这项研究是由美国国家科学基金会的程序（研究经验的本科生）在华盛顿大学圣路易斯分校的支持。

1。海藻栽培和规模化发展<ol><li>使用去离子水含有0.55克/ L -1尿素，0.1185克/ L -1 KH 2 PO 4，0.102克/ L -1的用MgSO 4·7H 2 O 0.015克/升-1的FeSO 4·7H制备的培养基2 O和22.5微升微量元素（18.5克/升-1 H 3 BO 3，21.0克/升-1的CuSO 4·5H 2 O 73.2克/升-1的MnCl 2·4H 2 O，13.7克/升-1 COSO 4·7H 2 O 59.5克/升-1硫酸锌4·5H 2 O，3.8克/升-1（NH 4）6莫7 O 24·4H 2 O 0.31克/升-1 NH 4 VO 3 ）。调节介质pH值至7-8。通过0.22微米注射器过滤灭菌的培养基。 </li><li>接种小球藻 。从新鲜琼脂平板成一摇FLA单个菌落含有SK 50毫升培养基，用无菌接种环。在150转，30℃六天文化藻（连续光条件下，光子通量= 40-50微摩尔米-2秒-1）。用分光光度计（OD 730）监测细胞密度。 </li><li>转移50毫升藻培养物（中间数生长期，OD 730&gt; 1）到一个2升玻璃烧瓶（带有〜1升消毒培养液）。孵化（5天）在泵过滤空气（或CO 2）进入文化。 </li><li>转让1升藻培养到含有15升非灭菌的培养基（在这一阶段，微生物污染的危险性小），然后培养藻类相同的条件下，如步骤1.3中所述的可20-L玻璃大玻璃瓶。 </li><li>放置15升新鲜藻类培养物（OD 730 = 2）和85升非无菌培养基为平板光生物反应器（配有发光二极管，计算机控制器，气体混合物分析仪对细胞的光密度，pH值，溶解的氧根，温度和溶解的CO 2）。泵的烟气/空气混合物进入生物反应器。 </li><li>彻底干燥清洁，用70％乙醇的生物质收获后（外径730&gt; 20）的光生物反应器。 </li></ol> 2。烟气处理的使用小光生物反应器示范实验室<ol><li>接种在玻璃瓶中的藻类培养物（200毫升/分钟介质/瓶，初始OD 730〜0.3）。 </li><li>烧天然气和通过漏斗，冷凝管以及0.5升洗涤瓶（含有水/石灰石浆）泵烟气（约250 立方厘米每分钟）。 </li><li>质量流量控制器控制所述烟道气流进入藻类培养物（ 图1）。 烟道气体脉冲包括两种模式:烟气通和烟气销（空气泵代替）。 </li></ol> 3。动力学模型开发该动力学模型假设:（1）文化是均相体系秒。 （2）CO 2浓度和光照强度的文化是限制因素藻类生长。 （3） 二氧化碳分压和液相平衡与H 2 CO 3，HCO 3 -和CO 3 2 -简化与亨利定律）。该模型方程为: <img alt="方程1和2" fo:content-width="4in" src="/files/ftp_upload/50718/50718eq1and2.jpg" width="500px" /> X是生物量（千克·米-3）。 S是溶解的CO 2（摩尔·米-3）。 P是在气相中进行（Pa）的CO 2的分压。 P I是第 i 个有毒化合物的气体（如NO x和 SO x）的中的分压。 P max.i是有毒的气体的分压来对生物生长充分抑制。 ηi是经验系数。 K表s是米氏常数CO 2（摩尔·米-3）。 K I是CO 2的抑制常数（摩尔·米-3）。 K为光强度的米氏常数（微摩尔·米-2·秒-1）。 H为亨利常数的CO 2（帕·米3·摩尔-1）。 ķLa为CO 2（小时-1）的传质速率。 I是平均光强，微摩尔·米-2·秒-1，它可以如下9来计算（（3）公式）。 <img alt="式（3）" fo:content-width="4in" src="/files/ftp_upload/50718/50718eq3.jpg" width="500px" />模型参数的定义是在表1中 。初始条件假定生物质和溶解的CO 2的浓度是100 mg / L和13μmol/ L的分别。的体积传质系数可以通过经验关系来估计tion到生物反应器参数10: <img alt="公式4" fo:content-width="4in" src="/files/ftp_upload/50718/50718eq4.jpg" width="500px" /> 全干/ V是加气系统在生物反应器的功耗（瓦/米3）。 üGS是气流的空塔速度通过所述生物反应器（米/秒）。 α，β，γ是与混合条件的常数。 <ol><li>构建一个Simulink的文件模型仿真（屏幕截图在辅助材料我给出）。 <ol><li>选择文件/新建/模型在MATLAB的接口来创建一个Simulink模型，并打开"库浏览器"（屏幕截图1）。 </li><li>选择库中的浏览器的子系统"块以创建子系统为等式1和2。拖动一个子系统块到Simulink的模型文件，其名称更改为"公式1"，然后重复同样的步骤进行公式2。 </li><lI&gt;在创建每个子系统适当的块和参数（屏幕截图3）。双击"公式1"块，从库浏览器中选择适当的块，用箭头表示的计算顺序，将它们连接双击块来设置参数，并为其他子系统重复这些步骤。 注:1）顺序应该从输入块和结束与输​​出块; 2）操作块加法，减法，乘法，除法和整合，可以在库浏览器找到的所有，我们建议用户探索的帮助文件在Simulink来了解如何使用它们; 3）优化求解器可以通过工具栏上的路径​​模拟/配置参数进行设置。 </li><li>连接两个子系统来表示模型方程（1和2）。如果需要一个子系统的输出连接到其它子系统的输入箭头。例如，溶解的CO 2浓度为邻安输出的方程2中的子系统，也是式（1）子系统的输入。 </li><li>使用"脉冲发生器"块作为输入，"公式2"，模拟开关CO 2脉冲;使用&#39;恒&#39;块作为表面光输入值。双击块来改变参数，如周期时间和幅度。 </li><li>选择"复用"在库浏览器的块。连接所有的输出为"复用"，然后将其连接到"要工作区"，用来存储模拟结果块。 </li><li>定义顶部工具栏上的"仿真停止时间"，点击按钮" <img src="/files/ftp_upload/50718/playarrow.jpg" alt="箭头" width="10px" fo:content-width="0.1in" fo:src="/files/ftp_upload/50718/playarrow.jpg" /> "开始模拟，其结果将在MATLAB工作区显示出来（屏幕截图4）。 </li></ol></li><li>应用动态优化的方法来分析最佳的CO 2的条件。 </LI&gt; </ol>找到入口流入的CO 2档（P OPT），最大限度地提高生物量生产11，MATLAB的fmincon&#39;函数和CVP（控制向量参数）12的使用变化。 图2说明了优化算法（见MATLAB编程代码中的支持材料II）。

<ol>
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这些作者都没有透露。

在这项研究中，我们证明了实验方案来扩大栽培藻类光生物反应器中。我们还考察了几种烟气投入，以促进藻类生长。利用传质和生物反应模型，我们表明，CO 2传质系数K 香格里拉 （由生物反应器混合条件和CO 2表观速度决定）强烈地影响着藻类生长。该模型模拟结果表明连续的通断烟气脉冲短脉冲宽度和高开关频率可以提高小球藻生长（ 即高频开关烟道气?...

<table border="0" cellpadding="0" cellspacing="0" width="636">
	<tbody>
		<tr height="21"> 
			<td height="21" style="height:21px;width:212px;">Spectrophotometer</td>
			<td style="width:212px;">Thermal Scientific, Texas USA</td>
			<td style="width:212px;"> </td>
		</tr>
		<tr height="39">
			<td height="39" style="height:39px;width:212px;">CO2 gas analyzer</td>
			<td style="width:212px;">LI-COR, Biosciences, Nebraska USA</td>
			<td style="width:212px;"> </td>
		</tr>
		<tr height="39">
			<td height="39" style="height:39px;width:212px;">Mass flow controllers</td>
			<td style="width:212px;">OMEGA Engineering INC, Connecticut USA</td>
			<td style="width:212px;">FMA5416</td>
		</tr>
		<tr height="58">
			<td height="58" style="height:58px;width:212px;">Data acquisition card</td>
			<td style="width:212px;">Measurement Computing Corporation, Massachusetts USA</td>
			<td style="width:212px;">USB-1208FS</td>
		</tr>
		<tr height="39">
			<td height="39" style="height:39px;width:212px;">Filters</td>
			<td style="width:212px;">Aerocolloid LLC, Minnesota USA</td>
			<td style="width:212px;"> </td>
		</tr>
		<tr height="39">
			<td height="39" style="height:39px;width:212px;">MATLAB/Simulink</td>
			<td style="width:212px;">Mathworks, Massachusetts USA</td>
			<td style="width:212px;">R2010a</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:212px;">Glass bottles</td>
			<td style="width:212px;">Fisher USA</td>
			<td style="width:212px;"> </td>
		</tr>
	</tbody>
</table>

optimize flue gas settings to promote microalgae growth in photobioreactors via computer simulations

从电厂烟气能促进藻类栽培和减少温室气体排放1。微藻不仅比3的植物更有效地捕获太阳能，而且合成先进的生物燃料2-4。一般情况下，大气中的CO 2是不是有足够的来源，支持最大藻类生长5。另一方面，在高浓度的CO 2的工业废气对藻类的生理不良影响。因此，无论培养条件（如营养物和光），并在烟道气流进入光生物反应器的控制是重要的，以开发一种有效的"烟道气藻类"系统。研究者提出了不同的光生物反应器配置4,6和培养战略7,8烟气。在这里，我们提出了一个协议，它演示了如何使用模型来预测响应微藻生长烟气设置。我们PERFORM两个实验说明和模型模拟，以确定烟气藻类生长的有利条件。我们开发了一个莫诺基于模型加上传质和光强度的公式来模拟在均匀光生物反应器的微藻生长。该模型模拟比较藻类生长和烟气消费在不同烟气设置。该模型说明:1）如何藻类的生长是由CO 2的不同体积传质系数的影响; 2）我们如何可以通过动态优化方法（DOA）找到最优的CO 2浓度为藻类生长; 3）我们如何设计一个矩形的通断烟气脉冲，以促进藻类生物量增长，以减少烟道气的使用量。在实验方面，我们提出了一个协议，用于不断增长的小球藻烟道气（天然气燃烧产生的）下。实验结果定性地验证了模型预测的高频烟气普LSES可以显著提高藻类栽培。

我们以前的实验分析表明，连续烟气暴露产生不利影响小球藻生长，同时降低二氧化碳曝光时间能缓解这种抑制作用13。为了更好地理解烟气流入和藻类生长的关系，我们开发的实证模型来模拟生物量生长在烟气的存在。我们假设在烟道气中含有15％的CO 2（注:从煤燃烧的典型的CO 2浓度为10-15％，而从氧燃烧电厂的烟道气具有的CO 2&gt; 15％）。的传质?...

Watch this Scientific Journal Video about Optimize Flue Gas Settings to Promote Microalgae Growth in Photobioreactors via Computer Simulations at JoVE.com

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

从电厂烟道气是一种廉价的CO 2源藻类生长。我们已经建立原型"烟气海藻栽培"系统并描述如何扩大藻类培养过程。我们已经证明了使用一个传质生物反应模型来模拟，并设计烟道气的最佳操作小球藻的生长。藻光生物反应器。

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 ...

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14.2K 次观看.  Washington University in St. Louis, St. Louis. 从电厂烟道气是一种廉价的CO 2源藻类生长。我们已经建立原型"烟气海藻栽培"系统并描述如何扩大藻类培养过程。我们已经证明了使用一个传质生物反应模型来模拟，并设计烟道气的最佳操作小球藻的生长。藻光生物反应器。 

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

Analysis of Fatty Acid Content and Composition in Microalgae

A method to determine the content and composition of total fatty acids present in microalgae is described. Fatty acids are a major constituent of microalgal biomass. These fatty acids can be present in different acyl-lipid classes. Especially the fatty acids present in triacylglycerol (TAG) are of commercial interest, because they can be used for production of transportation fuels, bulk chemicals, nutraceuticals (&omega;-3 fatty acids), and food commodities. To develop commercial applications, reliable analytical methods for quantification of fatty acid content and composition are needed. Microalgae are single cells surrounded by a rigid cell wall. A fatty acid analysis method should provide sufficient cell disruption to liberate all acyl lipids and the extraction procedure used should be able to extract all acyl lipid classes.
With the method presented here all fatty acids present in microalgae can be accurately and reproducibly identified and quantified using small amounts of sample (5 mg) independent of their chain length, degree of unsaturation, or the lipid class they are part of.
This method does not provide information about the relative abundance of different lipid classes, but can be extended to separate lipid classes from each other.
The method is based on a sequence of mechanical cell disruption, solvent based lipid extraction, transesterification of fatty acids to fatty acid methyl esters (FAMEs), and quantification and identification of FAMEs using gas chromatography (GC-FID). A TAG internal standard (tripentadecanoin) is added prior to the analytical procedure to correct for losses during extraction and incomplete transesterification.

A method for the determination of fatty acid content and composition in microalgae based on mechanical cell disruption, solvent based lipid extraction, transesterification, and quantification and identification of fatty acids using gas chromatography is described. A tripentadecanoin internal standard is used to compensate for the possible losses during extraction and incomplete transesterification.

脂肪酸组分和含量微藻分析

A method to determine the content and composition of total fatty acids present in microalgae is described. Fatty acids are a major constituent of ...

科研

环境科学

Quantification of Heavy Metals and Other Inorganic Contaminants on the Productivity of Microalgae

Increasing demand for renewable fuels has researchers investigating the feasibility of alternative feedstocks, such as microalgae. Inherent advantages include high potential yield, use of non-arable land and integration with waste streams. The nutrient requirements of a large-scale microalgae production system will require the coupling of cultivation systems with industrial waste resources, such as carbon dioxide from flue gas and nutrients from wastewater. Inorganic contaminants present in these wastes can potentially lead to bioaccumulation in microalgal biomass negatively impact productivity and limiting end use. This study focuses on the experimental evaluation of the impact and the fate of 14 inorganic contaminants (As, Cd, Co, Cr, Cu, Hg, Mn, Ni, Pb, Sb, Se, Sn, V and Zn) on Nannochloropsis salina growth. Microalgae were cultivated in photobioreactors illuminated at 984 &#181;mol m-2 sec-1 and maintained at pH 7 in a growth media polluted with inorganic contaminants at levels expected based on the composition found in commercial coal flue gas systems. Contaminants present in the biomass and the medium at the end of a 7 day growth period were analytically quantified through cold vapor atomic absorption spectrometry for Hg and through inductively coupled plasma mass spectrometry for As, Cd, Co, Cr, Cu, Mn, Ni, Pb, Sb, Se, Sn, V and Zn. Results show N. salina is a sensitive strain to the multi-metal environment with a statistical decrease in biomass yieldwith the introduction of these contaminants. The techniques presented here are adequate for quantifying algal growth and determining the fate of inorganic contaminants.

Integration of microalgal cultivation with industrial flue gas will ultimately introduce heavy metals and other inorganic compounds into the growth media. This study presents a procedure used to determine the end fate and impact of heavy metals and inorganic contaminants on the growth of Nannochloropsis salina grown in photobioreactors.

重金属和微藻的产其他无机污染物的量化

Increasing demand for renewable fuels has researchers investigating the feasibility of alternative feedstocks, such as microalgae. Inherent advantages ...

Laboratory Simulation of an Iron(II)-rich Precambrian Marine Upwelling System to Explore the Growth of Photosynthetic Bacteria

A conventional concept for the deposition of some Precambrian Banded Iron Formations (BIF) proceeds on the assumption that ferrous iron [Fe(II)] upwelling from hydrothermal sources in the Precambrian ocean was oxidized by molecular oxygen [O2] produced by cyanobacteria. The oldest BIFs, deposited prior to the Great Oxidation Event (GOE) at about 2.4 billion years (Gy) ago, could have formed by direct oxidation of Fe(II) by anoxygenic photoferrotrophs under anoxic conditions. As a method for testing the geochemical and mineralogical patterns that develop under different biological scenarios, we designed a 40 cm long vertical flow-through column to simulate an anoxic Fe(II)-rich marine upwelling system representative of an ancient ocean on a lab scale. The cylinder was packed with a porous glass bead matrix to stabilize the geochemical gradients, and liquid samples for iron quantification could be taken throughout the water column. Dissolved oxygen was detected non-invasively via optodes from the outside. Results from biotic experiments that involved upwelling fluxes of Fe(II) from the bottom, a distinct light gradient from top, and cyanobacteria present in the water column, show clear evidence for the formation of Fe(III) mineral precipitates and development of a chemocline between Fe(II) and O2. This column allows us to test hypotheses for the formation of the BIFs by culturing cyanobacteria (and in the future photoferrotrophs) under simulated marine Precambrian conditions. Furthermore we hypothesize that our column concept allows for the simulation of various chemical and physical environments &#8212; including shallow marine or lacustrine sediments.

Laboratory Simulation of an IronII-rich Precambrian Marine Upwelling System to Explore the Growth of Photosynthetic Bacteria

We simulated a Precambrian ferruginous marine upwelling system in a lab-scale vertical flow-through column. The goal was to understand how geochemical profiles of O2 and Fe(II) evolve as cyanobacteria produce O2. The results show the establishment of a chemocline due to Fe(II) oxidation by photosynthetically produced O2.

一个铁（II）的实验室模拟的前寒武纪富海洋上升流系统探索光合细菌生长

A conventional concept for the deposition of some Precambrian Banded Iron Formations (BIF) proceeds on the assumption that ferrous iron [Fe(II)] upwelling ...

A Gusseted Thermogradient Table to Control Soil Temperatures for Evaluating Plant Growth and Monitoring Soil Processes

Thermogradient tables were first developed in the 1950s primarily to test seed germination over a range of temperatures simultaneously without using a series of incubators. A temperature gradient is passively established across the surface of the table between the heated and cooled ends and is lost quickly at distances above the surface. Since temperature is only controlled on the table surface, experiments are restricted to shallow containers, such as Petri dishes, placed on the table. Welding continuous aluminum vertical strips or gussets perpendicular to the surface of a table enables temperature control in depth via convective heat flow. Soil in the channels between gussets was maintained across a gradient of temperatures allowing a greater diversity of experimentation. The gusseted design was evaluated by germinating oat, lettuce, tomato, and melon seeds. Soil temperatures were monitored using individual, battery-powered dataloggers positioned across the table. LED lights installed in the lids or along the sides of the gradient table create a controlled temperature chamber where seedlings can be grown over a range of temperatures. The gusseted design enabled accurate determination of optimum temperatures for fastest germination rate and the highest percentage germination for each species. Germination information from gradient table experiments can help predict seed germination and seedling growth under the adverse soil conditions often encountered during field crop production. Temperature effects on seed germination, seedling growth, and soil ecology can be tested under controlled conditions in a laboratory using a gusseted thermogradient table.

Traditional thermogradient tables create a range of temperatures across the surface. Welding gussets perpendicular to the surface of a thermogradient table will control temperature in depth increasing possible research applications.

一个插角Thermogradient表来控制土壤温度为评估植物生长和监测土壤过程

Thermogradient tables were first developed in the 1950s primarily to test seed germination over a range of temperatures simultaneously without using a ...

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 ...

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

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 facilities. This protocol has been used to effectively evaluate many different bedding materials, environmental variables (temperature, humidity), and potential mitigation treatments that can improve air quality in commercial deep-bedded mono-slope facilities. The model is dynamic and allows researchers to easily collect many chemical and physical measurements from the bedded pack. Weekly measurements, collected over the course of six to seven weeks, allows sufficient time to see changes in air quality measurements over time as the bedded pack matures. The data collected from the simulated bedded packs is within the range of concentrations previously measured in commercial deep-bedded mono-slope facilities. Past studies have demonstrated that 8 - 10 experimental units per treatment are sufficient to detect statistical differences among the simulated bedded packs. The bedded packs are easy to maintain, requiring less than 10 minutes of labor per bedded packs per week to add urine, feces, and bedding. Sample collection using the gas sampling system requires 20 - 30 minutes per bedded pack, depending on the measurements that are being collected. The use of lab-scaled bedded packs allows the researcher to control variables such as temperature, humidity, and bedding source that are difficult or impossible to control in a research or commercial facility. While not a perfect simulation of &#34;real-world&#34; conditions, the simulated bedded packs serve as a good model for researchers to use to examine treatment differences among bedded packs. Several lab-scale studies can be conducted to eliminate possible treatments before trying them in a research or commercial-sized facility.

A protocol has been developed to measure gases, odors, and nutrient composition in lab-scaled bedded manure packs, which can be used to study ways to improve air quality in commercial cattle facilities using deep-bedded manure packs.

用实验室尺度模型评价深层包粪排放的恶臭和气体浓度

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 ...

Experimental Study of the Relationship Between Particle Size and Methane Sorption Capacity in Shale

The amount of adsorbed shale gas is a key parameter used in shale gas resource evaluation and target area selection, and it is also an important standard for evaluating the mining value of shale gas. Currently, studies on the correlation between particle size and methane adsorption are controversial. In this study, an isothermal adsorption apparatus, the gravimetric sorption analyzer, is used to test the adsorption capacity of different particle sizes in shale to determine the relationship between the particle size and the adsorption capacity of shale. Thegravimetric method requires fewer parameters and produces better results in terms of accuracy and consistency than methods like the volumetric method. Gravimetric measurements are performed in four steps: a blank measurement, preprocessing, a buoyancy measurement, and adsorption and desorption measurements. Gravimetric measurement is presently considered to be a more scientific and accurate method of measuring the amount of adsorption; however, it is time-consuming and requires a strict measuring technique. A Magnetic Suspension Balance (MSB) is the key to verify the accuracy and consistency of this method. Our results show that adsorption capacity and particle size are correlated, but not a linear correlation, and the adsorptions in particles sieved into 40 - 60 and 60 - 80 meshes tend to be larger. We propose that the maximum adsorption corresponding to the particle size is approximately 250 &#181;m (60 mesh) in the shale gas fracturing.

We use an isothermal adsorption apparatus, the gravimetric sorption analyzer, to test the adsorption capacity of different particle sizes of shale, in order to find out the relationship between particle size and the adsorption capacity of shale.

页岩中粒径与甲烷吸附能力关系的实验研究

The amount of adsorbed shale gas is a key parameter used in shale gas resource evaluation and target area selection, and it is also an important standard ...

An Optimized Rhizobox Protocol to Visualize Root Growth and Responsiveness to Localized Nutrients

Roots are notoriously difficult to study. Soil is both a visual and mechanical barrier, making it difficult to track roots in situ without destructive harvest or expensive equipment. We present a customizable and affordable rhizobox method that allows the non-destructive visualization of root growth over time and is particularly well-suited to studying root plasticity in response to localized resource patches. The method was validated by assessing maize genotypic variation in plasticity responses to patches containing 15N-labeled legume residue. Methods are described to obtain representative developmental measurements over time, measure root length density in resource-containing and control patches, calculate root growth rates, and determine 15N recovery by plant roots and shoots. Advantages, caveats, and potential future applications of the method are also discussed. Although care must be taken to ensure that experimental conditions do not bias root growth data, the rhizobox protocol presented here yields reliable results if carried out with sufficient attention to detail.

Visualizing and measuring root growth in situ is extremely challenging. We present a customizable rhizobox method to track root development and proliferation over time in response to nutrient enrichment. This method is used to analyze maize genotypic differences in root plasticity in response to an organic nitrogen source.

一种优化的 Rhizobox 协议, 用于可视化根系生长和对局部营养素的响应

Roots are notoriously difficult to study. Soil is both a visual and mechanical barrier, making it difficult to track roots in situ without destructive ...

Composition and Distribution Analysis of Bioaerosols Under Different Environmental Conditions

Variable microorganisms in particulate matter (PM) under different environmental conditions may have significant impacts on human health. In this study, we described a protocol for multiple analyses of the biological compositions in environmental PM. Five experiments are presented: (1) PM number monitoring by using a laser particle counter; (2) PM collection by using a cyclonic aerosol sampler; (3) PM collection by using a high-volume air sampler with filters; (4) culturable microbes collection by the Andersen six-stage sampler; and (5) detection of biological composition of environmental PM by bacterial 16SrDNA and fungal ITS region sequencing. We selected hazy days and a livestock farm as two typical examples of the application in this protocol. In this study, these two sampling methods, cyclonic aerosol sampler and filter sampler, showed different sampling efficiency. The cyclonic aerosol sampler performed much better in terms of collecting bacteria, while these two methods showed the same efficiency in collecting fungi. Filter samplers can work under low temperature conditions while cyclonic aerosol samplers have a sampling limitation for temperature. A solid impacting sampler, such as an Andersen six-stage sampler, can be used to sample bioaerosols directly into the culture medium, which increases the survival rate of culturable microorganisms. However, this method mainly relies on culture while more than 99% of microbes cannot be cultured. DNA extracted from the culturable bacteria collected by the Andersen six-stage sampler and samples collected by cyclonic aerosol sampler and filter sampler were detected by bacterial 16S rDNA and fungal ITS region sequencing.All the methods above may have wide application in many fields of study, such as environmental monitoring and airborne pathogen detection. From these results, we can conclude that these methods can be used under different conditions and may help other researchers further explore the health impacts of environmental bioaerosols.

Understanding the biological composition of environmental particulate matter is important for the study of its significant impacts on human health and disease spread. Here, we used three types of bioaerosol sampling methods and a biological analysis of airborne microbes to better explore airborne microbial communities under different environmental conditions.

不同环境条件下生物气溶胶的组成及分布分析

Variable microorganisms in particulate matter (PM) under different environmental conditions may have significant impacts on human health. In this study, ...

Cultivation of Green Microalgae in Bubble Column Photobioreactors and an Assay for Neutral Lipids

There is significant interest in the study of microalgae for engineering applications such as the production of biofuels, high value products, and for the treatment of wastes. As most new research efforts begin at laboratory scale, there is a need for cost-effective methods for culturing microalgae in a reproducible manner. Here, we communicate an effective approach to culture microalgae in laboratory-scale photobioreactors, and to measure the growth and neutral lipid content of that algae. Instructions are also included on how to set up the photobioreactor system. Although the example organisms are species of Chlorella and Auxenochlorella, this system can be adapted to cultivate a wide range of microalgae, including co-cultures of algae with non-algae species. Stock cultures are first grown in bottles to produce inoculum for the photobioreactor system. Algae inoculum is concentrated and transferred to photobioreactors for cultivation in batch mode. Samples are collected daily for the optical density readings. At the end of the batch culture, cells are harvested by centrifuge, washed, and freeze dried to obtain a final dry weight concentration. The final dry weight concentration is used to create a correlation between the optical density and the dry weight concentration. A modified Folch method is subsequently used to extract total lipids from the freeze-dried biomass and the extract is assayed for its neutral lipid content using a microplate assay. This assay has been published previously but protocol steps were included here to highlight critical steps in the procedure where errors frequently occur. The bioreactor system described here fills a niche between simple flask cultivation and fully-controlled commercial bioreactors. Even with only 3-4 biological replicates per treatment, our approach to culturing algae leads to tight standard deviations in the growth and lipid assays.

Here, we present a protocol to construct lab-scale bubble column photobioreactors and use them to culture microalgae. It also provides a method for the determination of the culture growth rate and neutral lipid content.

气泡柱光生物反应器中绿色微藻的培养及中性脂质的测定

There is significant interest in the study of microalgae for engineering applications such as the production of biofuels, high value products, and for the ...