Gas–liquid flow mass transfer in a T-shape microreactor stimulated with 1.7 MHz ultrasound waves

This paper describes the application of ultrasound waves on hydrodynamics and mass transfer characteristics in the gas–liquid flow in a T-shape microreactor with a diameter of 800 μm. A 1.7 MHz piezoelectric transducer(PZT) was employed to induce the vibration in this microreactor. Liquid side volumetric mass transfer coefficients were measured by physical and chemical methods of CO_2 absorption into water and Na OH solution. The approach of absorption of CO_2 into a 1 mol·L^(-1) Na OH solution was used for analysis of interfacial areas. With the help of a photography system, the fluid flow patterns inside the microreactor were analyzed. The effects of superficial liquid velocity, initial concentration of Na OH, superficial CO_2 gas velocity and length of microreactor on the mass transfer rate were investigated. The comparison between sonicated and plain microreactors(microreactor with and without ultrasound) shows that the ultrasound wave irradiation has a significant effect on kLa and interfacial area at various operational conditions. For the microreactor length of 12 cm, ultrasound waves improved kLa and interfacial area about 21% and 22%, respectively. From this study, it can be concluded that ultrasound wave irradiation in microreactor has a great effect on the mass transfer rate. This study suggests a new enhancement technique to establish high interfacial area and kLa in microreactors.

Gas-liquid-liquid extraction in a novel rotating microchannel extractor

In this work,a novel rotating microchannel extractor(RME)is designed and further used for the extraction of chromium(Ⅲ)from water.Unexpectedly,the micro-extraction had the same effect as carrying out 2.9-stage cross-flow extractions.Various factors,including the gas intake methods,gas intake quantity(Qg),distance between inner rotor and outer wall(D),rotational inner rotor speed(R)and volumetric flow rate(Qa,Qo),were selected to investigate their effect on the extraction efficiency(η)thoroughly.The relation map ofηwith Weaand We(o-g)for RME provides a comprehension for the gas–liquid–liquid extraction process in this RME system.

Exploring Chemovar-Specific Cannabis Extracts Quantification and Evaluation of Cytotoxic Compounds for Targeting Glioblastoma Multiforme

Glioblastoma Multiforme (GBM) represents one of the most aggressive and metastatic brain tumors, with a dismal success rate of less than three percent after five years, particularly in tumors with active immune checkpoints. This necessitates the development of targeted endogenous agents for precise GBM treatment. Previous experiments utilizing Chemovar Specific Cannabis Extractions (CSCEs), fractionated with polar solvents and quantified using Liquid and Gas Column Chromatography combined with Mass Spectrometry (LC/GCMS), have shown reduced viability and motility in human GBM cell lines. However, the complexity of the botanical substance has hindered the personalization of standard cannabis medicines for GBM due to unknown synergistic effects of multiple compounds. To address this limitation, our study focuses on exposing AM251 cells to chemovar fractions extracted using a non-polar solvent, thereby isolating a broader spectrum of constituents. By employing LC/GCMS in conjunction with Nuclear Magnetic Resonance (NMR), we have identified and quantified nine* compounds present in the non-polar CSCE that exhibit significant efficacy (0.1 μM) in inducing cytotoxicity* in GBM tumor cells. Conversely, the polar fraction in our experiment did not demonstrate efficacy against UM251 cells. The quantification of individual compounds within a cannabis extraction that selectively induces cell death in brain tumors holds promise for guiding future research and facilitating the development of a standardized CSCE for GBM therapy.

STUDY OF DOWNFLOW LIQUID JET LOOP REACTOR

1 INTRODUCTIONLiquid jet loop reactor(JLR)may be upflow(U-JLR)or downflow reactors(D-JLR)in design.The major differences between the two are the location of the nozzle andthe direction of the fluid flow.A large number of investigations on U-JLR havebeen published,but D-JLR with nozzles positioned on the top portion of the reac-tor was not much studied until recently.Up to now,only a few experimentalstudies on the hydrodynamics and mass transfer of D-JLR have been carried out[1-4].

Phytochemical constituents,antioxidant and antibacterial activities of methanolic extract of Ardisia elliptica

Objective:To investigate the antioxidant,antibacterial,and chemical ingredients of Ardisia elliptica(A.elliptica) methanolic extracts.Methods:The plant was extracted using methanol.Antibacterial and antioxidant activities were evaluated.Results:The results showed that both fruit and leaf extract of A.elliptica have significant antibacterial activities against Gram-positive and Gram-negative bacteria.Fruit extracts showed higher content of phenolic(71 ± 0.03 GAE/mg extract dry weight),in comparison to the leaf extracts(37 ± 0.05 GAE/mg extract dry weight).Flavonoid content,and Fe2+chelating activity of fruit extracts were higher than leaf extract.The percentage radical inhibition of fruit extract is found to be higher(70%) than that of leaf extract(60%).LCMS results indicated that the major compounds in the fruit extract were Gingerol,Aspidin,Kampherol,and Stercuresin,while the leaf extract contained Gingerol,Aspidin,Triangularin,and Salicyl acyl glucuronide.Furthermore,the results of GCMS indicated that fruit extract contained these major compounds:Vitamin E Tocopherol,5-hepylresornicol,2-Nonylmalonic acid,5-pentadecylresornicol,and Stigmasta-7-22-dien-3-ol.However,leaf extract of A.elliptica contained these major compounds:Alpha Amyrenol,4,4,6,6a,6b,8,8a,9,10,11,12,12 a,14,14 a,14 b octadehydro-2H-picen-3-one,and Lonasterol,4-t-Butyl-2-[4-nitrophenyl] phenol.Conclusions:The results provide evidence that fruit and leaf of A.elliptica extracts might indeed be used as a potential source of effective natural antimicrobial and antioxidant agents in pharmaceutical and food industries.

Carbon isotopic fractionation during vaporization of low molecular weight hydrocarbons(C6–C12)

Three series of laboratory vaporization experiments were conducted to investigate the carbon isotope fractionation of low molecular weight hydrocarbons（LMWHs）during their progressive vaporization.In addition to the analysis of a synthetic oil mixture,individual compounds were also studied either as pure single phases or mixed with soil.This allowed influences of mixing effects and diffusion though soil on the fractionation to be elucidated.The LMWHs volatilized in two broad behavior patterns that depended on their molecular weight and boiling point.Vaporization significantly enriched the ^13C present in the remaining components of the C6–C9 fraction,indicating that the vaporization is mainly kinetically controlled;the observed variations could be described with a Rayleigh fractionation model.In contrast,the heavier compounds（n-C10–n-C12）showed less mass loss and almost no significant isotopic fractionation during vaporization,indicating that the isotope characteristics remained sufficiently constant for these hydrocarbons to be used to identify the source of an oil sample,e.g.,the specific oil field or the origin of a spill.Furthermore,comparative studies suggested that matrix effects should be considered when the carbon isotope ratios of hydrocarbons are applied in the field.

Numerical Study on the Effects of Contraction Ratio in a Two-Phase Flow Injection Nozzle

The Euler-Euler numerical method was used to investigate the effects of contraction ratio on twophase flow mixing with mass transfer in the flow injection nozzle. The geometric shape of the nozzle was modified to improve carbonation efficiency. A gas inlet hole was created to increase the flow mixing of CO2 with water. A nozzle throat was also introduced to increase the gas dissolution by increasing flow rates. Various contraction ratios of nozzle throat, inlet gas and liquid velocities, and gas bubble sizes were employed to determine their effects on gas hold-up, gas concentration, and mass transfer coefficient. Results revealed that the flow injection nozzle with high contraction ratios improved carbonation because of high gas hold-up. Gas concentration was directly related to contraction ratio and gas flow velocities. Carbonation reduced when high liquid velocities and large gas bubbles were employed because of inefficient flow mixing. This study indicated that flow injection nozzle with large contraction ratios were suitable for carbonation because of their ability to increase gas hold-up, gas concentration, and mass transfer coefficient.

Gas Absorption and Mass Transfer in a Pore-Array Intensified Tube-in-Tube Microchannel

A pore-array intensified tube-in-tube microchannel(PA-TMC),which is characterized by high throughput and low pressure drop,was developed as a gas–liquid contactor.The sulfite oxidation method was used to determine the oxygen efficiency(φ)and volumetric mass transfer coefficient(k_(L)a)of PA-TMC,and the mass transfer amount per unit energy(ε)was calculated by using the pressure drop.The effects of structural and operating parameters were investigated systematically,and the twophase flow behavior was monitored by using a charge-coupled device imaging system.The results indicated that the gas absorption efficiency and mass transfer performance of the PA-TMC were improved with increasing pore number,flow rate,and number of helical coil turns and decreasing pore size,row number,annular size,annular length,and surface tension.Theφ,εand k La of PA-TMC could reach 31.3%,1.73×10^(-4) mol/J,and 7.0 s-1,respectively.The Sherwood number was correlated with the investigated parameters to guide the design of PA-TMC in gas absorption and mass transfer processes.

大跨度桥梁超低频调谐液体质量阻尼器研发及应用

大跨度桥梁在运营过程中易发生较为明显的超低频振动问题,采用调谐质量阻尼器(TMD)进行控制时,由于箱梁内部空间有限,常规TMD在结构上无法满足要求。基于此,提出一种基于浮力和流固耦合作用的超低频调谐液体质量阻尼器(TLMD)。为研究TLMD对结构的阻尼减振效果,进行模型试验,分析安装TLMD前、后主结构加速度幅值和阻尼比;将该新型超低频TLMD在贵州龙里河大桥上进行实桥应用,测试主梁频率特性和阻尼比。模型试验及实桥应用结果表明:TLMD减振技术可实现0.283 Hz乃至更低频率的超低频阻尼减振;采取TLMD控制后,模型试验主结构的阻尼比从0.038%提高至2.2%,主结构的加速度幅值从减振前的0.41 m/s2降低至0.01 m/s2;贵州龙里河大桥超低频TLMD当采用0.31%的质量比时,主梁一阶竖弯模态实测阻尼比从0.20%提高至0.82%,阻尼比提高了3.1倍。超低频TLMD参数稳定、性能可靠,有效降低了阻尼器的安装高度,显著提升了结构阻尼比,增强了桥梁的抗风性能。

基于鼓泡-引射耦合的柴油初次雾化

针对斯特林发动机小负荷燃油雾化不良问题,提出了基于鼓泡-引射耦合的雾化方式.基于VOF(Volume of Fluid)仿真研究了鼓泡喷嘴内气液流态,并依据时间线性稳定性分析,对射流液膜失稳和破碎进行数学描述,建立了鼓泡-引射耦合下的初次雾化模型.分析了气液质量比RGL(gas-liquid mass ratio)、负荷对初次雾化的影响,并与传统雾化方式比较.结果表明:增大RGL会促进射流失稳、减小液滴粒径.相较于传统雾化方式,鼓泡-引射耦合下小负荷索特平均直径SMD减小约62%,雾化质量显著提高.

液相色谱-稳定同位素比值质谱法测定针叶樱桃粉中抗坏血酸的碳稳定同位素比值

该文建立液相色谱-稳定同位素比值质谱联用(liquid chromatography-stable isotope ratio mass spectrometry,LC-IRMS)检测抗坏血酸δ^(13)C值的分析方法,用于鉴别针叶樱桃粉中抗坏血酸天然来源的真实性。样品中抗坏血酸经液相色谱在线分离纯化,优化后色谱条件为:Syncronis C18(250 mm×4.6 mm,5μm)色谱柱,流动相为水-pH 2的硫酸溶液(90∶10,体积比),流速0.250 mL/min,色谱柱温度30℃,进样量10μL,通过LC-IsoLink实现目标物全部氧化为CO_(2)气体,最终以气态形式进入稳定同位素质谱仪,直接检测样品中抗坏血酸的δ^(13)C,该方法结果稳定、准确。分别测定了7个合成来源的维生素C片和19个针叶樱桃粉,结果表明,天然来源抗坏血酸δ^(13)C值为-25.00‰~-22.01‰,合成来源抗坏血酸δ^(13)C值为-11.74‰~-10.28‰,两者分布显著性差异,该方法可用于抗坏血酸产品标识的真实性鉴别研究。

Research and development of advanced structured packing in a rotating packed bed

As the core component of the rotating packing bed,packing is a place for efficient gas–liquid mixing and mass transfer.In this paper,a 3D structured packing composed of a mesh structure and a support structure was designed.The mesh structure is a ring-shaped mesh surrounded by triangular meshes,which is stable in structure and can achieve a high degree of dispersion and aggregation of the liquid phase.The support structure is composed of ring-shaped structural units arranged at a certain angle along the axial direction,which can enhance the turbulence of the airflow while constructing regular gas-phase channels.Circumferential steel meshes of different diameters and supporting structures are alternately combined to form 3D packing,which is loaded in a layered cross-flow rotating packing bed.The results show that under the same operating conditions,the mass transfer performance of 3D packing and wire mesh packing are equivalent,and both are better than pall ring packing.Moreover,the pressure drop of 3D packing is significantly lower than that of pall ring packing and wire mesh packing.The design and implementation of packing the development presented in this paper can be used to develop special structured packing for rotating bed,which can further improve the performance of rotating packed bed(RPB).

A Preliminary Gas Chromatography‑Mass Spectrometry‑Based Metabolomics Study of Rats Ingested Diazepam or Clonazepam

Drug-facilitated sexual assault(DFSA)is a sexual act in which the victim is unable to give or rescind consent due to alcohol or drug intoxication,which involved the abuse of benzodiazepines around the world.Conventional techniques used for the analysis of benzodiazepines have the limitation of short detection time window due to the rapid metabolism of these drugs in body.This study aimed to investigate the characteristic changes of metabolites in the blood of rats after ingesting diazepam/clonazepam through a gas chromatography-mass spectrometry-based metabolomics method,allowing the indirect reveal of the rats ingested diazepam/clonazepam.First,we found that diazepam and clonazepam in the blood of rats could not be detected by liquid chromatography-tandem mass spectrometry after 48 h of ingestion.Then,orthogonal partial least squares discrimination analysis regression models were,respectively,constructed to determine whether the rats ingested diazepam/clonazepam after 48 h.The results showed that 5 metabolites were found to be associated with diazepam exposure,and 7 metabolites were found to be associated with clonazepam exposure,which may be characterization for the evaluation of digestion of diazepam and clonazepam in rat.

反应温度和固液质量比对磷石膏脱水转晶的影响

为提高磷石膏的利用率和附加值,利用磷石膏在20%NaCl溶液中脱水转晶制备α-半水石膏,研究了反应温度和固液质量比对磷石膏脱水行为、转晶效率、矿相组成和微观形貌的影响。结果表明,当反应温度为80~95℃时,随着温度的升高,磷石膏的转晶速率加快,α-半水石膏的诱导成核时间和晶体生长时间均逐渐减少,总转化时间缩短。过低或过高的固液质量比均会影响磷石膏在盐溶液中的分散程度,在一定程度上阻碍磷石膏的脱水转晶,导致α-半水磷石膏的转晶时间随着固液质量比的减小呈现先减小后增大的变化趋势。在反应温度为90℃和固液质量比为1∶4的20%NaCl溶液中,磷石膏仅需常压水热反应1.34 h即可完全脱水形成长棒状α-半水石膏。

直射式气动雾化喷嘴对燃烧室性能的影响

为了深入分析燃油喷嘴对燃气轮机燃烧室性能的影响,针对燃气轮机燃烧室中的直射式气动雾化喷嘴开展了数值模拟,获得了气流流量、燃油流量和气液比对雾化性能的影响规律,喷嘴的雾化性能参数包括雾化粒径和雾化锥角。结果表明:气液比和气流流量对该型喷嘴的雾化性能有显著影响,燃油流量对雾化性能的影响较小;气液两相间相对速度是影响该型喷嘴雾化性能的决定因素,相对速度增大有利于减小雾化粒径,并增大雾化锥角;气流流量和气液比的增大均有利于雾化粒径的减小,燃油流量的增加将使雾化粒径增大;增大气流流量、气液比和减小燃油流量均可使雾化锥角增大;该型喷嘴的雾化锥角变化范围为30.12°~41.24°,雾化粒径变化范围为131.46~186.52μm。喷嘴可实现在较小的雾化锥角变化范围内获得较宽的雾化粒径变化,以此匹配燃气轮机燃烧室不同工作状态,具有较高的实用价值。

气液混合式人工造雪喷雾场的全貌及粒径分布研究

在北京冬奥会的推动下,国内冰雪产业迅速发展,特别是人造雪场的发展,给人工造雪的雪量和质量提出了更高的要求。目前的研究表明,人工造雪的质量与其喷雾场中液滴粒径分布息息相关,且液滴粒径分布不仅受到液滴碰撞、聚合、分离的影响,还受到人工造雪系统喷嘴间距分布的影响。因此,本文采用PIV系统和粒度仪测定了由气液混合式人工造雪系统经两个喷嘴雾化产生的喷雾场的整体形貌和液滴粒径分布,以此来研究人工造雪系统的气液质量混合比(g_(glr))和喷嘴间距对喷雾场中液滴粒径分布的影响。研究结果表明:随着g_(glr)的增大,喷雾场的整体形貌呈向内收缩的趋势,且在喷嘴正下方液滴平均粒径存在最小值,而当g_(glr)不变时,双喷嘴间的干涉现象随喷嘴间距的减小而增大,液滴的索特平均直径在随轴向距离增大而增大的同时,随径向距离的变化呈m型分布。

INSTABILITY OF GAS/LIQUID COAXIAL JET

In this article the emphasis was given to the discussion of the effects of diameter ratio and swirling on instability character for the gas/liquid coaxial jet used by Liao, et al.[1], The results indicate that the finite diameter ratio markedly increases the maximum growth rate, the most unstable wavenumber, as well as the cutoff wavenumber. It implies that the finite diameter ratio will lead to the liquid jet breakup length shorter and the liquid drop size smaller. The effect of the swirling jets is much more complex： for the axisymmetric perturbation mode, the swirling enhances the flow stability, for helical perturbation, the dominant instability mode occurs at n〈0. And it is found that in long wave region there exists a new kind of instability modes at n=l that was not mentioned in Liao et al.＇s article. For this new mode, there appears a dominated swirling ratio at which the flow has the maximum growth rate.

铝电解废旧阴极酸洗工艺对碳纯度的影响

为解决铝电解废旧阴极处理不当造成的环境污染和资源浪费问题,根据对酸洗工艺流程得分析完成了试验方案及设备的选型,在此基础上又重点完成了铝电解废旧阴极酸洗工艺反应温度、时间以及盐酸质量分数对碳纯度影响的试验,最终得到了最佳的酸洗工艺参数,为后续达到高效的铝电解废旧阴极处理效果奠定理论基础。

液相色谱/元素分析-同位素比值质谱联用法鉴定蜂蜜掺假

采用液相色谱/元素分析-同位素比值质谱联用法(LC/EA-IRMS)对国内蜂蜜掺假情况进行了研究。基于测定得到的38个纯正蜂蜜样品的碳同位素δ13C值数据,提出了纯正蜂蜜样品的δ13C值要求:蛋白质和蜂蜜的δ13C差值(Δδ13CP-H)≥-0.95‰,果糖和葡萄糖的δ13C差值(Δδ13CF-G)在-0.64‰至0.53‰范围内,各个组分间的δ13C最大差值(Δδ13Cmax)<2.09‰。对150个日常检测样品、蜂农和蜂蜜供应商的蜂蜜样品分别采用本文建立的LC/EA-IRMS和国家标准方法(EA-IRMS)进行鉴定,LC/EA-IRMS方法检出58个掺有C3或C4植物糖浆的阳性样品,而EA-IRMS方法仅检出7个掺有C4植物糖浆的阳性样品,可见新方法大大提高了对蜂蜜掺假的鉴别能力。