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排序方式: 共有4735条查询结果,搜索用时 140 毫秒
71.
Mohammad Mohammadian Maryam Ahmadi Mohammad Reza Khosravi-Nikou 《Petroleum Science and Technology》2017,35(6):608-614
Adsorption of heterocyclic sulfur- and nitrogen-containing compounds by mesostructure adsorbent (MSU-S) and its modified form with cobalt oxide is studied using model fuel. The results of characteristic tests (XRD, N2 adsorption–desorption, FTIR, and SEM) indicate that CoO impregnation causes a negative impact on mesoporous structure, crystalline phase, and particle shape along with a positive effect on surface ion exchange. CoO modification increased the adsorption loadings of DBT and BT to about 33.6% and 45.7%, respectively. For nitrogen compounds adsorption with the model fuel, adsorption loadings of quinoline and carbazole increase by 6.7% and 8.6%, respectively. Data fitting for carbazole, DBT, and BT is achieved better by the Langmuir model than the Freundlich model, and the data of quinoline fitted very well to the Freundlich model for CoO-MSU-S. 相似文献
72.
Knowing compressibility factor (z-factor) values of natural gases is the basis of most petroleum engineering calculations. Shortage of available experimental data for the specified composition, temperature, and pressure conditions encourages researchers to propose efficient equations for calculating z-factor values.
This investigation presents a useful empirical model for determining natural gases compressibility factor values. The advantages of this correlation are that it is explicit in terms of z-factor and the results of calculating compressibility factor values by this method reveal the supremacy of the new equation over the other widely used correlations. 相似文献
73.
A reactive cyclodextrin was synthesised by reacting β‐cyclodextrin with itaconic acid to enable it to fix permanently onto cellulosic materials. Because synthesis is a complicated process that is greatly influenced by many factors, the response surface methodology was applied in this study to optimise production. To investigate the efficiency of the esterification reaction, the amount of carboxyl groups and the double bond content of the end product were measured and employed as the responses. The 3D response surface plots and the contour plots derived from the mathematical models were applied to evaluate the interactive effects of parameters affecting the reaction, such as itaconic acid and catalyst concentrations, material to liquor ratio, temperature and time of reaction. The amount of carboxyl groups and the double bond content of cyclodextrin itaconate (about 175 and 150 meq./100 g CDI, respectively) in the optimum conditions indicated that one to two itaconic acid molecules could react with cyclodextrin according to the esterification reaction. In addition, the presence of the new supplementary groups on cyclodextrin could effect on the aggregation behaviour of this new cyclodextrin derivative as demonstrated by dynamic light scattering and AFM. 相似文献
74.
BACKGROUND: Iron-deficiency anemia is the most prevalent nutritional deficiency worldwide. Iron-deficiency anemia has particular negative consequences on women in their childbearing years, and its prevention is a high priority in most health systems. OBJECTIVE: This interventional study assessed the effect of nutrition education on hematologic indices, iron status, nutritional knowledge, and nutritional practices of high-school girls in Iran. METHODS: Sixty healthy 16- to 18-year-old girls were randomly selected from two high schools in the city of Ahvaz and divided into two equally matched groups, one that received nutrition education, and one that did not. The education group received instruction in face-to-face sessions, group discussions, and pamphlets for 2 months. The control group did not receive any information during the study. Hematologic tests, corpuscular indices, and serum ferritin levels were measured at baseline and after 2 months. Food-frequency questionnaires were administered and histories taken, clinical signs of nutritional deficiencies observed, anthropometric measurements taken, nutritional knowledge tested, practices determined, and lifestyle questionnaires administered to all subjects. RESULTS: There were no statistically significant differences in any baseline characteristics between the two groups. Scores for nutritional knowledge and practices of the education group were significantly higher after two months compared with the baseline (31.4 +/- 6 vs. 24.3 +/- 5.9 points, p < .001, and 31.2 +/- 5 vs. 28.4 +/- 5.7 points, p < .05, respectively). The scores in the control group showed no significant changes from baseline to 2 months. Mean corpuscular volume values were elevated in the education group (p < .001) but not in the control group. However, in the control group, serum ferritin concentrations showed about a 17% drop at the end of the study (p < .004). There were no changes in other hematologic, lifestyle, clinical, or anthropometric data compared with baseline after completion of the study in both groups. CONCLUSION: These findings indicate that nutritional education can improve knowledge of healthy nutrition and lifestyle choices. Focused nutritional education using available resources and correcting current dietary habits in a vulnerable group of young women may result in dietary changes that can ultimately improve iron intake. 相似文献
75.
Effect of gums on viability and β‐galactosidase activity of Lactobacillus spp. in milk drink during refrigerated storage 下载免费PDF全文
Bernice D. Karlton‐Senaye Reza Tahergorabi Valerie L. Giddings Salam A. Ibrahim 《International Journal of Food Science & Technology》2015,50(1):32-40
The viability and β‐galactosidase activity of four Lactobacillus strains in milk drink containing gums during 28 days of refrigerated storage at 4 °C were assessed. The population of Lactobacillus rhamnosus GGB101 and Lactobacillus rhamnosus GGB103 were maintained, whereas the population of Lactobacillus reuteri DSM20016 and Lactobacillus reuteri SD2112 significantly decreased. The recommended level of 6 log CFU g?1 was exceeded for all tested trains throughout storage. The highest viable number of Lactobacillus rhamnosus GGB103 (8.76 ± 0.03 log CFU mL?1) was obtained in the product containing carrageenan–maltodextrin. The addition of guar–locust bean–carrageenan led to 20‐fold increase in the level of β‐galactosidase activity for L. rhamnosus GGB101 (1208 ± 2.12 Miller units mL?1) compared to the control (61 ± 2.83 Miller units mL?1). Our results suggested that gums could be added to milk to improve viability and enhance β‐galactosidase activity of Lactobacillus. 相似文献
76.
Leila Yousefi Mohammad Bagher Habibi Najafi Mohammad Reza Edalatian Dovom Amir Mohammad Mortazavian 《International Journal of Food Science & Technology》2021,56(5):2530-2538
In this study, ultrafiltered (UF) Iranian white cheese made with adjunct cultures including six Lactobacillus isolates (Lactobacillus brevis, L. casei and L. plantarum) from traditional Iranian Motal cheese. The peptide extract (<5 kDa) of cheese samples were assessed for angiotensin-converting enzyme (ACE)-inhibitory activity during ripening (5 °C). Among the strains used, L. brevis KX572382 (M8) was selected because of the greater increase in (ACE)-inhibitory activity in the cheese (P < 0.05). The highest activity of M8 extract was observed on the 28th (71.72%) day of ripening (P < 0.05). Proteolytic activity assessment and RP-HPLC peptide profile of M8 water-soluble extracts (WSEs) indicated the effect of M8 on further protein degradation due to secondary proteolysis. A total of 7 different peptide sequences, previously known in the literature for their ACE-inhibitory activity, were tentatively identified by LC/ESI-MS in 28-day M8 peptide extract. Although the effect of M8 on pH and the proteolysis development in cheese was significant, no adverse effect was observed on the sensory properties. In conclusion, M8 strain can enhance the functional properties of Iranian UF white cheese. 相似文献
77.
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79.
Effect of copper nanoparticles on permeability, physical, and mechanical properties of particleboard
Effects of a 200 ppm nanocopper suspension, with size range from 10 to 80 nm, on the physical and mechanical properties of particleboard made on an industrial scale at the Iran-Choob Factory were studied. Nanocopper suspension was added to the mat at two levels of 100 and 150 ml/kg dry weight wood particles and compared with control boards. Results showed that hot-pressing time was reduced by 5.7 and 3.4 % when 100 and 150 ml of nanocopper were used, respectively. Also, both levels of nanocopper consumption had improving effects on physical and mechanical properties, although in some cases not significant. Permeability was significantly decreased to its lowest value in 150 ml/kg treatment. It can be concluded that 150 ml of nanocopper/kg may be used to improve the physical and mechanical properties, to reduce press time, and to decrease permeability in particleboards. For industrially accepted outcome, 150 ml/kg of nanocopper is recommended. 相似文献
80.
Mojtaba Delfanian Reza Esmaeilzadeh Kenari Mohammad Ali Sahari 《International Journal of Food Properties》2013,16(12):2813-2824
The antioxidation activities of Eriobotrya japonica (Lindl.) fruit peel and pulp extracts were determined using DPPH, β-carotene, and Rancimat methods. Results showed that ethanol-water extract of peel and ethanol extract of pulp had the highest antioxidant activity. Protective effects of extracts in stabilization of soybean oil were tested and compared to tert-butyl hydroquinone by measuring peroxide values, free fatty acids, thiobarbituric acid, oxidative stability, and conjugated dienes and trienes values during storage (65 days at 25°C). Results showed that the ethanol-water extract of peel at 400 ppm exhibited stronger antioxidant activity, but the highest effect was observed in tert-butyl hydroquinone. 相似文献