WorldWideScience

Sample records for chemical microreactors reversible

  1. Batch chemical microreactors: Reversible, in-situ UHV sealing of a microcavity

    DEFF Research Database (Denmark)

    Monkowski, Adam; Johansson, Martin; Nielsen, Jane Hvolbæk; Chorkendorff, Ib; Hansen, Ole

    We propose a new type of microreactor to study heterogeneous catalytic systems. The proposed device operates using a batch reactor scheme, in which catalyst and reactant are introduced in one step and analyzed in a subsequent step. This differs from a flow microreactor in which reaction and...... analysis take place continuously. A batch microreactor could evaluate the products from a very small amount of catalyst possibly...

  2. Chemical microreactor and method thereof

    Energy Technology Data Exchange (ETDEWEB)

    Morse, Jeffrey D. (Martinez, CA); Jankowski, Alan (Livermore, CA)

    2011-08-09

    A method for forming a chemical microreactor includes forming at least one capillary microchannel in a substrate having at least one inlet and at least one outlet, integrating at least one heater into the chemical microreactor, interfacing the capillary microchannel with a liquid chemical reservoir at the inlet of the capillary microchannel, and interfacing the capillary microchannel with a porous membrane near the outlet of the capillary microchannel, the porous membrane being positioned beyond the outlet of the capillary microchannel, wherein the porous membrane has at least one catalyst material imbedded therein.

  3. Microreactors

    OpenAIRE

    Zelić, B; Kurtanjek, Ž.; Tušek, A; Šalić, A.

    2010-01-01

    Nowadays, microreactors are finding increasing application in many fields, from the chemical industry and biotechnology to the pharmaceutical industry and medicine. They offer many fundamental and practical advantages over classical macroreactors (large surface to volume ratio, excellent mass and heat transfer, shorter retention time (Table 1), smaller amount of reagents, catalysts and waste products, laminar flow, effective mixing). Microreactors consist of a network of microsized channels e...

  4. Method for forming a chemical microreactor

    Science.gov (United States)

    Morse, Jeffrey D.; Jankowski, Alan

    2009-05-19

    Disclosed is a chemical microreactor that provides a means to generate hydrogen fuel from liquid sources such as ammonia, methanol, and butane through steam reforming processes when mixed with an appropriate amount of water. The microreactor contains capillary microchannels with integrated resistive heaters to facilitate the occurrence of catalytic steam reforming reactions. Two distinct embodiment styles are discussed. One embodiment style employs a packed catalyst capillary microchannel and at least one porous membrane. Another embodiment style employs a porous membrane with a large surface area or a porous membrane support structure containing a plurality of porous membranes having a large surface area in the aggregate, i.e., greater than about 1 m.sup.2/cm.sup.3. Various methods to form packed catalyst capillary microchannels, porous membranes and porous membrane support structures are also disclosed.

  5. Design of LTCC-based Ceramic Structure for Chemical Microreactor

    OpenAIRE

    D. Belavic; Hrovat, M.; G. Dolanc; Santo Zarnik, M.; Holc, J.; Makarovic, K.

    2012-01-01

    The design of ceramic chemical microreactor for the production of hydrogen needed in portable polymer-electrolyte membrane (PEM) fuel cells is presented. The microreactor was developed for the steam reforming of liquid fuels with water into hydrogen. The complex three-dimensional ceramic structure of the microreactor includes evaporator(s), mixer(s), reformer and combustor. Low-temperature co-fired ceramic (LTCC) technology was used to fabricate the ceramic structures with buried cavities and...

  6. Microreactor for fast chemical kinetics

    CERN Document Server

    Baroud, C N; Menetrier, L; Tabeling, P; Baroud, Charles N.; Okkels, Fridolin; Menetrier, Laure; Tabeling, Patrick

    2003-01-01

    The chemical reaction process in a T-shaped microchannel is studied experimentally through the reaction of Ca++ with a fluorescent tracer, Calcium-green. For thin channels (10 um), diffusion of species is found to behave in a way independent of the thickness direction. In such a situation, simulations of a two-dimensional reaction-diffusion model agree remarkably well with the experimental measurements. The comparison of experiments and simulations is used to measure the chemical kinetic constant, which we find to be k=3.2 x 10^5 dm^3/(mol s). Applications of the analysis to faster reactions and to micro-titration are also discussed.

  7. Microreactors

    Directory of Open Access Journals (Sweden)

    Zelić, B

    2010-05-01

    Full Text Available Nowadays, microreactors are finding increasing application in many fields, from the chemical industry and biotechnology to the pharmaceutical industry and medicine. They offer many fundamental and practical advantages over classical macroreactors (large surface to volume ratio, excellent mass and heat transfer, shorter retention time (Table 1, smaller amount of reagents, catalysts and waste products, laminar flow, effective mixing. Microreactors consist of a network of microsized channels etched into solid substrate (Fig. 1. Typical dimensions of microchannels are in the range from 10 µm to 500 µm. They are connected to a series of reservoirs for chemical reagents and products to form a complete device called “chip”. Microreactors can be produced from glass, silicon, quartz, metals and polymers. Optimal material depends on chemical compatibility with solvents and reagents, costs and detection methods used in process control. The most commonly used material is glass since it is chemically inert and transparent. One of the aims of today’s research in the field of microtechnolgy is developing of so-calledmicro-total-analysis-systems (µ-TAS; Fig. 3. Such a device would perform sampling, sample preparation, detection and data processing in integrated manner. The most µ-TAS research has been made in biomedical field (analysis of DNA and proteomics. Using microreactors, the complex process of scale up is replaced with numbering up (replication of microreactor units, eliminating time and costs necessary for transfer from laboratory to industrial production. Numbering up can be performed in two ways: external numbering up (connection of many devices in parallel and internal numbering up (parallel connection of functional elements, incomplete devices (Fig. 2. One of the biggest advantages of numbering up is that continuous operation is uninterrupted if one of the units fails, because it can be easily replaced with no effect on other parallel

  8. Integrated Microreactor for Chemical and Biochemical Applications

    Science.gov (United States)

    Schwesinger, N.; Dressler, L.; Frank, Th.; Wurmus, H.

    1995-01-01

    A completely integrated microreactor was developed that allows for the processing of very small amounts of chemical solutions. The entire system comprises several pumps and valves arranged in different branches as well as a mixing unit and a reaction chamber. The streaming path of each branch contains two valves and one pump each. The pumps are driven by piezoelectric elements mounted on thin glass membranes. Each pump is about 3.5 mm x 3.5 mm x 0.7 mm. A pumping rate up to 25 microliters per hour can be achieved. The operational voltage ranges between 40 and 200 V. A volume stroke up to 1.5 millimeter is achievable from the membrane structures. The valves are designed as passive valves. Sealing is by thin metal films. The dimension of a valve unit is 0.8 x 0.8. 07 mm. The ends of the separate streaming branches are arranged to meet in one point. This point acts as the beginning of a mixer unit which contains several fork-shaped channels. The arrangement of these channels allows for the division of the whole liquid stream into partial streams and their reuniting. A homogeneous mixing of solutions and/or gases can be observed after having passed about 10 of the fork elements. A reaction chamber is arranged behind the mixing unit to support the chemical reaction of special fluids. This unit contains heating elements placed outside of the chamber. The complete system is arranged in a modular structure and is built up of silicon. It comprises three silicon wafers bonded together by applying the silicon direct bonding technology. The silicon structures are made only by wet chemical etching processes. The fluid connections to the outside are realized using standard injection needles glued into v-shaped structures on the silicon wafers. It is possible to integrate other components, like sensors or electronic circuits using silicon as the basic material.

  9. Green and sustainable chemical synthesis using flow microreactors.

    Science.gov (United States)

    Yoshida, Jun-ichi; Kim, Heejin; Nagaki, Aiichiro

    2011-03-21

    Several features that allow flow microreactors contribute to green and sustainable chemical synthesis are presented: (1) For extremely fast reactions, kinetics often cannot be used because of the lack of homogeneity of the reaction environment when they are conducted in batch macroreactors. Better controllability, by virtue of fast mixing based on short diffusion paths in microreactors, however, leads to a higher selectivity of the products, based on kinetics considerations. Therefore, less waste is produced. (2) Reactions involving highly unstable intermediates usually require very low temperatures when they are conducted in macrobatch reactors. By virtue of short residence times, flow microreactors enable performing such reactions at ambient temperatures, avoiding cryogenic conditions and minimizing the energy required for cooling. (3) By virtue of the precise residence time control, flow microreactors allow to avoid the use of auxiliary substances such as protecting groups, enabling highly atom- and step-economical straightforward syntheses. The development of several test plants based on microreaction technology has proved that flow microreactor synthesis can be applied to the green and sustainable production of chemical substances on industrial scales. (4) Microreactor technology enables on-demand and on-site synthesis, which leads to less energy for transportation and easy recycling of substances. PMID:21394921

  10. Design of LTCC-based Ceramic Structure for Chemical Microreactor

    Directory of Open Access Journals (Sweden)

    D. Belavic

    2012-04-01

    Full Text Available The design of ceramic chemical microreactor for the production of hydrogen needed in portable polymer-electrolyte membrane (PEM fuel cells is presented. The microreactor was developed for the steam reforming of liquid fuels with water into hydrogen. The complex three-dimensional ceramic structure of the microreactor includes evaporator(s, mixer(s, reformer and combustor. Low-temperature co-fired ceramic (LTCC technology was used to fabricate the ceramic structures with buried cavities and channels, and thick-film technology was used to make electrical heaters, temperature sensors and pressure sensors. The final 3D ceramic structure consists of 45 LTCC tapes. The dimensions of the structure are 75 × 41 × 9 mm3 and the weight is about 73 g.

  11. Molecular imprinting in hydrogels using reversible addition-fragmentation chain transfer polymerization and continuous flow micro-reactor

    OpenAIRE

    Kadhirvel, Porkodi; Machado, Carla; Freitas, Ana; Oliveira, Tânia; Dias, Rolando; Costa, Mário

    2015-01-01

    Abstract BACKGROUND Stimuli responsive imprinted hydrogel micro-particles were prepared using reversible addition-fragmentation chain transfer polymerization for targeting genotoxic impurity aminopyridine in aqueous environment using a continuous flow micro-reactor. RESULTS The feasibility of operation with a continuous flow micro-reactor for particles production was demonstrated. A comparative evaluation was carried out between batch and micro-reactor produced imprinted and non...

  12. Modeling chemical vapor deposition of silicon dioxide in microreactors at atmospheric pressure

    International Nuclear Information System (INIS)

    We developed a multiphysics mathematical model for simulation of silicon dioxide Chemical Vapor Deposition (CVD) from tetraethyl orthosilicate (TEOS) and oxygen mixture in a microreactor at atmospheric pressure. Microfluidics is a promising technology with numerous applications in chemical synthesis due to its high heat and mass transfer efficiency and well-controlled flow parameters. Experimental studies of CVD microreactor technology are slow and expensive. Analytical solution of the governing equations is impossible due to the complexity of intertwined non-linear physical and chemical processes. Computer simulation is the most effective tool for design and optimization of microreactors. Our computational fluid dynamics model employs mass, momentum and energy balance equations for a laminar transient flow of a chemically reacting gas mixture at low Reynolds number. Simulation results show the influence of microreactor configuration and process parameters on SiO2 deposition rate and uniformity. We simulated three microreactors with the central channel diameter of 5, 10, 20 micrometers, varying gas flow rate in the range of 5-100 microliters per hour and temperature in the range of 300-800 °C. For each microchannel diameter we found an optimal set of process parameters providing the best quality of deposited material. The model will be used for optimization of the microreactor configuration and technological parameters to facilitate the experimental stage of this research

  13. Controlling hazardous chemicals in microreactors: Synthesis with iodine azide

    Directory of Open Access Journals (Sweden)

    Johan C. Brandt

    2009-06-01

    Full Text Available Aromatic aldehydes have been converted into the corresponding carbamoyl azides using iodine azide. These reactions have been performed safely under continuous flow reaction conditions in microreactors.

  14. REVERSE MICROEMULSION OF IGEPAL Co-720 SYSTEM AS MICROREACTOR FOR CdS SYNTHESIS

    Directory of Open Access Journals (Sweden)

    Fitria Rahmawati

    2016-08-01

    Full Text Available A Research on CdS synthesis in reverse microemulsion of Igepal CO-720 system has been conducted at various weight ratio of water to surfactant. Igepal CO-720 naturally forms oil in water (o/w emulsion type due to its high HLB (Hydrophilic -Lipophilic Balance value. Therefore, in this research the Igepal CO-720 system was inversed into water in oil (w/o system before it was used as microreactor for CdS synthesis. As comparison, a system of AOT (Aerosol OT; sodium bis (2-ethylhexyl sulfosuccinate which is naturally w/o system was also used as microreactor for CdS synthesis. The prepared CdS was analyzed by X-ray diffraction for crystal identification, scanning electron microscope for morphological analysis, UV-Vis for absorption edge determination and photoelectrochemical testing for photoactivity. The results show that the Igepal CO -720 system can be inverted into w/o system and can be used as microreactor for CdS synthesis. The prepared CdS is in nanosize with the average diameter of 2.517 ± 0.014 nm and the average gap energy of 3.805 ± 0.178 eV. The prepared CdS in Igepal CO-720 system has less regular form in comparison with morphology of the prepared CdS in AOT system. As the ω values decreases the particle diameter decreases, the gap energy increases and the % IPCE increases. It indicates that high surfactant concentration allows small size micelles formation and produced smaller CdS particle that has high surface area and therefore provide higher photocatalytic activity which was indicated by high value of its % IPCE.

  15. RADICAL QUENCHING OF METHANE-AIR PREMIXED FLAME IN MICROREACTORS USING DETAILED CHEMICAL KINETICS

    Directory of Open Access Journals (Sweden)

    JUNJIE CHEN

    2015-10-01

    Full Text Available The steady hetero-/homogeneous combustion of lean methane-air mixtures in plane channel-flow microreactors was investigated numerically to elucidate the effects of wall material and initial sticking coefficient on radical quenching. Simulations were performed with a two-dimensional numerical model employing detailed reaction mechanisms to examine the interaction between heterogeneous and homogeneous reactions on platinum, alumina, quartz and copper. Comparisons among wall materials revealed that the wall chemical effect plays a vital role in the distribution of OH* radical. Homogeneous reaction of methane over platinum is significantly inhibited due to the rapid depletion of reactants on catalytic surfaces, rather than the radical adsorption. The inhibition of radical quenching on the surface of alumina is most pronounced. As the microreactor is smaller than the critical dimension of 0.7 mm, the wall chemical effect on flame characteristics becomes of great importance.

  16. Whole ceramic-like microreactors from inorganic polymers for high temperature or/and high pressure chemical syntheses.

    Science.gov (United States)

    Ren, Wurong; Perumal, Jayakumar; Wang, Jun; Wang, Hao; Sharma, Siddharth; Kim, Dong-Pyo

    2014-02-21

    Two types of whole ceramic-like microreactors were fabricated from inorganic polymers, polysilsesquioxane (POSS) and polyvinylsilazane (PVSZ), that were embedded with either perfluoroalkoxy (PFA) tube or polystyrene (PS) film templates, and subsequently the templates were removed by physical removal (PFA tube) or thermal decomposition (PS). A POSS derived ceramic-like microreactor with a 10 cm long serpentine channel was obtained by an additional "selective blocking of microchannel" step and subsequent annealing at 300 °C for 1 h, while a PVSZ derived ceramic-like microreactor with a 14 cm long channel was yielded by a co-firing process of the PVSZ-PS composite at 500 °C for 2 h that led to complete decomposition of the film template leaving a microchannel behind. The obtained whole ceramic-like microfluidic devices revealed excellent chemical and thermal stabilities in various solvents, and they were able to demonstrate unique chemical performance at high temperature or/and high pressure conditions such as Michaelis-Arbuzov rearrangement at 150-170 °C, Wolff-Kishner reduction at 200 °C, synthesis of super-paramagnetic Fe3O4 nanoparticles at 320 °C and isomerisation of allyloxybenzene to 2-allylphenol (250 °C and 400 psi). These economic ceramic-like microreactors fabricated by a facile non-lithographic method displayed excellent utility under challenging conditions that is superior to any plastic microreactors and comparable to glass and metal microreactors with high cost. PMID:24356091

  17. Chemical bath deposition of semiconductor thin films & nanostructures in novel microreactors

    Science.gov (United States)

    McPeak, Kevin M.

    Chemical bath deposition (CBD) offers a simple and inexpensive route to deposit semiconductor nanostructures and thin films, but lack of fundamental understanding and control of the underlying chemistry has limited its versatility. CBD is traditionally performed in a batch reactor, requiring only a substrate to be immersed in a supersaturated solution of aqueous precursors such as metal salts, complexing agents, and pH buffers. Highlights of CBD include low cost, operation at low temperature and atmospheric pressure, and scalability to large area substrates. In this dissertation, I explore CBD of semiconductor thin films and nanowire arrays in batch and continuous flow microreactors. Microreactors offer many advantages over traditional reactor designs including a reduction in mass transport limitations, precise temperature control and ease of production scale-up by "numbering up". Continuous flow micoreactors offer the unique advantage of providing reaction conditions that are time-invariant but change smoothly as a function of distance down the reaction channel. Growth from a bath whose composition changes along the reactor length results in deposited materials whose properties vary as a function of position on the substrate, essentially creating a combinatorial library. These substrates can be rapidly characterized to identify relationships between growth conditions and material properties or growth mechanisms. I have used CBD in a continuous flow microreactor to deposit ZnO nanowire arrays and CdZnS films whose optoelectronic properties vary as a function of position. The spatially-dependent optoelectronic properties of these materials have been correlated to changes in the composition, structure or growth mechanisms of the materials and ultimately their growth conditions by rigorous spatial characterization. CBD in a continuous flow microreactor, coupled with spatial characterization, provides a new route to understanding the connection between CBD growth

  18. Design of microreactor by integration of reverse engineering and direct metal laser sintering process

    Energy Technology Data Exchange (ETDEWEB)

    Bineli, Aulus Roberto Romao; Gimenez Perez, Ana Paula; Bernardes, Luiz Fernando; Munhoz, Andre Luiz Jardini; Maciel Filho, Rubens [Universidade de Campinas (LOPCA/UNICAMP), SP (Brazil). School of Chemical Engineering. Laboratory of Optimization, Design and Advanced Process Control], Email: aulus@feq.unicamp.br

    2010-07-01

    The propose of this work is to present high precision microfabrication facilities using computer aided technologies as Reverse Engineering (RE) and Rapid Manufacturing (RM) to analyze, design and construct micro reactors to produce high content hydrogen gas. Micro reactors are very compact, have a high surface to volume ratio, exhibit enhanced heat and mass transfer rates, denotes extremely low pressure drop and allow improved thermal integration in the processes involved. The main goals of micro reactors are the optimization of conventional chemical plants and low footprint, opening different ways to research new process technologies and synthesis of new products. In this work, a microchannels plate and housing structure of these plates were fabricated using DMLS method (Direct Metal Laser Sintering). The plates were analyzed to verify the minimum thickness wall that machine can produce, and the housing structure were digitalized, using a 3D scanning, to perform a 3D inspection and to verify the deflection of the constructed part in comparison with original CAD design models. It was observed that DMLS systems are able to produce micro reactors and microchannels plates with high precision at different metallic materials. However, it is important to choose appropriate conditions to avoid residual stresses and consequently warping parts. (author)

  19. Microreactors for Studying Enantioselective Reactions

    Czech Academy of Sciences Publication Activity Database

    Pavlorková, Jana

    Prague: Faculty of Chemical Technology, ICT, 2014. [Conference of Post-graduate Students. Prague (CZ), 26.06.2014] Institutional support: RVO:67985858 Keywords : enantioselective reactions * microreactors * molecular chirality Subject RIV: CI - Industrial Chemistry, Chemical Engineering

  20. Microreactor Array Device

    Science.gov (United States)

    Wiktor, Peter; Brunner, Al; Kahn, Peter; Qiu, Ji; Magee, Mitch; Bian, Xiaofang; Karthikeyan, Kailash; Labaer, Joshua

    2015-03-01

    We report a device to fill an array of small chemical reaction chambers (microreactors) with reagent and then seal them using pressurized viscous liquid acting through a flexible membrane. The device enables multiple, independent chemical reactions involving free floating intermediate molecules without interference from neighboring reactions or external environments. The device is validated by protein expressed in situ directly from DNA in a microarray of ~10,000 spots with no diffusion during three hours incubation. Using the device to probe for an autoantibody cancer biomarker in blood serum sample gave five times higher signal to background ratio compared to standard protein microarray expressed on a flat microscope slide. Physical design principles to effectively fill the array of microreactors with reagent and experimental results of alternate methods for sealing the microreactors are presented.

  1. Applications of microreactor in chemistry and chemical engineering%微反应器在化学化工领域中的应用

    Institute of Scientific and Technical Information of China (English)

    刘兆利; 张鹏飞

    2016-01-01

    微反应器是微型化学反应系统,具有换热和传质效率高、严格控制反应时间、易于放大、安全性能好等特点。和传统搅拌反应器相比,这些特点使得微反应器在缩短反应时间、大幅度提高化学反应的转化率和产品收率等方面展现出一定的优势。但微反应器也存在易堵塞,催化剂负载、微通道的设计与制造难度大等问题。本文介绍了近年来快速发展的微反应器技术,回顾了微反应器的特点,重点探讨微反应器在化学化工领域的应用以及微反应器在精细化工和制药工业、生物化工领域的应用实例,讨论了微反应器目前存在的诸多挑战。微反应器目前是化学和化工学科的前沿和热点方向,分析表明微反应器仍然有很大的发展空间,有潜力改变化学化工前景。提出应进一步深入系统地认识微反应器内化学反应以及微通道设计的基本规律和机理,将微反应器技术引入更广泛的反应体系中,加强微反应器的集成化水平。%Microreactor belongs to the miniature chemical reaction system,which has some characteristics of high heat- and mass- transfer rates,strictly-controlled reaction time,easy scale-up, excellent safety performance,and so on. Comparing with the common batch reactors,advantages of microreactors are reducing reaction time,greatly promoting conversion and yields. On the other hand, there are some existing challenges,such as the clogging problem,catalyst loading,design and fabrication of microchannels,and so on. This paper aims to introduce the microreactor technology, which has been growing rapidly in recent years. Some of the basic characteristics of microreactor are summarized focusing on applications of microreactor in chemistry and chemical engineering as well as some of typical examples of existing in fine chemical and pharmaceutical industry. A variety of challenges are also discussed. Microreactor is a

  2. Scalable microreactors and methods for using same

    Science.gov (United States)

    Lawal, Adeniyi; Qian, Dongying

    2010-03-02

    The present invention provides a scalable microreactor comprising a multilayered reaction block having alternating reaction plates and heat exchanger plates that have a plurality of microchannels; a multilaminated reactor input manifold, a collecting reactor output manifold, a heat exchange input manifold and a heat exchange output manifold. The present invention also provides methods of using the microreactor for multiphase chemical reactions.

  3. Sample Handling and Chemical Kinetics in an Acoustically Levitated Drop Microreactor

    Science.gov (United States)

    2009-01-01

    Accurate measurement of enzyme kinetics is an essential part of understanding the mechanisms of biochemical reactions. The typical means of studying such systems use stirred cuvettes, stopped-flow apparatus, microfluidic systems, or other small sample containers. These methods may prove to be problematic if reactants or products adsorb to or react with the container’s surface. As an alternative approach, we have developed an acoustically-levitated drop reactor eventually intended to study enzyme-catalyzed reaction kinetics related to free radical and oxidative stress chemistry. Microliter-scale droplet generation, reactant introduction, maintenance, and fluid removal are all important aspects in conducting reactions in a levitated drop. A three capillary bundle system has been developed to address these needs. We report kinetic measurements for both luminol chemiluminescence and the reaction of pyruvate with nicotinamide adenine dinucleotide, catalyzed by lactate dehydrogenase, to demonstrate the feasibility of using a levitated drop in conjunction with the developed capillary sample handling system as a microreactor. PMID:19769373

  4. Chemical reactions in reverse micelle systems

    Science.gov (United States)

    Matson, Dean W.; Fulton, John L.; Smith, Richard D.; Consani, Keith A.

    1993-08-24

    This invention is directed to conducting chemical reactions in reverse micelle or microemulsion systems comprising a substantially discontinuous phase including a polar fluid, typically an aqueous fluid, and a microemulsion promoter, typically a surfactant, for facilitating the formation of reverse micelles in the system. The system further includes a substantially continuous phase including a non-polar or low-polarity fluid material which is a gas under standard temperature and pressure and has a critical density, and which is generally a water-insoluble fluid in a near critical or supercritical state. Thus, the microemulsion system is maintained at a pressure and temperature such that the density of the non-polar or low-polarity fluid exceeds the critical density thereof. The method of carrying out chemical reactions generally comprises forming a first reverse micelle system including an aqueous fluid including reverse micelles in a water-insoluble fluid in the supercritical state. Then, a first reactant is introduced into the first reverse micelle system, and a chemical reaction is carried out with the first reactant to form a reaction product. In general, the first reactant can be incorporated into, and the product formed in, the reverse micelles. A second reactant can also be incorporated in the first reverse micelle system which is capable of reacting with the first reactant to form a product.

  5. Surface Modification for Microreactor Fabrication

    Directory of Open Access Journals (Sweden)

    Wladyslaw Torbicz

    2006-04-01

    Full Text Available In this paper, methods of surface modification of different supports, i.e. glass andpolymeric beads for enzyme immobilisation are described. The developed method ofenzyme immobilisation is based on Schiff’s base formation between the amino groups onthe enzyme surface and the aldehyde groups on the chemically modified surface of thesupports. The surface of silicon modified by APTS and GOPS with immobilised enzymewas characterised by atomic force microscopy (AFM, time-of-flight secondary ion massspectroscopy (ToF-SIMS and infrared spectroscopy (FTIR. The supports withimmobilised enzyme (urease were also tested in combination with microreactors fabricatedin silicon and Perspex, operating in a flow-through system. For microreactors filled withurease immobilised on glass beads (Sigma and on polymeric beads (PAN, a very high andstable signal (pH change was obtained. The developed method of urease immobilisationcan be stated to be very effective.

  6. Catalytic microreactors for portable power generation

    Energy Technology Data Exchange (ETDEWEB)

    Karagiannidis, Symeon [Paul Scherer Institute, Villigen (Switzerland)

    2011-07-01

    ''Catalytic Microreactors for Portable Power Generation'' addresses a problem of high relevance and increased complexity in energy technology. This thesis outlines an investigation into catalytic and gas-phase combustion characteristics in channel-flow, platinum-coated microreactors. The emphasis of the study is on microreactor/microturbine concepts for portable power generation and the fuels of interest are methane and propane. The author carefully describes numerical and experimental techniques, providing a new insight into the complex interactions between chemical kinetics and molecular transport processes, as well as giving the first detailed report of hetero-/homogeneous chemical reaction mechanisms for catalytic propane combustion. The outcome of this work will be widely applied to the industrial design of micro- and mesoscale combustors. (orig.)

  7. Mass transfer with complex reversible chemical reactions—II. parallel reversible chemical reactions

    NARCIS (Netherlands)

    Versteeg, G.F.; Kuipers, J.A.M.; Beckum, F.P.H. van; Swaaij, W.P.M. van

    1990-01-01

    An absorption model has been developed which can be used to calculate rapidly absorption rates for the phenomenon mass transfer accompanied by multiple complex parallel reversible chemical reactions. This model can be applied for the calculation of the mass transfer rates, enhancement factors and co

  8. Mass transfer with complex reversible chemical reactions. II: Parallel reversible chemical reactions

    NARCIS (Netherlands)

    Versteeg, G.F.; Kuipers, J.A.M.; Beckum, van F.P.H.; Swaaij, van W.P.M.

    1990-01-01

    An absorption model has been developed which can be used to calculate rapidly absorption rates for the phenomenon mass transfer accompanied by multiple complex parallel reversible chemical reactions. This model can be applied for the calculation of the mass transfer rates, enhancement factors and co

  9. Microreactor Technology for On-Site Production of Methyl Chloride

    Czech Academy of Sciences Publication Activity Database

    Schmidt, S.A.; Vajglová, Zuzana; Eränen, K.; Murzin, D.Y.; Salmi, T.

    2014-01-01

    Roč. 3, č. 5 (2014), s. 345-352. ISSN 2191-9542 Institutional support: RVO:67985858 Keywords : chloromethane * intensification * microreactor * product separation Subject RIV: CI - Industrial Chemistry, Chemical Engineering Impact factor: 1.125, year: 2014

  10. Testing of the Micro-Reactor System

    Czech Academy of Sciences Publication Activity Database

    Beneš, Ondřej; Hanková, Libuše; Klusoň, Petr; Šolcová, Olga

    Bratislava: Slovak Society of Chemical Engineering, 2015 - (Markoš, J.), s. 40 ISBN 978-80-89475-14-8. [International Conference of Slovak Society of Chemical Engineering /42./. Tatranské Matliare (SK), 25.05.2015-29.05.2015] R&D Projects: GA ČR GA15-14228S Institutional support: RVO:67985858 Keywords : micro-reactor technology * testing * partial oxidation Subject RIV: CI - Industrial Chemistry, Chemical Engineering

  11. Integrated Microreactors for Reaction Automation: New Approaches to Reaction Development

    Science.gov (United States)

    McMullen, Jonathan P.; Jensen, Klavs F.

    2010-07-01

    Applications of microsystems (microreactors) in continuous-flow chemistry have expanded rapidly over the past two decades, with numerous reports of higher conversions and yields compared to conventional batch benchtop equipment. Synthesis applications are enhanced by chemical information gained from integrating microreactor components with sensors, actuators, and automated fluid handling. Moreover, miniaturized systems allow experiments on well-defined samples at conditions not easily accessed by conventional means, such as reactions at high pressure and temperatures. The wealth of synthesis information that could potentially be acquired through use of microreactors integrated with physical sensors and analytical chemistry techniques for online reaction monitoring has not yet been well explored. The increased efficiency resulting from use of continuous-flow microreactor platforms to automate reaction screening and optimization encourages a shift from current batchwise chemical reaction development to this new approach. We review advances in this new area and provide application examples of online monitoring and automation.

  12. Fabrication of SU-8 microreactors for radiopharmaceutical production

    OpenAIRE

    Zizzari, A; Arima, Valentina; Zacheo, A.; Pascali, Giancarlo; Salvadori, Piero; Perrone, E; Mangiullo, D; Rinaldi, Ross

    2011-01-01

    SU-8 is a very interesting material for the fabrication of lab-on-chip devices applied to organic synthesis because of its resistance to chemicals and solvents. Among the possible application fields of microreactor technology, radiochemistry is emerging because microfluidic apparatuses allow to perform radiosynthesis in a quicker, safer and more reliable way compared to traditional vessel-based approaches. Microreactors for synthesizing [18F]-labelled radiopharmaceuticals require the employme...

  13. Parametric study of hydrogen production from ethanol steam reforming in a membrane microreactor

    OpenAIRE

    M. de-Souza; G. M. Zanin; F. F. Moraes

    2013-01-01

    Microreactors are miniaturized chemical reaction systems, which contain reaction channels with characteristic dimensions in the range of 10-500 µm. One possible application for microreactors is the conversion of ethanol to hydrogen used in fuel cells to generate electricity. In this paper a rigorous isothermal, steady-state two-dimensional model was developed to simulate the behavior of a membrane microreactor based on the hydrogen yield from ethanol steam reforming. Furthermore, this membran...

  14. DNA computing in microreactors

    Science.gov (United States)

    Wagler, Patrick; van Noort, Danny; McCaskill, John S.

    2001-11-01

    The goal of this research is to improve the modular stability and programmability of DNA-based computers and in a second step towards optical programmable DNA computing. The main focus here is on hydrodynamic stability. Clockable microreactors can be connected in various ways to solve combinatorial optimisation problems, such as Maximum Clique or 3-SAT. This work demonstrates by construction how one micro-reactor design can be programmed to solve any instance of Maximum Clique up to its given maximum size (N). It reports on an implementation of the architecture proposed previously. This contrasts with conventional DNA computing where the individual sequence of biochemical operations depends on the specific problem. In this pilot study we are tackling a graph for the Maximum Clique problem with N

  15. Testing of the Micro-Reactor System

    Czech Academy of Sciences Publication Activity Database

    Krystyník, Pavel; Beneš, Ondřej; Klusoň, Petr; Šolcová, Olga

    Praha: Česká společnost průmyslové chemie, 2015, s. 30 /p104./. ISBN 978-80-86238-73-9. [mezinárodní chemicko-technologická konference (ICCT 2015) /3./. Mikulov (CZ), 13.04.2015-15.04.2015] R&D Projects: GA ČR GA15-14228S Institutional support: RVO:67985858 Keywords : micro-reactor technology * heat transfer * testing Subject RIV: CI - Industrial Chemistry, Chemical Engineering

  16. Assessment of the Kinetic Regime for 2-Methylpropene Hydrogenation in a Packed-Bed Microreactor

    Czech Academy of Sciences Publication Activity Database

    Vajglová, Zuzana; Stavárek, Petr; Křišťál, Jiří; Kolena, J.; Jiřičný, Vladimír

    Budapest: Budapest University of Technology and Economics, 2014, s. 189-190. ISBN 978-963-05-9518-6. [International Conference on Microreactor Technology IMRET /13./. Budapest (HU), 23.06.2014-25.06.2014] Institutional support: RVO:67985858 Keywords : hydrogenation of 2-methylpropene * packed-bed microreactor * kinetic regime Subject RIV: CI - Industrial Chemistry, Chemical Engineering

  17. Flow microreactor synthesis in organo-fluorine chemistry

    Directory of Open Access Journals (Sweden)

    Hideki Amii

    2013-12-01

    Full Text Available Organo-fluorine compounds are the substances of considerable interest in various industrial fields due to their unique physical and chemical properties. Despite increased demand in wide fields of science, synthesis of fluoro-organic compounds is still often faced with problems such as the difficulties in handling of fluorinating reagents and in controlling of chemical reactions. Recently, flow microreactor synthesis has emerged as a new methodology for producing chemical substances with high efficiency. This review outlines the successful examples of synthesis and reactions of fluorine-containing molecules by the use of flow microreactor systems to overcome long-standing problems in fluorine chemistry.

  18. An optically accessible pyrolysis microreactor

    Energy Technology Data Exchange (ETDEWEB)

    Baraban, J. H.; Ellison, G. Barney [Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309 (United States); David, D. E. [Integrated Instrument Development Facility, CIRES, University of Colorado, Boulder, Colorado 80309-0216 (United States); Daily, J. W. [Department of Mechanical Engineering, University of Colorado at Boulder, Boulder, Colorado 80309 (United States)

    2016-01-15

    We report an optically accessible pyrolysis micro-reactor suitable for in situ laser spectroscopic measurements. A radiative heating design allows for completely unobstructed views of the micro-reactor along two axes. The maximum temperature demonstrated here is only 1300 K (as opposed to 1700 K for the usual SiC micro-reactor) because of the melting point of fused silica, but alternative transparent materials will allow for higher temperatures. Laser induced fluorescence measurements on nitric oxide are presented as a proof of principle for spectroscopic characterization of pyrolysis conditions.

  19. An optically accessible pyrolysis microreactor

    Science.gov (United States)

    Baraban, J. H.; David, D. E.; Ellison, G. Barney; Daily, J. W.

    2016-01-01

    We report an optically accessible pyrolysis micro-reactor suitable for in situ laser spectroscopic measurements. A radiative heating design allows for completely unobstructed views of the micro-reactor along two axes. The maximum temperature demonstrated here is only 1300 K (as opposed to 1700 K for the usual SiC micro-reactor) because of the melting point of fused silica, but alternative transparent materials will allow for higher temperatures. Laser induced fluorescence measurements on nitric oxide are presented as a proof of principle for spectroscopic characterization of pyrolysis conditions.

  20. An optically accessible pyrolysis microreactor

    International Nuclear Information System (INIS)

    We report an optically accessible pyrolysis micro-reactor suitable for in situ laser spectroscopic measurements. A radiative heating design allows for completely unobstructed views of the micro-reactor along two axes. The maximum temperature demonstrated here is only 1300 K (as opposed to 1700 K for the usual SiC micro-reactor) because of the melting point of fused silica, but alternative transparent materials will allow for higher temperatures. Laser induced fluorescence measurements on nitric oxide are presented as a proof of principle for spectroscopic characterization of pyrolysis conditions

  1. An RF-powered micro-reactor for the detection of astrobiological target molecules on planetary bodies

    OpenAIRE

    Scott, Valerie J.; Tse, Margaret; Shearn, Michael J.; Siegel, Peter H.; Amashukeli, Xenia

    2012-01-01

    We describe a sample-processing micro-reactor that utilizes 60 GHz RF radiation with approximately 730 mW of output power. The instrument design and performance characterization are described and then illustrated with modeling and experimental studies. The micro-reactor's efficiency on affecting hydrolysis of chemical bonds similar to those within large complex molecules was demonstrated: a disaccharide—sucrose—was hydrolyzed completely under micro-reactor conditions. The products of the micr...

  2. On the steady states of weakly reversible chemical reaction networks

    OpenAIRE

    Deng, Jian; Jones, Christopher; Feinberg, Martin; Nachman, Adrian

    2011-01-01

    A natural condition on the structure of the underlying chemical reaction network, namely weak reversibility, is shown to guarantee the existence of an equilibrium (steady state) in each positive stoichiometric compatibility class for the associated mass-action system. Furthermore, an index formula is given for the set of equilibria in a given stoichiometric compatibility class.

  3. Imaging of oxygen in microreactors and microfluidic systems

    Science.gov (United States)

    Sun, Shiwen; Ungerböck, Birgit; Mayr, Torsten

    2015-09-01

    This review gives an overview on the state-of-the-art of oxygen imaging in microfluidics. Oxygen imaging using optical oxygen sensors based on luminescence is a versatile and powerful tool for obtaining profoundly space-resolved information of oxygen in microreactors and microfluidic systems. We briefly introduce the principle of oxygen imaging and present techniques of oxygen imaging applied in microreactors and microfluidic devices, including selection criteria and demands of sensing material and basic set-up for a 2D oxygen sensing system. A detailed review of oxygen imaging in microreactors and microfluidic systems is given on different applications in oxygen gradient monitoring, cell culturing, single-cell analysis and chemical reactions. Finally, we discuss challenges and trends of oxygen imaging in microfluidic systems.

  4. Microreactor Platforms for HomogeneousHydrogenations and Photocatalytic Reactions

    Czech Academy of Sciences Publication Activity Database

    Pavlorková, Jana; Křišťál, Jiří; Drhová, Magdalena; Hejda, S.; Klusoň, Petr

    Prague: KANAG -TISK, 2014 - (Krýsa, J.; Klusoň, P.), s. 43-45 ISBN 978-80-7080-886-3. [Czech-Austrian Workshop: New Trends in Photo and Electro Catalysis /6./. Hnanice (CZ), 02.12.2013-04.12.2013] Institutional support: RVO:67985858 Keywords : microreactors * homogeneous catalysis * photocatalysis Subject RIV: CI - Industrial Chemistry, Chemical Engineering

  5. Microreactor as Efficient Tool for Light Induced Oxidation Reactions

    Czech Academy of Sciences Publication Activity Database

    Hejda, S.; Drhová, Magdalena; Křišťál, Jiří; Buzek, D.; Krystyník, Pavel; Klusoň, Petr

    2014-01-01

    Roč. 255, NOV 1 (2014), s. 178-184. ISSN 1385-8947 Grant ostatní: GA MŠMT(CZ) MŠk:CZ.1.07/2.2.00/28.0205 Institutional support: RVO:67985858 Keywords : photo microreactor * phthalocyanine * chlorophenol oxidation Subject RIV: CI - Industrial Chemistry, Chemical Engineering Impact factor: 4.321, year: 2014

  6. Effective use of enzyme microreactors : thermal, kinetic and ethical guidelines

    NARCIS (Netherlands)

    Swarts, J.W.

    2009-01-01

    Microreactor technology is reported to have many benefits over regular chemical methods. Due to the small dimensions over which temperature and concentration gradients can exist, mass and heat transfer can be very quick. This could minimize the time needed for heating and mixing, due to a reduction

  7. Optimal design of multi-channel microreactor for uniform residence time distribution

    OpenAIRE

    Renault, Cyril; Colin, Stéphane; Orieux, Stéphane; Cognet, Patrick; Tzedakis, Théodore

    2012-01-01

    Multi-channel microreactors can be used for various applications that require chemical or electrochemical reactions in either liquid, gaseous or multi phase. For an optimal control of the chemical reactions, one key parameter for the design of such microreactors is the residence time distribution of the fluid, which should be as uniform as possible in the series of microchannels that make up the core of the reactor. Based on simplifying assumptions, an analytical model is proposed for optimiz...

  8. Flow microreactor synthesis in organo-fluorine chemistry

    OpenAIRE

    Hideki Amii; Aiichiro Nagaki; Jun-ichi Yoshida

    2013-01-01

    Organo-fluorine compounds are the substances of considerable interest in various industrial fields due to their unique physical and chemical properties. Despite increased demand in wide fields of science, synthesis of fluoro-organic compounds is still often faced with problems such as the difficulties in handling of fluorinating reagents and in controlling of chemical reactions. Recently, flow microreactor synthesis has emerged as a new methodology for producing chemical substances with high ...

  9. Coaxial microreactor for particle synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Bartsch, Michael; Kanouff, Michael P; Ferko, Scott M; Crocker, Robert W; Wally, Karl

    2013-10-22

    A coaxial fluid flow microreactor system disposed on a microfluidic chip utilizing laminar flow for synthesizing particles from solution. Flow geometries produced by the mixing system make use of hydrodynamic focusing to confine a core flow to a small axially-symmetric, centrally positioned and spatially well-defined portion of a flow channel cross-section to provide highly uniform diffusional mixing between a reactant core and sheath flow streams. The microreactor is fabricated in such a way that a substantially planar two-dimensional arrangement of microfluidic channels will produce a three-dimensional core/sheath flow geometry. The microreactor system can comprise one or more coaxial mixing stages that can be arranged singly, in series, in parallel or nested concentrically in parallel.

  10. Parametric study of hydrogen production from ethanol steam reforming in a membrane microreactor

    Directory of Open Access Journals (Sweden)

    M. de-Souza

    2013-06-01

    Full Text Available Microreactors are miniaturized chemical reaction systems, which contain reaction channels with characteristic dimensions in the range of 10-500 µm. One possible application for microreactors is the conversion of ethanol to hydrogen used in fuel cells to generate electricity. In this paper a rigorous isothermal, steady-state two-dimensional model was developed to simulate the behavior of a membrane microreactor based on the hydrogen yield from ethanol steam reforming. Furthermore, this membrane microreactor is compared to a membraneless microreactor. A potential advantage of the membrane microreactor is the fact that both ethanol steam reforming and the separation of hydrogen by a permselective membrane occur in one single microdevice. The simulation results for steam reforming yields are in agreement with experimental data found in the literature. The results show that the membrane microreactorpermits a hydrogen yield of up to 0.833 which is more than twice that generated by the membraneless reactor. More than 80% of the generated hydrogen permeates through the membrane and, due to its high selectivity, the membrane microreactor delivers high-purity hydrogen to the fuel cell.

  11. The Partial Oxidation in Micro-Reactor System

    Czech Academy of Sciences Publication Activity Database

    Beneš, Ondřej; Pavlorková, Jana; Klusoň, Petr; Šolcová, Olga

    Bratislava: AXIMA Graphics Design & Printing Services, 2014, s. 34 ISBN 978-80-89475-13-1. [International Conference of Slovak Society of Chemical Engineering /41./. Tatranské Matliare (SK), 26.05.2014-30.05.2014] Grant ostatní: RFCS(XE) RFCR-CT-2011-00002 Institutional support: RVO:67985858 Keywords : micro-reactor * micro-photo-reactor * partial oxidation Subject RIV: CI - Industrial Chemistry, Chemical Engineering

  12. Experimental and modelling studies on liquid-liquid slug flow capillary microreactors

    OpenAIRE

    Kashid, Madhvanand N.

    2008-01-01

    Microreactor technology, an important method of process intensification, offers potential benefits to the chemical process industries due to the well-defined high specific interfacial area available for heat and mass transfer, which increases transfer rates, and enhances safety resulting from low hold-ups. The liquid-liquid slug flow capillary microreactor intensifies the mass transfer in biphasic systems through internal circulation caused by the shear between continuous phase/wall surface a...

  13. Chemical respiratory allergy: Reverse engineering an adverse outcome pathway

    International Nuclear Information System (INIS)

    Allergic sensitisation of the respiratory tract by chemicals is associated with rhinitis and asthma and remains an important occupational health issue. Although less than 80 chemicals have been confirmed as respiratory allergens the adverse health effects can be serious, and in rare instances can be fatal, and there are, in addition, related socioeconomic issues. The challenges that chemical respiratory allergy pose for toxicologists are substantial. No validated methods are available for hazard identification and characterisation, and this is due in large part to the fact that there remains considerable uncertainty and debate about the mechanisms through which sensitisation of the respiratory tract is acquired. Despite that uncertainty, there is a need to establish some common understanding of the key events and processes that are involved in respiratory sensitisation to chemicals and that might in turn provide the foundations for novel approaches to safety assessment. In recent years the concept of adverse outcome pathways (AOP) has gained some considerable interest among the toxicology community as a basis for outlining the key steps leading to an adverse health outcome, while also providing a framework for focusing future research, and for developing alternative paradigms for hazard characterisation. Here we explore application of the same general principles to an examination of the induction by chemicals of respiratory sensitisation. In this instance, however, we have chosen to adopt a reverse engineering approach and to model a possible AOP for chemical respiratory allergy working backwards from the elicitation of adverse health effects to the cellular and molecular mechanisms that are implicated in the acquisition of sensitisation

  14. Catalyst for microelectromechanical systems microreactors

    Energy Technology Data Exchange (ETDEWEB)

    Morse, Jeffrey D. (Martinez, CA); Sopchak, David A. (Livermore, CA); Upadhye, Ravindra S. (Pleasanton, CA); Reynolds, John G. (San Ramon, CA); Satcher, Joseph H. (Patterson, CA); Gash, Alex E. (Brentwood, CA)

    2011-11-15

    A microreactor comprising a silicon wafer, a multiplicity of microchannels in the silicon wafer, and a catalyst coating the microchannels. In one embodiment the catalyst coating the microchannels comprises a nanostructured material. In another embodiment the catalyst coating the microchannels comprises an aerogel. In another embodiment the catalyst coating the microchannels comprises a solgel. In another embodiment the catalyst coating the microchannels comprises carbon nanotubes.

  15. Catalyst for microelectromechanical systems microreactors

    Science.gov (United States)

    Morse, Jeffrey D.; Sopchak, David A.; Upadhye, Ravindra S.; Reynolds, John G.; Satcher, Joseph H.; Gash, Alex E.

    2010-06-29

    A microreactor comprising a silicon wafer, a multiplicity of microchannels in the silicon wafer, and a catalyst coating the microchannels. In one embodiment the catalyst coating the microchannels comprises a nanostructured material. In another embodiment the catalyst coating the microchannels comprises an aerogel. In another embodiment the catalyst coating the microchannels comprises a solgel. In another embodiment the catalyst coating the microchannels comprises carbon nanotubes.

  16. CFD (Computational Fluid Dynamics) simulators and thermal cracking of heavy oil and ultraheavy residues using microreactor

    Energy Technology Data Exchange (ETDEWEB)

    Jardini, Andre L.; Bineli, Aulus R.R.; Viadana, Adriana M.; Maciel, Maria Regina Wolf; Maciel Filho, Rubens [State University of Campinas (UNICAMP), SP (Brazil). School of Chemical Engineering; Medina, Lilian C.; Gomes, Alexandre de O. [PETROBRAS S.A., Rio de Janeiro, RJ (Brazil). Centro de Pesquisas (CENPES); Barros, Ricardo S. [University Foundation Jose Bonifacio (FUJB), Rio de Janeiro, RJ (Brazil)

    2008-07-01

    In this paper, the design of microreactor with microfluidics channels has been carried out in Computer Aided Design Software (CAD) and constructed in rapid prototyping system to be used in chemical reaction processing of the heavy oil fractions. The flow pattern properties of microreactor (fluid dynamics, mixing behavior) have been considered through CFD (computational fluid dynamics) simulations. CFD calculations are also used to study the design and specification of new microreactor developments. The potential advantages of using a microreactor include better control of reaction conditions, improved safety and portability. A more detailed crude assay of the raw national oil, whose importance was evidenced by PETROBRAS/CENPES allows establishing the optimum strategies and processing conditions, aiming at a maximum utilization of the heavy oil fractions, towards valuable products. These residues are able to be processed in microreactor, in which conventional process like as hydrotreating, catalytic and thermal cracking may be carried out in a much more intensified fashion. The whole process development involves a prior thermal study to define the possible operating conditions for a particular task, the microreactor design through computational fluid dynamics and construction using rapid prototyping. This gives high flexibility for process development, shorter time, and costumer/task oriented process/product development. (author)

  17. Three Phase Catalytic Hydrogenation in Falling Film Microreactor

    Czech Academy of Sciences Publication Activity Database

    Stavárek, Petr; de Bellefon, C.

    Praha : Process Engineering Publisher, 2010, s. 289. ISBN 978-80-02-02246-6. [International Congress of Chemical and Process Engineering CHISA 2010 /19./ - European Congress of Chemical Engineering ECCE-7 /7./. Prague (CZ), 28.08.2010-01.09.2010] Grant ostatní: IMPULSE(XE) NMP2/CT/2005/011816 Institutional research plan: CEZ:AV0Z40720504 Keywords : falling film * microreactor * catalytic hydrogenation Subject RIV: CI - Industrial Chemistry, Chemical Engineering www.chisa.cz/2010, www.ecce7.com

  18. Oxidation of Volatile Organic Compounds in a Multifunctional High Temperature and High-Pressure Cassette Microreactor

    Czech Academy of Sciences Publication Activity Database

    Vajglová, Zuzana; Stavárek, Petr; Křišťál, Jiří; Jirátová, Květa; Ludvíková, Jana; Jiřičný, Vladimír

    Praha: Orgit, 2013 - (Kalenda, P.; Lubojacký, J.), 325-332 ISBN 978-80-86238-55-5. [International Conference on Chemical Technology (ICCT 2013) /1./. Mikulov (CZ), 08.04.2013-10.04.2013] Institutional support: RVO:67985858 Keywords : high-temperature application * microreactor * catalytic oxidation Subject RIV: CI - Industrial Chemistry, Chemical Engineering

  19. Hydrogenation of Aliphatic Alkenes in a High-Temperature High-Pressure Packed-Bed Microreactor

    Czech Academy of Sciences Publication Activity Database

    Stavárek, Petr; Vajglová, Zuzana; Křišťál, Jiří; Herbstritt, F.; Heck, J.; Jiřičný, Vladimír

    Praha : Orgit, 2012, P1.164. ISBN 978-80-905035-1-9. [International Congress of Chemical and Process Engineering CHISA 2012 and 15th Conference PRES 2012 /20./. Prague (CZ), 25.08.2012-29.08.2012] Institutional support: RVO:67985858 Keywords : microreactor * hydrogenation reactions * aliphatic alkenes Subject RIV: CI - Industrial Chemistry, Chemical Engineering www.chisa.cz/2012

  20. Hydrodynamic and Heat Transfer Model of a Gas-Liquid Microreactor

    Czech Academy of Sciences Publication Activity Database

    Křišťál, Jiří; Stavárek, Petr; Staněk, Vladimír; Jiřičný, Vladimír; Simoncelli, A.; Vanhoutte, D.; Tarchini, R.; Talford, M.; Hass-Santo, K.; Benzinger, W.

    Praha : Orgit, 2012, P7.7. ISBN 978-80-905035-1-9. [International Congress of Chemical and Process Engineering CHISA 2012 and 15th Conference PRES 2012 /20./. Prague (CZ), 25.08.2012-29.08.2012] Institutional support: RVO:67985858 Keywords : microreactor * gas-liquid reaction * transfer model Subject RIV: CI - Industrial Chemistry, Chemical Engineering www.chisa.cz/2012

  1. The development of flow-through bio-catalyst microreactors from silica micro structured fibers for lipid transformations.

    Science.gov (United States)

    Anuar, Sabiqah Tuan; Villegas, Carla; Mugo, Samuel M; Curtis, Jonathan M

    2011-06-01

    This study demonstrates the utility of a flow-through enzyme immobilized silica microreactor for lipid transformations. A silica micro structured fiber (MSF) consisting of 168 channels of internal diameter 4-5 μm provided a large surface area for the covalent immobilization of Candida antartica lipase. The specific activity of the immobilized lipase was determined by hydrolysis of p-nitrophenyl butyrate and calculated to be 0.81 U/mg. The catalytic performance of the lipase microreactor was demonstrated by the efficient ethanolysis of canola oil. The parameters affecting the performance of the MSF microreactor, including temperature and reaction flow rate, were investigated. Characterization of the lipid products exiting the microreactor was performed by non-aqueous reversed-phased liquid chromatography (NARP-LC) with evaporative light scattering detector (ELSD) and by comprehensive two-dimensional gas chromatography (GC x GC). Under optimized conditions of 1 μL/min flow rate of 5 mg/mL trioleoylglycerol (TO) in ethanol and 50 °C reaction temperature, 2-monooleoylglycerol was the main product at > 90% reaction yield. The regioselectivity of the Candida antartica lipase immobilized MSF microreactor in the presence of ethanol was found to be comparable to that obtained under conventional conditions. The ability of these reusable flow-through microreactors to regioselectively form monoacylglycerides in high yield from triacylglycerides demonstrate their potential use in small-scale lipid transformations or analytical lipids profiling. PMID:21318469

  2. Fluorine-18 chemistry in micro-reactors

    OpenAIRE

    Lu, Shuiyu; Chun, Joong-Hyun; Pike, Victor W.

    2010-01-01

    Recent applications of micro-reactor (microfluidics) technology to radiofluorination chemistry within our laboratory are presented, based on use of either a simple T-shaped glass micro-reactor or a more advanced microfluidics instrument. The topics include reaction optimization and radioligand production, in particular the study of the radiofluorination of diaryliodonium salts, [18F]fluoride ion exchange with xenon difluoride, esterification with [18F]2-fluoroethyl tosylate, and the syntheses...

  3. Practical Engineering Aspects of Catalysis in Microreactors

    OpenAIRE

    Křišťál, J. (Jiří); Stavárek, P. (Petr); Vajglová, Z. (Zuzana); Vondráčková, M. (Magdalena); Pavlorková, J. (Jana); Jiřičný, V. (Vladimír)

    2015-01-01

    This work presents a brief review of microreactor applications for different types of catalytic reactions. Practical aspects of four selected case studies are discussed in detail: enzymatic glycerolysis, hydrogenation of isobutene, stereoselective catalytic transfer hydrogenation and photochemical oxidation of 4-chlorophenol. The common benefits resulting from the use of microreactors are documented, and include the excellent control of operating condition, efficient heat transfer, tailored d...

  4. Hydrogenation of Isobutene in Fixed Bed Microreactor - Long Term Experiments

    Czech Academy of Sciences Publication Activity Database

    Vajglová, Zuzana; Stavárek, Petr; Křišťál, Jiří; Kolena, J.; Jiřičný, Vladimír

    Prague : Czech Society of Industrial Chemistry, 2014 - (Kalenda, P.; Lubojacký, J.), s. 58-62 ISBN 978-80-86238-64-7. [mezinárodní chemicko-technologická konference /2./. Mikulov (CZ), 07.04.2014-09.04.2014] Grant ostatní: UniCRE(XE) CZ.1.05/2.1.00/03.0071 Institutional support: RVO:67985858 Keywords : hydrogenation of isobutene * fixed bed microreactor * long-term experiments Subject RIV: CI - Industrial Chemistry, Chemical Engineering http://www.icct.cz

  5. Multichannel quench-flow microreactor chip for parallel reaction monitoring.

    Science.gov (United States)

    Bula, Wojciech P; Verboom, Willem; Reinhoudt, David N; Gardeniers, Han J G E

    2007-12-01

    This paper describes a multichannel silicon-glass microreactor which has been utilized to investigate the kinetics of a Knoevenagel condensation reaction under different reaction conditions. The reaction is performed on the chip in four parallel channels under identical conditions but with different residence times. A special topology of the reaction coils overcomes the common problem arising from the difference in pressure drop of parallel channels having different length. The parallelization of reaction coils combined with chemical quenching at specific locations results in a considerable reduction in experimental effort and cost. The system was tested and showed good reproducibility in flow properties and reaction kinetic data generation. PMID:18030392

  6. Photochemical Degradation of Polybrominated Diphenyl Ethers in Microreactor

    Czech Academy of Sciences Publication Activity Database

    Vajglová, Zuzana; Veselý, M.; Hejda, S.; Vondráčková, Magdalena; Křišťál, Jiří; Cajthaml, Tomáš; Křesinová, Zdena; Tříska, Jan; Klusoň, Petr; Jiřičný, Vladimír

    2015-01-01

    Roč. 41, č. 12 (2015), s. 9373-9381. ISSN 0922-6168. [Pannonian Symposium on Catalysis /12./. Castle Trest, 16.09.2014-20.09.2014] R&D Projects: GA ČR(CZ) GAP105/12/0664; GA ČR GA104/09/0880 Institutional support: RVO:67985858 ; RVO:61388971 ; RVO:67179843 Keywords : polybrominated diphenyl ethers * photochemical microreactor * debromination * photo degradation Subject RIV: CI - Industrial Chemistry, Chemical Engineering; EH - Ecology, Behaviour (UEK-B) Impact factor: 1.221, year: 2014

  7. Integrated calorimetric microreactor in low-temperature cofired ceramic (LTCC) technology

    OpenAIRE

    Maeder, Thomas; Willigens, Raphaël; Fournier, Yannick; Ryser, Peter

    2006-01-01

    Object of this work 1) Explore the feasibility of an LTCC microreactorChemical stability: compatible with HCl, NaOH, ... • Thermal stability to >100°C 2) Achieve a high degree of integration • Temperature measurement • Reactant flow measurement • Temperature control • Calorimetric chamber

  8. Combined Effect of Temperature and Dissolved Oxygen on Degradation of 4-chlorophenol in Photo Microreactor

    Czech Academy of Sciences Publication Activity Database

    Vondráčková, Magdalena; Hejda, S.; Stavárek, Petr; Křišťál, Jiří; Klusoň, Petr

    2015-01-01

    Roč. 94, SI (2015), s. 35-38. ISSN 0255-2701 R&D Projects: GA ČR(CZ) GAP105/12/0664 Institutional support: RVO:67985858 Keywords : photo microreactor * phthalocyanine * chlorophenol oxidation Subject RIV: CI - Industrial Chemistry, Chemical Engineering Impact factor: 2.071, year: 2014

  9. Two-Phase Pressure Drop in Thin-Gap Microreactor with Electrochemically Generated Bubbles

    Czech Academy of Sciences Publication Activity Database

    Křišťál, Jiří; Havlica, Jaromír; Jiřičný, Vladimír

    - : DECHEMA e.V, 2006, s. 277-278. [International Conferences on Microreaction Technology IMRET 9 /9./. Potsdam/Berlin (DE), 06.09.2006-08.09.2006] Institutional research plan: CEZ:AV0Z40720504 Keywords : thin-gap * microreactor * pressure drop Subject RIV: CI - Industrial Chemistry, Chemical Engineering

  10. Methyl Chloride Synthesis in a Microreactor-Development of a Small Scale Production Unit

    Czech Academy of Sciences Publication Activity Database

    Schmidt, S.A.; Wärnå, J.; Vajglová, Zuzana; Kumar, N.; Eränen, K.; Murzin, D.Yu.; Salmi, T.

    Budapest : Budapest University of Technology and Economics , 2014, s. 57-58. ISBN 978-963-05-9518-6. [International Conference on Microreactor Technology IMRET /13./. Budapest (HU), 23.06.2014-25.06.2014] Institutional support: RVO:67985858 Keywords : methyl chloride * chloromethane * on-site production Subject RIV: CI - Industrial Chemistry, Chemical Engineering

  11. Reversible targeting of noncatalytic cysteines with chemically tuned electrophiles

    DEFF Research Database (Denmark)

    Serafimova, Iana M; Pufall, Miles A; Krishnan, Shyam;

    2012-01-01

    Targeting noncatalytic cysteine residues with irreversible acrylamide-based inhibitors is a powerful approach for enhancing pharmacological potency and selectivity. Nevertheless, concerns about off-target modification motivate the development of reversible cysteine-targeting strategies. Here we...... show that electron-deficient olefins, including acrylamides, can be tuned to react with cysteine thiols in a rapidly reversible manner. Installation of a nitrile group increased the olefins' intrinsic reactivity, but, paradoxically, eliminated the formation of irreversible adducts. Incorporation of...... targeted cysteine. Disruption of these interactions by protein unfolding or proteolysis promoted instantaneous cleavage of the covalent bond. Our results establish a chemistry-based framework for engineering sustained covalent inhibition without accumulating permanently modified proteins and peptides....

  12. Conceptual design of a mass parallelized PEF microreactor

    NARCIS (Netherlands)

    Fox, M.B.; Esveld, D.C.; Boom, R.M.

    2007-01-01

    This article describes the conceptual design of a mass parallelized pulsed electric field (PEF) microreactor, where microorganisms are inactivated by short, high electric field pulses. Since the advantages of a PEF microreactor are related to the small size, the throughput of a microreactor can only

  13. Microreactor-Assisted Solution Deposition for Compound Semiconductor Thin Films

    Directory of Open Access Journals (Sweden)

    Chang-Ho Choi

    2014-05-01

    Full Text Available State-of-the-art techniques for the fabrication of compound semiconductors are mostly vacuum-based physical vapor or chemical vapor deposition processes. These vacuum-based techniques typically operate at high temperatures and normally require higher capital costs. Solution-based techniques offer opportunities to fabricate compound semiconductors at lower temperatures and lower capital costs. Among many solution-based deposition processes, chemical bath deposition is an attractive technique for depositing semiconductor films, owing to its low temperature, low cost and large area deposition capability. Chemical bath deposition processes are mainly performed using batch reactors, where all reactants are fed into the reactor simultaneously and products are removed after the processing is finished. Consequently, reaction selectivity is difficult, which can lead to unwanted secondary reactions. Microreactor-assisted solution deposition processes can overcome this limitation by producing short-life molecular intermediates used for heterogeneous thin film synthesis and quenching the reaction prior to homogeneous reactions. In this paper, we present progress in the synthesis and deposition of semiconductor thin films with a focus on CdS using microreactor-assisted solution deposition and provide an overview of its prospect for scale-up.

  14. Microreactor Technology as an Efficient Tool for Multicomponent Reactions

    Science.gov (United States)

    Cukalovic, Ana; Monbaliu, Jean-Christophe M. R.; Stevens, Christian V.

    Multicomponent reactions are an important tool in organic synthesis as they often allow the circumvention of multistep procedures by combining three or more molecules into one structure in a single step. An additional asset of the approach is the significant increase of the combinatorial possibilities, since a modification of the final product is easily accomplished by implementing minor changes in the reaction setup; this obviously allows considerable savings in time and resources. These advantages are of particular interest in pharmaceutical research for the construction of libraries. In order to increase the sustainability of chemical processes, the field is intensively explored, and novel reactions are frequently reported. Microreactor technology also offers a contemporary way of conducting chemical reactions in a more sustainable fashion due to the miniaturization and increased safety, and also in a technically improved manner due to intensified process efficiency. This relatively new technology is implemented in novel and improved applications and is getting more and more used in chemical research. The combination of the benefits from the two approaches clearly presents an attractive reaction design, and this chapter presents an overview of the reported examples in which the microreactor technology and the multicomponent approach are combined, usually with dramatically improved results compared to those previously reported.

  15. Silver nanocluster catalytic microreactors for water purification

    Science.gov (United States)

    Da Silva, B.; Habibi, M.; Ognier, S.; Schelcher, G.; Mostafavi-Amjad, J.; Khalesifard, H. R. M.; Tatoulian, M.; Bonn, D.

    2016-07-01

    A new method for the elaboration of a novel type of catalytic microsystem with a high specific area catalyst is developed. A silver nanocluster catalytic microreactor was elaborated by doping a soda-lime glass with a silver salt. By applying a high power laser beam to the glass, silver nanoclusters are obtained at one of the surfaces which were characterized by BET measurements and AFM. A microfluidic chip was obtained by sealing the silver coated glass with a NOA 81 microchannel. The catalytic activity of the silver nanoclusters was then tested for the efficiency of water purification by using catalytic ozonation to oxidize an organic pollutant. The silver nanoclusters were found to be very stable in the microreactor and efficiently oxidized the pollutant, in spite of the very short residence times in the microchannel. This opens the way to study catalytic reactions in microchannels without the need of introducing the catalyst as a powder or manufacturing complex packed bed microreactors.

  16. The Intelligent Properties of Micro-reactors for Preparating Nanoparticles

    Institute of Scientific and Technical Information of China (English)

    Gang WEI; Hai Yan HUANG; Rong Chun XIONG

    2003-01-01

    TiO2 nanoparticles were synthesized by using micro-reactors. The shape and size of the nanoparticles produced from the original micro-reactors and the five times recycled micro-reactors mother liquor were investigated on transmission electron microscopy (TEM) by using the original sample, freeze prepared sample, and dyeing treated sample, respectively. UV-VIS spectrometry was used to study the growth process of TiO2 nanoparticles in main reactors. The results showed that micro-reactors with nanometer magnitude had spherical or oval structures, and could restore to their original structure after they were destroyed. The products prepared in the original micro-reactors were similar to that in the micro-reactors recycled for many times, suggesting that the micro-reactors had memory function.

  17. Patterning of colloidal particles in the galvanic microreactor

    Science.gov (United States)

    Jan, Linda

    situ, it is shown that particle cementation coincides with the precipitation and deposition of reaction products. The precipitation process is caused by shifts in the chemical equilibria of the microreactor due to changes in the composition of the electrolyte during the reactions, which can be used to control particle cementation. The corrosion driven transport, deposition and adherence of colloidal particles at corrosion sites have implications for the development of autonomous self-healing materials.

  18. Self-Sustained Oscillations of Temperature and Conversion in a Packed Bed Microreactor during 2-Methylpropene (Isobutene) Hydrogenation

    Czech Academy of Sciences Publication Activity Database

    Stavárek, Petr; Vajglová, Zuzana; Křišťál, Jiří; Jiřičný, Vladimír; Kolena, J.

    2015-01-01

    Roč. 256, NOV 1 (2015), s. 250-260. ISSN 0920-5861. [InternationalCongress of Chemical and Process Engineering CHISA 2014 /21./. Prague, 23.08.2014-27.08.2014] Institutional support: RVO:67985858 Keywords : hydrogenation * microreactor * oscillation Subject RIV: CI - Industrial Chemistry, Chemical Engineering Impact factor: 3.893, year: 2014

  19. Continuously operated falling film microreactor for selective hydrogenation of carbon-carbon triple bonds

    OpenAIRE

    Rehm, Thomas H.; Berguerand, Charline; Ek, Satu; Zapf, Ralf; Löb, Patrick; Nikoshvili, Linda; Kiwi-Minsker, Lioubov

    2016-01-01

    Despite significant advances in the fabrication and applications of microreactors for production of chemicals, their use for catalytic reactions remains a challenge, especially in fine chemical synthesis where the selectivity towards the desired product is an issue. A falling film microstructured reactor (FFMR) was tested in the selective hydrogenation of 2-butyne-1,4-diol (1) to its olefinic derivative (2). The FFMR plates were coated with Al2O3 or ZnO followed by the deposition of Pd nanopa...

  20. Influence of Dissolved Oxygen on Degradation of 4-Chlorophenol in Photo Microreactor

    Czech Academy of Sciences Publication Activity Database

    Drhová, Magdalena; Hejda, S.; Klusoň, Petr; Křišťál, Jiří

    Prague: Orgit, 2014, s. 106. ISBN 978-80-02-02555-9. [International Congress of Chemical and Process Engineering /21./ - CHISA 2014 and Conference on Process Integration, Modelling and Optimisation for Energy Saving and Pollution Reduction /17./ - PRES 2014. Prague (CZ), 23.08.2014-27.08.2014] Institutional support: RVO:67985858 Keywords : microreactor * photocatalyzed reactions * reactive singlet oxygen Subject RIV: CI - Industrial Chemistry, Chemical Engineering

  1. Alcohol Ethoxylate Sulfation in a Microreactor Operated in a Pilot Plant Environment

    Czech Academy of Sciences Publication Activity Database

    Stavárek, Petr; Křišťál, Jiří; Jiřičný, Vladimír; Vanhoutte, D.; Tarchini, R.

    Prague: Orgit, 2014, s. 72. ISBN 978-80-02-02555-9. [International Congress of Chemical and Process Engineering /21./ - CHISA 2014 and Conference on Process Integration, Modelling and Optimisation for Energy Saving and Pollution Reduction /17./ - PRES 2014. Prague (CZ), 23.08.2014-27.08.2014] EU Projects: European Commission(XE) 228867 - F³ FACTORY Institutional support: RVO:67985858 Keywords : microreactor * sulfation * capillaries Subject RIV: CI - Industrial Chemistry, Chemical Engineering

  2. Kinetics and Rate Law Determination of 2-Methylpropene Hydrogenation in a Packed-Bed Microreactor

    Czech Academy of Sciences Publication Activity Database

    Vajglová, Zuzana; Stavárek, Petr; Křišťál, Jiří; Kolena, J.; Jiřičný, Vladimír

    Prague: Orgit, 2014, s. 87. ISBN 978-80-02-02555-9. [International Congress of Chemical and Process Engineering /21./ - CHISA 2014 and Conference on Process Integration, Modelling and Optimisation for Energy Saving and Pollution Reduction /17./ - PRES 2014. Prague (CZ), 23.08.2014-27.08.2014] Institutional support: RVO:67985858 Keywords : fluid catalytic cracking * hydrogenation * microreactor Subject RIV: CI - Industrial Chemistry, Chemical Engineering

  3. On the graph and systems analysis of reversible chemical reaction networks with mass action kinetics

    NARCIS (Netherlands)

    Rao, Shodhan; Jayawardhana, Bayu; Schaft, Arjan van der

    2012-01-01

    Motivated by the recent progresses on the interplay between the graph theory and systems theory, we revisit the analysis of reversible chemical reaction networks described by mass action kinetics by reformulating it using the graph knowledge of the underlying networks. Based on this formulation, we

  4. Design and fabrication of miniaturized PEM fuel cell combined microreactor with self-regulated hydrogen mechanism

    Science.gov (United States)

    Balakrishnan, A.; Frei, M.; Kerzenmacher, S.; Reinecke, H.; Mueller, C.

    2015-12-01

    In this work we present the design and fabrication of the miniaturized PEM fuel cell combined microreactor system with hydrogen regulation mechanism and testing of prototype microreactor. The system consists of two components (i) fuel cell component and (ii) microreactor component. The fuel cell component represents the miniaturized PEM fuel cell system (combination of screen printed fuel cell assembly and an on-board hydrogen storage medium). Hydrogen production based on catalytic hydrolysis of chemical hydride takes place in the microreactor component. The self-regulated hydrogen mechanism based on the gaseous hydrogen produced from the catalytic hydrolysis of sodium borohydride (NaBH4) gets accumulated as bubbles at the vicinity of the hydrophobic coated hydrogen exhaust holes. When the built up hydrogen bubbles pressure exceeds the burst pressure at the hydrogen exhaust holes the bubble collapses. This collapse causes a surge of fresh NaBH4 solution onto the catalyst surface leading to the removal of the reaction by-products formed at the active sites of the catalyst. The catalyst used in the system is platinum deposited on a base substrate. Nickel foam, carbon porous medium (CPM) and ceramic plate were selected as candidates for base substrate for developing a robust catalyst surface. For the first time the platinum layer fabricated by pulsed electrodeposition and dealloying (EPDD) technique is used for hydrolysis of NaBH4. The major advantages of such platinum catalyst layers are its high surface area and their mechanical stability. Prototype microreactor system with self-regulated hydrogen mechanism is demonstrated.

  5. Silicon microreactors for measurements of catalytic activity

    DEFF Research Database (Denmark)

    Henriksen, Toke Riishøj

    reactors consist of a microchannel system etched in an oxidized silicon chip and sealed with a glass lid using anodic bonding. The chip design relies on a gas flow through the channel system and is designed for reactions at pressures at the order of 1 bar. A high sensitivity is obtained by directing the...... has been employed as a test reaction. Using temperature ramping, it has been found that platinum catalysts with areas as small as 15μm2 are conveniently characterized with the device. A setup for locally cooled anodic bonding of microreactors is presented. The aim with this setup is to avoid catalyst...... deactivation in the reactor during bonding. A finite element analysis has been carried out to investigate the temperature distribution during bonding in a microreactor. The analysis suggests that the setup can effectively keep the reaction chamber temperature below 50 ◦C while the rest of the chip bonds. This...

  6. Photosensitized Oxygenations of Hexamethylbenzene in Phase Contact Enhanced Microreactor

    Energy Technology Data Exchange (ETDEWEB)

    Park, Chan Yi; Park, Jeong Hyeon; Lim Hyo Jin; Hwang, Geumsook; Park, Chan Pil [Chungnam National Univ., Daejeon (Korea, Republic of)

    2014-04-15

    Activated singlet oxygen ({sup 1}O{sub 2}) has successfully been utilized in production of various compounds including fragrances, pharmaceuticals, and fine chemicals. However, the traditional reaction required a prolonged reaction time due to the difficulty of introducing adequate light and oxygen into the solution. Low contact probability between four species of oxygen, photosensitizer, light, and reagent is an inherent drawback of the traditional photoreaction. Molecular diffusion distance is the most important factor in the heterogeneous reactions including gas-liquid, gassolid, liquid-solid, and immiscible liquid-liquid. Therefore, rates of reaction are closely depended on the distance. Microreactor has provided a distinct advantage in the short molecular diffusion distance due to the high surface-to-volume ratio driven by narrow fluidic channels.

  7. Synthesis of copper nanocolloids using a continuous flow based microreactor

    Science.gov (United States)

    Xu, Lei; Peng, Jinhui; Srinivasakannan, C.; Chen, Guo; Shen, Amy Q.

    2015-11-01

    The copper (Cu) nanocolloids were prepared by sodium borohydride (NaBH4) reduction of metal salt solutions in a T-shaped microreactor at room temperature. The influence of NaBH4 molar concentrations on copper particle's diameter, morphology, size distribution, and elemental compositions has been investigated by transmission electron microscopy (TEM) and X-ray diffraction (XRD). The ultraviolet-visible spectroscopy (UV-vis) was used to verify the chemical compounds of nanocolloids and estimate the average size of copper nanocolloids. The synthesized copper nanocolloids were uniform in size and non-oxidized. A decrease in the mean diameter of copper nanocolloids was observed with increasing NaBH4 molar concentrations. The maximum mean diameter (4.25 nm) occurred at the CuSO4/NaBH4 molar concentration ratio of 1:2.

  8. Photosensitized Oxygenations of Hexamethylbenzene in Phase Contact Enhanced Microreactor

    International Nuclear Information System (INIS)

    Activated singlet oxygen (1O2) has successfully been utilized in production of various compounds including fragrances, pharmaceuticals, and fine chemicals. However, the traditional reaction required a prolonged reaction time due to the difficulty of introducing adequate light and oxygen into the solution. Low contact probability between four species of oxygen, photosensitizer, light, and reagent is an inherent drawback of the traditional photoreaction. Molecular diffusion distance is the most important factor in the heterogeneous reactions including gas-liquid, gassolid, liquid-solid, and immiscible liquid-liquid. Therefore, rates of reaction are closely depended on the distance. Microreactor has provided a distinct advantage in the short molecular diffusion distance due to the high surface-to-volume ratio driven by narrow fluidic channels

  9. Effect of Operating Pressure and Electrode Surface Roughness on Gas-Liquid Flow Patterns in Thin-Gap Electrochemical Microreactor

    Czech Academy of Sciences Publication Activity Database

    Křišťál, Jiří; Stavárek, Petr; Záloha, Petr; Jiřičný, Vladimír

    Prague: ICPF ASCR, 2013. s. 61. ISBN N. [Workshop on Smart and Green Interfaces 2013. 20.3.2013-22.03.2013, Prague] Grant ostatní: COST(XE) MP1106 Institutional support: RVO:67985858 Keywords : bubbles * experimental investigation * microreactor Subject RIV: CI - Industrial Chemistry, Chemical Engineering

  10. Effect of Operating Pressure and Electrode Surface Roughness on Gas-Liquid Flow Patterns in Thin-Gap Electrochemical Microreactor

    Czech Academy of Sciences Publication Activity Database

    Křišťál, Jiří; Stavárek, Petr; Záloha, Petr; Jiřičný, Vladimír

    Prague : ICPF ASCR, 2013. s. 61. ISBN N. [Workshop on Smart and Green Interfaces 2013. 20.3.2013-22.03.2013, Prague] Grant ostatní: COST(XE) MP1106 Institutional support: RVO:67985858 Keywords : bubbles * experimental investigation * microreactor Subject RIV: CI - Industrial Chemistry, Chemical Engineering

  11. Effects of reversible chemical reaction on Li diffusion and stresses in spherical composition-gradient electrodes

    International Nuclear Information System (INIS)

    Composition-gradient electrode materials have been proven to be one of the most promising materials in lithium-ion battery. To study the mechanism of mechanical degradation in spherical composition-gradient electrodes, the finite deformation theory and reversible chemical theory are adopted. In homogeneous electrodes, reversible electrochemical reaction may increase the magnitudes of stresses. However, reversible electrochemical reaction has different influences on stresses in composition-gradient electrodes, resulting from three main inhomogeneous factors—forward reaction rate, backward reaction rate, and reaction partial molar volume. The decreasing transition form of forward reaction rate, increasing transition form of backward reaction rate, and increasing transition form of reaction partial molar volume can reduce the magnitudes of stresses. As a result, capacity fading and mechanical degradation are reduced by taking advantage of the effects of inhomogeneous factors

  12. Synthetically chemical-electrical mechanism for controlling large scale reversible deformation of liquid metal objects

    Science.gov (United States)

    Zhang, Jie; Sheng, Lei; Liu, Jing

    2014-11-01

    Reversible deformation of a machine holds enormous promise across many scientific areas ranging from mechanical engineering to applied physics. So far, such capabilities are still hard to achieve through conventional rigid materials or depending mainly on elastomeric materials, which however own rather limited performances and require complicated manipulations. Here, we show a basic strategy which is fundamentally different from the existing ones to realize large scale reversible deformation through controlling the working materials via the synthetically chemical-electrical mechanism (SCHEME). Such activity incorporates an object of liquid metal gallium whose surface area could spread up to five times of its original size and vice versa under low energy consumption. Particularly, the alterable surface tension based on combination of chemical dissolution and electrochemical oxidation is ascribed to the reversible shape transformation, which works much more flexible than many former deformation principles through converting electrical energy into mechanical movement. A series of very unusual phenomena regarding the reversible configurational shifts are disclosed with dominant factors clarified. This study opens a generalized way to combine the liquid metal serving as shape-variable element with the SCHEME to compose functional soft machines, which implies huge potential for developing future smart robots to fulfill various complicated tasks.

  13. A comparison of reversible chemical reactions for solar thermochemical power generation

    OpenAIRE

    Williams, O. M.

    1980-01-01

    Reversible chemical reactions operating in a thermochemical energy transfer system have been proposed for solar electricity generation in order to solve not only the problem of energy transport from the solar collection field to a central power plant, but also potentially the long term lossless energy storage problem through underground storage of the reaction products. A number of reactions have been proposed for solar thermochemical power generation and in this paper the thermodynamic and c...

  14. On the graph and systems analysis of reversible chemical reaction networks with mass action kinetics

    OpenAIRE

    Rao, Shodhan; Jayawardhana, Bayu; der Schaft, Arjan van

    2012-01-01

    Motivated by the recent progresses on the interplay between the graph theory and systems theory, we revisit the analysis of reversible chemical reaction networks described by mass action kinetics by reformulating it using the graph knowledge of the underlying networks. Based on this formulation, we can characterize the space of equilibrium points and provide simple dynamical analysis on the state space modulo the space of equilibrium points.

  15. Effect of diffusion on enzyme activity in a microreactor

    NARCIS (Netherlands)

    Swarts, J.W.; Kolfschoten, R.C.; Jansen, M.C.A.A.; Janssen, A.E.M.; Boom, R.M.

    2010-01-01

    To establish general rules for setting up an enzyme microreactor system, we studied the effect of diffusion on enzyme activity in a microreactor. As a model system we used the hydrolysis of ortho-nitrophenyl-ß-d-galactopyranoside by ß-galactosidase from Kluyveromyces lactis. We found that the Michae

  16. Surface Modification for Microreactor Fabrication

    OpenAIRE

    Wladyslaw Torbicz; Jerzy Kruk; Konrad Dudziński; Roberto Canteri; Michele Vendano; Lorenzo Lunelli; Cecilia Pederzolli; Elżbieta Remiszewska; Pijanowska, Dorota G.

    2006-01-01

    In this paper, methods of surface modification of different supports, i.e. glass and polymeric beads for enzyme immobilisation are described. The developed method of enzyme immobilisation is based on Schiff's base formation between the amino groups on the enzyme surface and the aldehyde groups on the chemically modified surface of the supports. The surface of silicon modified by APTS and GOPS with immobilised enzyme was characterised by atomic force microscopy (AFM), time-of-flight secondary ...

  17. Model-Based Design of Biochemical Microreactors.

    Science.gov (United States)

    Elbinger, Tobias; Gahn, Markus; Neuss-Radu, Maria; Hante, Falk M; Voll, Lars M; Leugering, Günter; Knabner, Peter

    2016-01-01

    Mathematical modeling of biochemical pathways is an important resource in Synthetic Biology, as the predictive power of simulating synthetic pathways represents an important step in the design of synthetic metabolons. In this paper, we are concerned with the mathematical modeling, simulation, and optimization of metabolic processes in biochemical microreactors able to carry out enzymatic reactions and to exchange metabolites with their surrounding medium. The results of the reported modeling approach are incorporated in the design of the first microreactor prototypes that are under construction. These microreactors consist of compartments separated by membranes carrying specific transporters for the input of substrates and export of products. Inside the compartments of the reactor multienzyme complexes assembled on nano-beads by peptide adapters are used to carry out metabolic reactions. The spatially resolved mathematical model describing the ongoing processes consists of a system of diffusion equations together with boundary and initial conditions. The boundary conditions model the exchange of metabolites with the neighboring compartments and the reactions at the surface of the nano-beads carrying the multienzyme complexes. Efficient and accurate approaches for numerical simulation of the mathematical model and for optimal design of the microreactor are developed. As a proof-of-concept scenario, a synthetic pathway for the conversion of sucrose to glucose-6-phosphate (G6P) was chosen. In this context, the mathematical model is employed to compute the spatio-temporal distributions of the metabolite concentrations, as well as application relevant quantities like the outflow rate of G6P. These computations are performed for different scenarios, where the number of beads as well as their loading capacity are varied. The computed metabolite distributions show spatial patterns, which differ for different experimental arrangements. Furthermore, the total output of G6P

  18. Open Tubular Microreactor with Enzyme Functionalized Micro- fluidic Channel for Amperometric Detection of Glucose

    Institute of Scientific and Technical Information of China (English)

    张蕾; 曲平; 盛金; 雷建平; 鞠烷先

    2012-01-01

    A simple and efficient method using enzyme immobilized microfluidic channel as open tubular microreactor was designed for amperometric detection of glucose. The microreactor was composed of a polydimethylsilicone/ glass hybrid device with three reservoirs, a cooling cave and a 6 cm capillary with a sampling fracture as micro-channel. The microchannel was further modified by thermal polymerization, followed by covalently attaching with glucose oxidase. Through fracture sampling and electrochromatography separation, the production via enzymatic reaction was determinated by Pt electrode at the end of capillary. The linear range for the detection of glucose was 0.05--7.5 mmol·L-1 with detection limit of 23μmol.L-1 The inter-and intra-chip reproducibilities for determination of 2.5 mmol-L-1 glucose were 98.5% (n=5) and 96.0% (n=5), respectively. With the advantage of flexible assembly, rapid efficiency, good stability and low-cost, this microreactor provided a potential platform for estab- lishing a portable enzyme-based chemical detection system in practical application.

  19. Microreactor Technology for On-Site Production of Methyl Chloride

    OpenAIRE

    Schmidt, S A.; Vajglová, Z. (Zuzana); Eränen, K.; Murzin, D.Y.; Salmi, T

    2014-01-01

    A reactor setup consisting of two stainless steel microreactors [gas-phase microreactor (GPMR)-mix from the Institut für Mikrotechnik Mainz (IMM)] coupled in series was used for production of methyl chloride by hydrochlorination of methanol. The catalyst was γ-alumina on microreactor platelets. The influence of temperature on the methanol conversion and methyl chloride selectivity was investigated. A maximum conversion of 97.6% and a selectivity of 98.8% were reached at 340°C, which is c...

  20. Microfluidic-based photocatalytic microreactor for environmental application: a review of fabrication substrates and techniques, and operating parameters.

    Science.gov (United States)

    Das, Susmita; Srivastava, Vimal Chandra

    2016-06-01

    Photochemical technology with microfluidics is emerging as a new platform in environmental science. Microfluidic technology has various advantages, like better mixing and a shorter diffusion distance for the reactants and products; and uniform distribution of light on the photocatalyst. Depending on the material type and related applications, several fabrication techniques have been adopted by various researchers. Microreactors have been prepared by various techniques, such as lithography, etching, mechanical microcutting technology, etc. Lithography can be classified into photolithography, soft lithography and X-ray lithography techniques whereas the etching process is divided into wet etching (chemical etching) and dry etching (plasma etching) techniques. Several substrates, like polymers, such as polydimethyl-siloxane (PDMS), polymethyle-methacrylate (PMMA), hydrogel, etc.; metals, such as stainless steel, titanium foil, etc.; glass, such as silica capillary, glass slide, etc.; and ceramics have been used for microchannel fabrication. During degradation in a microreactor, the degradation efficiency is affected by few important parameters such as flow rate, initial concentration of the target compound, microreactor dimensions, light intensity, photocatalyst structure and catalyst support. The present paper discusses and critically reviews fabrication techniques and substrates used for microchannel fabrication and critical operating parameters for organics, especially dye degradation in the microreactor. The kinetics of degradation has also been discussed. PMID:27193741

  1. Multilayered film microreactors fabricated by a one-step thermal bonding technique with high reproducibility and their applications.

    Science.gov (United States)

    Min, Kyoung-Ik; Kim, Jin-Oh; Kim, Heejin; Im, Do Jin; Kim, Dong-Pyo

    2016-03-21

    We report the versatile uses of multilayered polyimide (PI) film microreactors with various functions including pressure tolerance, three-dimensional mixing and multistep membrane emulsification. Such PI film microreactors were fabricated by a simple one-step thermal bonding technique with high reproducibility. Upon bonding at 300 °C for 1 hour, the thin and flexible film microdevices could withstand pressure up to 8.6 MPa and 16.3 MPa with PI adhesive film or fluoropolymer adhesive, respectively, due to differences in wettability. The hydrophilic and hydrophobic microchannel devices were used to generate monodisperse oil-in-water (O/W) and water-in-oil (W/O) droplets, and polymer micro/nanoparticles at a high generation frequency. A monolithic and chemical resistant film microreactor with a three-dimensional serpentine microchannel was used for the selective reduction of ester to aldehyde by efficient mixing and quenching in a flash chemistry manner, within a several 10(1) millisecond time scale. Furthermore, a novel multilayered film microreactor for organic-aqueous biphasic interfacial reactions was devised by embedding a membrane layer to induce chaotic mixing in both the interface and emulsified phase by flowing through multiple numbers of meshed structures along the hydrophobic channel. This simple and economic fabrication technique significantly facilitates mass production of multilayered film devices that could be useful as a platform for various microfluidic applications in chemistry and biology. PMID:26886679

  2. Characterization and modeling of multiphase flow in structured microreactors: a post microreactor case study.

    Science.gov (United States)

    Yang, Lu; Shi, Yanxiang; Abolhasani, Milad; Jensen, Klavs F

    2015-08-01

    We study microreactors with internal fields of posts as typical examples of structured microreactors to elucidate flow fields and their implications for mass transfer. Laser-induced fluorescence (LIF) visualization combined with image analysis is used to systematically quantify key features such as interfacial area, phase holdup and the characteristics of the post-wetting layer. The subsequent mass transport analysis yields insight into how the posts contribute to the overall enhanced mass transfer performance compared to open channels, and provides predictions of mass transfer performance under varying operating conditions. Computational fluid dynamic (CFD) simulations of multiphase flow using the volume-of-fluid (VOF) method are in good agreement with experimentally observed multiphase flows. PMID:26126496

  3. I: Hydrodynamic-focusing microreactor II: Mechanically interlocked molecules for functional materials

    Science.gov (United States)

    Coti, Karla Karina

    I: Microreactors, a class of microfluidics, offer numerous benefits -- such as small sample requirement, short analysis times and automations -- and have been used to study reactions of chemical and biological reagents. In order to understand the relationship between fast mixing, product regioselectivity, as well as the ability to separate, in time and space, the nanoparticle (NP) formation stages, a microreactor capable of fast and controllable mixing was developed (Chapter 1) based on multi-lamination and hydrodynamic-focusing. By taking advantage of the fast and controllable mixing properties of this novel microreactor one can control the time when chemical reactions commence inside the microchannels. These properties of the microreactor can be exploited to improve the product regioselectivity of a diazo-coupling reaction to attain a product distribution of monoazo to diazo product of ˜1:99, a selectivity unprecedented in both conventional, macroscopic reactors and other microfluidic systems. Additionally, the ability to separate different stages during the NP formation process inside the microreactor, allowed us to study the aggregation of polypyrrole NPs. II: Supramolecular actuators and molecular interlocked molecules, such as catenanes and rotaxanes, have attracted considerable attention because of their sophisticated topology and their application in functional molecular devices. The blending of supramolecular and mechanostereochemistry with mesoporous silica NPs has proven to be a powerful combination, leading to the development of a new class of materials -- mechanized silica nanoparticles ( Chapter 2). These new hybrid materials are designed to release their content in response to an external stimuli and their development is being driven by the need to improve current drug delivery technologies. In an effort to explore how the stimuli-controlled mechanical movement of switchable, bistable [2]rotaxanes -- based on a cyclobis(paraquat-p-phenylene) ring

  4. Microbial reverse-electrodialysis chemical-production cell for acid and alkali production

    KAUST Repository

    Zhu, Xiuping

    2013-06-01

    A new type of bioelectrochemical system, called a microbial reverse-electrodialysis chemical-production cell (MRCC), was developed to produce acid and alkali using energy derived from organic matter (acetate) and salinity gradients (NaCl solutions representative of seawater and river water). A bipolar membrane (BPM) was placed next to the anode to prevent Cl- contamination and acidification of the anolyte, and to produce protons for HCl recovery. A 5-cell paired reverse-electrodialysis (RED) stack provided the electrical energy required to overcome the BPM over-potential (0.3-0.6 V), making the overall process spontaneous. The MRCC reactor produced electricity (908 mW/m2) as well as concentrated acidic and alkaline solutions, and therefore did not require an external power supply. After a fed-batch cycle, the pHs of the chemical product solutions were 1.65 ± 0.04 and 11.98 ± 0.10, due to the production of 1.35 ± 0.13 mmol of acid, and 0.59 ± 0.14 mmol of alkali. The acid- and alkali-production efficiencies based on generated current were 58 ± 3% and 25 ± 3%. These results demonstrated proof-of-concept acid and alkali production using only renewable energy sources. © 2013 Elsevier B.V.

  5. Chemically transferable coarse-grained potentials from conditional reversible work calculations.

    Science.gov (United States)

    Brini, E; van der Vegt, N F A

    2012-10-21

    The representability and transferability of effective pair potentials used in multiscale simulations of soft matter systems is ill understood. In this paper, we study liquid state systems composed of n-alkanes, the coarse-grained (CG) potential of which may be assumed pairwise additive and has been obtained using the conditional reversible work (CRW) method. The CRW method is a free-energy-based coarse-graining procedure, which, by means of performing the coarse graining at pair level, rigorously provides a pair potential that describes the interaction free energy between two mapped atom groups (beads) embedded in their respective chemical environments. The pairwise nature of the interactions combined with their dependence on the chemically bonded environment makes CRW potentials ideally suited in studies of chemical transferability. We report CRW potentials for hexane using a mapping scheme that merges two heavy atoms in one CG bead. It is shown that the model is chemically and thermodynamically transferable to alkanes of different chain lengths in the liquid phase at temperatures between the melting and the boiling point under atmospheric (1 atm) pressure conditions. It is further shown that CRW-CG potentials may be readily obtained from a single simulation of the liquid state using the free energy perturbation method, thereby providing a fast and versatile molecular coarse graining method for aliphatic molecules. PMID:23083154

  6. An automated microreactor for semi-continuous biosensor measurements.

    Science.gov (United States)

    Buffi, Nina; Beggah, Siham; Truffer, Frederic; Geiser, Martial; van Lintel, Harald; Renaud, Philippe; van der Meer, Jan Roelof

    2016-04-21

    Living bacteria or yeast cells are frequently used as bioreporters for the detection of specific chemical analytes or conditions of sample toxicity. In particular, bacteria or yeast equipped with synthetic gene circuitry that allows the production of a reliable non-cognate signal (e.g., fluorescent protein or bioluminescence) in response to a defined target make robust and flexible analytical platforms. We report here how bacterial cells expressing a fluorescence reporter ("bactosensors"), which are mostly used for batch sample analysis, can be deployed for automated semi-continuous target analysis in a single concise biochip. Escherichia coli-based bactosensor cells were continuously grown in a 13 or 50 nanoliter-volume reactor on a two-layered polydimethylsiloxane-on-glass microfluidic chip. Physiologically active cells were directed from the nl-reactor to a dedicated sample exposure area, where they were concentrated and reacted in 40 minutes with the target chemical by localized emission of the fluorescent reporter signal. We demonstrate the functioning of the bactosensor-chip by the automated detection of 50 μgarsenite-As l(-1) in water on consecutive days and after a one-week constant operation. Best induction of the bactosensors of 6-9-fold to 50 μg l(-1) was found at an apparent dilution rate of 0.12 h(-1) in the 50 nl microreactor. The bactosensor chip principle could be widely applicable to construct automated monitoring devices for a variety of targets in different environments. PMID:27001545

  7. Shape and topology optimization of enzymatic microreactors

    DEFF Research Database (Denmark)

    Pereira Rosinha, Ines

    structure and results in the deformation of the configuration. Topologyoptimization contributes to the improvement of the layout of the material in a domain. Themechanical performance of a structure is evaluated by an objective function which can be for example maximizing its stiffness.The need for...... of extensive experimental work to find the best reactor configuration.Shape optimization has been applied to an YY-microreactor with a rectangular cross-section withthe intention to investigate the shape influence on the active mixing of substances and consequently in the reaction yield. The inlet...... such as height and width. This is achieved by a computational fluid dynamic (CFD) simulation study, which investigates a biocatalyticreaction for the production of optically pure chiral amines in the reactor system. The routine implements kinetic models into a CFD framework (ANSYS CFX®), which is...

  8. Heterogeneous catalysis in highly sensitive microreactors

    DEFF Research Database (Denmark)

    Olsen, Jakob Lind

    oxygen surplus, is presented. The e_ect of pretreating the catalyst, CuZnO, in a mixture of H2 and CO before methanol synthesis, is presented. Transient increased methanol production is seen after pretreatment, with a maximum in the transient for a pretreatment with a one to one CO to H2 ratio. The...... highly active state of the catalyst after pretreatment in a CO and H2 mixture is shown to have transient methanol synthesis capabilities at 60.. Estimates of the area of the catalytic surface, is obtained using formate temperature programmed desorption measurements. From these, the possibility of...... adsorbates readily converted to methanol as the source of the transient increase in methanol production, is eliminated. A study of mass selected ruthenium nanoparticles from a magnetron-sputter gas-aggregation source, deposited in microreactors, is presented. It is, shown that CO methanation can be measured...

  9. Bacteriophage adsorption during transport through porous media: Chemical perturbations and reversibility

    Science.gov (United States)

    Bales, R.C.; Hinkle, S.R.; Kroeger, T.W.; Stocking, K.; Gerba, C.P.

    1991-01-01

    In a series of seven column experiments, attachment of the bacteriophage PRD-1 and MS-2 to silica beads at pH's 5.0-5.5 was at least partially reversible; however, release of attached phage was slow and breakthrough curves exhibited significant tailing. Rate coefficients for attachment and detachment were on the order of 10-4 and 10-6-10-4 s-1, respectively. Corresponding time scales were hours for attachment and days for detachment. The sticking efficiency (??) for phage attachment was near 0.01. The rate of phage release was enhanced by raising pH and introducing surface-active chemical species, illustrating the importance of chemical perturbations in promoting biocolloid transport. In a series of batch experiments, MS-2 adsorbed strongly to a hydrophobic surface, octadecyltrichlorosilane-bonded silica, at both pH's 5 and 7. Adsorption to the unbonded silica at pH 5 was linear, but was 2.5 (with Ca2+) to 0.25% (without Ca2+) of that to the bonded surface. Neither MS-2 nor PRD-1 adsorbed to unbonded silica at pH 7. Hydrophobic effects appear to be important for adsorption of even relatively hydrophilic biocolloids. ?? 1991 American Chemical Society.

  10. Microreactors and CFD as Tools for Biocatalysis Reactor Design: A case study

    DEFF Research Database (Denmark)

    Bodla, Vijaya Krishna; Seerup, R.; Krühne, Ulrich; Woodley, J. M.; Gernaey, Krist

    2013-01-01

    Microreactors have been used for acquiring process data while consuming significantly lower amounts of expensive reagents. In this article, the combination of microreactor technology and computational fluid dynamics (CFD) is shown to contribute significantly towards understanding the diffusional ...

  11. Method for sample preparation for cryoelectron microscopy (CEM) microreactor and loading platform

    OpenAIRE

    H.W. Zandbergen; Ahn, C. W.

    2008-01-01

    A method for sample preparation for cryoelectron microscopy (CEM), wherein the sample is held in a microreactor, wherein the conditions in the microreactor are regulated relative to the environment, wherein the sample in the microreactor is frozen according to a quench freeze process, whereupon the sample, in frozen condition, is placed in the electron microscope. A microreactor for use with cryoelectron microscopy (CEM), comprising a first and second membrane, which membranes, at least in a ...

  12. Microreactors as tools for synthetic chemists-the chemists' round-bottomed flask of the 21st century?

    Science.gov (United States)

    Geyer, Karolin; Codée, Jeroen D C; Seeberger, Peter H

    2006-11-15

    Will microreactors replace the round-bottomed flask to perform chemical reactions in the near future? Recent developments in the construction of microstructured reaction devices and their wide-ranging applications in many different areas of chemistry suggest that they can have a significant impact on the way chemists conduct their experiments. Miniaturizing reactions offers many advantages for the synthetic organic chemist: high-throughput scanning of reaction conditions, precise control of reaction variables, the use of small quantities of reagents, increased safety parameters, and ready scale-up of synthetic procedures. A wide range of single- and multiphase reactions have now been performed in microfluidic-based devices. Certainly, microreactors cannot be applied to all chemistries yet and microfluidic systems also have disadvantages. Limited reaction-time range, high sensitivity to precipitating products, and new physical, chemical, and analytical challenges have to be overcome. This concept article presents an overview of microfluidic devices available for chemical synthesis and evaluates the potential of microreactor technology in organic synthesis. PMID:16991184

  13. Method for sample preparation for cryoelectron microscopy (CEM) microreactor and loading platform

    NARCIS (Netherlands)

    Zandbergen, H.W.; Ahn, C.W.

    2008-01-01

    A method for sample preparation for cryoelectron microscopy (CEM), wherein the sample is held in a microreactor, wherein the conditions in the microreactor are regulated relative to the environment, wherein the sample in the microreactor is frozen according to a quench freeze process, whereupon the

  14. Autonomous colloidal crystallization in a galvanic microreactor

    Science.gov (United States)

    Punckt, Christian; Jan, Linda; Jiang, Peng; Frewen, Thomas A.; Saville, Dudley A.; Kevrekidis, Ioannis G.; Aksay, Ilhan A.

    2012-10-01

    We report on a technique that utilizes an array of galvanic microreactors to guide the assembly of two-dimensional colloidal crystals with spatial and orientational order. Our system is comprised of an array of copper and gold electrodes in a coplanar arrangement, immersed in a dilute hydrochloric acid solution in which colloidal micro-spheres of polystyrene and silica are suspended. Under optimized conditions, two-dimensional colloidal crystals form at the anodic copper with patterns and crystal orientation governed by the electrode geometry. After the aggregation process, the colloidal particles are cemented to the substrate by co-deposition of reaction products. As we vary the electrode geometry, the dissolution rate of the copper electrodes is altered. This way, we control the colloidal motion as well as the degree of reaction product formation. We show that particle motion is governed by a combination of electrokinetic effects acting directly on the colloidal particles and bulk electrolyte flow generated at the copper-gold interface.

  15. Effect of conventional chemical treatment on the microbial population in a biofouling layer of reverse osmosis systems

    NARCIS (Netherlands)

    Bereschenko, L.A.; Prummel, H.; Euverink, G.J.W.; Stams, A.J.M.; Loosdrecht, van M.C.M.

    2011-01-01

    The impact of conventional chemical treatment on initiation and spatiotemporal development of biofilms on reverse osmosis (RO) membranes was investigated in situ using flow cells placed in parallel with the RO system of a full-scale water treatment plant. The flow cells got the same feed (extensivel

  16. Novel monolithic enzymatic microreactor based on single-enzyme nanoparticles for highly efficient proteolysis and its application in multidimensional liquid chromatography.

    Science.gov (United States)

    Gao, Mingxia; Zhang, Peng; Hong, Guangfeng; Guan, Xia; Yan, Guoquan; Deng, Chunhui; Zhang, Xiangmin

    2009-10-30

    In this work, a novel and facile monolithic enzymatic microreactor was prepared in the fused-silica capillary via a two-step procedure including surface acryloylation and in situ aqueous polymerization/immobilization to encapsulate a single enzyme, and its application to fast protein digestion through a direct matrix-assisted laser desorption/ionization time-of-flight mass spectrometer (MALDI-TOF-MS) analysis was demonstrated. At first, vinyl groups on the protein surface were generated by a mild acryloylation with N-acryloxysuccinimide in alkali buffer. Then, acryloylated enzyme was encapsulated into polyacrylates by free-radical copolymerization with acrylamide as the monomer, N,N'-methylenebisacrylamide as the cross-linker, and N,N,N',N'-tetramethylethylenediamine/ammonium persulfate as the initiator. Finally, polymers were immobilized onto the activated inner wall of capillaries via the reaction of vinyl groups. Capability of the enzyme-immobilized monolithic microreactor was demonstrated by myoglobin and bovine serum albumin as model proteins. The digestion products were characterized using MALDI-TOF-MS with sequence coverage of 94% and 29% observed. This microreactor was also applied to the analysis of fractions through two-dimensional separation of weak anion exchange/reversed-phase liquid chromatography of human liver extract. After a database search, 16 unique peptides corresponding to 3 proteins were identified when two RPLC fractions of human liver extract were digested by the microreactor. This opens a route for its future application in top-down proteomic analysis. PMID:19481218

  17. Performance and cost of energy transport and storage systems for dish applications using reversible chemical reactions

    Science.gov (United States)

    Schredder, J. M.; Fujita, T.

    1984-01-01

    The use of reversible chemical reactions for energy transport and storage for parabolic dish networks is considered. Performance and cost characteristics are estimated for systems using three reactions (sulfur-trioxide decomposition, steam reforming of methane, and carbon-dioxide reforming of methane). Systems are considered with and without storage, and in several energy-delivery configurations that give different profiles of energy delivered versus temperature. Cost estimates are derived assuming the use of metal components and of advanced ceramics. (The latter reduces the costs by three- to five-fold). The process that led to the selection of the three reactions is described, and the effects of varying temperatures, pressures, and heat exchanger sizes are addressed. A state-of-the-art survey was performed as part of this study. As a result of this survey, it appears that formidable technical risks exist for any attempt to implement the systems analyzed in this study, especially in the area of reactor design and performance. The behavior of all components and complete systems under thermal energy transients is very poorly understood. This study indicates that thermochemical storage systems that store reactants as liquids have efficiencies below 60%, which is in agreement with the findings of earlier investigators.

  18. Post-Digestion Liquor Treatment in the Method Combining Chemical Precipitation with Reverse Osmosis

    Directory of Open Access Journals (Sweden)

    Kuglarz Mariusz

    2014-12-01

    Full Text Available The aim of the study was to develop an effective treatment of post-digestion liquors highly-loaded with biogenic and organic substances. The scope of the research project encompassed: mesophilic anaerobic digestion of waste activated sludge (WAS as well as the treatment of post-digestion liquors, coming from the most appropriate HRT value of 25 days, in the process of ammonium magnesium phosphate (struvite precipitation targeted at ammonia nitrogen binding and a subsequent reverse osmosis (RO process. It was established that the method combining chemical precipitation and high-pressure filtration ensures a high degree of contaminants removal allowing for a direct release of treated liquors into the natural reservoir. However, in order to decrease the residual NH4+ concentration (6.1 mg NH4+/dm3 in the purified post-digestion liquors below the level allowing for a direct release to the natural reservoir, it turned out to be necessary to apply increased molar ratio of magnesium and phosphates (Mg:NH4+: PO43-= 1.5:1:1.5.

  19. Reversible solid oxide fuel cells (R-SOFCs) with chemically stable proton-conducting oxides

    KAUST Repository

    Bi, Lei

    2015-07-01

    Proton-conducting oxides offer a promising way of lowering the working temperature of solid oxide cells to the intermediate temperate range (500 to 700. °C) due to their better ionic conductivity. In addition, the application of proton-conducting oxides in both solid oxide fuel cells (SOFCs) and sold oxide electrolysis cells (SOECs) provides unique advantages compared with the use of conventional oxygen-ion conducting conductors, including the formation of water at the air electrode site. Since the discovery of proton conduction in some oxides about 30. years ago, the development of proton-conducting oxides in SOFCs and SOECs (the reverse mode of SOFCs) has gained increased attention. This paper briefly summarizes the development in the recent years of R-SOFCs with proton-conducting electrolytes, focusing on discussing the importance of adopting chemically stable materials in both fuel cell and electrolysis modes. The development of electrode materials for proton-conducting R-SOFCs is also discussed. © 2015 Elsevier B.V.

  20. Theoretical description of spin-selective reactions of radical pairs diffusing in spherical 2D and 3D microreactors

    Energy Technology Data Exchange (ETDEWEB)

    Ivanov, Konstantin L., E-mail: ivanov@tomo.nsc.ru; Lukzen, Nikita N. [International Tomography Center, Siberian Branch, Russian Academy of Sciences, Institutskaya St. 3a, Novosibirsk 630090 (Russian Federation); Novosibirsk State University, Pirogova St. 2, Novosibirsk 630090 (Russian Federation); Sadovsky, Vladimir M. [Institute of Computational Modeling, Siberian Branch, Russian Academy of Sciences, Akademgorodok 50/44, Krasnoyarsk 660036 (Russian Federation)

    2015-08-28

    In this work, we treat spin-selective recombination of a geminate radical pair (RP) in a spherical “microreactor,” i.e., of a RP confined in a micelle, vesicle, or liposome. We consider the microreactor model proposed earlier, in which one of the radicals is located at the center of the micelle and the other one undergoes three-dimensional diffusion inside the micelle. In addition, we suggest a two-dimensional model, in which one of the radicals is located at the “pole” of the sphere, while the other one diffuses on the spherical surface. For this model, we have obtained a general analytical expression for the RP recombination yield in terms of the free Green function of two-dimensional diffusion motion. In turn, this Green function is expressed via the Legendre functions and thus takes account of diffusion over a restricted spherical surface and its curvature. The obtained expression allows one to calculate the RP recombination efficiency at an arbitrary magnetic field strength. We performed a comparison of the two models taking the same geometric parameters (i.e., the microreactor radius and the closest approach distance of the radicals), chemical reactivity, magnetic interactions in the RP and diffusion coefficient. Significant difference between the predictions of the two models is found, which is thus originating solely from the dimensionality effect: for different dimensionality of space, the statistics of diffusional contacts of radicals becomes different altering the reaction yield. We have calculated the magnetic field dependence of the RP reaction yield and chemically induced dynamic nuclear polarization of the reaction products at different sizes of the microreactor, exchange interaction, and spin relaxation rates. Interestingly, due to the intricate interplay of diffusional contacts of reactants and spin dynamics, the dependence of the reaction yield on the microreactor radius is non-monotonous. Our results are of importance for (i) interpreting

  1. Theoretical description of spin-selective reactions of radical pairs diffusing in spherical 2D and 3D microreactors

    Science.gov (United States)

    Ivanov, Konstantin L.; Sadovsky, Vladimir M.; Lukzen, Nikita N.

    2015-08-01

    In this work, we treat spin-selective recombination of a geminate radical pair (RP) in a spherical "microreactor," i.e., of a RP confined in a micelle, vesicle, or liposome. We consider the microreactor model proposed earlier, in which one of the radicals is located at the center of the micelle and the other one undergoes three-dimensional diffusion inside the micelle. In addition, we suggest a two-dimensional model, in which one of the radicals is located at the "pole" of the sphere, while the other one diffuses on the spherical surface. For this model, we have obtained a general analytical expression for the RP recombination yield in terms of the free Green function of two-dimensional diffusion motion. In turn, this Green function is expressed via the Legendre functions and thus takes account of diffusion over a restricted spherical surface and its curvature. The obtained expression allows one to calculate the RP recombination efficiency at an arbitrary magnetic field strength. We performed a comparison of the two models taking the same geometric parameters (i.e., the microreactor radius and the closest approach distance of the radicals), chemical reactivity, magnetic interactions in the RP and diffusion coefficient. Significant difference between the predictions of the two models is found, which is thus originating solely from the dimensionality effect: for different dimensionality of space, the statistics of diffusional contacts of radicals becomes different altering the reaction yield. We have calculated the magnetic field dependence of the RP reaction yield and chemically induced dynamic nuclear polarization of the reaction products at different sizes of the microreactor, exchange interaction, and spin relaxation rates. Interestingly, due to the intricate interplay of diffusional contacts of reactants and spin dynamics, the dependence of the reaction yield on the microreactor radius is non-monotonous. Our results are of importance for (i) interpreting

  2. Theoretical description of spin-selective reactions of radical pairs diffusing in spherical 2D and 3D microreactors

    International Nuclear Information System (INIS)

    In this work, we treat spin-selective recombination of a geminate radical pair (RP) in a spherical “microreactor,” i.e., of a RP confined in a micelle, vesicle, or liposome. We consider the microreactor model proposed earlier, in which one of the radicals is located at the center of the micelle and the other one undergoes three-dimensional diffusion inside the micelle. In addition, we suggest a two-dimensional model, in which one of the radicals is located at the “pole” of the sphere, while the other one diffuses on the spherical surface. For this model, we have obtained a general analytical expression for the RP recombination yield in terms of the free Green function of two-dimensional diffusion motion. In turn, this Green function is expressed via the Legendre functions and thus takes account of diffusion over a restricted spherical surface and its curvature. The obtained expression allows one to calculate the RP recombination efficiency at an arbitrary magnetic field strength. We performed a comparison of the two models taking the same geometric parameters (i.e., the microreactor radius and the closest approach distance of the radicals), chemical reactivity, magnetic interactions in the RP and diffusion coefficient. Significant difference between the predictions of the two models is found, which is thus originating solely from the dimensionality effect: for different dimensionality of space, the statistics of diffusional contacts of radicals becomes different altering the reaction yield. We have calculated the magnetic field dependence of the RP reaction yield and chemically induced dynamic nuclear polarization of the reaction products at different sizes of the microreactor, exchange interaction, and spin relaxation rates. Interestingly, due to the intricate interplay of diffusional contacts of reactants and spin dynamics, the dependence of the reaction yield on the microreactor radius is non-monotonous. Our results are of importance for (i) interpreting

  3. Hydrodynamics of multi-phase packed bed micro-reactors

    NARCIS (Netherlands)

    Márquez Luzardo, N.M.

    2010-01-01

    Why to use packed bed micro-reactors for catalyst testing? Miniaturized packed bed reactors have a large surface-to-volume ratio at the reactor and particle level that favors the heat- and mass-transfer processes at all scales (intra-particle, inter-phase and inter-particle or reactor level). If the

  4. Investigations of mass transfer in annular gas-liquid flow in a microreactor

    Directory of Open Access Journals (Sweden)

    Sobieszuk Paweł

    2016-03-01

    Full Text Available The paper presents an investigation of mass transfer in gas-liquid annular flow in a microreactor. The microreactor had a meandered shape with a square cross-section of the channel (292×292 μm, hydraulic diameter 292 μm and 250 mm in length. The rate of CO2 absorption from the CO2/N2 mixture in NaOH (0.1 M, 0.2 M, 0.7 M, 1.0 M and 1.5 M water solutions was measured. Two velocities of gas flow and two velocities of liquid flow were used. In two cases a fully developed annular flow at the beginning of the channel was observed, whilst in two cases annular flow was formed only in about 2/3 of the microchannel length. Based on the measurements of CO2 absorption rate, the values of volumetric liquid - side mass transfer coefficients with the chemical reaction were determined. Then physical values of coefficients were found. Obtained results were discussed and their values were compared with the values predicted by literature correlations.

  5. Synthetically chemical-electrical mechanism for controlling large scale reversible deformation of liquid metal objects

    OpenAIRE

    Zhang, Jie; Sheng, Lei; Liu, Jing

    2014-01-01

    Reversible deformation of a machine holds enormous promise across many scientific areas ranging from mechanical engineering to applied physics. So far, such capabilities are still hard to achieve through conventional rigid materials or depending mainly on elastomeric materials, which however own rather limited performances and require complicated manipulations. Here, we show a basic strategy which is fundamentally different from the existing ones to realize large scale reversible deformation ...

  6. Fouling of Seawater Reverse Osmosis (SWRO) Membrane: Chemical and Microbiological Characterization

    KAUST Repository

    Khan, Muhammad T.

    2013-12-01

    In spite of abundant water resources, world is suffering from the scarcity of usable water. Seawater Reverse Osmosis (SWRO) desalination technology using polymeric membranes has been recognized as a key solution to water scarcity problem. However, economic sustainability of this advanced technology is adversely impacted by the membrane fouling problem. Fouling of RO membranes is a highly studied phenomenon. However, literature is found to be lacking a detailed study on kinetic and dynamic aspects of SWRO membrane fouling. The factors that impact the fouling dynamics, i.e., pretreatment and water quality were also not adequately studied at full–scale of operation. Our experimental protocol was designed to systematically explore these fouling aspects with the objective to improve the understanding of SWRO membrane fouling mechanisms. An approach with multiple analytical techniques was developed for fouling characterization. In addition to the fouling layer characterization, feed water quality was also analysed to assess its fouling potential. Study of SWRO membrane fouling dynamics and kinetics revealed variations in relative abundance of chemical and microbial constituents of the fouling layer, over operating time. Aromatic substances, most likely humic–like substances, were observed at relatively high abundance in the initial fouling layer, followed by progressive increase in relative abundances of proteins and polysaccharides. Microbial population grown on all membranes was dominated by specific groups/species belonging to different classes of Proteobacteria phylum; however, similar to abiotic foulant, their relative abundance also changed with the biofilm age and with the position of membrane element in RO vessel. Our results demonstrated that source water quality can significantly impact the RO membrane fouling scenarios. Moreover, the major role of chlorination in the SWRO membrane fouling was highlighted. It was found that intermittent mode of chlorination

  7. "Snap-shooting" the interface of AOT reverse micelles: use of chemical trapping

    Science.gov (United States)

    Srilakshmi; Chaudhuri

    2000-08-01

    The first use of the phenyl cation trapping technique in "snap-shooting" the local molar concentrations of water and sulfosuccinate head-groups in the interfacial region of AOT-2,2,4-trimethylpentane-water reverse micelles has been accomplished. Our results demonstrate that the interfacial concentrations of the sulfosuccinate head-groups in AOT (0.1 M)-2,2,4-trimethylpentane-water reverse micelles are remarkably high (2.75-2.34 M) across the W0 (the molar ratio of water to surfactant) range 12 to 44. However, the interfacial concentrations of water in AOT- 2,2,4-trimethylpentane-water reverse micelles across the same range of solution compositions are significantly lower (27.9-32.0 M) than the molar concentration of bulk water (55.5 M). The present results provide new insight on the microenvironments of interfacially located enzymes such as lipases entrapped in AOT-2,2,4-trimethylpentane-water reverse micelles, the most extensively exploited reverse-micellar system in micellar biotechnology. PMID:10985732

  8. Chemical alloying induced collapse of reversibility windows in ternary As-S-I glasses*

    Science.gov (United States)

    Wang, Fei; Boolchand, P.

    2006-03-01

    Thermally reversing windows represent glass compositions across which glass transitions are thermally reversing in character. These windows have been observed in several chalcogenide glasses, and are identified^1 with self-organized phases of glassy networks. Upon alloying halogen (iodine) in base chalcogenide glasses (Ge-Se, Ge-S), the reversibility windows collapse^2 about the mean-field rigidity transition. We attempt to understand this behavior better. We have now synthesized ternary glass compositions of the type, (AsI3)x(As0.30S0.70)1-x and (AsI3)y (As2S3)1-y over wide composition ranges of x and y, and have examined them systematically in Raman scattering and MDSC experiments. Along with earlier results^3 on binary AszS1-z glasses, the present results permit mapping the reversibility window over the glass forming range of the present As-S-I ternary. The results show the window region to be of nearly triangular shape, with a base extending in the 0.20 85,3823 (2005). 2. Y. Wang et al. Phys. Rev. Lett. 87, 18, 5503 (2001) 3. D.G. Georgiev, Ph.D. Thesis , Univ. of Cincinnati (2003) unpublished

  9. Computational modelling of slug flow in a capillary microreactor

    Science.gov (United States)

    Kashid, M. N.; Platte, F.; Agar, D. W.; Turek, S.

    2007-06-01

    The benefits of slug flow capillary microreactor exhibit the ability to adjust two individual transport mechanisms, i.e., convection inside the slug and diffusion between two consecutive slugs. The mass transfer rate is enhanced by internal circulation, which arises due to the shear between slug axis and continuous phase or capillary wall. The knowledge of circulation patterns within the slug plays an important role in the design of a capillary microreactor. Apart from this, well defined slug flow generation is a key activity in the development of methodology to study hydrodynamics and mass transfer. In the present paper we discuss computational fluid dynamics (CFD) modelling aspects of internal circulations (single phase) and slug flow generation (two-phase).

  10. (Invited) Microreactors for Characterization and Benchmarking of Photocatalysts

    DEFF Research Database (Denmark)

    Vesborg, Peter Christian Kjærgaard; Dionigi, Fabio; Trimarco, Daniel Bøndergaard;

    2015-01-01

    In the field of photocatalysis the batch-nature of the typical benchmarking experiment makes it very laborious to obtain good kinetic data as a function of parameters such as illumination wavelength, irradiance, catalyst temperature, reactant composition, etc. Microreactors with on-line mass spec......] Dionigi et al. Rev. Sci. Instr., 84, p. 103910 (2013) [6] Bøndergaard et al. "Fast and sensitive method for detecting volatile species in liquids", submitted...

  11. Rapid Wolff–Kishner reductions in a silicon carbide microreactor

    OpenAIRE

    Newman, Stephen G.; Gu, Lei; Lesniak, Christoph; Victor, Georg; Meschke, Frank; Abahmane, Lahbib; Jensen, Klavs F.

    2013-01-01

    Wolff–Kishner reductions are performed in a novel silicon carbide microreactor. Greatly reduced reaction times and safer operation are achieved, giving high yields without requiring a large excess of hydrazine. The corrosion resistance of silicon carbide avoids the problematic reactor compatibility issues that arise when Wolff–Kishner reductions are done in glass or stainless steel reactors. With only nitrogen gas and water as by-products, this opens the possibility of performing selective, l...

  12. Fabrication of a microreactor by proton beam writing technique

    International Nuclear Information System (INIS)

    Microreactors are innovative and promising tools in technology nowadays because of their advantages compared to the conventional-scale reactors. These advantages include vast improvements in surface to volume ratio, energy efficiency, reaction speed and yield and increased control of reaction conditions, to name a few examples. The high resolution capability of the micromachining technique utilizing accelerated ion beams in the fabrication technology of microreactors has not yet been taken advantage of. In this work we present the design of a prototype micro-electrochemical cell of 1.5 μL volume (2.5 x 2.5 x 0.240 mm) created with a 3 MeV proton microbeam. The cell can be separated into two half-cells with a suitable membrane applicable to galvanic or fuel cells as well. We deposited gold electrodes on both of the half-cells. The operability of the device was demonstrated by electric current flow between the two electrodes in this micro-electrochemical cell containing a simple electrolyte solution. We used a polycapillary film to separate the two half-cells, hindering the mixing of the anolyte and catholyte solutions. As a result of the minimal mixing caused by the polycapillary film, this cell design can be suitable for electro-synthesis. Due to the high resolution of proton beam writing, it is planned to reduce the dimensions of this kind of microreactor.

  13. Fabrication of a microreactor by proton beam writing technique

    Science.gov (United States)

    Huszank, R.; Szilasi, S. Z.; Vad, K.; Rajta, I.

    2009-06-01

    Microreactors are innovative and promising tools in technology nowadays because of their advantages compared to the conventional-scale reactors. These advantages include vast improvements in surface to volume ratio, energy efficiency, reaction speed and yield and increased control of reaction conditions, to name a few examples. The high resolution capability of the micromachining technique utilizing accelerated ion beams in the fabrication technology of microreactors has not yet been taken advantage of. In this work we present the design of a prototype micro-electrochemical cell of 1.5 μL volume (2.5 × 2.5 × 0.240 mm) created with a 3 MeV proton microbeam. The cell can be separated into two half-cells with a suitable membrane applicable to galvanic or fuel cells as well. We deposited gold electrodes on both of the half-cells. The operability of the device was demonstrated by electric current flow between the two electrodes in this micro-electrochemical cell containing a simple electrolyte solution. We used a polycapillary film to separate the two half-cells, hindering the mixing of the anolyte and catholyte solutions. As a result of the minimal mixing caused by the polycapillary film, this cell design can be suitable for electro-synthesis. Due to the high resolution of proton beam writing, it is planned to reduce the dimensions of this kind of microreactor.

  14. Triple-channel microreactor for biphasic gas–liquid reactions: Photosensitized oxygenations

    Directory of Open Access Journals (Sweden)

    Ram Awatar Maurya

    2011-08-01

    Full Text Available A triple-channel microreactor fabricated by means of a soft-lithography technique was devised for efficient biphasic gas–liquid reactions. The excellent performance of the microreactor was demonstrated by carrying out photosensitized oxygenations of α-terpinene, citronellol, and allyl alcohols.

  15. A new pulsed electric field microreactor: comparison between the laboratory and microtechnology scale

    NARCIS (Netherlands)

    Fox, Martijn; Esveld, Erik; Luttge, Regina; Boom, Remko

    2005-01-01

    This paper presents a new microreactor dedicated for pulsed electric field treatment (PEF), which is a pasteurization method that inactivates microorganisms with short electric pulses. The PEF microreactor consists of a flow-through channel with a constriction where the electric field is focussed. C

  16. A convenient enantioselective CBS-reduction of arylketones in flow-microreactor systems.

    Science.gov (United States)

    De Angelis, Sonia; De Renzo, Maddalena; Carlucci, Claudia; Degennaro, Leonardo; Luisi, Renzo

    2016-05-01

    A convenient, versatile, and green CBS-asymmetric reduction of aryl and heteroaryl ketones has been developed by using the microreactor technology. The study demonstrates that it is possible to handle borane solution safely within microreactors and that the reaction performs well using 2-MeTHF as a greener solvent. PMID:27086654

  17. Triple-channel microreactor for biphasic gas–liquid reactions: Photosensitized oxygenations

    OpenAIRE

    Ram Awatar Maurya; Chan Pil Park; Dong-Pyo Kim

    2011-01-01

    A triple-channel microreactor fabricated by means of a soft-lithography technique was devised for efficient biphasic gas–liquid reactions. The excellent performance of the microreactor was demonstrated by carrying out photosensitized oxygenations of α-terpinene, citronellol, and allyl alcohols.

  18. On the hydrodynamics of liquid–liquid slug flow capillary microreactors

    NARCIS (Netherlands)

    Kashid, M.N.; Fernandez Rivas, D.; Agar, D.W.; Turek, S.

    2008-01-01

    Microreactor technology is an important method of process intensification. Liquid–liquid slug flow capillary microreactors have been used to intensify the reactions with heat and mass transfer limitations. In this type of reactor, either two liquids flow alternate to each other in a capillary or one

  19. The use of microbial and chemical analyses to characterize the variations in fouling profile of seawater reverse osmosis (SWRO) membrane

    KAUST Repository

    Manes, Carmem Lara De O

    2013-01-01

    Biofouling of reverse osmosis (RO) membranes is one of the most common problems in desalinations plants reducing the efficiency of the water production process. The characterization of bacterial community composition from fouling layers as well as detailed analysis of surrounding chemical environment might reveal process specific bacterial groups/species that are involved in RO biofouling. In this study, advanced organics analytic methods (elemental analysis, FTIR, and ICP-OES) were combined with high-throughput 16S rRNA (pyro) sequencing to assess in parallel, the chemical properties and the active microbial community composition of SWRO membranes from a pilot desalination plant (MFT, Tarragona) in February 2011 and July 2011. Prefiltered ultrafiltration. waters fed SWRO membranes during third and fifth month of operation, respectively. SWRO samples were taken from three modules at different positions (first, fourth, and sixth) in order to investigate the spatial changes in fouling layers\\' chemical and microbiological composition. The overall assessment of chemical parameters revealed that fouling layers were mainly composed by bio and organic material (proteins and lipids). Ca and Fe were found to be the most abundant elements having an increasing concentration gradient according to the module position. Bacterial community composition of SWRO membranes is mostly represented by the Gammaproteobacteria class with interesting differences in genera/species spatial and temporal distribution. This preliminary result suggests that pretreatments and/or operational conditions might have selected different bacterial groups more adapted to colonize SWRO membranes. © 2013 Desalination Publications.

  20. Combination of Maldi-tof mass spectrometry with immobilized enzyme microreactor for peptide mapping

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) has been combined with immobilized enzyme microreactor for the rapid, sensitive, and accurate tryptic mapping of protein and polypeptides. The technique utilizes the trypsin microreactor by immobilized enzyme on the glycidyl methacrylate (GMA)-modified cellulose membrane. The membrane microreactor was used for the tryptic mapping of cytochrome C and the results were compared with those obtained by using free trypsin. A significant increase in the overall sensitivity of the process was observed using the membrane microreactor, as well as the elimination of background signals due to the autolysis of the trypsin. Further, membrane microreactor digestions were found to be rapid and convenient.

  1. Combination of MALDI-TOF mass spectrometry with immobilized enzyme microreactor for peptide mapping

    Institute of Scientific and Technical Information of China (English)

    姜泓海; 邹汉法; 汪海林; 张强; 倪坚毅; 张清春; 郭忠; 陈小明

    2000-01-01

    Matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) has been combined with immobilized enzyme microreactor for the rapid, sensitive, and accurate tryptic mapping of protein and polypeptides. The technique utilizes the trypsin microreactor by immobilized enzyme on the glycidyl methacrylate (GMA)-modified cellulose membrane. The membrane micro-reactor was used for the tryptic mapping of cytochrome C and the results were compared with those obtained by using free trypsin. A significant increase in the overall sensitivity of the process was observed using the membrane microreactor, as well as the elimination of background signals due to the autolysis of the trypsin. Further, membrane microreactor digestions were found to be rapid and convenient.

  2. Do High School Chemistry Examinations Inhibit Deeper Level Understanding of Dynamic Reversible Chemical Reactions?

    Science.gov (United States)

    Wheeldon, R.; Atkinson, R.; Dawes, A.; Levinson, R.

    2012-01-01

    Background and purpose: Chemistry examinations can favour the deployment of algorithmic procedures like Le Chatelier's Principle (LCP) rather than reasoning using chemical principles. This study investigated the explanatory resources which high school students use to answer equilibrium problems and whether the marks given for examination answers…

  3. Practical Engineering Aspects of Catalysis in Microreactors

    Czech Academy of Sciences Publication Activity Database

    Křišťál, Jiří; Stavárek, Petr; Vajglová, Zuzana; Vondráčková, Magdalena; Pavlorková, Jana; Jiřičný, Vladimír

    2015-01-01

    Roč. 41, č. 12 (2015), s. 9357-9371. ISSN 0922-6168. [Pannonian Symposium on Catalysis /12./. Castle Trest, 16.09.2014-20.09.2014] Institutional support: RVO:67985858 Keywords : heterogeneous catalysis * homogeneous catalysis * photo catalysis Subject RIV: CI - Industrial Chemistry, Chemical Engineering Impact factor: 1.221, year: 2014

  4. Reverse Pulse Voltammetry at Spherical and Disc Microelectrodes: Characterization of Homogeneous Chemical Equilibria and Their Impact on the Species Diffusivities

    International Nuclear Information System (INIS)

    The value of the electrochemical technique Reverse Pulse Voltammetry (RPV) for the characterization of chemical equilibria in solution is theoretically investigated. For this, the RPV response of the square scheme is studied at spherical and disc electrodes of any size assuming that the chemical reactions are at equilibrium. When the effective diffusion coefficients of the oxidized and reduced species are the same, analytical solutions are reported for both electrode geometries. Otherwise, a rigorous analytical solution is derived for spherical electrodes whereas the case of microdiscs is addressed by numerical simulations. The theory for the square scheme enables the study of the RPV response in very different situations, including the cases where the electrochemical and/or chemical transformations alter significantly the species diffusivity such as in electron transfer processes in room temperature ionic liquids or in the association of the electroactive species with (bio) macromolecules and nanoparticles. It is found that, when medium-size (disc or spherical) microelectrodes are employed, the RPV method enables the simultaneous determination of the effective diffusion coefficients of the oxidized and reduced species as well as the apparent formal potential. These magnitudes make it possible a sound physicochemical characterization of the system

  5. Hydrodynamics of multi-phase packed bed micro-reactors

    OpenAIRE

    Márquez Luzardo, N.M.

    2010-01-01

    Why to use packed bed micro-reactors for catalyst testing? Miniaturized packed bed reactors have a large surface-to-volume ratio at the reactor and particle level that favors the heat- and mass-transfer processes at all scales (intra-particle, inter-phase and inter-particle or reactor level). If the mass-transfer processes are fast in respect to the reaction-rate, then the reaction-rate is under kinetic control over the entire range of conversion and it is possible to measure intrinsic kineti...

  6. Design of micro-reactors and solar photocatalytic prototypes

    International Nuclear Information System (INIS)

    In the ININ is carried out research in heterogeneous photocatalysis using artificial light for to degrade organic compounds. In this context, it is sought to use the solar radiation as energy source to knock down costs. Of equal form it requires to link the basic and applied research. For it, a methodology that allows to design and to build micro-reactors and plants pilot has been developed, like previous step, to request external supports and to a future commercialization. The beginning of these works gave place to the partial construction of a prototype of photocatalytic reactor of the cylinder-parabolic composed type (CPC)

  7. Surface modification of reverse osmosis desalination membranes by thin-film coatings deposited by initiated chemical vapor deposition

    Energy Technology Data Exchange (ETDEWEB)

    Ozaydin-Ince, Gozde, E-mail: gozdeince@sabanciuniv.edu [Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States); Matin, Asif, E-mail: amatin@mit.edu [Department of Mechanical Engineering, King Fahd University of Petroleum and Minerals, Dhahran 31261 (Saudi Arabia); Khan, Zafarullah, E-mail: zukhan@mit.edu [Department of Mechanical Engineering, King Fahd University of Petroleum and Minerals, Dhahran 31261 (Saudi Arabia); Zaidi, S.M. Javaid, E-mail: zaidismj@kfupm.edu.sa [Department of Mechanical Engineering, King Fahd University of Petroleum and Minerals, Dhahran 31261 (Saudi Arabia); Gleason, Karen K., E-mail: kkgleasn@mit.edu [Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States)

    2013-07-31

    Thin-film polymeric reverse osmosis membranes, due to their high permeation rates and good salt rejection capabilities, are widely used for seawater desalination. However, these membranes are prone to biofouling, which affects their performance and efficiency. In this work, we report a method to modify the membrane surface without damaging the active layer or significantly affecting the performance of the membrane. Amphiphilic copolymer films of hydrophilic hydroxyethylmethacrylate and hydrophobic perfluorodecylacrylate (PFA) were synthesized and deposited on commercial RO membranes using an initiated chemical vapor deposition technique which is a polymer deposition technique that involves free-radical polymerization initiated by gas-phase radicals. Relevant surface characteristics such as hydrophilicity and roughness could be systematically controlled by varying the polymer chemistry. Increasing the hydrophobic PFA content in the films leads to an increase in the surface roughness and hydrophobicity. Furthermore, the surface morphology studies performed using the atomic force microscopy show that as the thickness of the coating increases average surface roughness increases. Using this knowledge, the coating thickness and chemistry were optimized to achieve high permeate flux and to reduce cell attachment. Results of the static bacterial adhesion tests show that the attachment of bacterial cells is significantly reduced on the coated membranes. - Highlights: • Thin films are deposited on reverse osmosis membranes. • Amphiphilic thin films are resistant to protein attachment. • The permeation performance of the membranes is not affected by the coating. • The thin film coatings delayed the biofouling.

  8. Surface modification of reverse osmosis desalination membranes by thin-film coatings deposited by initiated chemical vapor deposition

    International Nuclear Information System (INIS)

    Thin-film polymeric reverse osmosis membranes, due to their high permeation rates and good salt rejection capabilities, are widely used for seawater desalination. However, these membranes are prone to biofouling, which affects their performance and efficiency. In this work, we report a method to modify the membrane surface without damaging the active layer or significantly affecting the performance of the membrane. Amphiphilic copolymer films of hydrophilic hydroxyethylmethacrylate and hydrophobic perfluorodecylacrylate (PFA) were synthesized and deposited on commercial RO membranes using an initiated chemical vapor deposition technique which is a polymer deposition technique that involves free-radical polymerization initiated by gas-phase radicals. Relevant surface characteristics such as hydrophilicity and roughness could be systematically controlled by varying the polymer chemistry. Increasing the hydrophobic PFA content in the films leads to an increase in the surface roughness and hydrophobicity. Furthermore, the surface morphology studies performed using the atomic force microscopy show that as the thickness of the coating increases average surface roughness increases. Using this knowledge, the coating thickness and chemistry were optimized to achieve high permeate flux and to reduce cell attachment. Results of the static bacterial adhesion tests show that the attachment of bacterial cells is significantly reduced on the coated membranes. - Highlights: • Thin films are deposited on reverse osmosis membranes. • Amphiphilic thin films are resistant to protein attachment. • The permeation performance of the membranes is not affected by the coating. • The thin film coatings delayed the biofouling

  9. Highly sensitive silicon microreactor for catalyst testing

    DEFF Research Database (Denmark)

    Henriksen, Toke Riishøj; Olsen, Jakob Lind; Vesborg, Peter Christian Kjærgaard;

    2009-01-01

    A novel microfabricated chemical reactor for highly sensitive measurements of catalytic activity and surface kinetics is presented. The reactor is fabricated in a silicon chip and is intended for gas-phase reactions at pressures ranging from 0.1 to 5.0 bar. A high sensitivity is obtained by...... catalysts which can only be obtained in small quantities. Such measurements are of significant fundamental interest but are challenging because of the low surface areas involved. The relationship between the reaction zone gas flow and the pressure in the reaction zone is investigated experimentally. A...

  10. Micro-reactor for heterogeneous catalysis. Applications: hydrogen storage in hydrocarbons and filter for gas sensor

    International Nuclear Information System (INIS)

    This manuscript presents the design and the use of silicon micro-structured reactor for heterogeneous catalysis and especially for the dehydrogenation of methyl-cyclohexane reaction. This reaction enables on one hand to store hydrogen and on the other hand to realize technological developments since it is endothermic and difficult to carry out. By consequence, a new micro-reactor obtained by DRIE was designed and capped with a Pyrex wafer. It bundles micro-heaters deposited by screen-printing and a high temperature metallic connection. It comprises either a catalyst coming from micro-technology, Pt film deposited by sputtering or a classic catalyst, platinum supported on alumina. For this last catalyst, the micro-reactor previously pre-oxidized is pretreated by oxygen plasma or liquid way so that the deposit to walls. The wash coat could be done in open micro-reactor by dip coating in the suspension or in closed micro-reactor under vacuum or by liquid circulation. After catalytic tests realised in a macro-reactor, the Pt/Al2O3 catalyst was chosen to be inserted in the micro-reactor. The catalytic tests realised in a micro-reactor coupled with a mass spectrometer let to show the presence of hydrogen. In parallel, the micro-reactor was used as filter to improve gas sensor selectivity. (author)

  11. Methanol steam reforming in microreactor with constructal tree-shaped network

    Science.gov (United States)

    Chen, Yongping; Zhang, Chengbin; Wu, Rui; Shi, Mingheng

    2011-08-01

    The construcal tree-shaped network is introduced into the design of a methanol steam microreactor in the context of optimization of the flow configuration. A three-dimensional model for methanol steam reaction in this designed microreactor is developed and numerically analyzed. The methanol conversion, CO concentration in the product and the total pressure drop of the gases in the microreactor with constructal tree-shaped network are evaluated and compared with those in the serpentine reactor. It is found that the reaction of methanol steam reforming is enhanced in the constructal tree-shaped microreactor, since the tree-shaped reactor configuration, which acts an optimizer for the reactant distribution, provides a reaction space with larger surface-to-volume ratio and the reduction of reactant velocities in the branches. Compared with the serpentine microreactor, the constructal reactor possesses a higher methanol conversion rate accompanied with a higher CO concentration. The conversion rate of the constructal microreactor is more than 10% over that of serpentine reactor. More particularly, the reduction of flow distance makes the constructal microreactor still possess almost the same pressure drop as the corresponding serpentine reactor, despite that the bifurcations induce extra local pressure loss, and the reduction of channel size in branches also causes pressure losses.

  12. Design of micro-reactors and solar photocatalytic prototypes; Diseno de micro-reactores y prototipos fotocataliticos solares

    Energy Technology Data Exchange (ETDEWEB)

    Flores E, R.M.; Hernandez H, M.; Perusquia del Cueto, M.R.; Bonifacio M, J.; Jimenez B, J.; Ortiz O, H.B.; Castaneda J, G.; Lugo H, M. [ININ, Km. 36.5 Carr. Mexico-Toluca, 52750 La Marquesa, Ocoyoacac (Mexico)]. e-mail: rmfe@nuclear.inin.mx

    2007-07-01

    In the ININ is carried out research in heterogeneous photocatalysis using artificial light for to degrade organic compounds. In this context, it is sought to use the solar radiation as energy source to knock down costs. Of equal form it requires to link the basic and applied research. For it, a methodology that allows to design and to build micro-reactors and plants pilot has been developed, like previous step, to request external supports and to a future commercialization. The beginning of these works gave place to the partial construction of a prototype of photocatalytic reactor of the cylinder-parabolic composed type (CPC)

  13. Microreactor for the Catalytic Partial Oxidation of Methane

    Institute of Scientific and Technical Information of China (English)

    Widodo Wahyu Puwanto; Yuswan Muharam

    2006-01-01

    Fixed-bed reactors for the partial oxidation of methane to produce synthetic gas still pose hotspot problems. An alternative reactor, which is known as the shell-and-tube-typed microreactor, has been developed to resolve these problems. The microreactor consists of a 1 cm outside-diameter, 0.8 cm insidediameter and 11 cm length tube, and a 1.8 cm inside-diameter shell. The tube is made of dense alumina and the shell is made of quartz. Two different methods dip and spray coating were performed to line the tube side with the LaNixOy catalyst. Combustion and reforming reactions take place simultaneously in this reactor. Methane is oxidized in the tube side to produce flue gases (CO2 and H2O) which flow counter-currently and react with the remaining methane in the shell side to yield synthesis gas. The methane conversion using the higher-loading catalyst spray-coated tube reaches 97% at 700 ℃, whereas that using the lower-loading catalyst dip-coated tube reaches only 7.78% because of poor adhesion between the catalyst film and the alumina support. The turnover frequencies (TOFs) using the catalyst spray-and 900 ℃ provides better performance than that at 1250 ℃ because sintering reduces the surface-area. The hydrogen to carbon monoxide ratio produced by the spray-coated catalyst is greater than the stoichiometric ratio, which is caused by carbon deposition through methane cracking or the Boudouard reaction.

  14. Microreactors-A Powerful Tool to Synthesize Peroxycarboxylic Esters.

    Science.gov (United States)

    Illg, Tobias; Knorr, Annett; Fritzsche, Lutz

    2015-01-01

    The synthesis of peroxycarboxylic esters, as one subgroup of organic peroxides, is characterized by a high thermal hazard potential regarding process safety. In case of failure in the production process, e.g., if the heat of reaction cannot be removed sufficiently fast, decomposition reactions can be triggered, and as a result, remarkable amounts of heat and gas can be released and can cause a high extent of damage. Multifarious technical and organizational measures are necessary to ensure the safe industrial production of peroxides. With the introduction of microreaction technology plenty of possibilities have been opened to carry out highly exothermic reactions in smaller volumes and with more efficient heat removal. In this paper we report the application of three different microstructured reactors, representing different mixing strategies, to synthesize two peroxymonocarboxylic esters, namely tert-butyl peroxypivalate and tert-butyl peroxy-2-ethylhexanoate. The following reactor types were considered: an orifice microreactor, a split and recombine microreactor and a capillary tube reactor in combination with ultrasonication. The efficiency of the two phase liquid/liquid reaction is expressed in comparison of conversion and selectivity. With microreaction technology a remarkable increase in space-time-yield, ranging from 12,500 kg·m(-3)·h(-1) to 414,000 kg·m(-3)·h(-1), is achieved. PMID:26703553

  15. Hybrid poly(dimethylsiloxane)-silicon microreactors used for molecular computing

    Science.gov (United States)

    van Noort, Danny; Wagler, Patrick; McCaskill, John S.

    2002-10-01

    The goal of this research is to improve the modular stability and programmability of DNA-based computers and is a second step towards optical programmable DNA computing. The main focus here is on hydrodynamic stability. Clockable microreactors can be connected in various ways to solve combinatorial optimization problems, such as maximum clique or 3-SAT. This work demonstrates by construction how one microreactor design can be programmed to solve any instance of maximum clique up to its given maximum size (N). It reports on an implementation of the architecture proposed previously (McCaskill J S 2001 Biosystems 59 125-38). This contrasts with conventional DNA computing where the individual sequence of biochemical operations depends on the specific problem. In this pilot study we are tackling a graph for the maximum clique problem with N ≤ 12, with a special emphasis on N = 6. Furthermore, the design of the DNA solution space will be presented, which is symbolized by a set of bit-strings (words).

  16. Plasma microreactor in supercritical xenon and its application to diamondoid synthesis

    Science.gov (United States)

    Oshima, F.; Stauss, S.; Ishii, C.; Pai, D. Z.; Terashima, K.

    2012-10-01

    The generation of plasmas in a microreactor is demonstrated in xenon from atmospheric pressure up to supercritical conditions. Ac high voltage at a frequency of 15 kHz was applied across a 25-µm discharge gap between a tungsten wire and a fused silica micro-capillary tube in a coaxial configuration. Using this continuous flow supercritical fluid microreactor, it was possible to synthesize diamantane and other diamondoids up to nonamantane, using adamantane as a precursor and seed. It is anticipated that plasmas generated in supercritical fluid microreactors may not only allow faster fabrication of diamondoids, but also offer opportunities for the fabrication of other nanomaterials.

  17. Droplet-based microreactor for synthesis of water-soluble Ag2S quantum dots

    Science.gov (United States)

    Shu, Yun; Jiang, Peng; Pang, Dai-Wen; Zhang, Zhi-Ling

    2015-07-01

    A droplet-based microreactor was used for synthesis of water-soluble Ag2S quantum dots (QDs). Monodispersed Ag2S nanoparticles with a surface of carboxylic acid-terminated were synthesized in the droplet microreactor. The x-ray powder diffraction results indicated products were monoclinic Ag2S nanocrystals. Furthermore, different-sized Ag2S QDs that were near-infrared-emitting or visible-emitting were continuously stably synthesized in droplet microreactors at different temperatures. We believe we offer a new method for obtaining different-sized Ag2S nanoparticles.

  18. Droplet-based microreactor for synthesis of water-soluble Ag₂S quantum dots.

    Science.gov (United States)

    Shu, Yun; Jiang, Peng; Pang, Dai-Wen; Zhang, Zhi-Ling

    2015-07-10

    A droplet-based microreactor was used for synthesis of water-soluble Ag2S quantum dots (QDs). Monodispersed Ag2S nanoparticles with a surface of carboxylic acid-terminated were synthesized in the droplet microreactor. The x-ray powder diffraction results indicated products were monoclinic Ag2S nanocrystals. Furthermore, different-sized Ag2S QDs that were near-infrared-emitting or visible-emitting were continuously stably synthesized in droplet microreactors at different temperatures. We believe we offer a new method for obtaining different-sized Ag2S nanoparticles. PMID:26067160

  19. A dual-core double emulsion platform for osmolarity-controlled microreactor triggered by coalescence of encapsulated droplets.

    Science.gov (United States)

    Guan, Xuewei; Hou, Likai; Ren, Yukun; Deng, Xiaokang; Lang, Qi; Jia, Yankai; Hu, Qingming; Tao, Ye; Liu, Jiangwei; Jiang, Hongyuan

    2016-05-01

    Droplet-based microfluidics has provided a means to generate multi-core double emulsions, which are versatile platforms for microreactors in materials science, synthetic biology, and chemical engineering. To provide new opportunities for double emulsion platforms, here, we report a glass capillary microfluidic approach to first fabricate osmolarity-responsive Water-in-Oil-in-Water (W/O/W) double emulsion containing two different inner droplets/cores and to then trigger the coalescence between the encapsulated droplets precisely. To achieve this, we independently control the swelling speed and size of each droplet in the dual-core double emulsion by controlling the osmotic pressure between the inner droplets and the collection solutions. When the inner two droplets in one W/O/W double emulsion swell to the same size and reach the instability of the oil film interface between the inner droplets, core-coalescence happens and this coalescence process can be controlled precisely. This microfluidic methodology enables the generation of highly monodisperse dual-core double emulsions and the osmolarity-controlled swelling behavior provides new stimuli to trigger the coalescence between the encapsulated droplets. Such swelling-caused core-coalescence behavior in dual-core double emulsion establishes a novel microreactor for nanoliter-scale reactions, which can protect reaction materials and products from being contaminated or released. PMID:27279935

  20. Fast Enzymatic Processing of Proteins for MS Detection with a Flow-through Microreactor.

    Science.gov (United States)

    Lazar, Iulia M; Deng, Jingren; Smith, Nicole

    2016-01-01

    The vast majority of mass spectrometry (MS)-based protein analysis methods involve an enzymatic digestion step prior to detection, typically with trypsin. This step is necessary for the generation of small molecular weight peptides, generally with MW microreactor with immobilized enzymes or of a range of complementary physical processes that reduce the time necessary for proteolytic digestion to a few minutes (e.g., microwave or high-pressure). In this work, we describe a simple and cost-effective approach that can be implemented in any laboratory for achieving fast enzymatic digestion of a protein. The protein (or protein mixture) is adsorbed on C18-bonded reversed-phase high performance liquid chromatography (HPLC) silica particles preloaded in a capillary column, and trypsin in aqueous buffer is infused over the particles for a short period of time. To enable on-line MS detection, the tryptic peptides are eluted with a solvent system with increased organic content directly in the MS ion source. This approach avoids the use of high-priced immobilized enzyme particles and does not necessitate any aid for completing the process. Protein digestion and complete sample analysis can be accomplished in less than ~3 min and ~30 min, respectively. PMID:27078683

  1. Advances in polymer synthesis in microreactors%微反应器内聚合物合成研究进展

    Institute of Scientific and Technical Information of China (English)

    骆广生; 王凯; 王佩坚; 吕阳成

    2014-01-01

    微反应器作为化学工程学科的前沿和热点方向,逐渐成为聚合物合成的新装备、新工艺与新产品开发的重要平台,得到学术界和产业界的广泛关注。微反应器可实现可控的多相微尺度流动,能够强化聚合反应中的混合、传质和传热过程,严格控制反应时间,实现反应单元的模块化组合。与传统搅拌反应器相比,这些特点使得微反应器在控制聚合物分子量分布,简化反应环境,提高反应选择性,调节聚合物分子结构和宏观形貌等方面展现出了一定优势。本文全面综述了聚合物合成微反应器理论和技术的研究进展,并在新过程和新产品开发、反应动力学测量、微尺度基础研究和反应器放大等方面进行了展望。%Microreactor is a frontier and hot topic in the research of chemical engineering. It is an important platform of polymer synthesis in the development of new equipment, new technology, and new product, drawing attentions from academia and industry. Microreactors make possible well-controlled multi-phase flow, intensified mixing and mass/heat transport process, strictly-controlled reaction time, and modularized configuration in polymerization reactions. Comparing with the common batch reactors, some advantages of microreactors are producing polymeric materials with narrow molecular weight distribution, adjustable molecular architecture, or controlled macroscopic structure. In this review, the theoretical and technological advances in polymer synthesis using microreactors are introduced. Some further research issues are also discussed, including developing new polymerization process and new polymer product, measuring reaction kinetics, exploring chemical engineering fundamentals at micrometer scale, and scaling up the microreactor.

  2. Bio-inspired immobilization of metal oxides on monolithic microreactor for continuous Knoevenagel reaction.

    Science.gov (United States)

    Song, Wentong; Shi, Da; Tao, Shengyang; Li, Zhaoliang; Wang, Yuchao; Yu, Yongxian; Qiu, Jieshan; Ji, Min; Wang, Xinkui

    2016-11-01

    A facile method is reported to construct monolithic microreactor with high catalytic performance for Knoevenagel reaction. The microreactor is based on hierarchically porous silica (HPS) which has interconnected macro- and mesopores. Then the HPS is surface modified by pyrogallol (PG) polymer. Al(NO3)3 and Mg(NO3)2 are loaded on the surface of HPS through coordination with -OH groups of PG. After thermal treatment, Al(NO3)3 and Mg(NO3)2 are converted Al2O3 and MgO. The as-synthesized catalytic microreactor shows a high and stable performance in Knoevenagel reaction. The microreactor possess large surface area and interconnected pore structures which are beneficial for reactions. Moreover, this economic, facile and eco-friendly surface modification method can be used in loading more metal oxides for more reactions. PMID:27459172

  3. Effect of surface condition on the flow in segmented gas-liquid microreactors

    Science.gov (United States)

    Pouya, Shahram; Koochesfahani, Manoochehr

    2010-11-01

    The mixing process within segmented gas-liquid microreactors is of significance importance in design and optimization of devices for high throughput material synthesis. In a typical slug flow regime the liquid slugs are connected through a thin liquid film that plays an important role in hydrodynamics of the microreactor flow. Among the parameters that can influence the thin film layer, and the overall flow, is the surface condition of microchannel walls. We present preliminary results of this influence in the segmented gas-liquid flow of Ethanol/Nitrogen within PDMS microreactors. The results are presented specifically for microreactors with different level of roughness on the channel walls. The range of stable slug flow regime and behavior of liquid film are studied as a function of surface roughness.

  4. Mathematical Modeling of Biosensors Based on an Array of Enzyme Microreactors

    Science.gov (United States)

    Baronas, Romas; Ivanauskas, Feliksas; Kulys, Juozas

    2006-01-01

    This paper presents a two-dimensional-in-space mathematical model of biosensors based on an array of enzyme microreactors immobilised on a single electrode. The modeling system acts under amperometric conditions. The microreactors were modeled by particles and by strips. The model is based on the diffusion equations containing a non-linear term related to the Michaelis-Menten kinetics of the enzymatic reaction. The model involves three regions: an array of enzyme microreactors where enzyme reaction as well as mass transport by diffusion takes place, a diffusion limiting region where only the diffusion takes place, and a convective region, where the analyte concentration is maintained constant. Using computer simulation, the influence of the geometry of the microreactors and of the diffusion region on the biosensor response was investigated. The digital simulation was carried out using the finite difference technique.

  5. Mathematical Modeling of Biosensors Based on an Array of Enzyme Microreactors

    Directory of Open Access Journals (Sweden)

    Juozas Kulys

    2006-04-01

    Full Text Available This paper presents a two-dimensional-in-space mathematical model ofbiosensors based on an array of enzyme microreactors immobilised on a single electrode.The modeling system acts under amperometric conditions. The microreactors were modeledby particles and by strips. The model is based on the diffusion equations containing a non-linear term related to the Michaelis-Menten kinetics of the enzymatic reaction. The modelinvolves three regions: an array of enzyme microreactors where enzyme reaction as well asmass transport by diffusion takes place, a diffusion limiting region where only the diffusiontakes place, and a convective region, where the analyte concentration is maintained constant.Using computer simulation, the influence of the geometry of the microreactors and of thediffusion region on the biosensor response was investigated. The digital simulation wascarried out using the finite difference technique.

  6. Microreactor Technology for the On-Site Production of Methyl Chloride

    Czech Academy of Sciences Publication Activity Database

    Schmidt, S.A.; Vajglová, Zuzana; Eränen, K.; Murzin, D.Y.; Salmi, T.

    Vol. Session 7. -, 2014, KN-7. ISBN N. [International Congress on Green Process Engineering /4./. Sevilla (ES), 07.04.2014-10.04.2014] Institutional support: RVO:67985858 Keywords : chloromethane * intensification * microreactor http://www.gpe2014.org/

  7. Experimental and modelling aspects of nitrogen oxide reduction in mini- and microreactors

    Energy Technology Data Exchange (ETDEWEB)

    Hernandez Carucci, J.R.

    2009-07-01

    Following the concept of process intensification, a sharp increase in the fabrication and testing of novel microstructured devices in the sub-millimetre range for chemical reaction engineering has occurred during the last two decades. As a consequence, chemical transformations that were once performed in conventional vessels have been accomplished in microreactors. Drastic improvements in energy efficiency and enhancements in heat and mass transfer capabilities have been achieved by rethinking processes as a whole. Microreactors are notorious for providing precisely defined conditions, even on a laboratory scale. Moreover, sustainable solutions of various types have been investigated for the foreseen energy crisis. Bio-derived fuels are regarded as an alternative for energy production in the near future, especially in the transportation sector, where biodiesels have already been tested and used. While the use of bio-produced fuels is suggested to reduce the total carbon dioxide release in the atmosphere, such fuels, when combusted, produce more nitrogen oxides NO{sub x} (NO and NO{sub 2}), than conventional fossil-derived fuels. Additionally, the higher content of alkali species (Na and K) and P in bio-derived fuels represents a technological challenge. For stationary sources, the effect of alkali vapours (Na, K) in the reduction of NO{sub x} during the combustion of different biomasses, e.g., black liquor, Swedish wood and Danish straw, relevant in fixed bed reactors and recovery boilers, was theoretically investigated. A detailed H/C/O/N/Na/K mechanism consisting of 350 reactions among 60 species was implemented in the commercial software Chemkin 4.0. The presence of the alkali species was found to enhance the NO{sub x} reduction efficiency in the studied conditions. A simplified reaction scheme for the Na and K species influencing the NO{sub x} reduction was proposed. For the case of mobile sources, the hydrocarbon-assisted selective catalytic reduction of NO

  8. First Experiments on a Microreactor Created by Proton Microbeam

    International Nuclear Information System (INIS)

    Complete text of publication follows. Microreactors are innovative and promising tools in technology nowadays because of their advantages compared to the conventional-scale reactors. These advantages include vast improvements in surface to volume ratio, energy efficiency, reaction speed and yield, and increased control of reaction conditions, to name a few examples. In this work we present the design of a prototype micro-electrochemical cell of 1.5 μL volume (2.5 x 2.5 x 0.240 mm) created with a 3 MeV proton microbeam. We deposited gold electrodes on the bottom and top sides of the chamber. The cell can be separated into two half-cells with a suitable membrane applicable to galvanic or fuel cells as well. We used a polycapillary film (also made by PBW ourselves) to separate the two half-cells, hindering the mixing of the anolyte and catholyte solutions. Fig. 1. shows the 3D model of the designed structure. Fig. 2. shows the assembled microreactor with the attached pipes. Measuring a detectable current driven between the two electrodes in this microelectrochemical cell containing a simple electrolyte solution demonstrates an operating device. As a result of the minimal mixing caused by the polycapillary film, this cell design can be suitable for electro-synthesis. At 1 V potential the measured current was about 150-200 μA, at 2 V it was about 250-400 μA. After charging the cell with direct current for a while, it was found to act as a micro battery due to the changes of the starting concentration of the NaOH electrolyte and the formation of products in the anolyte and catholyte solutions. After five minutes of charging with 1 V, the measured voltage potential of electrodes was about 20 mV for a few minutes with slowly decreasing current. Due to the micromachining technique's high resolution, further reduction of the dimensions of this kind of microreactor is also planned. Acknowledgements The technical assistance of the Van de Graaff accelerator operating staff

  9. Thermoelectric generation coupling methanol steam reforming characteristic in microreactor

    International Nuclear Information System (INIS)

    Thermoelectric (TE) generator converts heat to electric energy by thermoelectric material. However, heat removal on the cold side of the generator represents a serious challenge. To address this problem and for improved energy conversion, a thermoelectric generation process coupled with methanol steam reforming (SR) for hydrogen production is designed and analyzed in this paper. Experimental study on the cold spot character in a micro-reactor with monolayer catalyst bed is first carried out to understand the endothermic nature of the reforming as the thermoelectric cold side. A novel methanol steam reforming micro-reactor heated by waste heat or methanol catalytic combustion for hydrogen production coupled with a thermoelectric generation module is then simulated. Results show that the cold spot effect exists in the catalyst bed under all conditions, and the associated temperature difference first increases and then decreases with the inlet temperature. In the micro-reactor, the temperature difference between the reforming and heating channel outlets decreases rapidly with an increase in thermoelectric material's conductivity coefficient. However, methanol conversion at the reforming outlet is mainly affected by the reactor inlet temperature; while at the combustion outlet, it is mainly affected by the reactor inlet velocity. Due to the strong endothermic effect of the methanol steam reforming, heat supply of both kinds cannot balance the heat needed at reactor local areas, resulting in the cold spot at the reactor inlet. When the temperature difference between the thermoelectric module's hot and cold sides is 22 K, the generator can achieve an output voltage of 55 mV. The corresponding molar fraction of hydrogen can reach about 62.6%, which corresponds to methanol conversion rate of 72.6%. - Highlights: • Cold spot character of methanol steam reforming was studied through experiment. • Thermoelectric generation Coupling MSR process has been

  10. Production of RAFT imprinted smart hydrogel particles in a continuous flow micro-reactor

    OpenAIRE

    Machado, Carla; Freitas, Ana; Kadhirvel, Porkodi; Dias, Rolando; Costa, Mário

    2014-01-01

    Feasibility of the production of RAFT imprinted smart hydrogel particles in continuous flow micro-reactor is here showed. Microfluidic continuous operation was combined with RAFT polymerization and molecular imprinting tecniques involving selected template molecules. New strategies for the production of advanced materials with tailored properties are thus developed. Particles syntetized in the continuous flow micro-reactor (set-up scheme depicted in the graphical abstract) were purified and c...

  11. Oxidation of Volatile Organic Compounds in a Multifunctional High Temperature and High-Pressure Cassette Microreactor

    OpenAIRE

    VAJGLOVÁ, Zuzana

    2013-01-01

    Analysis of the total oxidation of ethanol including reaction intermediates data obtained in the examined reactors on the temperature showed that differentmaterial applied in the construction of reactors and their arrangement give slightly different results of catalyst testing, the ones obtained from microreactor being more precise. More precise control of reaction temperature due to higher heat transfer capabilities and limited backmixing of reaction mixture in a packed bed microreactor is...

  12. Hydrodynamic and Heat Transfer Model of a Gas-Liquid Microreactor

    OpenAIRE

    Křišťál, Jiří

    2012-01-01

    In this contribution we present a hydrodynamic and heat transfer model of a microreactor for a gas-liquid reaction. In the course of formulation of the model, we considered the characteristic features of the studied system – the gas-liquid flow pattern and the change in physical properties induced by pressure and temperature variation along the microreactor. Based on the input information (gas and liquid flow rates, compositions, temperatures), the model calculates the two-phase pressure dr...

  13. Piperazine-containing polymer brush layer as supported base catalyst in a glass microreactor

    OpenAIRE

    Munirathinam, Rajesh; Huskens, Jurriaan; Verboom, Willem

    2014-01-01

    The covalent attachment of piperazine onto the inner walls of a microreactor using glycidyl methacrylate polymer brushes has been demonstrated. The piperazine-containing polymer brushes were first grown on a flat silicon oxide surface and were characterized by contact angle, Fourier transform infrared (FT-IR), ellipsometry, and X-ray photoelectron spectroscopy (XPS). The applicability of the catalytic polymer brushes in a microreactor was demonstrated for the Knoevenagel and nitroaldol conden...

  14. Special Issue: Design and Engineering of Microreactor and Smart-Scaled Flow Processes

    OpenAIRE

    Volker Hessel

    2014-01-01

    Reaction-oriented research in flow chemistry and microreactor has been extensively focused upon in special journal issues and books. On a process level, this resembled the “drop-in” (retrofit) concept with the microreactor replacing a conventional (batch) reactor. Meanwhile, with the introduction of the mobile, compact, modular container technology, the focus is more on the process side, including also providing an end-to-end vision of intensified process design. Exactly this is the focus of ...

  15. High Performance Microreactor for Rapid Fluid Mixing and Redox Reaction of Ascorbic Acid

    OpenAIRE

    Fang, Wei-Feng; Yang, J T

    2008-01-01

    Submitted on behalf of EDA Publishing Association (http://irevues.inist.fr/handle/2042/16838) International audience A novel micro device with a mechanism of split and recombination (SNR) for rapid fluidic mixing and reaction, named a SNR micro-reactor, was designed, fabricated and systematically analyzed. This SNR micro-reactor possessing an in-plane dividing structure requires only simple fabrication. We investigated this reactor and compared it numerically and experimentally with a s...

  16. Polymer End Group Modifications and Polymer Conjugations via " Click" Chemistry Employing Microreactor Technology

    OpenAIRE

    Vandenbergh, Joke; Tura, Tiago; Baeten, Evelien; Junkers, Thomas

    2014-01-01

    This study presents the development of microreactor protocols for the successful continuous flow end group modification of atom transfer radical polymerization precursor polymers into azide end-capped materials and the subsequent copper-catalyzed azide alkyne click reactions with alkyne polymers, in flow. By using a microreactor, the reaction speed of the azidation of poly(butyl acrylate), poly(methyl acrylate), and polystyrene can be accelerated from hours to seconds and full end group conve...

  17. Multi-Temperature Zone, Droplet-based Microreactor for Increased Temperature Control in Nanoparticle Synthesis

    KAUST Repository

    Erdem, E. Yegân

    2013-12-12

    Microreactors are an emerging technology for the controlled synthesis of nanoparticles. The Multi-Temperature zone Microreactor (MTM) described in this work utilizes thermally isolated heated and cooled regions for the purpose of separating nucleation and growth processes as well as to provide a platform for a systematic study on the effect of reaction conditions on nanoparticle synthesis. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Evaluation of contaminant removal of reverse osmosis and advanced oxidation in full-scale operation by combining passive sampling with chemical analysis and bioanalytical tools.

    Science.gov (United States)

    Escher, Beate I; Lawrence, Michael; Macova, Miroslava; Mueller, Jochen F; Poussade, Yvan; Robillot, Cedric; Roux, Annalie; Gernjak, Wolfgang

    2011-06-15

    Advanced water treatment of secondary treated effluent requires stringent quality control to achieve a water quality suitable for augmenting drinking water supplies. The removal of micropollutants such as pesticides, industrial chemicals, endocrine disrupting chemicals (EDC), pharmaceuticals, and personal care products (PPCP) is paramount. As the concentrations of individual contaminants are typically low, frequent analytical screening is both laborious and costly. We propose and validate an approach for continuous monitoring by applying passive sampling with Empore disks in vessels that were designed to slow down the water flow, and thus uptake kinetics, and ensure that the uptake is only marginally dependent on the chemicals' physicochemical properties over a relatively narrow molecular size range. This design not only assured integrative sampling over 27 days for a broad range of chemicals but also permitted the use of a suite of bioanalytical tools as sum parameters, representative of mixtures of chemicals with a common mode of toxic action. Bioassays proved to be more sensitive than chemical analysis to assess the removal of organic micropollutants by reverse osmosis, followed by UV/H₂O₂ treatment, as many individual compounds fell below the quantification limit of chemical analysis, yet still contributed to the observed mixture toxicity. Nonetheless in several cases, the responses in the bioassays were also below their quantification limits and therefore only three bioassays were evaluated here, representing nonspecific toxicity and two specific end points for estrogenicity and photosynthesis inhibition. Chemical analytical techniques were able to quantify 32 pesticides, 62 PCPPs, and 12 EDCs in reverse osmosis concentrate. However, these chemicals could explain only 1% of the nonspecific toxicity in the Microtox assay in the reverse osmosis concentrate and 0.0025% in the treated water. Likewise only 1% of the estrogenic effect in the E-SCREEN could be

  19. A high efficiency microfluidic-based photocatalytic microreactor using electrospun nanofibrous TiO2 as a photocatalyst

    Science.gov (United States)

    Meng, Zhaoxu; Zhang, Xu; Qin, Jianhua

    2013-05-01

    We present a novel microfluidic-based photocatalytic microreactor by using electrospun nanofibrous TiO2 as a photocatalyst for the first time. The microreactor exhibits not only a simple fabrication process, but also much higher photocatalytic activity than that achieved by a TiO2 film microreactor.We present a novel microfluidic-based photocatalytic microreactor by using electrospun nanofibrous TiO2 as a photocatalyst for the first time. The microreactor exhibits not only a simple fabrication process, but also much higher photocatalytic activity than that achieved by a TiO2 film microreactor. Electronic supplementary information (ESI) available. See DOI: 10.1039/c3nr00775h

  20. Streptavidin-functionalized capillary immune microreactor for highly efficient chemiluminescent immunoassay

    Energy Technology Data Exchange (ETDEWEB)

    Yang Zhanjun [State Key Laboratory of Analytical Chemistry for Life Science, Department of Chemistry, Nanjing University, Nanjing 210093 (China); College of Chemistry and Engineering, Yangzhou University, 88 South University Avenue, Yangzhou 225002 (China); Zong Chen [State Key Laboratory of Analytical Chemistry for Life Science, Department of Chemistry, Nanjing University, Nanjing 210093 (China); Ju Huangxian, E-mail: hxju@nju.edu.cn [State Key Laboratory of Analytical Chemistry for Life Science, Department of Chemistry, Nanjing University, Nanjing 210093 (China); Yan Feng, E-mail: yanfeng2007@sohu.com [Jiangsu Institute of Cancer Prevention and Cure, Nanjing 210009 (China)

    2011-11-07

    Highlights: {yields} A novel capillary immune microreactor was proposed for highly efficient flow-through chemiluminescent immunoassay. {yields} The microreactor was prepared by functionalizing capillary inner wall with streptavidin for capture of biotinylated antibody. {yields} The proposed immunoassay method showed wide dynamic range, good reproducibility, stability and practicality. {yields} The microreactor was low-cost and disposable, and possessed several advantages over the conventional immunoreactors. - Abstract: A streptavidin functionalized capillary immune microreactor was designed for highly efficient flow-through chemiluminescent (CL) immunoassay. The functionalized capillary could be used as both a support for highly efficient immobilization of antibody and a flow cell for flow-through immunoassay. The functionalized inner wall and the capture process were characterized using scanning electron microscopy. Compared to conventional packed tube or thin-layer cell immunoreactor, the proposed microreactor showed remarkable properties such as lower cost, simpler fabrication, better practicality and wider dynamic range for fast CL immunoassay with good reproducibility and stability. Using {alpha}-fetoprotein as model analyte, the highly efficient CL flow-through immunoassay system showed a linear range of 3 orders of magnitude from 0.5 to 200 ng mL{sup -1} and a low detection limit of 0.1 ng mL{sup -1}. The capillary immune microreactor could make up the shortcoming of conventional CL immunoreactors and provided a promising alternative for highly efficient flow-injection immunoassay.

  1. Microbial Reverse-Electrodialysis Electrolysis and Chemical-Production Cell for H2 Production and CO2 Sequestration.

    Science.gov (United States)

    Zhu, Xiuping; Hatzell, Marta C; Logan, Bruce E

    2014-04-01

    Natural mineral carbonation can be accelerated using acid and alkali solutions to enhance atmospheric CO2 sequestration, but the production of these solutions needs to be carbon-neutral. A microbial reverse-electrodialysis electrolysis and chemical-production cell (MRECC) was developed to produce these solutions and H2 gas using only renewable energy sources (organic matter and salinity gradient). Using acetate (0.82 g/L) as a fuel for microorganisms to generate electricity in the anode chamber (liquid volume of 28 mL), 0.45 mmol of acid and 1.09 mmol of alkali were produced at production efficiencies of 35% and 86%, respectively, along with 10 mL of H2 gas. Serpentine dissolution was enhanced 17-87-fold using the acid solution, with approximately 9 mL of CO2 absorbed and 4 mg of CO2 fixed as magnesium or calcium carbonates. The operational costs, based on mineral digging and grinding, and water pumping, were estimated to be only $25/metric ton of CO2 fixed as insoluble carbonates. Considering the additional economic benefits of H2 generation and possible wastewater treatment, this method may be a cost-effective and environmentally friendly method for CO2 sequestration. PMID:24741666

  2. Microbial Reverse-Electrodialysis Electrolysis and Chemical-Production Cell for H2 Production and CO2 Sequestration.

    KAUST Repository

    Zhu, Xiuping

    2014-03-24

    Natural mineral carbonation can be accelerated using acid and alkali solutions to enhance atmospheric CO2 sequestration, but the production of these solutions needs to be carbon-neutral. A microbial reverse-electrodialysis electrolysis and chemical-production cell (MRECC) was developed to produce these solutions and H2 gas using only renewable energy sources (organic matter and salinity gradient). Using acetate (0.82 g/L) as a fuel for microorganisms to generate electricity in the anode chamber (liquid volume of 28 mL), 0.45 mmol of acid and 1.09 mmol of alkali were produced at production efficiencies of 35% and 86%, respectively, along with 10 mL of H2 gas. Serpentine dissolution was enhanced 17-87-fold using the acid solution, with approximately 9 mL of CO2 absorbed and 4 mg of CO2 fixed as magnesium or calcium carbonates. The operational costs, based on mineral digging and grinding, and water pumping, were estimated to be only $25/metric ton of CO2 fixed as insoluble carbonates. Considering the additional economic benefits of H2 generation and possible wastewater treatment, this method may be a cost-effective and environmentally friendly method for CO2 sequestration.

  3. Effluent treatment from hot laundry of Instalacao Nuclear de Agua Pressurizada (INAP), by chemical precipitation processes and reverse osmosis

    International Nuclear Information System (INIS)

    Among the many types of radioactive effluents which will be generated at the Instalacao Nuclear de Agua Pressurizada (INAP), that is in development by the Centro Tecnologico da Marinha em Sao Paulo (CTMSP), there is a specific one, arising from the laundry of this facility. Besides the presence of traces of radioactive materials in this effluent, it is present in its composition a significant quantify of detergent, difficulting its treatment by the techniques usually employed in the effluents treatment systems of nuclear facilities and consequently its release to the environment. In this work, a synthetic solution was prepared based on data available in literature and project documentation of the laundry of INAP. It was studied the treatment of this effluent by chemical precipitation with calcium oxide and reverse osmosis treatment. The results got during the treatment assays showed that the used processes are efficient to treat the effluent that will be generated at the laundry of INAP, obtaining a purified stream, that represents 90% of the effluent fed at the treatment system, with a higher quality than the water used for industrial processes, becoming its reutilisation in the water used for industrial processes, becoming its reutilisation in the INAP feasible, minimizing any negative impact to the environment. (author)

  4. The silicon-glass microreactor with embedded sensors—technology and results of preliminary qualitative tests, toward intelligent microreaction plant

    Science.gov (United States)

    Knapkiewicz, P.

    2013-03-01

    The technology and preliminary qualitative tests of silicon-glass microreactors with embedded pressure and temperature sensors are presented. The concept of microreactors for leading highly exothermic reactions, e.g. nitration of hydrocarbons, and design process-included computer-aided simulations are described in detail. The silicon-glass microreactor chip consisting of two micromixers (multistream micromixer), reaction channels, cooling/heating chambers has been proposed. The microreactor chip was equipped with a set of pressure and temperature sensors and packaged. Tests of mixing quality, pressure drops in channels, heat exchange efficiency and dynamic behavior of pressure and temperature sensors were documented. Finally, two applications were described.

  5. The silicon–glass microreactor with embedded sensors—technology and results of preliminary qualitative tests, toward intelligent microreaction plant

    International Nuclear Information System (INIS)

    The technology and preliminary qualitative tests of silicon–glass microreactors with embedded pressure and temperature sensors are presented. The concept of microreactors for leading highly exothermic reactions, e.g. nitration of hydrocarbons, and design process-included computer-aided simulations are described in detail. The silicon–glass microreactor chip consisting of two micromixers (multistream micromixer), reaction channels, cooling/heating chambers has been proposed. The microreactor chip was equipped with a set of pressure and temperature sensors and packaged. Tests of mixing quality, pressure drops in channels, heat exchange efficiency and dynamic behavior of pressure and temperature sensors were documented. Finally, two applications were described. (paper)

  6. Energy storage for a lunar base by the reversible chemical reaction: CaO+H2O reversible reaction Ca(OH)2

    Science.gov (United States)

    Perez-Davis, Marla E.; Difilipo, Frank

    1990-01-01

    A thermochemical solar energy storage concept involving the reversible reaction CaO + H2O yields Ca(OH)2 is proposed as a power system element for a lunar base. The operation and components of such a system are described. The CaO/H2O system is capable of generating electric power during both the day and night. The specific energy (energy to mass ratio) of the system was estimated to be 155 W-hr/kg. Mass of the required amount of CaO is neglected since it is obtained from lunar soil. Potential technical problems, such as reactor design and lunar soil processing, are reviewed.

  7. 100t/h反渗透膜化学清洗总结%A summary of 100 t/h chemical cleaning of reverse osmosis membrane

    Institute of Scientific and Technical Information of China (English)

    毛建新

    2012-01-01

    针对脱盐水装置反渗透膜运行一段时间后出现的因细菌繁殖、结垢造成浓水侧堵塞,产水量下降,进水压力升高等问题,对反渗透膜进行了化学清洗。%This paper focuses on chemical cleaning reverse osmosis membrane, to deal with the problems such as water production decreased, inlet pressure due to bacterial reproduction, fouling caused by concentrated water side plug for a period after the process of water desalination unit operation of reverse osmosis.

  8. In-Situ Growth of Carbon Nanotubes in a Microreactor Environment

    Science.gov (United States)

    Kona, Silpa; Harnett, Cindy

    2010-03-01

    This work presents an approach to the in-situ growth of Carbon Nanotubes (CNTs) inside a micro scale environment using thermal chemical vapor deposition technique (Thermal CVD). Microreactors provide an ideal environment for exploration of extreme nanomaterial growth conditions, because they provide homogenous reactant temperature and concentrations, and the ability to work safely and economically at high temperatures and pressures over a broad range of flows. The study of Carbon Nanotube synthesis inside sub-mm channels and microfabricated reactors is of interest both fundamentally and for applications such as chromatographic channels. Carbon nanotubes (CNTs) are also excellent materials to be used as gas sensing elements as they exhibit changes in their electronic properties on being exposed to gases and are of interest in developing gas sensors operating at room temperature. Such micro scale CNT based sensing devices offer several practical advantages over the current sensors designs available, along with opening up avenues for a more efficient and better way of sensing gases.

  9. Glucose microfluidic biosensors based on reversible enzyme immobilization on photopatterned stimuli-responsive polymer.

    Science.gov (United States)

    Xiong, Meng; Gu, Bin; Zhang, Jia-Dong; Xu, Jing-Juan; Chen, Hong-Yuan; Zhong, Hui

    2013-12-15

    In this paper, we demonstrate a new strategy for replaceable enzymatic microreactor based on a switchable wettability interface of poly(N-isopropylacrylamide) (PNIPAAm). PNIPAAm porous polymer monolith (PPM) with 3D macroporous framework is photopolymerized in glass microchip within 30 s. The PNIPAAm PPM not only shows its reversible swelling/shrinking property at the different temperature around the lower critical solution temperature (LCST), but also shows reversible hydrophilicity/hydrophobicity corresponding to its swelling/shrinking status. Based on these properties, a biocompatible and replaceable on-chip enzymatic microreactor has been successfully built by means of the reversible adsorption and release of glucose oxidase (GOx) on the robust and stable matrix. Coupled with a carbon fiber microelectrode as electrochemical detector, the microreactor has been successfully employed for detection of glucose with a linear range from 0.05 to 5 mM. This approach may provide a promising way for high efficient and renewable microreactors that will find wide application in clinical diagnosis, biochemical synthesis/analysis, and proteomic research. PMID:23867353

  10. High Performance Microreactor for Rapid Fluid Mixing and Redox Reaction of Ascorbic Acid

    CERN Document Server

    Fang, Wei-Feng

    2008-01-01

    A novel micro device with a mechanism of split and recombination (SNR) for rapid fluidic mixing and reaction, named a SNR micro-reactor, was designed, fabricated and systematically analyzed. This SNR micro-reactor possessing an in-plane dividing structure requires only simple fabrication. We investigated this reactor and compared it numerically and experimentally with a slanted-groove micromixer (SGM). From the numerical results the mixing indices and mixing patterns demonstrated that the mixing ability of the SNR micro-reactor was much superior to that of the SGM. From a mixing test with phenolphthalein and sodium hydroxide solutions, the mixing lengths of the SNR micro-reactor were less than 4 mm for a Reynolds number over a wide range (Re = 0.1 - 10). From a comparison of mixing lengths, the results revealed also that the SNR micro-reactor surpassed the SGM in mixing performance by more than 200 %. As a reaction length is a suitable test of the performance of a reactor, we introduced a redox reaction betwe...

  11. High quantum yield ZnO quantum dots synthesizing via an ultrasonication microreactor method.

    Science.gov (United States)

    Yang, Weimin; Yang, Huafang; Ding, Wenhao; Zhang, Bing; Zhang, Le; Wang, Lixi; Yu, Mingxun; Zhang, Qitu

    2016-11-01

    Green emission ZnO quantum dots were synthesized by an ultrasonic microreactor. Ultrasonic radiation brought bubbles through ultrasonic cavitation. These bubbles built microreactor inside the microreactor. The photoluminescence properties of ZnO quantum dots synthesized with different flow rate, ultrasonic power and temperature were discussed. Flow rate, ultrasonic power and temperature would influence the type and quantity of defects in ZnO quantum dots. The sizes of ZnO quantum dots would be controlled by those conditions as well. Flow rate affected the reaction time. With the increasing of flow rate, the sizes of ZnO quantum dots decreased and the quantum yields first increased then decreased. Ultrasonic power changed the ultrasonic cavitation intensity, which affected the reaction energy and the separation of the solution. With the increasing of ultrasonic power, sizes of ZnO quantum dots first decreased then increased, while the quantum yields kept increasing. The effect of ultrasonic temperature on the photoluminescence properties of ZnO quantum dots was influenced by the flow rate. Different flow rate related to opposite changing trend. Moreover, the quantum yields of ZnO QDs synthesized by ultrasonic microreactor could reach 64.7%, which is higher than those synthesized only under ultrasonic radiation or only by microreactor. PMID:27245962

  12. Amphiphilic polymeric micelles as microreactors: improving the photocatalytic hydrogen production of the [FeFe]-hydrogenase mimic in water.

    Science.gov (United States)

    Wang, Feng; Wen, Min; Feng, Ke; Liang, Wen-Jing; Li, Xu-Bing; Chen, Bin; Tung, Chen-Ho; Wu, Li-Zhu

    2016-01-11

    An amphiphilic polymeric micelle is utilized as a microreactor to load a hydrophobic [FeFe]-hydrogenase mimic in water. The local concentration enhancement and strong interaction between the mimic and the photosensitizer as well as the water-mediated fast proton migration caused by the microreactor improve photocatalytic hydrogen production remarkably in water. PMID:26442776

  13. On-chip microreactor system for the production of nano-emulsion loaded liposomes: towards targeted delivery of lipophilic drugs

    NARCIS (Netherlands)

    Langelaan, M.L.P.; Emmelkamp, J.; Segers, M.J.A.; Lenting, H.B.M.

    2011-01-01

    An on-chip microreactor system for the production of novel nano-biodevices is presented. This nano-biodevice consists of a nano-emulsion loaded with lipophilic drugs, entrapped in liposomes. These nano-biodevices can be equipped with targeting molecules for higher drug efficiency. The microreactor s

  14. The Inherent Reactor Kinetics for Transformation of Geniposidic Acid from Geniposide in a Microreactor

    Directory of Open Access Journals (Sweden)

    Chiu-Lan Hsieh

    2015-01-01

    Full Text Available The ripe fruits of Gardenia jasminoides Ellis (Rubiaceae (GJ are widely used in chemical, food and medicinal industries. Crocin and geniposide, the main constituents of GJ, have shown a diversity of biological activities including sedative, anti-inflammatory and antipyretic. We propose some new bioactive chemicals could be derived from geniposide. The optimum transformation condition of geniposide into geniposidic acid still remains unclear. In order to develop a reactor, the information about the inherent reaction kinetics is required. In a microreactor (V =62.8 mL, geniposide (0.01 mole/L, 20 mL and NaOH (0.1 equivalent/L, pH=13, 10mL were left to react at 80, 70, 60, 50, and 40 oC and tracked with HPLC. Results indicated that the reaction obeyed the pseudo-first order kinetics, the corresponding pseudo-first order rate constants ( 1 k ' were 11.064 h -1 , 8.682 h -1 , 2.400 h -1 , 1.021 h -1 , and 0.750 h-1 , and the fractional conversions were 73.4%, 60.5%, 38.6%, 43.6%, and 51.8% at 0.50, 0.50, 0.833, 1.00, and 2.00 h. The energy of activation was 8.751 kJ mol-1 . Conclusively, this transformation obeys the pseudo-first order kinetics with a low energy of activation, 8.751 kJ mol-1 . The optimum transformations at 80oC and 70oC for 0.5 h were 73.4% and 60.5%, respectively.

  15. Nano-magnetic particles as multifunctional microreactor for deep desulfurization

    Energy Technology Data Exchange (ETDEWEB)

    Cui, Xinai; Yao, Dongdong [Engineering Research Center of Historical and Cultural Heritage Protection, Ministry of Education, School of Materials Science and Engineering, Shaanxi Normal University, Xi' an 710062 (China); Li, Hong [College of Environment and Chemical Engineering, Xi' an Polytechnic University, Xi' an 710048 (China); Yang, Juxiang [Department of Chemistry, Xi' an University of Arts and Science, Xi' an 710065 (China); Hu, Daodao, E-mail: daodaohu@snnu.edu.cn [Engineering Research Center of Historical and Cultural Heritage Protection, Ministry of Education, School of Materials Science and Engineering, Shaanxi Normal University, Xi' an 710062 (China)

    2012-02-29

    Highlights: Black-Right-Pointing-Pointer An easy-separated amphiphilic catalyst with small size was prepared for deep desulfurization. Black-Right-Pointing-Pointer The effects of several factors on desulfurization reactivity were systematically investigated. Black-Right-Pointing-Pointer The catalyst demonstrates high performance in the deep desulfurization. Black-Right-Pointing-Pointer The material could make integration of micro-reactor and micro-extractor into one system. - Abstract: Oxidation of dibenzothiophene with hydrogen peroxide using a recyclable amphiphilic catalyst has been studied. The catalyst was synthesized by surfacely covering magnetic silica nanospheres (MSN) with the complexes between 3-(trimethoxysilyl)-propyldimethyloctadecyl ammonium chloride (AEM) and phosphotungstic acid (PTA). The morphology and components of the composite material were characterized by TEM, EDX, XPS, FT-IR, and VSM, respectively. The effects of several factors on desulfurization reactivity were systematically investigated. The results showed that the composite nanospheres have core/shell structure with the properties of amphiphilicity and superparamagnetism. The composite nanospheres have high catalytic activity in the oxidation of dibenzothiophene to corresponding sulfones by hydrogen peroxide under mild reaction conditions. The sulfur level could be lowered from 487 ppm to less than 0.8 ppm under optimal conditions. Additionally, the amphiphilic catalyst and the oxidized product could be simultaneously separated from medium by external magnetism, and the recovered composite material could be recycled for three times with almost constant activity.

  16. Modelling the Hydrodynamics and Transport in Multiphase Microreactors

    Science.gov (United States)

    Yang, Lu; Shi, Yanxiang; Abolhasani, Milad; Jensen, Klavs

    2015-11-01

    Multiphase flow is prevalent in a variety of industrial applications, but the extent of these processes is often limited by the innate mass transfer resistance across phase boundaries. Microscale multiphase systems, owing to their reduced characteristic length scales, increase specific interfacial areas and unique hydrodynamic patterns, can significantly enhance the rate of mass transfer, thereby improving the efficiency of multiphase processes. However, many uncertainties still remain in the prediction of multiphase hydrodynamics and scalar transport on the microscale, primarily due to the complex nature of the multiphase flow. In this work, to elucidate the mechanism of mass transfer enhancement in microscale multiphase flows, a computational fluid dynamic (CFD) model using the volume-of-fluid (VOF) method is developed, and the method is validated with experiments. By introducing a scalar transport equation with sink/source terms using the one-fluid formulation, we enable the simultaneous capturing of multi-phase hydrodynamics, mass transfer and reactions. In tandem with the numerical simulations, we also perform mass transfer analysis of multiphase flows based on the penetration theory and a two-stage theory, which further examines the mechanism of mixing enhancement in multiphase flow, and reveals a two-fold increase in mass transfer coefficients in the microreactors compared to conventional multiphase contactors.

  17. Extracellular Microreactor for the Depletion of Phenylalanine Toward Phenylketonuria Treatment

    DEFF Research Database (Denmark)

    Rigau, Leticia Hosta; Durán, María José York; Kang, Tse Siang; Staedler, Brigitte

    2015-01-01

    Phenylketonuria (PKU) is a genetic enzyme defect affecting 1:10 000-20 000 newborn children every year. The amino acid phenylalanine (Phe) is not depleted but accumulates in tissues of several organs, which leads to severe medical conditions. A promising concept to restore the metabolism of the a...... extracellular multicompartment microreactor is reported using the relevant enzymes and settings toward the treatment of the medical condition PKU.......Phenylketonuria (PKU) is a genetic enzyme defect affecting 1:10 000-20 000 newborn children every year. The amino acid phenylalanine (Phe) is not depleted but accumulates in tissues of several organs, which leads to severe medical conditions. A promising concept to restore the metabolism of the...... affected patients will be to orally administer the defective enzyme which will remove Phe in the intestine. Herein, capsosomes, a multicompartment carrier consisting of thousands of liposomes embedded within a polymeric carrier, are employed as encapsulation platform for this purpose. It is shown that the...

  18. Nano-magnetic particles as multifunctional microreactor for deep desulfurization

    International Nuclear Information System (INIS)

    Highlights: ► An easy-separated amphiphilic catalyst with small size was prepared for deep desulfurization. ► The effects of several factors on desulfurization reactivity were systematically investigated. ► The catalyst demonstrates high performance in the deep desulfurization. ► The material could make integration of micro-reactor and micro-extractor into one system. - Abstract: Oxidation of dibenzothiophene with hydrogen peroxide using a recyclable amphiphilic catalyst has been studied. The catalyst was synthesized by surfacely covering magnetic silica nanospheres (MSN) with the complexes between 3-(trimethoxysilyl)-propyldimethyloctadecyl ammonium chloride (AEM) and phosphotungstic acid (PTA). The morphology and components of the composite material were characterized by TEM, EDX, XPS, FT-IR, and VSM, respectively. The effects of several factors on desulfurization reactivity were systematically investigated. The results showed that the composite nanospheres have core/shell structure with the properties of amphiphilicity and superparamagnetism. The composite nanospheres have high catalytic activity in the oxidation of dibenzothiophene to corresponding sulfones by hydrogen peroxide under mild reaction conditions. The sulfur level could be lowered from 487 ppm to less than 0.8 ppm under optimal conditions. Additionally, the amphiphilic catalyst and the oxidized product could be simultaneously separated from medium by external magnetism, and the recovered composite material could be recycled for three times with almost constant activity.

  19. Power conversion for a microreactor: a nuclear space application

    International Nuclear Information System (INIS)

    Generating nuclear power in space is of fundamental importance if it is desired to realize some aggressive type of exploration. Basically, at Earth orbit (either LEO or GEO) most applications tend to use solar panels, which are just fine, in spite of problems such as vibration, non optimal light incidence angle and non electricity generation due to Earth's shadow. For deep space exploration the nuclear power is been considered as a strong candidate and maybe the only one. The Institute for Advanced Studies is conducting the TERRA project that tracks the developments in the area and, also, intends to develop the key technologies that will allow such a machine to be build with indigenous technology. TERRA stands for TEcnologia de Reatores Rapidos Avancados. This project, at its first stage aims at the specification of the microreactor fuel element with its possible geometrical arrangements. Also for this stage a gas Brayton closed cycle is being considered as a heat conversion to electricity and/or propulsion effect. The basic idea is to adapt an open loop aeronautic gas turbine to operate as a closed loop gas Turbine. This arrangement will use heat pipes as a cold source, or a heat rejection passive system. Up to this point a lot has been done in terms of numerical and graphical development. It is expected that some built up will be happening during this year. An account of this work will be presented at the conference. (author)

  20. Immobilized Pepsin Microreactor for Rapid Peptide Mapping with Nanoelectrospray Ionization Mass Spectrometry

    Science.gov (United States)

    Long, Ying; Wood, Troy D.

    2015-01-01

    Most enzymatic microreactors for protein digestion are based on trypsin, but proteins with hydrophobic segments may be difficult to digest because of the paucity of Arg and Lys residues. Microreactors based on pepsin, which is less specific than trypsin, can overcome this challenge. Here, an integrated immobilized pepsin microreactor (IPMR)/nanoelectrospray emitter is examined for its potential for peptide mapping. For myoglobin, equivalent sequence coverage is obtained in a thousandth the time of solution digestion with better sequence coverage. While sequence coverage of cytochrome c is lesser than solution in this short duration, more highly-charged peptic peptides are produced and a number of peaks are unidentified at low-resolution, suggesting that high-resolution mass spectrometry is needed to take full advantage of integrated IPMR/nanoelectrospray devices.

  1. Gallium-containing polymer brush film as efficient supported Lewis acid catalyst in a glass microreactor

    Directory of Open Access Journals (Sweden)

    Rajesh Munirathinam

    2013-08-01

    Full Text Available Polystyrene sulfonate polymer brushes, grown on the interior of the microchannels in a microreactor, have been used for the anchoring of gallium as a Lewis acid catalyst. Initially, gallium-containing polymer brushes were grown on a flat silicon oxide surface and were characterized by FTIR, ellipsometry, and X-ray photoelectron spectroscopy (XPS. XPS revealed the presence of one gallium per 2–3 styrene sulfonate groups of the polymer brushes. The catalytic activity of the Lewis acid-functionalized brushes in a microreactor was demonstrated for the dehydration of oximes, using cinnamaldehyde oxime as a model substrate, and for the formation of oxazoles by ring closure of ortho-hydroxy oximes. The catalytic activity of the microreactor could be maintained by periodic reactivation by treatment with GaCl3.

  2. Special Issue: Design and Engineering of Microreactor and Smart-Scaled Flow Processes

    Directory of Open Access Journals (Sweden)

    Volker Hessel

    2014-12-01

    Full Text Available Reaction-oriented research in flow chemistry and microreactor has been extensively focused upon in special journal issues and books. On a process level, this resembled the “drop-in” (retrofit concept with the microreactor replacing a conventional (batch reactor. Meanwhile, with the introduction of the mobile, compact, modular container technology, the focus is more on the process side, including also providing an end-to-end vision of intensified process design. Exactly this is the focus of the current special issue “Design and Engineering of Microreactor and Smart-Scaled Flow Processes” of the journal “Processes”. This special issue comprises three review papers, five research articles and two communications. [...

  3. Proteolytic Digestion and TiO2 Phosphopeptide Enrichment Microreactor for Fast MS Identification of Proteins

    Science.gov (United States)

    Deng, Jingren; Lazar, Iulia M.

    2016-04-01

    The characterization of phosphorylation state(s) of a protein is best accomplished by using isolated or enriched phosphoprotein samples or their corresponding phosphopeptides. The process is typically time-consuming as, often, a combination of analytical approaches must be used. To facilitate throughput in the study of phosphoproteins, a microreactor that enables a novel strategy for performing fast proteolytic digestion and selective phosphopeptide enrichment was developed. The microreactor was fabricated using 100 μm i.d. fused-silica capillaries packed with 1-2 mm beds of C18 and/or TiO2 particles. Proteolytic digestion-only, phosphopeptide enrichment-only, and sequential proteolytic digestion/phosphopeptide enrichment microreactors were developed and tested with standard protein mixtures. The protein samples were adsorbed on the C18 particles, quickly digested with a proteolytic enzyme infused over the adsorbed proteins, and further eluted onto the TiO2 microreactor for enrichment in phosphopeptides. A number of parameters were optimized to speed up the digestion and enrichments processes, including microreactor dimensions, sample concentrations, digestion time, flow rates, buffer compositions, and pH. The effective time for the steps of proteolytic digestion and enrichment was less than 5 min. For simple samples, such as standard protein mixtures, this approach provided equivalent or better results than conventional bench-top methods, in terms of both enzymatic digestion and selectivity. Analysis times and reagent costs were reduced ~10- to 15-fold. Preliminary analysis of cell extracts and recombinant proteins indicated the feasibility of integration of these microreactors in more advanced workflows amenable for handling real-world biological samples.

  4. A low perfusion rate microreactor for the continous monitoring of enzyme characteristics: applications for glucose oxidase.

    OpenAIRE

    Posthuma-Trumpie, G. A.; Venema, K.; Berkel, van, W.J.H.; Korf, J.

    2007-01-01

    This report describes a versatile and robust microreactor for bioactive proteins physically immobilized on a polyether sulfone filter. The potential of the reactor is illustrated with glucose oxidase immobilized on a filter with a cut-off value of 30 kDa. A flow-injection system was used to deliver the reactants and the device was linked on-line to an electrochemical detector. The microreactor was used for on-line preparation of apoglucose oxidase in strong acid and its subsequent reactivatio...

  5. A low perfusion rate microreactor for continuous monitoring of enzyme characteristics: application to glucose oxidase

    OpenAIRE

    Posthuma-Trumpie, G. A.; Venema, K.; Van Berkel, W.J.H.; Korf, J.

    2007-01-01

    This report describes a versatile and robust microreactor for bioactive proteins physically immobilized on a polyether sulfone filter. The potential of the reactor is illustrated with glucose oxidase immobilized on a filter with a cut-off value of 30 kDa. A flow-injection system was used to deliver the reactants and the device was linked on-line to an electrochemical detector. The microreactor was used for on-line preparation of apoglucose oxidase in strong acid and its subsequent reactivatio...

  6. Synthesis of 5-phenyltetrazole and its N-methyl Derivatives in a Microreactor

    OpenAIRE

    E. A. Popova; Abiev, R. Sh.; Lappalainen, L. A.; Svetlov, S. D.; Andreeva, T. V.; Trifonov, R. E.; Ostrovskii, V. A.

    2014-01-01

    Azidation of benzonitrile with dimethylammonium azide yielding 5-phenyltetrazole dimethylammonium salt was performed under microreactor conditions. The kinetics of azidation of benzonitrile in DMF was investigated at the range 80–95 °С. The reaction rate constants were determined:kII·104(L mol–1 s–1): 0.79, 0.97, 1.19, 1.51, at 80, 85, 90, and 95 °С, respectively. It was found that the reaction rate constants obtained in a microreactor are comparable to ones for a batch-type reactor. The ther...

  7. A high efficiency microreactor with Pt/ZnO nanorod arrays on the inner wall for photodegradation of phenol

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Quan [State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Materials Science and Engineering, Donghua University, Shanghai 201620 (China); Zhang, Qinghong [Engineering Research Center of Advanced Glasses Manufacturing Technology, College of Materials Science and Engineering, Donghua University, Shanghai 201620 (China); Wang, Hongzhi, E-mail: wanghz@dhu.edu.cn [State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Materials Science and Engineering, Donghua University, Shanghai 201620 (China); Li, Yaogang, E-mail: yaogang_li@dhu.edu.cn [Engineering Research Center of Advanced Glasses Manufacturing Technology, College of Materials Science and Engineering, Donghua University, Shanghai 201620 (China)

    2013-06-15

    Highlights: • A novel microreactor with Pt/ZnO nanorod arrays on the inner wall is fabricated. • The microreactor shows high efficiency for photodegradation of phenol. • The Pt/ZnO nanorod arrays display high durability during continuous recycling. • It provides a new way to immobilize catalysts on the inner wall of a microchannel. -- Abstract: A high efficiency microreactor with Pt coated ZnO (Pt/ZnO) nanorod arrays on the inner wall was successfully fabricated by pumping a Pt sol into the microchannel containing preformed ZnO nanorod arrays. Phenol was selected as a persistent organic pollutant to evaluate the photocatalytic performance of the microreactors. The microreactor which was coated by Pt sol for 5 min showed the best photocatalytic performance compared with other Pt/ZnO nanorod array-modified microreactors. The presence of Pt nanoparticles on the surfaces of ZnO nanorods promoted the separation of photoinduced electron–hole pairs and thus enhanced the photocatalytic activity. In addition, the recyclable property of the microcreator was investigated. It was found that the microreactor displayed higher durability during the continuous photocatalytic process.

  8. Study to determine the technical and economic feasibility of reclaiming chemicals used in micellar polymer and low tension surfactant flooding. Final report. [Ultrafiltration membranes and reverse osmosis membranes

    Energy Technology Data Exchange (ETDEWEB)

    Stephens, R.H.; Himmelblau, A.; Donnelly, R.G.

    1978-02-01

    Energy Resources Company has developed a technology for use with enhanced oil recovery to achieve emulsion breaking and surfactant recovery. By using ultrafiltration membranes, the Energy Resources Company process can dewater an oil-in-water type emulsion expected from enhanced oil recovery projects to the point where the emulsion can be inverted and treated using conventional emulsion-treating equipment. By using a tight ultrafiltration membrane or a reverse osmosis membrane, the Energy Resources Company process is capable of recovering chemicals such as surfactants used in micellar polymer flooding.

  9. On the Design of a Reactor for High Temperature Heat Storage by Means of Reversible Chemical Reactions

    OpenAIRE

    Schmidt, Patrick

    2011-01-01

    This work aims on the investigation of factors influencing the discharge characteristicsof a heat storage system, which is based on the reversible reaction system of Ca(OH)2and CaO. As storage, a packed bed reactor with embedded plate heat exchanger forindirect heat transfer is considered. The storage system was studied theoretically bymeans of finite element analysis of a corresponding mathematical model. Parametricstudies were carried out to determine the influence of reactor design and ope...

  10. Microreactor for a transmission electron microscope and heating element and method for the manufacture thereof

    NARCIS (Netherlands)

    Creemer, J.F.; Zandbergen, H.W.; Sarro, P.M.

    2006-01-01

    A microreactor for use in a microscope, comprising a first and second cove layer (13) , which cover layers are both at least partly transparent to an electron beam (14) of an electron microscope, and extend next to each other at a mutual distance from each other and between which a chamber (15) is e

  11. Rice Husk Supported Catalysts for Degradation of Chlorobenzenes in Capillary Microreactor

    Directory of Open Access Journals (Sweden)

    Abdulelah Thabet

    2015-01-01

    Full Text Available Chlorinated organic pollutants are persistent, toxic, and ubiquitously distributed environmental contaminants. These compounds are highly bioaccumulative and adversely affect the ozone layer in the atmosphere. As such, their widespread usage is a major cause of environmental and health concern. Therefore, it is important to detoxify such compounds by environment friendly methods. In this work, rice husk supported platinum (RHA-Pt and titanium (RHA-Ti catalysts were used, for the first time, to investigate the detoxification of chlorobenzenes in a glass capillary microreactor. High potential (in kV range was applied to a reaction mixture containing buffer solution in the presence of catalyst. Due to high potential, hydroxyl and hydrogen radicals were produced, and the reaction was monitored by gas chromatography-mass spectrometry. The main advantage of this capillary reactor is the in situ generation of hydrogen for the detoxification of chlorobenzene. Various experimental conditions influencing detoxification were optimized. Reaction performance of capillary microreactor was compared with conventional catalysis. Only 20 min is sufficient to completely detoxify chlorobenzene in capillary microreactor compared to 24 h reaction time in conventional catalytic method. The capillary microreactor is simple, easy to use, and suitable for the detoxification of a wide range of chlorinated organic pollutants.

  12. A direct and sustainable synthesis of tertiary butyl esters enabled by flow microreactors.

    Science.gov (United States)

    Degennaro, Leonardo; Maggiulli, Daniela; Carlucci, Claudia; Fanelli, Flavio; Romanazzi, Giuseppe; Luisi, Renzo

    2016-08-01

    Tertiary butyl esters find large applications in synthetic organic chemistry. A straightforward method for the direct introduction of the tert-butoxycarbonyl group into a variety of organic compounds has been developed using flow microreactor systems. The resultant flow process was more efficient, versatile and sustainable compared to the batch. PMID:27383138

  13. A low perfusion rate microreactor for the continous monitoring of enzyme characteristics: applications for glucose oxidase.

    NARCIS (Netherlands)

    Posthuma-Trumpie, G.A.; Venema, K.; Berkel, van W.J.H.; Korf, J.

    2007-01-01

    This report describes a versatile and robust microreactor for bioactive proteins physically immobilized on a polyether sulfone filter. The potential of the reactor is illustrated with glucose oxidase immobilized on a filter with a cut-off value of 30 kDa. A flow-injection system was used to deliver

  14. Piperazine-containing polymer brush layer as supported base catalyst in a glass microreactor

    NARCIS (Netherlands)

    Munirathinam, Rajesh; Huskens, Jurriaan; Verboom, Willem

    2014-01-01

    The covalent attachment of piperazine onto the inner walls of a microreactor using glycidyl methacrylate polymer brushes has been demonstrated. The piperazine-containing polymer brushes were first grown on a flat silicon oxide surface and were characterized by contact angle, Fourier transform infrar

  15. A low perfusion rate microreactor for continuous monitoring of enzyme characteristics : application to glucose oxidase

    NARCIS (Netherlands)

    Posthuma-Trumpie, G. A.; Venema, K.; van Berkel, W. J. H.; Korf, J.

    2007-01-01

    This report describes a versatile and robust microreactor for bioactive proteins physically immobilized on a polyether sulfone filter. The potential of the reactor is illustrated with glucose oxidase immobilized on a filter with a cut-off value of 30 kDa. A flow-injection system was used to deliver

  16. Synthesis of Monodisperse Chitosan Nanoparticles and in Situ Drug Loading Using Active Microreactor.

    Science.gov (United States)

    Kamat, Vivek; Marathe, Ila; Ghormade, Vandana; Bodas, Dhananjay; Paknikar, Kishore

    2015-10-21

    Chitosan nanoparticles are promising drug delivery vehicles. However, the conventional method of unregulated mixing during ionic gelation limits their application because of heterogeneity in size and physicochemical properties. Therefore, a detailed theoretical analysis of conventional and active microreactor models was simulated. This led to design and fabrication of a polydimethylsiloxane microreactor with magnetic micro needles for the synthesis of monodisperse chitosan nanoparticles. Chitosan nanoparticles synthesized conventionally, using 0.5 mg/mL chitosan, were 250 ± 27 nm with +29.8 ± 8 mV charge. Using similar parameters, the microreactor yielded small size particles (154 ± 20 nm) at optimized flow rate of 400 μL/min. Further optimization at 0.4 mg/mL chitosan concentration yielded particles (130 ± 9 nm) with higher charge (+39.8 ± 5 mV). The well-controlled microreactor-based mixing generated highly monodisperse particles with tunable properties including antifungal drug entrapment (80%), release rate, and effective activity (MIC, 1 μg/mL) against Candida. PMID:26448128

  17. Lactic Acid Extraction and Mass Transfer Characteristics in Slug Flow Capillary Microreactors

    NARCIS (Netherlands)

    Susanti,; Winkelman, Jozef G.M.; Schuur, Boelo; Heeres, Hero J.; Yue, Jun

    2016-01-01

    Capillary microreactors operated under the slug flow regime were investigated for the separation of lactic acid from the aqueous phase using liquid–liquid reactive extraction. The experiments were performed at a 1:1 flow ratio of the aqueous to organic phases in a setup consisting of an inlet Y-type

  18. Ultra resolution chemical fingerprinting of dense non-aqueous phase liquids from manufactured gas plants by reversed phase comprehensive two-dimensional gas chromatography.

    Science.gov (United States)

    McGregor, Laura A; Gauchotte-Lindsay, Caroline; Daéid, Niamh Nic; Thomas, Russell; Daly, Paddy; Kalin, Robert M

    2011-07-22

    Ultra resolution chemical fingerprinting of dense non-aqueous phase liquids (DNAPLs) from former manufactured gas plants (FMGPs) was investigated using comprehensive two-dimensional gas chromatography coupled with time of flight mass spectrometry (GC×GC TOFMS). Reversed phase GC×GC (i.e. a polar primary column coupled to a non-polar secondary column) was found to significantly improve the separation of polycyclic aromatic hydrocarbons (PAHs) and their alkylated homologues. Sample extraction and cleanup was performed simultaneously using accelerated solvent extraction (ASE), with recovery rates between 76% and 97%, allowing fast, efficient extraction with minimal solvent consumption. Principal component analysis (PCA) of the GC×GC data was performed in an attempt to differentiate between twelve DNAPLs based on their chemical composition. Correlations were discovered between DNAPL composition and historic manufacturing processes used at different FMGP sites. Traditional chemical fingerprinting methods generally follow a tiered approach with sample analysis on several different instruments. We propose ultra resolution chemical fingerprinting as a fast, accurate and precise method of obtaining more chemical information than traditional tiered approaches while using only a single analytical technique. PMID:21652041

  19. Using Quantitative Reverse Transcriptase PCR and Cell Culture Plaque Assays to Determine Resistance of Toxoplasma gondii Oocysts to Chemical Sanitizers

    Science.gov (United States)

    Toxoplasma gondii oocysts are highly resistant to many chemical sanitizers. Current methods used to determine oocyst infectivity have relied exclusively on mouse, chicken, and feline bioassays. Although considered gold standards, they only provide a qualitative assessment of oocyst infectivity. I...

  20. Manufacture and application of a microfluidic chip-based 18F microreactor

    International Nuclear Information System (INIS)

    Objective: To develop a polydimethylsiloxane (PDMS) microfluidic chip-based 18F microreactor for the preparation of 18F-labeled probes. Methods: The 18F microreactor was composed of PDMS microfluidic chip and customized glass microvessel integrating with stainless capillary tube (D 0.6 mm) as heater/cooler. PDMS chips were fabricated by silk-screen printing technology,a traditional and easily accessible process. 18F-FDG and 18F-fluoroacetate (FAC) were synthesized using the 18F microreactor. TLC was applied to measure the 18F-labeling yield and the radiochemical purity of 18F-FDG and 18F-FAC. Results: The size of PDMS chip was 40.0 mm (l)×30.0 mm (w)×6.0 mm(h) and the liquid/gas inside channel was 0.3 mm (w)×50.0 μm (h). The customized glass microvessel was about 4.0 mm (D) ×30.0 mm (h) with 200 μl of reaction volume. The capillary tube which wrapped around the microvessel functioned as a heater when electric current was provided, while as a cooler when compressed air went through. The integrated 18F microreactor with a total size of 40.0 mm (l) ×30.0 mm (w) ×15.0 mm (h) was successfully used to prepare 18F-FDG and 18F-FAC, whose radiochemical purity were both higher than 96% and 18F-labeling yield was 92.5% and 90.0% respectively in the first fluorination step. Conclusions: A PDMS microfluidic chip-based 18F microreactor is developed and successfully applied to prepare 18F-FDG and 18F-FAC. It has the dual advantages of both microfluidic chip and traditional synthesis module and features of high integration, small total size and low consumption of labeling precursor. (authors)

  1. Chemical and magnetic properties of rapidly cooled metastable ferri-ilmenite solid solutions - IV: the fine structure of self-reversed thermoremanent magnetization

    Science.gov (United States)

    Robinson, Peter; McEnroe, S. A.; Fabian, K.; Harrison, R. J.; Thomas, C. I.; Mukai, H.

    2014-03-01

    Magnetic experiments, a Monte Carlo simulation and transmission electron microscopy observations combine to confirm variable chemical phase separation during quench and annealing of metastable ferri-ilmenite compositions, caused by inhomogeneous Fe-Ti ordering and anti-ordering. Separation begins near interfaces between growing ordered and anti-ordered domains, the latter becoming progressively enriched in ilmenite component, moving the Ti-impoverished hematite component into Fe-enriched diffusion waves near the interfaces. Even when disordered regions are eliminated, Fe-enriched waves persist and enlarge on anti-phase boundaries between growing and shrinking ordered and anti-ordered domains. Magnetic results and conceptual models show that magnetic ordering with falling T initiates in the Fe-enriched wave crests. Although representing only a tiny fraction of material, identified at highest Ts on a field-cooling curve, they control the `pre-destiny' of progressive magnetization at lower T. They can provide a positive magnetic moment in a minority of ordered ferrimagnetic material, which, by exchange coupling, then creates a self-reversed negative moment in the remaining majority. Four Ts or T ranges are recognized on typical field-cooling curves: TPD is the T range of `pre-destination'; TC is the predominant Curie T where major positive magnetization increases sharply; TMAX is where magnetization reaches a positive maximum, beyond which it is outweighed by self-reversed magnetization and TZM is the T where total magnetization passes zero. Disposition of these Ts on cooling curves indicate the fine structure of self-reversed thermoremanent magnetization. These results confirm much earlier suspicions that the `x-phase' responsible for self-reversed magnetization resides in Fe-enriched phase boundaries.

  2. Chromatographic elution profile of an analyte involved in reversible chemical reaction of the type A + B AB.

    Science.gov (United States)

    Kanatyeva, A Yu

    2007-05-25

    The chromatographic peak profile of the analyte involved in a chemical reaction of the type A + B AB is considered using method of the apparent adsorption isotherm. The apparent isotherms derived are nonlinear even under assumption of Henry isotherms of individual solutes. Nonlinearity of apparent adsorption isotherm results in peak distortion. The resulted chromatographic peak profile depends on several factors such as the equilibrium constant K(mob) and Henry constants of the solutes. Simulated peak profiles of solutes involved in the chemical reaction are presented as illustration of influence of various factors. PMID:16965781

  3. A microreactor-based system for the study of fast exothermic reactions in liquid phase: characterization of the system

    OpenAIRE

    Schneider, Marie-Agnès; Maeder, Thomas; Ryser, Peter; Stoessel, Francis

    2004-01-01

    A new system combining a microreactor and a microcalorimetric chip was investigated. The small size of the microreactor channel permits maintaining isothermal conditions necessary for the kinetic characterization of highly exothermic reactions. These conditions are not easily obtained in classical calorimetric systems. The degree of mixing in the microchannel, which plays an important role for the characterization of fast reactions, was determined experimentally using an iodate–iodide s...

  4. Effect of Saliva on Measurement of Chemiluminescence by a Micro-Reactor Incorporating a Micro-Channel

    OpenAIRE

    Tsukagoshi, Kazuhiko; Fukumoto, Kazuaki; Nakajima, Riichiro; Yamashita, Kenichi; Maeda, Hideaki

    2007-01-01

    Effect of saliva on measurement of chemiluminescence was examined by a micro-reactor incorporating a micro-channel. Sodium hypochlorite and hydrogen peroxide solutions were delivered into a micro-channel developed in a micro-reactor by a syringe pump, providing a laminar flow liquid-liquid interface in the channel and leading to chemiluminescence from singlet oxygen. It was found under certain conditions including saliva that ca. 5% chemiluminescence of the total chemiluminescence was lost in...

  5. Improved Peak Capacity for Capillary Electrophoretic Separations of Enzyme Inhibitors with Activity-Based Detection Using Magnetic Bead Microreactors

    OpenAIRE

    Yan, Xiaoyan; Gilman, S. Douglass

    2010-01-01

    A technique for separating and detecting enzyme inhibitors was developed using capillary electrophoresis with an enzyme microreactor. The on-column enzyme microreactor was constructed using NdFeB magnet(s) to immobilize alkaline phosphatase-coated superparamagnetic beads (2.8 μm diameter) inside a capillary before the detection window. Enzyme inhibition assays were performed by injecting a plug of inhibitor into a capillary filled with the substrate, AttoPhos. Product generated in the enzyme ...

  6. Continuous-flow microreactor multi-step synthesis of an aminonaphthalene derivative as starting material for the preparation of novel anticancer agents

    OpenAIRE

    Tietze, Lutz F.; Liu, Deshan

    2008-01-01

    A multi-step synthesis of the aminonaphthalene derivate 1 as a key intermediate in the synthesis of the duocarmycin based prodrug 2 for a selective treatment of cancer in a microreactor is described. The conditions for the synthesis in the batch mode were adjusted for application in a microreactor and the results of both methods were compared showing that the transformations in the microreactor in most cases give similar or even better results with the advantage of a continuous...

  7. Design of a Metal Oxide-Organic Framework (MoOF) Foam Microreactor: Solar-Induced Direct Pollutant Degradation and Hydrogen Generation.

    Science.gov (United States)

    Zhu, Liangliang; Fu Tan, Chuan; Gao, Minmin; Ho, Ghim Wei

    2015-12-16

    A macroporous carbon network combined with mesoporous catalyst immobilization by a template method gives a metal-oxide-organic framework (MoOF) foam microreactor that readily soaks up pollutants and localizes solar energy in itself, leading to effective degradation of water pollutants (e.g., methyl orange (MO) and also hydrogen generation. The cleaned-up water can be removed from the microreactor simply by compression, and the microreactor used repeatedly. PMID:26501718

  8. The influence of the “cage effect” on the mechanism of reversible bimolecular multistage chemical reactions in solutions

    International Nuclear Information System (INIS)

    Manifestations of the “cage effect” at the encounters of reactants are theoretically treated by the example of multistage reactions in liquid solutions including bimolecular exchange reactions as elementary stages. It is shown that consistent consideration of quasi-stationary kinetics of multistage reactions (possible only in the framework of the encounter theory) for reactions proceeding near reactants contact can be made on the basis of the concepts of a “cage complex.” Though mathematically such a consideration is more complicated, it is more clear from the standpoint of chemical notions. It is established that the presence of the “cage effect” leads to some important effects not inherent in reactions in gases or those in solutions proceeding in the kinetic regime, such as the appearance of new transition channels of reactant transformation that cannot be caused by elementary event of chemical conversion for the given mechanism of reaction. This results in that, for example, rate constant values of multistage reaction defined by standard kinetic equations of formal chemical kinetics from experimentally measured kinetics can differ essentially from real values of these constants

  9. Dense CdS thin films on fluorine-doped tin oxide coated glass by high-rate microreactor-assisted solution deposition

    Energy Technology Data Exchange (ETDEWEB)

    Su, Yu-Wei, E-mail: suyuweiwayne@gmail.com [School of Chemical, Biological and Environmental Engineering, Oregon State University, Corvallis, OR 97330 (United States); Microproducts Breakthrough Institute and Oregon Process Innovation Center, Corvallis, Oregon 97330 (United States); Ramprasad, Sudhir [Energy Processes and Materials Division, Pacific Northwest National Laboratory, Corvallis, OR 9730 (United States); Microproducts Breakthrough Institute and Oregon Process Innovation Center, Corvallis, Oregon 97330 (United States); Han, Seung-Yeol; Wang, Wei [School of Chemical, Biological and Environmental Engineering, Oregon State University, Corvallis, OR 97330 (United States); Microproducts Breakthrough Institute and Oregon Process Innovation Center, Corvallis, Oregon 97330 (United States); Ryu, Si-Ok [School of Display and Chemical Engineering, Yeungnam University, 214-1 Dae-dong, Gyeonsan, Gyeongbuk 712-749 (Korea, Republic of); Palo, Daniel R. [Barr Engineering Co., Hibbing, MN 55747 (United States); Paul, Brian K. [School of Mechanical, Industrial and Manufacturing Engineering, Oregon State University, Corvallis, OR 97330 (United States); Microproducts Breakthrough Institute and Oregon Process Innovation Center, Corvallis, Oregon 97330 (United States); Chang, Chih-hung [School of Chemical, Biological and Environmental Engineering, Oregon State University, Corvallis, OR 97330 (United States); Microproducts Breakthrough Institute and Oregon Process Innovation Center, Corvallis, Oregon 97330 (United States)

    2013-04-01

    Continuous microreactor-assisted solution deposition is demonstrated for the deposition of CdS thin films on fluorine-doped tin oxide (FTO) coated glass. The continuous flow system consists of a microscale T-junction micromixer with the co-axial water circulation heat exchanger to control the reacting chemical flux and optimize the heterogeneous surface reaction. Dense, high quality nanocrystallite CdS thin films were deposited at an average rate of 25.2 nm/min, which is significantly higher than the reported growth rate from typical batch chemical bath deposition process. Focused-ion-beam was used for transmission electron microscopy specimen preparation to characterize the interfacial microstructure of CdS and FTO layers. The band gap was determined at 2.44 eV by UV–vis absorption spectroscopy. X-ray photon spectroscopy shows the binding energies of Cd 3d{sub 3/2}, Cd 3d{sub 5/2}, S 2P{sub 3/2} and S 2P{sub 1/2} at 411.7 eV, 404.8 eV, 162.1 eV and 163.4 eV, respectively. - Highlights: ► CdS films deposited using continuous microreactor-assisted solution deposition (MASD) ► Dense nanocrystallite CdS films can be reached at a rate of 25.2 [nm/min]. ► MASD can approach higher film growth rate than conventional chemical bath deposition.

  10. Diffusion-weighted imaging of the liver at 3 T using section-selection gradient reversal: emphasis on chemical shift artefacts and lesion conspicuity

    International Nuclear Information System (INIS)

    Aim: To assess the value of section-selection gradient reversal (SSGR) in liver diffusion-weighted imaging (DWI) by comparing it to conventional DWI with an emphasis on chemical shift artefacts and lesion conspicuity. Materials and methods: Forty-eight patients (29 men and 19 women; age range 33–80 years) with 48 liver lesions underwent two DWI examinations using spectral presaturation with inversion recovery fat suppression with and without SSGR at 3 T. Two reviewers evaluated each DWI (b = 100 and b = 800 image) with respect to chemical shift artefacts and liver lesion conspicuity using five-point scales and performed pairwise comparisons between the two DWIs. The signal-to-noise ratio (SNR) of the liver and the lesion and the lesion–liver contrast-to-noise ratio (CNR) were also calculated. Results: SSGR-DWI was significantly better than conventional DWI with respect to chemical shift artefacts and lesion conspicuity in both separate reviews and pairwise comparisons (p < 0.05). There were significant differences in the SNR of the liver (b = 100 and b = 800 images) and lesion (b = 800) between SSGR-DWI and conventional DWI (p < 0.05). Conclusion: Applying the SSGR method to DWI using SPIR fat suppression at 3 T could significantly reduce chemical shift artefacts without incurring additional acquisition time or SNR penalties, which leads to increased conspicuity of focal liver lesions. - Highlights: • Chemical shift artefact in liver DWI is markedly decreased by applying SSGR. • Liver lesion conspicuity is improved by applying SSGR to DWI. • In SNR of the liver, SSGR-DWI is better than conventional DWI

  11. Fine-tuning of catalytic tin nanoparticles by the reverse micelle method for direct deposition of silicon nanowires by a plasma-enhanced chemical vapour technique.

    Science.gov (United States)

    Poinern, Gérrard E J; Ng, Yan-Jing; Fawcett, Derek

    2010-12-15

    The reverse micelle method was used for the reduction of a tin (Sn) salt solution to produce metallic Sn nanoparticles ranging from 85 nm to 140 nm in diameter. The reverse micellar system used in this process was hexane-butanol-cetyl trimethylammonium bromide (CTAB). The diameters of the Sn nanoparticles were proportional to the concentration of the aqueous Sn salt solution. Thus, the size of the Sn nanoparticles can easily be controlled, enabling a simple, reproducible mechanism for the growth of silicon nanowires (SiNWs) using plasma-enhanced chemical vapour deposition (PECVD). Both the Sn nanoparticles and silicon nanowires were characterised using field-emission scanning electron microscopy (FE-SEM). Further characterisations of the SiNW's were made using transmission electron microscopy (TEM), atomic force microscopy (AFM) and Raman spectroscopy. In addition, dynamic light scattering (DLS) was used to investigate particle size distributions. This procedure demonstrates an economical route for manufacturing reproducible silicon nanowires using fine-tuned Sn nanoparticles for possible solar cell applications. PMID:20887996

  12. Accelerated gas-liquid visible light photoredox catalysis with continuous-flow photochemical microreactors.

    Science.gov (United States)

    Straathof, Natan J W; Su, Yuanhai; Hessel, Volker; Noël, Timothy

    2016-01-01

    In this protocol, we describe the construction and use of an operationally simple photochemical microreactor for gas-liquid photoredox catalysis using visible light. The general procedure includes details on how to set up the microreactor appropriately with inlets for gaseous reagents and organic starting materials, and it includes examples of how to use it to achieve continuous-flow preparation of disulfides or trifluoromethylated heterocycles and thiols. The reported photomicroreactors are modular, inexpensive and can be prepared rapidly from commercially available parts within 1 h even by nonspecialists. Interestingly, typical reaction times of gas-liquid visible light photocatalytic reactions performed in microflow are lower (in the minute range) than comparable reactions performed as a batch process (in the hour range). This can be attributed to the improved irradiation efficiency of the reaction mixture and the enhanced gas-liquid mass transfer in the segmented gas-liquid flow regime. PMID:26633128

  13. Development of automatic combinatorial system for synthesis of nanoparticles using microreactors

    Energy Technology Data Exchange (ETDEWEB)

    Watanabe, Kosuke; Maeda, Hideaki [Interdisciplinary Graduate School of Engineering Sciences, Kyushu University, 6-1 Kasuga-koen, Kasuga, Fukuoka, 816-8580 (Japan); Orimoto, Yuuichi; Yamashita, Kenichi; Uehara, Masato; Nakamura, Hiroyuki [Measurement Solution Research Center, National Institute of Advanced Industrial Science and Technology (AIST), 807-1, Shuku, Tosu, Saga, 841-0052 (Japan); Furuya, Takeshi, E-mail: maeda-h@aist.go.jp [Nanosystem Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki, 305-8565 (Japan)

    2011-10-29

    In this study, automatic system for combinatorial synthesis of nanoparticles (NPs) was developed and optimization of reaction parameter for NPs synthesis was performed. Microreactor was employed for kinetic control constantly. Programmable equipments were employed for additional speed up and used a microreactor. Six reaction condition parameters were systematically combined to produce CdSe synthesis condition sets. Reaction conditions of 3404 experimental sets were synthesized and characterized in 1 month. As a result of some multivariate analyses using the numerous and complicated data, we found as follows: 1) neural network is an effective method to analyze data from combinatorial synthesis, 2) weighting evaluation method was effective to find the condition for balanced NP properties.

  14. Development of automatic combinatorial system for synthesis of nanoparticles using microreactors

    Science.gov (United States)

    Watanabe, Kosuke; Orimoto, Yuuichi; Yamashita, Kenichi; Uehara, Masato; Nakamura, Hiroyuki; Furuya, Takeshi; Maeda, Hideaki

    2011-10-01

    In this study, automatic system for combinatorial synthesis of nanoparticles (NPs) was developed and optimization of reaction parameter for NPs synthesis was performed. Microreactor was employed for kinetic control constantly. Programmable equipments were employed for additional speed up and used a microreactor. Six reaction condition parameters were systematically combined to produce CdSe synthesis condition sets. Reaction conditions of 3404 experimental sets were synthesized and characterized in 1 month. As a result of some multivariate analyses using the numerous and complicated data, we found as follows: 1) neural network is an effective method to analyze data from combinatorial synthesis, 2) weighting evaluation method was effective to find the condition for balanced NP properties.

  15. Lithographically fabricated silicon microreactor for in situ characterization of heterogeneous catalysts—Enabling correlative characterization techniques

    Energy Technology Data Exchange (ETDEWEB)

    Baier, S.; Rochet, A.; Hofmann, G. [Institute for Chemical Technology and Polymer Chemistry, Karlsruhe Institute of Technology, D-76131 Karlsruhe (Germany); Kraut, M. [Institute for Micro Process Engineering, Karlsruhe Institute of Technology, D-76344 Eggenstein-Leopoldshafen (Germany); Grunwaldt, J.-D., E-mail: grunwaldt@kit.edu [Institute for Chemical Technology and Polymer Chemistry, Karlsruhe Institute of Technology, D-76131 Karlsruhe (Germany); Institute of Catalysis Research and Technology, Karlsruhe Institute of Technology, D-76344 Eggenstein-Leopoldshafen (Germany)

    2015-06-15

    We report on a new modular setup on a silicon-based microreactor designed for correlative spectroscopic, scattering, and analytic on-line gas investigations for in situ studies of heterogeneous catalysts. The silicon microreactor allows a combination of synchrotron radiation based techniques (e.g., X-ray diffraction and X-ray absorption spectroscopy) as well as infrared thermography and Raman spectroscopy. Catalytic performance can be determined simultaneously by on-line product analysis using mass spectrometry. We present the design of the reactor, the experimental setup, and as a first example for an in situ study, the catalytic partial oxidation of methane showing the applicability of this reactor for in situ studies.

  16. A biphasic oxidation of alcohols to aldehydes and ketones using a simplified packed-bed microreactor

    Directory of Open Access Journals (Sweden)

    Andrew Bogdan

    2009-04-01

    Full Text Available We demonstrate the preparation and characterization of a simplified packed-bed microreactor using an immobilized TEMPO catalyst shown to oxidize primary and secondary alcohols via the biphasic Anelli-Montanari protocol. Oxidations occurred in high yields with great stability over time. We observed that plugs of aqueous oxidant and organic alcohol entered the reactor as plugs but merged into an emulsion on the packed-bed. The emulsion coalesced into larger plugs upon exiting the reactor, leaving the organic product separate from the aqueous by-products. Furthermore, the microreactor oxidized a wide range of alcohols and remained active in excess of 100 trials without showing any loss of catalytic activity.

  17. Lithographically fabricated silicon microreactor for in situ characterization of heterogeneous catalysts—Enabling correlative characterization techniques

    Science.gov (United States)

    Baier, S.; Rochet, A.; Hofmann, G.; Kraut, M.; Grunwaldt, J.-D.

    2015-06-01

    We report on a new modular setup on a silicon-based microreactor designed for correlative spectroscopic, scattering, and analytic on-line gas investigations for in situ studies of heterogeneous catalysts. The silicon microreactor allows a combination of synchrotron radiation based techniques (e.g., X-ray diffraction and X-ray absorption spectroscopy) as well as infrared thermography and Raman spectroscopy. Catalytic performance can be determined simultaneously by on-line product analysis using mass spectrometry. We present the design of the reactor, the experimental setup, and as a first example for an in situ study, the catalytic partial oxidation of methane showing the applicability of this reactor for in situ studies.

  18. Online analysis of oxygen inside silicon-glass microreactors with integrated optical sensors

    DEFF Research Database (Denmark)

    Ehgartner, Josef; Sulzer, Philipp; Burger, Tobias;

    2016-01-01

    A powerful online analysis set-up for oxygen measurements within microfluidic devices is presented. It features integration of optical oxygen sensors into microreactors, which enables contactless, accurate and inexpensive readout using commercially available oxygen meters via luminescent lifetime...... measurements in the frequency domain (phase shifts). The fabrication and patterning of sensor layers down to a size of 100 μm in diameter is performed via automated airbrush spraying and was used for the integration into silicon-glass microreactors. A novel and easily processable sensor material is also...... presented and consists of a polystyrene- silicone rubber composite matrix with embedded palladium(II) or platinum(II) meso-tetra(4-fluorophenyl) tetrabenzoporphyrin (PdTPTBPF and PtTPTBPF) as oxygen sensitive dye. The resulting sensor layers have several advantages such as being excitable with red light...

  19. Hydrogenation of Aliphatic Alkenes in a High-Temperature High-Pressure Packed-Bed Microreactor

    OpenAIRE

    Stavárek, Petr

    2012-01-01

    This contribution presents results of the characterization of a new high-temperature high-pressure integrated packed-bed microreactor (MCTU 600 from Ehrfeld Mikrotechnik BTS GmbH) for lab-scale catalyst testing. As the model reaction we used the hydrogenation of C4-C5 aliphatic alkenes heterogeneously catalyzed by Pt/Al2O3 or Pd/Al2O3.

  20. Fabrication of tunable microreactor with enzyme modified magnetic nanoparticles for microfluidic electrochemical detection of glucose

    Energy Technology Data Exchange (ETDEWEB)

    Sheng Jin; Zhang Lei; Lei Jianping [State Key Laboratory of Analytical Chemistry for Life Science, Department of Chemistry, Nanjing University, Nanjing 210093 (China); Ju Huangxian, E-mail: hxju@nju.edu.cn [State Key Laboratory of Analytical Chemistry for Life Science, Department of Chemistry, Nanjing University, Nanjing 210093 (China)

    2012-01-04

    Highlights: Black-Right-Pointing-Pointer An enzyme microreactor is prepared using an enzyme-nanoparticles packed microchannel. Black-Right-Pointing-Pointer The optimal performance can be obtained by the tunable length of the microreactor. Black-Right-Pointing-Pointer Baseline separation from interferents can be achieved with a microfluidic device. Black-Right-Pointing-Pointer A pretreatment-free determination method for glucose is proposed. - Abstract: A microfluidic device was designed for amperometric determination of glucose by packing enzyme modified magnetic nanoparticles (MNPs) in its microchannel as an enzyme microreactor. Glucose oxidase was covalently attached to the surface of MNPs and localized in the microchannel by the help of an external magnetic field, leading to a tunable packing length. By changing the length of microreactor from 3 to 10 mm, the performance for glucose detection was optimized. The optimal linear range to glucose was from 25 {mu}M to 15 mM with a detection limit of 11 {mu}M at a length of 6 mm. The inter- and intra-day precisions for determination of 1.0 mM glucose were 0.8% and 1.7%, respectively, and the device-to-device reproducibility was 95.6%. The enzyme reactor remained its 81% activity after three-week storage. Due to the advantages of the device and fracture sampling technique, serum samples could be directly sampled through the fracture to achieve baseline separation from ascorbic acid, and proteins in the samples did not interfere with the detection. This work provided a promising way for pretreatment-free determination of glucose with low cost and excellent performance.

  1. Gallium-containing polymer brush film as efficient supported Lewis acid catalyst in a glass microreactor

    OpenAIRE

    Rajesh Munirathinam; Roberto Ricciardi; Egberink, Richard J.M.; Jurriaan Huskens; Michael Holtkamp; Herbert Wormeester; Uwe Karst; Willem Verboom

    2013-01-01

    Polystyrene sulfonate polymer brushes, grown on the interior of the microchannels in a microreactor, have been used for the anchoring of gallium as a Lewis acid catalyst. Initially, gallium-containing polymer brushes were grown on a flat silicon oxide surface and were characterized by FTIR, ellipsometry, and X-ray photoelectron spectroscopy (XPS). XPS revealed the presence of one gallium per 2–3 styrene sulfonate groups of the polymer brushes. The catalytic activity of the Lewis acid-function...

  2. Development of tailored hydrogels using RAFT polymerization in continuous flow microreactor

    OpenAIRE

    Machado, Carla; Oliveira, Tânia; Reitor, Patrícia; de Oliveira, Daniela; Freitas, Filipa; Kadhirvel, Porkodi; Dias, Rolando; Costa, Mário

    2014-01-01

    This research is devoted to the development of tools aiding the production of smart hydrogels with tailored molecular architecture and properties. Molecular imprinting, RAFT polymerization and operation in continuous flow microreactor are individually considered and also simultaneously combined in order to try the synthesis of materials with improved performance. FCT and FEDER under Programme COMPETE (Project PEst-C/EQB/LA0020/2013), QREN, ON2 and FEDER (Project NORTE-07-0162-FEDER-000050)...

  3. A biphasic oxidation of alcohols to aldehydes and ketones using a simplified packed-bed microreactor

    OpenAIRE

    Andrew Bogdan; D. Tyler McQuade

    2009-01-01

    We demonstrate the preparation and characterization of a simplified packed-bed microreactor using an immobilized TEMPO catalyst shown to oxidize primary and secondary alcohols via the biphasic Anelli-Montanari protocol. Oxidations occurred in high yields with great stability over time. We observed that plugs of aqueous oxidant and organic alcohol entered the reactor as plugs but merged into an emulsion on the packed-bed. The emulsion coalesced into larger plugs upon exiting the reactor, leavi...

  4. Mass transfer during catalytic reaction in electroosmotically driven flow in a channel microreactor

    Science.gov (United States)

    Sharma, Himanshu; Vasu, Nadapana; de, Sirshendu

    2011-05-01

    Analytical solution for concentration profile in a microreactor is obtained during heterogeneous catalytic reaction. Reaction occurs in rectangular microchannel with catalyst-coated walls. Flow is induced electroosmotically in the microchannel. A general solution is obtained for first order reaction using a power series solution. Profiles of conversion, cup-mixing concentration of reactant, etc. and variation of Sherwood number is analyzed as function of operating variables. Analytical solution is compared with numerical results.

  5. Synthesis of CuInSe{sub 2} nanocrystals using a continuous hot-injection microreactor

    Energy Technology Data Exchange (ETDEWEB)

    Jin, Hyung Dae; Chang, Chih-Hung, E-mail: chih-hung.chang@oregonstate.edu [Oregon State University, School of Chemical, Biological and Environmental Engineering (United States)

    2012-10-15

    A very rapid and simple synthesis of CuInSe{sub 2} nanocrystals (NCs) was successfully performed using a continuous hot-injection microreactor with a high throughput per reactor volume. It was found that copper-rich CuInSe{sub 2} with a sphalerite structure was formed initially followed by the formation of more ordered CuInSe{sub 2} at longer reaction times along with the formation of Cu{sub 2}Se and In{sub 2}Se{sub 3}. Binary syntheses were performed and the results show a much faster formation rate of Cu{sub 2}Se than In{sub 2}Se{sub 3}. The rate limiting step in the formation of CuInSe{sub 2} is forming the In{sub 2}Se{sub 3} intermediate. Rapid synthesis of stoichiometric CuInSe{sub 2} NCs using a continuous-flow microreactor was accomplished by properly adjusting the Cu/In precursor ratio. Tuning the ratio of coordinating solvents can cause size differences from 2.6 to 4.1 nm, bandgaps from 1.1 to 1.3 eV, and different production yields of NCs. The highest production yield as determined by weight was achieved up to 660 mg/h using a microreactor with a small volume of 3.2 cm{sup 3}.

  6. Secondary-ion mass spectrometry (SIMS) analysis of catalyst coatings used in microreactors

    International Nuclear Information System (INIS)

    Secondary-ion mass spectrometry (SIMS) was used for the characterization of the catalytically active parts of a microreactor, both before and after being used in the reactor. The catalyst coatings for the microreactor were prepared in a standard way: nanoporous washcoats were deposited on the microstructures by a particle route and the active components were applied by wet impregnation using aqueous solutions of metal nitrates. On two specific catalyst systems employed for methanol steam reforming (CuO/Cr2O3/γ-Al2O3 and CuO/CeO2/γ-Al2O3) the distributions of the relevant elements in these films were analyzed, both in depth and laterally, by SIMS. Depth profiling demonstrates a rather homogeneous distribution of the active components throughout the Al2O3 layers, whereas some inhomogeneities were observed in lateral elemental mappings. The compositional modifications induced in these films by their use in the microreactor will also be discussed

  7. A biofilm microreactor system for simultaneous electrochemical and nuclear magnetic resonance techniques

    Energy Technology Data Exchange (ETDEWEB)

    Renslow, Ryan S.; Babauta, Jerome T.; Majors, Paul D.; Mehta, Hardeep S.; Ewing, R James; Ewing, Thomas; Mueller, Karl T.; Beyenal, Haluk

    2014-03-01

    In order to fully understand electrochemically active biofilms and the limitations to their scale-up in industrial biofilm reactors, a complete picture of the microenvironments inside the biofilm is needed. Nuclear magnetic resonance (NMR) techniques are ideally suited for the study of biofilms and for probing their microenvironments because these techniques allow for non-invasive interrogation and in situ monitoring with high resolution. By combining NMR with simultaneous electrochemical techniques, it is possible to sustain and study live electrochemically active biofilms. Here, we introduce a novel biofilm microreactor system that allows for simultaneous electrochemical and NMR techniques (EC-NMR) at the microscale. Microreactors were designed with custom radiofrequency resonator coils, which allowed for NMR measurements of biofilms growing on polarized gold electrodes. For an example application of this system, we grew Geobacter sulfurreducens biofilms. NMR was used to investigate growth media flow velocities, which were compared to simulated laminar flow, and electron donor concentrations inside the biofilms. We use Monte Carlo error analysis to estimate standard deviations of the electron donor concentration measurements within the biofilm. The EC-NMR biofilm microreactor system can ultimately be used to correlate extracellular electron transfer rates with metabolic reactions and explore extracellular electron transfer mechanisms.

  8. A biofilm microreactor system for simultaneous electrochemical and nuclear magnetic resonance techniques

    International Nuclear Information System (INIS)

    In order to fully understand electrochemically active biofilms and the limitations to their scale-up in industrial biofilm reactors, a complete picture of the microenvironments inside the biofilm is needed. Nuclear magnetic resonance (NMR) techniques are ideally suited for the study of biofilms and for probing their microenvironments because these techniques allow for non-invasive interrogation and in situ monitoring with high resolution. By combining NMR with simultaneous electrochemical techniques, it is possible to sustain and study live electrochemically active biofilms. Here, we introduce a novel biofilm microreactor system that allows for simultaneous electrochemical and NMR techniques (EC-NMR) at the microscale. Microreactors were designed with custom radiofrequency resonator coils, which allowed for NMR measurements of biofilms growing on polarized gold electrodes. For an example application of this system, we grew Geobacter sulfurreducens biofilms. NMR was used to investigate growth media flow velocities, which were compared to simulated laminar flow, and electron donor concentrations inside the biofilms. We use Monte Carlo error analysis to estimate standard deviations of the electron donor concentration measurements within the biofilm. The EC-NMR biofilm microreactor system can ultimately be used to correlate extracellular electron transfer rates with metabolic reactions and explore extracellular electron transfer mechanisms

  9. Aldol addition of dihydroxyacetone to N-Cbz-3-aminopropanal catalyzed by two aldolases variants in microreactors.

    Science.gov (United States)

    Sudar, Martina; Findrik, Zvjezdana; Vasić-Rački, Durđa; Clapés, Pere; Lozano, Carles

    2013-06-10

    Aldol addition of dihydroxyacetone to N-Cbz-3-aminopropanal catalyzed by two d-fructose-6-phosphate aldolase variants, FSA A129S and FSA A129S/A165G, overexpressed in Escherichia coli was studied in microreactors. The presence of organic solvent was necessary due to poor solubility of N-Cbz-3-aminopropanal in water. Hence, three co-solvents were evaluated: ethyl acetate, acetonitrile and dimethylformamide (DMF). The influence of these solvents and their concentration on the enzyme activity was independently tested and it was found that all solvents significantly reduce the activity of FSA depending on their concentration. The reaction was carried out in three different microreactors; two without and one with micromixers. By increasing enzyme concentration, it was possible to achieve higher substrate conversion at lower residence time. Enzyme activity measured at the outlet flow of the microreactor at different residence time revealed that enzymes are more stable at lower residence times due to shorter time of exposure to organic solvent. The reaction in the batch reactor was compared with the results in microreactor with micromixers. Volume productivity was more than three fold higher in microreactor with micromixers than in the batch reactor for both aldolases. It was found to be 0.88Md(-1) and 0.80Md(-1) for FSA A129S and FSA A129S/A165G, respectively. PMID:23683703

  10. Qualitative Aspects of the Solutions of a Mathematical Model for the Dynamic Analysis of the Reversible Chemical Reaction SO2(g)+1/2O2(g)<=>SO3(g) in a Catalytic Reactor

    CERN Document Server

    Wilfredo, Angulo

    2014-01-01

    We present some qualitative aspects concerning the solution to the mathematical model describing the dynamical behavior of the reversible chemical reaction SO2(g)+1/2O2(g)SO3(g) carried out in a catalytic reactor used in the process of sulfuric acid production.

  11. A PORTABLE MICROREACTOR SYSTEM TO SYNTHESIZE HYDROGEN PEROXIDE - PHASE I

    Science.gov (United States)

    In the event that vehicles of buildings become contaminated by hazardous chemical or biological materials, a well-studied and effective decontaminant is hydrogen peroxide vapor (HPV).  Unfortunately, the current technology for generating HPV requires 35 weight percent hydro...

  12. Electrochemical Microreactor Design for Alkoxylation Reactions—Experiments and Simulations

    Czech Academy of Sciences Publication Activity Database

    Křišťál, Jiří; Kodým, R.; Bouzek, K.; Jiřičný, Vladimír; Hanika, Jiří

    2012-01-01

    Roč. 51, č. 4 (2012), s. 1515-1524. ISSN 0888-5885 R&D Projects: GA ČR GA104/09/0880 Institutional research plan: CEZ:AV0Z40720504 Keywords : interdigitated band electrodes * high-conversion reactor * water electrolysis Subject RIV: CI - Industrial Chemistry, Chemical Engineering Impact factor: 2.206, year: 2012

  13. Reversible control of magnetism in La0.67Sr0.33MnO3 through chemically-induced oxygen migration

    Science.gov (United States)

    Grutter, A. J.; Gilbert, D. A.; Alaan, U. S.; Arenholz, E.; Maranville, B. B.; Borchers, J. A.; Suzuki, Y.; Liu, Kai; Kirby, B. J.

    2016-02-01

    We demonstrate reversible control of magnetization and anisotropy in La0.67Sr0.33MnO3 films through interfacial oxygen migration. Gd metal capping layers deposited onto La0.67Sr0.33MnO3 leach oxygen from the film through a solid-state redox reaction to form porous Gd2O3. X-ray absorption and polarized neutron reflectometry measurements show Mn valence alterations consistent with high oxygen vacancy concentrations, resulting in suppressed magnetization and increased coercive fields. Effects of the oxygen migration are observed both at the interface and also throughout the majority of a 40 nm thick film, suggesting extensive diffusion of oxygen vacancies. After Gd-capped La0.67Sr0.33MnO3 is exposed to atmospheric oxygen for a prolonged period of time, oxygen diffuses through the Gd2O3 layer and the magnetization of the La0.67Sr0.33MnO3 returns to the uncapped value. These findings showcase perovskite heterostructures as ideal candidates for developing functional interfaces through chemically-induced oxygen migration.

  14. Photoluminescence and chemical properties of ZnS:Mn2+ nanocrystal powder synthesized in the AOT reverse micelles modified with lauryl phosphate

    International Nuclear Information System (INIS)

    A transparent colloidal solution of the ZnS:Mn2+ nanocrystal was prepared in hybrid reverse micelles comprising two kinds of surfactants: sodium bis(2-ethylhexyl)sulfosuccinate (AOT) and lauryl phosphate (HLP). Then, the powdered sample was obtained from the colloidal solution by coagulation of these micelles. Modification of HLP surfactant increases the photoluminescence (PL) intensity due to the d-d transition of Mn2+ ions for both of the colloidal solution and the powder. FT-IR spectra and energy dispersive X-ray analysis (EDX) data reveal that HLP modifies ZnS:Mn2+ nanocrystals more preferentially than AOT. The detailed investigation on chemical interaction between HLP molecules and ZnS nanocrystals with and without Mn2+ is performed by solid-state nuclear magnetic resonance (NMR) techniques of 31P inversion recovery and 1H →31P cross-polarization (CP) in a magnetic field of 11.7 T using magic angle spinning (MAS) at a high spinning rate of 19 and 28 kHz, respectively. These NMR results suggest that most of HLP molecules strongly interact with nanocrystals through coordination bonds and/or hydrogen bonds

  15. CHEMICALS

    CERN Multimedia

    Medical Service

    2002-01-01

    It is reminded that all persons who use chemicals must inform CERN's Chemistry Service (TIS-GS-GC) and the CERN Medical Service (TIS-ME). Information concerning their toxicity or other hazards as well as the necessary individual and collective protection measures will be provided by these two services. Users must be in possession of a material safety data sheet (MSDS) for each chemical used. These can be obtained by one of several means : the manufacturer of the chemical (legally obliged to supply an MSDS for each chemical delivered) ; CERN's Chemistry Service of the General Safety Group of TIS ; for chemicals and gases available in the CERN Stores the MSDS has been made available via EDH either in pdf format or else via a link to the supplier's web site. Training courses in chemical safety are available for registration via HR-TD. CERN Medical Service : TIS-ME :73186 or service.medical@cern.ch Chemistry Service : TIS-GS-GC : 78546

  16. Lithographically fabricated silicon microreactor for operando QEXAFS studies in exhaust gas catalysis during simulation of a standard driving cycle

    Science.gov (United States)

    Doronkin, D. E.; Baier, S.; Sheppard, T.; Benzi, F.; Grunwaldt, J.-D.

    2016-05-01

    Selective catalytic reduction of NOx by ammonia over Cu-ZSM-5 was monitored by operando QEXAFS during simulation of the New European Driving Cycle. The required fast temperature transients were realized using a novel silicon microreactor, enabling simultaneous spectroscopic and kinetic analysis by X-ray absorption spectroscopy (XAS) and mass spectrometry (MS). Periods of high temperature were correlated to an increase in both N2 production and change of coordination of Cu sites. This operando approach using Si microreactors can be applied to other heterogeneous catalytic systems involving fast temperature transients.

  17. High mass resolution time of flight mass spectrometer for measuring products in heterogeneous catalysis in highly sensitive microreactors

    DEFF Research Database (Denmark)

    Andersen, Thomas; Jensen, Robert; Christensen, M. K.;

    2012-01-01

    We demonstrate a combined microreactor and time of flight system for testing and characterization of heterogeneous catalysts with high resolution mass spectrometry and high sensitivity. Catalyst testing is performed in silicon-based microreactors which have high sensitivity and fast thermal...... response. Gas analysis is performed with a time of flight mass spectrometer with a modified nude Bayard-Alpert ionization gauge as gas ionization source. The mass resolution of the time of flight mass spectrometer using the ion gauge as ionization source is estimated to m∕Δm > 2500. The system design...

  18. On-chip enzymatic microreactor using trypsin-immobilized superparamagnetic nanoparticles for highly efficient proteolysis.

    Science.gov (United States)

    Liu, Junyan; Lin, Shuang; Qi, Dawei; Deng, Chunhui; Yang, Pengyuan; Zhang, Xiangmin

    2007-12-28

    An easily replaceable microchip enzymatic microreactor has been fabricated based on the glass microchip with trypsin-immobilized superparamagnetic nanoparticles. Magnetic nanoparticles with small size (50 nm in diameter) and strong magnetism were synthesized. At first, amine-functionalized magnetic nanoparticles with high magnetic responsivity and excellent dispersibility were prepared through a facile one-pot strategy. Then, magnetic nanoparticles were functionalized with numerous aldehyde (-CHO) groups by treating the as-synthesized, amine-functionalized magnetic nanoparticles with glutaraldehyde. Finally, immobilization of trypsin onto the aldehyde-functionalized magnetic nanoparticles was achieved through reaction of the aldehyde groups with amine groups of trypsin. The prepared magnetic nanoparticles were then locally packed onto the glass microchip by the application of a strong magnetic field using a magnet to form an on-chip magnetic nanoparticles packing bed. Capability of the proteolytic microreactor was demonstrated by cytochrome c, bovine serum albumin and myoglobin as model proteins. The digestion products were characterized using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry with sequence coverage of 83%, 43% and 79% observed, respectively. Complete protein digestion was achieved in a short time (10 s) under the flow rate of 5 microL/min. These results are expected to open up a new possibility for the proteolysis analysis as well as a new application of magnetic nanoparticles. It is easy to replace the nanoparticles and make the new microreactor. It takes less than 1 min under the condition of extra magnetic to form a new packing bed. The packing bed can be used for at least five times without any treatments. Additionally, since the preparation and surface functionality of magnetic nanoparticles is low-cost and reproducible, the preparation method and application approach of the magnetic nanoparticles may find much

  19. Reverse Engineering

    International Nuclear Information System (INIS)

    This book gives descriptions of reverse engineering with principle and structure of it, including what reverse engineering is, prospect and concerned laws, basic knowledge for reverse engineering like manual and back to user mode, using tool such as IDA installation, dependency walker and dump bin, network monitoring and universal extractor. It indicates analysis of malignant code, giving explanations of file virus, spy ware, an infection way of malignant code, anti debugging like Find window.

  20. Advanced micro-reactor for space and deep sea exploration: a scientific Brazilian vision

    International Nuclear Information System (INIS)

    Humankind is at the point to initiate a new adventure in its evolutionary journey, the colonization of other planets of our solar system and space travels. Also, there is still another frontier where the human presence is scarce, the oceans and the Earth seabed. To have success in the exploration of these new frontiers a fundamental requirement must be satisfied: secure availability of energy for life support and others processes. This work deals with the establishment of a basis for a Brazilian nuclear research and development (R and D) program to develop micro-reactor (MR) technologies that may be used in the seabed, the space or another hostile environment on Earth. The work presents a set of basic requirements that is used to define the best reactor type to be used in these environments. Also, the limits and dimensions that define the class of micro-reactors are discussed. The fast neutron spectrum was chosen as the best for the MR and the limits for the active core volume and thermal power are 30 liters and 5 MW. (author)

  1. Ultrafast synthesis of isoquercitrin by enzymatic hydrolysis of rutin in a continuous-flow microreactor

    Directory of Open Access Journals (Sweden)

    Wang Jun

    2015-01-01

    Full Text Available Isoquercitrin is a rare flavonol glycoside with a wide range of biological activities and is a key synthetic intermediate for the production of enzymatically modified isoquercitrin. In order to establish an ultrafast bioprocess for obtaining isoquercitrin, a novel continuous flow biosynthesis of isoquercitrin using the hesperidinase-catalyzed hydrolysis of rutin in a glass-polydimethylsiloxane (PDMS microreactor was first carried out. Using the developed microchannel reactor (200μm width, 50μm depth, and 2 m length with one T-shaped inlet and one outlet, the maximum yield of isoquercitrin (98.6% was achieved in a short time (40 min under the following optimum conditions: rutin concentration at 1 g L-1, hesperidinase concentration at 0.1 g mL-1, reaction temperature at 40°C, and a flow rate at 2 μL min-1. The activation energy value Ea of the enzymatic reaction was 4.61 kJ mol-1, and the reaction rate and volumetric productivity were approximately 16.1-fold and 30% higher, respectively, than those in the batch reactor. Thus, the use of a continuous-flow microreactor for the enzymatic hydrolysis of rutin is an efficient and simple approach to achieve a relative high yield of isoquercitrin.

  2. Nested potassium hydroxide etching and protective coatings for silicon-based microreactors

    Science.gov (United States)

    de Mas, Nuria; Schmidt, Martin A.; Jensen, Klavs F.

    2014-03-01

    We have developed a multilayer, multichannel silicon-based microreactor that uses elemental fluorine as a reagent and generates hydrogen fluoride as a byproduct. Nested potassium hydroxide etching (using silicon nitride and silicon oxide as masking materials) was developed to create a large number of channels (60 reaction channels connected to individual gas and liquid distributors) of significantly different depths (50-650 µm) with sloped walls (54.7° with respect to the (1 0 0) wafer surface) and precise control over their geometry. The wetted areas were coated with thermally grown silicon oxide and electron-beam evaporated nickel films to protect them from the corrosive fluorination environment. Up to four Pyrex layers were anodically bonded to three silicon layers in a total of six bonding steps to cap the microchannels and stack the reaction layers. The average pinhole density in as-evaporated films was 3 holes cm-2. Heating during anodic bonding (up to 350 °C for 4 min) did not significantly alter the film composition. Upon fluorine exposure, nickel films (160 nm thick) deposited on an adhesion layer of Cr (10 nm) over an oxidized silicon substrate (up to 500 nm thick SiO2) led to the formation of a nickel fluoride passivation layer. This microreactor was used to investigate direct fluorinations at room temperature over several hours without visible signs of film erosion.

  3. Versatile hydrogel-based nanocrystal microreactors towards uniform fluorescent photonic crystal supraballs

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Jing; Tian, Yu; Ling, Lu-Ting; Yin, Su-Na; Wang, Cai-Feng; Chen, Su, E-mail: chensu-njut@163.com, E-mail: chensu@njtech.edu.cn [Nanjing Tech University, State Key Laboratory of Materials-Oriented Chemical Engineering, College of Chemistry and Chemical Engineering (China)

    2014-12-15

    Versatile hydrogel-based nanocrystal (NC) microreactors were designed in this work for the construction of uniform fluorescence colloidal photonic crystal (CPC) supraballs. The hydrogel-based microspheres with sizes ranging from 150 to 300 nm were prepared by seeded copolymerization of acrylic acid and 2-hydroxyethyl methacrylate with micrometer-sized PS seed particles. As an independent NC microreactor, the as-synthesized hydrogel microsphere can effectively capture the guest cadmium ions due to the abundant carboxyl groups inside. Followed by the introduction of chalcogenides, in situ generation of higher-uptake NCs with sizes less than 5 nm was finally realized. Additionally, with the aid of the microfluidic device, the as-obtained NC–latex hybrids can be further self-assembled to bi-functional CPC supraballs bearing brilliant structural colors and uniform fluorescence. This research offers an alternative way to finely bind CPCs with NCs, which will facilitate progress in fields of self-assembled functional colloids and photonic materials.

  4. Real-time loop-mediated isothermal DNA amplification in compact disc micro-reactors.

    Science.gov (United States)

    Santiago-Felipe, Sara; Tortajada-Genaro, Luis A; Carrascosa, Javier; Puchades, Rosa; Maquieira, Ángel

    2016-05-15

    An integrated device composed of micro-reactors embedded onto compact discs is proposed for real-time targeted DNA determination. The method principle is based on in-disc loop-mediated isothermal amplification (iD-LAMP) and quantitative optical read-out by a disc drive. In the presence of a target, the turbidimetric or colorimetric properties of reaction solution change, and the transmitted intensity of the disc drive laser modifies according to reaction yield. Monitoring real-time curves allowed the quantitative determination of DNA template amounts. The best amplification/detection results were obtained with micro-reactors (2mm diameter and 1.1mm in depth) drilled on a digital video disc (DVD) and detection based on the colorimetric mode. As proof-of-concept, the assay was applied to detect pathogenic bacteria Salmonella spp. and to identify bovine meat in food samples. Ninety-six samples were simultaneously analysed in 15min, with high selectivity and sensitivity (5CFU/mL and 10µg/g for bacteria and meat, respectively). The in-disc results were comparable to those obtained by conventional LAMP or qPCR approaches. The developed device allows low sample and reagent consumption (3µL of reaction), portability, ease-of-use, and rapid low-cost high-throughput analyses. PMID:26716424

  5. Nested potassium hydroxide etching and protective coatings for silicon-based microreactors

    International Nuclear Information System (INIS)

    We have developed a multilayer, multichannel silicon-based microreactor that uses elemental fluorine as a reagent and generates hydrogen fluoride as a byproduct. Nested potassium hydroxide etching (using silicon nitride and silicon oxide as masking materials) was developed to create a large number of channels (60 reaction channels connected to individual gas and liquid distributors) of significantly different depths (50–650 µm) with sloped walls (54.7° with respect to the (1 0 0) wafer surface) and precise control over their geometry. The wetted areas were coated with thermally grown silicon oxide and electron-beam evaporated nickel films to protect them from the corrosive fluorination environment. Up to four Pyrex layers were anodically bonded to three silicon layers in a total of six bonding steps to cap the microchannels and stack the reaction layers. The average pinhole density in as-evaporated films was 3 holes cm−2. Heating during anodic bonding (up to 350 °C for 4 min) did not significantly alter the film composition. Upon fluorine exposure, nickel films (160 nm thick) deposited on an adhesion layer of Cr (10 nm) over an oxidized silicon substrate (up to 500 nm thick SiO2) led to the formation of a nickel fluoride passivation layer. This microreactor was used to investigate direct fluorinations at room temperature over several hours without visible signs of film erosion. (paper)

  6. Versatile hydrogel-based nanocrystal microreactors towards uniform fluorescent photonic crystal supraballs

    International Nuclear Information System (INIS)

    Versatile hydrogel-based nanocrystal (NC) microreactors were designed in this work for the construction of uniform fluorescence colloidal photonic crystal (CPC) supraballs. The hydrogel-based microspheres with sizes ranging from 150 to 300 nm were prepared by seeded copolymerization of acrylic acid and 2-hydroxyethyl methacrylate with micrometer-sized PS seed particles. As an independent NC microreactor, the as-synthesized hydrogel microsphere can effectively capture the guest cadmium ions due to the abundant carboxyl groups inside. Followed by the introduction of chalcogenides, in situ generation of higher-uptake NCs with sizes less than 5 nm was finally realized. Additionally, with the aid of the microfluidic device, the as-obtained NC–latex hybrids can be further self-assembled to bi-functional CPC supraballs bearing brilliant structural colors and uniform fluorescence. This research offers an alternative way to finely bind CPCs with NCs, which will facilitate progress in fields of self-assembled functional colloids and photonic materials

  7. Microfluidic characteristics of a multi-holed baffle plate micro-reactor

    International Nuclear Information System (INIS)

    As part of a larger project aiming at development of a miniaturized hydrogen generator for small mobile/onboard fuel cell applications, a series of experiments was conducted on a novel micro-reactor to examine the effectiveness of its design in promoting the mixing of reactant agents. The reactor is essentially a tubular vessel fitted with a multi-holed baffle plate mounted on a central tube. The mixing phenomenon within the micro-reactor was studied using the micro-PIV (micro-particle image velocimetry) flow visualization technique. Experiments were conducted on a 1:1 scale replica of the reactor. Results indicate that the application of the multi-holed baffle plate considerably improves the mixing performance of the reactor when compared with a simpler co-axial jet tubular reactor. However, the geometrical characteristics of the baffle plate and central tube are found to have dramatic impacts upon the flow structure and mixing patterns within the reactor. Hence, the optimization of the reactor geometry is required to achieve the desirable mixing performance. For the range of Reynolds numbers studied here, the optimum reactor geometry is achieved when the central tube and baffle holes are of similar diameters and baffle holes are located half way between the stream-wise axis and the reactor wall

  8. Modeling of methanol decomposition on Pt/CeO2/ZrO2 catalyst in a packed bed microreactor

    Science.gov (United States)

    Pohar, Andrej; Belavič, Darko; Dolanc, Gregor; Hočevar, Stanko

    2014-06-01

    Methanol decomposition on Pt/CeO2/ZrO2 catalyst is studied inside a packed bed microreactor in the temperature range of 300-380 °C. The microreactor is fabricated using low-temperature co-fired ceramic (LTCC) technology, which is well suited for the production of relatively complex three-dimensional structures. It is packed with 2 wt% Pt-CeO2 catalyst, which is deposited onto ZrO2 spherical particles. A 1D mathematical model, which incorporates diffusion, convection and mass transfer through the boundary layer to the catalyst particles, as well as a 3D computational fluid dynamics model, are developed to describe the methanol decomposition process inside the packed bed. The microreactor exhibits reliable operation and no catalyst deactivation was observed during three months of experimentation. A comparison between the 1D mathematical model and the 3D model, considering the full 3D geometry of the microreactor is made and the differences between the models are identified and evaluated.

  9. Spatially resolved in situ FTIR analysis of CO adsorption and reaction on Pt/SiO2 in a silicon microreactor

    OpenAIRE

    Tan, Christopher CK; Delgass, Nicholas W; Baertsch, Chelsey D

    2009-01-01

    The design, fabrication and testing of a microreactor-FTIR imaging system is shown and used for the first time to demonstrate the ability to obtain in situ transmission FTIR analysis of working catalysts with both spatial and temporal resolution. MEMS (MicroElectroMechanical Systems) and microfabrication technologies were used to design and fabricate a microreactor with geometric and optical properties ideal for coupling with a high-throughput transmission FPA-FTIR system. CO adsorption and o...

  10. Vasectomy Reversal

    Medline Plus

    Full Text Available ... is a realistic option for many patients. Today we are going to go to the operating room and show you microsurgical vasectomy reversal. We start the procedure by localizing the site of ...

  11. Vasectomy Reversal

    Medline Plus

    Full Text Available ... keep the vas well vascularized because ischemia will cause fibrosis and scarring and prevent the vasectomy reversal ... to make sure that we don't inadvertently cause any vascular to the vas or even to ...

  12. Vasectomy Reversal

    Medline Plus

    Full Text Available ... improving health. Hello, my name is Harris Nagler. I'm the Chairman of the Sol and Margaret ... Israel Medical Center in New York City. Today I'm going to perform a vasectomy reversal using ...

  13. Vasectomy Reversal

    Medline Plus

    Full Text Available ... Today we are going to go to the operating room and show you microsurgical vasectomy reversal. We ... vas and that will be examined under the operating- under the microscope to see if there’s sperm ...

  14. Reversible Sterilization

    Science.gov (United States)

    Largey, Gale

    1977-01-01

    Notes that difficult questions arise concerning the use of sterilization for alleged eugenic and euthenic purposes. Thus, how reversible sterilization will be used with relation to the poor, mentally ill, mentally retarded, criminals, and minors, is questioned. (Author/AM)

  15. Vasectomy Reversal

    Medline Plus

    Full Text Available Vasectomy Reversal Beth Israel Medical Center, New York, NY February 19, 2009 Welcome to this "OR Live" Webcast presentation premiering from Beth Israel Medical Center in New York City. ...

  16. Vasectomy Reversal

    Medline Plus

    Full Text Available Vasectomy Reversal Beth Israel Medical Center, New York, NY February 19, 2009 Welcome to this "OR Live" Webcast presentation premiering from Beth Israel Medical Center in New York City. During the ...

  17. Double Emulsion Droplets as Microreactors for Synthesis of Magnetic Macroporous Polymer Beads

    Institute of Scientific and Technical Information of China (English)

    Wei-cai Wang; Chao Peng; Kai Shi; Yan-xiong Pan; Hai-shan Zhang; Xiang-ling Ji

    2014-01-01

    An easy method is presented to fabricate monodisperse magnetic macroporous polymer beads (MMPBs).Waterin-oil high intemal phase emulsion (HIPE) is prepared by emulsifying aqueous iron ions solution in an oil phase containing monomers.The HIPE is introduced into a simple microfluidic device to fabricate monodisperse (water-in-oil)-in-water double emulsion droplets.The droplets serve as microreactors to synthesize Fe3O4 nanoparticles and are on-line polymerized to form MMPBs.The prepared MMPBs display uniform size,interconnected porous structure,superparamagnetic behavior and uniform distribution of Fe3O4 in polymer matrix.The MMPBs are characterized by scanning electron microscopy (SEM),Fourier transform infrared spectroscopy (FTIR),X-ray diffraction (XRD),transmission electron microscopy (TEM),vibrating sample magnetometry (VSM).We believe that this method is a universal technique in preparing macroporous nanocomposite beads.

  18. Size-controlled synthesis of ZnO quantum dots in microreactors

    Science.gov (United States)

    Schejn, Aleksandra; Frégnaux, Mathieu; Commenge, Jean-Marc; Balan, Lavinia; Falk, Laurent; Schneider, Raphaël

    2014-04-01

    In this paper, we report on a continuous-flow microreactor process to prepare ZnO quantum dots (QDs) with widely tunable particle size and photoluminescence emission wavelengths. X-ray diffraction, electron diffraction, UV-vis, photoluminescence and transmission electron microscopy measurements were used to characterize the synthesized ZnO QDs. By varying operating conditions (temperature, flow rate) or the capping ligand, ZnO QDs with diameters ranging from 3.6 to 5.2 nm and fluorescence maxima from 500 to 560 nm were prepared. Results obtained show that low reaction temperatures (20 or 35 °C), high flow rates and the use of propionic acid as a stabilizing agent are favorable for the production of ZnO QDs with high photoluminescence quantum yields (up to 30%).

  19. Microreactor and method for preparing a radiolabeled complex or a biomolecule conjugate

    Energy Technology Data Exchange (ETDEWEB)

    Reichert, David E; Kenis, Paul J. A.; Wheeler, Tobias D; Desai, Amit V; Zeng, Dexing; Onal, Birce C

    2015-03-17

    A microreactor for preparing a radiolabeled complex or a biomolecule conjugate comprises a microchannel for fluid flow, where the microchannel comprises a mixing portion comprising one or more passive mixing elements, and a reservoir for incubating a mixed fluid. The reservoir is in fluid communication with the microchannel and is disposed downstream of the mixing portion. A method of preparing a radiolabeled complex includes flowing a radiometal solution comprising a metallic radionuclide through a downstream mixing portion of a microchannel, where the downstream mixing portion includes one or more passive mixing elements, and flowing a ligand solution comprising a bifunctional chelator through the downstream mixing portion. The ligand solution and the radiometal solution are passively mixed while in the downstream mixing portion to initiate a chelation reaction between the metallic radionuclide and the bifunctional chelator. The chelation reaction is completed to form a radiolabeled complex.

  20. Gas bubble formation and its pressure signature in T-junction of a microreactor

    Science.gov (United States)

    Pouya, Shahram; Koochesfahani, Manoochehr

    2013-11-01

    The segmented gas-liquid flow is of particular interest in microreactors used for high throughput material synthesis with enhanced mixing and more efficient reaction. A typical geometry to introduce gas plugs into the reactor is a T-junction where the dispersed liquid is squeezed and pinched by the continuous fluid in the main branch of the junction. We present experimental data of time resolved pressure along with synchronous imaging of the drop formation at the junction to show the transient behavior of the process. The stability of the slug regime and the regularity of the slug/plug pattern are investigated in this study. This work was supported by the CRC Program of the National Science Foundation, Grant Number CHE-0714028.

  1. Continuous Microreactor-Assisted Solution Deposition for Scalable Production of CdS Films

    Energy Technology Data Exchange (ETDEWEB)

    Ramprasad, Sudhir; Su, Yu-Wei; Chang, Chih-Hung; Paul, Brian; Palo, Daniel R.

    2013-06-13

    Solution deposition offers an attractive, low temperature option in the cost effective production of thin film solar cells. Continuous microreactor-assisted solution deposition (MASD) was used to produce nanocrystalline cadmium sulfide (CdS) films on fluorine doped tin oxide (FTO) coated glass substrates with excellent uniformity. We report a novel liquid coating technique using a ceramic rod to efficiently and uniformly apply reactive solution to large substrates (152 mm × 152 mm). This technique represents an inexpensive approach to utilize the MASD on the substrate for uniform growth of CdS films. Nano-crystalline CdS films have been produced from liquid phase at ~90°C, with average thicknesses of 70 nm to 230 nm and with a 5 to 12% thickness variation. The CdS films produced were characterized by UV-Vis spectroscopy, transmission electron microscopy, and X-Ray diffraction to demonstrate their suitability to thin-film solar technology.

  2. Chapter 8: Pyrolysis Mechanisms of Lignin Model Compounds Using a Heated Micro-Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Robichaud, David J.; Nimlos, Mark R.; Ellison, G. Barney

    2015-10-03

    Lignin is an important component of biomass, and the decomposition of its thermal deconstruction products is important in pyrolysis and gasification. In this chapter, we investigate the unimolecular pyrolysis chemistry through the use of singly and doubly substituted benzene molecules that are model compounds representative of lignin and its primary pyrolysis products. These model compounds are decomposed in a heated micro-reactor, and the products, including radicals and unstable intermediates, are measured using photoionization mass spectrometry and matrix isolation infrared spectroscopy. We show that the unimolecular chemistry can yield insight into the initial decomposition of these species. At pyrolysis and gasification severities, singly substituted benzenes typically undergo bond scission and elimination reactions to form radicals. Some require radical-driven chain reactions. For doubly substituted benzenes, proximity effects of the substituents can change the reaction pathways.

  3. Measurement of acetylcholinesterase inhibition using bienzymes immobilized monolith micro-reactor with integrated electrochemical detection

    Energy Technology Data Exchange (ETDEWEB)

    He Ping; Davies, Joanna; Greenway, Gillian [Department of Chemistry, University of Hull, Hull HU6 7RX (United Kingdom); Haswell, Stephen J., E-mail: s.j.haswell@hull.ac.uk [Department of Chemistry, University of Hull, Hull HU6 7RX (United Kingdom)

    2010-02-05

    This paper reports a simple {mu}-FIA based method for the rapid evaluation of acetylcholinesterase inhibition based on bienzymes immobilized monolith micro-reactor, with integrated electrochemical detection. The monolith was prepared inside a micro-fluidic device from two precursors TMOS and MTMOS using a sol-gel method, followed by PEI polymer functionalization and subsequent enzyme immobilization via electrostatic attraction between electronegative enzymes and electropositive PEI polymers. A bienzyme system containing co-immobilized acetylcholinesterase and choline oxidase was used for the evaluation of enzyme inhibition induced by malaoxon, eserine and methomyl analytes. The proposed method, which gave a LOD of 0.5, 0.2 and 1.0 {mu}M for malaoxon, eserine and methomyl repeatedly, was found to offer several advantages over existing systems including efficient enzyme immobilization, minimal reagent consumption and rapid analysis capability.

  4. Measurement of acetylcholinesterase inhibition using bienzymes immobilized monolith micro-reactor with integrated electrochemical detection

    International Nuclear Information System (INIS)

    This paper reports a simple μ-FIA based method for the rapid evaluation of acetylcholinesterase inhibition based on bienzymes immobilized monolith micro-reactor, with integrated electrochemical detection. The monolith was prepared inside a micro-fluidic device from two precursors TMOS and MTMOS using a sol-gel method, followed by PEI polymer functionalization and subsequent enzyme immobilization via electrostatic attraction between electronegative enzymes and electropositive PEI polymers. A bienzyme system containing co-immobilized acetylcholinesterase and choline oxidase was used for the evaluation of enzyme inhibition induced by malaoxon, eserine and methomyl analytes. The proposed method, which gave a LOD of 0.5, 0.2 and 1.0 μM for malaoxon, eserine and methomyl repeatedly, was found to offer several advantages over existing systems including efficient enzyme immobilization, minimal reagent consumption and rapid analysis capability.

  5. Application of microreactors in polymerization%微反应器在聚合反应中的应用

    Institute of Scientific and Technical Information of China (English)

    宋顺刚; 顾雪萍; 王嘉骏; 冯连芳

    2012-01-01

    Due to its superior mixing and heat exchange properties,microreactor developed in polymerizations recently has showed a great potential.The aim of this review is to summarize the applications of microreactors in free radical,ionic and stepwise polymerizations.Molecular weight and molecular weight distribution,copolymer composition and molecular structure can be better controlled in microreactors than that in traditional batch reactors.By employing microreactors,polymers with narrow molecular weight distributions can be obtained in highly exothermic polymerizations and reaction time can be drastically reduced in diffusion-controlled polymerizations.Further applications of microreactors in polymerization reactions depend on better understanding of polymerization mechanisms and microreactor characteristics,and related theoretical investigations will be of a great importance in this area.%微反应器因其良好的混合和传热性能近年来开始应用到聚合反应中,并表现出巨大潜力。本文对微反应器在自由基聚合、离子聚合和逐步聚合中的应用进行了系统综述。相比于传统的釜式反应器,微反应器可以更好地调节聚合产物分子量和分子量分布、控制共聚组成和分子结构。在强放热聚合反应中,利用微反应器可以获得窄分子量分布的聚合产物;在扩散控制的聚合反应中,利用微反应器可以大大缩短反应所需时间。微反应器在聚合反应领域中的拓展依赖于对反应机理和微反应器特点的深入理解,相关的基础研究将成为这一领域发展的关键。

  6. 煤化工反渗透浓盐水处理和回用的探讨%On the Coal Chemical iIndustry of Reverse Osmosis Concentrated Water Treatment and Reuse of

    Institute of Scientific and Technical Information of China (English)

    陈海斌

    2012-01-01

      This paper explores how to study for coal chemical reverse osmosis concentrated brine was effective for treatment and reuse of wastewater, further improve the comprehensive reuse rate, greatly reduce discharge of wastewater and waste water discharged together with the chemical oxygen demand (COD)aggregates, which for the coal chemical industry and long-term development has important sense.%  研究探讨如何针对煤化工反渗透浓盐水进行有效处理回用,进一步提高废水的综合回用率,大幅度减少废水排放量以及随废水一同排放的化学耗氧量(COD)总量,这对于煤化工行业的长远发展具有重要意义。

  7. Optimisation and analysis of microreactor designs for microfluidic gradient generation using a purpose built optical detection system for entire chip imaging.

    Science.gov (United States)

    Abdulla Yusuf, Hayat; Baldock, Sara J; Barber, Robert W; Fielden, Peter R; Goddard, Nick J; Mohr, Stephan; Treves Brown, Bernard J

    2009-07-01

    This paper presents and fully characterises a novel simplification approach for the development of microsystem based concentration gradient generators with significantly reduced microfluidic networks. Three microreactors are presented; a pair of two-inlet six-outlet (2-6) networks and a two-inlet eleven-outlet (2-11) network design. The mathematical approach has been validated experimentally using a purpose built optical detection system. The experimental results are shown to be in very good agreement with the theoretical predictions from the model. The developed networks are proven to deliver precise linear concentration gradients (R(2) = 0.9973 and 0.9991 for the (2-6) designs) and the simplified networks are shown to provide enhanced performance over conventional designs, overcoming some of the practical issues associated with traditional networks. The optical measurements were precise enough to validate the linearity in each level of the conventional (2-6) networks (R(2) ranged from 0.9999 to 0.9973) compared to R(2) = 1 for the theoretical model. CFD results show that there is an effective upper limit on the operating flow rate. The new simplified (2-11) design was able to maintain a linear outlet profile up to 0.8 microl/s per inlet (R(2) = 0.9992). The proposed approach is widely applicable for the production of linear and arbitrary concentration profiles, with the potential for high throughput applications that span a wide range of chemical and biological studies. PMID:19532963

  8. Synthesis of robust hierarchical silica monoliths by surface-mediated solution/precipitation reactions over different scales: designing capillary microreactors for environmental applications.

    Science.gov (United States)

    García-Aguilar, J; Miguel-García, I; Berenguer-Murcia, Á; Cazorla-Amorós, D

    2014-12-24

    A synthetic procedure to prepare novel materials (surface-mediated fillings) based on robust hierarchical monoliths is reported. The methodology includes the deposition of a (micro- or mesoporous) silica thin film on the support followed by growth of a porous monolithic SiO2 structure. It has been demonstrated that this synthesis is viable for supports of different chemical nature with different inner diameters without shrinkage of the silica filling. The formation mechanism of the surface-mediated fillings is based on a solution/precipitation process and the anchoring of the silica filling to the deposited thin film. The interaction between the two SiO2 structures (monolith and thin film) depends on the porosity of the thin film and yields composite materials with different mechanical stability. By this procedure, capillary microreactors have been prepared and have been proved to be highly active and selective in the total and preferential oxidation of carbon monoxide (TOxCO and PrOxCO). PMID:25419612

  9. Tubular Structures Self-Assembled from a Bola-Amphiphilic Pillar[5]arene in Water and Applied as a Microreactor.

    Science.gov (United States)

    Chen, Rener; Jiang, Huajiang; Gu, Haining; Zhou, Qizhong; Zhang, Zhen; Wu, Jiashou; Jin, Zhengneng

    2015-09-01

    Various nanomorphologies were obtained by simply changing the fabrication conditions, such as the pH of the system, different solvent, or different concentration, of bola-amphiphilic pillar[5]arene Bola-AP5. Importantly, hybrid microtubules as a microreactor were successfully prepared by directly reducing AuCl4(-) on the surface of Bola-AP5-based tubular structures in water. PMID:26275020

  10. Mimicking Insect Communication: Release and Detection of Pheromone, Biosynthesized by an Alcohol Acetyl Transferase Immobilized in a Microreactor

    OpenAIRE

    Lourdes Muñoz; Nikolay Dimov; Gerard Carot-Sans; Bula, Wojciech P.; Angel Guerrero; Gardeniers, Han J. G. E.

    2012-01-01

    Infochemical production, release and detection of (Z,E)-9,11-tetradecadienyl acetate, the major component of the pheromone of the moth Spodoptera littoralis is achieved in a novel microfluidic system, designed to mimic the final step of the pheromone biosynthesis by immobilized recombinant alcohol acetyl transferase. The microfluidic system is part of an "artificial gland", i.e. a chemoemitter that comprises a microreactor connected to a microevaporator and is able to produce a...

  11. Aqueous two-phase micellar systems in an oscillatory flow micro-reactor: Study of perspectives and experimental performance

    OpenAIRE

    A. M. LOPES; Silva, Daniel Pereira da; A.A. Vicente; Pessoa Júnior, Adalberto; Teixeira, J. A.

    2011-01-01

    Aqueous two-phase micellar systems (ATPMS) are micellar surfactant solutions with physical properties that make them very efficient for the extraction/concentration of biological products. In this work the main proposal that has been discussed is the possible applicability and importance of a novel oscillatory flow micro-reactor (micro-OFR) envisaged for parallel screening and/or development of industrial bioprocesses in ATPMS. Based on the technology of oscillatory flow mixing (OFM), this ba...

  12. Oxidation of methane on nanoparticulate Au/TiO2 at low temperature: A combined microreactor and DFT study

    DEFF Research Database (Denmark)

    Walther, Guido; Jones, Glenn; Jensen, Søren;

    2009-01-01

    Herein we present results from experimental and theoretical studies concerning low temperature oxidation of CH4 over TiO2 supported Au nanoparticles. Our findings suggest that partial oxidation cannot be achieved under these conditions (1 bar, 30–250 °C). In order to understand this further, resu......-calculations investigating the thermodynamics of CH4 oxidation on a stepped Au(2 1 1) surface. Keywords: Gold; Titanium dioxide; Catalysis; Microreactor; Methane; Oxidation; Particle size...

  13. CFD simulation with detailed chemistry of steam reforming of methane for hydrogen production in an integrated micro-reactor

    Energy Technology Data Exchange (ETDEWEB)

    Zhai, Xuli; Cheng, Yinhong; Jin, Yong; Cheng, Yi [Department of Chemical Engineering, Beijing Key Laboratory of Green Chemical Reaction Engineering and Technology, Tsinghua University, Beijing 100084 (China); Ding, Shi [Department of Chemical Engineering, Beijing Key Laboratory of Green Chemical Reaction Engineering and Technology, Tsinghua University, Beijing 100084 (China); Research Institute of Petroleum Processing, SINOPEC, Beijing 100083 (China)

    2010-06-15

    micro-reactor has drawn more and more attention in recent years due to the process intensification on basic transport phenomena in micro-channels, which would often lead to the improved reactor performance. Steam reforming of methane (SRM) in micro-reactor has great potential to realize a low-cost, compact process for hydrogen production via an evident shortening of reaction time from seconds to milliseconds. This work focuses on the detailed modeling and simulation of a micro-reactor design for SRM reaction with the integration of a micro-channel for Rh-catalyzed endothermic reaction, a micro-channel for Pt-catalyzed exothermic reaction and a wall in between with Rh or Pt-catalyst coated layer. The elementary reaction kinetics for SRM process is adopted in the CFD model, while the combustion channel is described by global reaction kinetics. The model predictions were quantitatively validated by the experimental data in the literature. For the extremely fast reactions in both channels, the simulations indicated the significance of the heat conduction ability of the reactor wall as well as the interplay between the exothermic and endothermic reactions (e.g., the flow rate ratio of fuel gas to reforming gas). The characteristic width of 0.5 mm is considered to be a suitable channel size to balance the trade-off between the heat transfer behavior in micro-channels and the easy fabrication of micro-channels. (author)

  14. Quantitative determination of enzyme activity in single cells by scanning microelectrode coupled with a nitrocellulose film-covered microreactor by means of a scanning electrochemical microscope.

    Science.gov (United States)

    Zhang, Xiaoli; Sun, Fuchan; Peng, Xuewei; Jin, Wenrui

    2007-02-01

    An electrochemical method for quantitative determination of enzyme activity in single cells was developed by scanning a microelectrode (ME) over a nitrocellulose film-covered microreactor with micropores by means of a scanning electrochemical microscope (SECM). Peroxidase (PO) in neutrophils was chosen as the model system. The microreactor consisted of a microwell with a solution and a nitrocellulose film with micropores. A single cell perforated by digitonin was injected into the microwell. After the perforated cell was lysed and allowed to dry, physiological buffer saline (PBS) containing hydroquinone (H2Q) and H2O2 as substrates of the enzyme-catalyzed reaction was added in the microwell. The microwell containing the extract of the lysed cell and the enzyme substrates was covered with Parafilm to prevent evaporation. The solution in the microwell was incubated for 20 min. In this case, the released PO from the cell converted H2Q into benzoquinone (BQ). Then, the Parafilm was replaced by a nitrocellulose film with micropores to fabricate the microreactor. The microreactor was placed in an electrochemical cell containing PBS, H2Q, and H2O2. After a 10-microm-radius Au ME was inserted into the electrochemical cell and approached down to the microreactor, the ME was scanned along the central line across the microreactor by means of a SECM. The scan curve with a peak was obtained by detecting BQ that diffused out from the microreactor through the micropores on the nitrocellulose film. PO activity could be quantified on the basis of the peak current on the scan curve using a calibration curve. This method had two obvious advantages: no electrode fouling and no oxygen interference. PMID:17263362

  15. Isomerization and Fragmentation of Cyclohexanone in a Heated Micro-Reactor.

    Science.gov (United States)

    Porterfield, Jessica P; Nguyen, Thanh Lam; Baraban, Joshua H; Buckingham, Grant T; Troy, Tyler P; Kostko, Oleg; Ahmed, Musahid; Stanton, John F; Daily, John W; Ellison, G Barney

    2015-12-24

    The thermal decomposition of cyclohexanone (C6H10═O) has been studied in a set of flash-pyrolysis microreactors. Decomposition of the ketone was observed when dilute samples of C6H10═O were heated to 1200 K in a continuous flow microreactor. Pyrolysis products were detected and identified by tunable VUV photoionization mass spectroscopy and by photoionization appearance thresholds. Complementary product identification was provided by matrix infrared absorption spectroscopy. Pyrolysis pressures were roughly 100 Torr, and contact times with the microreactors were roughly 100 μs. Thermal cracking of cyclohexanone appeared to result from a variety of competing pathways, all of which open roughly simultaneously. Isomerization of cyclohexanone to the enol, cyclohexen-1-ol (C6H9OH), is followed by retro-Diels-Alder cleavage to CH2═CH2 and CH2═C(OH)-CH═CH2. Further isomerization of CH2═C(OH)-CH═CH2 to methyl vinyl ketone (CH3CO-CH═CH2, MVK) was also observed. Photoionization spectra identified both enols, C6H9OH and CH2═C(OH)-CH═CH2, and the ionization threshold of C6H9OH was measured to be 8.2 ± 0.1 eV. Coupled cluster electronic structure calculations were used to establish the energetics of MVK. The heats of formation of MVK and its enol were calculated to be ΔfH298(cis-CH3CO-CH═CH2) = -26.1 ± 0.5 kcal mol(-1) and ΔfH298(s-cis-1-CH2═C(OH)-CH═CH2) = -13.7 ± 0.5 kcal mol(-1). The reaction enthalpy ΔrxnH298(C6H10═O → CH2═CH2 + s-cis-1-CH2═C(OH)-CH═CH2) is 53 ± 1 kcal mol(-1) and ΔrxnH298(C6H10═O → CH2═CH2 + cis-CH3CO-CH═CH2) is 41 ± 1 kcal mol(-1). At 1200 K, the products of cyclohexanone pyrolysis were found to be C6H9OH, CH2═C(OH)-CH═CH2, MVK, CH2CHCH2, CO, CH2═C═O, CH3, CH2═C═CH2, CH2═CH-CH═CH2, CH2═CHCH2CH3, CH2═CH2, and HC≡CH. PMID:26617252

  16. Reversible dementias

    OpenAIRE

    Tripathi, Manjari; Vibha, Deepti

    2009-01-01

    In recent years, more attention has been given to the early diagnostic evaluation of patients with dementia which is essential to identify patients with cognitive symptoms who may have treatable conditions. Guidelines suggest that all patients presenting with dementia or cognitive symptoms should be evaluated with a range of laboratory tests, and with structural brain imaging with computed tomography (CT) or magnetic resonance imaging (MRI). While many of the disorders reported as ‘reversible...

  17. Microreactor System Design for a NASA In Situ Propellant Production Plant on Mars

    Science.gov (United States)

    TeGrotenhuis, W. E.; Wegeng, R. S.; Vanderwiel, D. P.; Whyatt, G. A.; Viswanathan, V. V.; Schielke, K. P.; Sanders, G. B.; Peters, T. A.; Nicholson, Leonard S. (Technical Monitor)

    2000-01-01

    , as well as three options for water decomposition, low temperature electrolysis, high temperature electrolysis, and thermochemical decomposition. Other elements of the plant include Sabatier and reverse water gas shift reactors, water recovery, chemical separations, and cryogenic storage. Data are presented supporting preliminary sizing of components, and results of the system design are compared to the existing NASA baseline that is based on conventional technologies.

  18. Production of biogas from organic waste in microreactors operated at two temperatures

    International Nuclear Information System (INIS)

    The process and the product of anaerobic digestion are evaluated for different proportions of organic substrates, in microreactors operated at thermophilic and mesophilic temperatures with interest to find alternatives that will generate energy from biomass. Small-scale tests are conducted to ensure the proper functioning of biodigesters and optimize operating conditions. The anaerobic digestion process is characterized in three manure mixing ratios: mix of leftovers (100:0,90:10 and 80:20) and two temperatures of work (35 degrees Celsius and 50 degrees Celsius), using a factorial arrangement with 2 replicates per treatment. The mixture is composed of manure, cow dung and scraps of fresh food (fruits and vegetables) and prepared food. The proportions were diluted to 5% total solids. Bottles are the experimental unit used consisting culture medium bottles of 1 liter with 500 mL of mixture. The test has run for 5 hydraulic retention times (HRT) of twenty days each. At this time the pH was evaluated, the daily production of biogas, biogas composition, total solids, volatile and fixed and the content of volatile fatty acids. The values obtained biogas productivity and CH4 content have been similar to those reported in the literature and indicate that the systems have been successful

  19. Preparation and evaluation of dual-enzyme microreactor with co-immobilized trypsin and chymotrypsin.

    Science.gov (United States)

    Meller, Kinga; Pomastowski, Paweł; Grzywiński, Damian; Szumski, Michał; Buszewski, Bogusław

    2016-04-01

    The preparation of capillary microfluidic reactor with co-immobilized trypsin and chymotrypsin with the use of a low-cost commercially available enzymatic reagent (containing these proteases) as well as the evaluation of its usefulness in proteomic research were presented. The monolithic copolymer synthesized from glycidyl methacrylate (GMA) and ethylene glycol dimethacrylate (EDMA) was used as a support. Firstly, the polymerization conditions were optimized and the monolithic bed was synthesized in the fused silica capillary modified with 3-(trimethoxysilyl)propyl methacrylate (γ-MAPS). The polymer containing epoxy groups was then modified with 1,6-diaminohexane, followed by the attachment of glutaraldehyde and immobilization of enzymes. The efficiency of the prepared monolithic Immobilized Enzyme Microreactor (μ-IMER) with regard to trypsin activity was evaluated using the low-molecular mass compound (Nα-benzoyl-l-arginine ethyl ester, BAEE). The activities of both enzymes were investigated using a macromolecular protein (human transferrin, Tf) as a substrate. In the case of BAEE, the reaction product was separated from the substrate using the capillary liquid chromatography and the efficiency of the reaction was determined by the peak area of the substrate. The hydrolysis products of transferrin were analyzed with MALDI-TOF which allows for the verification of the prepared enzymatic system applicability in the field of proteomic research. PMID:26947160

  20. Paper-based microreactor array for rapid screening of cell signaling cascades.

    Science.gov (United States)

    Huang, Chia-Hao; Lei, Kin Fong; Tsang, Ngan-Ming

    2016-08-01

    Investigation of cell signaling pathways is important for the study of pathogenesis of cancer. However, the related operations used in these studies are time consuming and labor intensive. Thus, the development of effective therapeutic strategies may be hampered. In this work, gel-free cell culture and subsequent immunoassay has been successfully integrated and conducted in a paper-based microreactor array. Study of the activation level of different kinases of cells stimulated by different conditions, i.e., IL-6 stimulation, starvation, and hypoxia, was demonstrated. Moreover, rapid screening of cell signaling cascades after the stimulations of HGF, doxorubicin, and UVB irradiation was respectively conducted to simultaneously screen 40 kinases and transcription factors. Activation of multi-signaling pathways could be identified and the correlation between signaling pathways was discussed to provide further information to investigate the entire signaling network. The present technique integrates most of the tedious operations using a single paper substrate, reduces sample and reagent consumption, and shortens the time required by the entire process. Therefore, it provides a first-tier rapid screening tool for the study of complicated signaling cascades. It is expected that the technique can be developed for routine protocol in conventional biological research laboratories. PMID:27377153

  1. VOF Modeling and Analysis of the Segmented Flow in Y-Shaped Microchannels for Microreactor Systems

    Directory of Open Access Journals (Sweden)

    Xian Wang

    2013-01-01

    Full Text Available Microscaled devices receive great attention in microreactor systems for producing high renewable energy due to higher surface-to-volume, higher transport rates (heat or/and mass transfer rates, and other advantages over conventional-size reactors. In this paper, the two-phase liquid-liquid flow in a microchannel with various Y-shaped junctions has been studied numerically. Two kinds of immiscible liquids were injected into a microchannel from the Y-shaped junctions to generate the segment flow mode. The segment length was studied. The volume of fluid (VOF method was used to track the liquid-liquid interface and the piecewise-liner interface construction (PLIC technique was adopted to get a sharp interface. The interfacial tension was simulated with continuum surface force (CSF model and the wall adhesion boundary condition was taken into consideration. The simulated flow pattern presents consistence with our experimental one. The numerical results show that a segmented flow mode appears in the main channel. Under the same inlet velocities of two liquids, the segment lengths of the two liquids are the same and depend on the inclined angles of two lateral channels. The effect of inlet velocity is studied in a typical T-shaped microchannel. It is found that the ratio between the lengths of two liquids is almost equal to the ratio between their inlet velocities.

  2. Grain boundaries as microreactors during reactive fluid flow: experimental dolomitization of a calcite marble

    Science.gov (United States)

    Etschmann, B.; Brugger, J.; Pearce, M. A.; Ta, C.; Brautigan, D.; Jung, M.; Pring, A.

    2014-08-01

    Limestone dolomitization is an example of a fluid-induced mineralogical transformation that commonly affects extensive rock volumes. To understand the mechanisms enabling these efficient replacement reactions, we investigated experimentally the dolomitization of a fractured calcite marble under flow-through conditions at mild hydrothermal conditions. Contrary to most earlier studies of coupled dissolution reprecipitation reactions that were conducted using small, individual grains, in this study, the integrity of the rock was preserved, so that the experiment explored the links between flow in a fracture and fluid-rock interaction. In these experiments, grain boundaries acted as microreactors, in which a Mg-poor `protodolomite' formed initially, and then transformed into dolomite. The difficulty in nucleating dolomite played a key role in controlling the evolution of the porosity, by allowing for (1) initial dissolution along grain boundaries, and (2) formation of coarse porosity at the reaction interface. This porosity evolution not only enabled the reaction to progress efficiently, but also controlled the mineralogy of the system, as shown by brucite replacing calcite near the fracture once the fluid along calcite grain boundaries became sufficiently connected to the fluid flowing through the fracture. This study illustrates the role of grain boundaries, porosity evolution and nucleation in controlling reaction progress as well as the nature and textures of the products in pervasive mineralogical transformations.

  3. X-ray absorption spectroscopy and imaging of heterogeneous hydrothermal mixtures using a diamond microreactor cell

    International Nuclear Information System (INIS)

    Hydrothermal synthesis is an important route to novel materials. Hydrothermal chemistry is also an important aspect of geochemistry and a variety of waste remediation technologies. There is a significant lack of information about the speciation of inorganic compounds under hydrothermal conditions. For these reasons we describe a high-temperature, high-pressure cell that allows one to acquire both x-ray absorption fine structure (XAFS) spectra and x-ray transmission and absorption images of heterogeneous hydrothermal mixtures. We demonstrate the utility of the method by measuring the Cu(I) speciation in a solution containing both solid and dissolved Cu phases at temperatures up to 325oC. X-ray imaging of the various hydrothermal phases allows micro-XAFS to be collected from different phases within the heterogeneous mixture. The complete structural characterization of a soluble bichloro-cuprous species was determined. In situ XAFS measurements were used to define the oxidation state and the first-shell coordination structure. The Cu--Cl distance was determined to be 2.12 Aa for the CuCl2- species and the complete loss of tightly bound waters of hydration in the first shell was observed. The microreactor cell described here can be used to test thermodynamic models of solubility and redox chemistry of a variety of different hydrothermal mixtures

  4. Optimization of [11C]DASB-synthesis: Vessel-based and flow-through microreactor methods

    International Nuclear Information System (INIS)

    The intention for the present study was to implement a microfluidic set-up for N-11C-methylations in a flow-through microreactor device with [11C]DASB as model-compound and [11C]CH3I and [11C]CH3OTf, respectively, as 11C-methylation agents. Due to an observed “aging” effect of the 11C-methylation agents' solution, this goal was not achieved. Nevertheless, based on these observations, the time consumption for the vessel-based routine production of [11C]DASB was reduced (34±1 min) and RCY was increased to 45.1±4.6% (EOB; 5.2±0.95 GBq EOS). - Highlights: ► Aging effect of 11C-methylation agents observed. ► Microfluidic set-up for remote 11C-methylations questionable. ► Vessel-based approach was ameliorated. ► Radiochem. yield of [11C]DASB was increased to 45.1±4.6% (EOB; 5.2±0.95 GBq EOS).

  5. A microreactor array for spatially resolved measurement of catalytic activity for high-throughput catalysis science

    Energy Technology Data Exchange (ETDEWEB)

    Kondratyuk, Petro; Gumuslu, Gamze; Shukla, Shantanu; Miller, James B; Morreale, Bryan D; Gellman, Andrew J

    2013-04-01

    We describe a 100 channel microreactor array capable of spatially resolved measurement of catalytic activity across the surface of a flat substrate. When used in conjunction with a composition spread alloy film (CSAF, e.g. Pd{sub x}Cu{sub y}Au{sub 1-x-y}) across which component concentrations vary smoothly, such measurements permit high-throughput analysis of catalytic activity and selectivity as a function of catalyst composition. In the reported implementation, the system achieves spatial resolution of 1 mm{sup 2} over a 10×10 mm{sup 2} area. During operation, the reactant gases are delivered at constant flow rate to 100 points of differing composition on the CSAF surface by means of a 100-channel microfluidic device. After coming into contact with the CSAF catalyst surface, the product gas mixture from each of the 100 points is withdrawn separately through a set of 100 isolated channels for analysis using a mass spectrometer. We demonstrate the operation of the device on a Pd{sub x}Cu{sub y}Au{sub 1-x-y} CSAF catalyzing the H{sub 2}-D{sub 2} exchange reaction at 333 K. In essentially a single experiment, we measured the catalytic activity over a broad swathe of concentrations from the ternary composition space of the Pd{sub x}Cu{sub y}Au{sub 1-x-y} alloy.

  6. Controlling the quality of nanocrystalline silicon made by hot-wire chemical vapor deposition by using a reverse H2 profiling technique

    NARCIS (Netherlands)

    Li, H. B. T.; Franken, R.H.; Stolk, R.L.; van der Werf, C.H.M.; Rath, J.K.; Schropp, R.E.I.

    2008-01-01

    Hydrogen profiling, i.e., decreasing the H2 dilution during deposition, is a well-known technique to maintain a proper crystalline ratio of the nanocrystalline (nc-Si:H) absorber layers of plasma-enhanced chemical vapor-deposited (PECVD) thin film solar cells. With this technique a large increase in

  7. Quasi-classical trajectory study of the reaction N(4S) + H2 and its reverse reaction: Role of initial vibrational and rotational excitations in chemical stereodynamics

    Indian Academy of Sciences (India)

    Juan Zhang; Shunle Dong

    2013-07-01

    To investigate the effects of reagent vibrational and rotational states on the stereodynamical properties of the N(4S) + H2(, )→NH + H reaction and its reverse reaction of H(2S) + NH(, )→N(4S) + H2, we reported a detailed quasiclassical trajectory study using the 4A" double many-body expansion potential energy surface and at the collision energy of 35 kcal/mol. The density distribution of (r) as a function of the angle between and ', and that of (r) as a function of the dihedral angle between the plane containing -' and the plane containing '- ', the normal differential cross-sections as well as the averaged product rotational alignment parameter 〈 2('.) 〉 are calculated and reported. Comparison between the two reactions has showed that the degrees of alignment and orientation of products related to reagent rovibrational state have marked differences for the two reactive systems.

  8. The influence of the "cage" effect on the mechanism of reversible bimolecular multistage chemical reactions proceeding from different sites in solutions.

    Science.gov (United States)

    Doktorov, Alexander B

    2016-08-28

    Manifestations of the "cage" effect at the encounters of reactants have been theoretically treated on the example of multistage reactions (including bimolecular exchange reactions as elementary stages) proceeding from different active sites in liquid solutions. It is shown that for reactions occurring near the contact of reactants, consistent consideration of quasi-stationary kinetics of such multistage reactions (possible in the framework of the encounter theory only) can be made on the basis of chemical concepts of the "cage complex," just as in the case of one-site model described in the literature. Exactly as in the one-site model, the presence of the "cage" effect gives rise to new channels of reactant transformation that cannot result from elementary event of chemical conversion for the given reaction mechanism. Besides, the multisite model demonstrates new (as compared to one-site model) features of multistage reaction course. PMID:27586911

  9. Controlling the quality of nanocrystalline silicon made by hot-wire chemical vapor deposition by using a reverse H2 profiling technique

    OpenAIRE

    Li, H. B. T.; Franken, R.H.; Stolk, R.L.; van der Werf, C.H.M.; J.K. Rath; Schropp, R.E.I.

    2008-01-01

    Hydrogen profiling, i.e., decreasing the H2 dilution during deposition, is a well-known technique to maintain a proper crystalline ratio of the nanocrystalline (nc-Si:H) absorber layers of plasma-enhanced chemical vapor-deposited (PECVD) thin film solar cells. With this technique a large increase in the energy conversion efficiency is obtained. Compared to PECVD, the unique characteristics of hot-wire CVD (HWCVD), such as the catalytic reactions, the absence of ion bombardment, the substrate ...

  10. PMMA microreactor for chemiluminescence detection of Cu (II) based on 1,10-Phenanthroline-hydrogen peroxide reaction.

    Science.gov (United States)

    Chen, Xueye; Shen, Jienan; Li, Tiechuan

    2016-01-01

    A microreactor for the chemiluminescence detection of copper (II) in water samples, based on the measurement of light emitted from the copper (II) catalysed oxidation of 1,10-phenanthroline by hydrogen peroxide in basic aqueous solution, is presented. Polymethyl methacrylate (PMMA) was chose as material for fabricating the microreactor with mill and hot bonding method. Optimized reagents conditions were found to be 6.3 × 10(-5)mol/L 1,10-phenanthroline, 1.5 × 10(-3)mol/L hydrogen peroxide, 7.0 × 10(-2)mol/L sodium hydroxide and 2.4 × 10(-5)mol/L Hexadecyl trimethyl ammonium Bromide (CTMAB). In the continuous flow injection mode the system can perform fully automated detection with a reagent consumption of only 3.5 μL each time. The linear range of the Cu (II) ions concentration was 1.5 × 10(-8) mol/L to 1.0 × 10(-4) mol/L, and the detection limit was 9.4 × 10(-9)mol/L with the S/N ratio of 4. The relative standard deviation was 3.0 % for 2.0 × 10(-6) mol/L Cu (II) ions (n = 10). The most obvious features of the detection method are simplicity, rapidity and easy fabrication of the microreactor. PMID:26788016

  11. Pyrolysis of the Simplest Carbohydrate, Glycolaldehyde (CHO-CH2OH), and Glyoxal in a Heated Microreactor.

    Science.gov (United States)

    Porterfield, Jessica P; Baraban, Joshua H; Troy, Tyler P; Ahmed, Musahid; McCarthy, Michael C; Morgan, Kathleen M; Daily, John W; Nguyen, Thanh Lam; Stanton, John F; Ellison, G Barney

    2016-04-14

    Both glycolaldehyde and glyoxal were pyrolyzed in a set of flash-pyrolysis microreactors. The pyrolysis products resulting from CHO-CH2OH and HCO-CHO were detected and identified by vacuum ultraviolet (VUV) photoionization mass spectrometry. Complementary product identification was provided by argon matrix infrared absorption spectroscopy. Pyrolysis pressures in the microreactor were about 100 Torr, and contact times with the microreactors were roughly 100 μs. At 1200 K, the products of glycolaldehyde pyrolysis are H atoms, CO, CH2═O, CH2═C═O, and HCO-CHO. Thermal decomposition of HCO-CHO was studied with pulsed 118.2 nm photoionization mass spectrometry and matrix infrared absorption. Under these conditions, glyoxal undergoes pyrolysis to H atoms and CO. Tunable VUV photoionization mass spectrometry provides a lower bound for the ionization energy (IE)(CHO-CH2OH) ≥ 9.95 ± 0.05 eV. The gas-phase heat of formation of glycolaldehyde was established by a sequence of calorimetric experiments. The experimental result is ΔfH298(CHO-CH2OH) = -75.8 ± 1.3 kcal mol(-1). Fully ab initio, coupled cluster calculations predict ΔfH0(CHO-CH2OH) of -73.1 ± 0.5 kcal mol(-1) and ΔfH298(CHO-CH2OH) of -76.1 ± 0.5 kcal mol(-1). The coupled-cluster singles doubles and noniterative triples correction calculations also lead to a revision of the geometry of CHO-CH2OH. We find that the O-H bond length differs substantially from earlier experimental estimates, due to unusual zero-point contributions to the moments of inertia. PMID:26979134

  12. A multi-enzyme microreactor-based online electrochemical system for selective and continuous monitoring of acetylcholine.

    Science.gov (United States)

    Lin, Yuqing; Yu, Ping; Mao, Lanqun

    2015-06-01

    This study demonstrates an online electrochemical system (OECS) for selective and continuous measurements of acetylcholine (ACh) through efficiently integrating in vivo microdialysis, a multi-enzyme microreactor and an electrochemical detector. A multi-enzyme microreactor was prepared first by co-immobilizing two kinds of enzymes, i.e. choline oxidase (ChOx) and catalase (Cat), onto magnetite nanoparticles and then confining the as-formed nanoparticles into a fused-silica capillary with the assistance of an external magnet. The multi-enzyme microreactor was settled between an in vivo microdialysis sampling system and an electrochemical detector to suppress the interference from choline toward ACh detection. Selective detection of ACh was accomplished using the electrochemical detector with ACh esterase (AChE) and ChOx as the recognition units for ACh and Prussian blue (PB) as the electrocatalyst for the reduction of hydrogen peroxide (H2O2). The current recorded with the OECS was linear with the concentration of ACh (I/nA = -3.90CACh/μM + 1.21, γ = 0.998) within a concentration range of 5 μM to 100 μM. The detection limit, based on a signal-to-noise ratio of 3, was calculated to be 1 μM. Interference investigation demonstrates that the OECS did not produce an observable current response toward physiological levels of common electroactive species, such as ascorbic acid (AA), dopamine (DA), 3,4-dihydroxyphenylacetic acid (DOPAC), and uric acid (UA). The high selectivity and the good linearity in combination with the high stability may enable the OECS developed here as a potential system for continuous monitoring of cerebral ACh release in some physiological and pathological processes. PMID:25529471

  13. Reversible Statistics

    DEFF Research Database (Denmark)

    Tryggestad, Kjell

    2004-01-01

    The study aims is to describe how the inclusion and exclusion of materials and calculative devices construct the boundaries and distinctions between statistical facts and artifacts in economics. My methodological approach is inspired by John Graunt's (1667) Political arithmetic and more recent work...... within constructivism and the field of Science and Technology Studies (STS). The result of this approach is here termed reversible statistics, reconstructing the findings of a statistical study within economics in three different ways. It is argued that all three accounts are quite normal, albeit in...... different ways. The presence and absence of diverse materials, both natural and political, is what distinguishes them from each other. Arguments are presented for a more symmetric relation between the scientific statistical text and the reader. I will argue that a more symmetric relation can be achieved by...

  14. Chemical ordering in Pd$_{81}$Ge$_{19}$ metallic glass studied by reverse Monte-Carlo modelling of XRD, ND and EXAFS experimental data

    CERN Document Server

    Pethes, Ildikó; Stoica, Mihai; Beuneu, Brigitte; Jóvári, Pál

    2016-01-01

    Pd$_{81}$Ge$_{19}$ metallic glass was investigated by neutron diffraction, X-ray diffraction and extended X-ray absorption fine structure spectroscopy (EXAFS) at the Ge K-edge. Large scale structural models were obtained by fitting the three measurements simultaneously in the framework of the reverse Monte Carlo simulation technique. It was found that the experimental data sets can be adequately fitted without Ge-Ge nearest neighbours. Mean Pd-Pd and Pd-Ge distances are 2.80$\\pm$0.02 {\\AA} and 2.50$\\pm$0.02 {\\AA}, respectively. The total average coordination number of Pd is 12.1$\\pm$0.5 while Ge is surrounded by 10.6$\\pm$1.1 Pd atoms. The coordination numbers calculated from partial pair correlation functions were compared to those obtained by Voronoi tessellation method. It was found that the latter technique overestimates the number of nearest neighbours by about 20% due to the significant contribution of distant pairs.

  15. Use of a continuous-flow microreactor for thiol-ene functionalization of RAFT-derived poly(butyl acrylate)

    OpenAIRE

    Vandenbergh, Joke; Junkers, Thomas

    2012-01-01

    This study describes the synthesis of functionalized RAFT-derived poly(n-butyl acrylate) polymers via the use of a continuous-flow microreactor, in which aminolysis as well as thiol-ene reactions are executed in reaction times of just 20 minutes. Poly(n-butyl acrylate) (M-n = 3800 g mol(-1), PDI = 1.10) with a trithiocarbonate end group was prepared via a conventional RAFT process. The polymer was then functionalized via aminolysis/thiol-ene reactions in the micro-flow reactor with isobornyl ...

  16. ZnO一维纳米结构修饰的微反应器的构建及其催化性能研究%Fabrication of ZnO One-dimensional Nanostructure Modified Microreactor and Its Catalytic Performance Research

    Institute of Scientific and Technical Information of China (English)

    张权; 王宏志; 李耀刚; 张青红

    2013-01-01

    Pd/ZnO one-dimensional nanostructure modified micmreactor was successfully fabricated simply by pumping a Pd sol into the microchannel containing preformed ZnO one-dimensional nanostructure,which was constructed through a wet chemical route.The morphology and structure of Pd/ ZnO one-dimensional nanostructure were characterized through FE-SEM,XRD,EDX,TEM et al.The results showed that the Pd/ZnO one-dimensional nanostructure were uniform and their thickness was about 2-3 μm.The microreactor was used for catalysing Heck coupling reaction.The result showed that it just cost 40 min when the yield reached 100% by using the microreactor,while,it would cost more than 120 min in a flask.Thus,the Pd/ZnO one-dimensional nanostructure modified microreactor was a microreactor with the fast and high efficient catalytic performance.%采用湿化学的方法将ZnO一维纳米结构定向生长于石英毛细管微通道反应器内壁,并通过将Pd溶胶直接包覆于ZnO一维纳米结构表面的方法,制备得到Pd/ZnO一维纳米结构修饰的微反应器.采用FE-SEM、XRD、EDX、TEM等测试方法对Pd/ZnO一维纳米结构的形貌结构进行表征,结果表明Pd/ZnO一维纳米结构形貌规整均一,厚度约2~3μm,Pd均匀的包覆在ZnO纳米棒表面;Pd为立方相单质.利用该微反应器进行催化Heck偶联反应,在反应时间为40min时其产率达到100%,而在烧瓶内进行却至少需要120 min,因此,该反应器具有快速高效的催化效果.

  17. Parametric constraints on the dynamic behavior of immobilized enzyme kinetics in a microreactor

    Directory of Open Access Journals (Sweden)

    Pratap R Patnaik

    2011-08-01

    Full Text Available Normal 0 false false false EN-US X-NONE X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;} The observed kinetics of reactions catalyzed by immobilized enzymes in microreactors may differ from their kinetics in well-mixed solution-phase reactors. While the steady-state differences have been analyzed before, the time-dependent differences have not been explored. In the present study, therefore, an initial feasibility analysis has been conducted to identify permissible regions for the kinetic parameters for dynamics solutions to exist. For a reaction catalyzed by alkaline phosphatase, it has been shown that the choices of the values of three vital parameters are inter-related and restricted to certain nonlinear loci. These limits add to the limits imposed by thermodynamic requirements, and they are important in determining dynamic behavior.  

  18. Screen printing as a holistic manufacturing method for multifunctional microsystems and microreactors

    Science.gov (United States)

    Bejarano, D.; Lozano, P.; Mata, D.; Cito, S.; Constantí, M.; Katakis, I.

    2009-11-01

    Microsystems are commonly manufactured by photolithographic or injection moulding techniques in a variety of realizations and on almost any material. A perennial problem in the manufacturing of microsystems is the difficulty to obtain hybrid devices that incorporate distinct materials with different functionalities. In most of the cases, cumbersome prototyping and high investment needed for manufacturing are additional problems that add to the cost of the final product. Such drawbacks are true not only for lab-on-a-chip but also for certain microreactor applications. Most importantly, in many commercial applications where an intermediate product between full fluidics control and a 'strip' is needed, such restraints prohibit the feasibility of reduction to practice. Screen printing on the other hand is a low cost technique that has been used for years in mass producing two-dimensional low cost reproductions of a mask pattern for circuits and art incorporates prototyping in production and allows the use of an almost limitless variety of materials as 'inks'. In this work it is demonstrated that taking advantage of the deposited ink's three-dimensional nature, screen printing can be used as a versatile and low cost technique for the fabrication of microchannels. Microchannels with dimensions in the order of 100 µm were fabricated that could readily incorporate functionalities through the choice of the materials used to create the microstructure. Variables have been investigated through a factorial experimental design as important process parameters that affect the resolution and print thickness of the resulting microchannels that incorporate electroactive elements. Such studies can lead to the optimization of the process for custom applications.

  19. Fabrication and characteristics of cube-post microreactors for methanol steam reforming

    International Nuclear Information System (INIS)

    Highlights: ► We developed a cube-post microreactor for methanol steam reforming. ► We investigated the influences of micro-milling parameters on the burr formation during fabricating the cube posts. ► Larger cutting speed, smaller feed rate and cutting depth are in favor of obtaining relatively small burrs. ► Cube post and manifold structure show important effects on reaction performances at relatively low reaction temperature. -- Abstract: The lamination-plate structure patterned with microchannels and triangle manifolds regarded as one of the preferred constructions for micro fuel reformers. Learned from the microchannel plate structure, a similar plate structure with cube-post array and triangle manifolds is proposed in this work. A micro-milling process is applied to fabricate the cube posts on the plate surface, and the influences of cutting parameters on the burr formation are analyzed. Experimental results indicate that larger cutting speed, smaller feed rate and cutting depth are in favor of obtaining relatively small burrs. Two plates with different cube-post dimensions and manifold structures are experimentally investigated the performances of methanol steam reforming over the Cu/Zn/Al/Zr catalyst. It indicates that the reactor with small-scale cube posts and acute triangle manifold presents better reforming performances at 260 °C than that of the one with large-scale cube posts and right triangle manifolds. However, their performances are closed to each other at relatively high reaction temperature since the catalyst activity is situated in dominated position at the time.

  20. Simultaneous detection of forbidden chemical residues in milk using dual-label time-resolved reverse competitive chemiluminescent immunoassay based on amine group functionalized surface.

    Directory of Open Access Journals (Sweden)

    Dongdong Zhang

    Full Text Available In this study, a sensitive dual-label time-resolved reverse competitive chemiluminescent immunoassay was developed for simultaneous detection of chloramphenicol (CAP and clenbuterol (CLE in milk. The strategy was performed based on the distinction of the kinetic characteristics of horseradish peroxidase (HRP and alkaline phosphatase (ALP in chemiluminesecence (CL systems and different orders of magnitude in HRP CL value for CAP and ALP CL value for CLE in the chemiluminescent immunoassay. Capture antibodies were covalently bound to the amine group functionalized chemiluminescent microtiter plate (MTP for efficient binding of detection antibodies for the enzymes labeled CAP (HRP-CAP and CLE (ALP-CLE. The CL signals were recorded at different time points by the automatic luminometers with significant distinction in the dynamic curves. When we considered the ALP CL value (about 10(5 of CLE as background for HRP CL signal value (about 10(7 of CAP, there was no interaction from ALP CL background of CLE and the differentiation of CAP and CLE can be easily achieved. The 50% inhibition concentration (IC50 values of CAP and CLE in milk samples were 0.00501 µg L(-1 and 0.0128 µg L(-1, with the ranges from 0.0003 µg L(-1 to 0.0912 µg L(-1 and from 0.00385 µg L(-1 to 0.125 µg L(-1, respectively. The developed method is more sensitive and of less duration than the commercial ELISA kits, suitable for simultaneous screening of CAP and CLE.

  1. Analysis of Phenacylester Derivatives of Fatty Acids from Human Skin Surface Sebum by Reversed-Phase HPLC: Chromatographic Mobility as a Function of Physico-Chemical Properties

    Science.gov (United States)

    Bodoprost, Juliana; Rosemeyer, Helmut

    2007-01-01

    A set of 13 fatty acids was transformed into their phenacyl esters by reaction with phenacyl bromide in acetonitrile using 18-crown-6 as phase-transfer catalyst. Conditions for the RP-18 HPL chromatographic separation of most of the esters has been worked out. Using this standard the fatty acid spectra from skin surface sebum lipids of 17 test persons was taken after microwave-assisted hydrolysis, neutralization and extraction with n-hexane. Quantitative evaluation of the chromatograms exhibits that oleic acid predominates in the sebum of all test persons. In the second part of the work the chromatographic mobility (RE values) of fatty acid phenacyl esters is correlated with calculated physico-chemical parameters of the corresponding acids. The best linear correlation was found between the RE and the logP values. This is helpful for the structural elucidation of un-identified fatty acids in a chromatogram.

  2. High mass resolution time of flight mass spectrometer for measuring products in heterogeneous catalysis in highly sensitive microreactors

    Science.gov (United States)

    Andersen, T.; Jensen, R.; Christensen, M. K.; Pedersen, T.; Hansen, O.; Chorkendorff, I.

    2012-07-01

    We demonstrate a combined microreactor and time of flight system for testing and characterization of heterogeneous catalysts with high resolution mass spectrometry and high sensitivity. Catalyst testing is performed in silicon-based microreactors which have high sensitivity and fast thermal response. Gas analysis is performed with a time of flight mass spectrometer with a modified nude Bayard-Alpert ionization gauge as gas ionization source. The mass resolution of the time of flight mass spectrometer using the ion gauge as ionization source is estimated to m/Δm > 2500. The system design is superior to conventional batch and flow reactors with accompanying product detection by quadrupole mass spectrometry or gas chromatography not only due to the high sensitivity, fast temperature response, high mass resolution, and fast acquisition time of mass spectra but it also allows wide mass range (0-5000 amu in the current configuration). As a demonstration of the system performance we present data from ammonia oxidation on a Pt thin film showing resolved spectra of OH and NH3.

  3. High mass resolution time of flight mass spectrometer for measuring products in heterogeneous catalysis in highly sensitive microreactors

    Energy Technology Data Exchange (ETDEWEB)

    Andersen, T.; Jensen, R.; Christensen, M. K.; Chorkendorff, I. [Department of Physics, Danish National Research Foundation' s Center for Individual Nanoparticle Functionality (CINF), Technical University of Denmark, Building 312, DK-2800 Kgs. Lyngby (Denmark); Pedersen, T.; Hansen, O. [Department of Micro- and Nanotechnology, Technical University of Denmark, DTU Nanotech Building 345 East, DK-2800 Kgs. Lyngby (Denmark)

    2012-07-15

    We demonstrate a combined microreactor and time of flight system for testing and characterization of heterogeneous catalysts with high resolution mass spectrometry and high sensitivity. Catalyst testing is performed in silicon-based microreactors which have high sensitivity and fast thermal response. Gas analysis is performed with a time of flight mass spectrometer with a modified nude Bayard-Alpert ionization gauge as gas ionization source. The mass resolution of the time of flight mass spectrometer using the ion gauge as ionization source is estimated to m/{Delta}m > 2500. The system design is superior to conventional batch and flow reactors with accompanying product detection by quadrupole mass spectrometry or gas chromatography not only due to the high sensitivity, fast temperature response, high mass resolution, and fast acquisition time of mass spectra but it also allows wide mass range (0-5000 amu in the current configuration). As a demonstration of the system performance we present data from ammonia oxidation on a Pt thin film showing resolved spectra of OH and NH{sub 3}.

  4. Determination of the inhibitory effect of green tea extract on glucose-6-phosphate dehydrogenase based on multilayer capillary enzyme microreactor.

    Science.gov (United States)

    Camara, Mohamed Amara; Tian, Miaomiao; Liu, Xiaoxia; Liu, Xin; Wang, Yujia; Yang, Jiqing; Yang, Li

    2016-08-01

    Natural herbal medicines are an important source of enzyme inhibitors for the discovery of new drugs. A number of natural extracts such as green tea have been used in prevention and treatment of diseases due to their low-cost, low toxicity and good performance. The present study reports an online assay of the activity and inhibition of the green tea extract of the Glucose 6-phosphate dehydrogenase (G6PDH) enzyme using multilayer capillary electrophoresis based immobilized enzyme microreactors (CE-IMERs). The multilayer CE-IMERs were produced with layer-by-layer electrostatic assembly, which can easily enhance the enzyme loading capacity of the microreactor. The activity of the G6PDH enzyme was determined and the enzyme inhibition by the inhibitors from green tea extract was investigated using online assay of the multilayer CE-IMERs. The Michaelis constant (Km ) of the enzyme, the IC50 and Ki values of the inhibitors were achieved and found to agree with those obtained using offline assays. The results show a competitive inhibition of green tea extract on the G6PDH enzyme. The present study provides an efficient and easy-to-operate approach for determining G6PDH enzyme reaction and the inhibition of green tea extract, which may be beneficial in research and the development of natural herbal medicines. Copyright © 2016 John Wiley & Sons, Ltd. PMID:26659432

  5. High mass resolution time of flight mass spectrometer for measuring products in heterogeneous catalysis in highly sensitive microreactors.

    Science.gov (United States)

    Andersen, T; Jensen, R; Christensen, M K; Pedersen, T; Hansen, O; Chorkendorff, I

    2012-07-01

    We demonstrate a combined microreactor and time of flight system for testing and characterization of heterogeneous catalysts with high resolution mass spectrometry and high sensitivity. Catalyst testing is performed in silicon-based microreactors which have high sensitivity and fast thermal response. Gas analysis is performed with a time of flight mass spectrometer with a modified nude Bayard-Alpert ionization gauge as gas ionization source. The mass resolution of the time of flight mass spectrometer using the ion gauge as ionization source is estimated to m/Δm > 2500. The system design is superior to conventional batch and flow reactors with accompanying product detection by quadrupole mass spectrometry or gas chromatography not only due to the high sensitivity, fast temperature response, high mass resolution, and fast acquisition time of mass spectra but it also allows wide mass range (0-5000 amu in the current configuration). As a demonstration of the system performance we present data from ammonia oxidation on a Pt thin film showing resolved spectra of OH and NH(3). PMID:22852722

  6. High mass resolution time of flight mass spectrometer for measuring products in heterogeneous catalysis in highly sensitive microreactors

    International Nuclear Information System (INIS)

    We demonstrate a combined microreactor and time of flight system for testing and characterization of heterogeneous catalysts with high resolution mass spectrometry and high sensitivity. Catalyst testing is performed in silicon-based microreactors which have high sensitivity and fast thermal response. Gas analysis is performed with a time of flight mass spectrometer with a modified nude Bayard-Alpert ionization gauge as gas ionization source. The mass resolution of the time of flight mass spectrometer using the ion gauge as ionization source is estimated to m/Δm > 2500. The system design is superior to conventional batch and flow reactors with accompanying product detection by quadrupole mass spectrometry or gas chromatography not only due to the high sensitivity, fast temperature response, high mass resolution, and fast acquisition time of mass spectra but it also allows wide mass range (0–5000 amu in the current configuration). As a demonstration of the system performance we present data from ammonia oxidation on a Pt thin film showing resolved spectra of OH and NH3.

  7. 微反应器制备无机材料的应用进展%Application progress of microreactors in synthesis of inorganic materials

    Institute of Scientific and Technical Information of China (English)

    曹寅; 杨晖

    2011-01-01

    简述了微反应器近些年的发展及微反应器的定义、分类和优点.综述了微反应器在制备无机颗粒材料方面的研究进展,介绍了制备过程中一些可控因素对产物的影响,着重介绍了某些微反应器与间歇反应器在制备无机颗粒材料方面的差异,总结了微反应器在合成材料上的优势,并且对微反应器在无极颗粒材料合成中的应用前景做了展望.%Development in recent years,definition, classification, and advantages of microreactors were briefly introduced. Application progress of microreactors in synthesis of inoganic materials was reviewed and the influence of some controllable factors on products during the synthesis process were discussed in detail. Differences between inorganic materials prepared by certain microreactor and by batch reactor were emphatically elaborated. Prospect of the application of microreactors in synthesis of inorganic materials was also forecasted.

  8. Ruthenium catalyst on carbon nanofiber support layers for use in silicon-based structured microreactors, Part II: Catalytic reduction of bromate contaminants in aqueous phase

    NARCIS (Netherlands)

    Thakur, D.B.; Tiggelaar, R.M.; Weber, Y.; Gardeniers, J.G.E.; Lefferts, L.; Seshan, K.

    2011-01-01

    Catalyst layers were synthesized inside a structured channel of silicon based microreactor and used to remove bromate contaminants in water. It is demonstrated that Ru/CNF based catalyst is active for bromate reduction, resulting in turn over frequencies (TOFs) higher than conventional powdered cata

  9. Novel micro-reactor flow cell for investigation of model catalysts using in situ grazing-incidence X-ray scattering

    DEFF Research Database (Denmark)

    Kehres, Jan; Pedersen, Thomas; Masini, Federico;

    2016-01-01

    The design, fabrication and performance of a novel and highly sensitive micro-reactor device for performing in situ grazing-incidence X-ray scattering experiments of model catalyst systems is presented. The design of the reaction chamber, etched in silicon on insulator (SIO), permits grazing-inci...

  10. Development of a fully integrated falling film microreactor for gas-liquid-solid biotransformation with surface immobilized O2 -dependent enzyme.

    Science.gov (United States)

    Bolivar, Juan M; Krämer, Christina E M; Ungerböck, Birgit; Mayr, Torsten; Nidetzky, Bernd

    2016-09-01

    Microstructured flow reactors are powerful tools for the development of multiphase biocatalytic transformations. To expand their current application also to O2 -dependent enzymatic conversions, we have implemented a fully integrated falling film microreactor that provides controllable countercurrent gas-liquid phase contacting in a multi-channel microstructured reaction plate. Advanced non-invasive optical sensing is applied to measure liquid-phase oxygen concentrations in both in- and out-flow as well as directly in the microchannels (width: 600 μm; depth: 200 μm). Protein-surface interactions are designed for direct immobilization of catalyst on microchannel walls. Target enzyme (here: d-amino acid oxidase) is fused to the positively charged mini-protein Zbasic2 and the channel surface contains a negatively charged γ-Al2 O3 wash-coat layer. Non-covalent wall attachment of the chimeric Zbasic2 _oxidase resulted in fully reversible enzyme immobilization with fairly uniform surface coverage and near complete retention of biological activity. The falling film at different gas and liquid flow rates as well as reactor inclination angles was shown to be mostly wavy laminar. The calculated film thickness was in the range 0.5-1.3 × 10(-4)  m. Direct O2 concentration measurements at the channel surface demonstrated that the liquid side mass transfer coefficient (KL ) for O2 governed the overall gas/liquid/solid mass transfer and that the O2 transfer rate (≥0.75 mM · s(-1) ) vastly exceeded the maximum enzymatic reaction rate in a wide range of conditions. A value of 7.5 (±0.5) s(-1) was determined for the overall mass transfer coefficient KL a, comprising a KL of about 7 × 10(-5)  m · s(-1) and a specific surface area of up to 10(5)  m(-1) . Biotechnol. Bioeng. 2016;113: 1862-1872. © 2016 Wiley Periodicals, Inc. PMID:26927978

  11. Multiple stimulus reversible hydrogels

    Science.gov (United States)

    Gutowska, Anna; Krzyminski, Karol J.

    2006-04-25

    A polymeric solution capable of gelling upon exposure to a critical minimum value of a plurality of environmental stimuli is disclosed. The polymeric solution may be an aqueous solution utilized in vivo and capable of having the gelation reversed if at least one of the stimuli fall below, or outside the range of, the critical minimum value. The aqueous polymeric solution can be used either in industrial or pharmaceutical environments. In the medical environment, the aqueous polymeric solution is provided with either a chemical or radioisotopic therapeutic agent for delivery to a specific body part. The primary advantage of the process is that exposure to one environmental stimuli alone will not cause gelation, thereby enabling the therapeutic agent to be conducted through the body for relatively long distances without gelation occurring.

  12. Mimicking insect communication: release and detection of pheromone, biosynthesized by an alcohol acetyl transferase immobilized in a microreactor.

    Directory of Open Access Journals (Sweden)

    Lourdes Muñoz

    Full Text Available Infochemical production, release and detection of (Z,E-9,11-tetradecadienyl acetate, the major component of the pheromone of the moth Spodoptera littoralis, is achieved in a novel microfluidic system designed to mimic the final step of the pheromone biosynthesis by immobilized recombinant alcohol acetyl transferase. The microfluidic system is part of an "artificial gland", i.e., a chemoemitter that comprises a microreactor connected to a microevaporator and is able to produce and release a pre-defined amount of the major component of the pheromone from the corresponding (Z,E-9,11-tetradecadienol. Performance of the entire chemoemitter has been assessed in electrophysiological and behavioral experiments. Electroantennographic depolarizations of the pheromone produced by the chemoemitter were ca. 40% relative to that evoked by the synthetic pheromone. In a wind tunnel, the pheromone released from the evaporator elicited on males a similar attraction behavior as 3 virgin females in most of the parameters considered.

  13. The thermal decomposition of the benzyl radical in a heated micro-reactor. II. Pyrolysis of the tropyl radical

    Energy Technology Data Exchange (ETDEWEB)

    Buckingham, Grant T. [Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309-0215, USA; National Bioenergy Center, National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden Colorado 80401, USA; Porterfield, Jessica P. [Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309-0215, USA; Kostko, Oleg [Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA; Troy, Tyler P. [Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA; Ahmed, Musahid [Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA; Robichaud, David J. [National Bioenergy Center, National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden Colorado 80401, USA; Nimlos, Mark R. [National Bioenergy Center, National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden Colorado 80401, USA; Daily, John W. [Department of Mechanical Engineering, Center for Combustion and Environmental Research, University of Colorado, Boulder, Colorado 80309-0427, USA; Ellison, G. Barney [Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309-0215, USA

    2016-07-05

    Cycloheptatrienyl (tropyl) radical, C7H7, was cleanly produced in the gas-phase, entrained in He or Ne carrier gas, and subjected to a set of flash-pyrolysis micro-reactors. The pyrolysis products resulting from C7H7 were detected and identified by vacuum ultraviolet photoionization mass spectrometry. Complementary product identification was provided by infrared absorption spectroscopy. Pyrolysis pressures in the micro-reactor were roughly 200 Torr and residence times were approximately 100 us. Thermal cracking of tropyl radical begins at 1100 K and the products from pyrolysis of C7H7 are only acetylene and cyclopentadienyl radicals. Tropyl radicals do not isomerize to benzyl radicals at reactor temperatures up to 1600 K. Heating samples of either cycloheptatriene or norbornadiene never produced tropyl (C7H7) radicals but rather only benzyl (C6H5CH2). The thermal decomposition of benzyl radicals has been reconsidered without participation of tropyl radicals. There are at least three distinct pathways for pyrolysis of benzyl radical: the Benson fragmentation, the methyl-phenyl radical, and the bridgehead norbornadienyl radical. These three pathways account for the majority of the products detected following pyrolysis of all of the isotopomers: C6H5CH2, C6H5CD2, C6D5CH2, and C6H5 13CH2. Analysis of the temperature dependence for the pyrolysis of the isotopic species (C6H5CD2, C6D5CH2, and C6H5 13CH2) suggests the Benson fragmentation and the norbornadienyl pathways open at reactor temperatures of 1300 K while the methyl-phenyl radical channel becomes active at slightly higher temperatures (1500 K).

  14. The thermal decomposition of the benzyl radical in a heated micro-reactor. II. Pyrolysis of the tropyl radical

    Science.gov (United States)

    Buckingham, Grant T.; Porterfield, Jessica P.; Kostko, Oleg; Troy, Tyler P.; Ahmed, Musahid; Robichaud, David J.; Nimlos, Mark R.; Daily, John W.; Ellison, G. Barney

    2016-07-01

    Cycloheptatrienyl (tropyl) radical, C7H7, was cleanly produced in the gas-phase, entrained in He or Ne carrier gas, and subjected to a set of flash-pyrolysis micro-reactors. The pyrolysis products resulting from C7H7 were detected and identified by vacuum ultraviolet photoionization mass spectrometry. Complementary product identification was provided by infrared absorption spectroscopy. Pyrolysis pressures in the micro-reactor were roughly 200 Torr and residence times were approximately 100 μs. Thermal cracking of tropyl radical begins at 1100 K and the products from pyrolysis of C7H7 are only acetylene and cyclopentadienyl radicals. Tropyl radicals do not isomerize to benzyl radicals at reactor temperatures up to 1600 K. Heating samples of either cycloheptatriene or norbornadiene never produced tropyl (C7H7) radicals but rather only benzyl (C6H5CH2). The thermal decomposition of benzyl radicals has been reconsidered without participation of tropyl radicals. There are at least three distinct pathways for pyrolysis of benzyl radical: the Benson fragmentation, the methyl-phenyl radical, and the bridgehead norbornadienyl radical. These three pathways account for the majority of the products detected following pyrolysis of all of the isotopomers: C6H5CH2, C6H5CD2, C6D5CH2, and C6H513CH2. Analysis of the temperature dependence for the pyrolysis of the isotopic species (C6H5CD2, C6D5CH2, and C6H513CH2) suggests the Benson fragmentation and the norbornadienyl pathways open at reactor temperatures of 1300 K while the methyl-phenyl radical channel becomes active at slightly higher temperatures (1500 K).

  15. 整体固定化酶反应器的研制%Construction of a monolithic trypsin enzymatic microreactor

    Institute of Scientific and Technical Information of China (English)

    李建军; 贺娜; 王骊丽

    2012-01-01

    制作了微型整体柱型的固定化酶反应器.在500μm内径毛细管内,以乙烯基三甲氧基硅烷处理形成端基烯键,采用原位合成法,以甲基丙烯酸2-羟乙酯为功能单体,以乙二醇二甲基丙烯酸酯为交联剂制备了整体柱.整体柱表面的羟基经NaIO4氧化形成醛基后与胰蛋白酶的氨基进一步反应,实现胰蛋白酶的固定.在24s内,该酶反应器实现了肌红蛋白和细胞色素c的酶解,经MALDI-TOF MS鉴定,序列覆盖率分别达到65%和79%.%A monolithic enzymatic microreactor was prepared in a 500 μm fused-silica capillary by in situ polymerization of 2-hydroxyethyl methacrylate (HEMA) and ethylene dimethacrylate (EDMA) in the presence of a binary porogenic mixture of 1-decanol and cyclohexanol, followed by sodium periodate treatment and trypsin modification. The excellent performance of the monolithic microreactor was also demonstrated with the digestion of myoglobin and cytochrome c at the fast flow rate of 15 μL/min, which afforded a residence time of only 24 s. The digest was then characterized using MALDI-TOFMS, and the sequence coverage were 65% and 79%.

  16. On the dynamics of immobilized enzyme kinetics in a microreactor: A study of AP-catalyzed reactions

    Directory of Open Access Journals (Sweden)

    Pratap R Patnaik

    2011-11-01

    Full Text Available Normal 0 false false false EN-US X-NONE X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin-top:0in; mso-para-margin-right:0in; mso-para-margin-bottom:10.0pt; mso-para-margin-left:0in; line-height:115%; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;} The kinetics of immobilized enzyme-catalyzed reactions in microreactors differ from those in macro-scale reactors. Recognizing this, a recent study (Patnaik 2011 based on a new interpretation of the kinetics of AP-catalyzed reactions showed that dynamic behavior is feasible only certain loci relating key kinetic parameters. That work has been extended here, and the kinetic parameters have now been related to bulk phase concentrations, thereby providing a link with the reaction system per se. It has also been shown that under certain conditions the reaction may become self-quenching but either monotonically or as damped oscillations. These two studies thus establish the importance of understanding kinetic dynamics in microreactors and in selecting feasible operating conditions.

  17. Modelling of retention of pesticides in reversed-phase high-performance liquid chromatography: Quantitative structure-retention relationships based on solute quantum-chemical descriptors and experimental (solvatochromic and spin-probe) mobile phase descriptors

    International Nuclear Information System (INIS)

    A quantitative structure-retention relationship (QSRR) analysis based on multilinear regression (MLR) and artificial neural networks (ANNs) is carried out to model the combined effect of solute structure and eluent composition on the retention behaviour of pesticides in isocratic reversed-phase high-performance liquid chromatography (RP-HPLC). The octanol-water partition coefficient and four quantum chemical descriptors (the total dipole moment, the mean polarizability, the anisotropy of the polarizability and a descriptor of hydrogen-bonding based on the atomic charges on acidic and basic chemical functionalities) are considered as solute descriptors. In order to identify suitable mobile phase descriptors, encoding composition-dependent properties of both methanol- and acetonitrile-containing mobile phases, the Kamlet-Taft solvatochromic parameters (polarity-dipolarity, hydrogen-bond acidity and hydrogen-bond basicity, π *, α and β, respectively) and the 14N hyperfine-splitting constant (a N) of a spin-probe dissolved in the eluent are examined. A satisfactory description of mobile phase properties influencing the solute retention is provided by a N and β or alternatively π * and β. The two seven-parameter models resulting from combination of a N and β, or π * and β, with the solute descriptors were tested on a set of 26 pesticides representative of 10 different chemical classes in a wide range of mobile phase composition (30-60% (v/v) water-methanol and 30-70% (v/v) water-acetonitrile). Within the explored experimental range, the acidity of the eluent, as quantified by α, is almost constant, and this parameter is in fact irrelevant. The results reveal that a N and π *, that can be considered as interchangeable mobile phase descriptors, are the most influent variables in the respective models. The predictive ability of the proposed models, as tested on an external data set, is quite good (Q 2 close to 0.94) when a MLR approach is used, but the modelling

  18. Reversible arithmetic logic unit

    OpenAIRE

    zhou, Rigui; Shi, Yang; Zhang, Manqun

    2011-01-01

    Quantum computer requires quantum arithmetic. The sophisticated design of a reversible arithmetic logic unit (reversible ALU) for quantum arithmetic has been investigated in this letter. We provide explicit construction of reversible ALU effecting basic arithmetic operations. By provided the corresponding control unit, the proposed reversible ALU can combine the classical arithmetic and logic operation in a reversible integrated system. This letter provides actual evidence to prove the possib...

  19. Size-controlled synthesis of ZrO2-TiO2 nanoparticles prepared via reverse micelle method

    International Nuclear Information System (INIS)

    Zirconium-titanium mixed oxide nanoparticles have been synthesized using microreactors made of bis-(2-ethylhexyl) sulfosuccinate (AOT)/water/n-hexane microemulsions. The control of particle size was achieved by varying the process variables, such as water-to-surfactant molar ratio and reagent concentration. Their sizes, appearances, crystal structures, pore diameter and surface area were characterized by TEM, XRD, N2 adsorption/desorption methods. The results revealed that samples prepared in reverse micelles had no crystalline phase. The Beckmann rearrangement of cyclohexanone oxime on ZrO2-TiO2 nanoparticles was carried out in a fixed-bed down flow reactor to investigate the effect of particle size on catalytic activity and selectivity. Samples synthesized in reverse micelles had better reaction performance than samples prepared via sol-gel method. A parallel relationship could be drawn between the catalytic activity and the particle size as well as the selectivity of the catalyst

  20. Structural Optimization Design and Simulation of Microreactor%微反应器的结构优化设计与仿真

    Institute of Scientific and Technical Information of China (English)

    陈雪叶; 佘东生; 魏兴; 杨金成

    2013-01-01

    A two-step microreactor was designed,and the influence of geometry parameters on reaction was optimized.To improve hybrid in the mix channel of the microreactor,the rib obstacles that can induce chaotic convection were designed.The ratio of height of obstacle and channel,the ratio of width of obstacle and spacing,and the width of obstacle were optimized with the software based on finite element theory.The serpentine channel was chose as the reaction unit of the microreactor,and the influences of the channel length,reaction time and initial concentration on reaction were investigated.Furthermore,a two-step microreactor for oxidation of glucose was designed.%设计了两步微反应器,对影响反应的几何参数进行了优化.对于微反应器的混合单元,设计了内肋型障碍物结构,用于产生混沌对流,促进样品混合.利用基于有限元原理的数值模拟软件分别对混合单元的障碍物与微通道的高宽比、障碍物宽度与间距的比值和障碍物的宽度进行设计与优化.采用蜿蜒通道作为微反应器的反应单元,研究了反应单元长度、反应时间与初始浓度对反应的影响.以葡萄糖氧化反应为例,设计了一个两步微反应器.

  1. Equilibrium Chemical Engines

    OpenAIRE

    Shibata, Tatsuo; Sasa, Shin-ichi

    1997-01-01

    An equilibrium reversible cycle with a certain engine to transduce the energy of any chemical reaction into mechanical energy is proposed. The efficiency for chemical energy transduction is also defined so as to be compared with Carnot efficiency. Relevance to the study of protein motors is discussed. KEYWORDS: Chemical thermodynamics, Engine, Efficiency, Molecular machine.

  2. Novel synthesis of thick wall coatings of titania supported Bi poisoned Pd catalysts and application in selective hydrogenation of acetylene alcohols in capillary microreactors.

    Science.gov (United States)

    Cherkasov, Nikolay; Ibhadon, Alex O; Rebrov, Evgeny V

    2015-04-21

    Catalysis in microreactors allows reactions to be performed in a very small volume, reducing the environmental problems and greatly intensifying the processes through easy pressure control and the elimination of heat- and mass-transfer limitations. In this study, we report a novel method for the controlled synthesis of micrometre-thick mesoporous TiO2 catalytic coatings on the walls of long channels (>1 m) of capillary microreactors in a single deposition step. The method uses elevated temperature and introduces a convenient control parameter of the deposition rate (displacement speed controlled by a stepper motor), which allows deposition from concentrated and viscous sols without channel clogging. A capillary microreactor wall-coated with titania supported Bi-poisoned Pd catalyst was obtained using the method and used for the semihydrogenation of 2-methyl-3-butyn-2-ol providing 93 ± 1.5% alkene yield for 100 h without deactivation. Although the coating method was applied only for TiO2 deposition, it is nonetheless suitable for the deposition of volatile sols. PMID:25749619

  3. A ceramic microreactor for the synthesis of water soluble CdS and CdS/ZnS nanocrystals with on-line optical characterization

    Science.gov (United States)

    Pedro, Sara Gómez-De; Puyol, Mar; Izquierdo, David; Salinas, Iñigo; de La Fuente, J. M.; Alonso-Chamarro, Julián

    2012-02-01

    In this paper, a computer controlled microreactor to synthesize water soluble CdS and CdS/ZnS nanocrystals with in situ monitoring of the reaction progress is developed. It is based on ceramic tapes and the Low-Temperature Co-fired Ceramics technology (LTCC). As well the microsystem set-up, the microreactor fluidic design has also been thoroughly optimized. The final device is based on a hydrodynamic focusing of the reagents followed by a three-dimensional micromixer. This generates monodispersed and stable CdS and core-shell CdS/ZnS nanocrystals of 4.5 and 4.2 nm, respectively, with reproducible optical properties in terms of fluorescence emission wavelengths, bandwidth, and quantum yields, which is a key requirement for their future analytical applications. The synthetic process is also controlled in real time with the integration of an optical detection system for absorbance and fluorescence measurements based on commercial miniaturized optical components. This makes possible the efficient managing of the hydrodynamic variables to obtain the desired colloidal suspension. As a result, a simple, economic, robust and portable microsystem for the well controlled synthesis of CdS and CdS/ZnS nanocrystals is presented. Moreover, the reaction takes place in aqueous medium, thus allowing the direct modular integration of this microreactor in specific analytical microsystems, which require the use of such quantum dots as labels.

  4. Externally controlled pressure and temperature microreactor for in situ x-ray diffraction, visual and spectroscopic reaction investigations under supercritical and subcritical conditions

    International Nuclear Information System (INIS)

    A microreactor has been developed for in situ, spectroscopic investigations of materials and reaction processes with full external pressure and temperature control from ambient conditions to 400 deg. C and 310 bar. The sample chamber is in direct contact with an external manifold, whereby gases, liquids or fluids can be injected and their activities controlled prior to and under investigation conditions. The microreactor employs high strength, single crystal moissanite windows which allow direct probe beam interaction with a sample to investigate in situ reaction processes and other materials properties. The relatively large volume of the cell, along with full optical accessibility and external temperature and pressure control, make this reaction cell well suited for experimental investigations involving any combination of gas, fluid, and solid interactions. The microreactor's capabilities are demonstrated through an in situ x-ray diffraction study of the conversion of a meta-serpentine sample to magnesite under high pressure and temperature. Serpentine is one of the mineral candidates for the implementation of mineral carbonation, an intriguing carbon sequestration candidate technology

  5. Reverse Shoulder Arthroplasty

    Medline Plus

    Full Text Available ... you can use for reverse shoulder replacement. The standard delto-pectoral approach, or the superior approach, which ... that are different between a reverse and a standard total is, first of all, we don't ...

  6. Reverse Shoulder Arthroplasty

    Medline Plus

    Full Text Available ... the height perfectly to get anatomic head tuberosity relationships. If you're doing a reverse for a ... less limited with the superior reverse versus the traditional. And I assume the question means the approach: ...

  7. Reverse cholesterol transport revisited

    Institute of Scientific and Technical Information of China (English)

    Astrid; E; van; der; Velde

    2010-01-01

    Reverse cholesterol transport was originally described as the high-density lipoprotein-mediated cholesterol flux from the periphery via the hepatobiliary tract to the intestinal lumen, leading to fecal excretion. Since the introduction of reverse cholesterol transport in the 1970s, this pathway has been intensively investigated. In this topic highlight, the classical reverse cholesterol transport concepts are discussed and the subject reverse cholesterol transport is revisited.

  8. 铜离子掺杂二氧化钛光催化板式微反应器%Photocatalytic planar microreactor of copper ion doped titanium dioxide

    Institute of Scientific and Technical Information of China (English)

    林骋; 刘明言

    2014-01-01

    Applying microreactor technology to photocatalytic reactions is a novel and potential technical innovation. Photocatalytic planar microreactors were fabricated by metal etching technology, and copper ion doped TiO2 was immobilized as coatings by the sol-gel method. X-ray diffraction, scanning electron microscope and UV-visible diffuse reflection were used for characterization of photocatalyst. The microreactors were tested for the degradation of methyl orange and the optimal doping concentration of copper ion was found to be 0.04% (mole ratio to Ti). The degradation ratio of methyl orange with an initial concentration of 10 mg·L-1 could reach 45% within 90 s in the microreactor. Degradation ratios of methyl orange in microreactors under controlled irradiation were measured, and the copper ion doped photocatalytic microreactors showed better utilization of irradiation energy. The study of kinetics illustrated that the degradation of methyl orange in the microreactors was a first order reaction of incomplete oxidation with a much greater rate constant (k) comparing to regular reactors. The rate constant increased with the decreasing of initial concentration (C0), and there was a good linear relationship of lnk and lnC0.%将微反应器技术应用于光催化反应是一项新兴且极具潜力的技术创新。采用金属蚀刻技术制造了板式微反应器,并通过溶胶-凝胶法在微反应器中负载了铜离子掺杂改性的TiO2光催化剂涂层。使用X射线衍射分析、扫描电子显微镜以及紫外-可见漫反射吸收光谱对催化剂进行表征,并以甲基橙的降解反应来评价微反应器的光催化效果。结果表明,铜离子掺杂能够有效提高微反应器的光催化性能,掺杂浓度为0.04%(摩尔比于Ti)时效果最优,能够在90 s的停留时间内使初始浓度为10 mg·L-1的甲基橙溶液降解45%;光催化微反应器中甲基橙的降解过程为不完全氧化的动力学一级反应,

  9. The Inherent Reactor Kinetics for Transformation of Geniposidic Acid from Geniposide in a Microreactor

    OpenAIRE

    Chiu-Lan Hsieh; Wang-Chi Hsieh

    2015-01-01

    The ripe fruits of Gardenia jasminoides Ellis (Rubiaceae) (GJ) are widely used in chemical, food and medicinal industries. Crocin and geniposide, the main constituents of GJ, have shown a diversity of biological activities including sedative, anti-inflammatory and antipyretic. We propose some new bioactive chemicals could be derived from geniposide. The optimum transformation condition of geniposide into geniposidic acid still remains unclear. In order to develop a reactor, the in...

  10. Continuous Hydrogenation of 2-Methylpropene on Pt Catalyst in the Microreactor for Kinetic Studies

    Czech Academy of Sciences Publication Activity Database

    Vajglová, Z.; Stavárek, Petr; Křišťál, Jiří; Kolena, J.; Jiřičný, Vladimír

    - : -, 2013, -. ISBN N. [European Congress of Chemical Engineering /9./. The Hague (NL), 21.04.2013-25.04.2013] Grant ostatní: GA MŠk(CZ) MŠMT:CZ.1.05/2.1.00/03.0071 Institutional support: RVO:67985858 Keywords : heterogeneous catalysis * microeractor * kinetic studies Subject RIV: CI - Industrial Chemistry, Chemical Engineering http://www.ecce2013.eu/index.php

  11. An Inert Continuous Microreactor for the Isolation and Analysis of a Single Microbial Cell

    OpenAIRE

    Katrin Rosenthal; Floris Falke; Oliver Frick; Christian Dusny; Andreas Schmid

    2015-01-01

    Studying biological phenomena of individual cells is enabled by matching the scales of microbes and cultivation devices. We present a versatile, chemically inert microfluidic lab-on-a-chip (LOC) device for biological and chemical analyses of isolated microorganisms. It is based on the Envirostat concept and guarantees constant environmental conditions. A new manufacturing process for direct fusion bonding chips with functional microelectrodes for selective and gentle cell manipulation via neg...

  12. Rotating Reverse-Osmosis for Water Purification

    Science.gov (United States)

    Lueptow, RIchard M.

    2004-01-01

    A new design for a water-filtering device combines rotating filtration with reverse osmosis to create a rotating reverse- osmosis system. Rotating filtration has been used for separating plasma from whole blood, while reverse osmosis has been used in purification of water and in some chemical processes. Reverse- osmosis membranes are vulnerable to concentration polarization a type of fouling in which the chemicals meant not to pass through the reverse-osmosis membranes accumulate very near the surfaces of the membranes. The combination of rotating filtration and reverse osmosis is intended to prevent concentration polarization and thereby increase the desired flux of filtered water while decreasing the likelihood of passage of undesired chemical species through the filter. Devices based on this concept could be useful in a variety of commercial applications, including purification and desalination of drinking water, purification of pharmaceutical process water, treatment of household and industrial wastewater, and treatment of industrial process water. A rotating filter consists of a cylindrical porous microfilter rotating within a stationary concentric cylindrical outer shell (see figure). The aqueous suspension enters one end of the annulus between the inner and outer cylinders. Filtrate passes through the rotating cylindrical microfilter and is removed via a hollow shaft. The concentrated suspension is removed at the end of the annulus opposite the end where the suspension entered.

  13. An Inert Continuous Microreactor for the Isolation and Analysis of a Single Microbial Cell

    Directory of Open Access Journals (Sweden)

    Katrin Rosenthal

    2015-11-01

    Full Text Available Studying biological phenomena of individual cells is enabled by matching the scales of microbes and cultivation devices. We present a versatile, chemically inert microfluidic lab-on-a-chip (LOC device for biological and chemical analyses of isolated microorganisms. It is based on the Envirostat concept and guarantees constant environmental conditions. A new manufacturing process for direct fusion bonding chips with functional microelectrodes for selective and gentle cell manipulation via negative dielectrophoresis (nDEP was generated. The resulting LOC system offered a defined surface chemistry and exceptional operational stability, maintaining its structural integrity even after harsh chemical treatment. The microelectrode structures remained fully functional after thermal bonding and were proven to be efficient for single-cell trapping via nDEP. The microfluidic network consisted solely of glass, which led to enhanced chip reusability and minimized interaction of the material with chemical and biological compounds. We validated the LOC for single-cell studies with the amino acid secreting bacterium Corynebacterium glutamicum. Intracellular l-lysine production dynamics of individual bacteria were monitored based on a genetically encoded fluorescent nanosensor. The results demonstrate the applicability of the presented LOC for pioneering chemical and biological studies, where robustness and chemically inert surfaces are crucial parameters for approaching fundamental biological questions at a single-cell level.

  14. Diamondoid synthesis in atmospheric pressure adamantane-argon-methane-hydrogen mixtures using a continuous flow plasma microreactor

    Science.gov (United States)

    Stauss, Sven; Ishii, Chikako; Pai, David Z.; Urabe, Keiichiro; Terashima, Kazuo

    2014-06-01

    Due to their small size, low-power consumption and potential for integration with other devices, microplasmas have been used increasingly for the synthesis of nanomaterials. Here, we have investigated the possibility of using dielectric barrier discharges generated in continuous flow glass microreactors for the synthesis of diamondoids, at temperatures of 300 and 320 K, and applied voltages of 3.2-4.3 kVp-p, at a frequency of 10 kHz. The microplasmas were generated in gas mixtures containing argon, methane, hydrogen and adamantane, which was used as a precursor and seed. The plasmas were monitored by optical emission spectroscopy measurements and the synthesized products were characterized by gas chromatography—mass spectrometry (GC-MS). Depending on the gas composition, the optical emission spectra contained CH and C2 bands of varying intensities. The GC-MS measurements revealed that diamantane can be synthesized by microplasmas generated at atmospheric pressure, and that the yields highly depend on the gas composition and the presence of carbon sources.

  15. Enzymatic Catalysis Combining the Breath Figures and Layer-by-Layer Techniques: Toward the Design of Microreactors.

    Science.gov (United States)

    De León, A S; Garnier, T; Jierry, L; Boulmedais, F; Muñoz-Bonilla, A; Rodríguez-Hernández, J

    2015-06-10

    Herein, we report the fabrication of microstructured porous surfaces with controlled enzymatic activity by combining the breath figures and the layer-by-layer techniques. Two different types of porous surfaces were designed based on fluorinated and carboxylated copolymers in combination with PS, using poly(2,3,4,5,6-pentafluorostyrene)-b-polystyrene (PS5F31-b-PS21) and polystyrene-b-poly(acrylic acid) (PS19-b-PAA10) block copolymers, respectively. For comparative purposes, flat surfaces having similar chemistry were obtained by spin-coating. Poly(sodium 4-styrenesulfonate)/poly(allylamine hydrochloride) (PSS/PAH) multilayers incorporating alkaline phosphatase (ALP) were built on these porous surfaces to localize the enzyme both inside and outside of the pores using PS/PS5F31-b-PS21 surfaces and only inside the pores on PS/PS19-b-PAA10 surfaces. A higher catalytic activity of ALP (about three times) was obtained with porous surfaces compared to the flat ones. The catalysis happens specifically inside the holes of PS/PS19-b-PAA10surfaces, where ALP is located. This opens the route for applications in microreactors. PMID:25984795

  16. On-line coupling of immobilized cytochrome P450 microreactor and capillary electrophoresis: A promising tool for drug development.

    Science.gov (United States)

    Schejbal, Jan; Řemínek, Roman; Zeman, Lukáš; Mádr, Aleš; Glatz, Zdeněk

    2016-03-11

    In this work, the combination of an immobilized enzyme microreactor (IMER) based on the clinically important isoform cytochrome P450 2C9 (CYP2C9) with capillary electrophoresis (CE) is presented. The CYP2C9 was attached to magnetic SiMAG-carboxyl microparticles using the carbodiimide method. The formation of an IMER in the inlet part of the separation capillary was ensured by two permanent magnets fixed in a cassette from the CE apparatus in the repulsive arrangement. The resulting on-line system provides an integration of enzyme reaction mixing and incubation, reaction products separation, detection and quantification into a single fully automated procedure with the possibility of repetitive use of the enzyme and minuscule amounts of reactant consumption. The on-line kinetic and inhibition studies of CYP2C9's reaction with diclofenac as a model substrate and sulfaphenazole as a model inhibitor were conducted in order to demonstrate its practical applicability. Values of the apparent Michalis-Menten constant, apparent maximum reaction velocity, Hill coefficient, apparent inhibition constant and half-maximal inhibition concentration were determined on the basis of the calculation of the effective substrate and inhibitor concentrations inside the capillary IMER using a model described by the Hagen-Poisseulle law and a novel enhanced model that reflects the influence of the reactants' diffusion during the injection process. PMID:26877175

  17. Design of Reversible Counter

    OpenAIRE

    Md. Selim Al Mamun; B. K. Karmaker

    2014-01-01

    This article presents a research work on the design and synthesis of sequential circuits and flip-flops that are available in digital arena; and describes a new synthesis design of reversible counter that is optimized in terms of quantum cost, delay and garbage outputs compared to the existing designs. We proposed a new model of reversible T flip-flop in designing reversible counter.

  18. "Reverse" Nested Lottery Contests

    OpenAIRE

    Qiang Fu; Jingfeng Lu; Zhewei Wang

    2013-01-01

    This paper proposes a multi-prize "reverse" nested lottery contest model, which can be viewed as the "mirror image" of the conventional nested lottery contest of Clark and Riis (1996a). The reverse-lottery contest model determines winners by selecting losers based on contestants' one-shot effort through a hypothetical sequence of lotteries. We provide a microfoundation for the reverse-lottery contest from a perspective of (simultaneous) noisy performance ranking and establish that the model i...

  19. Posterior Reversible Encephalopathy Syndrome

    OpenAIRE

    J Gordon Millichap

    2013-01-01

    Investigators at Children's Hospital of Montefiore, Albert Einstein College of Medicine, NY, determined the incidence of posterior reversible encephalopathy syndrome (PRES) in a pediatric critical care unit.

  20. Photochemical synthesis of a "cage" compound in a microreactor: Rigorous comparison with a batch photoreactor

    OpenAIRE

    Aillet, Tristan; Loubiere, Karine; Dechy-Cabaret, Odile; Prat, Laurent E.

    2013-01-01

    International audience An intramolecular [2 + 2] photocycloaddition is performed in a microphotoreactor (0.81 mL) built by winding FEP tubing around a commercially available Pyrex immersion well in which a medium pressure mercury lamp is inserted. A rigorous comparison with a batch photoreactor (225 mL) is proposed by means of a simple model coupling the reaction kinetics with the mass, momentum and radiative transfer equations. This serves as a basis to explain why the chemical conversion...

  1. Pursuit-and-Evasion Reaction-Diffusion Waves in Microreactors with Tailored Geometry.

    Science.gov (United States)

    Zambrano, A; Zadorin, A S; Rondelez, Y; Estévez-Torres, A; Galas, J-C

    2015-04-30

    Out-of-equilibrium chemical systems may self-organize into structures displaying spatiotemporal order, such as traveling waves and Turing patterns. Because of its predictable chemistry, DNA has recently appeared as an interesting candidate to engineer these spatiotemporal structures. However, in addition to the intrinsic chemical parameters, initial and boundary conditions have a major impact on the final structure. Here we take advantage of microfluidics to design controlled reactors and investigate pursuit-and-evasion chemical waves generated by a DNA-based reaction network with Predator-Prey dynamics. We first propose two complementary microfabrication strategies to either control the initial condition or the two-dimensional geometry of the reactor where the waves develop. We subsequently use them to investigate the effect of curvature in wave propagation. We finally show that DNA-based waves can compute the optimal path within a maze. We thus suggest that coupling configurable microfluidics to programmable DNA-based dissipative reaction networks is a powerful route to investigate spatiotemporal order formation in chemistry. PMID:25839240

  2. Visible Light Driven Photocascade Catalysis: Ru(bpy)3(PF6)2/TBHP-Mediated Synthesis of Fused β-Carbolines in Batch and Flow Microreactors.

    Science.gov (United States)

    Chandrasekhar, D; Borra, Satheesh; Nanubolu, Jagadeesh Babu; Maurya, Ram Awatar

    2016-06-17

    1,2,3,4-Tetrahydro-β-carbolines were coupled with α-keto vinyl azides through an unprecedented visible light-Ru(bpy)3(PF6)2/TBHP mediated photocascade strategy that involves photosensitization, photoredox catalysis and [3 + 2] cycloaddition reaction. The scope and scale-up feasibility of the photocascade strategy was demonstrated by synthesizing 18 different fused β-carbolines in moderate to good yields using batch and continuous flow microreactor. This operationally simple synthetic protocol allows the formation of one C-C and two C-N new bonds in the overall transformation. PMID:27226119

  3. Axial Changes of Catalyst Structure and Temperature in a Fixed-Bed Microreactor During Noble Metal Catalysed Partial Oxidation of Methane

    DEFF Research Database (Denmark)

    Hannemann, S.; Grunwaldt, Jan-Dierk; Kimmerle, B.;

    2009-01-01

    -line mass spectrometry. This experimental strategy allowed collecting data on the structure of the noble metal (oxidation state) and the temperature along the catalyst bed. The reaction was investigated in a fixed-bed quartz microreactor (1-1.5 mm diameter) following the catalytic performance by on-line gas...... exothermic methane oxidation was too strong. The results indicate that in the oxidized zone mainly combustion of methane occurs, whereas in the reduced part direct partial oxidation and reforming reactions prevail. The results demonstrate how spatially resolved spectroscopy can help in understanding...

  4. Oxidation of CO and H2 by O2 and N2O on Au/TiO2 catalysts in microreactors

    DEFF Research Database (Denmark)

    Walther, Guido; Mowbray, Duncan; Jiang, Tao; Jones, Glenn; Jensen, Søren; Quaade, Ulrich; Horch, Sebastian

    2008-01-01

    We performed steady-state activity measurements in microreactors to obtain the reaction rates for CO and H2 oxidation. These reactions were studied on three different gold particle sizes (d≈3.6,5.7,16.2 nm) using either O2 or N2O as oxidizing agents. From our TEM analysis, our CO oxidation rates...... activation barriers of about 37 kJ mol−1 for CO oxidation on the smallest nanoparticles by both O2 and N2O. For all of the reactions studied, we found the overall activation barrier depended only on the size of the TiO2 supported gold nanoparticle....

  5. Reversible cerebral vasoconstriction syndrome

    Directory of Open Access Journals (Sweden)

    Saini Monica

    2009-01-01

    Full Text Available Reversible cerebral vasoconstriction syndromes (RCVS are a group of disorders that have in common an acute presentation with headache, reversible vasoconstriction of cerebral arteries, with or without neurological signs and symptoms. In contrast to primary central nervous system vasculitis, they have a relatively benign course. We describe here a patient who was diagnosed with RCVS.

  6. Quantum reverse hypercontractivity

    Energy Technology Data Exchange (ETDEWEB)

    Cubitt, Toby [Department of Computer Science, University College London, London, United Kingdom and Centre for Quantum Information and Foundations, DAMTP, University of Cambridge, Cambridge (United Kingdom); Kastoryano, Michael [NBIA, Niels Bohr Institute, University of Copenhagen, 2100 Copenhagen (Denmark); Montanaro, Ashley [School of Mathematics, University of Bristol, Bristol (United Kingdom); Temme, Kristan [Institute for Quantum Information and Matter, California Institute of Technology, Pasadena, California 91125 (United States)

    2015-10-15

    We develop reverse versions of hypercontractive inequalities for quantum channels. By generalizing classical techniques, we prove a reverse hypercontractive inequality for tensor products of qubit depolarizing channels. We apply this to obtain a rapid mixing result for depolarizing noise applied to large subspaces and to prove bounds on a quantum generalization of non-interactive correlation distillation.

  7. Preparation of nanoparticles in reverse microemulsions

    Science.gov (United States)

    Tovstun, Sergey A.; Razumov, Vladimir F.

    2011-10-01

    Experimental data and results of theoretical studies dealing with the synthesis of nanoparticles by the condensation of products of chemical reactions in reverse microemulsions are generalized. Attention is focused on the analysis of mechanisms of nanoparticle nucleation and growth. The bibliography includes 252 references.

  8. Long-term real-time monitoring catalytic synthesis of ammonia in a microreactor by VUV-lamp-based charge-transfer ionization time-of-flight mass spectrometry.

    Science.gov (United States)

    Xie, Yuanyuan; Hua, Lei; Hou, Keyong; Chen, Ping; Zhao, Wuduo; Chen, Wendong; Ju, Bangyu; Li, Haiyang

    2014-08-01

    With respect to massive consumption of ammonia and rigorous industrial synthesis conditions, many studies have been devoted to investigating more environmentally benign catalysts for ammonia synthesis under moderate conditions. However, traditional methods for analysis of synthesized ammonia (e.g., off-line ion chromatography (IC) and chemical titration) suffer from poor sensitivity, low time resolution, and sample manipulations. In this work, charge-transfer ionization (CTI) with O2(+) as the reagent ion based on a vacuum ultraviolet (VUV) lamp in a time-of-flight mass spectrometer (CTI-TOFMS) has been applied for real-time monitoring of the ammonia synthesis in a microreactor. For the necessity of long-term stable monitoring, a self-adjustment algorithm for stabilizing O2(+) ion intensity was developed to automatically compensate the attenuation of the O2(+) ion yield in the ion source as a result of the oxidation of the photoelectric electrode and contamination on the MgF2 window of the VUV lamp. A wide linear calibration curve in the concentration range of 0.2-1000 ppmv with a correlation coefficient (R(2)) of 0.9986 was achieved, and the limit of quantification (LOQ) for NH3 was in ppbv. Microcatalytic synthesis of ammonia with three catalysts prepared by transition-metal/carbon nanotubes was tested, and the rapid changes of NH3 conversion rates with the reaction temperatures were quantitatively measured with a time resolution of 30 s. The high-time-resolution CTI-TOFMS could not only achieve the equilibrium conversion rates of NH3 rapidly but also monitor the activity variations with respect to investigated catalysts during ammonia synthesis reactions. PMID:24968116

  9. Open tubular capillary electrochromatography: A useful microreactor for collagen I glycation and interaction studies with low-density lipoprotein particles

    Energy Technology Data Exchange (ETDEWEB)

    D' Ulivo, Lucia; Witos, Joanna [Laboratory of Analytical Chemistry, Department of Chemistry, P.O. Box 55, FIN-00014 University of Helsinki (Finland); Ooerni, Katariina; Kovanen, Petri T. [Wihuri Research Institute, Kalliolinnantie 4, FIN-00140, Helsinki (Finland); Riekkola, Marja-Liisa, E-mail: marja-liisa.riekkola@helsinki.fi [Laboratory of Analytical Chemistry, Department of Chemistry, P.O. Box 55, FIN-00014 University of Helsinki (Finland)

    2010-04-07

    Diabetes, a multifunctional disease and a major cause of morbidity and mortality in the industrialized countries, strongly associates with the development and progression of atherosclerosis. One of the consequences of high level of glucose in the blood circulation is glycation of long-lived proteins, such as collagen I, the most abundant component of the extracellular matrix (ECM) in the arterial wall. Glycation is a long-lasting process that involves the reaction between a carbonyl group of the sugar and an amino group of the protein, usually a lysine residue. This reaction generates an Amadori product that may evolve in advanced glycation end products (AGEs). AGEs, as reactive molecules, can provoke cross-linking of collagen I fibrils. Since binding of low-density lipoproteins (LDLs) to the ECM of the inner layer of the arterial wall, the intima, has been implicated to be involved in the onset of the development of an atherosclerotic plaque, collagen modifications, which can affect the affinity of native and oxidized LDL for collagen I, can promote the entrapment of LDLs in the intima and accelerate the progression of atherosclerosis. In this study, open tubular capillary electrochromatography is proposed as a new microreactor to study in situ glycation of collagen I. The kinetics of glycation was first investigated in a fused silica collagen I-coated capillary. Dimethyl sulphoxide, injected as an electroosmotic flow marker, gave information about the charge of coating. Native and oxidized LDL, and selected peptide fragments from apolipoprotein B-100, the protein covering LDL particles, were injected as marker compounds to clarify the interactions between LDLs and the glycated collagen I coating. The method proposed is simple and inexpensive, since only small amounts of collagen and LDL are required. Atomic force microscopy images complemented our studies, highlighting the difference between unmodified and glycated collagen I surfaces.

  10. Reverse Engineering Adverse Outcome Pathways

    Energy Technology Data Exchange (ETDEWEB)

    Perkins, Edward; Chipman, J.K.; Edwards, Stephen; Habib, Tanwir; Falciani, Francesco; Taylor, Ronald C.; Van Aggelen, Graham; Vulpe, Chris; Antczak, Philipp; Loguinov, Alexandre

    2011-01-30

    The toxicological effects of many stressors are mediated through unknown, or poorly characterized, mechanisms of action. We describe the application of reverse engineering complex interaction networks from high dimensional omics data (gene, protein, metabolic, signaling) to characterize adverse outcome pathways (AOPs) for chemicals that disrupt the hypothalamus-pituitary-gonadal endocrine axis in fathead minnows. Gene expression changes in fathead minnow ovaries in response to 7 different chemicals, over different times, doses, and in vivo versus in vitro conditions were captured in a large data set of 868 arrays. We examined potential AOPs of the antiandrogen flutamide using two mutual information theory methods, ARACNE and CLR to infer gene regulatory networks and potential adverse outcome pathways. Representative networks from these studies were used to predict a network path from stressor to adverse outcome as a candidate AOP. The relationship of individual chemicals to an adverse outcome can be determined by following perturbations through the network in response to chemical treatment leading to the nodes associated with the adverse outcome. Identification of candidate pathways allows for formation of testable hypotheses about key biologic processes, biomarkers or alternative endpoints, which could be used to monitor an adverse outcome pathway. Finally, we identify the unique challenges facing the application of this approach in ecotoxicology, and attempt to provide a road map for the utilization of these tools. Key Words: mechanism of action, toxicology, microarray, network inference

  11. An Algebra of Reversible Computation

    OpenAIRE

    Wang, Yong

    2014-01-01

    We design an axiomatization for reversible computation called reversible ACP (RACP). It has four extendible modules, basic reversible processes algebra (BRPA), algebra of reversible communicating processes (ARCP), recursion and abstraction. Just like process algebra ACP in classical computing, RACP can be treated as an axiomatization foundation for reversible computation.

  12. Vertical Microreactor Stack Consist of Poly-(Tetrafluoroethylene) Microfluidics for Immunoassay

    Science.gov (United States)

    Ukita, Yoshiaki; Kondo, Saki; Takeo, Masahiro; Negoro, Seiji; Kataoka, Chiwa; Utsumi, Yuichi

    This paper reports the first application of high-aspect ratio PTFE microstruscute, which fabricated by synchrotron radiation induced photo-evaporation process, to enzyme-linked immunosorvent assay. The advantages of PTFE microstructure for the development of lab-on-a-chip due to the extremely high-aspect ratio microstructure and chemical stability of PTFE is discussed. The results of immunoassay shows the successful detection of analyte (mouse IgG) with detection range with 0-100ng/ml. This result suggests the successful immobilization of antibody (anti-mouse IgG goat antibody) onto the x-ray exposed surface of PTFE microstructue and successful demonstration of antigen-antibody reaction in the PTFE high-aspect ratio microstructure. We also demonstrated the detection of polychlorinated biphenyl (PCB). As the result of demonstration, we successfully detected PCB with ranging analyte concentration of 0.1-10 ng/ml.

  13. Vertical microreactor stack consist of poly-(tetrafluoroethylene) microfluidics for immunoassay

    International Nuclear Information System (INIS)

    This paper reports the first application of high-aspect ratio PTFE microstruscute, which fabricated by synchrotron radiation induced photo-evaporation process, to enzyme-linked immunosorvent assay. The advantages of PTFE microstructure for the development of lab-on-a-chip due to the extremely high-aspect ratio microstructure and chemical stability of PTFE is discussed. The results of immunoassay shows the successful detection of analyte (mouse IgG) with detection range with 0-100ng/ml. This result suggests the successful immobilization of antibody (anti-mouse IgG goat antibody) onto the x-ray exposed surface of PTFE microstructure and successful demonstration of antigen-antibody reaction in the PTFE high-aspect ratio microstructure. We also demonstrated the detection of polychlorinated biphenyl (PCB). As the result of demonstration, we successfully detected PCB with ranging analyte concentration of 0.1-10 ng/ml. (author)

  14. On the construction of reversible automata for reversible languages

    OpenAIRE

    Lombardy, Sylvain

    2002-01-01

    International audience Reversible languages occur in many different domains. Although the decision for the membership of reversible languages was solved in 1992 by Pin, an effective construction of a reversible automaton for a reversible language was still unknown. We give in this paper a method to compute a reversible automaton from the minimal automaton of a reversible language. With this intention, we use the universal automaton of the language that can be obtained from the minimal auto...

  15. Reversible flowchart languages and the structured reversible program theorem

    DEFF Research Database (Denmark)

    Yokoyama, Tetsuo; Axelsen, Holger Bock; Glück, Robert

    2008-01-01

    Many irreversible computation models have reversible counterparts, but these are poorly understood at present. We introduce reversible flowcharts with an assertion operator and show that any reversible flowchart can be simulated by a structured reversible flowchart using only three control flow o...... justification for low-level machine code for reversible microprocessors as well as high-level block-structured reversible languages. We give examples for both such languages and illustrate them with a lossless encoder for permutations given by Dijkstra....

  16. Reverse Shoulder Arthroplasty

    Medline Plus

    Full Text Available ... stability and soft tissue envelope. In the early days of reverse arthroplasty, it used to be said ... often we'll drain these patients for a day to try to prevent hematoma formation, especially in ...

  17. Purchasing As Reverse Marketing

    OpenAIRE

    Blenkhorn, D L; Banting, P M

    1989-01-01

    This paper describes a new concept called reverse marketing, which is changing the conventional buyer-seller relationship and has important implications for the traditional role of the industrial marketer.

  18. Reverse Shoulder Arthroplasty

    Medline Plus

    Full Text Available ... replacement. There are two basic approaches you can use for reverse shoulder replacement. The standard delto-pectoral ... surgery or a deltoid defect because you can use the same incision and repair any deltoid defects ...

  19. Reverse Shoulder Arthroplasty

    Medline Plus

    Full Text Available ... the reverse allow patients to play tennis or sports where the arm swings backward. Our experience has ... who simply wants to be stronger or play sports better. But in terms of the patients that ...

  20. Reverse Shoulder Arthroplasty

    Medline Plus

    Full Text Available ... with an intact cuff, we would consider a traditional shoulder replacement. There are two basic approaches you ... less limited with the superior reverse versus the traditional. And I assume the question means the approach: ...

  1. Reverse Shoulder Arthroplasty

    Medline Plus

    Full Text Available ... in the United States. The indications are a patient with painful arthritis, absent rotator cuff, a less ... reverse arthroplasty is indicated for that type of patient. In a younger patient with an intact cuff, ...

  2. Reverse Shoulder Arthroplasty

    Medline Plus

    Full Text Available ... reverse shoulder arthroplasty for cuff deficient arthritis. You should be aware that I helped design the system ... the delto- pectoral approach. The three features you should watch for in this video are the things ...

  3. Reverse Shoulder Arthroplasty

    Medline Plus

    Full Text Available ... the height perfectly to get anatomic head tuberosity relationships. If you're doing a reverse for a ... able to start some gentle mobility of the body and the arm, and have better pain relief. ...

  4. Reverse Shoulder Arthroplasty

    Medline Plus

    Full Text Available ... a friction bite that if you try to work it around the corner, you can get an ... stability and soft tissue envelope. In the early days of reverse arthroplasty, it used to be said ...

  5. Reverse Shoulder Arthroplasty

    Medline Plus

    Full Text Available ... We usually lay this just at the inner table of the biceps groove next to the lesser ... is, does the reverse allow patients to play tennis or sports where the arm swings backward. Our ...

  6. Reverse Shoulder Arthroplasty

    Medline Plus

    Full Text Available ... is essentially a culture medium. So, I use antibiotic-impregnated cement when I do the reverses. I ... minimal. At our institution we keep them on antibiotics for 24 hours. And hopefully the drain output ...

  7. Reverse Shoulder Arthroplasty

    Medline Plus

    Full Text Available ... case of reverse shoulder arthroplasty for cuff deficient arthritis. You should be aware that I helped design ... in the last decade for cuff deficient shoulder arthritis in the United States. The indications are a ...

  8. Reverse Shoulder Arthroplasty

    Medline Plus

    Full Text Available ... dislocations, although it's also reported to have a higher rate of getting the components in not perfect ... about infection and other things. There is a higher rate of infection with reverse replacement, probably because ...

  9. Reverse Shoulder Arthroplasty

    Medline Plus

    Full Text Available ... here in New York to bring you a video of a recent case of reverse shoulder arthroplasty ... helped design the system that's shown in this video, so I receive royalties and therefore have a ...

  10. Reverse Shoulder Arthroplasty

    Medline Plus

    Full Text Available ... residents and do receive compensation for that, as well. Now, reverse shoulder arthroplasty is a new option ... t see the neck of the humerus as well, but on the other hand, you have a ...

  11. Reverse Shoulder Arthroplasty

    Medline Plus

    Full Text Available ... terminal range. The other thing to keep in mind is there's a fairly large dead space between ... the height perfectly to get anatomic head tuberosity relationships. If you're doing a reverse for a ...

  12. Reverse Shoulder Arthroplasty

    Medline Plus

    Full Text Available ... their arm up but they can't do it actively. And the reverse arthroplasty is indicated for ... those. The advantage of a superior approach is it's especially useful if you've had previous open ...

  13. Reversibility: An Engineer's Point of View

    International Nuclear Information System (INIS)

    Reversibility is the most consistent option in a democratic country. However reversibility may also have several drawbacks which must be identified and mitigated. Reversibility of a geological repository is a relatively new idea in France. The 1991 law dedicated to nuclear waste management considered reversibility as a possible option. Fifteen years later, the 2006 law mandated that a deep repository must be reversible and that the exact content of this notion should be defined by a new law to be discussed by the Parliament in 2015. Reversibility was not a concern put forward by engineers. It clearly originated from a societal demand sponsored and formulated by the Parliament. Since 1991, the exact meaning of this mandate progressively became more precise. In the early days, reversibility meant the technical and financial capability to retrieve the wastes from the repository, at least for some period of time after being emplaced. Progressively, a broader definition, suggested by Andra, was accepted: reversibility also means that a disposal facility should be operated in such a way that a stepwise decision-making process is possible. At each step, society must be able to decide to proceed to the next step, to pause or to reverse a step. Several benefits can be expected from a reversible repository. Some technical safety concerns may be only recognised after waste emplacement. Radioactive wastes may become a resource whose recoverability is desirable. Regulations may change, alternative waste treatment or better disposal techniques may be developed, or the need to modify a component of the facility may arise. Looking back at how chemical or domestic wastes were managed some 50 years ago easily underscores that it is not unreasonable to hope for significant advances in the future. For scientists and engineers, reversibility proves to have several other merits. To design and build a good repository, time is needed. The operator of a mine or of an oil field knows that

  14. Reverse vending machine update

    Energy Technology Data Exchange (ETDEWEB)

    Rypins, S.; Papke, C.

    1986-02-01

    The document discusses reverse vending machines. Placed outdoors in supermarket parking lots or indoors in the lobby of the grocery market, these hightech machines exchange aluminum cans (or other containers in more specialized machines) for cash, coupons or redeemable receipts. The placement of reverse venders (RV) in or near supermarkets has made recycling more visible and more convenient, although the machines have yet to fully reach industry goals.

  15. PROCESSING REVERSE LOGISTICS INVENTORIES

    OpenAIRE

    Bajor, Ivona; Novačko, Luka; Ogrizović, Dario

    2014-01-01

    Developed logistics systems have organized reverse logistics flows and are continuously analyzing product returns, tending to detect patterns in oscillations of returning products in certain time periods. Inventory management in reverse logistics systems depends on different criteria, regarding goods categories, formed contracts between subjects of supply chains, uncertainty in manufacturer’s quantities of DOA (dead on arrival) products, etc. The developing logistics systems, such as the Croa...

  16. Vasectomy reversal in humans

    OpenAIRE

    Bernie, Aaron M.; Osterberg, E Charles; Stahl, Peter J.; Ramasamy, Ranjith; Goldstein, Marc

    2012-01-01

    Vasectomy is the most common urological procedure in the United States with 18% of men having a vasectomy before age 45. A significant proportion of vasectomized men ultimately request vasectomy reversal, usually due to divorce and/or remarriage. Vasectomy reversal is a commonly practiced but technically demanding microsurgical procedure that restores patency of the male excurrent ductal system in 80–99.5% of cases and enables unassisted pregnancy in 40–80% of couples. The discrepancy between...

  17. Electroless plating of ultrathin palladium films: self-initiated deposition and application in microreactor fabrication

    Science.gov (United States)

    Muench, Falk; Oezaslan, Mehtap; Svoboda, Ingrid; Ensinger, Wolfgang

    2015-10-01

    We present new electroless palladium plating reactions, which can be applied to complex-shaped substrates and lead to homogeneous, dense and conformal palladium films consisting of small nanoparticles. Notably, autocatalytic and surface-selective metal deposition could be achieved on a wide range of materials without sensitization and activation pretreatments. This provides a facile and competitive route to directly deposit well-defined palladium nanofilms on e.g. carbon, paper, polymers or glass substrates. The reactions proceed at mild conditions and are based on easily accessible chemicals (reducing agent: hydrazine; metal source: PdCl2; ligands: ethylenediaminetetraacetic acid (EDTA), acetylacetone). Additionally, the water-soluble capping agent 4-dimethylaminopyridine (DMAP) is employed to increase the bath stability, to ensure the formation of small particles and to improve the film conformity. The great potential of the outlined reactions for micro- and nanofabrication is demonstrated by coating an ion-track etched polycarbonate membrane with a uniform Pd film of approximately 20 nm thickness. The as-prepared membrane is then employed as a highly miniaturized flow reactor, using the reduction of 4-nitrophenol with NaBH4 as a model reaction.

  18. On thermodynamic and microscopic reversibility

    Energy Technology Data Exchange (ETDEWEB)

    Crooks, Gavin E.

    2011-07-12

    The word 'reversible' has two (apparently) distinct applications in statistical thermodynamics. A thermodynamically reversible process indicates an experimental protocol for which the entropy change is zero, whereas the principle of microscopic reversibility asserts that the probability of any trajectory of a system through phase space equals that of the time reversed trajectory. However, these two terms are actually synonymous: a thermodynamically reversible process is microscopically reversible, and vice versa.

  19. Chemiluminescence analysis of amitriptyline hydrochloride with a nanometer microreactor%流动注射纳米微反应器化学发光法测定盐酸阿米替林

    Institute of Scientific and Technical Information of China (English)

    朱乾华

    2011-01-01

    In acidic condition, the nitrogen in amitriptyline hydrochloride was easily protonated and formed ion associated-complex with negative ion AuCl4-, the ion associated-complex was extracted and carried by dichloromethane, when the ion associated-complex entered a reversed micellar nanometer microreactor of cetyltrimethylammonium chlorine containing luminol, the dissociated AuCl4- reacted with luminol and produced an analytical chemiluminescence signal. Under the optimum conditions, the linear range is from 0.001 to 15 μg/mL and the limit of detection is 0.03 ng/mL. The relative standard deviation (RSD) is 2.4% for 1.0 μg/mL amitriptyline hydrochloride (n = 11 ). The method has been applied to the determination of the studied drug in tablets and biological fluids successfully.%在酸性条件下,盐酸阿米替林分子中氮原子被质子化后与阴离子AuCl4-形成离子缔合物,该缔合物被二氯甲烷带入鲁米诺的氯化十六烷基三甲基铵反胶束纳米微反应器中,离解出来的AuCl4-立即与鲁米诺产生化学发光.在一定浓度范围内,发光强度与盐酸阿米替林的含量成线性关系,从而间接测定盐酸阿米替林的含量.在优化的实验条件下,线性范围为0.001~15 μg/mL,检出限(38)为0.03 ng/mL,对浓度为1.0μg/mL的盐酸阿米替林进行11次平行测定,RSD为2.4%.该法已用于片荆和生物体液中盐酸阿米替林的测定.

  20. Logical Reversibility and Physical Reversibility in Quantum Measurement

    OpenAIRE

    Ueda, Masahito

    1997-01-01

    A quantum measurement is logically reversible if the premeasurement density operator of the measured system can be calculated from the postmeasurement density operator and from the outcome of the measurement. This paper analyzes why many quantum measurements are logically irreversible, shows how to make them logically reversible, and discusses reversing measurement that returns the postmeasurement state to the premeasurement state by another measurement (physical reversibility). Reversing mea...

  1. Economic impact of reversion

    International Nuclear Information System (INIS)

    Estimations of the Norwegian hydropower production and various reversion models' market value have been made. The value of the Norwegian hydropower production until 01.01.2007 is estimated to about Nok 289 billion after taxes, or about 2,42 Nok/kWh medium production, given an expected future electricity price of around 0,25 Nok/kWh and a discount rate at 6,5 percent in nominal terms after taxes. The estimate is slightly above the level of prices for Norwegian hydropower plants in the last 8-10 years. The value of reversion in private plants which today have a limited licence time is estimated to Nok 5,5 billion. The value of reversion in public-owned Norwegian hydropower plants are about Nok 21 billion with a 60 year licence period from 01.01.2007, and about 12 billion for 75 years (ml)

  2. Reversed extension flow

    DEFF Research Database (Denmark)

    Nielsen, Jens Kromann; Rasmussen, Henrik K.

    2008-01-01

    Afilament stretching rheometer (FSR) was used for measuring the start-up of uni-axial elongational flow followed by reversed bi-axial flow, both with a constant elongational rate. A narrow molecular mass distribution linear polystyrene with a molecular weight of 145 kg / mole wis subjected to the...... start-up of elongation for three Hencky strain units and subsequently the reversed flow. The integral molecular stress function formulation within the 'interchain pressure' concept agrees with the experiments. In the experiments the Hencky strain at which the str~ss becomes zero (the recovery strain) in...... the reversed flow has been identified. The recovery strain is found to increase with elongational rate, and has a maximum value of approximately 1.45. The Doi Edwards model using any stretch evolution equation is not able to predict the correct level of the recovery strain....

  3. Reversible deep disposal

    International Nuclear Information System (INIS)

    This presentation, given by the national agency of radioactive waste management (ANDRA) at the meeting of October 8, 2009 of the high committee for the nuclear safety transparency and information (HCTISN), describes the concept of deep reversible disposal for high level/long living radioactive wastes, as considered by the ANDRA in the framework of the program law of June 28, 2006 about the sustainable management of radioactive materials and wastes. The document presents the social and political reasons of reversibility, the technical means considered (containers, disposal cavities, monitoring system, test facilities and industrial prototypes), the decisional process (progressive development and blocked off of the facility, public information and debate). (J.S.)

  4. Characterization of hereditarily reversible posets

    OpenAIRE

    Kukieła, Michał

    2013-01-01

    A poset P is called reversible if every order preserving bijective self map of P is an order automorphism. P is called hereditarily reversible if every subposet of P is reversible. We give a complete characterization of hereditarily reversible posets in terms of forbidden subsets. A similar result is stated also for preordered sets. As a corollary we extend the list of known examples of hereditarily reversible topological spaces.

  5. Time reversal communication system

    Science.gov (United States)

    Candy, James V.; Meyer, Alan W.

    2008-12-02

    A system of transmitting a signal through a channel medium comprises digitizing the signal, time-reversing the digitized signal, and transmitting the signal through the channel medium. The channel medium may be air, earth, water, tissue, metal, and/or non-metal.

  6. Reversing insect pollinator decline

    OpenAIRE

    Potts, Simon; Wentworth, Jonathan

    2013-01-01

    Pollination by insects enables the reproduction of flowering plants and is critical to UK agriculture.1 Insect pollinators have declined globally, with implications for food security and wild habitats. This POSTnote summarises the causes for the recent trends, gaps in knowledge and possible strategies for reversing pollinator decline.

  7. Reversal Strategies for NOACs

    DEFF Research Database (Denmark)

    Husted, Steen; Verheugt, Freek; Comuth, Willemijn

    2015-01-01

    , coagulation factor concentrates or NOAC-specific antidotes could be used. Coagulation factor concentrates can be used in patients with haemophilia and to reverse the effect of VKAs but, in NOAC-treated patients, results are inconsistent and these agents could potentially have pro-thrombotic effects. Specific...

  8. Reversible focal splenial lesions

    Energy Technology Data Exchange (ETDEWEB)

    Gallucci, Massimo; Limbucci, Nicola [University of L' Aquila, Department of Radiology, S. Salvatore Hospital, L' Aquila (Italy); Paonessa, Amalia [Loreto Nuovo Hospital, Department of Neuroradiology, Napoli (Italy); Caranci, Ferdinando [Federico II University, Department of Neurological Sciences, Napoli (Italy)

    2007-07-15

    Reversible focal lesions in the splenium of the corpus callosum (SCC) have recently been reported.They are circumscribed and located in the median aspect of the SCC. On MRI, they are hyperintense on T2-W and iso-hypointense on T1-W sequences, with no contrast enhancement. On DWI, SCC lesions are hyperintense with low ADC values, reflecting restricted diffusion due to cytotoxic edema. The common element is the disappearance of imaging abnormalities with time, including normalization of DWI. Clinical improvement is often reported. The most established and frequent causes of reversible focal lesions of the SCC are viral encephalitis, antiepileptic drug toxicity/withdrawal and hypoglycemic encephalopathy. Many other causes have been reported, including traumatic axonal injury. The similar clinical and imaging features suggest a common mechanism induced by different pathological events leading to the same results. Edema and diffusion restriction in focal reversible lesions of the SCC have been attributed to excitotoxic mechanisms that can result from different mechanisms; no unifying relationship has been found to explain all the pathologies associated with SCC lesions. In our opinion, the similar imaging, clinical and prognostic aspects of these lesions depend on a high vulnerability of the SCC to excitotoxic edema and are less dependent on the underlying pathology. In this review, the relevant literature concerning reversible focal lesions in the SCC is analyzed and hypotheses about their pathogenesis are proposed. (orig.)

  9. Reverse Coherent Information

    Science.gov (United States)

    García-Patrón, Raúl; Pirandola, Stefano; Lloyd, Seth; Shapiro, Jeffrey H.

    2009-05-01

    In this Letter we define a family of entanglement distribution protocols assisted by feedback classical communication that gives an operational interpretation to reverse coherent information, i.e., the symmetric counterpart of the well-known coherent information. This leads to the definition of a new entanglement distribution capacity that exceeds the unassisted capacity for some interesting channels.

  10. Reverse Shoulder Arthroplasty

    Medline Plus

    Full Text Available Reverse Shoulder Arthroplasty Zimmer, Inc. New York City, New York March 17, 2010 Welcome to this OR Live presentation, brought to you by Zimmer. Hi. I'm ... my partner, Brad Parsons. We're here in New York to bring you a video of a ...

  11. Reverse Coherent Information

    OpenAIRE

    García-Patrón, Raúl; Pirandola, Stefano; Lloyd, Seth; Shapiro, Jeffrey H.

    2008-01-01

    In this letter we define a family of entanglement distribution protocols assisted by feedback classical communication that gives an operational interpretation to reverse coherent information, i.e., the symmetric counterpart of the well known coherent information. This lead to the definition of a new entanglement distribution capacity that exceeds the unassisted capacity for some interesting channels.

  12. 基于简化模型的T型微反应器设计%Optimal design of T-shaped microreactors by using a simplified model

    Institute of Scientific and Technical Information of China (English)

    王林

    2012-01-01

    Computational fluid dynamics models are effective in rigorously analyzing T-shaped microreactors. However, when they are applied to optimal design problems, it is necessary to reduce computational time. In this research, a simplified model is proposed to efficiently solve the optimal design problems of T-shaped microreactors. In the proposed model, the assuming boundary conditions and an artificial diffusivity are used to calculate the reaction yield distribution in the mixing channel. The assuming boundary conditions are used to describe the mixing effect on the inlet of the reactor, and the artificial diffusivity is used to express convective mixing caused by the flow through diffusive mixing. Meanwhile, based on the simplified model, an optimal design method is proposed to calculate the optimal size of T-shaped microreactors. The usefulness of the proposed model and the optimal design method is demonstrated through a fast consecutive-parallel reaction. The reaction yield is maximized by manipulating the width, height and length of mixing channel of an isothermal T-MR that meets the prescribed requirements for the pressure drop. The design result shows that the simplified model can accurately predict the yield distribution of the product along the mixing channel and that the simplified model based design method can reduce the design period of T shaped microreactors.%分析T型微反应器内流体混合程度和反应产物收率的常用方法是建立计算流体动态模型,也就是CFD模型,可是这种模型不适用于微反应器的优化设计,因为利用CFD模型进行优化计算需要的大量的计算时间.本研究开发了一个描述T型微反应器流体流动状态的简化模型,通过假设边界条件和假设扩散系数的设定来计算微反应器内反应产物收率.其中假设边界条件用来描述强混合效果在反应通道入口处的流动状态,假设扩散系数用来描述混合效果在流动路径上的变化.本研究

  13. Selection and application of catalyst supports in microreactors%微型反应器中催化剂载体的选择和应用

    Institute of Scientific and Technical Information of China (English)

    丁素萍; 刘娜; 费玥; 王奇; 庄明; 曾尚红

    2011-01-01

    形状规则的微通道是微型反应器最重要的组件,而陶瓷、不诱钢和FeCrAl是制造微通道常用的材料.评述了3种材料在微型反应器中的选择和应用,并指出优缺点,同时分析涂层和催化剂的形貌、特征及黏附性.%Microchannels made by ceramic, stainless steel and FeCrAl metallic supports are the most important components in microreactors. The selection and application of these materials were reviewed and their advantages and disadvantages were pointed out. The morphology, characteristic and adhesion of the coatings and the catalysts were analyzed.

  14. Ag/SiO2- and Ag/Co3O4-Based Monolithic Flow Microreactors for Hydrogenation of Dyes: Their Activity and Stability

    Directory of Open Access Journals (Sweden)

    Yasemin Hakat

    2015-02-01

    Full Text Available Silver nanoparticles supported on hierarchically porous silica and cobalt oxide monoliths have previously been shown to be catalytically active for the hydrogenation of common organic dyes in batch studies. This work presents a detailed investigation of the activity and stability of these monoliths during the hydrogenation of eosin-Y in a continuous flow microreactor. The silver-containing monoliths showed excellent catalytic activity that reached a plateau after a period of approximately 6 h. From SEM particle size distribution studies of the catalysts before and after water and hexane were flowed through them, it was determined that under reaction conditions, silver was removed both by washing off of particles and by dissolution of silver.

  15. Stereoselective Synthesis of 1,3-Diaminotruxillic Acid Derivatives: An Advantageous Combination of C-H-ortho-Palladation and On-Flow [2+2]-Photocycloaddition in Microreactors.

    Science.gov (United States)

    Serrano, Elena; Juan, Alberto; García-Montero, Angel; Soler, Tatiana; Jiménez-Márquez, Francisco; Cativiela, Carlos; Gomez, M Victoria; Urriolabeitia, Esteban P

    2016-01-01

    The stereoselective synthesis of ε-isomers of dimethyl esters of 1,3-diaminotruxillic acid in three steps is reported. The first step is the ortho-palladation of (Z)-2-aryl-4-aryliden-5(4H)-oxazolones 1 to give dinuclear complexes 2 with bridging carboxylates. The reaction occurs through regioselective activation of the ortho-CH bond of the 4-arylidene ring in carboxylic acids. The second step is the [2+2]-photocycloaddition of the CC exocyclic bonds of the oxazolone skeleton in 2 to afford the corresponding dinuclear ortho-palladated cyclobutanes 3. This key step was performed very efficiently by using LED light sources with different wavelengths (465, 525 or 625 nm) in flow microreactors. The final step involved the depalladation of 3 by hydrogenation in methanol to afford the ε-1,3-diaminotruxillic acid derivatives as single isomers. PMID:26597315

  16. Stabilization of Hydrogen Production via Methanol Steam Reforming in Microreactor by Al2O3 Nano-Film Enhanced Catalyst Adhesion.

    Science.gov (United States)

    Jeong, Heondo; Na, Jeong-Geol; Jang, Min Su; Ko, Chang Hyun

    2016-05-01

    In hydrogen production by methanol steam reforming reaction with microchannel reactor, Al2O3 thin film formed by atomic layer deposition (ALD) was introduced on the surface of microchannel reactor prior to the coating of catalyst particles. Methanol conversion rate and hydrogen production rate, increased in the presence of Al2O3 thin film. Over-view and cross-sectional scanning electron microscopy study showed that the adhesion between catalyst particles and the surface of microchannel reactor enhanced due to the presence of Al2O3 thin film. The improvement of hydrogen production rate inside the channels of microreactor mainly came from the stable fixation of catalyst particles on the surface of microchannels. PMID:27483762

  17. Structural basis of reverse nucleotide polymerization

    OpenAIRE

    Nakamura, Akiyoshi; Nemoto, Taiki; Heinemann, Ilka U.; Yamashita, Keitaro; Sonoda, Tomoyo; Komoda, Keisuke; Tanaka, Isao; Söll, Dieter; Yao, Min

    2013-01-01

    Template-dependent RNA and DNA polymerization is a vital reaction in the cell and is believed to occur exclusively in the forward direction (5′-3′), which poses significant challenges to the cell in, for example, lagging strand synthesis. Although cells are mostly limited to unidirectional polymerization, we find that reverse polymerization is structurally and chemically possible utilizing the same structural core, the conserved palm domain of canonical polymerases. The structure of a unique ...

  18. Liquid-liquid electro-organo-synthetic processes in a carbon nanofibre membrane microreactor: Triple phase boundary effects in the absence of intentionally added electrolyte

    Energy Technology Data Exchange (ETDEWEB)

    Watkins, John D.; Ahn, Sunyhik D.; Taylor, James E.; Bull, Steven D. [Department of Chemistry, University of Bath, Claverton Down, Bath BA2 7AY (United Kingdom); Bulman-Page, Philip C. [School of Chemistry, University of East Anglia, Norwich, Norfolk NR4 7TJ (United Kingdom); Marken, Frank, E-mail: F.Marken@bath.ac.uk [Department of Chemistry, University of Bath, Claverton Down, Bath BA2 7AY (United Kingdom)

    2011-07-30

    Graphical abstract: Display Omitted Highlights: > Amphiphilic carbon nanofiber membrane employed in electro-synthesis. > Triple phase boundary process within a carbon membrane. > Electrochemical deuteration in a liquid|liquid micro-reactor system. > Triple phase boundary reaction zone effects in electro-synthesis. - Abstract: An amphiphilic carbon nanofibre membrane electrode (ca. 50 nm fibre diameter, 50-100 {mu}m membrane thickness) is employed as an active working electrode and separator between an aqueous electrolyte phase (with reference and counter electrode) and an immiscible organic acetonitrile phase (containing only the redox active material). Potential control is achieved with a reference and counter electrode located in the aqueous electrolyte phase, but the electrolysis is conducted in the organic acetonitrile phase in the absence of intentionally added supporting electrolyte. For the one-electron oxidation of n-butylferrocene coupled to perchlorate anion transfer from aqueous to organic phase effective electrolysis is demonstrated with an apparent mass transfer coefficient of m = 4 x 10{sup -5} m s{sup -1} and electrolysis of typically 1 mg n-butylferrocene in a 100 {mu}L volume. For the two-electron reduction of tetraethyl-ethylenetetracarboxylate the apparent mass transfer coefficient m = 4 x 10{sup -6} m s{sup -1} is lower due to a less extended triple phase boundary reaction zone in the carbon nanofibre membrane. Nevertheless, effective electrolysis of up to 6 mg tetraethyl-ethylenetetracarboxylate in a 100 {mu}L volume is demonstrated. Deuterated products are formed in the presence of D{sub 2}O electrolyte media. The triple phase boundary dominated mechanism and future microreactor design improvements are discussed.

  19. Liquid-liquid electro-organo-synthetic processes in a carbon nanofibre membrane microreactor: Triple phase boundary effects in the absence of intentionally added electrolyte

    International Nuclear Information System (INIS)

    Graphical abstract: Display Omitted Highlights: → Amphiphilic carbon nanofiber membrane employed in electro-synthesis. → Triple phase boundary process within a carbon membrane. → Electrochemical deuteration in a liquid|liquid micro-reactor system. → Triple phase boundary reaction zone effects in electro-synthesis. - Abstract: An amphiphilic carbon nanofibre membrane electrode (ca. 50 nm fibre diameter, 50-100 μm membrane thickness) is employed as an active working electrode and separator between an aqueous electrolyte phase (with reference and counter electrode) and an immiscible organic acetonitrile phase (containing only the redox active material). Potential control is achieved with a reference and counter electrode located in the aqueous electrolyte phase, but the electrolysis is conducted in the organic acetonitrile phase in the absence of intentionally added supporting electrolyte. For the one-electron oxidation of n-butylferrocene coupled to perchlorate anion transfer from aqueous to organic phase effective electrolysis is demonstrated with an apparent mass transfer coefficient of m = 4 x 10-5 m s-1 and electrolysis of typically 1 mg n-butylferrocene in a 100 μL volume. For the two-electron reduction of tetraethyl-ethylenetetracarboxylate the apparent mass transfer coefficient m = 4 x 10-6 m s-1 is lower due to a less extended triple phase boundary reaction zone in the carbon nanofibre membrane. Nevertheless, effective electrolysis of up to 6 mg tetraethyl-ethylenetetracarboxylate in a 100 μL volume is demonstrated. Deuterated products are formed in the presence of D2O electrolyte media. The triple phase boundary dominated mechanism and future microreactor design improvements are discussed.

  20. Chemical recycling of carbon dioxide emissions from a cement plant into dimethyl ether, a case study of an integrated process in France using a Reverse Water Gas Shift (RWGS) step

    International Nuclear Information System (INIS)

    Recycling of carbon dioxide (CO2) and hydrogen (H2) into liquid fuel technology has recently gained wide public interest since it is a potential pathway to increase the liquid fuel supply and to mitigate CO2 emissions simultaneously. In France, the majority of the electricity production is derived from nuclear and renewable energy which have a low CO2 footprint. This electricity power enables a potential for massive hydrogen production with low carbon emissions. We studied the possibility to develop this technology at an industrial scale in the French context on a typical industrial example of a cement manufacture in the south of France. An integrated process is proposed, which enables the use of the heat released by the CO2 to fuel process to help to capture the CO2 released by the cement manufacture. Some technological issues are discussed, and a potential solution is proposed for the catalyst used in the critical step of the Reverse Water Gas-Shift reaction (RWGS) of the process. (authors)

  1. Gridded electron reversal ionizer

    Science.gov (United States)

    Chutjian, Ara (Inventor)

    1993-01-01

    A gridded electron reversal ionizer forms a three dimensional cloud of zero or near-zero energy electrons in a cavity within a filament structure surrounding a central electrode having holes through which the sample gas, at reduced pressure, enters an elongated reversal volume. The resultant negative ion stream is applied to a mass analyzer. The reduced electron and ion space-charge limitations of this configuration enhances detection sensitivity for material to be detected by electron attachment, such as narcotic and explosive vapors. Positive ions may be generated by generating electrons having a higher energy, sufficient to ionize the target gas and pulsing the grid negative to stop the electron flow and pulsing the extraction aperture positive to draw out the positive ions.

  2. Reverse engineering software ecosystems

    OpenAIRE

    Lungu, Mircea F.; Lanza, Michele

    2009-01-01

    Reverse engineering is an active area of research concerned with the development of techniques and tools that support the understanding of software systems. All the techniques that were pro- posed until now study individual systems in isolation. However, software systems are seldom developed in isolation; instead, they are developed together with other projects in the wider context of an organization. We call the collection of projects that are developed in such a con- text a software ...

  3. Time-reversal acoustics

    Energy Technology Data Exchange (ETDEWEB)

    Fink, Mathias [Laboratoire Ondes et Acoustique, Ecole Superieure de Physique et de Chimie Industrielle de la Ville de Paris, Universite Denis Diderot, UMR CNRS 7587, 10 Rue Vauquelin, 75005 Paris (France)], E-mail: mathias.fink@espci.fr

    2008-10-15

    Time-reversal mirrors (TRMs) refocus an incident acoustic field to the position of the original source regardless of the complexity of the propagation medium. TRM's have now been implemented in a variety of physical scenarios from MHz ultrasonics with order centimeter aperture size to hundreds/thousands of Hz in ocean acoustics with order hundred meter aperture size. Common to this broad range of scales is a remarkable robustness exemplified by observations at all scales that the more complex the medium between the probe source and the TRM, the sharper the focus. The relation between the medium complexity and the size of the focal spot is studied in this paper. It is certainly the most exciting property of TRM compared to standard focusing devices. A TRM acts as an antenna that uses complex environments to appears wider than it is, resulting for a broadband pulse in a refocusing quality that does not depend of the TRM aperture. In this paper, we investigate the time-reversal approach in various media of increasing complexity and we discuss the link existing between time-reversal approach and local helioseismology where Green's functions can be extracted from diffusive noise.

  4. 微通道反应器内异辛醇混硝化过程行为%Investigation of Nitration Processes of iso-Octanol with Mixed Acid in a Microreactor

    Institute of Scientific and Technical Information of China (English)

    沈佳妮; 赵玉潮; 陈光文; 袁权

    2009-01-01

    In this paper, the nitration characteristic of alcohols with mixed acid for the synthesis of energetic materials in a stainless steel microreactor was investigated experimentally. The nitration of /.vo-octanol with HNO3-H2SO4 mixed acid was chosen as a typical model reaction which involved fast and strong exothermic liquid-liquid heterogeneous reaction process. The influences of mixed acid composition, flow rate, organic/aqueous flow ratio and reaction temperature have been investigated. The results indicated that the reaction could be conducted safely and stably in the microreactor at 25 40 C, which are enhanced compared to 15 C or below for safe operating conditions in the conventional reactors. Moreover, the 98.2% conversion of (so-octanol could be obtained and no by-products were detected in all cases.

  5. Designing Parity Preserving Reversible Circuits

    OpenAIRE

    Paul, Goutam; Chattopadhyay, Anupam; Chandak, Chander

    2013-01-01

    Making a reversible circuit fault-tolerant is much more difficult than classical circuit and there have been only a few works in the area of parity-preserving reversible logic design. Moreover, all of these designs are ad hoc, based on some pre-defined parity preserving reversible gates as building blocks. In this paper, we for the first time propose a novel and systematic approach towards parity preserving reversible circuits design. We provide some related theoretical results and give two a...

  6. A Study on Reverse Logistics

    OpenAIRE

    Reddy, Dhananjaya

    2011-01-01

    In the competitive world of manufacturing, companies are often searching for new ways to improve their process, customer satisfaction and stay ahead in the game with their competitors. Reverse logistics has been considered a strategy to bring these things to life for the past decade or so. This thesis work tries to shed some light on the basics of reverse logistics and how reverse logistics can be used as a management strategy. This paper points out the fundamentals of reverse logistics and l...

  7. Surface molecular imprinting onto fluorescein-coated magnetic nanoparticlesvia reversible addition fragmentation chain transfer polymerization: A facile three-in-one system for recognition and separation of endocrine disrupting chemicals

    Science.gov (United States)

    Li, Ying; Dong, Cunku; Chu, Jia; Qi, Jingyao; Li, Xin

    2011-01-01

    In this study, we present a general protocol for the making of surface-imprinted magnetic fluorescence beads viareversible addition-fragmentation chain transfer polymerization. The resulting composites were characterized by X-ray diffraction analysis, transmission electron microscopy, scanning electron microscopy, fluorescence spectroscopy, Fourier transform infrared spectroscopy, and energy dispersive spectroscopy. The as-synthesized beads exhibited homogeneous polymer films (thickness of about 5.7 nm), spherical shape, high fluorescence intensity and magnetic property (Magnetization (Ms) = 3.67 emu g-1). The hybrids bind the original template 17β-estradiol with an appreciable selectivity over structurally related compounds. In addition, the resulting hybrids performed without obvious deterioration after five repeated cycles. This study therefore demonstrates the potential of molecularly imprinted polymers for the recognition and separation of endocrine disrupting chemicals.In this study, we present a general protocol for the making of surface-imprinted magnetic fluorescence beads viareversible addition-fragmentation chain transfer polymerization. The resulting composites were characterized by X-ray diffraction analysis, transmission electron microscopy, scanning electron microscopy, fluorescence spectroscopy, Fourier transform infrared spectroscopy, and energy dispersive spectroscopy. The as-synthesized beads exhibited homogeneous polymer films (thickness of about 5.7 nm), spherical shape, high fluorescence intensity and magnetic property (Magnetization (Ms) = 3.67 emu g-1). The hybrids bind the original template 17β-estradiol with an appreciable selectivity over structurally related compounds. In addition, the resulting hybrids performed without obvious deterioration after five repeated cycles. This study therefore demonstrates the potential of molecularly imprinted polymers for the recognition and separation of endocrine disrupting chemicals. Electronic

  8. Reverse Engineering of RFID devices

    OpenAIRE

    Bokslag, Wouter

    2015-01-01

    This paper discusses the relevance and potential impact of both RFID and reverse engineering of RFID technology, followed by a discussion of common protocols and internals of RFID technology. The focus of the paper is on providing an overview of the different approaches to reverse engineering RFID technology and possible countermeasures that could limit the potential of such reverse engineering attempts.

  9. Reversible brazing process

    Science.gov (United States)

    Pierce, Jim D.; Stephens, John J.; Walker, Charles A.

    1999-01-01

    A method of reversibly brazing surfaces together. An interface is affixed to each surface. The interfaces can be affixed by processes such as mechanical joining, welding, or brazing. The two interfaces are then brazed together using a brazing process that does not defeat the surface to interface joint. Interfaces of materials such as Ni-200 can be affixed to metallic surfaces by welding or by brazing with a first braze alloy. The Ni-200 interfaces can then be brazed together using a second braze alloy. The second braze alloy can be chosen so that it minimally alters the properties of the interfaces to allow multiple braze, heat and disassemble, rebraze cycles.

  10. Reverse engineering SPARQL queries

    OpenAIRE

    Arenas, M; Diaz, GI; Kostylev, E

    2016-01-01

    Semantic Web systems provide open interfaces for end-users to access data via a powerful high-level query language, SPARQL. But users unfamiliar with either the details of SPARQL or properties of the target dataset may find it easier to query by example — give examples of the information they want (or examples of both what they want and what they do not want) and let the system reverse engineer the desired query from the examples. This approach has been heavily used in th...

  11. Reverse Engineering Malicious Applications

    Directory of Open Access Journals (Sweden)

    Ioan Cristian Iacob

    2015-06-01

    Full Text Available Detecting new and unknown malware is a major challenge in today’s software. Security profession. A lot of approaches for the detection of malware using data mining techniques have already been proposed. Majority of the works used static features of malware. However, static detection methods fall short of detecting present day complex malware. Although some researchers proposed dynamic detection methods, the methods did not use all the malware features. In this work, an approach for the detection of new and unknown malware was proposed and implemented. Each sample was reverse engineered for analyzing its effect on the operating environment and to extract the static and behavioral features. 

  12. Aproveitamento sustentável de biomassa e de recursos naturais na inovação química Sustainable use fo biomass and natural resources for chemical innovation

    Directory of Open Access Journals (Sweden)

    Fernando Galembeck

    2009-01-01

    Full Text Available Increased production of biomass is currently the only immediately accessible alternative for large-scale carbon sequestration and it can produce large amounts of food, fuel and raw materials for the chemical industry that can in turn growingly replace oil as a source of organic building blocks and also of hydrogen and sulfur. Development of processes for biomass and abundant minerals transformation into chemical raw materials should now benefit from large inputs from nanotechnologies, biotechnologies, information and micro-reactor technologies. Success in R&D&Innovation along this line can yield new products and processes needed to perform desirable functions within a sustainable development paradigm.

  13. What Do Reversible Programs Compute?

    DEFF Research Database (Denmark)

    Axelsen, Holger Bock; Glück, Robert

    2011-01-01

    Reversible computing is the study of computation models that exhibit both forward and backward determinism. Understanding the fundamental properties of such models is not only relevant for reversible programming, but has also been found important in other fields, e.g., bidirectional model...... transformation, program transformations such as inversion, and general static prediction of program properties. Historically, work on reversible computing has focussed on reversible simulations of irreversible computations. Here, we take the viewpoint that the property of reversibility itself should be the...... starting point of a computational theory of reversible computing. We provide a novel semantics-based approach to such a theory, using reversible Turing machines (RTMs) as the underlying computation model. We show that the RTMs can compute exactly all injective, computable functions. We find that the RTMs...

  14. Reverse Quantum Waves

    Science.gov (United States)

    Boyd, Jeffrey

    2010-02-01

    As preposterous as it might sound, if quantum waves travel in the reverse direction from subatomic particles, then most of quantum physics can be explained without quantum weirdness or Schr"odinger's cat. Quantum mathematics is unchanged. The diffraction pattern on the screen of the double slit experiment is the same. This proposal is not refuted by the Innsbruck experiments; this is NOT a hidden local variable theory. Research evidence will be presented that is consistent with the idea waves travel in the opposite direction as neutrons. If one's thinking shifts from forwards to backwards quantum waves, the world changes so drastically it is almost unimaginable. Quantum waves move from the mathematical to the real world, multiply in number, and reverse in direction. Wave-particle duality is undone. In the double slit experiment every part of the target screen is emitting such quantum waves in all directions. Some pass through the two slits. Interference occurs on the opposite side of the barrier than is usually imagined. They impinge on ``S'' and an electron is released at random. Because of the interference it is more likely to follow some waves than others. It follows one and only one wave backward; hitting the screen where it's wave originated. )

  15. Reversibly Bistable Flexible Electronics

    KAUST Repository

    Alfaraj, Nasir

    2015-05-01

    Introducing the notion of transformational silicon electronics has paved the way for integrating various applications with silicon-based, modern, high-performance electronic circuits that are mechanically flexible and optically semitransparent. While maintaining large-scale production and prototyping rapidity, this flexible and translucent scheme demonstrates the potential to transform conventionally stiff electronic devices into thin and foldable ones without compromising long-term performance and reliability. In this work, we report on the fabrication and characterization of reversibly bistable flexible electronic switches that utilize flexible n-channel metal-oxide-semiconductor field-effect transistors. The transistors are fabricated initially on rigid (100) silicon substrates before they are peeled off. They can be used to control flexible batches of light-emitting diodes, demonstrating both the relative ease of scaling at minimum cost and maximum reliability and the feasibility of integration. The peeled-off silicon fabric is about 25 µm thick. The fabricated devices are transferred to a reversibly bistable flexible platform through which, for example, a flexible smartphone can be wrapped around a user’s wrist and can also be set back to its original mechanical position. Buckling and cyclic bending of such host platforms brings a completely new dimension to the development of flexible electronics, especially rollable displays.

  16. Reversible posterior leukoencephalopathy syndrome

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Eun Ja; Yu, Won Jong; Ahn, Kook Jin; Jung, So Lyung; Lee, Yeon Soo; Kim, Ji Chang; Kang, Si Won [The Catholic Univ. of Korea, Taejon (Korea, Republic of); Song, Chang Joon [Chungnam National Univ. School of Medicine, Cheonju (Korea, Republic of); Song, Soon-Young; Koo, Ja Hong [Kwandong Univ. College of Medicine, Myungji Hospital, Seoul (Korea, Republic of); Kim, Man Deuk [College of Medicine Pochon CHA Univ., Seoul (Korea, Republic of)

    2001-10-01

    To review reversible posterior leukoencephalopathy syndrome. We reviewed 22 patients (M:F=3:19; age, 17-46 years) with the characteristic clinical and imaging features of reversible posterior leukoencephalopathy syndrome. All underwent brain MRI, and in three cases both CT and MRI were performed. In one, MRA was obtained, and in eleven, follow-up MR images were obtained. We evaluated the causes of this syndrome, its clinical manifestations, and MR findings including the locations of lesions, the presence or absence of contrast enhancement, and the changes seen at follow-up MRI. Of the 22 patients, 13 had eclampsia (six during pregnancy and seven during puerperium). Four were receiving immunosuppressive therapy (three, cyclosporine ; one, FK 506). Four suffered renal failure and one had complicated migraine. The clinical manifestations included headache (n=12), visual disturbance (n=13), seizure (n=15), focal neurologic sign (n=3), and altered mental status (n=2). Fifteen patients had hypertension and the others normotension. MRI revealed that lesions were bilateral (n=20) or unilateral (n=2). In all patients the lesion was found in the cortical and subcortical areas of the parieto-occipital lobes ; other locations were the basal ganglia (n=9), posterior temporal lobe (n=8), frontal lobe (n=5), cerebellum (n=5), pons (n=2), and thalamus (n=1). All lesions were of high signal intensity on T2-weighted images, and of iso to low intensity on T1-weighted images. One was combined with acute hematoma in the left basal ganglia. In eight of 11 patients who underwent postcontrast T1-weighted MRI, there was no definite enhancement ; in one, enhancement was mild, and in tow, patchy. CT studies showed low attenuation, and MRA revealed mild vasospasm. The symptoms of all patients improved. Follow-up MRI in nine of 11 patients depicted complete resolution of the lesions ; in two, small infarctions remained but the extent of the lesions had decreased. Reversible posterior

  17. Reversible posterior leukoencephalopathy syndrome

    International Nuclear Information System (INIS)

    To review reversible posterior leukoencephalopathy syndrome. We reviewed 22 patients (M:F=3:19; age, 17-46 years) with the characteristic clinical and imaging features of reversible posterior leukoencephalopathy syndrome. All underwent brain MRI, and in three cases both CT and MRI were performed. In one, MRA was obtained, and in eleven, follow-up MR images were obtained. We evaluated the causes of this syndrome, its clinical manifestations, and MR findings including the locations of lesions, the presence or absence of contrast enhancement, and the changes seen at follow-up MRI. Of the 22 patients, 13 had eclampsia (six during pregnancy and seven during puerperium). Four were receiving immunosuppressive therapy (three, cyclosporine ; one, FK 506). Four suffered renal failure and one had complicated migraine. The clinical manifestations included headache (n=12), visual disturbance (n=13), seizure (n=15), focal neurologic sign (n=3), and altered mental status (n=2). Fifteen patients had hypertension and the others normotension. MRI revealed that lesions were bilateral (n=20) or unilateral (n=2). In all patients the lesion was found in the cortical and subcortical areas of the parieto-occipital lobes ; other locations were the basal ganglia (n=9), posterior temporal lobe (n=8), frontal lobe (n=5), cerebellum (n=5), pons (n=2), and thalamus (n=1). All lesions were of high signal intensity on T2-weighted images, and of iso to low intensity on T1-weighted images. One was combined with acute hematoma in the left basal ganglia. In eight of 11 patients who underwent postcontrast T1-weighted MRI, there was no definite enhancement ; in one, enhancement was mild, and in tow, patchy. CT studies showed low attenuation, and MRA revealed mild vasospasm. The symptoms of all patients improved. Follow-up MRI in nine of 11 patients depicted complete resolution of the lesions ; in two, small infarctions remained but the extent of the lesions had decreased. Reversible posterior

  18. Partial Reversible Gates(PRG) for Reversible BCD Arithmetic

    OpenAIRE

    Thapliyal, Himanshu; Arabnia, Hamid R; Bajpai, Rajnish; Sharma, Kamal K

    2007-01-01

    IEEE 754r is the ongoing revision to the IEEE 754 floating point standard and a major enhancement to the standard is the addition of decimal format. Furthermore, in the recent years reversible logic has emerged as a promising computing paradigm having its applications in low power CMOS, quantum computing, nanotechnology, and optical computing. The major goal in reversible logic is to minimize the number of reversible gates and garbage outputs. Thus, this paper proposes the novel concept of pa...

  19. Reverse Osmosis Optimization

    Energy Technology Data Exchange (ETDEWEB)

    None

    2013-08-01

    This technology evaluation was prepared by Pacific Northwest National Laboratory on behalf of the U.S. Department of Energy’s Federal Energy Management Program (FEMP). The technology evaluation assesses techniques for optimizing reverse osmosis (RO) systems to increase RO system performance and water efficiency. This evaluation provides a general description of RO systems, the influence of RO systems on water use, and key areas where RO systems can be optimized to reduce water and energy consumption. The evaluation is intended to help facility managers at Federal sites understand the basic concepts of the RO process and system optimization options, enabling them to make informed decisions during the system design process for either new projects or recommissioning of existing equipment. This evaluation is focused on commercial-sized RO systems generally treating more than 80 gallons per hour.

  20. Reverse Osmosis Optimization

    Energy Technology Data Exchange (ETDEWEB)

    McMordie Stoughton, Kate; Duan, Xiaoli; Wendel, Emily M.

    2013-08-26

    This technology evaluation was prepared by Pacific Northwest National Laboratory on behalf of the U.S. Department of Energy’s Federal Energy Management Program (FEMP). ¬The technology evaluation assesses techniques for optimizing reverse osmosis (RO) systems to increase RO system performance and water efficiency. This evaluation provides a general description of RO systems, the influence of RO systems on water use, and key areas where RO systems can be optimized to reduce water and energy consumption. The evaluation is intended to help facility managers at Federal sites understand the basic concepts of the RO process and system optimization options, enabling them to make informed decisions during the system design process for either new projects or recommissioning of existing equipment. This evaluation is focused on commercial-sized RO systems generally treating more than 80 gallons per hour.¬

  1. Reverse photoacoustic standoff spectroscopy

    Science.gov (United States)

    Van Neste, Charles W.; Senesac, Lawrence R.; Thundat, Thomas G.

    2011-04-12

    A system and method are disclosed for generating a reversed photoacoustic spectrum at a greater distance. A source may emit a beam to a target and a detector measures signals generated as a result of the beam being emitted on the target. By emitting a chopped/pulsed light beam to the target, it may be possible to determine the target's optical absorbance by monitoring the intensity of light collected at the detector at different wavelengths. As the wavelength of light is changed, the target may absorb or reject each optical frequency. Rejection may increase the intensity at the sensing element and absorption may decrease the intensity. Accordingly, an identifying spectrum of the target may be made with the intensity variation of the detector as a function of illuminating wavelength.

  2. Reverse osmosis application studies

    International Nuclear Information System (INIS)

    To assess the feasibility of applying reverse osmosis (RO) and ultrafiltration (UF) for effective treatment of process and waste streams from operations at Ontario Hydro's thermal and nuclear stations, an extensive literature survey has been carried out. It is concluded that RO is not at present economic for pretreatment of Great Lakes water prior to ion exchange demineralization for boiler makeup. Using both conventional and novel commercial membrane modules, RO pilot studies are recommended for treatment of boiler cleaning wastes, fly ash leachates, and flue gas desulphurization scrubber discharges for removal of heavy metals. Volume reduction and decontamination of nuclear station low-level active liquid waste streams by RO/UF also appear promising. Research programmes are proposed

  3. Fabrication of microcapsule arrays on chemically patterned surfaces via covalent linking

    Institute of Scientific and Technical Information of China (English)

    Jie YANG; Chang-you GAO

    2009-01-01

    A method for fabricating arrays ofmicrocapsules covalently immobilized onto chemically patterned substrates was developed. The core-shell microparticles with poly(allylamine hydrochloride) (PAH) as the outermost layer were obtained by layer-by-layer (LbL) assembly, which were further treated with glutaraldehyde to endow the particles with abundant aldehyde groups on their surfaces. The particles were then covalently coupled to the chemically patterned regions with amino groups created by microcontact printing (μCP). After dissolution of the core particles, arrays of the hollow microcapsules with unchanged structures were obtained. These arrays could stand rigorous environmental conditions of higher ionic strength, and lower and higher pH values. Thus, the technique could be possibly applied to exploiting chips of microcontainers or microreactors in sensing technology.

  4. An Algebra of Reversible Quantum Computing

    OpenAIRE

    Wang, Yong

    2015-01-01

    Based on the axiomatization of reversible computing RACP, we generalize it to quantum reversible computing which is called qRACP. By use of the framework of quantum configuration, we show that structural reversibility and quantum state reversibility must be satisfied simultaneously in quantum reversible computation. RACP and qRACP has the same axiomatization modulo the so-called quantum forward-reverse bisimularity, that is, classical reversible computing and quantum reversible computing are ...

  5. Towards a Reversible Functional Language

    DEFF Research Database (Denmark)

    Yokoyama, Tetsuo; Axelsen, Holger Bock; Glück, Robert

    2011-01-01

    /equality operator also simplifies inverse computation and program inversion. We discuss the advantages of a reversible functional language using example programs, including run-length encoding. Program inversion is seen to be as lightweight as for imperative reversible languages and realized by recursive descent......We identify concepts of reversibility for a functional language by means of a set of semantic rules with specific properties. These properties include injectivity along with local backward determinism, an important operational property for an efficient reversible language. We define a concise...... reversible first-order functional language in which access to the backward semantics is provided to the programmer by inverse function calls. Reversibility guarantees that in this language a backward run (inverse interpretation) is as fast as the corresponding forward run itself. By adopting a symmetric...

  6. Company policy toward reverse logistics

    OpenAIRE

    Klapalová Alena; Králová Maria

    2012-01-01

    The paper deals with the results of questionnaire survey examining the character of companies’ policies towards management of reverse flows logistics, namely innovativeness of policy related to the reasons of involvement to manage reverse flows and to the planning system of reverse logistics. Answers from the informants and respondents from 150 Czech companies were analysed with the employment of statistical methods (frequencies, contingency tables and Man – Whitney test) to explore the poten...

  7. Geomagnetic Reversals during the Phanerozoic.

    Science.gov (United States)

    McElhinny, M W

    1971-04-01

    An antalysis of worldwide paleomagnetic measurements suggests a periodicity of 350 x 10(6) years in the polarity of the geomagnetic field. During the Mesozoic it is predominantly normal, whereas during the Upper Paleozoic it is predominantly reversed. Although geomagnetic reversals occur at different rates throughout the Phanerozoic, there appeaars to be no clear correlation between biological evolutionary rates and reversal frequency. PMID:17735224

  8. Magnetic reversals and mass extinctions

    Science.gov (United States)

    Raup, D. M.

    1985-01-01

    The results of a study of reversals of the earth's magnetic field over the past 165 Myr are presented. A stationary periodicity of 30 Myr emerges which predicts pulses of increased reversal activity centered at 10, 40, 70, . . . Myr before the present. The correlation between the reversal intensity and biological extinctions is examined, and a nontrivial discrepancy is found between the magnetic and extinction periodicity.

  9. Magnetic Reversal on Vicinal Surfaces

    OpenAIRE

    Hyman, R. A.; Zangwill, A.; Stiles, M. D.

    1998-01-01

    We present a theoretical study of in-plane magnetization reversal for vicinal ultrathin films using a one-dimensional micromagnetic model with nearest-neighbor exchange, four-fold anisotropy at all sites, and two-fold anisotropy at step edges. A detailed "phase diagram" is presented that catalogs the possible shapes of hysteresis loops and reversal mechanisms as a function of step anisotropy strength and vicinal terrace length. The steps generically nucleate magnetization reversal and pin the...

  10. 49 CFR 230.89 - Reverse gear.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Reverse gear. 230.89 Section 230.89 Transportation... Reversing Gear § 230.89 Reverse gear. (a) General provisions. Reverse gear, reverse levers, and quadrants... quadrant. Proper counterbalance shall be provided for the valve gear. (b) Air-operated power reverse...

  11. An origin of the reversed remanent magnetization of rocks

    International Nuclear Information System (INIS)

    Complete text of publication follows. More like one century the field-reversal hypothesis has been accepted to explain an origin of the reversed remanent magnetization (RM) of rocks. The experimental evidences and the theoretical principles do support the self-reversal origin of the RM of several rocks. The recent rhyodacites of the intermediate hematite-ilmenite (Hem-Ilm) composition posses the self-reversed origin of the thermoremanent magnetization (TRM) from localities: Mt. Haruna - Japan, Mt. Shasta - USA, Mt. St. Helen - USA (the self-reversal tendency of the TRM was proven by my results), the 1991 Pinatubo eruption and from three other localities from Philippines. From my study follows that also the titanomagnetite (Ti-Mt) is a source of the self-reversed PTRM in Haruna rhyodacite. I revealed an increase of the reversed intensity of the TRM of Haruna and Olongapo (Philippines) rhyodacite rocks down to -196 deg C. I can deduce, that an ordering of the magnetic ions in the crystalline lattice of the Hem-Ilm is the dominant phenomenon of this type of the self-reversal. The second type: The self-reversal of the chemical remanent magnetization (CRM) of rocks due to the reordering of the magnetic ions and so the reversal of spontaneous magnetization in the crystalline A and B sub-lattices of the ferrimagnetic Ti-Mt - Ti-Mgh solid solutions. My results of basalts from Slovak volcanic fields, Bohemian Massif, Syria and Nigeria have proven that the rocks containing the low-temperature oxidized phase carry the reversed CRM. The self-reversed PTRM was induced also in the artificially prepared basaltic samples and in the andesite and rhyolite samples from about 177 outcrops. The self-reversed CRM of oxidized continental and sub-marine basalts was revealed also by foreign authors. The third type: The self-reversal RM was revealed in highly-temperature oxidized basalts containing dominantly the Hem-Ilm -es of low Ilm content. No self-reversal RM (TRM or CRM) is present in

  12. ASYMMETRIC SOLAR POLAR FIELD REVERSALS

    International Nuclear Information System (INIS)

    The solar polar fields reverse because magnetic flux from decaying sunspots moves toward the poles, with a preponderance of flux from the trailing spots. If there is a strong asymmetry, in the sense that most activity is in the northern hemisphere, then that excess flux will move toward the north pole and reverse that pole first. If there is more activity in the south later on, then that flux will help to reverse the south pole. In this way, two humps in the solar activity and a corresponding difference in the time of reversals develop (in the ideal case). Such a difference was originally noted in the very first observation of polar field reversal just after the maximum of the strongly asymmetric solar cycle 19, when the southern hemisphere was most active before sunspot maximum and the south pole duly reversed first, followed by the northern hemisphere more than a year later, when that hemisphere became most active. Solar cycles since then have had the opposite asymmetry, with the northern hemisphere being most active before solar maximum. We show that polar field reversals for these cycles have all happened in the north first, as expected. This is especially noteworthy for the present solar cycle 24. We suggest that the association of two or more peaks of solar activity when separated by hemispheres with correspondingly different times of polar field reversals is a general feature of the cycle, and that asymmetric polar field reversals are simply a consequence of the asymmetry of solar activity.

  13. Initiation of HIV Reverse Transcription

    Directory of Open Access Journals (Sweden)

    Roland Marquet

    2010-01-01

    Full Text Available Reverse transcription of retroviral genomes into double stranded DNA is a key event for viral replication. The very first stage of HIV reverse transcription, the initiation step, involves viral and cellular partners that are selectively packaged into the viral particle, leading to an RNA/protein complex with very specific structural and functional features, some of which being, in the case of HIV-1, linked to particular isolates. Recent understanding of the tight spatio-temporal regulation of reverse transcription and its importance for viral infectivity further points toward reverse transcription and potentially its initiation step as an important drug target.

  14. Screening HIV-1 fusion inhibitors based on capillary electrophoresis head-end microreactor targeting to the core structure of gp41.

    Science.gov (United States)

    Liu, Lihong; Xu, Xiaoying; Liu, Yanhui; Zhang, Xuanxuan; Li, Lin; Jia, Zhimin

    2016-02-20

    In this paper, we design a microreactor based on electrophoretically mediated microanalysis (EMMA) with capillary electrophoresis (CE) for screening HIV-1 inhibitors that bind to the N-terminal heptad repeat (NHR, N36) region. Initially, a test sample plug is loaded into a capillary filled with buffer solution followed by N36 peptide solution, and the two solutions simultaneously mix by diffusion. Then, voltage is applied, and the sample molecules pass through the N36 peptide zone. The active compounds combine with N36, leading to a loss in the peak height of the active compound. More than 100 traditional Chinese medicine extracts (TCME) were screened, and an extract of Pheretima aspergillum (E. Perrier) (L5) was identified as having potent inhibitory activity. The results showed that L5 could significantly inhibit the HIV-1JR-FL pseudotyped virus infection; the 50% effective concentration (EC50) of L5 was approximately 32.1±1.2μg/mL, and the 50% cytotoxicity concentration (CC50) value of L5 was 146.9±4.4μg/mL, suggesting that L5 had low in vitro cytotoxicity on U87-CD4-CCR5 cells. The new method is simple and rapid, is free of antibodies, and does not require tedious processes. PMID:26730512

  15. Auto-Thermal Reforming of Jet-A Fuel over Commercial Monolith Catalysts: MicroReactor Evaluation and Screening Test Results

    Science.gov (United States)

    Yen, Judy C. H.; Tomsik, Thomas M.

    2004-01-01

    This paper describes the results of a series of catalyst screening tests conducted with Jet-A fuel under auto-thermal reforming (ATR) process conditions at the research laboratories of SOFCo-EFS Holdings LLC under Glenn Research Center Contract. The primary objective is to identify best available catalysts for future testing at the NASA GRC 10-kW(sub e) reformer test facility. The new GRC reformer-injector test rig construction is due to complete by March 2004. Six commercially available monolithic catalyst materials were initially selected by the NASA/SOFCo team for evaluation and bench scale screening in an existing 0.05 kW(sub e) microreactor test apparatus. The catalyst screening tests performed lasted 70 to 100 hours in duration in order to allow comparison between the different samples over a defined range of ATR process conditions. Aging tests were subsequently performed with the top two ranked catalysts as a more representative evaluation of performance in a commercial aerospace application. The two catalyst aging tests conducted lasting for approximately 600 hours and 1000 hours, respectively.

  16. A Reversible Processor Architecture and its Reversible Logic Design

    DEFF Research Database (Denmark)

    Thomsen, Michael Kirkedal; Axelsen, Holger Bock; Glück, Robert

    2012-01-01

    We describe the design of a purely reversible computing architecture, Bob, and its instruction set, BobISA. The special features of the design include a simple, yet expressive, locally-invertible instruction set, and fully reversible control logic and address calculation. We have designed an arch...

  17. Chemical Emergencies

    Science.gov (United States)

    When a hazardous chemical has been released, it may harm people's health. Chemical releases can be unintentional, as in the case of an ... the case of a terrorist attack with a chemical weapon. Some hazardous chemicals have been developed by ...

  18. Design of Reversible Sequential Circuit Using Reversible Logic Synthesis

    Directory of Open Access Journals (Sweden)

    Md. Mosharof Hossin

    2012-01-01

    Full Text Available Reversible logic is one of the most vital issue at present time and it has different areas for its application, those are low power CMOS, quantum computing, nanotechnology, cryptography, optical computing, DNA computing, digital signal processing (DSP, quantum dot cellular automata, communication, computer graphics. It is not possible to realize quantum computing without implementation of reversible logic. The main purposes of designing reversible logic are to decrease quantum cost, depth of the circuits and the number of garbage outputs. In this paper, we have proposed a new reversible gate. And we have designedRS flip flop and D flip flop by using our proposed gate and Peres gate. The proposed designs are better than the existing proposed ones in terms of number of reversible gates and garbage outputs. So, this realization is more efficient and less costly than other realizations.

  19. Design of Reversible Sequential Circuit Using Reversible Logic Synthesis

    Directory of Open Access Journals (Sweden)

    Md. Belayet Ali

    2011-12-01

    Full Text Available Reversible logic is one of the most vital issue at present time and it has different areas for its application,those are low power CMOS, quantum computing, nanotechnology, cryptography, optical computing, DNA computing, digital signal processing (DSP, quantum dot cellular auto meta, communication, computer graphics. It is not possible to realize quantum computing without implementation of reversible logic. The main purposes of designing reversible logic are to decrease quantum cost, depth of the circuits and the number of garbage outputs. In this paper, we have proposed a new reversible gate. And we have designed RS flip flop and D flip flop by using our proposed gate and Peres gate. The proposed designs are better than the existing proposed ones in terms of number of reversible gates and garbage outputs. So, this realization is more efficient and less costly than other realizations.

  20. X-ray Microspectroscopy and Chemical Reactions in Soil Microsites

    Energy Technology Data Exchange (ETDEWEB)

    D Hesterberg; M Duff; J Dixon; M Vepraskas

    2011-12-31

    Soils provide long-term storage of environmental contaminants, which helps to protect water and air quality and diminishes negative impacts of contaminants on human and ecosystem health. Characterizing solid-phase chemical species in highly complex matrices is essential for developing principles that can be broadly applied to the wide range of notoriously heterogeneous soils occurring at the earth's surface. In the context of historical developments in soil analytical techniques, we describe applications of bulk-sample and spatially resolved synchrotron X-ray absorption spectroscopy (XAS) for characterizing chemical species of contaminants in soils, and for determining the uniqueness of trace-element reactivity in different soil microsites. Spatially resolved X-ray techniques provide opportunities for following chemical changes within soil microsites that serve as highly localized chemical micro- (or nano-)reactors of unique composition. An example of this microreactor concept is shown for micro-X-ray absorption near edge structure analysis of metal sulfide oxidation in a contaminated soil. One research challenge is to use information and principles developed from microscale soil chemistry for predicting macroscale and field-scale behavior of soil contaminants.

  1. An interlacing theorem for reversible Markov chains

    International Nuclear Information System (INIS)

    Reversible Markov chains are an indispensable tool in the modeling of a vast class of physical, chemical, biological and statistical problems. Examples include the master equation descriptions of relaxing physical systems, stochastic optimization algorithms such as simulated annealing, chemical dynamics of protein folding and Markov chain Monte Carlo statistical estimation. Very often the large size of the state spaces requires the coarse graining or lumping of microstates into fewer mesoscopic states, and a question of utmost importance for the validity of the physical model is how the eigenvalues of the corresponding stochastic matrix change under this operation. In this paper we prove an interlacing theorem which gives explicit bounds on the eigenvalues of the lumped stochastic matrix. (fast track communication)

  2. Field reversal experiments (FRX)

    International Nuclear Information System (INIS)

    The equilibrium, confinement, and stability properties of the reversed-field configuration (RFC) are being studied in two theta-pinch facilities. The RFC is an elongated toroidal plasma confined in a purely poloidal field geometry. The open field lines of the linear theta pinch support the closed-field RFC much like the vertical field centers the toroidal plasma in a tokamak. Depending on stability and confinement properties, the RFC might be used to greatly reduce the axial losses in linear fusion devices such as mirrors, theta pinches, and liners. The FRX systems produce RFC's with a major radius R = 2-6 cm, minor radius a approximately 2 cm, and a total length l approximately 35 cm. The observed temperatures are T/sub e/ approximately 100 eV and T/sub i/ = 150-350 eV with a peak density n approximately 2 x 1015 cm-3. After the plasma reaches equilibrium, the RFC remains stable for up to 30 μs followed by the rapid growth of the rotational m = 2 instability, which terminates the confinement. During the stable equilibrium, the particle and energy confinement times are more than 10 times longer than in an open-field system. The behavior of the m = 2 mode qualitatively agrees with the theoretically predicted instability for rotational velocities exceeding some critical value

  3. Driving forward in reverse

    International Nuclear Information System (INIS)

    We describe the use of TILLING in Lotus japonicus and the development of deletion (De)-TILLING in Medicago truncatula. The evolution of RevGenUK has been driven by the development of reverse genetics technologies in these two model legumes and Brassica rapa, which functions as a translational species for brassica crops. TILLING and De-TILLING, are underpinned by populations of plants mutagenised with either EMS (that causes point mutations) or fast neutrons (that cause deletions) respectively. They permit the isolation of either allelic series of mutants or knockouts. Mutation detection will be developed from a number of independent gel-based systems to be carried out on a single platform - capillary electrophoresis. We are currently TILLING in both model legumes, but these developments will be applied to all three species. The resource will develop an open source database-driven system to support laboratory information management, analysis and the cataloguing of mutants in a genome context across all the species. (author)

  4. Field reversal experiments (FRX)

    International Nuclear Information System (INIS)

    The equilibrium, confinement, and stability properties of the reversed-field configuration (RFC) are being studied in two theta-pinch facilities. The RFC is an elongated toroidal plasma confined in a purely poloidal field geometry. The open field lines of the linear theta pinch support the closed-field RFC much like the vertical field centres the toroidal plasma in a tokamak. Depending on stability and confinement properties, the RFC might be used to greatly reduce the axial losses in linear fusion devices such as mirrors, theta pinches, and liners. The FRX systems produce RFCs with a major radius R=2-6cm, a minor radius a approximately 2cm, and a total length l approximately 35cm. The observed temperatures are Tsub(e) approximately 100eV and Tsub(i)=150-350eV with a peak density n approximately 2x1015cm-3. After the plasma has reached equilibrium, the RFC remains stable for up to 30μs, followed by the rapid growth of the rotational m=2 instability, which terminates the confinement. During the stable equilibrium, the particle and energy confinement times are more than 10 times longer than in an open-field system. The behaviour of the m=2 mode agrees qualitatively with the theoretically predicted instability for rotational velocities exceeding some critical value. (author)

  5. Reversible micromachining locator

    Science.gov (United States)

    Salzer, L.J.; Foreman, L.R.

    1999-08-31

    This invention provides a device which includes a locator, a kinematic mount positioned on a conventional tooling machine, a part carrier disposed on the locator and a retainer ring. The locator has disposed therein a plurality of steel balls, placed in an equidistant position circumferentially around the locator. The kinematic mount includes a plurality of magnets which are in registry with the steel balls on the locator. In operation, a blank part to be machined is placed between a surface of a locator and the retainer ring (fitting within the part carrier). When the locator (with a blank part to be machined) is coupled to the kinematic mount, the part is thus exposed for the desired machining process. Because the locator is removably attachable to the kinematic mount, it can easily be removed from the mount, reversed, and reinserted onto the mount for additional machining. Further, the locator can likewise be removed from the mount and placed onto another tooling machine having a properly aligned kinematic mount. Because of the unique design and use of magnetic forces of the present invention, positioning errors of less than 0.25 micrometer for each machining process can be achieved. 7 figs.

  6. Driving Forward in Reverse

    International Nuclear Information System (INIS)

    We describe the use of TILLING in Lotus japonicus and the development of deletion (De)-TILLING in Medicago truncatula. The evolution of RevGen UK has been driven by the development of reverse genetics technologies in these two model legumes and Brassica rapa, which functions as a translational species for brassica crops. TILLING and De-TILLING are underpinned by populations of plants mutagenized with either EMS (that causes point mutations) or fast neutrons (that cause deletions), respectively. They permit the isolation of either allelic series of mutants or knockouts. Mutation detection will be developed from a number of independent gel-based systems to be carried out on a single platform - capillary electrophoresis. We are currently TILLING in both model legumes, but these developments will be applied to all three species. The resource will develop an open source database-driven system to support laboratory information management, analysis and the cataloguing of mutants in a genome context across all the species. (author)

  7. Technology of field reversed pinch

    International Nuclear Information System (INIS)

    This paper presents a review of field-reversed pinch technology. It covers the basic design requirements for various components involved in a field-reversed pinch device, such as circuit, switch, triggering system, transmission line, load assembly and power supply. Precautions against electric interferences are also mentioned

  8. What can be expected from NMR in reversed micelles?

    International Nuclear Information System (INIS)

    A review is given of NMR studies on reversed micellar systems since 1970. General principles are emphasized through examples which have led to relevant physico-chemical results in the area. NMR techniques or theories are not detailed in order to focus primarily on the information obtained on the micelles. (author). 50 refs.; 9 figs

  9. Parkinson's disease managing reversible neurodegeneration.

    Science.gov (United States)

    Hinz, Marty; Stein, Alvin; Cole, Ted; McDougall, Beth; Westaway, Mark

    2016-01-01

    Traditionally, the Parkinson's disease (PD) symptom course has been classified as an irreversible progressive neurodegenerative disease. This paper documents 29 PD and treatment-induced systemic depletion etiologies which cause and/or exacerbate the seven novel primary relative nutritional deficiencies associated with PD. These reversible relative nutritional deficiencies (RNDs) may facilitate and accelerate irreversible progressive neurodegeneration, while other reversible RNDs may induce previously undocumented reversible pseudo-neurodegeneration that is hiding in plain sight since the symptoms are identical to the symptoms being experienced by the PD patient. Documented herein is a novel nutritional approach for reversible processes management which may slow or halt irreversible progressive neurodegenerative disease and correct reversible RNDs whose symptoms are identical to the patient's PD symptoms. PMID:27103805

  10. Fundamentals of reversible flowchart languages

    DEFF Research Database (Denmark)

    Yokoyama, Tetsuo; Axelsen, Holger Bock; Glück, Robert

    2016-01-01

    Abstract This paper presents the fundamentals of reversible flowcharts. They are intended to naturally represent the structure and control flow of reversible (imperative) programming languages in a simple computation model, in the same way classical flowcharts do for conventional languages......, structured reversible flowcharts are as expressive as unstructured ones, as shown by a reversible version of the classic Structured Program Theorem. We illustrate how reversible flowcharts can be concretized with two example programming languages, complete with syntax and semantics: a low-level unstructured...... language and a high-level structured language. We introduce concrete tools such as program inverters and translators for both languages, which follow the structure suggested by the flowchart model. To further illustrate the different concepts and tools brought together in this paper, we present two major...

  11. Reversed polarity patches at the CMB and geomagnetic field reversal

    Institute of Scientific and Technical Information of China (English)

    XU; Wenyao(徐文耀); WEI; Zigang(魏自刚)

    2002-01-01

    The International Geomagnetic Reference Field models (IGRF) for 1900-2000 are used to calculate the geomagnetic field distribution in the Earth' interior from the ground surface to the core-mantle boundary (CMB) under the assumption of insulated mantle. Four reversed polarity patches, as one of the most important features of the CMB field, are revealed. Two patches with +Z polarity (downward) at the southern African and the southern American regions stand out against the background of -Z polarity (upward) in the southern hemisphere, and two patches of -Z polarity at the North Polar and the northern Pacific regions stand out against the +Z background in the northern hemisphere. During the 1900-2000 period the southern African (SAF) patch has quickly drifted westward at a speed of 0.2-0.3°/a; meanwhile its area has expanded 5 times, and the magnetic flux crossing the area has intensified 30 times. On the other hand, other three patches show little if any change during this 100-year period. Extending upward, each of the reversed polarity patches at the CMB forms a chimney-shaped "reversed polarity column" in the mantle with the bottom at the CMB. The height of the SAF column has grown rapidly from 200km in 1900 to 900km in 2000. If the column grows steadily at the same rate in the future, its top will reach to the ground surface in 600-700 years. And then a reversed polarity patch will be observed at the Earth's surface, which will be an indicator of the beginning of a magnetic field reversal. On the basis of this study, one can describe the process of a geomagnetic polarity reversal, the polarity reversal may be observed firstly in one or several local regions; then the areas of these regions expand, and at the same time, other new reversed polarity regions may appear. Thus several poles may exist during a polarity reversal.

  12. Reversible computing and cellular automata - A survey

    OpenAIRE

    Morita, Kenichi

    2008-01-01

    Reversible computing is a paradigm where computing models are defined so that they reflect physical reversibility, one of the fundamental microscopic physical property of Nature. In this survey/tutorial paper, we discuss how computation can be carried out in a reversible system, how a universal reversible computer can be constructed by reversible logic elements, and how such logic elements are related to reversible physical phenomena. We shall see that, in reversible systems, computation can ...

  13. 基于MCM-41微反应器的微波辅助合成新方法研究%Investigation on Novel Microwave-Assisted Synthesis Method Based on MCM-41 Microreactor

    Institute of Scientific and Technical Information of China (English)

    肖尚友; 杨昊书; 李倩倩; 邱静; 夏之宁

    2011-01-01

    MCM-41 mesoporous molecular sieve was synthesized under microwave irradiation and used as microreactor.2-Hydroxyphenylacetic acid was assembled into MCM-41 microreactor in toluene solution, and benzofuran-2(3H)-one was obtained by the intramolecular esterification of 2-hydroxyphenylacetic acid with high selectivity.The reaction conditions including temperature, reaction time, microwave irradiation and so on were investigated.The yield of benzofuran-2(3H)-one was improved by 2~12 and 2~33 times in MCM-41 microreactor than that in solution under conventional heating and microwave irradiation respectively.In addition, the yield of the reaction in MCM-41 reactor under microwave irradiation could be improved by 20%~ 100%.%采用微波辐射合成法合成了纳米介孔分子筛MCM-41作为微反应器.以苯并呋喃-2(3H)-酮的合成为实例,在甲苯介质中将邻羟基苯乙酸组装到MCM-41微反应器中,研究了溶液体系及微反应器中反应温度、反应时间及微波辐射时间对反应的影响.结果显示,在施加微波与不施加微波情况下,MCM-41微反应器中进行的反应较溶液体系中进行的反应产率提高了2~33与2~12倍.对于MCM-41微反应器中的反应,施加微波辐射后反应产率可进一步提高20%~100%.

  14. Application of Microreactor to the Preparation of C-11-Labeled Compounds via O-[11C]Methylation with [11C]CH3I: Rapid Synthesis of [11C]Raclopride.

    OpenAIRE

    Kawashima, Hidekazu; Kimura, Hiroyuki; Nakaya, Yuta; Tomatsu, Kenji; Arimitsu, Kenji; Nakanishi, Hiroaki; Ozeki, Eiichi; Kuge, Yuji; Saji, Hideo

    2015-01-01

    A new radiolabeling method using a microreactor was developed for the rapid synthesis of [(11)C]raclopride. A chip bearing a Y-shaped mixing junction with a 200 µm (width)×20 µm (depth)×250 mm (length) flow channel was designed, and the efficiency of O-[11C]methylation was evaluated. Dimethyl sulfoxide solutions containing the O-desmethyl precursor or [11C]CH3I were introduced into separate injection ports by infusion syringes, and the radiochemical yields were measured under various conditio...

  15. Plasma-assisted partial oxidation of methane at low temperatures: numerical analysis of gas-phase chemical mechanism

    Energy Technology Data Exchange (ETDEWEB)

    Goujard, Valentin; Nozaki, Tomohiro; Yuzawa, Shuhei; Okazaki, Ken [Department of Mechanical and Control Engineering, Tokyo Institute of Technology, 2-12-1 O-okayama, Meguro, 1528552, Tokyo (Japan); Agiral, Anil, E-mail: tnozaki@mech.titech.ac.jp [Mesoscale Chemical Systems, MESA Institute for Nanotechnology, Faculty of Science and Technology, University of Twente, PO Box 217, 7500 AE, Enschede (Netherlands)

    2011-07-13

    Methane partial oxidation was investigated using a plasma microreactor. The experiments were performed at 5 and 300 deg. C. Microreactor configuration allows an efficient evacuation of the heat generated by methane partial oxidation and dielectric barrier discharges, allowing at the same time a better temperature control. At 5 deg. C, liquid condensation of low vapour pressure compounds, such as formaldehyde and methanol, occurs. {sup 1}H-NMR analysis allowed us to demonstrate significant CH{sub 3}OOH formation during plasma-assisted partial oxidation of methane. Conversion and product selectivity were discussed for both temperatures. In the second part of this work, a numerical simulation was performed and a gas-phase chemical mechanism was proposed and discussed. From the comparison between the experimental results and the simulation it was found that CH{sub 3}OO{center_dot} formation has a determinant role in oxygenated compound production, since its fast formation disfavoured radical recombination. At 5 deg. C the oxidation leads mainly towards oxygenated compound formation, and plasma dissociation was the major phenomenon responsible for CH{sub 4} conversion. At 300 deg. C, higher CH{sub 4} conversion resulted from oxidative reactions induced by {center_dot}OH radicals with a chemistry predominantly oxidative, producing CO, H{sub 2}, CO{sub 2} and H{sub 2}O.

  16. Reverse engineering for quality systems

    International Nuclear Information System (INIS)

    When the age of software engineering began, many companies were faced with a problem of how to support the older, pre-software-engineering, programs. The techniques of reverse engineering and re-engineering were developed to bridge the gap between the past and the present. Although reverse engineering can be used for generating missing documentation, it can also be used as a means to demonstrate quality in these older programs. This paper presents, in the form of a case study, how Rolls-Royce and Associates Limited addressed the quality issues of reverse engineering and re-engineering. (author)

  17. Development of reversible strain gage

    International Nuclear Information System (INIS)

    A high-temperature strain gage which can be peeled after taking required apparent strain measurements in a furnace and can be attached reverse-side-up at the point of interest on a test structure was developed. Using the ''reversible'' strain gage with selected room-temperature curing type polyester adhesive, one can expect to measure thermal strain accurately, especially for on large structures, at the first test in temperature up to 250 deg C. The repeatability of apparent strains for about 100 reversible gages was within 50 microstrains of difference at 250 deg C (within 30 microstrains of difference for 80 % of the test gages). (author)

  18. Aminotroponiminates as tunable, redox-active ligands: reversible single electron transfer and reductive dimerisation.

    Science.gov (United States)

    Lichtenberg, C; Krummenacher, I

    2016-08-21

    Aminotroponiminates (atis) are shown to be redox-active ligands. Under strongly reducing conditions, the result of electron transfer can be controlled by the choice of the metal bound to the ati ligand. Either reversible electron transfer or a reductively induced dimerisation is observed. The latter reaction is (regio- and diastereo-) selective and chemically reversible. PMID:27452905

  19. Reverse Engineering Quantum Field Theory

    OpenAIRE

    Oeckl, Robert

    2012-01-01

    An approach to the foundations of quantum theory is advertised that proceeds by "reverse engineering" quantum field theory. As a concrete instance of this approach, the general boundary formulation of quantum theory is outlined.

  20. An Overview of Reverse Logistics

    Institute of Scientific and Technical Information of China (English)

    WANG Jia-xiang; HE Xin

    2005-01-01

    Until recently, investment in logistics has focused mainly on the flows from companies to markets. Growing concerns for the environment and conserving resources have created new logistical approaches to more effectively manage the distribution function, and make better use of the resources available to an organization. One such approach is reverse logistics, which uses various methods to give scope for a back-load of finished products, components, waste, reusable packing, etc. from consumer to manufacturer. Back-loads allow manufacturers to reduce costs by using the distribution vehicle's return journey to create income or added value. This basic concept is now being developed to create novel solutions to the problems of reducing pollution, costs and vehicle movements, whilst maintaining high customer service levels. In this paper, the idea of reverse logistics is presented; motivations for it are analyzed, several successful practices are demonstrated and some important truths regarding successful reverse logistics are identified, trend of reverse logistics is provided.

  1. Reverse Knowledge Transfer in MNEs

    DEFF Research Database (Denmark)

    Mudambi, Ram; Piscitello, Lucia; Rabbiosi, Larissa

    2014-01-01

    positive correlation with the extent of reverse knowledge transfers to the parent MNE. Relying on the headquarters-subsidiary view of the MNE, we argue that, beyond a point, increasing subsidiary innovativeness will be associated with lower reverse knowledge transfers. Further, we argue that this...... relationship is sensitive to the subsidiary entry mode. Using data from a sample of 293 Italian subsidiaries, we find strong support for our hypotheses. In particular, our results confirm that the effect of subsidiary innovativeness on reverse knowledge transfers displays an inverted-U shape, and that the...... curvilinearity is greater for greenfield entries relative to acquisition entries. The U-shaped relationship between subsidiary innovativeness and reverse knowledge transfers, as well as the sensitivity of this result to entry mode are important new findings in the literature on the role of subsidiaries in...

  2. Designing the Reverse Supply Chain

    DEFF Research Database (Denmark)

    Gobbi, Chiara

    2011-01-01

    supply chain. Research limitations/implications – The focus is restricted to the industry of electrical and electronic products. Practical implications – Based on the outcome of the study, managers are able to determine the basic prerequisites for the design of their reverse supply chains. Originality......Purpose – The purpose of this paper is to explore the impact of the product residual value (PRV) and the loss of value over time of returned products in the reverse supply chain configuration. It also examines whether or not the distinction of Fisher's functional and innovative products holds for...... the reverse supply chain. Design/methodology/approach – In order to identify the relevance of the Fisher model, the model needs to be recast in terms of PRV, which, in this context, is considered the independent variable in the reverse logistics arena. Products defined as innovative in Fisher...

  3. A Typology of Reverse Innovation

    DEFF Research Database (Denmark)

    von Zedtwitz, Max; Corsi, Simone; Søberg, Peder Veng;

    2015-01-01

    Reverse innovation commonly refers to an innovation initially launched in a developing country and later introduced to an advanced country. Adopting a linear innovation model with the four sequential phases of concept ideation, product development, primary target market introduction, and subsequent...... secondary market introduction, this study expands the espoused definition of reverse innovation beyond its market-introduction focus with reversals in the flow of innovation in the ideation and product development phases. Recognizing that each phase can take place in different geographical locations, the...... taking place in an emerging country. This analytical framework allows recasting of current research at the intersection between innovation and international business. Of the 10 reverse innovation flows, six are new and have not been covered in the literature to date. The study addresses questions of...

  4. Proceedings of the Interdisciplinary colloquium on reversibility

    International Nuclear Information System (INIS)

    This document contains the contributions to a colloquium, presented either in full text or as Power Point presentations. After an opening speech on decision reversibility of waste retrieval, the contributions respectively addressed: The charge taking ability, Proving and demonstrating reversibility, The issue of reversibility in an evolutional system in the case of CO2 geological disposal, Interactions between reversibility and disposal safety, Reversible disposal of radioactive wastes, Reversibility and retrievability within debates on decision-making about nuclear wastes in Finland and United Kingdom, The political qualities of technologies (irreversibility and reversibility in nuclear waste management), The contribution of economic analysis to the reversibility of nuclear waste disposal, The economic cost of reversibility, The appropriation of the notion of reversibility by the Andra, Arguments about the notion of reversibility, The notion of reversibility as a political symbol or actual concern, The project of document space 'ExploRe' (opened pluri-disciplinary exploration of reversibility), The participatory documentarisation at the service of reversibility. Posters addressed the following topics: Andra and reversibility, Reversibility, operational safety and long term safety in geological disposal, Andra's R and D in relationship the monitoring and survey of reversible disposal installations, Numerical simulation for the prediction and the analysis of disposal operation and aid-to-decision for its management, Demand of reversibility with respect to disposal progressive development, Taking reversibility into account for the complementarity between warehousing and storage

  5. Enzyme recovery using reversed micelles.

    OpenAIRE

    Dekker, M.

    1990-01-01

    The objective of this study was to develop a liquid-liquid extraction process for the recovery of extracellular enzymes. The potentials of reaching this goal by using reversed micelles in an organic solvent have been investigated.Reversed micelles are aggregates of surfactant molecules containing an inner core of water molecules, dispersed in a continuous organic solvent medium. The considerable biotechnological potential of these systems is derived principally from the ability of the water d...

  6. Laparoscopic reversal of Hartmann's procedure

    DEFF Research Database (Denmark)

    Svenningsen, Peter Olsen; Bulut, Orhan; Jess, Per

    2010-01-01

    A change in procedure from open to laparoscopic reversal of Hartmann's colostomy was implemented at our department between May 2005 and December 2008. The aim of the study was to investigate if this change was beneficial for the patients.......A change in procedure from open to laparoscopic reversal of Hartmann's colostomy was implemented at our department between May 2005 and December 2008. The aim of the study was to investigate if this change was beneficial for the patients....

  7. The multidimensional reverse Hardy inequalities

    Czech Academy of Sciences Publication Activity Database

    Gogatishvili, Amiran; Mustafayev, Rza

    2012-01-01

    Roč. 15, č. 1 (2012), s. 1-14. ISSN 1331-4343 R&D Projects: GA ČR GA201/08/0383 Institutional research plan: CEZ:AV0Z10190503 Keywords : multidimensional Hardy operator * Hardy inequality * reverse Hardy inequality Subject RIV: BA - General Math ematics Impact factor: 0.588, year: 2012 http://mia.ele- math .com/15-01/The-multidimensional-reverse-Hardy-inequalities

  8. Deciphering records of geomagnetic reversals

    Science.gov (United States)

    Valet, Jean-Pierre; Fournier, Alexandre

    2016-06-01

    Polarity reversals of the geomagnetic field are a major feature of the Earth's dynamo. Questions remain regarding the dynamical processes that give rise to reversals and the properties of the geomagnetic field during a polarity transition. A large number of paleomagnetic reversal records have been acquired during the past 50 years in order to better constrain the structure and geometry of the transitional field. In addition, over the past two decades, numerical dynamo simulations have also provided insights into the reversal mechanism. Yet despite the large paleomagnetic database, controversial interpretations of records of the transitional field persist; they result from two characteristics inherent to all reversals, both of which are detrimental to an ambiguous analysis. On the one hand, the reversal process is rapid and requires adequate temporal resolution. On the other hand, weak field intensities during a reversal can affect the fidelity of magnetic recording in sedimentary records. This paper is aimed at reviewing critically the main reversal features derived from paleomagnetic records and at analyzing some of these features in light of numerical simulations. We discuss in detail the fidelity of the signal extracted from paleomagnetic records and pay special attention to their resolution with respect to the timing and mechanisms involved in the magnetization process. Records from marine sediments dominate the database. They give rise to transitional field models that often lead to overinterpret the data. Consequently, we attempt to separate robust results (and their subsequent interpretations) from those that do not stand on a strong observational footing. Finally, we discuss new avenues that should favor progress to better characterize and understand transitional field behavior.

  9. Vasectomy reversal: a clinical update

    OpenAIRE

    Patel, Abhishek P; Smith, Ryan P.

    2016-01-01

    textabstractVasectomy is a safe and effective method of contraception used by 42-60 million men worldwide. Approximately 3%-6% of men opt for a vasectomy reversal due to the death of a child or divorce and remarriage, change in financial situation, desire for more children within the same marriage, or to alleviate the dreaded postvasectomy pain syndrome. Unlike vasectomy, vasectomy reversal is a much more technically challenging procedure that is performed only by a minority of urologists and...

  10. CEO Turnover in Reverse Splits

    OpenAIRE

    Li-Hsun Wang; Chu-Hsiung Lin; Hsien-Ming Chen

    2010-01-01

    This study examines the application of CEO turnover on reverse stock splits firms. Using Taiwanese samples, we find that non-CEO turnover firms receive negative long-term abnormal returns, and their financial performances continue to decline following reverse splits. These findings are consistent with prior studies. Contrarily, neither significantly negative long-term abnormal returns nor changes on financial performance were found for CEO turnover firms. This study concludes that applying CE...

  11. Reversals of the solar dipole

    OpenAIRE

    Moss, David; Kitchatinov, Leonid L.; Sokoloff, Dmitri

    2012-01-01

    During a solar magnetic field reversal the magnetic dipole moment does not vanish, but migrates between poles, in contradiction to the predictions of mean-field dynamo theory. We try to explain this as a consequence of magnetic fluctuations. We exploit the statistics of fluctuations to estimate observable signatures. Simple statistical estimates, taken with results from mean-field dynamo theory, suggest that a non-zero dipole moment may persist through a global field reversal. Fluctuations in...

  12. Garbage collection for reversible functional languages

    DEFF Research Database (Denmark)

    Mogensen, Torben Ægidius

    2015-01-01

    Reversible languages are programming languages where all programs can run both forwards and backwards. Reversible functional languages have been proposed that use symmetric pattern matching and data construction. To be reversible, these languages require linearity: Every variable must be used...

  13. Design of High speed Low Power Reversible Vedic multiplier and Reversible Divider

    OpenAIRE

    Srikanth G Department of Electronics & Communication Engineerig, Indur Institute of Engineering & Technology, Siddipet, Medak, JNTUH University, Telangana, India.; Nasam Sai Kumar

    2014-01-01

    This paper bring out a 32X32 bit reversible Vedic multiplier using "Urdhva Tiryakabhayam" sutra meaning vertical and crosswise, is designed using reversible logic gates, which is the first of its kind. Also in this paper we propose a new reversible unsigned division circuit. This circuit is designed using reversible components like reversible parallel adder, reversible left-shift register, reversible multiplexer, reversible n-bit register with parallel load line. The reversibl...

  14. Design of Reversible Random Access Memory

    OpenAIRE

    Mamun, Md. Selim Al; Hossain, Syed Monowar

    2013-01-01

    Reversible logic has become immensely popular research area and its applications have spread in various technologies for their low power consumption. In this paper we proposed an efficient design of random access memory using reversible logic. In the way of designing the reversible random access memory we proposed a reversible decoder and a write enable reversible master slave D flip-flop. All the reversible designs are superior in terms of quantum cost, delay and garbage outputs compared to ...

  15. Reversible reactions between pyrite and pyrrhotite in SO2

    Science.gov (United States)

    Hausen, D. M.

    1991-04-01

    Differential thermal analysis (DTA) of iron sulfides in inert atmospheres containing varying amounts of SO2 indicates temperature-dependent reversible reactions between pyrite and pyrrhotite in the range from 350°C to 520°C. Hexagonal pyrrhotite (troilite) and sulfur dioxide interact above 350°C to form pyrite and magnetite. Pyrite decomposes endothermically to pyrrhotite and sulfur above 520°C in the same atmosphere. The sulfurization of hexagonal pyrrhotite to pyrite has been investigated kinetically by DTA and confirmed by x-ray diffraction and wet chemical analyses. The reversibility of this pyrrhotite-pyrite reaction in a sulfur dioxide atmosphere merits further metallurgical consideration.

  16. Reversible reactions between pyrite and pyrrhotite in SO sub 2

    Energy Technology Data Exchange (ETDEWEB)

    Hausen, D.M. (Newmount Mining Co. (US))

    1991-04-01

    Differential thermal analysis (DTA) of iron sulfides in inert atmospheres containing varying amounts of SO{sub 2} indicates temperature-dependent reversible reactions between pyrite and pyrrhotite in the range from 350{degrees} C to 520{degrees} C. Hexagonal pyrrhotite (troilite) and sulfur dioxide interact above 350{degrees} C to form pyrite and magnetite. Pyrite decomposes endothermically to pyrrhotite and sulfur above 520{degrees} C in the same atmosphere. The sulfurization of hexagonal pyrrhotite to pyrite has been investigated kinetically by DTA and confirmed by x-ray diffraction and wet chemical analyses. This paper reports on reversibility of this pyrrhotite-pyrite reaction in a sulfur dioxide atmosphere.

  17. Preparation of Bone-like Hydroxyapatite via a Reverse Microemulsion

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Bone-like hydroxyapatite( HAp ) powders were synthesized using a reverse microemulsion method without further calcine processing. Synthesis conditions had significant effects on the formation of HAp. According to the results of XRD patterns and FTIR spectra, the obtained needle shape HAp powder with poorly crystallized and carbonate substitution was chemically and structurally similar to the human bone powders. The alkaline of emulsion was responsible for the obtained HAp without calcine route, and carbonate came from CO2 in air during preparation. By ultrasonic treatment, the morphology of HAp particles changed from spherical to needle shape for the reverse micelles broke up due to the high energy of ultrasonic.

  18. Nearly 1000 Protein Identifications from 50 ng of Xenopus laevis Zygote Homogenate Using Online Sample Preparation on a Strong Cation Exchange Monolith Based Microreactor Coupled with Capillary Zone Electrophoresis.

    Science.gov (United States)

    Zhang, Zhenbin; Sun, Liangliang; Zhu, Guijie; Cox, Olivia F; Huber, Paul W; Dovichi, Norman J

    2016-01-01

    A sulfonate-silica hybrid strong cation exchange monolith microreactor was synthesized and coupled to a linear polyacrylamide coated capillary for online sample preparation and capillary zone electrophoresis-tandem mass spectrometry (CZE-MS/MS) bottom-up proteomic analysis. The protein sample was loaded onto the microreactor in an acidic buffer. After online reduction, alkylation, and digestion with trypsin, the digests were eluted with 200 mM ammonium bicarbonate at pH 8.2 for CZE-MS/MS analysis using 1 M acetic acid as the background electrolyte. This combination of basic elution and acidic background electrolytes results in both sample stacking and formation of a dynamic pH junction. 369 protein groups and 1274 peptides were identified from 50 ng of Xenopus laevis zygote homogenate, which is comparable with an offline sample preparation method, but the time required for sample preparation was decreased from over 24 h to less than 40 min. Dramatically improved performance was produced by coupling the reactor to a longer separation capillary (∼100 cm) and a Q Exactive HF mass spectrometer. 975 protein groups and 3749 peptides were identified from 50 ng of Xenopus protein using the online sample preparation method. PMID:26670623

  19. Relationship between Thermodynamic Driving Force and One-Way Fluxes in Reversible Processes

    OpenAIRE

    Beard, Daniel A.; Qian, Hong

    2007-01-01

    Chemical reaction systems operating in nonequilibrium open-system states arise in a great number of contexts, including the study of living organisms, in which chemical reactions, in general, are far from equilibrium. Here we introduce a theorem that relates forward and reverse fluxes and free energy for any chemical process operating in a steady state. This relationship, which is a generalization of equilibrium conditions to the case of a chemical process occurring in a nonequilibrium steady...

  20. Reversals in nature and the nature of reversals

    CERN Document Server

    Stefani, F; Günther, U; Sorriso-Valvo, L; Xu, M; G\\"unther, Uwe; Gerbeth, Gunter; Sorriso-Valvo, Luca; Stefani, Frank; Xu, Mingtian

    2007-01-01

    The asymmetric shape of reversals of the Earth's magnetic field indicates a possible connection with relaxation oscillations as they were early discussed by van der Pol. A simple mean-field dynamo model with a spherically symmetric $\\alpha$ coefficient is analysed with view on this similarity, and a comparison of the time series and the phase space trajectories with those of paleomagnetic measurements is carried out. For highly supercritical dynamos a very good agreement with the data is achieved. Deviations of numerical reversal sequences from Poisson statistics are analysed and compared with paleomagnetic data. The role of the inner core is discussed in a spectral theoretical context and arguments and numerical evidence is compiled that the growth of the inner core might be important for the long term changes of the reversal rate and the occurrence of superchrons.