作者希望承认艾伦-克鲁格, 托德博蔓, 香农 Ostdiek, 伊莱恩浆果, 和 Ferouz Ayadi 谁协助数据收集使用模拟层包。撰文人还认识到泰咪-Brandl 和戴尔 Janssen 协助维持环境分庭的情况。

这项研究的目的是在42天内进行每周数据收集。所有的动物程序都是由美国肉类动物研究中心机构动物护理和使用委员会审查和批准的。
1. 构建模拟层包
<ol><li>开始与塑料圆筒容器是 0.42 m 高与 0.38 m 直径。 注: 在这项研究中, 使用了一个特定的10加仑商业垃圾箱 (见材料表), 但其他类似大小的塑料容器是合适的。</li>
	<li>钻六1厘米孔均匀地间隔在塑料容器的圆周附近入每个塑料容器大约 5 cm 塑料容器的顶部。从容器中取出任何塑料残余物。</li>
	<li>将塑料容器包装, 并在塑料容器的侧面记录质量。用平衡的方法将所选床上用品的320克称量成称重锅, 并将床上用品材料添加到塑料容器中。 注: 可使用9、10、11、12、13、14、15所认为适合在畜牧设施中使用的任何床上用品材料。对于上层大平原的深层牛设施建模, 玉米秸秆被认为是最常见的床上用品材料1 , 但大豆秸秆、麦草、木片也被使用了1。如果使用该系统建模深层猪或乳品设施, 麦草, 大麦秸秆, 燕麦稻草, 干草, 木屑, 木片, 木屑, 报纸, 玉米棒子, 大豆茬, 稻壳, 或沙子可能更适合16,17 ,18。</li>
	<li>将320克的新鲜牛粪在塑料板材上使用平衡并添加到塑料容器中。 注: 尿和粪收集和维护如前所述11。</li>
	<li>测量320毫升新鲜牛尿在 1000年-毫升毕业圆筒。将空的内容放入塑料容器中。使用搅拌杆 (5.08 厘米圆周), 混合的床上用品材料混合物略有三十年代。 注: 在这种情况下, 使用了一个塑料盖在年底空心钢棒。或者, 可以使用任何类型的杆。</li>
	<li>使用防腐处理擦拭, 清洁每层包间搅拌杆的末端, 防止微生物交叉污染。 注: 一桶温水肥皂水也可以用来清洁搅拌棒。塑料三明治袋也可以用橡皮筋固定在杆的末端, 并在每层包后更换, 以防止交叉污染。</li>
	<li>权衡和记录床上用品混合物的最终质量。放置塑料容器在环境房间19设置到环境温度 18-20 °c 与露点12°c。</li>
</ol>2. 维护模拟层包
<ol><li>在添加粪便和尿液前四十八小时, 从冷冻库中取出冰冻粪便和尿液, 并允许室温解冻 (20-25 ˚C)。</li>
	<li>在将尿液加到层状包装前不到一个小时, 测量尿液的 pH 值。</li>
	<li>用适当的个人防护设备 (手套, 安全眼镜) 处理6米氢氧化钠。</li>
	<li>将25毫升的氢氧化钠 (氢氧化钠) 倒入已毕业的圆筒中。搅拌混合物, 然后用 ph 探针测试 ph 值。重复直到尿液达到 ph 值 7.4, 生理 ph 值20。</li>
	<li>一旦尿液 pH 值调整, 在不使用的情况下, 在尿液容器上更换瓶盖以防止尿液中氮的挥发。</li>
	<li>称量并记录下层包的质量。如果要在这一天添加新的床上用品, 将320克的选择床上用品的材料分为铝锅使用平衡, 并添加床上用品材料的各自层包。如果今天不添加床上用品, 请继续步骤2.7。</li>
	<li>用平衡的方法在塑料板上重320克的解冻牛粪, 并添加到层状包中。 注: 在21天, 使用新鲜的粪便, 而不是解冻的粪便。</li>
	<li>测量320毫升解冻牛尿在 1000年-毫升毕业圆筒。空的内容放到层层包上。 注: 在21天, 使用新鲜的尿液而不是解冻的尿液。</li>
	<li>使用搅拌杆, 搅拌床上用品包混合物轻微30秒。清洁每层包间搅拌杆的塑料端, 防止微生物交叉污染。权衡和记录床上用品混合物的最终质量。</li>
	<li>将塑料容器退回环境舱。</li>
	<li>重复步骤 2.1-2.10 在星期一, 星期三和星期五每周, 与床上用品材料被添加 (步骤 2.6) 和空气样本收集每个星期三。</li>
</ol>3. 从模拟层包中采集样品
注: 样品是收集从模拟层包每周一次, 在添加粪便, 尿液, 和新鲜的床上用品。
<ol><li>准备收集每个模拟层包顶空的空气样本。
	<ol>
<li>打开所有的空气取样设备, 并允许根据制造商的指示预热, 大约1小时。 注: 参见本研究中使用的氨 (NH3)、硫化氢 (H2)、甲烷 (CH4)、一氧化二氮 (N2O) 和二氧化碳 (CO2) 气体分析仪的材料表。</li>
		<li>测量从模拟的层状包顶部到塑料容器顶部的距离, 它使用标尺来保存模拟的层状包。</li>
		<li>使用以下公式计算顶空区域的体积: <img alt="Equation 1" src="/files/ftp_upload/57332/57332eq1.jpg"> 其中r = 塑料容器的半径, h = 从层状包顶部到塑料容器顶部的距离, 以及 V通量室 = 流量室的体积位于塑料容器的顶部。 注: 本研究使用的通量室的内部容积为 0.007m3 , 表面面积为0.064 米21,22。</li>
		<li>在包的近似中心, 将金属木桩推入层状包的表面大约5厘米。螺纹0.64 厘米惰性油管通过在每个模拟的层状包装容器顶部的1厘米孔中的一个, 并在所述床上用品包表面上方的12.5 厘米金属木桩上固定。将不锈钢半球静止通量室21,22 , 每个模拟层包顶部有橡胶裙 (图 1)。 注: 橡胶裙是由61厘米的软、弹性橡胶制成, 其直径为22.9 厘米, 在中心切割。孔适合在通量室和裙子在塑料容器的顶部形成封印, 当放置在容器。</li>
		<li>使用惰性压缩接头将0.64 厘米的惰性油管连接到焊剂室。 注: 惰性油管附着在气体取样流形上, 流入空气取样设备。气体取样系统由24伏可编程逻辑继电器 (见材料表) 控制, 信号多位置3路螺线管打开和关闭气体取样流形上的八个进气线之一。一次打开一条线, 允许每个层包中的单个空气取样。</li>
		<li>以5升-1分钟的速度从房间里冲洗空气, 用30分。 注: 请参阅用于通过样品线冲洗空气的泵材料表。</li>
	</ol></li>
	<li>测定模拟层状包顶空气中氨、二氧化碳、甲烷和硫化氢的浓度。
	<ol>
<li>在充分冲洗模拟的层状包后, 在取样线上打开旋塞阀, 将室内空气从房间抽出到与气体取样歧管连接的惰性试样线上。</li>
		<li>激活可编程逻辑继电器, 开始将空气抽入空气取样设备。从周围空气中记录测量20分钟以确定环境空气中测量气体的浓度。这将被用作背景空气浓度。完成收集环境空气浓度后, 关闭样品线上的旋塞阀。</li>
		<li>激活可编程逻辑中继, 开始从连接到每个通量室的惰性试样线取样空气。记录每条取样线的测量值20分钟, 以确定每个层状包顶空的测量气体浓度。</li>
		<li>结果可以被报告作为气体的平均集中 (NH3, CO2, N2O, CH4, H2S) 在空气样品 (毫克公斤-1或 ppm), 或者气体的通量密度 (发射率) 可以计算在质量每单位使用以下公式计算每个单位时间的面积: <img alt="Equation 2" src="/files/ftp_upload/57332/57332eq2.jpg"> 其中J = 通量在µg m-2分钟-1, A = 在房间内的来源 (m2) 的区域, Q = 扫气流速率 m3分钟-1, 并 C空气 = VOC 浓度离开房间 (µg m-3)23。</li>
	</ol></li>
	<li>测定模拟层状包顶空气中恶臭挥发性有机化合物的浓度。
	<ol>
<li>戴上乳胶或腈一次性手套。</li>
		<li>在充分冲洗模拟的层状包装后, 从预预处理的不锈钢吸附剂管中取出黄铜储存帽。 注: 本研究使用的吸附剂管为89毫米 x 6.4 毫米的外径, 填充管 TA 吸附剂 (见材料表)。黄铜帽有 polythtrafluorethylene (PTFE) 套圈。</li>
		<li>使用挠性橡胶管, 将吸附管的得分端连接到通量室的入口口, 并将该吸气管的另一端与真空泵结合。 注: 本研究中使用的真空泵 (见材料表) 通过吸附剂管以75毫升最小-1的流速拉动空气。</li>
		<li>允许泵将空气拉入吸附剂管中5分钟, 样品容积为0.375 升, 然后关闭泵并断开吸附剂管。更换吸附管两端的黄铜储存帽。</li>
		<li>重复步骤 3.3.1 3.3.4 收集每层包的一个吸附剂管。</li>
		<li>储存吸附剂管直到通过热解吸-气相色谱-质谱 (TD-gc-ms) 分析。管可储存在室温下 (20-25 ˚C) < 24 小时。如果储存 > 24 小时, 储存在冰箱里。</li>
		<li>在对 TD-GC-MS 系统进行样品分析之前, 先从吸附剂管中取出黄铜储存帽, 并用 PTFE 分析帽23代替。</li>
		<li>分析挥发性有机化合物的吸附管24 (醋酸, 丁酸, 丙酸, 丙酸, 异戊酸, 戊酸, 己酸, 庚酸, 苯酚, 对甲酚, 吲哚, 粪臭素, 二甲基二硫, 和二甲基三硫醚) 使用 TD-GC-MS23,24,25。</li>
		<li>结果可以报告为空气中挥发性有机化合物的浓度 (µg m-3), 或的流量密度 (排放率) 的 voc 可以计算每单位面积的质量, 单位时间的基础上使用以下方程式: <img alt="Equation 2" src="/files/ftp_upload/57332/57332eq2.jpg"> 其中J = 通量在µg m-2分钟-1, A = 在房间内的来源 (m2) 的区域, Q = 扫气流速率 m3分钟-1, 并 C空气= VOC 浓度离开房间 (µg m-3)23。</li>
	</ol></li>
	<li>收集模拟层包的物理和化学测量。 注: 每次将附加材料添加到模拟的层状包中时, 温度、pH 值和蒸发失水量都被测量。营养成分在0天和42天确定。自由空气空间在42天仅被确定。<ol>
<li>通过将温度探头插入到层状包的中心, 大约7.6 厘米, 在模拟的床包表面下方, 确定所述平面包的温度。允许温度稳定和记录。</li>
		<li>确定蒸发水损失估计数<ol>
<li>把塑料容器放在天平上。</li>
			<li>测量和记录在每添加粪便/尿/寝具之前和之后的模拟层包的质量。</li>
			<li>通过从前一天的结束质量中减去当前天的起始质量来计算估计的蒸发水损失。不同的是, 估计的水量从层间的包中蒸发了几天, 可以用来比较层状包之间的相对差异, 虽然它并不反映绝对损失。</li>
		</ol>
</li>
		<li>测定模拟层状包的 pH 值<ol>
<li>收集一个代表性的 5-10 克样品从每个模拟的层状包装从中心的包在深度约7.6 厘米的表面下的层状包。将样品放入塑料50毫升锥形管、瓶盖和标签中。</li>
			<li>根据制造商的指示, 校准 ph 值为4和7的酸碱度表。</li>
			<li>确定每个圆锥的质量。</li>
			<li>用蒸馏, 去离子水稀释每个样品1:2 在大量基础上。摇动锥形混合水和床上用品材料。将 ph 探针插入锥形, 测量, 并记录样品的 ph 值。</li>
		</ol>
</li>
		<li>仅在0和42天, 确定模拟的层状包的养分含量。<ol>
<li>收集一个50克代表性的样品从每一个模拟的层状包装从中心的包在深度约7.6 厘米的表面下的床包。放置在纸土样品袋中。</li>
			<li>在24小时内运送到实验室进行营养分析。储存在冰箱里, 直到样品可以运到实验室进行营养分析。 注: 任何宏观或微量营养素都可以分析。我们分析了27在一个商业实验室的总氮26, 磷和硫磺分析。</li>
		</ol>
</li>
		<li>仅在42天, 确定模拟层包中的自由空气空间。<ol>
<li>将塑料容器置于平衡处, 并记录质量。慢慢地填满水, 直到水面甚至与模拟的层状包的表面。允许水定居, 直到没有更多的气泡来自模拟层包, 然后记录的质量塑料容器</li>
			<li>使用以下计算确定可用空空间的百分比: <img alt="Equation 3" src="/files/ftp_upload/57332/57332eq3.jpg">
</li>
		</ol>
</li>
	</ol></li>
	<li>完成所有需要的数据收集步骤 (步骤 3.1-3.4) 后, 将粪便、尿液和寝具添加到经过 2.1-2.10 步的模拟层包中。</li>
</ol>

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Qual. 43, 1187-1194 (2014).</li><li>Spiehs, M. J., Brown-Brandl, T. M., Berry, E. D., Wells, J. E., Parker, D. B., Miller, D. N., Jaderborg, J. P., Diconstanzo, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Use+of+wood-based+materials+in+beef+bedded+manure+packs:+2.+Effect+on+odorous+volatile+organic+compounds,+odor+activity+value,+Escherichia+coli,+and+nutrient+concentration.">Use of wood-based materials in beef bedded manure packs: 2. Effect on odorous volatile organic compounds, odor activity value, Escherichia coli, and nutrient concentration.</a> J. Environ. Qual. 43, 1195-1206 (2014).</li><li>Spiehs, M. J., Brown-Brandl, T. M., Parker, D. B., Miller, D. N., Berry, E. D., Wells, J. 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Qual. 46, 722-732 (2017).</li><li>Herbert, S., Hashemi, M., Chickering-Sears, C., Weis, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Bedding options for livestock and equine. , (2008).</li><li>Effects of bedding on pig performance. Iowa State Research Farm Progress Reports Available from: <a target="_blank" href="https://lib.dr.iastate.edu/farms_reports/134/">https://lib.dr.iastate.edu/farms_reports/134/</a> (2012)</li><li>Brown-Brandl, T. M., Nienaber, J. A., Eigenberg, R. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Temperature+and+humidity+control+in+indirect+calorimeter+chambers.">Temperature and humidity control in indirect calorimeter chambers.</a> Trans. ASABE. 54, 685-692 (2011).</li><li>Abney, C. S., Vasconcelos, J. T., McMeniman, J. P., Keyser, S. A., Wilson, K. R., Vogel, G. J., Galyean, M. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effects+of+ractophamine+hydrochlodride+on+performance,+rate+and+variation+in+feed+intake,+and+acid-base+balance+in+feedlot+cattle.">Effects of ractophamine hydrochlodride on performance, rate and variation in feed intake, and acid-base balance in feedlot cattle.</a> J. Anim. Sci. 85, 3090-3098 (2007).</li><li>Miller, D. N., Woodbury, B. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+solid-phase+microextraction+chamber+method+for+analysis+of+manure+volatiles.">A solid-phase microextraction chamber method for analysis of manure volatiles.</a> J. Environ. Qual. 35, 2383-2394 (2006).</li><li>Woodbury, B. L., Miller, D. N., Eigenberg, R. A., Nienaber, J. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=An+inexpensive+laboratory+and+field+chamber+for+manure+volatile+gas+flux+analysis.">An inexpensive laboratory and field chamber for manure volatile gas flux analysis.</a> Trans. ASABE. 49, 767-772 (2006).</li><li>Koziel, J. A., Spinhirne, J. P., Lloyd, J. D., Parker, D. B., Wright, D. W., Kuhrt, F. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Evaluation+of+sample+recovery+of+malodorous+livestock+gases+from+air+sampling+bags,+solid-phase+microextraction+fibers,+Tenax+TA+sorbent+tubes,+and+sampling+canisters.">Evaluation of sample recovery of malodorous livestock gases from air sampling bags, solid-phase microextraction fibers, Tenax TA sorbent tubes, and sampling canisters.</a> J. Air Waste Manag. Assn. 55, 1147-1157 (2005).</li><li>Parker, D. B., Gilley, J., Woodbury, B., Kim, K., Galvin, G., Bartelt-Hunt, S. L., Li, X., Snow, D. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Odorous+VOC+emission+following+land+application+of+swine+manure+slurry.">Odorous VOC emission following land application of swine manure slurry.</a> Atmos. Environ. 66, 91-100 (2013).</li><li>Parker, D. B., Koziel, J. A., Cai, L., Jacobson, L. D., Akdeniz, N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Odor+and+odorous+chemical+emissions+from+animal+buildings:+Part+6.+Odor+activity+value.">Odor and odorous chemical emissions from animal buildings: Part 6. Odor activity value.</a> Trans. ASABE. 55, 2357-2368 (2012).</li><li>Watson, M., Wolf, A., Wolf, N., Peters, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Total+nitrogen.">Total nitrogen.</a> Recommended methods of manure analysis. , 18-24 (2003).</li><li>Wolf, A., Watson, M., Wolf, N., Peters, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Digestion+and+dissolution+methods+for+P,+K,+Ca,+Mg,+and+trace+elements.">Digestion and dissolution methods for P, K, Ca, Mg, and trace elements.</a> Recommended methods of manure analysis. , 30-38 (2003).</li><li>Euken, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+survey+of+manure+characteristics+from+bedded+confinement+buildings+for+feedlot+beef+productions:+Progress+report.">A survey of manure characteristics from bedded confinement buildings for feedlot beef productions: Progress report.</a> Animal Industry Report. , (2009).</li><li>Li, L., Li, Q. -. F., Wang, K., Bogan, B. W., Ni, J. -. Q., Cortus, E. L., Heber, A. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+National+Air+Emission+Monitoring+Study's+southeast+layer+site:+Part+I.+Site+characteristics+and+monitoring+methodology.">The National Air Emission Monitoring Study's southeast layer site: Part I. Site characteristics and monitoring methodology.</a> Trans. ASABE. 56, 1157-1171 (2013).</li></ol>

这项研究由联邦拨款资助给美国农业部农业研究服务, 研究项目编号3040-41630-001-00D。
在本文中提及商号或商业产品, 纯粹是为了提供具体的信息, 并不意味着美国农业部的推荐或认可。
美国农业部是一个平等机会提供者和雇主。

经常增加尿和粪便对层状的包是一个关键步骤。我们试验了一次添加尿和粪便, 只是每周一次, 但发现, 该层包开发了一个地壳, 其中捕获的气体包内, 并没有代表的商业设施。在研究开始时使用新鲜粪便可确保所用的层状包接种在牛设施中发现的常见细菌种群。当添加尿液时, 要记住调整 ph 值到生理 ph 值, 然后再添加到层状包中也是很重要的。有一次, 出现了一个错误, 并将低 pH 值的尿液添加到层状包中。这就杀死了甲烷菌群。在建立气体取样系统时, 所有配件都需要安全, 以防止泄漏可能危及气体测量的质量。
该议定书自第一次开发以来就已加以修改。将静态通量室调整为动态通量室使研究人员能够计算出排放量, 而不是在顶空气体中的浓度。使用新的动态气体取样系统还允许一个人完成抽样, 而不是需要三人来管理所有的数据收集。
可以使用模拟的层状包来评估在猪或乳品设施中使用的床上用品材料或气味修正。需要作出调整以确定适当的床上用品: 猪或乳品设施中典型的粪便比率。发表的文献应提供商业猪或乳制品设施的干物质和营养成分的期望, 这将有助于估计需要调整模拟层状包的床上用品、粪便和尿量。代表猪或乳品设施的协议。该议定书从未被用来测量无机床上用品材料, 如沙子, 通常用于乳品设施。虽然没有理由相信它不会成功地测量含有无机床上用品材料的层状包装的气体排放量, 但这需要额外的测试。
可能有额外的气体, 可以取样, 我们没有评估。在理论上, 任何可以附着在惰性气体取样线上的气体取样仪器都应该能够与这个系统一起使用。
该模型还可以调整, 以探索不同的床上用品: 肥料比率, 如果研究员选择这样做。也许研究人员对确定在发现重大气味之前可以添加到一层包中的粪便或尿液的最大数量感兴趣。或研究员想检查不同的温度和湿度对空气质量的影响。该模型也可以调整, 以检查这些因素。
该议定书的制定, 以测量空气质量和营养成分从实验室规模的层状包装在一个受控环境, 并已被用来有效地评估许多不同的床上用品材料, 环境变量 (温度, 湿度),和潜在的缓解措施, 可以改善商业深层单坡设施的空气质量。该模型是动态的, 使研究人员可以轻松地收集许多化学和物理测量从层状包, 包括 NH3, CH4, N2O, CO2, H2S, VOC, 温度, pH 值, 营养成分, 自由空气空间, 以及可能还没有被测量的其他人。每周在六至七周内收集的测量结果, 让我们有足够的时间看到随着层状包装的成熟, 空气质量测量的变化。从模拟的层状包收集的数据是在以前测量的商业深层单坡设施的浓度范围内。过去的研究表明, 每项治疗的 8-10 个实验单位足以检测模拟层包9,10,11,12之间的统计差异, 13,14,15。这些层状的包很容易维护, 每层包每周需要少于10分钟的人工添加尿液、粪便和寝具。根据收集的测量结果, 使用气体取样系统采集样品需要每层包 20-30 分钟。过去, 一个人在正常的8小时工作日里分析了多达20层的包层。利用实验室规模的层状包, 研究者可以控制在研究或商业设施中难以或不可能控制的温度、湿度和床上用品来源等变量。一些实验室规模的研究可以进行, 以消除可能的治疗之前, 尝试在研究或商业规模的设施。
模型的主要局限性是, 它不是一个完美的模拟 "现实世界" 条件。很难完全模拟商业条件, 例如在牲畜设施中不断增加的尿液和粪便。根据与商业设施比较的模拟层包的干物质含量和营养成分, 以及我们实验室的劳动力, 我们已经确定了三次每周增加尿和粪便, 以充分利用。然而, 如果可以制定一个修改, 定期增加新鲜尿和粪便每天多次, 这将更好地模拟商业环境。
另一个公认的限制是使用冰冻和解冻的粪便和尿液。虽然尽一切努力快速冻结尿液和粪便, 以防止氮的挥发和任何细菌的生长, 从平衡研究收集的尿和粪便只每天收集一次。收集、称量、重置收集容器, 并对尿液和粪便进行分割, 需要一个小时或更长时间。它还需要几个小时的 20 L 卡博尿完全冻结, 即使被放置在-4 ˚C 冷冻机。在这段时间内, 挥发和细菌的生长可能会发生。为弥补这一延迟收集和冻结之间的时间延误, 尿液是酸化的 pH 值4后立即从收集装置取出容器, 以防止细菌生长和氮挥发。尿液恢复到 pH 值 7, 一旦解冻, 但这可能不完全一样, 添加新鲜的尿液。然而, 由于没有观察到 NH3挥发的增加, 加上新鲜尿液与冰冻尿液相比, 我们相信我们已经尽量减少这一限制。当粪便结冰时, 细菌的数量会被杀死或减少。这是我们通过在0天和21天增加新鲜粪便而试图减少的议定书的公认限制。
使用一个钢棒来温和混合的新添加的粪便和尿与床上用品材料可能无法完美地模拟牛的重量, 在一个商业设施, 从而造成了一些不同的压实和水保持能力。为了说明层状背的孔隙度, 并作为层状包装中可能存在的自由空气空间的指示, 在每项研究结束时, 水被倒入层状包中, 以确定每个层状包装9中的自由空气空间百分比.0 >>,10,11,12,13,14,15。自由的空气空间一般保持均匀从一项研究到另一个, 但没有被比作是在一个商业设施中的自由空气空间。
该议定书尚未与其他牲畜种类或设施类型进行测试, 如猪深层箍或瑞典深层产仔设施、乳制品堆肥仓或其他奶制品设施, 或使用床上用品的任何类型的家禽设施。虽然该模式似乎有可能被用作其他牲畜设施的样板, 但对《议定书》的调整可能是必要的, 足以代表在肉牛深层设施之外的任何设施。
虽然该模型不是一个完美的模拟商业设施, 它可以提供一个出发点, 当评估的因素, 如床上用品, 温度, 湿度, 或修正, 可添加到一个层状包装的牲畜设施。它允许研究人员评估在受控环境中的治疗差异, 并在花费资金用于全面商业规模操作所需的资源之前消除潜在的更有效的治疗方案。

在中西部和上大平原, 肉牛禁闭设施是一种受欢迎的住房选择。在这个地区, 禁闭设施比南部平原更常见, 因为该地区每年都会有更多的降水, 从而造成更多的饲养场径流, 必须加以遏制。许多生产者选择为肉牛建造单坡谷仓。生产者选择单一斜坡设施的主要原因是能够安排人工和粪便的去除, 并且比开放地段饲养场1的性能改善。大多数牛生产者 (72.2%) 使用单坡谷仓维持一个层状包为一轮牛或更长的, 使用一个深床上用品管理系统的床上用品和废料1。最常见的床上用品材料是玉米秸秆, 虽然生产者报告使用大豆茬, 小麦秸秆, 玉米棒子, 木屑1。由于区域对玉米秸秆床上用品的需求, 许多生产者对可用于单坡设施的替代床上用品材料感兴趣。除了经济和动物的舒适性, 生产者还质疑床上用品材料将如何影响设施的环境, 包括恶臭气体的产生, 由此产生的肥料/寝具的营养成分, 以及病原体的存在。
很少有研究用于测量家畜住房中不同的床上用品材料所产生的空气质量, 大多数只集中在氨水上。以往对空气质量的评价大多包括在2、3、4、5对每种治疗进行一次或两个实验单位的农场数据收集。实验单位数量有限, 需要多次重复研究, 从而增加了诸如天气条件、动物生产年龄、产期等附加变量, 以及不同生长季节生产的床上用品材料。.
由于没有已知的实验室尺度模型来研究影响到牛肉深层单坡设施的肥料/床上用品混合物的空气质量和营养成分的因素, 研究人员首先试图利用商业牛设施深层系统6,7,8。在18月的6期间, 用静态通量室测量了单坡深层牛设施表面的 NH3浓度。测量了两个谷仓的两支钢笔。切碎玉米秸秆是首选的床上用品材料, 但小麦秸秆和大豆秸秆也用于床上用品在这个项目的短暂时期。床上用品的使用范围从每只动物每天 1.95-3.37 公斤不等, 笔密度从每只动物的 3.22-6.13 米2不等。随后的研究测量了谷仓7的氨和硫化氢排放量, 以及谷仓外的微粒物质浓度8。这些研究是在2年期间使用了四个谷仓地点进行的。农场数据收集面临的挑战是研究对系统缺乏控制。生产者改变牛的饮食, 把动物从钢笔转移到钢笔, 使用不同来源的床上用品, 清洁和重新床笔, 因为他们的生产和劳动力允许, 从而混淆了许多变数。农场的研究还涉及旅行费用和大量的实验性治疗 (如床上用品材料)。该项目的目的是建立一个实验室规模模型, 可用于研究影响到牛深层单坡设施的空气质量和营养管理的因素。

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		<tr>
			<td>10 gallon plastic cylinder containers</td>
			<td>Rubbermaid</td>
			<td>Model 2610</td>
			<td>Other similar-sized plastic containers are suitable</td>
		</tr>
		<tr>
			<td>Mass balance</td>
			<td>Any</td>
			<td></td>
			<td>Capable of measuring 0.1 gram</td>
		</tr>
		<tr>
			<td>Electric drill with 1 cm bit</td>
			<td>Any</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Methane analyzer</td>
			<td>Thermo Fisher Scientific</td>
			<td>Model 55i Methane/Non-methane Analyzer</td>
			<td></td>
		</tr>
		<tr>
			<td>Hydrogen sulfide analyzer</td>
			<td>Thermo Fisher Scientific</td>
			<td>Model 450i</td>
			<td></td>
		</tr>
		<tr>
			<td>Ammonia analyzer</td>
			<td>Thermo Fisher Scientific</td>
			<td>Model 17i</td>
			<td></td>
		</tr>
		<tr>
			<td>Carbon dioxide analyzer</td>
			<td>California Analytical</td>
			<td>Model 1412</td>
			<td></td>
		</tr>
		<tr>
			<td>Nitrous oxide analyzer</td>
			<td>California Analytical</td>
			<td>Model 1412</td>
			<td></td>
		</tr>
		<tr>
			<td>Programmable Logic Relay</td>
			<td>TECO</td>
			<td>Model SG2-020VR-D</td>
			<td></td>
		</tr>
		<tr>
			<td>Stainless steel flux chambers</td>
			<td>Any</td>
			<td></td>
			<td>Constructed using the parts list and directions cited at Woodbury et al., 2006</td>
		</tr>
		<tr>
			<td>Rubber skits</td>
			<td>Any</td>
			<td></td>
			<td>Constructed from flexible rubber material. Cut into squares (61 cm x 61 cm) with 22.9 cm diameter hole in center.&#160;</td>
		</tr>
		<tr>
			<td>pH meter</td>
			<td>Spectrum Technologies</td>
			<td>IQ150</td>
			<td></td>
		</tr>
		<tr>
			<td>thermometer</td>
			<td>Spectrum Technologies</td>
			<td>IQ150</td>
			<td></td>
		</tr>
		<tr>
			<td>Ruler or tape measure</td>
			<td>Any</td>
			<td></td>
			<td>Capable of measuring in cm</td>
		</tr>
		<tr>
			<td>Sorbent tubes</td>
			<td>Markes International</td>
			<td>Tenax TA</td>
			<td></td>
		</tr>
		<tr>
			<td>Pocket pumps</td>
			<td>SKC Inc.</td>
			<td>Series 210</td>
			<td></td>
		</tr>
		<tr>
			<td>Inert sampling line</td>
			<td>Teflon</td>
			<td></td>
			<td>0.64 cm diameter</td>
		</tr>
		<tr>
			<td>Pump</td>
			<td>Thomas</td>
			<td>107 series</td>
			<td>Used to flush air through sample lines</td>
		</tr>
	</tbody>
</table>

lab-scale model to evaluate odor and gas concentrations emitted by deep bedded pack manure

为了研究牛单坡设施中深层包层的空气质量和营养成分, 建立了实验室规模的模拟层包模型。该协议已被用来有效地评估许多不同的床上用品材料, 环境变量 (温度, 湿度) 和潜在的缓解措施, 可以改善空气质量的商业深层单坡设施。该模型是动态的, 让研究人员可以很容易地收集许多化学和物理测量的层状包。每周测量, 收集在六至七周的过程中, 可以有足够的时间看到空气质量测量随着时间的推移, 随着层状包装的成熟。从模拟的层状包收集的数据是在以前测量的商业深层单坡设施的浓度范围内。过去的研究表明, 每项治疗的 8-10 实验单位都足以发现模拟的层状包之间的统计差异。这些层状的包很容易维护, 每层包每周需要少于10分钟的人工添加尿液、粪便和寝具。根据收集的测量结果, 使用气体取样系统采集样品需要每层包 20-30 分钟。利用实验室规模的层状包, 研究者可以控制在研究或商业设施中难以或不可能控制的温度、湿度和床上用品来源等变量。虽然不是一个完美的模拟 "真实世界" 的条件, 模拟的层状包作为一个良好的模型, 研究人员用来检查治疗差异的包间。一些实验室规模的研究可以进行, 以消除可能的治疗之前, 尝试在研究或商业规模的设施。

到目前为止, 已有七项研究报告发表在9、10、11、12、13、14、15 、使用本程序, 并进行了修改和调整以改进模型和反映具体实验的目标。该程序已被用来评估许多床上用品材料和环境温度对气味和气体生产的影响, 以及可以增加控制氨排放的修正。在商业谷仓6、28以及模拟层包 (表 1) 中测量了层状包的化学和物理性能。这些数据用于确定该议定书是否适合用于补充昂贵的农场研究试验。空气质量数据已从商业设施和模拟层包收集使用两种不同的方法 (表 2)。本协议中描述的气体采样系统是一种新的技术, 已经过测试, 并与以前使用过的方法进行了比较。
模拟层状包的干物质组成在6、28的商业设施中所收集的层状包装材料的干物质含量范围内。第一次使用该协议11, 400 克的床上用品最初添加到层状包装, 随后增加200克每周的新鲜床上用品, 400 克每尿和粪便增加三次每周。这是为了模拟商业谷仓, 其中最初添加了多包床上用品, 并在此后每周只添加一到两包包。床上用品的比率: 家畜废物估计使用从商业深层状的单斜坡设施收集的数据1,6。在第一项研究结束时, 层状包的干物质含量类似于从商业设施6、28收集的层状包装材料中测量的干物质含量。然而, 对层状包装物的目视观察表明, 床上用品材料的持水能力存在很大的变异性。例如, 带有玉米棒子的层状包看起来很湿, 但干物质含量为 27.2, 1.5%16, 而与麦草被褥的层状包似乎相对干燥, 但有一个干物质含量 21.2 @ 1.1%11。为了更好地代表商业谷仓6,28, 试图增加层状包的干物质含量, 该协议的调整略有320克, 每个床上用品, 尿和粪便添加时, 包开始, 三每周增加320克每尿和粪便, 每周增加320克的床上用品材料添加到包装。该协议提高了层状包的干物质含量, 但高度依赖于试验中使用的床上用品材料13和环境分庭14的温度。虽然它是可变的, 模拟的层状包的干物质含量在商业谷仓测量的范围之内, 因此第二个协议为所有以后的研究使用了。
模拟层包的营养成分、包装温度和 pH 值进一步证明, 模拟层状包是在商业设施中代表粪便包层的良好模型。总氮, 总磷, 总硫, 总钾一直是从商业深层单斜坡设施6,28测量的养分含量范围内。部分堆肥发生在深层单坡设施的层状包装上, 因此在实验室规模的模拟层包中复制商业设施的温度是很重要的。深层商业设施中的层状包装温度, 当环境气温介于0和20.6 之间时, ˚C 为 19.2, 0.3 ˚C 6。在使用本议定书进行的大多数研究中, 环境室的温度设置为20˚C。在这些研究中, 模拟层状包的温度一直保持在18.3 和20.1 ˚C 之间。例外的是, 当温度是一个因素, 测试了三路阶乘实验。两个环境室设在40˚C, 两个设在10˚C。在这项研究中, 模拟的层状包的温度是 12-13 ˚C 在冷室和 32-35 ˚C 在温暖的房间。再次, 这反映了商业谷仓, 其中包装温度是 15.4, 0.4 ˚C, 当环境温度是0˚C 或更冷, 29.0 @ 0.3 ˚C 当环境空气温度大于20.6 ˚C 6。用玉米秸秆寝具对商业粮仓中的层状包进行了 pH 值测定, 其中一项研究6 , 从 7.5-8.0 不等。模拟层包与玉米秸秆床上用品有 pH 值 7.1-7.311,13。所有模拟层状包的 pH 值从6.2 到9.0 不等, 这反映了实验中使用的各种床上用品材料。
本议定书所使用的气体取样系统是根据29国家空气排放监测研究的一部分, 在商业家禽、猪和奶牛场进行的一系列研究中加以调整的。该系统通过通量室冲洗室内空气, 创建一个动态通量室, 用于测量20分钟内排放的选定气体的浓度。在使用气体取样系统之前, 通过使用含有2摩尔 L-1硫酸6的酸阱的静态通量室从每个层状包中收集空气样本来确定 NH3的稳态浓度,22. 分庭内的空气通过酸性捕集器回收, 速度为1升-1 20 分钟。使用手持取样器收集了总还原硫化物。空气样品通过静态通量室循环使用一个小泵, 流速为1升分钟, 不超过4分钟。每个模拟层包中至少抽取四个连续样品。温室气体浓度 (N20、CO2和 CH4) 是通过在每个静态通量室顶部的间隔, 从每个模拟的层状包中收集一个20毫升的空气样本来确定的。随后用气相色谱仪对样品进行了分析。以前收集这些气体样本的方法是非常劳力密集型的, 需要三人管理所有的收集设备。气体取样系统的使用要少得多的劳动密集型。一个人可以建立气体取样系统, 启动可编程逻辑继电器和返回约160分钟后, 当样品已完成收集气体数据从8模拟层包。
从以前的劳动密集型取样协议中得到的结果, 以及气体取样系统的结果 (表 2)。由于收集数据所需的劳动量, 并非所有数据都能从商业设施中收集。采用酸性捕集法从商用单坡设施的层状包装表面收集氨浓度, 并与模拟层包进行比较。在模拟的层状包中测定的氨浓度与商业牛设施中的层状包所测量的 NH3浓度一致。使用新的气体取样系统的氨浓度似乎是在牛的设施集中的低端。这可能是由 NH3分析仪引起的, 也可能是使用新的气体取样系统的实验中的处理方法的反映。它还能反映出比商业谷仓的气流更高的模拟层包空气流量, 这将稀释氨样品的浓度。一系列的实验测试了使用明矾作为表面修正, 可以应用于层状包装, 以降低包装 pH 值, 从而减少氮挥发的 NH3。在商业设施的层状包装表面没有测量二氧化碳、CH4和 N2O。然而, 使用以前的气相色谱法测定的模拟层状包中这些气体的浓度范围和使用气体取样系统测量的浓度范围非常相似。当模拟的层状包放置在35˚C 环境室中时, 相对于20˚C 室, 产生了较高浓度, 这说明了实验中的变异性。将其与硫化氢进行比较并不是直接的比较, 因为它不仅包括硫化氢。因此, 模拟层包的 H2S 浓度略高于使用气体取样系统测量的含量, 这一点不足为奇。这也反映了使用这两种取样协议进行的研究。包含绿色雪松床上用品的层状包装产生了非常高的12的的, 而那些含有玉米秸秆床上用品的人则没有。采用气体取样系统采集的样品, 采用玉米秸秆、麦草、大豆秸秆、松片床上用品等材料, 但无绿色雪松床上用品。
<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always"><tbody>
<tr>
<td></td>
			<td colspan="2">商业谷仓1-2</td>
			<td colspan="4">模拟层包3-6</td>
		</tr>
<tr>
<td>干物质,%</td>
			<td>29.99 @ 3.15</td>
			<td>16.0 至36。6</td>
			<td>20.8 至27。2</td>
			<td>22.3 至26。1</td>
			<td>24.0 至58。0</td>
			<td>20.8 至24。9</td>
		</tr>
<tr>
<td>总 N, g 公斤-1</td>
			<td>60.97 @ 13.77</td>
			<td>21.2 至23。6</td>
			<td>19.4 至28。2</td>
			<td>17.8 至22。3</td>
			<td>15.6 至18。6</td>
			<td>17.8 至23。8</td>
		</tr>
<tr>
<td>总 P, g 公斤-1</td>
			<td>14.13 @ 3.99</td>
			<td>6.7 至7。5</td>
			<td>6.2 至9。6</td>
			<td>7.1 至9。6</td>
			<td>6.7 至8。5</td>
			<td>6.2 至9。6</td>
		</tr>
<tr>
<td>共计 S, g 公斤-1</td>
			<td>7.88 @ 1.48</td>
			<td>5.6 至6。7</td>
			<td>3.6 至6。5</td>
			<td>4.5 至5。3</td>
			<td>---</td>
			<td>3.6 至6。5</td>
		</tr>
<tr>
<td>总 K, g 公斤-1</td>
			<td>32.74 @ 8.39</td>
			<td>15.5 至21。1</td>
			<td>16.3 至23。1</td>
			<td>---</td>
			<td>18.8 至25。6</td>
			<td>16.3 至25。2</td>
		</tr>
<tr>
<td>木质素, g 公斤-1</td>
			<td>---</td>
			<td>---</td>
			<td>26.5 至139。6</td>
			<td>49.9 至136。9</td>
			<td>---</td>
			<td>62.6 至139。6</td>
		</tr>
<tr>
<td>灰, g 公斤-1</td>
			<td>---</td>
			<td>154-214</td>
			<td>119.3 至200。5</td>
			<td>98.9 至223。6</td>
			<td>---</td>
			<td>119.3 至200。5</td>
		</tr>
<tr>
<td>C: N 比率</td>
			<td>---</td>
			<td>---</td>
			<td>17.4 至28。2</td>
			<td>20.2 至29。7</td>
			<td>---</td>
			<td>20.6 至27。5</td>
		</tr>
<tr>
<td>Ph</td>
			<td>---</td>
			<td>7.5-8</td>
			<td>6.2 至7。2</td>
			<td>6.8 至7。6</td>
			<td>8.5 至9。0</td>
			<td>7.4 至7。7</td>
		</tr>
<tr>
<td>温度、˚C</td>
			<td>---</td>
			<td>15.4 至29。0</td>
			<td>18.3 至19。9</td>
			<td>18.4 至20。0</td>
			<td>12.0 至35。0</td>
			<td>19.7 至20。1</td>
		</tr>
<tr>
<td colspan="7">
1Euken, 2009。Euken 报告的标准偏差, 显示2009。用2o5和 k2o 组成分别转化为 p、总 k。</td>
		</tr>
<tr>
<td colspan="7">
2Spiehs 等, 2011。从两个谷仓中的两支钢笔收集的数据。切碎玉米秸秆是首选的床上用品材料, 但小麦秸秆和大豆秸秆也用于床上用品在这个项目的短暂时期。床上用品的使用范围从每只动物每天1.95 至3.37 公斤不等, 笔密度从每只动物的3.22 至 6.13 m2 不等。</td>
		</tr>
<tr>
<td colspan="7">
3Spiehs 等, 2012。从模拟层包收集的数据。床上用品材料包括玉米秸秆, 豆类秸秆, 麦草, 颗粒玉米棒子, 纸, 木片, 木屑。</td>
		</tr>
<tr>
<td colspan="7">
4Spiehs 等, 2014b。从模拟层包收集的数据。床上用品材料包括玉米秸秆, 松树木片, 湿雪松薯条, 干雪松薯条。</td>
		</tr>
<tr>
<td colspan="7">
5Ayadi 等, 2015b。用玉米秸秆和豆科秸秆材料收集的模拟层状包中的数据。使用了二个温度 (40˚C 和 10˚C)</td>
		</tr>
<tr>
<td colspan="7">
6Spiehs 等, 2017。使用含有0、10、20、30、40、60、80、100% 松树和剩余玉米秸秆的寝具材料混合而成的模拟层状包收集的数据。</td>
		</tr>
</tbody></table>表1。从商用深层单坡设施 (Euken、2009和 Spiehs 等)、2011) 和使用模拟的床包进行的研究中报告的干物质和营养成分 (干物质基础) 的范围 (Spiehs et2012, 2014, 2017 和 Ayadi 等, 2015)。
<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always"><tbody>
<tr>
<td></td>
			<td colspan="4">静磁通室法1</td>
			<td colspan="2">动态通量室法2</td>
		</tr>
<tr>
<td>氨, ppm</td>
			<td>95.8 至641。1</td>
			<td>350.8 至516。7</td>
			<td>381-1584</td>
			<td>386.3 至502。3</td>
			<td colspan="2">89.4 至166。7</td>
		</tr>
<tr>
<td>ppb</td>
			<td>---</td>
			<td>8.2 至165。9</td>
			<td>---</td>
			<td>5.3 至11。4</td>
			<td colspan="2">---</td>
		</tr>
<tr>
<td>硫化氢, ppb</td>
			<td>---</td>
			<td>---</td>
			<td>---</td>
			<td>---</td>
			<td colspan="2">0.1 至18。1</td>
		</tr>
<tr>
<td>二氧化碳, ppm</td>
			<td>---</td>
			<td>1232-2000</td>
			<td>2322-6917</td>
			<td>918-1158</td>
			<td colspan="2">957至2149</td>
		</tr>
<tr>
<td>甲烷、ppm</td>
			<td>---</td>
			<td>2.3 至3。6</td>
			<td>7.2 至87。0</td>
			<td>4.4 至6。7</td>
			<td colspan="2">3.2 至16。7</td>
		</tr>
<tr>
<td>一氧化二氮, ppm</td>
			<td>---</td>
			<td>0.67 至0.72</td>
			<td>0.31 至0.77</td>
			<td>0.21 至0.23</td>
			<td colspan="2">0.44 至0.58</td>
		</tr>
<tr>
<td colspan="7">
1Spiehs 等, 2011, 2014a, 2015a, 2016a。这些研究的数据是使用氨水的酸性陷阱收集的, 这是一只手持式总还原硫化物的取样器, 从每个模拟层包顶空的一个样品中分析了二氧化碳、甲烷和一氧化二氮的温室气体 GC。</td>
		</tr>
<tr>
<td colspan="7">
2这些数据代表了三项研究, 使用不同的床上用品材料和表面修正来控制气味和气体排放。这些研究是使用气体取样系统进行的, 尚未公布。</td>
		</tr>
</tbody></table>表2。从商用深层单坡设施 (Spiehs 等) 中报告的氨、总还原硫化物、硫化氢、二氧化碳、甲烷和一氧化二氮的报道范围 (2011) 和利用模拟的研究进行层状包 (Spiehs 等, 2014a, 2016 和 Ayadi 等, 2015)。
<img alt="Figure 1" class="xfigimg" src="/files/ftp_upload/57332/57332fig1.jpg"> 图1。在塑料容器中用不锈钢通量室和橡皮短剧模拟成层包, 并准备好进行空气取样.模拟的层状包位于环境室内。<a href="/files/ftp_upload/57332/57332fig1large.jpg" target="_blank">请单击此处查看此图的较大版本.</a>

Watch this Scientific Journal Video about Lab-Scale Model to Evaluate Odor and Gas Concentrations Emitted by Deep Bedded Pack Manure at JoVE.com

Lab-Scale Model to Evaluate Odor and Gas Concentrations Emitted by Deep Bedded Pack Manure

用实验室尺度模型评价深层包粪排放的恶臭和气体浓度

制定了一项议定书, 用于测量实验室规模的粪便包中的气体、气味和营养成分, 可用于研究利用深层粪袋改善商业牲畜设施空气质量的方法。

A lab-scaled simulated bedded pack model was developed to study air quality and nutrient composition of deep-bedded packs used in cattle mono-slope ...

lab-scale-model-to-evaluate-odor-gas-concentrations-emitted-deep

Nanyang Technological University

Research

JoVE Journal

Environment

6.3K 次观看.  USDA ARS U.S. Meat Animal Research Center. 制定了一项议定书, 用于测量实验室规模的粪便包中的气体、气味和营养成分, 可用于研究利用深层粪袋改善商业牲畜设施空气质量的方法。

视频: Lab-Scale Model to Evaluate Odor and Gas Concentrations Emitted by Deep Bedded Pack Manure

Optimize Flue Gas Settings to Promote Microalgae Growth in Photobioreactors via Computer Simulations

Flue gas from power plants can promote algal cultivation and reduce greenhouse gas emissions1. Microalgae not only capture solar energy more efficiently than plants3, but also synthesize advanced biofuels2-4. Generally, atmospheric CO2 is not a sufficient source for supporting maximal algal growth5. On the other hand, the high concentrations of CO2 in industrial exhaust gases have adverse effects on algal physiology. Consequently, both cultivation conditions (such as nutrients and light) and the control of the flue gas flow into the photo-bioreactors are important to develop an efficient &ldquo;flue gas to algae&rdquo; system. Researchers have proposed different photobioreactor configurations4,6 and cultivation strategies7,8 with flue gas. Here, we present a protocol that demonstrates how to use models to predict the microalgal growth in response to flue gas settings. We perform both experimental illustration and model simulations to determine the favorable conditions for algal growth with flue gas. We develop a Monod-based model coupled with mass transfer and light intensity equations to simulate the microalgal growth in a homogenous photo-bioreactor. The model simulation compares algal growth and flue gas consumptions under different flue-gas settings. The model illustrates: 1) how algal growth is influenced by different volumetric mass transfer coefficients of CO2; 2) how we can find optimal CO2 concentration for algal growth via the dynamic optimization approach (DOA); 3) how we can design a rectangular on-off flue gas pulse to promote algal biomass growth and to reduce the usage of flue gas. On the experimental side, we present a protocol for growing Chlorella under the flue gas (generated by natural gas combustion). The experimental results qualitatively validate the model predictions that the high frequency flue gas pulses can significantly improve algal cultivation.

Flue gas from power plants is a cheap CO2 source for algal growth. We have built prototype &#34;flue gas to algal cultivation&#34; systems and described how to scale up the algal cultivation process. We have demonstrated the use of a mass-transfer bio-reaction model to simulate and to design the optimal operation of flue gas for the growth of Chlorella sp. in algal photo-bioreactors.

优化烟气设置通过电脑模拟来促进微藻生长的光生物反应器中

Flue gas from power plants can promote algal cultivation and reduce greenhouse gas emissions1. Microalgae not only capture solar energy more efficiently ...

科研

环境科学

Measurement of Greenhouse Gas Flux from Agricultural Soils Using Static Chambers

Measurement of greenhouse gas (GHG) fluxes between the soil and the atmosphere, in both managed and unmanaged ecosystems, is critical to understanding the biogeochemical drivers of climate change and to the development and evaluation of GHG mitigation strategies based on modulation of landscape management practices. The static chamber-based method described here is based on trapping gases emitted from the soil surface within a chamber and collecting samples from the chamber headspace at regular intervals for analysis by gas chromatography. Change in gas concentration over time is used to calculate flux. This method can be utilized to measure landscape-based flux of carbon dioxide, nitrous oxide, and methane, and to estimate differences between treatments or explore system dynamics over seasons or years. Infrastructure requirements are modest, but a comprehensive experimental design is essential. This method is easily deployed in the field, conforms to established guidelines, and produces data suitable to large-scale GHG emissions studies.

This article showcases the static chamber-based method for measurement of greenhouse gas flux from soil systems. With relatively modest infrastructure investments, measurements may be obtained from multiple treatments/locations and over timeframes ranging from hours to years.

从农业土壤使用静态钱伯斯温室气体流量测量

Measurement of greenhouse gas (GHG) fluxes between the soil and the atmosphere, in both managed and unmanaged ecosystems, is critical to understanding the ...

Measurement of H2S in Crude Oil and Crude Oil Headspace Using Multidimensional Gas Chromatography, Deans Switching and Sulfur-selective Detection

A method for the analysis of dissolved hydrogen sulfide in crude oil samples is demonstrated using gas chromatography. In order to effectively eliminate interferences, a two dimensional column configuration is used, with a Deans switch employed to transfer hydrogen sulfide from the first to the second column (heart-cutting). Liquid crude samples are first separated on a dimethylpolysiloxane column, and light gases are heart-cut and further separated on a bonded porous layer open tubular (PLOT) column that is able to separate hydrogen sulfide from other light sulfur species. Hydrogen sulfide is then detected with a sulfur chemiluminescence detector, adding an additional layer of selectivity. Following separation and detection of hydrogen sulfide, the system is backflushed to remove the high-boiling hydrocarbons present in the crude samples and to preserve chromatographic integrity. Dissolved hydrogen sulfide has been quantified in liquid samples from 1.1 to 500 ppm, demonstrating wide applicability to a range of samples. The method has also been successfully applied for the analysis of gas samples from crude oil headspace and process gas bags, with measurement from 0.7 to 9,700 ppm hydrogen sulfide.

Measurement of H2S in Crude Oil and Crude Oil Headspace Using Multidimensional Gas Chromatography, Deans Switching and Sulfur-selective Detection

A multidimensional gas chromatography method for the analysis of dissolved hydrogen sulfide in liquid crude oil samples is presented. A Deans switch is used to heart-cut light sulfur gases for separation on a secondary column and detection on a sulfur chemiluminescence detector.

h的测量<sub&gt; 2</sub&gt; S在原油和原油顶空用多维气相色谱法，院长交换和选择性硫检测

A method for the analysis of dissolved hydrogen sulfide in crude oil samples is demonstrated using gas chromatography. In order to effectively eliminate ...

A Push-pull Protocol to Reduce Colonization of Bird Nest Boxes by Honey Bees

Introduction of the invasive Africanized honey bee (AHB) into the Neotropics is a serious problem for many cavity nesting birds, specifically parrots. These bees select cavities that are suitable nest sites for birds, resulting in competition. The difficulty of removing bees and their defensive behavior makes a prevention protocol necessary. Here, we describe a push-pull integrated pest management protocol to deter bees from inhabiting bird boxes by applying a bird safe insecticide, permethrin, to repel bees from nest boxes, while simultaneously attracting them to pheromone-baited swarm traps. Shown here is an example experiment using Barn Owl nest boxes. This protocol successfully reduced colonization of Barn Owl nest boxes by Africanized honey bees. This protocol is flexible, allowing adjustments to accommodate a wide range of bird species and habitats. This protocol could benefit conservation efforts where AHB are located.

Preventing colonization of bird nest boxes by invasive Africanized honey bees is important for conservation efforts of nest-site limited birds. We provide an integrated pest management approach to &#34;push&#34; bees away from nest boxes with a repellant insecticide, permethrin, and &#34;pull&#34; them toward pheromone baited swarm traps.

推挽议定书蜜蜂会影响家禽的殖民化巢箱

Introduction of the invasive Africanized honey bee (AHB) into the Neotropics is a serious problem for many cavity nesting birds, specifically parrots. ...

Protocol for Measuring the Thermal Properties of a Supercooled Synthetic Sand-water-gas-methane Hydrate Sample

Methane hydrates (MHs) are present in large amounts in the ocean floor and permafrost regions. Methane and hydrogen hydrates are being studied as future energy resources and energy storage media. To develop a method for gas production from natural MH-bearing sediments and hydrate-based technologies, it is imperative to understand the thermal properties of gas hydrates.
The thermal properties' measurements of samples comprising sand, water, methane, and MH are difficult because the melting heat of MH may affect the measurements. To solve this problem, we performed thermal properties' measurements at supercooled conditions during MH formation. The measurement protocol, calculation method of the saturation change, and tips for thermal constants' analysis of the sample using transient plane source techniques are described here.
The effect of the formation heat of MH on measurement is very small because the gas hydrate formation rate is very slow. This measurement method can be applied to the thermal properties of the gas hydrate-water-guest gas system, which contains hydrogen, CO2, and ozone hydrates, because the characteristic low formation rate of gas hydrate is not unique to MH. The key point of this method is the low rate of phase transition of the target material. Hence, this method may be applied to other materials having low phase-transition rates.

We present a protocol for measuring the thermal properties of synthetic hydrate-bearing sediment samples comprising sand, water, methane, and methane hydrate.

协议测量过冷的合成砂水 - 气 - 甲烷水合物样品的热性能

Methane hydrates (MHs) are present in large amounts in the ocean floor and permafrost regions. Methane and hydrogen hydrates are being studied as future ...

Methods of Soil Resampling to Monitor Changes in the Chemical Concentrations of Forest Soils

Recent soils research has shown that important chemical soil characteristics can change in less than a decade, often the result of broad environmental changes. Repeated sampling to monitor these changes in forest soils is a relatively new practice that is not well documented in the literature and has only recently been broadly embraced by the scientific community. The objective of this protocol is therefore to synthesize the latest information on methods of soil resampling in a format that can be used to design and implement a soil monitoring program. Successful monitoring of forest soils requires that a study unit be defined within an area of forested land that can be characterized with replicate sampling locations. A resampling interval of 5 years is recommended, but if monitoring is done to evaluate a specific environmental driver, the rate of change expected in that driver should be taken into consideration. Here, we show that the sampling of the profile can be done by horizon where boundaries can be clearly identified and horizons are sufficiently thick to remove soil without contamination from horizons above or below. Otherwise, sampling can be done by depth interval. Archiving of sample for future reanalysis is a key step in avoiding analytical bias and providing the opportunity for additional analyses as new questions arise.

Repeated soil sampling has recently been shown to be an effective way to monitor forest soil change over years and decades. To support its use, a protocol is presented that synthesizes the latest information on soil resampling methods to aid in the design and implementation of successful soil monitoring programs.

土壤重采样的方法监控森林土壤的化学浓度的变化

Recent soils research has shown that important chemical soil characteristics can change in less than a decade, often the result of broad environmental ...

Ecotoxicological Method with Marine Bacteria Vibrio anguillarum to Evaluate the Acute Toxicity of Environmental Contaminants

Bacteria are an important component of the ecosystem, and microbial community alterations can have a significant effect on biogeochemical cycling and food webs. Toxicity testing based on microorganisms are widely used because they are relatively quick, reproducible, cheap, and are not associated with ethical issues. Here, we describe an ecotoxicological method to evaluate the biological response of the marine bacterium Vibrio anguillarum. This method assesses the acute toxicity of chemical compounds, including new contaminants such as nanoparticles, as well as environmental samples. The endpoint is the reduction of bacterial culturability (i.e., the capability to replicate and form colonies) due to exposure to a toxicant. This reduction can be generally referred to as mortality. The test allows for the determination of the LC50, the concentration that causes a 50% decrease of bacteria actively replicating and forming colonies, after a 6 h exposure. The culturable bacteria are counted in terms of colony forming units (CFU), and the &#34;mortality&#34; is evaluated and compared to the control. In this work, the toxicity of copper sulphate (CuSO4) was evaluated. A clear dose-response relationship was observed, with a mean LC50 of 1.13 mg/L, after three independent tests. This protocol, compared to existing methods with microorganisms, is applicable in a wider range of salinity and has no limitations for colored/turbid samples. It uses saline solution as the exposure medium, avoiding any possible interferences of growth medium with the investigated contaminants. The LC50 calculation facilitates comparisons with other bioassays commonly applied to ecotoxicological assessments of the marine environment.

Ecotoxicological Method with Marine Bacteria Vibrio anguillarum to Evaluate the Acute Toxicity of Environmental Contaminants

This work describes a new protocol to assess the ecotoxicity of pollutants, including emerging contaminants such as nanomaterials, using the marine bacterium Vibrio anguillarum. This method allows for the determination of the LC50, or mortality, the concentration that causes a 50% decrease in bacteria culturability, after a 6 h exposure.

生物毒理学方法与海洋细菌<em&gt;鳗弧菌</em&gt;评估环境污染物的急性毒性

Bacteria are an important component of the ecosystem, and microbial community alterations can have a significant effect on biogeochemical cycling and food ...

Measuring and Mapping Patterns of Soil Erosion and Deposition Related to Soil Carbonate Concentrations Under Agricultural Management

Spatial patterns of soil erosion and deposition can be inferred from differences in ground elevation mapped at appropriate time increments. Such changes in elevation are related to changes in near-surface soil carbonate (CaCO3) profiles. The objective is to describe a simple conceptual model and detailed protocol for repeatable field and laboratory measurements of these quantities. Here, accurate elevation is measured using a ground-based differential global positioning system (GPS); other data acquisition methods could be applied to the same basic method. Soil samples are collected from prescribed depth intervals and analyzed in the lab using an efficient and precise modified pressure-calcimeter method for quantitative analysis of inorganic carbon concentration. Standard statistical methods are applied to point data, and representative results show significant correlations between changes in soil surface layer CaCO3 and changes in elevation consistent with the conceptual model; CaCO3 generally decreased in depositional areas and increased in erosional areas. Maps are derived from point measurements of elevation and soil CaCO3 to aid analyses. A map of erosional and depositional patterns at the study site, a rain-fed winter wheat field cropped in alternating wheat-fallow strips, shows the interacting effects of water and wind erosion affected by management and topography. Alternative sampling methods and depth intervals are discussed and recommended for future work relating soil erosion and deposition to soil CaCO3.

Spatial patterns of soil erosion and deposition can be inferred from differences in ground elevation mapped at appropriate time increments. Such changes in elevation are related to changes in near-surface soil carbonates. Repeatable methods for field and laboratory measurements of these quantities and data analysis methods are described here.

农业经营条件下土壤侵蚀和沉积与土壤碳酸盐浓度关系的测量与制图

Spatial patterns of soil erosion and deposition can be inferred from differences in ground elevation mapped at appropriate time increments. Such changes ...

Operation of a 25 KWth Calcium Looping Pilot-plant with High Oxygen Concentrations in the Calciner

Calcium looping (CaL) is a post-combustion CO2 capture technology that is suitable for retrofitting existing power plants. The CaL process uses limestone as a cheap and readily available CO2 sorbent. While the technology has been widely studied, there are a few available options that could be applied to make it more economically viable. One of these is to increase the oxygen concentration in the calciner to reduce or eliminate the amount of recycled gas (CO2, H2O and impurities); therefore, decreasing or removing the energy necessary to heat the recycled gas stream. Moreover, there is a resulting increase in the energy input due to the change in the combustion intensity; this energy is used to enable the endothermic calcination reaction to occur in the absence of recycled flue gases. This paper presents the operation and first results of a CaL pilot plant with 100% oxygen combustion of natural gas in the calciner. The gas coming into the carbonator was a simulated flue gas from a coal-fired power plant or cement industry. Several limestone particle size distributions are also tested to further explore the effect of this parameter on the overall performance of this operating mode. The configuration of the reactor system, the operating procedures, and the results are described in detail in this paper. The reactor showed good hydrodynamic stability and stable CO2 capture, with capture efficiencies of up to 70% with a gas mixture simulating the flue gas of a coal-fired power plant.

Operation of a 25 KWth Calcium Looping Pilot-plant with High Oxygen Concentrations in the Calciner

This manuscript describes a procedure for operating a calcium looping pilot-plant for post-combustion carbon capture with high oxygen concentrations in the calciner in order to reduce or eliminate the flue gas recycle.

在煅烧炉中使用高氧浓度的 25 KWth钙循环试验装置的操作

Calcium looping (CaL) is a post-combustion CO2 capture technology that is suitable for retrofitting existing power plants. The CaL process uses limestone ...

Procedures of Laboratory Fumigation for Pest Control with Nitric Oxide Gas

Nitric oxide (NO) is a newly discovered fumigant for postharvest pest control. This paper provides detailed protocols for conducting NO fumigation on fresh products and procedures for residue analysis and product quality evaluation. An airtight fumigation chamber containing fresh fruit and vegetables is first flushed with nitrogen (N2) to establish an ultralow oxygen (ULO) environment followed by injection of NO. The fumigation chamber is then kept at a low temperature of 2 - 5 &#176;C for a specified time period necessary to kill a target pest to complete a fumigation treatment. At the end of a fumigation treatment, the fumigation chamber is flushed with N2 to dilute NO prior to opening the chamber to ambient air to prevent the reaction between NO and O2, which produces NO2 and may damage delicate fresh products. At different times after NO fumigation, NO2 in headspace and nitrate and nitrite in liquid samples were measured as residues. Product quality was evaluated after 2 weeks of post-treatment cold storage to determine effects of NO fumigation on product quality. Keeping&#160;O2 from reacting with NO is critical to NO fumigation and is an important part of the protocols. Measuring NO levels is challenging and a practical solution is provided. Possible protocol modifications are also suggested for measuring NO levels in the fumigation chambers as well as residues. NO fumigation has the potential to be a practical alternative to methyl bromide fumigation for postharvest pest control on fresh and stored products. This publication is intended to assist other researchers in conducting NO fumigation research for postharvest pest control and accelerating the development of NO fumigation for practical applications.

This paper describes nitric oxide (NO) fumigation protocols for postharvest pest control. Fumigation chambers are flushed with nitrogen (N2) to establish ultralow oxygen conditions before NO is injected. At the end, chambers are flushed with N2 to dilute NO before exposing products to ambient air to prevent exposure to NO2.

一氧化氮气体防治害虫实验室熏蒸程序

Nitric oxide (NO) is a newly discovered fumigant for postharvest pest control. This paper provides detailed protocols for conducting NO fumigation on ...