Ni catalyst promotion of a Cis-selective Pd catalyst for canola oil hydrogenation

A Ni catalyst was added to a cis-selective Pd catalyst in an attempt to further improve the Pd catalyst's cis-selectivity and activity for canola oil hydrogenation. The system was tested under reaction conditions known to be suitable for cis-selective hydrogenation with the Pd catalyst (50 ppm Pd, 70 °C, and 5.2 MPa). Although inactive on its own under these conditions, the addition of 100 ppm Ni increased the hydrogenation activity (from 2.12 to 2.49 10⁻² min⁻¹). Further addition of Ni up to 1000 ppm resulted in no further improvements in activity. The trans isomer contents of the oils hydrogenated with Pd and the Pd/Ni systems were similar. The level of conjugated dienes decreased rapidly during hydrogenation with both Pd alone and with the Pd/Ni combination and no changes in conjugation were detected in the presence of the Ni catalyst alone. The increased activity of the Pd/Ni system over Pd alone was attributed to adsorption of catalyst poisons from the oil by Ni.     

Heat Transfer Analysis for Gas-to-Liquids Transportation Through Trans Alaska Pipeline

Gas-to-liquids (GTL) technology involves the conversion of natural gas to liquid hydrocarbons. In this article, theoretical studies have been presented to determine the feasibility of transporting GTL products through the Trans-Alaska Pipeline System (TAPS). To successfully transport GTL through TAPS, heat loss along the route must be carefully determined. This study presents heat transfer and fluid dynamic calculations to evaluate this feasibility. Because of heat loss, the fluid temperature decreases in the direction of flow and this affects the fluid properties, which in turn influence convection coefficient and pumping power requirements. The temperature and heat loss distribution along the pipeline at different locations have been calculated. Fairly good agreement with measured oil temperatures is observed. The powers required to pump crude oil and GTL individually, against various losses have been calculated. Two GTL transportation modes have been considered; one as a pure stream of GTL and the second as a commingled mixture with crude oil. These results show that the pumping power and heat loss for GTL are less than that of the crude oil for the same volumetric flow rate. Therefore, GTL can be transported through TAPS using existing equipment at pump stations.     

Portable Infrared Spectrometer to Characterize and Differentiate Between Organic and Conventional Bovine Butter

The performance of a portable infrared system combined with pattern recognition to discriminate between organically and conventionally produced bovine butter samples as well as to predict the levels of conjugated linoleic acid (CLA) were evaluated. Sixty butter (27 organic and 33 conventional) samples were used in this study. Bovine butter–fat were applied onto an attenuated total reflectance infrared (ATR‐IR) accessory equipped with a five‐bounce ZnSe crystal set at 65 °C for spectral collection. In addition, ATR‐IR spectra of bovine butter were directly collected at room temperature to avoid phase separation. The fatty acid profile and the levels of CLA were determined using reference FAME‐GC‐FID analysis. SIMCA models showed well separated clusters that discriminated between organic and conventional bovine butters due to C=C trans bending out of the plane vibration modes band at 967 cm^?1. Additionally, strong PLSR models were developed to predict CLA levels using butter–fat and bovine butter spectra with SEP of 0.05 % and RPD of 4.7, indicating that the models are suitable for quality control applications. Portable IR technology offers the ability for “in situ” analysis of butters that is much less time consuming than current analytical practices for authentication and quality control efforts by the industry.     

Trans10,cis15 18:2 Isolated from Beef Fat Does Not Have the Same Anti-Adipogenic Properties as Trans10,cis12–18:2 in 3T3-L1 Adipocytes

During ruminal biohydrogenation of α‐linolenic acid, a non‐conjugated non‐methylene interrupted dienoic acid is formed containing a t10 double bond, namely t10,c15–18:2. The present study was designed to examine whether t10,c15–18:2 would exert similar anti‐adipogenic effects compared to t10,c12–18:2 in 3T3‐L1 adipocytes. Differentiated 3T3‐L1 adipocytes were treated with 35 or 70 µM of LNA, t10,c12–18:2, t10,c15–18:2, or bovine serum albumin (BSA) vehicle control for 120 h. Cellular triacylglycerol and protein were quantified using commercial colorimetric kits. Cells were analyzed for fatty acid composition and gene expression using gas chromatography and quantitative PCR, respectively. Trans10,cis12–18:2 decreased (P < 0.05) the adipocyte triacylglycerol (TAG) content, which was mainly related to a reduction in saturated fatty acids (SFA; e.g., 16:0 and 15:0) and cis monounsaturated fatty acids (c‐MUFA; e.g., c9–16:1 and c9–18:1). Trans10,cis12 also decreased (P < 0.05) the expression of genes related to fatty acid synthesis (ACACA, FASN), delta‐9 desaturation (SCD1), fatty acid elongation (ELOVL5), and fatty acid uptake (LPL) and upregulated (P < 0.05) the expression of the rate‐liming enzyme involved in fatty acid β‐oxidation (CPT1). In contrast, LNA and t10,c15–18:2 did not affect the gene expression and cellular content of the TAG, SFA, c‐MUFA, or SCD1 indices in adipocytes. Our findings suggest that t10,c15–18:2, despite having structural similarity to t10,c12–18:2 (presence of a trans‐10 double bond), does not exert anti‐adipogenic effects in 3T3‐L1 adipocytes.     

trans Fatty Acids in Colostrum,Mature Milk and Diet of Lactating Adolescents

The purpose of this study was to investigate the trans fatty acids (TFA) content and distribution in colostrum, mature milk, and diet of adolescent mothers, after TFA declaration in food labels became mandatory in Brazil. Participants were healthy adolescents (n 54, 15–19 years, 1–90 days postpartum) practicing exclusive breastfeeding. Milk samples were collected 3 days after delivery (colostrum) and in the third month postpartum (mature milk) by hand expression. The fatty acid composition of the milk samples was determined by gas chromatography. TFA intake corresponded to 1.23 % of total energy value. Total 18:2 TFA accounted for less than 0.5 % of the energy intake. The amount of total 18:1 TFA (mean ± SEM) was 1.9 % ± 0.14 in colostrum and 1.5 % ± 0.2 in mature milk. The total content of n‐3 PUFA was inversely correlated with the total content of 18:1 TFA in colostrum. Both in colostrum and in mature milk, vaccenic acid (11t‐18:1) was found to be the most abundant 18:1 trans isomer, followed by elaidic acid (9t‐18:1), whereas rumenic acid (9c,11t‐18:2 CLA) was the predominant 18:2 trans isomer. In conclusion, the levels of TFA of industrial sources found in the mother's diet and breast milk (colostrum and mature milk) showed a decrease in relation to those observed in studies conducted prior to the TFA labeling resolution in Brazil. However, the current low intake levels of n‐3 LCPUFA and DHA content in the milk of lactating adolescents may be insufficient for supporting adequate neurological development of the infants.     

Comparison of Soybean and Cottonseed Oils upon Hydrogenation with Nickel,Palladium and Platinum Catalysts

There is current interest in reducing the trans fatty acids (TFA) in hydrogenated vegetable oils because consumption of foods high in TFA has been linked to increased serum cholesterol content. In the interest of understanding the TFA levels, hydrogenation was carried out in this work on soybean oil and cottonseed oil at two pressures (2 and 5 bar) and 100 °C using commercially available Ni, Pd, and Pt catalysts. The TFA levels and the fatty acid profiles were analyzed by gas chromatography. The iodine value of interest is ~70 for all-purpose shortening and 95–110 for pourable oil applications. In all cases, higher hydrogen pressures produced lower levels of TFA. In the range of 70–95 iodine values for the hydrogenated products, the Pt catalyst gave the least TFA, followed closely by Ni, and then Pd, for both oils. For all three catalysts at 2- and 5-bar pressures and 70–95 iodine values, cottonseed oil contained noticeably less TFA than soybean oil; this is probably because cottonseed oil contains a lower total amount of olefin-containing fatty acids relative to soybean oil. Approximate kinetic modeling was also done on the hydrogenation data that provided additional confirmation of data consistency.     

电力变压器的动稳定

在变压器短路电动力的计算中,目前是以静态力代替动态力的方法来进行的。这不能适应变压器机械强度的要求。针对此问题,从电动力的基本理论出发,建立起变压器的动态数学模型,对变压器在短路电流作用下线圈产生的动态力进行了理论分析和计算,对在短路电流作用下的变压器线圈(器身)绝缘结构进行了初步研究,提出了动稳定的计算方法。     

Colour research with architectural relevance: How can different approaches gain from each other?

Colour research from different scientific traditions start from different basic questions and use different methods and concepts. This makes it difficult to communicate and to judge result relevance in a wider perspective. Here we start from architects' need of colour knowledge and discuss recent studies of colour appearance and colour emotion, with and without explicit connection to architecture. We stress the need for further development and clarification of concepts and conclude that the multitude of studies with different approaches can be seen as cases, jointly adding to a widened and deepened understanding of colour. © 2010 Wiley Periodicals, Inc. Col Res Appl, 2010     

Individual trans 18:1 Isomers are Metabolised Differently and Have Distinct Effects on Lipogenesis in 3T3‐L1 Adipocytes

The objective of this research was to study the metabolism of individual trans fatty acids (FAs) that can be found in ruminant fat or partially hydrogenated vegetable oils (PHVO) and determine their effects on FA composition and lipogenic gene expression in adipocytes. Differentiated 3T3‐L1 adipocytes were treated with 200 µM of either trans‐9‐18:1, trans‐11‐18:1, trans‐13‐18:1, cis‐9‐18:1 or BSA vehicle control for 120 h. Trans‐9‐18:1 increased total cell FA content (µmole/well) compared to other FA treatments, which was mainly related to the accumulation of trans‐9‐18:1 in the cells. Adipocytes were able to desaturate a significant proportion of absorbed trans‐11‐18:1 and trans‐13‐18:1 (~20 and 30 % respectively) to cis‐9,trans‐11‐18:2 and cis‐9,trans‐13‐18:2, whereas trans‐9‐18:1 was mostly incorporated intact resulting in a greater lipophilic index (i.e. decreased mean FA fluidity) of adipocytes. Trans‐9‐18:1 up‐regulated (P < 0.05) the expression of lipogenic genes including acetyl‐CoA carboxylase (1.65 fold), FA synthase (1.45 fold), FA elongase‐5 (1.52 fold) and stearoyl‐CoA desaturase‐1 (1.49 fold), compared to the control, whereas trans‐11‐18:1 and trans‐13‐18:1 did not affect the expression of these genes compared to control. Our results suggest that the metabolism and lipogenic properties of trans‐11‐18:1 and trans‐13‐18:1, typically the most abundant trans FA in beef from cattle fed forage‐based diets, are similar and are different from those of trans‐9‐18:1, the predominant trans FA in PHVO.