Pressure relief-dipping-microwave assisted polymerization of melamine-L-aspartic acid resin at activated carbon for purification of L-threonine fermented crude product

L-threonine(L-Thr) obtained by fermentation often contains vestigial hydrosoluble Pb(Ⅱ), Fe(Ⅱ), L-glutamic acid(L-Glu) etc., which affect the product quality. Poly melamine and L-aspartic acid(L-Asp) resin functional coconut shell activated carbon composite(PMA/AC) was prepared by a pressure relief-dipping-microwave assisted polymerization method for the simultaneous removals. The adsorption capacities of Pb(Ⅱ), Fe(Ⅱ) and L-Glu could reach to 82.34 mg·g^(-1), 57.82 mg·g^(-1) and 102.58 mg·g^(-1) at conditions of pH 5.0, 45 °C and 4 h with an initial concentration of 0.01 mol·L^(-1), respectively. The present PMA/AC was successfully used to the simultaneous removals of vestigial Pb(Ⅱ), Fe(Ⅱ) and L-Glu from the fermented crude product solution of L-Thr. Moreover, the PMA/AC was carefully characterized by FE-SEM, IR et al. analysis techniques, the results show that abundant PMA particles evenly distributed at the inner and outside surface of AC with a size of(50 ± 20) nm.

A Markov-switching dynamic regression analysis of the asymmetries related to the determinants of US crude oil production between 1982 and 2019

The structural changes brought about by shale oil revolution have inspired this paper of which the aim is to analyze the potential asymmetries related to the determinants of crude oil production in the USA.Thus,using a Markov-switching dynamic regression model in which parameters change when oil production moves from one regime to the other,it is found that for both oil production and oil relative importance,the regime that was dominant during the 1980s and the early 1990s when oil production in the USA was substantially high is the same regime that has once again become dominant in the decade corresponding to the shale oil revolution.Furthermore,the study reveals the existence of asymmetries in the relationship between US crude oil production and both manufacturing production and the consumer price index.Asymmetries are also found in the relationship between the relative importance US crude oil and manufacturing production.Finally,it is found that the intercept and the variance parameter also vary from one regime to the other,thus justifying the use of regime-dependent models.

Effects of Crude Fiber Levels on Production Performance, Organ Index and Serum Biochemical Parameters of Dingan Geese Aged from 1 to 28 Days

[Objective]The paper was to investigate the effects of dietary crude fiber level on production performance,organ index and serum biochemical parameters of Dingan geese aged from 1 to 28 days.[Method]A total of 144 1-day-old Dingan geese with the same genetic background and similar initial weight(88.75±0.21g)were randomly assigned into 3 groups with 4 replicates per group and 12 geese per replicate,and fed with the diets containing 2.56%,3.52% and 4.48% crude fiber,respectively.The trial lasted 28 d.[Result]1)The final weight and daily gain of 3.52% CF group were significantly higher than those of 2.56% CF group(P<0.05);the feed/gain ratio was markedly lower than that of 2.56% CF group(P<0.05).2)The slaughter rate,semi-eviscerated rate and leg muscle rate of 3.52% CF group were higher than those of 2.56% and 4.48% CF groups(P>0.05).3)As the dietary crude fiber levels rose,the abdominal fat rate showed a downward trend(P>0.05).4)The liver index of 3.52% CF group was significantly higher than that of 2.56% CF group(P<0.05).4)Compared with 2.5%and 4.48% CF groups,the serum albumin concentrations of 3.52% CF group markedly increased(P<0.05),the serum total protein and globin contents were higher(P>0.05),but the serum uric acid level was lower(P>0.05).[Conclusion]When the crude fiber level was 3.52%,the production performances of Dingan geese aged from 1 to 28 days were better,and the liver index and serum albumin level could be obviously improved.

Production of Ca₂AlNbO₆Ceramics and Study of Their Stability in Crude Petroleum for the Conservation of Metallic Sensing Elements used in Petroleum Extraction

In the present work a niobium based complex cubic perovskite oxide Ca2AlNbO6 ceramic was produced, characterized and studied its stability in crude petroleum environment for inert ceramic embedding for temperature sensors used in petroleum extraction. Ca2AlNbO6 ceramic powder was prepared through thermo-mechanical processing. Structural characteristics of calcined material was investigated by powder X-ray diffarctometry, which presented a single phase complex cubic perovskite structure with lattice parameter a = 7.6599 ?. Compacted discs of Ca2AlNbO6 ceramics were sintered in the temperature range 1250°C - 1350°C during 24 hours in ambient atmosphere. Microstructure of the sintered ceramics was studied by scanning electron microscopy and mechanical behavior was studied by Vicker’s microhardness testing. Ca2AlNbO6 ceramics sintered at 1350°C presented best results in terms of microstructural homogeneity and mechanical hardness. Therefore these sintered ceramics were submerged in crude petroleum for 60 days. Ceramics were taken out from the petroleum periodically and subjected to structural, microstructural and mechanical characterizations. Results showed that ceramics submerged in crude petroleum did not suffer any change at any stage of submersion. These characteristics make this material suitable for inert ceramic embedding for sensors used in petroleum extraction.

新疆畜禽饲料资源中粗蛋白含量的调查研究

试验旨在研究新疆不同地州间各种常规饲料原料的粗蛋白含量和分布情况,为各地州饲粮合理配制提供科学依据。对新疆全区14个地州的13种115个主要畜禽饲料原料在科学采样的基础上进行粗蛋白含量测定。对同类不同种饲料样品和不同饲料样品的粗蛋白含量进行单因素方差分析,比较不同饲料原料中粗蛋白含量的差异及不同地区之间的差异。结果表明:不同原料除青贮玉米外,干物质含量都在92%以上;粮油加工副产物的粗蛋白含量最高,粮食作物秸秆粗蛋白含量最低。8个地州采集玉米样品中喀什的粗蛋白含量最高。全疆各地州的各种类饲料原料中粗蛋白含量相互之间变化非常大,因此,实际应用中要充分考虑到不同区域饲粮中粗蛋白含量,为精准配方、精准营养提供技术支撑。

不同粗蛋白质水平对白王种鸽繁殖性能和乳鸽生长性能的影响

试验旨在探究“2+2”生产模式下不同粗蛋白质水平对白王种鸽繁殖性能和乳鸽生长性能的影响。试验选取产蛋性能相近的300日龄健康种鸽168对,随机分为4组,每组7个重复,每个重复6对种鸽,每对种鸽哺育2只乳鸽。试验Ⅰ组、Ⅱ组、Ⅲ组和Ⅳ组分别饲喂粗蛋白质水平为13.43%、15.04%、16.64%和18.25%的饲粮。试验期46 d,其中孵化期18 d (1~18 d),哺乳期28 d (19~46 d)。结果显示,试验Ⅱ组、Ⅲ组产蛋间隔显著低于试验Ⅰ组(P<0.05),试验Ⅲ组种蛋受精率显著高于试验Ⅰ组、Ⅳ组(P<0.05),试验Ⅲ组入孵蛋孵化率极显著高于试验Ⅰ组、Ⅱ组、Ⅳ组(P<0.01)。试验Ⅲ组乳鸽28日龄体重显著高于试验Ⅰ组(P<0.05),乳鸽屠宰率极显著高于试验Ⅰ组(P<0.01),乳鸽胸肌率显著高于试验Ⅰ组、Ⅱ组、Ⅳ组(P<0.05)。试验Ⅱ组、Ⅲ组、Ⅳ组窝料重比1极显著低于试验Ⅰ组(P<0.01)。研究表明,不同粗蛋白质水平影响了种鸽的繁殖性能、乳鸽的生长性能以及窝料重比,在“2+2”生产模式下,建议白王种鸽饲粮适宜粗蛋白质水平为16.64%。

基于六西格玛方法的A集输站外输流程优化

随着油田行业在环保和双控问题上的关注,企业越来越重视优化生产流程和提高产品质量。本文针对A集输站原油外输过程中存在的调参操作时间长、蒸汽成本高等问题,基于六西格玛方法对工艺流程进行了优化改进。通过DMAIC五个阶段,成功将人工调参时间从10分钟缩短至10秒钟,同时将蒸汽用量从每天36吨降低至23吨。这些改进显著降低蒸汽成本,有效优化站内原油外输流程。因此,本研究对提高A集输站的生产效率和成本控制具有重要意义。

饲粮粗蛋白质水平对太行鸡种鸡生产性能、蛋品质和营养物质表观利用率的影响

试验旨在探究饲粮不同粗蛋白质(Crude protein,CP)水平对产蛋期太行鸡种鸡生产性能、蛋品质和营养物质表观利用率的影响。试验选取健康且产蛋率相近的37周龄太行鸡种鸡288只,随机分为4组,每组6个重复,每个重复12只鸡。各组饲粮CP水平分别为15.50%、16.00%、16.50%和17.00%。正式试验期为42 d。结果显示:①16.50%CP组产蛋率显著高于16.00%、17.00%CP组(P<0.05);16.50%CP组料蛋比极显著低于15.50%、16.00%和17.00%CP组(P<0.01),且饲粮粗蛋白质水平与料蛋比呈二次曲线关系(P=0.015)。②随着饲粮粗蛋白质水平的提高,蛋壳厚度线性升高(P<0.05),其中17.00%CP组蛋壳厚度显著高于15.50%CP组(P<0.05)。③不同粗蛋白质水平显著影响粗蛋白质和有机物表观利用率(P<0.05),16.50%CP组太行鸡粗蛋白质表观利用率显著高于其他组(P<0.05);16.50%CP组有机物表观利用率最高(P<0.01),其次依次为16.00%CP组、15.50%CP组和17.00%CP组(P<0.01),且随着饲粮粗蛋白质水平的提高,粗蛋白质和有机物表观利用率呈二次曲线关系(P<0.05)。综合料蛋比、粗蛋白质和有机物表观利用率指标,产蛋期太行鸡饲粮适宜粗蛋白质水平为16.20%~16.40%。