The influence of certain factors on thickness loss after the hot gluing of cut lamellas into solid wood layered boards

An experimental laboratory investigation has been carried out into the hot gluing of solid wood layered boards made out of 5.3 mm thick solid-wood lamellas, the latter being produced by the lengthwise veneer cutting technique, the object of the research being to determine some of the reasons (humidity of wood before heating, temperature of wood before cutting into lamellas, and temperature and pressure during the gluing of boards) for the permanent thickness loss which occurs during gluing. Spruce wood (Picea abies (L.) Karst.) was used in the experimental tests. Before cutting into lamellas, this wood was classified into two humidity groups, and heated to three different temperatures. The dried lamellas were used, after suitable preparation, for the two outer layers, which were glued, together with a middle layer of sawn lamellas, by the hot gluing process. A total of 162 laboratory boards, of length 500 mm, width 475 mm and thickness from 24 to 25 mm, were hot glued, using melamin-urea-formaldehyde glue, at three different gluing temperatures and three different gluing pressures. Regression analysis of the measured results of thickness loss showed that the influence of the studied factors on thickness loss was linear, and that thickness loss depends the most on gluing pressure, followed by gluing temperature. It was also found that a higher wood humidity results in a slightly greater thickness loss than the wood’s temperature before cutting into lamellas.     

The influence of certain metal ions on the visible spectra of food dyes

Summary. The visible absorption spectra of twenty-two food dyes have been plotted both in the free state and in the presence of added calcium, magnesium, aluminium, iron (II), iron (III), copper (II) and cobalt (II) ions at the pH values 3.0, 6.4, 7.4 and 12.5.
The frequencies of the absorption band maxima of the free dyes are briefly discussed in relation to colour and structure. While added metal ions do not, in general, have an appreciable effect on the spectrum of the dye, the transition metal ions studied frequently bring about a shift in the characteristic frequencies of the free-dye absorption maxima. Examples of where this effect is greatest are carmoisine in the presence of copper (II) at pH 6.4 and 7.4, and black PN in the presence of iron (II) at pH 12.5.
The possibility of dye complexes affecting iron metabolism is also briefly discussed.     

The influence of technical factors on differential cell count in milk

Differential cell count of milk is a traditional parameter for the evaluation of udder health. The literature shows great variation in differential cell counts of the milk of healthy mammary glands: macrophages range from 0% to 80%, lymphocytes from 1.5% to 79.5%, polymorphonuclear neutrophils from 3% to 95%, and epithelial cells from 1% to 19%. We conducted three studies to seek explanations for such variation. In the first, we evaluated the impact of polyethylene and glass sampling bottles. The aim of the second study was to compare the results of differential cell counts performed by three different technicians. The third study evaluated two methods of smear preparation. When polyethylene plastic bottles were used, the macrophage population was minimized but lymphocytes remained unaffected. This was shown by an exemplary flow cytometric analysis using four monoclonal antibodies against three lymphocyte surface structures. There were significant differences in the differential cell counts of 40 smears made by three technicians despite identical operating procedures. For the sediment smear, milk was centrifuged once and the sediment spread by eye on a glass slide. For the "coffee grinder" smear method, the sample was subjected to four centrifugations and then placed on a cover glass in order to spread the sediment using centrifugal force. The coffee grinder procedure led to a reduction of lymphocytes and an enrichment of polymorphonuclear neutrophils without affecting the macrophage population. Both methods made it possible to distinguish different udder health classes. It can be concluded that differential cell counts are a useful tool for comparing and monitoring udder health only if: samples are taken in a glass bottle; smears are prepared with the identical technique; and the differential cell counts are performed by a single person.     

烤烟烟叶DNA甲基化与气象因子的关系分析

为深入研究特色烟叶的形成与气象因子的关系,用灰色关联理论结合生产实际选出与烟叶DNA甲基化相关的平均最高温度、总日照时数、平均相对湿度和总降雨量等4个气象因子,并建立了DNA甲基化(因变量)与4个气象因子(自变量)之间修正的Logistic模型.单因子效应分析表明,平均最高温度、总日照时数和平均相对湿度与DNA甲基化水...     

尾叶桉制浆的生产实践

介绍了尾叶桉的纤维特征、化学组成,制浆工艺流程、设备选型、技术参数以及生产过程中遇到的问题与解决办法,并与马尾松浆进行了比较.     

影响低温火腿肉色泽的因素研究

色泽是衡量低温火腿肉品质的重要感官指标。通过试验研究确定确定影响低温火腿肉色泽的主要因素是肉的比例结构、杀菌温度、亚硝酸钠加入量、乙基麦芽酚是否加入及其加入量，其中一个因素发生变化，肉的色泽没有相应的改变。     

蒸煮助剂DA2709用于进口桉木的蒸煮实践

通过工艺优化、设备改造、使用蒸煮助剂,漂白浆产量由22万t/a提高到29.5万t/a,蒸煮用碱量降低5.0%,未漂浆得率提高3.3%,漂后浆得率提高2.9%,TDS降低5.40%,在蒸煮卡伯值提高7.7%的情况下,氧脱后卡伯值、白度仍维持在目标范围内,ClO2消耗平均降低10.8%,Cl2消耗平均降低8.3%,总渣子量降低5.3%.     

影响低温火腿肉嫩度因素的研究

嫩度是衡量低温火腿肉品质的重要感官指标。通过试验研究确定影响低温火腿肉嫩度的主要因素是肉的选择及其比例结构、杀菌温度、是否加入磷酸盐、氯化钙、淀粉等,其中一个因素发生变化,肉的嫩度有相应的改变。     

温度对聚酯增强基PVC篷盖布蠕变应变性能的影响

分析了不同测试温度条件下,3种聚酯增强基PVC篷盖布试样加载24 h内的蠕变应变特性.结果表明,各试样经纬向的蠕变应变曲线基本相同,试样蠕变应变的大小受测试温度、加载时间和聚酯增强基布中衬经衬纬纱排列密度的影响.测试温度越高,试样的蠕变应变越大.同规格试样纬向的蠕变应变大于其经向.聚酯增强基PVC篷盖布试样经纬向的蠕变应变随增强基布中衬经衬纬纱排列密度的增加而增大.     

The influence of cow factors on the incidence of clinical mastitis in dairy cows

Many cow-specific risk factors for clinical mastitis (CM) are known. Other studies have analyzed these risk factors separately or only analyzed a limited number of risk factors simultaneously. The goal of this study was to determine the influence of cow factors on the incidence rate of CM (IRCM) with all cow factors in one multivariate model. Also, using a similar approach, the probability of whether a CM case is caused by gram-positive or gram-negative pathogens was calculated. Data were used from 274 Dutch dairy herds that recorded CM over an 18-mo period. The final dataset contained information on 28,137 lactations of 22,860 cows of different parities. In total 5,363 CM cases were recorded, but only 2,525 CM cases could be classified as gram-positive or gram-negative. The cow factors parity, lactation stage, season of the year, information on SCC from monthly test-day records, and CM history were included in the logistic regression analysis. Separate analyses were performed for heifers and multiparous cows in both the first month of lactation and from the second month of lactation onward. For investigating whether CM was caused by gram-positive or gram-negative pathogens, quarter position was included in the logistic regression analysis as well. The IRCM differed considerably among cows, ranging between 0.0002 and 0.0074 per cow-day at risk for specific cows depending on cow factors. In particular, previous CM cases, SCC in the previous month, and mean SCC in the previous lactation increased the IRCM in the current month of lactation. Results indicate that it is difficult to distinguish between gram-positive and gram-negative CM cases based on cow factors alone.     

利用正交实验和模糊评价改进香榧加工工艺

为提高香榧加工品品质,改进香榧加工工艺,以香榧为原料,在单因素试验基础上,通过对香榧加工工艺进行3因素3水平的正交实验设计(第1次炒制时间、浸泡液浓度、第二次炒制时间),并应用模糊评价法对香榧加工品进行感官评定,以模糊评定结果作为正交实验结果值,通过正交设计助手ⅡV3.1进行结果分析。研究结果表明,椒盐香榧加工工艺最佳工艺是:第1次炒制10 min,0.02%V E+2%盐水浸泡液,第2次炒制10 min,在此工艺条件下制得香榧的感官评定结果达到79.9分,验证实验结果证明,该方法用于优化香榧的加工工艺切实可行,为进一步提高香榧品品质提供了理论依据。     

影响甘蓝泡菜中亚硝酸盐含量因素的研究

摘要：本文以甘蓝为主要原料，研究了在30℃条件下影响甘蓝泡菜中亚硝酸盐含量的几种主要因素．结果表明：采用纯接种技术，在发酵前期可有效降低亚硝酸盐的含量，其中以接种肠膜明串珠菌效果最佳；同时在发酵过程中添加适量蒜汁或姜汁，可明显地抑制甘蓝乳酸发酵中亚硝峰出现；且在发酵过程中，泡菜的pH值对亚硝酸盐含量也有较大的影响。在发酵成熟后，泡菜中的亚硝酸盐含量趋于稳定，且各种发酵方式对成熟泡菜中亚硝酸盐的含量基本无影响。     

双乙酰测定影响因素的研究

双乙酰是啤酒中重要的风味物质,它的含量是啤酒质量的一个重要指标。通过对不同样品,在不同的比色时间、不同的样品温度及新鲜程度条件下测定其吸光度,得出不同实验条件对测定结果的影响,以求在实验中掌握好其关键点,确保测定结果的准确性。     

桉木APMP制浆工艺及其优化

研究了按木APMP的木片挤碾、螯合前处理和化学预处理等最佳制浆工艺，并在此基础上探讨了按木APMP与蔗渣化机浆配抄胶印书刊纸的可能性。使用挤碾机处理桉木木片，以利于药液浸透，较大幅度地提高纸页的白度和强度，是本研究的创新之处。     

分析影响大米水分因素

大米水分是大米一个重要质量指标。该文从原粮供应至终端销售整个生产体系对大米水分有影响因素进行综合分析,以便生产企业参考。     

The influence of extrinsic factors on the microbiological spoilage pattern of ground beef

Two hundred and thirty four samples of raw minced beef were subjected to storage at 0 and 7 degrees C over a period of 17 days. The samples were subjected to four different treatments where the controls (Treat 1) were aerobically packed. The vacuum-packed samples (Treats 2 and 3) differed only by the addition of 0.5% L-(+)-ascorbic acid to the Treat 3 samples. Treat 4 represented aerobically packed samples to which a commercial 'colour retainer' was added. The microbiological results showed clearly that temperature control around 0 degree C was the central element in achieving shelf life extension of raw minced beef. Vacuum packaging and additive treatments enhanced the effect of low storage temperatures. Identification of 128 psychrotrophic spoilage isolates revealed a predominance of Gram-negative bacteria (63%), most of which were classified as Pseudomonas spp. (72%), the rest being Enterobacteriaceae. Among Gram-positive isolates, lactobacilli and yeasts predominated (45% and 28%, respectively). Commonly observed oxygen relationships were not found in this study. Pseudomonads proliferated even in vacuum packaged samples throughout the entire storage period, whilst lactic acid bacteria were also found in high numbers in aerobically packaged samples. Identification of 71 isolates of lactic acid bacteria revealed a strong predominance of Lactobacillus saké (34%), followed by L. curvatus (23%), L. bavaricus (21%) and L. alimentarius (10%). Significant numbers of lactobacilli were isolated from samples in all treatment groups, including the aerobically packed categories.     

调控Streptomyces sp菌株生长、代谢提高纳他霉素产量的研究

本文研究了不同碳源、氮源、培养基起始pH和D.O值等对Streptomyces sp菌株生长、代谢提高纳他霉素(Natamycin)产量的影响,用正交试验确定了该菌株的最佳培养基配方为:2%的葡萄糖,3%的玉米淀粉,2%的大豆蛋白胨,0.5%的酵母粉,并确定了该菌株产纳他霉素的最佳pH、D.O值以及糖、氮比例,在50升发酵罐中纳他霉素产量高达6.6g/L。     

塑身内衣压力舒适性的影响因素分析

分析了影响塑身内衣舒适性的因素,包括面料性能、服装款式、服装质量、宽裕量、人体活动水平、人体体型特征等,为合理设计塑身内衣提供参考。     

上市银行审计收费影响因素的研究

运用最小二乘法,分析了我国上市商业银行2007～2009年所支付的审计费用的影响因素.通过SPSS17.0统计分析软件对搜集到的相关数据进行多元线性回归分析.发现上市商业银行的股权集中度、不良贷款率和事务所规模与审计收费存在显著相关性,并在此基础上为上市银行提出了相应的建议和对策.     

环境因子对Maillard反应形成肉香味的影响

文章浅述了肉香味,重点研究肉的化学组成、体系的水分含量、pH、反应温度/时间以及缓冲体系等环境因子对Maillard反应形成肉香味的影响.同时,就目前该领域的发展方向提出了一些建议,以期为天然肉味香精的生产控制提供理论依据.