Effects of sodium bisulfate on alcohol, amine, and ammonia emissions from dairy slurry

Sodium bisulfate (SBS) is extensively used in the poultry industry to reduce ammonia and bacterial levels in litter. It is also used in the dairy industry to reduce bacterial counts in bedding and ammonia emissions, preventing environmental mastitis and calf respiratory stress. The present study measured the effect of SBS on the air emission of ammonia, amine, and alcohol from a dairy slurry mix. Amine flux was undetectable (<5 ng L(-1)) across treatments. Application of SBS decreased ammonia, methanol, and ethanol emissions from fresh dairy slurry. Ammonia emissions decreased with increasing levels of SBS treatment. The 3-d average ammonia flux from the control (no SBS applied) and the three different SBS surface application levels of 0.125, 0.250, and 0.375 kg m(-2) were 513.4, 407.2, 294.8, and 204.5 mg h(-1) m(-2), respectively. The ammonia emission reduction potentials were 0, 21, 43, and 60%, respectively. Methanol and ethanol emissions decreased with an increase in the amount of SBS applied. The 3-d average methanol emissions were 223.7, 178.0, 131.6, and 87.0 mg h(-1) m(-2) for SBS surface application level of 0, 0.125, 0.250, and 0.375 kg m(-2), with corresponding reduction potentials of 0, 20, 41, and 61, respectively. Similar emission reduction potentials of 0, 18, 35, and 58% were obtained for ethanol. Sodium bisulfate was shown to be effective in the mitigation of ammonia and alcohol emissions from fresh dairy slurry.     

Alcohol, volatile fatty acid, phenol, and methane emissions from dairy cows and fresh manure

There are approximately 2.5 million dairy cows in California. Emission inventories list dairy cows and their manure as the major source of regional air pollutants, but data on their actual emissions remain sparse, particularly for smog-forming volatile organic compounds (VOCs) and greenhouse gases (GHGs). We report measurements of alcohols, volatile fatty acids, phenols, and methane (CH4) emitted from nonlactating (dry) and lactating dairy cows and their manure under controlled conditions. The experiment was conducted in an environmental chamber that simulates commercial concrete-floored freestall cow housing conditions. The fluxes of methanol, ethanol, and CH4 were measured from cows and/or their fresh manure. The average estimated methanol and ethanol emissions were 0.33 and 0.51 g cow(-1) h(-1) from dry cows and manure and 0.7 and 1.27 g cow(-1) h(-1) from lactating cows and manure, respectively. Both alcohols increased over time, coinciding with increasing accumulation of manure on the chamber floor. Volatile fatty acids and phenols were emitted at concentrations close to their detection limit. Average estimated CH4 emissions were predominantly associated with enteric fermentation from cows rather than manure and were 12.35 and 18.23 g cow(-1) h(-1) for dry and lactating cows, respectively. Lactating cows produced considerably more gaseous VOCs and GHGs emissions than dry cows (P < 0.001). Dairy cows and fresh manure have the potential to emit considerable amounts of alcohols and CH4 and research is needed to determine effective mitigation.     

Development of a unique topology for a hard-turning micro-scale machine tool

A micro-scale machine tool (mMT) topology is developed for turning hardened steel bearing components. The topology utilizes the principle of leverage to increase accuracy and stiffness and incorporates decoupling to reduce unwanted motion of the tool. Performance specifications required that the static stiffness is at least 10 N/μm and dynamic stiffness is at least 30 N/μm in all directions. The kinematics for the topology are developed to enable control over the position and orientation of the tool tip. The effect of the topology on rake angle is determined and the topology is adjusted so as to minimize the rake angle variation during the cut. Cutting tests are performed to determine cutting parameters for achieving a low surface roughness and to estimate the accuracy of the machine. Tests show that the hard-turning mMT can achieve surface roughness below 25 nm Ra, diametrical accuracy of 1 μm and peak-to-valley roundness deviation (RONt) below 0.35 μm.     

Improved preparation of small biological samples for mercury analysis using cold vapor atomic absorption spectroscopy

Concentrations of mercury in biological samples collected for environmental studies are often less than 0.1 microgram/g. Low mercury concentrations and small organ sizes in many wildlife species (approximately 0.1 g) increase the difficulty of mercury determination at environmentally relevant concentrations. We have developed a digestion technique to extract mercury from small (0.1 g), biological samples at these relevant concentrations. Mean recoveries (+/- standard error) from validation trials of mercury fortified tissue samples using cold vapor atomic absorption spectroscopy for analysis ranged from 102 +/- 4.3% (2.5 micrograms/L, n = 15) to 108 +/- 1.4% (25 micrograms/L, n = 15). Recoveries of inorganic mercury were 99 +/- 5 (n = 19) for quality assurance samples analyzed during environmental evaluations conducted during a 24 month period. This technique can be used to determine total mercury concentrations of 60 ng Hg/g sample. Samples can be analyzed in standard laboratories in a short time, at minimal cost. The technique is versatile and can be used to determine mercury concentrations in several different matrices, limiting the time and expense of method development and validation.     

有害结局路径(AOP)框架在水体复合污染监测研究中的应用

水体复合污染包含低浓度、种类复杂的毒害化学污染物,威胁人类健康和生态安全。监测并识别水体关键毒害污染因子是进行水质管理的前提,也是复合污染研究的难点。目前国内外在水复合污染毒性监测研究上主要基于动物活体试验或者生物体外测试。由于受限于毒理学测试方法,常见的应用通常仅关注于某方面的毒性效应或者少数的分子指标,因而受到质疑和挑战。有害结局路径(Adverse outcome pathway,AOP)的概念将化学污染物的结构、致毒的分子启动事件和生物毒性的有害结局建立关联,为污染物的毒性测试、预测和评估提供了新的模式。本文旨在论述有害结局路径在复合污染毒性评估和关键毒害物质鉴别中的指导性价值和意义。在有害结局路径的指导框架下,借助于生物体外高通量测试技术、化学分析的靶向和非靶向分析技术和生物信息学技术,可以系统地分析化学混合物在分子、细胞水平上健康相关指标的响应水平,评估水体中复杂结构污染物,与不同生态和健康有害结局之间的关联,为水环境评价和优先污染物的筛选管理提供有效支撑。本文通过综述AOP框架在复合水体中毒害物质风险研究的现状和优势,对AOP在水环境环境管理上的应用前景提出展望。     

Application of CFD modelling to air quality in Kuwait City

High-resolution computational fluid dynamics (CFD) simulations have been performed to assess the dispersion of air pollutants (CO₂) emanating from traffic in a busy street and in the vicinity of a complex configuration of buildings located in Salmiya, Kuwait City. New buildings are planned for this area, and the work here includes predictions for the dispersion of pollutants after the buildings’ completion. The CFD simulations are based on calculated CO₂ concentration levels for traffic counts taken on location in Salmiya with the existing configuration of buildings. As the computer code used in this work has been evaluated previously, it will be applied here to predict with confidence any potential air pollution problem areas on the addition of the new buildings. It was found for very light wind, that the proposed new buildings help reduce pollution in the vicinity of residential buildings within the configuration of buildings, but as the wind becomes moderate to strong, there was a tendency for the pollutant to get trapped in the residential area. Results are given for both exceptionally high ambient temperatures and very light wind, which are not often reported in studies found in the literature.     

Interactive effects of male and female age on extra-pair paternity in a socially monogamous seabird

Females sometimes obtain older sires for their offspring through extra-pair interactions, but how female age influences paternity is largely unexplored and interactive effects across the age span of both sexes have not been analyzed. To test whether female choice of sire age varies with female age in the blue-footed booby (Sula nebouxii), we examined associations between ages of both partners and the probability of extra-pair paternity (EPP) in 350 broods of parents up to 22 years old in a single breeding season. Extra-pair paternity enables a female to select an alternative sire for her offspring and could function to avoid or achieve particular combinations of parental ages. A male age?×?female age interaction revealed that in young females (≤4 years), EPP decreased with increasing age of the social partner, whereas in old females (≥8 years), it increased. Moreover, sires of extra-pair (EP) chicks of young females paired to young males were on average 6.33 years older than the females’ social partners. Since female boobies control copulatory access, this pattern could imply that young females choose old sires for their proven genetic quality and that old females avoid very old males because matings with them may risk infertility or genetic defects in offspring. Taking female age into account and observing across the whole age span may be necessary for understanding female age-based mate choice.     

Combination of the direct electro-Fenton process and bioremediation for the treatment of pyrene-contaminated soil in a slurry reactor

A combined treatment technology (DEF-BIO) using the direct electro-Fenton (DEF) process and bioremediation (BIO) was established in this study. The performance of the DEF-BIO process on the remediation of a pyrene (PYR)-contaminated soil was evaluated in a slurry reactor. The appropriate order of application was to conduct the DEF process followed by BIO, evaluated through analysis of the degradation characteristics of each process individually. In addition, the application time of the DEF process affected the efficiency of the combined process. The optimum time to apply the DEF process was determined through an analysis of the induced changes in PYR intermediates, pH, soil organic matter (SOM) and bacteria. The optimum application time of the DEF process was 6 h. All the induced changes were beneficial for the BIO phase. The removal of PYR was 91.02% for DEF–BIO after 72 h, and the efficiency was almost 50% increased, compared with the individual DEF and BIO treatments. Therefore, the combined process of DEF–BIO process may be an efficient and promising method for the remediation.