410t/h劣质烟煤锅炉掺烧褐煤改造技术研究

二道江发电公司煤源严重不足,为最大限度掺烧褐煤并能单烧当地劣质烟煤,在2×100MW机组锅炉进行技术改造。采用抽取中温炉烟加入制粉系统干燥介质,同时对热风送粉系统加入调温风的改造方案,以降低制粉系统末端氧量以及送粉系统输送介质的温度,提高制粉、送粉系统防爆能力和制粉系统的干燥能力以及双通道燃烧器对有较大差异煤种的适应能力。运行表明,改造效果显著,锅炉具备掺烧褐煤50%的能力。     

优良己酸菌分离培养及冷干保藏条件研究

以大曲酒窖窖泥为材料,对己酸菌进行了分离纯化,并对己酸菌菌种的真空冷冻干燥保藏方法进行了研究,初步确定了菌种冻干保藏的预冻温度及保护剂浓度。比较了己酸菌不同保存方式的保藏效果,实验表明采用冷冻干燥保藏法长期保藏菌种效果良好。     

不同处理方式下膨化玉米粉的冲调性能分析

该研究以膨化玉米粉为原料,分析磷酸化、酶处理、食用胶干热和复合处理对膨化粉吸水性指数、水溶性指数、分散时间、结块率、黏度、粒径和色度的影响。结果表明,磷酸化热处理对膨化粉黏度无显著影响;食用胶干热处理黏度增加;酶处理及其与磷酸化、食用胶干热复合处理吸水性指数和黏度显著降低,水溶性指数大于磷酸化和食用胶干热处理。α-淀粉酶处理粉的水溶性指数从30.4%增至80.98%,吸水性指数从4.96降至1.21。黄原胶α-淀粉酶、α-淀粉酶正磷酸钠复合处理膨化粉结块率分别为1.63%、1.46%,低于正磷酸钠、α-淀粉酶、中性蛋白酶、黄原胶干热处理粉结块率,分别为5.57%、5.60%、6.16%、5.58%,两种复合处理方式下黏度较稀,分别为83.33 mPa·s、100 mPa·s;正磷酸钠、黄原胶干热处理黏度分别为2243.33 mPa·s、306.33 mPa·s,正磷酸钠联合中性蛋白酶处理黏度、结块率分别为546.67 mPa·s、4.89%,黏度适中,结块率低于单一处理,此时分散时间、粒径分别为4.81 s、131.14μm,呈淡黄色。综合分析,正磷酸钠中性蛋白酶复合处理下膨化米粉冲调...     

油脂改性技术开发动向(Ⅰ)

目前,人们日益关注有关反式脂肪酸及环境安全等问题,同时,随着棕榈油生产量扩大,对油脂改性技术研究开发动向所带来影响也给予极大重视。该文着重以油脂加工中新开发降低反式脂肪酸氢化技术,干式分提技术,酶法酯交换技术为中心最近开发动向作一解说。     

Effect of varying levels of fatty acids from palm oil on feed intake and milk production in Holstein cows

To determine the optimum feeding level of fatty acids of palm oil (PALM; Energizer RP10; 86.6% palmitic acid) on milk production, lactating cows (n = 18) were randomly assigned to a treatment sequence in replicated 4 × 4 Latin squares. Animals were assigned to squares by parity (3 multiparous and 1 primiparous squares with primiparous in the incomplete square). The 4 diets were designed to provide 0, 500, 1,000, and 1,500 g of PALM per day. Cows were fed individually with feed intake measured daily. Each period lasted 16 d with milk production and composition determined the final 2 d. Milk production, milk composition and feed intake data were analyzed using the MIXED procedure of SAS. Milk yields were 30.9, 34.0, 34.2, and 34.2 kg/ d (SEM = 1.9) for the 0, 500, 1,000, and 1,500 g levels, respectively. Milk yield was increased by the addition of PALM; however, there were no differences among the levels of PALM. Milk fat percentage was also increased from 3.44% for 0 g to 3.95% (SEM = 0.17) across all levels of PALM but there were no differences among the PALM treatments. Dry matter intakes were 23.3, 26.4, 24.7, and 23.8 kg/d (SEM = 1.4) for the 0, 500, 1,000 and 1,500 g levels, respectively. The addition of PALM increased milk yield and milk fat percentage, and no adverse effects on dry matter intake were observed.     

Herd management factors that affect duration and variation of adherence of an external teat sealant

During 1998 and 1999, a purposive sample of Ontario dairy herds was enrolled in a study to examine management factors associated with adherence of an external teat sealant. A total of 74 herds were recruited that had previously complied with a provincial Sentinel Herd mastitis study. All herds were sent a management survey and a commercially available external teat sealant product. The sealant was applied to all cows in first lactation or greater that were scheduled to go dry. Adherence of the teat sealant was scored on a scale of 1 to 5 (1 = sealant completely removed) for the first 12 d following dry off. Complete data were analyzed from 806 cows in 48 herds (mean of 17 cows/herd). Mean duration of adherence of the teat sealant was 4 d (range 1 to 7 d). Of the management factors recorded, only changing the feed to reduce milk production prior to drying off was significantly associated with 0.78-d prolonged adherence. No factors related to dry cow housing, bedding material, or floor surface were associated with the duration of adherence. The variance around the duration of adherence was examined. The median variance of adherence was 3.0 d², which was equivalent to a standard deviation of 2.6 d. Herds in which dry cows were housed in tie-stall barns, and the herds that used a penicillin and novobiocin combination dry cow antibiotic had the greatest variation. We concluded that modifying the ration to reduce milk production enhanced adherence of an external teat sealant. Teat-end preparation prior to application of the teat sealant is an important factor to consider when choosing to adopt this dry period mastitis prevention strategy. This study demonstrates that beyond cow- and quarter-level factors, herd management factors can influence the duration and variation of sealant adherence experienced among different herds.     

环保型羊毛织物干洗剂的应用研究

对石油干洗剂SD60添加表面活性剂,提高其增溶作用,使干洗剂对羊毛织物有了更好的干洗效果,可代替毒性较强的四氯乙烯干洗剂。     

A new oxygen barrier film reduces aerobic deterioration in farm-scale corn silage

Recently, many studies have focused on the aerobic deterioration of corn silage at the farm level, because a large part of the product stored in horizontal silos is exposed to air and is more prone to spoilage. The most important factor influencing the preservation of forage ensiling is the degree of anaerobiosis that is usually achieved with sheets of polyethylene. A new black-on-white (125-μm) coextruded oxygen barrier (OB) film has been developed for silage sealing and was tested in the present experiment to assess the effects on fermentation quality, dry matter losses, and yeast and mold counts at opening of whole-crop corn bunker silos compared with conventional polyethylene (ST) film. Two trials were carried out on 2 commercial farms. The bunkers were divided into 2 parts along the length so that half of the feedout face would be covered with ST film and the other half with OB film. Eight plastic net bags with well-mixed fresh material were weighed and buried in the upper layer of the bunker, and 4 bags were buried in the central part. The silos were opened for summer consumption and were fed out at different rates (19 vs. 33 cm/d). The bags were unloaded, weighed, and subsampled to analyze the DM content, pH, lactic and monocar-boxylic acids, ammonia, yeast and mold counts, and aerobic stability. The pH of the peripheral silage was different under the 2 films, with a lower value in the OB treatment. The OB film on farm 1 affected the silage dry matter losses, which were reduced 3.7 times in comparison with the ST film sealing. On farm 2, although the dry matter losses were numerically higher in the silage sealed with the ST film compared with OB film (9.0 vs. 5.9%, respectively), the difference was not statistically significant. However, the corn silage sealed with the ST film was less stable than the silage sealed with the OB film. The results indicate that the new OB film is a promising tool to constrain spoilage and dry matter losses under critical farm conditions, when inadequate amounts of silage are removed daily. The OB film further improved the stability of the corn silage in the peripheral areas of the silos even when a proper harvest-to-feedout management was implemented.     

Genetics of grass dry matter intake, energy balance, and digestibility in grazing irish dairy cows

The objective of this study was to estimate genetic parameters for grass dry matter intake (DMI), energy balance (EB), and cow internal digestibility (IDG) in grazing Holstein-Friesian dairy cows. Grass DMI was estimated up to 4 times per lactation on 1,588 lactations from 755 cows on 2 research farms in southern Ireland. Simultaneously measured milk production and BW records were used to calculate EB. Cow IDG, measured as the ratio of feed and fecal concentrations of the natural odd carbon-chain n-alkane pentatriacontane, was available on 583 lactations from 238 cows. Random regression and multitrait animal models were used to estimate residual, additive genetic and permanent environmental (co)variances across lactations. Results were similar for both models. Heritability for DMI, EB, and IDG across lactation varied from 0.10 [8 days in milk (DIM)] to 0.30 (169 DIM), from 0.06 (29 DIM) to 0.29 (305 DIM), and from 0.08 (50 DIM) to 0.45 (305 DIM), respectively, when estimated using the random regression model. Genetic correlations within each trait tended to decrease as the interval between periods compared increased for DMI and EB, whereas the correlations with IDG in early lactation were weakest when measured midlactation. The lowest correlation between any 2 periods was 0.10, −0.36, and −0.04 for DMI, EB, and IDG, respectively, suggesting the effect of different genes at different stages of lactations. Eigenvalues and associated eigenfunctions of the additive genetic covariance matrix revealed considerable genetic variation among animals in the shape of the lactation profiles for DMI, EB, and IDG. Genetic parameters presented are the first estimates from dairy cows fed predominantly grazed grass and imply that genetic improvement in DMI, EB, and IDG in Holstein-Friesian cows fed predominantly grazed grass is possible.     

Quality of plant products from organic agriculture

During the last decade, consumers' trust in food quality has decreased drastically, mainly because of growing ecological awareness and several food scandals (e.g. BSE, dioxins, bacterial contamination). It has been found that intensive conventional agriculture can introduce contaminants into the food chain. Consumers have started to look for safer and better controlled foods produced in more environmentally friendly, authentic and local systems. Organically produced foods are widely believed to satisfy the above demands, leading to lower environmental impacts and higher nutritive values. So far, studies have partly confirmed this opinion. Organic crops contain fewer nitrates, nitrites and pesticide residues but, as a rule, more dry matter, vitamin C, phenolic compounds, essential amino acids and total sugars than conventional crops. Organic crops also contain statistically more mineral compounds and usually have better sensory and long‐term storage qualities. However, there are also some negatives: plants cultivated in organic systems generally have 20% lower yields than conventionally produced crops. Several important problems need to be addressed in the coming years: environmental, bacterial and fungal contamination of organic crops and, the most essential issue, the impact of organic food consumption on animal and human health. Copyright © 2007 Society of Chemical Industry