Comparison with experimental results and numerical simulations are undertaken in Part II of this work. 相似文献
132.
Comparison between enzymatic and chemical interesterification of high oleic sunflower oil and fully hydrogenated soybean oil
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133.
Chen J Tokonami S Sorimachi A Takahashi H Falcomer R 《Radiation protection dosimetry》2008,130(2):253-256
Ottawa is the capital city of Canada. In the previous crossCanada radon survey, Ottawa was not included. There is greatinterest to know radon level as well as thoron concentrationin Ottawa homes. Therefore, radon/thoron discrimination detectorsdeveloped at the National Institute of Radiological Sciencesin Japan were deployed in 93 houses for a period of 3 months.As expected, thoron is present in Ottawa homes. Radon concentrationsranged from 8 to 1525 Bq m–3 while thoron concentrationsvaried from 5 to 924 Bq m–3. The arithmetic mean of radonand thoron concentrations were found to be 110 ± 168and 56 ± 123 Bq m–3, respectively. 相似文献
134.
Edmilson Costa Teixeira Renato do Nascimento Siqueira 《Canadian Metallurgical Quarterly》2008,134(10):851-859
The analysis of residence time distribution functions originating from tracer studies is one of the main tools for the assessment of hydraulic performance in water and wastewater treatment units. In order to simplify the analysis, hydraulic indexes extracted from these functions are normally used. In general, these indexes are divided into two categories: short circuit and mixing indicators. However, some indexes may be related to more than one physical phenomenon (i.e., short circuit, mixing, recirculation, dead zones), leading to erroneous interpretation. In this work their capability to evaluate short-circuit and mixing levels in water and wastewater treatment units is assessed. Among the indexes analyzed, t10, which is the time necessary for 10% of the tracer to leave the unit, is recommended as a short-circuit indicator and the dispersion index (σ2) and the Morril index as mixing indicators, depending on the mixing level. 相似文献
135.
136.
Lukac H Amrein TM Perren R Conde-Petit B Amadò R Escher F 《Journal of food science》2007,72(1):C033-C038
ABSTRACT: The influence of roasting conditions on the acrylamide content and on the color of roasted almonds of 3 cultivars was investigated. The temperature inside the almond kernel, the water content, the color, and the acrylamide content were determined at different roasting temperatures and times. The formation of acrylamide started only when the kernel temperature had exceeded approximately 130 °C. The activation energy for the acrylamide formation during the roasting of almonds was 123 kJ·mol−1 . The color as measured by the degree of brightness correlated well with the acrylamide content as acrylamide content increased with increasing darkness. Therefore, control of roasting temperature presents the critical factor for limiting the acrylamide concentration in the final product. At constant roasting conditions, almonds with higher initial moisture content contained less acrylamide after roasting, which is probably due to the influence of moisture on the development product temperature during roasting. 相似文献
137.
Bárbara Biduski Jarine Amaral do Evangelho Karina Oliveira Lima Shanise Lisie de Mello El Halal Elessandra da Rosa Zavareze Alvaro Renato Guerra Dias Vânia Zanella Pinto 《Starch - St?rke》2024,76(1-2):2200209
Using non-conventional starch can benefit the industry since it can present different properties. It also can lead to new properties upon physical modification, which improves its derivate film properties. Therefore, the aim of this work is to evaluate the heat–moisture treatment (HMT) on pinhão starch and its effectiveness in film properties. After isolation using water as a solvent, the pinhão starch is treated by HMT for 16 h at 110 °C. Native and HMTed starches are used to produce biodegradable films. Pinhão starch and starch films chemical and physical properties are properly characterized. The HMT causes some changes in short-range ordered structures, reduces the relative crystallinity, and shifts the pinhão starch from C-type to A-type. Also, HMT decreases the peak viscosity and the breakdown, and improves thermal stability. These starch changes upon HMT reduces water vapor permeability, increases tensile strength, and elongation at the break of pinhão starch films. Desirable changes in starch and film properties are achieved by physically modifying pinhão starch using HMT, which is a promising alternative to chemical modifications. 相似文献
138.
Luca Maria Chiesa Maria Nobile Renato Malandra Davide Pessina Giuseppe Federico Labella 《Food additives & contaminants. Part A, Chemistry, analysis, control, exposure & risk assessment》2018,35(5):959-971
Reviewing the presence of contaminant residues is important both for food safety and for monitoring of environmental pollution. Here, the occurrence of 6 polychlorinated biphenyls (PCBs), 15 organochlorine pesticides (OCPs), 7 polybrominated diphenyl ethers (PBDEs), 4 polycyclic aromatic hydrocarbons (PAHs) and 17 perfluoroalkyl substances (PFASs) was evaluated in mussels and clams. A liquid chromatography-high resolution mass spectrometry (HPLC-HRMS) and an innovative QuEChERS extraction followed by gas chromatography-tandem mass spectrometry (GC-MS/MS) methods were developed, validated and applied. We demonstrate good linearity, repeatability and accuracy of these methods, confirming that they are suitable for the analyses of mollusc samples. The prevalence of PCBs, OCPs and PAHs was higher in mussels than in clams. For PFASs, contamination was higher in clams than in mussels. The samples were all compliant with the regulations, and, for the compounds without legislative limits, a risk assessment confirmed that the values were lower than the tolerable intakes. 相似文献
139.
140.
Amilcare Pozzi Renato Tognaccini 《International Journal of Heat and Mass Transfer》2011,54(17-18):4019-4027
The exact analytical solution of the unsteady impulsive Thermo-Fluid Dynamic field arising in a two-dimensional channel with thick solid walls is presented when the thermal field in the fluid is coupled with the thermal field in the solid (conjugated heat transfer). The cases studied in this paper depend on the boundary conditions imposed on the unwetted sides of the channel walls: assigned temperature and adiabatic condition. Moreover the case of a given heat loss at the unwetted wall is also considered in an appendix. The temperature and heat flux at the solid–fluid interface are analyzed as function of time and of the nondimensional parameters governing the problem. 相似文献