Name: reaction kinetics and combustion dynamics of i4o9 and aluminum mixtures
Uploaded: 2016-11-07T15:00:00.000+00:00
Duration: 9 min 16 s
Description: Watch this Scientific Journal Video about Reaction Kinetics and Combustion Dynamics of I4O9 and Aluminum Mixtures at JoVE.com

The authors Smith and Pantoya are grateful for partial support from DTRA under award HDTRA1-15-1-0029; and, ARO (and Dr. Ralph Anthenien) under award W911NF-14-1-0250 and equipment grant W911NF-14-10417. The authors J. Parkey and M. Kesmez are grateful for support from DTRA under award HDTRA1-15-P-0037. Thank you to Dr. Douglas Allen Dalton for helpful discussion.

注:六种不同的氧化剂进行了调查，相较于其他的碘氧化物表征的我4 O 9的动力学的目的。每个氧化剂进行说明。用于所有的混合物的燃料是常数:Al粉具有80纳米平均球形颗粒直径。混合配制是按照每个氧化剂的讨论描述。 1.碘（V）催化剂的制备注:纳米铝/氧化混合物，极易挥发，可以表现出具有爆炸性。这些混合物容易受到静电放电，摩擦，冲击，以及其他形式的意外点燃的无意点火。所有设备应接地，以减少意外火花点火的可能性。数量应该被最小化，并且处理这些材料时，保护设备应该被使用。安全性和处理程序的更多信息可在Maienschein 等人发现。18 <ol><li> P商业赔偿我2 O 5 <ol><li>粉碎将10克I 2 O 5的结晶用研钵和杵，直到创建一个一致的粉末。 </li><li>后的晶体在粉末形式，均匀地散布10克的粉末在适于加热到250℃的陶瓷坩埚内。 </li><li>放置在烘箱中，并加热到250℃的整个坩埚以10℃/分钟，在250℃下保持5分钟。 </li></ol></li><li> 非晶I 2 O 5准备 <ol><li>放置3个克粉碎和脱水商业我2 O 5的有磁性搅拌器的玻璃烧杯中，加入3克蒸馏水。以确保样品完全溶解后，加一个1:水商业我2 O 5比1的比例，并混合20分钟。的我2 O 5在水中的形式的IO 3的水相中溶解。17 </li><li>倒在IO 3溶液成喙呃适合于加热。以确保足够的非晶我2 O 5 的产生，使用的IO 3溶液三次质量比需要的无定形我2 O 5的质量。例如，如果需要的无定形我2 O 5 的一克用3克IO 3溶液。 </li><li>放置烧杯与IO 3溶液放入烘箱和加热，在20℃/分钟至250℃并保持10分钟。 </li><li>储存样品在密闭容器中，以限制从环境暴露于大气中的水。 </li></ol></li><li> 制备结晶HIO 3 <ol><li>重复步骤1.2.1和地点的IO在磁力搅拌器3溶液在低湿度环境（低于50％RH）中，直到所有的过量的水的蒸发。在蒸发时，IO 3的水相将沉淀出作为HIO 3 17。 </li><li>储存样品在密闭容器中，以限制Èxposure从环境大气中的水。 </li><li>以确保所有过量的水被蒸发，放置样品放入差示扫描量热计（DSC）和热至250℃以10℃/分钟。 注意:在110℃的重量损失将等于5％，将有在210℃无质量损失，如果样品是纯HIO 3。任何额外的质量损失是过量的水，这意味着样品需要更多的时间来蒸发。在210℃的重量损失代表I 2 O 5 的未完全溶解，并且需要在搅拌更多的水以溶解样品。 </li></ol></li></ol> 2.制浆注:混合物在两种不同的方法制得:使用一个载体流体之一的掺混和另一个帮助没有载体流体而是干混合。对于使用载体流体处理，混合物为只有三个氧化剂制备:我4 O 9，纳米我2 O 5和COMMErcial I 2 O 5。 <ol><li> 混合物在载流体制备 <ol><li>为了制备在载体流体混合的样品中，与每个氧化剂为总共2克Al和氧化剂混合物的至1​​.0在烧杯中的当量比混合80纳米的Al粉末。 </li><li>加60毫升异丙醇放入烧杯中，并超声处理用声波棒设定在编程用于10秒上和10秒关，总共2最少4瓦的输出功率的溶液。 </li><li>倾溶液放入玻璃盘，并允许该溶液在通风橱中在室温下用20％的相对湿度下24小时，这将留下的粉末样品蒸发。 注:在与步骤2.1.4出发，保证刀片被连接到电接地用导电线，以避免意外着火。 </li><li>带有接地刀片回收粉末和筛样品直接打破团块成可以密封到利米一个容器ŧ样本暴露在大气中的水。 </li></ol></li><li> 干混样品的制备 <ol><li>筛并用刮铲混合2克Al和氧化剂混合物的进入样品容器到燃料到1.0氧气量比。密封该样品容器，以限制样品暴露于大气中的水。 </li><li>握住振动台样品3分钟，以助于混合。参考以这种方式为干燥混合制备的样品。 </li></ol></li></ol> 3.热平衡分析<ol><li> 样品的制备热平衡分析 注:这些样品与大气中的水容易起反应。相对湿度应在30％以下，并暴露降低到大气中应限制（ 即 ，存储样品在密封的容器和使用盖子上的DSC-TGA坩埚）。 <ol><li>热氧化铝坩埚中（使用DSC-TGA诊断提供）到1500℃，并保持30分钟以消除任何残留物在DSC-TGA坩埚。 </li><li>称量坩埚的样品被放置在坩埚之前。这种测量是由DSC-TGA需要的。 </li><li>坩埚称重后，加入10毫克的每种样品到坩埚。 </li><li>放置在DSC-TGA热电偶试样坩埚中在DSC热电偶的基准保持器的空坩埚中。 </li><li>在10℃/分钟至600℃在氩气氛中加热该样品。 </li></ol></li></ol> 4.能量的传播<ol><li> 火焰管的制备 <ol><li>使用石英管具有3毫米内径和7厘米长，以包含所述粉末混合物。 </li><li>穿上一端磁带所以粉末不能从管逸出。 </li><li>将每个7厘米管一端贴在规模和零刻度。这将允许粉末的只是质量的测量。 </li><li>用锅铲与小端，将粉末样品到日Ë管。对于每种混合物，使三个管填充有各混合物重复性测试。 </li><li>使用具有直径小于3mm，紧凑管内的粉末对于具有低堆积密度的样品的杆（ 即 ，铝+ I 4 O 9和Al +非晶硅我2 O 5），直至样品的体积不不变。这个过程是需要维护多个实验之间是一致的堆积密度。这可能需要200毫克的粉末混合物。 </li><li>对于所有其他的混合物，其具有更高的密度，不使用外力压缩粉末。保持堆积密度具有类似的堆积密度的样品之间恒定。粉末在管中的量将根据该粉末的堆积密度而变化。这可能需要高达500毫克的粉末混合物。 </li><li>使用已配衡的每个管的平衡测量粉末混合物中的每个管中的质量，增加质量，直到粉末的密度为within各自组中的其它样本的5％。确保每个管被完全填满。 </li></ol></li><li> 热丝点燃的制备 <ol><li>为了准备火线，使用镍铬（ 即镍铬合金）线切段长10厘米。 </li><li>做一个"V"形中的线的中间，放置导线使"V"形是在管内。 </li><li>大盘管的这一端，以便线是固定的，没有粉能逃过管。 </li></ol></li><li> 高速摄影机的研制 <ol><li>放置在燃烧室外部的高速摄像机垂直于火焰传播的方向，并通过在燃烧室观察口集中在管的相机。 注:在燃烧室的主要功能是保护人员和设备从反应材料，并应通过通风柜进行通风。 </li><li>调整日的位置和镜头Ë相机所以最低分辨率（ 即 ，最高帧速率）都可以使用。 </li><li>以允许距离校准，放置具有毫米和厘米增量标尺中的视场，并记录火焰速度之前采取与高速照相机快照。 </li><li>由于火焰前缘比环境光显著明亮，相机将过饱和时暴露于由反应所产生的光，降低了曝光时相机的设置或者添加中性密度过滤器，照相机的透镜，以减少的量光由相机传感器接收。降低光的由照相机接收直到反应的传播前可以清楚地看到的量。这里，设置了中性密度滤光片仅允许5％的光的通过，以及1微秒的曝光时间。 </li><li>附加一个电压发生器的电线的端部。燃烧室应该绝缘通过室引线，这将允许该腔室被密封并允许金属丝的远方加热。 </li><li>该腔室被密封之后，所述电压发生器设置为10伏，同时开始相机记录。当施加电压时，反应应当几乎立即开始。 </li><li>导出视频到一个软件程序，将跟踪作为时间在每个单独的帧的函数的火焰前缘的位置。 </li><li>导出的距离和时间步长信息到扩展板和积有R 2值的线性趋势线。对于较慢的反应，需要一种用于在反应达到稳定状态的时间。前的稳定状态时的曲线将是一个指数增加的曲线。删除不处于稳定状态，直到R 2值大于0.95的数据。该直线的斜率是火焰速度。 </li></ol></li></ol>

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这里研究了我4 O 9粉末用"干"的方式通过组合元素碘和氧气以形成我4 O 9合成。该样品被称为I 4 O 9。纳米粒子的I 2 O 5也被合成了这项研究。具体而言，我4 O 9的部分被加热过去的我4 O 9（ 即 180℃）的解离温度，但我2 O 5（400℃）的分解温度之下。这个过程导致颗粒200-400纳米之间的直径。此样品被称为纳米我2 O 5等。粒径测量通过TEM获得这要求样品是在一个真空。然而，我4 O 9离解成我2 O 5在真空中，所以没有直接得到的我4 O 9的尺寸。由于纳米我2 O &lt;子&gt; 5粒径为200-400纳米，通过加热我4 O 9样品合成之间，假设我4 O 9具有类似的直径。 以合成I 2 O 5更常见的方法是通过碘酸热脱水形成I 2 O 5 1,2,8和材料制成，采用这种工艺的商业化。商业我2 O 5被接收作为粗大的结晶，并且可以具有不同浓度的依赖于储存和处理条件下碘酸。为了保证样品是纯I 2 O 5，样品脱水之前使用步骤2.1.1.3作为解释。此示例中的颗粒的直径是1-5μm之间。此样品被称为商业我2 O 5等。 非晶I 2 O 5样品从这个饱和IO 3溶液制成<html> 。当我2 O 5与水混合，将创建IO 3的溶液。这在步骤2.1.2完成，这些步骤将离开饱和IO 3溶液。水催化晶体在碘酸的形成。为了形成非晶我2 O 5 的温度必须高于在，将不会允许的晶体结构，以形成一个速度HI 3 O 8和加热的脱水温度，这是在步骤1.2进行。 IO 3的在溶液中的浓度将决定脱水过程中产生的无定形我2 O 5的量。脱水后，指示所述样品是第I 2 O 5 的无定形形式，这些样品应变红。该样品被称作无定形我2 O 5等。另外，X射线衍射分析（不含税）的预制并证实了我4 O 9和非晶我2 O 5个样品的无定形结构。 ENT"&gt;当在溶液中，HIO 3将释放过量的水，并创建一个晶体结构。以蒸发过量水所需的时间是依赖于烧杯中，相对湿度，和IO 3溶液的浓度的大小。在我们的实验室在在上述方式20％RH下的混合，被要求3-5天以从样品蒸发过量的水。将溶液会变成固体透明水晶，这个过程示于步骤2.1.3和样品称为HIO 3脱水。碘酸将被称为商业HIO 3。 当暴露于溶液或大气水，碘（V）的氧化物发生了改变最终产物的组成的化学反应。为了减轻这种转变中，所有六个氧化物也与Al混合无解。 使用DSC-TGA热分析中使用的样品与已知的起始温度和质量损失在氩气氛中进行校准。火焰管过仪器称为Bockmon管23是用于测量火焰速度。火焰速度实验​​是对混合物的堆积密度敏感。 Pantoya 等人表明，对于基于纳米的Al thermites，增加堆积密度，可以抑制铝的反应机理和减少对流能量输送，从而阻滞火焰速度24的作用。出于这个原因，对于不同的混合物进行的实验通常被设计，以保持恒定的堆积密度。然而，在这里检查了氧化剂的物理和化学性质而变化显着，使得其不可能获得一致的堆积密度与所有六个干混合物。由于这个原因，多碘氧化物具有不同的物理和化学性质进行测试，以提供比较的基础，其中包括晶体结构的水合状态在％TMD的差异，和。该粉末已被放置在管内之后与测得的，热丝用于远程点燃该混合物。火焰管与粉末混合物制备后，火焰速度被在燃烧室中使用高速摄像机测量。摄像机的帧速率可通过降低分辨率增加。降低分辨率来提高帧速率会产生更小的误差比在较慢的帧速率更高的分辨率。这就是为什么，在步骤4.2.2，最低的分辨率，可以静止图像被使用的整个火焰筒，这将增加每秒照相机可以在不丢失信息记录最大帧。对于我们的房间，256×86的分辨率使用这使得相机记录30万帧。 在高度反应混合物定量火焰速度是由于大量的可能影响反应变量固有地困难的（ 即 ，混合物的均匀性，粒度，密度，传播方向，传播速度， 等 ）。通过使用石英管的内diameteř小于4mm，结合一个高速照相机与中性密度过滤器，传播方向被控制（ 即 ，1-D）和由所述照相机接收的光的量可减少到最小阈值，使得光的通过反应发出的前缘可以看出，并明确测量。该测定假定该微光的进展是在相同的速率在反应前。因为这个原因，光电二极管可能不用于跟踪该反应的传播作为准确，因为发射的高光强度可能会引起光的旅行和饱和传感器比反应更快。另外，第一1-2厘米管长被认为是一个入口区，或不稳定或加速传播的区域。作为时间的函数的距离的线性测量必须采取超出这个入口区域，以确定稳定状态的火焰速度。 在DSC / TGA是一种热平衡分析认为SHOws的那些不能在高度反应性材料可以观察到的详细反应动力学（ 即 ，不能被非热平衡的条件下观察到的）。 DSC / TGA分析和火焰速度的结合，提供有关在可能对在火焰速度结果的差异影响反应动力学差别的具体信息。正因为如此，这两种测量方法的组合对于理解和控制的高反应性材料的有力工具。

有许多氧化碘化合物（ 如 HIO 3，HI 3 O 8，I 2 O 5，我4 O 9），但一个最常见的研究与铝（Al）的反应是碘化五氧化二磷，我2 O 5 1 - 16。是有原因的有利于我2 O 5燃烧与Al:（1）I 2 O 5有五氧化态，这使得它强氧化剂燃烧应用; （2）I 2 O 5是半稳定，这取决于大气条件，和粉末形式的易于处理;和（3）I 2 O 5是比较容易产生和容易得到的。 已经研究氧化物碘其他形式的HIO 3，HI 3 O 8，和我4 O 9。当加热到低温（ 即 180℃），我4 O 9的rmally分解成I 2 O 5 6如公式（1）和分解反应是放热的。 （1）5I 4 O 9→9I 2 O 5 + I 2 如果我4 O 9可以在适当的位置使用的我2 O 5，从反应中释放可能增加的总能量由于我4 O 9放热分解在温度在Al点火和反应温度（ 即 ，&lt;660℃以下）及以下的我2 O 5（ 即 ，约350℃）的解离温度。另外，相比于我2 O 5，其可以被用于中和生物制剂，当我4 O 9产生8重量％以上的 I 2的气体。然而，相对于我2 O 5时，我4 O 9具有较高的分子量，这是未知的，如果更多的能量是我用4 O 9相比，I 2 O 5时，单位质量或单位体积的释放。我使用4 O 9可以提供一种方式来传输大量燃烧后固体碘，并释放出气态碘。但是，我4 O 9粉末通常是不稳定的。事实上，Wikjord 等 6表明，在很短的时间内我4 O 9分解成我2 O 5即使暴露限定到大气中。这种不稳定性限制了我4 O 9的实用性在燃烧应用氧化剂。 碘酸，如HIO 3和HI 3 O 8，当我2 O 5是无论是从大气的相对湿度（RH）或从浸没在流体1,3暴露于水的形式。用于燃烧应用中，我2 O 5通常优选在水合碘酸因为evaporati上的在燃烧时的水吸收能量并降低所产生的总热量。尽管该相变的吸热性质，Smith等 3表明的水快速蒸发的Al燃烧过程中与I 2 O 5 的组成的部分碘酸酸产生显著气体产生该增加对流能量传输和比铝产生较高的火焰速度+我独自一人2 O 5。具体地说，具有较高浓度的碘酸的混合物具有高达300％的火焰速度比具有较低浓度的碘酸的混合物。3 从大气中的水吸收率是依赖于湿度。有在那里吸收开始一个RH阈值，并且依赖于水合状态2。 Little等显示出70％的相对湿度门槛HIO 3和40％的HI 3 O 8 2 RH阈值。从这一点，假定相对湿度阈值随着水合状态而增加。由于其潮解的特性，使用I 2 O 5作为氧化剂大部分研究实际上是利用I 2 O 5与显著浓度碘酸2,5,7,17的。然而，样品的初始浓度可以通过加热上述210℃的样品，直到所有的水合物种的已脱水来控制。这如下式（2）中Selte 等 1所示的我2 O 5的水合和脱水机构。 （2A）水化:3I 2 O 5 + 3H 2 O→2HI 3 O 8 + 2H 2 O→6HIO 3 （2B）脱水:6HIO 3→2HI 3 O 8 + 2H 2 O→3I 2 O 5 + 3H 2 O 在脱水的第一步骤发生在110℃时HIO 3 dehydr阿泰到HI 3 O 8。脱水的第二个步骤发生在210℃时，HI 3 O 8脱水成I 2 O 5。因为市售的初始浓度I 2 O 5大部分是由碘氨基酸组成，纯I 2 O 5的吸收特性没有得到深入的研究。假定相对湿度阈值和吸收速率取决于随着初始水合状态和碘氧化物是无定形的可能具有较低的相对湿度阈值和增加的水合速率的物理性质（ 即 ，粒径，晶体结构）。从大气中的水分离碘氧化物的需要控制碘化氧化合物的初始状态。从大气中分离我2 O 5的一种方法是阻断吸水率用包衣。例如，Little等能够减少吸收率和Hy的总量drated碘的氧化物与金/钯2溅射镀膜样品。 Feng等 8钝化我2 O 5颗粒的表面与防止过度暴露于环境气氛的长持续时间的吸水率的Fe 2 O 3涂层。类似的方法可以适用于帮助稳定我4 O 9。 另一种方式，以提高我4 O 9的稳定性可以是用于其合成的新方法。如果材料能够在阻止引入水合物种的方法来合成，然后催化吸水率局部化学作用可由此抑制稳定的氧化剂。在我4 O 9检查在这里用"干"的过程，不会引入水合品种，使我4 O 9粉末更稳定形式的分析合成。我们的目标是分析的根本动力学associatED与我4 O 9分解反应与Al以及铝+ I 4 O 9反应的基本能量传播行为。反应动力学是使用热平衡诊断包括差示扫描量热法和热重分析（DSC-TGA）分析。能量传播通过在透明管在点火的粉末混合物使用反应传播的高速成像进行分析。的合成方法研制生产我4 O 9和方法来稳定我4 O 9也相对于其他形式的氧化碘缓慢。本研究的目的是表明，能源和天然气涉及到我4 O 9比涉及其他碘的氧化物反应较大的反应中解放出来。这样一来，未来的合成与我4 O 9表征的研究可能对许多应用是有益的。

<table><tbody><tr><td>Iodine pentoxide (Commercial I&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;5&lt;/sub&gt;)</td><td>Sigma Aldrich</td><td>229709</td><td>Commercial I&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;5&lt;/sub&gt;</td></tr><tr><td>Iodic Acid (Commercial HIO&lt;sub&gt;3&lt;/sub&gt;)</td><td>Alfa Aesar</td><td>A11925</td><td>Comercial HIO&lt;sub&gt;3&lt;/sub&gt;</td></tr><tr><td>Tetraiodine nonoxide (I&lt;sub&gt;4&lt;/sub&gt;O&lt;sub&gt;9&lt;/sub&gt;)</td><td>Lynntech Inc</td><td></td><td>synthesized using a dry process</td></tr><tr><td>Water</td><td></td><td></td><td>Local distilled water run through micron filter</td></tr><tr><td>80 nm Aluminum</td><td>NovaCentrix</td><td>AL-80-P</td><td>Nano Aluminum</td></tr><tr><td>Differential Scanning Calorimeter with Thermal Gravimetric Analyzer (DSC-TGA)</td><td>Netzsch</td><td>STA-449</td><td>Equilibrium analysis of heat flow and mass loss</td></tr><tr><td>Sonic Wand</td><td>Misonix</td><td>Sonicator 3000</td><td>Provides ultrasonic waves to aid intermixing of reactant powders</td></tr><tr><td>Phantom High Speed Camera</td><td>Vision Research</td><td>Phantom 2512</td><td>High speed camera for visualzing flame front</td></tr><tr><td>Mass Balance</td><td>Ohaus</td><td>Ohaus Explorer</td><td>Weigh powders with a 0.1 mg resolution up to a 110 g capacity</td></tr></tbody></table>

reaction kinetics and combustion dynamics of i4o9 and aluminum mixtures

Tetraiodine非氧化物（Ⅰ4 O 9），使用相结合的元素氧和碘不引入水合物种的干燥方法已经合成。合成途径抑制局部化学作用，当暴露于环境空气的相对湿度促进快速水合。使用差示扫描量热法（DSC）和热重分析（TGA）分析此稳定，无定形，纳米颗粒材料并表现出在低温下（ 即 180℃）的放热能量释放的我4 O 9转变成我2 O 5。这种额外的放热能量释放有助于的增加总体反应我4 O 9干燥时具有纳米铝（Al）粉末混合，从而导致在火焰速度至少150％的增加相比的Al + I 2 O 5等。这项研究表明，作为氧化剂，我4 O 9具有更比其他形式的碘（V）的氧化物的反应电位时与Al结合，特别是如果我4 O 9可以被钝化以抑制从其周围环境吸收水分。

图1a示出了初始状态的从DSC分析检查所有六个氧化剂的吸热和放热行为和图1b示出了从TGA分析的相应的质量损失。应该注意的是，当超出第I 2 O 5（350℃）的解离温度下加热所有氧化剂温度低于所述输100质量％，但我4 O 9样品释放，而不是通过水合物种的脱水解放水我2气分解温度的I 2 O 5。我2气体从我释放的丰度在图1b超过7重量指定4 O 9的样品。％。 图1a示出了产生放热行为的唯一碘化合物为I 4 O 9和I由形成2 O 5 的我4 O 9分解，放热对应于约180℃的起始温度为分解成I 2 O 5等。 图1b还示出了碘化合物具有最大的总碘气体产生是我4 O 9。 有商业和非晶我110℃和210℃之间2 O 5 的试样没有吸热。这表明，这些样品是纯粹的I 2 O 5，无碘酸。纳米I 2 O 5和我4 O 9与150℃起始温度放热。这说明这些样品中含有我4 O 9 6。纳米我2 O 5热处理我4 O 9。在150℃下的小放热表明，有一些残留的我4 O 9在纳米我2 O 5 的样品。使用从图1b的TGA数据中，样品中的残留我4 O 9是小于15重量％。所述HIO 3脱水有一个单一的吸热开始于130℃，表明该样品为结晶HIO 3。商用HIO 3样品具有开始在160℃和210℃两个不同的吸热。为160℃的开始温度的吸热是HIO 3脱水在CRC手册16的范围之外。然而，TGA结果表明2.47％（重量）在该范围指示它是水合物种的脱水质量损失。 图2a示出从四个铝DSC分析和碘乙烷的混合物的热量的流动行为。在Al + I 4 O 9干燥的混合物具有在180℃下，指示所述氧化剂放热仍然我4 O 9具有增加的起始温度。铝+ I 4 O 9和Al +纳米我2 O 5个样品几乎是相同的。这两种的混合物用异丙醇作为载体流体以有助于相互混合，并在图2a可见，表明在异丙醇混合粉末转化我4 O 9为I 2 O 5 的相同的热行为进行处理。 图2b示出了我4 O 9，我4 O 9暴露于20％RH下持续4小时，和纳米我2 O 5 的暴露于20％RH下进行4小时。 4小时后暴露在20％相对湿度，我4 O 9是相同的纳米我2 O 5和有在110℃和210℃显示了样品吸热部分地由HIO 3和HI 3 O 8的。这可以通过在I进行说明4 O 9"干"的合成方法，然后加热，并转化到我2 O 5的C我4 O 9 rystal结构是不知道，但由于水化观测（ 图2b带遮阳吸热底部两条曲线），粉（ 即 ，蓬松，高多孔性）的密度低，并且缺乏报道结晶结构中，假设无定形结构。纳米I 2 O 5是由无定形我4 O 9热分解根据公式形成。 （1），这样我2非晶我4 O 9离开非晶我2 O 5日发布。碘（V）的氧化物的晶体结构的形成是由水催化。由于该合成方法是干的，没有水催化形成晶体。对水的吸收所需要的第一个步骤是提高相对湿度破坏分子间的键。如果没有这种晶体结构（即希望释放弱结合水）的动态平衡被移位，所以我2 O 5 </sub&gt;会吸收任何可用的水。一旦水被我2 O 5，HIO的形成3分子开始吸收。 HIO 3具有吸引非晶I 2 O 5氧气，并创建一个HI 3 O 8晶体结构的氢。水仍然在晶体结构形成的催化剂。的我2 O 5和合成方法我4 O 9构成的无定形结构，而不是一个晶体结构是吸水性在较低的相对湿度被看作原因（ 即 ，20％），比被要求以开始在以前的研究吸收（什么即 ，70-80％RH）5,17。总之，碘化合物"无定形结构可以促进水合物种和形成的碘酸的吸收。 在图2a中500℃左右的主要放热都是相似的。在铝+ I 4 O 9干拌，在约180℃放热表示从我4 O 9 I 2 O 5相变。此外，所有的混合物具有一个预燃反应（PIR）300之间- 400℃，但铝+ I 4 O 9和Al +纳米我2 O 5 的具有红外较低起始温度和更大的数量级，但也显示出独特的吸热接着在210℃的放热。这些样品中的异丙醇的处理，并在210℃下的行为表明这些样品是部分HI 3 O 8。放热可能是HI 3 O 8和我4 O 9，因为HI 3 O 8游离在几乎相同的温度之间的反应，因为我4 O 9分解。这些反应可能有助于促进PIR更大的放热和催化PIR较早出现。奥斯本和Pantoya 20首次展示之前的主要放热反应，放热反应离子铝燃烧和创造这样的PIR。其分析表明PIR反应是从分解含氟19,20周围用氟铝芯颗粒氧化铝壳之间。法利等人的PIR的与基于碘氧化剂反应的铝-氧化铝核-壳粒子4然后扩展的观察。铝+商用I 2 O 5样品在210℃表明HI 3 O 8的存在和温和的PIR放热与迟发温度吸热。穆兰巴等人 21还表明，PIR开始温度为浓度依赖性。 表1测得的火焰速度结果A1显示与指示的氧化剂混合，干燥混合物，并用异丙醇作为加工载液也混。只有前三个样品在异丙醇和Al +共混合后测试mmercial HIO 3干混要么不点燃或没有反应持续足够长的时间来获得可衡量的结果。百分比不确定性是根据对每个混合物最多三个独立实验的重复性确定。堆积密度被确定为混合粉末的质量和管的体积的函数。 当解释与火焰传播速度的测量的反应性，有影响的结果，如混合物的均匀性，粒度和堆积密度的因素很多。混合物的均匀性可使用载体流体以帮助反应物相互混合进行优化。在这项研究中检查了我4 O 9比以前研究我4 O 9的样品和并未以分解成在Wikjord 等人看见我2 O 5，或形成水合物种更稳定。6（如见于图1a只对应于放热我4 O 9分解）。然而，只有这样，才能观察的Al的燃烧性能+ I 4 O 9是通过用尽可能少暴露在大气中尽可能干式混合，以保持第I 4 O 9的完整性。此外，铝的火焰速度的测量在不同状态下的氧化剂使我们能够缩小，在火焰速度的结果导致方差的影响，并揭示了特别归因于特定碘化合物的差异。这些比较将在下面讨论。整体表1表明，我当与其它碘化合物相比4 O 9显著提高反应性。 在一个载体流体混合提供了改进的燃料和氧化剂的颗粒分布，增加混合物的均匀性和反应性。这被认为是在在火焰速度差在表1中的干燥和异丙醇铝混合纳米+ I 2 O 5和Al +商业的我2 O 5个样品，其中火焰分别加快在增加了1.07和3.34倍。混合物的均匀性，从所测量的火焰速度隐含仅稍微为在Al +纳米我2 O 5 的混合物的改善，而铝+微米规模的商业我2 O 5表现出三次在火焰速度提高载体流体助剂相互混合时。明确颗粒尺寸和载体流体向测量的火焰速度。的均匀性的效果也可以通过火焰速度之间的不确定性看到。了在异丙醇中，并用较小的颗粒样品混合的样品在测定火焰速度较少的不确定性。这个小的不确定性还可以看出在所有的无定形的样品，这表明无定形结构有助于在干式混合改进均匀性。它进一步指出，每个样品过筛干燥混合之前分手结块并有助于消除造成同质性较差的不确定性。 所述HIO 3分子具有氢端盖，这是阳电和氧端盖，这是负电，并导致个体HIO 3分子22的端部之间的吸引力。正因为如此吸引力，筛分HIO 3粒子瞬间期间团聚铝可以混合之前。这导致同质性极差的原因是铝+商业HIO 3个样本无法维持的反应。在Al + HIO 3脱水样品具有可用来催化晶体结构的形成（ 图1a），这减少了水，但并未消除这种影响。 能量传播依赖于反应混合物的堆积密度。的密度将根据反应物的浓度改变，所以混合物的堆积密度通常报告为理论最大密度（TMD）的百分比。所述％TMD使用浓度的加权平均，并根据其质量和体积占用的实际样品的密度的反应物和账户的密度来计算。以这种方式，在％TMD方面堆积密度表示由体积占用固体空间量（ 即 ，60％的TMD是相当于40％的空气空隙和60％的固体）。低TMD％通常会导致更高的火焰速度比高％TMD粉末。空隙率的低TMD％的较高浓度提供对流通道，以提高火焰速度。出于这个原因，在表1中所报告的火焰速度没有可比性作为混合物的一个功能，因为每个在一个离散不同堆积密度制备。 （1）I 4 O 9:两个结论可以从表1可以得出不能在异丙醇被处理，因为它改变成I 2 O 5和因此改变其反应性和（2）I 4 O 9比我2 O 5 的更具反应性的，因为在较高的和较低的堆积密度（ 即 ，11％的TMD具有8个或17％的TMD相比），我4 O 9演示了增加的反应。这一发现表明，我4 O 9将是反应性应用是有利的，如果它可以被钝化以提高稳定性。 通过反应性和热分析，结果表明，我4 O 9可以是比其他形式的碘更易反应（Ⅴ）当与铝（Al）粉末组合氧化物。这里使用的我4 O 9样品用结合元素氧和碘，使得水合物种不会在合成过程中的任何点引入一个"干"方法合成的。出于这个原因，在I 4 O <sUB&gt; 9样品最初缺乏碘酸和在对应于它的分解的低温下（ 即 180℃）产生大的放热成I 2 O 5等。由第I 4 O 9热分解产生的纳米尺度我2 O 5粒子容易非晶质，当与Al粉（ 见表1）合并的超过1000米/秒产生火焰速度。铝+ I 4 O 9反应超过1500米/秒产生的火焰速度。这是第一次研究，探索的我4 O 9的潜力，以替代I 2 O 5能源发电技术，特别是高碘气体的产生激励。 <img alt="图1" src="/files/ftp_upload/54661/54661fig1.jpg" /> 图1. 质量损失的热流/ TGA分析DSC分析。a）他在从六个氧化剂DSC分析流动特性，并显示碘（Ⅴ）的氧化物中碘酸脱水。b的范围内使用）的不同状态从相应的TG分析质量损失。 <img alt="图2" src="/files/ftp_upload/54661/54661fig2.jpg" /> 图2. 热流的DSC分析。a）由DSC分析铝+ I 4 O 9的干混和Al + I 4 O 9，铝+纳米I 2 O 5和Al +商业I 2 O 5混合式流动行为在异丙醇中。温度范围包括I 4 O 9最初和I 4 O 9暴露于20％RH下进行4小时碘酸脱水和主要反应温度范围。b）中 。此外，我2 O 5被暴露于20％RH下进行4小时。 <table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within页="总是"&gt; <tbody><tr><td> 氧化剂 </td><td> 异丙醇混合火焰速度（米/秒） </td><td> ％的不确定性 </td><td> 干混火焰速度 </td><td> ％的不确定性 </td><td> 堆积密度干混（克/厘米3） </td><td> 干混％TMD </td></tr><tr><td>我4 O 9 </td><td> 1261 * </td><td> 0.4 </td><td> 1551 </td><td> 3 </td><td> 0.48 </td><td> 11.7 </td></tr><tr><td>纳米I 2 O 5 </td><td> 1146 </td><td> 4.5 </td><td> 1070 </td><td> 3.7 </td><td> 0.33 </td><td> 8 </td></tr><tr><td>商业I 2 O 5 </td><td> 719 </td><td> 5.5 </td><td> 215 </td><td> 46.5 </td><td> 0.93 </td><td> 22.6 </td></tr><tr><td>非晶I 2 O 5 </td><td> NM </td><td> NM </td><td> 1085 </td><td> 0.3 </td><td> 0.73 </td><td> 17.8 </td></tr><tr><td> HIO 3脱水</td><td> NM </td><td> NM </td><td> 393 </td><td> 12 </td><td> 0.8 </td><td> 19.3 </td></tr><tr><td>商业HIO 3 </td><td> NM </td><td> NM </td><td> NM </td><td> NM </td><td> 1.11 </td><td> 27.1 </td></tr></tbody></table> 表1火焰速度的结果。艾尔+氧化剂火焰传播速度的结果第一列表示。 NM表示无法衡量。 *表示在混合过程中我4 O 9分解成I 2 O 5。

Watch this Scientific Journal Video about Reaction Kinetics and Combustion Dynamics of I4O9 and Aluminum Mixtures at JoVE.com

Reaction Kinetics and Combustion Dynamics of I4O9 and Aluminum Mixtures

用于测量tetraiodine非氧化物（我4 O 9）和铝（Al）组成的活性混合物的火焰速度的协议提出。一种用于解决用差示扫描量热（DSC）反应动力学方法还提出。结果发现，我4 O 9为150％，比其它碘（V）的氧化物更具反应性的。

反应动力学和我燃烧动力学<sub&gt; 4</sub&gt; 0<sub&gt; 9</sub&gt;和铝的混合物

Tetraiodine nonoxide (I4O9) has been synthesized using a dry approach that combines elemental oxygen and iodine without the introduction of hydrated ...

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Reaction Kinetics and Combustion Dynamics of I4O9 and Aluminum Mixtures

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10.8K 次观看.  Texas Tech University. 用于测量tetraiodine非氧化物（我4 O 9）和铝（Al）组成的活性混合物的火焰速度的协议提出。一种用于解决用差示扫描量热（DSC）反应动力学方法还提出。结果发现，我4 O 9为150％，比其它碘（V）的氧化物更具反应性的。 

视频: Reaction Kinetics and Combustion Dynamics of I4O9 and Aluminum Mixtures

Measurement and Analysis of Atomic Hydrogen and Diatomic Molecular AlO, C2, CN, and TiO Spectra Following Laser-induced Optical Breakdown

In this work, we present time-resolved measurements of atomic and diatomic spectra following laser-induced optical breakdown. A typical LIBS arrangement is used. Here we operate a Nd:YAG laser at a frequency of 10 Hz at the fundamental wavelength of 1,064 nm. The 14 nsec pulses with anenergy of 190 mJ/pulse are focused to a 50 &#181;m spot size to generate a plasma from optical breakdown or laser ablation in air. The microplasma is imaged onto the entrance slit of a 0.6 m spectrometer, and spectra are recorded using an 1,800 grooves/mm grating an intensified linear diode array and optical multichannel analyzer (OMA) or an ICCD. Of interest are Stark-broadened atomic lines of the hydrogen Balmer series to infer electron density. We also elaborate on temperature measurements from diatomic emission spectra of aluminum monoxide (AlO), carbon (C2), cyanogen (CN), and titanium monoxide (TiO).
The experimental procedures include wavelength and sensitivity calibrations. Analysis of the recorded molecular spectra is accomplished by the fitting of data with tabulated line strengths. Furthermore, Monte-Carlo type simulations are performed to estimate the error margins. Time-resolved measurements are essential for the transient plasma commonly encountered in LIBS.

Measurement and Analysis of Atomic Hydrogen and Diatomic Molecular AlO, C2, CN, and TiO Spectra Following Laser-induced Optical Breakdown

Time-resolved atomic and diatomic molecular species are measured using LIBS. The spectra are collected at various time delays following the generation of optical breakdown plasma with Nd:YAG laser radiation&#160;and are analyzed to infer electron density and temperature.

测量和原子氢和双原子分子ALO，C分析<sub&gt; 2</sub&gt;，CN和二氧化钛光谱承接激光诱导光学击穿

In this work, we present time-resolved measurements of atomic and diatomic spectra following laser-induced optical breakdown. A typical LIBS arrangement ...

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Flame Experiments at the Advanced Light Source: New Insights into Soot Formation Processes

The following experimental protocols and the accompanying video are concerned with the flame experiments that are performed at the Chemical Dynamics Beamline of the Advanced Light Source (ALS) of the Lawrence Berkeley National Laboratory1-4. This video demonstrates how the complex chemical structures of laboratory-based model flames are analyzed using flame-sampling mass spectrometry with tunable synchrotron-generated vacuum-ultraviolet (VUV) radiation. This experimental approach combines isomer-resolving capabilities with high sensitivity and a large dynamic range5,6. The first part of the video describes experiments involving burner-stabilized, reduced-pressure (20-80 mbar) laminar premixed flames. A small hydrocarbon fuel was used for the selected flame to demonstrate the general experimental approach. It is shown how species&#8217; profiles are acquired as a function of distance from the burner surface and how the tunability of the VUV photon energy is used advantageously to identify many combustion intermediates based on their ionization energies. For example, this technique has been used to study gas-phase aspects of the soot-formation processes, and the video shows how the resonance-stabilized radicals, such as C3H3, C3H5, and i-C4H5, are identified as important intermediates7. The work has been focused on soot formation processes, and, from the chemical point of view, this process is very intriguing because chemical structures containing millions of carbon atoms are assembled from a fuel molecule possessing only a few carbon atoms in just milliseconds. The second part of the video highlights a new experiment, in which an opposed-flow diffusion flame and synchrotron-based aerosol mass spectrometry are used to study the chemical composition of the combustion-generated soot particles4. The experimental results indicate that the widely accepted H-abstraction-C2H2-addition (HACA) mechanism is not the sole molecular growth process responsible for the formation of the observed large polycyclic aromatic hydrocarbons (PAHs).

Gas sampling from laboratory-scale flames with online analysis of all species by mass spectrometry is a powerful method to investigate the complex mixture of chemical compounds occurring during combustion processes. Coupled with tunable soft ionization via synchrotron-generated vacuum-ultraviolet radiation, this technique provides isomer-resolved information and potentially fragment-free mass spectra.

火焰在实验的先进光源：全新洞察烟灰形成过程

The following experimental protocols and the accompanying video are concerned with the flame experiments that are performed at the Chemical Dynamics ...

Preparation and Reactivity of Gasless Nanostructured Energetic Materials

High-Energy Ball Milling (HEBM) is a ball milling process where a powder mixture placed in the ball mill is subjected to high-energy collisions from the balls. Among other applications, it is a versatile technique that allows for effective preparation of gasless reactive nanostructured materials with high energy density per volume (Ni+Al, Ta+C, Ti+C). The structural transformations of reactive media, which take place during HEBM, define the reaction mechanism in the produced energetic&#160;composites. Varying the processing conditions permits fine tuning of the milling-induced microstructures of the fabricated composite particles. In turn, the reactivity, i.e., self-ignition temperature, ignition delay time, as well as reaction kinetics, of high energy density materials depends on its microstructure. Analysis of the milling-induced microstructures suggests that the formation of fresh oxygen-free intimate high surface area contacts between the reagents is responsible for the enhancement of their reactivity. This manifests itself in a reduction of ignition temperature and delay time, an increased rate of chemical reaction, and an overall decrease of the effective activation energy of the reaction. The protocol provides a detailed description for the preparation of reactive nanocomposites with tailored microstructure using short-term HEBM method. It also describes a high-speed thermal imaging technique to determine the ignition/combustion characteristics of the energetic materials. The protocol can be adapted to preparation and characterization of a variety of nanostructured energetic composites.

This protocol describes the preparation of gasless nanostructured energetic materials (Ni+Al, Ta+C, Ti+C) using the short-term high-energy ball milling (HEBM) technique. It also describes a high-speed thermal imaging method to study the reactivity of mechanically fabricated nanocomposites. These protocols can be extended to other reactive nanostructured energetic materials.

准备和无气腹纳米结构的反应含能材料

High-Energy Ball Milling (HEBM) is a ball milling process where a powder mixture placed in the ball mill is subjected to high-energy collisions from the ...

Research and Development of High-performance Explosives

Developmental testing of high explosives for military applications involves small-scale formulation, safety testing, and finally detonation performance tests to verify theoretical calculations. For newly developed formulations, the process begins with small-scale mixes, thermal testing, and impact and friction sensitivity. Only then do subsequent larger scale formulations proceed to detonation testing, which will be covered in this paper. Recent advances in characterization techniques have led to unparalleled precision in the characterization of early-time evolution of detonations. The new technique of Photonic Doppler Velocimetry (PDV) for the measurement of detonation pressure will be shared and compared with traditional fiber-optic detonation velocity and plate-dent calculation of detonation pressure. In particular, the role of aluminum in explosive formulations will be discussed. Recent developments led to the development of explosive formulations that result in reaction of aluminum very early in the detonation product expansion. This enhanced reaction leads to changes in the detonation velocity and pressure due to reaction of the aluminum with oxygen in the expanding gas products.

Developmental testing of high explosives for military applications involves small-scale formulation, safety testing, and finally detonation performance tests to verify theoretical calculations. This paper will share typical development tests associated with the measurement of detonation velocity and detonation pressure.

高性能炸药的研究与发展

Developmental testing of high explosives for military applications involves small-scale formulation, safety testing, and finally detonation performance ...

Combustion Characterization and Model Fuel Development for Micro-tubular Flame-assisted Fuel Cells

Combustion based power generation has been accomplished for many years through a number of heat engine systems. Recently, a move towards small scale power generation and micro combustion as well as development in fuel cell research has created new means of power generation that combine solid oxide fuel cells with open flames and combustion exhaust. Instead of relying upon the heat of combustion, these solid oxide fuel cell systems rely on reforming of the fuel via combustion to generate syngas for electrochemical power generation. Procedures were developed to assess the combustion by-products under a wide range of conditions. While theoretical and computational procedures have been developed for assessing fuel-rich combustion exhaust in these applications, experimental techniques have also emerged. The experimental procedures often rely upon a gas chromatograph or mass spectrometer analysis of the flame and exhaust to assess the combustion process as a fuel reformer and means of heat generation. The experimental techniques developed in these areas have been applied anew for the development of the micro-tubular flame-assisted fuel cell. The protocol discussed in this work builds on past techniques to specify a procedure for characterizing fuel-rich combustion exhaust and developing a model fuel-rich combustion exhaust for use in flame-assisted fuel cell testing. The development of the procedure and its applications and limitations are discussed.

A protocol for creating a model fuel-rich combustion exhaust is developed through combustion characterization and is applied for micro-tubular flame-assisted fuel cell testing and research.

燃烧特性参数和模型燃料开发的微型管状火焰辅助燃料电池

Combustion based power generation has been accomplished for many years through a number of heat engine systems. Recently, a move towards small scale power ...

Facile Preparation of Ultrafine Aluminum Hydroxide Particles with or without Mesoporous MCM-41 in Ambient Environments

An aqueous suspension of nanogibbsite was synthesized via the titration of aluminum aqua acid [Al(H2O)6]3+ with L-arginine to pH 4.6. Since the hydrolysis of aqueous aluminum salts is known to produce a wide array of products with a wide range of size distributions, a variety of state-of-the-art instruments (i.e., 27Al/1H NMR, FTIR, ICP-OES, TEM-EDX, XPS, XRD, and BET) were used to characterize the synthesis products and identification of byproducts. The product, which was comprised of nanoparticles (10-30 nm), was isolated using gel permeation chromatography (GPC) column technique. Fourier transform infrared (FTIR) spectroscopy and powder X-ray diffraction (PXRD) identified the purified material as the gibbsite polymorph of aluminum hydroxide. The addition of inorganic salts (e.g., NaCl) induced electrostatic destabilization of the suspension, thereby agglomerating the nanoparticles to yield Al(OH)3 precipitate with large particle sizes. By utilizing the novel synthetic method described here, Al(OH)3 was partially loaded inside the highly ordered mesoporous framework of MCM-41, with average pore dimensions of 2.7 nm, producing an aluminosilicate material with both octahedral and tetrahedral Al (Oh/Td = 1.4). The total Al content, measured using energy-dispersive X-ray spectrometry (EDX), was 11% w/w with a Si/Al molar ratio of 2.9. A comparison of bulk EDX with surface X-ray photoelectron spectroscopy (XPS) elemental analysis provided insight into the distribution of Al within the aluminosilicate material. Furthermore, a higher ratio of Si/Al was observed on the external surface (3.6) as compared to the bulk (2.9). Approximations of O/Al ratios suggest a higher concentration of Al(O)3 and Al(O)4 groups near the core and external surface, respectively. The newly developed synthesis of Al-MCM-41 yields a relatively high Al content while maintaining the integrity of the ordered silica framework and can be used for applications where hydrated or anhydrous Al2O3 nanoparticles are advantageous.

An ultrafine aluminum hydroxide nanoparticle suspension was prepared via the controlled titration of [Al(H2O)]3+ with L-arginine to pH 4.6 with and without cage-effect confinement within mesoporous channels of MCM-41.

在环境环境中制备具有或不具有介孔MCM-41的超细氢氧化铝颗粒

An aqueous suspension of nanogibbsite was synthesized via the titration of aluminum aqua acid [Al(H2O)6]3+ with L-arginine to pH 4.6. Since the hydrolysis ...

化学

Nanothermite with Meringue-like Morphology: From Loose Powder to Ultra-porous Objects

The goal of the protocol described in this article is to prepare aluminothermic compositions (nanothermites) in the form of porous, monolithic objects. Nanothermites are combustible materials made up of inorganic fuel and an oxidizer. In nanothermite foams, aluminum is the fuel and aluminum phosphate and tungsten trioxide are the oxidizing moieties. The highest flame propagation velocities (FPVs) in nanothermites are observed in loose powders and FPVs are strongly decreased by pelletizing nanothermite powders. From a physical standpoint, nanothermite loose powders are metastable systems. Their properties can be altered by unintentional compaction induced by shocks or vibrations or by the segregation of particles over time by settling phenomena, which originates from the density differences of their components. Moving from a powder to an object is the challenge that must be overcome to integrate nanothermites in pyrotechnic systems. Nanothermite objects must have both a high open porosity and good mechanical strength. Nanothermite foams meet both of these criteria, and they are prepared by dispersing a nano-sized aluminothermic mixture (Al/WO3) in orthophosphoric acid. The reaction of aluminum with the acid solution gives the AlPO4 &#34;cement&#34; in which Al and WO3 nanoparticles are embedded. In nanothermite foams, aluminum phosphate plays the dual role of binder and oxidizer. This method can be used with tungsten trioxide, which is not altered by the preparation process. It could probably be extended to some oxides, which are commonly used for the preparation of high performance nanothermites. The WO3-based nanothermite foams described in this article are particularly insensitive to impact and friction, which makes them far safer to handle than loose Al/WO3 powder. The fast combustion of these materials has interesting applications in pyrotechnic igniters. Their use in detonators as primers would require the incorporation of a secondary explosive in their composition.

This manuscript describes the synthesis of combustible aluminophosphate matrices by the reaction of orthophosphoric acid (H3PO4) with aluminum nanopowder. When this reaction is carried out with excess aluminum in the presence of tungsten trioxide nanopowder, it leads to a solid, porous nanothermite foam.

Nanothermite 与蛋白酥样形态学: 从松散的粉末到超多孔物体

The goal of the protocol described in this article is to prepare aluminothermic compositions (nanothermites) in the form of porous, monolithic objects. ...

Combustion Chemistry of Fuels: Quantitative Speciation Data Obtained from an Atmospheric High-temperature Flow Reactor with Coupled Molecular-beam Mass Spectrometer

This manuscript describes a high-temperature flow reactor experiment coupled to the powerful molecular beam mass spectrometry (MBMS) technique. This flexible tool offers a detailed observation of chemical gas-phase kinetics in reacting flows under well-controlled conditions. The vast range of operating conditions available in a laminar flow reactor enables access to extraordinary combustion applications that are typically not achievable by flame experiments. These include rich conditions at high temperatures relevant for gasification processes, the peroxy chemistry governing the low temperature oxidation regime or investigations of complex technical fuels. The presented setup allows measurements of quantitative speciation data for reaction model validation of combustion, gasification and pyrolysis processes, while enabling a systematic general understanding of the reaction chemistry. Validation of kinetic reaction models is generally performed by investigating combustion processes of pure compounds. The flow reactor has been enhanced to be suitable for technical fuels (e.g. multi-component mixtures like Jet A-1) to allow for phenomenological analysis of occurring combustion intermediates like soot precursors or pollutants. The controlled and comparable boundary conditions provided by the experimental design allow for predictions of pollutant formation tendencies. Cold reactants are fed premixed into the reactor that are highly diluted (in around 99 vol% in Ar) in order to suppress self-sustaining combustion reactions. The laminar flowing reactant mixture passes through a known temperature field, while the gas composition is determined at the reactors exhaust as a function of the oven temperature. The flow reactor is operated at atmospheric pressures with temperatures up to 1,800 K. The measurements themselves are performed by decreasing the temperature monotonically at a rate of -200 K/h. With the sensitive MBMS technique, detailed speciation data is acquired and quantified for almost all chemical species in the reactive process, including radical species.

An investigation of the oxidative combustion chemistry of novel biofuels, fuel components, or jet fuels by comparison of quantitative speciation data is presented. The data can be used for kinetic model validation and enables fuel assessment strategies.This manuscript describes the atmospheric high-temperature flow reactor and demonstrates its capabilities.

燃料燃烧化学: 用耦合分子束质谱仪从大气高温流反应器中获得的定量形态数据

This manuscript describes a high-temperature flow reactor experiment coupled to the powerful molecular beam mass spectrometry (MBMS) technique. This ...

Identification and Quantification of Decomposition Mechanisms in Lithium-Ion Batteries; Input to Heat Flow Simulation for Modeling Thermal Runaway

The risks and possible accidents related to the normal use of lithium-ion batteries remain a serious concern. In order to get a better understanding of thermal runaway (TR), the exothermic decomposition reactions in anode and cathode were studied, using a Simultaneous Thermal Analysis (STA)/Gas Chromatography-Mass Spectrometry (GC-MS)/Fourier Transform Infrared (FTIR) spectrometer system. These techniques allowed the identification of the reaction mechanisms in each electrode, owing to the analysis of evolved gaseous species, the amount of heat released and mass loss. These results provided insight into the thermal events happening within a broader temperature range than covered in previously published models. This allowed the formulation of an improved thermal model to depict TR. The heat of reaction, activation energy, and frequency factor (thermal triplets) for each major exothermic process at material level were investigated in a Lithium Nickel-Manganese-Cobalt-Oxide (NMC (111))-Graphite battery cell. The results were analyzed, and their kinetics were derived. These data can be used to successfully simulate the experimental heat flow.

This work aims at determining the reaction kinetics of Li-ion battery cathode and anode materials undergoing thermal runaway (TR). Simultaneous Thermal Analysis (STA)/Fourier Transform Infrared (FTIR) spectrometer/Gas Chromatography Mass Spectrometry (GC-MS) were used to reveal thermal events and to detect evolved gases.

锂离子电池分解机理的鉴定和量化;用于模拟热失控的热流仿真输入

The risks and possible accidents related to the normal use of lithium-ion batteries remain a serious concern. In order to get a better understanding of ...

Metal Oxide Heterojunction for Photocatalytic Activities

There is a significant global demand for improvements in synthesis techniques and their optimal characteristics, especially for industrial-scale applications. Sol-gel-based solution combustion synthesis (SG-SCS) is a simple method to produce ordered porous materials. In this regard, Pearson&#39;s hard and soft acids and bases theory assists in selecting host-dopant reactivity to form a proper heterojunction.
The formation of a heterojunction also changes the essential properties of the materials, improving photocatalysis via charge transfer or synergistic activities. A calcination temperature of 500 &#176;C is ideal for this process based on the results of the stability assessment via a differential thermogravimetry ratio analysis (DTG).
The nanoscale dimensions of the nanoparticles (NPs) and nanocomposites (NCs) generated were validated using X-ray diffraction and high-resolution transmission electron microscopy (HRTEM). Furthermore, the scanning electron microscopy micrographs and BET analyses confirmed the porosity nature of the materials. HRTEM, X-ray photoelectron spectroscopy, and energy-dispersive X-ray investigations established the materials composition. The study found that NCs degraded the acid orange 8 (AO8) color more efficiently than bare ZnO.

The development of a heterojunction boosts the photocatalytic activities of solution combustion synthesis, which is a time-/energy-efficient process. Advanced analytical characterization techniques were used in this protocol to evaluate the materials&#39; characteristics, and nanocomposites demonstrated improved acid orange-8 dye degradation.

反应动力学和我燃烧动力学

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测量和原子氢和双原子分子ALO，C分析