Non-thermal Plasma Activated Water for Increasing Germination and Plant Growth of Lactuca sativa L

Plasma Chemistry and Plasma Processing - Non-thermal plasma is widely considered as an effective technology for applications in agriculture. Particularly, numerous reports studies have highlighted...     

种子萌发生长的微量热及非平衡热力学研究

生命系统中发生的许多过程都有放热和吸热现象.人们对于生命过程的热现象进行了很多研究.对于植物生长的能量效应研究也做了一些工作[1—4].种子萌发生长的热释出是植物产热的一个很好例子,在种子萌发生长过程中伴随着物质和能量的转化,用微量热法测定种子萌发生长热谱并解析这些热谱,将有助于我们认识种子萌发生长机理及其影响因素.Ｐｒａｔ等人曾对小麦、玉米及一些蔬菜种子的萌发生长进行过较为系统的研究[1,2].他们的工作为用量热法研究植物产热开辟了道路.但由于当时测量技术与仪器设计的限制,其研究结果是粗糙的,且与种子萌发的实际情…     

Seed Germination and Early Growth Responses to Seed Pre-treatment by Non-thermal Plasma in Hemp Cultivars (<Emphasis Type="Italic">Cannabis sativa</Emphasis> L.)

The two key questions addressed in this paper were whether different cultivars of hemp (Cannabis sativa L.) have the same reactions to non-thermal plasma seed pre-treatments and whether different plasma sources have different effects on the seeds. Seed germination and early growth of hemp in design of hierarchical analysis of variance was conducted. Differences in response among seeds of three hemp cultivars (‘Finola’, ‘Bialobrzeskie’, ‘Carmagnola’) to the non-thermal plasma pre-treatment generated by two apparatuses (gliding arc and downstream microwave devices) in four time expositions (0, 180, 300, 600 s) were found. The high importance was found in type of apparatus and time exposition. A positive/neutral effect was observed in all measured characteristics after gliding arc plasma pre-treatment. Gliding arc pre-treatment increased the length of seedlings, seedling accretion and weight of seedling in both cv. ‘Finola’ and cv. ‘Bialobrzeskie’ hemp. On the other hand, the downstream microwave apparatus had an inhibiting effect on all tested hemp cultivars. It was the first time when significant differences in response to non-thermal pre-treatment were found in taxonomically close plants. The results obtained in this study describes different effect of various plasma treatment on germination and early growth of hemp seeds. The direct pre-treatment of non-thermal plasma discharge in condition of atmospheric pressure was better. Results of our experiment show that the use of non-thermal plasma pre-treatment may increase survival of some hemp cultivars during seedlings establishment in a drier period and may be used in new agro-technical measures in unconventional agriculture.     

Treatment of Pea Seeds with Plasma Activated Water to Enhance Germination,Plant Growth,and Plant Composition

Plasma Chemistry and Plasma Processing - The present study has been carried to investigate the interaction and effect of plasma activated water (PAW) on pea seeds. PAW is produced with the...     

The Roles of Various Plasma Active Species in Toluene Degradation by Non-thermal Plasma and Plasma Catalysis

Plasma Chemistry and Plasma Processing - Investigating the roles of plasma active species in plasma chemical reaction process can improve understanding of the mechanism of volatile organic...     

Cold Atmospheric Pressure Nitrogen Plasma Jet for Enhancement Germination of Wheat Seeds

Plasma Chemistry and Plasma Processing - The possibility to improve the germination characterization of the wheat seeds by cold atmospheric nitrogen plasma jet treatment was report. Spectroscopic...     

低温等离子体与天然丝光沸石协同降解正己醛

本文研究了在低温等离子体和天然丝光沸石(Natural Mordenite,NMOR)的共同作用下对低浓度正己醛的降解性能。研究结果表明,在降解低浓度正己醛的反应中,低温等离子体与天然丝光沸石之间能产生很好的催化协同作用,当放电功率为2.8W时,反应温度为80℃时,干燥空气气氛下,天然丝光沸石对1 200 mL.m-3正己醛的去除率为93.9%;另外天然丝光沸石经酸处理后,这种协同作用可以进一步提高,正己醛的去除率达到96.5%;天然沸石的结构性能稳定,在实验条件下,天然沸石连续使用55 h,催化活性未见下降。     

Direct Non-oxidative Methane Conversion by Non-thermal Plasma: Modeling Study

The direct non-oxidative conversion of methane to higher hydrocarbons in dielectric barrier discharges has been investigated theoretically at atmospheric pressure. Preliminary modeling of the results is presented, based on a well-stirred reactor model to determine the spatially and time-averaged species composition through the solution of balance equations for species, mass, gas and electron energy. The results show good quantitative agreement between model predications and experimental measurements by considering the glow and after-glow regions. Moreover, the model has predicted that there exists a transition where the main product of ethane will transform to acetylene by increasing the specific energy. The dominant reaction paths and the possibility of selective to C₂ hydrocarbons have been discussed. A list of gas-phase reactions has been compiled for modeling methane conversion in non-thermal plasma and can be employed in more sophisticated two- or three-dimensional plasma simulations.     

Direct Non-oxidative Methane Conversion by Non-thermal Plasma: Experimental Study

The direct non-oxidative conversion of methane to higher hydrocarbons in non-thermal plasma, namely dielectric barrier discharge and corona discharge, has been investigated experimentally at atmospheric pressure. In dielectric barrier discharge, the methane is mainly converted to ethane and propane with small amounts of unsaturated and higher hydrocarbons. While in corona discharge, methane was activated mainly to acetylene with small amount of other higher hydrocarbons. Decreasing the gas flow or increasing power input will improve the methane conversion and product yields. It is found that the methane conversion and main product yield against the input specific energy were special functions in both dielectric barrier discharge and corona discharge, independent of the reactor size, and whether fixing flow rate or power input and changing the power input or flow rate. The corona discharge is a promising alternative method for methane conversion to produce acetylene and hydrogen at low temperature.     

Mechanisms of Xylene Isomer Oxidation by Non-thermal Plasma via Paired Experiments and Simulations

Xylene is a widely used solvent and industrial chemical, but it is also considered to be a volatile organic compound (VOC) pollutant. Meanwhile, non-thermal plasma (NTP) is a potential method for remediating VOC contaminants, especially aromatic hydrocarbons. During NTP degradation of xylene, the different oxidation mechanisms of three isomers, p-xylene, o-xylene and m-xylene, have attracted lots of attention but not been studied at the molecular level. In this study, the individual degradation rates of xylene isomers in a NTP system are measured. The results show the oxidation degradation rates have the following order: o-xylene?>?p-xylene?≈?m-xylene. Molecular dynamics simulations with an applied external electric field were adopted to examine the oxidation process of xylene isomers, as well. The oxidation rates from the simulations were calculated, the order of which is in a good agreement with the experimental results. The oxidation pathways of xylene isomers were analyzed more thoroughly to explain the rate differences. The external electrical field is found to have two effects: one is to speed up the oxidation rate of xylene isomers overall, and the other is to alter the oxidation pathways to increase the probability of the faster ring cleavage pathways of o-xylene.

     

Experimental Study on Purification of Diesel Particulate Matter by Non-thermal Plasma Technology

In order to investigate the effects of non-thermal plasma (NTP) on diesel particulate matter (PM), an engine test bench was built up. An engine exhaust particle sizer (EEPS) was introduced to analyze the emission concentration and size distribution of PM and a thermo-gravimetric analyzer was used to analyze the effects of NTP on the composition of the particulate matter in the exhaust gas. The results show that the size distribution interval of the particle mass concentration falls behind that of the quantity concentration under various loads. When the diesel engine operating speed is 2400 rpm and the load is 25%, after NTP, the proportions of the nucleation mode particles and the accumulative mode particles exhibit a small fluctuation while the proportion of ultrafine particles decreases by 10% due to their large quantity concentration. Under the dual effect of DPF and NTP, the particle quantity concentration decreases by 98%. In order to investigate the effect of NTP on the composition of the PM, a thermo-gravimetric analysis of the particles obtained before and after NTP was carried out. The results show that the proportion of volatile matter falls by 16.05% and solid carbon accounts for an increase of 7.29%. NTP has the ability to improve reduction activity of particles and make particles easier to be oxidized at a lower temperature.     

Inactivation of Bacteria in Oil Field Injection Water by Non-thermal Plasma Treatment

Microbial pollution commonly causes serious pipe corrosion in oil field injection water system. This paper reports on the application of non-thermal plasma to inactivate bacteria in oil filed injection water. As an efficient inactivation technology, pulsed streamer discharge plasma method injects energy into solution through a plasma channel formed by discharge between electrodes and produces various active species in solution with physical effects (electric field, UV etc.) occurring. Saprophytic bacteria, iron bacteria and sulfate reducing bacteria are used as target. The effects of various gases bubbling (oxygen, nitrogen and air) as well as aeration intensity are investigated. Experimental results show that the inactivation efficiency is greatly enhanced by gas bubbling. After 150 s discharge with oxygen bubbling (667 m³ (m³ h)^?1), the inactivation efficiencies of saprophytic bacteria, iron bacteria and sulfate reducing bacteria achieve 1.85, 4.51 and 5.70 log reduction, respectively. The possible mechanism of bacteria inactivation is also discussed.     

Removal of Hexanal by Non-thermal Plasma and MnOx/y-Al2O3 Combination

研究了在低温等离子体和催化剂共同作用下低浓度正己醛的降解反应.结果表明,等离子体与γ-Al2O3之间产生了很好的催化协同作用,在低放电功率(2.8W)和低温(80 ℃)下,干燥空气气氛中,γ-Al2O3对0.12％正己醛的去除率为87.1％;当γ-Al2O3负载7.5％MnOx后,正己醛去除率达到96.5％,其效果与Pt/γ-Al2O3相当.7.5％MnOx/γ-Al2O3在实验条件下连续使用50h,其催化活性未见下降.     

低温等离子体处理化工恶臭污染物硫化氢的研究

采用电晕放电低温等离子体处理模拟硫化氢恶臭气体,考察了输入功率、初始浓度、气体湿度、停留时间等因素对降解效果和能量效率的影响,同时对反应过程进行了动力学研究。研究表明：输入功率以及停留时间对硫化氢降解的影响是积极的,但能量效率随着两者的增加先增大后减小。硫化氢的降解率随着初始浓度的增加而降低,而能量效率随着初始浓度的增加而增加。在气体湿度增加初期,硫化氢降解率和能量效率均随着气体湿度的增加而增加,当气体湿度为50%时达到最大值,然而随着气体湿度的进一步增加,其降解率和能量效率反而降低。对电晕放电低温等离子体处理硫化氢的反应动力学进行了分析,得到硫化氢的反应速率常数为kH2S=0.356 8 m3/（W·h）。     

Graphitization of Carbon Particles in a Non-thermal Plasma Reactor

The production of nanomaterials using non-thermal plasmas remains the focus of ongoing investigations due to advantageous properties of this class of processes, most notably the intense plasma-induced heating arising from energetic recombination events occurring at the surface of nanoparticles, which allows for the tailored synthesis of crystalline nanoparticles. In this work, the authors discuss an in situ, in-flight Fourier Transform Infrared absorption spectroscopy technique to investigate the temperature variation of carbon nanoparticles during their synthesis in an acetylene–argon–hydrogen non-thermal RF plasma. Based on the FTIR measurements, decreasing hydrogenation levels and the progressive onset of an incandescence signal were observed at increasing RF input power. In the high RF power region, the carbon particle temperature, derived by fitting the corresponding FTIR spectra with a modified Planck’s law, shows values above 2000 K. The corresponding ex situ characterization of the synthesized materials by Transmission Electron Microscopy and Raman Spectroscopy displays the production of highly graphitic particles and loss of bonded hydrogen from the material, hence supporting the substantial nanoparticle heating derived from the FTIR measurements.     

电晕放电式低温等离子体电极结构优化

以恶臭气体氨气和硫化氢的降解率为考察指标,系统优化了电晕放电式低温等离子体设备电极间距、电极齿距、电极齿高三个参数。研究表明:氨气和硫化氢的降解首先随着电极间距和齿距的增加而增大,而后随着电极间距的进一步增大而逐渐降低,电极间距13 mm、电极齿距5 mm时具有最大的氨气和硫化氢降解率。当电极齿高7 mm时,氨气和硫化氢的降解率随电极齿高的增加而快速增大,当电极齿高7 mm时,其降解率随着电极齿高的进一步增大而缓慢增大,考虑到电极制作成本,故确定最佳电极齿高为7 mm。此外研究还表明,不同外施功率下,锯齿型(多齿型)的氨气降解率显著高于单一针尖型(单齿型)。     

等离子体与催化剂协同催化CH4选择性还原脱硝反应

研究了在低温等离子体和催化剂共同作用下,CH4选择催化还原(SCR)NO的反应.在所考察的金属氧化物催化剂中,γ-Al2O3表现出最高的催化活性.当等离子体放电功率为4.5 W,反应温度为300℃时,NO转化率为56.5％;该条件下单纯等离子体反应和以γ-Al2O3为催化剂时NO转化率分别为28.9％和0,表明等离子体...     

Improvement of the Diluted Propane Efficiency Treatment Using a Non-thermal Plasma

The decomposition of propane diluted in air has been investigated using a pulsed high-voltage dielectric barrier discharges reactor. Effects of the temperature (from 300 to 800 K) and humidity in air on propane conversion and on produced species are studied. CO and CO₂ are the two main carbon species produced but other carbon species can be also obtained as functions of electrical parameters or temperature. Total decomposition of inlet propane to CO₂ is possible when propane is diluted in wet air from 600 K. Thermal energy is an important parameter to limit the energy density injected in the plasma reactor and to reduce the total energetic cost keeping a high propane decomposition yield.     

Chemical Composition and Lignins of Tomato and Pomegranate Seeds

Tomato and pomegranate seeds were analyzed quantitatively. Lignin hydrochloride was isolated from their seeds and characterized. Lignocarbohydrate complexes were isolated by base hydrolysis. Their elemental composition, IR spectra, and molecular weights were determined.     

Air Atmospheric Dielectric Barrier Discharge Plasma Induced Germination and Growth Enhancement of Wheat Seed

Air atmospheric dielectric barrier discharge plasma (DBD) was attempted to pretreat wheat seed to improve its germination and growth in this study. The effects of the DBD plasma treatment on the wheat seed germination, seedling growth, osmotic-adjustment products, lipid peroxidation level, and antioxidant enzymes activity were investigated. The experimental results showed that the DBD plasma treatment with an appropriate time scale could promote the wheat seed germination and seedling growth. The germination potential, germination rate, germination index, and vigor index increased by 26.7, 9.1, 16.9, and 46.9% after 7 min’s DBD plasma treatment, respectively; the root length, shoot length, fresh weight, and dry weight of the seedlings also increased after the DBD plasma treatment. The osmotic-adjustment products, proline and soluble sugar contents, in the wheat seedlings were significantly enhanced after the DBD plasma treatment with an appropriate time scale, while the malondialdehyde content decreased. Moreover, the activities of superoxide dismutase and peroxidase also increased after the DBD plasma treatment. The DBD plasma treatment led to etching effect on the wheat seed coat, resulting in the improvement of its water absorption capacity.