Comparison of mesophilic and thermophilic anaerobic digestions of thermal hydrolysis pretreated swine manure: Process performance, microbial communities and energy balance

Anaerobic digestion (AD) of swine manure (SM) commonly shows low biogas output and unsatisfactory economic performance. In this study, thermophilic AD (TAD, 50 ± 1 °C) was combined with thermal hydrolysis pretreatment (THP, 170 °C/10 bar), to investigate its potential for maximizing biogas yield, securing successful digestion and microbial diversity, as well as improving energy balance. Four lab-scale continuously stirred tank reactors were operated for 300 days and compared with each other, i.e., reactor 1 (raw SM fed in mesophilic AD: RSM-MAD), reactor 2 (THP-treated SM fed in MAD: TSM-MAD), reactor 3 (RSM-TAD), and reactor 4 (TSM-TAD). The results showed that THP was efficient to increase methane production of SM, TSM-TAD mode led to the highest methane yield (129.8 ± 40.5 mL-CH₄/g-VS/day) among the tests (p < 0.05). Although TAD was more likely to induce free ammonia (> 700 mg/L) or volatile fatty acids (> 6000 mg/L) accumulation compared with MAD in start-up phase, TSM-TAD treatment mode behaved a sustainable digestion process in a long-term operation. For TSM-TAD scenario, higher Shannon–Weaver (3.873) and lower Simpson index (0.061) indicated this mode ensured and enlarged the diversity of bacteria communities. Phylum Bathyarchaeota was dominant (59.3%−90.0%) in archaea community, followed by Euryarchaeota in the four reactors. RSM-MAD treatment mode achieved the highest energy output (4.65 GJ/day), TSM-TAD was less effective (−17.38 GJ/day) due to increased energy demands. Thus improving the energetic efficiency of THP units is recommended for the development of TSM-TAD treatment mode.     

城市户外热环境的舒适性研究

介绍了户外热环境舒适性评价的几种方法，提出了户外热环境舒适评价指标OTCD，指出了在室内OTCD能与PMV很好吻合，并且OTCD的各项参数便于测量。     

佳木斯台形变观测对东北地区几次浅震“场兆”异常的探讨

大地震在主破裂前往往行成地壳变形,高应力作用下进入峰值后的变形阶段,反映到地倾斜观测日均值曲线上,表现为固体潮形变趋势异常,这些异常能否指示远距离的地震,近年来不少研究者发现,远场前兆往往出现在对应力、应变变化反应灵敏的特殊构造部位。佳木斯台可能处于这种特殊的构造部位,对东北地区浅源地震短期前兆异常“场兆”的趋势性变化具有一定的意义。     

秦岭若干重要类型金矿床(体)快速定位预测

本文以西部秦岭地区八卦庙、双王、煎茶岭 3种重要类型金矿床为例 ,在成矿地质背景研究基础上 ,开展若干新方法新技术的找矿试验 ,研究发现 ,八卦庙式金矿岩石的烃含量与其金品位大致成正相关关系 ;而且金矿化强度和规模越大 ,相关系数值也越大 ;据此根据石英脉的烃含量对隐伏金矿床 (体 )和金矿化规模进行预测。双王式金矿原生晕的前缘晕元素为B、As、Sb、Hg,近矿晕元素为Au、Ba(-) ,尾晕元素为Mn、Bi。通过原生叠加晕垂向研究预测 ,双王和八卦庙金矿床现有的金矿体向下延伸还较大 ,在矿床的深部存在有盲矿体。煎茶岭式金矿的矿石铅同位素平均值比围岩要小 ,铅同位素曲线的低峰区往往就指示矿体所在 ;预测区的2 0 6Pb/ 2 0 4 Pb、2 0 8Pb/ 2 0 4 Pb比值变差椭圆图的形状和轴向斜率与已知矿区趋于一致 ,并且两者的变差椭圆图形大部分重叠 ,说明存在有同类型金矿体。以上研究成果为同期或后来的勘探工作或矿山采矿所验证。     

南昌台气氡异常核实

前兆观测资料异常产生的原因总体可分为两大类:观测物理量自身变化和外部因素影响,后者即通常所称的干扰.要提取出观测资料中有价值的震兆信息,必须首先将干扰剔除,但由于前兆干扰成因本身具有复杂性和多样性,并随不同测项、不同环境而存在个体差异,故要求异常核实工作深入、细致、全面、客观.本文通过一个实例,详细介绍了异常核实的思路和流程,并确定此次异常为仪器干扰,不属于震兆异常.     

城市草坪的生态热效益

分析了草坪的能量平衡机理以及与环境之间的热湿交换关系，说明了草坪对空气具有降温增湿作用。通过重庆市区一些草坪实测数据分析发现草坪日平衡温度与空气日平均温度相等，说明草坪与空气之间保持热量的生态平衡。     

南昌地震台地下水位变化异常的分析判别

本篇文章主要通过对南昌台地下水位资料变化的处理分析，利用求地下水水位变化的加速度来判别和分析地震异常，并初步进行试验预报和探索研究。     

电厂温排水对水库生态环境的影响

本文报告了电厂温排水对陡河水库生态环境的影响。结果表明,陡河水库年均水温比对照水体洋河水库提高2.8～4.8℃。溶解氧随着水温而变化,但从未低于5.0mg/l,增温后水体中各种营养盐类含量呈增加趋势,水体富营养化明显。     

An assessment of how distance and diesel oxidation catalyst will impact thermal decomposition behaviors of particles

Decomposition mass loss and pyrolysis products analyses of particles sampled at various locations along the tailpipe of a Euro-IV diesel engine were performed using a thermogravimetry in conjunction with Fourier transformation infrared spectrometry-mass spectrum. Diesel particles were collected at the same location with and without diesel oxidation catalyst (DOC) mounted on the test engine separately. The three poles in thermal gravity-differential thermal gravity images suggested that the decomposition process of diesel particles could be divided into three stages which correspond to the decompositions of lower boiling substances, higher boiling substances and soot respectively. It is noticed that no matter whether DOC was mounted or not, the further the particles were sampled away from the engine block, the lower the peak temperatures and the heavier the mass losses within the first two stages, which indicated that the soluble organic fraction in the particle samples increased and therefore lowering the activation energy of thermal decomposition. Hydroxyl, ammonia, C_xH_y fragments, benzene, toluene, and phenol were found to be the primary products of particle decomposition, which didn't change with the location of particle sample point. The employment of DOC increased the activation energy for particle oxidation and resulted in a higher peak temperature and lower mass loss within the first-stage. Moreover, the CO stretching bands of aldehyde and ketone at 1771 cm^?1 was only detected without a DOC, while the NO₂ peak at 1634 cm^?1 was solely noticed with the presence of DOC. Compared to the first-stage pyrolysis products, more polycyclic aromatic hydrocarbons and less C_xH_y fragments were seen in the second-stage.     

McCaffrey等估计轰燃前火灾温度方法的改进

在估计室内轰燃前火灾温度的多种方法中，McCaffrey等人提出的方法比较典型。该文根据内衬材料的热惯性对室内火灾的重要影响，在大量实验数据的基础上，对McCaffrey等人提出的这一方法进行了初步和理论上的改进；结合室内火灾的控制因素，对有机玻璃火灾的回归结果进行了进一步改进，提出了估计室内轰燃前火灾温度的新方法。