初始pH值和物料配比对高温混料厌氧发酵进程的影响

为了研究高温条件下初始p H对厌氧发酵进程的影响,以猪粪、玉米秸秆为发酵原料,设置3种比例(干物质质量比30∶70、50∶50、70∶30)下6个水平(6.0、6.5、7.0、7.5、8.0的初始p H值以及一个不调控初始p H的处理作为对照)进行批次发酵试验.结果表明,初始p H值和物料配比都会显著影响厌氧发酵过程的启动时间和甲烷产量.当初始p H值为7.0时,VS降解率趋于稳定.COD去除率随着粪便含量的增加而逐渐降低.高温猪粪玉米秸秆混合发酵最佳挥发性脂肪酸(VFA)/碱度比值范围为0.05~0.3;猪粪可以作为一种缓冲材料,适量添加可增大消化系统的缓冲能力.通过建模优化,预测出当初始p H值为6.95、猪粪/玉米秆为70∶30时,可得到每克挥发性固体最大理论单位甲烷产量169.22 m L·g-1.     

台风“麦德姆”福州降水δ18O特征及水汽来源分析

大气降水的氢氧同位素不仅在长时间尺度和短时间尺度上对气候环境有一定的响应,而且在极端天气事件中也响应强烈。论文基于2014年7月23—24日10号台风麦德姆登陆前后福州降水的氢氧稳定同位素分析,发现台风麦德姆降水的δ¹⁸O变化范围为-7.2‰~-15.4‰,整个降雨过程分为3个阶段：阶段1（23日3：00至23日12：00）,雨水δ¹⁸O相对偏正（加权平均值为-7.8‰）,降水开始增加,主要受台风外围环流的影响;阶段2（23日12：00至24日8：00）,雨水δ¹⁸O显著偏负（加权平均值为-13.9‰）,采样点降水量达134.8 mm,约占观测时段降水量的78%,降雨量效应明显,主要受台风云雨区影响;阶段3（24日8：00至24日17：00）,雨水δ¹⁸O偏正（加权平均值为-9.2‰）,降水减少,台风远离福州。通过降水δ¹⁸O的阶段性特征以及过量氘,结合水汽输送通量与HYSPLIT-4模拟水汽轨迹分析,确定此次降水的水汽源主要来自西北太平洋水汽通道与孟加拉湾和南海水汽通道。     

填料在净化污水过程中渗透性能变化趋势的研究

选取腐殖垃圾和砂以及两者质量比分别为4:1、3:2、2:3的混合物共5种填料,在1.0 m/d的水力负荷下,进行人工快速渗滤系统净化生活污水的试验,研究填料在进水过程中渗透性能的变化趋势.结果表明,腐殖垃圾的初始饱和水力渗透系数(K)最大,为3.32×10-2cm/s,而砂的初始K只有5.14×10-3cm/s,腐殖垃圾含量越大的混合物其仞始K也越大.在净化污水的过程中,5种填料的K逐渐减小,腐殖垃圾含量越大的混合物其K降幅也越大.随着进水时间的延长,各个填料柱填料层50～250 mm处的水头损失占总水头损失(填料层50～450mm处)的比例均逐渐增加,最终各个填料柱均发生堵塞,堵塞均发生在填料层50mm以上范围内.     

昆明氮肥厂出台造气车间卫生管理条例

昆明氮肥厂针对职工只注重环境卫生而忽视设备卫生的现象,制定出台了《造气车间设备和环境卫生管理条例》。新《条例》已于1998年8月1日起正式实施。 新《条例》是根据国家有关劳动保护,安全生产法律、法规的规定,结合工厂的实际制定的。共分两则、九条,其主要内容有:第一则修理维修职责。第二则操作卫生职责。九条是:①坚持八小时工作制;②严格遵守检修规程;③加强对所属设备的认真巡回检查;④及时消除设备的跑冒滴漏;⑤正确使用设备,注重设备及室内外卫生;⑥液位工精心调节液位在三分之一至三分二之间;⑦炉前工认真巡回检查各炉坐板情况;⑧风机工认真检查风机运行情况;⑨脱硫工认真进行所属设备的巡回检查。     

环保电影，那些“难以忽视的真相”

虽然以环保为题材的电影仍属于大电影分类中的小众，不过我们有理由相信，随着越来越多的公民环保意识逐渐觉醒，环保类电影将有着更加广阔的发展空间。本文，将仅为大家介绍5部经典的环保题材电影和5部短片，这些电影背景不同却意义深刻，内容各异却影响深远。希望大家在闲暇时也能找几部来观赏一下，开阔视野，寓教于乐。     

施粉煤灰农田和作物的铜,钼,硒,钴和铍含量变化及影响评价

铜、钼、硒是钴是动植物和人体必需的微量元素，参与许多重要的生理新陈代谢过程，绝大多数植物对这些元素的忍受性也较强。粉煤灰中的这四种元素含量均较对照的高，但受土壤ｐＨ值和有机质含量等的影响，施灰田作物中这四种元素未有异常富集。     

5种水生植物去污抗逆能力的试验研究

在实验室人工模拟太湖地区初春较寒冷的气象条件下,对5种能越冬的水生植物(伊乐藻、微齿眼子菜、竹叶眼子菜、石菖蒲和水芹菜)在不同营养条件下去除氮磷的效果和一些反映其抗逆能力的生理生化指标进行了系统的对比研究.结果表明:这5种植物均能较好地吸收水中的营养物质,其中以水芹菜和微齿眼子菜的脱氮除磷效果最好;5种植物体内脯氨酸含量均与水体营养物质的质量浓度呈正相关,相同试验条件下,水芹菜和微齿眼子菜体内脯氨酸的积累倍数最高,表明二者的抗逆能力也较强;但当水体营养物质的质量浓度超过一定限值后,5种植物的生物量增长率均随水体营养等级的增高而下降.水芹菜和微齿眼子菜可作为构成双层次群落结构(FAMS)的优选植物种类,用于修复太湖地区富营养化水体.      

抗击冰雪灾害的具体措施

今年年初,中国南方地区发生了雨雪冰冻灾害,21个省、自治区受灾,死亡107人,失踪8人.170个县供电中断,经济损失1111亿元.虽然现在抗击这场灾害的斗争已经取得了阶段性胜利,但是认真总结教训,做好抗击这种灾害的准备,以防今后再有这种灾害发生,显得尤为重要.     

Differences in the quality of steamed hull-less barley and wheat cakes北大核心CSCD

In this study, three different hull-less barley varieties were used to prepare steamed cakes, and their nutritional value, sensory qualities, textural properties, and in vitro starch hydrolysis were evaluated. The results showed that the contents of total dietary fiber (4.50%-5.12%), β-glucan (2.96%-3.96%), total flavonoids (12.56-38.73 mg/100 g), and γ-aminobutyric acid (5.08-9.53 mg/100 g) in the steamed hull-less barley cakes were significantly higher than that in the steamed wheat cake, which were 0.65%, 0.23%, 3.93 mg/(100 g), and 2.63 mg/(100 g), respectively. The sensory properties of steamed ordinary hull-less barley and wheat cakes were not significantly different, but the steamed 08-1127 (waxy hull-less barley) cake was softer and out of shape. The springiness, resilience, cohesiveness, gumminess, and adhesiveness of steamed ordinary hull-less barley cakes were similar to those of steamed wheat cake, while those of steamed 08-1127 cakes were significantly lower than those of steamed ordinary hull-less barley cakes. Steamed hull-less barley cake also showed a maximum starch hydrolysis rate (38.76%-42.74%) that was lower than that of steamed wheat cake (49.92%), and the contents of rapidly (11.58%-13.16%) and slowly digested starch (5.34%-7.56%) were lower than that of steamed wheat cake (17.21% and 15.97%, respectively). In addition, the glycemic (59.37-61.67) and hydrolysis indexes (35.82-40.00) were lower than those of steamed wheat cake (76.66 and 67.30, respectively), and the contents of resistant starch (2.74%-3.55%) were higher than those of wheat steamed cake (1.68%). Therefore, the steamed cakes of ordinary hull-less barley had a higher content of nutritional components than the steamed cake of wheat, and the in vitro starch hydrolysis parameters were better than those of steamed wheat cake. When it is necessary to consider both nutritional and sensory qualities, ordinary hull-less barley can be selected as the raw material for steamed cakes, but waxy hull-less barley is not suitable for making steamed cakes. © 2022 Science Press. All rights reserved.