WorldWideScience

Sample records for optimizing airflow reversals

  1. Experimental Study on Airflow Reversal Within Bypass Branch During Mine Fire

    Institute of Scientific and Technical Information of China (English)

    周福宝; 王德明; 周延

    2001-01-01

    Based on the analysis of conditions for airflow reversal within a bypass branch, the airflow reversal phenomena were successfully simulated in the laboratory experiments. Data obtained indicate that airflow reversal within a bypass branch is mainly caused by fire pressure yielded in the combustion branch. In addition, the maximum reversal quantity of airflow occurs in step with the highest temperature of fire, the highest concentration of CO2 and the lowest concentration of O2. Moreover, the time that fire size reaches the maximum value corresponds to the time airflow reversal in the bypass branch is most possible. The results are of great significance for guiding rescue work to avoid airflow reversal.

  2. Optimal Determination of Respiratory Airflow Patterns Using a Nonlinear Multicompartment Model for a Lung Mechanics System

    Directory of Open Access Journals (Sweden)

    Hancao Li

    2012-01-01

    Full Text Available We develop optimal respiratory airflow patterns using a nonlinear multicompartment model for a lung mechanics system. Specifically, we use classical calculus of variations minimization techniques to derive an optimal airflow pattern for inspiratory and expiratory breathing cycles. The physiological interpretation of the optimality criteria used involves the minimization of work of breathing and lung volume acceleration for the inspiratory phase, and the minimization of the elastic potential energy and rapid airflow rate changes for the expiratory phase. Finally, we numerically integrate the resulting nonlinear two-point boundary value problems to determine the optimal airflow patterns over the inspiratory and expiratory breathing cycles.

  3. Optimal determination of respiratory airflow patterns using a nonlinear multicompartment model for a lung mechanics system.

    Science.gov (United States)

    Li, Hancao; Haddad, Wassim M

    2012-01-01

    We develop optimal respiratory airflow patterns using a nonlinear multicompartment model for a lung mechanics system. Specifically, we use classical calculus of variations minimization techniques to derive an optimal airflow pattern for inspiratory and expiratory breathing cycles. The physiological interpretation of the optimality criteria used involves the minimization of work of breathing and lung volume acceleration for the inspiratory phase, and the minimization of the elastic potential energy and rapid airflow rate changes for the expiratory phase. Finally, we numerically integrate the resulting nonlinear two-point boundary value problems to determine the optimal airflow patterns over the inspiratory and expiratory breathing cycles.

  4. Optimized damper control of pressure and airflow in ventilation systems

    DEFF Research Database (Denmark)

    Koulani, Chrysanthi Sofia; Hviid, Christian Anker; Terkildsen, Søren

    2014-01-01

    Conventional control strategies in variable air volume (VAV) ventilation systems do not take fully into advantage the potential energy savings since the system operation is based on maintaining a constant static pressure (CSP) set point in the main duct irrespective of the actual pressure demand....... The static pressure reset (SPR) control strategy can optimize the operation of the supply air fans by adjusting the pressure set point to be just enough to deliver the required airflow to the most critical zone. This study investigated the operation and energy savings potential of an SPR control algorithm...... by using the Simulink programming tool which is addon software to MATLAB mathematical programming language. A model of a VAV ventilation system was created in Simulink based on the International Building Physics Toolbox (IBPT); the IBPT thermal zone was remodelled in order to calculate dynamically...

  5. Variability and reversibility of the slow and forced vital capacity in chronic airflow obstruction.

    Science.gov (United States)

    Gove, R I; Shepherd, J; Burge, P S

    1987-04-01

    The variability of the forced (FVC) and slow vital capacity (SVC) manoeuvres were compared in 33 adult patients with chronic airflow obstruction. The reversibility of the two manoeuvres to nebulized salbutamol were compared in 18 of the patients. Both manoeuvres had equally small variances both before and after bronchodilator. The degree of reversibility of the FVC was however significantly greater (P less than 0.05) than the SVC. Although both measurements are equally variable, the FVC has a greater capacity for reversibility, which may have clinical significance.

  6. 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.

  7. 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.¬

  8. Clinical, Physiological and Radiological Features in Asthma with Incomplete Reversibility of Airflow Obstruction Compared with Those of COPD

    Directory of Open Access Journals (Sweden)

    Louis-Philippe Boulet

    1998-01-01

    Full Text Available OBJECTIVES: To compare clinical features, pulmonary function and high-resolution computed chest tomography (HRCT findings of asthmatic patients with a component of incomplete reversibility of airflow obstruction (AIRAO with those of patients with smoking-induced chronic obstructive pulmonary disease (COPD.

  9. Design and parametric optimization of thermal management of lithium-ion battery module with reciprocating air-flow

    Institute of Scientific and Technical Information of China (English)

    刘燕平; 欧阳陈志; 江清柏; 梁波

    2015-01-01

    Single cell temperature difference of lithium-ion battery (LIB) module will significantly affect the safety and cycle life of the battery. The reciprocating air-flow module created by a periodic reversal of the air flow was investigated in an effort to mitigate the inherent temperature gradient problem of the conventional battery system with a unidirectional coolant flow with computational fluid dynamics (CFD). Orthogonal experiment and optimization design method based on computational fluid dynamics virtual experiments were developed. A set of optimized design factors for the cooling of reciprocating air flow of LIB thermal management was determined. The simulation experiments show that the reciprocating flow can achieve good heat dissipation, reduce the temperature difference, improve the temperature homogeneity and effectively lower the maximal temperature of the modular battery. The reciprocating flow improves the safety, long-term performance and life span of LIB.

  10. Optimization of reversible sequential circuits

    CERN Document Server

    Sayem, Abu Sadat Md

    2010-01-01

    In recent years reversible logic has been considered as an important issue for designing low power digital circuits. It has voluminous applications in the present rising nanotechnology such as DNA computing, Quantum Computing, low power VLSI and quantum dot automata. In this paper we have proposed optimized design of reversible sequential circuits in terms of number of gates, delay and hardware complexity. We have designed the latches with a new reversible gate and reduced the required number of gates, garbage outputs, and delay and hardware complexity. As the number of gates and garbage outputs increase the complexity of reversible circuits, this design will significantly enhance the performance. We have proposed reversible D-latch and JK latch which are better than the existing designs available in literature.

  11. Optimized reversible binary-coded decimal adders

    DEFF Research Database (Denmark)

    Thomsen, Michael Kirkedal; Glück, Robert

    2008-01-01

    their design. The optimized 1-decimal BCD full-adder, a 13 × 13 reversible logic circuit, is faster, and has lower circuit cost and less garbage bits. It can be used to build a fast reversible m-decimal BCD full-adder that has a delay of only m + 17 low-power reversible CMOS gates. For a 32-decimal (128-bit...... in reversible logic design by drastically reducing the number of garbage bits. Specialized designs benefit from support by reversible logic synthesis. All circuit components required for optimizing the original design could also be synthesized successfully by an implementation of an existing synthesis algorithm...

  12. Optimized reversible BCD adder using new reversible logic gates

    CERN Document Server

    Bhagyalakshmi, H R

    2010-01-01

    Reversible logic has received great attention in the recent years due to their ability to reduce the power dissipation which is the main requirement in low power digital design. It has wide applications advanced computing, low power CMOS design, Optical information processing, DNA computing, bio information, quantum computation and nanotechnology. This paper presents an optimized reversible BCD adder using a new reversible gate. A comparative result is presented which shows that the proposed design is more optimized in terms of number of gates, number of garbage outputs and quantum cost than the existing designs.

  13. Rule-Based Optimization of Reversible Circuits

    CERN Document Server

    Arabzadeh, Mona; Zamani, Morteza Saheb

    2010-01-01

    Reversible logic has applications in various research areas including low-power design and quantum computation. In this paper, a rule-based optimization approach for reversible circuits is proposed which uses both negative and positive control Toffoli gates during the optimization. To this end, a set of rules for removing NOT gates and optimizing sub-circuits with common-target gates are proposed. To evaluate the proposed approach, the best-reported synthesized circuits and the results of a recent synthesis algorithm which uses both negative and positive controls are used. Our experiments reveal the potential of the proposed approach in optimizing synthesized circuits.

  14. Delay Reduction in Optimized Reversible Multiplier Circuit

    Directory of Open Access Journals (Sweden)

    Mohammad Assarian

    2012-01-01

    Full Text Available In this study a novel reversible multiplier is presented. Reversible logic can play a significant role in computer domain. This logic can be applied in quantum computing, optical computing processing, DNA computing, and nanotechnology. One condition for reversibility of a computable model is that the number of input equate with the output. Reversible multiplier circuits are the circuits used frequently in computer system. For this reason, optimization in one reversible multiplier circuit can reduce its volume of hardware on one hand and increases the speed in a reversible system on the other hand. One of the important parameters that optimize a reversible circuit is reduction of delays in performance of the circuit. This paper investigates the performance characteristics of the gates, the circuits and methods of optimizing the performance of reversible multiplier circuits. Results showed that reduction of the reversible circuit layers has lead to improved performance due to the reduction of the propagation delay between input and output period. All the designs are in the nanometric scales.

  15. Optimizing reversible simulation of injective functions

    DEFF Research Database (Denmark)

    Yokoyama, Tetsuo; Axelsen, Holger Bock; Glück, Robert

    2012-01-01

    Bennett showed that a clean reversible simulation of injective programs is possible without returning the input of a program as additional output. His method involves two computation and two uncomputation phases. This paper proposes an optimization of Bennett’s simulation that requires only half ......-coding program is further optimized by conserving the model over the text-generation phase. This paper may thus provide a newviewon developing efficient reversible simulations for a certain class of injective functions....

  16. Reverse Logistics: RFID the key to optimality

    Directory of Open Access Journals (Sweden)

    Rezwan Asif

    2011-07-01

    Full Text Available Purpose: The purpose of this paper is to find ways to reduce uncertainties in Reverse logistic supply chain (RLSC through the use of Radio-frequency identification (RFID technology.Design/methodology/approach: This paper reviews literature and builds model to relate RFID with uncertainties in order to optimize Reverse Logistics. Findings: RFID is really efficient to determine and detect quantity, variety and cycle times of returns; however it's not as convenient to determine quality of the returns. The collected information from RFID can be used to standardize the RLSC.Research limitations: Though it’s several and unique advantages some limitations of RFID have been identified in quality and processing sequence, collecting points and different standards, and in global usage.Originality/value: Previous studies in the area of Reverse Logistics and RFID don’t cover all impacts of this technology on RLSC. This review paper has investigated these impacts and offers a model for optimizing the Reverse Logistics Supply Chain.

  17. Reversible and quantum circuits optimization and complexity analysis

    CERN Document Server

    Abdessaied, Nabila

    2016-01-01

    This book presents a new optimization flow for quantum circuits realization. At the reversible level, optimization algorithms are presented to reduce the quantum cost. Then, new mapping approaches to decompose reversible circuits to quantum circuits using different quantum libraries are described. Finally, optimization techniques to reduce the quantum cost or the delay are applied to the resulting quantum circuits. Furthermore, this book studies the complexity of reversible circuits and quantum circuits from a theoretical perspective.

  18. Optimal Reverse Carpooling Over Wireless Networks - A Distributed Optimization Approach

    CERN Document Server

    ParandehGheibi, Ali; Effros, Michelle; Medard, Muriel

    2010-01-01

    We focus on a particular form of network coding, reverse carpooling, in a wireless network where the potentially coded transmitted messages are to be decoded immediately upon reception. The network is fixed and known, and the system performance is measured in terms of the number of wireless broadcasts required to meet multiple unicast demands. Motivated by the structure of the coding scheme, we formulate the problem as a linear program by introducing a flow variable for each triple of connected nodes. This allows us to have a formulation polynomial in the number of nodes. Using dual decomposition and projected subgradient method, we present a decentralized algorithm to obtain optimal routing schemes in presence of coding opportunities. We show that the primal sub-problem can be expressed as a shortest path problem on an \\emph{edge-graph}, and the proposed algorithm requires each node to exchange information only with its neighbors.

  19. Reverse convex problems: an approach based on optimality conditions

    Directory of Open Access Journals (Sweden)

    Ider Tseveendorj

    2006-01-01

    Full Text Available We present some results concerning reverse convex problems. Global optimality conditions for the problems with a nonsmooth reverse convex constraint are established and convergence of an algorithm in the case of linear program with an additional quadratic reverse convex constraint is studied.

  20. Reverse convex problems: an approach based on optimality conditions

    OpenAIRE

    Ider Tseveendorj

    2006-01-01

    We present some results concerning reverse convex problems. Global optimality conditions for the problems with a nonsmooth reverse convex constraint are established and convergence of an algorithm in the case of linear program with an additional quadratic reverse convex constraint is studied.

  1. Optimizing reversible simulation of injective functions

    DEFF Research Database (Denmark)

    Yokoyama, Tetsuo; Axelsen, Holger Bock; Glück, Robert

    2012-01-01

    of the computation and uncomputation steps for a class of injective programs. A practical consequence is that the reversible simulation runs twice as fast as Bennett’s simulation. The proposed method is demonstrated by developing lossless encoders and decoders for run-length encoding and range coding. The range...

  2. Depth-optimized reversible circuit synthesis

    Science.gov (United States)

    Arabzadeh, Mona; Saheb Zamani, Morteza; Sedighi, Mehdi; Saeedi, Mehdi

    2013-04-01

    In this paper, simultaneous reduction of circuit depth and synthesis cost of reversible circuits in quantum technologies with limited interaction is addressed. We developed a cycle-based synthesis algorithm which uses negative controls and limited distance between gate lines. To improve circuit depth, a new parallel structure is introduced in which before synthesis a set of disjoint cycles are extracted from the input specification and distributed into some subsets. The cycles of each subset are synthesized independently on different sets of ancillae. Accordingly, each disjoint set can be synthesized by different synthesis methods. Our analysis shows that the best worst-case synthesis cost of reversible circuits in the linear nearest neighbor architecture is improved by the proposed approach. Our experimental results reveal the effectiveness of the proposed approach to reduce cost and circuit depth for several benchmarks.

  3. Parametric Optimization Design of Brake Block Based on Reverse Engineering

    Directory of Open Access Journals (Sweden)

    Jin Hua-wei

    2017-01-01

    Full Text Available As one of the key part of automotive brake,the performance of brake block has a direct impact on the safety and comfort of cars. Modeling the brake block of disc brake in reverse parameterization by reverse engineering software, analyzing and optimizing the reconstructed model by CAE software. Processing the scanned point cloud by Geomagic Studio and reconstructing the CAD model of the brake block with the parametric surface function of the software, then analyzing and optimizing it by Wrokbench. The example shows that it is quick to reconstruct the CAD model of parts by using reverse parameterization method and reduce part re-design development cycle significantly.

  4. Optimization Approaches for Designing a Novel 4-Bit Reversible Comparator

    Science.gov (United States)

    Zhou, Ri-gui; Zhang, Man-qun; Wu, Qian; Li, Yan-cheng

    2013-02-01

    Reversible logic is a new rapidly developed research field in recent years, which has been receiving much attention for calculating with minimizing the energy consumption. This paper constructs a 4×4 new reversible gate called ZRQ gate to build quantum adder and subtraction. Meanwhile, a novel 1-bit reversible comparator by using the proposed ZRQC module on the basis of ZRQ gate is proposed as the minimum number of reversible gates and quantum costs. In addition, this paper presents a novel 4-bit reversible comparator based on the 1-bit reversible comparator. One of the vital important for optimizing reversible logic is to design reversible logic circuits with the minimum number of parameters. The proposed reversible comparators in this paper can obtain superiority in terms of the number of reversible gates, input constants, garbage outputs, unit delays and quantum costs compared with the existed circuits. Finally, MATLAB simulation software is used to test and verify the correctness of the proposed 4-bit reversible comparator.

  5. Airflow Simulation Techniques

    DEFF Research Database (Denmark)

    Nielsen, Peter V.

    The paper describes the development in airflow simulations in rooms . The research is, as other areas of flow research, influenced by the decreasing cost of computation which seems to indicate an increased use of airflow simulation in the coming years....

  6. Efficient Algorithms for Optimal 4-Bit Reversible Logic System Synthesis

    Directory of Open Access Journals (Sweden)

    Zhiqiang Li

    2013-01-01

    Full Text Available Owing to the exponential nature of the memory and run-time complexity, many methods can only synthesize 3-bit reversible circuits and cannot synthesize 4-bit reversible circuits well. We mainly absorb the ideas of our 3-bit synthesis algorithms based on hash table and present the efficient algorithms which can construct almost all optimal 4-bit reversible logic circuits with many types of gates and at mini-length cost based on constructing the shortest coding and the specific topological compression; thus, the lossless compression ratio of the space of n-bit circuits reaches near 2×n!. This paper presents the first work to create all 3120218828 optimal 4-bit reversible circuits with up to 8 gates for the CNT (Controlled-NOT gate, NOT gate, and Toffoli gate library, and it can quickly achieve 16 steps through specific cascading created circuits.

  7. Reverse electrodialysis : A validated process model for design and optimization

    NARCIS (Netherlands)

    Veerman, J.; Saakes, M.; Metz, S. J.; Harmsen, G. J.

    2011-01-01

    Reverse electrodialysis (RED) is a technology to generate electricity using the entropy of the mixing of sea and river water. A model is made of the RED process and validated experimentally. The model is used to design and optimize the RED process. It predicts very small differences between counter-

  8. OPTIMIZATION AND APPLICATIONS OF REVERSE-FLOW CYCLONES

    Institute of Scientific and Technical Information of China (English)

    Guogang Sun; Jianyi Chen; Mingxian Shi

    2005-01-01

    An optimum design approach to reverse-flow cyclones based on the concept of optimizing cyclone dimensions is introduced in this paper. This approach involves optimizing cyclone dimensions by categories, calculating cyclone performance by correlating similitude numbers and optimizing the combination of four cyclone parameters, D, KA,(-d- and vi, which has been proven to be applicable not only for single-stage cyclone, but also for multistage cyclone separators. Applications of the designed cyclones in FCC units and acrylonitrile reactors are also presented.

  9. Reversals and collisions optimize protein exchange in bacterial swarms

    Energy Technology Data Exchange (ETDEWEB)

    Amiri, Aboutaleb; Harvey, Cameron; Buchmann, Amy; Christley, Scott; Shrout, Joshua D.; Aranson, Igor S.; Alber, Mark

    2017-03-01

    Swarming groups of bacteria coordinate their behavior by self-organizing as a population to move over surfaces in search of nutrients and optimal niches for colonization. Many open questions remain about the cues used by swarming bacteria to achieve this self-organization. While chemical cue signaling known as quorum sensing is well-described, swarming bacteria often act and coordinate on time scales that could not be achieved via these extracellular quorum sensing cues. Here, cell-cell contact-dependent protein exchange is explored as amechanism of intercellular signaling for the bacterium Myxococcus xanthus. A detailed biologically calibrated computational model is used to study how M. xanthus optimizes the connection rate between cells and maximizes the spread of an extracellular protein within the population. The maximum rate of protein spreading is observed for cells that reverse direction optimally for swarming. Cells that reverse too slowly or too fast fail to spread extracellular protein efficiently. In particular, a specific range of cell reversal frequencies was observed to maximize the cell-cell connection rate and minimize the time of protein spreading. Furthermore, our findings suggest that predesigned motion reversal can be employed to enhance the collective behavior of biological synthetic active systems.

  10. Reversals and collisions optimize protein exchange in bacterial swarms

    Science.gov (United States)

    Amiri, Aboutaleb; Harvey, Cameron; Buchmann, Amy; Christley, Scott; Shrout, Joshua D.; Aranson, Igor S.; Alber, Mark

    2017-03-01

    Swarming groups of bacteria coordinate their behavior by self-organizing as a population to move over surfaces in search of nutrients and optimal niches for colonization. Many open questions remain about the cues used by swarming bacteria to achieve this self-organization. While chemical cue signaling known as quorum sensing is well-described, swarming bacteria often act and coordinate on time scales that could not be achieved via these extracellular quorum sensing cues. Here, cell-cell contact-dependent protein exchange is explored as a mechanism of intercellular signaling for the bacterium Myxococcus xanthus. A detailed biologically calibrated computational model is used to study how M. xanthus optimizes the connection rate between cells and maximizes the spread of an extracellular protein within the population. The maximum rate of protein spreading is observed for cells that reverse direction optimally for swarming. Cells that reverse too slowly or too fast fail to spread extracellular protein efficiently. In particular, a specific range of cell reversal frequencies was observed to maximize the cell-cell connection rate and minimize the time of protein spreading. Furthermore, our findings suggest that predesigned motion reversal can be employed to enhance the collective behavior of biological synthetic active systems.

  11. An Optimal Remanufacturing Centre Selection Algorithm for Reverse Logistics Alliance

    Directory of Open Access Journals (Sweden)

    Uzma Hameed

    2013-07-01

    Full Text Available Reverse logistics has been an emerging field both in academic as well as in applied research since last two decades because of increasing consumer awareness, legislative initiatives and profits associated with reuse of products or components. The costs associated with reverse logistics are usually high and these need to be minimized. The current study focuses on the formulation of alliance for cost reductions in reverse logistics. Remanufacturing, refurbishing, repair, cannibalization and reuse are the processes which add value to the reverse logistics system and are capable of converting it into a profitable venture. Used products contribute a cheaper source of components and spares required to remanufacture a product because of the less costs associated with the labor and material resources when compared with the manufacturing of new parts or products. When a defective part is removed from a product or assembly, it can be restored to its original state of functionality. Instead of purchasing a new, the same can be restored from repair/remanufacture centre just replacing defective part with a new part or spare. Furthermore, for manufacturers to reduce investments in reverse logistics, the formations of alliance and sharing of facilities for remanufacturing can lead to more profitability. In this study a focus has been made for the formation of remanufacturing alliance and an algorithm has been formulated for the selection of optimal remanufacturing center for the reverse logistics alliance. A case company has been selected from emerging Chinese electronic manufacturing industry. The case has been solved by using data set of the selected company with the help of formulated algorithm.

  12. 气流式水平姿态传感器仿真的优化%Simulation optimization of airflow level posture sensor

    Institute of Scientific and Technical Information of China (English)

    杨其锐; 朴林华

    2015-01-01

    利用FLUENT软件,采用功率替代温度的优化方法计算出气流式水平姿态传感器密闭腔体内的温度分布图,分别计算了传感器在不同倾角状态下和不同环境温度下密闭腔体内的温度场分布情况,计算和实验结果表明:气流式水平姿态传感器的两热敏电阻丝的温度差与倾角有很好的线性关系,它们之间的变化率为2.6183 K/(o);环境温度对传感器的两热敏电阻丝的温度差的影响也是有线性关系的,倾角为24o时它们之间的变化率为–0.1359 K/K,与实验结果有很好的相似度。%Optimization method of power replacing temperature was used to calculate the temperature distribution of the airflow level posture sensor in closed cavity. The temperature distribution of sensor in closed cavity was calculated at different inclination sensor status and under different environmental temperatures. The calculation and experimental results show that the temperature difference between two thermal resistance wires of airflow level posture sensor has good linear relationship with inclination, and the change rate is 2.618 3 K/(o). The effection of environmental temperature on the resistance difference about the sensors’ two thermal resistance wires also has a linear relationship. When the inclination is 24o, the change rate is –0.135 9 K/K. It has a good similarity with the experimental results.

  13. Impact of acoustic airflow on intrasinus drug deposition: New insights into the vibrating mode and the optimal acoustic frequency to enhance the delivery of nebulized antibiotic

    OpenAIRE

    2015-01-01

    International audience; Aim: We investigated the impact of vibrating acoustic airflow, the high frequency (f ≥ 100 Hz) and the low frequency (f ≤ 45 Hz) sound waves, on the enhancement of intrasinus drug deposition.Methods: 81mKr-gas ventilation study was performed in a plastinated human cast with and without the addition of vibrating acoustic airflow. Similarly, intrasinus drug deposition in a nasal replica using gentamicin as a marker was studied with and without the superposition of differ...

  14. Assessing multizone airflow software

    Energy Technology Data Exchange (ETDEWEB)

    Lorenzetti, D.M.

    2001-12-01

    Multizone models form the basis of most computer simulations of airflow and pollutant transport in buildings. In order to promote computational efficiency, some multizone simulation programs, such as COMIS and CONTAM, restrict the form that their flow models may take. While these tools allow scientists and engineers to explore a wide range of building airflow problems, increasingly their use has led to new questions not answerable by the current generation of programs. This paper, directed at software developers working on the next generation of building airflow models, identifies structural aspects of COMIS and related programs that prevent them from easily incorporating desirable new airflow models. The paper also suggests criteria for evaluating alternate simulation environments for future modeling efforts.

  15. PLAIN CASCADE RESEARCH ON A REVERSIBLE COMBINED BLADE

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    A new type fully reversible combined blade is presented, which can fully reverse airflow during the inverse ventilation by simply reversion. It is suitable for reversible axial flow fans used in tunnel and mine ventilation. The optimal parameters such as overlap ratio and pitch ratio are determined through cascade experiment. Experiment results also show a big promotion of maximum lift coefficient Cl,max and stall attack angle (l,max compared to the existing bi-directional symmetry airfoils.

  16. Optimization of membrane elements' array in industrial reverse osmosis units

    Science.gov (United States)

    Bobinkin, V. V.; Larionov, S. Yu.; Panteleev, A. A.; Shapovalov, D. A.; Shilov, M. M.

    2015-10-01

    It is stated that membrane elements, due to axial concentration and flow exhaustion during filtration, work in different operation conditions that differ according to various characteristics. Designing of multistage units is based on technical characteristics' identity of all membrane elements. It is explored that the difference in individual characteristics of membrane elements can take place. This can essentially affect the operation characteristics of a whole industrial unit. Particularly, it could lead to degradation of the permeate quality and the unit performance. Research on packaging the membrane elements in reverse osmosis units has shown that a simple replacement of membrane elements without the consideration of the individual characteristics can degrade the performance characteristics and affect the constancy of the unit operation. An optimization system of membrane elements' array was suggested to solve these problems and to upgrade the performance of reverse osmosis plants. The first step of the system is determination of individual characteristics of membrane elements. For the calculations using the individualized data, it is suggested to use the method of approximate calculation and the balance equations for water flows (source water, permeate, and retentate), and for the concentrations of the dissolved solids. The suggested optimization system of a membrane elements' array allowed the configuration of the membrane elements in the housings of one stage in such a way that the symmetry of the flows and of the pressure difference was achieved. The optimum value of the performance and the selectivity was achieved considering the hydraulic characteristics in one stage.

  17. Design and optimization of reverse-transcription quantitative PCR experiments.

    Science.gov (United States)

    Tichopad, Ales; Kitchen, Rob; Riedmaier, Irmgard; Becker, Christiane; Ståhlberg, Anders; Kubista, Mikael

    2009-10-01

    Quantitative PCR (qPCR) is a valuable technique for accurately and reliably profiling and quantifying gene expression. Typically, samples obtained from the organism of study have to be processed via several preparative steps before qPCR. We estimated the errors of sample withdrawal and extraction, reverse transcription (RT), and qPCR that are introduced into measurements of mRNA concentrations. We performed hierarchically arranged experiments with 3 animals, 3 samples, 3 RT reactions, and 3 qPCRs and quantified the expression of several genes in solid tissue, blood, cell culture, and single cells. A nested ANOVA design was used to model the experiments, and relative and absolute errors were calculated with this model for each processing level in the hierarchical design. We found that intersubject differences became easily confounded by sample heterogeneity for single cells and solid tissue. In cell cultures and blood, the noise from the RT and qPCR steps contributed substantially to the overall error because the sampling noise was less pronounced. We recommend the use of sample replicates preferentially to any other replicates when working with solid tissue, cell cultures, and single cells, and we recommend the use of RT replicates when working with blood. We show how an optimal sampling plan can be calculated for a limited budget. .

  18. On wind turbine power performance measurements at inclined airflow

    Science.gov (United States)

    Pedersen, T. F.

    2004-07-01

    The average airflow inclination in complex terrain may be substantial. The airflow inclination affects wind turbine performance and also affects the cup anemometer being used in power performance measurements. In this article the overall dependence of the power curve on inclined airflow is analysed for its influence on both the wind turbine and the cup anemometer. The wind turbine performance analysis is based on results of measurements and theoretical calculations with the aeroelastic code HAWC coupled to a 3D actuator disc model for varying yaw angle. The cup anemometer analysis at inclined flow is based on an averaging of measured angular characteristics in a wind tunnel with the distribution of airflow inclination angles over time. The relative difference in annual energy production in terrain with inclined airflow compared with flat terrain is simulated for cup anemometers with theoretical optimal angular characteristics for two different definitions of wind speed, as well as for five commercial cup anemometers with measured angular characteristics. Copyright

  19. Optimized parity preserving quantum reversible full adder/subtractor

    Science.gov (United States)

    Haghparast, Majid; Bolhassani, Ali

    2016-07-01

    Reversible logic is one of the indispensable aspects of emerging technologies for reducing physical entropy gain, since reversible circuits do not lose information in the form of internal heat during computation. This paper aimed to initiate constructing parity preserving reversible circuits. A novel parity preserving reversible block, HB is presented. Then a new design of a cost-effective parity preserving reversible full adder/subtractor (PPFA/S) is proposed. Next, we suggested a new parity preserving binary to BCD converter. Finally, we proposed new realization of parity preserving reversible BCD adder. The proposed designs are cost-effective in terms of quantum cost and delay. All the scales are in the NANO-metric area.

  20. Optimized Multiplier Using Reversible Multicontrol Input Toffoli Gates

    Directory of Open Access Journals (Sweden)

    H R Bhagyalakshmi

    2013-01-01

    Full Text Available Reversible logic is an important area to carry the computation into the world of quantum computing. In thispaper a 4-bit multiplier using a new reversible logic gate called BVPPG gate is presented. BVPPG gate isa 5 x 5 reversible gate which is designed to generate partial products required to perform multiplicationand also duplication of operand bits is obtained. This reduces the total cost of the circuit. Toffoli gate isthe universal and also most flexible reversible logic gate. So we have used the Toffoli gates to construct thedesigned multiplier.

  1. Airflow obstruction and exercise.

    Science.gov (United States)

    Cooper, Christopher B

    2009-03-01

    The primary abnormality in chronic obstructive pulmonary disease (COPD) is chronic airway inflammation which results in airflow limitation. Disease progression is usually depicted as an accelerated decline in FEV(1) over time. However, COPD patients also manifest progressive static hyperinflation due to the combined effects of reduced lung elastic recoil and increased airway resistance. Superimposed on static hyperinflation are further increases in operational lung volumes (dynamic hyperinflation) brought on during exercise, exacerbations or tachypnea. An important consequence of exertional dyspnea is activity limitation. COPD patients have been shown to spend only a third of the day walking or standing compared with age-matched healthy individuals who spend more than half of their time in these activities. Furthermore, the degree of activity limitation measured by an accelerometer worsens with disease progression. COPD patients have been shown to have an accelerated loss of aerobic capacity (VO(2)max) and this correlates with mortality just as is seen with hypertension, diabetes and obesity. Thus physical inactivity is an important therapeutic target in COPD. Summarizing; airflow obstruction leads to progressive hyperinflation, activity limitation, physical deconditioning and other comorbidities that characterize the COPD phenotype. Targeting the airflow obstruction with long-acting bronchodilator therapy in conjunction with a supervised exercise prescription is currently the most effective therapeutic intervention in earlier COPD. Other important manifestations of skeletal muscle dysfunction include muscle atrophy and weakness. These specific problems are best addressed with resistance training with consideration of anabolic supplementation.

  2. Optimized 4-bit Quantum Reversible Arithmetic Logic Unit

    Science.gov (United States)

    Ayyoub, Slimani; Achour, Benslama

    2017-08-01

    Reversible logic has received a great attention in the recent years due to its ability to reduce the power dissipation. The main purposes of designing reversible logic are to decrease quantum cost, depth of the circuits and the number of garbage outputs. The arithmetic logic unit (ALU) is an important part of central processing unit (CPU) as the execution unit. This paper presents a complete design of a new reversible arithmetic logic unit (ALU) that can be part of a programmable reversible computing device such as a quantum computer. The proposed ALU based on a reversible low power control unit and small performance parameters full adder named double Peres gates. The presented ALU can produce the largest number (28) of arithmetic and logic functions and have the smallest number of quantum cost and delay compared with existing designs.

  3. Optimization Approaches for Designing Quantum Reversible Arithmetic Logic Unit

    Science.gov (United States)

    Haghparast, Majid; Bolhassani, Ali

    2016-03-01

    Reversible logic is emerging as a promising alternative for applications in low-power design and quantum computation in recent years due to its ability to reduce power dissipation, which is an important research area in low power VLSI and ULSI designs. Many important contributions have been made in the literatures towards the reversible implementations of arithmetic and logical structures; however, there have not been many efforts directed towards efficient approaches for designing reversible Arithmetic Logic Unit (ALU). In this study, three efficient approaches are presented and their implementations in the design of reversible ALUs are demonstrated. Three new designs of reversible one-digit arithmetic logic unit for quantum arithmetic has been presented in this article. This paper provides explicit construction of reversible ALU effecting basic arithmetic operations with respect to the minimization of cost metrics. The architectures of the designs have been proposed in which each block is realized using elementary quantum logic gates. Then, reversible implementations of the proposed designs are analyzed and evaluated. The results demonstrate that the proposed designs are cost-effective compared with the existing counterparts. All the scales are in the NANO-metric area.

  4. Parallel Optimization of a Reversible (Quantum) Ripple-Carry Adder

    DEFF Research Database (Denmark)

    Thomsen, Michael Kirkedal; Axelsen, Holger Bock

    2008-01-01

    The design of fast arithmetic logic circuits is an important research topic for reversible and quantum computing. A special challenge in this setting is the computation of standard arithmetical functions without the generation of garbage. The CDKM-adder is a recent garbage-less reversible (quantum......(mk). We also show designs for garbage-less reversible set-less-than circuits. We compare the circuit costs of the CDKM and parallel adder in measures of circuit delay, width, gate and transistor count, and find that the parallelized adder offers significant speedups at realistic word sizes with modest...

  5. Describing and optimizing reversible logic using a functional language

    DEFF Research Database (Denmark)

    Thomsen, Michael Kirkedal

    2012-01-01

    This paper presents the design of a language for the description and optimisation of reversible logic circuits. The language is a combinator-style functional language designed to be close to the reversible logical gate-level. The combinators include high-level constructs such as ripples, but also...... the recognisable inversion combinator f^(-1), which defines the inverse function of f using an efficient semantics. It is important to ensure that all circuits descriptions are reversible, and furthermore we must require this to be done statically. This is en- sured by the type system, which also allows...... the description of arbitrary sized circuits. The combination of the functional language and the restricted reversible model results in many arithmetic laws, which provide more possibilities for term rewriting and, thus, the opportunity for good optimisation....

  6. Optimized design of BCD adder and Carry skip BCD adder using reversible logic gates

    OpenAIRE

    H.R.Bhagyalakshmi,; M K Venkatesha

    2011-01-01

    Reversible logic is very essential for the construction of low power, low loss computational structures which are very essential for the construction of arithmetic circuits used in quantum computation, nano technology and other low power digital circuits. In the present paper an optimized and low quantum cost one digit BCD adder and an optimized one digit carry skip BCD adder using new reversible logic gates are proposed. The proposed work is best compared to the other existing circuits.

  7. Optimized design of BCD adder and Carry skip BCD adder using reversible logic gates

    Directory of Open Access Journals (Sweden)

    H.R.Bhagyalakshmi,

    2011-04-01

    Full Text Available Reversible logic is very essential for the construction of low power, low loss computational structures which are very essential for the construction of arithmetic circuits used in quantum computation, nano technology and other low power digital circuits. In the present paper an optimized and low quantum cost one digit BCD adder and an optimized one digit carry skip BCD adder using new reversible logic gates are proposed. The proposed work is best compared to the other existing circuits.

  8. Time Reversal Reconstruction Algorithm Based on PSO Optimized SVM Interpolation for Photoacoustic Imaging

    Directory of Open Access Journals (Sweden)

    Mingjian Sun

    2015-01-01

    Full Text Available Photoacoustic imaging is an innovative imaging technique to image biomedical tissues. The time reversal reconstruction algorithm in which a numerical model of the acoustic forward problem is run backwards in time is widely used. In the paper, a time reversal reconstruction algorithm based on particle swarm optimization (PSO optimized support vector machine (SVM interpolation method is proposed for photoacoustics imaging. Numerical results show that the reconstructed images of the proposed algorithm are more accurate than those of the nearest neighbor interpolation, linear interpolation, and cubic convolution interpolation based time reversal algorithm, which can provide higher imaging quality by using significantly fewer measurement positions or scanning times.

  9. Optimal Time-Reversed Wideband Signals for Distributed Sensing

    CERN Document Server

    Kim, Jerry; Mokole, Eric

    2015-01-01

    This paper considers a distributed wave-based sensing system that probes a scene consisting of multiple interacting idealized targets. Each sensor is a collocated transmit-receive pair that is capable of transmitting arbitrary wideband waveforms. We address the problem of finding the space-time transmit waveform that provides the best target detection performance in the sense of maximizing the energy scattered back into the receivers. Our approach is based on earlier work that constructed the solution by an iterative time-reversal (TR) process. In particular, for the case of idealized point-like scatterers in free space, we examine the frequency dependence of the eigenvalues of the TR operator, and we show that their behavior depends on constructive and destructive interference of the waves traveling along different paths. In addition, we show how these eigenvalues are connected to the poles of the Singularity Expansion Method. Our study of the frequency behavior distinguishes this work from most previous TR ...

  10. Optimized design of Carry Skip BCD adder using new FHNG reversible logic gates

    Directory of Open Access Journals (Sweden)

    Md.Belayet Ali

    2012-07-01

    Full Text Available Reversible logic is very essential for the construction of low power, low loss computational structures which are very essential for the construction of arithmetic circuits used in quantum computation, nanotechnology and other low power digital circuits. In the present paper an optimized and low quantum cost one digit carry skip BCD adder using new reversible logic gates are proposed. The proposed work is best compared to the other existing circuits.

  11. Implementation of Optimized Reversible Sequential and Combinational Circuits for VLSI Applications

    Directory of Open Access Journals (Sweden)

    P. Mohan Krishna

    2014-04-01

    Full Text Available Reversible logic has emerged as one of the most important approaches for the power optimization with its application in low power VLSI design. They are also the fundamental requirement for the emerging field of the Quantum computing having with applications in the domains like Nano-technology, Digital signal processing, Cryptography, Communications. Implementing the reversible logic has the advantages of reducing gate counts, garbage outputs as well as constant inputs. In this project we present sequential and combinational circuit with reversible logic gates which are simulated in Xilinx ISE and by writing the code in VHDL . we have proposed a new design technique of BCD Adder using newly constructed reversible gates are based on CMOS with pass transistor gates . Here the total reversible Adder is designed using EDA tools. We will analyze the VLSI limitations like power consumption and area of designed circuits.

  12. Optimal manufacturing and remanufacturing capacities of systems with reverse logistics and deterministic uniform demand

    Directory of Open Access Journals (Sweden)

    Ernest Benedito

    2010-06-01

    Full Text Available Using reverse logistics in production systems can help to reduce costs. However, it can also mean introducing a source of uncertainty in the system behavior. In this study we present a method for calculating the optimal manufacturing and remanufacturing capacities of a system with reverse logistics and steady demand taking into account the random behavior of the quantity, quality and timing of units that are collected thru the reverse logistics system. The collected units are remanufactured or disposed of. We also provide an example to illustrate the method.

  13. Minimum airflow reset of single-duct VAV terminal boxes

    Science.gov (United States)

    Cho, Young-Hum

    Single duct Variable Air Volume (VAV) systems are currently the most widely used type of HVAC system in the United States. When installing such a system, it is critical to determine the minimum airflow set point of the terminal box, as an optimally selected set point will improve the level of thermal comfort and indoor air quality (IAQ) while at the same time lower overall energy costs. In principle, this minimum rate should be calculated according to the minimum ventilation requirement based on ASHRAE standard 62.1 and maximum heating load of the zone. Several factors must be carefully considered when calculating this minimum rate. Terminal boxes with conventional control sequences may result in occupant discomfort and energy waste. If the minimum rate of airflow is set too high, the AHUs will consume excess fan power, and the terminal boxes may cause significant simultaneous room heating and cooling. At the same time, a rate that is too low will result in poor air circulation and indoor air quality in the air-conditioned space. Currently, many scholars are investigating how to change the algorithm of the advanced VAV terminal box controller without retrofitting. Some of these controllers have been found to effectively improve thermal comfort, indoor air quality, and energy efficiency. However, minimum airflow set points have not yet been identified, nor has controller performance been verified in confirmed studies. In this study, control algorithms were developed that automatically identify and reset terminal box minimum airflow set points, thereby improving indoor air quality and thermal comfort levels, and reducing the overall rate of energy consumption. A theoretical analysis of the optimal minimum airflow and discharge air temperature was performed to identify the potential energy benefits of resetting the terminal box minimum airflow set points. Applicable control algorithms for calculating the ideal values for the minimum airflow reset were developed and

  14. Optimal One Bit Time Reversal For UWB Impulse Radio In Multi-User Wireless Communications

    DEFF Research Database (Denmark)

    Nguyen, Hung Tuan

    2008-01-01

    In this paper, with the purpose of further reducing the complexity of the system, while keeping its temporal and spatial focusing performance, we investigate the possibility of using optimal one bit time reversal (TR) system for impulse radio ultra wideband multi-user wireless communications...

  15. Two-step optimization of pressure and recovery of reverse osmosis desalination process.

    Science.gov (United States)

    Liang, Shuang; Liu, Cui; Song, Lianfa

    2009-05-01

    Driving pressure and recovery are two primary design variables of a reverse osmosis process that largely determine the total cost of seawater and brackish water desalination. A two-step optimization procedure was developed in this paper to determine the values of driving pressure and recovery that minimize the total cost of RO desalination. It was demonstrated that the optimal net driving pressure is solely determined by the electricity price and the membrane price index, which is a lumped parameter to collectively reflect membrane price, resistance, and service time. On the other hand, the optimal recovery is determined by the electricity price, initial osmotic pressure, and costs for pretreatment of raw water and handling of retentate. Concise equations were derived for the optimal net driving pressure and recovery. The dependences of the optimal net driving pressure and recovery on the electricity price, membrane price, and costs for raw water pretreatment and retentate handling were discussed.

  16. Airflow Actuation of Shortfin Mako Shark Denticles

    Science.gov (United States)

    Devey, Sean; Hubner, Paul; Lang, Amy

    2016-11-01

    The shortfin mako shark is covered in microscopic scales called denticles, which may act as a mechanism for passive flow control. Recent research has investigated the theory that reversing flow could passively bristle these denticles, which could delay flow separation. Water tunnel studies have supported this theory, yet a wind tunnel study at a greater dynamic pressure found no significant differences between an airfoil covered with mako skin and a smooth airfoil. A likely cause is that surface tension between denticles, which must be wet to retain flexibility, prevented bristling. This would not be an issue in water. To determine what reverse airflow characteristics cause denticle bristling in air, a benchtop study was conducted in which a jet of air was impinged upon a sample of wet mako skin in the reverse flow direction. A microscope and camera captured video of the denticles under the air jet, and image analysis techniques were used to detect bristling. Analysis shows sporadic bristling around 16 m/s (q = 150 Pa) but full bristling does not occur until above 35 m/s (q = 740 Pa). The free stream velocities required to achieve such reversal speeds are much higher. For this reason, mechanical analogues will be used rather than real skin in future studies of this mechanism. Funding from Boeing and NSF REU site Grant EEC 1358991 is greatly appreciated.

  17. A fuzzy multi-objective optimization model for sustainable reverse logistics network design

    DEFF Research Database (Denmark)

    Govindan, Kannan; Paam, Parichehr; Abtahi, Amir Reza

    2016-01-01

    a multi-echelon multi-period multi-objective model for a sustainable reverse logistics network. To reflect all aspects of sustainability, we try to minimize the present value of costs, as well as environmental impacts, and optimize the social responsibility as objective functions of the model. In order......Decreasing the environmental impact, increasing the degree of social responsibility, and considering the economic motivations of organizations are three significant features in designing a reverse logistics network under sustainability respects. Developing a model, which can simultaneously consider...

  18. RO-75: a FORTRAN code for calculation and design optimization of reverse osmosis seawater desalination plants

    Energy Technology Data Exchange (ETDEWEB)

    Glueckstern, P.; Reed, S.A.; Wilson, J.V.

    1976-11-01

    The reverse osmosis process has been used extensively for the conversion of brackish waters to potable water. The process is now nearing commercialization as a means for the conversion of seawater. The computer program (RO-75) is a Fortran code for the optimizatin of the design and economics of seawater reverse osmosis plants. The examples described are based on currently available, commercial membrane modules and prevailing prices. However, the code is very flexible and can be used to optimize plants utilizing future technological improvements and different economic parameters.

  19. Time reversal versus adaptive optimization for spatiotemporal nanolocalization in a random nanoantenna

    Science.gov (United States)

    Differt, Dominik; Hensen, Matthias; Pfeiffer, Walter

    2016-05-01

    Spatiotemporal nanolocalization of ultrashort pulses in a random scattering nanostructure via time reversal and adaptive optimization employing a genetic algorithm and a suitably defined fitness function is studied for two embedded nanoparticles that are separated by only a tenth of the free space wavelength. The nanostructure is composed of resonant core-shell nanoparticles (TiO2 core and Ag shell) placed randomly surrounding these two nanoparticles acting as targets. The time reversal scheme achieves selective nanolocalization only by chance if the incident radiation can couple efficiently to dipolar local modes interacting with the target/emitter particle. Even embedding the structure in a reverberation chamber fails improving the nanolocalization. In contrast, the adaptive optimization strategy reliably yields nanolocalization of the radiation and allows a highly selective excitation of either target position. This demonstrates that random scattering structures are interesting multi-purpose optical nanoantennas to realize highly flexible spatiotemporal optical near-field control.

  20. Evacuation Network Optimization Model with Lane-Based Reversal and Routing

    Directory of Open Access Journals (Sweden)

    Xing Zhao

    2016-01-01

    Full Text Available Sometimes, the evacuation measure may seem to be the best choice as an emergency response. To enable an efficiency evacuation, a network optimization model which integrates lane-based reversal design and routing with intersection crossing conflict elimination for evacuation is constructed. The proposed bilevel model minimizes the total evacuation time to leave the evacuation zone. A tabu search algorithm is applied to find an optimal lane reversal plan in the upper-level. The lower-level utilizes a simulated annealing algorithm to get two types of “a single arc for an intersection approach” and “multiple arcs for an intersection approach” lane-based route plans with intersection crossing conflict elimination. An experiment of a nine-intersection evacuation zone illustrates the validity of the model and the algorithm. A field case with network topology of Jianye District around the Nanjing Olympics Sports Center is studied to show the applicability of this algorithm.

  1. EP-based Optimization of Strategic Safety Stocks in Reverse Logistics Systems

    Institute of Scientific and Technical Information of China (English)

    LI Jun; WANG Ji-rong; HU Zong-wu; ZHANG Ji-hui

    2004-01-01

    A new heuristic strategic safety stock optimization is proposed based on evolutionary programming(EP) algorithm for reverse logistics supply chain systems. The supply chain is described with a network and the modeling complexity of external as well as internal product returns and reuses of supply chains is considered with. It is assumed that customer demands for final products are uncertain. Products are randomly returned from external customers to stock points. The optimization model is established and three different cases with different structures are used to show the strength of the algorithm.

  2. Reverse Chromatic Aberration and its Numerical Optimization in a Metamaterial Lens

    OpenAIRE

    Capecchi, W. J.; Behdad, N.; Volpe, F. A.

    2013-01-01

    In planar metamaterial lenses, the focal point moves with the frequency. Here it is shown numerically that this movement can be controlled by properly engineering the dimensions of the metamaterial-based phase shifters that constitute the lens. In particular, such lenses can be designed to exhibit unusual chromatic aberration with the focal length increasing, rather than decreasing, with the frequency. It is proposed that such an artificial "reverse" chromatic aberration may optimize the tran...

  3. Evolving neural network optimization of cholesteryl ester separation by reversed-phase HPLC

    OpenAIRE

    Jansen, Michael A.; Kiwata, Jacqueline; Arceo, Jennifer; Faull, Kym F.; Hanrahan, Grady; Porter, Edith

    2010-01-01

    Cholesteryl esters have antimicrobial activity and likely contribute to the innate immunity system. Improved separation techniques are needed to characterize these compounds. In this study, optimization of the reversed-phase high-performance liquid chromatography separation of six analyte standards (four cholesteryl esters plus cholesterol and tri-palmitin) was accomplished by modeling with an artificial neural network–genetic algorithm (ANN-GA) approach. A fractional factorial design was emp...

  4. Design Principles of Biological Oscillators through Optimization: Forward and Reverse Analysis

    Science.gov (United States)

    Otero-Muras, Irene; Banga, Julio R.

    2016-01-01

    From cyanobacteria to human, sustained oscillations coordinate important biological functions. Although much has been learned concerning the sophisticated molecular mechanisms underlying biological oscillators, design principles linking structure and functional behavior are not yet fully understood. Here we explore design principles of biological oscillators from a multiobjective optimization perspective, taking into account the trade-offs between conflicting performance goals or demands. We develop a comprehensive tool for automated design of oscillators, based on multicriteria global optimization that allows two modes: (i) the automatic design (forward problem) and (ii) the inference of design principles (reverse analysis problem). From the perspective of synthetic biology, the forward mode allows the solution of design problems that mimic some of the desirable properties appearing in natural oscillators. The reverse analysis mode facilitates a systematic exploration of the design space based on Pareto optimality concepts. The method is illustrated with two case studies: the automatic design of synthetic oscillators from a library of biological parts, and the exploration of design principles in 3-gene oscillatory systems. PMID:27977695

  5. Exergetic efficiency optimization for an irreversible heat pump working on reversed Brayton cycle

    Indian Academy of Sciences (India)

    Yuehong Bi; Lingen Chen; Fengrui Sun

    2010-03-01

    This paper deals with the performance analysis and optimization for irreversible heat pumps working on reversed Brayton cycle with constant-temperature heat reservoirs by taking exergetic efficiency as the optimization objective combining exergy concept with finite-time thermodynamics (FTT). Exergetic efficiency is defined as the ratio of rate of exergy output to rate of exergy input of the system. The irreversibilities considered in the system include heat resistance losses in the hot- and cold-side heat exchangers and non-isentropic losses in the compression and expansion processes. The analytical formulas of the heating load, coefficient of performance (COP) and exergetic efficiency for the heat pumps are derived. The results are compared with those obtained for the traditional heating load and coefficient of performance objectives. The influences of the pressure ratio of the compressor, the allocation of heat exchanger inventory, the temperature ratio of two reservoirs, the effectiveness of the hot- and cold-side heat exchangers and regenerator, the efficiencies of the compressor and expander, the ratio of hot-side heat reservoir temperature to ambient temperature, the total heat exchanger inventory, and the heat capacity rate of the working fluid on the exergetic efficiency of the heat pumps are analysed by numerical calculations. The results show that the exergetic efficiency optimization is an important and effective criterion for the evaluation of an irreversible heat pump working on reversed Brayton cycle.

  6. Application of statistical design for the optimization of amino acid separation by reverse-phase HPLC.

    Science.gov (United States)

    Gheshlaghi, R; Scharer, J M; Moo-Young, M; Douglas, P L

    2008-12-01

    Modified resolution and overall separation factors used to quantify the separation of complex chromatography systems are described. These factors were proven to be applicable to the optimization of amino acid resolution in reverse-phase (RP) HPLC chromatograms. To optimize precolumn derivatization with phenylisothiocyanate, a 2(5-1) fractional factorial design in triplicate was employed. The five independent variables for optimizing the overall separation factor were triethylamine content of the aqueous buffer, pH of the aqueous buffer, separation temperature, methanol/acetonitrile concentration ratio in the organic eluant, and mobile phase flow rate. Of these, triethylamine concentration and methanol/acetonitrile concentration ratio were the most important. The methodology captured the interaction between variables. Temperature appeared in the interaction terms; consequently, it was included in the hierarchic model. The preliminary model based on the factorial experiments was not able to explain the response curvature in the design space; therefore, a central composite design was used to provide a quadratic model. Constrained nonlinear programming was used for optimization purposes. The quadratic model predicted the optimal levels of the variables. In this study, the best levels of the five independent variables that provide the maximum modified resolution for each pair of consecutive amino acids appearing in the chromatograph were determined. These results are of utmost importance for accurate analysis of a subset of amino acids.

  7. Effect of airflow on nanofiber yarn spinning

    Directory of Open Access Journals (Sweden)

    He Jian-Xin

    2015-01-01

    Full Text Available The paper proposes a new air-jet spinning method for the preparation of continuous twisted nanofiber yarns. The nozzle-twisting device is designed to create the 3-D rotating airflow to twist nanofiber bundles. The airflow characteristics inside the twisting chamber are studied numerically. The airflow field distribution and its effect on nanofiber yarn spinning at different pressures are also discussed.

  8. Reverse chromatic aberration and its numerical optimization in a metamaterial lens.

    Science.gov (United States)

    Capecchi, William J; Behdad, Nader; Volpe, Francesco A

    2012-04-09

    In planar metamaterial lenses, the focal point moves with the frequency. Here it is shown numerically that this movement can be controlled by properly engineering the dimensions of the metamaterial-based phase shifters that constitute the lens. In particular, such lenses can be designed to exhibit unusual chromatic aberration with the focal length increasing, rather than decreasing, with the frequency. It is proposed that such an artificial "reverse" chromatic aberration may optimize the transverse resolution of millimeter wave diagnostics of plasmas and be useful in compensating for the natural "ordinary" chromatic aberration of other components in an optical system. More generally, optimized chromatic aberration will allow for simultaneous focusing of several objects located at different distances and emitting or reflecting at different frequencies.

  9. Reverse Chromatic Aberration and its Numerical Optimization in a Metamaterial Lens

    CERN Document Server

    Capecchi, W J; Volpe, F A; 10.1364/OE.20.008761

    2013-01-01

    In planar metamaterial lenses, the focal point moves with the frequency. Here it is shown numerically that this movement can be controlled by properly engineering the dimensions of the metamaterial-based phase shifters that constitute the lens. In particular, such lenses can be designed to exhibit unusual chromatic aberration with the focal length increasing, rather than decreasing, with the frequency. It is proposed that such an artificial "reverse" chromatic aberration may optimize the transverse resolution of millimeter wave diagnostics of plasmas and be useful in compensating for the natural "ordinary" chromatic aberration of other components in an optical system. More generally, optimized chromatic aberration will allow to simultaneously focus on several objects located at different distances and emitting or reflecting at different frequencies.

  10. Full 3-D viscous optimization design of a reversible pump turbine runner

    Science.gov (United States)

    Wang, X. H.; Zhu, B. S.; Cao, S. L.; Tan, L.

    2013-12-01

    The bi-directional operation of reversible pump turbines presents a great challenge in terms of runner design. In the present paper, an optimal design system for the pump turbine runner is presented by coupling three-dimensional (3-D) inverse design with the Computational Fluid Dynamics (CFD), Design of Experiment (DoE), Response Surface Methodology (RSM) and Multi Objective Genetic Algorithm (MOGA). A pump-turbine runner was designed using the system, with selecting blade loading distributions and blade lean as the input parameters, and the runner efficiency for both pump and turbine mode as optimization objectives. The CFD results show that a high efficiency runner can be designed using the present system.

  11. Shape Optimization of Three-Way Reversing Valve for Cavitation Reduction

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Myeong Gon; Han, Seung Ho [Donga Univ., Busan (Korea, Republic of); Lim, Cha Suk [Baek San Hi-Tech Co., Ltd., Seoul (Korea, Republic of)

    2015-11-15

    A pair of two-way valves typically is used in automotive washing machines, where the water flow direction is frequently reversed and highly pressurized clean water is sprayed to remove the oil and dirt remaining on machined engine and transmission blocks. Although this valve system has been widely used because of its competitive price, its application is sometimes restricted by surging effects, such as pressure ripples occurring in rapid changes in water flow caused by inaccurate valve control. As an alternative, one three-way reversing valve can replace the valve system because it provides rapid and accurate changes to the water flow direction without any precise control device. However, a cavitation effect occurs because of the complicated bottom plug shape of the valve. In this study, the cavitation index and percent of cavitation (POC) were introduced to numerically evaluate fluid flows via computational fluid dynamics (CFD) analysis. To reduce the cavitation effect generated by the bottom plug, the optimal shape design was carried out through a parametric study, in which a simple computer-aided engineering (CAE) model was applied to avoid time consuming CFD analysis and difficulties in achieving convergence. The optimal shape design process using full factorial design of experiments (DOEs) and an artificial neural network meta-model yielded the optimal waist and tail length of the bottom plug with a POC value of less than 30%, which meets the requirement of no cavitation occurrence. The optimal waist length, tail length and POC value were found to 6.42 mm, 6.96 mm and 27%, respectively.

  12. Shape optimization of three-way reversing valve for cavitation reduction

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Myeong Gon; Han, Seung Ho [Dept. of Mechanical Engineering, Dong-A University, Busan (Korea, Republic of); Lim, Cha Suk [Baek San Hi-Tech Co., Ltd., Yangsan(Korea, Republic of)

    2015-11-15

    A pair of two-way valves typically is used in automotive washing machines, where the water flow direction is frequently reversed and highly pressurized clean water is sprayed to remove the oil and dirt remaining on machined engine and transmission blocks. Although this valve system has been widely used because of its competitive price, its application is sometimes restricted by surging effects, such as pressure ripples occurring in rapid changes in water flow caused by inaccurate valve control. As an alternative, one three-way reversing valve can replace the valve system because it provides rapid and accurate changes to the water flow direction without any precise control device. However, a cavitation effect occurs because of the complicated bottom plug shape of the valve. In this study, the cavitation index and percent of cavitation (POC) were introduced to numerically evaluate fluid flows via computational fluid dynamics (CFD) analysis. To reduce the cavitation effect generated by the bottom plug, the optimal shape design was carried out through a parametric study, in which a simple computer-aided engineering (CAE) model was applied to avoid time-consuming CFD analysis and difficulties in achieving convergence. The optimal shape design process using full factorial design of experiments (DOEs) and an artificial neural network meta-model yielded the optimal waist and tail length of the bottom plug with a POC value of less than 30%, which meets the requirement of no cavitation occurrence. The optimal waist length, tail length and POC value were found to 6.42 mm, 6.96 mm and 27%, respectively.

  13. Optimal Control of Production and Remanufacturing in a Reverse Logistics Model with Backlogging

    Directory of Open Access Journals (Sweden)

    I. Konstantaras

    2010-01-01

    Full Text Available Reverse logistics activities have received increasing attention within logistics and operations management during the last years, both from a theoretical and a practical point of view. The field of reverse logistics includes all logistics processes starting with the take-back of used products from customers up to the stage of making them reusable products or disposing them. In this paper, a single-product recovery system is studied. In such system, used products are collected from customers and are kept at the recoverable inventory warehouse in view to be recovered. The constant demand rate can be satisfied either by newly produced products or by recovered ones (serviceable inventory, which are regarded as perfectly as the new ones. Excess demand is completely backlogged. Following an exact analytical approach, the optimal set-up numbers and the optimal lot sizes for the production of new products and for the recovery of returned products are obtained. A numerical cost comparison of this model with the corresponding one without backordering is also performed.

  14. Superhydrophilic-Superhydrophobic Patterned Surfaces as High-Density Cell Microarrays: Optimization of Reverse Transfection.

    Science.gov (United States)

    Ueda, Erica; Feng, Wenqian; Levkin, Pavel A

    2016-10-01

    High-density microarrays can screen thousands of genetic and chemical probes at once in a miniaturized and parallelized manner, and thus are a cost-effective alternative to microwell plates. Here, high-density cell microarrays are fabricated by creating superhydrophilic-superhydrophobic micropatterns in thin, nanoporous polymer substrates such that the superhydrophobic barriers confine both aqueous solutions and adherent cells within each superhydrophilic microspot. The superhydrophobic barriers confine and prevent the mixing of larger droplet volumes, and also control the spreading of droplets independent of the volume, minimizing the variability that arises due to different liquid and surface properties. Using a novel liposomal transfection reagent, ScreenFect A, the method of reverse cell transfection is optimized on the patterned substrates and several factors that affect transfection efficiency and cytotoxicity are identified. Higher levels of transfection are achieved on HOOC- versus NH2 -functionalized superhydrophilic spots, as well as when gelatin and fibronectin are added to the transfection mixture, while minimizing the amount of transfection reagent improves cell viability. Almost no diffusion of the printed transfection mixtures to the neighboring microspots is detected. Thus, superhydrophilic-superhydrophobic patterned surfaces can be used as cell microarrays and for optimizing reverse cell transfection conditions before performing further cell screenings. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Impact of furnishing on room airflow

    DEFF Research Database (Denmark)

    Lone Hedegaard, Mortensen; Rode, Carsten; Peuhkuri, Ruut

    2008-01-01

    temperatures in the winter season may lead to condensation or high relative humidity on the internal side of the building envelope. Therefore it was important to investigate the influence of furniture on the airflow patterns in rooms and on the local airflow behind the furniture. The current paper presents...

  16. Airflow Pattern Genereated by Three Air Diffusers

    DEFF Research Database (Denmark)

    Olmedo, Inés; Nielsen, Peter V.; de Adana, Manuel Ruiz

    The correct description of air diffusers plays a crucial role in the CFD predictions of the airflow pattern into a room. The numerical simulation of air distribution in an indoor space is challenging because of the complicated airflow pattern generated. An experimental study has been carried out ...

  17. Airflow Pattern Generated by Three Air Diffusers

    DEFF Research Database (Denmark)

    Olmedo, Inés; Nielsen, Peter V.; Ruiz de Adana, Manuel

    2011-01-01

    The correct description of air diffusers plays a crucial role in the CFD predictions of the airflow pattern into a room. The numerical simulation of air distribution in an indoor space is challenging because of the complicated airflow pattern generated. Many authors have developed simplified geom...

  18. Room Airflows with Low Reynolds Number Effects

    DEFF Research Database (Denmark)

    Topp, Claus; Nielsen, Peter V.; Davidson, Lars

    The behaviour of room airflows under fully turbulent conditions is well known both in terms of experiments and, numerical calculations by computational fluid dynamics (CFD). For room airflows where turbulence is not fully developed though, i.e. flows at low Reynolds numbers, the existing knowledge...

  19. Airflow Obstruction in Young Adults in Canada

    Directory of Open Access Journals (Sweden)

    Manal Al-Hazmi

    2007-01-01

    Full Text Available OBJECTIVE: Airflow obstruction is relatively uncommon in young adults, and may indicate potential for the development of progressive disease. The objective of the present study was to enumerate and characterize airflow obstruction in a random sample of Canadians aged 20 to 44 years.

  20. Airflow Pattern Generated by Three Air Diffusers

    DEFF Research Database (Denmark)

    Olmedo, Inés; Nielsen, Peter V.; Ruiz de Adana, Manuel

    2011-01-01

    The correct description of air diffusers plays a crucial role in the CFD predictions of the airflow pattern into a room. The numerical simulation of air distribution in an indoor space is challenging because of the complicated airflow pattern generated. Many authors have developed simplified geom...

  1. Multi-Response Optimization of Process Parameters for Imidacloprid Removal by Reverse Osmosis Using Taguchi Design.

    Science.gov (United States)

    Genç, Nevim; Doğan, Esra Can; Narcı, Ali Oğuzhan; Bican, Emine

    2017-05-01

      In this study, a multi-response optimization method using Taguchi's robust design approach is proposed for imidacloprid removal by reverse osmosis. Tests were conducted with different membrane type (BW30, LFC-3, CPA-3), transmembrane pressure (TMP = 20, 25, 30 bar), volume reduction factor (VRF = 2, 3, 4), and pH (3, 7, 11). Quality and quantity of permeate are optimized with the multi-response characteristics of the total dissolved solid (TDS), conductivity, imidacloprid, and total organic carbon (TOC) rejection ratios and flux of permeate. The optimized conditions were determined as membrane type of BW30, TMP 30 bar, VRF 3, and pH 11. Under these conditions, TDS, conductivity, imidacloprid, and TOC rejections and permeate flux were 97.50 97.41, 97.80, 98.00% and 30.60 L/m2·h, respectively. Membrane type was obtained as the most effective factor; its contribution is 64%. The difference between the predicted and observed value of multi-response signal/noise (MRSN) is within the confidence interval.

  2. Optimization of the Sequence of Washing Reverse Osmosis Membranes Used for Seawater Desalination

    Directory of Open Access Journals (Sweden)

    S. Gutierrez-Ruiz

    2017-04-01

    Full Text Available Seawater contains a number of organic and inorganic components that cause fouling of membranes when subjected to a process of reverse osmosis desalination. This fouling is one of the most important problems in the management of desalination plants, as it entails a significant loss in system performance. For membranes to be able to continue operating under appropriate conditions, they must undergo periodic cleaning protocols. This paper presents the results obtained when, subjecting a previously fouled aromatic polyamide membrane to different washing agents and using different concentrations of the same. Optimal concentrations of cleaning reagents were established. The results indicate that the performance of cleaning using a mixture of reagents, and alternating alkaline and acidic media, enabled maximum recovery of the membrane permeate flux (94.2 % and a significant reduction in the consumption of cleaning reagents.

  3. An optimal campaign structure for multicomponent batch distillation with reversible reaction

    Energy Technology Data Exchange (ETDEWEB)

    Wajge, R.M.; Reklaitis, G.V. [Purdue Univ., West Lafayette, IN (United States). School of Chemical Engineering

    1998-05-01

    When resource utilization and/or minimization of waste is comparable in importance to the production rate, the design of the operation policy should encompass an entire campaign of batches rather than a single batch. This notion of campaign optimization is particularly relevant to batch distillation with reversible reaction which produces significant amounts of off-cuts. Reprocessing these off-cuts merely based on consideration of a single batch may lead not only to inefficient production rates but also to the inefficient utilization of reactants. A general strategy for deciding the campaign structure for such an operation is presented. The concept of distillation characteristic is introduced, and its exploitation is shown to result in a simple but effective reprocessing policy for off-cuts. The economic benefits of such a campaign structure are demonstrated with the help of a case study.

  4. Structure-guided residence time optimization of a dabigatran reversal agent.

    Science.gov (United States)

    Schiele, Felix; van Ryn, Joanne; Litzenburger, Tobias; Ritter, Michael; Seeliger, Daniel; Nar, Herbert

    2015-01-01

    Novel oral anticoagulants are effective and safe alternatives to vitamin-K antagonists for anticoagulation therapy. However, anticoagulation therapy in general is associated with an elevated risk of bleeding. Idarucizumab is a reversal agent for the direct thrombin inhibitor, dabigatran etexilate (Pradaxa®) and is currently in Phase 3 studies. Here, we report data on the antibody fragment aDabi-Fab2, a putative backup molecule for idarucizumab. Although aDabi-Fab2 completely reversed effects of dabigatran in a rat model in vivo, we observed significantly reduced duration of action compared to idarucizumab. Rational protein engineering, based on the X-ray structure of aDabi-Fab2, led to the identification of mutant Y103W. The mutant had optimized shape complementarity to dabigatran while maintaining an energetically favored hydrogen bond. It displayed increased affinity for dabigatran, mainly driven by a slower off-rate. Interestingly, the increased residence time translated into longer duration of action in vivo. It was thus possible to further enhance the efficacy of aDabi-Fab2 based on rational design, giving it the potential to serve as a back-up candidate for idarucizumab.

  5. Determination of gallic acid with rhodanine by reverse flow injection analysis using simplex optimization.

    Science.gov (United States)

    Phakthong, Wilaiwan; Liawruangrath, Boonsom; Liawruangrath, Saisunee

    2014-12-01

    A reversed flow injection (rFI) system was designed and constructed for gallic acid determination. Gallic acid was determined based on the formation of chromogen between gallic acid and rhodanine, resulting in a colored product with a λmax at 520 nm. The optimum conditions for determining gallic acid were also investigated. Optimizations of the experimental conditions were carried out based on the so-call univariate method. The conditions obtained were 0.6% (w/v) rhodanine, 70% (v/v) ethanol, 0.9 mol L(-1) NaOH, 2.0 mL min(-1) flow rate, 75 μL injection loop and 600 cm mixing tubing length, respectively. Comparative optimizations of the experimental conditions were also carried out by multivariate or simplex optimization method. The conditions obtained were 1.2% (w/v) rhodanine, 70% (v/v) ethanol, 1.2 mol L(-1) NaOH, flow rate 2.5 mL min(-1), 75 μL injection loop and 600 cm mixing tubing length, respectively. It was found that the optimum conditions obtained by the former optimization method were mostly similar to those obtained by the latter method. The linear relationship between peak height and the concentration of gallic acid was obtained over the range of 0.1-35.0 mg L(-1) with the detection limit 0.081 mg L(-1). The relative standard deviations were found to be in the ranges 0.46-1.96% for 1, 10, 30 mg L(-1) of gallic acid (n=11). The method has the advantages of simplicity extremely high selectivity and high precision. The proposed method was successfully applied to the determination of gallic acid in longan samples without interferent effects from other common phenolic compounds that might be present in the longan samples collected in northern Thailand.

  6. A "Reverse-Schur" Approach to Optimization With Linear PDE Constraints: Application to Biomolecule Analysis and Design.

    Science.gov (United States)

    Bardhan, Jaydeep P; Altman, Michael D; Tidor, B; White, Jacob K

    2009-01-01

    We present a partial-differential-equation (PDE)-constrained approach for optimizing a molecule's electrostatic interactions with a target molecule. The approach, which we call reverse-Schur co-optimization, can be more than two orders of magnitude faster than the traditional approach to electrostatic optimization. The efficiency of the co-optimization approach may enhance the value of electrostatic optimization for ligand-design efforts-in such projects, it is often desirable to screen many candidate ligands for their viability, and the optimization of electrostatic interactions can improve ligand binding affinity and specificity. The theoretical basis for electrostatic optimization derives from linear-response theory, most commonly continuum models, and simple assumptions about molecular binding processes. Although the theory has been used successfully to study a wide variety of molecular binding events, its implications have not yet been fully explored, in part due to the computational expense associated with the optimization. The co-optimization algorithm achieves improved performance by solving the optimization and electrostatic simulation problems simultaneously, and is applicable to both unconstrained and constrained optimization problems. Reverse-Schur co-optimization resembles other well-known techniques for solving optimization problems with PDE constraints. Model problems as well as realistic examples validate the reverse-Schur method, and demonstrate that our technique and alternative PDE-constrained methods scale very favorably compared to the standard approach. Regularization, which ordinarily requires an explicit representation of the objective function, can be included using an approximate Hessian calculated using the new BIBEE/P (boundary-integral-based electrostatics estimation by preconditioning) method.

  7. Route towards the optimization at given power of thermoelectric heat engines with broken time-reversal symmetry

    Science.gov (United States)

    Zhang, Rong; Li, Qian-Wen; Tang, F. R.; Yang, X. Q.; Bai, L.

    2017-08-01

    We investigate the performance at a given power of a thermoelectric heat engine with broken time-reversal symmetry, and derive analytically the efficiency at a given power of a thermoelectric generator within linear irreversible thermodynamics. A universal bound on the efficiency of the thermoelectric heat engine is achieved under a strong constraint on the Onsager coefficients, and some interesting features are further revealed. Our results demonstrate that there exists a trade-off between efficiency and power output, and the efficiency at a given power may surpass the Curzon-Ahlborn limit due to broken time-reversal symmetry. Moreover, optimal efficiency at a given power can be achieved, which indicates that broken time-reversal symmetry offers physically allowed ways to optimize the performance of heat engines. Our study may contribute to the interesting guidelines for optimizing actual engines.

  8. Second-law analysis and optimization of reverse brayton cycles of different configurations for cryogenic applications

    Science.gov (United States)

    Streit, James Ryder; Razani, Arsalan

    2012-06-01

    Second-law of thermodynamics (2nd law) and exergy analyses and optimization offour Reverse Brayton Refrigeration (RBR) cryogenic cycle configurations: Conventional 1-stage compression cycle; Conventional 2-stage compression cycle; 1-stage compressionModified cycle with intermediate cooling of the recuperator using an auxiliary cooler; andan Integrated 2-stage expansion RBR cycle are performed. The conventional RBR cyclesare analyzed for low and high pressure ratio applications using multistage compressorswith intercooling. Analytical solutions for the conventional cycles are developed includingthermal and fluid flow irreversibilities of the recuperators and all heat exchangers inaddition to the compression and expansion processes. Analytical solutions are used to findthe thermodynamic bounds for the performance of the cycles. Exergy irreversibilitydiagrams of the cycles are developed and the effects of important system parameters onRBR cycle performance are investigated. 2nd law/exergy analyses, and optimization of thecycles with intermediate cooling of the recuperator, considering the cooling temperatureand the recuperator effectiveness and pressure drop, are included. The effect of the 2ndlaw/exergy efficiency of the auxiliary cooler on the total system efficiencies is presented.

  9. Optimization of a commercial, medium size, reversible heat pump for use with propane

    Energy Technology Data Exchange (ETDEWEB)

    Corberan, J.M. [Dept. of Applied Thermodynamics, Univ. Politecnica de Valencia (Spain); Urchueguia, J.F. [Dept. of Applied Physics, Univ. Politecnica de Valencia (Spain); Conde, M. [Manuel Conde Eng., Zuerich (Switzerland); Setaro, T. [Ente per le Nuove Tecnologie, l' Energia e l' Ambiente (ENEA), Energy Dept., S.M. di Galeria (Italy); Sartori, L.; Zorzin, A. [Alfa Laval-Artec Spa, Alonte (Italy); Granryd, E.; Palm, B. [Kungl Tekniska Hokskolan, Stockholm (Sweden); Saez, J.; Ramos, A. [Cia. Industrial de Aplicaciones Tecnicas S.A., Cordoba (Spain); Blas, J. de [Asociacion Espanola para la Diagnosis y la Investigacion en Energia (AEDIE), Madrid (Spain)

    1999-07-01

    In this paper we give a summarized description of the HEAHP/J3 project, currently running under the support of the European Commission. In the frame of this project, a medium size reversible air to water heat pump for use with propane (R290) and appropriate for south European countries - in which refrigeration is a strong demand - is currently being developed by the partners. The starting point is a 20 kW, R22, commercial heat pump from CIATESA, a major Spanish heat pump manufacturer, which will be adapted and optimized for the use of propane as refrigerant. Computer simulations are under development aiming to identify the improvements and/or modifications needed in the components to ensure safe use and high efficiency, in terms of COP, of the heat pump. The scope of these models is to assist the optimization and design of the different elements of the heat pump. To aid the adjustment of these models while generating a large database covering the behavior of propane as a refrigerant, individualized characterization experiments of all pump components will be performed. Both aspects, modeling and measurements, are issued to converge in the reduction of size of all components resulting from the use of efficient extended surfaces in the heat exchangers and (for a given refrigeration or heat capacity) in the improvement of overall efficiency through the appropriate selection or adaptation, as far as possible, of the compressor. (orig.)

  10. Evolving neural network optimization of cholesteryl ester separation by reversed-phase HPLC.

    Science.gov (United States)

    Jansen, Michael A; Kiwata, Jacqueline; Arceo, Jennifer; Faull, Kym F; Hanrahan, Grady; Porter, Edith

    2010-07-01

    Cholesteryl esters have antimicrobial activity and likely contribute to the innate immunity system. Improved separation techniques are needed to characterize these compounds. In this study, optimization of the reversed-phase high-performance liquid chromatography separation of six analyte standards (four cholesteryl esters plus cholesterol and tri-palmitin) was accomplished by modeling with an artificial neural network-genetic algorithm (ANN-GA) approach. A fractional factorial design was employed to examine the significance of four experimental factors: organic component in the mobile phase (ethanol and methanol), column temperature, and flow rate. Three separation parameters were then merged into geometric means using Derringer's desirability function and used as input sources for model training and testing. The use of genetic operators proved valuable for the determination of an effective neural network structure. Implementation of the optimized method resulted in complete separation of all six analytes, including the resolution of two previously co-eluting peaks. Model validation was performed with experimental responses in good agreement with model-predicted responses. Improved separation was also realized in a complex biological fluid, human milk. Thus, the first known use of ANN-GA modeling for improving the chromatographic separation of cholesteryl esters in biological fluids is presented and will likely prove valuable for future investigators involved in studying complex biological samples.

  11. Airflow obstruction in young adults in Canada

    DEFF Research Database (Denmark)

    Al-Hazmi, Manal; Wooldrage, Kate; Anthonisen, Nicholas R.;

    2007-01-01

    OBJECTIVE: Airflow obstruction is relatively uncommon in young adults, and may indicate potential for the development of progressive disease. The objective of the present study was to enumerate and characterize airflow obstruction in a random sample of Canadians aged 20 to 44 years. SETTING......% were nonsmokers with asthma and 17% were nonsmokers with no history of asthma. Bronchial hyper-responsiveness increased the prevalence of airflow obstruction in each of these groups. CONCLUSION: Smoking and asthma, jointly and individually, are major determinants of obstructive disorders in young...... adults. Bronchial hyper-responsiveness contributes to obstruction in both groups....

  12. Automation of reverse engineering process in aircraft modeling and related optimization problems

    Science.gov (United States)

    Li, W.; Swetits, J.

    1994-01-01

    During the year of 1994, the engineering problems in aircraft modeling were studied. The initial concern was to obtain a surface model with desirable geometric characteristics. Much of the effort during the first half of the year was to find an efficient way of solving a computationally difficult optimization model. Since the smoothing technique in the proposal 'Surface Modeling and Optimization Studies of Aerodynamic Configurations' requires solutions of a sequence of large-scale quadratic programming problems, it is important to design algorithms that can solve each quadratic program in a few interactions. This research led to three papers by Dr. W. Li, which were submitted to SIAM Journal on Optimization and Mathematical Programming. Two of these papers have been accepted for publication. Even though significant progress has been made during this phase of research and computation times was reduced from 30 min. to 2 min. for a sample problem, it was not good enough for on-line processing of digitized data points. After discussion with Dr. Robert E. Smith Jr., it was decided not to enforce shape constraints in order in order to simplify the model. As a consequence, P. Dierckx's nonparametric spline fitting approach was adopted, where one has only one control parameter for the fitting process - the error tolerance. At the same time the surface modeling software developed by Imageware was tested. Research indicated a substantially improved fitting of digitalized data points can be achieved if a proper parameterization of the spline surface is chosen. A winning strategy is to incorporate Dierckx's surface fitting with a natural parameterization for aircraft parts. The report consists of 4 chapters. Chapter 1 provides an overview of reverse engineering related to aircraft modeling and some preliminary findings of the effort in the second half of the year. Chapters 2-4 are the research results by Dr. W. Li on penalty functions and conjugate gradient methods for

  13. Numerical study of airflow over breaking waves

    Science.gov (United States)

    Yang, Zixuan; Shen, Lian

    2016-11-01

    We present direct numerical simulation (DNS) results on airflow over breaking waves. Air and water are simulated as a coherent system. The initial condition for the simulation is a fully-developed turbulent airflow over strongly-forced steep waves. The airflow is driven by a shear stress at the top. The effects of the initial wave steepness and wave age are studied systematically. Because wave breaking is an unsteady process, we use ensemble averaging of a large number of runs to obtain turbulent statistics. Simulation results show that the airflow above does not see the wave trough during wave breaking. Vortex structures at different stages of wave breaking are analyzed based on a linear stochastic estimation method. It is found that the wave breaking alters the pattern of vortex structures.

  14. Occupational Exposures and Chronic Airflow Limitation

    Directory of Open Access Journals (Sweden)

    Helen Dimich-Ward

    1996-01-01

    Full Text Available The recent literature was reviewed to evaluate whether chronic airflow limitation is associated with occupational exposures to dusts. Only those studies that controlled for the effects of smoking were included. There is compelling evidence that exposure to inorganic dusts, such as from coal and hardrock mining or asbestos, are associated with the development of chronic airflow limitation, independently of pneumoconiosis. Nonsmoking gold miners are particularly at high risk of airflow obstruction and emphysema. Findings from studies of organic dusts, such as exposures to wood, cotton, grain or other agricultural dusts, or to mixed dust exposures, were less consistent but tended to show positive dose-response associations. In the majority of studies, no statistical interaction was shown between dust exposures and smoking; however, the effects of the dust exposures were often more pronounced. An occupational history should be considered, in addition to a smoking history, as an integral part of an investigation of chronic airflow limitation in a patient.

  15. Reverse Logistics

    OpenAIRE

    Kulikova, Olga

    2016-01-01

    This thesis was focused on the analysis of the concept of reverse logistics and actual reverse processes which are implemented in mining industry and finding solutions for the optimization of reverse logistics in this sphere. The objective of this paper was the assessment of the development of reverse logistics in mining industry on the example of potash production. The theoretical part was based on reverse logistics and mining waste related literature and provided foundations for further...

  16. Building of Reusable Reverse Logistics Model and its Optimization Considering the Decision of Backorder or Next Arrival of Goods

    Science.gov (United States)

    Lee, Jeong-Eun; Gen, Mitsuo; Rhee, Kyong-Gu; Lee, Hee-Hyol

    This paper deals with the building of the reusable reverse logistics model considering the decision of the backorder or the next arrival of goods. The optimization method to minimize the transportation cost and to minimize the volume of the backorder or the next arrival of goods occurred by the Just in Time delivery of the final delivery stage between the manufacturer and the processing center is proposed. Through the optimization algorithms using the priority-based genetic algorithm and the hybrid genetic algorithm, the sub-optimal delivery routes are determined. Based on the case study of a distilling and sale company in Busan in Korea, the new model of the reusable reverse logistics of empty bottles is built and the effectiveness of the proposed method is verified.

  17. Airflow resistance of airflow-regulating devices described by independent coefficients

    NARCIS (Netherlands)

    Verkerke, GJ; Geertsema, AA; Schutte, HK

    2001-01-01

    Rehabilitation after laryngectomy includes more and more the use of airflow-regulating devices such as shunt valves (SVs). tracheostoma valves (TSVs), and heat and moisture exchange (HME) filters. In determining the quality of those devices, airflow resistance is a very important factor. It is curre

  18. Measurement of airflow in residential furnaces

    Energy Technology Data Exchange (ETDEWEB)

    Biermayer, Peter J.; Lutz, James; Lekov, Alex

    2004-01-24

    In order to have a standard for furnaces that includes electricity consumption or for the efficiency of furnace blowers to be determined, it is necessary to determine the airflow of a furnace or furnace blower. This study focused on airflow testing, in order to determine if an existing test method for measuring blower airflow could be used to measure the airflow of a furnace, under conditions seen in actual installations and to collect data and insights into the operating characteristics of various types of furnace blowers, to use in the analysis of the electricity consumption of furnaces. Results of the measured airflow on furnaces with three types of blower and motor combinations are presented in the report. These included: (1) a forward-curved blower wheel with a typical permanent split capacitor (PSC) motor, (2) a forward-curved blower wheel with an electronically-commutated motor (ECM), and (3) a prototype blower, consisting of a backward-inclined blower wheel matched to an ECM motor prototype, which is being developed as an energy-saving alternative to conventional furnace blowers. The testing provided data on power consumption, static and total pressure, and blower speed.

  19. Designing cost-effective seawater reverse osmosis system under optimal energy options

    Energy Technology Data Exchange (ETDEWEB)

    Gilau, Asmerom M.; Small, Mitchell J. [Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, PA 15213 (United States)

    2008-04-15

    Today, three billion people around the world have no access to clean drinking water and about 1.76 billion people live in areas already facing a high degree of water stress. This paper analyzes the cost-effectiveness of a stand alone small-scale renewable energy-powered seawater reverse osmosis (SWRO) system for developing countries. In this paper, we have introduced a new methodology; an energy optimization model which simulates hourly power production from renewable energy sources. Applying the model using the wind and solar radiation conditions for Eritrea, East Africa, we have computed hourly water production for a two-stage SWRO system with a capacity of 35 m{sup 3}/day. According to our results, specific energy consumption is about 2.33 kW h/m{sup 3}, which is a lower value than that achieved in most of the previous designs. The use of a booster pump, energy recovery turbine and an appropriate membrane, allows the specific energy consumption to be decreased by about 70% compared to less efficient design without these features. The energy recovery turbine results in a reduction in the water cost of about 41%. Our results show that a wind-powered system is the least cost and a PV-powered system the most expensive, with finished water costs of about 0.50 and 1.00/m{sup 3}, respectively. By international standards, for example, in China, these values are considered economically feasible. Detailed simulations of the RO system design, energy options, and power, water, and life-cycle costs are presented. (author)

  20. Finite Element Modeling of Airflow During Phonation

    Directory of Open Access Journals (Sweden)

    Šidlof P.

    2010-07-01

    Full Text Available In the paper a mathematical model of airflow in human vocal folds is presented. The geometry of the glottal channel is based on measurements of excised human larynges. The airflow is modeled by nonstationary incompressible Navier-Stokes equations in a 2D computational domain, which is deformed in time due to vocal fold vibration. The paper presents numerical results and focuses on flow separation in glottis. Quantitative data from numerical simulations are compared to results of measurements by Particle Image Velocimetry (PIV, performed on a scaled self-oscillating physical model of vocal folds.

  1. DESIGN OF OPTIMAL CARRY SKIP ADDER AND CARRY SKIP BCD ADDER USING REVERSIBLE LOGIC GATES

    OpenAIRE

    Praveena Murugesan; Thanushkodi Keppanagounder

    2014-01-01

    Reversible logic circuits have the ability to produce zero power dissipation which has found its importance in quantum computing, optical computing and low power digital circuits. The study presents improved and efficient reversible logic circuits for carry skip adder and carry skip BCD adder. The performance of the proposed architecture is better than the existing works in terms of gate count, garbage outputs and constant inputs. This design forms the basis for different quantum ALU and embe...

  2. Airflow Test of Acoustic Board Samples

    DEFF Research Database (Denmark)

    Jensen, Rasmus Lund; Jensen, Lise Mellergaard

    In the laboratory of Indoor Environmental Engineering, Department of Civil Engineering, Aalborg University an airflow test on 2x10 samples of acoustic board were carried out the 2nd of June 2012. The tests were carried out for Rambøll and STO AG. The test includes connected values of volume flow...

  3. Structure of the airflow above surface waves

    Science.gov (United States)

    Buckley, Marc; Veron, Fabrice

    2016-04-01

    Weather, climate and upper ocean patterns are controlled by the exchanges of momentum, heat, mass, and energy across the ocean surface. These fluxes are, in turn, influenced by the small-scale physics at the wavy air-sea interface. We present laboratory measurements of the fine-scale airflow structure above waves, achieved in over 15 different wind-wave conditions, with wave ages Cp/u* ranging from 1.4 to 66.7 (where Cp is the peak phase speed of the waves, and u* the air friction velocity). The experiments were performed in the large (42-m long) wind-wave-current tank at University of Delaware's Air-Sea Interaction laboratory (USA). A combined Particle Image Velocimetry and Laser Induced Fluorescence system was specifically developed for this study, and provided two-dimensional airflow velocity measurement as low as 100 um above the air-water interface. Starting at very low wind speeds (U10~2m/s), we directly observe coherent turbulent structures within the buffer and logarithmic layers of the airflow above the air-water interface, whereby low horizontal velocity air is ejected away from the surface, and higher velocity fluid is swept downward. Wave phase coherent quadrant analysis shows that such turbulent momentum flux events are wave-phase dependent. Airflow separation events are directly observed over young wind waves (Cp/u*wind waves (Cp/u*=3.7). Over slightly older wind waves (Cp/u* = 6.5), the measured wave-induced airflow perturbations are qualitatively consistent with linear critical layer theory.

  4. Cost-benefit study of consumer product take-back programs using IBM's WIT reverse logistics optimization tool

    Science.gov (United States)

    Veerakamolmal, Pitipong; Lee, Yung-Joon; Fasano, J. P.; Hale, Rhea; Jacques, Mary

    2002-02-01

    In recent years, there has been increased focus by regulators, manufacturers, and consumers on the issue of product end of life management for electronics. This paper presents an overview of a conceptual study designed to examine the costs and benefits of several different Product Take Back (PTB) scenarios for used electronics equipment. The study utilized a reverse logistics supply chain model to examine the effects of several different factors in PTB programs. The model was done using the IBM supply chain optimization tool known as WIT (Watson Implosion Technology). Using the WIT tool, we were able to determine a theoretical optimal cost scenario for PTB programs. The study was designed to assist IBM internally in determining theoretical optimal Product Take Back program models and determining potential incentives for increasing participation rates.

  5. Designing a Multistage Supply Chain in Cross-Stage Reverse Logistics Environments: Application of Particle Swarm Optimization Algorithms

    Directory of Open Access Journals (Sweden)

    Tzu-An Chiang

    2014-01-01

    Full Text Available This study designed a cross-stage reverse logistics course for defective products so that damaged products generated in downstream partners can be directly returned to upstream partners throughout the stages of a supply chain for rework and maintenance. To solve this reverse supply chain design problem, an optimal cross-stage reverse logistics mathematical model was developed. In addition, we developed a genetic algorithm (GA and three particle swarm optimization (PSO algorithms: the inertia weight method (PSOA_IWM, VMax method (PSOA_VMM, and constriction factor method (PSOA_CFM, which we employed to find solutions to support this mathematical model. Finally, a real case and five simulative cases with different scopes were used to compare the execution times, convergence times, and objective function values of the four algorithms used to validate the model proposed in this study. Regarding system execution time, the GA consumed more time than the other three PSOs did. Regarding objective function value, the GA, PSOA_IWM, and PSOA_CFM could obtain a lower convergence value than PSOA_VMM could. Finally, PSOA_IWM demonstrated a faster convergence speed than PSOA_VMM, PSOA_CFM, and the GA did.

  6. Designing a multistage supply chain in cross-stage reverse logistics environments: application of particle swarm optimization algorithms.

    Science.gov (United States)

    Chiang, Tzu-An; Che, Z H; Cui, Zhihua

    2014-01-01

    This study designed a cross-stage reverse logistics course for defective products so that damaged products generated in downstream partners can be directly returned to upstream partners throughout the stages of a supply chain for rework and maintenance. To solve this reverse supply chain design problem, an optimal cross-stage reverse logistics mathematical model was developed. In addition, we developed a genetic algorithm (GA) and three particle swarm optimization (PSO) algorithms: the inertia weight method (PSOA_IWM), V(Max) method (PSOA_VMM), and constriction factor method (PSOA_CFM), which we employed to find solutions to support this mathematical model. Finally, a real case and five simulative cases with different scopes were used to compare the execution times, convergence times, and objective function values of the four algorithms used to validate the model proposed in this study. Regarding system execution time, the GA consumed more time than the other three PSOs did. Regarding objective function value, the GA, PSOA_IWM, and PSOA_CFM could obtain a lower convergence value than PSOA_VMM could. Finally, PSOA_IWM demonstrated a faster convergence speed than PSOA_VMM, PSOA_CFM, and the GA did.

  7. Sugammadex to reverse neuromuscular blockade and provide optimal conditions for motor-evoked potential monitoring

    Directory of Open Access Journals (Sweden)

    Mehdi Trifa

    2017-01-01

    Full Text Available Sugammadex is a novel pharmacologic agent, which reverses neuromuscular blockade (NMB via a mechanism that differs completely from acetylcholinesterase inhibitors. By encapsulating rocuronium, sugammadex can provide recovery of neuromuscular function even when there is a profound degree of NMB. We report anecdotal experience with the use of sugammadex to reverse NMB to facilitate intraoperative neurophysiological monitoring (motor evoked potentials in an adolescent with scoliosis during posterior spinal fusion. Its potential application in this unique clinical scenario is discussed, and potential dosing schemes are reviewed.

  8. On Reverse Stackelberg Game and Optimal Mean Field Control for a Large Population of Thermostatically Controlled Loads

    Energy Technology Data Exchange (ETDEWEB)

    Li, Sen; Zhang, Wei; Lian, Jianming; Kalsi, Karanjit

    2016-07-08

    This paper studies a multi-stage pricing problem for a large population of thermostatically controlled loads. The problem is formulated as a reverse Stackelberg game that involves a mean field game in the hierarchy of decision making. In particular, in the higher level, a coordinator needs to design a pricing function to motivate individual agents to maximize the social welfare. In the lower level, the individual utility maximization problem of each agent forms a mean field game coupled through the pricing function that depends on the average of the population control/state. We derive the solution to the reverse Stackelberg game by connecting it to a team problem and the competitive equilibrium, and we show that this solution corresponds to the optimal mean field control that maximizes the social welfare. Realistic simulations are presented to validate the proposed methods.

  9. An optimization model for sustainable solutions towards implementation of reverse logistics under collaborative framework

    DEFF Research Database (Denmark)

    Agarwal, Vernika; Govindan, Kannan; Darbari, Jyoti Dhingra

    2016-01-01

    Enforced Legislations, social image, corporate citizenship and market competence are forcing manufacturing enterprises (MEs) to incorporate reverse logistics (RL) into their supply chains. RL can be used as a strategic tool to gain customer loyalty and reduce operational costs by maximizing...

  10. Delay Optimization of Low Power Reversible Gate using MOS Transistor Level design

    Directory of Open Access Journals (Sweden)

    Mukesh Kumar Kushwaha

    2015-10-01

    Full Text Available In Semiconductor industry has witnessed and explosive growth of integration of sophisticated multimedia base application onto mobile electronic gadget since the last decade. The critical concern in this aspect is to reduce the power consumption beyond a certain range of operating frequency. An important factor in the design of VLSI circuits is the choices of reversible logic. Basically conventionally digital circuits have been implemented using the logic gates, which were irreversible in nature only NOT gate are reversible. These irreversible gates produce energy loss due to the information bits lost during the operation information loss occurs because the total number of output signals generated is less than total number of input signals applied. In reversible if the input vector can be uniquely recovered from the output vector and if there is a one to one correspondence between its input and output logic. This paper present a new representation of existing reversible gate in MOS transistor. The MOS transistor designing using a gate diffusion input. Those new representation of MOS transistor has a hoping future in design of low power consumption circuits and high speed application

  11. Open-source CFD model for optimization of forward osmosis and reverse osmosis membrane modules

    DEFF Research Database (Denmark)

    Gruber, Mathias Felix; Aslak, Ulf; Hélix-Nielsen, Claus

    2016-01-01

    Osmotic membrane separation processes are based on using semi-permeable membranes to remove solutes from a given feed solution. This can happen either as Reverse Osmosis (RO) where a hydraulic pressure is applied to drive separation across the membrane, or as Forward Osmosis (FO) where osmotic pr...

  12. Simulation of Thermal Distribution and Airflow for Efficient Energy Consumption in a Small Data Centers

    Directory of Open Access Journals (Sweden)

    Jing Ni

    2017-04-01

    Full Text Available Data centers have become ubiquitous in the last few years in an attempt to keep pace with the processing and storage needs of the Internet and cloud computing. The steady growth in the heat densities of IT servers leads to a rise in the energy needed to cool them, and constitutes approximately 40% of the power consumed by data centers. However, many data centers feature redundant air conditioning systems that contribute to inefficient air distribution, which significantly increases energy consumption. This remains an insufficiently explored problem. In this paper, a typical, small data center with tiles for an air supply system with a raised floor is used. We use a fluent (Computational Fluid Dynamics, CFD to simulate thermal distribution and airflow, and investigate the optimal conditions of air distribution to save energy. The effects of the airflow outlet angle along the tile, the cooling temperature and the rate of airflow on the beta index as well as the energy utilization index are discussed, and the optimal conditions are obtained. The reasonable airflow distribution achieved using 3D CFD calculations and the parameter settings provided in this paper can help reduce the energy consumption of data centers by improving the efficiency of the air conditioning.

  13. Estimation of Airflow in livestock Buildings

    DEFF Research Database (Denmark)

    Larsen, Rasmus

    1995-01-01

    sickness among the livestock. Therefore it is of interest to estimate flow vector fields corresponding to the airflow introduced by a given ventilation system. By introducing particles (e.g. smoke or soapbubles) into the air-inlets of a model of a livestock building, the airflow in an laser......-illuminated plane may be visualized. Based of sequences of images recorded of this plane local measurements of the velocity field are obtained by analysis of the local energy distribution, which is sampled using a set of 3-D spatio-temporal Gabor filters. We will show how physically inspired a priori distribution...... of the flow field may be used to integrate the local observations to a smooth field....

  14. Optimization of protein extraction process from jackfruit seed flour by reverse micelle system

    Directory of Open Access Journals (Sweden)

    Maycon Fagundes Teixeira Reis

    2016-06-01

    Full Text Available The extraction of protein from flour of jackfruit seeds by reverse micelles was evaluated. Reverse micelle system was composed of sodium dodecyl sulfate (SDS as surfactant, butanol as solvent, and water. The effects of stirring time, temperature, molar ratio H2O SDS-1, concentration of butanol (mass percentage and flour mass were tested in batch systems. Based on the adjusted linear regression model, only butanol concentration provided optimum extraction conditions (41.16%. Based on the analysis of surface response, the best extraction yield could be obtained at 25°C, stirring time of 120 min, mass of flour of 100 mg, and a ratio H2O SDS-1 of 50. Experimental results showed that a 79.00% extraction yield could be obtained.

  15. Optimizing selectivity during reversed-phase high performance liquid chromatography method development: prioritizing experimental conditions.

    Science.gov (United States)

    Snyder, Lloyd R; Dolan, John W

    2013-08-09

    Several different conditions can be varied to improve selectivity for reversed-phase chromatography (RPC). A reexamination of literature data suggests that changes in selectivity due to a change of column or mobile phase pH are largely replicated by changes in temperature or mobile phase composition (concentrations of acetonitrile and/or methanol). This suggests a reconsideration of the role of mobile phase pH and the column during method development.

  16. Cooling airflow design tool for displacement ventilation.

    OpenAIRE

    Schiavon, Stefano; Bauman, Fred

    2009-01-01

    These user notes describe how to use a spreadsheet-based (Excel 2007) version of the ASHRAE method (Chen and Glicksman 2003) for calculating the amount of design cooling airflow required for a displacement ventilation (DV) system that is providing all sensible cooling for a conditioned space. The design tool has been developed by CBE and is available on the CBE Partner website: http://www.cbe.berkeley.edu/partners/downloads.php

  17. Multi-objective Optimization of Controller for Process with Reverse Response and Dead Time

    Institute of Scientific and Technical Information of China (English)

    WANG Guo-liang; SHAO Hui-he

    2009-01-01

    Due to the difficulty of controlling the process with inverse response and dead time, a Multi-objective Optimization based on Genetic Algorithm (MOGA) method for tuning of proportional-integral-derivative (PID) controller is proposed. The settings of the controller are valued by two criteria, the error between output and reference signals and control moves. An appropriate set of Pareto optimal setting of the PID controller is founded by analyzing the results of Pareto optimal surfaces for balancing the two criteria. A high order process with inverse response and dead time is used to illustrate the results of the proposed method. And the efficiency and robustness of the tuning method are evident compared with methods in recent literature.

  18. On Variable Reverse Power Flow-Part I: Active-Reactive Optimal Power Flow with Reactive Power of Wind Stations

    Directory of Open Access Journals (Sweden)

    Aouss Gabash

    2016-02-01

    Full Text Available It has recently been shown that using battery storage systems (BSSs to provide reactive power provision in a medium-voltage (MV active distribution network (ADN with embedded wind stations (WSs can lead to a huge amount of reverse power to an upstream transmission network (TN. However, unity power factors (PFs of WSs were assumed in those studies to analyze the potential of BSSs. Therefore, in this paper (Part-I, we aim to further explore the pure reactive power potential of WSs (i.e., without BSSs by investigating the issue of variable reverse power flow under different limits on PFs in an electricity market model. The main contributions of this work are summarized as follows: (1 Introducing the reactive power capability of WSs in the optimization model of the active-reactive optimal power flow (A-R-OPF and highlighting the benefits/impacts under different limits on PFs. (2 Investigating the impacts of different agreements for variable reverse power flow on the operation of an ADN under different demand scenarios. (3 Derivation of the function of reactive energy losses in the grid with an equivalent-π circuit and comparing its value with active energy losses. (4 Balancing the energy curtailment of wind generation, active-reactive energy losses in the grid and active-reactive energy import-export by a meter-based method. In Part-II, the potential of the developed model is studied through analyzing an electricity market model and a 41-bus network with different locations of WSs.

  19. Modeling and fabrication of a planar thin film airflow sensor

    Science.gov (United States)

    Adamec, Richard J.; Tanner, Philip G.; Thiel, David V.

    2001-11-01

    A thin film airflow transducer based on the hot wire anemometer principle was designed using current MEMS modelling & simulation software. Flow sensors are commonly implemented with thermal isolation of the sensor from the bulk substrate mass using methods such as reverse side etching or sacrificial layers, however this paper will present a sensor relying on thermal insulation only. This insulation may be provided by layers of material exhibiting relatively poor thermal conduction characteristics such as silicon dioxide or polyimide, giving rise to a number of advantages such as removing the process of reverse side etching. Limiting fabrication to use of simple processes such as photolithography and sputtering/evaporative deposition also simplifies this design and assists in greatly increasing the compatibility with standard CMOS fabrication processes and materials. A combination of both theoretical computer modelling and physical fabrication and testing has been the approach to this research. Preliminary testing of this design has demonstrated small yet measurable temperature gradients across the device surface during steady state operation. The novel approach to this device is the investigation of pulsed operation, effectively a transient analysis that allows the thermal conduction effects of the bulk mass to be significantly reduced, leading to a significant increase of both efficiency and response time. Electro-thermo-mechanical and computational fluid dynamic analysis of the structure successfully model the thermal conduction, radiation and forced convection effects of the device during and after ohmic heating of the sensor's heating element.

  20. A Dynamic Optimization Strategy for the Operation of Large Scale Seawater Reverses Osmosis System

    Directory of Open Access Journals (Sweden)

    Aipeng Jiang

    2014-01-01

    Full Text Available In this work, an efficient strategy was proposed for efficient solution of the dynamic model of SWRO system. Since the dynamic model is formulated by a set of differential-algebraic equations, simultaneous strategies based on collocations on finite element were used to transform the DAOP into large scale nonlinear programming problem named Opt2. Then, simulation of RO process and storage tanks was carried element by element and step by step with fixed control variables. All the obtained values of these variables then were used as the initial value for the optimal solution of SWRO system. Finally, in order to accelerate the computing efficiency and at the same time to keep enough accuracy for the solution of Opt2, a simple but efficient finite element refinement rule was used to reduce the scale of Opt2. The proposed strategy was applied to a large scale SWRO system with 8 RO plants and 4 storage tanks as case study. Computing result shows that the proposed strategy is quite effective for optimal operation of the large scale SWRO system; the optimal problem can be successfully solved within decades of iterations and several minutes when load and other operating parameters fluctuate.

  1. Airflow Simulations around OA Intake Louver with Electronic Velocity Sensors

    OpenAIRE

    Han, Hwataik

    2011-01-01

    It is important to control outdoor airflow rates into HVAC systems in terms of energy conservation and healthy indoor environment. Technologies are being developed to measure outdoor air (OA) flow rates through OA intake louvers on a real time basis. The purpose of this paper is to investigate the airflow characteristics through an OA intake louver numerically in order to provide suggestions for sensor installations. Airflow patterns are simulated with and without electronic air velocity sens...

  2. Considerations for efficient airflow design in cleanrooms

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Tengfang

    2004-07-29

    A high-performance cleanroom should provide efficient energy performance in addition to effective contamination control. Energy-efficient designs can yield capital and operational cost savings, and can be part of a strategy to improve productivity in the cleanroom industry. Based upon in-situ measurement data from ISO Class 5 clean rooms, this article discusses key factors affecting cleanroom air system performance and benefits of efficient airflow design in clean rooms. Cleanroom HVAC systems used in the semiconductor, pharmaceutical, and healthcare industries are very energy intensive, requiring large volumes of cleaned air to remove or dilute contaminants for satisfactory operations. There is a tendency, however, to design excessive airflow rates into cleanroom HVAC systems, due to factors such as design conservatism, lack of thorough understanding of airflow requirements, concerns about cleanliness reliability, and potential design and operational liabilities. Energy use of cleanroom environmental systems varies with system type and design, cleanroom functions, and the control of critical parameters such as temperature and humidity. In particular, cleanroom cleanliness requirements specified by cleanliness class have an impact on overall energy use. A previous study covering Europe and the US reveals annual cleanroom electricity usage for cooling and fan energy varies significantly depending on cleanliness class, and may account for up to three-quarters of total annual operating costs. A study on a semiconductor cleanroom in Japan found air delivery systems account for more than 30% of total power consumption. It is evident that the main factors dictating cleanroom operation energy include airflow rates and HVAC system efficiency. Improving energy efficiency in clean rooms may potentially contribute to significant savings in the initial costs of the facilities as well as operation and maintenance costs. For example, energy consumption by a typical chip

  3. Airflow limitation is accompanied by diaphragm dysfunction.

    Science.gov (United States)

    Hellebrandová, L; Chlumský, J; Vostatek, P; Novák, D; Rýznarová, Z; Bunc, V

    2016-07-18

    Chronic airflow limitation, caused by chronic obstructive pulmonary disease (COPD) or by asthma, is believed to change the shape and the position of the diaphragm due to an increase in lung volume. We have made a comparison of magnetic resonance imaging (MRI) of diaphragm in supine position with pulmonary functions, respiratory muscle function and exercise tolerance. We have studied the differences between patients with COPD, patients with asthma, and healthy subjects. Most interestingly we found the lung hyperinflation leads to the changes in diaphragmatic excursions during the breathing cycle, seen in the differences between the maximal expiratory diaphragm position (DPex) in patients with COPD and control group (p=0.0016). The magnitude of the diaphragmatic dysfunction was significantly related to the airflow limitation expressed by the ratio of forced expiratory volume in 1 s to slow vital capacity (FEV(1)/SVC), (%, p=0.0007); to the lung hyperinflation expressed as the ratio of the residual volume to total lung capacity (RV/TLC), (%, p=0.0018) and the extent of tidal volume constrain expressed as maximal tidal volume (V(Tmax)), ([l], p=0.0002); and the ratio of tidal volume to slow vital capacity (V(T)/SVC), (p=0.0038) during submaximal exercise. These results suggest that diaphragmatic movement fails to contribute sufficiently to the change in lung volume in emphysema. Tests of respiratory muscle function were related to the position of the diaphragm in deep expiration, e.g. neuromuscular coupling (P(0.1)/V(T)) (p=0.0232). The results have shown that the lung volumes determine the position of the diaphragm and function of the respiratory muscles. Chronic airflow limitation seems to change the position of the diaphragm, which thereafter influences inspiratory muscle function and exercise tolerance. There is an apparent relationship between the position of the diaphragm and the pulmonary functions and exercise tolerance.

  4. NATURAL AIRFLOW PERFORMANCES OF DOUBLE-SKIN FACADE TYPES

    Directory of Open Access Journals (Sweden)

    IYATI Wasiska

    2014-12-01

    Full Text Available DSF (Double-Skin Facade aplications required on highrise building envelope to increase its thermal performance. The performance DSF with natural airflow, especially external air curtain mode, is affected by airflow around the building, and the design characteristics of the DSF. This paper investigated the performance of some DSF models, namely the multi-storey and box-window type, as well as those modification in utilizing natural airflow, especially with 90° wind direction toward the facade, using CFD techniques. The results showed that the multi-storey type has the best performance with higher average wind speed and equitable airflow distribution in all the facade zones.

  5. DRINKING WATER FROM DESALINATION OF SEAWATER: OPTIMIZATION OF REVERSE OSMOSIS SYSTEM OPERATING PARAMETERS

    Directory of Open Access Journals (Sweden)

    MARWAN M. SHAMEL

    2006-12-01

    Full Text Available This paper reports on the use of pilot scale membrane separation system coupled with another pilot scale plate heat exchanger to investigate the possibilities of sweetening seawater from Telok Kalong Beach, Terengganu, Malaysia. Reverse osmosis (RO membrane of a surface area of 0.5 m2 was used during the experimental runs. Experiments were conducted at different transmembrane pressures (TMP ranged from 40 to 55 bars, operation temperature ranged from 35 to 45oC, feed concentration (TDS ranged from 34900 to 52500 ppm and cross flow velocities ranged from 1.4 to 2.1 m/s. The result show that the flux values increased linearly with TMP as well as sodium ion rejection. Permeate flux values increased proportionally with the temperature and the later effect was more significant at high pressures. The temperature changing has also influenced the rejection of sodium ion. The minerals content especially NaCl and total dissolved solid (TDS in the drinking water produced in this research are conforming to the standards of World Health Organization (WHO.

  6. Optimal width of quantum well for reversed polarization blue InGaN light-emitting diodes

    Directory of Open Access Journals (Sweden)

    Junjie Kang

    2013-07-01

    Full Text Available The optical properties of reversed polarization (RP blue InGaN light-emitting diodes (LEDs under different quantum wells (QWs width are numerically studied. We compared the band diagram, electron and hole concentration, emission wavelength, radiation recombination, internal quantum efficiency (IQE, turn on voltage and light output power (LOP of these structures by numerical simulation. It found that QW width has a remarkable influence on the properties of RP blue InGaN LEDs. With the increase of QW width, the turn on voltage and radiation recombination rate decreases. It finds that the optimal width of QWs is about 3 nm at the current injection density of 15 A/cm2.

  7. Optimization of membrane stack configuration for efficient hydrogen production in microbial reverse-electrodialysis electrolysis cells coupled with thermolytic solutions.

    Science.gov (United States)

    Luo, Xi; Nam, Joo-Youn; Zhang, Fang; Zhang, Xiaoyuan; Liang, Peng; Huang, Xia; Logan, Bruce E

    2013-07-01

    Waste heat can be captured as electrical energy to drive hydrogen evolution in microbial reverse-electrodialysis electrolysis cells (MRECs) by using thermolytic solutions such as ammonium bicarbonate. To determine the optimal membrane stack configuration for efficient hydrogen production in MRECs using ammonium bicarbonate solutions, different numbers of cell pairs and stack arrangements were tested. The optimum number of cell pairs was determined to be five based on MREC performance and a desire to minimize capital costs. The stack arrangement was altered by placing an extra low concentration chamber adjacent to anode chamber to reduce ammonia crossover. This additional chamber decreased ammonia nitrogen losses into anolyte by 60%, increased the coulombic efficiency to 83%, and improved the hydrogen yield to a maximum of 3.5 mol H2/mol acetate, with an overall energy efficiency of 27%. These results improve the MREC process, making it a more efficient method for renewable hydrogen gas production.

  8. Optimization of membrane stack configuration for efficient hydrogen production in microbial reverse-electrodialysis electrolysis cells coupled with thermolytic solutions

    KAUST Repository

    Luo, Xi

    2013-07-01

    Waste heat can be captured as electrical energy to drive hydrogen evolution in microbial reverse-electrodialysis electrolysis cells (MRECs) by using thermolytic solutions such as ammonium bicarbonate. To determine the optimal membrane stack configuration for efficient hydrogen production in MRECs using ammonium bicarbonate solutions, different numbers of cell pairs and stack arrangements were tested. The optimum number of cell pairs was determined to be five based on MREC performance and a desire to minimize capital costs. The stack arrangement was altered by placing an extra low concentration chamber adjacent to anode chamber to reduce ammonia crossover. This additional chamber decreased ammonia nitrogen losses into anolyte by 60%, increased the coulombic efficiency to 83%, and improved the hydrogen yield to a maximum of 3.5mol H2/mol acetate, with an overall energy efficiency of 27%. These results improve the MREC process, making it a more efficient method for renewable hydrogen gas production. © 2013 Elsevier Ltd.

  9. On the Forming Mechanism of the Cleaning Airflow of Pulse-jet Fabric Filters.

    Science.gov (United States)

    Jiying, Cai; Wenge, Hao; Cong, Zhang; Jiaqi, Yu; Ting, Wang

    2017-04-05

    To reveal the formation mechanism of a pulse-jet airflow's cleaning effect in a filter bag, a theoretical model is built by using the theory of gas jet and unitary adiabatic flow according to given specifications and dimensions of the bags and resistance characteristics of the cloth and dust layer. It is about the relationship between cleaning system structure and operating parameters. The model follows the principle that the flow and kinetic energy of jet flow injected into a filter bag should be consistent with the flow of cleaning airflow in the bag and the pressure drop flowing through the filter cloth and dust layer. The purpose of the model is to achieve the peak pressure of cleaning airflow, which dominates the effect of the pulse-jet cleaning process. The cleaning system structure includes air pressure in the nozzle, structure and size of nozzle, exit velocity of nozzle, jet distance and diameter of jet cross-section. Based on the condition of cleaning system structure and operating parameters established by using the theoretical model, Fluent software is applied to carry out a numerical simulation of the jet airflow field at the nozzle's outlet, jet airflow field between nozzle and bag top, and cleaning airflow field in the filter bag. Experimental results are used to verify the reliability of the theoretical model. They are obtained in a pilot-scale test filter with a single bag, in length of 2m and in general full-scale dimensions of the cleaning system. The results show that when any rectification measure is not installed at the bag opening, the cross-sectional area covered by jet gas is hardly sufficient to cover the entire area of the bag opening. A large portion of the gases injected into the filter bag will overflow reversely upward from the edge due to pressure differences between the upper area and lower area inside the bag opening. This led to a serious shortage of the cleaning airflow and a limited increase in static pressure. When a venturi

  10. REVERSE ENGINEERING IN MODELING OF AIRCRAFT PROPELLER BLADE - FIRST STEP TO PRODUCT OPTIMIZATION

    Directory of Open Access Journals (Sweden)

    Muhammad Yasir Anwar

    2014-12-01

    Full Text Available ABSTRACT: Propeller aircrafts have had many ups and downs throughout their use in the aviation history. Due to the current economic recession and price hikes in fuels, propeller aircrafts may yet again be a choice for aerial transport and has thus re-emerged as an active area for research. On modern propeller aircrafts old aluminum propellers are being replaced with fiber reinforced composite propellers. However, owing to their reliability, strength, and integrity, aluminum propellers are still used in military aircrafts. One of the challenges that engineers of these aircraft-type have had to deal with is the non-availability of engineering drawings of these propellers. It is practically impossible to carry out any study, research or modification on such propellers in the absence of correct CAD data. This article proposes a methodology wherein a CAD model of a C-130 aircraft propeller blade can be constructed using reverse engineering techniques. Such a model would help in future aerodynamic as well as structural analyses which includes investigation on structural integrity and the fluid dynamics characteristics of propeller blades. Different steps involved in this process are discussed; starting from laser scanning to obtain the cloud of points data and subsequently generating a CAD model in a commercial CAD software. The model is then imported into an analysis software where quality surface meshes are generated using tetrahedral elements. The purpose is to prepare a meshed model for future computational analysis including CFD (Computational Fluid Dynamics and FE (Finite Element analysis. ABSTRAK: Pesawat bebaling mempunyai tempoh pasang surutnya sepanjang penggunaanya dalam sejarah penerbangan. Kini disebabkan oleh kemelesetan ekonomi dan kenaikan harga minyak, pesawat bebaling mungkin akan merupakan pengangkutan udara pilihan dan seterusnya muncul semula sebagai ruangan aktif penyelidikan. Pada pesawat bebaling moden, bebaling aluminium yang

  11. Design of an integrated forward and reverse logistics network optimi-zation model for commercial goods management

    Directory of Open Access Journals (Sweden)

    Eva Ponce-Cueto

    2015-01-01

    Full Text Available In this study, an optimization model is formulated for designing an integrated forward and reverse logistics network in the consumer goods industry. The resultant model is a mixed-integer linear programming model (MILP. Its purpose is to minimize the total costs of the closed-loop supply chain network. It is important to note that the design of the logistics network may involve a trade-off between the total costs and the optimality in commercial goods management. The model comprises a discrete set as potential locations of unlimited capacity warehouses and fixed locations of customers’ zones. It provides decisions related to the facility location and customers’ requirements satisfaction, all of this related with the inventory and shipment decisions of the supply chain. Finally, an application of this model is illustrated by a real-life case in the food and drinks industry. We can conclude that this model can significantly help companies to make decisions about problems associated with logistics network design.

  12. Novel Robust Optimization and Power Allocation of Time Reversal-MIMO-UWB Systems in an Imperfect CSI

    Directory of Open Access Journals (Sweden)

    Sajjad Alizadeh

    2013-03-01

    Full Text Available Time Reversal (TR technique is an attractive solution for a scenario where the transmission system employs low complexity receivers with multiple antennas at both transmitter and receiver sides. The TR technique can be combined with a high data rate MIMO-UWB system as TR-MIMO-UWB system. In spite of TR's good performance in MIMO-UWB systems, it suffers from performance degradation in an imperfect Channel State Information (CSI case. In this paper, at first a robust TR pre-filter is designed together with a MMSE equalizer in TR-MIMO-UWB system where is robust against channel imperfection conditions. We show that the robust pre-filter optimization technique, considerably improves the BER performance of TR-MIMO-UWB system in imperfect CSI, where temporal focusing of the TR technique is kept, especially for high SNR values. Then, in order to improve the system performance more than ever, a power loading scheme is developed by minimizing the average symbol error rate in an imperfect CSI. Numerical and simulation results are presented to confirm the performance advantage attained by the proposed robust optimization and power loading in an imperfect CSI scenario.

  13. Free Energy-Based Virtual Screening and Optimization of RNase H Inhibitors of HIV-1 Reverse Transcriptase

    Science.gov (United States)

    2016-01-01

    We report the results of a binding free energy-based virtual screening campaign of a library of 77 α-hydroxytropolone derivatives against the challenging RNase H active site of the reverse transcriptase (RT) enzyme of human immunodeficiency virus-1. Multiple protonation states, rotamer states, and binding modalities of each compound were individually evaluated. The work involved more than 300 individual absolute alchemical binding free energy parallel molecular dynamics calculations and over 1 million CPU hours on national computing clusters and a local campus computational grid. The thermodynamic and structural measures obtained in this work rationalize a series of characteristics of this system useful for guiding future synthetic and biochemical efforts. The free energy model identified key ligand-dependent entropic and conformational reorganization processes difficult to capture using standard docking and scoring approaches. Binding free energy-based optimization of the lead compounds emerging from the virtual screen has yielded four compounds with very favorable binding properties, which will be the subject of further experimental investigations. This work is one of the few reported applications of advanced-binding free energy models to large-scale virtual screening and optimization projects. It further demonstrates that, with suitable algorithms and automation, advanced-binding free energy models can have a useful role in early-stage drug-discovery programs. PMID:27713931

  14. Ising computation based combinatorial optimization using spin-Hall effect (SHE) induced stochastic magnetization reversal

    Science.gov (United States)

    Shim, Yong; Jaiswal, Akhilesh; Roy, Kaushik

    2017-05-01

    Ising spin model is considered as an efficient computing method to solve combinatorial optimization problems based on its natural tendency of convergence towards low energy state. The underlying basic functions facilitating the Ising model can be categorized into two parts, "Annealing and Majority vote." In this paper, we propose an Ising cell based on Spin Hall Effect (SHE) induced magnetization switching in a Magnetic Tunnel Junction (MTJ). The stochasticity of our proposed Ising cell based on SHE induced MTJ switching can implement the natural annealing process by preventing the system from being stuck in solutions with local minima. Further, by controlling the current through the Heavy-Metal (HM) underlying the MTJ, we can mimic the majority vote function which determines the next state of the individual spins. By solving coupled Landau-Lifshitz-Gilbert equations, we demonstrate that our Ising cell can be replicated to map certain combinatorial problems. We present results for two representative problems—Maximum-cut and Graph coloring—to illustrate the feasibility of the proposed device-circuit configuration in solving combinatorial problems. Our proposed solution using a HM based MTJ device can be exploited to implement compact, fast, and energy efficient Ising spin model.

  15. Airflow behavior changes in upper airway caused by different head and neck positions: Comparison by computational fluid dynamics.

    Science.gov (United States)

    Wei, Wei; Huang, Shi-Wei; Chen, Lian-Hua; Qi, Yang; Qiu, Yi-Min; Li, Shi-Tong

    2017-02-08

    The feasibility of computational fluid dynamics (CFD) to evaluate airflow characteristics in different head and neck positions has not been established. This study compared the changes in volume and airflow behavior of the upper airway by CFD simulation to predict the influence of anatomical and physiological airway changes due to different head-neck positions on mechanical ventilation. One awake volunteer with no risk of difficult airway underwent computed tomography in neutral position, extension position (both head and neck extended), and sniffing position (head extended and neck flexed). Three-dimensional airway models of the upper airway were reconstructed. The total volume (V) and narrowest area (Amin) of the airway models were measured. CFD simulation with an Spalart-Allmaras model was performed to characterize airflow behavior in neutral, extension, and sniffing positions of closed-mouth and open-mouth ventilation. The comparison result for V was neutral airflow rate. In sniffing position, pressure differences decreased and velocity remained almost constant. Recirculation airflow was generated near the subglottic region in neutral and extension positions. Sniffing position improves airway patency by increasing airway volume and decreasing airway resistance, suggesting that sniffing position may be the optimal choice for mask ventilation.

  16. Reconstruction of sound source signal by analytical passive TR in the environment with airflow

    Science.gov (United States)

    Wei, Long; Li, Min; Yang, Debin; Niu, Feng; Zeng, Wu

    2017-03-01

    In the acoustic design of air vehicles, the time-domain signals of noise sources on the surface of air vehicles can serve as data support to reveal the noise source generation mechanism, analyze acoustic fatigue, and take measures for noise insulation and reduction. To rapidly reconstruct the time-domain sound source signals in an environment with flow, a method combining the analytical passive time reversal mirror (AP-TR) with a shear flow correction is proposed. In this method, the negative influence of flow on sound wave propagation is suppressed by the shear flow correction, obtaining the corrected acoustic propagation time delay and path. Those corrected time delay and path together with the microphone array signals are then submitted to the AP-TR, reconstructing more accurate sound source signals in the environment with airflow. As an analytical method, AP-TR offers a supplementary way in 3D space to reconstruct the signal of sound source in the environment with airflow instead of the numerical TR. Experiments on the reconstruction of the sound source signals of a pair of loud speakers are conducted in an anechoic wind tunnel with subsonic airflow to validate the effectiveness and priorities of the proposed method. Moreover the comparison by theorem and experiment result between the AP-TR and the time-domain beamforming in reconstructing the sound source signal is also discussed.

  17. Subsurface Airflow Induced by Natural Forcings

    Institute of Scientific and Technical Information of China (English)

    Jiu J. Jiao; LI Hai-long

    2004-01-01

    Subsurface air flow can be induced by natural processes, such as atmospheric or barometric pressure changes, water table fluctuations, topographic effects, and rainfall infiltration. Barometric pressure fluctuations are the most common cause of subsurface air flow, which can be significant under favourable geological conditions. This process has been studied most extensively because of its application to passive soil vapor extraction. Soil air flow induced by water table fluctuations can be significant, particularly where the fluctuations are of high frequency, for example, in tidal-influenced coastal areas. Topographic effects can lead to strong subsoil air flow in areas with great elevation differences. Rainfall infiltration usually produces only weak airflow. Air flow induced by these natural processes has important environmental and engineering implications. Among the different processes, air flow induced by tidal fluctuations has been studied the least, although it has exciting applications to coastal engineering projects and environmental remediation.

  18. Unraveling the Pathophysiology of the Asthma-COPD Overlap Syndrome: Unsuspected Mild Centrilobular Emphysema Is Responsible for Loss of Lung Elastic Recoil in Never Smokers With Asthma With Persistent Expiratory Airflow Limitation.

    Science.gov (United States)

    Gelb, Arthur F; Yamamoto, Alfred; Verbeken, Eric K; Nadel, Jay A

    2015-08-01

    Investigators believe most patients with asthma have reversible airflow obstruction with treatment, despite airway remodeling and hyperresponsiveness. There are smokers with chronic expiratory airflow obstruction despite treatment who have features of both asthma and COPD. Some investigators refer to this conundrum as the asthma-COPD overlap syndrome (ACOS). Furthermore, a subset of treated nonsmokers with moderate to severe asthma have persistent expiratory airflow limitation, despite partial reversibility. This residuum has been assumed to be due to large and especially small airway remodeling. Alternatively, we and others have described reversible loss of lung elastic recoil in acute and persistent loss in patients with moderate to severe chronic asthma who never smoked and its adverse effect on maximal expiratory airflow. The mechanism(s) responsible for loss of lung elastic recoil and persistent expiratory airflow limitation in nonsmokers with chronic asthma consistent with ACOS remain unknown in the absence of structure-function studies. Recently we reported a new pathophysiologic observation in 10 treated never smokers with asthma with persistent expiratory airflow obstruction, despite partial reversibility: All 10 patients with asthma had a significant decrease in lung elastic recoil, and unsuspected, microscopic mild centrilobular emphysema was noted in all three autopsies obtained although it was not easily identified on lung CT scan. These sentinel pathophysiologic observations need to be confirmed to further unravel the epiphenomenon of ACOS. The proinflammatory and proteolytic mechanism(s) leading to lung tissue breakdown need to be further investigated.

  19. CFD simulation and optimization of airflow field in industrial tunnel dryer with different blowing designs%不同进风方案下隧道烘干窑热风流场CFD模拟和优化

    Institute of Scientific and Technical Information of China (English)

    师建芳; 吴中华; 刘清; 娄正; 赵玉强; 朱明

    2014-01-01

    this work provide a reference for the optimization design of the air inlet structure of the tunnel dryers.

  20. ROBUSTNESS TESTING OF AN OPTIMIZED REVERSED-PHASE HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHIC SYSTEM FOR THE SEPARATION OF 6 SULFONAMIDES USING THE RULES OF ERROR PROPAGATION

    NARCIS (Netherlands)

    WIELING, J; COENEGRACHT, PMJ; DOORNBOS, DA; JONKMAN, JHG

    1993-01-01

    In a previous investigation, the composition of the mobile phase for the reversed-phase HPLC separation of twelve sulphonamides was optimized. The predicted chromatogram showed great similarity with a chromatogram measured under optimum conditions. For routine analysis, it is important to have robus

  1. Optimization and Validation of a Real Time Reverse Transcriptase Polymerase Chain Reaction with RNA Internal Control to Detect Rubella RNA

    Directory of Open Access Journals (Sweden)

    Winny Xie

    2013-12-01

    Full Text Available BACKGROUND: According to a report from WHO, cases of rubella infection in Indonesia has increased up to 10-fold from 2007 to 2011. Despite no data of congenital rubella syndrome in the report, there are approximately 45,000 cases of babies born with heart failure and 0.1-0.3% live births with congenital deafness in Indonesia. Allegedly, rubella infection during pregnancy may play a role in this condition. This study aimed to optimize and validate a real-time reverse transcriptase polymerase chain reaction (RT-qPCR method to detect rubella virus RNA as an aid for the diagnosis of congenital rubella infection. METHODS: Method optimization was conducted using nucleic acids extracted from Trimovax Merieux vaccine with the High Pure Viral Nucleic Acid Kit. One step RT-qPCR was performed with Quantifast Multiplex RTPCR+R Kit. Target synthetic DNA was designed and used to determine the sensitivity of the method. RNA internal control was synthesized to control the process of extraction and amplification. RESULTS: The analytical sensitivity of this method was as low as 5 copies target synthetic DNA/μl. The mean Coefficient of Variation (CV % of the critical threshold (Ct obtained were 2.71%, 1.20%, 1.62%, and 1.59% for within run, between run, between kit lots, and between operators, respectively. Recovery of the target synthetic DNA from amniotic fluid was 100.51% (by the log copies/μl at the concentration of 1,000,000 copies/μl. CONCLUSIONS: RT-qPCR is successfully used for the detection of rubella virus RNA in vaccine and synthetic nucleic acid. With its high sensitivity, good precision and recovery, this method offers a means to improve the diagnosis of congenital rubella infection in developing countries like Indonesia. KEYWORDS: congenital rubella, RT-qPCR, prenatal diagnosis, amniotic fluid.

  2. Reversed-phase dispersive liquid-liquid microextraction with central composite design optimization for preconcentration and HPLC determination of oleuropein.

    Science.gov (United States)

    Hashemi, Payman; Raeisi, Fatemeh; Ghiasvand, Ali Reza; Rahimi, Akram

    2010-03-15

    A reversed-phase dispersive liquid-liquid microextraction (RP-DLLME) method was developed for the preconcentration and direct HPLC determination of oleuropein in olive's processing wastewater (OPW) and olive leaves extracts. In conventional DLLME, the sedimented phase is a micro-drop of a chlorinated organic solvent that is not compatible with RP-HPLC. Therefore, solvent evaporation and reconstitution with an appropriate solvent is often required. In RP-DLLME, this problem was overcome by overturning the solvent polarity in the ordinary DLLME and replacing the organic solvent with water. A central composite chemometrics design was used for multivariate optimization of the effects of five different parameters influencing the extraction efficiency of the method. In the optimized conditions, a mixture of 1.4 mL of an ethyl acetate extract of sample and 40 microL water (pH 5.0) was rapidly injected into 5.3 mL of cyclohexane. After centrifugation of the formed cloudy mixture, a micro-drop of the aqueous phase was sedimented at the conical bottom of the centrifuge tube. This phase, that contained the preconcentrated and partially purified analyte, was directly injected into an RP-HPLC column for analysis. A mean extraction recovery of 102.5 (+/-4.5) % with enrichment factors exceeding 38, was obtained for five replicated analysis. The detection limit of the method (3 sigma) for OE was 0.02 microg L(-1) for OPW and 2 x 10(-3) mg kg(-1) for olive leaves samples. The results showed that, RP-DLLME is a promising technique which is quick, easily operated and can be directly coupled to HPLC.

  3. Process optimization in postcombustion CO{sub 2}-capture by means of repowering and reversible carbonation/calcination cycle

    Energy Technology Data Exchange (ETDEWEB)

    Luis M. Romeo; Juan C. Abanades; Juan C. Ballesteros; Antonio Valero; Jesus M. Escosa; Antonio Gimenez; Cristobal Cortes; Jara Pano [Centro de Investigacion Recursos y Consumos Energeticos (CIRCE), Zaragoza (Spain)

    2006-07-01

    Coal is the major power generation fuel for electricity production. Many countries are heavily dependent on coal, that contributes to about 30% of the European power generation and plays an important role in the European generation industry. The existing coal power plants must be operative to provide energy and take advantage of local resources, but it is necessary to reduce their CO{sub 2} emissions in a feasible manner. It means without introducing excessive economic penalty or reducing their capacity and efficiency. In order to achieve this objective two strategies are highlighted, increase power plant efficiency and capture CO{sub 2} emissions. Increasing power plant efficiency is one of the less expensive ways to reduce CO{sub 2} emissions however it is neither an easy task for existing power plant nor efficiency improvements are large enough to achieve important CO{sub 2} emissions reduction. One of the best methods to significantly increase plant efficiency and also energy production from an economic standpoint is repowering. On the other hand, it is generally accepted that postcombustion CO{sub 2} capture is one of the best suitable technologies for existing coal power plants. It is also well-know that one of the most important gaps in postcombustion capture is the necessity of achieve a process optimization for large-scale power plants. One of these technologies involves the separation of CO{sub 2} from high temperature flue gases using the reversible carbonation reaction of CaO and the calcination of CaCO{sub 3}. In order to achieve a significant abatement of CO{sub 2} emissions without excessive penalty in power plant efficiency, generating capacity and with CO{sub 2} capture cost below 25 EUR/Ton CO{sub 2}, this paper proposes a new, feasible approach to join these two concepts by an optimal integration of the processes within an existing power plant. 6 refs., 1 fig., 2 tabs.

  4. Neural representations of airflow in Drosophila mushroom body.

    Directory of Open Access Journals (Sweden)

    Akira Mamiya

    Full Text Available The Drosophila mushroom body (MB is a higher olfactory center where olfactory and other sensory information are thought to be associated. However, how MB neurons of Drosophila respond to sensory stimuli other than odor is not known. Here, we characterized the responses of MB neurons to a change in airflow, a stimulus associated with odor perception. In vivo calcium imaging from MB neurons revealed surprisingly strong and dynamic responses to an airflow stimulus. This response was dependent on the movement of the 3(rd antennal segment, suggesting that Johnston's organ may be detecting the airflow. The calyx, the input region of the MB, responded homogeneously to airflow on. However, in the output lobes of the MB, different types of MB neurons responded with different patterns of activity to airflow on and off. Furthermore, detailed spatial analysis of the responses revealed that even within a lobe that is composed of a single type of MB neuron, there are subdivisions that respond differently to airflow on and off. These subdivisions within a single lobe were organized in a stereotypic manner across flies. For the first time, we show that changes in airflow affect MB neurons significantly and these effects are spatially organized into divisions smaller than previously defined MB neuron types.

  5. Intensification of the Reverse Cationic Flotation of Hematite Ores with Optimization of Process and Hydrodynamic Parameters of Flotation Cell

    Science.gov (United States)

    Poperechnikova, O. Yu; Filippov, L. O.; Shumskaya, E. N.; Filippova, I. V.

    2017-07-01

    The demand of high grade iron ore concentrates is a major issue due to the depletion of rich iron-bearing ores and high competitiveness in the iron ore market. Iron ore production is forced out to upgrade flowsheets to decrease the silica content in the pelettes. Different types of ore have different mineral composition and texture-structural features which require different mineral processing methods and technologies. The paper presents a comparative study of the cationic and anionic flotation routes to process a fine-grain oxidized iron ore. The modified carboxymethyl cellulose was found as the most efficient depressant in reverse cationic flotation. The results of flotation optimization of hematite ores using matrix of second-order center rotatable uniform design allowed to define the collector concentration, impeller rotation speed and air flowrate as the main flotation parameters impacting on the iron ore concentrate quality and iron recovery in a laboratory flotation machine. These parameters have been selected as independent during the experiments.

  6. Locating air samplers inside a room using qualitative airflow studies

    Energy Technology Data Exchange (ETDEWEB)

    Kravchik, T.; Levinson, S.; German, U. [Nuclear Research Center Negev, Beer-Sheva (Israel); Haim, M. [Ben-Gurion University of the Negev, Beer-Sheva (Israel)

    2000-05-01

    The concentration of airborne radioactive materials inside a room can vary widely from one location to another, sometimes by orders of magnitude even for locations that are reactively close. Inappropriately placed air samplers can give misleading results and, therefore, the location of air samplers is important. Proper placement of samplers is not always obvious and cannot be determined simply by observing the position of room air supply and exhaust vents. Airflow studies, such as the release of smoke aerosols, should be used. The significance of airflow pattern studies depends on the purpose of sampling-for estimating worker intakes, warning of abnormally high concentrations, defining airborne radioactive areas, testing for confinement of sealed radioactive materials, etc. Qualitative smoke tests were conducted inside rooms using a 'KUPO Inc.' smoke tube (D5050 fog machine). Smoke was released at elevation of 1-2 meters and its path was recorded on worksheet drawings of the room. The tests revealed three types of airflow patterns inside the rooms: a) flow path with a definite stable direction, b) flow path which changes direction arbitrarily as a result of airflow vortices, and c) static/stagnant air. In some cases the airflow path direction was different from the expected one. This emphasizes the significance of conducting airflow studies for location of air samplers and not only relying on intuition. An airflow patterns comparison study between the qualitative smoke tests and computer simulation using a commercial finite element CFD code, FIDAP 8.01, was also conducted. The measured and the computed paths of the airflow were mostly in good agreement. The computer simulation indicated additional details which could not be observed when performing the smoke tests because of physical and visibility limitations. (author)

  7. Airflow-Restricting Mask Reduces Acute Performance in Resistance Exercise

    OpenAIRE

    Yuri L. Motoyama; Gustavo B. Joel; Paulo E. A. Pereira; Gilmar J. Esteves; Azevedo, Paulo H.S.M.

    2016-01-01

    Background: The aim of this study was to compare the number of repetitions to volitional failure, the blood lactate concentration, and the perceived exertion to resistance training with and without an airflow-restricting mask. Methods: Eight participants participated in a randomized, counterbalanced, crossover study. Participants were assigned to an airflow-restricting mask group (MASK) or a control group (CONT) and completed five sets of chest presses and parallel squats until failure at 75%...

  8. Airflow-induced triboelectric nanogenerator as a self-powered sensor for detecting humidity and airflow rate.

    Science.gov (United States)

    Guo, Hengyu; Chen, Jie; Tian, Li; Leng, Qiang; Xi, Yi; Hu, Chenguo

    2014-10-08

    Humidity sensors are commonly based on the resistance change of metal oxide semiconductors, which show high sensitivity in low humidity but low sensitivity in high humidity. In this work, we design a novel humidity sensor based on the airflow-induced triboelectric nanogenerator (ATNG) that can serve as a self-powered sensor to detect humidity (especially in high humidity) and airflow rate. The output current or voltage change is investigated under different humidity (20-100% relative humidity) at fixed airflow rate and different airflow rates (15-25 L/min) at a fixed humidity. The working principle of the ATNG-based sensor is illustrated. We find that both output current and voltage can serve as a variable for detecting humidity, while only the output current can serve as a variable for determining airflow rate. Our study demonstrates an innovative approach toward detection of humidity and airflow rate with advantages of self-power, multifunction, low cost, simple fabrication, and high sensitivity.

  9. Cost-benefit Optimization Analysis of Reverse Logistics%逆向物流成本收益优化分析

    Institute of Scientific and Technical Information of China (English)

    潘永明; 单晓龙; 段云鑫

    2015-01-01

    With the rise and the development of e-commerce, reverse logistics is becoming a new way of sustainable development for enterprises. In recent years, the concept of sustainable development makes the reverse logistics popular in academia and industry. Based on the analysis on the concept of reverse logistics, the paper analyzes Structure of reverse logistics cost and benefits and discusses how to build a cost-benefit optimization mode of reverse logistics. Finally, the paper puts forward reasonable programs according to it.%伴随电子商务的兴起以及发展,逆向物流正成为企业获得可持续发展的新方式。近年来,可持续发展理念的贯穿使得逆向物流在学术界和企业界流行起来。本文在分析逆向物流概念的基础上,对逆向物流的成本以及收益进行了分析,并探讨了逆向物流的成本收益优化模型,并以此给出合理的可行性建议。

  10. Pigeons Show Near-Optimal Win-Stay/Lose-Shift Performance on a Simultaneous-Discrimination, Midsession Reversal Task with Short Intertrial Intervals

    Science.gov (United States)

    Rayburn-Reeves, Rebecca M.; Laude, Jennifer R.; Zentall, Thomas R.

    2013-01-01

    Discrimination reversal tasks have been used as a measure of species flexibility in dealing with changes in reinforcement contingency. The simultaneous-discrimination, midsession reversal task is one in which one stimulus (S1) is correct for the first 40 trials of an 80-trial session and the other stimulus (S2) is correct for the remaining trials. After many sessions of training with this task, pigeons show a curious pattern of choices. They begin to respond to S2 well before the reversal point (they make anticipatory errors) and they continue to respond to S1 well after the reversal (they make perseverative errors). That is, they appear to be using the passage of time or number of trials into the session as a cue to reverse. We tested the hypothesis that these errors resulted in part from a memory deficit (the inability to remember over the intertrial interval, ITI, both the choice on the preceding trial and the outcome of that choice) by manipulating the duration of the ITI (1.5, 5, and 10 s). We found support for the hypothesis as pigeons with a short 1.5-s ITI showed close to optimal win-stay/lose-shift accuracy. PMID:23123672

  11. Effect of Airflows on Repetitive Nanosecond Volume Discharges

    Science.gov (United States)

    Tang, Jingfeng; Wei, Liqiu; Huo, Yuxin; Song, Jian; Yu, Daren; Zhang, Chaohai

    2016-03-01

    Atmospheric pressure discharges excited by repetitive nanosecond pulses have attracted significant attention for various applications. In this paper, a plate-plate discharge with airflows is excited by a repetitive nanosecond pulse generator. Under different experiment conditions, the applied voltages, discharge currents, and discharge images are recorded. The plasma images presented here indicate that the volume discharge modes vary with airflow speeds, and a diffuse and homogeneous volume discharge occurs at the speed of more than 35 m/s. The role of airflows provides different effects on the 2-stage pulse discharges. The 1st pulse currents nearly maintain consistency for different airflow speeds. However, the 2nd pulse current has a change trend of first decreasing and then rapidly increasing, and the value difference for 2nd pulse currents is about 20 A under different airflows. In addition, the experimental results are discussed according to the electrical parameters and discharge images. supported by National Natural Science Foundation of China (Nos. 51006027, 51437002, and 51477035)

  12. Evaluation of airflow patterns following procedures established by NUREG-1400.

    Science.gov (United States)

    Fritz, Brad G; Khan, Fenton; Mendoza, Donaldo P

    2006-08-01

    The U.S. Nuclear Regulatory Commission's guide, NUREG-1400, addresses many aspects of air sampling in the work place. Here, we present detailed examples of the methodology used to conduct two qualitative airflow studies at different sites. In one test, smoke was used to evaluate the airflow patterns within a high-bay building for the purpose of determining appropriate locations for air monitoring equipment. The study revealed a stagnant layer of the air within the transfer area that made predicting movement of contamination within the transfer area difficult. Without conducting an airflow study, the stagnant layer may not have been identified and could have resulted in placement of samplers at inappropriate locations. In a second test, smoke was used to verify the effectiveness of an air space barrier curtain. The results showed that the curtain adequately separated the two air spaces. The methodology employed in each test provided sound, easy to interpret information that satisfied the requirements of each test. The methods described in this article can be applied at most facilities where determination of airflow patterns or the verification of suspected airflow patterns is required.

  13. 端塞式反向器的优化设计与研究%Optimal Design and Research of End Plug Type Reverser

    Institute of Scientific and Technical Information of China (English)

    樊伟; 郝大贤; 李晓; 王科社; 查初亮

    2015-01-01

    反向器的优劣直接影响到滚珠丝杠副的使用性能,而回珠曲线是影响滚珠丝杠副性能的关键因素。文中通过对反向器进行力学分析,得出一种新型的滚珠丝杠副反向器的回珠曲线,并对此设计曲线在ADAMS中进行仿真分析,对比分析优化前后端塞式滚珠丝杠副反向器的运动情况,结果表明优化后的多段圆弧式反向器与滚珠的碰撞力明显减小,大大提高了滚珠丝杠副反向器的流畅性。%Reversers quality directly affects the performance of ball screw pair ,and the ball curve is the key factors that affect the performance of ball screw pair. This article analyzes the mechanics of the reverser and obtains a new type of ball curve of the ball screw pair of reverser. The simulation of the design curve is carried out using ADAMS to compare movement situation of end plug type ball screw pair of reverser before and after optimization, the results show that the optimized multistage arc reverser and ball collision force decreased greatly, the ball screw pair of reverser fluency is greatly improved.

  14. Study on application and numerical simulation of the airflow temperature distribution rule in drifting tunnel

    Institute of Scientific and Technical Information of China (English)

    李孝东; 卢国斌; 张浪; 周西华

    2003-01-01

    According to the law of conservation in the state of turbulent flow, the differential equation describing the airflow temperature distribution in drifting tunnel is derived, By theoretical analysis and field measurement of the airflow and thermal process in mine, theoretical analysis and systematic flow are developed. By PHONENICS program, the numerical simulation is processed, and the changing rule of airflow temperature with various parameters in drifting tunnel is derived. The airflow temperature in drifting tunnel decreases as the airflow velocity increases in a way of negative power exponent, and elevates linearly as the temperature of the incoming airflow elevates.

  15. Reducing airflow energy use in multiple zone vav systems

    Science.gov (United States)

    Tukur, Ahmed Gidado

    Variable Air Volume (VAV) systems are the most popular HVAC systems in commercial buildings. VAV systems are designed to deliver airflows at design conditions which only occur for a few hours in a year. Minimizing energy use in VAV systems requires reducing the amount of airflow delivered through the system at part load conditions. Air Handling Unit (AHU) fans are the major drivers of airflow in VAV systems and installing a Variable Frequency Drive (VFD) is the most common method of regulating airflow in VAV systems. A VFD drive does not necessarily save energy without use of an appropriate control strategy. Static pressure reset (SPR) is considered to be the most energy efficient control strategy for AHU fans with VFDs installed. The implementation of SPR however has many challenges; for example, rogue zones--zones which have faulty sensors or failed controls and actuators, system dynamics like hunting and system diversity. By investigating the parameters associated with the implementation of SPR in VAV systems, a new, improved, more stable SPR algorithm was developed and validated. This approach was further improved using Fault Detection and Diagnostics (FDD) to eliminate rogue zones. Additionally, a CO2-Demand Control Ventilation (DCV) based minimum airflow control was used to further reduce ventilation airflow and save more energy from SPR. Energy savings ranging from 25% to 51% were recorded in actual buildings with the new SPR algorithm. Finally, a methodology that utilizes historical VAV data was developed to estimate the potential savings that could be realized using SPR. The approach employed first determines an effective system loss coefficient as a function of mean damper position using the historical duct static pressure, VAV damper positions and airflows. Additionally, the historical data is used to identify the maximum mean duct damper position realizable as a result of insuring a sufficient number of VAVs are fully open at any time. Savings are

  16. Clearance of viscoelastic mucus simulant with airflow in a rectangular channel, an experimental study.

    Science.gov (United States)

    Hassan, Amgad A; Evrensel, Cahit A; Krumpe, Peter E

    2006-01-01

    Interaction of mucus simulant with airflow in a rectangular channel is investigated experimentally. Two different viscoelastic gel mucus simulants are prepared by cross linking Borax with Locust Bean Gum (LBG) solution; liquid-like (LM) with lower storage modulus and semi-solid (SM). The rheological difference between LM and SM represent the qualitative change from liquid-like healthy mucus to the one with higher storage modulus found in a person with lung disease. The study concentrates on the effect of viscoelastic layer thickness and rheology on the wave formation and clearance due to its interaction with airflow. The results indicate that the onset air velocity for wave initiation reduces by increasing layer thickness. This effect is more pronounced for SM. Slowly propagating waves initiate at a lower air velocity for LM compared to SM for thinner layer thickness and this behavior reverses for a thicker layer. Although SM clears at a critical air velocity, LM does not show clearance behavior, defined as separation of layer section from rest and movement in the downstream flow direction. This seems to suggest that thicker mucus with higher elastic modulus, similar to the mucus for a person with lung disease, may clear easier with a two-phase air-liquid flow, as in cough.

  17. MORE: mixed optimization for reverse engineering--an application to modeling biological networks response via sparse systems of nonlinear differential equations.

    Science.gov (United States)

    Sambo, Francesco; de Oca, Marco A Montes; Di Camillo, Barbara; Toffolo, Gianna; Stützle, Thomas

    2012-01-01

    Reverse engineering is the problem of inferring the structure of a network of interactions between biological variables from a set of observations. In this paper, we propose an optimization algorithm, called MORE, for the reverse engineering of biological networks from time series data. The model inferred by MORE is a sparse system of nonlinear differential equations, complex enough to realistically describe the dynamics of a biological system. MORE tackles separately the discrete component of the problem, the determination of the biological network topology, and the continuous component of the problem, the strength of the interactions. This approach allows us both to enforce system sparsity, by globally constraining the number of edges, and to integrate a priori information about the structure of the underlying interaction network. Experimental results on simulated and real-world networks show that the mixed discrete/continuous optimization approach of MORE significantly outperforms standard continuous optimization and that MORE is competitive with the state of the art in terms of accuracy of the inferred networks.

  18. Strategy for Airflow Control of Cathode in Proton Exchange Membrane Fuel Cell

    Institute of Scientific and Technical Information of China (English)

    LI Lei; LI Xiao-jing

    2008-01-01

    There are two important objectives for airflow control in proton exchange membrane fuel cells(PEMFCs). One is to keep the desired excess ratio(to provide sufficient reactant airflow) to ensure fast transient response and to minimize auxiliary power consumption, and the other one is to control the cathode pressure in stack within an acceptable range. In reality, the big inertia of stack's airflow-supplying activator limits the bandwidth of air-flow supply loop, which makes the first objective difficult to achieve, and another difficulty is that airflow is coupled with the cathode pressure in stack, which make it uneasy to keep the pressure unchanged in case of airflow perturbation. In order to overcome these difficulties, three dependant controllers are presented in this paper to control airflow, decouple the cathode pressure in stack from airflow and stabilize the cat hode pressure in stack respectively. The effectiveness of these controllers is proven by subsequent simulation and test results.

  19. Numerical simulation of the optimal two-mode attacks for two-way continuous-variable quantum cryptography in reverse reconciliation

    Science.gov (United States)

    Zhang, Yichen; Li, Zhengyu; Zhao, Yijia; Yu, Song; Guo, Hong

    2017-02-01

    We analyze the security of the two-way continuous-variable quantum key distribution protocol in reverse reconciliation against general two-mode attacks, which represent all accessible attacks at fixed channel parameters. Rather than against one specific attack model, the expression of secret key rates of the two-way protocol are derived against all accessible attack models. It is found that there is an optimal two-mode attack to minimize the performance of the protocol in terms of both secret key rates and maximal transmission distances. We identify the optimal two-mode attack, give the specific attack model of the optimal two-mode attack and show the performance of the two-way protocol against the optimal two-mode attack. Even under the optimal two-mode attack, the performances of two-way protocol are still better than the corresponding one-way protocol, which shows the advantage of making double use of the quantum channel and the potential of long-distance secure communication using a two-way protocol.

  20. Characterization of the Airflow from a Bottom Hung Window under Natural Ventilation

    DEFF Research Database (Denmark)

    Svidt, Kjeld; Heiselberg, Per; Nielsen, Peter V.

    This paper describes the results of laboratory measurements of the airflow from a bottom hung window mounted near the ceiling of a ventilated room. In the laboratory set-up it was possible to control the temperature difference and the airflow rate through the window. The pressure drop through the...... the window was measured as well as the velocity distribution in the incoming airflow. Airflow patterns and penetration depth of a cold jet were studied with smoke visualisation....

  1. Integration of a Multizone Airflow Model into a Thermalsimulation Program

    DEFF Research Database (Denmark)

    Jensen, Rasmus Lund; Sørensen, Karl Grau; Heiselberg, Per

    2007-01-01

    a methodology adopted from water distribution network that automatically sets up the independent loops and is easy to implement into a computer program. Finally an example of verification of the model is given which demonstrates the ability of the models to accurately predict the airflow of a simple multizone...

  2. Airflow Interaction Interface: Playful 3-D CAD and Gaming

    NARCIS (Netherlands)

    Wendrich, Robert E.

    2016-01-01

    This paper describes the vision and development of a tangible user interface (TUI) that allows ‘glassblowing-like’ interaction (IA) with a computer. The premise is that human fidelity in exerting pressure and airflow (i.e. breathing, blowing) could stimulate intuition, creative processing, and affor

  3. Compensation of airflow maldistribution in fin-and-tube evaporators

    DEFF Research Database (Denmark)

    Kærn, Martin Ryhl; Tiedemann, Thomas

    2012-01-01

    Compensation of airflow maldistribution in fin-and tube evaporators for residential air-conditioning is investigated with regards to circuitry design and control of individual channel superheats. In particularly, the interlaced and the face split circuitry designs are compared numerically using...

  4. Influence of furnishing on indoor airflow near external walls

    DEFF Research Database (Denmark)

    Mortensen, Lone Hedegaard; Rode, Carsten; Peuhkuri, Ruut

    2008-01-01

    Simulations of indoor environments in buildings are usually performed assuming uniform distribution of temperature and humidity of the indoor air, such as it would be in an idealised unfurnished room. The flow patterns near external walls may however be very different from the undisturbed airflow...

  5. Airflow-Restricting Mask Reduces Acute Performance in Resistance Exercise

    Directory of Open Access Journals (Sweden)

    Yuri L. Motoyama

    2016-09-01

    Full Text Available Background: The aim of this study was to compare the number of repetitions to volitional failure, the blood lactate concentration, and the perceived exertion to resistance training with and without an airflow-restricting mask. Methods: Eight participants participated in a randomized, counterbalanced, crossover study. Participants were assigned to an airflow-restricting mask group (MASK or a control group (CONT and completed five sets of chest presses and parallel squats until failure at 75% one-repetition-maximum test (1RM with 60 s of rest between sets. Ratings of perceived exertion (RPEs, blood lactate concentrations (Lac−, and total repetitions were taken after the training session. Results: MASK total repetitions were lower than those of the CONT, and (Lac− and MASK RPEs were higher than those of the CONT in both exercises. Conclusions: We conclude that an airflow-restricting mask in combination with resistance training increase perceptions of exertion and decrease muscular performance and lactate concentrations when compared to resistance training without this accessory. This evidence shows that the airflow-restricting mask may change the central nervous system and stop the exercise beforehand to prevent some biological damage.

  6. Airflow energy harvesting with high wind velocities for industrial applications

    Science.gov (United States)

    Chew, Z. J.; Tuddenham, S. B.; Zhu, M.

    2016-11-01

    An airflow energy harvester capable of harvesting energy from vortices at high speed is presented in this paper. The airflow energy harvester is implemented using a modified helical Savonius turbine and an electromagnetic generator. A power management module with maximum power point finding capability is used to manage the harvested energy and convert the low voltage magnitude from the generator to a usable level for wireless sensors. The airflow energy harvester is characterized using vortex generated by air hitting a plate in a wind tunnel. By using an aircraft environment with wind speed of 17 m/s as case study, the output power of the airflow energy harvester is measured to be 126 mW. The overall efficiency of the power management module is 45.76 to 61.2%, with maximum power point tracking efficiency of 94.21 to 99.72% for wind speed of 10 to 18 m/s, and has a quiescent current of 790 nA for the maximum power point tracking circuit.

  7. Investigation of the drying airflow at a newly developed dryer geometry for mixed flow grain dryers

    Directory of Open Access Journals (Sweden)

    Holger Scaar

    2016-06-01

    Full Text Available The mixed-flow dryer has been a matter of investigation many times regarding drying efficiency, dryer control, and performance enhancement over the past years. However, there is still considerable demand for optimization in terms of energy efficiency and homogeneity of drying. In order to analyze the specific energy consumption and the homogeneity of the drying process, different thermodynamic process conditions have been investigated for the conventional MFD design using numerical and experimental methods. Based on the results obtained, a novel dryer design has been developed. With this, a considerable increase of efficiency is expected. As the fluid dynamic analysis of the first design draft revealed, further development is required until scaling-up and transfer into practice will be possible. While homogeneous airflow conditions could be demonstrated in the core flow region in the center of the dryer, the configuration must be optimized in the near wall regions.

  8. Optimization of UV-LED curable printing material for applications in direct writing systems: Inkjet, reverse offset, and micro dispensing GPD

    Science.gov (United States)

    Varela, Ada Judith Ortega

    The quality of a product fabricated by direct writing methods will depend greatly on the properties of the printing material and its compatibility with the printing process. Although multiple advances in developing printing inks and pastes with novel properties are being made, the potential those can bring to electronics is hindered by their stability and performance during the printing process. In this study a UV-LED curable acrylic material was used to test the optimization of inks and pastes for three of the most common direct writing systems: Piezo-type Inkjet, Reverse Offset Roll to Plate, and Micro Deposition. The viscosity of the photosensitive acrylic matrix was controlled by either the addition of diluents or electronically functional reinforcement material. The contact angle of the optimized solutions on 16 different Polyester, Polyimide, and Paper films was observed. Solutions with larger contact angles showed better line definition for the Inkjet and the Micro Dispense systems. In addition to the contact angle differential, the rheological properties showed to be a determinant factor for the feasibility of a solution to undergo the reverse offset printing process. The UV curable acrylic demonstrated electrical conductivity when 2% (wt.) MWCNT were ultrasonically mixed in the matrix and then cured with a 385nm wavelength for 3 seconds. Only the micro deposition system was capable of printing the acrylic-MWCNT paste and the relationship between the contact angle, pattern accuracy, substrate selection, and electrical conductivity, was determined.

  9. Collective odor source estimation and search in time-variant airflow environments using mobile robots.

    Science.gov (United States)

    Meng, Qing-Hao; Yang, Wei-Xing; Wang, Yang; Zeng, Ming

    2011-01-01

    This paper addresses the collective odor source localization (OSL) problem in a time-varying airflow environment using mobile robots. A novel OSL methodology which combines odor-source probability estimation and multiple robots' search is proposed. The estimation phase consists of two steps: firstly, the separate probability-distribution map of odor source is estimated via Bayesian rules and fuzzy inference based on a single robot's detection events; secondly, the separate maps estimated by different robots at different times are fused into a combined map by way of distance based superposition. The multi-robot search behaviors are coordinated via a particle swarm optimization algorithm, where the estimated odor-source probability distribution is used to express the fitness functions. In the process of OSL, the estimation phase provides the prior knowledge for the searching while the searching verifies the estimation results, and both phases are implemented iteratively. The results of simulations for large-scale advection-diffusion plume environments and experiments using real robots in an indoor airflow environment validate the feasibility and robustness of the proposed OSL method.

  10. Collective Odor Source Estimation and Search in Time-Variant Airflow Environments Using Mobile Robots

    Directory of Open Access Journals (Sweden)

    Wei-Xing Yang

    2011-11-01

    Full Text Available This paper addresses the collective odor source localization (OSL problem in a time-varying airflow environment using mobile robots. A novel OSL methodology which combines odor-source probability estimation and multiple robots’ search is proposed. The estimation phase consists of two steps: firstly, the separate probability-distribution map of odor source is estimated via Bayesian rules and fuzzy inference based on a single robot’s detection events; secondly, the separate maps estimated by different robots at different times are fused into a combined map by way of distance based superposition. The multi-robot search behaviors are coordinated via a particle swarm optimization algorithm, where the estimated odor-source probability distribution is used to express the fitness functions. In the process of OSL, the estimation phase provides the prior knowledge for the searching while the searching verifies the estimation results, and both phases are implemented iteratively. The results of simulations for large-scale advection–diffusion plume environments and experiments using real robots in an indoor airflow environment validate the feasibility and robustness of the proposed OSL method.

  11. Experimental study and simulation of airflow in solar chimneys

    Energy Technology Data Exchange (ETDEWEB)

    Saifi, Nadia; Dokkar, Boubekeur; Negrou, Belkhir; Settou, Noureddine [Laboratory for Bioressources Saharan Preservation and Enhancement, University of Kasdi Merbah (Algeria)], e-mail: saifi.nadia2009@gmail.com

    2011-07-01

    With the depletion of traditional energies, new technologies are arising that use renewable energies. The aim of this paper is to present a study of airflow in solar chimneys. Mathematical simulation and experiments were carried out on solar chimneys with different geometries. It was found that the width of the channel and the angle of inclination of the chimney influence the field speed. A case study was then carried out on a solar chimney in Ouargla Province, Algeria, to assess the impact of a chimney's inclination on its performance. The simulation was conducted using a finite volume method in Fluent 6.3.26 computer software. A good match between experimental and simulation results was found. This paper presented a study on airflow in solar chimney and demonstrated that simulations using Fluent and the finite element method were able to provide good results.

  12. Efficient airflow design for cleanrooms improves business bottom lines

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Tengfang

    2003-01-05

    Based on a review of airflow design factors and in-situ energy measurements in ISO Cleanliness Class-5 cleanrooms, this paper addresses the importance of energy efficiency in airflow design and opportunities of cost savings in cleanroom practices. The paper discusses design factors that can long lastingly affect cleanroom system performance, and demonstrates benefits of energy efficient cleanroom design from viewpoints of environmental control and business operations. The paper suggests that a high performance cleanroom should not only be effective in contamination control, but also be efficient in energy and environmental performance. The paper also suggests that energy efficient design practice stands to bring in immediate capital cost savings and operation cost savings, and should be regarded by management as a strategy to improve business bottom lines.

  13. Computational Investigation of Dynamic Glottal Aperture Effects on Respiratory Airflow

    Science.gov (United States)

    Xi, Jinxiang; Yan, Hong; Dong, Haibo

    2008-11-01

    The periodic movement of the glottal aperture (vocal folds) during tidal breathing has been long recognized as a factor in altering the airflow dynamics in the tracheobrnchial region. The potential influence from these altered flow structures on the transport and deposition of inhaled particles is not known. However, studies devoted to this dynamic physiological feature are scarce due to the complex anatomy in of the larynx and numerical challenges in simulating dynamic geometries. In this study, a high-fidelity immersed boundary solver is used to investigate this problem. A 3D human oral-larynx-lung model is firstly reconstructed from MRI data. The role of the vocal fold movement and associated airflow characteristics such as vortex shedding, Coanda effect etc. during inhalation and exhalation are then numerically studied.

  14. Liquid-core alginate hydrogel beads loaded with functional compounds of radish by-products by reverse spherification: Optimization by response surface methodology.

    Science.gov (United States)

    Tsai, Fu-Hsuan; Kitamura, Yutaka; Kokawa, Mito

    2017-03-01

    Liquid-core hydrogel beads (LHB) were formulated through reverse spherification, by sodium alginate and using calcium lactate (CL) to replace the common calcium source, calcium chloride. The effect of four independent variables: first gelation time (X1), CL concentration in first gelation (X2), secondary gelation time (X3), and CL concentration in secondary gelation (X4), on seven physical properties of LHB: diameter, hardness (Y1), loading efficiency (LE, Y2), release amount of total phenolic compounds (TP) in simulated gastric (Y3) and small intestinal (Y4) fluid, swelling capacity (Y5), and sphericity (Y6), were evaluated. Furthermore, a central composite design with response surface methodology was used for the optimization of LHB properties Y1-Y6, and the importance of the four independent variables to physical properties was analyzed. The diameter of LHB was in the range of 4.17-5.84mm. The optimal conditions of LHB formulation were first gelation time of 23.99min, 0.13M CL in the first gelation, secondary gelation time of 6.04min, and 0.058M CL in secondary gelation. The optimized formulation of LHB demonstrated 25.5N of hardness, 85.67% of LE and 27.38% of TP release in simulated gastric fluid with the small error-values (-2.47 to 2.21%).

  15. Improved cooling of electromagnetics by directed airflow

    Science.gov (United States)

    Fain, Adam Matthew

    The transformers in aircraft power conversion are often very heavy and represent a significant fuel or range penalty. Being thermally sized, improved cooling methods would allow downsizing and thereby reduced weight. Since the conductive paths in these metal "dense" devices are good, the controlling thermal resistance is typically the convective coefficient. The goal of this study was to optimize the convective air cooling across transformers by parametrically testing candidate shroud geometries to minimize average and hot spot surface temperatures with minimal fan power. A test set up was constructed that included a low velocity wind tunnel, fan, temperature and pressure sensors, DAQ system, and film heaters as well as the actual transformers. Experimental results from a low velocity wind tunnel were well predicted by CFD modeling, providing confidence in continued shroud development with only CFD or experimentally. Curved or bent types of shapes proved to be the most efficient shroud configurations in terms of maximizing heat transfer while reducing the energy requirement to achieve the desired level of cooling.

  16. Collecting aerosol in airflow with a magnetically stabilized fluidized bed

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    A magnetically stabilized fluidized bed (MSB) is a highly efficient filter that takes the advantage of both fluidized beds and fixed beds. This paper presents the research to collect aerosol in airflow with a MSB. The filtering model of MSB is established with its parameters including magnetic field intensity,gas superficial velocity, average grain-size, and bed height on thecollection efficiency of MSB. The model is verified by experiments.

  17. Model Experiments for the Determination of Airflow in Large Spaces

    DEFF Research Database (Denmark)

    Nielsen, Peter V.

    Model experiments are one of the methods used for the determination of airflow in large spaces. This paper will discuss the formation of the governing dimensionless numbers. It is shown that experiments with a reduced scale often will necessitate a fully developed turbulence level of the flow....... Details of the flow from supply openings are very important for the determination of room air distribution. It is in some cases possible to make a simplified supply opening for the model experiment....

  18. Realistic glottal motion and airflow rate during human breathing.

    Science.gov (United States)

    Scheinherr, Adam; Bailly, Lucie; Boiron, Olivier; Lagier, Aude; Legou, Thierry; Pichelin, Marine; Caillibotte, Georges; Giovanni, Antoine

    2015-09-01

    The glottal geometry is a key factor in the aerosol delivery efficiency for treatment of lung diseases. However, while glottal vibrations were extensively studied during human phonation, the realistic glottal motion during breathing is poorly understood. Therefore, most current studies assume an idealized steady glottis in the context of respiratory dynamics, and thus neglect the flow unsteadiness related to this motion. This is particularly important to assess the aerosol transport mechanisms in upper airways. This article presents a clinical study conducted on 20 volunteers, to examine the realistic glottal motion during several breathing tasks. Nasofibroscopy was used to investigate the glottal geometrical variations simultaneously with accurate airflow rate measurements. In total, 144 breathing sequences of 30s were recorded. Regarding the whole database, two cases of glottal time-variations were found: "static" or "dynamic" ones. Typically, the peak value of glottal area during slow breathing narrowed from 217 ± 54 mm(2) (mean ± STD) during inspiration, to 178 ± 35 mm(2) during expiration. Considering flow unsteadiness, it is shown that the harmonic approximation of the airflow rate underevaluates the inertial effects as compared to realistic patterns, especially at the onset of the breathing cycle. These measurements provide input data to conduct realistic numerical simulations of laryngeal airflow and particle deposition. Copyright © 2015 IPEM. Published by Elsevier Ltd. All rights reserved.

  19. Airflow Simulations around OA Intake Louver with Electronic Velocity Sensors

    Energy Technology Data Exchange (ETDEWEB)

    Han, Hwataik; Sullivan, Douglas P.; Fisk, William J.

    2009-04-01

    It is important to control outdoor airflow rates into HVAC systems in terms of energy conservation and healthy indoor environment. Technologies are being developed to measure outdoor air (OA) flow rates through OA intake louvers on a real time basis. The purpose of this paper is to investigate the airflow characteristics through an OA intake louver numerically in order to provide suggestions for sensor installations. Airflow patterns are simulated with and without electronic air velocity sensors within cylindrical probes installed between louver blades or at the downstream face of the louver. Numerical results show quite good agreements with experimental data, and provide insights regarding measurement system design. The simulations indicate that velocity profiles are more spatially uniform at the louver outlet relative to between louver blades, that pressure drops imposed by the sensor bars are smaller with sensor bars at the louver outlet, and that placement of the sensor bars between louver blades substantially increases air velocities inside the louver. These findings suggest there is an advantage to placing the sensor bars at the louver outlet face.

  20. The aligned nuclear targets for investigation of time reversal invariance violation: thermal heating and optimization of target dimension

    CERN Document Server

    Beda, A G

    2007-01-01

    The thermal heating of aligned nuclear targets of HIO_3, LiIO_3 ans Sb target materials under neutron irradiation at JSNS is considered. It is shown that presently the targets of large volumes (several tens of cm^3) can be used in experiment. The optimal target dimensions are recommended for investigation with resonance neutrons. The use of proposed aligned targets at the new neutron spallation source JSNS (Japan) will make p[ossible to discover TRIV or decrease the present limit on the intensity of parity conserving time violating interaction by two-three order of magnitude.

  1. 逆向物流配送网络优化方法研究%Study on Optimization of Reverse Logistics Distribution Networks

    Institute of Scientific and Technical Information of China (English)

    王庆

    2014-01-01

    对逆向物流网络的原理和优化进行深入分析,从企业的效益及核心竞争力出发,结合逆向物流网络的特点,在比较归纳逆向物流一般模型的基础上,提出一种新的物流网络模式,并建立了线性规划模型,结合实际案例分析,对逆向物流网络规划模型的有效性进行验证,为企业解决相关实际问题提供参考。%In this paper, we analyzed in-depth the principle in the optimization of reverse logistics networks, then in connection with the characteristics of the networks and on the basis of a summary and comparison of the generic reverse logistics model, proposed a new logistics network model and the corresponding linear programming model, and at the end, through a case study, verified the effectiveness of the models proposed.

  2. 完全可逆轴流风机的设计与优化%Design and Optimization of Fully Reversible Axial-flow Fan

    Institute of Scientific and Technical Information of China (English)

    刘力源; 李志平

    2013-01-01

    Aiming at the problem of greater losses in the forward and reverse operating of reversible axial-flow fan S-blade and problem of efficiency difficult to significantly improved, this paper analyzed the advantage of combined cascade relative to the S-shaped blade, so the concept of adopting combined cascade to design and combine reversible fan blades was pointed out, and the method of adopting controllable vortex torsional law was used to design high-efficient axial-flow fan with single rotor. Furthermore, in order to explore the influence of the relative positions of front and rear blades in the design of reversible fan combined blades on the overall performance of fan, the layout exploration was carried out on the combined blade’s design based on different axial and circumferential positions. Meanwhile, 16 sets of different rotor models were established, which were calculated numerically and analyzed in detail. So the optimal solution of designing the layout of front and rear blades for reversible fan was obtained. Finanlly, the obtained performance of fully reversible fan met the requirements, the efficiency in positive and negative position is above 85%. Meanwhile, the completely symmetrical layout of front and rear blades had ensured the fan performance was completely reversible.%针对可逆轴流风机S型叶片正反向运行损失较大,效率难以大幅度提高的问题,本文分析了组合叶栅相对于S型叶片的优势,采用组合叶栅的构想设计组合叶片可逆风机;采用可控涡扭向规律的设计方法设计出高效轴流风机单转子;为了探索可逆风机组合叶片设计中前后排叶片的相对位置对风机总性能的影响,对组合叶片设计进行了基于不同轴向和周向位置的布局探索,共建立了16套不同的转子模型,并进行详细的数值计算和分析对比,得出了可逆风机组合叶片设计前后排叶片布局的最佳方案,最终得到的完全可逆风机的

  3. Optimization of the elution buffer and concentration method for detecting hepatitis E virus in swine liver using a nested reverse transcription-polymerase chain reaction and real-time reverse transcription-polymerase chain reaction.

    Science.gov (United States)

    Son, Na Ry; Seo, Dong Joo; Lee, Min Hwa; Seo, Sheungwoo; Wang, Xiaoyu; Lee, Bog-Hieu; Lee, Jeong-Su; Joo, In-Sun; Hwang, In-Gyun; Choi, Changsun

    2014-09-01

    The aim of this study was to develop an optimal technique for detecting hepatitis E virus (HEV) in swine livers. Here, three elution buffers and two concentration methods were compared with respect to enhancing recovery of HEV from swine liver samples. Real-time reverse transcription-polymerase chain reaction (RT-PCR) and nested RT-PCR were performed to detect HEV RNA. When phosphate-buffered saline (PBS, pH 7.4) was used to concentrate HEV in swine liver samples using ultrafiltration, real-time RT-PCR detected HEV in 6 of the 26 samples. When threonine buffer was used to concentrate HEV using polyethylene glycol (PEG) precipitation and ultrafiltration, real-time RT-PCR detected HEV in 1 and 3 of the 26 samples, respectively. When glycine buffer was used to concentrate HEV using ultrafiltration and PEG precipitation, real-time RT-PCR detected HEV in 1 and 3 samples of the 26 samples, respectively. When nested RT-PCR was used to detect HEV, all samples tested negative regardless of the type of elution buffer or concentration method used. Therefore, the combination of real-time RT-PCR and ultrafiltration with PBS buffer was the most sensitive and reliable method for detecting HEV in swine livers. Copyright © 2014 Elsevier B.V. All rights reserved.

  4. Reversed-phase dispersive liquid-liquid microextraction with multivariate optimization for sensitive HPLC determination of tyrosol and hydroxytyrosol in olive oil.

    Science.gov (United States)

    Hashemi, Payman; Nazari Serenjeh, Fariba; Ghiasvand, Ali Reza

    2011-01-01

    A reversed-phase dispersive liquid-liquid microextraction (RP-DLLME) method coupled to HPLC was developed for the extraction of hydroxytyrosol (HTy) and tyrosol (Ty) from virgin olive oil. In this first application of the RP-DLLME method to non-polar samples, the phenolic compounds were directly extracted into an aqueous micro-drop, which could be injected into a chromatography column without any further pretreatment. A glass test tube with lengthened conical bottom was fitted inside a centrifuge tube in this work for more efficient withdrawal of the sedimented phase with a microsyringe. The volumes of water and ethyl acetate, the pH of water and the centrifuge time as four effective parameters on the extraction were optimized by a central composite design (response surface) method. Five replicated analyses under the optimized conditions (i.e., 0.2 mL ethyl acetate as disperser and 100 µL water at pH 11 as the extraction solvent) resulted in recoveries of 104.3 and 97.6%, and relative standard deviations of 5.75 and 4.57 for HTy and Ty, respectively. The detection limit of the method (3σ) was 0.043 mg L(-1) for HTy and 0.032 mg L(-1) for Ty. The method was successfully applied to the determination of HTy and Ty in five olive oil samples.

  5. Reverse engineering of logic-based differential equation models using a mixed-integer dynamic optimization approach.

    Science.gov (United States)

    Henriques, David; Rocha, Miguel; Saez-Rodriguez, Julio; Banga, Julio R

    2015-09-15

    Systems biology models can be used to test new hypotheses formulated on the basis of previous knowledge or new experimental data, contradictory with a previously existing model. New hypotheses often come in the shape of a set of possible regulatory mechanisms. This search is usually not limited to finding a single regulation link, but rather a combination of links subject to great uncertainty or no information about the kinetic parameters. In this work, we combine a logic-based formalism, to describe all the possible regulatory structures for a given dynamic model of a pathway, with mixed-integer dynamic optimization (MIDO). This framework aims to simultaneously identify the regulatory structure (represented by binary parameters) and the real-valued parameters that are consistent with the available experimental data, resulting in a logic-based differential equation model. The alternative to this would be to perform real-valued parameter estimation for each possible model structure, which is not tractable for models of the size presented in this work. The performance of the method presented here is illustrated with several case studies: a synthetic pathway problem of signaling regulation, a two-component signal transduction pathway in bacterial homeostasis, and a signaling network in liver cancer cells. Supplementary data are available at Bioinformatics online. julio@iim.csic.es or saezrodriguez@ebi.ac.uk. © The Author 2015. Published by Oxford University Press.

  6. Reversal of rocuronium-induced neuromuscular blockade by sugammadex allows for optimization of neural monitoring of the recurrent laryngeal nerve.

    Science.gov (United States)

    Lu, I-Cheng; Wu, Che-Wei; Chang, Pi-Ying; Chen, Hsiu-Ya; Tseng, Kuang-Yi; Randolph, Gregory W; Cheng, Kuang-I; Chiang, Feng-Yu

    2016-04-01

    The use of neuromuscular blocking agent may effect intraoperative neuromonitoring (IONM) during thyroid surgery. An enhanced neuromuscular-blockade (NMB) recovery protocol was investigated in a porcine model and subsequently clinically applied during human thyroid neural monitoring surgery. Prospective animal and retrospective clinical study. In the animal experiment, 12 piglets were injected with rocuronium 0.6 mg/kg and randomly allocated to receive normal saline, sugammadex 2 mg/kg, or sugammadex 4 mg/kg to compare the recovery of laryngeal electromyography (EMG). In a subsequent clinical application study, 50 patients who underwent thyroidectomy with IONM followed an enhanced NMB recovery protocol-rocuronium 0.6 mg/kg at anesthesia induction and sugammadex 2 mg/kg at the operation start. The train-of-four (TOF) ratio was used for continuous quantitative monitoring of neuromuscular transmission. In our porcine model, it took 49 ± 15, 13.2 ± 5.6, and 4.2 ± 1.5 minutes for the 80% recovery of laryngeal EMG after injection of saline, sugammadex 2 mg/kg, and sugammadex 4 mg/kg, respectively. In subsequent clinical human application, the TOF ratio recovered from 0 to >0.9 within 5 minutes after administration of sugammadex 2 mg/kg at the operation start. All patients had positive and high EMG amplitude at the early stage of the operation, and intubation was without difficulty in 96% of patients. Both porcine modeling and clinical human application demonstrated that sugammadex 2 mg/kg allows effective and rapid restoration of neuromuscular function suppressed by rocuronium. Implementation of this enhanced NMB recovery protocol assures optimal conditions for tracheal intubation as well as IONM in thyroid surgery. NA. © 2016 The American Laryngological, Rhinological and Otological Society, Inc.

  7. Reversible Logic Circuit Synthesis

    CERN Document Server

    Shende, V V; Markov, I L; Prasad, A K; Hayes, John P.; Markov, Igor L.; Prasad, Aditya K.; Shende, Vivek V.

    2002-01-01

    Reversible, or information-lossless, circuits have applications in digital signal processing, communication, computer graphics and cryptography. They are also a fundamental requirement for quantum computation. We investigate the synthesis of reversible circuits that employ a minimum number of gates and contain no redundant input-output line-pairs (temporary storage channels). We propose new constructions for reversible circuits composed of NOT, Controlled-NOT, and TOFFOLI gates (the CNT gate library) based on permutation theory. A new algorithm is given to synthesize optimal reversible circuits using an arbitrary gate library. We also describe much faster heuristic algorithms. We also pursue applications of the proposed techniques to the synthesis of quantum circuits.

  8. Investigation of non-uniform airflow signal oscillation during high frequency chest compression

    OpenAIRE

    Lee Jongwon; Lee Yong W; Warwick Warren J; Sohn Kiwon; Holte James E

    2005-01-01

    Abstract Background High frequency chest compression (HFCC) is a useful and popular therapy for clearing bronchial airways of excessive or thicker mucus. Our observation of respiratory airflow of a subject during use of HFCC showed the airflow oscillation by HFCC was strongly influenced by the nonlinearity of the respiratory system. We used a computational model-based approach to analyse the respiratory airflow during use of HFCC. Methods The computational model, which is based on previous ph...

  9. Experimental characterization of airflow, heat and mass transfer in a cold room filled with food products

    OpenAIRE

    Duret, S.; Hoang, H. -M.; Flick, Denis; Laguerre, O.

    2014-01-01

    Temperature and moisture heterogeneity, with non-uniform airflow in cold rooms was observed in several studies. This heterogeneity can lead to a deterioration of food quality and safety. Heat and mass transfer in cold rooms is a complex phenomenon because of the presence of the product (airflow modification, heat of respiration.) and the coupling between heat transfer and airflow. Temperature, velocity, humidity and heat transfer coefficient measurements were carried out in a ventilated cold ...

  10. Effect of airflow velocity on moisture exchange at surfaces of building materials

    DEFF Research Database (Denmark)

    Mortensen, Lone Hedegaard; Rode, Carsten; Peuhkuri, Ruut Hannele

    2006-01-01

    The moisture transfer between air and construction are affected of the boundary layer conditions close to the surface, which is influenced by the airflow patterns in the room. Therefore an investigation of the relation be-tween the surface resistance and the airflow velocity above a material sample...... resistances decrease for increasing airflow velocity above the boundary layer of the material surface. The measured resistances are somewhat smaller than the ones esti-mated by use of the Lewis relation....

  11. Contamination control in HVAC systems for aseptic processing area. Part I: Case study of the airflow velocity in a unidirectional airflow workstation with computational fluid dynamics.

    Science.gov (United States)

    Ogawa, M

    2000-01-01

    A unidirectional airflow workstation for processing a sterile pharmaceutical product is required to be "Grade A," according to EU-GMP and WHO-GMP. These regulations have employed the wording of "laminar airflow" for unidirectional airflow, with an unclear definition given. This seems to have allowed many reports to describe discussion of airflow velocity only. The guidance values as to the velocity are expressed in various words of 90 ft/min, 0.45 m/sec, 0.3 m/sec, +/- 20%, or "homogeneous air speed." It has been also little clarified how variation in airflow velocity gives influences on contamination control of a workstation working with varying key characteristics, such as ceiling height, internal heat load, internal particle generation, etc. The present author has revealed following points from a case study using Computational Fluid Dynamics: the airflow characteristic in Grade A area shows no significant changes with varying the velocity of supplied airflow, and the particles generated from the operator will be exhausted outside Grade A area without contamination.

  12. Optimism

    Science.gov (United States)

    Carver, Charles S.; Scheier, Michael F.; Segerstrom, Suzanne C.

    2010-01-01

    Optimism is an individual difference variable that reflects the extent to which people hold generalized favorable expectancies for their future. Higher levels of optimism have been related prospectively to better subjective well-being in times of adversity or difficulty (i.e., controlling for previous well-being). Consistent with such findings, optimism has been linked to higher levels of engagement coping and lower levels of avoidance, or disengagement, coping. There is evidence that optimism is associated with taking proactive steps to protect one's health, whereas pessimism is associated with health-damaging behaviors. Consistent with such findings, optimism is also related to indicators of better physical health. The energetic, task-focused approach that optimists take to goals also relates to benefits in the socioeconomic world. Some evidence suggests that optimism relates to more persistence in educational efforts and to higher later income. Optimists also appear to fare better than pessimists in relationships. Although there are instances in which optimism fails to convey an advantage, and instances in which it may convey a disadvantage, those instances are relatively rare. In sum, the behavioral patterns of optimists appear to provide models of living for others to learn from. PMID:20170998

  13. Real-time visualization and analysis of airflow field by use of digital holography

    Science.gov (United States)

    Di, Jianglei; Wu, Bingjing; Chen, Xin; Liu, Junjiang; Wang, Jun; Zhao, Jianlin

    2013-04-01

    The measurement and analysis of airflow field is very important in fluid dynamics. For airflow, smoke particles can be added to visually observe the turbulence phenomena by particle tracking technology, but the effect of smoke particles to follow the high speed airflow will reduce the measurement accuracy. In recent years, with the advantage of non-contact, nondestructive, fast and full-field measurement, digital holography has been widely applied in many fields, such as deformation and vibration analysis, particle characterization, refractive index measurement, and so on. In this paper, we present a method to measure the airflow field by use of digital holography. A small wind tunnel model made of acrylic glass is built to control the velocity and direction of airflow. Different shapes of samples such as aircraft wing and cylinder are placed in the wind tunnel model to produce different forms of flow field. With a Mach-Zehnder interferometer setup, a series of digital holograms carrying the information of airflow filed distributions in different states are recorded by CCD camera and corresponding holographic images are numerically reconstructed from the holograms by computer. Then we can conveniently obtain the velocity or pressure information of the airflow deduced from the quantitative phase information of holographic images and visually display the airflow filed and its evolution in the form of a movie. The theory and experiment results show that digital holography is a robust and feasible approach for real-time visualization and analysis of airflow field.

  14. Activity patterns elicited by airflow in the olfactory bulb and their possible functions.

    Science.gov (United States)

    Wu, Ruiqi; Liu, Yue; Wang, Li; Li, Bo; Xu, Fuqiang

    2017-10-02

    Olfactory sensory neurons (OSNs) can sense both odorants and airflows. In the olfactory bulb (OB), the coding of odor information is well studied, but the coding of mechanical stimulation is rarely investigated. Unlike odor sensing, the functions of airflow sensing of OSNs are also largely unknown. Here, the activity patterns elicited by mechanical airflow in male rat OBs were mapped using fMRI and correlated with local field potential recordings. In an attempt to reveal possible functions of airflow sensing, the relationship between airflow patterns and physiological parameters was also examined. We found that: a) the activity pattern in the OB evoked by airflow in the nasal cavity was more broadly distributed, compared with those evoked by odors; b) the pattern intensity increases with total airflow, while the pattern topography is rather similar; and c) the heart rate, spontaneous respiratory rate, and EEG power in β-band were reduced under regular mechanical airflow, compared with no airflow through the nasal cavity. The mapping results provide evidence that the signals elicited by mechanical airflow in OSNs are transmitted to the OB, and that the OB has the potential to code and process mechanical information. Our functional data indicate that airflow rhythm in the olfactory system is able to regulate the physiological and brain states, providing an explanation for the effects of breath controlling in meditation, yoga, and Taoism practices.Significant statementThe studies about presentation of odor information in the olfactory bulb is comprehensive, while that of breathing features is rare. Here we investigated the global activity patterns in the rat olfactory bulb elicited by airflow in the nasal cavity using BOLD-fMRI for the first time and found that the activity pattern elicited by airflow is broadly distributed, with increasing pattern intensity and similar topography under increasing total airflow. Further, heart rate, spontaneous respiratory rate in

  15. Estimation of Airflow in Livestock Buildings using Image Analysis

    DEFF Research Database (Denmark)

    Larsen, Rasmus

    1996-01-01

    In order to evaluate a given ventilation system in a livestock building and its sensitivity to wind, presence of heat sources (e.g. livestock) etc. it is of interest to estimate flow vector fields corresponding to the airflow. By introducing particles (e.g. smoke) into the air inlets of a model...... on the image sequence. After which the local estimates are integrated to smooth flow fields using a model that incorporates spatial smoothness. The algorithms are illustrated using a scale model of a pigs sty under isothermic conditions. It should be noted that this is an non-invasive technique (laser...

  16. EFFECT OF AIRFLOW AND HEAT INPUT RATES ON DUCT EFFICIENCY.

    Energy Technology Data Exchange (ETDEWEB)

    ANDREWS,J.W.

    2003-05-28

    Reducing the airflow and heat input rates of a furnace that is connected to a duct system in thermal contact with unconditioned spaces can significantly reduce thermal distribution efficiency. This is a straightforward theoretical calculation based on the increased residence time of the air in the duct at the lower flow rate, which results in greater conduction losses. Experimental tests in an instrumented residential-size duct system have confirmed this prediction. Results are compared with the heat-loss algorithm in ASHRAE Standid 152P. The paper concludes with a discussion of possible remedies for this loss of efficiency in existing systems and optional design strategies in new construction.

  17. CFD modeling of pharmaceutical isolators with experimental verification of airflow.

    Science.gov (United States)

    Nayan, N; Akay, H U; Walsh, M R; Bell, W V; Troyer, G L; Dukes, R E; Mohan, P

    2007-01-01

    Computational fluid dynamics (CFD) models have been developed to predict the airflow in a transfer isolator using a commercial CFD code. In order to assess the ability of the CFD approach in predicting the flow inside an isolator, hot wire anemometry measurements and a novel experimental flow visualization technique consisting of helium-filled glycerin bubbles were used. The results obtained have been shown to agree well with the experiments and show that CFD can be used to model barrier systems and isolators with practical fidelity. This indicates that CFD can and should be used to support the design, testing, and operation of barrier systems and isolators.

  18. Airflow characteristics in the occupied zone of ventilated spaces

    DEFF Research Database (Denmark)

    Hanzawa, H.; Melikov, Arsen Krikor; Fanger, Povl Ole

    1987-01-01

    raft is one of the most common causes of complaint in ventilated or air-conditioned spaces. Therefore, knowing the turbulent airflow in these spaces and the impact of this flow on the sensation of draft is very important. The characteristics of turbulent flow (turbulence intensity, length scales...... of turbulence, turbulence kinetic energy, etc. ) were investigated in 20 typically ventilated spaces. Relationships between these characteristics and the mean velocity were found. The turbulence energy spectra are similar to those in a fully developed turbulent flow. The spectra reveal the major contribution...

  19. Airflow Characteristics at the Breathing Zone of a Seated Person

    DEFF Research Database (Denmark)

    Bolashikov, Zhecho Dimitrov; Nagano, Hideaki; Melikov, Arsen Krikor;

    2011-01-01

    . Passive method for control over the airflow characteristics at the breathing zone to increase the amount of clean air in inhalation consisted of a rectangular board (0.63 m x 0.36 m) placed below the table and pressed against the abdominal. It acted as a barrier reducing the convection flow upcoming from...... the lower body. The resultant velocity field at the breathing zone was measured with Particle Image Velocimetry: a dual cavity laser (λ = 532 nm) and two CCD cameras with 35 and 60 mm lenses. Seeding consisting of glycerol droplets (d = 2-3 μm) was added to the total volume supply. The blocking...

  20. Optimization

    CERN Document Server

    Pearce, Charles

    2009-01-01

    Focuses on mathematical structure, and on real-world applications. This book includes developments in several optimization-related topics such as decision theory, linear programming, turnpike theory, duality theory, convex analysis, and queuing theory.

  1. Reverse airflow in certain chest drains may be misinterpreted as prolonged air leakage

    DEFF Research Database (Denmark)

    Stouby, Anna; Neckelmann, Kirsten; Licht, Peter B

    2011-01-01

    Prolonged air leakage is common after lung resection. We observed that during deep inspiration some patients were able to empty the water-seal of commercial chest drainage systems and retract air back into the chest tube, which subsequently escaped during the following expiration, mimicking "true...

  2. Accurate prediction of HIV-1 drug response from the reverse transcriptase and protease amino acid sequences using sparse models created by convex optimization.

    Science.gov (United States)

    Rabinowitz, Matthew; Myers, Lance; Banjevic, Milena; Chan, Albert; Sweetkind-Singer, Joshua; Haberer, Jessica; McCann, Kelly; Wolkowicz, Roland

    2006-03-01

    Genotype-phenotype modeling problems are often overcomplete, or ill-posed, since the number of potential predictors-genes, proteins, mutations and their interactions-is large relative to the number of measured outcomes. Such datasets can still be used to train sparse parameter models that generalize accurately, by exerting a principle similar to Occam's Razor: When many possible theories can explain the observations, the most simple is most likely to be correct. We apply this philosophy to modeling the drug response of Type-1 Human Immunodeficiency Virus (HIV-1). Owing to the decreasing expense of genetic sequencing relative to in vitro phenotype testing, a statistical model that reliably predicts viral drug response from genetic data is an important tool in the selection of antiretroviral therapy (ART). The optimization techniques described will have application to many genotype-phenotype modeling problems for the purpose of enhancing clinical decisions. We describe two regression techniques for predicting viral phenotype in response to ART from genetic sequence data. Both techniques employ convex optimization for the continuous subset selection of a sparse set of model parameters. The first technique, the least absolute shrinkage and selection operator, uses the l(1) norm loss function to create a sparse linear model; the second, the support vector machine with radial basis kernel functions, uses the epsilon-insensitive loss function to create a sparse non-linear model. The techniques are applied to predict the response of the HIV-1 virus to 10 reverse transcriptase inhibitor and 7 protease inhibitor drugs. The genetic data are derived from the HIV coding sequences for the reverse transcriptase and protease enzymes. When tested by cross-validation with actual laboratory measurements, these models predict drug response phenotype more accurately than models previously discussed in the literature, and other canonical techniques described here. Key features of the

  3. Investigation of non-uniform airflow signal oscillation during high frequency chest compression

    Directory of Open Access Journals (Sweden)

    Lee Jongwon

    2005-05-01

    Full Text Available Abstract Background High frequency chest compression (HFCC is a useful and popular therapy for clearing bronchial airways of excessive or thicker mucus. Our observation of respiratory airflow of a subject during use of HFCC showed the airflow oscillation by HFCC was strongly influenced by the nonlinearity of the respiratory system. We used a computational model-based approach to analyse the respiratory airflow during use of HFCC. Methods The computational model, which is based on previous physiological studies and represented by an electrical circuit analogue, was used for simulation of in vivo protocol that shows the nonlinearity of the respiratory system. Besides, airflow was measured during use of HFCC. We compared the simulation results to either the measured data or the previous research, to understand and explain the observations. Results and discussion We could observe two important phenomena during respiration pertaining to the airflow signal oscillation generated by HFCC. The amplitudes of HFCC airflow signals varied depending on spontaneous airflow signals. We used the simulation results to investigate how the nonlinearity of airway resistance, lung capacitance, and inertance of air characterized the respiratory airflow. The simulation results indicated that lung capacitance or the inertance of air is also not a factor in the non-uniformity of HFCC airflow signals. Although not perfect, our circuit analogue model allows us to effectively simulate the nonlinear characteristics of the respiratory system. Conclusion We found that the amplitudes of HFCC airflow signals behave as a function of spontaneous airflow signals. This is due to the nonlinearity of the respiratory system, particularly variations in airway resistance.

  4. Current status of nuclear medicine in chronic airflow limitation

    Energy Technology Data Exchange (ETDEWEB)

    Clarke, S.W.; Agnew, J.E.

    1987-06-01

    Radionuclide imaging, quite apart from its role in the diagnosis of pulmonary embolism, offers information about the distribution of ventilatory and perfusion abnormalities within the lung. The extent of ventilatory abnormality seen can be related to the severity of airways obstruction as assessed spirometrically, whilst abnormalities in the matching of perfusion to ventilation can be related to the severity of hypoxaemia in patients with chronic airflow limitation. Clearance of mucus from the lungs of patients with chronic mucus hypersection may be assessed by following the clearance rate of insoluble radioaerosol particles; by such means the relative contributions of mucociliary transport and of cough to the overall clearance can be observed. Clearance is often severely impaired in patients with airways obstruction; the radioaerosol technique can be used to determine the effects of drug or physiotherapy treatment. Chronic airflow limitation leading to hypoxaemia can be associated with pulmonary artery hypertension and right ventricular hypertrophy - this may be investigated noninvasively by a radionuclide test of right ventricular ejection fraction.

  5. β-catenin, Twist and Snail: Transcriptional regulation of EMT in smokers and COPD, and relation to airflow obstruction.

    Science.gov (United States)

    Mahmood, Malik Quasir; Walters, Eugene Haydn; Shukla, Shakti D; Weston, Steve; Muller, Hans Konrad; Ward, Chris; Sohal, Sukhwinder Singh

    2017-09-07

    COPD is characterised by poorly reversible airflow obstruction usually due to cigarette smoking. The transcription factor clusters of β-catenin/Snail1/Twist has been implicated in the process of epithelial mesenchymal transition (EMT), an intermediate between smoking and airway fibrosis, and indeed lung cancer. We have investigated expression of these transcription factors and their "cellular localization" in bronchoscopic airway biopsies from patients with COPD, and in smoking and non-smoking controls. An immune-histochemical study compared cellular protein expression of β-catenin, Snail1 and Twist, in these subject groups in 3 large airways compartment: epithelium (basal region), reticular basement membrane (Rbm) and underlying lamina propria (LP). β-catenin and Snail1 expression was generally high in all subjects throughout the airway wall with marked cytoplasmic to nuclear shift in COPD (P Snail1 expression, and to lesser extent of Twist, was related to airflow obstruction and to expression of a canonical EMT biomarker (S100A4). The β-catenin-Snail1-Twist transcription factor cluster is up-regulated and nuclear translocated in smokers and COPD, and their expression is closely related to both EMT activity and airway obstruction.

  6. 最适化逆向运筹服务产能配置%Optimizing Service Capacity Allocation in Reverse Logistics Chain

    Institute of Scientific and Technical Information of China (English)

    廖明癸

    2012-01-01

    逆向运筹的规划与管理对产业的营运绩效有着相当显著的重要性.文章旨在建立服务策略与成本分析数学模式,在最小化整体服务成本的考虑下,设计最适化区域策略伙伴的选定与服务产能配置,由于前后不同等级服务点的选定会彼此牵制服务成本,影响最终整体成本.因此,以非线性规划求解服务策略分析问题,范例说明在设定服务点选择与无产能限制条件下,最大与最小整体服务成本为5.54%及3.11%销售额,相差近78.1%,约2.43%销售额,严重影响公司最后营运绩效与公司竞争力.后续研究可依本文数学模式,加入不同产业特性与限制条件,或增加环境冲击与客户满意度成本考虑,找出最适化不同服务等级服务点选定与产能配置.%The strategy and management of reverse logistics significantly affects business performance. A mathematical model is presented here to optimize service strategy for third-party logistics partners (3PLs) selection and capacity allocation in balance of the consideration of customer satisfaction and total warranty claims. This service strategy analysis is a nonlinear programming problem owing to each service level warranty claims will depend on previous and following service level arrangement. Example shows the gap of warranty claim may up to 2. 43% of revenues, 78. 1% difference between optimal solution 3. 11% and worst scenario 5. 54% of revenues. It seriously impacts overall business performance and company competitiveness. To add extra service cost element into the presented mathematical model here, environment impact or customer satisfaction, is interesting for research following based on different industrial constraints, trying to optimize 3PLs location and capacity allocation.

  7. Harvesting energy from airflow with a michromachined piezoelectric harvester inside a Helmholtz resonator

    NARCIS (Netherlands)

    Matova, S.P.; Elfrink, R.; Vullers, R.J.M.; Schaijk, R. van

    2011-01-01

    In this paper we report an airflow energy harvester that combines a piezoelectric energy harvester with a Helmholtz resonator. The resonator converts airflow energy to air oscillations which in turn are converted into electrical energy by a piezoelectric harvester. Two Helmholtz resonators with adju

  8. Effect of airflow velocity on moisture exchange at surfaces of building materials

    DEFF Research Database (Denmark)

    Mortensen, Lone Hedegaard; Rode, Carsten; Peuhkuri, Ruut Hannele

    2006-01-01

    The moisture transfer between air and construction are affected of the boundary layer conditions close to the surface, which is influenced by the airflow patterns in the room. Therefore an investigation of the relation be-tween the surface resistance and the airflow velocity above a material samp...

  9. Prediction of Indoor Airflow Patterns in Livestock Buildings Ventilated through a Diffuse Ceiling

    DEFF Research Database (Denmark)

    Jacobsen, L.; Nielsen, Peter Vilhelm; Morsing, S.

    2004-01-01

    The airflow conditions in an experimental pig housing unit are examined both experimentally and numerically (simulation) with particular focus on the airflow conditions in the occupational zone of the animals. Two heating setups are used, and the temperature is measured in a horizontal profile at...

  10. 42 CFR 84.1149 - Airflow resistance tests; all dust, fume, and mist respirators; minimum requirements.

    Science.gov (United States)

    2010-10-01

    ... 42 Public Health 1 2010-10-01 2010-10-01 false Airflow resistance tests; all dust, fume, and mist... RESPIRATORY PROTECTIVE DEVICES Dust, Fume, and Mist; Pesticide; Paint Spray; Powered Air-Purifying High Efficiency Respirators and Combination Gas Masks § 84.1149 Airflow resistance tests; all dust, fume, and...

  11. The Measurement of Airflow Using Singing Helmet That Allows Free Movement of the Jaw.

    Science.gov (United States)

    Jiang, Jack J; Hanna, Rewais B; Willey, Malachi V; Rieves, Adam

    2016-11-01

    Airflow measurement is a useful method of evaluating laryngeal physiology. We introduce a noninvasive device that measures airflow without restricting jaw movement or requiring phonation into a mouthpiece, thus facilitating measurement during singing and connected speech. Validation and human subject trials were conducted. Airflow measurements were obtained from 16 male and 16 female subjects during singing, speech, and constant vowel production tasks. A similar helmet was designed by Stevens and Mead in 1968. The new device validity was evaluated by comparing the measured volume of air to a known volume of administered air using a calibration syringe. Subjects were asked to voice sustained vowels at low, medium, and high vocal intensity, read two sentences at a conversational volume, and perform different singing exercises while airflow was recorded. The device accurately and reliably measured airflow with mean airflow values falling within previously published ranges. There was an experimentally determined response time of 0.173 ± 0.014 seconds. Subjects were able to comfortably perform speech and singing exercises. Male subjects had higher airflow for all sustained vowels (P speech while allowing for free movement of the jaw. This device provides a more natural environment to measure airflow that could be used to help evaluate laryngeal function and aid in singing training. Copyright © 2016 The Voice Foundation. Published by Elsevier Inc. All rights reserved.

  12. Advanced airflow distribution methods for reduction of personal exposure to indoor pollutants

    DEFF Research Database (Denmark)

    Cao, Guangyu; Kosonen, Risto; Melikov, Arsen

    2016-01-01

    The main objective of this study is to recognize possible airflow distribution methods to protect the occupants from exposure to various indoor pollutants. The fact of the increasing exposure of occupants to various indoor pollutants shows that there is an urgent need to develop advanced airflow ...... distribution methods to reduce indoor exposure to various indoor pollutants. This article presents some of the latest development of advanced airflow distribution methods to reduce indoor exposure in various types of buildings.......The main objective of this study is to recognize possible airflow distribution methods to protect the occupants from exposure to various indoor pollutants. The fact of the increasing exposure of occupants to various indoor pollutants shows that there is an urgent need to develop advanced airflow...

  13. Volume Diffuse Dielectric Barrier Discharge Plasma Produced by Nanosecond High Voltage Pulse in Airflow

    Institute of Scientific and Technical Information of China (English)

    QI Haicheng; GAO Wei; FAN Zhihui; LIU Yidi; REN Chunsheng

    2016-01-01

    Volume diffuse dielectric barrier discharge (DBD) plasma is produced in subsonic airflow by nanosecond high-voltage pulse power supply with a plate-to-plate discharge cell at 6 mm air gap length.The discharge images,optical emission spectra (OES),the applied voltage and current waveforms of the discharge at the changed airflow rates are obtained.When airflow rate is increased,the transition of the discharge mode and the variations of discharge intensity,breakdown characteristics and the temperature of the discharge plasma are investigated.The results show that the discharge becomes more diffuse,discharge intensity is decreased accompanied by the increased breakdown voltage and time lag,and the temperature of the discharge plasma reduces when airflow of small vclocity is introduced into the discharge gap.These phenomena are because that the airflow changes the spatial distribution of the heat and the space charge in the discharge gap.

  14. Volume Diffuse Dielectric Barrier Discharge Plasma Produced by Nanosecond High Voltage Pulse in Airflow

    Science.gov (United States)

    Qi, Haicheng; Gao, Wei; Fan, Zhihui; Liu, Yidi; Ren, Chunsheng

    2016-05-01

    Volume diffuse dielectric barrier discharge (DBD) plasma is produced in subsonic airflow by nanosecond high-voltage pulse power supply with a plate-to-plate discharge cell at 6 mm air gap length. The discharge images, optical emission spectra (OES), the applied voltage and current waveforms of the discharge at the changed airflow rates are obtained. When airflow rate is increased, the transition of the discharge mode and the variations of discharge intensity, breakdown characteristics and the temperature of the discharge plasma are investigated. The results show that the discharge becomes more diffuse, discharge intensity is decreased accompanied by the increased breakdown voltage and time lag, and the temperature of the discharge plasma reduces when airflow of small velocity is introduced into the discharge gap. These phenomena are because that the airflow changes the spatial distribution of the heat and the space charge in the discharge gap. supported by National Natural Science Foundation of China (No. 51437002)

  15. 往复流散热方式的锂离子电池热管理%Thermal Management of Lithium-ion Battery with Reciprocating Air-flow Cooling Mode

    Institute of Scientific and Technical Information of China (English)

    梁波; 欧阳陈志; 刘燕平; 毛聪; 唐思绮; 江清柏

    2014-01-01

    For solving the problem of the temperature unevenness among individual cells in battery module affecting service performance and lifespan of battery, a reciprocating air-flow cooling mode is adopted in this paper, with which the direction of cooling air flow is reversed periodically to reduce the temperature gradient in battery a-long air-flow direction in conventional cooling mode with unidirectional air flow. The results show that with recipro-cating flow cooling mode, the temperature evenness of battery increases by 12. 1% and 62. 4% respectively under 1C and 13. 33 C discharge current rates, so the service performance and safety of battery greatly improved with its service life extended. In addition, an optimization is also carried out on three parameters affecting heat dissipation performance, i. e. the velocity and temperature of air flow at inlet and reversal frequency, with the law of their in-fluence on the highest temperature and temperature difference of battery revealed.%为解决电池模块内部单体电池间的温度不均匀性而影响电池的使用性能和寿命的问题,本文中采用了一种往复流冷却方式,使冷却空气流动方向周期性逆转,以降低单向流空气冷却方式时单体电池沿空气流方向的温度梯度。结果表明,采用往复流冷却方式后,在1C和13.33C放电倍率下,电池温度均匀性分别提高了12.1%和62.4%,电池模块的使用性能和安全性得到改善,电池使用寿命得以提高。同时,文中还利用计算流体动力学虚拟试验与正交优化相结合,对影响往复流散热性能的往复流入口的速度与温度和往复周期3个参数进行了优化,并揭示了它们对电池最高温度和温差的影响规律。

  16. Autonomous Sensors Powered by Energy Harvesting from von Karman Vortices in Airflow.

    Science.gov (United States)

    Demori, Marco; Ferrari, Marco; Bonzanini, Arianna; Poesio, Pietro; Ferrari, Vittorio

    2017-09-13

    In this paper an energy harvesting system based on a piezoelectric converter to extract energy from airflow and use it to power battery-less sensors is presented. The converter is embedded as a part of a flexure beam that is put into vibrations by von Karman vortices detached from a bluff body placed upstream. The vortex street has been investigated by Computational Fluid Dynamics (CFD) simulations, aiming at assessing the vortex shedding frequency as a function of the flow velocity. From the simulation results the preferred positioning of the beam behind the bluff body has been derived. In the experimental characterization the electrical output from the converter has been measured for different flow velocities and beam orientations. Highest conversion effectiveness is obtained by an optimal orientation of the beam, to exploit the maximum forcing, and for flow velocities where the repetition frequency of the vortices allows to excite the beam resonant frequency at its first flexural mode. The possibility to power battery-less sensors and make them autonomous has been shown by developing an energy management and signal conditioning electronic circuit plus two sensors for measuring temperature and flow velocity and transmitting their values over a RF signal. A harvested power of about 650 μW with retransmission intervals below 2 min have been obtained for the optimal flow velocity of 4 m/s.

  17. Autonomous Sensors Powered by Energy Harvesting from von Karman Vortices in Airflow

    Directory of Open Access Journals (Sweden)

    Marco Demori

    2017-09-01

    Full Text Available In this paper an energy harvesting system based on a piezoelectric converter to extract energy from airflow and use it to power battery-less sensors is presented. The converter is embedded as a part of a flexure beam that is put into vibrations by von Karman vortices detached from a bluff body placed upstream. The vortex street has been investigated by Computational Fluid Dynamics (CFD simulations, aiming at assessing the vortex shedding frequency as a function of the flow velocity. From the simulation results the preferred positioning of the beam behind the bluff body has been derived. In the experimental characterization the electrical output from the converter has been measured for different flow velocities and beam orientations. Highest conversion effectiveness is obtained by an optimal orientation of the beam, to exploit the maximum forcing, and for flow velocities where the repetition frequency of the vortices allows to excite the beam resonant frequency at its first flexural mode. The possibility to power battery-less sensors and make them autonomous has been shown by developing an energy management and signal conditioning electronic circuit plus two sensors for measuring temperature and flow velocity and transmitting their values over a RF signal. A harvested power of about 650 μW with retransmission intervals below 2 min have been obtained for the optimal flow velocity of 4 m/s.

  18. Airflow Characteristics At The Breathing Zone of a Seated Person

    DEFF Research Database (Denmark)

    Bolashikov, Zhecho Dimitrov; Melikov, Arsen Krikor; Velte, Clara Marika

    2011-01-01

    A workstation with Personalized Ventilation (PV) unit and a thermal manikin with realistic body and temperature distribution were set in a test room (4.70 m x 1.62 m x 2.6 m). Airflow at 15 L/s was supplied from a ceiling diffuser to ventilate the room and keep the temperature at 26 oC. The PV co...... measured near the mouth was 0.1 m/s, when the boxes were installed but not working. When the two slots supplied equal amount of air, the measured absolute mean velocity increased with increasing the supplied air with a maximum of 0.35 m/s at 10 L/s....

  19. Effect of airflow on biodrying of gardening wastes in reactors

    Institute of Scientific and Technical Information of China (English)

    F.J.Colomer-Mendoza; L.Herrera-Prats; F.Robles-Martínez; A.Gallardo-Izquierdo; A.B.Pi(n)a-Guzmán

    2013-01-01

    Biodrying consists of reducing moisture by using the heat from aerobic bio-degradation.The parameters that control the process are:aeration,temperature during the process,initial moisture of biowaste,and temperature and relative humidity of the input air.Lawn mowing and garden waste from the gardens of the University Jaume I,Castellón (Spain) were used as a substrate.Biodrying was performed in 10 reactors with known air volumes from 0.88 to 6.42 L/(min·kg dry weight).To promote aeration,5 of the reactors had 15% of a bulking agent added.The experiment lasted 20 days.After the experiments it was found that the bulking agent led to greater weight loss.However,the increased airflow rate was not linearly proportional to the weight loss.

  20. Mechanics of airflow in the human nasal airways.

    Science.gov (United States)

    Doorly, D J; Taylor, D J; Schroter, R C

    2008-11-30

    The mechanics of airflow in the human nasal airways is reviewed, drawing on the findings of experimental and computational model studies. Modelling inevitably requires simplifications and assumptions, particularly given the complexity of the nasal airways. The processes entailed in modelling the nasal airways (from defining the model, to its production and, finally, validating the results) is critically examined, both for physical models and for computational simulations. Uncertainty still surrounds the appropriateness of the various assumptions made in modelling, particularly with regard to the nature of flow. New results are presented in which high-speed particle image velocimetry (PIV) and direct numerical simulation are applied to investigate the development of flow instability in the nasal cavity. These illustrate some of the improved capabilities afforded by technological developments for future model studies. The need for further improvements in characterising airway geometry and flow together with promising new methods are briefly discussed.

  1. Effect of airflow on biodrying of gardening wastes in reactors.

    Science.gov (United States)

    Colomer-Mendoza, F J; Herrera-Prats, L; Robles-Martínez, F; Gallardo-Izquierdo, A; Piña-Guzmán, A B

    2013-05-01

    Biodrying consists of reducing moisture by using the heat from aerobic bio-degradation. The parameters that control the process are: aeration, temperature during the process, initial moisture of biowaste, and temperature and relative humidity of the input air. Lawn mowing and garden waste from the gardens of the University Jaume I, Castellón (Spain) were used as a substrate. Biodrying was performed in 10 reactors with known air volumes from 0.88 to 6.42 L/(min x kg dry weight). To promote aeration, 5 of the reactors had 15% of a bulking agent added. The experiment lasted 20 days. After the experiments it was found that the bulking agent led to greater weight loss. However, the increased airflow rate was not linearly proportional to the weight loss.

  2. Bronchial hypersecretion, chronic airflow limitation, and peptic ulcer.

    Science.gov (United States)

    Kauffmann, F; Brille, D

    1981-11-01

    Men with and men without a history of peptic ulcers were compared using respiratory symptoms and spirographic measurements taken from data recorded in an epidemiologic study. Among the 1,049 men examined, 7% reported a history of peptic ulcer. A clear relationship appeared between bronchial hypersecretion and peptic ulcers. It persisted after adjustment for age, smoking habits, social class, and country of origin. Men with ulcers inhaled tobacco smoke more often. Ulcers, smoking, and chronic phlegm were independently related to a lower body build index. It seems that the relationship between smoking and ulcers was greater among men with chronic phlegm, and it is postulated that peptic ulcers and "chronic bronchitis" might be related to a "common secretory disorder." After adjustment for age, men with a history of peptic ulcers had, not a lower FEV1, but a higher vital capacity. A slightly lower FEV1/VC ratio cannot in such cases be considered as an index of chronic airflow limitation.

  3. Oscillating and star-shaped drops levitated by an airflow

    CERN Document Server

    Bouwhuis, Wilco; Peters, Ivo R; Brunet, Philippe; van der Meer, Devaraj; Snoeijer, Jacco H

    2013-01-01

    We investigate the spontaneous oscillations of drops levitated above an air cushion, eventually inducing a breaking of axisymmetry and the appearance of `star drops'. This is strongly reminiscent of the Leidenfrost stars that are observed for drops floating above a hot substrate. The key advantage of this work is that we inject the airflow at a constant rate below the drop, thus eliminating thermal effects and allowing for a better control of the flow rate. We perform experiments with drops of different viscosities and observe stable states, oscillations and chimney instabilities. We find that for a given drop size the instability appears above a critical flow rate, where the latter is largest for small drops. All these observations are reproduced by numerical simulations, where we treat the drop using potential flow and the gas as a viscous lubrication layer. Qualitatively, the onset of instability agrees with the experimental results, although the typical flow rates are too large by a factor 10. Our results...

  4. Induced airflow in flying insects II. Measurement of induced flow.

    Science.gov (United States)

    Sane, Sanjay P; Jacobson, Nathaniel P

    2006-01-01

    The flapping wings of insects and birds induce a strong flow over their body during flight. Although this flow influences the sensory biology and physiology of a flying animal, there are very little data on the characteristics of this self-generated flow field or its biological consequences. A model proposed in the companion paper estimated the induced flow over flying insects. In this study, we used a pair of hot wire anemometers to measure this flow at two locations near the body of a tethered flapping hawk moth, Manduca sexta. The axial inflow anemometer measured the airflow prior to its entry into the stroke plane, whereas the radial outflow anemometer measured the airflow after it crossed the stroke plane. The high temporal resolution of the hot wire anemometers allowed us to measure not only the mean induced flow but also subtle higher frequency disturbances occurring at 1-4 times the wing beat frequency. These data provide evidence for the predictions of a mathematical model proposed in the companion paper. Specifically, the absolute value of the measured induced flow matches the estimate of the model. Also, as predicted by the model, the induced flow varies linearly with wing beat frequency. Our experiments also show that wing flexion contributes significantly to the observed higher frequency disturbances. Thus, the hot wire anemometry technique provides a useful means to quantify the aerodynamic signature of wing flexion. The phasic and tonic components of induced flow influence several physiological processes such as convective heat loss and gas exchange in endothermic insects, as well as alter the nature of mechanosensory and olfactory stimuli to the sensory organs of a flying insect.

  5. Evaluation and optimization of SYBR Green real-time reverse transcription polymerase chain reaction as a tool for diagnosis of the Flavivirus genus in Brazil

    Directory of Open Access Journals (Sweden)

    Marilia Farignoli Romeiro

    2016-06-01

    Full Text Available Abstract: INTRODUCTION: The genus Flavivirus includes several pathogenic species that cause severe illness in humans. Therefore, a rapid and accurate molecular method for diagnosis and surveillance of these viruses would be of great importance. Here, we evaluate and optimize a quantitative real-time reverse transcription polymerase chain reaction (RT-PCR method for the diagnosis of the Flavivirus genus. METHODS: We evaluated different commercial kits that use the SYBR Green system for real-time RT-PCR with a primer set that amplifies a fragment of the NS5 flavivirus gene. The specificity and sensitivity of the assay were tested using twelve flaviviruses and ribonucleic acid (RNA transcribed from the yellow fever virus. Additionally, this assay was evaluated using the sera of 410 patients from different regions of Brazil with acute febrile illness and a negative diagnosis for the dengue virus. RESULTS: The real-time RT-PCR amplified all flaviviruses tested at a melting temperature of 79.92 to 83.49°C. A detection limit of 100 copies per ml was determined for this assay. Surprisingly, we detected dengue virus in 4.1% (17/410 of samples from patients with febrile illness and a supposedly negative dengue infection diagnosis. The viral load in patients ranged from 2.1×107to 3.4×103copies per ml. CONCLUSIONS: The real-time RT-PCR method may be very useful for preliminary diagnoses in screenings, outbreaks, and other surveillance studies. Moreover, this assay can be easily applied to monitor viral activity and to measure viral load in pathogenesis studies.

  6. Fault tolerant attitude control for small unmanned aircraft systems equipped with an airflow sensor array.

    Science.gov (United States)

    Shen, H; Xu, Y; Dickinson, B T

    2014-11-18

    Inspired by sensing strategies observed in birds and bats, a new attitude control concept of directly using real-time pressure and shear stresses has recently been studied. It was shown that with an array of onboard airflow sensors, small unmanned aircraft systems can promptly respond to airflow changes and improve flight performances. In this paper, a mapping function is proposed to compute aerodynamic moments from the real-time pressure and shear data in a practical and computationally tractable formulation. Since many microscale airflow sensors are embedded on the small unmanned aircraft system surface, it is highly possible that certain sensors may fail. Here, an adaptive control system is developed that is robust to sensor failure as well as other numerical mismatches in calculating real-time aerodynamic moments. The advantages of the proposed method are shown in the following simulation cases: (i) feedback pressure and wall shear data from a distributed array of 45 airflow sensors; (ii) 50% failure of the symmetrically distributed airflow sensor array; and (iii) failure of all the airflow sensors on one wing. It is shown that even if 50% of the airflow sensors have failures, the aircraft is still stable and able to track the attitude commands.

  7. The impact of smoking on airflow limitation in subjects with history of asthma and inactive tuberculosis.

    Directory of Open Access Journals (Sweden)

    Hyun Jung Kim

    Full Text Available Although smoking is the most important and modifiable cause of chronic obstructive pulmonary disease (COPD, other risk factors including asthma and tuberculosis (TB are also associated. It is common for COPD patients to have more than one of these risk factors. The aims of this study were to determine the prevalence of airflow limitation (FEV1/FVC<0.7 according to the risk factors and to investigate their impact and interaction in airflow limitation.From the Korean National Health and Nutrition Examination Survey between 2008 and 2012, we analyzed participants over 40 years of age by spirometry, chest radiograph and questionnaire about asthma and smoking history.Of 12,631 participants, 1,548 (12.3% had airflow limitation. The prevalence of airflow limitation in smokers (≥10 pack-year, asthmatics, and those with inactive TB was 23.9%, 32.1%, and 33.6%. The prevalence increased with the number of risk factors: 86.1% had airflow limitation if they had all three risk factors. Impacts of inactive TB and asthma on airflow limitation were equivalent to 47 and 69 pack-years of smoking, respectively. Airflow limitation resulted from lower levels of smoking in those with inactive TB and asthma. A potential interaction between smoking and inactive tuberculosis in the development of airflow limitation was identified (p = 0.054.Asthma and inactive TB lesions increase susceptibility to smoking in the development of airflow limitation. People with these risk factors should be seen as a major target population for anti-smoking campaigns to prevent COPD.

  8. Computational Fluid Dynamics Study on the Influence of Airflow Patterns on Carbon Dioxide Distribution in a Scaled Livestock Building

    DEFF Research Database (Denmark)

    Rong, Li; Nielsen, Peter V.; Tong, Guohong

    2008-01-01

    Airflow patterns and airflow rate have an important influence on contaminant distribution in livestock buildings. The objective of this paper is to model and evaluate the effect of airflow rates and airflow patterns effect on CO2 concentration distribution and emission rates in a scaled livestock...... building with slatted floor. Contaminant sources are assumed to be modelled as a constant concentration on the manure surface. Three different ventilation rates and two different deflector degrees are studied, in which the deflector is applied to change the airflow patterns. A CFD commercial software code...

  9. Genetic Algorithm (GA)-Based Inclinometer Layout Optimization.

    Science.gov (United States)

    Liang, Weijie; Zhang, Ping; Chen, Xianping; Cai, Miao; Yang, Daoguo

    2015-04-17

    This paper presents numerical simulation results of an airflow inclinometer with sensitivity studies and thermal optimization of the printed circuit board (PCB) layout for an airflow inclinometer based on a genetic algorithm (GA). Due to the working principle of the gas sensor, the changes of the ambient temperature may cause dramatic voltage drifts of sensors. Therefore, eliminating the influence of the external environment for the airflow is essential for the performance and reliability of an airflow inclinometer. In this paper, the mechanism of an airflow inclinometer and the influence of different ambient temperatures on the sensitivity of the inclinometer will be examined by the ANSYS-FLOTRAN CFD program. The results show that with changes of the ambient temperature on the sensing element, the sensitivity of the airflow inclinometer is inversely proportional to the ambient temperature and decreases when the ambient temperature increases. GA is used to optimize the PCB thermal layout of the inclinometer. The finite-element simulation method (ANSYS) is introduced to simulate and verify the results of our optimal thermal layout, and the results indicate that the optimal PCB layout greatly improves (by more than 50%) the sensitivity of the inclinometer. The study may be useful in the design of PCB layouts that are related to sensitivity improvement of gas sensors.

  10. Administration of colistin sulfate in endotoxic model at slow and sustained fashion may reverse shock without causing nephrotoxicity in its optimal concentration.

    Science.gov (United States)

    Haque, Anwarul; Ishii, Yoshikazu; Akasaka, Yoshikiyo; Matsumoto, Tetsuya; Tateda, Kazuhiro

    2017-07-31

    Despite of proven LPS neutralizing activity, intravenous polymyxin use was waned due to experience of associated nephrotoxicity. But, increasing resistance to all available antibiotics has necessitated their resurgence and the prodrug of colistin sulfate (CS), known as colistin-methanesulfonate (CMS), is increasingly used as the only therapeutic option in many infections. Currently available CMS employ very different dose definitions and thus because of complex pharmacokinetics/pharmacodynamics information and short half-life, this drug use remains confusing. We aimed to expose CS in endotoxic shock models by micro-osmotic pump and evaluated its effectiveness. We used micro-osmotic pumps to deliver either sterile saline or CS at different dosages ranging from 0.25mg/day to 7mg/day for consecutive 3days in LPS (8mg/kg body weight) induced endotoxic mice and observed their outcome twice daily for a week to determine the survival rate. Serum pro-inflammatory cytokine levels and apoptosis in renal tissues in these models were evaluated. We showed endotoxic shock was reversed and all mice survived with a CS administration at a dosage of 2mg/day for 3 days, in comparison to survival rate with saline administration (p=<0.0001) in endotoxic models. CS infusion in shock models using micro-osmotic pump ameliorated rising of serum TNF-α, IL-12p70 and IL-6 levels. Nephrotoxicity was evident only with a higher dosage, but not with a lower dosage which was optimum to control endotoxic shock in models. These results highlighted that an optimal dosage of CS effectively improved outcome in endotoxic shock models without causing nephrotoxicity when administered at a slow and sustained manner. And a higher CS dosage administration was nephrotoxic and fatal. Thus this study bought an opportunity to consider future investigations with CS administration in murine Gram-negative bacterial infections in a novel way. Copyright © 2017 International Society for Chemotherapy of Infection and

  11. PLETHYSMOGRAPHIC PARAMETERS IN THE ASSESSMENT OF REVERSIBILITY OF AIRWAYS OBSTRUCTION IN PATIENTS WITH CLINICAL EMPHYSEMA

    NARCIS (Netherlands)

    GIMENO, F; POSTMA, DS; VANALTENA, R

    1993-01-01

    Slow inspiratory vital capacity (IVC) and forced expiratory volume in 1 s (FEV1) before and after an inhaled beta-agonist are widely used to detect reversible airflow limitation in patients with chronic obstructive lung disease. The measurement of airways resistance (Raw) during quiet breathing with

  12. Resonant frequency does not predict high-frequency chest compression settings that maximize airflow or volume.

    Science.gov (United States)

    Luthy, Sarah K; Marinkovic, Aleksandar; Weiner, Daniel J

    2011-06-01

    High-frequency chest compression (HFCC) is a therapy for cystic fibrosis (CF). We hypothesized that the resonant frequency (f(res)), as measured by impulse oscillometry, could be used to determine what HFCC vest settings produce maximal airflow or volume in pediatric CF patients. In 45 subjects, we studied: f(res), HFCC vest frequencies that subjects used (f(used)), and the HFCC vest frequencies that generated the greatest volume (f(vol)) and airflow (f(flow)) changes as measured by pneumotachometer. Median f(used) for 32 subjects was 14 Hz (range, 6-30). The rank order of the three most common f(used) was 15 Hz (28%) and 12 Hz (21%); three frequencies tied for third: 10, 11, and 14 Hz (5% each). Median f(res) for 43 subjects was 20.30 Hz (range, 7.85-33.65). Nineteen subjects underwent vest-tuning to determine f(vol) and f(flow). Median f(vol) was 8 Hz (range, 6-30). The rank order of the three most common f(vol) was: 8 Hz (42%), 6 Hz (32%), and 10 Hz (21%). Median f(flow) was 26 Hz (range, 8-30). The rank order of the three most common f(flow) was: 30 Hz (26%) and 28 Hz (21%); three frequencies tied for third: 8, 14, and 18 Hz (11% each). There was no correlation between f(used) and f(flow) (r(2)  = -0.12) or f(vol) (r(2) = 0.031). There was no correlation between f(res) and f(flow) (r(2)  = 0.19) or f(vol) (r(2) = 0.023). Multivariable analysis showed no independent variables were predictive of f(flow) or f(vol). Vest-tuning may be required to optimize clinical utility of HFCC. Multiple HFCC frequencies may need to be used to incorporate f(flow) and f(vol).

  13. Observing and Quantifying Airflows in the Infection Control of Aerosol- and Airborne-Transmitted Diseases

    DEFF Research Database (Denmark)

    Tang, J. W.; Noakes, C. J.; Nielsen, Peter V.;

    2011-01-01

    techniques have been applied to examine the temporalespatial information about the airflow patterns and the movement of related, suspended material within this air in a hospital setting. Closer collaboration with engineers has allowed clinical microbiologists, virologists and infection control teams...

  14. Airflow patterns in the vicinity of an air-driven free reed

    Science.gov (United States)

    Jensen, Jesse T.; Cottingham, James P.

    2003-10-01

    Free reed instruments are characterized by high-volume airflow rates through the oscillating reeds. Measurements have been made of the average volume flow rate through a single American organ reed as a function of blowing pressure. In addition, measurements of average air velocity have been made at a grid of points close to the vibrating air-driven reed, mounted on the surface of a laboratory wind chest. These measurements supplement earlier investigations, which explored relations among the reed motion, airflow, and acoustic pressure associated with the vibration of free reeds. [M. Busha and J. P. Cottingham, J. Acoust. Soc. Am. 111, 2376 (2002)]. An attempt has been made to determine whether the left-right asymmetry due to the asymmetric shape (twist) of the reed is reflected in the airflow pattern. A graphing program has been developed so that the airflow pattern can be visualized in two or three dimensions.

  15. Turbulent airflow meter for long-term monitoring in patient-ventilator circuits.

    Science.gov (United States)

    Elliott, S E; Shore, J H; Barnes, C W; Lindauer, J; Osborn, J J

    1977-03-01

    A new type of flowmeter is described which operates on the principle that pressure drop (deltaP) produced by turbulent volume flow (V) through a simple resistance chamber obeys a relation of V = K (deltaP)0.50. Data are given showing that the device follows a true power law with a single exponent for airflows ranging from 3.5 to 270 l/min. Standard instrumentation and a linearization circuit are used with the new flowmeter to provide linear steady-state and alternating airflow measurements up to peak rates of 150 l/min and frequency to 15 Hz. Data are presented comparing integrated airflow readings from the new turbulent flowmeter and a laminar-type flowmeter. The turbulent airflow meter appears to offer increased reliability for long-term patient monitoring use in patient-ventilator circuits.

  16. Intermittent Coffee Drying in Deep Bed with Pulsed Airflow Secado de Café en Lecho Fijo con Intermitencia Térmica y Flujo de Aire Pulsado

    Directory of Open Access Journals (Sweden)

    Héctor José Ciro Velásquez

    2011-12-01

    Full Text Available A dryer in deep bed without airflow reversal was adapted to work simultaneously with thermal intermittence and pulsed airflow in the drying of parchment coffee bean. The dryer was operated by cycles of thermal intermittence for a heating temperature of 55 °C and cooling of 40 and 25 °C. The results showed that the increase of temperature in the cycle of cooling tends to increase the water removal and that the increase of the number of air pulses without reversal of the direction of air flow causes an excessive moisture gradient within the batch. Moreover, the specific energy requirement of the dryer was from 15 to 25 MJ/kg, showing the best thermal performance for the condition in which the dryer was operate without pulsed airflow.Un secador de lecho fijo fue adaptado para trabajar de forma simultánea con intermitencia térmica y flujo de aire pulsado sin inversión de flujo de aire, en el secado de granos de café. El secador fue operado con ciclos de intermitencia térmica para una temperatura de calentamiento de 55 °C y enfriamiento de 40 y 25 °C. Los resultados mostraron que el aumento de temperatura en el ciclo de enfriamiento, tiende a incrementar la remoción de agua y que el aumento del número de pulsos de aire sin inversión del flujo de dirección del aire, ocasiona un secado deficiente debido al excesivo gradiente de humedad ocasionado en la capa de producto. Adicionalmente, se encontró que el consumo de energía específica del secador varió entre 15 y 25 MJ/kg de agua evaporada, siendo el mejor rendimiento termo energético para la condición en la cual el secador fue operado sin flujo de aire pulsado.

  17. Reverse logistics

    NARCIS (Netherlands)

    M.P. de Brito (Marisa); S.D.P. Flapper; R. Dekker (Rommert)

    2002-01-01

    textabstractThis paper gives an overview of scientific literature that describes and discusses cases of reverse logistics activities in practice. Over sixty case studies are considered. Based on these studies we are able to indicate critical factors for the practice of reverse logistics. In addi

  18. Effect of near-wall treatments on airflow simulations

    CERN Document Server

    Gharbi, Najla El; Benzaoui, Ahmed; Amara, E H

    2010-01-01

    Airflow simulation results depend on a good prediction of near wall turbulence. In this paper a comparative study between different near wall treatments is presented. It is applied to two test cases: (1) the first concerns the fully developed plane channel flow (i.e. the flow between two infinitely large plates). Simulation results are compared to direct numerical simulation (DNS) data of Moser et al. (1999) for $Re\\tau$ = 590 (where $Re\\tau$ denotes the friction Reynolds number defined by friction velocity $u\\tau$, kinematics viscosity $v$ and the channel half-width $\\delta$); (2) the second case is a benchmark test for room air distribution (Nielsen, 1990). Simulation results are compared to experimental data obtained with laser-doppler anemometry. Simulations were performed with the aid of the commercial CFD code Fluent (2005). Near wall treatments available in Fluent were tested: Standard Wall Functions, Non Equilibrium Wall Function and Enhanced Wall Treatment. In each case, suitable meshes with adequate...

  19. Airflow obstruction: is it asthma or is it COPD?

    Directory of Open Access Journals (Sweden)

    Rogliani P

    2016-11-01

    Full Text Available Paola Rogliani, Josuel Ora, Ermanno Puxeddu, Mario Cazzola Department of Systems Medicine, Tor Vergata University of Rome, Rome, Italy Abstract: Despite the availability of guideline recommendations, diagnostic confusion between COPD and asthma appears common, and often it is very difficult to decide whether the obstruction is caused by asthma or COPD in a patient with airway obstruction. However, there are well-defined features that help in differentiating asthma from COPD in the presence of fixed airflow obstruction. Nonetheless, the presentations of asthma and COPD can converge and mimic each other, making it difficult to give these patients a diagnosis of either condition. The association of asthma and COPD in the same patient has been designated mixed asthma–COPD phenotype or overlap syndrome. However, since the absence of a clear definition and the inclusion of patients with different characteristics under this umbrella term, it may not facilitate treatment decisions, especially in the absence of clinical trials addressing this heterogeneous population. We are realizing that neither asthma nor COPD are single diseases, but rather syndromes consisting of several endotypes and phenotypes, consequently comprising a spectrum of diseases that must be recognized and adequately treated with targeted therapy. Therefore, we must treat patients by personalizing therapy on the basis of those treatable traits present in each subject. Keywords: airway obstruction, asthma, ACOS, chronic obstructive pulmonary disease

  20. Factors affecting distribution of airflow in a human tracheobronchial cast.

    Science.gov (United States)

    Cohen, B S; Sussman, R G; Lippmann, M

    1993-09-01

    Air velocity was measured at end airways of hollow replicate casts of the human tracheobronchial tree in order to determine the flow distribution within casts extending to 3 mm diameter airways. Measurements were made by hot-wire anemometry for constant inspiratory flow rates of 7.5, 15, 30 and 60 L.min-1. Average flow distribution among the lung lobes was as follows: right upper, 18.5%; right middle, 9.2%; right lower, 32.3%; left upper, 15.7%; and left lower, 24.3%. An empirical model derived from the experimental flow distribution data demonstrated the effect of various morphometric parameters of the hollow cast on the distribution of airflow. Airway cross-sectional area, branching angle and total path-length were found to have the greatest influence. As the tracheal flow rate decreased from 60 to 7.5 L.min-1, the influence of branching angle was reduced, while total path-length became more influential. These results provide evidence for the transition of flow regimes within the TB tree within normal physiological flow ranges.

  1. Pulsatile airflow during phonation: an excised larynx model.

    Science.gov (United States)

    Alipour, F; Scherer, R C

    1995-02-01

    Pulsatile airflow in the excised larynx was investigated with simultaneous recordings of air velocity, subglottal pressure, volume flow, and the electroglottograph signal for various conditions of the larynx. Canine larynges were mounted on a bench with sutures attached to cartilages to mimic the function of laryngeal muscles. Sustained oscillations were established and maintained with the flow of heated and humidified air through the trachea. The instantaneous air velocity above the glottis, which is the summation of a periodic velocity and the turbulent component, was measured with a constant temperature hot-wire probe at various locations. The phase-averaged velocity was used to construct the patterns of jet flow at selected time frames of the oscillation cycle. Results suggest that supraglottal air velocity is highly spatially and temporally dependent. Cycles of local air velocity with double peaks were not uncommon and a case is provided. For one phase-averaged phonatory cycle, a 9 x 13 velocity measurement grid demonstrated strongly nonuniform velocity surfaces for eight phases of the cycle, with greater velocities located anteriorly.

  2. Field investigation on Salixpsammophila plant morphology and airflow structure

    Institute of Scientific and Technical Information of China (English)

    Wang Lei; Wang Zhi; Liu Lianyou; Hasi Eerdon; Sun Bingyan; Tang Yan

    2006-01-01

    The field investigation was undertaken to determin the characteristics of Salix psammophila plant morphdogy and airflow structure of single-line S.psammophila on the southern edge of the Mu Su sandland.The results showed that artificially cultivated single-line S.psammophila could accumulate sand because the plant decreased the windward and leeward wind velocity.There was a significant correlation (R = 0.696) between accumulated sand volume (V2) and plant volume (V1).The wind velocity was 6 m/s at a 4 m height of single-line S.psammophilahedge row.The wind velocity decreased at 3 H windward and increased at 2 H to windward.The wind velocity then steeply decreased to leeward and reached its lowest value at 1 H to leeward and gradually recovered to the open field velocity.The protection distance of the single-line S.psammophila was about 17 H' and the effective protection distance was aboui 13 H'.Single-line S.psammophila had few effects on the wind velocity when the wind was above the plant height.

  3. Bioinspired carbon nanotube fuzzy fiber hair sensor for air-flow detection.

    Science.gov (United States)

    Maschmann, Matthew R; Ehlert, Gregory J; Dickinson, Benjamin T; Phillips, David M; Ray, Cody W; Reich, Greg W; Baur, Jeffery W

    2014-05-28

    Artificial hair sensors consisting of a piezoresistive carbon-nanotube-coated glass fiber embedded in a microcapillary are assembled and characterized. Individual sensors resemble a hair plug that may be integrated in a wide range of host materials. The sensors demonstrate an air-flow detection threshold of less than 1 m/s with a piezoresistive sensitivity of 1.3% per m/s air-flow change.

  4. Continuous nanofiber yarns twisted through three-dimensional high-speed swirling airflow

    Directory of Open Access Journals (Sweden)

    He Jian-Xin

    2013-01-01

    Full Text Available A new method is proposed to fabricate continuous twisted nanofiber yarns. Nanofibers are bunched by a double conjugate electrospinning, and then twisted through a three-dimensional high-speed swirling airflow. Its principle and process are analyzed theoretically, and the airflow field inside the nozzle chamber is studied numerically, and mechanical properties of nanofiber yarns at different spinning conditions are systematically discussed.

  5. Modeling Airflow Using Subject-Specific 4DCT-Based Deformable Volumetric Lung Models

    OpenAIRE

    Olusegun J. Ilegbusi; Zhiliang Li; Behnaz Seyfi; Yugang Min; Sanford Meeks; Patrick Kupelian; Santhanam, Anand P.

    2012-01-01

    Lung radiotherapy is greatly benefitted when the tumor motion caused by breathing can be modeled. The aim of this paper is to present the importance of using anisotropic and subject-specific tissue elasticity for simulating the airflow inside the lungs. A computational-fluid-dynamics (CFD) based approach is presented to simulate airflow inside a subject-specific deformable lung for modeling lung tumor motion and the motion of the surrounding tissues during radiotherapy. A flow-structure inter...

  6. Effect of air-flow rate and turning frequency on bio-drying of dewatered sludge.

    Science.gov (United States)

    Zhao, Ling; Gu, Wei-Mei; He, Pin-Jing; Shao, Li-Ming

    2010-12-01

    Sludge bio-drying is an approach for biomass energy utilization, in which sludge is dried by means of the heat generated by aerobic degradation of its organic substances. The study aimed at investigating the interactive influence of air-flow rate and turning frequency on water removal and biomass energy utilization. Results showed that a higher air-flow rate (0.0909m(3)h(-1)kg(-1)) led to lower temperature than did the lower one (0.0455m(3)h(-1)kg(-1)) by 17.0% and 13.7% under turning per two days and four days. With the higher air-flow rate and lower turning frequency, temperature cumulation was almost similar to that with the lower air-flow rate and higher turning frequency. The doubled air-flow rate improved the total water removal ratio by 2.86% (19.5gkg(-1) initial water) and 11.5% (75.0gkg(-1) initial water) with turning per two days and four days respectively, indicating that there was no remarkable advantage for water removal with high air-flow rate, especially with high turning frequency. The heat used for evaporation was 60.6-72.6% of the total heat consumption (34,400-45,400kJ). The higher air-flow rate enhanced volatile solids (VS) degradation thus improving heat generation by 1.95% (800kJ) and 8.96% (3200kJ) with turning per two days and four days. With the higher air-flow rate, heat consumed by sensible heat of inlet air and heat utilization efficiency for evaporation was higher than the lower one. With the higher turning frequency, sensible heat of materials and heat consumed by turning was higher than lower one.

  7. Investigation on side-spray fluidized bed granulation with swirling airflow.

    Science.gov (United States)

    Wong, Poh Mun; Chan, Lai Wah; Heng, Paul Wan Sia

    2013-03-01

    Top-spray fluidized bed granulation with axial fluidization airflow from the bottom of the granulator is well-established in the pharmaceutical industry. The application of swirling airflow for fluidized bed granulation was more recently introduced. This study examined the effects of various process parameters on the granules produced by side-spray fluidized bed with swirling airflow using the central composite and Box-Behnken design of experiment. Influence of the amount of binder solution, spray rate, and distance between spray nozzle and powder bed were initially studied to establish operationally viable values for these parameters. This was followed by an in-depth investigation on the effects of inlet airflow rate, atomizing air pressure and distance between spray nozzle and powder bed on granule properties. It was found that the amount of binder solution had a positive correlation with granule size and percentage of lumps but a negative correlation with size distribution and Hausner ratio of the granules. Binder solution spray rate was also found to affect the granules size. High drug content uniformity was observed in all the batches of granules produced. Both inlet airflow rate and atomizing air pressure were found to correlate negatively with granule size and percentage of lumps but correlate positively with the size distribution of the granule produced. Percentage of fines was found to be significantly affected by inlet airflow rate. Distance between spray nozzle and powder bed generally affected the percentage of lumps.

  8. Airflow in the Human Nasal Passage and Sinuses of Chronic Rhinosinusitis Subjects.

    Directory of Open Access Journals (Sweden)

    Haribalan Kumar

    Full Text Available Endoscopic surgery is performed on patients with chronic inflammatory disease of the paranasal sinuses to improve sinus ventilation. Little is known about how sinus surgery affects sinonasal airflow. In this study nasal passage geometry was reconstructed from computed tomographic imaging from healthy normal, pre-operative, and post-operative subjects. Transient air flow through the nasal passage during calm breathing was simulated. Subject-specific differences in ventilation of the nasal passage were observed. Velocity magnitude at ostium was different between left and right airway. In FESS, airflow in post-surgical subjects, airflow at the maxillary sinus ostium was upto ten times higher during inspiration. In a Lothrop procedure, airflow at the frontal sinus ostium can be upto four times higher during inspiration. In both post-operative subjects, airflow at ostium was not quasi-steady. The subject-specific effect (of surgery on sinonasal interaction evaluated through airflow simulations may have important consequences for pre- and post-surgical assessment and surgical planning, and design for improvement of the delivery efficiency of nasal therapeutics.

  9. Airflow adjustment and minimization of the air power of ventilation network

    Institute of Scientific and Technical Information of China (English)

    INOUE Masahiro; YANG Wen-yu

    2011-01-01

    It is often required to know which roadway (adjustment roadway) resistances and how much values of the resistances should be changed to make the airflow rates in roadways (target roadways) to certain required values in the practice of mine ventilation.In this case,the airflow rates of the target roadways and the resistances of the roadways other than the adjustment roadways are the given conditions and the resistances of the adjustment roadways are the solutions to be found.No straightforward method to solve the problem has been found up to now.Therefore,trial and error method using the ventilation network analysis program is utilized to solve the problem so far.The method takes long calculation time and the best answer is not necessarily obtained.The authors newly defmed "airflow element" as an element of the ventilation network analysis.The resistances that satisfy the airflow requirements can be calculated straight forwardly by putting the function of the airflow element into the ventilation network analysis.The air power required for the ventilation can be minimized while meeting the airflow requirements by the advanced application of the method.The authors made the computer program fulfill the method.The program was applied to actual ventilation network and it was found that the method is very practical and the time required for the analysis is short.

  10. Measurement of the resistivity of porous materials with an alternating air-flow method.

    Science.gov (United States)

    Dragonetti, Raffaele; Ianniello, Carmine; Romano, Rosario A

    2011-02-01

    Air-flow resistivity is a main parameter governing the acoustic behavior of porous materials for sound absorption. The international standard ISO 9053 specifies two different methods to measure the air-flow resistivity, namely a steady-state air-flow method and an alternating air-flow method. The latter is realized by the measurement of the sound pressure at 2 Hz in a small rigid volume closed partially by the test sample. This cavity is excited with a known volume-velocity sound source implemented often with a motor-driven piston oscillating with prescribed area and displacement magnitude. Measurements at 2 Hz require special instrumentation and care. The authors suggest an alternating air-flow method based on the ratio of sound pressures measured at frequencies higher than 2 Hz inside two cavities coupled through a conventional loudspeaker. The basic method showed that the imaginary part of the sound pressure ratio is useful for the evaluation of the air-flow resistance. Criteria are discussed about the choice of a frequency range suitable to perform simplified calculations with respect to the basic method. These criteria depend on the sample thickness, its nonacoustic parameters, and the measurement apparatus as well. The proposed measurement method was tested successfully with various types of acoustic materials.

  11. Effects of vowel height and vocal intensity on anticipatory nasal airflow in individuals with normal speech.

    Science.gov (United States)

    Young, L H; Zajac, D J; Mayo, R; Hooper, C R

    2001-02-01

    The purpose of this study was to determine the effects of vowel height and vocal intensity on the magnitude of anticipatory nasal airflow in normal speakers when producing vowel-nasal-vowel (VNV) sequences. Measurements of nasal and oral airflow were obtained from 15 men and 12 women with normal speech during production of the VNV sequences /ini/ and /ana/ at low, medium, and high intensity levels. Ratios of nasal to oral-plus-nasal airflow were calculated for the initial vowel of both utterances at each of the intensity levels. Analysis of variance (ANOVA) procedures indicated a significant main effect of intensity level and a significant vowel-by-sex interaction effect (p vowel type. Female speakers exhibited greater airflow ratios during production of /ini/ than during productions of /ana/. Their airflow ratios were also greater during production of /ini/ than were those of male speakers. The results suggest that vocal intensity may affect velopharyngeal (VP) function in an assimilative nasal phonetic context. The results further suggest that anticipatory nasal airflow may be determined by the configuration of the oral cavity to a greater extent in women than in men. Theoretical and clinical implications are discussed.

  12. Robust optimization for multi-product two-stage reverse logistics reproduction network%逆向物流多产品两阶段再生产网络鲁棒优化

    Institute of Scientific and Technical Information of China (English)

    孙强; 沈玉志; 李士金

    2015-01-01

    考虑不同周期内逆向物流回收数量的不确定性和再生产设备的生产能力约束,将逆向物流回收数量、再生产成本和市场需求作为不确定参数,以成本最小为目标,建立了包含生产成本、设备运作成本、库存成本在内的多周期多产品两阶段逆向物流网络鲁棒优化模型。通过算例验证了模型的有效性。%Considering the uncertainty of recycling quantity and the capacity constrained of the reproduction equipment in different periods during the reverse logistics operation, a multi-period multi-product two-stage robust optimized model with the goal of minimizing the total cost of reverse logistics network including production cost and equipment running cost and inventory cost which lets the recycling quantity of reverse logistics and reproduction cost as well as market demand be the uncertain parameters considering the uncertainty of recycling quantity and the capacity constrained of the reproduction equipment in different periods during the reverse logistics operation is established. An example is given to illustrate and verify the validity and effectiveness of the model.

  13. Testing limits to airflow perturbation device (APD measurements

    Directory of Open Access Journals (Sweden)

    Jamshidi Shaya

    2008-10-01

    Full Text Available Abstract Background The Airflow Perturbation Device (APD is a lightweight, portable device that can be used to measure total respiratory resistance as well as inhalation and exhalation resistances. There is a need to determine limits to the accuracy of APD measurements for different conditions likely to occur: leaks around the mouthpiece, use of an oronasal mask, and the addition of resistance in the respiratory system. Also, there is a need for resistance measurements in patients who are ventilated. Method Ten subjects between the ages of 18 and 35 were tested for each station in the experiment. The first station involved testing the effects of leaks of known sizes on APD measurements. The second station tested the use of an oronasal mask used in conjunction with the APD during nose and mouth breathing. The third station tested the effects of two different resistances added in series with the APD mouthpiece. The fourth station tested the usage of a flexible ventilator tube in conjunction with the APD. Results All leaks reduced APD resistance measurement values. Leaks represented by two 3.2 mm diameter tubes reduced measured resistance by about 10% (4.2 cmH2O·sec/L for control and 3.9 cm H2O·sec/L for the leak. This was not statistically significant. Larger leaks given by 4.8 and 6.4 mm tubes reduced measurements significantly (3.4 and 3.0 cm cmH2O·sec/L, respectively. Mouth resistance measured with a cardboard mouthpiece gave an APD measurement of 4.2 cm H2O·sec/L and mouth resistance measured with an oronasal mask was 4.5 cm H2O·sec/L; the two were not significantly different. Nose resistance measured with the oronasal mask was 7.6 cm H2O·sec/L. Adding airflow resistances of 1.12 and 2.10 cm H2O·sec/L to the breathing circuit between the mouth and APD yielded respiratory resistance values higher than the control by 0.7 and 2.0 cm H2O·sec/L. Although breathing through a 52 cm length of flexible ventilator tubing reduced the APD

  14. Relationship between lightning activity and vertical airflow characteristics in thunderstorms

    Science.gov (United States)

    Wang, Chenxi; Zheng, Dong; Zhang, Yijun; Liu, Liping

    2017-07-01

    Cloud-to-ground (CG) lightning data, wind field data derived from dual-Doppler radars, and radar reflectivity data are combined to investigate the relationships between CG lightning and the parameters associated with vertical airflow. A new method for the identification of thunderstorm cells based on the aggregation of flashes is developed. It is found that approximately 79.1% of CG flashes are located in the region featuring weak vertical velocity at the 0 °C level, ranging from - 5 to 5 m s- 1, with the majority in the weak updraft region, especially for negative CG lightning and the CG lightning in the initial stage of thunderstorms. The CG lightning rate is correlated with the volume of updraft for vertical velocities within certain limits. The sum of absolute precipitation ice mass flux in the region from 7 to 11 km is more significantly correlated with the CG flash rate, with correlation coefficients of 0.73, 0.71, and 0.74 for the initial, mature, and dissipating stages of thunderstorms, respectively. On average, the updraft in the thunderstorm at the stage when the last CG flash occurs accounts for a much smaller ratio to the whole volume of the thunderstorm than that corresponding to the first CG flash. The maximum updraft and maximum height of the 10 and 20 m s- 1 updraft speeds are close for the first and last CG flashes, indicating the dependence of the lightning on strength of updraft. It is deduced that layered large-range charges may be more conducive to the generation of CG flashes than charge pockets in the thunderstorm.

  15. Rain-induced subsurface airflow and Lisse effect

    Science.gov (United States)

    Guo, H.; Jiao, J.J.; Weeks, E.P.

    2008-01-01

    Water-level increase after rainfall is usually indicative of rainfall recharge to groundwater. This, however, may not be true if the Lisse effect occurs. This effect represents the water-level increase in a well driven by airflow induced by an advancing wetting front during highly intensive rains. The rainwater, which may behave like a low-permeability lid, seals the ground surface so that the air pressure beneath the wetting front is increased because of air compression due to downward movement of the wetting front. A rapid and substantial rise of the water level in the well screened below water table, which bears no relationship to groundwater recharge, can be induced when various factors such as soil properties and the rain-runoff condition combine favorably. A transient, three-dimensional and variably saturated flow model was employed to study the air and groundwater flows in the soil under rain conditions. The objectives of this paper are two-fold: to evaluate the reliability of the theory of the Lisse effect presented by Weeks to predict its magnitude in modeled situations that mimic the physical complexity of real aquifers, and to conduct parametric studies on the sensitivity of the water-level rise in the well to soil properties and the rain event. The simulation results reveal that the magnitude of the Lisse effect increases with the ponding depth. Soil permeability plays a key role in generating the Lisse effect. The water-level rise in the well is delayed relative to the air-pressure rise in the unsaturated zone when the soil permeability is low, and the maximum water-level rise is less than the maximum air pressure induced by rain infiltration. The simulation also explores the sensitivity of the Lisse effect to the van Genuchten parameters and the water table depth. Copyright 2008 by the American Geophysical Union.

  16. Study on Optimization of Packaging Material Reverse Logistics Process Based on Supply Chain Environment%基于供应链环境优化包装物逆向物流运作研究

    Institute of Scientific and Technical Information of China (English)

    王冬冰

    2014-01-01

    论述了包装物逆向物流运作的内涵、必要性、意义以及传统包装物逆向物流与供应链环境下包装物逆向物流的运作特征,并从包装物逆向物流的制度规范、信息管理、包装物处理办法等方面对逆向物流的优化展开了讨论。%In this paper, we discussed the connotation, necessity, and significance of the packaging material reverse logistics operations, as well as its characteristics in the supply chain environment and then from multiple aspects, analyzed the optimization of the reverse logistics process.

  17. The characteristics of sea fog with different airflow over the Huanghai Sea in boreal spring

    Institute of Scientific and Technical Information of China (English)

    HUANG Jian; WANG Xin; ZHOU Wen; HUANG Huijun; WANG Dongxiao; ZHOU Faxiu

    2010-01-01

    Using the observations from ICOADS datasets and contemporaneous NCEP/NCAR reanalysis datasets during 1960-2002, the study classifies the airflows in favor of sea fog over the Huang-hai (Yellow) Sea in boreal spring (April-May) with the method of trajectory analysis, and analyzes the changes of proportions of warm and cold sea fogs along different paths of airflow. According to the heat balance equation, we investigate the relationships between the marine meteorological conditions and the proportion of warm and cold sea fog along different airflow paths. The major results are summarized as follows. (1) Sea fogs over the Huanghai Sea in spring are not only warm fog but also cold fog. The proportion of warm fog only accounts for 44% in April, while increases as high as 57% in May. (2) Four primary airflow paths leading to spring sea fog are identified. They are originated from the northwest, east, southeast and southwest of the Huanghai Sea, respectively. The occurrence ratios of the warm sea fog along the east and southeast airflow paths are high of 55% and 70%, while these along the southwest and northwest airflow paths are merely 17.9% and 50%. (3) The key physical processes governing the warm/cold sea fog are heat advection transport, longwave radiation cooling at fog top, solar shortwave warming and latent heat flux between air-sea interfaces. (4) The characteristics of sea fog along the four airflow paths relate closely to the conditions of water vapor advection, and the vertical distribution of relative humidity.

  18. Airflow Measurement of the Car HVAC Unit Using Hot-wire Anemometry

    Directory of Open Access Journals (Sweden)

    Fojtlín Miloš

    2016-01-01

    Full Text Available Thermal environment in a vehicular cabin significantly influence drivers’ fatigue and passengers’ thermal comfort. This environment is traditionally managed by HVAC cabin system that distributes air and modifies its properties. In order to simulate cabin thermal behaviour, amount of the air led through car vents must be determined. The aim of this study was to develop methodology to measure airflow from the vents, and consequently calculate corresponding air distribution coefficients. Three climatic cases were selected to match European winter, summer, and spring / fall conditions. Experiments were conducted on a test vehicle in a climatic chamber. The car HVAC system was set to automatic control mode, and the measurements were executed after the system stabilisation—each case was independently measured three times. To be able to evaluate precision of the method, the airflow was determined at the system inlet (HVAC suction and outlet (each vent, and the total airflow values were compared. The airflow was calculated by determining a mean value of the air velocity multiplied by an area of inlet / outlet cross-section. Hot-wire anemometry was involved to measure the air velocity. Regarding the summer case, total airflow entering the cabin was around 57 l s-1 with 60 % of the air entering the cabin through dashboard vents; no air was supplied to the feet compartment. The remaining cases had the same total airflow of around 42 l s-1, and the air distribution was focused mainly on feet and windows. The inlet and outlet airflow values show a good match with a maximum mass differential of 8.3 %.

  19. Airflow Measurement of the Car HVAC Unit Using Hot-wire Anemometry

    Science.gov (United States)

    Fojtlín, Miloš; Planka, Michal; Fišer, Jan; Pokorný, Jan; Jícha, Miroslav

    2016-03-01

    Thermal environment in a vehicular cabin significantly influence drivers' fatigue and passengers' thermal comfort. This environment is traditionally managed by HVAC cabin system that distributes air and modifies its properties. In order to simulate cabin thermal behaviour, amount of the air led through car vents must be determined. The aim of this study was to develop methodology to measure airflow from the vents, and consequently calculate corresponding air distribution coefficients. Three climatic cases were selected to match European winter, summer, and spring / fall conditions. Experiments were conducted on a test vehicle in a climatic chamber. The car HVAC system was set to automatic control mode, and the measurements were executed after the system stabilisation—each case was independently measured three times. To be able to evaluate precision of the method, the airflow was determined at the system inlet (HVAC suction) and outlet (each vent), and the total airflow values were compared. The airflow was calculated by determining a mean value of the air velocity multiplied by an area of inlet / outlet cross-section. Hot-wire anemometry was involved to measure the air velocity. Regarding the summer case, total airflow entering the cabin was around 57 l s-1 with 60 % of the air entering the cabin through dashboard vents; no air was supplied to the feet compartment. The remaining cases had the same total airflow of around 42 l s-1, and the air distribution was focused mainly on feet and windows. The inlet and outlet airflow values show a good match with a maximum mass differential of 8.3 %.

  20. Airflow limitations in pregnant women suspected of sleep-disordered breathing.

    Science.gov (United States)

    Bourjeily, Ghada; Fung, Jennifer Y; Sharkey, Katherine M; Walia, Palak; Kao, Mary; Moore, Robin; Martin, Susan; Raker, Christina A; Millman, Richard P

    2014-05-01

    Pregnancy physiology may predispose women to the development of airflow limitations during sleep. The goal of this study was to evaluate whether pregnant women suspected of sleep-disordered breathing (SDB) are more likely to have airflow limitations compared to non-pregnant controls. We recruited pregnant women referred for polysomnography for a diagnosis of SDB. Non-pregnant female controls matched for age, body mass index (BMI), and apnoea-hypopnoea index (AHI) were identified from a database. We examined airflow tracings for changes in amplitude and shape. We classified airflow limitation by (a) amplitude criteria defined as decreased airflow of > or =10 s without desaturation or arousal (FL 10), or decreased airflow of any duration combined with either 1-2% desaturation or arousal, (FL 1-2%); and (b) shape criteria defined as the presence of flattening or oscillations of the inspiratory flow curve. We identified 25 case-control pairs. Mean BMI was 44.0±6.9 in cases and 44.1±7.3 in controls. Using shape criteria, pregnant women had significantly more flow-limited breaths throughout total sleep time (32.4±35.8 vs. 9.4±17.9, ppregnant controls. In a subgroup analysis, pregnant women without a diagnosis of obstructive sleep apnoea (OSA) who had an AHI pregnant women and controls (p=0.22). Pregnant women suspected of OSA have more frequent shape-defined airflow limitations than non-pregnant controls, even when they do not meet polysomnographic OSA criteria. Copyright © 2014 Elsevier B.V. All rights reserved.

  1. Optimal Design in Combined Process of Membrane Bioreactor and Reverse Osmosis%膜生物反应器+反渗透组合工艺的优化设计探讨

    Institute of Scientific and Technical Information of China (English)

    梁智飞

    2011-01-01

    Taking waste leachate treatment project in a north city as an example, the optimal design of combined process of membrane hioreactor and reverse osmosis was discussed by putting forward the design difficulties and modified process plan with local region feature.%以北方某城市的垃圾渗沥液处理项目为例,通过提出针对具有地区特点的设计重难点及工艺改良方案,探讨采用膜生物反应器+反渗透组合工艺的优化设计.

  2. Airflow attenuation and bed net utilization: observations from Africa and Asia

    Directory of Open Access Journals (Sweden)

    von Seidlein Lorenz

    2012-06-01

    Full Text Available Abstract Background/Methods Qualitative studies suggest that bed nets affect the thermal comfort of users. To understand and reduce this discomfort the effect of bed nets on temperature, humidity, and airflow was measured in rural homes in Asia and Africa, as well as in an experimental wind tunnel. Two investigators with architectural training selected 60 houses in The Gambia, Tanzania, Philippines, and Thailand. Data-loggers were used to measure indoor temperatures in hourly intervals over a 12 months period. In a subgroup of 20 houses airflow, temperature and humidity were measured at five-minute intervals for one night from 21.00 to 6.00 hrs inside and outside of bed nets using sensors and omni-directional thermo-anemometers. An investigator set up a bed net with a mesh size of 220 holes per inch2 in each study household and slept under the bed net to simulate a realistic environment. The attenuation of airflow caused by bed nets of different mesh sizes was also measured in an experimental wind tunnel. Results The highest indoor temperatures (49.0 C were measured in The Gambia. During the hottest months of the year the mean temperature at night (9 pm was between 33.1 C (The Gambia and 26.2 C (Thailand. The bed net attenuated the airflow from a minimum of 27% (Philippines to a maximum of 71% (The Gambia. Overall the bed nets reduced airflow compared to un-attenuated airflow from 9 to 4 cm sec-1 or 52% (p -2 reduced airflow by 55% (mean; range 51 - 73%. A denser net (200 holes inch-2 attenuated airflow by 59% (mean; range 56 - 74%. Discussion Despite concerted efforts to increase the uptake of this intervention in many areas uptake remains poor. Bed nets reduce airflow, but have no influence on temperature and humidity. The discomfort associated with bed nets is likely to be most intolerable during the hottest and most humid period of the year, which frequently coincides with the peak of malaria vector densities and the force

  3. Using Computational Fluid Dynamics to examine airflow characteristics in Empty Nose Syndrome

    Science.gov (United States)

    Flint, Tim; Esmaily-Moghadam, Mahdi; Thamboo, Andrew; Velasquez, Nathalia; Nayak, Jayakar V.; Sellier, Mathieu; Moin, Parviz

    2016-11-01

    The enigmatic disorder, empty nose syndrome (ENS), presents with a complex subjective symptom profile despite objectively patent nasal airways, and recent reports suggest that surgical augmentation of the nasal airway can improve quality of life and ENS-related complaints. In this study, computational fluid dynamics (CFD) was performed both prior to, and following, inferior turbinate augmentation to model the resultant changes in airflow patterns and better understand the pathophysiology of ENS. An ENS patient with marked reduction in ENS symptoms following turbinate augmentation was identified, and pre- and post-operative CT imaging was collected. A Finite element framework with the variational multiscale method (Esmaily-Moghadam, Comput. Methods Appl. Mech. Engrg. 2015) was used to compute the airflow, temperature, and moisture transport through the nasal cavity. Comparison of the CFD results following corrective surgery showed higher levels of airflow turbulence. Augmentation produced 50%, 25%, and 25% increases in root mean square pressure, wall shear stress, and heat flux respectively. These results provide insight into the changes in nasal airflow characteristics attainable through surgical augmentation, and by extension, how nasal airflow patterns may be distorted in the 'overly patent' airway of ENS patients. Supported by Stanford University CTR and Fulbright New Zealand.

  4. Effects of airflow on the distribution of filaments in atmospheric AC dielectric barrier discharge

    Science.gov (United States)

    Fan, Zhihui; Qi, Haicheng; Liu, Yidi; Yan, Huijie; Ren, Chunsheng

    2016-12-01

    Atmospheric-pressure dielectric barrier discharge (DBD) accompanied by airflow has attracted a significant attention for its extensive applications. In this paper, the effects of airflow on the characteristics of the atmospheric air DBD plasma are experimentally investigated using the DBD reactor excited by a 15 kHz AC power source. In order to study the discharge filaments distribution at different flow rates, transparent conductive indium tin oxide film is used as the upper electrode, and quartz glasses are used as insulated dielectrics. Experiment results prove that the breakdown voltage is decreased and more current pulses with declined amplitudes are produced when the airflow is introduced into the discharge gap. It is confirmed that although the discharge seems to be diffuse in the presence of airflow to the naked eyes, the discharge mode remains filamentary in the intensified charge-coupled device images within a single AC cycle. By acquiring the images with a different exposure time, it can be recognized that the discharge filaments move along the flow field direction with a velocity less than the corresponding flow rate. The movement of discharge filaments is attributed to the motion of the charge induced by the airflow.

  5. Airflow attenuation and bed net utilization: observations from Africa and Asia

    DEFF Research Database (Denmark)

    von Seidlein, Lorenz; Ikonomidis, Konstantin; Bruun, Rasmus

    2012-01-01

    Background/Methods Qualitative studies suggest that bed nets affect the thermal comfort of users. To understand and reduce this discomfort the effect of bed nets on temperature, humidity, and airflow was measured in rural homes in Asia and Africa, as well as in an experimental wind tunnel. Two...... of airflow caused by bed nets of different mesh sizes was also measured in an experimental wind tunnel. Results The highest indoor temperatures (49.0 C) were measured in The Gambia. During the hottest months of the year the mean temperature at night (9 pm) was between 33.1 C (The Gambia) and 26.2 C (Thailand...... was detected between the inside and outside of the bed net. Wind tunnel experiments with 11 different mesh-sized bed nets showed an overall reduction in airflow of 64% (range 55 - 71%) compared to un-attenuated airflow. As expected, airflow decreased with increasing net mesh size. Nets with a mesh of 136 holes...

  6. Computer simulation of airflow through a multi-generation tracheobronchial conducting airway

    Energy Technology Data Exchange (ETDEWEB)

    Fan, B.; Cheng, Yung-Sung; Yeh, Hsu-Chi

    1995-12-01

    Knowledge of airflow patterns in the human lung is important for an analysis of lung diseases and drug delivery of aerosolized medicine for medical treatment. However, very little systematic information is available on the pattern of airflow in the lung and on how this pattern affects the deposition of toxicants in the lung, and the efficacy of aerosol drug therapy. Most previous studies have only considered the airflow through a single bifurcating airway. However, the flow in a network of more than one bifurcation is more complicated due to the effect of interrelated lung generations. Because of the variation of airway geometry and flow condition from generation to generation, a single bifurcating airway cannot be taken as a representative for the others in different generations. The flow in the network varies significantly with airway generations because of a redistribution of axial momentum by the secondary flow motions. The influence of the redistribution of flow is expected in every generation. Therefore, a systematic information of the airflow through a multi-generation tracheobronchial conducting airway is needed, and it becomes the purpose of this study. This study has provided information on airflow in a lung model which is necessary to the study of the deposition of toxicants and therapeutic aerosols.

  7. The efficacy of airflow and seat vibration on reducing visually induced motion sickness.

    Science.gov (United States)

    D'Amour, Sarah; Bos, Jelte E; Keshavarz, Behrang

    2017-06-20

    Visually induced motion sickness (VIMS) is a well-known sensation in virtual environments and simulators, typically characterized by a variety of symptoms such as pallor, sweating, dizziness, fatigue, and/or nausea. Numerous methods to reduce VIMS have been previously introduced; however, a reliable countermeasure is still missing. In the present study, the effect of airflow and seat vibration to alleviate VIMS was investigated. Eighty-two participants were randomly assigned to one of four groups (airflow, vibration, combined airflow and vibration, and control) and then exposed to a 15 min long video of a bicycle ride shot from first-person view. VIMS was measured using the Fast Motion Sickness Scale (FMS) and the Simulator Sickness Questionnaire (SSQ). Results showed that the exposure of airflow significantly reduced VIMS, whereas the presence of seat vibration, in contrast, did not have an impact on VIMS. Additionally, we found that females reported higher FMS scores than males, however, this sex difference was not found in the SSQ scores. Our findings demonstrate that airflow can be an effective and easy-to-apply technique to reduce VIMS in virtual environments and simulators, while vibration applied to the seat is not a successful method.

  8. Three-dimensional airflow and sediment transport patterns over barchan dunes

    Science.gov (United States)

    Smith, Alexander B.; Jackson, Derek W. T.; Cooper, J. Andrew G.

    2017-02-01

    Airflow dynamics and potential sediment transport were measured and modelled across various barchan dune topographies and incident wind conditions. Modification of near surface flow was recorded simultaneously in three dimensions (3D) using dense arrays of high-resolution 3D ultrasonic anemometers. In situ measurements provided rigorous validation and calibration for computational fluid dynamics (CFD) modelling. Measured and modelled results show good agreement between flow velocity, directionality, and turbulence intensity. Modelling of characteristic airflow conditions and surface shear stress beyond the instrument locations, elucidated airflow dynamics across the entire landform surface at an unprecedented level of detail. Emergent turbulent airflow patterns were identified in the form of two counter-rotating vortices that converge at the dune centreline downwind of the dune crest. Integrating a sediment transport function with CFD surface airflow allows for the spatial mapping of flux patterns across the entirety of the dune and interdune surface. On the stoss slope and laterally along the outer barchan arms, there is strong potential sediment flux in response to increased streamwise stress. In lee-side locations, sediment transport remains at 'above threshold' conditions and is redirected in response to complex turbulent vortices identified in the overlying wake zone. The precision of the models allows for the identification of complex flow perturbations and associated surface stresses that prove difficult to measure in the field. CFD in combination with a sediment transport function is demonstrated to be a useful tool in investigating morphodynamics of mobile dune systems.

  9. Reversible Computing

    Science.gov (United States)

    1980-02-01

    will have been introduced. 9. Reversible celular autemata We shall assume the reader to have some familiarity with the concept of cel- lular...10003 Mr. Kin B. Thcmpson 1 copy Technical Director Information Systems Divisia.i Naval Research Laboratory (OP-91T) Technical Information Division

  10. 公路改造工程中逆向物流网络结构优化研究%The Optimization of Reverse Logistics Network Structure in Highway Reconstruction Projects

    Institute of Scientific and Technical Information of China (English)

    胡云鹏

    2013-01-01

    实施公路工程逆向物流是发展循环经济和建立节约型生活的必然要求.本文结合道路工程废弃物回收的特点,建立了逆向物流网络,并运用双层规划模型实现了基于系统总成本最小的物流设施选址,最后结合公路改造工程中的具体案例验证了逆向物流网络设计的有效性.%The implementation of highway reverse logistics is an inevitable requirement for the development of the recycling economy and conservation-oriented society.In this paper,according to the characteristics of the road works waste recycling system,the author establishes a reverse logistics network and uses bilevel programming model to achieve a optimal facility location with minimum total system cost.Finally specific cases are used to verify the effectiveness of the reverse logistics network design.

  11. Airflow resistance measurement for a layer of granular material based on the Helmholtz resonance phenomenon.

    Science.gov (United States)

    Nishizu, Takahisa; Tomatsu, Eiji; Katsuno, Nakako

    2017-04-01

    A Helmholtz resonance technique was employed to predict the airflow resistance of layers of granular materials, namely glass beads, brown rice, soybean, adzuki beans, and corn kernels. Each granular sample was placed on the tube mouth of an open-type Helmholtz resonator. The resonant frequency was determined by measuring the electric impedance of a loudspeaker that was installed in the resonator and driven by a chirp signal linearly sweeping from 90 to 220 Hz for 6.0 s. For a changing sample layer thickness, the resonant frequency was measured, and the specific airflow resistance was calculated by measuring the static pressure drop required for N2 gas to flow through the layer at a constant velocity of 0.042 m/s. When the thickness of the layer was fixed, the Helmholtz resonant frequency decreased as the specific airflow resistance increased, regardless of the kind of granular material.

  12. Analyzing airflow in static ice caves by using the calcFLOW method

    Directory of Open Access Journals (Sweden)

    C. Meyer

    2015-09-01

    Full Text Available In this paper we present a method to detect airflow through ice caves and to quantify the corresponding airflow speeds by the use of temperature loggers. The time series of temperature observations at different loggers are cross-correlated. The time shift of best correlation corresponds to the travel time of the air and is used to derive the airflow speed between the loggers. We apply the method to test data observed inside Schellenberger Eishöhle (ice cave. The successful determination of airflow speeds depends on the existence of distinct temperature variations during the time span of interest. Moreover the airflow speed is assumed to be constant during the period used for the correlation analysis. Both requirements limit the applicability of the correlation analysis to determine instantaneous airflow speeds. Nevertheless the method is very helpful to characterize the general patterns of air movement and their slow temporal variations. The correlation analysis assumes a linear dependency between the correlated data. The good correlation we found for our test data confirms this assumption. We therefore in a second step estimate temperature biases and scale factors for the observed temperature variations by a least squares adjustment. The observed phenomena, a warming and a damping of temperature variations depending on the distance the air traveled inside the cave, are explained by a mixing of the inflowing air with the air inside the cave. Furthermore we test the significance of the determined parameters by a standard F test and study the sensitivity of the procedure to common manipulations of the original observations like smoothing. In the end we will give an outlook on possible applications and further development of this method.

  13. Numerical Simulations of Airflow and Droplet Dispersion in a Horizontal Ammonia Scrubber

    DEFF Research Database (Denmark)

    Liu, Li; Nielsen, Peter Vilhelm; Heiselberg, Per Kvols;

    2015-01-01

    Ammonia released in pig production industries can lead to eutrophication of surface waters, soil acidification, fertilization of vegetation and changes in ecosystems, etc. Air scrubbers with spray of aerosolized sulphur solution were used to remove the ammonia mixed in the airflow ventilated out......, and they were simulated by Eularian-Lagrangian method of Computation Fluid Dynamics (CFD). Realizable k-ε turbulence model were used to simulate airflow turbulence. Strong vortex rotating around the main stream direction were found along the scrubber. To weaken the vortex, the impact of adding a regulating...

  14. THEORETICAL ANALYSIS OF USING AIRFLOW TO PURGE RESIDUAL WATER IN AN INCLINED PIPE

    Institute of Scientific and Technical Information of China (English)

    SHEN Fang(沈芳); YAN Zong-yi(严宗毅); ZHAO Yao-hua(赵耀华); Kiyoshi Horii

    2002-01-01

    A refined theoretical analysis for using the spiral airflow and axial airflow to purge residual water in an inclined pipe was presented. The computations reveal that, in most cases, the spiral flow can purge the residual water in the inclined pipe indeed while the axial flow may induce back flow of the water, just as predicted in the experiments presented by Horii and Zhao et al. In addition, the effects of various initial conditions on water purging were studied in detail for both the spiral and axial flow cases.

  15. Coupled Outdoor and Indoor Airflow Prediction for Buildings Using Computational Fluid Dynamics (CFD

    Directory of Open Access Journals (Sweden)

    Deo Prasad

    2013-05-01

    Full Text Available The objective of this study is to investigate the accuracy of Computational Fluid Dynamics (CFD for simultaneously predicting the outdoor and indoor airflows of single-cell and multi-storey buildings. Empirical models and two existing wind tunnel experimental data are used for validation. This study found that coupled CFD simulations provide sufficiently accurate airflow predictions and, in cases of buildings with complex façade treatments, accurately accounts for changes in ventilation performance, which may be impossible using empirical models. This study concludes that coupled CFD simulations can generally be used to predict ventilation performance in small and large buildings.

  16. Occupational exposure to pesticides are associated with fixed airflow obstruction in middle-age.

    Science.gov (United States)

    Alif, Sheikh M; Dharmage, Shyamali C; Benke, Geza; Dennekamp, Martine; Burgess, John A; Perret, Jennifer L; Lodge, Caroline J; Morrison, Stephen; Johns, David Peter; Giles, Graham G; Gurrin, Lyle C; Thomas, Paul S; Hopper, John Llewelyn; Wood-Baker, Richard; Thompson, Bruce R; Feather, Iain H; Vermeulen, Roel; Kromhout, Hans; Walters, E Haydn; Abramson, Michael J; Matheson, Melanie Claire

    2017-07-07

    Population-based studies have found evidence of a relationship between occupational exposures and Chronic Obstructive Pulmonary Disease (COPD), but these studies are limited by the use of prebronchodilator spirometry. Establishing this link using postbronchodilator is critical, because occupational exposures are a modifiable risk factor for COPD. To investigate the associations between occupational exposures and fixed airflow obstruction using postbronchodilator spirometry. One thousand three hundred and thirty-five participants were included from 2002 to 2008 follow-up of the Tasmanian Longitudinal Health Study (TAHS). Spirometry was performed and lifetime work history calendars were used to collect occupational history. ALOHA plus Job Exposure Matrix was used to assign occupational exposure, and defined as ever exposed and cumulative exposure unit (EU)-years. Fixed airflow obstruction was defined by postbronchodilator FEV1/FVC exposure to biological dust (relative risk (RR)=1.58, 95% CI 1.01 to 2.48), pesticides (RR=1.74,95% CI 1.00 to 3.07) and herbicides (RR=2.09,95% CI 1.18 to 3.70) were associated with fixed airflow obstruction. Cumulative EU-years to all pesticides (RR=1.11,95% CI 1.00 to 1.25) and herbicides (RR=1.15,95% CI 1.00 to 1.32) were also associated with fixed airflow obstruction. In addition, all pesticides exposure was consistently associated with chronic bronchitis and symptoms that are consistent with airflow obstruction. Ever exposure to mineral dust, gases/fumes and vapours, gases, dust or fumes were only associated with fixed airflow obstruction in non-asthmatics only. Pesticides and herbicides exposures were associated with fixed airflow obstruction and chronic bronchitis. Biological dust exposure was also associated with fixed airflow obstruction in non-asthmatics. Minimising occupational exposure to these agents may help to reduce the burden of COPD. © Article author(s) (or their employer(s) unless otherwise stated in the text

  17. A Comparative Study of Airflow and Odorant Deposition in the Mammalian Nasal Cavity

    Science.gov (United States)

    Richter, Joseph; Rumple, Christopher; Ranslow, Allison; Quigley, Andrew; Pang, Benison; Neuberger, Thomas; Krane, Michael; van Valkenburgh, Blaire; Craven, Brent

    2013-11-01

    The complex structure of the mammalian nasal cavity provides a tortuous airflow path and a large surface area for respiratory air conditioning, filtering of inspired contaminants, and olfaction. Due to the small and contorted structure of the nasal turbinals, nasal anatomy and function remains poorly understood in most mammals. Here, we utilize high-resolution MRI scans to reconstruct anatomically-accurate models of the mammalian nasal cavity. These data are used to compare the form and function of the mammalian nose. High-fidelity computational fluid dynamics (CFD) simulations of nasal airflow and odorant deposition are presented and used to compare olfactory function across species (primate, rodent, canine, feline, ungulate).

  18. Effects of diffuser airflow minima on occupant comfort, air mixing, and building energy use (RP-1515)

    DEFF Research Database (Denmark)

    Arens, Edward; Zhang, Hui; Hoyt, Tyler

    2015-01-01

    There is great energy-saving potential in reducing variable air volume box minimum airflow set-points to about 10% of maximum. Typical savings are on the order of 10%-30% of total HVAC energy, remarkable for an inexpensive controls set-point change that properly maintains outside air ventilation...... comfort or air quality and that HVAC energy savings would be substantial. The hypotheses were almost entirely confirmed for both warm and cool seasons. But beyond this, the reduction of excess airflow during low-load periods caused occupants' cold discomfort in the warm season to be halved, a surprising...

  19. Two-dimensional airflow modeling underpredicts the wind velocity over dunes.

    Science.gov (United States)

    Michelsen, Britt; Strobl, Severin; Parteli, Eric J R; Pöschel, Thorsten

    2015-11-17

    We investigate the average turbulent wind field over a barchan dune by means of Computational Fluid Dynamics. We find that the fractional speed-up ratio of the wind velocity over the three-dimensional barchan shape differs from the one obtained from two-dimensional calculations of the airflow over the longitudinal cut along the dune's symmetry axis - that is, over the equivalent transverse dune of same size. This finding suggests that the modeling of the airflow over the central slice of barchan dunes is insufficient for the purpose of the quantitative description of barchan dune dynamics as three-dimensional flow effects cannot be neglected.

  20. Two-dimensional airflow modeling underpredicts the wind velocity over dunes

    OpenAIRE

    Britt Michelsen; Severin Strobl; Parteli, Eric J. R.; Thorsten Pöschel

    2015-01-01

    We investigate the average turbulent wind field over a barchan dune by means of Computational Fluid Dynamics. We find that the fractional speed-up ratio of the wind velocity over the three-dimensional barchan shape differs from the one obtained from two-dimensional calculations of the airflow over the longitudinal cut along the dune’s symmetry axis — that is, over the equivalent transverse dune of same size. This finding suggests that the modeling of the airflow over the central slice of barc...

  1. 42 CFR 84.153 - Airflow resistance test, Type A and Type AE supplied-air respirators; minimum requirements.

    Science.gov (United States)

    2010-10-01

    ... supplied-air respirators; minimum requirements. 84.153 Section 84.153 Public Health PUBLIC HEALTH SERVICE... APPROVAL OF RESPIRATORY PROTECTIVE DEVICES Supplied-Air Respirators § 84.153 Airflow resistance test, Type A and Type AE supplied-air respirators; minimum requirements. (a) Airflow resistance will...

  2. 42 CFR 84.154 - Airflow resistance test; Type B and Type BE supplied-air respirators; minimum requirements.

    Science.gov (United States)

    2010-10-01

    ... supplied-air respirators; minimum requirements. 84.154 Section 84.154 Public Health PUBLIC HEALTH SERVICE... APPROVAL OF RESPIRATORY PROTECTIVE DEVICES Supplied-Air Respirators § 84.154 Airflow resistance test; Type B and Type BE supplied-air respirators; minimum requirements. (a) Airflow resistance shall...

  3. 涡轮增压器废气旁通换向电磁阀优化设计与分析%The turbocharger exhaust bypassthe reversing solenoid valve optimization design and analysis

    Institute of Scientific and Technical Information of China (English)

    胡子健; 张兴娇

    2016-01-01

    本文以涡轮增压器中的废气旁通换向电磁阀为例,对该电磁阀的优化设计问题进行了分析,首先对废气旁通换向电磁阀进行了概述,继而从整体设计以及电磁铁的优化设计两个角度对其优化设计过程进行了讨论,最后研究了其在未来的发展方向,目的在于使其在应用过程中存在的问题能够被有效的解决,达到增加发动机输出功率的目的,为涡轮增压器性能的改善带来更大的价值.%In this paper,based on the exhaust turbocharger bypass the reversing solenoid valve as an example,the optimization of the electromagnetic valve design problems are analyzed,and the first to exhaust bypass the reversing solenoid valve were summarized, and then from the overall design and the optimal design of the electromagnet two angles for the optimization design process are discussed,finally studied the direction of development in the future,the purpose is to make it in the application process, the problems can be resolved effectively achieve the purpose of increase engine power output,to improve the performance of the turbocharger to bring more value

  4. Experimental and modelling study of the effect of airflow orientation with respect to strip electrode on ozone production of surface dielectric barrier discharge

    Science.gov (United States)

    Mikeš, J.; Pekárek, S.; Soukup, I.

    2016-11-01

    This study examines the effect of airflow orientation with respect to the strip active electrode on concentration of ozone and nitrogen dioxide produced in a planar generator based on the surface dielectric barrier discharge. The orientation of the airflow was tested in parallel and perpendicular with respect to the strips. It was found that in the investigated range of average discharge power, the ozone concentration increases approximately by 25% when airflow was oriented in parallel with respect to the strips in comparison with perpendicular orientation of the airflow. Similarly the increase of nitrogen dioxide concentration was observed for parallel orientation of the airflow with respect to the strips in comparison with the perpendicular orientation of the airflow. Within the range of wavelengths from 250 to 1100 nm, the changes of intensities of spectral lines associated with airflow orientation have been observed. A 3D numerical model describing ion trajectories and airflow patterns have also been developed.

  5. 空气反循环钻头井底流场分析及结构优化%Analysis on the Bottomhole Flow Field and Structural Optimization of Air Reverse Circulation Drill Bit

    Institute of Scientific and Technical Information of China (English)

    甘心; 殷琨; 殷其雷; 李鹏

    2016-01-01

    In order to improve the application effect of the reverse circulation air hammer drilling technique,on the construction of rock-socketed pile by using software Fluent,the authors analyzed the horizontal inclination angleθd of flushing nozzles and horizontal inclination angleθk of pressure-restoring grooves on the reverse circulation drill bit used in the construction of rock-socketed pile.The effects of theθd of flushing nozzles and theθk of pressure-restoring grooves on the suction coefficient ω of reverse circulation drill bit are obtained.Meanwhile,aiming at the deficiency in the structure design of central hollow-through hole on the reverse circulation drill bit,we optimized the structure of reverse circulation drill bit;and thereby,the suction capacity is obviously enhanced.A 660 mm reverse circulation drill bit adopted to the optimized structure is processed,and the field tests are carried out.It can be concluded from the test results that the effect of reverse circulation formation is good,the average penetration rate is 6.00 m/h, the surface of weakly weathered rocks is successfully drilled out. This meets the requirements on drilling out the surface of weakly weathered rocks and stability of borehole wall without borehole collapse.%为改善空气潜孔锤反循环钻进技术在大口径嵌岩桩施工中的应用效果,运用 Fluent 软件对嵌岩桩施工用反循环钻头底喷孔水平倾角θd 和扩压槽水平倾角θk 做了进一步的分析和研究,得到θd 和θk 对反循环钻头抽吸系数ω的影响规律。在分析中发现原有反循环钻头中心贯通孔结构设计中的不足之处,并进行了优化,优化后的反循环钻头抽吸效果明显增强。采用优化后的结构加工了一个直径为660 mm 的反循环钻头,并进行现场钻进试验,试验效果良好,平均钻进效率为6.00 m/h,成功嵌入微风化岩层表面,能够满足嵌岩桩施工对嵌入微风化岩层和孔壁稳定、无塌孔的要求。

  6. Improvement and optimization of a multiplex real-time reverse transcription polymerase chain reaction assay for the detection and typing of Vesicular stomatitis virus.

    Science.gov (United States)

    Hole, Kate; Velazquez-Salinas, Lauro; Velazques-Salinas, Lauro; Clavijo, Alfonso

    2010-05-01

    An improvement to a previously reported real-time reverse transcription polymerase chain reaction (real-time RT-PCR) assay for the detection of Vesicular stomatitis virus (VSV) is described. Results indicate that the new assay is capable of detecting a panel of genetically representative strains of VSV present in North, Central, and South America. The assay is specific for VSV and allows for simultaneous differentiation between Vesicular stomatitis Indiana virus and Vesicular stomatitis New Jersey virus. This real-time RT-PCR is able to detect current circulating strains of VSV and can be used for rapid diagnosis of VSV and differentiation of VSV from other vesicular diseases, such as foot-and-mouth disease.

  7. Optimization of rapid Salmonella enterica detection in liquid whole eggs by SYBR green I-based real-time reverse transcriptase-polymerase chain reaction.

    Science.gov (United States)

    Techathuvanan, Chayapa; D'Souza, Doris Helen

    2011-04-01

    Eggs and egg products have a high risk of Salmonella enterica serovar Enteritidis contamination leading to gastroenteritis outbreaks in humans. Thus, a rapid screening tool for viable Salmonella Enteritidis cells in the egg industry is needed. Our objective was to rapidly and sensitively detect viable Salmonella Enteritidis from spiked liquid whole eggs (LWEs) within 24 h using SYBR green I-based real-time reverse transcriptase-polymerase chain reaction (PCR) targeting the Salmonella specific invA gene along with an internal amplification control in a Bio-Rad iCycler. LWE was inoculated with Salmonella Enteritidis and mixed with tetrathionate broth, and 100 μL of serially diluted portions in phosphate-buffered saline was plated on Xylose Lysine Tergitol 4 agar or 5 mL were used for RNA extraction by the TRIzol method immediately or after enrichment of 6, 12, or 16 h at 37 °C. The real-time reverse transcriptase-PCR assay was carried out using previously described Salmonella invA gene primers. Melt temperature analysis of the PCR product was included to determine specific invA amplification. Without enrichment, the assay detection limit was 10(7) colony forming units (CFU)/25 mL LWE. After enrichment for 6 and 12 h, Salmonella Enteritidis could be detected from LWE up to 10(4) and 10(2) CFU/25 mL, respectively. Improved Salmonella Enteritidis detection up to 10(0) CFU/25 mL was obtained after 16-h enrichment. Even with 16-h enrichment, the results could be still be obtained within 24 h, which is much faster than by traditional cultural detection that takes several days. Therefore, this assay appears suitable for routine detection of Salmonella enterica contamination by the egg industry to help prevent the transmission of egg-associated Salmonella outbreaks and timely recall of contaminated products.

  8. Experimental investigation of transient thermal behavior of an airship under different solar radiation and airflow conditions

    Science.gov (United States)

    Li, De-Fu; Xia, Xin-Lin; Sun, Chuang

    2014-03-01

    Knowledge of the thermal behavior of airships is crucial to the development of airship technology. An experiment apparatus is constructed to investigate the thermal response characteristics of airships, and the transient temperature distributions of both hull and inner gas are obtained under the irradiation of a solar simulator and various airflow conditions. In the course of the research, the transient temperature change of the experimental airship is measured for four airflow speeds of 0 m/s (natural convection), 3.26 m/s, 5.5 m/s and 7.0 m/s, and two incident solar radiation values of 842.4 W/m2 and 972.0 W/m2. The results show that solar irradiation has significant influence on the airship hull and inner gas temperatures even if the airship stays in a ground airflow environment where the heat transfer is dominated by radiation and convection. The airflow around the airship is conducive to reduce the hull temperature and temperature nonuniformity. Transient thermal response of airships rapidly varies with time under solar radiation conditions and the hull temperature remains approximately constant in ˜5-10 min. Finally, a transient thermal model of airship is developed and the model is validated through comparison with the experimental data.

  9. Investigation of airflow patterns in a microclimate by particle image velocimetry (PIV)

    DEFF Research Database (Denmark)

    Mortensen, Lone Hedegaard; Rode, Carsten; Peuhkuri, Ruut

    2008-01-01

    moisture production. The lack of air circulation decreases the surface temperature, which can cause problems. A particle image velocimetry (PIV) investigation was performed of the airflow patterns in such a microclimate. This paper describes the experimental set-up and the results. The results indicate...

  10. Investigation of Airflow in a Room with displacement ventilation by means of a CFD-model

    DEFF Research Database (Denmark)

    Jacobsen, T. V.; Nielsen, Peter Vilhelm

    The airflow in front of an inlet device in a room with displacement ventilation is investigated in this study. In continuation of the full-scale measurements and the development of a CFD-model, described in /1/, this report aims at testing the model and conducting numerical experiments to provide...

  11. Airflow limitation in asthmatic children assessed with a non-invasive EMG technique

    NARCIS (Netherlands)

    Maarsingh, EJW; van Eykern, LA; de Haan, RJ; Griffioen, RW; Hoekstra, MO; van Aalderen, WMC

    2002-01-01

    The aim of the study was to investigate the association between electromyography (EMG) of the diaphragm and intercostal muscles and the forced expiratory volume in 1 s (FEV1) at different levels of histamine-induced airflow limitation, and the response to salbutamol. Moreover, we assessed the reprod

  12. Altered nasal airflow : an unusual complication following implant surgery in the anterior maxilla

    NARCIS (Netherlands)

    Wolff, J.; Karagozoglu, K.H.; Bretschneider, J.H.; Forouzanfar, T.; Schulten, E.A.J.M.

    2016-01-01

    Dental implants have been in routine clinical use for over three decades and are a predictable treatment modality. However, as with all other aspects of dentistry, complications occur. A 50-year-old female patient with complaints of a long ongoing unpleasant altered nasal airflow presented herself a

  13. Underestimation of airflow obstruction among young adults using FEV(1)/FVC

    NARCIS (Netherlands)

    Cerveri, I.; Corsico, A. G.; Accordini, S.; Niniano, R.; Ansaldo, E.; Anto, J. M.; Kunzli, N.; Janson, C.; Sunyer, J.; Jarvis, D.; Svanes, C.; Gislason, T.; Heinrich, J.; Schouten, J. P.; Wjst, M.; Burney, P.; de Marco, R.

    2008-01-01

    Background: Early detection of airflow obstruction is particularly important among young adults because they are more likely to benefit from intervention. Using the forced expiratory volume in 1 s (FEV(1)) to forced vital capacity (FVC) (FEV(1)/FVC) Methods: To evaluate the characteristics and longi

  14. Airflow resistance of heat and moisture exchange filters with and without a tracheostoma valve

    NARCIS (Netherlands)

    Verkerke, GJ; Geertsema, AA; Schutte, HK

    2002-01-01

    Rehabilitation of laryngectomees has been furthered by the introduction of heat and moisture exchange (HME) filters, placed over a tracheostoma or on a tracheostoma valve (TSV). The airflow resistance of HME filters is an important factor with regard to the comfort of the patient. The goal of this s

  15. ENVIRONMENTAL TECHNOLOGY VERIFICATION, TEST REPORT OF CONTROL OF BIOAEROSOLS IN HVAC SYSTEMS, AIRFLOW PRODUCTS AFP30

    Science.gov (United States)

    The Environmental Technology Verification report discusses the technology and performance of the AFP30 air filter for dust and bioaerosol filtration manufactured by Airflow Products. The pressure drop across the filter was 62 Pa clean and 247 Pa dust loaded. The filtration effici...

  16. Computational and experimental study of airflow around a fan powered UVGI lamp

    Science.gov (United States)

    Kaligotla, Srikar; Tavakoli, Behtash; Glauser, Mark; Ahmadi, Goodarz

    2011-11-01

    The quality of indoor air environment is very important for improving the health of occupants and reducing personal exposure to hazardous pollutants. An effective way of controlling air quality is by eliminating the airborne bacteria and viruses or by reducing their emissions. Ultraviolet Germicidal Irradiation (UVGI) lamps can effectively reduce these bio-contaminants in an indoor environment, but the efficiency of these systems depends on airflow in and around the device. UVGI lamps would not be as effective in stagnant environments as they would be when the moving air brings the bio-contaminant in their irradiation region. Introducing a fan into the UVGI system would augment the efficiency of the system's kill rate. Airflows in ventilated spaces are quite complex due to the vast range of length and velocity scales. The purpose of this research is to study these complex airflows using CFD techniques and validate computational model with airflow measurements around the device using Particle Image Velocimetry measurements. The experimental results including mean velocities, length scales and RMS values of fluctuating velocities are used in the CFD validation. Comparison of these data at different locations around the device with the CFD model predictions are performed and good agreement was observed.

  17. Air-flow resistances of silicone rubber voice prostheses after formation of bacterial and fungal biofilms

    NARCIS (Netherlands)

    Elving, GJ; van der Mei, HC; Busscher, HJ; van Weissenbruch, R; Albers, FWJ

    Laryngectomized patients use silicone rubber voice prostheses to rehabilitate their voice. However, biofilm formation limits the lifetime of voice prostheses by causing leakage or an increased air-flow resistance and the prosthesis has to be replaced. To determine which bacterial or yeast strains,

  18. Experimental study on airflow fluctuation characteristic of an underfloor air supply terminal unit

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Jinping [School of Electric Power, South China University of Technology, Guangzhou 510640 (China); State Key Laboratory of Subtropical Building Science, South China University of Technology, Guangzhou 510640 (China); Wu, Yanfang [Design Institute of Guangzhou Metro Corporation, Guangzhou 510010 (China)

    2010-11-15

    In order to investigate dynamic characteristic of underfloor air supply terminal unit, an IFV900A hot-wire anemometer was used to measure the corresponding velocity field. Turbulence intensity and power spectrum density exponent of air velocity signal were analyzed. The result showed that the outlet velocity distribution of underfloor air supply terminal unit was uniform. With increment of height, the velocity distribution trends to be uniform. Two velocity attenuation regions appear during airflow development. Turbulence intensity changes obviously with height. It is lower than that of mechanical wind. Turbulence intensity goes up with the increment of jetting distance. Power spectrum density exponent trends to the value of natural wind with increase of jetting distance and decrease of wind velocity. The exponent value approaches to the value of typical natural wind for the air velocity is 0.5 m/s under high supply air rate. With airflow diffusion, the fluctuation characteristic of airflow varies obviously with the jetting direction. The fluctuation characteristic of airflow changes to that of natural wind with the increase of height which can improve comfort of indoor environment. (author)

  19. Effects of differences in nasal anatomy on airflow distribution: a comparison of four individuals at rest.

    Science.gov (United States)

    Segal, Rebecca A; Kepler, Grace M; Kimbell, Julia S

    2008-11-01

    Differences in nasal anatomy among human subjects may cause significant differences in respiratory airflow patterns and subsequent dosimetry of inhaled gases and particles in the respiratory tract. This study used computational fluid dynamics (CFD) to study inter-individual differences in nasal airflow among four healthy individuals. Magnetic resonance imaging (MRI) scans were digitized and nasal-surface-area-to-volume ratios (SAVR) were calculated for 15 adults. Two males and two females, representative of the range of SAVR values, were selected for flow analysis. Nasal CFD models were constructed for each subject by a semi-automated process that provided input to a commercial mesh generator to generate structured hexahedral meshes (Gambit, Fluent, Inc., Lebanon, NH, USA). Steady-state inspiratory laminar airflow at 15 L/min was calculated using commercial CFD software (FIDAP, Fluent, Inc., Lebanon, NH, USA). Streamline patterns, velocities, and helicity values were compared. In all subjects, the majority of flow passed through the middle and ventral regions of the nasal passages; however, the amount and location of swirling flow differed among individuals. Cross-sectional flow allocation analysis also indicated inter-individual differences. Laboratory water-dye experiments confirmed streamlines and velocity magnitudes predicted by the computational model. These results suggest that significant inter-individual differences exist in bulk airflow patterns in the nose.

  20. Airflow visualization in a model of human glottis near the self-oscillating vocal folds model

    Directory of Open Access Journals (Sweden)

    Horáček J.

    2011-06-01

    Full Text Available The contribution describes PIV (Particle Image Velocimetry measurement of airflow in the glottal region of complex physical models of the voice production that consist of 1 : 1 scaled models of the trachea, the self-oscillating vocal folds and the human vocal tract with acoustical spaces that correspond to the vowels /a:/, /u:/ and /i:/. The time-resolved PIV method was used for visualization of the airflow simultaneously with measurements of subglottal pressure, radiated acoustic pressure and vocal fold vibrations. The measurements were performed within a physiologically real range of mean airflow rate and fundamental phonation frequency. The images of the vibrating vocal folds during one oscillation period were recorded by the high-speed camera at the same time instants as the velocity fields measured by the PIV method.In the region above the models of the ventricular folds and of the epilaryngeal tube it is possible to detect large vortices with dimensions comparable with the channel cross-section and moving relatively slowly downstream. The vortices disappear in the narrower pharyngeal part of the vocal tract model where the flow is getting more uniform. The basic features of the coherent structures identified in the laryngeal cavity models in the interval of the measured airflow rates were found qualitatively similar for all three vowels investigated.

  1. Comparison of turbulence models for numerical calculation of airflow in an annex 20 room

    DEFF Research Database (Denmark)

    Voigt, Lars P. K.

    2000-01-01

    The report deals with 2-D numerical calculation of room airflow in an isothermal annex 20 room. The report documents the ability of the flow solver EllipSys2D to give results in good agreement with measurements for the specified test case. The flow solver is a finite volume code solving...

  2. Fixed airflow obstruction in asthma: a descriptive study of patient profiles and effect on treatment responses

    OpenAIRE

    Tashkin, Donald P.; Chipps, Bradley E.; Trudo,Frank; Zangrilli, James G

    2014-01-01

    Background The role of fixed airflow obstruction (FAO) in asthma is unclear. Objective: To assess the relationship between FAO and clinical features of asthma and the effect of FAO on treatment response. Methods: Post hoc descriptive analysis of data stratified by FAO category (screening post-albuterol FEV1/FVC

  3. Test-Retest Reliability of Respiratory Resistance Measured with the Airflow Perturbation Device

    Science.gov (United States)

    Gallena, Sally K.; Solomon, Nancy Pearl; Johnson, Arthur T.; Vossoughi, Jafar; Tian, Wei

    2014-01-01

    Purpose: In this study, the authors aimed to determine reliability of the airflow perturbation device (APD) to measure respiratory resistance within and across sessions during resting tidal (RTB) and postexercise breathing in healthy athletes, and during RTB across trials within a session in athletes with paradoxical vocal fold motion (PVFM)…

  4. Evaluation of Sub-Zonal Airflow Models for the Prediction of Local Interior Boundary Conditions

    DEFF Research Database (Denmark)

    Steskens, Paul W. M. H.; Janssen, Hans; Rode, Carsten

    2013-01-01

    and applicability of the sub-zonal airflow model to predict the local indoor environmental conditions, as well as the local surface transfer coefficients near building components. Two test cases were analyzed for, respectively, natural and forced convection in a room. The simulation results predicted from the sub...

  5. Airflow limitation in asthmatic children assessed with a non-invasive EMG technique

    NARCIS (Netherlands)

    Maarsingh, EJW; van Eykern, LA; de Haan, RJ; Griffioen, RW; Hoekstra, MO; van Aalderen, WMC

    2002-01-01

    The aim of the study was to investigate the association between electromyography (EMG) of the diaphragm and intercostal muscles and the forced expiratory volume in 1 s (FEV1) at different levels of histamine-induced airflow limitation, and the response to salbutamol. Moreover, we assessed the

  6. Strongly coupled interaction between a ridge of fluid and an inviscid airflow

    KAUST Repository

    Paterson, C.

    2015-07-01

    © 2015 AIP Publishing LLC. The behaviour of a steady thin sessile or pendent ridge of fluid on an inclined planar substrate which is strongly coupled to the external pressure gradient arising from an inviscid airflow parallel to the substrate far from the ridge is described. When the substrate is nearly horizontal, a very wide ridge can be supported against gravity by capillary and/or external pressure forces; otherwise, only a narrower (but still wide) ridge can be supported. Classical thin-aerofoil theory is adapted to obtain the governing singular integro-differential equation for the profile of the ridge in each case. Attention is focused mainly on the case of a very wide sessile ridge. The effect of strengthening the airflow is to push a pinned ridge down near to its edges and to pull it up near to its middle. At a critical airflow strength, the upslope contact angle reaches the receding contact angle at which the upslope contact line de-pins, and continuing to increase the airflow strength beyond this critical value results in the de-pinned ridge becoming narrower, thicker, and closer to being symmetric in the limit of a strong airflow. The effect of tilting the substrate is to skew a pinned ridge in the downslope direction. Depending on the values of the advancing and receding contact angles, the ridge may first de-pin at either the upslope or the downslope contact line but, in general, eventually both contact lines de-pin. The special cases in which only one of the contact lines de-pins are also considered. It is also shown that the behaviour of a very wide pendent ridge is qualitatively similar to that of a very wide sessile ridge, while the important qualitative difference between the behaviour of a very wide ridge and a narrower ridge is that, in general, for the latter one or both of the contact lines may never de-pin.

  7. Improving aviation safety with information visualization: Airflow hazard display for helicopter pilots

    Science.gov (United States)

    Aragon, Cecilia Rodriguez

    Many aircraft accidents each year are caused by encounters with airflow hazards near the ground, such as vortices or other turbulence. While such hazards frequently pose problems to fixed-wing aircraft, they are especially dangerous to helicopters, whose pilots often have to operate into confined areas or under operationally stressful conditions. Pilots are often unaware of these invisible hazards while simultaneously attending to other aspects of aircraft operation close to the ground. Recent advances in aviation sensor technology offer the potential for aircraft-based sensors that can gather large amounts of airflow velocity data in real time. This development is likely to lead to the production of onboard detection systems that can convey detailed, specific information about imminent airflow hazards to pilots. A user interface is required that can present extensive amounts of data to the pilot in a useful manner in real time, yet not distract from the pilot's primary task of flying the aircraft. In this dissertation, we address the question of how best to present safety-critical visual information to a cognitively overloaded user in real time. We designed an airflow hazard visualization system according to user-centered design principles, implemented the system in a high fidelity, aerodynamically realistic rotorcraft flight simulator, and evaluated it via usability studies with experienced military and civilian helicopter pilots. We gathered both subjective data from the pilots' evaluations of the visualizations, and objective data from the pilots' performance during the landing simulations. Our study demonstrated that information visualization of airflow hazards, when presented to helicopter pilots in the simulator, dramatically improved their ability to land safely under turbulent conditions. Although we focused on one particular aviation application, the results may be relevant to user interfaces and information visualization in other safety

  8. Measured Performance of a Varied Airflow Small-Diameter Duct System

    Energy Technology Data Exchange (ETDEWEB)

    Poerschke, Andrew [IBACOS, Inc., Pittsburgh, PA (United States)

    2017-03-16

    This study tests the performance of a variable airflow small-diameter duct heating, ventilation, and air conditioning (HVAC) system in a new construction unoccupied low-load test house in Pittsburgh, Pennsylvania. The duct system was installed entirely in conditioned space and was operated from the winter through summer seasons. Measurements were collected on the in-room temperatures and energy consumed by the air handler and heat pump unit. Operation modes with three different volumes of airflow were compared to determine the ideal airflow scenario that maximizes room-to-room thermal uniformity while minimizing fan energy consumption. Black felt infrared imagery was used as a measure of diffuser throw and in-room air mixing. Measured results indicate the small-diameter, high velocity airflow system can provide comfort under some conditions. Solar heat gains resulted in southern rooms drifting beyond acceptable temperature limits. Insufficient airflow to some bedrooms also resulted in periods of potential discomfort. Homebuilders or HVAC contractors can use these results to assess whether this space conditioning strategy is an attractive alternative to a traditional duct system. The team performed a cost analysis of two duct system configurations: (1) a conventional diameter and velocity duct system, and (2) the small-diameter duct system. This work applies to both new and retrofit homes that have achieved a low heating and cooling density either by energy conservation or by operation in a mild climate with few heating or cooling degree days. Guidance is provided on cost trade-offs between the conventional duct system and the small-diameter duct system.

  9. Measured Performance of a Varied Airflow Small-Diameter Duct System

    Energy Technology Data Exchange (ETDEWEB)

    Poerschke, Andrew [IBACOS, Inc., Pittsburgh, PA (United States)

    2017-03-01

    This study tests the performance of a variable airflow small-diameter duct heating, ventilation, and air conditioning (HVAC) system in a new construction unoccupied low-load test house in Pittsburgh, Pennsylvania. The duct system was installed entirely in conditioned space and was operated from the winter through summer seasons. Measurements were collected on the in-room temperatures and energy consumed by the air handler and heat pump unit. Operation modes with three different volumes of airflow were compared to determine the ideal airflow scenario that maximizes room-to-room thermal uniformity while minimizing fan energy consumption. Black felt infrared imagery was used as a measure of diffuser throw and in-room air mixing. Measured results indicate the small-diameter, high velocity airflow system can provide comfort under some conditions. Solar heat gains resulted in southern rooms drifting beyond acceptable temperature limits. Insufficient airflow to some bedrooms also resulted in periods of potential discomfort. Homebuilders or HVAC contractors can use these results to assess whether this space conditioning strategy is an attractive alternative to a traditional duct system. The team performed a cost analysis of two duct system configurations: (1) a conventional diameter and velocity duct system, and (2) the small-diameter duct system. This work applies to both new and retrofit homes that have achieved a low heating and cooling density either by energy conservation or by operation in a mild climate with few heating or cooling degree days. Guidance is provided on cost trade-offs between the conventional duct system and the small-diameter duct system.

  10. Strongly coupled interaction between a ridge of fluid and an inviscid airflow

    Science.gov (United States)

    Paterson, C.; Wilson, S. K.; Duffy, B. R.

    2015-07-01

    The behaviour of a steady thin sessile or pendent ridge of fluid on an inclined planar substrate which is strongly coupled to the external pressure gradient arising from an inviscid airflow parallel to the substrate far from the ridge is described. When the substrate is nearly horizontal, a very wide ridge can be supported against gravity by capillary and/or external pressure forces; otherwise, only a narrower (but still wide) ridge can be supported. Classical thin-aerofoil theory is adapted to obtain the governing singular integro-differential equation for the profile of the ridge in each case. Attention is focused mainly on the case of a very wide sessile ridge. The effect of strengthening the airflow is to push a pinned ridge down near to its edges and to pull it up near to its middle. At a critical airflow strength, the upslope contact angle reaches the receding contact angle at which the upslope contact line de-pins, and continuing to increase the airflow strength beyond this critical value results in the de-pinned ridge becoming narrower, thicker, and closer to being symmetric in the limit of a strong airflow. The effect of tilting the substrate is to skew a pinned ridge in the downslope direction. Depending on the values of the advancing and receding contact angles, the ridge may first de-pin at either the upslope or the downslope contact line but, in general, eventually both contact lines de-pin. The special cases in which only one of the contact lines de-pins are also considered. It is also shown that the behaviour of a very wide pendent ridge is qualitatively similar to that of a very wide sessile ridge, while the important qualitative difference between the behaviour of a very wide ridge and a narrower ridge is that, in general, for the latter one or both of the contact lines may never de-pin.

  11. Pulmonary anatomy in the Nile crocodile and the evolution of unidirectional airflow in Archosauria

    Directory of Open Access Journals (Sweden)

    Emma R. Schachner

    2013-03-01

    Full Text Available The lungs of birds have long been known to move air in only one direction during both inspiration and expiration through most of the tubular gas-exchanging bronchi (parabronchi. Recently a similar pattern of airflow has been observed in American alligators, a sister taxon to birds. The pattern of flow appears to be due to the arrangement of the primary and secondary bronchi, which, via their branching angles, generate inspiratory and expiratory aerodynamic valves. Both the anatomical similarity of the avian and alligator lung and the similarity in the patterns of airflow raise the possibility that these features are plesiomorphic for Archosauria and therefore did not evolve in response to selection for flapping flight or an endothermic metabolism, as has been generally assumed. To further test the hypothesis that unidirectional airflow is ancestral for Archosauria, we measured airflow in the lungs of the Nile crocodile (Crocodylus niloticus. As in birds and alligators, air flows cranially to caudally in the cervical ventral bronchus, and caudally to cranially in the dorsobronchi in the lungs of Nile crocodiles. We also visualized the gross anatomy of the primary, secondary and tertiary pulmonary bronchi of C. niloticus using computed tomography (CT and microCT. The cervical ventral bronchus, cranial dorsobronchi and cranial medial bronchi display similar characteristics to their proposed homologues in the alligator, while there is considerable variation in the tertiary and caudal group bronchi. Our data indicate that the aspects of the crocodilian bronchial tree that maintain the aerodynamic valves and thus generate unidirectional airflow, are ancestral for Archosauria.

  12. Optimization of UV LED-Curable Ink for Reverse-Offset Roll-to-Plate (RO-R2P) Printing

    Science.gov (United States)

    Mendoza, Kayna Lee; Ortega, Ada; Kim, Nam Soo

    2015-03-01

    Reverse-offset roll-to-plate printing has become increasingly popular in the printing industry because of the ease with which the printing process can be manipulated to achieve a high-resolution pattern with line widths as narrow as 5 μm with precision and accuracy. The printing procedure involves three stages, and a roller is required to transfer ink from each stage. The substrates used throughout this experiment were chosen by measuring their contact angles ( θ) and using them in accordance with the sequence: θ (Stage 1) > θ (roller) > θ (Stage 2) and θ (Stage 3). An ultraviolet (UV) light-emitting diode (LED)-curable ink was used during the printing process; however, the pristine solution of this ink was unsuitable for printing a final pattern on the substrate because of its viscosity. Diluting the solution of the UV LED-curable ink with 40% CH3OH resulted in reduced viscosity. The original solution had a viscosity of approximately 40.7 cP whereas that of the diluted solution was approximately 25 cP. The two solutions behaved as non-Newtonian, dilatant, shear-thickening fluids. The UV LED-curable ink solutions, both dilute and non-dilute, were successfully printed by use of an inkjet printer and three-dimensional printing methods.

  13. Aberrant Glycosylation of Anchor-Optimized MUC1 Peptides Can Enhance Antigen Binding Affinity and Reverse Tolerance to Cytotoxic T Lymphocytes

    Directory of Open Access Journals (Sweden)

    Latha B. Pathangey

    2016-06-01

    Full Text Available Cancer vaccines have often failed to live up to their promise, although recent results with checkpoint inhibitors are reviving hopes that they will soon fulfill their promise. Although mutation-specific vaccines are under development, there is still high interest in an off-the-shelf vaccine to a ubiquitous antigen, such as MUC1, which is aberrantly expressed on most solid and many hematological tumors, including more than 90% of breast carcinomas. Clinical trials for MUC1 have shown variable success, likely because of immunological tolerance to a self-antigen and to poor immunogenicity of tandem repeat peptides. We hypothesized that MUC1 peptides could be optimized, relying on heteroclitic optimizations of potential anchor amino acids with and without tumor-specific glycosylation of the peptides. We have identified novel MUC1 class I peptides that bind to HLA-A*0201 molecules with significantly higher affinity and function than the native MUC1 peptides. These peptides elicited CTLs from normal donors, as well as breast cancer patients, which were highly effective in killing MUC1-expressing MCF-7 breast cancer cells. Each peptide elicited lytic responses in greater than 6/8 of normal individuals and 3/3 breast cancer patients. The CTLs generated against the glycosylated-anchor modified peptides cross reacted with the native MUC1 peptide, STAPPVHNV, suggesting these analog peptides may offer substantial improvement in the design of epitope-based vaccines.

  14. A pH and solvent optimized reverse-phase ion-paring-LC–MS/MS method that leverages multiple scan-types for targeted absolute quantification of intracellular metabolites

    DEFF Research Database (Denmark)

    McCloskey, Douglas; Gangoiti, Jon A.; Palsson, Bernhard O.;

    2015-01-01

    to the understanding of intracellular metabolism. Liquid chromatography coupled to mass spectrometry (LC–MS and LC–MS/MS) has become a reliable means with which to quantify a multitude of intracellular metabolites in parallel with great specificity and accuracy. This work details a method that builds and extends upon...... existing reverse phase ion-paring liquid chromatography methods for separation and detection of polar and anionic compounds that comprise key nodes of intracellular metabolism by optimizing pH and solvent composition. In addition, the presented method utilizes multiple scan types provided by hybrid...... instrumentation to improve confidence in compound identification. The developed method was validated for a broad coverage of polar and anionic metabolites of intracellular metabolism...

  15. 基于遗传优化模型反向法变极的求解与算法%The Solution of Reverse-Current Pole-Changing and Its Algorithm Based on GA Optimization Model

    Institute of Scientific and Technical Information of China (English)

    于克训; 刘小洪

    2000-01-01

    The solution and algorithm of reverse-current pole-changing on the symmetrical block diagram and GA optimizing model are developed. The detailed mathematical flow is also presented with the corresponding computer software. The computer automation is realized in pole-changing winding design. Its practicability and advantages are proved in the example given.%基于变极绕组设计的对称块图法和遗传优化算法反向法变极的数学模型,提出了具体的求解方法及算法,给出了详细的计算流程图,研制了相应的计算机软件,实现了变极绕组设计的计算机自动化,实例证明了理论及方法的实用性及先进性.

  16. 基于环境会计的逆向物流成本收益优化%Optimization of Reverse Logistics Cost and Revenue Based on Environment Accounting

    Institute of Scientific and Technical Information of China (English)

    赵淑红

    2014-01-01

    In this paper, we analyzed the importance of reverse logistics, summarized the shortcomings in the cost in and revenue from the reverse logistics process of the Chinese enterprises, then presented the strategy to optimize the cost and revenue on the basis of environment accounting, and at the end, proposed the corresponding solutions from the perspective of the government and enterprise.%分析了逆向物流的重要性,总结了我国企业目前在逆向物流成本及收益核算方面存在的弊端,从环境会计与逆向物流两个角度出发,给出了以环境会计为基础的逆向物流成本收益最大化策略,此外,从政府与公司的视角出发,给出了对应的解决办法。

  17. 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...

  18. Genome-wide linkage analysis of severe, early-onset chronic obstructive pulmonary disease: airflow obstruction and chronic bronchitis phenotypes.

    Science.gov (United States)

    Silverman, Edwin K; Mosley, Jonathan D; Palmer, Lyle J; Barth, Matthew; Senter, Jody M; Brown, Alison; Drazen, Jeffrey M; Kwiatkowski, David J; Chapman, Harold A; Campbell, Edward J; Province, Michael A; Rao, D C; Reilly, John J; Ginns, Leo C; Speizer, Frank E; Weiss, Scott T

    2002-03-15

    Familial aggregation of chronic obstructive pulmonary disease (COPD) has been demonstrated, but linkage analysis of COPD-related phenotypes has not been reported previously. An autosomal 10 cM genome-wide scan of short tandem repeat (STR) polymorphic markers was analyzed for linkage to COPD-related phenotypes in 585 members of 72 pedigrees ascertained through severe, early-onset COPD probands without severe alpha1-antitrypsin deficiency. Multipoint non-parametric linkage analysis (using the ALLEGRO program) was performed for qualitative phenotypes including moderate airflow obstruction [forced expiratory volume at one second (FEV(1)) < 60% predicted, FEV(1)/FVC < 90% predicted], mild airflow obstruction (FEV(1) < 80% predicted, FEV(1)/FVC < 90% predicted) and chronic bronchitis. The strongest evidence for linkage in all subjects was observed at chromosomes 12 (LOD = 1.70) and 19 (LOD = 1.54) for moderate airflow obstruction, chromosomes 8 (LOD = 1.36) and 19 (LOD = 1.09) for mild airflow obstruction and chromosomes 19 (LOD = 1.21) and 22 (LOD = 1.37) for chronic bronchitis. Restricting analysis to cigarette smokers only provided increased evidence for linkage of mild airflow obstruction and chronic bronchitis to several genomic regions; for mild airflow obstruction in smokers only, the maximum LOD was 1.64 at chromosome 19, whereas for chronic bronchitis in smokers only, the maximum LOD was 2.08 at chromosome 22. On chromosome 12p, 12 additional STR markers were genotyped, which provided additional support for an airflow obstruction locus in that region with a non-parametric multipoint approach for moderate airflow obstruction (LOD = 2.13) and mild airflow obstruction (LOD = 1.43). Using a dominant model with the STR markers on 12p, two point parametric linkage analysis of all subjects demonstrated a maximum LOD score of 2.09 for moderate airflow obstruction and 2.61 for mild airflow obstruction. In smokers only, the maximum two point LOD score for mild airflow

  19. Design of a High Performance Reversible Multiplier

    Directory of Open Access Journals (Sweden)

    Md.Belayet Ali

    2011-11-01

    Full Text Available Reversible logic circuits are increasingly used in power minimization having applications such as low power CMOS design, optical information processing, DNA computing, bioinformatics, quantum computing and nanotechnology. The problem of minimizing the number of garbage outputs is an important issue in reversible logic design. In this paper we propose a new 44 universal reversible logic gate. The proposed reversible gate can be used to synthesize any given Boolean functions. The proposed reversible gate also can be used as a full adder circuit. In this paper we have used Peres gate and the proposed Modified HNG (MHNG gate to construct the reversible fault tolerant multiplier circuit. We show that the proposed 44 reversible multiplier circuit has lower hardware complexity and it is much better and optimized in terms of number of reversible gates and number of garbage outputs with compared to the existing counterparts.

  20. Analysis of reverse heat transfer for conventional and optimized lubri-cooling methods during tangential surface grinding of ABNT 1020 steel

    Directory of Open Access Journals (Sweden)

    Henrique Cotait Razuk

    Full Text Available Abstract A numerical thermal model was developed to evaluate the heat flux which is conducted to a rectangular workpiece of steel plate ABNT 1020, thus making it possible to compute the maximum temperature in the grinding surface, taking into account the rectangular distribution of heat flux, the thermal properties of the grinding wheel conventional Al2O3, the piece to be machined and the lubri-refrigerating fluid. The finite volume method was employed for the discretization of the direct thermal problem from the heat diffusion equation associated with the two-dimensional problem of heat conduction in transient regime. The inverse thermal problem was solved by the Golden Section technique. The thermal flux, when compared to the conventional technique of method of application fluid, was reduced by 84.0% in the practices performed with cutting depth of 30µm, at 74.0% in practices with cutting depth of 45µm and 61.2% in the aggressive practices of 60µm, thus demonstrating the applicability of the optimized method for fluid application.

  1. Two models of high frequency chest compression therapy: interaction of jacket pressure and mouth airflow.

    Science.gov (United States)

    Lee, Yong Wan; Lee, Jongwon; Warwick, Warren J

    2007-01-01

    High frequency chest compression (HFCC) therapy assists clearing the secretions in the lung. This paper presents two mathematical models: 1) HFCC jacket function model (JFM) and 2) respiratory function model (RFM). JFM predicts the variation of the jacket pressure (Pj) from the respiratory pattern of mouth airflow (Fm). RFM predicts the HFCC induced mouth airflow (Fm) from the HFCC pulse pressures at the jacket (Pj). Fm and Pj were measured from a healthy subject during HFCC therapy. JFM, which was implemented with 2nd order system using prediction error method, shows the existence of breathing pattern at Pj. RFM, which was implemented with amplitude modulation technique, shows how the HFCC pulses affects to the Fm. JFM calculations match 78% of the measured respiratory pattern of Pj>. RFM calculations match 90% of measured HFCC induced Fm. These models can be used to test new breathing patterns before designing studies on patients having chronic obstructive pulmonary diseases.

  2. Airflow energy harvesters of metal-based PZT thin films by self-excited vibration

    Science.gov (United States)

    Suwa, E.; Tsujiura, Y.; Kurokawa, F.; Hida, H.; Kanno, I.

    2014-11-01

    We developed self-excited vibration energy harvesters of Pb(Zr,Ti)O3 (PZT) thin films using airflow. To enhance the self-excited vibration, we used 30-μm-thick stainless steel (SS304) foils as base cantilevers on which PZT thin films were deposited by rf-magnetron sputtering. To compensate for the initial bending of PZT/SS304 unimorph cantilever due to the thermal stress, we deposited counter PZT thin films on the back of the SS304 cantilever. We evaluated power-generation performance and vibration mode of the energy harvester in the airflow. When the angle of attack (AOA) was 20° to 30°, large vibration was generated at wind speeds over 8 m/s. By FFT analysis, we confirmed that stable self-excited vibration was generated. At the AOA of 30°, the output power reached 19 μW at wind speeds of 12 m/s.

  3. Majority of never-smokers with airflow limitation do not have asthma

    DEFF Research Database (Denmark)

    Çolak, Yunus; Afzal, Shoaib; Nordestgaard, Børge G

    2016-01-01

    , ischaemic heart disease, myocardial infarction, deep venous thrombosis and PE) during 4.5 years median follow-up. RESULTS: NS+AFL-A compared with NS+AFL+A reported less allergy and respiratory symptoms, and had higher FEV1 and lower levels of eosinophils and IgE in peripheral blood. NS+AFL+A had increased......-AFL-A. CONCLUSIONS: Majority of NS+AFL-A do not seem to have undiagnosed asthma and may instead have airflow limitation caused by other risk factors....... 102 (42%) were never-smokers. In this group, 13 719 (35%) reported to have respiratory symptoms of whom 1610 (12%) had airflow limitation. We investigated characteristics and risk of complications (asthma or COPD exacerbations, pneumonias and all-cause mortality) and comorbidities (lung cancer...

  4. Study of airflow during respiratory cycle in semi-realistic model of human tracheobronchial tree

    Science.gov (United States)

    Elcner, Jakub; Zaremba, M.; Maly, M.; Jedelsky, J.; Lizal, F.; Jicha, M.

    2016-06-01

    This article deals with study of airflow under breathing process, which is characteristic by unsteady behavior. Simulations provided by computational fluid dynamics (CFD) was compared with experiments performed on similar geometry of human upper airways. This geometry was represented by mouth cavity of realistic shape connected to an idealized tracheobronchial tree up to fourth generation of branching. Commercial CFD software Star-CCM+ was used to calculate airflow inside investigated geometry and method of Reynolds averaging of Navier-Stokes equations was used for subscribing the turbulent behavior through model geometry. Conditions corresponding to resting state were considered. Comparisons with experiments were provided on several points through trachea and bronchial tree and results with respect to inspiratory and respiratory part of breathing cycle was discussed.

  5. Airflow and Contaminant Distribution in Hospital Wards with a Displacement Ventililation System

    DEFF Research Database (Denmark)

    Qian, H.; Nielsen, Peter Vilhelm; Li, Y.

    2004-01-01

    Airflow and Contaminant Distribution in Hospital Wards with a Displacement Ventilalation System. The 2nd International Conference on Build Environment and Public Health, BEPH 2004, Shenzhen , China . ABSTRACT Displacement ventilation has not been considered to be an applicable system for hospital...... to accurately predict three-dimensional distribution of air velocity, temperature, and contaminant concentration in the ward. Indoor airflow in a displacement ventilation system involves a combination of different flow streams such as the gravity currents and thermal plumes. It is important to choose...... assisted us to understand the contaminant dispersion. It was shown that the interaction of exhaled flow and the body thermal plume generated by manikin would affect exhaled virus-laden aerosols distribution in the ward with displacement ventilation system....

  6. Mechanical Design of a Performance Test Rig for the Turbine Air-Flow Task (TAFT)

    Science.gov (United States)

    Forbes, John C.; Xenofos, George D.; Farrow, John L.; Tyler, Tom; Williams, Robert; Sargent, Scott; Moharos, Jozsef

    2004-01-01

    To support development of the Boeing-Rocketdyne RS84 rocket engine, a full-flow, reaction turbine geometry was integrated into the NASA-MSFC turbine air-flow test facility. A mechanical design was generated which minimized the amount of new hardware while incorporating all test and instrumentation requirements. This paper provides details of the mechanical design for this Turbine Air-Flow Task (TAFT) test rig. The mechanical design process utilized for this task included the following basic stages: Conceptual Design. Preliminary Design. Detailed Design. Baseline of Design (including Configuration Control and Drawing Revision). Fabrication. Assembly. During the design process, many lessons were learned that should benefit future test rig design projects. Of primary importance are well-defined requirements early in the design process, a thorough detailed design package, and effective communication with both the customer and the fabrication contractors.

  7. Characterizing Indoor Airflow and Pollutant Transport using Simulation Modeling for Prototypical Buildings. I. Office Buildings

    Energy Technology Data Exchange (ETDEWEB)

    Sohn, M.D.; Daisey, J.M.; Feustel, H.E.

    1999-06-01

    This paper describes the first efforts at developing a set of prototypical buildings defined to capture the key features affecting airflow and pollutant transport in buildings. These buildings will be used to model airflow and pollutant transport for emergency response scenarios when limited site-specific information is available and immediate decisions must be made, and to better understand key features of buildings controlling occupant exposures to indoor pollutant sources. This paper presents an example of this approach for a prototypical intermediate-sized, open style, commercial building. Interzonal transport due to a short-term source release, e.g., accidental chemical spill, in the bottom and the upper floors is predicted and corresponding HVAC system operation effects and potential responses are considered. Three-hour average exposure estimates are used to compare effects of source location and HVAC operation.

  8. Computational fluid dynamics modeling of airflow inside lungs using heterogenous anisotropic lung tissue elastic properties.

    Science.gov (United States)

    Ilegbusi, Olusegun; Li, Ziang; Min, Yugang; Meeks, Sanford; Kupelian, Patrick; Santhanam, Anand P

    2012-01-01

    The aim of this paper is to model the airflow inside lungs during breathing and its fluid-structure interaction with the lung tissues and the lung tumor using subject-specific elastic properties. The fluid-structure interaction technique simultaneously simulates flow within the airway and anisotropic deformation of the lung lobes. The three-dimensional (3D) lung geometry is reconstructed from the end-expiration 3D CT scan datasets of humans with lung cancer. The lung is modeled as a poro-elastic medium with anisotropic elastic property (non-linear Young's modulus) obtained from inverse lung elastography of 4D CT scans for the same patients. The predicted results include the 3D anisotropic lung deformation along with the airflow pattern inside the lungs. The effect is also presented of anisotropic elasticity on both the spatio-temporal volumetric lung displacement and the regional lung hysteresis.

  9. Payload bay atmospheric vent airflow testing at the Vibration and Acoustic Test Facility

    Science.gov (United States)

    Johnston, James D., Jr.

    1988-01-01

    Several concerns related to venting the Space Shuttle Orbiter payload bay during launch led to laboratory experiments with a flight-type vent box installed in the wall of a subsonic wind tunnel. This report describes the test setups and procedures used to acquire data for characterization of airflow through the vent box and acoustic tones radiated from the vent-box cavity. A flexible boundary-layer spoiler which reduced the vent-tone amplitude is described.

  10. CT-diagnosed emphysema and prognosis of chronic airflow obstruction: a retrospective study

    OpenAIRE

    Kurashima, Kazuyoshi; Fukuda, Chiaki; Nakamoto, Keitaro; Takaku, Yotaro; Hijikata, Naoya; Hoshi, Toshiko; Kanauchi, Tetsu; Ueda, Miyuki; Takayanagi, Noboru; Sugita, Yutaka; Araki, Ryuichiro

    2013-01-01

    Objective CT-diagnosed emphysema is associated with poor prognosis in chronic obstructive pulmonary disease (COPD). Its clinical impacts on prognoses of asthma with chronic airflow obstruction (CAO) are not well known. We sought to compare mortalities and prognostic factors in COPD and asthma with CAO by the presence or absence of CT-diagnosed emphysema. Design Retrospective cohort study. Setting Referral centre hospital for respiratory disease. Participants 1272 patients aged over 40 years w...

  11. THE ANALYSIS FOR THE AIRFLOW EXCITING-VIBRATION FORCE OF CONTROL STAGE OF STEAM TURBINE

    Institute of Scientific and Technical Information of China (English)

    柴山; 张耀明; 马浩; 曲庆文; 赵又群

    2001-01-01

    Based on the hydrodynamics, the airflow exciting-vibration force of control stage of steam turbine is studied by using the momentum theorem. A formulation for calculating the air exciting-vibration force of the control stage of steam turbine is deduced first by using theoretical analysis method and taking all the design factors of vane and nozzles into consideration. Moreover, the exciting-vibration forces in different load cases are discussed respectively.

  12. Airflow study of pathologic larynges using a constant temperature anemometer: further experience.

    Science.gov (United States)

    Kitajima, K; Fujita, F

    1992-08-01

    Phonatory airflow was recorded in 361 laryngeal disease patients and 59 normal subjects by using a constant temperature anemometer to measure Isshiki's proposed parameter, the AC/DC percentage. The pathologic groups displayed AC/DC percentage values smaller than those of the normal group. The value differentials observed among the various diseases suggest that the AC/DC percentage may reflect the vibrational capacity of the vocal cords.

  13. Description of the airflow produced by an air-assisted sprayer during pesticide applications to citrus

    OpenAIRE

    Ramon Salcedo; Cruz Garcera; Rafael Granell; Enrique Molto; Patricia Chueca

    2015-01-01

    Atmospheric drift of plant protection products is considered a major source of air pollution during pesticide applications. Citrus protection against pests and diseases usually requires application of these products using air-blast sprayers. Many authors have emphasized the influence of vegetation on the risk of spray drift. The aim of this work was to describe in detail how the airflow from an air-blast sprayer behaves when it reaches citrus trees and, in particular, the effect that the tree...

  14. Airflow characteristics and pollution distribution around a thermal manikin - Impact of specific personal and indoor environmental factors

    DEFF Research Database (Denmark)

    Licina, Dusan; Tham, Kwok Wai; Melikov, Arsen Krikor

    2016-01-01

    This study presents a summary of experimental measurements on the airflow characteristics and pollution distribution around a non-breathing thermal manikin. The two objectives are: (1) to examine the extent to which personal (body posture, clothing insulation, table positioning) and environmental...... pollutants under factors that influence the CBL. The results show that the CBL generated by the thermal manikin influenced the airflow characteristics and pollution distribution in the breathing zone. Parameters such as room air temperature, body posture, clothing insulation, table positioning...

  15. Group differences in measures of voice production and revised values of maximum airflow declination rate.

    Science.gov (United States)

    Perkell, J S; Hillman, R E; Holmberg, E B

    1994-08-01

    In previous reports, aerodynamic and acoustic measures of voice production were presented for groups of normal male and female speakers [Holmberg et al., J. Acoust. Soc. Am. 84, 511-529 (1988); J. Voice 3, 294-305 (1989)] that were used as norms in studies of voice disorders [Hillman et al., J. Speech Hear. Res. 32, 373-392 (1989); J. Voice 4, 52-63 (1990)]. Several of the measures were extracted from glottal airflow waveforms that were derived by inverse filtering a high-time-resolution oral airflow signal. Recently, the methods have been updated and a new study of additional subjects has been conducted. This report presents previous (1988) and current (1993) group mean values of sound pressure level, fundamental frequency, maximum airflow declination rate, ac flow, peak flow, minimum flow, ac-dc ratio, inferred subglottal air pressure, average flow, and glottal resistance. Statistical tests indicate overall group differences and differences for values of several individual parameters between the 1988 and 1993 studies. Some inter-study differences in parameter values may be due to sampling effects and minor methodological differences; however, a comparative test of 1988 and 1993 inverse filtering algorithms shows that some lower 1988 values of maximum flow declination rate were due at least in part to excessive low-pass filtering in the 1988 algorithm. The observed differences should have had a negligible influence on the conclusions of our studies of voice disorders.

  16. Development of an Indoor Airflow Energy Harvesting System for Building Environment Monitoring

    Directory of Open Access Journals (Sweden)

    Fei Fei

    2014-05-01

    Full Text Available Wireless sensor networks (WSNs have been widely used for intelligent building management applications. Typically, indoor environment parameters such as illumination, temperature, humidity and air quality are monitored and adjusted by an intelligent building management system. However, owing to the short life-span of the batteries used at the sensor nodes, the maintenance of such systems has been labor-intensive and time-consuming. This paper discusses a battery-less self-powering system that converts the mechanical energy from the airflow in ventilation ducts into electrical energy. The system uses a flutter energy conversion device (FECD capable of working at low airflow speeds while installed on the ventilation ducts inside of buildings. A power management strategy implemented with a circuit system ensures sufficient power for driving commercial electronic devices. For instance, the power management circuit is capable of charging a 1 F super capacitor to 2 V under ventilation duct airflow speeds of less than 3 m/s.

  17. Elasto-Aerodynamics-Driven Triboelectric Nanogenerator for Scavenging Air-Flow Energy.

    Science.gov (United States)

    Wang, Shuhua; Mu, Xiaojing; Wang, Xue; Gu, Alex Yuandong; Wang, Zhong Lin; Yang, Ya

    2015-10-27

    Efficient scavenging the kinetic energy from air-flow represents a promising approach for obtaining clean, sustainable electricity. Here, we report an elasto-aerodynamics-driven triboelectric nanogenerator (TENG) based on contact electrification. The reported TENG consists of a Kapton film with two Cu electrodes at each side, fixed on two ends in an acrylic fluid channel. The relationship between the TENG output power density and its fluid channel dimensions is systematically studied. TENG with a fluid channel size of 125 × 10 × 1.6 mm(3) delivers the maximum output power density of about 9 kW/m(3) under a loading resistance of 2.3 MΩ. Aero-elastic flutter effect explains the air-flow induced vibration of Kapton film well. The output power scales nearly linearly with parallel wiring of multiple TENGs. Connecting 10 TENGs in parallel gives an output power of 25 mW, which allows direct powering of a globe light. The TENG is also utilized to scavenge human breath induced air-flow energy to sustainably power a human body temperature sensor.

  18. Hybridized electromagnetic-triboelectric nanogenerator for scavenging air-flow energy to sustainably power temperature sensors.

    Science.gov (United States)

    Wang, Xue; Wang, Shuhua; Yang, Ya; Wang, Zhong Lin

    2015-04-28

    We report a hybridized nanogenerator with dimensions of 6.7 cm × 4.5 cm × 2 cm and a weight of 42.3 g that consists of two triboelectric nanogenerators (TENGs) and two electromagnetic generators (EMGs) for scavenging air-flow energy. Under an air-flow speed of about 18 m/s, the hybridized nanogenerator can deliver largest output powers of 3.5 mW for one TENG (in correspondence of power per unit mass/volume: 8.8 mW/g and 14.6 kW/m(3)) at a loading resistance of 3 MΩ and 1.8 mW for one EMG (in correspondence of power per unit mass/volume: 0.3 mW/g and 0.4 kW/m(3)) at a loading resistance of 2 kΩ, respectively. The hybridized nanogenerator can be utilized to charge a capacitor of 3300 μF to sustainably power four temperature sensors for realizing self-powered temperature sensor networks. Moreover, a wireless temperature sensor driven by a hybridized nanogenerator charged Li-ion battery can work well to send the temperature data to a receiver/computer at a distance of 1.5 m. This work takes a significant step toward air-flow energy harvesting and its potential applications in self-powered wireless sensor networks.

  19. Human-mediated dispersal of seeds by the airflow of vehicles.

    Science.gov (United States)

    von der Lippe, Moritz; Bullock, James M; Kowarik, Ingo; Knopp, Tatjana; Wichmann, Matthias C; Wichmann, Matthias

    2013-01-01

    Human-mediated dispersal is known as an important driver of long-distance dispersal for plants but underlying mechanisms have rarely been assessed. Road corridors function as routes of secondary dispersal for many plant species but the extent to which vehicles support this process remains unclear. In this paper we quantify dispersal distances and seed deposition of plant species moved over the ground by the slipstream of passing cars. We exposed marked seeds of four species on a section of road and drove a car along the road at a speed of 48 km/h. By tracking seeds we quantified movement parallel as well as lateral to the road, resulting dispersal kernels, and the effect of repeated vehicle passes. Median distances travelled by seeds along the road were about eight meters for species with wind dispersal morphologies and one meter for species without such adaptations. Airflow created by the car lifted seeds and resulted in longitudinal dispersal. Single seeds reached our maximum measuring distance of 45 m and for some species exceeded distances under primary dispersal. Mathematical models were fit to dispersal kernels. The incremental effect of passing vehicles on longitudinal dispersal decreased with increasing number of passes as seeds accumulated at road verges. We conclude that dispersal by vehicle airflow facilitates seed movement along roads and accumulation of seeds in roadside habitats. Dispersal by vehicle airflow can aid the spread of plant species and thus has wide implications for roadside ecology, invasion biology and nature conservation.

  20. A model of airflow in the nasal cavities: Implications for nasal air conditioning and epistaxis.

    Science.gov (United States)

    Bailie, Neil; Hanna, Brendan; Watterson, John; Gallagher, Geraldine

    2009-01-01

    A friction force is generated when moving air contacts the nasal walls, referred to as wall shear stress. This interaction facilitates heat and mass transfer between the mucosa and air, i.e., air-conditioning. The objective of this research was to study the distribution of wall shear stress within the nasal cavity to identify areas that contribute significantly to air-conditioning within the nasal cavity. Three-dimensional computational models of the nasal airways of five healthy subjects (three male and two female subjects) were constructed from nasal CT scans. Numerical simulations of nasal airflow were conducted using the commercial computational fluid dynamics code Fluent 6 (Ansys, Inc., Canonsburg, PA). Wall shear stress was derived from the numerical simulation. Air-conditioning was simulated to confirm the relationship with wall shear stress. Nasal airflow simulations predicted high wall shear stress along the anterior aspect of the inferior turbinate, the anteroinferior aspect of the middle turbinate, and within Little's area. The airflow simulations indicate that the inferior and middle turbinates and Little's area on the anterior nasal septum contribute significantly to nasal air-conditioning. The concentration of wall shear stress within Little's area indicates a desiccating and potentially traumatic effect of inhaled air that may explain the predilection for spontaneous epistaxis at this site.

  1. Human-mediated dispersal of seeds by the airflow of vehicles.

    Directory of Open Access Journals (Sweden)

    Moritz von der Lippe

    Full Text Available Human-mediated dispersal is known as an important driver of long-distance dispersal for plants but underlying mechanisms have rarely been assessed. Road corridors function as routes of secondary dispersal for many plant species but the extent to which vehicles support this process remains unclear. In this paper we quantify dispersal distances and seed deposition of plant species moved over the ground by the slipstream of passing cars. We exposed marked seeds of four species on a section of road and drove a car along the road at a speed of 48 km/h. By tracking seeds we quantified movement parallel as well as lateral to the road, resulting dispersal kernels, and the effect of repeated vehicle passes. Median distances travelled by seeds along the road were about eight meters for species with wind dispersal morphologies and one meter for species without such adaptations. Airflow created by the car lifted seeds and resulted in longitudinal dispersal. Single seeds reached our maximum measuring distance of 45 m and for some species exceeded distances under primary dispersal. Mathematical models were fit to dispersal kernels. The incremental effect of passing vehicles on longitudinal dispersal decreased with increasing number of passes as seeds accumulated at road verges. We conclude that dispersal by vehicle airflow facilitates seed movement along roads and accumulation of seeds in roadside habitats. Dispersal by vehicle airflow can aid the spread of plant species and thus has wide implications for roadside ecology, invasion biology and nature conservation.

  2. Comparative analysis of realistic CT-scan and simplified human airway models in airflow simulation.

    Science.gov (United States)

    Johari, Nasrul Hadi; Osman, Kahar; Helmi, Nor Harris N; Abdul Kadir, Mohammed A Rafiq

    2015-01-01

    Efforts to model the human upper respiratory system have undergone many phases. Geometrical proximity to the realistic shape has been the subject of many research projects. In this study, three different geometries of the trachea and main bronchus were modelled, which were reconstructed from computed tomography (CT) scan images. The geometrical variations were named realistic, simplified and oversimplified. Realistic refers to the lifelike image taken from digital imaging and communications in medicine format CT scan images, simplified refers to the reconstructed image based on natural images without realistic details pertaining to the rough surfaces, and oversimplified describes the straight wall geometry of the airway. The characteristics of steady state flows with different flow rates were investigated, simulating three varied physical activities and passing through each model. The results agree with previous studies where simplified models are sufficient for providing comparable results for airflow in human airways. This work further suggests that, under most exercise conditions, the idealised oversimplified model is not favourable for simulating either airflow regimes or airflow with particle depositions. However, in terms of immediate analysis for the prediction of abnormalities of various dimensions of human airways, the oversimplified techniques may be used.

  3. Large-eddy simulation of airflow and heat transfer in a general ward of hospital

    Science.gov (United States)

    Hasan, Md. Farhad; Himika, Taasnim Ahmed; Molla, Md. Mamun

    2016-07-01

    In this paper, a very popular alternative computational technique, the Lattice Boltzmann Method (LBM) has been used for Large-Eddy Simulation (LES) of airflow and heat transfer in general ward of hospital. Different Reynolds numbers have been used to study the airflow pattern. In LES, Smagorinsky turbulence model has been considered and a discussion has been conducted in brief. A code validation has been performed comparing the present results with benchmark results for lid-driven cavity problem and the results are found to agree very well. LBM is demonstrated through simulation in forced convection inside hospital ward with six beds with a partition in the middle, which acted like a wall. Changes in average rate of heat transfer in terms of average Nusselt numbers have also been recorded in tabular format and necessary comparison has been showed. It was found that partition narrowed the path for airflow and once the air overcame this barrier, it got free space and turbulence appeared. For higher turbulence, the average rate of heat transfer increased and patients near the turbulence zone released maximum heat and felt more comfortable.

  4. Sleep position and the ocular surface in a high airflow environment

    Science.gov (United States)

    Gauba, Vinod; Curtis, Zoe J.

    2013-01-01

    Purpose To study the relationship between sleep position and ocular surface symptoms and signs in an high air flow environment. Methods Prospective observational study of new patients attending the dry eye clinic was performed. Patients with pre-existing ocular history, relevant systemic history (e.g. Sjogren’s syndrome) or who were using topical or systemic therapy for dry eye were not included. Data were collected from the patient to document their dry eye symptoms; preferred dependent sleeping side and their bedroom airflow. All patients were examined by a clinician blind to the patient’s responses where Schirmer’s test and slit lamp examination were performed looking for the presence of lagophthalmos and corneal epitheliopathy. Results 48 patients enrolled into the study of which 23 were males and 25 were females with a normal and comparable age distribution. The study found a strong association between patients’ preferred sleeping side and the incidence of corneal epitheliopathy in the contralateral eye particularly in patients with evidence of lagophthalmos. Dry eye symptoms were found to be worse and tear production lower on the contralateral side to the preferred sleeping side particularly in patients who sleep in a high airflow environment. Conclusion In patients sleeping in a high airflow environment with nocturnal lagophthalmos, this study observed an association between preferred dependent sleep position and increased dry eye symptoms, lower Schirmer’s scores and increased corneal epitheliopathy in the contralateral eye. PMID:24526862

  5. Characteristics of airflow in a CT-based ovine lung: a numerical study.

    Science.gov (United States)

    Kabilan, Senthil; Lin, Ching-Long; Hoffman, Eric A

    2007-04-01

    The transient airflow in a rigid, asymmetric monopodial sheep (ovine) tracheobronchial tree of up to 13 generations was investigated numerically. The lung geometry was segmented and reconstructed from computed-tomographic (CT) images. The flow characteristics in the image-based sheep airway were compared with the flow patterns produced by a Weibel-based model at prime locations. Boundary conditions were prescribed 1) a velocity profile from experimental data at the inlet and 2) zero pressure at the bronchial outlets. A mesh convergence study was carried out to establish confidence in the model predictions, and gross left-right ventilation was validated against experimental xenon wash-in-washout data. Detailed flow characteristics were investigated at three points in the breathing cycle: 1) peak inhalation, 2) peak exhalation, and 3) transition. Simulation results revealed fundamental differences between airflow in monopodial and bipodial branching airways. Compared with idealized bipodial flow, the flow in the sheep airway was asymmetric and highly vortical, especially during exhalation and transition. The streak lines during the inhalation phase suggest that the left and right upper lobes are ventilated by airflow in the peripheral region of the trachea. This work may contribute to understanding the interplay between structure and function in the lung.

  6. Modeling and Assessment of Buoyancy-Driven Stratified Airflow in High-Space Industrial Hall

    Institute of Scientific and Technical Information of China (English)

    WANG Han-qing; CHEN Ke; HU Jian-jun; KOU Guang-xiao; WANG Zhi-yong

    2009-01-01

    In industrial environment,heat sources often are contaminant sources and health threatening con-taminants are mainly passive,so a detailed understanding of airflow mode can assist in work environment hy-giene measurement and prevention.This paper presented a numerical investigation of stratified airflow scenario in a high-space industrial hall with validated commercial code and experimentally acquired boundary conditions.Based upon an actually undergoing engineering project,this study investigated the performance of the buoyancy-driven displacement ventilation in a large welding hall with big components manufactured.The results have demonstrated that stratified airflow sustained by thermal buoyancy provides zoning effect in terms of clean and polluted regions except minor stagnant eddy areas.The competition between negative buoyant jets from displace-ment radial diffusers and positive buoyant plume from bulk object constitutes the complex transport characteris-tics under and above stratification interface.Entrainment,downdraft and turbulent eddy motion complicate the upper mixing zone,but the exhaust outlet plays a less important role in the whole field flow.And the corre-sponding suggestions concerning computational stability and convergence,further improvements in modeling and measurements were given.

  7. Emphysema predicts hospitalisation and incident airflow obstruction among older smokers: a prospective cohort study.

    Directory of Open Access Journals (Sweden)

    David A McAllister

    Full Text Available BACKGROUND: Emphysema on CT is common in older smokers. We hypothesised that emphysema on CT predicts acute episodes of care for chronic lower respiratory disease among older smokers. MATERIALS AND METHODS: Participants in a lung cancer screening study age ≥ 60 years were recruited into a prospective cohort study in 2001-02. Two radiologists independently visually assessed the severity of emphysema as absent, mild, moderate or severe. Percent emphysema was defined as the proportion of voxels ≤ -910 Hounsfield Units. Participants completed a median of 5 visits over a median of 6 years of follow-up. The primary outcome was hospitalization, emergency room or urgent office visit for chronic lower respiratory disease. Spirometry was performed following ATS/ERS guidelines. Airflow obstruction was defined as FEV1/FVC ratio <0.70 and FEV1<80% predicted. RESULTS: Of 521 participants, 4% had moderate or severe emphysema, which was associated with acute episodes of care (rate ratio 1.89; 95% CI: 1.01-3.52 adjusting for age, sex and race/ethnicity, as was percent emphysema, with similar associations for hospitalisation. Emphysema on visual assessment also predicted incident airflow obstruction (HR 5.14; 95% CI 2.19-21.1. CONCLUSION: Visually assessed emphysema and percent emphysema on CT predicted acute episodes of care for chronic lower respiratory disease, with the former predicting incident airflow obstruction among older smokers.

  8. Airflow and autonomic responses to stress and relaxation in asthma: the impact of stressor type.

    Science.gov (United States)

    Aboussafy, David; Campbell, Tavis S; Lavoie, Kim; Aboud, Frances E; Ditto, Blaine

    2005-09-01

    The impact of stress on respiratory airflow in asthmatics is unclear. Part of the uncertainty may spring from the different physiological effects of different stressors. Given their potential to elicit increases in parasympathetic vagal activity, stressful situations that present few opportunities for coping (passive coping stressors) may be particularly problematic for people with asthma. Thirty-one adult asthmatics participated in a protocol including a widely used passive coping stressor (the cold pressor test), an active coping stressor (mental arithmetic), an interview about an upsetting asthma-related incident (viewed as a potential passive coping stressor given the exposure to unpleasant memories), and progressive muscle relaxation. Repeated measurements of airflow (via peak expiratory flow), vagal tone (via heart rate variability), and other variables were obtained. The cold pressor test, asthma interview and progressive muscle relaxation produced significant decreases in airflow compared to the baseline period. The cold pressor test and progressive muscle relaxation produced significant, complementary increases in vagal tone. These results suggest that passive coping stressors and other stimuli (e.g., certain forms of relaxation) that elicit increased vagal tone may be associated with poorer asthma control, a view consistent with a significant negative correlation between the participant's mean vagal tone response to the tasks and score on a measure of asthma self-efficacy.

  9. Airflow and thermal simulation in a controlled test chamber with different heating configurations using CFD modeling

    Energy Technology Data Exchange (ETDEWEB)

    Candanedo, L.; Karava, P.; Bessoudo, M.; Tzempelikos, A.; Athienitis, A. [Concordia Univ., Montreal, PQ (Canada). Dept. of Building, Civil and Environmental Engineering; Handfield, L. [Inst. de Recherche d' Hydro-Quebec, Shawnigan, PQ (Canada)

    2007-07-01

    Efficient windows and facades can reduce perimeter heating and energy consumption costs in buildings. In this study, 3-D computational fluid dynamics (CFD) models were developed to model airflow and heat transfer in a controlled test chamber at a Hydro-Quebec laboratory. The aim of the study was to investigate thermofluidic phenomena in the vicinity of windows and facades for rooms heated with baseboard heaters and rooms heated with heated windows. The particle image velocimetry (PIV) technique was employed to study the airflow in a plane close to a window that was heated with either embedded heaters or indirectly with a baseboard heater. The PIV system was synchronized with a data acquisition system which collected temperature data from the 4 walls, ceiling, floor, and each of the 5 windows. Time-averaged values were used for boundaries. Navier-Stokes equations were used to calculate laminar flow and heat transfer. An indoor zero-equation turbulence model was used to characterize indoor airflow. The Rayleigh number was used to categorize the nature of the buoyancy-induced flow. The simulations showed good agreement with experimental data. The largest differences in air speed measurements were found in the cavity formed by the blind and the window glazing. 6 refs., 3 tabs., 11 figs.

  10. Optimal design of reversible pump-turbine runner%可逆式水泵水轮机转轮的三维反问题优化设计

    Institute of Scientific and Technical Information of China (English)

    王旭鹤; 祝宝山; 曹树良; 谭磊

    2014-01-01

    at both the pump and turbine modes by a trial and error method. In the present paper, a 3D inverse design method, CFD calculations, and multi-objective optimization strategy were coupled, and an optimal design system was built to improve the performances of a reversible pump-turbine runner. In the system, by using a 3D inverse design method, the runner shape was obtained by inputting corresponding parameters. A validated CFD method was used to estimate runner performances under different operating conditions. A multi-objective optimization strategy was then adopted to search runners with good performances at both operating modes in the design space based on a response surface model between input parameters and runner performances. The optimal design system was capable of solving some difficulties in pump-turbine runner design, such as a long design cycle and difficulties in obtaining good performances at both pump and turbine modes. The system was used to optimally design a middle-high head reversible pump-turbine runner, in which blade loading and blade lean were chosen as the input parameters, runner efficiency at the pump design point and the turbine rated point were set as optimization objectives, and the head at pump design point was set as a constraint. Since the optimization calculations were based on a response surface model, performances of nearly 10 000 runners under different operating modes were estimated in several minutes. Three runners from the Pareto frontier were chosen for detailed validation. CFD results showed that the optimal runner had a high hydraulic efficiency of over 95% at both the pump and turbine modes, which indicated a great improvement in runner efficiency in the turbine mode and the maintenance of high efficiency at the pump mode as compared with the initial design. The effects of the input parameters on runner interior characteristics under different operating modes were also analyzed in this paper. The results showed that fore

  11. Optimal design and control of buoyancy-driven ventilation

    DEFF Research Database (Denmark)

    Terpager Andersen, Karl

    2016-01-01

    Relationships between airflow rates and opening areas of importance for design and control are analysed for buoyancy-driven ventilation in a room with two openings and uniform temperature. The optimal ratio between the inlet and outlet areas is found. The consequences of deviations from the optimum...

  12. Glottal airflow and transglottal air pressure measurements for male and female speakers in soft, normal, and loud voice.

    Science.gov (United States)

    Holmberg, E B; Hillman, R E; Perkell, J S

    1988-08-01

    Measurements on the inverse filtered airflow waveform (the "glottal waveform") and of estimated average transglottal pressure and glottal airflow were made from noninvasive recordings of productions of syllable sequences in soft, normal, and loud voice for 25 male and 20 female speakers. Statistical analyses showed that with change from normal to loud voice, both males and females produced loud voice with increased pressure, accompanied by increased ac flow and increased maximum airflow declination rate. With change from normal voice, soft voice was produced with decreased pressure, ac flow and maximum airflow declination rate, and increased dc and average flow. Within the loudness conditions, there was no significant male-female difference in air pressure. Several glottal waveform parameters separated males and females in normal and loud voice. The data indicate higher ac flow and higher maximum airflow declination rate for males. In soft voice, the male and female glottal waveforms were more alike, and there was no significant difference in maximum airflow declination rate. The dc flow did not differ significantly between males and females. Possible relevance to biomechanical differences and differences in voice source characteristics between males and females and across loudness conditions is discussed.

  13. Statistical data analysis method for multi-zonal airflow measurement using multiple kinds of perfluorocarbon tracer gas

    Energy Technology Data Exchange (ETDEWEB)

    Okuyama, Hiroyasu; Onishi, Yoshinori [Institute of Technology, Shimizu Corporation, 4-17, Etchujima 3-chome, Koto-ku, Tokyo 135-8530 (Japan); Tanabe, Shin-ichi [School of Science and Engineering, Department of Architecture, Waseda University, 3-4-1 Okubo, Shinjyuku-ku, Tokyo 169-8555 (Japan); Kashihara, Seiichi [R and D Laboratories, Asahi Kasei Homes Corporation, 2-1, Samejima Fuji-shi, Shizuoka 416-8501 (Japan)

    2009-03-15

    Conventional multi-zonal ventilation measurement methods by multiple types of perfluorocarbon tracers use a number of different gases equal to the number of zones (n). The possible n x n+n airflows are estimated from the mass balance of the gases and the airflow balance. However, some airflows may not occur because of inter-zonal geometry, and the introduction of unnecessary, unknown parameters can impair the accuracy of the estimation. Also, various error factors often yield an irrational negative airflow rate. Conventional methods are insufficient for the evaluation of error. This study describes a way of using the least-squares technique to improve the precision of estimation and to evaluate reliability. From the equations' residual, the error variance-covariance matrix {lambda}{sub q} of the estimated airflow rate error is deduced. In addition, the coefficient of determinant using the residual sum of squares and total variation is introduced. Furthermore, the error matrix{sub m}{lambda}{sub q} from the measurement errors in the gas concentration and gas emission rate is deduced. The discrepancy ratio of the model premises is defined by dividing the diagonal elements of the former by those of the latter. Moreover, the index of irrationality of the estimated negative airflow rate is defined, based on the different results of the three estimation methods. Some numerical experiments are also carried out to verify the flow rate estimation and the reliability evaluation theory. (author)

  14. Relationship between Pulmonary Airflow and Resistance in Patients with Airway Narrowing Using An 1-D Network Resistance and Compliance Model

    Science.gov (United States)

    Choi, Sanghun; Choi, Jiwoong; Hoffman, Eric; Lin, Ching-Long

    2016-11-01

    To predict the proper relationship between airway resistance and regional airflow, we proposed a novel 1-D network model for airway resistance and acinar compliance. First, we extracted 1-D skeletons at inspiration images, and generated 1-D trees of CT unresolved airways with a volume filling method. We used Horsfield order with random heterogeneity to create diameters of the generated 1-D trees. We employed a resistance model that accounts for kinetic energy and viscous dissipation (Model A). The resistance model is further coupled with a regional compliance model estimated from two static images (Model B). For validation, we applied both models to a healthy subject. The results showed that Model A failed to provide airflows consistent with air volume change, whereas Model B provided airflows consistent with air volume change. Since airflows shall be regionally consistent with air volume change in patients with normal airways, Model B was validated. Then, we applied Model B to severe asthmatic subjects. The results showed that regional airflows were significantly deviated from air volume change due to airway narrowing. This implies that airway resistance plays a major role in determining regional airflows of patients with airway narrowing. Support for this study was provided, in part, by NIH Grants U01 HL114494, R01 HL094315, R01 HL112986, and S10 RR022421.

  15. Optimization research on SDI test technology monitoring influent water quality in reverse osmosis system%反渗透系统进水SDI测试技术的优化研究

    Institute of Scientific and Technical Information of China (English)

    王旭亮; 潘献辉; 郝军; 张艳萍

    2013-01-01

    淤泥密度指数(SDI)作为重要的水质参数可以有效评价反渗透系统进水水质.开展反渗透系统进水SDI测试技术研究,考察各种测试条件和进水性质对SDI的影响,优化测试方法,从而实现对SDI准确高效的监测与分析.结果表明,SDI测试结果与测试条件密切相关,它随着测试时间间隔的缩短而增大,随着测试体积的增加而减小,随着测试水温的升高,SDI值会有增大的趋势,随着压力的增加,SDI值也会明显地增大;低浊度是反渗透系统进水的必要条件,测试时需控制进水的浊度在0.10 NTU以下.%Alstraet:Silt density index (SDI) is an important water quality parameter for evaluating influent water quality of reverse osmosis system.A research on SDI test technology monitoring influent water quality in reverse osmosis system was carried out.The effects of different conditions and influent water characteristics on SDI were investigated,and then,an optimized testing method was put forward,so as to realize the accurate and efficient monitoring of SDI.The test results showed that,SDI values were closely related to test conditions:it increased with the shortening of time interval between tests; decreased with the increasing of water sample volume; furthermore,along with the increasing of water temperature and pressure,SDI value also increased obviously.As low turbidity was a necessary characteristic of the influent water of reverse osmosis system,the turbidity of water sample should be controlled below 0.10 NTU during the SDI test.

  16. Human perception of air movement. Impact of frequency and airflow direction on draught sensation

    Energy Technology Data Exchange (ETDEWEB)

    Genhong Zhou

    1999-08-01

    Draught is defined as an unwanted local cooling of the human body caused by air movement. Air velocity and temperature are the main characteristics of air movement in rooms. Characteristics of instantaneous air velocity and temperature records previously measured in ventilated indoor spaces were analyzed. Air velocity and temperature fluctuated randomly. The amplitude and frequency of the fluctuations changed over time. Air movements around the human body were measured with a three-dimensional laser Doppler amemometer. A new parameter, equivalent frequency, was defined as an integral single parameter for describing the frequency characteristics of air velocity. The equivalent frequency of a randomly fluctuating velocity is defined as the frequency of sinusoidal velocity fluctuations with the same ratio of the standard deviation of acceleration to the standard deviation of air velocity as in the random velocity fluctuations. The equivalent frequencies of numerous instantaneous air-velocity records measured in ventilated space were analysed. The equivalent frequency of an airflow in an indoor space was found to be 0.1 to 2 Hz. The equivalent frequencies of most of the airflows were between 0.2 and 0.6 Hz. The relation between equivalent frequency and mean air velocity and standard deviation was established. Experiments were performed to identify the impact of the equivalent frequency on the human perception of draught. Forty subjects (20 women and 20 men) were subjected to airflows from behind with mean air velocities of 0.1, 0.2 and 0.3 m/s, with equivalent frequencies from 0 to 1 Hz at an air temperature of 20 deg. C. In this human-subject experimental study the frequency was found to have a significant impact on draught sensation. Subjects were more sensitive to airflow at an equivalent frequency between 0.2 and 0.6 Hz. A mathematical model for the simulation of draught was established and a computer program was developed for simulating the draught. The program

  17. [Reverse Chaddock sign].

    Science.gov (United States)

    Tashiro, Kunio

    2011-08-01

    It is widely accepted that the Babinski reflex is the most well-known and important pathological reflex in clinical neurology. Among many other pathological reflexes that elicit an upgoing great toe, such as Chaddock, Oppenheim, Gordon, Schaefer, and Stransky, only the Chaddock reflex is said to be as sensitive as the Babinski reflex. The optimal receptive fields of the Babinski and Chaddock reflexes are the lateral plantar surface and the external inframalleolar area of the dorsum, respectively. It has been said that the Babinski reflex, obtained by stroking the sole, is by far the best and most reliable method of eliciting an upgoing great toe. However, the Chaddock reflex, the external malleolar sign, is also considered sensitive and reliable according to the literature and everyday neurological practice. The major problems in eliciting the Babinski reflex by stroking the lateral part of the sole are false positive or negative responses due to foot withdrawal, tonic foot response, or some equivocal movements. On the other hand, according to my clinical experience, the external inframalleolar area, which is the receptive field of the Chaddock reflex, is definitely suitable for eliciting the upgoing great toe. In fact, the newly proposed method to stimulate the dorsum of the foot from the medial to the lateral side, which I term the "reversed Chaddock method," is equally sensitive to demonstrate pyramidal tract involvement. With the "reversed Chaddock method", the receptive field of the Chaddock reflex may be postulated to be in the territory of the sural nerve, which could be supported by the better response obtained on stimulation of the postero-lateral calf than the anterior shin. With regard to the receptive fields of the Babinski and Chaddock reflexes, the first sacral dermatome (S1) is also considered a reflexogenous zone, but since the dermatome shows marked overlapping, the zones vary among individuals. As upgoing toe responses are consistently observed in

  18. Decision-making for Reverse Logistics Network Optimization Considering Service Level%考虑服务水平的逆向物流网络优化决策

    Institute of Scientific and Technical Information of China (English)

    李爽; 王能民; 何正文; 马云高

    2013-01-01

    针对电子产品的售后维修服务问题,建立了一个同时考虑成本和服务质量的多目标逆向物流网络优化模型;该问题是多目标的NP-hard问题,应用NSGA-II算法和多目标模拟退火算法( MOSA )两种多目标进化算法,对模型进行求解并对其求解的效果进行比较分析;多组算例测试结果表明,NSGA-II相比MOSA更具优势。%This paper proposes a multi-objective reverse logistics network optimization model considering both cost and service level to help manufacturers of electronic products provide quality post-sale repair service for their consumers .Due to the NP-hard nature of the problem , two multi-objective evolutionary algorithms are employed including the Non-dominated Sorting Genetic Algorithm II ( NSGA-II ) and Multi-objective Simulated Annealing ( MOSA) .The performance of the two heuristic algorithms is compared using numerical examples .The computa-tional results show that NSGA-II outperforms MOSA .

  19. An optimized and validated RP-HPLC/UV detection method for simultaneous determination of all-trans-retinol (vitamin A) and alpha-tocopherol (vitamin E) in human serum: comparison of different particulate reversed-phase HPLC columns.

    Science.gov (United States)

    Khan, Abad; Khan, Muhammad I; Iqbal, Zafar; Shah, Yasar; Ahmad, Lateef; Watson, David G

    2010-09-01

    A novel, simple and fast reversed-phase HPLC/UV method was developed, optimized for various chromatographic conditions, and validated according to international guidelines for simultaneous determination of all-trans-retinol and alpha-tocopherol in human serum using retinyl acetate as internal standard in the concentration of 0.5 microg/ml. A liquid-phase extraction was applied to the 250 microl of serum with n-hexane-dichloromethane mixture (70:30, v/v), in two steps, using ethanol-methanol mixture (95:5, v/v) for protein precipitation and BHT (butylated hydroxy toluene) as stabilizer for sample preparation. Both analytes were analyzed on Kromasil 100 C(18) column (150 mm x 4.6 mm, 5 microm), Brownlee analytical (Perkin Elmer) C(18) column (150 mm x 4.6 mm, 5 microm), and Supelco (Supelcosil) LC-18 column (150 mm x 3 mm, 3 microm), protected by a Perkin Elmer C(18) (30 mm x 4.6 mm, 10 microm; Norwalk, USA) pre-column guard cartridge, at 292 nm wavelength, using methanol-water (99:1, v/v), in isocratic mode as mobile phase applied at flow rate of 1.5 ml/min and 1 ml/min for both 5 microm and 3 microm columns, respectively. Complete separation of all the analytes was achieved in 3 and 6 min on 3 microm and 5 microm columns, respectively by injecting 20 microl of sample into the HPLC system by autosampler, keeping column oven temperature at 25 degrees C. Different particulate reversed-phase chromatographic columns were evaluated in order to select the best column in terms of sensitivity, selectivity, resolution and short run time of both the analytes and it was concluded that 3 microm columns are better to be used in clinical set up as well as in laboratories for the separation of these analytes in a shorter time as compared with 5 microm columns. The method was validated and applied for the analysis of all-trans-retinol and alpha-tocopherol in the serum of human volunteers.

  20. Main bronchial diverticula in the subcarinal region: Their relation to airflow limitations

    Energy Technology Data Exchange (ETDEWEB)

    Higuchi, Takeshi; Takahashi, Naoya; Shiotani, Motoi; Sato, Suguru; Ohta, Atsushi; Maeda, Haruo; Nakajima, Haruhiko; Itoh, Kazuhiko; Tsukada, Hiroki (Department of Radiology, Respiratory Medicine, Niigata City General Hospital, Niigata-city, Niigata-ken (Japan)), Email: higuchi@hosp.niigata.niigata.jp

    2012-02-15

    Background. To date, bronchial diverticula have generally been treated as a pathological condition associated with chronic obstructive pulmonary disease (COPD), although only a limited amount of published information is available on the relationship between bronchial diverticula as depicted by multidetector computed tomography (MDCT) and airflow limitations. Purpose. To evaluate the relationship between airflow limitations and main bronchial diverticula in the subcarinal region using spirometry and thin-section MDCT. Material and Methods. A total of 189 consecutive adult patients were retrospectively evaluated based on spirometry and thin-section MDCT of the chest. All examinations were performed at our institution between June and October 2008. The study group included 70 women and 119 men with a mean age of 65 years (range 19-86 years). The relationship between the FEV1% and bronchial diverticula in the subcarinal region was analyzed (Student's t-test). Results. The indications for conducting the examinations were pulmonary diseases (82 patients), cardiovascular diseases (22), extrapulmonary malignancies (74), and other conditions (11). A total of 84/189 (44.4%) patients showed bronchial diverticula, and the FEV{sub 1}% of 70/84 (83.3%) patients was above 70. The FEV{sub 1}% of patients with lesions ranged from 26.0 to 97.8 (mean 76.8), whereas the range was 28.1-94.4 (mean 73.7) in those without lesions. There was no significant association between the FEV{sub 1}% and the presence of subcarinal bronchial diverticula (P > 0.05). Conclusion. Our data demonstrate that thin-section chest CT commonly demonstrates main bronchial diverticula in the subcarinal region in patients without airflow limitations. We propose that the presence of a small number of tiny bronchial diverticula under the carina may not be a criterion for the diagnosis of COPD

  1. Interactions of bluff-body obstacles with turbulent airflows affecting evaporative fluxes from porous surfaces

    Science.gov (United States)

    Haghighi, Erfan; Or, Dani

    2015-11-01

    Bluff-body obstacles interacting with turbulent airflows are common in many natural and engineering applications (from desert pavement and shrubs over natural surfaces to cylindrical elements in compact heat exchangers). Even with obstacles of simple geometry, their interactions within turbulent airflows result in a complex and unsteady flow field that affects surface drag partitioning and transport of scalars from adjacent evaporating surfaces. Observations of spatio-temporal thermal patterns on evaporating porous surfaces adjacent to bluff-body obstacles depict well-defined and persistent zonation of evaporation rates that were used to construct a simple mechanistic model for surface-turbulence interactions. Results from evaporative drying of sand surfaces with isolated cylindrical elements (bluff bodies) subjected to constant turbulent airflows were in good agreement with model predictions for localized exchange rates. Experimental and theoretical results show persistent enhancement of evaporative fluxes from bluff-rough surfaces relative to smooth flat surfaces under similar conditions. The enhancement is attributed to formation of vortices that induce a thinner boundary layer over part of the interacting surface footprint. For a practical range of air velocities (0.5-4.0 m/s), low-aspect ratio cylindrical bluff elements placed on evaporating sand surfaces enhanced evaporative mass losses (relative to a flat surface) by up to 300% for high density of elements and high wind velocity, similar to observations reported in the literature. Concepts from drag partitioning were used to generalize the model and upscale predictions to evaporation from surfaces with multiple obstacles for potential applications to natural bluff-rough surfaces.

  2. Porous silver nanosheets: a novel sensing material for nanoscale and microscale airflow sensors.

    Science.gov (United States)

    Marzbanrad, Ehsan; Zhao, Boxin; Zhou, Norman Y

    2015-11-01

    Fabrication of nanoscale and microscale machines and devices is one of the goals of nanotechnology. For this purpose, different materials, methods, and devices should be developed. Among them, various types of miniaturized sensors are required to build the nanoscale and microscale systems. In this research, we introduce a new nanoscale sensing material, silver nanosheets, for applications such as nanoscale and microscale gas flow sensors. The silver nanosheets were synthesized through the reduction of silver ions by ascorbic acid in the presence of poly(methacrylic acid) as a capping agent, followed by the growth of silver in the shape of hexagonal and triangular nanoplates, and self-assembly and nanojoining of these structural blocks. At the end of this process, the synthesized nanosheets were floated on the solution. Then, their electrical and thermal stability was demonstrated at 120 °C, and their atmospheric corrosion resistance was clarified at the same temperature range by thermogravimetric analysis. We employed the silver nanosheets in fabricating airflow sensors by scooping out the nanosheets by means of a sensor substrate, drying them at room temperature, and then annealing them at 300 °C for one hour. The fabricated sensors were tested for their ability to measure airflow in the range of 1 to 5 ml min(-1), which resulted in a linear response to the airflow with a response and recovery time around 2 s. Moreover, continuous dynamic testing demonstrated that the response of the sensors was stable and hence the sensors can be used for a long time without detectable drift in their response.

  3. Effect of air-flow on the evaluation of refractive surgery ablation patterns.

    Science.gov (United States)

    Dorronsoro, Carlos; Schumacher, Silvia; Pérez-Merino, Pablo; Siegel, Jan; Mrochen, Michael; Marcos, Susana

    2011-02-28

    An Allegretto Eye-Q laser platform (Wavelight GmbH, Erlangen, Germany) was used to study the effect of air-flow speed on the ablation of artificial polymer corneas used for testing refractive surgery patterns. Flat samples of two materials (PMMA and Filofocon A) were ablated at four different air flow conditions. The shape and profile of the ablated surfaces were measured with a precise non-contact optical surface profilometer. Significant asymmetries in the measured profiles were found when the ablation was performed with the clinical air aspiration system, and also without air flow. Increasing air-flow produced deeper ablations, improved symmetry, and increased the repeatability of the ablation pattern. Shielding of the laser pulse by the plume of smoke during the ablation of plastic samples reduced the central ablation depth by more than 40% with no-air flow, 30% with clinical air aspiration, and 5% with 1.15 m/s air flow. A simple model based on non-inertial dragging of the particles by air flow predicts no central shielding with 2.3 m/s air flow, and accurately predicts (within 2 μm) the decrease of central ablation depth by shielding. The shielding effects for PMMA and Filofocon A were similar despite the differences in the ablation properties of the materials and the different full-shielding transmission coefficient, which is related to the number of particles ejected and their associated optical behavior. Air flow is a key factor in the evaluation of ablation patterns in refractive surgery using plastic models, as significant shielding effects are found with typical air-flow levels used under clinical conditions. Shielding effects can be avoided by tuning the air flow to the laser repetition rate.

  4. Characterizing and Analyzing the Airflow Field inside the Nozzle Block of Murata Vortex Spinning

    Institute of Scientific and Technical Information of China (English)

    ZHU Yun-de; ZOU Zhuan-yong; WU Jian-ming; XUE Wen-liang; CHENG Long-di

    2008-01-01

    A three-dimensional computational fluid dynamics model is developed by software Fluent 6.2, to simulate the flow field inside the nozzle block of the Murata vortex spinning.The flowing state and the distribution law of static pressure and velocity are characterized and analyzed.The relationship between the flowing state and the structure of the vortex spun yarn is also discussed.The research results can enhance the understanding of the yarn formation principle from viewpoint of the airflow field law inside the nozzle block of Murata vortex spinning.

  5. Pulmonary function impairment in patients with combined pulmonary fibrosis and emphysema with and without airflow obstruction

    Directory of Open Access Journals (Sweden)

    Kitaguchi Y

    2014-07-01

    Full Text Available Yoshiaki Kitaguchi,1,2 Keisaku Fujimoto,3 Masayuki Hanaoka,1 Takayuki Honda,4 Junichi Hotta,2 Jiro Hirayama2 1First Department of Internal Medicine, Shinshu University School of Medicine, Matsumoto, 2Department of Internal Medicine, Okaya City Hospital, Okaya, 3Department of Clinical Laboratory Sciences, 4Department of Laboratory Medicine, Shinshu University School of Medicine, Matsumoto, Japan Background: The syndrome of combined pulmonary fibrosis and emphysema (CPFE is a recently described entity associating upper-lobe emphysema and lower-lobe fibrosis. We sought to evaluate differences in pulmonary function between CPFE patients with and without airflow obstruction. Subjects and methods: Thirty-one CPFE patients were divided into two groups according to the presence or absence of irreversible airflow obstruction based on spirometry (forced expiratory volume in 1 second/forced vital capacity <70% following inhalation of a β2-agonist as follows: CPFE patients with airflow obstruction (CPFE OB+ group, n=11, and CPFE patients without airflow obstruction (CPFE OB– group, n=20. Pulmonary function, including respiratory impedance evaluated using impulse oscillometry and dynamic hyperinflation following metronome-paced incremental hyperventilation, was retrospectively analyzed in comparison with that observed in 49 chronic obstructive pulmonary disease (COPD patients (n=49. Results: In imaging findings, low-attenuation-area scores on chest high-resolution computed tomography, representing the degree of emphysema, were significantly lower in the CPFE OB– group than in the CPFE OB+ and COPD groups. In contrast, the severity of pulmonary fibrosis was greater in the CPFE OB– group than in the CPFE OB+ group. In pulmonary function, lung hyperinflation was not apparent in the CPFE OB– group. Impairment of diffusion capacity was severe in both the CPFE OB– and CPFE OB+ groups. Impulse oscillometry showed that respiratory resistance was not

  6. Using Coupled Energy, Airflow and IAQ Software (TRNSYS/CONTAM) to Evaluate Building Ventilation Strategies.

    Science.gov (United States)

    Dols, W Stuart; Emmerich, Steven J; Polidoro, Brian J

    2016-03-01

    Building energy analysis tools are available in many forms that provide the ability to address a broad spectrum of energy-related issues in various combinations. Often these tools operate in isolation from one another, making it difficult to evaluate the interactions between related phenomena and interacting systems, forcing oversimplified assumptions to be made about various phenomena that could otherwise be addressed directly with another tool. One example of such interdependence is the interaction between heat transfer, inter-zone airflow and indoor contaminant transport. In order to better address these interdependencies, the National Institute of Standards and Technology (NIST) has developed an updated version of the multi-zone airflow and contaminant transport modelling tool, CONTAM, along with a set of utilities to enable coupling of the full CONTAM model with the TRNSYS simulation tool in a more seamless manner and with additional capabilities that were previously not available. This paper provides an overview of these new capabilities and applies them to simulating a medium-size office building. These simulations address the interaction between whole-building energy, airflow and contaminant transport in evaluating various ventilation strategies including natural and demand-controlled ventilation. CONTAM has been in practical use for many years allowing building designers, as well as IAQ and ventilation system analysts, to simulate the complex interactions between building physical layout and HVAC system configuration in determining building airflow and contaminant transport. It has been widely used to design and analyse smoke management systems and evaluate building performance in response to chemical, biological and radiological events. While CONTAM has been used to address design and performance of buildings implementing energy conserving ventilation systems, e.g., natural and hybrid, this new coupled simulation capability will enable users to apply the

  7. Using Coupled Energy, Airflow and IAQ Software (TRNSYS/CONTAM) to Evaluate Building Ventilation Strategies

    Science.gov (United States)

    Dols, W. Stuart.; Emmerich, Steven J.; Polidoro, Brian J.

    2016-01-01

    Building energy analysis tools are available in many forms that provide the ability to address a broad spectrum of energy-related issues in various combinations. Often these tools operate in isolation from one another, making it difficult to evaluate the interactions between related phenomena and interacting systems, forcing oversimplified assumptions to be made about various phenomena that could otherwise be addressed directly with another tool. One example of such interdependence is the interaction between heat transfer, inter-zone airflow and indoor contaminant transport. In order to better address these interdependencies, the National Institute of Standards and Technology (NIST) has developed an updated version of the multi-zone airflow and contaminant transport modelling tool, CONTAM, along with a set of utilities to enable coupling of the full CONTAM model with the TRNSYS simulation tool in a more seamless manner and with additional capabilities that were previously not available. This paper provides an overview of these new capabilities and applies them to simulating a medium-size office building. These simulations address the interaction between whole-building energy, airflow and contaminant transport in evaluating various ventilation strategies including natural and demand-controlled ventilation. Practical Application CONTAM has been in practical use for many years allowing building designers, as well as IAQ and ventilation system analysts, to simulate the complex interactions between building physical layout and HVAC system configuration in determining building airflow and contaminant transport. It has been widely used to design and analyse smoke management systems and evaluate building performance in response to chemical, biological and radiological events. While CONTAM has been used to address design and performance of buildings implementing energy conserving ventilation systems, e.g., natural and hybrid, this new coupled simulation capability will

  8. The effects of pen partitions and thermal pig simulators on airflow in a livestock test room

    DEFF Research Database (Denmark)

    Bjerg, B.; Svidt, Kjeld; Zhang, G.

    2000-01-01

    partitions which divided the room into four equal-sized pens. The guiding plates beneath the ceiling were efficient in creating two-dimensional how in the occupied zone, but they increased the differences between measured and simulated air velocity close to the ceiling and close to the floor. Both...... measurements and CFD simulations showed that the introduction of pen partitions and thermal pig simulators reduced the air velocities in the occupied zone of the test room. Detailed geometric modelling of the animals might often be unnecessary for simulation of airflow in livestock rooms. This will especially...

  9. Numeric simulation of the upper airway structure and airflow dynamic characteristics after unilateral complete maxillary resection.

    Science.gov (United States)

    Qian, Yumei; Qian, Haixin; Wu, Yadong; Jiao, Ting

    2013-01-01

    This study investigated upper airway aerodynamic characteristics of patients who underwent maxillectomy using three-dimensional reconstruction and computational fluid dynamics. The results revealed the generation of low-velocity vortices throughout the entire maxillary defect during respiration. The nasal structure on the nonsurgical side changed postsurgically, possibly due to the pressure gradient between the defective and healthy side. The bilateral disturbed airflow patterns are believed to be the cause of common symptoms. The numeric simulation technique could be used as a potential method to understand upper airway morphology changes and respiratory functions, thus guiding the fabrication of prostheses.

  10. Morphological measurements in computed tomography correlate with airflow obstruction in chronic obstructive pulmonary disease: systematic review and meta-analysis

    Energy Technology Data Exchange (ETDEWEB)

    Xie, XueQian; Oudkerk, Matthijs; Vliegenthart, Rozemarijn [University of Groningen, University Medical Center Groningen, Center for Medical Imaging-North East Netherlands (CMI-NEN), Department of Radiology, Hanzeplein 1, P.O. Box 30.001, RB, Groningen (Netherlands); Jong, Pim A. de [University Medical Center Utrecht, University of Utrecht, Department of Radiology, Heidelberglaan 100, P.O. Box 85.500, CX, Utrecht (Netherlands); Wang, Ying [Tianjin Medical University General Hospital, Department of Radiology, Tianjin (China); Hacken, Nick H.T. ten [University of Groningen, University Medical Center Groningen, Department of Pulmonary Diseases, Hanzeplein 1, P.O. Box 30.001, RB, Groningen (Netherlands); Miao, Jingtao; Zhang, GuiXiang [Shanghai Jiao Tong University Affiliated First People' s Hospital, Department of Radiology, Shanghai (China); Bock, Geertruida H. de [University of Groningen, University Medical Center Groningen, Department of Epidemiology, Hanzeplein 1, P.O. Box 30.001, RB, Groningen (Netherlands)

    2012-10-15

    To determine the correlation between CT measurements of emphysema or peripheral airways and airflow obstruction in chronic obstructive pulmonary disease (COPD). PubMed, Embase and Web of Knowledge were searched from 1976 to 2011. Two reviewers independently screened 1,763 citations to identify articles that correlated CT measurements to airflow obstruction parameters of the pulmonary function test in COPD patients, rated study quality and extracted information. Three CT measurements were accessed: lung attenuation area percentage < -950 Hounsfield units, mean lung density and airway wall area percentage. Two airflow obstruction parameters were accessed: forced expiratory volume in the first second as percentage from predicted (FEV{sub 1} %pred) and FEV{sub 1} divided by the forced volume vital capacity. Seventy-nine articles (9,559 participants) were included in the systematic review, demonstrating different methodologies, measurements and CT airflow obstruction correlations. There were 15 high-quality articles (2,095 participants) in the meta-analysis. The absolute pooled correlation coefficients ranged from 0.48 (95 % CI, 0.40 to 0.54) to 0.65 (0.58 to 0.71) for inspiratory CT and 0.64 (0.53 to 0.72) to 0.73 (0.63 to 0.80) for expiratory CT. CT measurements of emphysema or peripheral airways are significantly related to airflow obstruction in COPD patients. CT provides a morphological method to investigate airway obstruction in COPD. (orig.)

  11. Effects of T-type Channel on Natural Convection Flows in Airflow-Path of Concrete Storage Cask

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Gyeong Uk; Kim, Hyoung Jin; Cho, Chun Hyung [KORAD, Daejeon (Korea, Republic of)

    2016-05-15

    The natural convection flows occurring in airflow-path are not simple due to complex flow-path configurations such as horizontal ducts, bent tube and annular flow-path. In addition, 16 T type channels acting as the shroud are attached vertically and 16 channel supporting the canister are attached horizontally on the inner surface of over-pack. The existence and nonexistence of T type channels have influences on the flow fields in airflow- path. The concrete storage cask has to satisfy the requirements to secure the thermal integrity under the normal, off-normal, and accident conditions. The present work is aiming at investigating the effects of T type channels on the flows in airflow-path under the normal conditions using the FLUENT 16.1 code. In order to focus on the flows in airflow-path, fuel regions in the canister are regarded as a single cylinder with heat sources and other components are fully modeled. This study investigated the flow fields in airflow-path of concrete storage cask, numerically. It was found that excepting for the fuel regions, maximum temperatures on other components were evaluated below allowable values. The location of maximum velocities depended on support channels, T type channels and flow area. The flows through air inlets developed along annular flow- path with forming the hot plumes. According to the existence and nonexistence of T type channel, the plume behavior showed the different flow patterns.

  12. EFFECTS OF TEMPERATURE AND AIRFLOW ON VOLUME DEVELOPMENT DURING BAKING AND ITS INFLUENCE ON QUALITY OF CAKE

    Directory of Open Access Journals (Sweden)

    NURUL ATIQAH SANI

    2014-06-01

    Full Text Available Volume and texture of cake are among the important parameters in measuring the quality of cake. The processing conditions play important roles in producing cakes of good quality. Recent studies focused more on the formulation and the manipulation of baking temperature, humidity and time instead of airflow condition. The objective of this study was to evaluate the effects of baking temperature and airflow on the volume development of cake and final cake quality such as volume development, firmness, springiness and moisture content. The cake was baked at three different temperatures (160oC, 170oC, and 180oC, and two different airflow conditions. Baking time, height changes of batter, texture and moisture content of cake were compared to identify the differences or similarities on the final product as the process conditions varied. Results showed that, airflow has more significant effects towards the product quality compared to baking temperature especially on baking time which was 25.58 - 45.16%, and the rate of height changes which was 0.7 mm/min. However, different baking temperatures had more significant effects towards volume expansion which was 2.86 – 8.37% and the springiness of cake which was 3.44% compared to airflow conditions.

  13. Fine-scale flight strategies of gulls in urban airflows indicate risk and reward in city living.

    Science.gov (United States)

    Shepard, Emily L C; Williamson, Cara; Windsor, Shane P

    2016-09-26

    Birds modulate their flight paths in relation to regional and global airflows in order to reduce their travel costs. Birds should also respond to fine-scale airflows, although the incidence and value of this remains largely unknown. We resolved the three-dimensional trajectories of gulls flying along a built-up coastline, and used computational fluid dynamic models to examine how gulls reacted to airflows around buildings. Birds systematically altered their flight trajectories with wind conditions to exploit updraughts over features as small as a row of low-rise buildings. This provides the first evidence that human activities can change patterns of space-use in flying birds by altering the profitability of the airscape. At finer scales still, gulls varied their position to select a narrow range of updraught values, rather than exploiting the strongest updraughts available, and their precise positions were consistent with a strategy to increase their velocity control in gusty conditions. Ultimately, strategies such as these could help unmanned aerial vehicles negotiate complex airflows. Overall, airflows around fine-scale features have profound implications for flight control and energy use, and consideration of this could lead to a paradigm-shift in the way ecologists view the urban environment.This article is part of the themed issue 'Moving in a moving medium: new perspectives on flight'.

  14. Fine-scale flight strategies of gulls in urban airflows indicate risk and reward in city living

    Science.gov (United States)

    Shepard, Emily L. C.

    2016-01-01

    Birds modulate their flight paths in relation to regional and global airflows in order to reduce their travel costs. Birds should also respond to fine-scale airflows, although the incidence and value of this remains largely unknown. We resolved the three-dimensional trajectories of gulls flying along a built-up coastline, and used computational fluid dynamic models to examine how gulls reacted to airflows around buildings. Birds systematically altered their flight trajectories with wind conditions to exploit updraughts over features as small as a row of low-rise buildings. This provides the first evidence that human activities can change patterns of space-use in flying birds by altering the profitability of the airscape. At finer scales still, gulls varied their position to select a narrow range of updraught values, rather than exploiting the strongest updraughts available, and their precise positions were consistent with a strategy to increase their velocity control in gusty conditions. Ultimately, strategies such as these could help unmanned aerial vehicles negotiate complex airflows. Overall, airflows around fine-scale features have profound implications for flight control and energy use, and consideration of this could lead to a paradigm-shift in the way ecologists view the urban environment. This article is part of the themed issue ‘Moving in a moving medium: new perspectives on flight’. PMID:27528784

  15. Low Cost Reversible Signed Comparator

    Directory of Open Access Journals (Sweden)

    Farah Sharmin

    2013-10-01

    Full Text Available Nowadays exponential advancement in reversible comp utation has lead to better fabrication and integration process. It has become very popular ove r the last few years since reversible logic circuit s dramatically reduce energy loss. It consumes less p ower by recovering bit loss from its unique input-o utput mapping. This paper presents two new gates called RC-I and RC-II to design an n-bit signed binary comparator where simulation results show that the p roposed circuit works correctly and gives significa ntly better performance than the existing counterparts. An algorithm has been presented in this paper for constructing an optimized reversible n-bit signed c omparator circuit. Moreover some lower bounds have been proposed on the quantum cost, the numbers of g ates used and the number of garbage outputs generated for designing a low cost reversible sign ed comparator. The comparative study shows that the proposed design exhibits superior performance consi dering all the efficiency parameters of reversible logic design which includes number of gates used, quantum cost, garbage output and constant inputs. This proposed design has certainly outperformed all the other existing approaches.

  16. Optimized AODV routing protocol based on reverse route search in leisure time and route learning%基于闲时逆寻和路由学习机制的优化AODV路由协议

    Institute of Scientific and Technical Information of China (English)

    杜青松; 朱江; 张尔扬

    2011-01-01

    对AODV协议在不同MANET网络环境中的性能缺陷进行了研究,提出了节点闲时反向路由搜索机制和邻居节点路由监听学习机制,并进一步提出了优化的AODV路由协议O-AODV.利用O-AODV协议在MANET网络中产生多个局部路由,从而增加网络中的路由冗余度,提高路由发现的效率,加快故障路由的本地修复.仿真实验结果表明,O-AODV协议提高了分组投递率,降低了端到端延时,有效地减少了网络中的重路由开销,在大规模和拓扑变化快的网络环境中优于AODV协议.%An optimized AODV routing protocol (0-AODV) which integrated RRSL mechanism (reverse route search in leisure time) and route learning mechanism was proposed. According to O-AODV, many local routes were produced in MANET and route redundancy was increased, therefore improved the efficiency of routing discovery, speeded up the local repair procedure of break routes, and decreased the overhead of route rediscovery. Simulation results indicate that O-AODV can improve packet delivery ratio and decrease the end-to-end packet delay, its performance is superior to AODV in large scale and fast changing MANET.

  17. Managing Reverse Logistics or Reversing Logistics Management?

    OpenAIRE

    Brito, Marisa

    2004-01-01

    textabstractIn the past, supply chains were busy fine-tuning the logistics from raw material to the end customer. Today an increasing flow of products is going back in the chain. Thus, companies have to manage reverse logistics as well.This thesis contributes to a better understanding of reverse logistics. The thesis brings insights on reverse logistics decision-making and it lays down theoretical principles for reverse logistics as a research field.In particular it puts together a framework ...

  18. Airflow characteristics and pollution distribution around a thermal manikin - Impact of specific personal and indoor environmental factors

    DEFF Research Database (Denmark)

    Licina, Dusan; Tham, Kwok Wai; Melikov, Arsen Krikor

    2016-01-01

    factors (room air temperature and ventilation flow) affect the airflow characteristic (velocity and temperature) around the thermal manikin and (2) to examine the pollution distribution within the convective boundary layer (CBL) around a thermal manikin and personal exposure to two types of airborne......This study presents a summary of experimental measurements on the airflow characteristics and pollution distribution around a non-breathing thermal manikin. The two objectives are: (1) to examine the extent to which personal (body posture, clothing insulation, table positioning) and environmental...... pollutants under factors that influence the CBL. The results show that the CBL generated by the thermal manikin influenced the airflow characteristics and pollution distribution in the breathing zone. Parameters such as room air temperature, body posture, clothing insulation, table positioning...

  19. WIND TUNNEL RESEARCH ON THE INFLUENCE OF ACTIVE AIRFLOW ON THE LIFT FORCE GENERATED BY THE AIRFOIL

    Directory of Open Access Journals (Sweden)

    Paweł Magryta

    2013-09-01

    Full Text Available The paper discusses the results of wind tunnel tests of airfoils with additional active airflow applied to their upper surfaces. These studies were carried out for a range of velocities up to 28 m/s in an open wind tunnel. Several types of airfoils selected for the examination feature different geometries and are widely applied in today’s aviation industry. The changes in the lift and drag force generated by these airfoils were recorded during the study. The test bench for the tests was equipped with a compressor and a vacuum pump to enable airflow through some holes on the airfoil upper surface. A rapid prototyping method and a 3D printer based on a powder printing technique were applied to print the airfoils. All of their surfaces were subject to surface grinding to smooth their external surfaces. The wind tunnel tests with and without active airflow applied to airfoils are summarised in the paper.

  20. A Numerical Model of Viscoelastic Layer Entrainment by Airflow in Cough

    Science.gov (United States)

    Mitran, Sorin M.

    2008-07-01

    Coughing is an alternative mode of ensuring mucus clearance in the lung when normal cilia induced flow breaks down. A numerical model of this process is presented with the following aspects. (1) A portion of the airway comprising the first three bronchus generations is modeled as radially reinforced elastic tubes. Elasticity equations are solved to predict airway deformation under effect of airway pressure. (2) The compressible, turbulent flow induced by rapid lung contraction is modeled by direct numerical simulation for Reynolds numbers in the range 5,000-10,000 and by Large Eddy Simulation for Reynolds numbers in the range 5,000-40,000. (3) A two-layer model of the airway surface liquid (ASL) covering the airway epithelial layer is used. The periciliary liquid (PCL) in direct contact with the epithelial layer is considered to be a Newtonian fluid. Forces modeling cilia beating can act upon this layer. The mucus layer between the PCL and the interior airflow is modeled as an Oldroyd-B fluid. The overall computation is a fluid-structure interaction simulation that tracks changes in ASL thickness and airway diameters that result from impulsive airflow boundary conditions imposed at bronchi ends. In particular, the amount of mucus that is evacuated from the system is computed as a function of cough intensity and mucus rheological properties.

  1. Effects of the ambient temperature on the airflow across a Caucasian nasal cavity.

    Science.gov (United States)

    Burgos, M A; Sanmiguel-Rojas, E; Martín-Alcántara, A; Hidalgo-Martínez, M

    2014-03-01

    We analyse the effects of the air ambient temperature on the airflow across a Caucasian nasal cavity under different ambient temperatures using CFD simulations. A three-dimensional nasal model was constructed from high-resolution computed tomography images for a nasal cavity from a Caucasian male adult. An exhaustive parametric study was performed to analyse the laminar-compressible flow driven by two different pressure drops between the nostrils and the nasopharynx, which induced calm breathing flow rates ࣈ 5.7 L/min and ࣈ 11.3 L/min. The inlet air temperature covered the range - 10(o) C ⩽ To ⩽50(o) C. We observed that, keeping constant the wall temperature of the nasal cavity at 37(o) C, the ambient temperature affects mainly the airflow velocity into the valve region. Surprisingly, we found an excellent linear relationship between the ambient temperature and the air average temperature reached at different cross sections, independently of the pressure drop applied. Finally, we have also observed that the spatial evolution of the mean temperature data along the nasal cavity can be collapsed for all ambient temperatures analysed with the introduction of suitable dimensionless variables, and this evolution can be modelled with the help of hyperbolic functions, which are based on the heat exchanger theory.

  2. Characteristics of aerodynamic sound sources generated by coiled wires in a uniform air-flow

    Science.gov (United States)

    Matsumoto, H.; Nishida, K.; Saitoh, K.

    2003-11-01

    This study deals experimentally with aerodynamic sounds generated by coiled wires in a uniform air-flow. The coiled wire is a model of the hair dryer's heater. In the experiment, the effects of the coil diameter D, wire diameter d and coil spacing s of the coiled wire on the aerodynamic sound have been clarified. The results of frequency analyses of the aerodynamic sounds show that an Aeolian sound is generated by the coiled wire, when s/d is larger than 1. Also the peak frequencies of Aeolian sounds generated by the coiled wires are higher than the ones generated by a straight cylinder having the same diameter d. To clarify the characteristics of the aerodynamic sound sources, the directivity of the aerodynamic sound generated by the coiled wire has been examined, and the coherent function between the velocity fluctuation around the coiled wire and the aerodynamic sound has been calculated. Moreover, the band overall value of coherent output power between the sound and the velocity fluctuations has been calculated. This method has clarified the sound source region of the Aeolian sound generated by the coiled wire. These results show that the Aeolian sound is generated by the arc part of the coiled wire, which is located in the upstream side of the air-flow.

  3. GOLD criteria overestimate airflow limitation in one-third of cases in the general Finnish population

    Directory of Open Access Journals (Sweden)

    Annette Kainu

    2016-10-01

    Full Text Available The Global Initiative for Chronic Obstructive Lung Disease (GOLD diagnostic criteria for chronic obstructive pulmonary disease (COPD use a fixed threshold of forced expiratory volume in 1 s (FEV1/forced vital capacity (FVC ratio (<0.70 in post-bronchodilation spirometry to indicate disease, which has been shown to underestimate and overestimate disease prevalence in younger and older adults, respectively, whilst criteria based on reference values have better accuracy. Differences in reference values have limited their use in international studies. However, the new Global Lung Function Initiative reference values (GLI2012 showed FEV1/FVC to be the least dependent on ethnicity. The aim of this study was to assess the prevalence of airflow limitation with GLI2012 and the degree of underdetection or overestimation related to the use of GOLD in the general population. A Finnish population sample of 1323 subjects (45% male with post-bronchodilation spirometry was studied. 80 subjects (6.0% and 55 subjects (4.2% were identified with airflow limitation with GOLD and GLI2012 criteria, respectively. The proportion of overestimation with GOLD increased with age from 25% of cases in 50-year-olds to 54% in 70-year-olds. Using z-score-based grading resulted in more dispersion in severity grading. In conclusion, the GOLD criteria cause a marked overestimation already from 50-year-olds and should be replaced with the GLI2012 criteria to improve diagnostic accuracy.

  4. Comparison of Respiratory Resistance Measurements Made with an Airflow Perturbation Device with Those from Impulse Oscillometry

    Directory of Open Access Journals (Sweden)

    J. Pan

    2013-01-01

    Full Text Available The airflow perturbation device (APD has been developed as a portable, easy to use, and a rapid response instrument for measuring respiratory resistance in humans. However, the APD has limited data validating it against the established techniques. This study used a mechanical system to simulate the normal range of human breathing to validate the APD with the clinically accepted impulse oscillometry (IOS technique. The validation system consisted of a sinusoidal flow generator with ten standardized resistance configurations that were shown to represent a total range of resistances from 0.12 to 0.95 kPa·L−1·s (1.2–9.7 cm H2O·L−1·s. Impulse oscillometry measurements and APD measurements of the mechanical system were recorded and compared at a constant airflow of 0.15 L·s−1. Both the IOS and APD measurments were accurate in assessing nominal resistance. In addition, a strong linear relationship was observed between APD measurements and IOS measurements (R2 = 0.999. A second series of measurements was made on ten human volunteers with external resistors added in their respiratory flow paths. Once calibrated with the mechanical system, the APD gave respiratory resistance measurements within 5% of IOS measurements. Because of their comparability to IOS measurements, APD measurements are shown to be valid representations of respiratory resistance.

  5. Comparison of upper airway respiratory resistance measurements with the esophageal pressure/airflow relationship during sleep.

    Science.gov (United States)

    Morgenstern, C; Schwaibold, M; Randerath, W; Bolz, A; Jané, R

    2011-01-01

    Measurement of upper airway resistance is of interest in sleep disordered breathing to estimate upper airway patency. Resistance is calculated with the airflow and respiratory effort signals. However, there is no consensus on a standard for upper airway resistance measurement. This study proposes a new benchmarking method to objectively compare different upper airway resistance measurement methods by objectively differentiating between breaths with inspiratory flow limitation (high resistance) and non-limited breaths (low resistance). Resistance was measured at peak-Pes, at peak-flow, at the linear portion of a polynomial equation, as an area comparative and as average resistance for an inspiration. A total of 20 patients with systematic, gold-standard esophageal pressure and nasal airflow acquisition were analyzed and 109,955 breaths were automatically extracted and evaluated. Relative resistance values in relationship to a reference resistance value obtained during wakefulness were also analyzed. The peak-Pes measurement method obtained the highest separation index with significant (p < 0.001) differences to the other methods, followed by the area comparative and the peak-flow methods. As expected, average resistances were significantly (p < 0.001) lower for the non-IFL than for the IFL group. Hence, we recommend employing the peak-Pes for accurate upper airway resistance estimation.

  6. Functional results in airflow improvement using a "flip-flap" alar technique: our experience.

    Science.gov (United States)

    Di Stadio, Arianna; Macro, Carlo

    2017-02-21

    Pinched nasal point can be arising as congenital malformation or as results of unsuccessfully surgery. The nasal valve alteration due to this problem is not only an esthetic problem but also a functional one because can modify the nasal airflow. Several surgical techniques were proposed in literature, we proposed our. The purpose of the study is the evaluation of nose airway flow using our flip-flap technique for correction of pinched nasal tip. This is a retrospective study conducted on twelve patients. Tip cartilages were remodeled by means of autologous alar cartilage grafting. The patients underwent a rhinomanometry pre and post-surgery to evaluate the results, and they performed a self-survey to evaluate their degree of satisfaction in term of airflow sensation improvement. Rhinomanometry showed improved nasal air flow (range from 25% to 75%) in all patients. No significant differences were showed between unilateral and bilateral alar malformation (p=0.49). Patient's satisfaction reached the 87.5%. Our analysis on the combined results (rhinomanometry and surveys) showed that this technique leads to improvement of nasal flow in patients affected by pinched nasal tip in all cases. Copyright © 2017 Associação Brasileira de Otorrinolaringologia e Cirurgia Cérvico-Facial. Published by Elsevier Editora Ltda. All rights reserved.

  7. Oscillatory Behavior of an Arc Airfoil in Low-Speed Airflow

    Science.gov (United States)

    Molki, Majid; Sattari, Negin

    2011-11-01

    A computational investigation is conducted to study the oscillatory behavior of an arc airfoil situated in low-speed airflow. The present work is relevant to situations where the conventional rigid airfoils do not apply, such as the flight of bats. The outcome of this study is also beneficial in the design of micro air vehicles with flexible wings. The computations are performed using a deforming mesh to accommodate the airfoil oscillations. An unsteady, spatially second-order algorithm is employed to capture the time-variations of the lift and drag coefficients. A key feature of the present work is the flow response to airfoil oscillations. Fast Fourier Transform was applied to various parameters of the flow. For certain values of angle of attack for the non-oscillating airfoil, the flow has a dominant frequency and a well-defined vortex shedding. For other values of angle of attack, the flow around the non-oscillating airfoil contains many frequencies and has complex vortical structures. However, the oscillating airfoil in all cases makes the flow field periodic with well-defined patterns of vortex shedding. In this work, the flux of vorticity from the airfoil surface into the airflow is computed and compared with the pressure gradient along the surface of the airfoil. Effects of oscillations on magnitude and behavior of aerodynamic forces are also studied.

  8. Detailed predictions of particle aspiration affected by respiratory inhalation and airflow

    Science.gov (United States)

    Inthavong, Kiao; Ge, Qin Jiang; Li, Xiang Dong; Tu, Ji Yuan

    2012-12-01

    The effects of air pollution found in the atmosphere and exposure to airborne particles are an important problem in the interest of public health. Exposure to contaminated air under different flow conditions is studied using the latest computational fluid dynamics models. For the first time the upper respiratory airway is integrated into a human body and placed inside a room, facing different airflow speeds (0.05-0.35 m s-1). It was found that the airflow streamlines diverged as it approached the human body, at the torso and accelerated upwards past the face and head before separating at the rear of the head, forming recirculating regions in the wake behind the body. Inhaled particles were tracked backwards to determine its origins. At a plane upstream from the face the locations of particles inhaled form a region known as the critical area, which is presented. This study establishes a better understanding of particle inhalability and provides a step towards a more holistic approach in determining inhalation toxicology effects of exposure to atmospheric particles.

  9. Description of the airflow produced by an air-assisted sprayer during pesticide applications to citrus

    Directory of Open Access Journals (Sweden)

    Ramon Salcedo

    2015-06-01

    Full Text Available Atmospheric drift of plant protection products is considered a major source of air pollution during pesticide applications. Citrus protection against pests and diseases usually requires application of these products using air-blast sprayers. Many authors have emphasized the influence of vegetation on the risk of spray drift. The aim of this work was to describe in detail how the airflow from an air-blast sprayer behaves when it reaches citrus trees and, in particular, the effect that the tree canopy has on this flow. Tests were conducted at a commercial citrus orchard with conventional machinery, placed parallel to a row of trees. Air velocity and direction was measured using a 3D ultrasonic anemometer in 225 points situated in three parallel planes perpendicular to the equipment. The stability of the airflow at each measuring point was studied and the mean velocities were graphically represented. Two vortexes, one behind the canopy, and another over the tree, have been deducted and never been reported before. Both may have an important influence on the trajectories of the sprayed droplets and, as a consequence, on the way in which plant protection products are diffused into the atmosphere. Observed turbulence intensities were higher than in similar experiments conducted in other tree crops, which may be attributable to the higher air volume generated by the machinery used for citrus protection and to the higher foliage density of citrus orchards.

  10. Mechanical Design of a Performance Test Rig for the Turbine Air-Flow Task (TAFT)

    Science.gov (United States)

    Xenofos, George; Forbes, John; Farrow, John; Williams, Robert; Tyler, Tom; Sargent, Scott; Moharos, Jozsef

    2003-01-01

    To support development of the Boeing-Rocketdyne RS84 rocket engine, a fill-flow, reaction turbine geometry was integrated into the NASA-MSFC turbine air-flow test facility. A mechanical design was generated which minimized the amount of new hardware while incorporating all test and instrUmentation requirements. This paper provides details of the mechanical design for this Turbine Air-Flow Task (TAFT) test rig. The mechanical design process utilized for this task included the following basic stages: Conceptual Design. Preliminary Design. Detailed Design. Baseline of Design (including Configuration Control and Drawing Revision). Fabrication. Assembly. During the design process, many lessons were learned that should benefit future test rig design projects. Of primary importance are well-defined requirements early in the design process, a thorough detailed design package, and effective communication with both the customer and the fabrication contractors. The test rig provided steady and unsteady pressure data necessary to validate the computational fluid dynamics (CFD) code. The rig also helped characterize the turbine blade loading conditions. Test and CFD analysis results are to be presented in another JANNAF paper.

  11. A Study of DC Surface Plasma Discharge in Absence of Free Airflow: Ionic Wind Velocity Profile

    Directory of Open Access Journals (Sweden)

    M. Rafika

    2009-01-01

    Full Text Available In our study we are interested with the DC (Direct Current electric corona discharge created between two wire electrodes. We present experimental results related to some electroaerodynamic actuators based on the DC corona discharge at the surface of a dielectric material. We used different geometrical forms of dielectric surface such as a plate, a cylinder and a wing of aircraft of type NACA 0015. We present the current density-electric filed characteristics for different cases in order to determine the discharge regimes. The corona discharge produces non-thermal plasma so that it is called plasma discharge. Plasma discharge creates a tangential ionic wind above the surface at the vicinity of the wall. We have measured the ionic wind induced by the corona discharge in absence of free external airflow, we give the ionic wind velocity profiles for different surface forms and we compare the actuators effect based on the span of the ionic wind velocity values. We notice that the maximum ionic wind velocity is obtained with the NACA profile, which shows the effectiveness of this actuator for the airflow control.

  12. An experimental study of a plasma actuator in absence of free airflow: Ionic wind velocity profile

    Science.gov (United States)

    Mestiri, R.; Hadaji, R.; Ben Nasrallah, S.

    2010-08-01

    In this study, we are interested in the direct current electrical corona discharge created between two wire electrodes. The experimental results are related to some electroaerodynamic actuators based on the direct current corona discharge at the surface of a dielectric material. Several geometrical forms are selected for the dielectric surface, such as a plate, a cylinder, and a NACA 0015 aircraft wing. The current density-electric field characteristics are presented for different cases in order to determine the discharge regimes. The corona discharge produces nonthermal plasma, so it is called plasma discharge. Plasma discharge creates a tangential ionic wind above the surface at the vicinity of the wall. The ionic wind induced by the corona discharge is measured in absence of free external airflow. The ionic wind velocity profiles and the maximum induced tangential force are given for different surface forms, so it is possible to compare the actuators effect based on the span of the ionic wind velocity and thrust values. The higher ionic wind velocity is obtained with the NACA profile, which shows the effectiveness of this actuator for the airflow control.

  13. Description of the airflow produced by an air-assisted sprayer during pesticide applications to citrus

    Energy Technology Data Exchange (ETDEWEB)

    Salcedo, R.; Garcera, C.; Granell, R.; Molto, E.; Chueca, P.

    2015-07-01

    Atmospheric drift of plant protection products is considered a major source of air pollution during pesticide applications. Citrus protection against pests and diseases usually requires application of these products using air-blast sprayers. Many authors have emphasized the influence of vegetation on the risk of spray drift. The aim of this work was to describe in detail how the airflow from an air-blast sprayer behaves when it reaches citrus trees and, in particular, the effect that the tree canopy has on this flow. Tests were conducted at a commercial citrus orchard with conventional machinery, placed parallel to a row of trees. Air velocity and direction was measured using a 3D ultrasonic anemometer in 225 points situated in three parallel planes perpendicular to the equipment. The stability of the airflow at each measuring point was studied and the mean velocities were graphically represented. Two vortexes, one behind the canopy, and another over the tree, have been deducted and never been reported before. Both may have an important influence on the trajectories of the sprayed droplets and, as a consequence, on the way in which plant protection products are diffused into the atmosphere. Observed turbulence intensities were higher than in similar experiments conducted in other tree crops, which may be attributable to the higher air volume generated by the machinery used for citrus protection and to the higher foliage density of citrus orchards. (Author)

  14. Impact of airflow interaction on inhaled air quality and transport of contaminants in rooms with personalized and total volume ventilation

    DEFF Research Database (Denmark)

    Melikov, Arsen Krikor; Cermak, Radim; Kovar, O.

    2003-01-01

    The impact of airflow interaction on inhaled air quality and transport of contaminants between occupants was studied in regard to pollution from floor covering, human bioeffluents and exhaled air, with combinations of two personalized ventilation systems (PV) with mixing and displacement ventilat......The impact of airflow interaction on inhaled air quality and transport of contaminants between occupants was studied in regard to pollution from floor covering, human bioeffluents and exhaled air, with combinations of two personalized ventilation systems (PV) with mixing and displacement...

  15. Managing Reverse Logistics or Reversing Logistics Management?

    NARCIS (Netherlands)

    M.P. de Brito (Marisa)

    2004-01-01

    textabstractIn the past, supply chains were busy fine-tuning the logistics from raw material to the end customer. Today an increasing flow of products is going back in the chain. Thus, companies have to manage reverse logistics as well.This thesis contributes to a better understanding of reverse

  16. Managing Reverse Logistics or Reversing Logistics Management?

    NARCIS (Netherlands)

    M.P. de Brito (Marisa)

    2004-01-01

    textabstractIn the past, supply chains were busy fine-tuning the logistics from raw material to the end customer. Today an increasing flow of products is going back in the chain. Thus, companies have to manage reverse logistics as well.This thesis contributes to a better understanding of reverse log

  17. Fanning the Optimal Breeze with an Abanico

    Science.gov (United States)

    Goon, Grace; Marthelot, Joel; Reis, Pedro; MIT EGS Lab Team

    Flexible hand-held fans, or abanicos, are universally employed as cooling devices that are both portable and sustainable. Their to and fro axial motion about one's hand generates an airflow that increases the evaporation rate near the skin and refreshes. We study this problem in the context of fluid-structure interaction, through precision model experiments. We first characterize the elastic properties of a semi-circular thin plates with various thickness and evaluate their aerodynamic performance in a custom built apparatus. The air velocity profile that results from the flapping motion of the fan is characterized for different driving conditions. A systematic variation of the geometric and elastic parameters, along with an exploration of the parameter space of the periodic driving motion (amplitude and frequency), allows us to establish optimal design and operational conditions for maximal output of the generated airflow, while minimizing the input power.

  18. Reversible Thermoset Adhesives

    Science.gov (United States)

    Mac Murray, Benjamin C. (Inventor); Tong, Tat H. (Inventor); Hreha, Richard D. (Inventor)

    2016-01-01

    Embodiments of a reversible thermoset adhesive formed by incorporating thermally-reversible cross-linking units and a method for making the reversible thermoset adhesive are provided. One approach to formulating reversible thermoset adhesives includes incorporating dienes, such as furans, and dienophiles, such as maleimides, into a polymer network as reversible covalent cross-links using Diels Alder cross-link formation between the diene and dienophile. The chemical components may be selected based on their compatibility with adhesive chemistry as well as their ability to undergo controlled, reversible cross-linking chemistry.

  19. Association of incidental emphysema with annual lung function decline and future development of airflow limitation

    Directory of Open Access Journals (Sweden)

    Koo HK

    2016-01-01

    Full Text Available Hyeon-Kyoung Koo,1 Kwang Nam Jin,2 Deog Kyeom Kim,3 Hee Soon Chung,3 Chang-Hoon Lee3,4 1Department of Internal Medicine, Division of Pulmonary and Critical Care Medicine, College of Medicine, Ilsan Paik Hospital, Inje University, Goyang-si, Gyeonggi-Do, 2Department of Radiology, Seoul Metropolitan Government – Seoul National University Boramae Medical Center, 3Department of Internal Medicine, Division of Pulmonary and Critical Care Medicine, Seoul Metropolitan Government-Seoul National University Boramae Medical Center, 4Department of Internal Medicine, Division of Pulmonary and Critical Care Medicine, Seoul National University College of Medicine, Seoul National University Hospital, Seoul, Republic of Korea Objectives: Emphysema is one of the prognostic factors for rapid lung function decline in patients with COPD, but the impact of incidentally detected emphysema on population without spirometric abnormalities has not been evaluated. This study aimed to determine whether emphysema detected upon computed tomography (CT screening would accelerate the rate of lung function decline and influence the possibility of future development of airflow limitation in a population without spirometric abnormalities.Materials and methods: Subjects who participated in a routine screening for health checkup and follow-up pulmonary function tests for at least 3 years between 2004 and 2010 were retrospectively enrolled. The percentage of low-attenuation area below −950 Hounsfield units (%LAA−950 was calculated automatically. A calculated value of %LAA−950 that exceeded 10% was defined as emphysema. Adjusted annual lung function decline was analyzed using random-slope, random-intercept mixed linear regression models.Results: A total of 628 healthy subjects within the normal range of spriometric values were included. Multivariable analysis showed that the emphysema group exhibited a faster decline in forced vital capacity (−33.9 versus −18.8

  20. Desert dune growth and development: measurements of airflow and morphological change

    Science.gov (United States)

    Baddock, Matthew; Wiggs, Giles; Nield, Joanna

    2017-04-01

    The early stages of dune development remain a poorly understood aspect of bedform evolution. Flow-form feedbacks, however, are recognised to be fundamental in driving bedform growth across different stages of dune development. Specifically, the growth of aeolian bedforms has been linked theoretically with the location of the maximum windspeed at a point upwind of the bedform crest. This upwind position of maximum velocity, combined with the relaxation length scale for sand transport (Lsat) allows sand deposition in the crestal region of dunes, a necessity for vertical growth of the dune body. To date, there has been only limited empirical evidence of this process on a small number of individual dunes. We present field data from the Skeleton Coast dunefield in Namibia on the morphological change of a suite of bedforms over the full range of dune development stages (i.e. sand patch, protodune, dome and barchan dune). Our investigations include measurements at both high-energy event timescales and over a multi-annual period. For the event-scale periods, near-surface airflow measurements have been undertaken coincident with high frequency surface change allowing the coupling of flow dynamics and morphological change to the stage of dune development. This paper will highlight the extent to which the crestal flow velocity patterns elucidate the distribution of erosion and deposition for the range bedform types. For example, the airflow over the protodune demonstrates the crest-upwind velocity shift coinciding with patterns of sediment deposition and vertical growth. Annual change of the established dunes (dome and barchan) reveals features maintaining their shape while migrating, while also increasing their overall sediment volume. While flow-form measurements indicate the importance of airflow dynamics in driving dune growth as observed over the short term, multi-year change reveals shrinkage of both the sand patch and protodune at our study site. Such long term

  1. Using aeroelastic structures with nonlinear switching electronics to increase potential energy yield in airflow: investigating analog control circuitry for automated peak detection

    Science.gov (United States)

    Mihalca, Alexander G.; Drosinos, Jonathan G.; Grayson, Malika; Garcia, Ephrahim

    2015-03-01

    Bending piezoelectric transducers have the ability to harvest energy from aeroelastic vibrations induced by the ambient airflow. Such harvesters can have useful applications in the operation of low power devices, and their relatively small size makes them ideal for use in urban environments over civil infrastructure. One of the areas of focus regarding piezoelectric energy harvesting is the circuit topology used to store the harvested power. This study aims to further investigate the increase in potential energy yield from the piezoelectric harvester by optimizing the circuitry connecting the piezoelectric transducer and the power storage interface. When compared to an optimal resistive load case, it has been shown that certain circuit topologies, specifically synchronized switching and discharging to a storage capacitor through an inductor (SSDCI), can increase the charging power by as much as 400% if the circuit is completely lossless. This paper proposes a strategy for making a self-sufficient SSDCI circuit capable of peak detection for the synchronized switching using analog components. Using circuit simulation software, the performance of this proposed self-sufficient circuit is compared to an ideal case, and the effectiveness of the self-sufficient circuit strategy is discussed based on these simulation results. Further investigation of a physical working model of the new circuit proposal will be developed and experimental results of the circuit's performance obtained and compared to the estimated performance from the model.

  2. Reverse logistics - a framework

    OpenAIRE

    Brito, Marisa; Dekker, Rommert

    2002-01-01

    textabstractIn this paper we define and compare Reverse Logistics definitions. We start by giving an understanding framework of Reverse Logistics: the why-what-how. By this means, we put in context the driving forces for Reverse Logistics, a typology of return reasons, a classification of products, processes and actors. In addition we provide a decision framework for Reverse Logistics and we present it according to long, medium and short term decisions, i.e. strategic-tactic-operational decis...

  3. 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.

  4. Parallelization of Reversible Ripple-carry Adders

    DEFF Research Database (Denmark)

    Thomsen, Michael Kirkedal; Axelsen, Holger Bock

    2009-01-01

    The design of fast arithmetic logic circuits is an important research topic for reversible and quantum computing. A special challenge in this setting is the computation of standard arithmetical functions without the generation of \\emph{garbage}. Here, we present a novel parallelization scheme...... wherein $m$ parallel $k$-bit reversible ripple-carry adders are combined to form a reversible $mk$-bit \\emph{ripple-block carry adder} with logic depth $\\mathcal{O}(m+k)$ for a \\emph{minimal} logic depth $\\mathcal{O}(\\sqrt{mk})$, thus improving on the $mk$-bit ripple-carry adder logic depth $\\mathcal......{O}(m\\cdot k)$. The underlying mechanisms of the parallelization scheme are formally proven correct. We also show designs for garbage-less reversible comparison circuits. We compare the circuit costs of the resulting ripple-block carry adder with known optimized reversible ripple-carry adders in measures...

  5. Reverse logistics - a framework

    NARCIS (Netherlands)

    M.P. de Brito (Marisa); R. Dekker (Rommert)

    2002-01-01

    textabstractIn this paper we define and compare Reverse Logistics definitions. We start by giving an understanding framework of Reverse Logistics: the why-what-how. By this means, we put in context the driving forces for Reverse Logistics, a typology of return reasons, a classification of product

  6. 42 CFR 84.155 - Airflow resistance test; Type C supplied-air respirator, continuous flow class and Type CE...

    Science.gov (United States)

    2010-10-01

    ... 42 Public Health 1 2010-10-01 2010-10-01 false Airflow resistance test; Type C supplied-air respirator, continuous flow class and Type CE supplied-air respirator; minimum requirements. 84.155 Section... CE supplied-air respirator; minimum requirements. The resistance to air flowing from the respirator...

  7. CITRIC-ACID COUGH THRESHOLD AND AIRWAY RESPONSIVENESS IN ASTHMATIC-PATIENTS AND SMOKERS WITH CHRONIC AIR-FLOW OBSTRUCTION

    NARCIS (Netherlands)

    AUFFARTH, B; DEMONCHY, JGR; VANDERMARK, TW; POSTMA, DS; KOETER, GH

    1991-01-01

    The relation between citric acid cough threshold and airway hyperresponsiveness was investigated in 11 non-smoking patients with allergic asthma (mean FEV1 94% predicted) and 25 non-atopic smokers with chronic airflow obstruction (mean FEV1 65% predicted). Cough threshold was determined on two occas

  8. 42 CFR 84.156 - Airflow resistance test; Type C supplied-air respirator, demand class; minimum requirements.

    Science.gov (United States)

    2010-10-01

    ... C supplied-air respirator, demand class; minimum requirements. (a) Inhalation resistance shall not... 42 Public Health 1 2010-10-01 2010-10-01 false Airflow resistance test; Type C supplied-air respirator, demand class; minimum requirements. 84.156 Section 84.156 Public Health PUBLIC HEALTH SERVICE...

  9. 42 CFR 84.157 - Airflow resistance test; Type C supplied-air respirator, pressure-demand class; minimum...

    Science.gov (United States)

    2010-10-01

    ... respirator, pressure-demand class; minimum requirements. 84.157 Section 84.157 Public Health PUBLIC HEALTH... ACTIVITIES APPROVAL OF RESPIRATORY PROTECTIVE DEVICES Supplied-Air Respirators § 84.157 Airflow resistance test; Type C supplied-air respirator, pressure-demand class; minimum requirements. (a) The...

  10. The effects of simultaneous electrophoresis and thermophoresis on particulate contamination of an inverted EUVL photomask surface in parallel airflow

    Science.gov (United States)

    Lee, Handol; Yook, Se-Jin; Young Han, Seog

    2012-10-01

    The combined influences of electrophoresis and thermophoresis on particle deposition on the inverted critical surface of a flat plate in parallel airflow were investigated by employing the statistical Lagrangian particle tracking approach in an effort to assess the degree of particulate contamination of EUVL photomasks during horizontal transport in cleanroom environments. The numerical method was validated through the comparison with the experimental data, found in the literature, about particle deposition velocity onto a wafer in vertical airflow with and without electrophoresis or thermophoresis. In addition, the validation of the present model was performed via the comparison with the theoretical prediction of particle deposition velocity onto a flat plate under no phoretic forces in parallel airflow. Then, the particle deposition velocity onto the face-down surface of a flat plate in parallel airflow was obtained by varying the temperature of the inverted critical surface in different strengths of uniform electric fields. Injected particles were assumed to be charged with -1 , 0, or +1 elementary unit of charge, in order to consider attractive or repulsive electric force. The degree of particulate contamination of the inverted critical surface was found to be significantly influenced by the combination of electrophoretic and thermophoretic effects.

  11. Morphological measurements in computed tomography correlate with airflow obstruction in chronic obstructive pulmonary disease : systematic review and meta-analysis

    NARCIS (Netherlands)

    Xie, X.Q.; de Jong, P.A.; Oudkerk, M.; Wang, Y.; ten Hacken, N.H.T.; Miao, J.T.; Zhang, GuiXiang; de Bock, G.H.; Vliegenthart, R.

    2012-01-01

    To determine the correlation between CT measurements of emphysema or peripheral airways and airflow obstruction in chronic obstructive pulmonary disease (COPD). PubMed, Embase and Web of Knowledge were searched from 1976 to 2011. Two reviewers independently screened 1,763 citations to identify

  12. Numerical simulation of soft palate movement and airflow in human upper airway by fluid-structure interaction method

    Science.gov (United States)

    Sun, Xiuzhen; Yu, Chi; Wang, Yuefang; Liu, Yingxi

    2007-08-01

    In this paper, the authors present airflow field characteristics of human upper airway and soft palate movement attitude during breathing. On the basis of the data taken from the spiral computerized tomography images of a healthy person and a patient with Obstructive Sleep Apnea-Hypopnea Syndrome (OSAHS), three-dimensional models of upper airway cavity and soft palate are reconstructed by the method of surface rendering. Numerical simulation is performed for airflow in the upper airway and displacement of soft palate by fluid-structure interaction analysis. The reconstructed three-dimensional models precisely preserve the original configuration of upper airways and soft palate. The results of the pressure and velocity distributions in the airflow field are quantitatively determined, and the displacement of soft palate is presented. Pressure gradients of airway are lower for the healthy person and the airflow distribution is quite uniform in the case of free breathing. However, the OSAHS patient remarkably escalates both the pressure and velocity in the upper airway, and causes higher displacement of the soft palate. The present study is useful in revealing pathogenesis and quantitative mutual relationship between configuration and function of the upper airway as well as in diagnosing diseases related to anatomical structure and function of the upper airway.

  13. NOCTURNAL AIR-FLOW OBSTRUCTION, HISTAMINE, AND THE AUTONOMIC CENTRAL-NERVOUS-SYSTEM IN CHILDREN WITH ALLERGIC-ASTHMA

    NARCIS (Netherlands)

    VANAALDEREN, WMC; POSTMA, DS; KOETER, GH; KNOL, K

    A study was carried out to investigate whether an imbalance in the autonomic nervous system or release of histamine, or both, is responsible for the nocturnal increase in airflow obstruction in asthmatic children. The study comprised 18 children with allergic asthma,nine with (group 1) and nine

  14. Numerical simulation of soft palate movement and airflow in human upper airway by fluid-structure interaction method

    Institute of Scientific and Technical Information of China (English)

    Xiuzhen Sun; Chi Yu; Yuefang Wang; Yingxi Liu

    2007-01-01

    In this paper, the authors present airflow field characteristics of human upper airway and soft palate move-ment attitude during breathing. On the basis of the data taken from the spiral computerized tomography images of a healthy person and a patient with Obstructive Sleep Apnea-Hypopnea Syndrome (OSAHS), three-dimensional models of upper air-way cavity and soft palate are reconstructed by the method of surface rendering. Numerical simulation is performed for airflow in the upper airway and displacement of soft palate by fluid-structure interaction analysis. The reconstructed three-dimensional models precisely preserve the original config-uration of upper airways and soft palate. The results of the pressure and velocity distributions in the airflow field are quantitatively determined, and the displacement of soft palate is presented. Pressure gradients of airway are lower for the healthy person and the airflow distribution is quite uniform in the case of free breathing. However, the OSAHS patient remarkably escalates both the pressure and velocity in the upper airway, and causes higher displacement of the soft palate. The present study is useful in revealing pathogenesis and quantitative mutual relationship between configuration and function of the upper airway as well as in diagnosing diseases related to anatomical structure and function of the upper airway.

  15. CITRIC-ACID COUGH THRESHOLD AND AIRWAY RESPONSIVENESS IN ASTHMATIC-PATIENTS AND SMOKERS WITH CHRONIC AIR-FLOW OBSTRUCTION

    NARCIS (Netherlands)

    AUFFARTH, B; DEMONCHY, JGR; VANDERMARK, TW; POSTMA, DS; KOETER, GH

    The relation between citric acid cough threshold and airway hyperresponsiveness was investigated in 11 non-smoking patients with allergic asthma (mean FEV1 94% predicted) and 25 non-atopic smokers with chronic airflow obstruction (mean FEV1 65% predicted). Cough threshold was determined on two

  16. Using a Swinging Vane Anemometer to Measure Airflow. Module 14. Vocational Education Training in Environmental Health Sciences.

    Science.gov (United States)

    Consumer Dynamics Inc., Rockville, MD.

    This module, one of 25 on vocational education training for careers in environmental health occupations, contains self-instructional materials on using a swinging vane anemometer to measure airflow. Following guidelines for students and instructors and an introduction that explains what the student will learn are three lessons: (1) naming each…

  17. Genome-wide association studies identify CHRNA5/3 and HTR4 in the development of airflow obstruction

    NARCIS (Netherlands)

    Wilk, Jemma B; Shrine, Nick R G; Loehr, Laura R; Zhao, Jing Hua; Manichaikul, Ani; Lopez, Lorna M; Smith, Albert Vernon; Heckbert, Susan R; Smolonska, Joanna; Tang, Wenbo; Loth, Daan W; Curjuric, Ivan; Hui, Jennie; Cho, Michael H; Latourelle, Jeanne C; Henry, Amanda P; Aldrich, Melinda; Bakke, Per; Beaty, Terri H; Bentley, Amy R; Borecki, Ingrid B; Brusselle, Guy G; Burkart, Kristin M; Chen, Ting-hsu; Couper, David; Crapo, James D; Davies, Gail; Dupuis, Josée; Franceschini, Nora; Gulsvik, Amund; Hancock, Dana B; Harris, Tamara B; Hofman, Albert; Imboden, Medea; James, Alan L; Khaw, Kay-Tee; Lahousse, Lies; Launer, Lenore J; Litonjua, Augusto; Liu, Yongmei; Lohman, Kurt K; Lomas, David A; Lumley, Thomas; Marciante, Kristin D; McArdle, Wendy L; Meibohm, Bernd; Morrison, Alanna C; Musk, Arthur W; Myers, Richard H; North, Kari E; Postma, Dirkje S; Psaty, Bruce M; Rich, Stephen S; Rivadeneira, Fernando; Rochat, Thierry; Rotter, Jerome I; Artigas, María Soler; Starr, John M; Uitterlinden, André G; Wareham, Nicholas J; Wijmenga, Cisca; Zanen, Pieter; Province, Michael A; Silverman, Edwin K; Deary, Ian J; Palmer, Lyle J; Cassano, Patricia A; Gudnason, Vilmundur; Barr, R Graham; Loos, Ruth J F; Strachan, David P; London, Stephanie J; Boezen, Hendrika; Probst-Hensch, Nicole; Gharib, Sina A; Hall, Ian P; O'Connor, George T; Tobin, Martin D; Stricker, Bruno H

    2012-01-01

    RATIONALE: Genome-wide association studies (GWAS) have identified loci influencing lung function, but fewer genes influencing chronic obstructive pulmonary disease (COPD) are known. OBJECTIVES: Perform meta-analyses of GWAS for airflow obstruction, a key pathophysiologic characteristic of COPD asses

  18. Metamorphism during temperature gradient with undersaturated advective airflow in a snow sample

    Science.gov (United States)

    Ebner, Pirmin Philipp; Schneebeli, Martin; Steinfeld, Aldo

    2016-04-01

    Snow at or close to the surface commonly undergoes temperature gradient metamorphism under advective flow, which alters its microstructure and physical properties. Time-lapse X-ray microtomography is applied to investigate the structural dynamics of temperature gradient snow metamorphism exposed to an advective airflow in controlled laboratory conditions. Cold saturated air at the inlet was blown into the snow samples and warmed up while flowing across the sample with a temperature gradient of around 50 K m-1. Changes of the porous ice structure were observed at mid-height of the snow sample. Sublimation occurred due to the slight undersaturation of the incoming air into the warmer ice matrix. Diffusion of water vapor opposite to the direction of the temperature gradient counteracted the mass transport of advection. Therefore, the total net ice change was negligible leading to a constant porosity profile. However, the strong recrystallization of water molecules in snow may impact its isotopic or chemical content.

  19. Patient-specific modelling of pulmonary airflow using GPU cluster for the application in medical practice.

    Science.gov (United States)

    Miki, T; Wang, X; Aoki, T; Imai, Y; Ishikawa, T; Takase, K; Yamaguchi, T

    2012-01-01

    In this paper, we propose a novel patient-specific method of modelling pulmonary airflow using graphics processing unit (GPU) computation that can be applied in medical practice. To overcome the barriers imposed by computation speed, installation price and footprint to the application of computational fluid dynamics, we focused on GPU computation and the lattice Boltzmann method (LBM). The GPU computation and LBM are compatible due to the characteristics of the GPU. As the optimisation of data access is essential for the performance of the GPU computation, we developed an adaptive meshing method, in which an airway model is covered by isotropic subdomains consisting of a uniform Cartesian mesh. We found that 4(3) size subdomains gave the best performance. The code was also tested on a small GPU cluster to confirm its performance and applicability, as the price and footprint are reasonable for medical applications.

  20. A twin-type airflow pulse ionization chamber for continuous alpha-radioactivity monitoring in atmosphere

    Energy Technology Data Exchange (ETDEWEB)

    Kada, Wataru, E-mail: kada@nf.eie.eng.osaka-u.ac.j [Graduate School of Engineering, Osaka University, 2-1 Yamada-oka, Suita, Osaka 565-0871 (Japan); Dwaikat, Nidal; Datemichi, Jun; Sato, Fuminobu; Murata, Isao; Kato, Yushi; Iida, Toshiyuki [Graduate School of Engineering, Osaka University, 2-1 Yamada-oka, Suita, Osaka 565-0871 (Japan)

    2010-10-15

    A simple and inexpensive twin-type airflow pulse ionization chamber was developed for the continuous monitoring of alpha-radioactivity in atmosphere under high humidity condition. The symmetrical structure of the twin-type ionization chamber was effective in the improvement of the ratio of signal to noise in the measurement of pulses induced by alpha-rays. Outdoor alpha-ray measurement was well performed with this ionization chamber by applying sufficiently high bias voltage to the electrodes, except for at very high humidity conditions. It was confirmed that the declination of the counting efficiency due to wetting was easily recovered by the dry-up of the inside of the chamber. Alpha-radioactivity from radon and other alpha-emitting radionuclide in atmosphere was satisfactorily monitored by the detector.

  1. Simulation and analysis of airflow stability during fire in mine belt roadway

    Institute of Scientific and Technical Information of China (English)

    ZHANG Sheng-zhu; CHENG Wei-min; LI Qiu-jin; ZHANG Rui; LUO Chuan-long

    2010-01-01

    According to fluid dynamics analysis during the fire, the criteria k-ε two-equation model for solving three-dimensional turbulence was determined, the pollutants generated in the fire disaster were set by adopting Mixture multiphase flow, and the SIMPLE algorithm was used for solving on the basis of comprehensive consideration on the heat radiation and components transmission during fire. By simulating the airflow flowing state inside the tunnel during fire disaster of downward ventilation, drift ventilation, and ascensional ventilation, respectively, with regard to the actual situation of No.1, No.3, and No.5 belt roadway in Kongzhuang Coal Mine, the velocity vector distributions of pollutants under different inlet air volumes were obtained, and the damage degree and influential factors of disaster were also clear, which is helpful to control and avoid disaster during belt roadway fire.

  2. Characteristics of Turbulent Airflow Deduced from Rapid Surface Thermal Fluctuations: An Infrared Surface Anemometer

    Science.gov (United States)

    Aminzadeh, Milad; Breitenstein, Daniel; Or, Dani

    2017-07-01

    The intermittent nature of turbulent airflow interacting with the surface is readily observable in fluctuations of the surface temperature resulting from the thermal imprints of eddies sweeping the surface. Rapid infrared thermography has recently been used to quantify characteristics of the near-surface turbulent airflow interacting with the evaporating surfaces. We aim to extend this technique by using single-point rapid infrared measurements to quantify properties of a turbulent flow, including surface exchange processes, with a view towards the development of an infrared surface anemometer. The parameters for the surface-eddy renewal (α and β ) are inferred from infrared measurements of a single-point on the surface of a heat plate placed in a wind tunnel with prescribed wind speeds and constant mean temperatures of the surface. Thermally-deduced parameters are in agreement with values obtained from standard three-dimensional ultrasonic anemometer measurements close to the plate surface (e.g., α = 3 and β = 1/26 (ms)^{-1} for the infrared, and α = 3 and β = 1/19 (ms)^{-1} for the sonic-anemometer measurements). The infrared-based turbulence parameters provide new insights into the role of surface temperature and buoyancy on the inherent characteristics of interacting eddies. The link between the eddy-spectrum shape parameter α and the infrared window size representing the infrared field of view is investigated. The results resemble the effect of the sampling height above the ground in sonic anemometer measurements, which enables the detection of larger eddies with higher values of α . The physical basis and tests of the proposed method support the potential for remote quantification of the near-surface momentum field, as well as scalar-flux measurements in the immediate vicinity of the surface.

  3. Airflow limitation as a risk factor for low bone mineral density and hip fracture

    Science.gov (United States)

    Herland, Trine; Apalset, Ellen M; Eide, Geir Egil; Tell, Grethe S; Lehmann, Sverre

    2016-01-01

    Aim To investigate whether airflow limitation is associated with bone mineral density (BMD) and risk of hip fractures. Methods A community sample of 5,100 subjects 47–48 and 71–73 years old and living in Bergen was invited. Participants filled in questionnaires and performed a post-bronchodilator spirometry measuring forced expiratory volume in 1 second (FEV1) and forced vital capacity (FVC). All attendants were invited to have a BMD measurement of the hip. During 10 years of follow-up, information on death was collected from the Norwegian Cause of Death Registry, and incident hip fractures were registered from regional hospital records of discharge diagnoses and surgical procedure codes. Results The attendance rate was 69% (n=3,506). The prevalence of chronic obstructive pulmonary disease (COPD) (FEV1/FVC<0.7) was 9%. In multiple logistic regression, the lowest quartile of BMD versus the three upper was significantly predicted by FEV1/FVC<0.7 and FEV1% predicted (odds ratio [OR]: 1.58, 95% confidence interval [CI]: 1.11 to 2.25, and OR per increase of 10%: 0.92, 95% CI: 0.86 to 0.99, respectively). Hip fracture occurred in 126 (4%) participants. In a Cox regression analysis, FEV1% predicted was associated with a lowered risk of hip fracture (hazard ratio per increase of 10%: 0.89, 95% CI: 0.79 to 0.997). Conclusion Airflow limitation is positively associated with low BMD and risk of hip fracture in middle-aged and elderly. PMID:27733234

  4. The classical Starling resistor model often does not predict inspiratory airflow patterns in the human upper airway.

    Science.gov (United States)

    Owens, Robert L; Edwards, Bradley A; Sands, Scott A; Butler, James P; Eckert, Danny J; White, David P; Malhotra, Atul; Wellman, Andrew

    2014-04-15

    The upper airway is often modeled as a classical Starling resistor, featuring a constant inspiratory airflow, or plateau, over a range of downstream pressures. However, airflow tracings from clinical sleep studies often show an initial peak before the plateau. To conform to the Starling model, the initial peak must be of small magnitude or dismissed as a transient. We developed a method to simulate fast or slow inspirations through the human upper airway, to test the hypothesis that this initial peak is a transient. Eight subjects [4 obstructive sleep apnea (OSA), 4 controls] slept in an "iron lung" and wore a nasal mask connected to a continuous/bilevel positive airway pressure machine. Downstream pressure was measured using an epiglottic catheter. During non-rapid eye movement (NREM) sleep, subjects were hyperventilated to produce a central apnea, then extrathoracic pressure was decreased slowly (∼2-4 s) or abruptly (<0.5 s) to lower downstream pressure and create inspiratory airflow. Pressure-flow curves were constructed for flow-limited breaths, and slow vs. fast reductions in downstream pressure were compared. All subjects exhibited an initial peak and then a decrease in flow with more negative pressures, demonstrating negative effort dependence (NED). The rate of change in downstream pressure did not affect the peak to plateau airflow ratio: %NED 22 ± 13% (slow) vs. 20 ± 5% (fast), P = not significant. We conclude that the initial peak in inspiratory airflow is not a transient but rather a distinct mechanical property of the upper airway. In contrast to the classical Starling resistor model, the upper airway exhibits marked NED in some subjects.

  5. Optimization of extraction of soybean protein by mixed reverse micelles composing of SDS-tween 60/isooctane-octanol%SDS-Tween60混合反胶束体系萃取大豆蛋白工艺优化

    Institute of Scientific and Technical Information of China (English)

    李润洁; 布冠好; 陈复生; 徐卫河

    2013-01-01

    soybean protein was extracted by SDS(sodium dodecyl sulfonate)-tween 60 (polyoxyethylene(60)sorbitan monostearate)/isooctane-octanol mixed reverse micelles system with ultrasonic assisted. The effects of the concentration of SDS and tween 60,the ratio of SDS to tween 60,KCl concentration and pH of buffer,water content(W0),extraction temperature and time, adding amount of soybean powder on the forward extraction rates were investigated. Orthogonal experiment was designed to optimize the extraction process,the results showed that the optimum conditions of forward extraction were:the concentration of SDS and tween 60 was 0.10 g/mL,the ratio of SDS to tween 60 was 7∶3,KCl concentration 0.10 mol/L,pH 7,water content(W0)20, extraction temperature 35℃,the forward extraction rate was 89.46%±1.21%. Then,the effect of KCl concentration,pH,ethanol concentration on backward also be studied and the suitable condition is KCl concentration 1.4 mol/L,pH 8.5,the concentration of ethanol 15%,the backward extraction rate was 87.37%±1.64%,so,the whole extraction rate was 78.16%±1.98%.%以全脂大豆粉为原料,采用SDS(十二烷基硫酸钠)-Tween 60(聚氧乙烯失水山梨醇硬脂酸酯)/异辛烷-正辛醇形成混合反胶束体系,辅以超声波萃取大豆蛋白;研究两种表面活性剂总浓度和质量比、缓冲溶液KCl浓度和pH、W0、萃取温度和时间、大豆粉加入量等因素对大豆蛋白前萃率影响,及缓冲溶液KCl浓度、pH和乙醇加入量对大豆蛋白后萃率影响。通过正交试验优化萃取工艺,得到最优前萃取条件为:表面活性剂总浓度0.10 g/mL,质量比为7∶3、KCl浓度0.10 mol/L,pH 7、W020、萃取温度35℃;在此条件下,大豆蛋白前萃率为89.46%±1.21%。最优后萃取条件为:缓冲溶液KCl浓度1.4 mol/L、pH 8.5、乙醇加入量15%,大豆蛋白后萃率为87.37%±1.64%;总萃取率为78.16%±1.98%。

  6. Reversible cortical blindness: posterior reversible encephalopathy syndrome.

    Science.gov (United States)

    Bandyopadhyay, Sabyasachi; Mondal, Kanchan Kumar; Das, Somnath; Gupta, Anindya; Biswas, Jaya; Bhattacharyya, Subir Kumar; Biswas, Gautam

    2010-11-01

    Cortical blindness is defined as visual failure with preserved pupillary reflexes in structurally intact eyes due to bilateral lesions affecting occipital cortex. Bilateral oedema and infarction of the posterior and middle cerebral arterial territory, trauma, glioma and meningioma of the occipital cortex are the main causes of cortical blindness. Posterior reversible encephalopathy syndrome (PRES) refers to the reversible subtype of cortical blindness and is usually associated with hypertension, diabetes, immunosuppression, puerperium with or without eclampsia. Here, 3 cases of PRES with complete or partial visual recovery following treatment in 6-month follow-up are reported.

  7. Introduction to reversible computing

    CERN Document Server

    Perumalla, Kalyan S

    2013-01-01

    Few books comprehensively cover the software and programming aspects of reversible computing. Filling this gap, Introduction to Reversible Computing offers an expanded view of the field that includes the traditional energy-motivated hardware viewpoint as well as the emerging application-motivated software approach. Collecting scattered knowledge into one coherent account, the book provides a compendium of both classical and recently developed results on reversible computing. It explores up-and-coming theories, techniques, and tools for the application of rever

  8. Designing eco-effective reverse logistics networks

    NARCIS (Netherlands)

    Souza, De Vitor; Borsato, Milton; Bloemhof-Ruwaard, Jacqueline

    2016-01-01

    Reverse Logistics Networks (RLNs) have grown in importance after return policies became compulsory. Lately, questions have been raised whether they are as helpful to the environment as possible. Efforts have been conducted to optimize RLNs in terms of their eco-efficiency, minimizing costs and emiss

  9. Designing eco-effective reverse logistics networks

    NARCIS (Netherlands)

    Souza, De Vitor; Borsato, Milton; Bloemhof-Ruwaard, Jacqueline

    2016-01-01

    Reverse Logistics Networks (RLNs) have grown in importance after return policies became compulsory. Lately, questions have been raised whether they are as helpful to the environment as possible. Efforts have been conducted to optimize RLNs in terms of their eco-efficiency, minimizing costs and

  10. Chronic airflow limitation in a rural Indian population: etiology and relationship to body mass index

    Directory of Open Access Journals (Sweden)

    Chakrabarti B

    2011-10-01

    Full Text Available Biswajit Chakrabarti1, Sabita Purkait2, Punyabrata Gun2, Vicky C Moore3, Samadrita Choudhuri4, MJ Zaman5,6, Christopher J Warburton1, Peter MA Calverley7, Rahul Mukherjee3 1Aintree Chest Centre, University Hospital Aintree, Liverpool, UK; 2Moitri Swasthya Kendra, Shramajibi Swasthya Udyog, Chengail, West Bengal, India; 3Department of Respiratory Medicine and Physiology, Birmingham Heartlands Hospital, Birmingham, UK; 4National Medical College, Birgunj, Nepal; 5Department of Epidemiology and Public Health, University College, London, UK; 6The George Institute for Global Health, Sydney, Australia; 7Clinical Sciences Centre, University Hospital Aintree, Liverpool, UK Purpose: Respiratory conditions remain a source of morbidity globally. As such, this study aimed to explore factors associated with the development of airflow obstruction (AFO in a rural Indian setting and, using spirometry, study whether underweight is linked to AFO. Methods: Patients > 35 years old attending a rural clinic in West Bengal, India, took a structured questionnaire, had their body mass index (BMI measured, and had spirometry performed by an ancillary health care worker. Results: In total, 416 patients completed the study; spirometry was acceptable for analysis of forced expiratory volume in 1 second in 286 cases (69%; 16% were noted to exhibit AFO. Factors associated with AFO were: increasing age (95% confidence interval (CI 0.004–0.011; P = 0.005, smoking history (95% CI 0.07–0.174; P = 0.006, male gender (95% CI 0.19–0.47; P = 0.012, reduced BMI (95% CI 0.19–0.65; P = 0.02, and occupation (95% CI 0.12–0.84; P = 0.08. The mean BMI in males who currently smoked (n = 60; 19.29 kg/m2; standard deviation [SD] 3.46 was significantly lower than in male never smokers (n = 33; 21.15 kg/m2 SD 3.38; P < 0.001. AFO was observed in 27% of subjects with a BMI <18.5 kg/m2, falling to 13% with a BMI ≥18.5 kg/m2 (P = 0.013. AFO was observed in 11% of housewives, 22% of farm

  11. Development of the Lung Function Questionnaire (LFQ to identify airflow obstruction

    Directory of Open Access Journals (Sweden)

    Barbara P Yawn

    2009-12-01

    Full Text Available Barbara P Yawn1, Douglas W Mapel2, David M Mannino3, Fernando J Martinez4, James F Donohue5, Nicola A Hanania6, Mark Kosinski7, Regina Rendas-Baum7, Matthew Mintz8, Steven Samuels9, Anand A Dalal10, On behalf of the Lung Function Questionnaire Working Group*1Olmsted Medical Center, Department of Research, Rochester, MN, USA; 2Lovelace Clinic Foundation, Albuquerque, NM, USA; 3University of Kentucky School of Medicine, Lexington, KT, USA; 4University of Michigan Health System, Ann Arbor, MI, USA; 5University of North Carolina School of Medicine, Chapel Hill, NC, USA; 6Baylor College of Medicine, Houston, TX, USA; 7QualityMetric, Inc., Lincoln, RI, USA; 8George Washington University School of Medicine, Washington, DC, USA; 9Indiana Internal Medicine Consultants, Greenwood, IN, USA; 10GlaxosmithKline, Research Triangle Park, NC, USA; *The Lung Function Questionnaire Working Group includes Barbara P Yawn, Douglas W Mapel, David M Mannino, Fernando Martinez, James Donohue, Nicola Hanania, Matthew Mintz, and Steven SamuelsObjective: To describe the item-selection and item-reduction for the Lung Function Questionnaire (LFQ, being developed to help clinicians identify patients appropriate for diagnostic evaluation for chronic obstructive pulmonary disease (COPD using spirometry.Methods: Item selection and reduction were based on information from 387 ≥40-year-old respondents to the third National Health and Nutrition Examination Survey who had self-reported chronic bronchitis. Item reduction involved stepwise logistic regression. The accuracy of the final subset of items for identifying individuals with airflow obstruction (forced expiratory volume in one second/forced vital capacity <0.70 versus those without it was assessed with receiver operating characteristic analysis. Content and face validity were assessed using focus groups of primary care physicians (n = 16 and interviews with COPD patients (n = 16.Results: The model with all five items (age

  12. Dynamics of near-surface electric discharges and mechanisms of their interaction with the airflow

    Science.gov (United States)

    Leonov, Sergey B.; Adamovich, Igor V.; Soloviev, Victor R.

    2016-12-01

    The main focus of the review is on dynamics and kinetics of near-surface discharge plasmas, such as surface dielectric barrier discharges sustained by AC and repetitively pulsed waveforms, pulsed DC discharges, and quasi-DC discharges, generated in quiescent air and in the airflow. A number of technical issues related to plasma flow control applications are discussed in detail, including discharge development via surface ionization waves, charge transport and accumulation on dielectric surface, discharge contraction, different types of flow perturbations generated by surface discharges, and effect of high-speed flow on discharge dynamics. In the first part of the manuscript, plasma morphology and results of electrical and optical emission spectroscopy measurements are discussed. Particular attention is paid to dynamics of surface charge accumulation and dissipation, both in diffuse discharges and during development of ionization instabilities resulting in discharge contraction. Contraction leads to significant increase of both the surface area of charge accumulation and the energy coupled to the plasma. The use of alternating polarity pulse waveforms accelerates contraction of surface dielectric barrier discharges and formation of filamentary plasmas. The second part discusses the interaction of discharge plasmas with quiescent air and the external airflow. Four major types of flow perturbations have been identified: (1) low-speed near-surface jets generated by electrohydrodynamic interaction (ion wind); (2) spanwise and streamwise vortices formed by both electrohydrodynamic and thermal effects; (3) weak shock waves produced by rapid heating in pulsed discharges on sub-microsecond time scale; and (4) near-surface localized stochastic perturbations, on sub-millisecond time, detected only recently. The mechanism of plasma-flow interaction remains not fully understood, especially in filamentary surface dielectric barrier discharges. Localized quasi-DC surface

  13. Reverse Core Engine with Thrust Reverser

    Science.gov (United States)

    Suciu, Gabriel L. (Inventor); Chandler, Jesse M. (Inventor)

    2017-01-01

    An engine system has a gas generator, a bi-fi wall surrounding at least a portion of the gas generator, a casing surrounding a fan, and the casing having first and second thrust reverser doors which in a deployed position abut each other and the bi-fi wall.

  14. TRANSISTOR IMPLEMENTATION OF REVERSIBLE PRT GATES

    Directory of Open Access Journals (Sweden)

    RASHMI S.B,

    2011-03-01

    Full Text Available Reversible logic has emerged as one of the most important approaches for power optimization with its application in low power VLSI design. Reversible or information lossless circuits have applications in nanotechnology, digital signal processing, communication, computer graphics and cryptography. They are also a fundamental requirement in the emerging field of quantum computing. In this paper, two newoptimized universal gates are proposed. One of them has an ability to operate as a reversible half adder and half subtractor imultaneously. Another one acts only as half adder with minimum transistor count. The reversible gates are evaluated in terms of number of transistor count, critical path, garbage outputs and one to one mapping. Here transistor implementation of the proposed gates is done by using Virtuoso tool of cadence. Based on the results of the analysis, some of the trade-offs are made in the design to improve the efficiency.

  15. Endoscopy findings affect subjective smell rehabilitation in post-laryngectomy patients using the nasal airflow-inducing manoeuvre.

    Science.gov (United States)

    Saedi, B; Razmpa, E; Nikjo, A; Ghalandarabadi, M; Ghadimi, H; Saidabadi, G

    2014-09-01

    To evaluate the characteristics of post-laryngectomy patients, including nasal endoscopy findings, that affect subjective smell improvement in the post-surgical period. Thirty patients who had undergone total laryngectomy participated in at least three sessions of a smell rehabilitation programme involving the nasal airflow-inducing manoeuvre, under the supervision of a speech-language pathologist. Patient characteristics and nasal endoscopy findings were evaluated. Participants experienced a mean improvement in sense of smell of 61 per cent (p effective method for improving smell perception and appetite in laryngectomy patients. There was no relationship between nasal endoscopy findings and outcome of the nasal airflow-inducing manoeuvre rehabilitation programme in our case series.

  16. Experimental and Numerical Study on Effects of Airflow and Aqueous Ammonium Temperature on Ammonia Mass Transfer Coefficient

    DEFF Research Database (Denmark)

    Rong, Li; Nielsen, Peter V.; Zhang, Guoqiang

    2010-01-01

    This paper reports the results of an investigation, based on fundamental fluid dynamics and mass transfer theory, carried out to obtain a general understanding of ammonia mass transfer from an emission surface. The effects of airflow and aqueous ammonium solution temperature on ammonia mass...... to investigate the surface concentration distribution and mass transfer coefficient at different temperatures and velocities for which the Reynolds number is from 1.36 × 104 to 5.43 × 104 (based on wind tunnel length). The surface concentration increases as velocity decreases and varies...... greatly along the airflow direction on the emission surface. The average mass transfer coefficient increases with higher velocity and turbulence intensity. However, the mass transfer coefficient estimated by CFD simulation is consistently larger than the calculated one by the method using dissociation...

  17. Voronoi polygons and self-consistent technique used to compute the airflow resistivity of randomly placed fibers in glass wool

    DEFF Research Database (Denmark)

    Tarnow, Viggo

    2002-01-01

    harmonic waves at low frequencies, the effective mass density is determined by the friction between air and fibers. The friction is described by the airflow resistivity, which depends on frequency, but for frequencies below 1000 Hz in glass wool with density 15–30 kg/m3, the resistivity to airflow......Sound in glass wool propagates mainly in the air between glass fibers. For sound waves considered here, the distance between fibers is much smaller than the wavelength. Therefore, the sound velocity and attenuation can be computed from an effective mass density and compressibility. For simple...... is constant, and equal to the constant current value. A computation of resistivity from fiber density and diameter will be presented for a model of glass wool that consists of parallel randomly placed fibers with equal diameters. The computation is based on Voronoi polygons, and the results will be compared...

  18. Airborne Contamination Control through Directed Airflow in the Exam Room: A Pilot Study Using a Membrane Diffuser

    Directory of Open Access Journals (Sweden)

    Debajyoti Pati

    2010-01-01

    Full Text Available Airborne infections have been documented as a major source of hospital acquired infection - one of the major concerns in healthcare delivery. An important factor contributing to airborne infection is cross contamination through air particulate dispersion as affected by the ventilation system design. Clean room technology (with membrane ceiling has been successfully used in technology and pharmaceutical industries to control airborne contamination. This study examined the performance of membrane ceiling technology in controlling air particulate dispersion in a mock-up exam room. It included both performance tests in a mock-up room and a simulation study of six different ventilation system designs using Computational Fluid Dynamics (CFD analysis. Findings suggest that a membrane diffuser directed airflow ventilation strategy occupying approximately 20% to 30% of the ceiling surface and placed over the patient in a contemporary sized exam room provides a less turbulent airflow pattern and less mixing of the air between the patient and others in the room.

  19. Experimental Study on Surface Dielectric Barrier Discharge Plasma Actuator with Different Encapsulated Electrode Widths for Airflow Control at Atmospheric Pressure

    Science.gov (United States)

    Qi, Xiaohua; Yang, Liang; Yan, Huijie; Jin, Ying; Hua, Yue; Ren, Chunsheng

    2016-10-01

    The surface dielectric barrier discharge (SDBD) plasma actuator has shown great promise as an aerodynamic flow control device. In this paper, the encapsulated electrode width of a SDBD actuator is changed to study the airflow acceleration behavior. The effects of encapsulated electrode width on the actuator performance are experimentally investigated by measuring the dielectric layer surface potential, time-averaged ionic wind velocity and thrust force. Experimental results show that the airflow velocity and thrust force increase with the encapsulated electrode width. The results can be attributed to the distinct plasma distribution at different encapsulated electrode widths. supported by National Natural Science Foundation of China (No. 11175037), National Natural Science Foundation for Young Scientists of China (No. 11305017) and Special Fund for Theoretical Physics (No. 11247239)

  20. 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.

  1. Clocked Thrust Reversers

    Science.gov (United States)

    Suciu, Gabriel L. (Inventor); Chandler, Jesse M. (Inventor)

    2017-01-01

    An aircraft includes a fuselage including a propulsion system supported within an aft portion. A thrust reverser is mounted proximate to the propulsion system for directing thrust in a direction to slow the aircraft. The thrust reverser directs thrust at an angle relative to a vertical plane to reduce interference on control surfaces and reduce generation of underbody lift.

  2. Atrioventricular Pacemaker Lead Reversal

    Directory of Open Access Journals (Sweden)

    Mehmet K Aktas, MD

    2007-01-01

    Full Text Available During cardiac surgery temporary epicardial atrial and ventricular leads are placed in case cardiac pacing is required postoperatively. We present the first reported series of patients with reversal of atrioventricular electrodes in the temporary pacemaker without any consequent deleterious hemodynamic effect. We review the electrocardiographic findings and discuss the findings that lead to the discovery of atrioventricular lead reversal.

  3. 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.

  4. Breathing life into dinosaurs: tackling challenges of soft-tissue restoration and nasal airflow in extinct species.

    Science.gov (United States)

    Bourke, Jason M; Porter, W M Ruger; Ridgely, Ryan C; Lyson, Tyler R; Schachner, Emma R; Bell, Phil R; Witmer, Lawrence M

    2014-11-01

    The nasal region plays a key role in sensory, thermal, and respiratory physiology, but exploring its evolution is hampered by a lack of preservation of soft-tissue structures in extinct vertebrates. As a test case, we investigated members of the "bony-headed" ornithischian dinosaur clade Pachycephalosauridae (particularly Stegoceras validum) because of their small body size (which mitigated allometric concerns) and their tendency to preserve nasal soft tissues within their hypermineralized skulls. Hypermineralization directly preserved portions of the olfactory turbinates along with an internal nasal ridge that we regard as potentially an osteological correlate for respiratory conchae. Fossil specimens were CT-scanned, and nasal cavities were segmented and restored. Soft-tissue reconstruction of the nasal capsule was functionally tested in a virtual environment using computational fluid dynamics by running air through multiple models differing in nasal soft-tissue conformation: a bony-bounded model (i.e., skull without soft tissue) and then models with soft tissues added, such as a paranasal septum, a scrolled concha, a branched concha, and a model combining the paranasal septum with a concha. Deviations in fluid flow in comparison to a phylogenetically constrained sample of extant diapsids were used as indicators of missing soft tissue. Models that restored aspects of airflow found in extant diapsids, such as appreciable airflow in the olfactory chamber, were judged as more likely. The model with a branched concha produced airflow patterns closest to those of extant diapsids. These results from both paleontological observation and airflow modeling indicate that S. validum and other pachycephalosaurids could have had both olfactory and respiratory conchae. Although respiratory conchae have been linked to endothermy, such conclusions require caution in that our re-evaluation of the reptilian nasal apparatus indicates that respiratory conchae may be more widespread

  5. Impact of body mass index on the predictive capacity of the COPD-6 device in the detection of airflow obstruction.

    Science.gov (United States)

    Figueira Gonçalves, Juan Marco; Pérez Méndez, Lina Inmaculada; Guzmán Sáenz, Cristina; Díaz Pérez, David; Viña Manrique, Pedro; Pedrero García, Arturo José

    2017-06-29

    The portable COPD-6 device has been validated as a screening tool for airflow obstruction through the quantification of the FEV1/FEV6 ratio. To date, however, the impact of body mass index (BMI) on its ability to predict airflow obstruction has not been evaluated. The aim of the study was to assess the predictive ability of COPD-6 to detect airflow obstruction based on the patient's BMI. A prospective and open cohort study in which 223 subjects who underwent conventional spirometry and COPD-6 were included. The area under the curve ROC (AUC) of FEV1/FEV6 was analysed in the detection of obstruction for all patients in addition to BMI (BMIBMI≥30kg/m(2)). Sensitivity and specificity, negative and positive predictive value as well as likelihood ratio were calculated to determine the cut-off point of COPD-6 FEV1/FEV6 ratio with greater predictive capacity. The COPD-6 allows ruling out airflow obstruction with AUC of the estimated ROC curve of 88% (95% CI 83-93). The cut-off point FEV1/FEV6 of 0.74-0.76 shows the best predictive capacity. However, this capacity is altered according to BMI with an increase in false positives in subjects with BMI≥30kg/ m(2) when using the same cut-off point for the whole sample. The choice of cut-off point FEV1/FEV6 for the detection of obstruction should be adjusted to the patient's BMI. Copyright © 2017 Elsevier España, S.L.U. All rights reserved.

  6. Diurnal and seasonal variation in air exchange rates and interzonal airflows measured by active and passive tracer gas in homes

    DEFF Research Database (Denmark)

    Bekö, Gabriel; Gustavsen, Sine; Frederiksen, Marie

    2016-01-01

    studied the pollutant distribution from one room (source room) and interzonal airflows across the dwellings. The air within a given floor was well mixed, with the average tracer gas concentration in the non-source rooms reaching approximately 70% of the source room concentration. There was less air...... movement between different floors. The position of the internal doors had a strong influence on the air movement....

  7. Towards Reversible Sessions

    Directory of Open Access Journals (Sweden)

    Francesco Tiezzi

    2014-06-01

    Full Text Available In this work, we incorporate reversibility into structured communication-based programming, to allow parties of a session to automatically undo, in a rollback fashion, the effect of previously executed interactions. This permits taking different computation paths along the same session, as well as reverting the whole session and starting a new one. Our aim is to define a theoretical basis for examining the interplay in concurrent systems between reversible computation and session-based interaction. We thus enrich a session-based variant of pi-calculus with memory devices, dedicated to keep track of the computation history of sessions in order to reverse it. We discuss our initial investigation concerning the definition of a session type discipline for the proposed reversible calculus, and its practical advantages for static verification of safe composition in communication-centric distributed software performing reversible computations.

  8. Schlieren imaging in a dielectric barrier discharge actuator for airflow control

    Science.gov (United States)

    Cristofolini, A.; Neretti, G.; Roveda, F.; Borghi, C. A.

    2012-02-01

    The operation of a surface dielectric barrier discharge actuator for airflow control has been experimentally investigated. The actuator is constituted by an electrode pair separated by a dielectric Teflon sheet. Several ac supply conditions have been utilized. An electrohydrodynamics interaction was induced in still air, and several fluid-dynamic regimes were obtained. Visualization of the plasma boundary layer during the discharge ignition phase and during the steady state regime was obtained by utilizing a Schlieren diagnostic technique. The vortex morphology and propagation velocities at all supply conditions utilized have been evaluated. Velocity profiles perpendicular to the actuator surface, obtained from Pitot tube measurements, and line intensity profiles, determined by means of Schlieren imaging, have been determined for the steady regime operation. The integral along a line perpendicular to the actuator surface of the light intensity of the Schlieren image has been calculated. The profile obtained is in good agreement with the Pitot velocity profile in all the supply conditions investigated. Numerical simulations were also performed. The calculations confirm the relation between the flow velocity distribution in the boundary layer and the gas density distribution, which is the cause of the Schlieren image.

  9. Numerical Analysis of Influencing Factors on Temperature Field and Airflow Distribution of the Displacement Ventilation System

    Institute of Scientific and Technical Information of China (English)

    NA Yanling; XING Jincheng; TU Guangbei; YU Songbo

    2005-01-01

    Indoor air quality and thermal comfort are important features of indoor environment. In this paper, a numerical simulation based on the k-ε model of CFD is used to analyze factors such as loading, exterior-protected construction, blowing-in rate that play an important role in the temperature field and airflow field of the displacement ventilation system. Exterior-protected construction has little influence on indoor temperature distribution of displacement ventilation systems and the influence is limited only in a small area near the external wall when the indoor heat source is the main cooling load.The height of a room has little influence on indoor temperature field, and the temperature gradient of active region is basically unchanged. In the system combined with a displacement ventilation system and a cooling system, the height also has little influence. When the cooling load is high,the indoor heat source creates a strong convective plume, which will make the average indoor air age lower, the ventilation efficiency higher and the elimination of pollutant easier. Air supply rate plays an important role in displacement ventilation systems. The increase of air supply rate that can be realized by increasing the air supply velocity and enlarging the area of air inlet will increase the mass capability of the system and diminish the vertical temperature gradient. From the comparison between simulations and experiments, it is concluded that this simulation are creditable.

  10. Coal and Gangue Underground Pneumatic Separation Effect Evaluation Influenced by Different Airflow Directions

    Directory of Open Access Journals (Sweden)

    Kehong Zheng

    2016-01-01

    Full Text Available Coal and gangue underground pneumatic separation is of key importance for green mining. Two kinds of arrangement schemes for high-pressure value used in pneumatic separation system are proposed in this study. Pneumatic separation effects are examined under different arrangement of high-pressure value. Here, theoretical pneumatic separation distance formulas of mineral particles affected by different airflow directions are derived and validated by a series of numerical simulations and orthogonal experiments. In the following analysis, the effects of gangue diameter (d, conveyor velocity (v0, and the height difference between conveyor belt and air nozzle (hp are mainly considered. The numerical simulation and experimental results indicate that pneumatic separation effects under the condition of u and v0 being in the opposite direction will be better than that of u and v0 being in the same direction. The pneumatic separation distance ΔS shows a decreasing trend with the increasing of the three factors. The study also shows that gangue diameter has the most significant influence on separation distance, followed by conveyor velocity v0 and height difference hp.

  11. Airflow analyses using thermal imaging in Arizona's Meteor Crater as part of METCRAX II

    Science.gov (United States)

    Grudzielanek, A. Martina; Vogt, Roland; Cermak, Jan; Maric, Mateja; Feigenwinter, Iris; Whiteman, C. David; Lehner, Manuela; Hoch, Sebastian W.; Krauß, Matthias G.; Bernhofer, Christian; Pitacco, Andrea

    2016-04-01

    In October 2013 the second Meteor Crater Experiment (METCRAX II) took place at the Barringer Meteorite Crater (aka Meteor Crater) in north central Arizona, USA. Downslope-windstorm-type flows (DWF), the main research objective of METCRAX II, were measured by a comprehensive set of meteorological sensors deployed in and around the crater. During two weeks of METCRAX II five infrared (IR) time lapse cameras (VarioCAM® hr research & VarioCAM® High Definition, InfraTec) were installed at various locations on the crater rim to record high-resolution images of the surface temperatures within the crater from different viewpoints. Changes of surface temperature are indicative of air temperature changes induced by flow dynamics inside the crater, including the DWF. By correlating thermal IR surface temperature data with meteorological sensor data during intensive observational periods the applicability of the IR method of representing flow dynamics can be assessed. We present evaluation results and draw conclusions relative to the application of this method for observing air flow dynamics in the crater. In addition we show the potential of the IR method for METCRAX II in 1) visualizing airflow processes to improve understanding of these flows, and 2) analyzing cold-air flows and cold-air pooling.

  12. 4DCT-based assessment of regional airflow distribution in healthy human lungs during tidal breathing

    Science.gov (United States)

    Choi, Jiwoong; Jahani, Nariman; Choi, Sanghun; Hoffman, Eric; Lin, Ching-Long

    2014-11-01

    Nonlinear dynamics of regional airflow distribution in healthy human lungs are studied with four-dimensional computed tomography (4DCT) quantitative imaging of four subjects. During the scanning session, subjects continuously breathed with tidal volumes controlled by the dual piston system. For each subject, 10 instantaneous volumetric image data sets (5 inspiratory and 5 expiratory phases) were reconstructed. A mass-preserving image registration was then applied to pairs of these image data to construct a breathing lung model. Regional distributions of local flow rate fractions are computed from time-varying local air volumes. The 4DCT registration-based method provides the link between local and global air volumes of the lung, allowing derivation of time-varying regional flow rates during the tidal breathing for computational fluid dynamics analysis. The local flow rate fraction remains greater in the lower lobes than in the upper lobes, being qualitatively consistent with those derived from three static CT (3SCT) images (Yin et al. JCP 2013). However, unlike 3SCT, the 4DCT data exhibit lung hysteresis between inspiration and expiration, providing more sensitive measures of regional ventilation and lung mechanics. NIH Grants U01-HL114494, R01-HL094315 and S10-RR022421.

  13. Numerical investigation of diffuser solidity effect on turbulent airflow and performance of the turbocharger compressor

    Directory of Open Access Journals (Sweden)

    Chehhat A.

    2016-12-01

    Full Text Available Low solidity diffuser in centrifugal compressors can achieve both high efficiency and wide operating ranges which is of great importance for turbocharger compressor. Low solidity is achieved by using a low chord to pitch ratio. In this work, a CFD simulation is carried out to examine the effect of solidity on airflow field of a turbocharger centrifugal compressor which consists of a simple-splitter impeller and a vaned diffuser. By changing the number of diffuser vanes while keeping the number of impeller blades constant, the solidity value of the diffuser is varied. The characteristics of the compressor are evaluated for 6, 8, 10 and 12 stator vanes which correspond to solidity of: 0.78, 1.04, 1.29 and 1.55, respectively. The spatial distribution of the pressure, velocity and turbulent kinetic energy show that the diffuser solidity has significant effect on flow field and compressor performance map. The compressor with a 6 vanes diffuser has higher efficiency and operates at a wider range of flow rate relative to that obtained with larger vans number. However a non-uniform flow at the compressor exit was observed with relatively high turbulent kinetic energy.

  14. Chronic Airflow Obstruction in a Black African Population: Results of BOLD Study, Ile-Ife, Nigeria.

    Science.gov (United States)

    Obaseki, Daniel O; Erhabor, Gregory E; Gnatiuc, Louisa; Adewole, Olufemi O; Buist, Sonia A; Burney, Peter G

    2016-01-01

    Global estimates suggest that Chronic Obstructive Pulmonary Disease (COPD) is emerging as a leading cause of death in developing countries but there are few spirometry-based general population data on its prevalence and risk factors in sub-Saharan Africa. We used the Burden of Obstructive Lung Disease (BOLD) protocol to select a representative sample of adults aged 40 years and above in Ile-Ife, Nigeria. All the participants underwent spirometry and provided information on smoking history, biomass and occupational exposures as well as diagnosed respiratory diseases and symptoms. Chronic Airflow Obstruction (CAO) was defined as the ratio of post-bronchodilator (BD) one second Forced Expiratory Volume (FEV1) to Forced Vital Capacity (FVC) below the lower limit of normal (LLN) of the population distribution for FEV1/FVC. The overall prevalence of obstruction (post-BD FEV1/FVC Ife, Nigeria and unrelated to biomass exposure. The key independent predictors are poor education, and previous diagnosis of tuberculosis or asthma.

  15. Airflow in a Multiscale Subject-Specific Breathing Human Lung Model

    CERN Document Server

    Choi, Jiwoong; Hoffman, Eric A; Tawhai, Merryn H; Lin, Ching-Long

    2013-01-01

    The airflow in a subject-specific breathing human lung is simulated with a multiscale computational fluid dynamics (CFD) lung model. The three-dimensional (3D) airway geometry beginning from the mouth to about 7 generations of airways is reconstructed from the multi-detector row computed tomography (MDCT) image at the total lung capacity (TLC). Along with the segmented lobe surfaces, we can build an anatomically-consistent one-dimensional (1D) airway tree spanning over more than 20 generations down to the terminal bronchioles, which is specific to the CT resolved airways and lobes (J Biomech 43(11): 2159-2163, 2010). We then register two lung images at TLC and the functional residual capacity (FRC) to specify subject-specific CFD flow boundary conditions and deform the airway surface mesh for a breathing lung simulation (J Comput Phys 244:168-192, 2013). The 1D airway tree bridges the 3D CT-resolved airways and the registration-derived regional ventilation in the lung parenchyma, thus a multiscale model. Larg...

  16. Design and development of desiccant seed dryer with airflow inversion and recirculation.

    Science.gov (United States)

    Gill, R S; Singh, Sukhmeet; Singh, Parm Pal

    2014-11-01

    A desiccant seed dryer has been developed to dry seed in deep bed at safe temperatures for good shelf life and germination. The dryer consists of two chambers viz., air conditioning control unit and seed drying chamber. It operates in seed drying mode and desiccant regeneration mode. It has provision for recirculation of the drying air to minimise the moisture removal from drying air. Also, it has provision of airflow inversion through deep seed bed for uniform drying. Moisture removal from drying air has been done using silica gel desiccant. Chilly 'Punjab Surakh', Chilly 'Punjab Guchhedaar', Paddy, Coriander, Fenugreek and Radish seeds was dried with hot air at 38 °C from initial moisture content of 26.9 to 5 % (wb) in 2 h, 46.52 to 4.19 % (wb) in 4.25 h, 13.3 to 2.61 % (wb) in 4 h, 13.4 to 10.08 % (wb) in 3 h, 12.4 to 8.22 % (wb) in 4¼ h and 10.6 to 6.08 % (wb) in 4 h respectively. The statistical analysis based on paired t-test showed that seed drying in this dryer has no adverse effect on seed germination.

  17. Ventilation Rates and Airflow Pathways in Patient Rooms: A Case Study of Bioaerosol Containment and Removal.

    Science.gov (United States)

    Mousavi, Ehsan S; Grosskopf, Kevin R

    2015-11-01

    Most studies on the transmission of infectious airborne disease have focused on patient room air changes per hour (ACH) and how ACH provides pathogen dilution and removal. The logical but mostly unproven premise is that greater air change rates reduce the concentration of infectious particles and thus, the probability of airborne disease transmission. Recently, a growing body of research suggests pathways between pathogenic source (patient) and control (exhaust) may be the dominant environmental factor. While increases in airborne disease transmission have been associated with ventilation rates below 2 ACH, comparatively less data are available to quantify the benefits of higher air change rates in clinical spaces. As a result, a series of tests were conducted in an actual hospital to observe the containment and removal of respirable aerosols (0.5-10 µm) with respect to ventilation rate and directional airflow in a general patient room, and, an airborne infectious isolation room. Higher ventilation rates were not found to be proportionately effective in reducing aerosol concentrations. Specifically, increasing mechanical ventilation from 2.5 to 5.5 ACH reduced aerosol concentrations only 30% on average. However, particle concentrations were more than 40% higher in pathways between the source and exhaust as was the suspension and migration of larger particles (3-10 µm) throughout the patient room(s). Computational analyses were used to validate the experimental results, and, to further quantify the effect of ventilation rate on exhaust and deposition removal in patient rooms as well as other particle transport phenomena.

  18. The relationship between nasal resistance to airflow and the airspace minimal cross-sectional area.

    Science.gov (United States)

    Garcia, Guilherme J M; Hariri, Benjamin M; Patel, Ruchin G; Rhee, John S

    2016-06-14

    The relationship between nasal resistance (R) and airspace minimal cross-sectional area (mCSA) remains unclear. After the introduction of acoustic rhinometry, many otolaryngologists believed that mCSA measurements would correlate with subjective perception of nasal airway obstruction (NAO), and thus could provide an objective measure of nasal patency to guide therapy. However, multiple studies reported a low correlation between mCSA and subjective nasal patency, and between mCSA and R. This apparent lack of correlation between nasal form and function has been a long-standing enigma in the field of rhinology. Here we propose that nasal resistance is described by the Bernoulli Obstruction Theory. This theory predicts two flow regimes. For mCSA>Acrit, the constriction is not too severe and there is not a tight coupling between R and mCSA. In contrast, when mCSAfluid dynamics (CFD) simulations were run in 3-dimensional models based on computed tomography scans of 15 NAO patients pre- and post-surgery (i.e., 60 unilateral nasal cavities). Airspace cross-sectional areas were quantified perpendicular to airflow streamlines. Our computational results are consistent with the theory. Given that in most people mCSA>Acrit (estimated to be 0.37cm(2)), this theory suggests that airway constrictions are rarely an exclusive contributor to nasal resistance, which may explain the weak correlation between mCSA and subjective nasal patency.

  19. Surgical clothing systems in laminar airflow operating room: a numerical assessment.

    Science.gov (United States)

    Sadrizadeh, Sasan; Holmberg, Sture

    2014-01-01

    This study compared two different laminar airflow distribution strategies - horizontal and vertical - and investigated the effectiveness of both ventilation systems in terms of reducing the sedimentation and distribution of bacteria-carrying particles. Three different staff clothing systems, which resulted in source strengths of 1.5, 4 and 5 CFU/s per person, were considered. The exploration was conducted numerically using a computational fluid dynamics technique. Active and passive air sampling methods were simulated in addition to recovery tests, and the results were compared. Model validation was performed through comparisons with measurement data from the published literature. The recovery test yielded a value of 8.1 min for the horizontal ventilation scenario and 11.9 min for the vertical ventilation system. Fewer particles were captured by the slit sampler and in sedimentation areas with the horizontal ventilation system. The simulated results revealed that under identical conditions in the examined operating room, the horizontal laminar ventilation system performed better than the vertical option. The internal constellation of lamps, the surgical team and objects could have a serious effect on the movement of infectious particles and therefore on postoperative surgical site infections.

  20. Numerical simulation of airway dimension effects on airflow patterns and odorant deposition patterns in the rat nasal cavity.

    Directory of Open Access Journals (Sweden)

    Zehong Wei

    Full Text Available The sense of smell is largely dependent on the airflow and odorant transport in the nasal cavity, which in turn depends on the anatomical structure of the nose. In order to evaluate the effect of airway dimension on rat nasal airflow patterns and odorant deposition patterns, we constructed two 3-dimensional, anatomically accurate models of the left nasal cavity of a Sprague-Dawley rat: one was based on high-resolution MRI images with relatively narrow airways and the other was based on artificially-widening airways of the MRI images by referencing the section images with relatively wide airways. Airflow and odorant transport, in the two models, were determined using the method of computational fluid dynamics with finite volume method. The results demonstrated that an increase of 34 µm in nasal airway dimension significantly decreased the average velocity in the whole nasal cavity by about 10% and in the olfactory region by about 12% and increased the volumetric flow into the olfactory region by about 3%. Odorant deposition was affected to a larger extent, especially in the olfactory region, where the maximum odorant deposition difference reached one order of magnitude. The results suggest that a more accurate nasal cavity model is necessary in order to more precisely study the olfactory function of the nose when using the rat.

  1. Large eddy simulation of the pharyngeal airflow associated with obstructive sleep apnea syndrome at pre and post-surgical treatment.

    Science.gov (United States)

    Mihaescu, Mihai; Mylavarapu, Goutham; Gutmark, Ephraim J; Powell, Nelson B

    2011-08-11

    Obstructive Sleep Apnea Syndrome (OSAS) is the most common sleep-disordered breathing medical condition and a potentially life-threatening affliction. Not all the surgical or non-surgical OSAS therapies are successful for each patient, also in part because the primary factors involved in the etiology of this disorder are not completely understood. Thus, there is a need for improving both diagnostic and treatment modalities associated with OSAS. A verified and validated (in terms of mean velocity and pressure fields) Large Eddy Simulation approach is used to characterize the abnormal pharyngeal airflow associated with severe OSAS and its interaction with the airway wall in a subject who underwent surgical treatment. The analysis of the unsteady flow at pre- and post-treatment is used to illustrate the airflow dynamics in the airway associated with OSAS and to reveal as well, the changes in the flow variables after the treatment. At pre-treatment, large airflow velocity and wall shear stress values were found at the obstruction site in all cases. Downstream of obstruction, flow separation generated flow recirculation regions and enhanced the turbulence production in the jet-like shear layers. The interaction between the generated vortical structures and the pharyngeal airway wall induced large fluctuations in the pressure forces acting on the pharyngeal wall. After the surgery, the flow field instabilities vanished and both airway resistance and wall shear stress values were significantly reduced.

  2. Impact of Airflow Limitation on Comorbidities and Postoperative Complications in Patients Undergoing Thoracic Surgery: A Retrospective Observational Study

    Science.gov (United States)

    Yoshimi, Kaku; Oh, Shiaki; Suzuki, Kenji; Kodama, Yuzo; Sekiya, Mitsuaki; MD, Yoshinosuke Fukuchi

    2016-01-01

    Purpose: To assess the frequency of airflow limitation (AFL), and the relationship between AFL and preoperative comorbidities or postoperative complications in patients who had undergone thoracic surgery. Methods: The medical records of patients who underwent non-cardiac thoracic surgery at our institution between August 1996 and January 2013 were retrospectively reviewed. On the basis of preoperative pulmonary function tests, patients were classified with those with FEV1/FVC <70% [AFL(+) group] or with FEV1/FVC ≥70% [AFL(−) group]. Patient characteristics, preoperative comorbidities and postoperative complications were compared between the groups. Results: Of the 3667 patients assessed, 738 (20.1%) were allocated to the AFL(+) group. AFL was an independent risk factor for three preoperative comorbidities: chronic obstructive pulmonary disease (odds ratio [OR]: 4.65), bronchial asthma (OR 4.30) and cardiac diseases (OR 1.41). Airflow limitation was also an independent risk factor for postoperative respiratory failure including long-term oxygen therapy (OR 2.14) and atelectasis (OR 1.90) in the patients who underwent lobectomy or partial resection of the lung. Conclusions: Our retrospective study revealed that careful attention needs to be paid to airflow limitation in patients who undergo non-cardiac thoracic surgery since it appears to be an important feature of preoperative comorbidities and to increase postoperative complications. PMID:26935262

  3. Three distinct surgical clothing systems in a turbulent mixing operating room equipped with mobile ultraclean laminar airflow screen

    DEFF Research Database (Denmark)

    Sadrizadeh, Sasan; Holmberg, Sture; Nielsen, Peter Vilhelm

    2016-01-01

    Two types of mobile screens producing ultraclean local laminar airflow were investigated as an addition to turbulent mixing operating room ventilation. The exploration was carried out numerically using computational fluid dynamics. Surface and volumetric particle counts were simulated on the oper......Two types of mobile screens producing ultraclean local laminar airflow were investigated as an addition to turbulent mixing operating room ventilation. The exploration was carried out numerically using computational fluid dynamics. Surface and volumetric particle counts were simulated...... on the operating and instrument tables with and without the additional mobile airflow screen. Three different source strengths (the mean bacteria-carrying particle value emitted from one person per second) due to staff clothing variety were considered. Model validation was performed through result comparisons...... with experimental data from the literature. Results confirmed that the mobile screen units reduced the airborne bacteria to an acceptable level for infection-prone surgeries. No significant particle concentration differences existed in the periphery of the operating room. Lower source strength resulting from...

  4. 基于退货背景的网上购物的逆向物流优化%Optimization of Reverse Logistics under Return Policy in Online Shopping

    Institute of Scientific and Technical Information of China (English)

    张健

    2013-01-01

    In this paper, on the basis of a brief introduction of reverse logistics, we analyzed the occurrence of reverse logistics in return of products purchased through online shopping caused by commodity imperfection, service deficiency, and change of consumer willingness. On such basis, we discussed the existing problems on the levels of appearance restoration, logistics expense, logistics method, and risk of damage and then proposed the countermeasures to develop reverse logistics under the current return policy on the dimensions of quality enhancement, notification rules, logistics cooperation, reinforcement of supervision and insurance of return cost. At the end, we analyzed the feasibility of launching the reverse logistics insurance in the online shopping field.%在简要介绍逆向物流的基础上,着重从商品瑕疵、服务缺陷和意愿改变三个方面,剖析了退货背景下逆向物流产生的原因.在此基础上,从恢复原貌、物流费用、物流方式和损毁风险四个层面探讨了退货背景下逆向物流存在的问题,进而从提升品质、告知规则、物流合作、加强监管和退运保险五个纬度重点论述了退货背景下逆向物流发展的对策,并在对网购领域逆向物流保险的可行性进行了分析.

  5. Inflammatory and immunological profiles in patients with COPD: relationship with FEV 1 reversibility

    Science.gov (United States)

    Queiroz, Cleriston Farias; Lemos, Antonio Carlos Moreira; Bastos, Maria de Lourdes Santana; Neves, Margarida Célia Lima Costa; Camelier, Aquiles Assunção; Carvalho, Natália Barbosa; de Carvalho, Edgar Marcelino

    2016-01-01

    ABSTRACT Objective: To determine whether COPD severity correlates with sputum cell counts, atopy, and asthma. Methods: This was a cross-sectional study involving 37 patients with COPD and 22 healthy subjects with normal lung function (controls). Sputum cell counts were determined by microscopy after centrifugation of samples. Skin prick tests were performed, and serum cytokines were determined by ELISA. Results: Patients were stratified by bronchodilator response: a non-reversible airflow limitation (nonRAL) group comprised 24 patients showing no significant post-bronchodilator change in FEV1; and a partially reversible airflow limitation (partialRAL) group comprised 13 patients showing FEV1 reversibility (post-bronchodilator FEV1 increase ≥ 12%). The proportion of eosinophils in sputum was higher in the partialRAL group than in the nonRAL group (p < 0.01), and there was an inverse correlation between the proportion of eosinophils and FEV1 (p < 0.05). However, none of the patients had a history of asthma and skin prick test results did not differ between the two groups. In the patient sputum samples, neutrophils predominated. Serum levels of TNF, IL-6, IL-8, and RANTES (CCL5) were higher in patients than in controls (p < 0.001) but did not differ between the two patient groups. Conclusions: COPD patients with partial FEV1 reversibility appear to have higher sputum eosinophil counts and greater airway hyperresponsiveness than do those with no FEV1 reversibility. However, we found that COPD severity did not correlate with atopy or with the cytokine profile. PMID:27832230

  6. Inflammatory and immunological profiles in patients with COPD: relationship with FEV 1 reversibility

    Directory of Open Access Journals (Sweden)

    Cleriston Farias Queiroz

    Full Text Available ABSTRACT Objective: To determine whether COPD severity correlates with sputum cell counts, atopy, and asthma. Methods: This was a cross-sectional study involving 37 patients with COPD and 22 healthy subjects with normal lung function (controls. Sputum cell counts were determined by microscopy after centrifugation of samples. Skin prick tests were performed, and serum cytokines were determined by ELISA. Results: Patients were stratified by bronchodilator response: a non-reversible airflow limitation (nonRAL group comprised 24 patients showing no significant post-bronchodilator change in FEV1; and a partially reversible airflow limitation (partialRAL group comprised 13 patients showing FEV1 reversibility (post-bronchodilator FEV1 increase ≥ 12%. The proportion of eosinophils in sputum was higher in the partialRAL group than in the nonRAL group (p < 0.01, and there was an inverse correlation between the proportion of eosinophils and FEV1 (p < 0.05. However, none of the patients had a history of asthma and skin prick test results did not differ between the two groups. In the patient sputum samples, neutrophils predominated. Serum levels of TNF, IL-6, IL-8, and RANTES (CCL5 were higher in patients than in controls (p < 0.001 but did not differ between the two patient groups. Conclusions: COPD patients with partial FEV1 reversibility appear to have higher sputum eosinophil counts and greater airway hyperresponsiveness than do those with no FEV1 reversibility. However, we found that COPD severity did not correlate with atopy or with the cytokine profile.

  7. Experimental investigation into the interaction between the human body and room airflow and its effect on thermal comfort under stratum ventilation.

    Science.gov (United States)

    Cheng, Y; Lin, Z

    2016-04-01

    Room occupants' comfort and health are affected by the airflow. Nevertheless, they themselves also play an important role in indoor air distribution. This study investigated the interaction between the human body and room airflow under stratum ventilation. Simplified thermal manikin was employed to effectively resemble the human body as a flow obstacle and/or free convective heat source. Unheated and heated manikins were designed to fully evaluate the impact of the manikin at various airflow rates. Additionally, subjective human tests were conducted to evaluate thermal comfort for the occupants in two rows. The findings show that the manikin formed a local blockage effect, but the supply airflow could flow over it. With the body heat from the manikin, the air jet penetrated farther compared with that for the unheated manikin. The temperature downstream of the manikin was also higher because of the convective effect. Elevating the supply airflow rate from 7 to 15 air changes per hour varied the downstream airflow pattern dramatically, from an uprising flow induced by body heat to a jet-dominated flow. Subjective assessments indicated that stratum ventilation provided thermal comfort for the occupants in both rows. Therefore, stratum ventilation could be applied in rooms with occupants in multiple rows.

  8. Efficiency optimization in low inertia wells turbine-oscillating water column devices

    OpenAIRE

    2013-01-01

    The Wells turbine is a bidirectional air turbine which operates efficiently over a restricted range of air flow. The optimization of its efficiency requires control of rotational velocity in order to maintain the ratio between airflow and tip speed within the high efficiency range. This paper introduces two generator control strategies that optimize the power take-off efficiency for low inertia turbine systems in which instantaneous control of the turbine air flow to tip speed ratio is a real...

  9. A novel reversible carry-selected adder with low latency

    Science.gov (United States)

    Li, Ming-Cui; Zhou, Ri-Gui

    2016-07-01

    Reversible logic is getting more and more attention in quantum computing, optical computing, nanotechnology and low-power complementary metal oxide semiconductor designs since reversible circuits do not loose information during computation and have only small energy dissipation. In this paper, a novel carry-selected reversible adder is proposed primarily optimised for low latency. A 4-bit reversible full adder with two kinds of outputs, minimum delay and optimal quantum cost is presented as the building block for ?-bit reversible adder. Three new reversible gates NPG (new Peres gate), TEPG (triple extension of Peres gate) and RMUX21 (reversible 2-to-1 multiplexer) are proposed and utilised to design efficient adder units. The secondary carry propagation chain is carefully designed to reduce the time consumption. The novelty of the proposed design is the consideration of low latency. The comparative study shows that the proposed adder achieves the improvement from 61.46% to 95.29% in delay over the existing designs.

  10. An algebra of reversible computation

    OpenAIRE

    2016-01-01

    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.

  11. An Algebra of Reversible Computation

    OpenAIRE

    Yong WANG

    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. An algebra of reversible computation.

    Science.gov (United States)

    Wang, Yong

    2016-01-01

    We design an axiomatization for reversible computation called reversible ACP (RACP). It has four extendible modules: basic reversible processes algebra, algebra of reversible communicating processes, recursion and abstraction. Just like process algebra ACP in classical computing, RACP can be treated as an axiomatization foundation for reversible computation.

  13. A Novel Reversible BCD Adder For Nanotechnology Based Systems

    Directory of Open Access Journals (Sweden)

    Majid Haghparast

    2008-01-01

    Full Text Available This paper proposes two reversible logic gates, HNFG and HNG. The first gate HNFG can be used as two Feynman Gates. It is suitable for a single copy of two bits with no garbage outputs. It can be used as “Copying Circuit” to increase fan-out because fan-out is not allowed in reversible circuits. The second gate HNG can implement all Boolean functions. It also can be used to design optimized adder architectures. This paper also proposes a novel reversible full adder. One of the prominent functionalities of the proposed HNG gate is that it can work singly as a reversible full adder unit. The proposed reversible full adder contains only one gate. We show that its hardware complexity is less than the existing reversible full adders. The proposed full adder is then applied to the design of a reversible 4-bit parallel adder. A reversible Binary Coded Decimal (BCD adder circuit is also proposed. The proposed circuit can add two 4-bit binary variables and it transforms the result into the appropriate BCD number using efficient error correction modules. We show that the proposed reversible BCD adder has lower hardware complexity and it is much better and optimized in terms of number of reversible gates and garbage outputs with compared to the existing counterparts.

  14. Image Reversal Techniques With Standard Positive Photoresist

    Science.gov (United States)

    Long, Mary L.; Newman, Jeff

    1984-05-01

    The basic reaction of positive photoresist involves the conversion of the dissolution inhibitor (diazoketone) to a dissolution enhancer (carboxylic acid). The novolac-type resin is basically unchanged, but its solubility is controlled by the presence of either the dissolution inhibitor or enhancer. It has been demonstrated that the dissolution enhancer can be thermally degraded, and, under the proper conditions, this degradation can lead to the reversal of the resist image. It is, of course, imperative to optimize the developer selectivity and to capitalize on the specific characteristics of common positive resists to define a production-oriented image reversal process.**

  15. Single step purification of lactoperoxidase from whey involving reverse micelles-assisted extraction and its comparison with reverse micellar extraction.

    Science.gov (United States)

    Nandini, K E; Rastogi, Navin K

    2010-01-01

    The extraction of lactoperoxidase (EC 1.11.1.7) from whey was studied using single step reverse micelles-assisted extraction and compared with reverse micellar extraction. The reverse micelles-assisted extraction resulted in extraction of contaminating proteins and recovery of lactoperoxidase in the aqueous phase leading to its purification. Reverse micellar extraction at the optimized condition after forward and backward steps resulted in activity recovery of lactoperoxidase and purification factor of the order of 86.60% and 3.25-fold, respectively. Whereas reverse micelles-assisted extraction resulted in higher activity recovery of lactoperoxidase (127.35%) and purification factor (3.39-fold). The sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) profiles also evidenced that higher purification was obtained in reverse micelles-assisted extraction as compared of reverse micellar extracted lactoperoxidase.

  16. Reversible Data Hiding Techniques

    Directory of Open Access Journals (Sweden)

    Dhananjay Yadav

    2012-03-01

    Full Text Available Reversible data hiding is a technique that is used to hide data inside an image. The data is hidden in such a way that the exact or original data is not visible. The hidden data can be retrieved as and when required. There are several methods that are used in reversible data hiding techniques like Watermarking, Lossless embedding and encryption. In this paper we present a review of reversible watermarking techniques and show different methods that are used to get reversible data hiding technique with higher embedding capacity and invisible objects. Watermark need not be hidden. Watermarking can be applied to 1. Images, 2. Text, 3. Audio/video, 4. Software.

  17. 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....

  18. Adaptive Pairing Reversible Watermarking.

    Science.gov (United States)

    Dragoi, Ioan-Catalin; Coltuc, Dinu

    2016-05-01

    This letter revisits the pairwise reversible watermarking scheme of Ou et al., 2013. An adaptive pixel pairing that considers only pixels with similar prediction errors is introduced. This adaptive approach provides an increased number of pixel pairs where both pixels are embedded and decreases the number of shifted pixels. The adaptive pairwise reversible watermarking outperforms the state-of-the-art low embedding bit-rate schemes proposed so far.

  19. Reducing cholinergic constriction: the major reversible mechanism in COPD

    Directory of Open Access Journals (Sweden)

    V. Brusasco

    2006-12-01

    Full Text Available The airway narrowing in chronic obstructive pulmonary disease (COPD has often been misunderstood as being irreversible. However, a large proportion of patients with COPD do respond to bronchodilator agents with significant changes in lung function. Unlike in asthma, abnormalities in airway smooth muscle structure or function are not believed to play a key role in COPD airway narrowing. Although there are only limited data suggesting that cholinergic tone may be increased in COPD, the well-documented efficacy of antimuscarinic agents in increasing airway calibre suggests that cholinergic tone represents the major reversible component of airflow obstruction in these patients. Airway wall thickening and loss of airway-to-parenchyma interdependence are nonreversible components of airflow obstruction in COPD that may amplify the effect of changes in airway smooth muscle tone. Thus, keeping airway smooth muscle tone to a minimum might offer patients long-lasting airway patency and protection against breathlessness, which is the major complaint of patients with COPD. Receptor antagonism by anticholinergic agents can achieve effective relaxation of airway smooth muscle in COPD. According to a classical view of cholinergic receptor function and distribution, the ideal anticholinergic bronchodilator would be one that blocks both M1 and M3 receptors, which mediate airway smooth muscle contraction, but not the M2 receptor, stimulation of which reduces acetylcholine release from vagus nerve endings and prevents the airway smooth muscle from contracting by excessive increments. Agents with such pharmacodynamic selectivity are not available, but effective and prolonged inhibition of airway smooth muscle tone has been obtained with tiotropium, which binds to all three major muscarinic receptor subtypes, but for much longer to M3 than to M2 receptors. Recent data show that long-term treatment with tiotropium for 1 yr helps sustain 24-h airway patency. This

  20. NUMERICAL STUDIES ON AIRFLOW AND POLLUTANT DISPERSION IN URBAN STREET CANYONS FORMED BY SLANTED ROOF BUILDINGS

    Institute of Scientific and Technical Information of China (English)

    HUANG Yuan-dong; JIN Ming-xia; SUN Ya-nan

    2007-01-01

    Based on the CFD technique, fifteen cases were evaluated for the airflows and pollutant dispersions inside urban street canyons formed by slanted roof buildings. The simulated wind fields and concentration contours show that W/H, W/h and h/H (where W is the street width, and H and h are the heights of buildings at the leeward and windward sides of the street, respectively) are the crucial factors in determining the vortex structure and pollutant distribution within a canyon. It is concluded that (1) in a symmetrical canyon, at W/H =0.5 two vortices (an upper clockwise vortex between the slanted roofs and a lower counter-clockwise one) are developed and pollutants accumulate on the windward side of the street, whereas at W/H=2.0 only one clockwise vortex is generated and thus pollution piles up on the leeward side, (2) in a step-up canyon with W/H =0.5 to 2.0 (at h/H =1.5 to 2.0)and a step-down canyon with W/h=1.0 (at h/H =0.5 to 0.667), the pollution level close to the lower building is higher than that close to the taller building since a clockwise vortex is generated in the step-up canyon and a counter-clockwise one in the step-down canyon, (3) in a narrow step-down canyon with W/h=0.5 (at h/H =0.667) very poor ventilation properties is detected, and inside a wider step-down canyon with W/h=2.0 the vortex structure and consequently pollutant distribution varies greatly with h/H.

  1. Airflow and sediment movement within an inland blowout in Hulun Buir sandy grassland, Inner Mongolia, China

    Science.gov (United States)

    Sun, Yu; Hasi, Eerdun; Liu, Meiping; Du, Huishi; Guan, Chao; Tao, Binbin

    2016-09-01

    We measured wind flows and sediment transport rates through a blowout in Hulun Buir grassland, Inner Mongolia. Topography and the angle of incidence between the approaching wind and the blowout long-axis significantly affected the air flow. Flow separated and decelerated at the western wall and accelerated towards the east, until maximum wind speed occurred at the top of the depositional lobe, and then decelerated on the lee side. When airflow emerged on the eastern wall, resultant directions were always NW. When winds approached from directions within 17.5° of the blowout axis, both the northwestern and southwestern walls developed turbulent flow, and significant topographic steering occurred. The deceleration zone expanded eastwards from 10.3 to 12.8 m from the western rim. When the wind direction was more oblique than 17.5°, turbulent flow at the southwestern wall disappeared. 'S-shaped' flow intensified, causing more pronounced steering at the bottom, but topographic steering elsewhere was reduced, and the boundary of the deceleration moved to 10 m from the western rim. Minor sediment deposition occurred on the western wall, while other parts were eroded; maximum sediment transport occurred at the top of the depositional lobe. The approaching wind speed affected the sediment transport rate more than the direction; and spatial variability in sediment transport reflected differences in compaction, vegetation coverage, slope, aspect, and upwind sediment availability, resulting in asymmetrical development. Overall, flow-form interactions governed the flow structures and controlled the evolution of the blowout via sediment transport.

  2. Airflow Obstruction, Lung Function, and Incidence of Atrial Fibrillation: The Atherosclerosis Risk in Communities (ARIC) Study

    Science.gov (United States)

    Li, Jingjing; Agarwal, Sunil K.; Alonso, Alvaro; Blecker, Saul; Chamberlain, Alanna M.; London, Stephanie J.; Loehr, Laura R.; McNeill, Ann Marie; Poole, Charles; Soliman, Elsayed Z.; Heiss, Gerardo

    2014-01-01

    Background Reduced low forced expiratory volume in 1 second (FEV1) is reportedly associated with an increased risk of atrial fibrillation (AF). Extant reports do not provide separate estimates for never smokers, and for African Americans, who incongruously have lower AF incidence than Caucasians. Methods and Results We examined 15,004 middle-aged African Americans and Caucasians enrolled in ARIC cohort study. Standardized spirometry were collected at the baseline examination. Incident AF was identified from the first among the following: ICD codes for AF on hospital discharge records or death certificates or 12-lead ECGs performed during three triennial follow-up visits. Over an average follow-up of 17.5 years, a total of 1,691 (11%) participants developed new onset AF. The rate of incident AF was inversely associated with FEV1 in each of the four race and gender- groups. After multivariable adjustment for traditional cardiovascular disease risk factors and height, hazard ratios (95% confidence intervals) of AF comparing the lowest with the highest quartile of FEV1 were 1.37 (1.02,1.83) for white women, 1.49 (1.16,1.91) for white men, 1.63 (1.00,2.66) for black women, and 2.36 (1.30,4.29) for black men. The above associations were observed across all smoking status categories. Moderate/severe airflow obstruction (FEV1/FVC<0.70 and FEV1< 80% of predicted value) was also associated with higher AF incidence. Conclusions In this large population-based study with a long term follow-up, reduced FEV1 and obstructive respiratory disease were inversely - associated with a higher AF incidence after adjusting for measured confounders. PMID:24344084

  3. Tracheal sounds and airflow dynamics in surgically treated unilateral vocal fold paralysis.

    Science.gov (United States)

    Saarinen, A; Rihkanen, H; Malmberg, L P; Pekkanen, L; Sovijärvi, A R

    2001-03-01

    The aim of this study was to investigate the changes in tracheal sounds and airflow dynamics in patients who underwent surgical medialization of a unilaterally paralysed vocal fold. Ten adults with unilateral vocal fold paralysis but no history of pulmonary diseases were included. Vocal fold medialization was performed by an injection of autologous fascia into the paralysed vocal fold. Recording of tracheal sounds, flow-volume spirometry and body plethysmography were carried out before and 4-14 months after the operation. The mean number of inspiratory wheezes per respiratory cycle increased from 0.02 (range 0-0.10) to 0.42 (range 0-0.86) and the mean number of expiratory wheezes per respiratory cycle from 0.03 (range 0-0.20) to 0.36 (range 0-0.89). The increment was statistically significant (P=0.03 and P=0.04, respectively). The mean expiratory sound amplitude, in terms of root mean square (RMS), increased from 31.5 dB (range 24.0-38.0) to 34.9 dB (range 25-42) (P=0.03) and the average peak inspiratory flow (PIF) decreased from 4.63 l s-1 (range 2.84-7.51) to 4.03 l s-1 (range 2.27-6.68) (P=0.01). The results indicate that when the paralysed vocal fold is brought into midline by a surgical procedure, the prevalence of inspiratory and expiratory wheezes increases and sound intensity rises. According to this preliminary data tracheal sound analysis gives additional information for the assessment of the subtle changes in the larynx.

  4. Flight Test Results from the Rake Airflow Gage Experiment on the F-15B

    Science.gov (United States)

    Frederick, Michael; Ratnayake, Nalin

    2011-01-01

    The results are described of the Rake Airflow Gage Experiment (RAGE), which was designed and fabricated to support the flight test of a new supersonic inlet design using Dryden's Propulsion Flight Test Fixture (PFTF) and F-15B testbed airplane (see figure). The PFTF is a unique pylon that was developed for flight-testing propulsion-related experiments such as inlets, nozzles, and combustors over a range of subsonic and supersonic flight conditions. The objective of the RAGE program was to quantify the local flowfield at the aerodynamic interface plane of the Channeled Centerbody Inlet Experiment (CCIE). The CCIE is a fixed representation of a conceptual mixed-compression supersonic inlet with a translating biconic centerbody. The primary goal of RAGE was to identify the relationship between free-stream and local Mach number in the low supersonic regime, with emphasis on the identification of the particular free-stream Mach number that produced a local Mach number of 1.5. Measurements of the local flow angularity, total pressure distortion, and dynamic pressure over the interface plane were also desired. The experimental data for the RAGE program were obtained during two separate research flights. During both flights, local flowfield data were obtained during straight and level acceleration segments out to steady-state test points. The data obtained from the two flights showed small variations in Mach number, flow angularity, and dynamic pressure across the interface plane at all flight conditions. The data show that a free-stream Mach number of 1.65 will produce the desired local Mach number of 1.5 for CCIE. The local total pressure distortion over the interface plane at this condition was approximately 1.5%. At this condition, there was an average of nearly 2 of downwash over the interface plane. This small amount of downwash is not expected to adversely affect the performance of the CCIE inlet.

  5. Logical Design and Control of Network in Local Mine Air-Reversing System

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    This paper sets up a mathematical model of switching network and switching function by utilizing graphtheory to describe the logical function of different paths. The function varies with open and closed states of air doorsin a complex mine air sub-network, and the computer program for solving the switching function of complex net-works are offered. It gives the method for discriminating a reversible branch in a complex network by means of theswitching function, and the method of counter-inverted logical control of airflow inversion by means of open andshort circuit conversion of key branches. The research has solved the problem of the stablization of air flow for nor-mal ventination and reversing ventination in a diagonal network.

  6. FLOW CHARACTERISTICS OF WALL-FLOW DIESEL PARTICULATE FILTER SYSTEM WITH REVERSE PULSE AIR REGENERATION

    Institute of Scientific and Technical Information of China (English)

    Yao Chunde; Shao Yuping; Zhang Chunrun; Zi XinYun; Jiang Dahai; Deng Chenglin

    2005-01-01

    To simulate steady airflows inside of wall-flow diesel particulate filters (DPF) with different reverse blowing pipes collocation, a mathematical model of the flow in a DPF is established by an equivalent continuum approach. The experimental results agree well with the theoretical values calculated from the model. Simulation shows that the velocity and the pressure distribution of the filters in the regenerative process are key factors to the filter's regeneration. How to decrease the mal-distribution of the flow in the filter and how to achieve the better regenerative performance at the least cost of air consumption in the regenerative process are the ultimate goals of the study. Calculation and experiments show that the goals can be realized through adjusting the angle of two reverse blowing pipes and their relative location suitably.

  7. 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.

  8. Effective Outdoor Airflow and Its Characteristics in Building Room%建筑室内人员有效新风量及其特征性分析

    Institute of Scientific and Technical Information of China (English)

    王军; 张旭

    2011-01-01

    结合人体呼吸模型建立了室内人员所获得有效新风量的计算模型,并对不同通风模式、新风量大小和污染源强度影响下的有效新风量的特征性做出分析。研究结果表明,混合通风条件下的人员有效新风量要低于置换通风条件下的对应结果;同时,入室新风量的增大可以使人员有效新风量提高,但提高的程度取决于通风模式;此外,污染源强度的变化对人员有效新风量的影响较小。%Model for calculating person effective outdoor airflow in building room was obtained based on human breathe model.Characteristics of the person effective outdoor airflow were analyzed for different ventilation type,outdoor airflow of ventilation and pollution sources emission intensity.The results show that the person effective outdoor airflow of mixing ventilation is less than that of displacement ventilation.Furthermore,rise of outdoor airflow may make the person effective outdoor airflow increase,but its degree of increase depends on ventilation type.In addition,the pollution sources emission intensity has small influence on the person effective outdoor airflow.

  9. Reversible Communicating Processes

    Directory of Open Access Journals (Sweden)

    Geoffrey Brown

    2016-02-01

    Full Text Available Reversible distributed programs have the ability to abort unproductive computation paths and backtrack, while unwinding communication that occurred in the aborted paths. While it is natural to assume that reversibility implies full state recovery (as with traditional roll-back recovery protocols, an interesting alternative is to separate backtracking from local state recovery. For example, such a model could be used to create complex transactions out of nested compensable transactions where a programmer-supplied compensation defines the work required to "unwind" a transaction. Reversible distributed computing has received considerable theoretical attention, but little reduction to practice; the few published implementations of languages supporting reversibility depend upon a high degree of central control. The objective of this paper is to demonstrate that a practical reversible distributed language can be efficiently implemented in a fully distributed manner. We discuss such a language, supporting CSP-style synchronous communication, embedded in Scala. While this language provided the motivation for the work described in this paper, our focus is upon the distributed implementation. In particular, we demonstrate that a "high-level" semantic model can be implemented using a simple point-to-point protocol.

  10. 露天矿土-岩复合逆倾边坡空间形态优化%Space Shape Optimization of the Soil-rock Composite Reverse Dip Slope in Open-pit Mine

    Institute of Scientific and Technical Information of China (English)

    曹兰柱; 李广贺; 王东

    2016-01-01

    In view of the shape design of the boundary slope of the soil-rock composite reverse dip slope in the open-pit mine,the landslide model and stability of soil rock composite reverse dip slope in Dalianhe Open-pit Coal Mine is studied by a-dopting the method of rigid body limit equilibrium and three-dimensional numerical simulation. The study is based on the engi-neering practice of the compound reverse dip slope of the north slope of outer dump and the top slope of the stope in Dalianhe open-pit coal mine,by which the safety of the mining of coal resources of the north to boundary slope is guaranteed. The study results show that for the compound reverse dip slope of the north slope of outer dump and the top slope of the stope in Dalianhe open-pit coal mine,the landslide model is circular sliding;in order to meet the safety requirements, the mining slope angle should be up to 33°;the failure form of rock mass is the composition of tension and shear. At the foot of slope,local rock mass destruction should be done due to the stress concentration caused by the rock mass weight and it is the inducing factor of the whole slope failure.%针对露天矿土-岩复合逆倾边坡到界边坡形态设计问题,结合达连河露天煤矿外排土场北帮—采场顶帮复合逆倾边坡的工程实际,基于刚体极限平衡与三维数值模拟的手段,研究了露天矿土-岩复合逆倾边坡的滑坡模式及稳定性规律,设计了最终边坡形态,确保北帮到界过程中煤炭资源回采的安全。研究结果表明:达连河露天煤外排土场北帮—采场顶帮复合逆倾边坡的滑坡模式为圆弧滑动;使外排土场北帮—采场顶帮复合逆倾边坡满足安全要求的采场边坡角为33°;露天矿土-岩复合逆倾边坡岩体的破坏形式为拉张-剪切复合型,岩体自重作用下的坡脚处应力集中造成的局部岩体破坏是整体边坡失稳的诱发因素。

  11. The Association of Pipe and Cigar Use with Cotinine Levels, Lung Function and Airflow Obstruction: a Cross-sectional Study

    Science.gov (United States)

    Rodriguez, Josanna; Jiang, Rui; Johnson, W. Craig; MacKenzie, Barbara A; Smith, Lewis J.; Barr, R. Graham

    2010-01-01

    Background Cigarette smoking is the major cause of chronic obstructive pulmonary disease but studies on the contribution of other smoking techniques are sparse. Objective We hypothesized that pipe and cigar smoking was associated with elevated cotinine levels, decrements in lung function and increased odds of airflow obstruction. Design Cross-sectional study. Setting Population-based sample from six US communities. Participants The Multi-Ethnic Study of Atherosclerosis (MESA) recruited men and women ages 45-84 years without clinical cardiovascular disease. Measurements The MESA Lung Study measured spirometry following American Thoracic Society guidelines and urinary cotinine levels by immunoassay. Pipe-years and cigar-years were calculated as years from self-reported age of starting to quitting (or to current age among current users) × pipefuls or cigars per day. Results Of 3,528 participants, 8% reported pipe smoking (median 15 pipe-years), 11% reported cigar smoking (median 6 cigar-years), and 52% reported cigarette smoking (median 18 pack-years). Self-reported current pipe and cigar smokers had elevated urinary cotinine levels compared to never smokers. Pipe-years were associated with decrements in the forced expiratory volume in one second (FEV1) and cigar-years were associated with decrements in the FEV1 and the ratio of the FEV1 to the forced vital capacity. Participants who smoked pipes or cigars had an increased odds of airflow obstruction whether they had also smoked cigarettes (Odds ratio 3.43; 95% CI: 1.75, 6.71; PPipe and cigar smoking increased urinary cotinine levels and was associated with decrements in lung function and increased odds of airflow obstruction, even among participants who never smoked cigarettes. PMID:20157134

  12. High-resolution CT in patients with chronic airflow obstruction: correlation with clinical diagnosis and pulmonary function test

    Energy Technology Data Exchange (ETDEWEB)

    Hong, Ki Taek; Kang, Eun Young; Rhee, Ji Yong; Kim, Jin Hyung; Choi, Jung Ah; Cho, Jae Yoen; Oh, Yu Whan; Suh, Won Hyuck [College of Medicine, Korea University, Seoul (Korea, Republic of)

    2000-06-01

    To determine the utility of HRCT in the diagnosis of chronic airflow obstruction and to correlate the morphologic abnormalities revealed by this modality with functional impairment in patients with chronic airflow obstruction. This study involved 80 patients with chronic airflow obstruction who underwent HRCT and a pulmonary function test. Final clinical diagnosis in these patients was determined by a chest physician on the basis of clinical features, bronchoscopy, pulmonary function test, and HRCT. In order to diagnose and determine the extent of areas of decreased attenuation revealed by HRCT (the CT score), the findings of HRCT were retrospectively reviewed by two radiologists, who reached a consensus. Clinical and HRCT diagnoses were then compared, and the rate of agreement between them was calculated. The relationship between the extent of areas of decreased attenuation revealed by HRCT and by FEV1/FVC was evaluated using Correl's account and Student's unpaired t-test. The agreement rate between clinical and HRCT diagnoses was 77.5% (62/80). The rates for bronchiectasis (88.9%, 24/27), emphysema (93.9%, 31/33), and bronchiolitis obliterans (100%, 6/6) were considerably higher than those for chronic bronchitis and bronchial asthma. The correlation rate between CT score and FEV1/FVC was significant in bronchiectasis (p less than 0.05; r: -0.76) and bronchiolitis obliterans (p less than 0.01; r: -0.66), but not in cases involving emphysema, bronchial asthma, or chronic bronchitis (p greater than 0.05). HRCT is valuable in the diagnosis and prediction of physiologic impairment in patients with bronchiectasis and bronchiolitis obliterans, but has limited value in those with emphysema, chronic bronchitis or asthma. (author)

  13. Paired maximum inspiratory and expiratory plain chest radiographs for assessment of airflow limitation in chronic obstructive pulmonary disease

    Energy Technology Data Exchange (ETDEWEB)

    Kinoshita, Takashi, E-mail: tkino@med.kurume-u.ac.jp [Division of Respirology, Neurology, and Rheumatology, Department of Medicine, Kurume University School of Medicine, Kurume (Japan); Kawayama, Tomotaka, E-mail: kawayama_tomotaka@med.kurume-u.ac.jp [Division of Respirology, Neurology, and Rheumatology, Department of Medicine, Kurume University School of Medicine, Kurume (Japan); Imamura, Youhei, E-mail: mamura_youhei@med.kurume-u.ac.jp [Division of Respirology, Neurology, and Rheumatology, Department of Medicine, Kurume University School of Medicine, Kurume (Japan); Sakazaki, Yuki, E-mail: sakazaki@med.kurume-u.ac.jp [Division of Respirology, Neurology, and Rheumatology, Department of Medicine, Kurume University School of Medicine, Kurume (Japan); Hirai, Ryo, E-mail: hirai_ryou@kurume-u.ac.jp [Division of Respirology, Neurology, and Rheumatology, Department of Medicine, Kurume University School of Medicine, Kurume (Japan); Ishii, Hidenobu, E-mail: shii_hidenobu@med.kurume-u.ac.jp [Division of Respirology, Neurology, and Rheumatology, Department of Medicine, Kurume University School of Medicine, Kurume (Japan); Suetomo, Masashi, E-mail: jin_t_f_c@yahoo.co.jp [Division of Respirology, Neurology, and Rheumatology, Department of Medicine, Kurume University School of Medicine, Kurume (Japan); Matsunaga, Kazuko, E-mail: kmatsunaga@kouhoukai.or.jp [Division of Respirology, Neurology, and Rheumatology, Department of Medicine, Kurume University School of Medicine, Kurume (Japan); Azuma, Koichi, E-mail: azuma@med.kurume-u.ac.jp [Division of Respirology, Neurology, and Rheumatology, Department of Medicine, Kurume University School of Medicine, Kurume (Japan); Fujimoto, Kiminori, E-mail: kimichan@med.kurume-u.ac.jp [Department of Radiology, Kurume University School of Medicine, Kurume (Japan); Hoshino, Tomoaki, E-mail: hoshino@med.kurume-u.ac.jp [Division of Respirology, Neurology, and Rheumatology, Department of Medicine, Kurume University School of Medicine, Kurume (Japan)

    2015-04-15

    Highlights: •It is often to use computed tomography (CT) scan for diagnosis of chronic obstructive pulmonary disease. •CT scan is more expensive and higher. •A plane chest radiography more simple and cheap. Moreover, it is useful as detection of pulmonary emphysema, but not airflow limitation. •Our study demonstrated that the maximum inspiratory and expiratory plane chest radiography technique could detect severe airflow limitations. •We believe that the technique is helpful to diagnose the patients with chronic obstructive pulmonary disease. -- Abstract: Background: The usefulness of paired maximum inspiratory and expiratory (I/E) plain chest radiography (pCR) for diagnosis of chronic obstructive pulmonary disease (COPD) is still unclear. Objectives: We examined whether measurement of the I/E ratio using paired I/E pCR could be used for detection of airflow limitation in patients with COPD. Methods: Eighty patients with COPD (GOLD stage I = 23, stage II = 32, stage III = 15, stage IV = 10) and 34 control subjects were enrolled. The I/E ratios of frontal and lateral lung areas, and lung distance between the apex and base on pCR views were analyzed quantitatively. Pulmonary function parameters were measured at the same time. Results: The I/E ratios for the frontal lung area (1.25 ± 0.01), the lateral lung area (1.29 ± 0.01), and the lung distance (1.18 ± 0.01) were significantly (p < 0.05) reduced in COPD patients compared with controls (1.31 ± 0.02 and 1.38 ± 0.02, and 1.22 ± 0.01, respectively). The I/E ratios in frontal and lateral areas, and lung distance were significantly (p < 0.05) reduced in severe (GOLD stage III) and very severe (GOLD stage IV) COPD as compared to control subjects, although the I/E ratios did not differ significantly between severe and very severe COPD. Moreover, the I/E ratios were significantly correlated with pulmonary function parameters. Conclusions: Measurement of I/E ratios on paired I/E pCR is simple and

  14. Prevalence of undiagnosed airflow obstruction among people with a history of smoking in a primary care setting

    OpenAIRE

    2016-01-01

    Sau Nga Fu,1 Wai Cho Yu,2 Carlos King-Ho Wong,3 Margaret Choi-Hing Lam1 1Department of Family Medicine and Primary Health Care, Kowloon West Cluster, Hospital Authority, 2Department of Medicine and Geriatrics, Princess Margaret Hospital, 3Department of Family Medicine and Primary Care, Li Ka Shing Faculty of Medicine, University of Hong Kong, Hong Kong SAR Purpose: The purpose of this study was to define the prevalence of undiagnosed airflow obstruction (AO) among subjects with a history of...

  15. 雪铁龙C4 Cactus Airflow 2L概念车2L/100km

    Institute of Scientific and Technical Information of China (English)

    王晖

    2014-01-01

    面对城市拥挤、环保要求和经济压力,如今的消费者们将油耗作为购车时重要的考量指标。面对这个挑战,雪铁龙给出了令人震撼的答案—仅耗油2 L/100 km的雪铁龙全新C4 Cactus Airflow 2L概念车在2014巴黎车展上正式亮相。

  16. An approximate estimation of velocity profiles and turbulence factor models for air-flows along the exterior of TEFC induction motors

    Directory of Open Access Journals (Sweden)

    Klimenta Dardan O.

    2017-01-01

    Full Text Available Compared to a number of other existing correlations for heat transfer, the empirical correlations for forced convection from a short horizontal cylinder in axial air-flows usually do not involve the effects of changes in air-flow velocity and/or air-flow turbulence. Therefore, a common analysis of the heat transfer by using only one energy balance equation for entire outer surface of a solid is considered insufficient for induction motor applications because it fails to include aforementioned effects. This paper presents a novel, empirically-based methodology to estimate approximately the values of air-flow velocities and turbulence factors, that is, velocity profiles and turbulence factor models for stationary horizontal cylinders with and without fins (frame and two end-shields in axial air-flows. These velocity profiles and turbulence factor models can then be used in analytical modelling of steady-state heat transfer from the exterior of totally enclosed fan-cooled induction motors.

  17. Numerical simulation and disaster prevention for catastrophic fire airflow of main air-intake belt roadway in coal mine-A case study

    Institute of Scientific and Technical Information of China (English)

    周刚; 程卫民; 张睿; 沈宝堂; 聂文; 张磊; 王昊

    2015-01-01

    Coal mine belt fire develops very rapidly and is difficult to control. If not suppressed quickly, a belt fire could easily lead to airflow disorder and undermine the ventilation system. However, belt fire can be prevented effectively by establishing fire airflow control system. In this work, the 5th belt roadway of Kongzhuang coal mine was taken as the object of investigation, where geometrical models of this roadway were established firstly. Then, based on mathematical model of fire smoke flow, the CO volume fraction, smoke density distribution, air temperature and pollutant velocity vector in the roadway before and after taking airflow control measures were simulated by using Fluent software. It can be known from the simulation that with the normal ventilation status in 5th belt roadway, the countercurrent of smoke does not happen when a fire occurs; the roadway’s section is almost filled with CO at 10 m downstream from the fire source, and with air velocity getting stable gradually, the CO concentration reaches about 15 %. After taking airflow control measures, the effect range of temperature field which are harmful to the miners decreases from 69 m to 30 m; and the distance of the roadway fully filled with CO is 5 m farther than that before taking measures. Finally, according to the numerical simulation results and the actual condition of the belt roadway, the warning and automatic remote airflow control system with short-circuit method for the 5th belt roadway was designed to guarantee the safety production.

  18. Assessment of bronchodilator response through changes in lung volumes in chronic airflow obstruction

    Directory of Open Access Journals (Sweden)

    J.B. Figueroa-Casas

    2003-10-01

    Full Text Available Although FEV1 improvement is routinely used to define bronchodilator (BD response, it correlates poorly with clinical effects. Changes in lung volumes (LV have shown better correlation with exercise tolerance and might be more sensitive to detect BD effects. We assessed the additional contribution of measuring LV before and after BD to detect acute improvement in lung function not demonstrated by FEV1, and the influence of the response criteria selected on this contribution. We analyzed 98 spirometries and plethismographies performed pre and post BD in patients with airflow obstruction (FEV1/FVC 10% of baseline (D>5 anD>15% were also analyzed. FEV1 identified as responders 32% of patients. Greater proportions were uncovered by slow vital capacity (51%, p5 anD>15%. Mean change and proportions of responders for each LV varied significantly (pSi bien el aumento del VEF1 es habitualmente utilizado para definir respuesta a broncodilatadores (BD, su correlación con efectos clínicos es pobre. Los cambios en volúmenes pulmonares (VP han demostrado mejor correlación con tolerancia al ejercicio y podrían ser más sensibles para detectar efectos de los BD. Nosotros evaluamos la contribución adicional de medir VP antes y después de BD para detectar mejoría funcional aguda no demostrada por cambios del VEF1, y la influencia del criterio de respuesta seleccionado en esta contribución. Se analizaron 98 espirometrías y pletismografías realizadas pre y post BD en pacientes con obstrucción al flujo aéreo (VEF1/CVF 10% del basal (D>5 y 15% fueron también analizados. El VEF1 identificó como respondedores a 32% de los pacientes. Proporciones mayores fueron identificadas por capacidad vital lenta (51%, p5 y 15%. El cambio promedio y las proporciones de respondedores para cada VP variaron significativamente (p<0.05 según que el cambio fuese expresado como porcentaje del basal o del valor predicho. Una proporción considerable de pacientes con obstrucci

  19. Interleukin-6 and airflow limitation in chemical warfare patients with chronic obstructive pulmonary disease

    Directory of Open Access Journals (Sweden)

    Davood Attaran

    2010-09-01

    Full Text Available Davood Attaran1, Shahrzad M Lari1, Mohammad Towhidi1, Hassan Ghobadi Marallu2, Hossein Ayatollahi1, Mohammad Khajehdaluee1, Mostafa Ghanei3, Reza Basiri11Lung Disease and Tuberculosis Research Center, Mashhad University of Medical Science, 2Ardabil University of Medical Sciences, 3Research Center of Chemical Injuries, Baqiyatallah University of Medical Sciences, Tehran, IranObjectives: Chronic obstructive pulmonary disease (COPD is one of the main late complications of sulfur mustard poisoning. The aim of this study was to evaluate serum levels of interleukin (IL-6 in war veterans with pulmonary complications of sulfur mustard poisoning and their correlation with severity of airways disease.Methods: Fifty consecutive patients with sulfur mustard poisoning and stable COPD, and of mean age 46.3 ± 9.18 years were enrolled in this study. Thirty healthy men were selected as controls and matched to cases by age and body mass index. Spirometry, arterial blood gas, six-minute walk test, BODE (body mass index, obstruction, dyspnea, and exercise capacity, and St George’s Respiratory Questionnaire about quality of life were evaluated. Serum IL-6 was measured in both patient and control groups.Results: Fifty-four percent of patients had moderate COPD. Mean serum IL-6 levels were 15.01 ± standard deviation (SD 0.61 pg/dL and 4.59 ± 3.40 pg/dL in the case and control groups, respectively (P = 0.03. There was a significant correlation between IL-6 levels and Global Initiative for Chronic Obstructive Lung Disease stage (r = 0.25, P = 0.04 and between IL-6 and BODE index (r = 0.38, P = 0.01. There was also a significant negative correlation between serum IL-6 and forced expiratory volume in one second (FEV1, r = -0.36, P = 0.016.Conclusion: Our findings suggest that serum IL-6 is increased in patients with sulfur mustard poisoning and COPD, and may have a direct association with airflow limitation.Keywords: sulfur mustard, chronic obstructive pulmonary

  20. Simulation of turbulent airflow using a CT based upper airway model of a racehorse.

    Science.gov (United States)

    Rakesh, Vineet; Datta, Ashim K; Ducharme, Normand G; Pease, Anthony P

    2008-06-01

    Computational model for airflow through the upper airway of a horse was developed. Previous flow models for human airway do not hold true for horses due to significant differences in anatomy and the high Reynolds number of flow in the equine airway. Moreover, models that simulate the entire respiratory cycle and emphasize on pressures inside the airway in relation to various anatomical diseases are lacking. The geometry of the airway was created by reconstructing images obtained from computed tomography scans of a thoroughbred racehorse. Different geometries for inhalation and exhalation were used for the model based on the difference in the nasopharynx size during the two phases of respiration. The Reynolds averaged Navier-Stokes equations were solved for the isothermal flow with the standard k-epsilon model for turbulence. Transient pressure boundary conditions for the entire breathing cycle were obtained from past experimental studies on live horses. The flow equations were solved in a commercial finite volume solver. The flow rates, computed based on the applied pressure conditions, were compared to experimentally measured flow rates for model validation. Detailed analysis of velocity, pressure, and turbulence characteristics of the flow was done. Velocity magnitudes at various slices during inhalation were found to be higher than corresponding velocity magnitudes during exhalation. The front and middle parts of the nasopharynx were found to have minimum intraluminal pressure in the airway during inhalation. During exhalation, the pressures in the soft palate were higher compared to those in the larynx, epiglottis, and nasopharynx. Turbulent kinetic energy was found to be maximum at the entry to the airway and gradually decreased as the flow moved inside the airway. However, turbulent kinetic energy increased in regions of the airway with abrupt change in area. Based on the analysis of pressure distribution at different sections of the airway, it was concluded