WorldWideScience

Sample records for experimental characterization modeling

  1. Experimental Characterization and Modeling of PEM Fuel Cells

    DEFF Research Database (Denmark)

    Jespersen, Jesper Lebæk

    fundamental knowledge of the transport and electrochemical processes of PEM fuel cells and to provide methods for obtaining high quality data for PEM fuel cell simulation model validation. In this thesis three different areas of experimental characterization techniques was investigated, they include: Stack...... for obtaining very detailed data of the manifold flow. Moreover, the tools complement each other well, as high quality validation data can be obtained from PIV measurements to verify CFD models. AC Impedance Spectroscopy was used to thoroughly characterize a HTPEM single cell. The measurement method...... was furthermore transferred onto a Labview platform, which signiffcantly improves the exibility and lowers the cost of using this method. This technique is expected to bea very important future tool, used both for material characterization, celldiagnostic, system optimization and as a control input parameter...

  2. Experimental dynamic characterizations and modelling of disk vibrations for HDDs.

    Science.gov (United States)

    Pang, Chee Khiang; Ong, Eng Hong; Guo, Guoxiao; Qian, Hua

    2008-01-01

    Currently, the rotational speed of spindle motors in HDDs (Hard-Disk Drives) are increasing to improve high data throughput and decrease rotational latency for ultra-high data transfer rates. However, the disk platters are excited to vibrate at their natural frequencies due to higher air-flow excitation as well as eccentricities and imbalances in the disk-spindle assembly. These factors contribute directly to TMR (Track Mis-Registration) which limits achievable high recording density essential for future mobile HDDs. In this paper, the natural mode shapes of an annular disk mounted on a spindle motor used in current HDDs are characterized using FEM (Finite Element Methods) analysis and verified with SLDV (Scanning Laser Doppler Vibrometer) measurements. The identified vibration frequencies and amplitudes of the disk ODS (Operating Deflection Shapes) at corresponding disk mode shapes are modelled as repeatable disturbance components for servo compensation in HDDs. Our experimental results show that the SLDV measurements are accurate in capturing static disk mode shapes without the need for intricate air-flow aero-elastic models, and the proposed disk ODS vibration model correlates well with experimental measurements from a LDV.

  3. Peltier cells as temperature control elements: Experimental characterization and modeling

    International Nuclear Information System (INIS)

    Mannella, Gianluca A.; La Carrubba, Vincenzo; Brucato, Valerio

    2014-01-01

    The use of Peltier cells to realize compact and precise temperature controlled devices is under continuous extension in recent years. In order to support the design of temperature control systems, a simplified modeling of heat transfer dynamics for thermoelectric devices is presented. By following a macroscopic approach, the heat flux removed at the cold side of Peltier cell can be expressed as Q . c =γ(T c −T c eq ), where γ is a coefficient dependent on the electric current, T c and T c eq are the actual and steady state cold side temperature, respectively. On the other hand, a microscopic modeling approach was pursued via finite element analysis software packages. To validate the models, an experimental apparatus was designed and build-up, consisting in a sample vial with the surfaces in direct contact with Peltier cells. Both modeling approaches led to reliable prediction of transient and steady state sample temperature. -- Highlights: • Simplified modeling of heat transfer dynamics in Peltier cells. • Coupled macroscopic and microscopic approach. • Experimental apparatus: temperature control of a sample vial. • Both modeling approaches predict accurately the transient and steady state sample temperature

  4. Experimental characterization and modeling of an ethanol steam reformer

    DEFF Research Database (Denmark)

    Mandø, Matthias; Bovo, Mirko; Nielsen, Mads Pagh

    2006-01-01

    This work describes the characterization of an ethanol reforming system for a high temperature PEM fuel cell system. High temperature PEM fuel cells are well suited for operation on reformate gas due to the superior CO tolerance compared with low temperature PEM. Steam reforming of liquid biofuels...

  5. Computational modeling and experimental characterization of indoor aerosol transport

    International Nuclear Information System (INIS)

    Konecni, Snezana; Whicker, Jeffrey J.; Martin, Richard A.

    2002-01-01

    When a hazardous aerosol or gas is inadvertently or deliberately released in an occupied facility, the airborne material presents a hazard to people. Inadvertent accidents and exposures continue to occur in Los Alamos and other nuclear facilities despite state-of-art engineering and administrative controls, and heightened diligence. Despite the obvious need in occupational settings and for homeland defense, the body of research in hazardous aerosol dispersion and control in large, complex, ventilated enclosures is extremely limited. The science governing generation, transport, inhalation, and detection of airborne hazards is lacking and must be developed to where it can be used by engineers or safety professionals in the prediction of worker exposure, in the prevention of accidents, or in the mitigation of terrorist actions. In this study, a commercial computational fluid dynamics (CFD) code, CFX5.4, and experiments were used to assess flow field characteristics, and to investigate aerosol release and transport in a large, ventilated workroom in a facility at Savannah River Site. Steady state CFD results illustrating a complex, ventilation-induced, flow field with vortices, velocity gradients, and quiet zones are presented, as are time-dependent CFD and experimental aerosol dispersion results. The comparison of response times between CFD and experimental results was favorable. It is believed that future applications of CFD and experiments can have a favorable impact on the design of ventilation (HVAC) systems and worker safety with consideration to facility costs. Ultimately, statistical methods will be used in conjunction with CFD calculations to determine the optimal number and location of detectors, as well as optimal egress routes in event of a release.

  6. Photovoltaic Grid-Connected Modeling and Characterization Based on Experimental Results

    Science.gov (United States)

    Humada, Ali M.; Hojabri, Mojgan; Sulaiman, Mohd Herwan Bin; Hamada, Hussein M.; Ahmed, Mushtaq N.

    2016-01-01

    A grid-connected photovoltaic (PV) system operates under fluctuated weather condition has been modeled and characterized based on specific test bed. A mathematical model of a small-scale PV system has been developed mainly for residential usage, and the potential results have been simulated. The proposed PV model based on three PV parameters, which are the photocurrent, IL, the reverse diode saturation current, Io, the ideality factor of diode, n. Accuracy of the proposed model and its parameters evaluated based on different benchmarks. The results showed that the proposed model fitting the experimental results with high accuracy compare to the other models, as well as the I-V characteristic curve. The results of this study can be considered valuable in terms of the installation of a grid-connected PV system in fluctuated climatic conditions. PMID:27035575

  7. Photovoltaic Grid-Connected Modeling and Characterization Based on Experimental Results.

    Science.gov (United States)

    Humada, Ali M; Hojabri, Mojgan; Sulaiman, Mohd Herwan Bin; Hamada, Hussein M; Ahmed, Mushtaq N

    2016-01-01

    A grid-connected photovoltaic (PV) system operates under fluctuated weather condition has been modeled and characterized based on specific test bed. A mathematical model of a small-scale PV system has been developed mainly for residential usage, and the potential results have been simulated. The proposed PV model based on three PV parameters, which are the photocurrent, IL, the reverse diode saturation current, Io, the ideality factor of diode, n. Accuracy of the proposed model and its parameters evaluated based on different benchmarks. The results showed that the proposed model fitting the experimental results with high accuracy compare to the other models, as well as the I-V characteristic curve. The results of this study can be considered valuable in terms of the installation of a grid-connected PV system in fluctuated climatic conditions.

  8. Material characterization and non destructive testing by ultrasounds; modelling, simulation and experimental validation

    International Nuclear Information System (INIS)

    Noroy-Nadal, M.H.

    2002-06-01

    This memory presents the research concerning the characterization of materials and the Non Destructive Testing (N.D.T) by ultrasonics. The different topics include three steps: modeling, computations and experimental validation. The studied materials concern mainly metals. The memory is divided in four parts. The first one concerns the characterization of materials versus temperature. The determination of the shear modulus G(T) is especially studied for a large temperature range, and around the melting point. The second part is devoted to studies by photothermal devices essentially focused on the modeling of the mechanical displacement and the stress field in coated materials. In this particular field of interest, applications concern either the mechanical characterization of the coating, the defect detection in the structure and finally the evaluation of the coating adhesion. The third section is dedicated to microstructural characterization using acoustic microscopy. The evaluation of crystallographic texture is especially approached, for metallic objects obtained by forming. Before concluding and pointing out some perspectives to this work, the last section concerns the introduction of optimization techniques, applied to the material characterization by acoustic microscopy. (author)

  9. Experimental characterization and modelling of UO2 mechanical behaviour at high temperatures and high strain rates

    International Nuclear Information System (INIS)

    Salvo, Maxime

    2014-01-01

    The aim of this work is to characterize and model the mechanical behavior of uranium dioxide (UO 2 ) during a Reactivity Initiated Accident (RIA). The fuel loading during a RIA is characterized by high strain rates (up to 1/s) and high temperatures (1000 C - 2500 C). Two types of UO 2 pellets (commercial and high density) were therefore tested in compression with prescribed displacement rates (0.1 to 100 mm/min corresponding to strain rates of 10 -4 - 10 -1 /s) and temperatures (1100 C - 1350 C - 1550 C et 1700 C). Experimental results (geometry, yield stress and microstructure) allowed us to define a hyperbolic sine creep law and a Drucker-Prager criterion with associated plasticity, in order to model grain boundaries fragmentation at the macroscopic scale. Finite Element Simulations of these tests and of more than 200 creep tests were used to assess the model response to a wide range of temperatures (1100 C - 1700 C) and strain rates (10 -9 /s - 10 -1 /s). Finally, a constitutive law called L3F was developed for UO 2 by adding to the previous model irradiation creep and tensile macroscopic cracking. The L3F law was then introduced in the 1.5D scheme of the fuel performance code ALCYONE-RIA to simulate the REP-Na tests performed in the experimental reactor CABRI. Simulation results are in good agreement with post tests examinations. (author) [fr

  10. Modeling and Experimental Study on Characterization of Micromachined Thermal Gas Inertial Sensors

    Directory of Open Access Journals (Sweden)

    Yan Su

    2010-09-01

    Full Text Available Micromachined thermal gas inertial sensors based on heat convection are novel devices that compared with conventional micromachined inertial sensors offer the advantages of simple structures, easy fabrication, high shock resistance and good reliability by virtue of using a gaseous medium instead of a mechanical proof mass as key moving and sensing elements. This paper presents an analytical modeling for a micromachined thermal gas gyroscope integrated with signal conditioning. A simplified spring-damping model is utilized to characterize the behavior of the sensor. The model relies on the use of the fluid mechanics and heat transfer fundamentals and is validated using experimental data obtained from a test-device and simulation. Furthermore, the nonideal issues of the sensor are addressed from both the theoretical and experimental points of view. The nonlinear behavior demonstrated in experimental measurements is analyzed based on the model. It is concluded that the sources of nonlinearity are mainly attributable to the variable stiffness of the sensor system and the structural asymmetry due to nonideal fabrication.

  11. Experimental comparison of rate-dependent hysteresis models in characterizing and compensating hysteresis of piezoelectric tube actuators

    Energy Technology Data Exchange (ETDEWEB)

    Aljanaideh, Omar, E-mail: omaryanni@gmail.com [Department of Mechanical Engineering, The University of Jordan, Amman 11942 (Jordan); Habineza, Didace; Rakotondrabe, Micky [AS2M department, FEMTO-ST Institute, Univ. Bourgogne Franche-Comté, Univ. de Franche-Comté/CNRS/ENSMM, 25000 Besançon (France); Al Janaideh, Mohammad [Department of Mechanical and Industrial Engineering, The Mechatronics and Microsystems Design Laboratory, University of Toronto (Canada); Department of Mechatronics Engineering, The University of Jordan, Amman 11942 (Jordan)

    2016-04-01

    An experimental study has been carried out to characterize rate-dependent hysteresis of a piezoelectric tube actuator at different excitation frequencies. The experimental measurements were followed by modeling and compensation of the hysteresis nonlinearities of the piezoelectric tube actuator using both the inverse rate-dependent Prandtl–Ishlinskii model (RDPI) and inverse rate-independent Prandtl–Ishlinskii model (RIPI) coupled with a controller. The comparison of hysteresis modeling and compensation of the actuator with both models is presented.

  12. Experimental comparison of rate-dependent hysteresis models in characterizing and compensating hysteresis of piezoelectric tube actuators

    International Nuclear Information System (INIS)

    Aljanaideh, Omar; Habineza, Didace; Rakotondrabe, Micky; Al Janaideh, Mohammad

    2016-01-01

    An experimental study has been carried out to characterize rate-dependent hysteresis of a piezoelectric tube actuator at different excitation frequencies. The experimental measurements were followed by modeling and compensation of the hysteresis nonlinearities of the piezoelectric tube actuator using both the inverse rate-dependent Prandtl–Ishlinskii model (RDPI) and inverse rate-independent Prandtl–Ishlinskii model (RIPI) coupled with a controller. The comparison of hysteresis modeling and compensation of the actuator with both models is presented.

  13. Development and characterization of an experimental model of diet-induced metabolic syndrome in rabbit.

    Directory of Open Access Journals (Sweden)

    Oscar Julián Arias-Mutis

    Full Text Available Metabolic syndrome (MetS has become one of the main concerns for public health because of its link to cardiovascular disease. Murine models have been used to study the effect of MetS on the cardiovascular system, but they have limitations for studying cardiac electrophysiology. In contrast, the rabbit cardiac electrophysiology is similar to human, but a detailed characterization of the different components of MetS in this animal is still needed. Our objective was to develop and characterize a diet-induced experimental model of MetS that allows the study of cardiovascular remodeling and arrhythmogenesis. Male NZW rabbits were assigned to control (n = 15 or MetS group (n = 16, fed during 28 weeks with high-fat, high-sucrose diet. We measured weight, morphological characteristics, blood pressure, glycaemia, standard plasma biochemistry and the metabolomic profile at weeks 14 and 28. Liver histological changes were evaluated using hematoxylin-eosin staining. A mixed model ANOVA or unpaired t-test were used for statistical analysis (P<0.05. Weight, abdominal contour, body mass index, systolic, diastolic and mean arterial pressure increased in the MetS group at weeks 14 and 28. Glucose, triglycerides, LDL, GOT-AST, GOT/GPT, bilirubin and bile acid increased, whereas HDL decreased in the MetS group at weeks 14 and 28. We found a 40% increase in hepatocyte area and lipid vacuoles infiltration in the liver from MetS rabbits. Metabolomic analysis revealed differences in metabolites related to fatty acids, energetic metabolism and microbiota, compounds linked with cardiovascular disease. Administration of high-fat and high-sucrose diet during 28 weeks induced obesity, glucose intolerance, hypertension, non-alcoholic hepatic steatosis and metabolic alterations, thus reproducing the main clinical manifestations of the metabolic syndrome in humans. This experimental model should provide a valuable tool for studies into the mechanisms of cardiovascular

  14. A New Experimental Polytrauma Model in Rats: Molecular Characterization of the Early Inflammatory Response

    Directory of Open Access Journals (Sweden)

    Sebastian Weckbach

    2012-01-01

    Full Text Available Background. The molecular mechanisms of the immune response after polytrauma are highly complex and far from fully understood. In this paper, we characterize a new standardized polytrauma model in rats based on the early molecular inflammatory and apoptotic response. Methods. Male Wistar rats (250 g, 6–10/group were anesthetized and exposed to chest trauma (ChT, closed head injury (CHI, or Tib/Fib fracture including a soft tissue trauma (Fx + STT or to the following combination of injuries: (1 ChT; (2 ChT + Fx + STT; (3 ChT + CHI; (4 CHI; (5 polytrauma (PT = ChT + CHI + Fx + STT. Sham-operated rats served as negative controls. The inflammatory response was quantified at 2 hours and 4 hours after trauma by analysis of “key” inflammatory mediators, including selected cytokines and complement components, in serum and bronchoalveolar (BAL fluid samples. Results. Polytraumatized (PT rats showed a significant systemic and intrapulmonary release of cytokines, chemokines, and complement anaphylatoxins, compared to rats with isolated injuries or selected combinations of injuries. Conclusion. This new rat model appears to closely mimic the early immunological response of polytrauma observed in humans and may provide a valid basis for evaluation of the complex pathophysiology and future therapeutic immune modulatory approaches in experimental polytrauma.

  15. A New Experimental Polytrauma Model in Rats: Molecular Characterization of the Early Inflammatory Response

    Science.gov (United States)

    Weckbach, Sebastian; Perl, Mario; Heiland, Tim; Braumüller, Sonja; Stahel, Philip F.; Flierl, Michael A.; Ignatius, Anita; Gebhard, Florian; Huber-Lang, Markus

    2012-01-01

    Background. The molecular mechanisms of the immune response after polytrauma are highly complex and far from fully understood. In this paper, we characterize a new standardized polytrauma model in rats based on the early molecular inflammatory and apoptotic response. Methods. Male Wistar rats (250 g, 6–10/group) were anesthetized and exposed to chest trauma (ChT), closed head injury (CHI), or Tib/Fib fracture including a soft tissue trauma (Fx + STT) or to the following combination of injuries: (1) ChT; (2) ChT + Fx + STT; (3) ChT + CHI; (4) CHI; (5) polytrauma (PT = ChT + CHI + Fx + STT). Sham-operated rats served as negative controls. The inflammatory response was quantified at 2 hours and 4 hours after trauma by analysis of “key” inflammatory mediators, including selected cytokines and complement components, in serum and bronchoalveolar (BAL) fluid samples. Results. Polytraumatized (PT) rats showed a significant systemic and intrapulmonary release of cytokines, chemokines, and complement anaphylatoxins, compared to rats with isolated injuries or selected combinations of injuries. Conclusion. This new rat model appears to closely mimic the early immunological response of polytrauma observed in humans and may provide a valid basis for evaluation of the complex pathophysiology and future therapeutic immune modulatory approaches in experimental polytrauma. PMID:22481866

  16. Computational modeling and experimental characterization of bacterial microcolonies for rapid detection using light scattering

    Science.gov (United States)

    Bai, Nan

    A label-free and nondestructive optical elastic forward light scattering method has been extended for the analysis of microcolonies for food-borne bacteria detection and identification. To understand the forward light scattering phenomenon, a model based on the scalar diffraction theory has been employed: a bacterial colony is considered as a biological spatial light modulator with amplitude and phase modulation to the incoming light, which continues to propagate to the far-field to form a distinct scattering 'fingerprint'. Numerical implementation via angular spectrum method (ASM) and Fresnel approximation have been carried out through Fast Fourier Transform (FFT) to simulate this optical model. Sampling criteria to achieve unbiased and un-aliased simulation results have been derived and the effects of violating these conditions have been studied. Diffraction patterns predicted by these two methods (ASM and Fresnel) have been compared to show their applicability to different simulation settings. Through the simulation work, the correlation between the colony morphology and its forward scattering pattern has been established to link the number of diffraction rings and the half cone angle with the diameter and the central height of the Gaussian-shaped colonies. In order to experimentally prove the correlation, a colony morphology analyzer has been built and used to characterize the morphology of different bacteria genera and investigate their growth dynamics. The experimental measurements have demonstrated the possibility of differentiating bacteria Salmonella, Listeria, Escherichia in their early growth stage (100˜500 µm) based on their phenotypic characteristics. This conclusion has important implications in microcolony detection, as most bacteria of our interest need much less incubation time (8˜12 hours) to grow into this size range. The original forward light scatterometer has been updated to capture scattering patterns from microcolonies. Experiments have

  17. Experimental Characterization and Modeling of the Fracturing Behavior of Marcellus Shale

    Science.gov (United States)

    Jin, C.; Li, W.; Sageman, B. B.; Cusatis, G.

    2014-12-01

    Adequate knowledge and prediction of mechanical properties of shale are pivotal to the design of hydraulic fractures. The urgent technical challenge of such an endeavor is how to translate the highly heterogeneous nature of shale into a predictive model of the mechanical properties. Our group addressed this challenge by adopting a combined experimental and numerical approach to investigate fracture processes and failure mechanisms of shale.Lattice Discrete Particle Model (LDPM), having shown superior capabilities in predicting qualitative and quantitative behavior of concrete and concrete-like materials, as shown in Fig. 1, has been adopted to simulate mesoscale behavior of shale. The polyhedral cell system defining the geometric attributes of the rock microstructure is built via a 3D tessellation procedure based on X-ray microtomography results of microstructure and grain size distribution of shale specimens. The adopted tessellation procedure makes use of well-established packing algorithms for no-contact spherical particle placement and non-overlapping volume tessellation. The polyhedral particles interact through triangular facets where appropriate measure of stresses and strains are defined. Especially, LDPM is extended to simulate transversely isotropic materials by using orientation-dependent and strain-dependent strength limits coupled with orientation-dependent normal and shear stiffnesses on each facet. Appropriate interface constitutive equations are formulated to simulate all phenomena occurring at a scale that is smaller than the resolution of LDPM system, including microscopic fracture, frictional contact, particle breakage, pore collapse, and distributed damage. Bedding planes and natural joints are characterized by greatly decreased strength limits for facets within that region. To calibrate/validate the LDPM model, microscopic and mesoscopic experiments, including Brazilian tests, uniaxial compression tests, and three point-bending tests, are

  18. New modeling and experimental approaches for characterization of two-phase flow interfacial structure

    International Nuclear Information System (INIS)

    Ishii, Mamoru; Sun, Xiaodong

    2004-01-01

    This paper presents new experimental and modeling approaches in characterizing interfacial structures in gas-liquid two-phase flow. For the experiments, two objective approaches are developed to identify flow regimes and to obtain local interfacial structure data. First, a global measurement technique using a non-intrusive ring-type impedance void-meter and a self-organizing neural network is presented to identify the one-dimensional'' flow regimes. In the application of this measurement technique, two methods are discussed, namely, one based on the probability density function of the impedance probe measurement (PDF input method) and the other based on the sorted impedance signals, which is essentially the cumulative probability distribution function of the impedance signals (instantaneous direct signal input method). In the latter method, the identification can be made close to instantaneously since the required signals can be acquired over a very short time period. In addition, a double-sensor conductivity probe can also be used to obtain ''local'' flow regimes by using the instantaneous direct signal input method with the bubble chord length information. Furthermore, a newly designed conductivity probe with multiple double-sensor heads is proposed to obtain ''two-dimensional'' flow regimes across the flow channel. Secondly, a state-of-the-art four-sensor conductivity probe technique has been developed to obtain detailed local interfacial structure information. The four-sensor conductivity probe accommodates the double-sensor probe capability and can be applied in a wide range of flow regimes spanning from bubbly to churn-turbulent flows. The signal processing scheme is developed such that it categorizes the acquired parameters into two groups based on bubble cord length information. Furthermore, for the modeling of the interfacial structure characterization, the interfacial area transport equation proposed earlier has been studied to provide a dynamic and

  19. Polycystic ovarian syndrome: temporal characterization of the induction and reversion process in an experimental model

    OpenAIRE

    Salvetti, Natalia R.; Canal, Ana M.; Gimeno, Eduardo J.; Ortega, Hugo H.

    2004-01-01

    Numerous experimental models have been developed for the study of the polycystic ovarian syndrome in the rat. In the present study, the syndrome was induced by exposure to constant light. The process was evaluated during its induction and also during its reversion. The estral cycle was analyzed through the vaginal cytology; reproductive parameters were evaluated by mating, as well as the ovarian morphology. All the animals developed the syndrome after 13 weeks of permanent light. The histolog...

  20. Experimental characterization and modeling of commercial polybenzimidazole-based MEA performance

    DEFF Research Database (Denmark)

    Korsgaard, Anders; Refshauge, R. H.; Nielsen, Mads Pagh

    2006-01-01

    are currently published to enable good system design and modeling. In this paper the influence of operation on synthesis gas and the variation of the cathode stoichiometry are investigated based on a generic commercial membrane electrode assembly (MEA). The CO content in the anode gas was varied from 0 to 5......%, with CO2 contents ranging from 25 to 20% at temperatures ranging from 160 to 200 °C. The influence of the cathode stoichiometry was investigated in the interval of 2-5 at temperatures from 120 to 180 °C with pure hydrogen on the anode. A novel semi empirical model of the fuel cell voltage versus current...... density, cathode stoichiometry and temperature was derived. It shows excellent agreement with the experimental data. The simplicity and accuracy of the model makes it ideal for system modeling, control design and real-time applications....

  1. Characterization of vascular complications in experimental model of fructose-induced metabolic syndrome.

    Science.gov (United States)

    El-Bassossy, Hany M; Dsokey, Nora; Fahmy, Ahmed

    2014-12-01

    Vascular dysfunction is an important complication associated with metabolic syndrome (MS). Here we fully characterized vascular complications in a rat model of fructose-induced MS. MS was induced by adding fructose (10%) to drinking water to male Wistar rats of 6 weeks age. Blood pressure (BP) and isolated aorta responses phenylephrine (PE), KCl, acetylcholine (ACh), and sodium nitroprusside (SNP) were recorded after 6, 9, and 12 weeks of fructose administration. In addition, serum levels of glucose, insulin, uric acid, tumor necrosis factor α (TNFα), lipids, advanced glycation end products (AGEs), and arginase activity were determined. Furthermore, aortic reactive oxygen species (ROS) generation, hemeoxygenase-1 expression, and collagen deposition were examined. Fructose administration resulted in a significant hyperinslinemia after 6 weeks which continued for 12 weeks. It was also associated with a significant increase in BP after 6 weeks which was stable for 12 weeks. Aorta isolated from MS animals showed exaggerated contractility to PE and KCl and impaired relaxation to ACh compared with control after 6 weeks which were clearer at 12 weeks of fructose administration. In addition, MS animals showed significant increases in serum levels of lipids, uric acid, AGEs, TNFα, and arginase enzyme activity after 12 weeks of fructose administration. Furthermore, aortae isolated from MS animals were characterized by increased ROS generation and collagen deposition. In conclusion, adding fructose (10%) to drinking water produces a model of MS with vascular complications after 12 weeks that are characterized by insulin resistance, hypertension, disturbed vascular reactivity and structure, hyperuricemia, dyslipidemia, and low-grade inflammation.

  2. Experimental characterization and modelling of the alteration of fractured cement under CO2 storage conditions

    International Nuclear Information System (INIS)

    Abdoulghafour, Halidi

    2012-01-01

    The main purpose of this thesis was to characterize and to model the hydrodynamic and thermochemical processes leading to the alteration of the wellbore cement materials under borehole conditions. Percolation experiments were performed on fractured cement samples under CO 2 storage conditions (60 C and 10 MPa). Injection flow rate was dictated by the fracture aperture of each sample. CO 2 enriched brine was flowed along the fracture aperture, and permeability changes as well as chemical evolution of major cations were continuously acquired during the experiment time. Reaction paths developed by the alteration of the cement were characterized using microtomography and ESEM images. The experiments conducted using samples presenting large fracture apertures during 5 h showed that permeability was maintained constant during the experiment time. Three reacted layers were displaying by the alteration of portlandite and CSH. Long term experiment (26 h) conducted with large initial fracture aperture showed a decrease of the permeability after 15 hours of CO 2 exposure. Otherwise, experiments performed on samples presenting narrow apertures indicated the conversion of portlandite and CSH to calcite leading to the permeability reduction and the fracture clogging. Assemblages of phases and chemical changes were modelled using GEMS-PSI speciation code. We studied also using a coupled transport-reactive model the conditions leading to the cement alteration and the formation of associated layers. (author)

  3. Modeling and experimental characterization of a new piezoelectric sensor for low-amplitude vibration measurement

    International Nuclear Information System (INIS)

    Hou, X Y; Koh, C G; Kuang, K S C; Lee, W H

    2017-01-01

    This paper investigates the capability of a novel piezoelectric sensor for low-frequency and low-amplitude vibration measurement. The proposed design effectively amplifies the input acceleration via two amplifying mechanisms and thus eliminates the use of the external charge amplifier or conditioning amplifier typically employed for measurement system. The sensor is also self-powered, i.e. no external power unit is required. Consequently, wiring and electrical insulation for on-site measurement are considerably simpler. In addition, the design also greatly reduces the interference from rotational motion which often accompanies the translational acceleration to be measured. An analytical model is developed based on a set of piezoelectric constitutive equations and beam theory. Closed-form expression is derived to correlate sensor geometry and material properties with its dynamic performance. Experimental calibration is then carried out to validate the analytical model. After calibration, experiments are carried out to check the feasibility of the new sensor in structural vibration detection. From experimental results, it is concluded that the proposed sensor is suitable for measuring low-frequency and low-amplitude vibrations. (paper)

  4. Experimental characterization and physical modelling of the dose distribution of scanned proton pencil beams

    International Nuclear Information System (INIS)

    Pedroni, E; Scheib, S; Boehringer, T; Coray, A; Grossmann, M; Lin, S; Lomax, A

    2005-01-01

    In this paper we present the pencil beam dose model used for treatment planning at the PSI proton gantry, the only system presently applying proton therapy with a beam scanning technique. The scope of the paper is to give a general overview on the various components of the dose model, on the related measurements and on the practical parametrization of the results. The physical model estimates from first physical principles absolute dose normalized to the number of incident protons. The proton beam flux is measured in practice by plane-parallel ionization chambers (ICs) normalized to protons via Faraday-cup measurements. It is therefore possible to predict and deliver absolute dose directly from this model without other means. The dose predicted in this way agrees very well with the results obtained with ICs calibrated in a cobalt beam. Emphasis is given in this paper to the characterization of nuclear interaction effects, which play a significant role in the model and are the major source of uncertainty in the direct estimation of the absolute dose. Nuclear interactions attenuate the primary proton flux, they modify the shape of the depth-dose curve and produce a faint beam halo of secondary dose around the primary proton pencil beam in water. A very simple beam halo model has been developed and used at PSI to eliminate the systematic dependences of the dose observed as a function of the size of the target volume. We show typical results for the relative (using a CCD system) and absolute (using calibrated ICs) dosimetry, routinely applied for the verification of patient plans. With the dose model including the nuclear beam halo we can predict quite precisely the dose directly from treatment planning without renormalization measurements, independently of the dose, shape and size of the dose fields. This applies also to the complex non-homogeneous dose distributions required for the delivery of range-intensity-modulated proton therapy, a novel therapy technique

  5. A review of heat transfer in human tooth--experimental characterization and mathematical modeling.

    Science.gov (United States)

    Lin, Min; Xu, Feng; Lu, Tian Jian; Bai, Bo Feng

    2010-06-01

    With rapid advances in modern dentistry, high-energy output instruments (e.g., dental lasers and light polymerizing units) are increasingly employed in dental surgery for applications such as laser assisted tooth ablation, bleaching, hypersensitivity treatment and polymerization of dental restorative materials. Extreme high temperature occurs within the tooth during these treatments, which may induce tooth thermal pain (TTP) sensation. Despite the wide application of these dental treatments, the underlying mechanisms are far from clear. Therefore, there is an urgent need to better understand heat transfer (HT) process in tooth, thermally induced damage of tooth, and the corresponding TTP. This will enhance the design and optimization of clinical treatment strategies. This paper presents the state-of-the-art of the current understanding on HT in tooth, with both experimental study and mathematical modeling reviewed. Limitations of the current experimental and mathematical methodologies are discussed and potential solutions are suggested. Interpretation of TTP in terms of thermally stimulated dentinal fluid flow is also discussed. Copyright (c) 2010 Academy of Dental Materials. All rights reserved.

  6. Characterization of an experimental venous thrombus model with MRI, phlebography and histology

    International Nuclear Information System (INIS)

    Schmitz, S.A.; Schiffler, S.; Gust, R.; Winterhalter, S.; Wolf, K.J.; Coupland, S.E.

    2005-01-01

    Introduction: Several magnetic resonance (MR) techniques designed to demonstrate the characteristic signal intensity of blood degeneration products of thrombi have been suggested, but the effect of thrombus organization on the MR display, in particular with regard to its temporal evolution, remains to be determined. It is the purpose of this study to develop a stagnation thrombus model in rabbits and to characterize thrombus at different ages with two (MR) imaging techniques, phlebography and histology. Materials and Methods: Venous stagnation thrombi were induced in the external jugular veins of rabbits using a minimally invasive radiological technique to produce artificial embolic vascular occlusion and hypercoagulability. Twenty-five animals were divided into 5 groups of 5 animals, and each group underwent 1.5 T MR imaging at 1, 3, 5, 7 and 9 days after thrombus induction using a T1-weighted magnetization-prepared rapid gradient-echo sequence (MP-RAGE: TR 10.4 msec, TE 4.0 msec, FA 15 ) and a T2-weighted fast low-angle shot sequence (FLASH: TR 54 msec, TE 18 msec, FA15 ). The thrombus length was measured on the T1-weighted images. Thrombus conspicuity, signal intensity, and heterogeneity on T2* weighted images were described using visual scales. Radiographic venography and histology served as reference methods. Results: Thrombi were successfully induced in all animals. The overall thrombus length decreased from 43±9 (day 1 after induction) to 23±4 mm (day 9). On 3D-reconstructions of the T1-weighted images, the visible portion of the true thrombus length relative to the overall thrombus length was 0.16±0.3 (day 1), 0.24±0.3 (day 3),0.38±0.5 (day 5), 0.06±0.1 (day 7) and 0.00 (day 9). Sixteen of 25 thrombi were detectable with the T2*-weighted technique. The overall thrombus signal intensity decreased with the age of the thrombus from day 1 to day 9. The histological evaluation showed that the rabbit thrombi closely resemble human thrombi morphologically

  7. Plasma proteome and metabolome characterization of an experimental human thyrotoxicosis model

    DEFF Research Database (Denmark)

    Pietzner, Maik; Engelmann, Beatrice; Kacprowski, Tim

    2017-01-01

    BACKGROUND: Determinations of thyrotropin (TSH) and free thyroxine (FT4) represent the gold standard in evaluation of thyroid function. To screen for novel peripheral biomarkers of thyroid function and to characterize FT4-associated physiological signatures in human plasma we used an untargeted O...

  8. Drying of semicrystalline polymers: Mathematical modeling and experimental characterization of poly(vinyl alcohol) films

    OpenAIRE

    Wong, Sim-Siong; Altınkaya, Sacide; Mallapragada, Surya K.

    2004-01-01

    A mathematical model was developed to predict the drying mechanism of semicrystalline polymers involving multiple solvents. Since drying of semicrystalline polymers can be accompanied by changes in polymer degree of crystallinity, the model integrates crystallization kinetics and the Vrentas-Duda diffusion model to provide a better understanding of the mechanism. The model considers the effect of external conditions such as temperature, film shrinkage and diffusion and evaporation of multiple...

  9. Statistical Modelling and Characterization of Experimental mm-Wave Indoor Channels for Future 5G Wireless Communication Networks.

    Science.gov (United States)

    Al-Samman, A M; Rahman, T A; Azmi, M H; Hindia, M N; Khan, I; Hanafi, E

    This paper presents an experimental characterization of millimeter-wave (mm-wave) channels in the 6.5 GHz, 10.5 GHz, 15 GHz, 19 GHz, 28 GHz and 38 GHz frequency bands in an indoor corridor environment. More than 4,000 power delay profiles were measured across the bands using an omnidirectional transmitter antenna and a highly directional horn receiver antenna for both co- and cross-polarized antenna configurations. This paper develops a new path-loss model to account for the frequency attenuation with distance, which we term the frequency attenuation (FA) path-loss model and introduce a frequency-dependent attenuation factor. The large-scale path loss was characterized based on both new and well-known path-loss models. A general and less complex method is also proposed to estimate the cross-polarization discrimination (XPD) factor of close-in reference distance with the XPD (CIX) and ABG with the XPD (ABGX) path-loss models to avoid the computational complexity of minimum mean square error (MMSE) approach. Moreover, small-scale parameters such as root mean square (RMS) delay spread, mean excess (MN-EX) delay, dispersion factors and maximum excess (MAX-EX) delay parameters were used to characterize the multipath channel dispersion. Multiple statistical distributions for RMS delay spread were also investigated. The results show that our proposed models are simpler and more physically-based than other well-known models. The path-loss exponents for all studied models are smaller than that of the free-space model by values in the range of 0.1 to 1.4 for all measured frequencies. The RMS delay spread values varied between 0.2 ns and 13.8 ns, and the dispersion factor values were less than 1 for all measured frequencies. The exponential and Weibull probability distribution models best fit the RMS delay spread empirical distribution for all of the measured frequencies in all scenarios.

  10. Experimental characterization of airfoil boundary layers for improvement of aeroacoustic and aerodynamic modeling

    DEFF Research Database (Denmark)

    Fischer, Andreas

    2011-01-01

    for aerodynamic wind tunnels with a hard wall test section. Acoustic far field sound measurements are not possible in this tunnel due to the high background noise. The second wind tunnel is owned by Virginia Tech University. The test section has Kevlar walls which are acoustically transparent and it is surrounded...... sound measurements with a microphone array and measured surface pressure statistics as input up to a frequency of about 2000-3000Hz. The fluctuating surface pressure field can be measured in a wind tunnel with high background noise due to the high level of the fluctuating surface pressure field. Hence......The present work aims at the characterization of aerodynamic noise from wind turbines. There is a consensus among scientists that the dominant aerodynamic noise mechanism is turbulent boundary trailing edge noise. In almost all operational conditions the boundary layer flow over the wind turbine...

  11. Model analysis and experimental characterization of a microstrip vertex detector for a e+e- collider

    International Nuclear Information System (INIS)

    Walter, C.P.

    1989-09-01

    This thesis is constituted by several topics, apparently weakly correlated, but that are all addressed to improve the performances of the ALEPH microvertex detector both in the present version and in the upgraded one with JFET-CMOS electronics. A wide program of computer simulations about the upgraded JFET-CMOS version of the read-out electronics have been carried out to test its working principle and radiation hardness measurements have been performed on the prototypes of the same electronics to test its capability to stand the radiation environment foreseen in ALEPH. Extensive calculations of the capacitances in a microstrip detector are presented and their influence on the detector, both from the point of view of its noise performances and of the capacitive charge division method, has been analyzed theoretically, both through analytic calculations and numerical simulations; experimental measurements on the same relevant capacitances are discussed. Strictly connected to this point a computer code simulating the interaction of a minimum ionizing particle with the detector has been written and algorithms to determine the interaction point have been studied. This code has been later inserted in the Monte Carlo program of ALEPH. A point not strictly connected to ALEPH and still treated here is the analysis of the noise of two JFET devices, that is however interesting not as much for the results themselves, as for the analysis technique used that brought to identify noise sources that are usually difficult to detect and neglected. (orig.)

  12. Computational Modeling and Experimental Characterization of Martensitic Transformations in Nicoal for Self-Sensing Materials

    Science.gov (United States)

    Wallace, T. A.; Yamakov, V. I.; Hochhalter, J. D.; Leser, W. P.; Warner, J. E.; Newman, J. A.; Purja Pun, G. P.; Mishin, Y.

    2015-01-01

    Fundamental changes to aero-vehicle management require the utilization of automated health monitoring of vehicle structural components. A novel method is the use of self-sensing materials, which contain embedded sensory particles (SP). SPs are micron-sized pieces of shape-memory alloy that undergo transformation when the local strain reaches a prescribed threshold. The transformation is a result of a spontaneous rearrangement of the atoms in the crystal lattice under intensified stress near damaged locations, generating acoustic waves of a specific spectrum that can be detected by a suitably placed sensor. The sensitivity of the method depends on the strength of the emitted signal and its propagation through the material. To study the transition behavior of the sensory particle inside a metal matrix under load, a simulation approach based on a coupled atomistic-continuum model is used. The simulation results indicate a strong dependence of the particle's pseudoelastic response on its crystallographic orientation with respect to the loading direction and suggest possible ways of optimizing particle sensitivity. The technology of embedded sensory particles will serve as the key element in an autonomous structural health monitoring system that will constantly monitor for damage initiation in service, which will enable quick detection of unforeseen damage initiation in real-time and during onground inspections.

  13. Finite element modelling and experimental characterization of an electro-thermally actuated silicon-polymer micro gripper

    International Nuclear Information System (INIS)

    Krecinic, F; Duc, T Chu; Sarro, P M; Lau, G K

    2008-01-01

    This paper presents simulation and experimental characterization of an electro-thermally actuated micro gripper. This micro actuator can conceptually be seen as a bi-morph structure of SU-8 and silicon, actuated by thermal expansion of the polymer. The polymer micro gripper with an embedded comb-like silicon skeleton is designed to reduce unwanted out-of-plane bending of the actuator, while offering a large gripper stroke. The temperature and displacement field of the micro gripper structure is determined using a two-dimensional finite element analysis. This analysis is compared to experimental data from steady-state and transient measurements of the integrated heater resistance, which depends on the average temperature of the actuator. The stability of the polymer actuator is evaluated by recording the transient behaviour of the actual jaw displacements. The maximum single jaw displacement of this micro gripper design is 34 µm at a driving voltage of 4 V and an average actuator temperature of 170 °C. The transient thermal response is modelled by a first-order system with a characteristic time constant of 11.1 ms. The simulated force capability of the device is 0.57 mN per µm jaw displacement

  14. Corrosion chemistry closing comments: opportunities in corrosion science facilitated by operando experimental characterization combined with multi-scale computational modelling.

    Science.gov (United States)

    Scully, John R

    2015-01-01

    Recent advances in characterization tools, computational capabilities, and theories have created opportunities for advancement in understanding of solid-fluid interfaces at the nanoscale in corroding metallic systems. The Faraday Discussion on Corrosion Chemistry in 2015 highlighted some of the current needs, gaps and opportunities in corrosion science. Themes were organized into several hierarchical categories that provide an organizational framework for corrosion. Opportunities to develop fundamental physical and chemical data which will enable further progress in thermodynamic and kinetic modelling of corrosion were discussed. These will enable new and better understanding of unit processes that govern corrosion at the nanoscale. Additional topics discussed included scales, films and oxides, fluid-surface and molecular-surface interactions, selected topics in corrosion science and engineering as well as corrosion control. Corrosion science and engineering topics included complex alloy dissolution, local corrosion, and modelling of specific corrosion processes that are made up of collections of temporally and spatially varying unit processes such as oxidation, ion transport, and competitive adsorption. Corrosion control and mitigation topics covered some new insights on coatings and inhibitors. Further advances in operando or in situ experimental characterization strategies at the nanoscale combined with computational modelling will enhance progress in the field, especially if coupling across length and time scales can be achieved incorporating the various phenomena encountered in corrosion. Readers are encouraged to not only to use this ad hoc organizational scheme to guide their immersion into the current opportunities in corrosion chemistry, but also to find value in the information presented in their own ways.

  15. Experimental Object-Oriented Modelling

    DEFF Research Database (Denmark)

    Hansen, Klaus Marius

    through, e.g., technical prototyping and active user involvement. We introduce and examine “experimental object-oriented modelling” as the intersection of these practices. The contributions of this thesis are expected to be within three perspectives on models and modelling in experimental system...... development: Grounding We develop an empirically based conceptualization of modelling and use of models in system development projects characterized by a high degree of uncertainty in requirements and point to implications for tools and techniques for modelling in such a setting. Techniques We introduce......This thesis examines object-oriented modelling in experimental system development. Object-oriented modelling aims at representing concepts and phenomena of a problem domain in terms of classes and objects. Experimental system development seeks active experimentation in a system development project...

  16. P2X7 receptor-mediated calcium dynamics in HEK293 cells: experimental characterization and modelling approach

    International Nuclear Information System (INIS)

    Di Garbo, A; Alloisio, S; Nobile, M

    2012-01-01

    The P2X7 receptor (P2X7R) induces ionotropic Ca 2+  signalling in different cell types. It plays an important role in the immune response and in the nervous system. Here, the mechanisms underlying intracellular Ca 2+  variations evoked by 3′-O-(4-benzoyl)benzoyl-ATP (BzATP), a potent agonist of the P2X7R, in transfected HEK293 cells, are investigated both experimentally and theoretically. We propose a minimal model of P2X7R that is capable of reproducing, qualitatively and quantitatively, the experimental data. This approach was also adopted for the P2X7R variant, which lacks the entire C-terminus tail (trP2X7R). Then we introduce a biophysical model describing the Ca 2+  dynamics in HEK293. Our model gives an account of the ionotropic Ca 2+  influx evoked by BzATP on the basis of the kinetics model of P2X7R. To explain the complex Ca 2+  responses evoked by BzATP, the model predicted that an impairment in Ca 2+  extrusion flux through the plasma membrane is a key factor for Ca 2+ homeostasis in HEK293 cells. (paper)

  17. P2X7 receptor-mediated calcium dynamics in HEK293 cells: experimental characterization and modelling approach

    Science.gov (United States)

    Di Garbo, A.; Alloisio, S.; Nobile, M.

    2012-04-01

    The P2X7 receptor (P2X7R) induces ionotropic Ca2 + signalling in different cell types. It plays an important role in the immune response and in the nervous system. Here, the mechanisms underlying intracellular Ca2 + variations evoked by 3‧-O-(4-benzoyl)benzoyl-ATP (BzATP), a potent agonist of the P2X7R, in transfected HEK293 cells, are investigated both experimentally and theoretically. We propose a minimal model of P2X7R that is capable of reproducing, qualitatively and quantitatively, the experimental data. This approach was also adopted for the P2X7R variant, which lacks the entire C-terminus tail (trP2X7R). Then we introduce a biophysical model describing the Ca2 + dynamics in HEK293. Our model gives an account of the ionotropic Ca2 + influx evoked by BzATP on the basis of the kinetics model of P2X7R. To explain the complex Ca2 + responses evoked by BzATP, the model predicted that an impairment in Ca2 + extrusion flux through the plasma membrane is a key factor for Ca2 + homeostasis in HEK293 cells.

  18. Experimental determination of dosimetric characterization of a newly designed encapsulated interstitial brachytherapy source of 103Pd-model Pd-1

    International Nuclear Information System (INIS)

    Nath, Ravinder; Yue Ning; Roa, Eduardo

    2002-01-01

    A newly designed encapsulated 103 Pd source has been introduced (BrachySeed trade mark sign -Pd-103, also named Model Pd-1, manufactured by DRAXIMAGE Inc. and distributed by Cytogen Corp.) for interstitial brachytherapy to provide more isotropic dose distributions. In this work, the dosimetric characteristics of the 103 Pd source were measured with micro LiF TLD chips and dosimetry parameters were characterized based upon the American Association of Physicists in Medicine (AAPM) Task Group No. 43 formalism. The dose rate constant of the sources was determined to be 0.66±0.05 cGy h-1 U-1. The radial dose function was measured and was found to be similar to that of the Theragenics Model 200 103 Pd source. The anisotropy constant for the Model Pd-1 source was determined to be 1.03

  19. Material characterization and non destructive testing by ultrasounds; modelling, simulation and experimental validation; Caracterisation des materiaux et controle non destructif par ultrasons; modelisation, simulation et validation experimentale

    Energy Technology Data Exchange (ETDEWEB)

    Noroy-Nadal, M H

    2002-06-15

    This memory presents the research concerning the characterization of materials and the Non Destructive Testing (N.D.T) by ultrasonics. The different topics include three steps: modeling, computations and experimental validation. The studied materials concern mainly metals. The memory is divided in four parts. The first one concerns the characterization of materials versus temperature. The determination of the shear modulus G(T) is especially studied for a large temperature range, and around the melting point. The second part is devoted to studies by photothermal devices essentially focused on the modeling of the mechanical displacement and the stress field in coated materials. In this particular field of interest, applications concern either the mechanical characterization of the coating, the defect detection in the structure and finally the evaluation of the coating adhesion. The third section is dedicated to microstructural characterization using acoustic microscopy. The evaluation of crystallographic texture is especially approached, for metallic objects obtained by forming. Before concluding and pointing out some perspectives to this work, the last section concerns the introduction of optimization techniques, applied to the material characterization by acoustic microscopy. (author)

  20. Experimental characterization and modelling of non-linear coupling of the lower hybrid current drive power on Tore Supra

    Science.gov (United States)

    Preynas, M.; Goniche, M.; Hillairet, J.; Litaudon, X.; Ekedahl, A.; Colas, L.

    2013-01-01

    To achieve steady-state operation on future fusion devices, in particular on ITER, the coupling of the lower hybrid wave must be optimized on a wide range of edge conditions. However, under some specific conditions, deleterious effects on the lower hybrid current drive (LHCD) coupling are sometimes observed on Tore Supra. In this way, dedicated LHCD experiments have been performed using the LHCD system of Tore Supra, composed of two different conceptual designs of launcher: the fully active multi-junction (FAM) and the new passive active multi-junction (PAM) antennas. A non-linear interaction between the electron density and the electric field has been characterized in a thin plasma layer in front of the two LHCD antennas. The resulting dependence of the power reflection coefficient (RC) with the LHCD power is not predicted by the standard linear theory of the LH wave coupling. A theoretical model is suggested to describe the non-linear wave-plasma interaction induced by the ponderomotive effect and implemented in a new full wave LHCD code, PICCOLO-2D (ponderomotive effect in a coupling code of lower hybrid wave-2D). The code self-consistently treats the wave propagation in the antenna vicinity and its interaction with the local edge plasma density. The simulation reproduces very well the occurrence of a non-linear behaviour in the coupling observed in the LHCD experiments. The important differences and trends between the FAM and the PAM antennas, especially a larger increase in RC for the FAM, are also reproduced by the PICCOLO-2D simulation. The working hypothesis of the contribution of the ponderomotive effect in the non-linear observations of LHCD coupling is therefore validated through this comprehensive modelling for the first time on the FAM and PAM antennas on Tore Supra.

  1. Experimental characterization and modelling of non-linear coupling of the lower hybrid current drive power on Tore Supra

    International Nuclear Information System (INIS)

    Preynas, M.; Goniche, M.; Hillairet, J.; Litaudon, X.; Ekedahl, A.; Colas, L.

    2013-01-01

    To achieve steady-state operation on future fusion devices, in particular on ITER, the coupling of the lower hybrid wave must be optimized on a wide range of edge conditions. However, under some specific conditions, deleterious effects on the lower hybrid current drive (LHCD) coupling are sometimes observed on Tore Supra. In this way, dedicated LHCD experiments have been performed using the LHCD system of Tore Supra, composed of two different conceptual designs of launcher: the fully active multi-junction (FAM) and the new passive active multi-junction (PAM) antennas. A non-linear interaction between the electron density and the electric field has been characterized in a thin plasma layer in front of the two LHCD antennas. The resulting dependence of the power reflection coefficient (RC) with the LHCD power is not predicted by the standard linear theory of the LH wave coupling. A theoretical model is suggested to describe the non-linear wave–plasma interaction induced by the ponderomotive effect and implemented in a new full wave LHCD code, PICCOLO-2D (ponderomotive effect in a coupling code of lower hybrid wave-2D). The code self-consistently treats the wave propagation in the antenna vicinity and its interaction with the local edge plasma density. The simulation reproduces very well the occurrence of a non-linear behaviour in the coupling observed in the LHCD experiments. The important differences and trends between the FAM and the PAM antennas, especially a larger increase in RC for the FAM, are also reproduced by the PICCOLO-2D simulation. The working hypothesis of the contribution of the ponderomotive effect in the non-linear observations of LHCD coupling is therefore validated through this comprehensive modelling for the first time on the FAM and PAM antennas on Tore Supra. (paper)

  2. Experimental Characterization and Modelization of Ion Exchange Kinetics for a Carboxylic Resin in Infinite Solution Volume Conditions. Application to Monovalent-Trivalent Cations Exchange

    Energy Technology Data Exchange (ETDEWEB)

    Picart, S.; Mokhtari, H.; Jobelin, I. [CEA Marcoule, Nucl Energy Div, RadioChem and Proc Dept, Actinides Chem and Convers Lab, F-30207 Bagnols Sur Ceze (France); Ramiere, I. [Fuel Simulat Lab, Fuel Study Dept, F-13108 St Paul Les Durance (France)

    2010-07-01

    This study is devoted to the characterization of ion exchange inside a microsphere of carboxylic resin. It aims at describing the kinetics of this exchange reaction which is known to be controlled by interdiffusion in the particle. The fractional attainment of equilibrium function of time depends on the concentration of the cations in the resin which can be modelled by the Nernst-Planck equation. A powerful approach for the numerical resolution of this equation is introduced in this paper. This modeling is based on the work of Helfferich but involves an implicit numerical scheme which reduces the computational cost. Knowing the diffusion coefficients of the cations in the resin and the radius of the spherical exchanger, the kinetics can be hence completely determined. When those diffusion parameters are missing, they can be deduced by fitting experimental data of fractional attainment of equilibrium. An efficient optimization tool coupled with the implicit resolution has been developed for this purpose. A monovalent/trivalent cation exchange had been experimentally characterized for a carboxylic resin. Diffusion coefficients and concentration profiles in the resin were then deduced through this new model. (authors)

  3. Experimental Characterization and Modelization of Ion Exchange Kinetics for a Carboxylic Resin in Infinite Solution Volume Conditions. Application to Monovalent-Trivalent Cations Exchange

    International Nuclear Information System (INIS)

    Picart, S.; Mokhtari, H.; Jobelin, I.; Ramiere, I.

    2010-01-01

    This study is devoted to the characterization of ion exchange inside a microsphere of carboxylic resin. It aims at describing the kinetics of this exchange reaction which is known to be controlled by interdiffusion in the particle. The fractional attainment of equilibrium function of time depends on the concentration of the cations in the resin which can be modelled by the Nernst-Planck equation. A powerful approach for the numerical resolution of this equation is introduced in this paper. This modeling is based on the work of Helfferich but involves an implicit numerical scheme which reduces the computational cost. Knowing the diffusion coefficients of the cations in the resin and the radius of the spherical exchanger, the kinetics can be hence completely determined. When those diffusion parameters are missing, they can be deduced by fitting experimental data of fractional attainment of equilibrium. An efficient optimization tool coupled with the implicit resolution has been developed for this purpose. A monovalent/trivalent cation exchange had been experimentally characterized for a carboxylic resin. Diffusion coefficients and concentration profiles in the resin were then deduced through this new model. (authors)

  4. Characterization of experimental cements with endodontic goal

    International Nuclear Information System (INIS)

    Dantas, A.M.X.; Sousa, W.J.B.; Oliveira, E.D.C.; Carrodeguas, R.G.; Fook, M.V. Lia; Universidade Estadual da Paraiba

    2017-01-01

    The present study aimed to characterize experimental endodontic cements using as comparative parameter MTA cement. Two experimental endodontic cements were assessed: one based on 95% tri-strontium aluminate and 5% gypsum (CE1) and another based on 50% Sr_3Al_2O_6 and 50% non-structural white cement (CE2). Experimental cements were manipulated and characterized by scanning electron microscopy (SEM), coupled to EDS mode, X-ray diffractometer (XRD) and Thermogravimetric (TG) analysis. Data analysis demonstrated that the particles of the materials used presented varied shapes and sizes, with similar elements and crystalline behavior. However, CE1 presented increased mass loss. Experimental cements presents similarities to MTA, nevertheless, further studies are encourage to determinate comparative properties with the commercially material. (author)

  5. Experimental Characterization and Modeling of Thermal Contact Resistance of Electric Machine Stator-to-Cooling Jacket Interface Under Interference Fit Loading

    Energy Technology Data Exchange (ETDEWEB)

    Cousineau, Justine E [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Bennion, Kevin S [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Chieduko, Victor [UQM Technologies, Inc.; Lall, Rajiv [UQM Technologies, Inc.; Gilbert, Alan [UQM Technologies, Inc.

    2018-05-08

    Cooling of electric machines is a key to increasing power density and improving reliability. This paper focuses on the design of a machine using a cooling jacket wrapped around the stator. The thermal contact resistance (TCR) between the electric machine stator and cooling jacket is a significant factor in overall performance and is not well characterized. This interface is typically an interference fit subject to compressive pressure exceeding 5 MPa. An experimental investigation of this interface was carried out using a thermal transmittance setup using pressures between 5 and 10 MPa. The results were compared to currently available models for contact resistance, and one model was adapted for prediction of TCR in future motor designs.

  6. Solid phase characterization and gas transfers through unsaturated porous media: experimental study and modeling applied diffusion of hydrogen through cement-based materials

    International Nuclear Information System (INIS)

    Vu, T.H.

    2009-10-01

    This thesis documents the relationship between the porous microstructure of cement based materials and theirs gaseous diffusivity properties relative to the aqueous phase location and the global saturation level of the material. The materials studied are cement pastes and mortars. To meet the thesis objective, the materials are characterized in detail by means of several experimental methods: mercury intrusion porosimetry, water porosimetry, thermo-poro-metry, nitrogen sorption and water desorption. In addition, diffusion tests realized on materials maintained in controlled humidity chambers allow obtaining the effective hydrogen diffusivity as function of the microstructure and the saturation state of material with a gas chromatography. The experimental results are then used as a data base that is compared to a modeling approach. The model developed consists of a combination of ordinary diffusion (Fick regime) and Knudsen diffusion of hydrogen. The model also accounts for the effects of the liquid curtains, the impact of tortuosity on gas diffusion, and the saturation level of the porous system. (author)

  7. Experimental characterization of post rigor mortis human muscle subjected to small tensile strains and application of a simple hyper-viscoelastic model.

    Science.gov (United States)

    Gras, Laure-Lise; Laporte, Sébastien; Viot, Philippe; Mitton, David

    2014-10-01

    In models developed for impact biomechanics, muscles are usually represented with one-dimensional elements having active and passive properties. The passive properties of muscles are most often obtained from experiments performed on animal muscles, because limited data on human muscle are available. The aim of this study is thus to characterize the passive response of a human muscle in tension. Tensile tests at different strain rates (0.0045, 0.045, and 0.45 s⁻¹) were performed on 10 extensor carpi ulnaris muscles. A model composed of a nonlinear element defined with an exponential law in parallel with one or two Maxwell elements and considering basic geometrical features was proposed. The experimental results were used to identify the parameters of the model. The results for the first- and second-order model were similar. For the first-order model, the mean parameters of the exponential law are as follows: Young's modulus E (6.8 MPa) and curvature parameter α (31.6). The Maxwell element mean values are as follows: viscosity parameter η (1.2 MPa s) and relaxation time τ (0.25 s). Our results provide new data on a human muscle tested in vitro and a simple model with basic geometrical features that represent its behavior in tension under three different strain rates. This approach could be used to assess the behavior of other human muscles. © IMechE 2014.

  8. Pretest characterization of WIPP experimental waste

    International Nuclear Information System (INIS)

    Johnson, J.; Davis, H.

    1991-01-01

    The Waste Isolation Pilot Plant (WIPP) near Carlsbad, New Mexico, is an underground repository designed for the storage and disposal of transuranic (TRU) wastes from US Department of Energy (DOE) facilities across the country. The Performance Assessment (PA) studies for WIPP address compliance of the repository with applicable regulations, and include full-scale experiments to be performed at the WIPP site. These experiments are the bin-scale and alcove tests to be conducted by Sandia National Laboratories (SNL). Prior to conducting these experiments, the waste to be used in these tests needs to be characterized to provide data on the initial conditions for these experiments. This characterization is referred to as the Pretest Characterization of WIPP Experimental Waste, and is also expected to provide input to other programmatic efforts related to waste characterization. The purpose of this paper is to describe the pretest waste characterization activities currently in progress for the WIPP bin-scale waste, and to discuss the program plan and specific analytical protocols being developed for this characterization. The relationship between different programs and documents related to waste characterization efforts is also highlighted in this paper

  9. Characterization of melting and solidification in a real scale PCM-air heat exchanger: Numerical model and experimental validation

    International Nuclear Information System (INIS)

    Dolado, Pablo; Lazaro, Ana; Marin, Jose M.; Zalba, Belen

    2011-01-01

    Research highlights: → A mathematical model of a PCM-air heat exchanger is developed and validated. → Validation range is 0.7-2.1 m/s for airflow and 8-45 o C for air inlet temperature. → Better λPCM lead to minor improvement as the main resistance is mostly on air side. → 1 o C mismatch in the PCM h-T curve could lead to errors of up to 20% in power. → The accuracy of material properties' data used as inputs in the model is stressed. -- Abstract: This paper describes the models developed to simulate the performance of a thermal energy storage (TES) unit in a real scale PCM-air heat exchanger, analyzing the heat transfer between the air and a commercially available and slab macroencapsulated phase change material (PCM). The models are based on one-dimensional conduction analysis, utilizing finite differences method, and implicit formulation, using the thermo-physical data of the PCM measured in the laboratory: enthalpy and thermal conductivity as functions of temperature. The models can take into account the hysteresis of the enthalpy curve and the convection inside the PCM, using effective conductivity when necessary. Two main paths are followed to accomplish the modeling: the thermal analysis of a single plate, and the thermal behavior of the entire TES unit. Comparisons between measurements and simulations are undertaken to evaluate the models. Average errors of less than 12% on thermal power are obtained for the entire cycle. Once the model is validated, a series of parameters and variables is studied to verify their influence on the behavior and design of the TES unit.

  10. Experimental characterization of the perceptron laser rangefinder

    Science.gov (United States)

    Kweon, I. S.; Hoffman, Regis; Krotkov, Eric

    1991-01-01

    In this report, we characterize experimentally a scanning laser rangefinder that employs active sensing to acquire three-dimensional images. We present experimental techniques applicable to a wide variety of laser scanners, and document the results of applying them to a device manufactured by Perceptron. Nominally, the sensor acquires data over a 60 deg x 60 deg field of view in 256 x 256 pixel images at 2 Hz. It digitizes both range and reflectance pixels to 12 bits, providing a maximum range of 40 m and a depth resolution of 1 cm. We present methods and results from experiments to measure geometric parameters including the field of view, angular scanning increments, and minimum sensing distance. We characterize qualitatively problems caused by implementation flaws, including internal reflections and range drift over time, and problems caused by inherent limitations of the rangefinding technology, including sensitivity to ambient light and surface material. We characterize statistically the precision and accuracy of the range measurements. We conclude that the performance of the Perceptron scanner does not compare favorably with the nominal performance, that scanner modifications are required, and that further experimentation must be conducted.

  11. Experimental measurements and theoretical model of the cryogenic performance of bialkali photocathode and characterization with Monte Carlo simulation

    Directory of Open Access Journals (Sweden)

    Huamu Xie

    2016-10-01

    Full Text Available High-average-current, high-brightness electron sources have important applications, such as in high-repetition-rate free-electron lasers, or in the electron cooling of hadrons. Bialkali photocathodes are promising high-quantum-efficiency (QE cathode materials, while superconducting rf (SRF electron guns offer continuous-mode operation at high acceleration, as is needed for high-brightness electron sources. Thus, we must have a comprehensive understanding of the performance of bialkali photocathode at cryogenic temperatures when they are to be used in SRF guns. To remove the heat produced by the radio-frequency field in these guns, the cathode should be cooled to cryogenic temperatures. We recorded an 80% reduction of the QE upon cooling the K_{2}CsSb cathode from room temperature down to the temperature of liquid nitrogen in Brookhaven National Laboratory (BNL’s 704 MHz SRF gun. We conducted several experiments to identify the underlying mechanism in this reduction. The change in the spectral response of the bialkali photocathode, when cooled from room temperature (300 K to 166 K, suggests that a change in the ionization energy (defined as the energy gap from the top of the valence band to vacuum level is the main reason for this reduction. We developed an analytical model of the process, based on Spicer’s three-step model. The change in ionization energy, with falling temperature, gives a simplified description of the QE’s temperature dependence. We also developed a 2D Monte Carlo code to simulate photoemission that accounts for the wavelength-dependent photon absorption in the first step, the scattering and diffusion in the second step, and the momentum conservation in the emission step. From this simulation, we established a correlation between ionization energy and reduction in the QE. The simulation yielded results comparable to those from the analytical model. The simulation offers us additional capabilities such as calculation

  12. Experimental Viscoelastic Characterization of Corn Cob Composited ...

    African Journals Online (AJOL)

    The nature of viscoelasticity in biomateria1s and the techniques for characterizing their rheological properties were reviewed. Relaxation tests were performed with cylindrical samples of corn cob composites which were initially subjected to radial compression. It was found that a Maxwell model composed of two simple ...

  13. Chemical characterization of a red raspberry fruit extract and evaluation of its pharmacological effects in experimental models of acute inflammation and collagen-induced arthritis.

    Science.gov (United States)

    Figueira, M E; Câmara, M B; Direito, R; Rocha, J; Serra, A T; Duarte, C M M; Fernandes, A; Freitas, M; Fernandes, E; Marques, M C; Bronze, M R; Sepodes, B

    2014-12-01

    Berries are an important dietary source of fibres, vitamins, minerals and some biologically active non-nutrients. A red raspberry fruit extract was characterized in terms of phenolic content and the anti-inflammatory properties and protective effects were evaluated in two experimental models of inflammation. The antioxidant potential of the extract, the cellular antioxidant activity and the effects over neutrophils' oxidative burst were also studied to provide a mechanistic insight for the anti-inflammatory effects observed. The extract was administered in a dose of 15 mg kg(-1), i.p. and significantly inhibited paw oedema formation in the rat. The same dose was administered via i.p. and p.o. routes in the collagen-induced arthritis model in the rat. The extract showed pharmacological activity and was able to significantly reduce the development of clinical signs of arthritis and markedly reduce the degree of bone resorption, soft tissue swelling and osteophyte formation, preventing articular destruction in treated animals.

  14. Experimental study of canvas characterization for paintings

    Science.gov (United States)

    Cornelis, Bruno; Dooms, Ann; Munteanu, Adrian; Cornelis, Jan; Schelkens, Peter

    2010-02-01

    The work described here fits in the context of a larger project on the objective and relevant characterization of paintings and painting canvas through the analysis of multimodal digital images. We captured, amongst others, X-ray images of different canvas types, characterized by a variety of textures and weave patterns (fine and rougher texture; single thread and multiple threads per weave), including raw canvas as well as canvas processed with different primers. In this paper, we study how to characterize the canvas by extracting global features such as average thread width, average distance between successive threads (i.e. thread density) and the spatial distribution of primers. These features are then used to construct a generic model of the canvas structure. Secondly, we investigate whether we can identify different pieces of canvas coming from the same bolt. This is an important element for dating, authentication and identification of restorations. Both the global characteristics mentioned earlier and some local properties (such as deviations from the average pattern model) are used to compare the "fingerprint" of different pieces of cloth coming from the same or different bolts.

  15. Numerical and experimental characterization of a batch bread baking oven

    International Nuclear Information System (INIS)

    Ploteau, J.P.; Nicolas, V.; Glouannec, P.

    2012-01-01

    This study deals with the thermal characterization of an electrical static oven used for bread baking. The heating is provided by natural convection, infrared radiation and conduction with a cement slab. The paper describes a methodology to apprehend the heat flux which is applied to the products during baking. The oven was experimentally investigated and a finite element numerical model is established. The monitoring of temperatures at various points in the installation and of electrical power is carried out. Then, to characterize thermal exchanges around the bread during curing, thermal responses of a cylindrical sample is also measured. The numerical model made it possible to calculate the heat flux exchanges with the product, while separating the contributions of convection and radiation. The comparison of simulated responses with experimental data shows the relevance of the model. - Highlights: ► This study concerns the thermal characterization of an electric static oven used for bread baking. ► An original, experimental and numerical approach of thermal problem is proposed. ► Contributions by radiation and convection are separated. ► The goal is to provide boundary conditions for numerical models of bread baking. ► Results are encouraging to optimize energy consumption in industrial oven.

  16. Experimental characterization of novel microdiffuser elements

    International Nuclear Information System (INIS)

    Ehrlich, L; Punch, J; Jeffers, N; Stafford, J

    2014-01-01

    Micropumps can play a significant role in thermal management applications, as a component of microfluidic cooling systems. For next-generation high density optical communication systems, in particular, heat flux levels are sufficiently high to require a microfluidic circuit for cooling. Valveless piezoelectrically-actuated micropumps are a particularly promising technology to be deployed for this application. These pumps exploit the asymmetric flow behaviour of microdiffusers to achieve net flow. They feature no rotating or contacting parts, which make them intrinsically reliable in comparison to micropumps with active valves. In this paper, two novel microdiffuser elements are reported and characterized. The micropumps were fabricated using a 3D Printer. Each single diffuser had a length of 1800 pm and a depth of 400 pm. An experimental characterization was conducted in which the flow rate and differential pressure were measured as a function of operating frequency. In comparison with standard diffuser, both elements showed an increase in differential pressure in the range of 40 – 280 %, but only one of the elements exhibited an improved flow rate, of about 85 %.

  17. Design and characterization of a novel neutron shield for BNCT in an experimental model of oral cancer in the hamster cheek pouch at RA-3

    International Nuclear Information System (INIS)

    Pozzi, E.C.C.; Curotto, P.; Monti Hughes, A.; Nigg, D.W.; Schwint, A.E.; Trivillin, V.A.; Thorp, S.I.

    2013-01-01

    Our research group at the Radiation Pathology Division of the Department of Radiobiology (National Atomic Energy Commission) has previously demonstrated the therapeutic efficacy of different BNCT protocols to treat oral cancer in an experimental hamster cheek pouch model. In particular, to perform studies in this experimental model at the thermal facility constructed at RA-3, we designed and constructed a shielding device for thermal neutrons, to be able to expose the cheek pouch while minimizing the dose to the rest of the body. This device allowed for the irradiation of one animal at a time. Given the usage rate of the device, the aim of the present study was to design and construct an optimized version of the existing shielding device that would allow for the simultaneous irradiation of 2 animals at the thermal facility of RA-3. Taking into account the characteristics of the neutron source and preliminary biological assays, we designed the shielding device for the body of the animal, i.e. a rectangular shaped box with double acrylic walls. The space between the walls contains a continuous filling of 6Li 2 CO 3 (95% enriched in 6Li), approximately 6 mm thick. Two small windows interrupt the shield at one end of the box through which the right pouch of each hamster is everted out onto an external acrylic shelf for exposure to the neutron flux. The characterization of the shielding device showed that the neutron flux was equivalent at both irradiation positions confirming that we were able to design and construct a new shielding device that allows for the irradiation of 2 animals at the same time at the thermal facility of RA-3. This new version of the shielding device will reduce the number of interventions of the reactor operators, reducing occupational exposure to radiation and will make the procedure more efficient for researchers. In addition, we addressed the generation of tritium as a product of the capture reaction in lithium. It was considered as a

  18. Experimental characterization, modeling and simulation of a wood pellet micro-combined heat and power unit used as a heat source for a residential building

    Energy Technology Data Exchange (ETDEWEB)

    Thiers, Stephane; Aoun, Bernard; Peuportier, Bruno [MINES ParisTech, CEP - Centre Energetique et Procedes, 60 Boulevard St Michel, 75272 Paris Cedex 06 (France)

    2010-06-15

    Cogeneration provides heat and power in a more efficient way than separate production. Micro-cogeneration (micro-CHP) is an emerging solution for the improvement of energy and environmental assessments of residential buildings. A wood pellet Stirling engine micro-CHP unit has been studied in order to characterize its annual performance when integrated to a building. First, through a test bench experiment, both transient and steady state behaviors of the micro-CHP unit have been characterized and modeled. Then a more complete model representing a hot water and heating system including the micro-CHP unit and a stratified storage tank has been carried out. This model has been coupled to a building model. A sensitivity analysis by simulation shows that the dimensioning of different elements of the system strongly influences its global energy performance. (author)

  19. EXPERIMENTAL MODEL OF THE PRIMARY MALE HYPOGONADISM

    Directory of Open Access Journals (Sweden)

    P. A. Kulikova

    2014-01-01

    Full Text Available Background: Development of the new methods of treatment of primary male hypogonadism is an urgent medical problem. Its solution requires a suitable experimental model of the disease. Aim: The creation of new experimental model of primary male hypogonadism. Materials and methods: The study was conducted on the male Wistar rats, hypogonadism was modeled by temporary ligation of the distal part of the spermatic cord. Results: It was shown that three-day ligation of the spermatic cord led to persistent disturbance of the testosterone-producing and reproductive functions. These manifestations were reversible at shorter duration of the exposure. Conclusion: The created model of primary male hypogonadism is characterized by the persistent testosterone-producing and reproductive functions disturbance, technical availability, non-toxicity to the other organs and systems. Availability of the model provides new opportunities for the development of approaches to treating diseases of the reproductive organs in men.

  20. PEMFC modeling and experimental validation

    Energy Technology Data Exchange (ETDEWEB)

    Vargas, J.V.C. [Federal University of Parana (UFPR), Curitiba, PR (Brazil). Dept. of Mechanical Engineering], E-mail: jvargas@demec.ufpr.br; Ordonez, J.C.; Martins, L.S. [Florida State University, Tallahassee, FL (United States). Center for Advanced Power Systems], Emails: ordonez@caps.fsu.edu, martins@caps.fsu.edu

    2009-07-01

    In this paper, a simplified and comprehensive PEMFC mathematical model introduced in previous studies is experimentally validated. Numerical results are obtained for an existing set of commercial unit PEM fuel cells. The model accounts for pressure drops in the gas channels, and for temperature gradients with respect to space in the flow direction, that are investigated by direct infrared imaging, showing that even at low current operation such gradients are present in fuel cell operation, and therefore should be considered by a PEMFC model, since large coolant flow rates are limited due to induced high pressure drops in the cooling channels. The computed polarization and power curves are directly compared to the experimentally measured ones with good qualitative and quantitative agreement. The combination of accuracy and low computational time allow for the future utilization of the model as a reliable tool for PEMFC simulation, control, design and optimization purposes. (author)

  1. Experimental Modeling of Dynamic Systems

    DEFF Research Database (Denmark)

    Knudsen, Morten Haack

    2006-01-01

    An engineering course, Simulation and Experimental Modeling, has been developed that is based on a method for direct estimation of physical parameters in dynamic systems. Compared with classical system identification, the method appears to be easier to understand, apply, and combine with physical...

  2. Experimental Validation of a Permeability Model for Enrichment Membranes

    International Nuclear Information System (INIS)

    Orellano, Pablo; Brasnarof, Daniel; Florido Pablo

    2003-01-01

    An experimental loop with a real scale diffuser, in a single enrichment-stage configuration, was operated with air at different process conditions, in order to characterize the membrane permeability.Using these experimental data, an analytical geometric-and-morphologic-based model was validated.It is conclude that a new set of independent measurements, i.e. enrichment, is necessary in order to fully characterize diffusers, because of its internal parameters are not univocally determinated with permeability experimental data only

  3. Proposed improvements to a model for characterizing the electrical and thermal energy performance of stirling engine micro-cogeneration devices based upon experimental observations

    Energy Technology Data Exchange (ETDEWEB)

    Lombardi, K. [CanmetENERGY, 1 Haanel Drive, Ottawa, Ont. (Canada); Ugursal, V.I. [Dalhousie University, Halifax, NS (Canada); Beausoleil-Morrison, I. [Carleton University, 1125 Colonel By Drive, Ottawa, Ont. (Canada)

    2010-10-15

    Stirling engines (SE) are a market-ready technology suitable for residential cogeneration of heat and electricity to alleviate the increasing demand on central power grids. Advantages of this external combustion engine include high cogeneration efficiency, fuel flexibility, low noise and vibration, and low emissions. To explore and assess the feasibility of using SE based cogeneration systems in the residential sector, there is a need for an accurate and practical simulation model that can be used to conduct sensitivity and what-if analyses. A simulation model for SE based residential scale micro-cogeneration systems was recently developed; however the model is impractical due to its functional form and data requirements. Furthermore, the available experimental data lack adequate diversity to assess the model's suitability. In this paper, first the existing model is briefly presented, followed by a review of the design and implementation of a series of experiments conducted to study the performance and behaviour of the SE system and to develop extensive, and hitherto unavailable, operational data. The empirical observations are contrasted with the functional form of the existing simulation model, and improvements to the structure of the model are proposed based upon these observations. (author)

  4. Experimental modeling of eddy current inspection capabilities

    International Nuclear Information System (INIS)

    Junker, W.R.; Clark, W.G.

    1984-01-01

    This chapter examines the experimental modeling of eddy current inspection capabilities based upon the use of liquid mercury samples designed to represent metal components containing discontinuities. A brief summary of past work with mercury modeling and a detailed discussion of recent experiments designed to further evaluate the technique are presented. The main disadvantages of the mercury modeling concept are that mercury is toxic and must be handled carefully, liquid mercury can only be used to represent nonferromagnetic materials, and wetting and meniscus problems can distort the effective size of artificial discontinuities. Artificial discontinuities placed in a liquid mercury sample can be used to represent discontinuities in solid metallic structures. Discontinuity size and type cannot be characterized from phase angle and signal amplitude data developed with a surface scanning, pancake-type eddy current probe. It is concluded that the mercury model approach can greatly enhance the overall understanding and applicability of eddy current inspection techniques

  5. Experimental models of developmental hypothyroidism.

    Science.gov (United States)

    Argumedo, G S; Sanz, C R; Olguín, H J

    2012-02-01

    Hypothyroidism is a systemic disease resulting from either thyroid gland's anatomical and functional absence or lack of hypophyseal stimulation, both of which can lead to deficiency in thyroid hormone (TH) production. TH is essential for human and animal development, growth, and function of multiple organs. Children with deficient TH can develop alterations in central nervous system (CNS), striated muscle, bone tissue, liver, bone marrow, and cardiorespiratory system. Among the clinical outlook are signs like breathing difficulty, cardiac insufficiency, dysphagia, and repeated bronchial aspiration, constipation, muscle weakness, cognitive alterations, cochlear dysfunction, reduced height, defects in temperature regulation, anaemia, jaundice, susceptibility to infection, and others. Experimental and clinical studies have shown that TH is very essential for normal brain development. Other research work based on mice pointed out that a reduced level of TH in pregnant mother leads to congenital hypothyroidism in animal models and it is associated with mental retardation, deep neurologic deficiency that impacts on cognitive, learning, and memory functions. The principal experimental model studies that have focused on hypothyroidism are reviewed in this study. This is important on considering the fact that almost all animal species require thyroid hormones for their metabolism. © Georg Thieme Verlag KG Stuttgart · New York.

  6. Experimental Characterization and Material Modelling of an AZ31 Magnesium Sheet Alloy at Elevated Temperatures under Consideration of the Tension-Compression Asymmetry

    Science.gov (United States)

    Behrens, B.-A.; Bouguecha, A.; Bonk, C.; Dykiert, M.

    2017-09-01

    Magnesium sheet alloys have a great potential as a construction material in the aerospace and automotive industry. However, the current state of research regarding temperature dependent material parameters for the description of the plastic behaviour of magnesium sheet alloys is scarce in literature and accurate statements concerning yield criteria and appropriate characterization tests to describe the plastic behaviour of a magnesium sheet alloy at elevated temperatures in deep drawing processes are to define. Hence, in this paper the plastic behaviour of the well-established magnesium sheet alloy AZ31 has been characterized by means of convenient mechanical tests (e. g. tension, compression and biaxial tests) at temperatures between 180 and 230 °C. In this manner, anisotropic and hardening behaviour as well as differences between the tension-compression asymmetry of the yield locus have been estimated. Furthermore, using the evaluated data from the above mentioned tests, two different yield criteria have been parametrized; the commonly used Hill’48 and an orthotropic yield criterion, CPB2006, which was developed especially for materials with hexagonal close packed lattice structure and is able to describe an asymmetrical yielding behaviour regarding tensile and compressive stress states. Numerical simulations have been finally carried out with both yield functions in order to assess the accuracy of the material models.

  7. Experimental and computing strategies in advanced material characterization problems

    Energy Technology Data Exchange (ETDEWEB)

    Bolzon, G. [Department of Civil and Environmental Engineering, Politecnico di Milano, piazza Leonardo da Vinci 32, 20133 Milano, Italy gabriella.bolzon@polimi.it (Italy)

    2015-10-28

    The mechanical characterization of materials relies more and more often on sophisticated experimental methods that permit to acquire a large amount of data and, contemporarily, to reduce the invasiveness of the tests. This evolution accompanies the growing demand of non-destructive diagnostic tools that assess the safety level of components in use in structures and infrastructures, for instance in the strategic energy sector. Advanced material systems and properties that are not amenable to traditional techniques, for instance thin layered structures and their adhesion on the relevant substrates, can be also characterized by means of combined experimental-numerical tools elaborating data acquired by full-field measurement techniques. In this context, parameter identification procedures involve the repeated simulation of the laboratory or in situ tests by sophisticated and usually expensive non-linear analyses while, in some situation, reliable and accurate results would be required in real time. The effectiveness and the filtering capabilities of reduced models based on decomposition and interpolation techniques can be profitably used to meet these conflicting requirements. This communication intends to summarize some results recently achieved in this field by the author and her co-workers. The aim is to foster further interaction between engineering and mathematical communities.

  8. Experimental and computing strategies in advanced material characterization problems

    International Nuclear Information System (INIS)

    Bolzon, G.

    2015-01-01

    The mechanical characterization of materials relies more and more often on sophisticated experimental methods that permit to acquire a large amount of data and, contemporarily, to reduce the invasiveness of the tests. This evolution accompanies the growing demand of non-destructive diagnostic tools that assess the safety level of components in use in structures and infrastructures, for instance in the strategic energy sector. Advanced material systems and properties that are not amenable to traditional techniques, for instance thin layered structures and their adhesion on the relevant substrates, can be also characterized by means of combined experimental-numerical tools elaborating data acquired by full-field measurement techniques. In this context, parameter identification procedures involve the repeated simulation of the laboratory or in situ tests by sophisticated and usually expensive non-linear analyses while, in some situation, reliable and accurate results would be required in real time. The effectiveness and the filtering capabilities of reduced models based on decomposition and interpolation techniques can be profitably used to meet these conflicting requirements. This communication intends to summarize some results recently achieved in this field by the author and her co-workers. The aim is to foster further interaction between engineering and mathematical communities

  9. Experimental Setup to Characterize Bentonite Hydration Processes

    International Nuclear Information System (INIS)

    Bru, A.; Casero, D.; Pastor, J. M.

    2001-01-01

    We present an experimental setup to follow-up the hydration process of a bentonite. Clay samples, of 2 cm x 12 cm x 12 cm, were made and introduced in a Hele-Shaw cell with two PMM windows and two steel frames. In hydration experiments, a fluid enters by an orifice in the frame, located both at the top and the bottom of the cell, to perform hydration in both senses. To get a uniform hydration we place a diffuser near the orifice. Volume influxes in hydration cells are registered in time. The evolution of the developed interface was recorded on a videotape. The video cameras was fixed to a holder so that the vertical direction in the monitor was the same as the direction of the larger extension of the cell. (Author) 6 refs

  10. Neutropenia induced in outbred mice by a simplified low-dose cyclophosphamide regimen: characterization and applicability to diverse experimental models of infectious diseases

    Directory of Open Access Journals (Sweden)

    Zapata Ana X

    2006-03-01

    Full Text Available Abstract Background For its low cost and ease of handling, the mouse remains the preferred experimental animal for preclinical tests. To avoid the interaction of the animal immune system, in vivo antibiotic pharmacodynamic studies often employ cyclophosphamide (CPM to induce neutropenia. Although high doses (350–450 mg/kg are still used and their effects on mouse leukocytes have been described, a lower dose (250 mg/kg is widely preferred today, but the characteristics and applicability of this approach in outbred mice have not been determined. Methods Fifteen female ICR mice were injected intraperitoneally with 150 and 100 mg/kg of CPM on days 1 and 4, respectively. Blood samples (~160 μL were drawn from the retro-orbital sinus of each mouse on days 1, 4, 5, 6, 7 and 11. Leukocytes were counted manually and the number of granulocytes was based on microscopic examination of Wright-stained smears. The impact of neutropenia induced by this method was then determined with a variety of pathogens in three different murine models of human infections: pneumonia (Klebsiella pneumoniae, Streptococcus pneumoniae, Staphylococcus aureus, meningoencephalitis (S. pneumoniae, and the thigh model (S. aureus, Escherichia coli, Bacteroides fragilis. Results The basal count of leukocytes was within the normal range for outbred mice. On day 4, there was an 84% reduction in total white blood cells, and by day 5 the leukopenia reached its nadir (370 ± 84 cells/mm3. Profound neutropenia (≤10 neutrophils/mm3 was demonstrated at day 4 and persisted through days 5 and 6. Lymphocytes and monocytes had a 92% and 96% decline between days 1 and 5, respectively. Leukocytes recovered completely by day 11. Mice immunosupressed under this protocol displayed clinical and microbiological patterns of progressive and lethal infectious diseases after inoculation in different organs with diverse human pathogens. Conclusion A CPM total dose of 250 mg/kg is sufficient to induce

  11. Experimental models of liver fibrosis.

    Science.gov (United States)

    Yanguas, Sara Crespo; Cogliati, Bruno; Willebrords, Joost; Maes, Michaël; Colle, Isabelle; van den Bossche, Bert; de Oliveira, Claudia Pinto Marques Souza; Andraus, Wellington; Alves, Venâncio Avancini Ferreira; Leclercq, Isabelle; Vinken, Mathieu

    2016-05-01

    Hepatic fibrosis is a wound healing response to insults and as such affects the entire world population. In industrialized countries, the main causes of liver fibrosis include alcohol abuse, chronic hepatitis virus infection and non-alcoholic steatohepatitis. A central event in liver fibrosis is the activation of hepatic stellate cells, which is triggered by a plethora of signaling pathways. Liver fibrosis can progress into more severe stages, known as cirrhosis, when liver acini are substituted by nodules, and further to hepatocellular carcinoma. Considerable efforts are currently devoted to liver fibrosis research, not only with the goal of further elucidating the molecular mechanisms that drive this disease, but equally in view of establishing effective diagnostic and therapeutic strategies. The present paper provides a state-of-the-art overview of in vivo and in vitro models used in the field of experimental liver fibrosis research.

  12. IVIM: modeling, experimental validation and application to animal models

    International Nuclear Information System (INIS)

    Fournet, Gabrielle

    2016-01-01

    This PhD thesis is centered on the study of the IVIM ('Intravoxel Incoherent Motion') MRI sequence. This sequence allows for the study of the blood microvasculature such as the capillaries, arterioles and venules. To be sensitive only to moving groups of spins, diffusion gradients are added before and after the 180 degrees pulse of a spin echo (SE) sequence. The signal component corresponding to spins diffusing in the tissue can be separated from the one related to spins travelling in the blood vessels which is called the IVIM signal. These two components are weighted by f IVIM which represents the volume fraction of blood inside the tissue. The IVIM signal is usually modelled by a mono-exponential (ME) function and characterized by a pseudo-diffusion coefficient, D*. We propose instead a bi-exponential IVIM model consisting of a slow pool, characterized by F slow and D* slow corresponding to the capillaries as in the ME model, and a fast pool, characterized by F fast and D* fast, related to larger vessels such as medium-size arterioles and venules. This model was validated experimentally and more information was retrieved by comparing the experimental signals to a dictionary of simulated IVIM signals. The influence of the pulse sequence, the repetition time and the diffusion encoding time was also studied. Finally, the IVIM sequence was applied to the study of an animal model of Alzheimer's disease. (author) [fr

  13. experimental viscoelastic characterization of corn cob composites ...

    African Journals Online (AJOL)

    Dr Obe

    sufficient to represent the viscoelastic behavior of the corn cob. The effect of moisture content and rates of loading on the mechanical model determined were investigated. 1. ..... F = applied force or residual force σ. = contact stress .... J. Agric. Engineering. Res. 7(4):. 300-315. Journal of the British Society for. Research in ...

  14. Characterization of experimental dental research using animals

    Directory of Open Access Journals (Sweden)

    Ana Flávia Granville-Garcia

    2009-01-01

    Full Text Available Objective: To determine the profile of experimental dental research using animals. Methods: The research comprised all the 4141 abstracts existent in the books of annals from the 22nd and 23rd Annual meetings of the Brazilian Society of Dentistry Research and the sample was composed of 377 studies (9.1%. The variables analyzed were: area of knowledge, type of institution, State of the country, type of animal and body part used, occurrence of animal sacrifice, mention of the Research Ethics Committee, receipt of funding and type of financing agency. Results: The largest number of studies concentrated on the areas of Buccomaxillofacial Surgery (27.3% and Basic Sciences (21.2%. The Public Universities were responsible for 74% of the researches, and the State Institutions were outstanding (82.4%. The State of São Paulo was responsible for 74.1% of the studies. Rats (67.1% and rabbits (11.1% were the most frequently used animals, and 68.2% of the animals were sacrificed. The oral cavity was used in 50.1% of the researches and the mandible in 59%. Only 1.9% of the studies mentioned the Research Ethics Committee and 26.3% reported that they received funding. Conclusion: In Dentistry, studies involving animals are predominant in the areas of buccomaxillofacial surgery and basic sciences, with rats andrabbits being most frequently used. A significant number of guinea pigs are sacrificed during or at the end of the experiments.

  15. Wellbore Microannulus Characterization and Modeling.

    Energy Technology Data Exchange (ETDEWEB)

    Matteo, Edward N; Sobolik, Steven R.; Stormont, John C.; Taha, Mahmoud Reda; Gomez, Steven Paul

    2016-05-01

    Subsurface geologic formations used for extracting resources such as oil and gas can subsequently be used as a storage reservoir for the common greenhouse gas CO2, a concept known as Carbon Capture and Storage (CCS). Pre-existing wellbores penetrate the reservoirs where supercritical CO2 is to be injected. These wellbores can potentially be a pathway for contamination if CO2 leaks through wellbore flaws to an overlying aquifer or the atmosphere. Characterizing wellbore integrity and providing zonal isolation by repairing these wellbore flaws is of critical importance to the long-term isolation of CO2 and success of CCS. This research aims to characterize the microannulus region of the cement sheath-steel casing interface in terms of its compressibility and permeability. A mock-up of a wellbore system was used for lab-scale testing. Specimens, consisting of a cement sheath cast on a steel casing with microannuli, were subjected to confining pressures and casing pressures in a pressure vessel that allows simultaneous measurement of gas flow along the axis of the specimen. The flow was interpreted as the hydraulic aperture of the microannuli. Numerical models are used to analyze stress and displacement conditions along the casing-cement interface. These numerical results provide good agreement with closed-form elastic solutions. Numerical models incorporating flaws of varying dimensions along the casing-cement interface were then developed to describe the microannulus region. A joint model is used to describe the hydraulic aperture of the microannulus region, whose mechanical stiffness is altered in response to the imposed stress state across the joint interface. The aperture-stress behavior is based upon laboratory measurements of hydraulic aperture as a function of imposed stress conditions. This investigation found that microannulus permeability can satisfactorily be described by a joint model and that the constitutive

  16. Experimental and Computational Characterization of Combustion Phenomena

    Science.gov (United States)

    2006-05-01

    combustors without installing glass , quartz, or sapphire windows when using terahertz radiation. To explore the potential diagnostics utility of T...laser was reduced using a Spectra-Physics Model 3980 pulse selector. This device employs a TeO2 acousto-optic modulator to select subsets of pulses...equipped with a UG-11 and two WG-295 colored glass filters to reduce visible and laser-scattered light, respectively. OH-PLIF images were acquired

  17. Micromechanical finite element modeling and experimental characterization of the compressive mechanical properties of polycaprolactone:hydroxyapatite composite scaffolds prepared by selective laser sintering for bone tissue engineering

    Science.gov (United States)

    Eshraghi, Shaun; Das, Suman

    2012-01-01

    Bioresorbable scaffolds with mechanical properties suitable for bone tissue engineering were fabricated from polycaprolactone (PCL) and hydroxyapatite (HA) by selective laser sintering (SLS) and modeled by finite element analysis (FEA). Both solid gage parts and scaffolds having 1-D, 2-D and 3-D orthogonal, periodic porous architectures were made with 0, 10, 20 and 30% HA by volume. PCL:HA scaffolds manufactured by SLS had nearly full density (99%) in the designed solid regions and had excellent geometric and dimensional control. Through optimization of the SLS process, the compressive moduli for our solid gage parts and scaffolds are the highest reported in the literature for additive manufacturing. The compressive moduli of solid gage parts were 299.3, 311.2, 415.5 and 498.3 MPa for PCL:HA loading at 100:0, 90:10, 80:20 and 70:30 respectively. The compressive effective stiffness tended to increase as the loading of HA was increased and the designed porosity was lowered. In the case of the most 3-D porous scaffold, the compressive modulus more than doubled from 14.9 MPa to 36.2 MPa when changing the material from 100:0 to 70:30 PCL:HA. A micromechanical finite element analysis (FEA) model was developed to investigate the reinforcement effect of HA loading on the compressive modulus of the bulk material. Using a first-principles based approach, the random distribution of HA particles in a solidified PCL matrix was modeled for any loading of HA to predict the bulk mechanical properties of the composites. The bulk mechanical properties were also used for FEA of the scaffold geometries. Results of the FEA were found to be in good agreement with experimental mechanical testing. The development of patient and site-specific composite tissue engineering constructs with tailored properties can be seen as a direct extension of this work on computational design, a priori modeling of mechanical properties and direct digital manufacturing. PMID:22522129

  18. Micromechanical finite-element modeling and experimental characterization of the compressive mechanical properties of polycaprolactone-hydroxyapatite composite scaffolds prepared by selective laser sintering for bone tissue engineering.

    Science.gov (United States)

    Eshraghi, Shaun; Das, Suman

    2012-08-01

    Bioresorbable scaffolds with mechanical properties suitable for bone tissue engineering were fabricated from polycaprolactone (PCL) and hydroxyapatite (HA) by selective laser sintering (SLS) and modeled by finite-element analysis (FEA). Both solid gage parts and scaffolds having 1-D, 2-D and 3-D orthogonal, periodic porous architectures were made with 0, 10, 20 and 30 vol.% HA. PCL:HA scaffolds manufactured by SLS had nearly full density (99%) in the designed solid regions and had excellent geometric and dimensional control. Through optimization of the SLS process, the compressive moduli for our solid gage parts and scaffolds are the highest reported in the literature for additive manufacturing. The compressive moduli of solid gage parts were 299.3, 311.2, 415.5 and 498.3 MPa for PCL:HA loading at 100:0, 90:10, 80:20 and 70:30, respectively. The compressive effective stiffness tended to increase as the loading of HA was increased and the designed porosity was lowered. In the case of the most 3-D porous scaffold, the compressive modulus more than doubled from 14.9 to 36.2 MPa when changing the material from 100:0 to 70:30 PCL:HA. A micromechanical FEA model was developed to investigate the reinforcement effect of HA loading on the compressive modulus of the bulk material. Using a first-principles based approach, the random distribution of HA particles in a solidified PCL matrix was modeled for any HA loading to predict the bulk mechanical properties of the composites. The bulk mechanical properties were also used for FEA of the scaffold geometries. The results of the FEA were found to be in good agreement with experimental mechanical testing. The development of patient- and site-specific composite tissue-engineering constructs with tailored properties can be seen as a direct extension of this work on computational design, a priori modeling of mechanical properties and direct digital manufacturing. Copyright © 2012 Acta Materialia Inc. Published by Elsevier Ltd. All

  19. Experimental characterization of methane inverse diffusion flame

    KAUST Repository

    Elbaz, Ayman M.

    2014-06-26

    This article presents 10-kHz images of OH-PLIF simultaneously with 2-D PIV measurements in an inverse methane diffusion flame. Under a constant fuel flow rate, the central air jet Re was varied, leading to air to fuel velocity ratio, Vr, to vary from 8.3 to 66.5. Starting from Vr = 20.7, the flame is commonly characterized by three distinct zones. The length of the lower fuel entrainment region is inversely proportional to Vr. The flames investigated resemble a string shear layer confining this zone, and converging into the second distinct region, the flame neck zone. The third region is the rest of the flame, which spreads in a jet-like manner. The inverse diffusion flames exhibit varying degrees of partial premixing, depending upon on the velocity ratio Vr, and this region of partial premixing evolves into a well-mixed reaction zone along the flame centerline. The OH distribution correlated with the changes in the mean characteristics of the flow through reduction in the local Reynolds number due to heat release. The existence of a flame suppresses or laminarizes the turbulence at early axial locations and promotes fluctuations at the flame tip for flames with Vr < 49.8. In addition, the flame jet width can be correlated to the OH distribution. In upstream regions of the flames, the breaks in OH are counterbalanced by flame closures and are governed by edge flame propagation. These local extinctions were found to occur at locations where large flow structures were impinging on the flame and are associated with a locally higher strain rate or correlated to the local high strain rates at the flame hole edges without this flow impinging. Another contributor to re-ignition was found to be growing flame kernels. As the flames approach global blow-off, these kernels become the main mechanism for re-ignition further downstream of the flames. At low Vr, laminarization within the early regions of the flame provides an effective shield, preventing the jet flow from

  20. A combination of experimental measurement, constitutive damage model, and diffusion tensor imaging to characterize the mechanical properties of the human brain.

    Science.gov (United States)

    Karimi, Alireza; Rahmati, Seyed Mohammadali; Razaghi, Reza

    2017-09-01

    Understanding the mechanical properties of the human brain is deemed important as it may subject to various types of complex loadings during the Traumatic Brain Injury (TBI). Although many studies so far have been conducted to quantify the mechanical properties of the brain, there is a paucity of knowledge on the mechanical properties of the human brain tissue and the damage of its axon fibers under the various types of complex loadings during the Traumatic Brain Injury (TBI). Although many studies so far have been conducted to quantify the mechanical properties of the brain, there is a paucity of knowledge on the mechanical properties of the human brain tissue and the damage of its axon fibers under the frontal lobe of the human brain. The constrained nonlinear minimization method was employed to identify the brain coefficients according to the axial and transversal compressive data. The pseudo-elastic damage model data was also well compared with that of the experimental data and it not only up to the primary loading but also the discontinuous softening could well address the mechanical behavior of the brain tissue.

  1. Thermal and Pressure Characterization of a Wind Tunnel Force Balance Using the Single Vector System. Experimental Design and Analysis Approach to Model Pressure and Temperature Effects in Hypersonic Wind Tunnel Research

    Science.gov (United States)

    Lynn, Keith C.; Commo, Sean A.; Johnson, Thomas H.; Parker, Peter A,

    2011-01-01

    Wind tunnel research at NASA Langley Research Center s 31-inch Mach 10 hypersonic facility utilized a 5-component force balance, which provided a pressurized flow-thru capability to the test article. The goal of the research was to determine the interaction effects between the free-stream flow and the exit flow from the reaction control system on the Mars Science Laboratory aeroshell during planetary entry. In the wind tunnel, the balance was exposed to aerodynamic forces and moments, steady-state and transient thermal gradients, and various internal balance cavity pressures. Historically, these effects on force measurement accuracy have not been fully characterized due to limitations in the calibration apparatus. A statistically designed experiment was developed to adequately characterize the behavior of the balance over the expected wind tunnel operating ranges (forces/moments, temperatures, and pressures). The experimental design was based on a Taylor-series expansion in the seven factors for the mathematical models. Model inversion was required to calculate the aerodynamic forces and moments as a function of the strain-gage readings. Details regarding transducer on-board compensation techniques, experimental design development, mathematical modeling, and wind tunnel data reduction are included in this paper.

  2. EXPERIMENTAL MEASUREMENT, ANALYSIS AND MODELLING ...

    African Journals Online (AJOL)

    30 juin 2010 ... We obtain a good agreement between the resolution of the nonlinear equation of heat and the results obtained by the experimentation. . Keywords: Emissivity, Température, optimal Linearisation, finite elements. 1. ..... basse température, Rapport de Stage de D.E.A, Université Paris 12 – Val de Marne.

  3. Experimental Oral Candidiasis in Animal Models

    Science.gov (United States)

    Samaranayake, Yuthika H.; Samaranayake, Lakshman P.

    2001-01-01

    Oral candidiasis is as much the final outcome of the vulnerability of the host as of the virulence of the invading organism. We review here the extensive literature on animal experiments mainly appertaining to the host predisposing factors that initiate and perpetuate these infections. The monkey, rat, and mouse are the choice models for investigating oral candidiasis, but comparisons between the same or different models appear difficult, because of variables such as the study design, the number of animals used, their diet, the differences in Candida strains, and the duration of the studies. These variables notwithstanding, the following could be concluded. (i) The primate model is ideal for investigating Candida-associated denture stomatitis since both erythematous and pseudomembranous lesions have been produced in monkeys with prosthetic plates; they are, however, expensive and difficult to obtain and maintain. (ii) The rat model (both Sprague-Dawley and Wistar) is well proven for observing chronic oral candidal colonization and infection, due to the ease of breeding and handling and their ready availability. (iii) Mice are similar, but in addition there are well characterized variants simulating immunologic and genetic abnormalities (e.g., athymic, euthymic, murine-acquired immune deficiency syndrome, and severe combined immunodeficient models) and hence are used for short-term studies relating the host immune response and oral candidiasis. Nonetheless, an ideal, relatively inexpensive model representative of the human oral environment in ecological and microbiological terms is yet to be described. Until such a model is developed, researchers should pay attention to standardization of the experimental protocols described here to obtain broadly comparable and meaningful data. PMID:11292645

  4. Experimental models of autoimmune inflammatory ocular diseases

    Directory of Open Access Journals (Sweden)

    Fabio Gasparin

    2012-04-01

    Full Text Available Ocular inflammation is one of the leading causes of blindness and loss of vision. Human uveitis is a complex and heterogeneous group of diseases characterized by inflammation of intraocular tissues. The eye may be the only organ involved, or uveitis may be part of a systemic disease. A significant number of cases are of unknown etiology and are labeled idiopathic. Animal models have been developed to the study of the physiopathogenesis of autoimmune uveitis due to the difficulty in obtaining human eye inflamed tissues for experiments. Most of those models are induced by injection of specific photoreceptors proteins (e.g., S-antigen, interphotoreceptor retinoid-binding protein, rhodopsin, recoverin, phosducin. Non-retinal antigens, including melanin-associated proteins and myelin basic protein, are also good inducers of uveitis in animals. Understanding the basic mechanisms and pathogenesis of autoimmune ocular diseases are essential for the development of new treatment approaches and therapeutic agents. The present review describes the main experimental models of autoimmune ocular inflammatory diseases.

  5. Computerized simulation of YAG pulse laser welding of titanium alloy (TA6V): experimental characterization and modelling of the thermomechanical aspects of this process

    International Nuclear Information System (INIS)

    Robert, Y.

    2007-09-01

    This work is a part of study which goal is to realize a computer modelling of the thermomechanical phenomena occurring during the YAG pulse laser welding of titanium alloy (TA6V). The filet welding has different heterogeneities (microstructural and mechanical). In fact, the temperature causes microstructural changes (phase transformations, precipitations) and modifies the mechanical properties. Thermomechanical modelling has thus to be established for the welding of TA6V. (author)

  6. Novel sensors for food inspection modelling, fabrication and experimentation

    CERN Document Server

    Abdul Rahman, Mohd Syaifudin; Yu, Pak-Lam

    2014-01-01

    This book addresses presents recent developments of novel planar interdigital sensors for food inspection. It covers the fundamentals of sensors, their design, modelling and simulations, fabrications, characterizations, experimental investigations and analyses. This book will be useful for the engineers and researchers especially higher undergraduate, postgraduate students as well as practitioners working on the development of Electromagnetic Sensors.

  7. Experimental Flight Characterization of a Canard-Controlled, Subsonic Missile

    Science.gov (United States)

    2017-08-01

    Frankfort mount was used to place the gun between stations 5 and 6 in the spark range building. The propelling charge was contained within a plastic ...additive manufacturing housing and used 83 g of M38 propellant with about 2 g of black powder wrapped around an electric match. A shot-start link was...ARL-TR-8086 ● AUG 2017 US Army Research Laboratory Experimental Flight Characterization of a Canard-Controlled, Subsonic Missile

  8. Experimental Characterization of Supercavitating Finds Piercing a Ventilated Supercavity

    Science.gov (United States)

    2013-08-05

    01-2011 --31-07-2013 4. TITLE AND SUBTITLE Sa. CONTRACT NUMBER Experimental Characterization of Supercavitating Finds Piercing a Ventilated...presents the results from water tunnel experiments on supercavitating fins performed at the Garfield Thomas Water Tunnel of the Pennsylvania State...SUBJECT TERMS supercavitation , fins, cavity-piercing 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF ABSTRACT u a. REPORT I~· ABSTRACT I~· THIS

  9. Developing Phenomena Models from Experimental Data

    DEFF Research Database (Denmark)

    Kristensen, Niels Rode; Madsen, Henrik; Jørgensen, Sten Bay

    2003-01-01

    A systematic approach for developing phenomena models from experimental data is presented. The approach is based on integrated application of stochastic differential equation (SDE) modelling and multivariate nonparametric regression, and it is shown how these techniques can be used to uncover...... unknown functionality behind various phenomena in first engineering principles models using experimental data. The proposed modelling approach has significant application potential, e.g. for determining unknown reaction kinetics in both chemical and biological processes. To illustrate the performance...... of the approach, a case study is presented, which shows how an appropriate phenomena model for the growth rate of biomass in a fed-batch bioreactor can be inferred from data....

  10. Developing Phenomena Models from Experimental Data

    DEFF Research Database (Denmark)

    A systematic approach for developing phenomena models from experimental data is presented. The approach is based on integrated application of stochastic differential equation (SDE) modelling and multivariate nonparametric regression, and it is shown how these techniques can be used to uncover...... unknown functionality behind various phenomena in first engineering principles models using experimental data. The proposed modelling approach has significant application potential, e.g. for determining unknown reaction kinetics in both chemical and biological processes. To illustrate the performance...... of the approach, a case study is presented, which shows how an appropriate phenomena model for the growth rate of biomass in a fed-batch bioreactor can be inferred from data....

  11. Experimental models of demyelination and remyelination.

    Science.gov (United States)

    Torre-Fuentes, L; Moreno-Jiménez, L; Pytel, V; Matías-Guiu, J A; Gómez-Pinedo, U; Matías-Guiu, J

    2017-08-29

    Experimental animal models constitute a useful tool to deepen our knowledge of central nervous system disorders. In the case of multiple sclerosis, however, there is no such specific model able to provide an overview of the disease; multiple models covering the different pathophysiological features of the disease are therefore necessary. We reviewed the different in vitro and in vivo experimental models used in multiple sclerosis research. Concerning in vitro models, we analysed cell cultures and slice models. As for in vivo models, we examined such models of autoimmunity and inflammation as experimental allergic encephalitis in different animals and virus-induced demyelinating diseases. Furthermore, we analysed models of demyelination and remyelination, including chemical lesions caused by cuprizone, lysolecithin, and ethidium bromide; zebrafish; and transgenic models. Experimental models provide a deeper understanding of the different pathogenic mechanisms involved in multiple sclerosis. Choosing one model or another depends on the specific aims of the study. Copyright © 2017 Sociedad Española de Neurología. Publicado por Elsevier España, S.L.U. All rights reserved.

  12. Experimental Characterization and Cohesive Laws for Delamination of Off-Axis GFRP Laminates

    DEFF Research Database (Denmark)

    Lindgaard, Esben; Bak, Brian Lau Verndal

    2015-01-01

    This work experimentally characterizes mixed mode delamination in glass fibre reinforced polymer laminates taking into account the influence of the off-axis angle between the lamina orientation and the crack growth direction on the fracture properties. Thus, providing a cohesive law that enables...... analysis of 3D models in which mixed mode crack growth within laminates having anisotropic fracture properties takes place....

  13. Improving the physiological realism of experimental models.

    Science.gov (United States)

    Vinnakota, Kalyan C; Cha, Chae Y; Rorsman, Patrik; Balaban, Robert S; La Gerche, Andre; Wade-Martins, Richard; Beard, Daniel A; Jeneson, Jeroen A L

    2016-04-06

    The Virtual Physiological Human (VPH) project aims to develop integrative, explanatory and predictive computational models (C-Models) as numerical investigational tools to study disease, identify and design effective therapies and provide an in silico platform for drug screening. Ultimately, these models rely on the analysis and integration of experimental data. As such, the success of VPH depends on the availability of physiologically realistic experimental models (E-Models) of human organ function that can be parametrized to test the numerical models. Here, the current state of suitable E-models, ranging from in vitro non-human cell organelles to in vivo human organ systems, is discussed. Specifically, challenges and recent progress in improving the physiological realism of E-models that may benefit the VPH project are highlighted and discussed using examples from the field of research on cardiovascular disease, musculoskeletal disorders, diabetes and Parkinson's disease.

  14. Design and experimental characterization of an EM pump

    International Nuclear Information System (INIS)

    Kim, Hee Reyoung; Hong, Sang Hee

    1999-01-01

    Generally, an EM (electromagnetic) pump is been employed to circulate electrically conducting liquids by using the Lorentz force. Especially, at the liquid metal reactor (LMR), which uses liquid sodium with high electrical conductivity as a coolant, an EM pump is needed due to its advantages over a mechanical pump, such as no rotating parts, no noise, and simplicity. In this research, an EM pump of a pilot annular linear induction type with a flow rate of 200 l/min was designed by using the electrical equivalent-circuit method. The pump was designed and manufactured by considering material and environmental (high temperature and liquid sodium) requirements. The pump performance was experimentally characterized based on input currents, voltage, power, and frequency. Also, the theoretical prediction was compared with the experimental result

  15. Understanding Leadership: An Experimental-Experiential Model

    Science.gov (United States)

    Hole, George T.

    2014-01-01

    Books about leadership are dangerous to readers who fantasize about being leaders or apply leadership ideas as if they were proven formulas. As an antidote, I offer an experimental framework in which any leadership-management model can be tested to gain experiential understanding of the model. As a result one can gain reality-based insights about…

  16. Thermodynamics of binary mixtures of N-methyl-2-pyrrolidinone and ketone. Experimental results and modelling of the (solid + liquid) equilibrium and the (vapour + liquid) equilibrium. The modified UNIFAC (Do) model characterization

    International Nuclear Information System (INIS)

    Domanska, Urszula; Lachwa, Joanna

    2005-01-01

    The (solid + liquid) equilibrium (SLE) of eight binary systems containing N-methyl-2-pyrrolidinone (NMP) with (2-propanone, or 2-butanone, or 2-pentanone, or 3-pentanone, or cyclopentanone, or 2-hexanone, or 4-methyl-2-pentanone, or 3-heptanone) were carried out by using a dynamic method from T = 200 K to the melting point of the NMP. The isothermal (vapour + liquid) equilibrium data (VLE) have been measured for three binary mixtures of NMP with 2-propanone, 3-pentanone and 2-hexanone at pressure range from p = 0 kPa to p = 115 kPa. Data were obtained at the temperature T = 333.15 K for the first system and at T = 373.15 K for the second two systems. The experimental results of SLE have been correlated using the binary parameters Wilson, UNIQUAC ASM and two modified NRTL equations. The root-mean-square deviations of the solubility temperatures for all the calculated values vary from (0.32 K to 0.68 K) and depend on the particular equation used. The data of VLE were correlated with one to three parameters in the Redlich-Kister expansion. Binary mixtures of NMP with (2-propanone, or 2-butanone, or 2-pentanone, or 3-pentanone, or cyclopentanone, or 2-hexanone, or 4-methyl-2-pentanone, or 3-heptanone) have been investigated in the framework of the modified UNIFAC (Do) model. The reported new interaction parameters for NMP-group (c-CONCH 3 ) and carbonyl group ( C=O) let the model consistently described a set of thermodynamic properties, including (solid + liquid) equilibrium (vapour + liquid) equilibrium, excess Gibbs energy and molar excess enthalpies of mixing. Our experimental and literature data of binary mixtures containing NMP and ketones were compared with the results of prediction with the modified UNIFAC (Do) model

  17. Analytical and Experimental Characterization of Thick-Section Fiber-Metal Laminates

    Science.gov (United States)

    2013-06-01

    laminate . The model individually models each layer of the laminate and predicts stiffness degradation as metal layers plastically deform and as prepreg ...eliminating four of the possible ECM laminates . Additionally, since at least four individual layers (two aluminum and two prepreg ) are used in FML an...AFRL-AFOSR-UK-TR-2013-0023 Analytical and Experimental Characterization of Thick- Section Fiber-Metal Laminates Dr. Rene

  18. Characterizing and Modeling Citation Dynamics

    Science.gov (United States)

    Eom, Young-Ho; Fortunato, Santo

    2011-01-01

    Citation distributions are crucial for the analysis and modeling of the activity of scientists. We investigated bibliometric data of papers published in journals of the American Physical Society, searching for the type of function which best describes the observed citation distributions. We used the goodness of fit with Kolmogorov-Smirnov statistics for three classes of functions: log-normal, simple power law and shifted power law. The shifted power law turns out to be the most reliable hypothesis for all citation networks we derived, which correspond to different time spans. We find that citation dynamics is characterized by bursts, usually occurring within a few years since publication of a paper, and the burst size spans several orders of magnitude. We also investigated the microscopic mechanisms for the evolution of citation networks, by proposing a linear preferential attachment with time dependent initial attractiveness. The model successfully reproduces the empirical citation distributions and accounts for the presence of citation bursts as well. PMID:21966387

  19. Biaxial experimental and analytical characterization of a dielectric elastomer

    Science.gov (United States)

    Helal, Alexander; Doumit, Marc; Shaheen, Robert

    2018-01-01

    Electroactive polymers (EAPs) have emerged as a strong contender for use in low-cost efficient actuators in multiple applications especially related to biomimetic and mobile-assistive devices. Dielectric elastomers (DE), a subcategory of these smart materials, have been of particular interest due to their large achievable deformation and favourable mechanical and electro-mechanical properties. Previous work has been completed to understand the behaviour of these materials; however, their properties require further investigation to properly integrate them into real-world applications. In this study, a biaxial tensile experimental evaluation of 3M™ VHB 4905 and VHB 4910 is presented with the purpose of illustrating the elastomers' transversely isotropic mechanical behaviours. These tests were applied to both tapes for equibiaxial stretch rates ranging between 0.025 and 0.300 s-1. Subsequently, a dynamic planar biaxial visco-hyperelastic constitutive relationship was derived from a Kelvin-Voigt rheological model and the general Hooke's law for transversely isotropic materials. The model was then fitted to the experimental data to obtain three general material parameters for either tapes. The model's ability to predict tensile stress response and internal energy dissipation, with respect to experimental data, is evaluated with good agreement. The model's ability to predict variations in mechanical behaviour due to changes in kinematic variables is then illustrated for different conditions.

  20. Simulation and Experimental Characterization of Microscopically Accessible Hydrodynamic Microvortices

    Directory of Open Access Journals (Sweden)

    Deirdre R. Meldrum

    2012-06-01

    Full Text Available Single-cell studies of phenotypic heterogeneity reveal more information about pathogenic processes than conventional bulk-cell analysis methods. By enabling high-resolution structural and functional imaging, a single-cell three-dimensional (3D imaging system can be used to study basic biological processes and to diagnose diseases such as cancer at an early stage. One mechanism that such systems apply to accomplish 3D imaging is rotation of a single cell about a fixed axis. However, many cell rotation mechanisms require intricate and tedious microfabrication, or fail to provide a suitable environment for living cells. To address these and related challenges, we applied numerical simulation methods to design new microfluidic chambers capable of generating fluidic microvortices to rotate suspended cells. We then compared several microfluidic chip designs experimentally in terms of: (1 their ability to rotate biological cells in a stable and precise manner; and (2 their suitability, from a geometric standpoint, for microscopic cell imaging. We selected a design that incorporates a trapezoidal side chamber connected to a main flow channel because it provided well-controlled circulation and met imaging requirements. Micro particle-image velocimetry (micro-PIV was used to provide a detailed characterization of flows in the new design. Simulated and experimental results demonstrate that a trapezoidal side chamber represents a viable option for accomplishing controlled single cell rotation. Further, agreement between experimental and simulated results confirms that numerical simulation is an effective method for chamber design.

  1. Modeling of Experimental Adsorption Isotherm Data

    Directory of Open Access Journals (Sweden)

    Xunjun Chen

    2015-01-01

    Full Text Available Adsorption is considered to be one of the most effective technologies widely used in global environmental protection areas. Modeling of experimental adsorption isotherm data is an essential way for predicting the mechanisms of adsorption, which will lead to an improvement in the area of adsorption science. In this paper, we employed three isotherm models, namely: Langmuir, Freundlich, and Dubinin-Radushkevich to correlate four sets of experimental adsorption isotherm data, which were obtained by batch tests in lab. The linearized and non-linearized isotherm models were compared and discussed. In order to determine the best fit isotherm model, the correlation coefficient (r2 and standard errors (S.E. for each parameter were used to evaluate the data. The modeling results showed that non-linear Langmuir model could fit the data better than others, with relatively higher r2 values and smaller S.E. The linear Langmuir model had the highest value of r2, however, the maximum adsorption capacities estimated from linear Langmuir model were deviated from the experimental data.

  2. Multifragment emission and the experimental characterization of breakup reactions

    International Nuclear Information System (INIS)

    Martinez Heimann, D.; Pacheco, A. J.; Arazi, A.; Fernandez Niello, J. O.; Figueira, J. M.; Negri, A.; Capurro, O. A.; Carnelli, P.; Cardona, M. A.; Barbara, E. de; Fimiani, L.; Hojman, D. L.; Marti, G. V.

    2010-01-01

    The production of three or more particles in nuclear reactions is discussed in terms of physically meaningful variables for the description of the asymptotic exit-channel configuration. The emphasis is placed in a direct comparison between these basic variables obtained in a purely experimental way and the corresponding results of generic model calculations. Applications of this approach to a few examples of recent inclusive and exclusive measurements of breakup reactions in the 6,7 Li+ 144 Sm systems are presented.

  3. Hemorrhoids: an experimental model in monkeys

    Directory of Open Access Journals (Sweden)

    Plapler Hélio

    2006-01-01

    Full Text Available PURPOSE: Hemorrhoids are a matter of concern due to a painful outcome. We describe a simple, easy and reliable experimental model to produce hemorrhoids in monkeys. METHODS: 14 monkeys (Cebus apella were used. After general anesthesia, hemorrhoids were induced by ligation of the inferior hemorrhoidal vein, which is very alike to humans. The vein was located through a perianal incision, dissected and ligated with a 3-0 vicryl. The skin was sutured with a 4-0 catgut thread. Animals were kept in appropriate cages and evaluated daily. RESULTS: Nine days later there were hemorrhoidal piles in the anus in fifty percent (50% of the animals. Outcome was unremarkable. There was no bleeding and all animals showed no signs of pain or suffering. CONCLUSION: This is an affordable and reliable experimental model to induce hemorrhoids for experimental studies.

  4. Optimal Experimental Design for Model Discrimination

    Science.gov (United States)

    Myung, Jay I.; Pitt, Mark A.

    2009-01-01

    Models of a psychological process can be difficult to discriminate experimentally because it is not easy to determine the values of the critical design variables (e.g., presentation schedule, stimulus structure) that will be most informative in differentiating them. Recent developments in sampling-based search methods in statistics make it…

  5. Experimental Characterization of Cryogenic Helium Pulsating Heat Pipes

    Science.gov (United States)

    Fonseca Flores, Luis Diego

    This study was inspired to investigate an alternative cooling system using a helium-based pulsating heat pipes (PHP), for low temperature superconducting magnets in MRI systems. In addition, the same approach can be used for exploring other low temperature applications such as cooling space instrumentation. The advantages of PHP for transferring heat and smoothing temperature profiles in various room temperature applications have been explored for the past 20 years. An experimental apparatus has been designed, fabricated and operated and is primarily composed of an evaporator and a condenser; in which both are thermally connected by a closed loop capillary tubing. The main goal is to measure the heat transfer properties of this device using helium as the working fluid. The evaporator end of the PHP is comprised of a copper winding in which heat loads up to 10 watts are generated, while the condenser is isothermal and can reach 4.2 K at 1 W via a two stage Sumitomo RDK408A2 GM cryocooler. Various experimental design features are highlighted. Additionally, the thermal performance for the presented design remained unchanged when increasing the adiabatic length from 300 mm to 1000 mm. Finally a spring mass damper model has been developed and proven to predict well the experimental data, such models should be used as tool to design and manufacturer PHP prototypes.

  6. Experimental characterization of Raman overlaps between mode-groups

    DEFF Research Database (Denmark)

    Christensen, Erik Nicolai; Koefoed, Jacob Gade; Friis, Søren Michael Mørk

    2016-01-01

    Mode-division multiplexing has the potential to further increase data transmission capacity through optical fibers. In addition, distributed Raman amplification is a promising candidate for multi-mode signal amplification due to its desirable noise properties and the possibility of mode-equalized......Mode-division multiplexing has the potential to further increase data transmission capacity through optical fibers. In addition, distributed Raman amplification is a promising candidate for multi-mode signal amplification due to its desirable noise properties and the possibility of mode......-equalized gain. In this paper, we present an experimental characterization of the intermodal Raman intensity overlaps of a few-mode fiber using backward-pumped Raman amplification. By varying the input pump power and the degree of higher order mode-excitation for the pump and the signal in a 10km long two......-mode fiber, we are able to characterize all intermodal Raman intensity overlaps. Using these results, we perform a Raman amplification measurement and demonstrate a mode-differential gain of only 0.25dB per 10dB overall gain. This is, to the best of our knowledge, the lowest mode differential gain achieved...

  7. Macrophages and Uveitis in Experimental Animal Models

    Directory of Open Access Journals (Sweden)

    Salvador Mérida

    2015-01-01

    Full Text Available Resident and infiltrated macrophages play relevant roles in uveitis as effectors of innate immunity and inductors of acquired immunity. They are major effectors of tissue damage in uveitis and are also considered to be potent antigen-presenting cells. In the last few years, experimental animal models of uveitis have enabled us to enhance our understanding of the leading role of macrophages in eye inflammation processes, including macrophage polarization in experimental autoimmune uveoretinitis and the major role of Toll-like receptor 4 in endotoxin-induced uveitis. This improved knowledge should guide advantageous iterative research to establish mechanisms and possible therapeutic targets for human uveitis resolution.

  8. Electrochemical desalination of bricks - Experimental and modeling

    DEFF Research Database (Denmark)

    Skibsted, Gry; Ottosen, Lisbeth M.; Jensen, Pernille Erland

    2015-01-01

    Chlorides, nitrates and sulfates play an important role in the salt-decay of porous materials in buildings and monuments. Electrochemical desalination is a technology able to remove salts from such porous materials in order to stop or prevent the decay. In this paper, experimental and numerical......-contaminated bricks with respect to the monovalent ions is discussed. Comparison between the experimental and the simulation results showed that the proposed numerical model is able to predict electrochemical desalination treatments with remarkable accuracy, and it can be used as a predictive tool...

  9. Characterizing and modeling citation dynamics.

    Directory of Open Access Journals (Sweden)

    Young-Ho Eom

    Full Text Available Citation distributions are crucial for the analysis and modeling of the activity of scientists. We investigated bibliometric data of papers published in journals of the American Physical Society, searching for the type of function which best describes the observed citation distributions. We used the goodness of fit with Kolmogorov-Smirnov statistics for three classes of functions: log-normal, simple power law and shifted power law. The shifted power law turns out to be the most reliable hypothesis for all citation networks we derived, which correspond to different time spans. We find that citation dynamics is characterized by bursts, usually occurring within a few years since publication of a paper, and the burst size spans several orders of magnitude. We also investigated the microscopic mechanisms for the evolution of citation networks, by proposing a linear preferential attachment with time dependent initial attractiveness. The model successfully reproduces the empirical citation distributions and accounts for the presence of citation bursts as well.

  10. Irradiation Design for an Experimental Murine Model

    International Nuclear Information System (INIS)

    Ballesteros-Zebadua, P.; Moreno-Jimenez, S.; Suarez-Campos, J. E.; Celis, M. A.; Larraga-Gutierrez, J. M.; Garcia-Garduno, O. A.; Rubio-Osornio, M. C.; Custodio-Ramirez, V.; Paz, C.

    2010-01-01

    In radiotherapy and stereotactic radiosurgery, small animal experimental models are frequently used, since there are still a lot of unsolved questions about the biological and biochemical effects of ionizing radiation. This work presents a method for small-animal brain radiotherapy compatible with a dedicated 6MV Linac. This rodent model is focused on the research of the inflammatory effects produced by ionizing radiation in the brain. In this work comparisons between Pencil Beam and Monte Carlo techniques, were used in order to evaluate accuracy of the calculated dose using a commercial planning system. Challenges in this murine model are discussed.

  11. Experimental characterization of vertical-axis wind turbine noise.

    Science.gov (United States)

    Pearson, C E; Graham, W R

    2015-01-01

    Vertical-axis wind turbines are wind-energy generators suitable for use in urban environments. Their associated noise thus needs to be characterized and understood. As a first step, this work investigates the relative importance of harmonic and broadband contributions via model-scale wind-tunnel experiments. Cross-spectra from a pair of flush-mounted wall microphones exhibit both components, but further analysis shows that the broadband dominates at frequencies corresponding to the audible range in full-scale operation. This observation has detrimental implications for noise-prediction reliability and hence also for acoustic design optimization.

  12. Characterization of an erbium doped fiber amplifier starting from its experimental parameters

    International Nuclear Information System (INIS)

    Bello J, M.; Kuzin, E.A.; Ibarra E, B.; Tellez G, R.

    2007-01-01

    In this paper we describe a method to characterize the gain of an erbium-doped fiber amplifier (EDFA) through the numerical simulation of the signal beam along the amplifier. The simulation is based on a model constituted by the propagation and rate equations for an erbium-doped fiber. The manipulation of these equations allows us to regroup the parameters present in an EDFA, which we have named the A, B, C, D parameters, and they can be obtained experimentally from an erbium-doped fiber. Experimental results show that the measurement of these parameters allow us to estimate with very good correspondence the amplifier gain. (Author)

  13. Huntington disease: Experimental models and therapeutic perspectives

    International Nuclear Information System (INIS)

    Serrano Sanchez, Teresa; Blanco Lezcano, Lisette; Garcia Minet, Rocio; Alberti Amador, Esteban; Diaz Armesto, Ivan and others

    2011-01-01

    Huntington's disease (HD) is a degenerative dysfunction of hereditary origin. Up to date there is not, an effective treatment to the disease which having lapsed 15 or 20 years advances inexorably, in a slow form, toward the total inability or death. This paper reviews the clinical and morphological characteristics of Huntington's disease as well as the experimental models more commonly used to study this disease, having as source the articles indexed in Medline data base, published in the last 20 years. Advantages and disadvantages of all experimental models to reproduce the disease as well as the perspectives to therapeutic assay have been also considered. the consent of outline reported about the toxic models, those induced by neurotoxins such as quinolinic acid, appears to be the most appropriate to reproduce the neuropathologic characteristic of the disease, an genetic models contributing with more evidence to the knowledge of the disease etiology. Numerous treatments ameliorate clinical manifestations, but none of them has been able to stop or diminish the affectations derived from neuronal loss. At present time it is possible to reproduce, at least partially, the characteristics of the disease in experimentation animals that allow therapy evaluation in HD. from the treatment view point, the more promissory seems to be transplantation of no neuronal cells, taking into account ethical issues and factibility. On the other hand the new technology of interference RNA emerges as a potential therapeutic tool for treatment in HD, and to respond basic questions on the development of the disease.

  14. An experimental method of characterization of deformable porous media

    Directory of Open Access Journals (Sweden)

    Sommier Alain

    2012-04-01

    Full Text Available A porous medium saturated with liquid and placed within a medium that undergoes a change in pressure reacts by shrinking. If the space contains the same liquid as the pores of the sample, then after a certain lapse of time the sample dilates. By measuring this dilation kinetic the specimen’s permeability can be approximated. This experimental method is called Dynamic Pressurisation. We set up an experimental apparatus to measure the permeability and the different agarose gel compressibility moduli. The liquid contained inside the gel pores is water. We have realized experiments in water and others in oil. In Scherer’s method the flow is considered only in the radial direction. To find the real permeability value we have built a numerical model considering that both the liquid and the solid are compressible. The simulations were compared to the experimental results and have allowed finding the real value of the permeability by considering the flow in both radial and axial directions.

  15. Experimental alveolitis in rats: microbiological, acute phase response and histometric characterization of delayed alveolar healing.

    Science.gov (United States)

    Rodrigues, Moacyr Tadeu Vicente; Cardoso, Camila Lopes; Carvalho, Paulo Sérgio Perri de; Cestari, Tânia Mary; Feres, Magda; Garlet, Gustavo Pompermaier; Ferreira, Osny

    2011-01-01

    The pathogenesis of alveolitis is not well known and therefore experimental situations that mimic some features of this disease should be developed. In this study, the evolution of the experimentally induced infection in rat sockets is characterized, which leads to clinical signs of suppurative alveolitis with remarkable wound healing disturbs. Non-infected (Group I) and experimentally infected sockets in Rattus novergicus (Group II) were histometrically evaluated regarding the kinetics of alveolar healing. In addition, the characterization of the present bacteria in inoculation material and the serum levels of C-reactive protein (CRP) were performed. The detected species were Capnocytophaga ochracea, Fusobacterium nucleatum ss nucleatum, Prevotella melaninogenica, Streptococcus anginosus, Treponema socranskii and Streptococcus sanguis. All experimentally infected rats developed suppurative alveolitis, showing higher levels of CRP in comparison to those non-infected ones. Furthermore, infected rats presented a significant delayed wound healing as measured by the histometric analysis (higher persistent polymorphonuclear infiltrate and lower density of newly formed bone). These findings indicate that rat sockets with experimentally induced infection produced higher levels of serum CRP, showing the potential of disseminated infection and a disturb in the alveolar repair process in an interesting experimental model for alveolitis studies.

  16. Adjustment model of thermoluminescence experimental data

    International Nuclear Information System (INIS)

    Moreno y Moreno, A.; Moreno B, A.

    2002-01-01

    This model adjusts the experimental results for thermoluminescence according to the equation: I (T) = I (a i * exp (-1/b i * (T-C i )) where: a i , b i , c i are the i-Th peak adjusted to a gaussian curve. The adjustments of the curve can be operated manual or analytically using the macro function and the solver.xla complement installed previously in the computational system. In this work it is shown: 1. The information of experimental data from a LiF curve obtained from the Physics Institute of UNAM which the data adjustment model is operated in the macro type. 2. A LiF curve of four peaks obtained from Harshaw information simulated in Microsoft Excel, discussed in previous works, as a reference not in macro. (Author)

  17. Experimental characterization of resistive joints for use inside ATLAS toroids

    CERN Document Server

    Volpini, G; Pojer, M

    2001-01-01

    The authors have investigated, both experimentally and theoretically, the thermo-electrical behavior of the ATLAS magnets resistive joints. These magnets exploit an Al-clad NbTi Rutherford superconducting cable, and the splices between different sections are performed by TIG-welding the Al matrices of the two cables to be connected. This technique is simple from a construction point of view, and we have shown that its performance is adequate for a safe operation of the magnets. The two main concerns during the design of these joints are the temperature rise due to Joule dissipation and the eddy currents induced under nonstationary conditions. We have devised a reliable model of these joints, that allows estimating their resistances and the induced eddy currents; later we have built and measured several sample joints to give experimental confirmation. The model requires, along with the joint geometry, the knowledge of the Rutherford-matrix interface resistance as well as the RRR of the aluminum matrix. In this...

  18. Experimental tests of proton spin models

    International Nuclear Information System (INIS)

    Ramsey, G.P.; Argonne National Lab., IL

    1989-01-01

    We have developed models for the spin-weighted quark and gluon distribution in a longitudinally polarized proton. The model parameters are determined from current algebra sum rules and polarized deep-inelastic scattering data. A number of different scenarios are presented for the fraction of spin carried the constituent parton distributions. A possible long-range experimental program is suggested for measuring various hard scattering processes using polarized lepton and proton beams. With the knowledge gained from these experiments, we can begin to understand the parton contributions to the proton spin. 28 refs., 5 figs

  19. Experimental In Vivo Models of Candidiasis

    Directory of Open Access Journals (Sweden)

    Esther Segal

    2018-02-01

    Full Text Available Candidiasis is a multifaceted fungal disease including mucosal-cutaneous, visceral, and disseminated infections caused by yeast species of the genus Candida. Candida infections are among the most common human mycoses. Candida species are the third to fourth most common isolates from bloodstream infections in neutropenic or immunocompromised hospitalized patients. The mucosal-cutaneous forms—particularly vaginal infections—have a high prevalence. Vaginitis caused by Candida species is the second most common vaginal infection. Hence, candidiasis is a major subject for research, including experimental in vivo models to study pathogenesis, prevention, or therapy of the disease. The following review article will focus on various experimental in vivo models in different laboratory animals, such as mammals (mice, rats, rabbits, the fruit fly–Drosophila melanogaster, the larvae of the moth Galleria mellonella, or the free-living nematode Caenorhabditis elegans. The review will describe the induction of the different clinical forms of candidiasis in the various models and the validity of such models in mimicking the human clinical situations. The use of such models for the assessment of antifungal drugs, evaluation of potential vaccines to protect before candidiasis, exploration of Candida virulence factors, and comparison of pathogenicity of different Candida species will be included in the review. All of the above will be reported as based on published studies of numerous investigators as well as on the research of the author and his group.

  20. Characterization of the Chicken Ovarian Cancer Model

    National Research Council Canada - National Science Library

    Rodriguez, Gustavo

    2002-01-01

    .... Unlike other ovarian cancer models, which require experimental induction of ovarian tumors, chickens develop ovarian adenocarcinoma spontaneously, with an incidence ranging from 13 to 40 percent...

  1. Characterization of the Chicken Ovarian Cancer Model

    National Research Council Canada - National Science Library

    Rodriguez, Gustavo C

    2004-01-01

    .... Unlike other ovarian cancer models, which require experimental induction of ovarian tumors, chickens develop ovarian adenocarcinoma spontaneously, with an incidence ranging from 13 to 40 percent...

  2. Characterization of the Chicken Ovarian Cancer Model

    National Research Council Canada - National Science Library

    Rodriguez, Gustavo C

    2005-01-01

    .... Unlike other ovarian cancer models, which require experimental induction of ovarian tumors, chickens develop ovarian adenocarcinoma spontaneously, with an incidence ranging from 13 to 40 percent...

  3. Characterization of the Chicken Ovarian Cancer Model

    National Research Council Canada - National Science Library

    Rodriguez, Gustavo

    2003-01-01

    .... Unlike other ovarian cancer models, which require experimental induction of ovarian tumors, chickens develop ovarian adenocarcinoma spontaneously, with an incidence ranging from 13 to 40 percent...

  4. Characterization of the Chicken Ovarian Cancer Model

    National Research Council Canada - National Science Library

    Rodriquez, Gustavo

    2001-01-01

    .... Unlike other ovarian cancer models, which require experimental induction of ovarian tumors, chickens develop ovarian adenocarcinoma spontaneously, with an incidence ranging from 13 to 40 percent...

  5. Endometriose: modelo experimental em ratas Endometriosis: experimental model in rats

    Directory of Open Access Journals (Sweden)

    Eduardo Schor

    1999-06-01

    Full Text Available Objetivo: divulgar a metodologia da indução de endometriose experimental em animais de laboratório. Método: utilizamos ratas albinas, virgens, adultas de aproximadamente três meses de idade, que foram inicialmente anestesiadas pelo éter etílico. Aberta a cavidade abdominal, identificamos os cornos uterinos e retiramos um fragmento de aproximadamente 4 cm do corno uterino direito. Esse fragmento foi mergulhado em solução fisiológica e sob lupa estereoscópica foi separado o endométrio do miométrio e feitos retângulos de aproximadamente 4 por 5 mm. Esses foram fixados por meio de fio de sutura, sobre vasos sangüíneos visíveis a olho nu, na parede lateral do abdômen, tomando-se sempre o cuidado de manter a porção do endométrio livre voltada para a luz da cavidade abdominal. Após 21 dias os animais foram novamente operados para verificarmos o tamanho dos implantes e para retirada do endométrio ectópico para análise histológica. Resultados: macroscopicamente observamos crescimento significativo dos implantes endometriais. Ao exame microscópico pudemos observar a presença de epitélio glandular e estroma semelhantes ao do endométrio tópico. Conclusões: o modelo utilizado reproduz a doença, em ratas, sendo método auxiliar de valia para estudar esta afecção, principalmente a ação de medicamentos sobre esses implantes.Purpose: to demonstrate the experimental endometriosis induction in animals. Method: we used adult female Wistar rats weighing 200 - 250 g anesthetized with ethyl ether to open the abdominal cavity. After identifying the uterine horns, we removed an approximately 4 cm fragment from the right uterine horn. This fragment was placed in physiological saline and, with the aid of a stereoscopic magnifying glass, the endometrium was separated from the myometrium and cut into rectangles of approximately 4 x 5 mm. These rectangles were fastened to the lateral abdominal wall near great blood vessels, taking care

  6. Characterization of nanotransistors in a semiempirical model

    Energy Technology Data Exchange (ETDEWEB)

    Wulf, U., E-mail: ulrich.wulf@b-tu.de [Brandenburg Technical University, POB 101344, 03013 Cottbus (Germany); Kučera, J. [Institute of Physics, Academy of Sciences of the Czech Republic, Cukrovanická 10, 162 53, Praha 6 (Czech Republic); Richter, H. [Brandenburg Technical University, POB 101344, 03013 Cottbus (Germany); GFWW, Im Technologiepark 1, 15236 Frankfurt (Oder) (Germany); Wiatr, M.; Höntschel, J. [GLOBALFOUNDRIES Dresden, Wilschdorfer Landstraße 101, 01109 Dresden (Germany)

    2016-08-31

    In a series of recent papers we have established a semiempirical model for quantum transport in a nanotransistor. Here we apply this model to characterize four industrial transistors with gate lengths ranging between 22 nm and 30 nm finding excellent quantitative agreement between theory and experiment. Adjusting our semiempirical model to the experimental output traces, three calibration parameters are found: First, the height of the source–drain barrier, second, the device temperature, and, third, the overlap parameter. The overlap parameter describes the wave function overlap between the source/drain contact and the conduction channel. With the aid of the calibration parameters the considered devices can be classified in three groups: A first group (G1) with good contact-channel coupling and a high saturation current, a second group (G2) with intermediate values and a third group (G3) with poor contact-channel coupling and a small saturation current. We calculate the gate capacitance of the transistors: At threshold voltage a peak of the gate capacitance is observed which is associated with a jump in the overlap parameter. This finding is most pronounced in G1, weaker in G2 and absent in G3. We attribute it to favorable screening conditions in G1 leading to a smooth transition between the contacts and the conduction channel. Our results indicate that this screening effect is favored by an efficient release of the Ohmic heat. - Highlights: • Semiempirical model for nano-scale field effect transistors • Quantitative description of seven experimental I-V-traces • Contact-channel coupling in transistor and peak in gate capacitance • Screening in the conduction channel of a nanoFET.

  7. Pneumatic Adaptive Absorber: Mathematical Modelling with Experimental Verification

    Directory of Open Access Journals (Sweden)

    Grzegorz Mikułowski

    2016-01-01

    Full Text Available Many of mechanical energy absorbers utilized in engineering structures are hydraulic dampers, since they are simple and highly efficient and have favourable volume to load capacity ratio. However, there exist fields of applications where a threat of toxic contamination with the hydraulic fluid contents must be avoided, for example, food or pharmacy industries. A solution here can be a Pneumatic Adaptive Absorber (PAA, which is characterized by a high dissipation efficiency and an inactive medium. In order to properly analyse the characteristics of a PAA, an adequate mathematical model is required. This paper proposes a concept for mathematical modelling of a PAA with experimental verification. The PAA is considered as a piston-cylinder device with a controllable valve incorporated inside the piston. The objective of this paper is to describe a thermodynamic model of a double chamber cylinder with gas migration between the inner volumes of the device. The specific situation considered here is that the process cannot be defined as polytropic, characterized by constant in time thermodynamic coefficients. Instead, the coefficients of the proposed model are updated during the analysis. The results of the experimental research reveal that the proposed mathematical model is able to accurately reflect the physical behaviour of the fabricated demonstrator of the shock absorber.

  8. Canine C-peptide for characterization of experimental diabetes in dogs

    International Nuclear Information System (INIS)

    Fischer, U.; Besch, W.; Freyse, E.-J.

    1985-01-01

    Radioimmunoassay of canine C-peptide (CCP) was developed for the characterization of endogenous beta cell function in experimentally diabetic dogs. The animals were rendered diabetic by subtotal pancreatectomy and intrasurgical infusion of 2 mg/kg streptozotocin into the superior pancreaticoduodenal artery. After an average duration of diabetes of 5 months the animals showed zero peripheral venous fasting CCP levels with no response to feeding, OGTT/i.v. glucagon loading or i.v. glucose tolerance testing. The data on CCP levels entirely coincided with simultaneously measured plasma IRI levels. In non-diabetic control animals clear-cut CCP increases were observed after all stimuli. The experimental model provided an IDDM-type diabetes without toxic symptoms but with a sufficient exocrine pancreatic function. The comparison showed that plasma IRI analyses would also allow reliable characterization of insulinogenic functions in these animals. (author)

  9. Experimental animal modelling for TB vaccine development

    Directory of Open Access Journals (Sweden)

    Pere-Joan Cardona

    2017-03-01

    Full Text Available Research for a novel vaccine to prevent tuberculosis is an urgent medical need. The current vaccine, BCG, has demonstrated a non-homogenous efficacy in humans, but still is the gold standard to be improved upon. In general, the main indicator for testing the potency of new candidates in animal models is the reduction of the bacillary load in the lungs at the acute phase of the infection. Usually, this reduction is similar to that induced by BCG, although in some cases a weak but significant improvement can be detected, but none of candidates are able to prevent establishment of infection. The main characteristics of several laboratory animals are reviewed, reflecting that none are able to simulate the whole characteristics of human tuberculosis. As, so far, no surrogate of protection has been found, it is important to test new candidates in several models in order to generate convincing evidence of efficacy that might be better than that of BCG in humans. It is also important to investigate the use of “in silico” and “ex vivo” models to better understand experimental data and also to try to replace, or at least reduce and refine experimental models in animals.

  10. Models for Experimental High Density Housing

    Science.gov (United States)

    Bradecki, Tomasz; Swoboda, Julia; Nowak, Katarzyna; Dziechciarz, Klaudia

    2017-10-01

    The article presents the effects of research on models of high density housing. The authors present urban projects for experimental high density housing estates. The design was based on research performed on 38 examples of similar housing in Poland that have been built after 2003. Some of the case studies show extreme density and that inspired the researchers to test individual virtual solutions that would answer the question: How far can we push the limits? The experimental housing projects show strengths and weaknesses of design driven only by such indexes as FAR (floor attenuation ratio - housing density) and DPH (dwellings per hectare). Although such projects are implemented, the authors believe that there are reasons for limits since high index values may be in contradiction to the optimum character of housing environment. Virtual models on virtual plots presented by the authors were oriented toward maximising the DPH index and DAI (dwellings area index) which is very often the main driver for developers. The authors also raise the question of sustainability of such solutions. The research was carried out in the URBAN model research group (Gliwice, Poland) that consists of academic researchers and architecture students. The models reflect architectural and urban regulations that are valid in Poland. Conclusions might be helpful for urban planners, urban designers, developers, architects and architecture students.

  11. Experimental data and dose-response models

    International Nuclear Information System (INIS)

    Ullrich, R.L.

    1985-01-01

    Dose-response relationships for radiation carcinogenesis have been of interest to biologists, modelers, and statisticians for many years. Despite his interest there are few instances in which there are sufficient experimental data to allow the fitting of various dose-response models. In those experimental systems for which data are available the dose-response curves for tumor induction for the various systems cannot be described by a single model. Dose-response models which have been observed following acute exposures to gamma rays include threshold, quadratic, and linear models. Data on sex, age, and environmental influences of dose suggest a strong role of host factors on the dose response. With decreasing dose rate the effectiveness of gamma ray irradiation tends to decrease in essentially every instance. In those cases in which the high dose rate dose response could be described by a quadratic model, the effect of dose rate is consistent with predictions based on radiation effects on the induction of initial events. Whether the underlying reasons for the observed dose-rate effect is a result of effects on the induction of initial events or is due to effects on the subsequent steps in the carcinogenic process is unknown. Information on the dose response for tumor induction for high LET (linear energy transfer) radiations such as neutrons is even more limited. The observed dose and dose rate data for tumor induction following neutron exposure are complex and do not appear to be consistent with predictions based on models for the induction of initial events

  12. Experimental Flow Characterization of a Flow Diverting Device

    Science.gov (United States)

    Sparrow, Eph; Chow, Ricky; Campbell, Gary; Divani, Afshin; Sheng, Jian

    2012-11-01

    Flow diverters, such as the Pipeline Embolization Device, are a new class of endovascular devices for the treatment of intracranial aneurysms. While clinical studies have demonstrated safety and efficacy, their impact on intra-aneurysmal flow is not confirmed experimentally. As such, optimization of the flow diversion behavior is not currently possible. A quasi-3D PIV technique was developed and applied in various glass models at Re = 275 and 550 to determine the changes to flow characteristics due to the deployment of a flow diverter across the aneurysm neck. Outcomes such as mean velocity, wall shear stress, and others metrics will be presented. Glass models with varying radii of curvature and aneurysm locations will be examined. Experiments were performed in a fully index-matched flow facility using ~10 μm diameter polystyrene particles doped with Rhodium 6G dye. The particles were illuminated with a 532nm laser sheet and observed with a CCD camera and a 592nm +/-43 nm bandpass filter. A quasi 3D flow field was reconstructed from multiple orthogonal planes (spaced 0.4mm apart) encompassing the entire glass model. Wall stresses were evaluated from the near-wall flow viscous stresses.

  13. Surface physics theoretical models and experimental methods

    CERN Document Server

    Mamonova, Marina V; Prudnikova, I A

    2016-01-01

    The demands of production, such as thin films in microelectronics, rely on consideration of factors influencing the interaction of dissimilar materials that make contact with their surfaces. Bond formation between surface layers of dissimilar condensed solids-termed adhesion-depends on the nature of the contacting bodies. Thus, it is necessary to determine the characteristics of adhesion interaction of different materials from both applied and fundamental perspectives of surface phenomena. Given the difficulty in obtaining reliable experimental values of the adhesion strength of coatings, the theoretical approach to determining adhesion characteristics becomes more important. Surface Physics: Theoretical Models and Experimental Methods presents straightforward and efficient approaches and methods developed by the authors that enable the calculation of surface and adhesion characteristics for a wide range of materials: metals, alloys, semiconductors, and complex compounds. The authors compare results from the ...

  14. Superficial tension: experimental model with simple materials

    Directory of Open Access Journals (Sweden)

    Tintori Ferreira, María Alejandra

    2012-09-01

    Full Text Available In this work appears a didactic offer based on an experimental activity using materials of very low cost, orientated to achieving that the student understand and interpret the phenomenon of superficial tension together with the importance of the modeling in sciences. It has as principal aim of education bring the student over to the mechanics of the static fluids and the intermolecular forces, combining scientific contents with questions near to the student what provides an additional motivation to the reflection of the scientific investigation.

  15. An experimental study of thermal characterization of parabolic trough receivers

    International Nuclear Information System (INIS)

    Lei, Dongqiang; Li, Qiang; Wang, Zhifeng; Li, Jian; Li, Jianbin

    2013-01-01

    Highlights: ► A new test stand of heat loss has been developed at IEECAS. ► A correlation between heat loss and absorber temperature is presented, 270 W/m 400 °C. ► The ratio of end loss in total heat loss increases with decreasing the temperature. ► The emittance test stand using a high vacuum system and vacuum gauge is built. ► Emittance first decreases, then rapidly increases with increasing the temperature. - Abstract: The receiver is a key component of the parabolic trough solar station. The receiver requires the most challenging technology and has a decisive influence on the thermal and economic performance of a power plant. The Institute of Electrical Engineering Chinese Academy Sciences (IEECAS) and Himin Solar Co., Ltd. (HSC) cooperated to develop solar receivers for the first 50 MW parabolic trough project in Inner Mongolia, China. This paper examines overall heat loss, end loss and thermal emittance of the coating of a newly designed receiver in order to evaluate its thermal characterization. A series of heat loss tests are conducted in a newly developed test stand following the steady state equilibrium method. The tests provide a correlation between heat loss and the absorber temperature. This paper presents a new testing method to accurately test the coating emittance. The method uses a receiver with a high vacuum system and a vacuum gauge to maintain continuous exhaust and high vacuum throughout the heat loss testing. A heat loss comparison between the receiver and other existing receivers provides a reference that enabled further optimization. Theoretical and experimental analysis examines the effects of end loss both with and without a heat insulator and a coil heater. The emittance curves of different coatings are acquired and the reasons for initial emittance decrease and then remarkable increase versus temperature are analyzed

  16. Experimental Characterization of Radiation Forcing due to Atmospheric Aerosols

    Science.gov (United States)

    Sreenivas, K. R.; Singh, D. K.; Ponnulakshmi, V. K.; Subramanian, G.

    2011-11-01

    Micro-meteorological processes in the nocturnal atmospheric boundary layer (NBL) including the formation of radiation-fog and the development of inversion layers are controlled by heat transfer and the vertical temperature distribution close to the ground. In a recent study, it has been shown that the temperature profile close to the ground in stably-stratified, NBL is controlled by the radiative forcing due to suspended aerosols. Estimating aerosol forcing is also important in geo-engineering applications to evaluate the use of aerosols to mitigate greenhouse effects. Modeling capability in the above scenarios is limited by our knowledge of this forcing. Here, the design of an experimental setup is presented which can be used for evaluating the IR-radiation forcing on aerosols under either Rayleigh-Benard condition or under conditions corresponding to the NBL. We present results indicating the effect of surface emissivities of the top and bottom boundaries and the aerosol concentration on the temperature profiles. In order to understand the observed enhancement of the convection-threshold, we have determined the conduction-radiation time constant of an aerosol laden air layer. Our results help to explain observed temperature profiles in the NBL, the apparent stability of such profiles and indicate the need to account for the effect of aerosols in climatic/weather models.

  17. Experimental model of bladder instability in rabbits

    Directory of Open Access Journals (Sweden)

    Balasteghin K.T.

    2003-01-01

    Full Text Available OBJECTIVE: Propose a new experimental model of bladder instability in rabbits after partial bladder obstruction. MATERIALS AND METHODS: Thirty North Folk male rabbits, weighting 1,700 to 2,820 g (mean: 2,162 g were studied. The animals were distributed in 2 experimental groups, formed by 15 rabbits each: Group 1 - clinical control. In this group there was no surgical intervention; Group 2 - bladder outlet obstruction. In this group, after anesthetizing the animal, urethral cannulation with Foley catheter 10F was performed and then an adjustable plastic bracelet was passed around the bladder neck. It was then adjusted in order to not constrict the urethra. The following parameters were studied in M1 - pre-operative period; M2 - 4 weeks post-operatively moments: 1- urine culture; 2- cystometric study; 3- serum creatinine and BUN. RESULTS: Bladder weight was 2.5 times larger in the group with obstruction than in the control group. Cystometric evaluation showed a significant increase in maximal vesical volume in the final moment at Group G2. However, there was no statistically significant difference among the groups studied. There was no statistically significant difference between maximal detrusor pressure and vesical compliance in the different moments or in the studied groups. There was an absence of uninhibited detrusor contractions in all the animals in group 1, and involuntary contractions were detected in 93% of group 2 animals. There was no significant variation in BUN and serum creatinine either among the groups or in the same group. CONCLUSIONS: We observed in the group with obstruction a bladder weight 2.5 higher than normal bladders. We detected involuntary contractions in 93% of the animals in group 2, establishing this experimental model as appropriate to secondary bladder instability and partial bladder outlet obstruction.

  18. Experimental models of chronic subdural hematoma.

    Science.gov (United States)

    D'Abbondanza, Josephine A; Loch Macdonald, R

    2014-02-01

    Chronic subdural hematoma (CSDH) is a common neurosurgical problem. Most studies of pathogenesis and treatment involve humans. Advances in understanding of human diseases may be made using animal models. We reviewed all animal models of CSDH and report here their results, conclusions and limitations in order to set a baseline upon which further advanced experimental work related to this disease can be made. PubMed, Medline, Embase and ISI Web of Knowledge were searched with no time limits using the keyword 'chronic subdural hematoma' and MeSH term 'hematoma, subdural, chronic'. The authors reviewed all papers written related to this disease and selected all publications involving animals. There were no other restrictions. The findings and conclusions of the papers are summarized here. No formal analysis was done because of the variation in species used, methods for induction of CSDH, times of assessment and reporting of results. Attempts to create CSDH have been made in mice, rats, cats, dogs and monkeys. Methods include injection or surgical implantation of clotted blood or various other blood products and mixtures into the potential subdural space or the subcutaneous space. No intracranial model produced a progressively expanding CSDH. Transient hematoma expansion with liquification could be produced by subcutaneous injections in some models. Spontaneous subdural blood collections were found after creation of hydrocephalus in mice by systemic injection of the neurotoxin, 6-aminonicotinamide. The histology of the hematoma membranes in several models resembles the appearance in humans. None of the models has been replicated since its first description. We did not find a report of a reproducible, well-described animal model of human CSDH.

  19. Experimental characterization of Fresnel-Köhler concentrators

    Science.gov (United States)

    Zamora, Pablo; Benítez, Pablo; Mohedano, Rubén; Cvetković, Aleksandra; Vilaplana, Juan; Li, Yang; Hernández, Maikel; Chaves, Julio; Miñano, Juan C.

    2012-01-01

    Most cost-effective concentrated photovoltaics (CPV) systems are based on an optical train comprising two stages, the first being a Fresnel lens. Among them, the Fresnel-Köhler (FK) concentrator stands out owing to both performance and practical reasons. We describe the experimental measurements procedure for FK concentrator modules. This procedure includes three main types of measurements: electrical efficiency, acceptance angle, and irradiance uniformity at the solar cell plane. We have collected here the performance features of two different FK prototypes (ranging different f-numbers, concentration ratios, and cell sizes). The electrical efficiencies measured in both prototypes are high and fit well with the models, achieving values up to 32.7% (temperature corrected, and with no antireflective coating on SOE or POE surfaces) in the best case. The measured angular transmission curves show large acceptance angles, again perfectly matching the expected values [measured concentration acceptance product (CAP) values over 0.56]. The irradiance pattern on the cell (obtained with a digital camera) shows an almost perfectly uniform distribution, as predicted by raytrace simulations. All these excellent on-sun results confirm the FK concentrator as a potentially cost-effective solution for the CPV market.

  20. Experimental and theoretical requirements for fuel modelling

    International Nuclear Information System (INIS)

    Gatesoupe, J.P.

    1979-01-01

    From a scientific point of view it may be considered that any event in the life of a fuel pin under irradiation should be perfectly well understood and foreseen from that deterministic point of view, the whole behaviour of the pin maybe analysed and dismantled with a specific function for every component part and each component part related to one basic phenomenon which can be independently studied on pure physical grounds. When extracted from the code structure the subroutine is studied for itself by specialists who try to keep as close as possible to the physics involved in the phenomenon; that often leads to an impressive luxury in details and a subsequent need for many unavailable input data. It might seem more secure to follow that approach since it tries to be firmly based on theoretical grounds. One should think so if the phenomenological situation in the pin were less complex than it is. The codes would not be adequate for off-normal operating conditions since for the accidental transient conditions the key-phenomena would not be the same as for steady-state or slow transient conditions. The orientation given to fuel modelling is based on our two main technological constraints which are: no fuel melting; no cladding failure; no excessive cladding deformation. In this context, the only relevant models are those which have a significant influence on the maximum temperatures in the fuel or on the cladding damage hence the selection between key models and irrelevant models which will next be done. A rather pragmatic view is kept on codification with a special focus on a few determinant aspects of fuel behaviour and no attention to models which are nothing but decorative. Fuel modeling is merely considered as a link between experimental knowledge; it serves as a guide for further improvements in fuel design and as so happens to be quite useful. On this basis the main lacks in of fuel behaviour is described. These are mainly concerning: thermal transfer through

  1. Experimental study and modelling of transient boiling

    International Nuclear Information System (INIS)

    Baudin, Nicolas

    2015-01-01

    A failure in the control system of the power of a nuclear reactor can lead to a Reactivity Initiated Accident in a nuclear power plant. Then, a power peak occurs in some fuel rods, high enough to lead to the coolant film boiling. It leads to an important increase of the temperature of the rod. The possible risk of the clad failure is a matter of interest for the Institut de Radioprotection et de Securite Nucleaire. The transient boiling heat transfer is not yet understood and modelled. An experimental set-up has been built at the Institut de Mecanique des Fluides de Toulouse (IMFT). Subcooled HFE-7000 flows vertically upward in a semi annulus test section. The inner half cylinder simulates the clad and is made of a stainless steel foil, heated by Joule effect. Its temperature is measured by an infrared camera, coupled with a high speed camera for the visualization of the flow topology. The whole boiling curve is studied in steady state and transient regimes: convection, onset of boiling, nucleate boiling, critical heat flux, film boiling and rewetting. The steady state heat transfers are well modelled by literature correlations. Models are suggested for the transient heat flux: the convection and nucleate boiling evolutions are self-similar during a power step. This observation allows to model more complex evolutions, as temperature ramps. The transient Hsu model well represents the onset of nucleate boiling. When the intensity of the power step increases, the film boiling begins at the same temperature but with an increasing heat flux. For power ramps, the critical heat flux decreases while the corresponding temperature increases with the heating rate. When the wall is heated, the film boiling heat transfer is higher than in steady state but it is not understood. A two-fluid model well simulates the cooling film boiling and the rewetting. (author)

  2. Fatigue crack propagation: Probabilistic models and experimental evidence

    International Nuclear Information System (INIS)

    Lucia, A.C.; Jovanovic, A.

    1987-01-01

    The central aim of the LWR Primary Circuit Component Life Prediction Project, going on at JRC-Ispra, is to develop and check a 'procedure' (encompassing monitoring and inspection, data collection and analysis, prediction) allowing the quantitatives estimation of the accumulation of structural damage and of the residual lifetime. The ongoing activity matches theoretical development and experimentation, the latter being at present essentially based on a test-rig for room-temperature fatigue cycling of 1:5 scaled models of pressure vessels. During Phase I of fatigue testing of vessel R2, different pieces of information coming from material characterization, non-destructive inspection, continuous monitoring, stress analysis, have been merged and used to infere the future behaviour of the structure. The prediction of residual lifetime (cycles to failure), based on the outcomes of the ultrasonic continuous monitoring and made by means of the COVASTOL code, was in quite good agreement with experimental evidence. (orig./HP)

  3. Modeling a nuclear reactor for experimental purposes

    International Nuclear Information System (INIS)

    Berta, V.T.

    1980-01-01

    The Loss-of-Fluid Test (LOFT) Facility is a scale model of a commercial PWR and is as fully functional and operational as the generic commercial counterpart. LOFT was designed and built for experimental purposes as part of the overall NRC reactor safety research program. The purpose of LOFT is to assess the capability of reactor safety systems to perform their intended functions during occurrences of off-normal conditions in a commercial nuclear reactor. Off-normal conditions arising from large and small break loss-of-coolant accidents (LOCA), operational transients, and anticipated transients without scram (ATWS) were to be investigated. This paper describes the LOFT model of the generic PWR and summarizes the experiments that have been conducted in the context of the significant findings involving the complex transient thermal-hydraulics and the consequent effects on the commercial reactor analytical licensing techniques. Through these techniques the validity of the LOFT model as a scaled counterpart of the generic PWR is shown

  4. Entropy Characterization of Random Network Models

    Directory of Open Access Journals (Sweden)

    Pedro J. Zufiria

    2017-06-01

    Full Text Available This paper elaborates on the Random Network Model (RNM as a mathematical framework for modelling and analyzing the generation of complex networks. Such framework allows the analysis of the relationship between several network characterizing features (link density, clustering coefficient, degree distribution, connectivity, etc. and entropy-based complexity measures, providing new insight on the generation and characterization of random networks. Some theoretical and computational results illustrate the utility of the proposed framework.

  5. CHARACTERIZING AND MODELING FERRITE-CORE PROBES

    International Nuclear Information System (INIS)

    Sabbagh, Harold A.; Murphy, R. Kim; Sabbagh, Elias H.; Aldrin, John C.

    2010-01-01

    In this paper, we accurately and carefully characterize a ferrite-core probe that is widely used for aircraft inspections. The characterization starts with the development of a model that can be executed using the proprietary volume-integral code, VIC-3D(c), and then the model is fitted to measured multifrequency impedance data taken with the probe in freespace and over samples of a titanium alloy and aluminum. Excellent results are achieved, and will be discussed.

  6. Experimental models for Murray’s law

    Science.gov (United States)

    Akita, Dai; Kunita, Itsuki; Fricker, Mark D.; Kuroda, Shigeru; Sato, Katsuhiko; Nakagaki, Toshiyuki

    2017-01-01

    Transport networks are ubiquitous in multicellular organisms and include leaf veins, fungal mycelia and blood vessels. While transport of materials and signals through the network plays a crucial role in maintaining the living system, the transport capacity of the network can best be understood in terms of hydrodynamics. We report here that plasmodium from the large, single-celled amoeboid Physarum was able to construct a hydrodynamically optimized vein-network when evacuating biomass from confined arenas of various shapes through a narrow exit. Increasingly thick veins developed towards the exit, and the network spanned the arena via repetitive bifurcations to give a branching tree. The Hausdorff distance from all parts of the plasmodium to the vein network was kept low, whilst the hydrodynamic conductivity from distal parts of the network to the exit was equivalent, irrespective of the arena shape. This combination of spatial patterning and differential vein thickening served to evacuate biomass at an equivalent rate across the entire arena. The scaling relationship at the vein branches was determined experimentally to be 2.53-3.29, consistent with predictions from Murray’s law. Furthermore, we show that mathematical models for self-organised, adaptive transport in Physarum simulate the experimental network organisation well if the scaling coefficient of the current-reinforcement rule is set to 3. In simulations, this resulted in rapid development of an optimal network that minimised the combined volume and frictional energy in comparison with other scaling coefficients. This would predict that the boundary shear forces within each vein are constant throughout the network, and would be consistent with a feedback mechanism based on a sensing a threshold shear at the vein wall.

  7. Experimental models for Murray’s law

    International Nuclear Information System (INIS)

    Akita, Dai; Kunita, Itsuki; Fricker, Mark D; Kuroda, Shigeru; Sato, Katsuhiko; Nakagaki, Toshiyuki

    2017-01-01

    Transport networks are ubiquitous in multicellular organisms and include leaf veins, fungal mycelia and blood vessels. While transport of materials and signals through the network plays a crucial role in maintaining the living system, the transport capacity of the network can best be understood in terms of hydrodynamics. We report here that plasmodium from the large, single-celled amoeboid Physarum was able to construct a hydrodynamically optimized vein-network when evacuating biomass from confined arenas of various shapes through a narrow exit. Increasingly thick veins developed towards the exit, and the network spanned the arena via repetitive bifurcations to give a branching tree. The Hausdorff distance from all parts of the plasmodium to the vein network was kept low, whilst the hydrodynamic conductivity from distal parts of the network to the exit was equivalent, irrespective of the arena shape. This combination of spatial patterning and differential vein thickening served to evacuate biomass at an equivalent rate across the entire arena. The scaling relationship at the vein branches was determined experimentally to be 2.53–3.29, consistent with predictions from Murray’s law. Furthermore, we show that mathematical models for self-organised, adaptive transport in Physarum simulate the experimental network organisation well if the scaling coefficient of the current-reinforcement rule is set to 3. In simulations, this resulted in rapid development of an optimal network that minimised the combined volume and frictional energy in comparison with other scaling coefficients. This would predict that the boundary shear forces within each vein are constant throughout the network, and would be consistent with a feedback mechanism based on a sensing a threshold shear at the vein wall. (paper)

  8. Experimental Characterization Of The Interaction Between Carbon Fiber Composite Prepregs During The Preforming Process

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Weizhao; Zhang, Zixuan; Lu, Jie; Wang, Q Jane; Su, Xuming; Zeng, Danielle; Mirdamadi, Mansour; Cao, Jian

    2016-04-06

    Carbon fiber composites have received growing attention because of their high performance. One economic method to manufacturing the composite parts is the sequence of forming followed by the compression molding process. In this sequence, the preforming procedure forms the prepreg, which is the composite with the uncured resin, to the product geometry while the molding process cures the resin. Slip between different prepreg layers is observed in the preforming step and this paper reports a method to characterize the properties of the interaction between different prepreg layers, which is critical to predictive modeling and design optimization. An experimental setup was established to evaluate the interactions at various industrial production conditions. The experimental results were analyzed for an in-depth understanding about how the temperature, the relative sliding speed, and the fiber orientation affect the tangential interaction between two prepreg layers. The interaction factors measured from these experiments will be implemented in the computational preforming program.

  9. Standard Model theory calculations and experimental tests

    International Nuclear Information System (INIS)

    Cacciari, M.; Hamel de Monchenault, G.

    2015-01-01

    To present knowledge, all the physics at the Large Hadron Collider (LHC) can be described in the framework of the Standard Model (SM) of particle physics. Indeed the newly discovered Higgs boson with a mass close to 125 GeV seems to confirm the predictions of the SM. Thus, besides looking for direct manifestations of the physics beyond the SM, one of the primary missions of the LHC is to perform ever more stringent tests of the SM. This requires not only improved theoretical developments to produce testable predictions and provide experiments with reliable event generators, but also sophisticated analyses techniques to overcome the formidable experimental environment of the LHC and perform precision measurements. In the first section, we describe the state of the art of the theoretical tools and event generators that are used to provide predictions for the production cross sections of the processes of interest. In section 2, inclusive cross section measurements with jets, leptons and vector bosons are presented. Examples of differential cross sections, charge asymmetries and the study of lepton pairs are proposed in section 3. Finally, in section 4, we report studies on the multiple production of gauge bosons and constraints on anomalous gauge couplings

  10. Experimental characterization of graphene by electrostatic resonance frequency tuning

    NARCIS (Netherlands)

    Sajadi, B.; Alijani, F.; Davidovikj, D.; Goosen, J.F.L.; Steeneken, P.G.; van Keulen, A.

    2017-01-01

    In the last decade, graphene membranes have drawn tremendous attention due to their potential application in Nano-Electro-Mechanical Systems. In this paper, we show that the frequency response curves of graphene resonators are powerful tools for their dynamic characterization and for extracting

  11. Multi-model approach to characterize human handwriting motion.

    Science.gov (United States)

    Chihi, I; Abdelkrim, A; Benrejeb, M

    2016-02-01

    This paper deals with characterization and modelling of human handwriting motion from two forearm muscle activity signals, called electromyography signals (EMG). In this work, an experimental approach was used to record the coordinates of a pen tip moving on the (x, y) plane and EMG signals during the handwriting act. The main purpose is to design a new mathematical model which characterizes this biological process. Based on a multi-model approach, this system was originally developed to generate letters and geometric forms written by different writers. A Recursive Least Squares algorithm is used to estimate the parameters of each sub-model of the multi-model basis. Simulations show good agreement between predicted results and the recorded data.

  12. Experimental oligopolies modeling: A dynamic approach based on heterogeneous behaviors

    Science.gov (United States)

    Cerboni Baiardi, Lorenzo; Naimzada, Ahmad K.

    2018-05-01

    In the rank of behavioral rules, imitation-based heuristics has received special attention in economics (see [14] and [12]). In particular, imitative behavior is considered in order to understand the evidences arising in experimental oligopolies which reveal that the Cournot-Nash equilibrium does not emerge as unique outcome and show that an important component of the production at the competitive level is observed (see e.g.[1,3,9] or [7,10]). By considering the pioneering groundbreaking approach of [2], we build a dynamical model of linear oligopolies where heterogeneous decision mechanisms of players are made explicit. In particular, we consider two different types of quantity setting players characterized by different decision mechanisms that coexist and operate simultaneously: agents that adaptively adjust their choices towards the direction that increases their profit are embedded with imitator agents. The latter ones use a particular form of proportional imitation rule that considers the awareness about the presence of strategic interactions. It is noteworthy that the Cournot-Nash outcome is a stationary state of our models. Our thesis is that the chaotic dynamics arousing from a dynamical model, where heterogeneous players are considered, are capable to qualitatively reproduce the outcomes of experimental oligopolies.

  13. Experimental validation of solid rocket motor damping models

    Science.gov (United States)

    Riso, Cristina; Fransen, Sebastiaan; Mastroddi, Franco; Coppotelli, Giuliano; Trequattrini, Francesco; De Vivo, Alessio

    2017-12-01

    In design and certification of spacecraft, payload/launcher coupled load analyses are performed to simulate the satellite dynamic environment. To obtain accurate predictions, the system damping properties must be properly taken into account in the finite element model used for coupled load analysis. This is typically done using a structural damping characterization in the frequency domain, which is not applicable in the time domain. Therefore, the structural damping matrix of the system must be converted into an equivalent viscous damping matrix when a transient coupled load analysis is performed. This paper focuses on the validation of equivalent viscous damping methods for dynamically condensed finite element models via correlation with experimental data for a realistic structure representative of a slender launch vehicle with solid rocket motors. A second scope of the paper is to investigate how to conveniently choose a single combination of Young's modulus and structural damping coefficient—complex Young's modulus—to approximate the viscoelastic behavior of a solid propellant material in the frequency band of interest for coupled load analysis. A scaled-down test article inspired to the Z9-ignition Vega launcher configuration is designed, manufactured, and experimentally tested to obtain data for validation of the equivalent viscous damping methods. The Z9-like component of the test article is filled with a viscoelastic material representative of the Z9 solid propellant that is also preliminarily tested to investigate the dependency of the complex Young's modulus on the excitation frequency and provide data for the test article finite element model. Experimental results from seismic and shock tests performed on the test configuration are correlated with numerical results from frequency and time domain analyses carried out on its dynamically condensed finite element model to assess the applicability of different equivalent viscous damping methods to describe

  14. Experimental study of mass boiling in a porous medium model

    International Nuclear Information System (INIS)

    Sapin, Paul

    2014-01-01

    This manuscript presents a pore-scale experimental study of convective boiling heat transfer in a two-dimensional porous medium. The purpose is to deepen the understanding of thermohydraulics of porous media saturated with multiple fluid phases, in order to enhance management of severe accidents in nuclear reactors. Indeed, following a long-lasting failure in the cooling system of a pressurized water reactor (PWR) or a boiling water reactor (BWR) and despite the lowering of the control rods that stops the fission reaction, residual power due to radioactive decay keeps heating up the core. This induces water evaporation, which leads to the drying and degradation of the fuel rods. The resulting hot debris bed, comparable to a porous heat-generating medium, can be cooled down by reflooding, provided a water source is available. This process involves intense boiling mechanisms that must be modelled properly. The experimental study of boiling in porous media presented in this thesis focuses on the influence of different pore-scale boiling regimes on local heat transfer. The experimental setup is a model porous medium made of a bundle of heating cylinders randomly placed between two ceramic plates, one of which is transparent. Each cylinder is a resistance temperature detector (RTD) used to give temperature measurements as well as heat generation. Thermal measurements and high-speed image acquisition allow the effective heat exchanges to be characterized according to the observed local boiling regimes. This provides precious indications precious indications for the type of correlations used in the non-equilibrium macroscopic model used to model reflooding process. (author) [fr

  15. Experimental validation of solid rocket motor damping models

    Science.gov (United States)

    Riso, Cristina; Fransen, Sebastiaan; Mastroddi, Franco; Coppotelli, Giuliano; Trequattrini, Francesco; De Vivo, Alessio

    2018-06-01

    In design and certification of spacecraft, payload/launcher coupled load analyses are performed to simulate the satellite dynamic environment. To obtain accurate predictions, the system damping properties must be properly taken into account in the finite element model used for coupled load analysis. This is typically done using a structural damping characterization in the frequency domain, which is not applicable in the time domain. Therefore, the structural damping matrix of the system must be converted into an equivalent viscous damping matrix when a transient coupled load analysis is performed. This paper focuses on the validation of equivalent viscous damping methods for dynamically condensed finite element models via correlation with experimental data for a realistic structure representative of a slender launch vehicle with solid rocket motors. A second scope of the paper is to investigate how to conveniently choose a single combination of Young's modulus and structural damping coefficient—complex Young's modulus—to approximate the viscoelastic behavior of a solid propellant material in the frequency band of interest for coupled load analysis. A scaled-down test article inspired to the Z9-ignition Vega launcher configuration is designed, manufactured, and experimentally tested to obtain data for validation of the equivalent viscous damping methods. The Z9-like component of the test article is filled with a viscoelastic material representative of the Z9 solid propellant that is also preliminarily tested to investigate the dependency of the complex Young's modulus on the excitation frequency and provide data for the test article finite element model. Experimental results from seismic and shock tests performed on the test configuration are correlated with numerical results from frequency and time domain analyses carried out on its dynamically condensed finite element model to assess the applicability of different equivalent viscous damping methods to describe

  16. SoilEffects - start characterization of the experimental soil

    DEFF Research Database (Denmark)

    Løes, Anne-Kristin; Johansen, Anders; Pommeresche, Reidun

    -14). The aim of the SoilEffects project is to identify potential risks and benefits for soil fertility when animal manure is anaerobically digested for biogas production. The field experiment was established on Tingvoll research farm in 2011. A biogas plant was built at this farm in 2010, to digest the manure...... in spring, no legumes are grown, and aboveground plant material is removed at harvest. This practice is intended to stress the maintenance of soil organic matter in the arable system, to possibly reveal clearer effects of the experimental treatments. Within each cropping system, five experimental treatments...... by ignition loss was 11.3 % in the grass and 6.6 % in the arable system. Analyzed by total-C measurements, the corresponding SOM values were 11.03 % and 5.97 %. In Norwegian soil, SOM values between 3 and 6 % are regarded as high humus contents (“moldrik”), whereas values between 6 and 12 % are regarded...

  17. Experimental characterization of GIT-8 plasma opening switch

    International Nuclear Information System (INIS)

    Chuvatin, A.; Rouille, C.; Etlicher, B.; Kim, A.; Loginov, S.; Kokshenev, V.; Kovalchuk, B.

    1996-01-01

    High-current Plasma Opening Switch was experimentally studied on the GIT-8 inductive generator. Cordial laser interferometry allowed investigating the line-integrated POS plasma density dynamics during the switch operation. Recording of the axially distributed Bremsstrahlung radiation from the plasma region was used to determine the axial position where the opening started. The monitoring of fast plasma density oscillations with a characteristic frequency of ω ≅ 5 x 10 7 - 10 8 rad/s prior and during the opening is a new experimental achievement. A special study confirmed that such oscillations appear due to a plasma process. The oscillation frequency depended on the mean electron density as ω ∼ n e -0.5 . (author). 5 figs., 7 refs

  18. Characterization of fine aggregates in concrete by different experimental approaches

    OpenAIRE

    He, Huan; Courard, Luc; Pirard, Eric; Michel, Frédéric

    2011-01-01

    Being its major component, aggregate can occupy up to three-quarter of the volume of concrete. The structure of aggregate formed in hardened state impacts largely on mechanical and durability properties of concrete. On another hand, physical characteristics of aggregate are primarily assumed to be relevant to granular behavior of aggregate. Therefore, characterization of aggregate is of high relevance to concrete studies. In this study, different types of fine aggregate used in concrete, name...

  19. SoilEffects – start characterization of the experimental soil

    OpenAIRE

    Løes, Anne-Kristin; Johansen, Anders; Pommeresche, Reidun; Riley, Hugh

    2013-01-01

    This report describes the establishment, experimental plan and initial soil characteristics of the field experiment linked to the project “Effects of anaerobically digested manure on soil fertility - establishment of a long-term study under Norwegian conditions” (SoilEffects, 2010-14). The aim of the SoilEffects project is to identify potential risks and benefits for soil fertility when animal manure is anaerobically digested for biogas production. The field experiment was established on...

  20. Experimental Characterization of Piezoelectric Radial Field Diaphragms for Fluidic Control

    Science.gov (United States)

    Bryant, R. G.; Kavli, S. E.; Thomas, R. A., Jr.; Darji, K. J.; Mossi, K. M.

    2004-01-01

    NASA has recently developed a new piezoelectric actuator, the Radial Field Diaphragm or RFD. This actuator uses a radially-directed electric field to generate concentric out-of-plane (Z-axis) motion that allows this packaged device to be used as a pump or valve diaphragm. In order to efficiently use this new active device, experimental determination of pressure, flow rate, mechanical work, power consumption and overall efficiency needs to be determined by actually building a pump. However, without an optimized pump design, it is difficult to assess the quality of the data, as these results are inherent to the actual pump. Hence, separate experiments must be conducted in order to generate independent results to help guide the design criteria and pump quality. This paper focuses on the experiments used to generate the RFD's operational parameters and then compares these results to the experimentally determined results of several types of ball pumps. Also discussed are how errors are inherently introduced into the experiments, the pump design, experimental hardware and their effects on the overall system efficiency.

  1. Biomass thermochemical gasification: Experimental studies and modeling

    Science.gov (United States)

    Kumar, Ajay

    The overall goals of this research were to study the biomass thermochemical gasification using experimental and modeling techniques, and to evaluate the cost of industrial gas production and combined heat and power generation. This dissertation includes an extensive review of progresses in biomass thermochemical gasification. Product gases from biomass gasification can be converted to biopower, biofuels and chemicals. However, for its viable commercial applications, the study summarizes the technical challenges in the gasification and downstream processing of product gas. Corn stover and dried distillers grains with solubles (DDGS), a non-fermentable byproduct of ethanol production, were used as the biomass feedstocks. One of the objectives was to determine selected physical and chemical properties of corn stover related to thermochemical conversion. The parameters of the reaction kinetics for weight loss were obtained. The next objective was to investigate the effects of temperature, steam to biomass ratio and equivalence ratio on gas composition and efficiencies. DDGS gasification was performed on a lab-scale fluidized-bed gasifier with steam and air as fluidizing and oxidizing agents. Increasing the temperature resulted in increases in hydrogen and methane contents and efficiencies. A model was developed to simulate the performance of a lab-scale gasifier using Aspen Plus(TM) software. Mass balance, energy balance and minimization of Gibbs free energy were applied for the gasification to determine the product gas composition. The final objective was to optimize the process by maximizing the net energy efficiency, and to estimate the cost of industrial gas, and combined heat and power (CHP) at a biomass feedrate of 2000 kg/h. The selling price of gas was estimated to be 11.49/GJ for corn stover, and 13.08/GJ for DDGS. For CHP generation, the electrical and net efficiencies were 37 and 86%, respectively for corn stover, and 34 and 78%, respectively for DDGS. For

  2. Characterization of Growth Hormone Resistance in Experimental and Ulcerative Colitis

    DEFF Research Database (Denmark)

    Soendergaard, Christoffer; Kvist, Peter Helding; Thygesen, Peter

    2017-01-01

    Growth hormone (GH) resistance may develop as a consequence of inflammation during conditions such as inflammatory bowel disease, encompassing ulcerative colitis (UC). However, the specific role of the GH-insulin growth factor (IGF)-1-axis and/or the functional consequences of GH resistance......) proteins. These effects are driven by pro-inflammatory mediators (tumor necrosis factor (TNF)-α, interleukin (IL)-1β and IL-6) as confirmed using primary epithelial cells. Treatment of experimental colitis with GH increased IGF-1 and body weight of the mice, but had no effects on colonic inflammation...

  3. Injury Based on Its Study in Experimental Models

    Directory of Open Access Journals (Sweden)

    M. Mendes-Braz

    2012-01-01

    Full Text Available The present review focuses on the numerous experimental models used to study the complexity of hepatic ischemia/reperfusion (I/R injury. Although experimental models of hepatic I/R injury represent a compromise between the clinical reality and experimental simplification, the clinical transfer of experimental results is problematic because of anatomical and physiological differences and the inevitable simplification of experimental work. In this review, the strengths and limitations of the various models of hepatic I/R are discussed. Several strategies to protect the liver from I/R injury have been developed in animal models and, some of these, might find their way into clinical practice. We also attempt to highlight the fact that the mechanisms responsible for hepatic I/R injury depend on the experimental model used, and therefore the therapeutic strategies also differ according to the model used. Thus, the choice of model must therefore be adapted to the clinical question being answered.

  4. Protection of estrogen in portal hypertension gastropathy: an experimental model

    Directory of Open Access Journals (Sweden)

    Maria Isabel Morgan-Martins

    2011-09-01

    Full Text Available CONTEXT: Portal hypertension is a complication secondary to cirrhosis that is characterized by increased blood flow and/or vascular resistance in the portal system, causing the appearance of a hyperdynamic collateral circulation. Partial portal vein ligation is an experimental model used in rats to study the pathophysiological mechanisms involved in pre-hepatic portal hypertension. Estrogen E2 is an antioxidant molecule with various physiological actions. OBJECTIVES: To evaluate the antioxidant activity of endogenous estrogen in an experimental model of partial portal vein ligation by comparing intact with castrated rats. METHODS: Twenty Wistar rats, weighing on average 250 g were used and divided into four groups: sham-operated (SO; intact (I with partial portal vein ligation (I + PPVL, castrated (C and castrated with partial ligation of the vein (C + PPVL. Day 1: castration or sham-operation; day 7, PPVL surgery; on day 15 post-PPVL, portal pressure in the mesenteric vein of rats was measured on polygraph Letica. Lipid peroxidation in the stomach was assessed using the technique of thiobarbituric acid reactive substances and activity of antioxidant enzymes superoxide dismutase, catalase and glutathione peroxidase. Statistical analysis was done with ANOVA - Student-Newman-Keuls (mean ± SE, and P<0.05 was considered as significant. RESULTS: Portal pressure was significantly increased in C + PPVL as compared to the other groups. There was no significant difference in the group of intact rats. TBARS showed significant damage in C and C + PPVL in relation to others. Antioxidant enzymes were significantly increased in the castrated rats with subsequent PPVL as compared to the other groups. CONCLUSION: We suggest that estrogen E2 plays a protective role in intact compared with castrated rats because it presents hydrophenolic radicals in its molecule, thus acting as an antioxidant in this experimental model.

  5. Protection of estrogen in portal hypertension gastropathy: an experimental model.

    Science.gov (United States)

    Morgan-Martins, Maria Isabel; Jacques, Simone Iahnig; Hartmann, Renata Minuzzo; Marques, Camila Moraes; Marroni, Cláudio Augusto; Marroni, Norma Possa

    2011-01-01

    Portal hypertension is a complication secondary to cirrhosis that is characterized by increased blood flow and/or vascular resistance in the portal system, causing the appearance of a hyperdynamic collateral circulation. Partial portal vein ligation is an experimental model used in rats to study the pathophysiological mechanisms involved in pre-hepatic portal hypertension. Estrogen E2 is an antioxidant molecule with various physiological actions. To evaluate the antioxidant activity of endogenous estrogen in an experimental model of partial portal vein ligation by comparing intact with castrated rats. Twenty Wistar rats, weighing on average 250 g were used and divided into four groups: sham-operated (SO); intact (I) with partial portal vein ligation (I + PPVL), castrated (C) and castrated with partial ligation of the vein (C + PPVL). Day 1: castration or sham-operation; day 7, PPVL surgery; on day 15 post-PPVL, portal pressure in the mesenteric vein of rats was measured on polygraph Letica. Lipid peroxidation in the stomach was assessed using the technique of thiobarbituric acid reactive substances and activity of antioxidant enzymes superoxide dismutase, catalase and glutathione peroxidase. Statistical analysis was done with ANOVA - Student-Newman-Keuls (mean ± SE), and P<0.05 was considered as significant. Portal pressure was significantly increased in C + PPVL as compared to the other groups. There was no significant difference in the group of intact rats. TBARS showed significant damage in C and C + PPVL in relation to others. Antioxidant enzymes were significantly increased in the castrated rats with subsequent PPVL as compared to the other groups. We suggest that estrogen E2 plays a protective role in intact compared with castrated rats because it presents hydrophenolic radicals in its molecule, thus acting as an antioxidant in this experimental model.

  6. Prospects of experimentally reachable beyond Standard Model ...

    Indian Academy of Sciences (India)

    2016-01-06

    Jan 6, 2016 ... Since then, the theory has been experimentally verified to a ... Despite the fact that SM has unravelled the gauge origin of fundamental forces and the structure of Universe while successfully confronting numerous ...

  7. Experimental Human Cell and Tissue Models of Pemphigus

    Science.gov (United States)

    van der Wier, Gerda; Pas, Hendri H.; Jonkman, Marcel F.

    2010-01-01

    Pemphigus is a chronic mucocutaneous autoimmune bullous disease that is characterized by loss of cell-cell contact in skin and/or mucous membranes. Past research has successfully identified desmosomes as immunological targets and has demonstrated that acantholysis is initiated through direct binding of IgG. The exact mechanisms of acantholysis, however, are still missing. Experimental model systems have contributed considerably to today's knowledge and are still a favourite tool of research. In this paper we will describe to what extent human cell and tissue models represent the in vivo situation, for example, organ cultures of human skin, keratinocyte cultures, and human skin grafted on mice and, furthermore, how suitable they are to study the pathogenesis of pemphigus. Organ cultures closely mimic the architecture of the epidermis but are less suitable to answer posed biochemical questions. Cultured keratinocyte monolayers are convenient in this respect, but their desmosomal make-up in terms of adhesion molecules does not exactly reflect the in vivo situation. Reconstituted skin is a relatively new model that approaches organ culture. In models of human skin grafted on mice, acantholysis can be studied in actual human skin but now with all the advantages of an animal model. PMID:20585596

  8. Experimental characterization of gasoline sprays under highly evaporating conditions

    Science.gov (United States)

    Khan, Muhammad Mahabat; Sheikh, Nadeem Ahmed; Khalid, Azfar; Lughmani, Waqas Akbar

    2018-05-01

    An experimental investigation of multistream gasoline sprays under highly evaporating conditions is carried out in this paper. Temperature increase of fuel and low engine pressure could lead to flash boiling. The spray shape is normally modified significantly under flash boiling conditions. The spray plumes expansion along with reduction in the axial momentum causes the jets to merge and creates a low-pressure area below the injector's nozzle. These effects initiate the collapse of spray cone and lead to the formation of a single jet plume or a big cluster like structure. The collapsing sprays reduces exposed surface and therefore they last longer and subsequently penetrate more. Spray plume momentum increase, jet plume reduction and spray target widening could delay or prevent the closure condition and limit the penetration (delayed formation of the cluster promotes evaporation). These spray characteristics are investigated experimentally using shadowgraphy, for five and six hole injectors, under various boundary conditions. Six hole injectors produce more collapsing sprays in comparison to five hole injector due to enhanced jet to jet interactions. The spray collapse tendency reduces with increase in injection pressure due high axial momentum of spray plumes. The spray evaporation rates of five hole injector are observed to be higher than six hole injectors. Larger spray cone angles of the six hole injectors promote less penetrating and less collapsing sprays.

  9. Experimental characterization of variable output refractive beamshapers using freeform elements

    Science.gov (United States)

    Shultz, Jason A.; Smilie, Paul J.; Dutterer, Brian S.; Davies, Matthew A.; Suleski, Thomas J.

    2014-09-01

    We present experimental results from variable output refractive beam shapers based on freeform optical surfaces. Two freeform elements in close proximity comprise a beam shaper that maps a circular Gaussian input to a circular `flat-top' output. Different lateral relative shifts between the elements result in a varying output diameter while maintaining the uniform irradiance distribution. We fabricated the beam shaping elements in PMMA using multi-axis milling on a Moore Nanotech 350FG diamond machining center and tested with a 632.8 nm Gaussian input. Initial optical testing confirmed both the predicted beam shaping and variable functionality, but with poor output uniformity. The effects of surface finish on optical performance were investigated using LightTrans VirtualLabTM to perform physical optics simulations of the milled freeform surfaces. These simulations provided an optimization path for determining machining parameters to improve the output uniformity of the beam shaping elements. A second variable beam shaper based on a super-Gaussian output was designed and fabricated using the newly determined machining parameters. Experimental test results from the second beam shaper showed outputs with significantly higher quality, but also suggest additional areas of study for further improvements in uniformity.

  10. A new cubic phantom for PET/CT dosimetry: Experimental and Monte Carlo characterization

    International Nuclear Information System (INIS)

    Belinato, Walmir; Silva, Rogerio M.V.; Souza, Divanizia N.; Santos, William S.; Caldas, Linda V.E.; Perini, Ana P.; Neves, Lucio P.

    2015-01-01

    In recent years, positron emission tomography (PET) associated with multidetector computed tomography (MDCT) has become a diagnostic technique widely disseminated to evaluate various malignant tumors and other diseases. However, during PET/CT examinations, the doses of ionizing radiation experienced by the internal organs of patients may be substantial. To study the doses involved in PET/CT procedures, a new cubic phantom of overlapping acrylic plates was developed and characterized. This phantom has a deposit for the placement of the fluorine-18 fluoro-2-deoxy-D-glucose ( 18 F-FDG) solution. There are also small holes near the faces for the insertion of optically stimulated luminescence dosimeters (OSLD). The holes for OSLD are positioned at different distances from the 18 F-FDG deposit. The experimental results were obtained in two PET/CT devices operating with different parameters. Differences in the absorbed doses were observed in OSLD measurements due to the non-orthogonal positioning of the detectors inside the phantom. This phantom was also evaluated using Monte Carlo simulations, with the MCNPX code. The phantom and the geometrical characteristics of the equipment were carefully modeled in the MCNPX code, in order to develop a new methodology form comparison of experimental and simulated results, as well as to allow the characterization of PET/CT equipments in Monte Carlo simulations. All results showed good agreement, proving that this new phantom may be applied for these experiments. (authors)

  11. A new cubic phantom for PET/CT dosimetry: Experimental and Monte Carlo characterization

    Energy Technology Data Exchange (ETDEWEB)

    Belinato, Walmir [Departamento de Ensino, Instituto Federal de Educacao, Ciencia e Tecnologia da Bahia, Campus Vitoria da Conquista, Zabele, Av. Amazonas 3150, 45030-220 Vitoria da Conquista, BA (Brazil); Silva, Rogerio M.V.; Souza, Divanizia N. [Departamento de Fisica, Universidade Federal de Sergipe-UFS, Sao Cristovao, Sergipe (Brazil); Santos, William S.; Caldas, Linda V.E. [Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP, Av. Prof. Lineu Prestes, 2242, Cidade Universitaria, 05508-000 Sao Paulo SP (Brazil); Perini, Ana P.; Neves, Lucio P. [Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP, Av. Prof. Lineu Prestes, 2242, Cidade Universitaria, 05508-000 Sao Paulo SP (Brazil); Instituto de Fisica, Universidade Federal de Uberlandia, Caixa Postal 593, 38400-902, Uberlandia, MG (Brazil)

    2015-07-01

    In recent years, positron emission tomography (PET) associated with multidetector computed tomography (MDCT) has become a diagnostic technique widely disseminated to evaluate various malignant tumors and other diseases. However, during PET/CT examinations, the doses of ionizing radiation experienced by the internal organs of patients may be substantial. To study the doses involved in PET/CT procedures, a new cubic phantom of overlapping acrylic plates was developed and characterized. This phantom has a deposit for the placement of the fluorine-18 fluoro-2-deoxy-D-glucose ({sup 18}F-FDG) solution. There are also small holes near the faces for the insertion of optically stimulated luminescence dosimeters (OSLD). The holes for OSLD are positioned at different distances from the {sup 18}F-FDG deposit. The experimental results were obtained in two PET/CT devices operating with different parameters. Differences in the absorbed doses were observed in OSLD measurements due to the non-orthogonal positioning of the detectors inside the phantom. This phantom was also evaluated using Monte Carlo simulations, with the MCNPX code. The phantom and the geometrical characteristics of the equipment were carefully modeled in the MCNPX code, in order to develop a new methodology form comparison of experimental and simulated results, as well as to allow the characterization of PET/CT equipments in Monte Carlo simulations. All results showed good agreement, proving that this new phantom may be applied for these experiments. (authors)

  12. Experimental Characterization of Ionic Polymer Metal Composite as a Novel Fractional Order Element

    Directory of Open Access Journals (Sweden)

    Riccardo Caponetto

    2013-01-01

    Full Text Available Ionic polymer metal composites (IPMCs are electroactive materials made of ionic polymer thin membranes with platinum metallization on their surfaces. They are interesting materials due to not only their electromechanical applications as transducers but also to their electrochemical features and the relationship between the ionic/solvent current and the potential field. Their electrochemical properties thus suggest the possibility for exploiting them as compact fractional-order elements (FOEs with a view of defining fabrication processes and production strategies that assure the desired performances. In this paper, the experimental electrical characterization of a brand new IPMC setup in a fixed sandwich configuration is proposed. Two IPMC devices with different platinum absorption times (5 h and 20 h are characterized through experimental data: first, a preliminary linearity study is performed for a fixed input voltage amplitude in order to determine the frequency region where IPMC can be approximated as linear; then, a frequency analysis is carried out in order to identify a coherent fractional-order dynamics in the bode diagrams. Such analyses take the first steps towards a simplified model of IPMC as a compact electronic FOE for which the fractional exponent value depends on fabrication parameters as the absorption time.

  13. Tupaia belangeri as an experimental animal model for viral infection.

    Science.gov (United States)

    Tsukiyama-Kohara, Kyoko; Kohara, Michinori

    2014-01-01

    Tupaias, or tree shrews, are small mammals that are similar in appearance to squirrels. The morphological and behavioral characteristics of the group have been extensively characterized, and despite previously being classified as primates, recent studies have placed the group in its own family, the Tupaiidae. Genomic analysis has revealed that the genus Tupaia is closer to humans than it is to rodents. In addition, tupaias are susceptible to hepatitis B virus and hepatitis C virus. The only other experimental animal that has been demonstrated to be sensitive to both of these viruses is the chimpanzee, but restrictions on animal testing have meant that experiments using chimpanzees have become almost impossible. Consequently, the development of the tupaia for use as an animal infection model could become a powerful tool for hepatitis virus research and in preclinical studies on drug development.

  14. Sparse linear models: Variational approximate inference and Bayesian experimental design

    International Nuclear Information System (INIS)

    Seeger, Matthias W

    2009-01-01

    A wide range of problems such as signal reconstruction, denoising, source separation, feature selection, and graphical model search are addressed today by posterior maximization for linear models with sparsity-favouring prior distributions. The Bayesian posterior contains useful information far beyond its mode, which can be used to drive methods for sampling optimization (active learning), feature relevance ranking, or hyperparameter estimation, if only this representation of uncertainty can be approximated in a tractable manner. In this paper, we review recent results for variational sparse inference, and show that they share underlying computational primitives. We discuss how sampling optimization can be implemented as sequential Bayesian experimental design. While there has been tremendous recent activity to develop sparse estimation, little attendance has been given to sparse approximate inference. In this paper, we argue that many problems in practice, such as compressive sensing for real-world image reconstruction, are served much better by proper uncertainty approximations than by ever more aggressive sparse estimation algorithms. Moreover, since some variational inference methods have been given strong convex optimization characterizations recently, theoretical analysis may become possible, promising new insights into nonlinear experimental design.

  15. Sparse linear models: Variational approximate inference and Bayesian experimental design

    Energy Technology Data Exchange (ETDEWEB)

    Seeger, Matthias W [Saarland University and Max Planck Institute for Informatics, Campus E1.4, 66123 Saarbruecken (Germany)

    2009-12-01

    A wide range of problems such as signal reconstruction, denoising, source separation, feature selection, and graphical model search are addressed today by posterior maximization for linear models with sparsity-favouring prior distributions. The Bayesian posterior contains useful information far beyond its mode, which can be used to drive methods for sampling optimization (active learning), feature relevance ranking, or hyperparameter estimation, if only this representation of uncertainty can be approximated in a tractable manner. In this paper, we review recent results for variational sparse inference, and show that they share underlying computational primitives. We discuss how sampling optimization can be implemented as sequential Bayesian experimental design. While there has been tremendous recent activity to develop sparse estimation, little attendance has been given to sparse approximate inference. In this paper, we argue that many problems in practice, such as compressive sensing for real-world image reconstruction, are served much better by proper uncertainty approximations than by ever more aggressive sparse estimation algorithms. Moreover, since some variational inference methods have been given strong convex optimization characterizations recently, theoretical analysis may become possible, promising new insights into nonlinear experimental design.

  16. Analytical and Experimental Studies of Leak Location and Environment Characterization for the International Space Station

    Science.gov (United States)

    Woronowicz, Michael; Abel, Joshua; Autrey, David; Blackmon, Rebecca; Bond, Tim; Brown, Martin; Buffington, Jesse; Cheng, Edward; DeLatte, Danielle; Garcia, Kelvin; hide

    2014-01-01

    The International Space Station program is developing a robotically-operated leak locator tool to be used externally. The tool would consist of a Residual Gas Analyzer for partial pressure measurements and a full range pressure gauge for total pressure measurements. The primary application is to detect NH3 coolant leaks in the ISS thermal control system. An analytical model of leak plume physics is presented that can account for effusive flow as well as plumes produced by sonic orifices and thruster operations. This model is used along with knowledge of typical RGA and full range gauge performance to analyze the expected instrument sensitivity to ISS leaks of various sizes and relative locations ("directionality"). The paper also presents experimental results of leak simulation testing in a large thermal vacuum chamber at NASA Goddard Space Flight Center. This test characterized instrument sensitivity as a function of leak rates ranging from 1 lb-mass/yr. to about 1 lb-mass/day. This data may represent the first measurements collected by an RGA or ion gauge system monitoring off-axis point sources as a function of location and orientation. Test results are compared to the analytical model and used to propose strategies for on-orbit leak location and environment characterization using the proposed instrument while taking into account local ISS conditions and the effects of ram/wake flows and structural shadowing within low Earth orbit.

  17. Analytical and experimental studies of leak location and environment characterization for the international space station

    Energy Technology Data Exchange (ETDEWEB)

    Woronowicz, Michael; Blackmon, Rebecca; Brown, Martin [Stinger Ghaffarian Technologies, Inc, 7701 Greenbelt Rd, Greenbelt, MD 20770 (United States); Abel, Joshua; Hawk, Doug [Alliant Techsystems, Inc, 5050 Powder Mill Road, Beltsville, Maryland 20705 (United States); Autrey, David; Glenn, Jodie [Lockheed Martin, 1300 Hercules, Houston, TX 77058 (United States); Bond, Tim; Buffington, Jesse [NASA Johnson Space Flight Center, 2101 NASA Pkwy, Houston, TX 77058 (United States); Cheng, Edward; Ma, Jonathan; Rossetti, Dino [Conceptual Analytics, 8209 Woburn Abbey Rd, Glenn Dale, MD 20769 (United States); DeLatte, Danielle [ASRC Federal Space and Defense, 7000 Muirkirk Meadows Drive, Suite 100, Beltsville, MD 20705 (United States); Garcia, Kelvin; Mohammed, Jelila; Montt de Garcia, Kristina; Perry, Radford [NASA Goddard Space Flight Center, 8800 Greenbelt Rd, Greenbelt, MD 20771 (United States); Tull, Kimathi [Jackson and Tull, 7375 Executive Pl, Lanham, MD 20706 (United States); Warren, Eric [Wyle STE Group, 1290 Hercules Ave, Houston, TX 77058-2769 (United States)

    2014-12-09

    The International Space Station program is developing a robotically-operated leak locator tool to be used externally. The tool would consist of a Residual Gas Analyzer for partial pressure measurements and a full range pressure gauge for total pressure measurements. The primary application is to demonstrate the ability to detect NH{sub 3} coolant leaks in the ISS thermal control system. An analytical model of leak plume physics is presented that can account for effusive flow as well as plumes produced by sonic orifices and thruster operations. This model is used along with knowledge of typical RGA and full range gauge performance to analyze the expected instrument sensitivity to ISS leaks of various sizes and relative locations (“directionality”). The paper also presents experimental results of leak simulation testing in a large thermal vacuum chamber at NASA Goddard Space Flight Center. This test characterized instrument sensitivity as a function of leak rates ranging from 1 lb{sub m/}/yr. to about 1 lb{sub m}/day. This data may represent the first measurements collected by an RGA or ion gauge system monitoring off-axis point sources as a function of location and orientation. Test results are compared to the analytical model and used to propose strategies for on-orbit leak location and environment characterization using the proposed instrument while taking into account local ISS conditions and the effects of ram/wake flows and structural shadowing within low Earth orbit.

  18. Analytical and experimental studies of leak location and environment characterization for the international space station

    International Nuclear Information System (INIS)

    Woronowicz, Michael; Blackmon, Rebecca; Brown, Martin; Abel, Joshua; Hawk, Doug; Autrey, David; Glenn, Jodie; Bond, Tim; Buffington, Jesse; Cheng, Edward; Ma, Jonathan; Rossetti, Dino; DeLatte, Danielle; Garcia, Kelvin; Mohammed, Jelila; Montt de Garcia, Kristina; Perry, Radford; Tull, Kimathi; Warren, Eric

    2014-01-01

    The International Space Station program is developing a robotically-operated leak locator tool to be used externally. The tool would consist of a Residual Gas Analyzer for partial pressure measurements and a full range pressure gauge for total pressure measurements. The primary application is to demonstrate the ability to detect NH 3 coolant leaks in the ISS thermal control system. An analytical model of leak plume physics is presented that can account for effusive flow as well as plumes produced by sonic orifices and thruster operations. This model is used along with knowledge of typical RGA and full range gauge performance to analyze the expected instrument sensitivity to ISS leaks of various sizes and relative locations (“directionality”). The paper also presents experimental results of leak simulation testing in a large thermal vacuum chamber at NASA Goddard Space Flight Center. This test characterized instrument sensitivity as a function of leak rates ranging from 1 lb m/ /yr. to about 1 lb m /day. This data may represent the first measurements collected by an RGA or ion gauge system monitoring off-axis point sources as a function of location and orientation. Test results are compared to the analytical model and used to propose strategies for on-orbit leak location and environment characterization using the proposed instrument while taking into account local ISS conditions and the effects of ram/wake flows and structural shadowing within low Earth orbit

  19. Experimental characterization of a binary actuated parallel manipulator

    Science.gov (United States)

    Giuseppe, Carbone

    2016-05-01

    This paper describes the BAPAMAN (Binary Actuated Parallel MANipulator) series of parallel manipulators that has been conceived at Laboratory of Robotics and Mechatronics (LARM). Basic common characteristics of BAPAMAN series are described. In particular, it is outlined the use of a reduced number of active degrees of freedom, the use of design solutions with flexural joints and Shape Memory Alloy (SMA) actuators for achieving miniaturization, cost reduction and easy operation features. Given the peculiarities of BAPAMAN architecture, specific experimental tests have been proposed and carried out with the aim to validate the proposed design and to evaluate the practical operation performance and the characteristics of a built prototype, in particular, in terms of operation and workspace characteristics.

  20. Experimental Characterization of Wings for a Hawkmoth-Sized Micro Air Vehicle

    Science.gov (United States)

    2014-03-27

    butterfly where the modeshapes were found to be identical with the Hawkmoth, lending more credence to the assertion that the wing modal ratios...EXPERIMENTAL CHARACTERIZATION OF WINGS FOR A HAWKMOTH-SIZED MICRO AIR VEHICLE THESIS Zachary R. Brown, Lieutenant Commander, USN AFIT-ENY-14-M-10...of the U.S. Government and is not subject to copyright protection in the United States. AFIT-ENY-14-M-10 EXPERIMENTAL CHARACTERIZATION OF WINGS FOR A

  1. Experimental characterization of the water transport properties of PEM fuel cells diffusion media

    Science.gov (United States)

    Ramos-Alvarado, Bladimir; Sole, Joshua D.; Hernandez-Guerrero, Abel; Ellis, Michael W.

    2012-11-01

    A full experimental characterization of the liquid water transport properties of Toray TGP-090 paper is carried out in this work. Porosity, capillary pressure curves (capillary pressure-saturation relationships), absolute permeability, and relative permeability are obtained via experimental procedures. Porosity was determined using two methods, both aimed to obtain the solid volume of the network of fibers comprising the carbon paper. Capillary pressure curves were obtained using a gas displacement porosimeter where liquid water is injected using a syringe pump and the capillary pressure is recorded using a differential pressure transducer. Absolute and relative permeability were also measured with an apparatus designed at Virginia Tech. Absolute permeability was calculated at different flow rates using nitrogen. On the other hand, relative permeability was a more complicated task to carry out giving the complexity (two-phase flow condition) of this property. All of the water transport properties of Toray TGP-090 were studied under the effects of wet-proofing (PTFE treatment) and compression. Some observations were that wet-proofing reduces the porosity of the raw material, increases the hydrophobicity (Pc-S curves), and reduces the permeability of the material. Similar effects were observed for compression, where compressed material exhibited trends similar to those of wet-proofing effects. The results presented here will allow a more accurate modeling of PEMFCs, providing an experimentally verified alternative to the assumptions frequently employed.

  2. Modelling and characterization of colliding-pulse mode-locked (CPM) quantum well lasers. [MPS1

    DEFF Research Database (Denmark)

    Bischoff, Svend; Brorson, S.D.; Franck, T.

    1996-01-01

    A theoretical and experimental study of passive colliding pulse mode-locked quantum well lasers is presented. The theoretical model for the gain dynamics is based on semi-classical density matrixequations. The gain dynamics are characterized exp...

  3. Experimental study and modelling of iron ore reduction by hydrogen

    International Nuclear Information System (INIS)

    Wagner, D.

    2008-01-01

    In an effort to find new ways to drastically reduce the CO 2 emissions from the steel industry (ULCOS project), the reduction of iron ore by pure hydrogen in a shaft furnace was investigated. The work consisted of literature, experimental, and modelling studies. The chemical reaction and its kinetics were analysed on the basis of thermogravimetric experiments and physicochemical characterizations of partially reduced samples. A specific kinetic model was designed, which simulates the successive reactions, the different steps of mass transport, and possible iron sintering, at the particle scale. Finally, a 2-dimensional numerical model of a shaft furnace was developed. It depicts the variation of the solid and gas temperatures and compositions throughout the reactor. One original feature of the model is using the law of additive characteristic times for calculating the reaction rates. This allowed us to handle both the particle and the reactor scale, while keeping reasonable calculation time. From the simulation results, the influence of the process parameters was assessed. Optimal operating conditions were concluded, which reveal the efficiency of the hydrogen process. (author)

  4. Toxin-Induced Experimental Models of Learning and Memory Impairment.

    Science.gov (United States)

    More, Sandeep Vasant; Kumar, Hemant; Cho, Duk-Yeon; Yun, Yo-Sep; Choi, Dong-Kug

    2016-09-01

    Animal models for learning and memory have significantly contributed to novel strategies for drug development and hence are an imperative part in the assessment of therapeutics. Learning and memory involve different stages including acquisition, consolidation, and retrieval and each stage can be characterized using specific toxin. Recent studies have postulated the molecular basis of these processes and have also demonstrated many signaling molecules that are involved in several stages of memory. Most insights into learning and memory impairment and to develop a novel compound stems from the investigations performed in experimental models, especially those produced by neurotoxins models. Several toxins have been utilized based on their mechanism of action for learning and memory impairment such as scopolamine, streptozotocin, quinolinic acid, and domoic acid. Further, some toxins like 6-hydroxy dopamine (6-OHDA), 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) and amyloid-β are known to cause specific learning and memory impairment which imitate the disease pathology of Parkinson's disease dementia and Alzheimer's disease dementia. Apart from these toxins, several other toxins come under a miscellaneous category like an environmental pollutant, snake venoms, botulinum, and lipopolysaccharide. This review will focus on the various classes of neurotoxin models for learning and memory impairment with their specific mechanism of action that could assist the process of drug discovery and development for dementia and cognitive disorders.

  5. Multiscale modelling and experimentation of hydrogen embrittlement in aerospace materials

    Science.gov (United States)

    Jothi, Sathiskumar

    Pulse plated nickel and nickel based superalloys have been used extensively in the Ariane 5 space launcher engines. Large structural Ariane 5 space launcher engine components such as combustion chambers with complex microstructures have usually been manufactured using electrodeposited nickel with advanced pulse plating techniques with smaller parts made of nickel based superalloys joined or welded to the structure to fabricate Ariane 5 space launcher engines. One of the major challenges in manufacturing these space launcher components using newly developed materials is a fundamental understanding of how different materials and microstructures react with hydrogen during welding which can lead to hydrogen induced cracking. The main objective of this research has been to examine and interpret the effects of microstructure on hydrogen diffusion and hydrogen embrittlement in (i) nickel based superalloy 718, (ii) established and (iii) newly developed grades of pulse plated nickel used in the Ariane 5 space launcher engine combustion chamber. Also, the effect of microstructures on hydrogen induced hot and cold cracking and weldability of three different grades of pulse plated nickel were investigated. Multiscale modelling and experimental methods have been used throughout. The effect of microstructure on hydrogen embrittlement was explored using an original multiscale numerical model (exploiting synthetic and real microstructures) and a wide range of material characterization techniques including scanning electron microscopy, 2D and 3D electron back scattering diffraction, in-situ and ex-situ hydrogen charged slow strain rate tests, thermal spectroscopy analysis and the Varestraint weldability test. This research shows that combined multiscale modelling and experimentation is required for a fundamental understanding of microstructural effects in hydrogen embrittlement in these materials. Methods to control the susceptibility to hydrogen induced hot and cold cracking and

  6. Individual Hearing Loss: Characterization, Modelling, Compensation Strategies

    DEFF Research Database (Denmark)

    Santurette, Sébastien; Dau, Torsten; Christensen-Dalsgaard, Jakob

    2016-01-01

    account for such individual differences, which make it challenging to find adequate compensation strategies in hearing devices. How to characterize, model, and compensate for individual hearing loss were the main topics of the fifth International Symposium on Auditory and Audiological Research (ISAAR...

  7. Experimental characterization of PZT fibers using IDE electrodes

    Science.gov (United States)

    Wyckoff, Nicholas; Ben Atitallah, Hassene; Ounaies, Zoubeida

    2016-04-01

    Lead zirconate titanate (PZT) fibers are mainly used in active fiber composites (AFC) where they are embedded in a polymer matrix. Interdigitated electrodes (IDE) along the direction of the fibers are used to achieve planar actuation, hereby exploiting the d33 coefficient of PZT. When embedded in the AFC, the PZT fibers are subjected to mechanical loading as well as non-uniform electric field as a result of the IDEs. Therefore, it is important to characterize the electrical and electromechanical behavior of these fibers ex-situ using the IDE electrodes to assess the impact of nonuniform electric field on the properties of the fibers. For that reason, this work aims at quantifying the impact of IDE electrodes on the electrical and electromechanical behavior of PZT fibers, which is necessary for their successful implementation in devices like AFC. The tested fibers were purchased from Advanced Cerametrics and they have an average diameter of 250 micrometers. The IDE electrodes were screen printed on an acrylic substrate. The PZT fibers were subjected to frequency sweeps at low voltages to determine permittivity for parallel and interdigitated electrodes. The piezoelectric e33 constant is determined from electromechanical testing of PZT fibers in parallel electrodes to compare the electromechanical behavior for PZT in bulk and fiber form. The dielectric constant and e33 were found to be lower for the IDE and parallel electrodes compared to bulk but comparable to results published in literature.

  8. Characterization of large volume HPGe detectors. Part II: Experimental results

    International Nuclear Information System (INIS)

    Bruyneel, Bart; Reiter, Peter; Pascovici, Gheorghe

    2006-01-01

    Measurements on a 12-fold segmented, n-type, large volume, irregular shaped HPGe detector were performed in order to determine the parameters of anisotropic mobility for electrons and holes as charge carriers created by γ-ray interactions. To characterize the electron mobility the complete outer detector surface was scanned in small steps employing photopeak interactions at 60keV. A precise measurement of the hole drift anisotropy was performed with 356keV γ-rays. The drift velocity anisotropy and crystal geometry cause considerable rise time differences in pulse shapes depending on the position of the spatial charge carrier creation. Pulse shapes of direct and transient signals are reproduced by weighting potential calculations with high precision. The measured angular dependence of rise times is caused by the anisotropic mobility, crystal geometry, changing field strength and space charge effects. Preamplified signals were processed employing digital spectroscopy electronics. Response functions, crosstalk contributions and averaging procedures were taken into account implying novel methods due to the segmentation of the Ge-crystal and digital signal processing electronics

  9. Experimental Characterization of Dielectric Properties in Fluid Saturated Artificial Shales

    Directory of Open Access Journals (Sweden)

    Roman Beloborodov

    2017-01-01

    Full Text Available High dielectric contrast between water and hydrocarbons provides a useful method for distinguishing between producible layers of reservoir rocks and surrounding media. Dielectric response at high frequencies is related to the moisture content of rocks. Correlations between the dielectric permittivity and specific surface area can be used for the estimation of elastic and geomechanical properties of rocks. Knowledge of dielectric loss-factor and relaxation frequency in shales is critical for the design of techniques for effective hydrocarbon extraction and production from unconventional reservoirs. Although applicability of dielectric measurements is intriguing, the data interpretation is very challenging due to many factors influencing the dielectric response. For instance, dielectric permittivity is determined by mineralogical composition of solid fraction, volumetric content and composition of saturating fluid, rock microstructure and geometrical features of its solid components and pore space, temperature, and pressure. In this experimental study, we investigate the frequency dependent dielectric properties of artificial shale rocks prepared from silt-clay mixtures via mechanical compaction. Samples are prepared with various clay contents and pore fluids of different salinity and cation compositions. Measurements of dielectric properties are conducted in two orientations to investigate the dielectric anisotropy as the samples acquire strongly oriented microstructures during the compaction process.

  10. A new laboratory-scale experimental facility for detailed aerothermal characterizations of volumetric absorbers

    Science.gov (United States)

    Gomez-Garcia, Fabrisio; Santiago, Sergio; Luque, Salvador; Romero, Manuel; Gonzalez-Aguilar, Jose

    2016-05-01

    This paper describes a new modular laboratory-scale experimental facility that was designed to conduct detailed aerothermal characterizations of volumetric absorbers for use in concentrating solar power plants. Absorbers are generally considered to be the element with the highest potential for efficiency gains in solar thermal energy systems. The configu-ration of volumetric absorbers enables concentrated solar radiation to penetrate deep into their solid structure, where it is progressively absorbed, prior to being transferred by convection to a working fluid flowing through the structure. Current design trends towards higher absorber outlet temperatures have led to the use of complex intricate geometries in novel ceramic and metallic elements to maximize the temperature deep inside the structure (thus reducing thermal emission losses at the front surface and increasing efficiency). Although numerical models simulate the conjugate heat transfer mechanisms along volumetric absorbers, they lack, in many cases, the accuracy that is required for precise aerothermal validations. The present work aims to aid this objective by the design, development, commissioning and operation of a new experimental facility which consists of a 7 kWe (1.2 kWth) high flux solar simulator, a radiation homogenizer, inlet and outlet collector modules and a working section that can accommodate volumetric absorbers up to 80 mm × 80 mm in cross-sectional area. Experimental measurements conducted in the facility include absorber solid temperature distributions along its depth, inlet and outlet air temperatures, air mass flow rate and pressure drop, incident radiative heat flux, and overall thermal efficiency. In addition, two windows allow for the direct visualization of the front and rear absorber surfaces, thus enabling full-coverage surface temperature measurements by thermal imaging cameras. This paper presents the results from the aerothermal characterization of a siliconized silicon

  11. Experimental and numerical characterization of wind-induced pressure coefficients on nuclear buildings and chimney exhausts

    Energy Technology Data Exchange (ETDEWEB)

    Ricciardi, Laurent, E-mail: laurent.ricciardi@irsn.fr; Gélain, Thomas; Soares, Sandrine

    2015-10-15

    Highlights: • Experiments on scale models of nuclear buildings and chimney exhausts were performed. • Pressure coefficient fields on buildings are shown for various wind directions. • Evolution of pressure coefficient vs U/W ratio is given for various chimney exhausts. • RANS simulations using SST k–ω turbulence model were performed on most studied cases. • A good agreement is overall observed, with Root Mean Square Deviation lower than 0.15. - Abstract: Wind creates pressure effects on different surfaces of buildings according to their exposure to the wind, in particular at external communications. In nuclear facilities, these effects can change contamination transfers inside the building and can even lead to contamination release into the environment, especially in damaged (ventilation stopped) or accidental situations. The diversity of geometries of facilities requires the use of a validated code for predicting pressure coefficients, which characterize the wind effect on the building walls and the interaction between the wind and chimney exhaust. The first aim of a research program launched by the French Institut de Radioprotection et de Sûreté Nucléaire (IRSN), was therefore to acquire experimental data of the mean pressure coefficients for different geometries of buildings and chimneys through wind tunnel tests and then to validate a CFD code (ANSYS CFX) from these experimental results. The simulations were performed using a steady RANS approach and a two-equation SST k–ω turbulence model. After a mesh sensitivity study for one configuration of building and chimney, a comparison was carried out between the numerical and experimental values for other studied configurations. This comparison was generally satisfactory, averaged over all measurement points, with values of Root Mean Square Deviations lower than 0.15 for most cases.

  12. Experimental system model of a primary active fluid

    International Nuclear Information System (INIS)

    Deseigne, Julien

    2010-01-01

    Collective motion, such as flocks of birds or shoals of fish, is ubiquitous in nature. Such fundamentally out-of-equilibrium phenomena may be described with the new conceptual background of polar active matter, a system of polar particles which enables to use provided energy in order to move in their own directions. A 2D experimental system of vibrated polar disks that interact only by contact has been set up. These disks behave as random walkers, whose trajectories are characterized by a persistence length greater than their size and controlled by the angular fluctuations of their polarity. The interplay between the hard-core repulsion and the persistence of the motion leads to complex alignment modes. For instance, only 10 pc of the binary collisions correspond to an effective ferromagnetic alignment. Yet, spontaneous collective motion inside the system characterized by giant fluctuations of density have been observed. These results reveal the robustness of the polar order observed in theoretical and numerical models of 2D polar active matter on substrate

  13. Tesla Coil Theoretical Model and its Experimental Verification

    Directory of Open Access Journals (Sweden)

    Voitkans Janis

    2014-12-01

    Full Text Available In this paper a theoretical model of Tesla coil operation is proposed. Tesla coil is described as a long line with distributed parameters in a single-wire form, where the line voltage is measured across electrically neutral space. By applying the principle of equivalence of single-wire and two-wire schemes an equivalent two-wire scheme can be found for a single-wire scheme and the already known long line theory can be applied to the Tesla coil. A new method of multiple reflections is developed to characterize a signal in a long line. Formulas for calculation of voltage in Tesla coil by coordinate and calculation of resonance frequencies are proposed. The theoretical calculations are verified experimentally. Resonance frequencies of Tesla coil are measured and voltage standing wave characteristics are obtained for different output capacities in the single-wire mode. Wave resistance and phase coefficient of Tesla coil is obtained. Experimental measurements show good compliance with the proposed theory. The formulas obtained in this paper are also usable for a regular two-wire long line with distributed parameters.

  14. Models of experimental saccular aneurysms of carotid arteries in canine

    International Nuclear Information System (INIS)

    Zhang Haixia; Cheng Yingsheng; Li Minghua

    2006-01-01

    Objective: To study the availability by making experimental saccular aneurysm models of carotid arteries in canine similar to human intracranial aneurysms. Methods: Twenty healthy canines with experimental saccular side-wall aneurysms of carotid arteries were created successfully by surgery. Results: Forty experimental saccular side-wall aneurysms of carotid arteries were created successfully with 36 aneurysms and parent arteries maintaining patency with each other and four spontaneously occluded confirmed by angiography. Model successful rate reached 90%. Conclusions: Experimental saccular side-wall aneurysms of carotid arteries in canines were one of best models created for simulating human intracranial aneurysms. (authors)

  15. Experimental comparison of models for ultrafast impact ionization is silicon

    DEFF Research Database (Denmark)

    Tarekegne, Abebe Tilahun; Iwaszczuk, Krzysztof; Jepsen, Peter Uhd

    2016-01-01

    We compare experimentally the exponential and quadratic (Keldysh formula) impact ionization models using THz induced impact ionization in silicon. We demonstrate that the exponential model offers the best description of impact ionization process for ultrashort electric filed pulses.......We compare experimentally the exponential and quadratic (Keldysh formula) impact ionization models using THz induced impact ionization in silicon. We demonstrate that the exponential model offers the best description of impact ionization process for ultrashort electric filed pulses....

  16. Experimental modeling of swirl flows in power plants

    Science.gov (United States)

    Shtork, S. I.; Litvinov, I. V.; Gesheva, E. S.; Tsoy, M. A.; Skripkin, S. G.

    2018-03-01

    The article presents an overview of the methods and approaches to experimental modeling of various thermal and hydropower units - furnaces of pulverized coal boilers and flow-through elements of hydro turbines. The presented modeling approaches based on a combination of experimentation and rapid prototyping of working parts may be useful in optimizing energy equipment to improve safety and efficiency of industrial energy systems.

  17. DMFC performance and methanol cross-over: Experimental analysis and model validation

    Energy Technology Data Exchange (ETDEWEB)

    Casalegno, A.; Marchesi, R. [Dipartimento di Energia, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milano (Italy)

    2008-10-15

    A combined experimental and modelling approach is proposed to analyze methanol cross-over and its effect on DMFC performance. The experimental analysis is performed in order to allow an accurate investigation of methanol cross-over influence on DMFC performance, hence measurements were characterized in terms of uncertainty and reproducibility. The findings suggest that methanol cross-over is mainly determined by diffusion transport and affects cell performance partly via methanol electro-oxidation at the cathode. The modelling analysis is carried out to further investigate methanol cross-over phenomenon. A simple model evaluates the effectiveness of two proposed interpretations regarding methanol cross-over and its effects. The model is validated using the experimental data gathered. Both the experimental analysis and the proposed and validated model allow a substantial step forward in the understanding of the main phenomena associated with methanol cross-over. The findings confirm the possibility to reduce methanol cross-over by optimizing anode feeding. (author)

  18. Improving the physiological realism of experimental models

    NARCIS (Netherlands)

    Vinnakota, Kalyan C.; Cha, Chae Y.; Rorsman, Patrik; Balaban, Robert S.; La Gerche, Andre; Wade-Martins, Richard; Beard, Daniel A.; Jeneson, Jeroen A. L.

    The Virtual Physiological Human (VPH) project aims to develop integrative, explanatory and predictive computational models (C-Models) as numerical investigational tools to study disease, identify and design effective therapies and provide an in silico platform for drug screening. Ultimately, these

  19. Experimental models of the gut microbiome

    NARCIS (Netherlands)

    Venema, K.; Abbeele, P. van den

    2013-01-01

    The human gut contains a diverse microbiota with large potential to influence health. Given the difficulty to access the main sites of the gut, in vitro models have been developed to dynamically monitor microbial processes at the site of metabolic activity. These models range from simple batch

  20. Experimental characterization of the hydro-mechanical behaviour of Meuse/Haute-Marne argilites

    International Nuclear Information System (INIS)

    Escoffier, S.

    2002-04-01

    Within the framework of a feasibility study of underground radioactive waste repository the experimental characterization of the coupled behavior of the host layer is of first importance. This work concerns the experimental characterization in laboratory of the poro-elastic behavior of argillite which constitutes the host layer of the future underground laboratory of ANDRA located at the limit of the Meuse/Haute-Marne. The theoretical approach is the Mechanics of Porous Media defined by Coussy [1991] which has the advantage of providing a formulation of the behavior laws using measurable parameters in laboratory. The difficulties or the feasibility of the characterization tests of these rocks coupled behavior are related to their very low permeability which requires an adaptation of the experimental devices initially used on more permeable rocks. Initially a synthesis on the knowledge of the poro-elastic parameters of Meuse/Haute-Marne argillite is given. Thereafter a first approach of the use of the studies of sensitivity as tools of decision-making aid is proposed. The experimental difficulties encountered by the various experimenters are illustrated by the diversity of the experimental choices, the test duration or by the results disparity. Because of economic, political and ecological stake, the studies of sensitivity could make it possible to direct the experimental efforts by giving indications on the dominating parameters in the coupled behavior of a rock. In the second time after the presentation of the test results of physical characterization 3 types of tests are described: permeability test (pulse test), determination of Biot coefficient under odometric loading and isotropic drained test. The complexity of these tests is related to the attack of the experimental limits. They are presented in detail: theoretical recalls, experimental set up, experimental protocol, unfolding and test results. (author)

  1. [An experimental model of transgastric ooforectomy using a porcine model].

    Science.gov (United States)

    Tomulescu, V; Gheorghe, C; Piţigoi, D; Kosa, A; Ciocarlan, M; Pietrăreanu, D; Turcu, F; Copăescu, C; Droc, G; Popescu, H; Grigorescu, B; Stănciulea, O; Herlea, V; Popescu, I

    2010-01-01

    Transabdominal routes for surgery entail general anaesthesia with its inherent risks and complications (prolonged hospital stay, abdominal incisions that may be difficult in obese patients). Minimally invasive procedures require shorter hospitalization, have shorter recovery periods, less postoperative discomfort, and lower morbidity and complications. The purpose of this study was to use a porcine model to determine the feasibility and the safety of organ resection (oophorectomy and tubectomy). 10 Big White pigs between 25-30 kg underwent transgastric ooforectomy. The first 5 cases were performed in a hybrid procedure (laparoscopic-NOTES) in order to have a better control and supervise the maneuvers done by the mobile endoscope and to guide in the abdominal cavity. Adnexectomy was possible in all ten experiments. Full operative time (from starting endoscopy to complete gastrectomy closing) was 180 min to 270 min. The gastric defect closing was the most difficult manoever lasting from 10 min with OTSC clips to 100 using endoloops and clips. The animals have tolerated well the experiments and there have been no remarkable incidents during our 10 experments. In only one case a bleeding from gastotomy required electric coagulation. Transgastric ooforectomy in an experimental model is a procedure that requires advanced laparoscopical and endoscopical skills. Our early results are promissing. Its application in humans needs further confirmation of the method.

  2. Cooking Potatoes: Experimentation and Mathematical Modeling.

    Science.gov (United States)

    Chen, Xiao Dong

    2002-01-01

    Describes a laboratory activity involving a mathematical model of cooking potatoes that can be solved analytically. Highlights the microstructure aspects of the experiment. Provides the key aspects of the results, detailed background readings, laboratory procedures and data analyses. (MM)

  3. Optimization of experimental human leukemia models (review

    Directory of Open Access Journals (Sweden)

    D. D. Pankov

    2012-01-01

    Full Text Available Actual problem of assessing immunotherapy prospects including antigenpecific cell therapy using animal models was covered in this review.Describe the various groups of currently existing animal models and methods of their creating – from different immunodeficient mice to severalvariants of tumor cells engraftment in them. The review addresses the possibility of tumor stem cells studying using mouse models for the leukemia treatment with adoptive cell therapy including WT1. Also issues of human leukemia cells migration and proliferation in a mice withdifferent immunodeficiency degree are discussed. To assess the potential immunotherapy efficacy comparison of immunodeficient mouse model with clinical situation in oncology patients after chemotherapy is proposed.

  4. Ideal Experimental Rat Models for Liver Diseases

    OpenAIRE

    Lee, Sang Woo; Kim, Sung Hoon; Min, Seon Ok; Kim, Kyung Sik

    2011-01-01

    There are many limitations for conducting liver disease research in human beings due to the high cost and potential ethical issues. For this reason, conducting a study that is difficult to perform in humans using appropriate animal models, can be beneficial in ascertaining the pathological physiology, and in developing new treatment modalities. However, it is difficult to determine the appropriate animal model which is suitable for research purposes, since every patient has different and dive...

  5. Ageing of palladium tritide: mechanical characterization, helium state and modelling

    International Nuclear Information System (INIS)

    Segard, M.

    2010-01-01

    Palladium is commonly used for the storage of tritium (the hydrogen radioactive isotope), since it forms a low-equilibrium-pressure and reversible tritide. Tritium decay into helium-3 is responsible for the ageing of the tritide, leading to the apparition of helium-3 bubbles for instance. Both experimental and theoretical aspects of this phenomenon are studied here.Previous works on ageing modelling led to two main models, dealing with:- Helium-3 bubbles nucleation (using a cellular automaton), - Bubbles growth (using continuum mechanics).These models were quite efficient, but their use was limited by the lack of input data and fitting experimental parameters.To get through these limitations, this work has consisted in studying the most relevant experimental data to improve the modelling of the palladium tritide ageing.The first part of this work was focused on the assessment of the mechanical properties of the palladium tritide (yield strength, ultimate strength, mechanical behaviour). They were deduced from the in situ tensile tests performed on palladium hydride and deuteride. In the second part, ageing characterization was undertaken, mainly focusing on: - Bubbles observations in palladium tritide using transmission electron microscopy, - Internal bubble pressure measurements using nuclear magnetic resonance, - Macroscopic swelling measurements using pycno-metry.The present work has led to significant progress in ageing understanding and has brought very valuable improvements to the modelling of such a phenomenon. (author) [fr

  6. Ideal Experimental Rat Models for Liver Diseases.

    Science.gov (United States)

    Lee, Sang Woo; Kim, Sung Hoon; Min, Seon Ok; Kim, Kyung Sik

    2011-05-01

    There are many limitations for conducting liver disease research in human beings due to the high cost and potential ethical issues. For this reason, conducting a study that is difficult to perform in humans using appropriate animal models, can be beneficial in ascertaining the pathological physiology, and in developing new treatment modalities. However, it is difficult to determine the appropriate animal model which is suitable for research purposes, since every patient has different and diverse clinical symptoms, adverse reactions, and complications due to the pathological physiology. Also, it is not easy to reproduce identically various clinical situations in animal models. Recently, the Guide for the Care and Use of Laboratory Animals has tightened up the regulations, and therefore it is advisable to select the appropriate animals and decide upon the appropriate quantities through scientific and systemic considerations before conducting animal testing. Therefore, in this review article the authors examined various white rat animal testing models and determined the appropriate usable rat model, and the pros and cons of its application in liver disease research. The authors believe that this review will be beneficial in selecting proper laboratory animals for research purposes.

  7. Experimental strategies for the identification and characterization of adhesive proteins in animals: a review

    Science.gov (United States)

    Hennebert, Elise; Maldonado, Barbara; Ladurner, Peter; Flammang, Patrick; Santos, Romana

    2015-01-01

    Adhesive secretions occur in both aquatic and terrestrial animals, in which they perform diverse functions. Biological adhesives can therefore be remarkably complex and involve a large range of components with different functions and interactions. However, being mainly protein based, biological adhesives can be characterized by classical molecular methods. This review compiles experimental strategies that were successfully used to identify, characterize and obtain the full-length sequence of adhesive proteins from nine biological models: echinoderms, barnacles, tubeworms, mussels, sticklebacks, slugs, velvet worms, spiders and ticks. A brief description and practical examples are given for a variety of tools used to study adhesive molecules at different levels from genes to secreted proteins. In most studies, proteins, extracted from secreted materials or from adhesive organs, are analysed for the presence of post-translational modifications and submitted to peptide sequencing. The peptide sequences are then used directly for a BLAST search in genomic or transcriptomic databases, or to design degenerate primers to perform RT-PCR, both allowing the recovery of the sequence of the cDNA coding for the investigated protein. These sequences can then be used for functional validation and recombinant production. In recent years, the dual proteomic and transcriptomic approach has emerged as the best way leading to the identification of novel adhesive proteins and retrieval of their complete sequences. PMID:25657842

  8. Experimental Verification of the Transient Model in an Enrichment Circuit

    International Nuclear Information System (INIS)

    Fernandino, Maria; Brasnarof, Daniel; Delmastro, Dario

    2003-01-01

    In the present work an experimental closed loop representing a single stage of an uranium gaseous diffusion enrichment cascade is described, loop that is used to experimentally validate an analytical model that describes the dynamics inside such a loop.The conditions established inside the experimental loop after a few working hours were reproduced by the analytical model, leaving the slower thermal phenomena taking place for future studies.Two kinds of perturbations were experimentally introduced: a change in the range of operation of one of the compressors and the addition of mass into the loop.Numerical and experimental results are compared and presented in this work. The analytical model proposed was verified against these two changes, with very good agreement in the time response and measured values.This analytical model allows us to determine the characteristic time response of the system

  9. Scaled Experimental Modeling of VHTR Plenum Flows

    Energy Technology Data Exchange (ETDEWEB)

    ICONE 15

    2007-04-01

    Abstract The Very High Temperature Reactor (VHTR) is the leading candidate for the Next Generation Nuclear Power (NGNP) Project in the U.S. which has the goal of demonstrating the production of emissions free electricity and hydrogen by 2015. Various scaled heated gas and water flow facilities were investigated for modeling VHTR upper and lower plenum flows during the decay heat portion of a pressurized conduction-cooldown scenario and for modeling thermal mixing and stratification (“thermal striping”) in the lower plenum during normal operation. It was concluded, based on phenomena scaling and instrumentation and other practical considerations, that a heated water flow scale model facility is preferable to a heated gas flow facility and to unheated facilities which use fluids with ranges of density to simulate the density effect of heating. For a heated water flow lower plenum model, both the Richardson numbers and Reynolds numbers may be approximately matched for conduction-cooldown natural circulation conditions. Thermal mixing during normal operation may be simulated but at lower, but still fully turbulent, Reynolds numbers than in the prototype. Natural circulation flows in the upper plenum may also be simulated in a separate heated water flow facility that uses the same plumbing as the lower plenum model. However, Reynolds number scaling distortions will occur at matching Richardson numbers due primarily to the necessity of using a reduced number of channels connected to the plenum than in the prototype (which has approximately 11,000 core channels connected to the upper plenum) in an otherwise geometrically scaled model. Experiments conducted in either or both facilities will meet the objectives of providing benchmark data for the validation of codes proposed for NGNP designs and safety studies, as well as providing a better understanding of the complex flow phenomena in the plenums.

  10. Experimental modeling of a deoiling hydrocyclone system

    DEFF Research Database (Denmark)

    Bram, Mads Valentin; Hassan, Abdiladif Ahmed; Hansen, Dennis Severin

    2015-01-01

    responses of PDR via dedicated experiments a set of first-order-plus-dead-time (FOPDT) models that represent the main characteristics of the concerned hydrocyclone system is developed and analyzed for the entire operating range. The obtained multiple FOPDT models can illustrate the system performance...... acrylic hydrocyclone was tested as proof of concept for obtaining its steady-state and dynamic performances. The steady-state performance is able to provide the proportional correlation between PDR and flow split which is essential for optimizing steady-state separation efficiency. By analyzing step...

  11. Experimental and modelling studies of infiltration

    International Nuclear Information System (INIS)

    Giudici, M.

    2004-01-01

    This presentation describes a study of infiltration in the unsaturated soil with the objective of estimating the recharge to a phreatic aquifer. The study area is at the border of the city of Milan (Northern Italy), which draws water for both domestic and industrial purposes from ground water resources located beneath the urban area. The rate of water pumping from the aquifer system has been varying during the XX century, depending upon the number of inhabitants and the development of industrial activities. This caused variations with time of the depth of the water table below the ground surface and in turn some emergencies: the two most prominent episodes correspond to the middle '70s, when the water table in the city centre was about 30 m below the undisturbed natural conditions, and to the last decade, when the water table has raised at a rate of approximately 1 m/year and caused infiltrations in deep constructions (garages and building foundations, the underground railways, etc.). We have developed four ground water flow models at different scales, which share some characteristics: they are based on quasi-3D approximation (horizontal flow in the aquifers and vertical flow in the aquitards), conservative finite-differences schemes for regular grid with square cells in the horizontal plane and are implemented with proprietary computer codes. Among the problems that were studied for the development of these models, I recall some numerical problems, related to the behaviour of the phreatic aquifer under conditions of strong exploitation. Model calibration and validation for ModMil has been performed with a two-stage process, i.e., using some of the available data for model calibration and the remaining data for model validation. The application of geophysical exploration techniques, in particular seismic and geo-electrical prospecting, has been very useful to complete the data and information on the hydro-geological structure obtained from stratigraphic logs

  12. Seismic velocities to characterize the soil-aquifer continuum on the Orgeval experimental basin (France)

    Science.gov (United States)

    Pasquet, S.; Ludovic, B.; Dhemaied, A.; Flipo, N.; Guérin, R.; Mouhri, A.; Faycal, R.; Vitale, Q.

    2013-12-01

    Among geophysical methods applied to hydrogeology, seismic prospecting is frequently confined to the characterization of aquifers geometry. The combined study of pressure- (P) and shear- (SH) wave velocities (respectively Vp and Vs) can however provide information about the aquifer parameters, as it is commonly done for most fluids in hydrocarbon exploration. This approach has recently been proposed in sandy aquifers with the estimation of Vp/Vs ratio. In order to address such issues in more complex aquifer systems (e.g. unconsolidated, heterogeneous or low-permeability media) we carried out P- and SH-wave seismic surveys on the Orgeval experimental basin (70 km east from Paris, France). This basin drains a multi-layer aquifer system monitored by a network of piezometers. The upper part of the aquifer system is characterized by tabular layers well delineated all over the basin thanks to Electrical Resistivity Tomography (ERT), Time Domain ElectroMagnetic (TDEM) soundings and wells. But the lateral variability of the intrinsic properties in each layer raises questions regarding the hydrodynamics of the upper aquifer and the validity of interpolations between piezometers. A simple interpretation of P- and SH-wave first arrivals for tabular models provides 1D velocity structures in very good agreement with the stratification anticipated from ERT and nearby geological logs. Vp/Vs ratios show a strong contrast at a depth consistent with the observed water table level, reinforcing the assumption of a free upper aquifer in the area. Similar experiments have to be conducted under different hydrological conditions to validate these observations. Anticipating the need to propose lateral applications of the method, we additionally performed tomographic inversions of the recorded data to retrieve 2D Vp and Vs models. If interpreted independently, both models fail to depict the stratification of the medium and the water table level cannot be straightforwardly identified

  13. CFD simulation of a burner for syngas characterization and experimental validation

    Energy Technology Data Exchange (ETDEWEB)

    Fantozzi, Francesco; Desideri, Umberto [University of Perugia (Italy). Dept. of Industrial Engineering], Emails: fanto@unipg.it, umberto.desideri@unipg.it; D' Amico, Michele [University of Perugia (Italy). Dept. of Energetic Engineering], E-mail: damico@crbnet.it

    2009-07-01

    Biomass and waste are distributed and renewable energy sources that may contribute effectively to sustainability if used on a small and micro scale. This requires the transformation through efficient technologies (gasification, pyrolysis and anaerobic digestion) into a suitable gaseous fuel to use in small internal combustion engines and gas turbines. The characterization of biomass derived syngas during combustion is therefore a key issue to improve the performance of small scale integrated plants because synthesis gas show significant differences with respect to Natural Gas (mixture of gases, low calorific value, hydrogen content, tar and particulate content) that may turn into ignition problems, combustion instabilities, difficulties in emission control and fouling. To this aim a burner for syngas combustion and LHV measurement through mass and energy balance was realized and connected to the rotary-kiln laboratory scale pyrolyzer at the Department of Industrial Engineering of the University of Perugia. A computational fluid dynamics (CFD) simulation of the burner was carried out considering the combustion of propane to investigate temperature and pressure distribution, heat transmission and distribution of the combustion products and by products. The simulation was carried out using the CFD program Star-CD. Before the simulation a geometrical model of the burner was built and the volume of model was subdivided in cells. A sensibility analysis of cells was carried out to estimate the approximation degree of the model. Experimental data about combustion emission were carried out with the propane combustion in the burner, the comparison between numerical results and experimental data was studied to validate the simulation for future works involved with the combustion of treated or raw (syngas with tar) syngas obtained from pyrolysis process. (author)

  14. Lung cancer risk models from experimental animals

    International Nuclear Information System (INIS)

    Gilbert, E.S.

    1988-03-01

    The objective of this paper is to present analyses of data based on methods that adequately account for time-related factors and competiting risks, and that yield results that are expressed in a form comparable to results obtained from recent analyses of epidemiological studies of humans exposed to radon and radon daughters. These epidemiological analyses have modeled the hazard, or age-specific death rates, as a function of factors such as dose and dose rate, time from exposure, and time from cessation of exposure. The starting point for many of the analyses of human data has been the constant relative risk modeling which the age-specific death rates are assumed to be a function of cumulative dose, and the risks due to exposure are assumed to be proportional to the age-specific baseline death rates. However, departures from this initial model, such as dependence of risks on age at risk and/or time from exposure, have been investigated. These analyses have frequently been based on a non-parametric model that requires minimal assumptions regarding the baseline risks and their dependence on age

  15. Isothermal coarse mixing: experimental and CFD modelling

    International Nuclear Information System (INIS)

    Gilbertson, M.A.; Kenning, D.B.R.; Hall, R.W.

    1992-01-01

    A plane, two-dimensional flow apparatus has been built which uses a jet of solid 6mm diameter balls to model a jet of molten drops falling into a tank of water to study premixing prior to a vapour explosion. Preliminary experiments with unheated stainless steel balls are here compared with computational fluid dynamics (CFD) calculations by the code CHYMES. (6 figures) (Author)

  16. New experimental model of multiple myeloma.

    Science.gov (United States)

    Telegin, G B; Kalinina, A R; Ponomarenko, N A; Ovsepyan, A A; Smirnov, S V; Tsybenko, V V; Homeriki, S G

    2001-06-01

    NSO/1 (P3x63Ay 8Ut) and SP20 myeloma cells were inoculated to BALB/c OlaHsd mice. NSO/1 cells allowed adequate stage-by-stage monitoring of tumor development. The adequacy of this model was confirmed in experiments with conventional cytostatics: prospidium and cytarabine caused necrosis of tumor cells and reduced animal mortality.

  17. Experimental characterization. Thermal and solar performance of houses built; Caracterizacion experimental. comportamiento termico y solar de viviendas construidas

    Energy Technology Data Exchange (ETDEWEB)

    Carrilo, A.; Jurado, L.; Molina, J. C.; Druet, L.

    2011-07-01

    In this communication we describe the calibration of a simulation model of a house. is the Energy Plus simulation program, and the experimental procedure is based on the method PSTAR (Subbarao, 1988) which are obtained adjustment factors that provide a quantitative interpretation of the discrepancies. (Author)

  18. Characterization of experimental cements with endodontic goal; Caracterizacao de cimentos experimentais com finalidade endodontica

    Energy Technology Data Exchange (ETDEWEB)

    Dantas, A.M.X.; Sousa, W.J.B.; Oliveira, E.D.C.; Carrodeguas, R.G.; Fook, M.V. Lia, E-mail: alana.mxd@hotmail [Universidade Federal de Campina Grande (CCT/UFCG), PB (Brazil). Unidade Academica de Engenharia de Materiais; Universidade Estadual da Paraiba (UEPB), Campina Grande, PB (Brazil). Departamento de Quimica

    2017-10-01

    The present study aimed to characterize experimental endodontic cements using as comparative parameter MTA cement. Two experimental endodontic cements were assessed: one based on 95% tri-strontium aluminate and 5% gypsum (CE1) and another based on 50% Sr{sub 3}Al{sub 2}O{sub 6} and 50% non-structural white cement (CE2). Experimental cements were manipulated and characterized by scanning electron microscopy (SEM), coupled to EDS mode, X-ray diffractometer (XRD) and Thermogravimetric (TG) analysis. Data analysis demonstrated that the particles of the materials used presented varied shapes and sizes, with similar elements and crystalline behavior. However, CE1 presented increased mass loss. Experimental cements presents similarities to MTA, nevertheless, further studies are encourage to determinate comparative properties with the commercially material. (author)

  19. PREDICTION MODELS OF GRAIN YIELD AND CHARACTERIZATION

    Directory of Open Access Journals (Sweden)

    Narciso Ysac Avila Serrano

    2009-06-01

    Full Text Available With the objective to characterize the grain yield of five cowpea cultivars and to find linear regression models to predict it, a study was developed in La Paz, Baja California Sur, Mexico. A complete randomized blocks design was used. Simple and multivariate analyses of variance were carried out using the canonical variables to characterize the cultivars. The variables cluster per plant, pods per plant, pods per cluster, seeds weight per plant, seeds hectoliter weight, 100-seed weight, seeds length, seeds wide, seeds thickness, pods length, pods wide, pods weight, seeds per pods, and seeds weight per pods, showed significant differences (P≤ 0.05 among cultivars. Paceño and IT90K-277-2 cultivars showed the higher seeds weight per plant. The linear regression models showed correlation coefficients ≥0.92. In these models, the seeds weight per plant, pods per cluster, pods per plant, cluster per plant and pods length showed significant correlations (P≤ 0.05. In conclusion, the results showed that grain yield differ among cultivars and for its estimation, the prediction models showed determination coefficients highly dependable.

  20. A refined model for characterizing x-ray multilayers

    International Nuclear Information System (INIS)

    Oren, A.L.; Henke, B.L.

    1987-12-01

    The ability to quickly and accurately characterize arbitrary multilayers is very valuable for not only can we use the characterizations to predict the reflectivity of a multilayer for any soft x-ray wavelength, we also can generalize the results to apply to other multilayers of the same type. In addition, we can use the characterizations as a means of evaluating various sputtering environments and refining sputtering techniques to obtain better multilayers. In this report we have obtained improved characterizations for sample molybdenum-silicon and vanadium-silicon multilayers. However, we only examined five crystals overall, so the conclusions that we could draw about the structure of general multilayers is limited. Research involving many multilayers manufactured under the same sputtering conditions is clearly in order. In order to best understand multilayer structures it may be necessary to further refine our model, e.g., adopting a Gaussian form for the interface regions. With such improvements we can expect even better agreement with experimental values and continued concurrence with other characterization techniques. 18 refs., 30 figs., 7 tabs

  1. New experimental model for training in videosurgery Novo modelo experimental para treinamento em videocirurgia

    Directory of Open Access Journals (Sweden)

    Danilo Malta Batista

    2012-10-01

    Full Text Available PURPOSE: To develop a new experimental model of lower cost for training in videosurgery. METHODS: This project was performed at the Nucleus of Experimental Surgery of the Bahiana School of Medicine and Public Health, based on previous models described in the literature and under the supervision of the full professor of Operative Technique and Experimental Surgery II. It was made a model cube-shaped, made of wood, with holes distributed in various locations, rubber stoppers for the holes and lined externally with carpet, and internally with laminate. RESULTS: The new experimental model is of low cost and reproduces quite faithfully several videosurgical procedures. CONCLUSION: Medical schools interested in the subject may adopt the new model for training in videosurgery without the need of high costs for making and using these models.OBJETIVO: Desenvolver um novo modelo experimental de baixo custo para treinamento em videocirurgia MÉTODOS: Este projeto foi conduzido no Núcleo de Cirurgia Experimental da Escola Bahiana de Medicina e Saúde Pública, baseado em modelos prévios descritos na literatura e sob a supervisão do professor titular de Técnica Operatória e Cirurgia Experimental II. Foi feito um modelo em formato de cubo, de madeira, com furos distribuídos em vários locais, tampas de borracha para os orifícios e forrado externamente com carpete e internamente com laminado. RESULTADOS: O novo modelo experimental desenvolvido é de baixo custo e reproduz de forma bastante fiel diversos procedimentos videocirúrgicos. CONCLUSÃO: Faculdades médicas interessadas no tema poderão adotar o novo modelo para o treinamento em videocirurgia sem que sejam necessários gastos elevados para a confecção e o uso desses modelos.

  2. Experimentally testing the standard cosmological model

    Energy Technology Data Exchange (ETDEWEB)

    Schramm, D.N. (Chicago Univ., IL (USA) Fermi National Accelerator Lab., Batavia, IL (USA))

    1990-11-01

    The standard model of cosmology, the big bang, is now being tested and confirmed to remarkable accuracy. Recent high precision measurements relate to the microwave background; and big bang nucleosynthesis. This paper focuses on the latter since that relates more directly to high energy experiments. In particular, the recent LEP (and SLC) results on the number of neutrinos are discussed as a positive laboratory test of the standard cosmology scenario. Discussion is presented on the improved light element observational data as well as the improved neutron lifetime data. alternate nucleosynthesis scenarios of decaying matter or of quark-hadron induced inhomogeneities are discussed. It is shown that when these scenarios are made to fit the observed abundances accurately, the resulting conclusions on the baryonic density relative to the critical density, {Omega}{sub b}, remain approximately the same as in the standard homogeneous case, thus, adding to the robustness of the standard model conclusion that {Omega}{sub b} {approximately} 0.06. This latter point is the deriving force behind the need for non-baryonic dark matter (assuming {Omega}{sub total} = 1) and the need for dark baryonic matter, since {Omega}{sub visible} < {Omega}{sub b}. Recent accelerator constraints on non-baryonic matter are discussed, showing that any massive cold dark matter candidate must now have a mass M{sub x} {approx gt} 20 GeV and an interaction weaker than the Z{sup 0} coupling to a neutrino. It is also noted that recent hints regarding the solar neutrino experiments coupled with the see-saw model for {nu}-masses may imply that the {nu}{sub {tau}} is a good hot dark matter candidate. 73 refs., 5 figs.

  3. Experimentally testing the standard cosmological model

    International Nuclear Information System (INIS)

    Schramm, D.N.

    1990-11-01

    The standard model of cosmology, the big bang, is now being tested and confirmed to remarkable accuracy. Recent high precision measurements relate to the microwave background; and big bang nucleosynthesis. This paper focuses on the latter since that relates more directly to high energy experiments. In particular, the recent LEP (and SLC) results on the number of neutrinos are discussed as a positive laboratory test of the standard cosmology scenario. Discussion is presented on the improved light element observational data as well as the improved neutron lifetime data. alternate nucleosynthesis scenarios of decaying matter or of quark-hadron induced inhomogeneities are discussed. It is shown that when these scenarios are made to fit the observed abundances accurately, the resulting conclusions on the baryonic density relative to the critical density, Ω b , remain approximately the same as in the standard homogeneous case, thus, adding to the robustness of the standard model conclusion that Ω b ∼ 0.06. This latter point is the deriving force behind the need for non-baryonic dark matter (assuming Ω total = 1) and the need for dark baryonic matter, since Ω visible b . Recent accelerator constraints on non-baryonic matter are discussed, showing that any massive cold dark matter candidate must now have a mass M x approx-gt 20 GeV and an interaction weaker than the Z 0 coupling to a neutrino. It is also noted that recent hints regarding the solar neutrino experiments coupled with the see-saw model for ν-masses may imply that the ν τ is a good hot dark matter candidate. 73 refs., 5 figs

  4. Experimental modeling methods in Industrial Engineering

    Directory of Open Access Journals (Sweden)

    Peter Trebuňa

    2009-03-01

    Full Text Available Dynamic approaches to a management system of the present industrial practice, forcing businesses to address management issues in-house continuous improvement of production and non-production processes. Experience has repeatedly demonstrated the need for a system approach not only in analysis but also in the planning and actual implementation of these processes. Therefore, the contribution is focused on the description of the modeling in industrial practice by a system approach, in order to avoid erroneous application of the decision to the implementation phase, and thus prevent any longer applying methods "attempt - fallacy".

  5. CS model coil experimental log book

    International Nuclear Information System (INIS)

    Nishijima, Gen; Sugimoto, Makoto; Nunoya, Yoshihiko; Wakabayashi, Hiroshi; Tsuji, Hiroshi

    2001-02-01

    Charging test of the ITER CS Model Coil which is the world's largest superconducting pulse coil and the CS Insert Coil had started at April 11, 2000 and had completed at August 18, 2000. In the campaign, total shot numbers were 356 and the size of the data file in the DAS (Data Acquisition System) was over 20 GB. This report is a database that consists of the log list and the log sheets of every shot. One can access the database, make a search, and browse results via Internet (http://1ogwww.naka.jaeri.go.jp). The database will be useful to quick search to choose necessary shots. (author)

  6. Tesla coil theoretical model and experimental verification

    OpenAIRE

    Voitkans, Janis; Voitkans, Arnis

    2014-01-01

    Abstract – In this paper a theoretical model of a Tesla coil operation is proposed. Tesla coil is described as a long line with distributed parameters in a single-wired format, where the line voltage is measured against electrically neutral space. It is shown that equivalent two-wired scheme can be found for a single-wired scheme and already known long line theory can be applied to a Tesla coil. Formulas for calculation of voltage in a Tesla coil by coordinate and calculation of resonance fre...

  7. Experimental photoallergic contact dermatitis: a mouse model

    International Nuclear Information System (INIS)

    Maguire, H.C. Jr.; Kaidbey, K.

    1982-01-01

    We have induced photoallergic contact dermatitis in mice to 3,3',4',5 tetrachlorosalicylanilide (TCSA), chlorpromazine and 6-methylcoumarin. These compounds are known to produce photoallergic contact dermatitis in humans. The photoallergic contact dermatitis reaction in the mouse is immunologically specific viz. mice photosensitized to TCSA react, by photochallenge, to that compound and not to chlorpromazine, and conversely. The reaction requires UVA at both sensitization and challenge. It appears to be T-cell mediated in that it can be passively transferred to syngeneic mice by lymph node cells from actively sensitized mice, the histology of the reactions resembles that of classic allergic contact dermatitis in mice, challenge reactions are seen at 24 but not at 4 hr, and photoallergic contact dermatitis can be induced in B-cell deficient mice. The availability of a mouse model for the study of photo-ACD will facilitate the identification of pertinent control mechanisms and may aid in the management of the disease. It is likely that a bioassay for photoallergens of humans can be based on this mouse model

  8. Three-dimensional FEM model of FBGs in PANDA fibers with experimentally determined model parameters

    Science.gov (United States)

    Lindner, Markus; Hopf, Barbara; Koch, Alexander W.; Roths, Johannes

    2017-04-01

    A 3D-FEM model has been developed to improve the understanding of multi-parameter sensing with Bragg gratings in attached or embedded polarization maintaining fibers. The material properties of the fiber, especially Young's modulus and Poisson's ratio of the fiber's stress applying parts, are crucial for accurate simulations, but are usually not provided by the manufacturers. A methodology is presented to determine the unknown parameters by using experimental characterizations of the fiber and iterative FEM simulations. The resulting 3D-Model is capable of describing the change in birefringence of the free fiber when exposed to longitudinal strain. In future studies the 3D-FEM model will be employed to study the interaction of PANDA fibers with the surrounding materials in which they are embedded.

  9. CS model coil experimental log book

    Energy Technology Data Exchange (ETDEWEB)

    Nishijima, Gen; Sugimoto, Makoto; Nunoya, Yoshihiko; Wakabayashi, Hiroshi; Tsuji, Hiroshi [Japan Atomic Energy Research Inst., Naka, Ibaraki (Japan). Naka Fusion Research Establishment

    2001-02-01

    Charging test of the ITER CS Model Coil which is the world's largest superconducting pulse coil and the CS Insert Coil had started at April 11, 2000 and had completed at August 18, 2000. In the campaign, total shot numbers were 356 and the size of the data file in the DAS (Data Acquisition System) was over 20 GB. This report is a database that consists of the log list and the log sheets of every shot. One can access the database, make a search, and browse results via Internet (http://1ogwww.naka.jaeri.go.jp). The database will be useful to quick search to choose necessary shots. (author)

  10. Microplasticity of MMC. Experimental results and modelling

    International Nuclear Information System (INIS)

    Maire, E.; Lormand, G.; Gobin, P.F.; Fougeres, R.

    1993-01-01

    The microplastic behavior of several MMC is investigated by means of tension and compression tests. This behavior is assymetric : the proportional limit is higher in tension than in compression but the work hardening rate is higher in compression. These differences are analysed in terms of maxium of the Tresca's shear stress at the interface (proportional limit) and of the emission of dislocation loops during the cooling (work hardening rate). On another hand, a model is proposed to calculate the value of the yield stress, describing the composite as a material composed of three phases : inclusion, unaffected matrix and matrix surrounding the inclusion having a gradient in the density of the thermally induced dilocations. (orig.)

  11. Experimental Tests of the Algebraic Cluster Model

    Science.gov (United States)

    Gai, Moshe

    2018-02-01

    The Algebraic Cluster Model (ACM) of Bijker and Iachello that was proposed already in 2000 has been recently applied to 12C and 16O with much success. We review the current status in 12C with the outstanding observation of the ground state rotational band composed of the spin-parity states of: 0+, 2+, 3-, 4± and 5-. The observation of the 4± parity doublet is a characteristic of (tri-atomic) molecular configuration where the three alpha- particles are arranged in an equilateral triangular configuration of a symmetric spinning top. We discuss future measurement with electron scattering, 12C(e,e’) to test the predicted B(Eλ) of the ACM.

  12. Microplasticity of MMC. Experimental results and modelling

    Energy Technology Data Exchange (ETDEWEB)

    Maire, E. (Groupe d' Etude de Metallurgie Physique et de Physique des Materiaux, INSA, 69 Villeurbanne (France)); Lormand, G. (Groupe d' Etude de Metallurgie Physique et de Physique des Materiaux, INSA, 69 Villeurbanne (France)); Gobin, P.F. (Groupe d' Etude de Metallurgie Physique et de Physique des Materiaux, INSA, 69 Villeurbanne (France)); Fougeres, R. (Groupe d' Etude de Metallurgie Physique et de Physique des Materiaux, INSA, 69 Villeurbanne (France))

    1993-11-01

    The microplastic behavior of several MMC is investigated by means of tension and compression tests. This behavior is assymetric : the proportional limit is higher in tension than in compression but the work hardening rate is higher in compression. These differences are analysed in terms of maxium of the Tresca's shear stress at the interface (proportional limit) and of the emission of dislocation loops during the cooling (work hardening rate). On another hand, a model is proposed to calculate the value of the yield stress, describing the composite as a material composed of three phases : inclusion, unaffected matrix and matrix surrounding the inclusion having a gradient in the density of the thermally induced dilocations. (orig.).

  13. Mechanical characterization and constitutive modeling of Mg alloy sheets

    International Nuclear Information System (INIS)

    Mekonen, M. Nebebe; Steglich, D.; Bohlen, J.; Letzig, D.; Mosler, J.

    2012-01-01

    Highlights: ► Material characterization of the Mg alloys AZ31 and ZE10 at elevated temperatures. ► Distortion of the yield locus does not depend on the strain rate. ► Novel constitutive model suitable for the analysis of sheet forming of magnesium. ► Strain-dependent r-values are included within the model. ► The model is thermodynamically consistent and accounts for distortional hardening. - Abstract: In this paper, an experimental mechanical characterization of the magnesium alloys ZE10 and AZ31 is performed and a suitable constitutive model is established. The mechanical characterization is based on uniaxial tensile tests. In order to avoid poor formability at room temperature, the tests were conducted at elevated temperature (200 °C). The uniaxial tensile tests reveal sufficient ductility allowing sheet forming processes at this temperature. The differences in yield stresses and plastic strain ratios (r-values) confirm the anisotropic response of the materials under study. The constitutive model is established so that the characteristic mechanical features observed in magnesium alloys such as anisotropy and compression-tension asymmetry can be accommodated. This model is thermodynamically consistent, incorporates rate effect, is formulated based on finite strain plasticity theory and is applicable in sheet forming simulations of magnesium alloys. More precisely, a model originally proposed by Cazacu and Barlat in 2004 and later modified to account for the evolution of the material anisotropy is rewritten in a thermodynamically consistent framework. The calibrated constitutive model is shown to capture the characteristic mechanical features observed in magnesium alloy sheets.

  14. Experimental investigation on multidisciplinary geophysical characterization of deep underground structure using multi-scale, multi-mode seismic profiling for the evaluation of ground motion and seismic model building

    International Nuclear Information System (INIS)

    Abe, Susumu

    2014-01-01

    Recent advancements in data acquisition and velocity estimation for multi-mode, multiscale seismic exploration were explained along with the basic concept of strategic geophysical surveys for NPP siting assessment. Then, as a case study using this concept, multidisciplinary geophysical characterization results pertaining to the deep underground structure beneath the JNES Kashiwazaki Center were explained in detail. At the site, reflection/refraction surveys and magnetotelluric/gravity surveys were also conducted. It was shown that these surveys can be used complementary because at the upsurge part, where clear images cannot be obtained by reflection/refraction surveys, magnetotelluric /gravity surveys can be used to obtain clear images. (author)

  15. Experimental Hydro-Mechanical Characterization of Full Load Pressure Surge in Francis Turbines

    Science.gov (United States)

    Müller, A.; Favrel, A.; Landry, C.; Yamamoto, K.; Avellan, F.

    2017-04-01

    Full load pressure surge limits the operating range of hydro-electric generating units by causing significant power output swings and by compromising the safety of the plant. It appears during the off-design operation of hydraulic machines, which is increasingly required to regulate the broad integration of volatile renewable energy sources into the existing power network. The underlying causes and governing physical mechanisms of this instability were investigated in the frame of a large European research project and this paper documents the main findings from two experimental campaigns on a reduced scale model of a Francis turbine. The multi-phase flow in the draft tube is characterized by Particle Image Velocimetry, Laser Doppler Velocimetry and high-speed visualizations, along with synchronized measurements of the relevant hydro-mechanical quantities. The final result is a comprehensive overview of how the unsteady draft tube flow and the mechanical torque on the runner shaft behave during one mean period of the pressure oscillation, thus defining the unstable fluid-structure interaction responsible for the power swings. A discussion of the root cause is initiated, based on the state of the art. Finally, the latest results will enable a validation of recent RANS flow simulations used for determining the key parameters of hydro-acoustic stability models.

  16. Multiphysics modelling and experimental validation of high concentration photovoltaic modules

    International Nuclear Information System (INIS)

    Theristis, Marios; Fernández, Eduardo F.; Sumner, Mike; O'Donovan, Tadhg S.

    2017-01-01

    Highlights: • A multiphysics modelling approach for concentrating photovoltaics was developed. • An experimental campaign was conducted to validate the models. • The experimental results were in good agreement with the models. • The multiphysics modelling allows the concentrator’s optimisation. - Abstract: High concentration photovoltaics, equipped with high efficiency multijunction solar cells, have great potential in achieving cost-effective and clean electricity generation at utility scale. Such systems are more complex compared to conventional photovoltaics because of the multiphysics effect that is present. Modelling the power output of such systems is therefore crucial for their further market penetration. Following this line, a multiphysics modelling procedure for high concentration photovoltaics is presented in this work. It combines an open source spectral model, a single diode electrical model and a three-dimensional finite element thermal model. In order to validate the models and the multiphysics modelling procedure against actual data, an outdoor experimental campaign was conducted in Albuquerque, New Mexico using a high concentration photovoltaic monomodule that is thoroughly described in terms of its geometry and materials. The experimental results were in good agreement (within 2.7%) with the predicted maximum power point. This multiphysics approach is relatively more complex when compared to empirical models, but besides the overall performance prediction it can also provide better understanding of the physics involved in the conversion of solar irradiance into electricity. It can therefore be used for the design and optimisation of high concentration photovoltaic modules.

  17. Experimental tests of the standard model

    International Nuclear Information System (INIS)

    Nodulman, L.

    1998-01-01

    The title implies an impossibly broad field, as the Standard Model includes the fermion matter states, as well as the forces and fields of SU(3) x SU(2) x U(1). For practical purposes, I will confine myself to electroweak unification, as discussed in the lectures of M. Herrero. Quarks and mixing were discussed in the lectures of R. Aleksan, and leptons and mixing were discussed in the lectures of K. Nakamura. I will essentially assume universality, that is flavor independence, rather than discussing tests of it. I will not pursue tests of QED beyond noting the consistency and precision of measurements of α EM in various processes including the Lamb shift, the anomalous magnetic moment (g-2) of the electron, and the quantum Hall effect. The fantastic precision and agreement of these predictions and measurements is something that convinces people that there may be something to this science enterprise. Also impressive is the success of the ''Universal Fermi Interaction'' description of beta decay processes, or in more modern parlance, weak charged current interactions. With one coupling constant G F , most precisely determined in muon decay, a huge number of nuclear instabilities are described. The slightly slow rate for neutron beta decay was one of the initial pieces of evidence for Cabbibo mixing, now generalized so that all charged current decays of any flavor are covered

  18. Removal of Cr(III ions from salt solution by nanofiltration: experimental and modelling analysis

    Directory of Open Access Journals (Sweden)

    Kowalik-Klimczak Anna

    2016-09-01

    Full Text Available The aim of this study was experimental and modelling analysis of the nanofiltration process used for the removal of chromium(III ions from salt solution characterized by low pH. The experimental results were interpreted with Donnan and Steric Partitioning Pore (DSP model based on the extended Nernst-Planck equation. In this model, one of the main parameters, describing retention of ions by the membrane, is pore dielectric constant. In this work, it was identified for various process pressures and feed compositions. The obtained results showed the satisfactory agreement between the experimental and modelling data. It means that the DSP model may be helpful for the monitoring of nanofiltration process applied for treatment of chromium tannery wastewater.

  19. Orientation sensitive deformation in Zr alloys: experimental and modeling studies

    International Nuclear Information System (INIS)

    Srivastava, D.; Keskar, N.; Manikrishna, K.V.; Dey, G.K.; Jha, S.K.; Saibaba, N.

    2016-01-01

    Zirconium alloys are used for fuel cladding and other structural components in pressurised heavy water nuclear reactors (PHWR's). Currently there is a lot of interest in developing alloys for structural components for higher temperature reactor operation. There is also need for development of cladding material with better corrosion and mechanical property of cladding material for higher and extended burn up applications. The performance of the cladding material is primarily influenced by the microstructural features of the material such as constituent phases their morphology, precipitates characteristics, nature of defects etc. Therefore, the microstructure is tailored as per the performance requirement by through controlled additions of alloying elements, thermo-mechanical- treatments. In order to obtain the desired microstructure, it is important to know the deformation behaviour of the material. Orientation dependent deformation behavior was studied in Zr using a combination of experimental and modeling (both discrete and atomistic dislocation dynamics) methods. Under the conditions of plane strain deformation, it was observed that single phase Zr, had significant extent of deformation heterogeneity based on local orientations. Discrete dislocation dynamics simulations incorporating multi slip systems had captured the orientation sensitive deformation. MD dislocations on the other hand brought the fundamental difference in various crystallographic orientations in determining the nucleating stress for the dislocations. The deformed structure has been characterized using X-ray, electron and neutron diffraction techniques. The various operating deformation mechanism will be discussed in this presentation. (author)

  20. Spatial Stochastic Point Models for Reservoir Characterization

    Energy Technology Data Exchange (ETDEWEB)

    Syversveen, Anne Randi

    1997-12-31

    The main part of this thesis discusses stochastic modelling of geology in petroleum reservoirs. A marked point model is defined for objects against a background in a two-dimensional vertical cross section of the reservoir. The model handles conditioning on observations from more than one well for each object and contains interaction between objects, and the objects have the correct length distribution when penetrated by wells. The model is developed in a Bayesian setting. The model and the simulation algorithm are demonstrated by means of an example with simulated data. The thesis also deals with object recognition in image analysis, in a Bayesian framework, and with a special type of spatial Cox processes called log-Gaussian Cox processes. In these processes, the logarithm of the intensity function is a Gaussian process. The class of log-Gaussian Cox processes provides flexible models for clustering. The distribution of such a process is completely characterized by the intensity and the pair correlation function of the Cox process. 170 refs., 37 figs., 5 tabs.

  1. Mutant mice: experimental organisms as materialised models in biomedicine.

    Science.gov (United States)

    Huber, Lara; Keuck, Lara K

    2013-09-01

    Animal models have received particular attention as key examples of material models. In this paper, we argue that the specificities of establishing animal models-acknowledging their status as living beings and as epistemological tools-necessitate a more complex account of animal models as materialised models. This becomes particularly evident in animal-based models of diseases that only occur in humans: in these cases, the representational relation between animal model and human patient needs to be generated and validated. The first part of this paper presents an account of how disease-specific animal models are established by drawing on the example of transgenic mice models for Alzheimer's disease. We will introduce an account of validation that involves a three-fold process including (1) from human being to experimental organism; (2) from experimental organism to animal model; and (3) from animal model to human patient. This process draws upon clinical relevance as much as scientific practices and results in disease-specific, yet incomplete, animal models. The second part of this paper argues that the incompleteness of models can be described in terms of multi-level abstractions. We qualify this notion by pointing to different experimental techniques and targets of modelling, which give rise to a plurality of models for a specific disease. Copyright © 2013 Elsevier Ltd. All rights reserved.

  2. Experimental characterization of dielectric-loaded plasmonic waveguide-racetrack resonators at near-infrared wavelengths

    DEFF Research Database (Denmark)

    Garcia, Cesar; Coello, Victor; Han, Zhanghua

    2012-01-01

    Dielectric-loaded plasmonic waveguide-racetrack resonators (WRTRs) were designed and fabricated for operating at near-infrared wavelengths (750–850 nm) and characterized using leakage-radiation microscopy. The transmission spectra of the WRTRs are found experimentally and compared to the calculat...

  3. Morphofunctional analysis of experimental model of esophageal achalasia in rats.

    Science.gov (United States)

    Sabirov, A G; Raginov, I S; Burmistrov, M V; Chelyshev, Y A; Khasanov, R Sh; Moroshek, A A; Grigoriev, P N; Zefirov, A L; Mukhamedyarov, M A

    2010-10-01

    We carried out a detailed analysis of rat model of esophageal achalasia previously developed by us. Manifest morphological and functional disorders were observed in experimental achalasia: hyperplasia of the squamous epithelium, reduced number of nerve fibers, excessive growth of fibrous connective tissue in the esophageal wall, high contractile activity of the lower esophageal sphincter, and reduced motility of the longitudinal muscle layer. Changes in rat esophagus observed in experimental achalasia largely correlate with those in esophageal achalasia in humans. Hence, our experimental model can be used for the development of new methods of disease treatment.

  4. The experimental and shell model approach to 100Sn

    International Nuclear Information System (INIS)

    Grawe, H.; Maier, K.H.; Fitzgerald, J.B.; Heese, J.; Spohr, K.; Schubart, R.; Gorska, M.; Rejmund, M.

    1995-01-01

    The present status of experimental approach to 100 Sn and its shell model structure is given. New developments in experimental techniques, such as low background isomer spectroscopy and charged particle detection in 4π are surveyed. Based on recent experimental data shell model calculations are used to predict the structure of the single- and two-nucleon neighbours of 100 Sn. The results are compared to the systematic of Coulomb energies and spin-orbit splitting and discussed with respect to future experiments. (author). 51 refs, 11 figs, 1 tab

  5. Characterization of a porcine model of chronic superficial varicose veins.

    Science.gov (United States)

    Jones, Gregory T; Grant, Mark W; Thomson, Ian A; Hill, B Geraldine; van Rij, André M

    2009-06-01

    Previous animal models of venous disease, while inducing venous hypertension and valvular insufficiency, do not produce superficial varicose veins. In this study, we aimed to develop and characterize a pig-based model of superficial varicose veins. Right femoral arteriovenous fistulae (AVF) were surgically fashioned in young adult pigs. Animals were examined at postoperative times up to 15 weeks to determine the development of varicose veins and measurement of both blood pressure and flow velocities within the superficial thigh veins. Histology and vascular corrosion casts were used to characterize the resulting structural venous alterations. Porcine pathophysiological features were compared with those of human primary superficial varicose veins. Gross superficial varicosities developed over the ipsilateral medial thigh region after an initial lag period of 1-2 weeks. Veins demonstrated retrograde filling with valvular incompetence, and a moderate, non-pulsatile, venous hypertension, which was altered by changes in posture and Valsalva. Venous blood flow velocities were elevated to 15-30 cm/s in varicose veins. Structurally, pig varicose veins were enlarged, tortuous, had valvular degeneration, and regions of focal medial atrophy with or without overlying intimal thickening. The superficial varicose veins, which developed within this model, have a pathophysiology that is consistent with that observed in humans. The porcine femoral AVF model is proposed as a suitable experimental model to evaluate the pathobiology of superficial venous disease. It may also be suitable for the evaluation of treatment interventions including drug therapy.

  6. An experimental model to mimic the mechanical behavior of a scaffold in a cartilage defect

    OpenAIRE

    VIKINGSSON, LINE KARINA ALVA

    2015-01-01

    [EN] Abstract The main purpose of this thesis is the design and characterization of an experimental articular cartilage model. The in vitro model is composed of a macro and micro- porous Polycaprolactone scaffold with a Poly(Vinyl Alcohol) filling. The scaffold/hydrogel construct has been subjected to repeating number of freezing and thawing cycles in order to crosslink the hydrogel inside the scaffold's pores. The Poly(Vinyl Alcohol) resembles the growing cartilaginous tissue inside the ...

  7. Endogenous opioid antagonism in physiological experimental pain models

    DEFF Research Database (Denmark)

    Werner, Mads U; Pereira, Manuel P; Andersen, Lars Peter H

    2015-01-01

    hyperalgesia models (6 studies), 'pain' models (25 studies), summation models (2 studies), nociceptive reflex models (3 studies) and miscellaneous models (2 studies). A consistent reversal of analgesia by a MOR-antagonist was demonstrated in 10 of the 25 ITP-studies, including stress-induced analgesia and r...... ratings, threshold assessments and somatosensory evoked potentials (SSEP), did not appear consistent in 28 out of 32 'pain' model studies. In conclusion, only in 2 experimental human pain models, i.e., stress-induced analgesia and rTMS, administration of MOR-antagonist demonstrated a consistent effect......Opioid antagonists are pharmacological tools applied as an indirect measure to detect activation of the endogenous opioid system (EOS) in experimental pain models. The objective of this systematic review was to examine the effect of mu-opioid-receptor (MOR) antagonists in placebo-controlled, double...

  8. Characterization and modeling of the heat source

    Energy Technology Data Exchange (ETDEWEB)

    Glickstein, S.S.; Friedman, E.

    1993-10-01

    A description of the input energy source is basic to any numerical modeling formulation designed to predict the outcome of the welding process. The source is fundamental and unique to each joining process. The resultant output of any numerical model will be affected by the initial description of both the magnitude and distribution of the input energy of the heat source. Thus, calculated weld shape, residual stresses, weld distortion, cooling rates, metallurgical structure, material changes due to excessive temperatures and potential weld defects are all influenced by the initial characterization of the heat source. Understandings of both the physics and the mathematical formulation of these sources are essential for describing the input energy distribution. This section provides a brief review of the physical phenomena that influence the input energy distributions and discusses several different models of heat sources that have been used in simulating arc welding, high energy density welding and resistance welding processes. Both simplified and detailed models of the heat source are discussed.

  9. Effective dielectric mixture model for characterization of diesel contaminated soil

    International Nuclear Information System (INIS)

    Al-Mattarneh, H.M.A.

    2007-01-01

    Human exposure to contaminated soil by diesel isomers can have serious health consequences like neurological diseases or cancer. The potential of dielectric measuring techniques for electromagnetic characterization of contaminated soils was investigated in this paper. The purpose of the research was to develop an empirical dielectric mixture model for soil hydrocarbon contamination application. The paper described the basic theory and elaborated in dielectric mixture theory. The analytical and empirical models were explained in simple algebraic formulas. The experimental study was then described with reference to materials, properties and experimental results. The results of the analytical models were also mathematically explained. The proposed semi-empirical model was also presented. According to the result of the electromagnetic properties of dry soil contaminated with diesel, the diesel presence had no significant effect on the electromagnetic properties of dry soil. It was concluded that diesel had no contribution to the soil electrical conductivity, which confirmed the nonconductive character of diesel. The results of diesel-contaminated soil at saturation condition indicated that both dielectric constant and loss factors of soil were decreased with increasing diesel content. 15 refs., 2 tabs., 9 figs

  10. An investigation on characterizing dense coal-water slurry with ultrasound: theoretical and experimental method

    Energy Technology Data Exchange (ETDEWEB)

    Xue, M.H.; Su, M.X.; Dong, L.L.; Shang, Z.T.; Cai, X.S. [Shanghai University of Science & Technology, Shanghai (China)

    2010-07-01

    Particle size distribution and concentration in particulate two-phase flow are important parameters in a wide variety of industrial areas. For the purpose of online characterization in dense coal-water slurries, ultrasonic methods have many advantages such as avoiding dilution, the capability for being used in real time, and noninvasive testing, while light-based techniques are not capable of providing information because optical methods often require the slurry to be diluted. In this article, the modified Urick equation including temperature modification, which can be used to determine the concentration by means of the measurement of ultrasonic velocity in a coal-water slurry, is evaluated on the basis of theoretical analysis and experimental study. A combination of the coupled-phase model and the Bouguer-Lambert-Beer law is employed in this work, and the attenuation spectrum is measured within the frequency region from 3 to 12 MHz. Particle size distributions of the coal-water slurry at different volume fractions are obtained with the optimum regularization technique. Therefore, the ultrasonic technique presented in this work brings the possibility of using ultrasound for online measurements of dense slurries.

  11. Review for 'Nattoh' model and experimental findings during cold fusion

    International Nuclear Information System (INIS)

    Matsumoto, Takaaki

    1993-01-01

    A review is described for the Nattoh model that provides the framework of the mechanisms of cold fusion. The model classifies the reactions into two categories: fundamental and associated reactions. The former involves the new 'hydrogen-catalyzed' fusion reaction and the chain-reactions of hydrogens. And extremely exciting physics are involved in the latter. Furthermore experimental findings are described. (author)

  12. Water retention behaviour of compacted bentonites: experimental observations and constitutive model

    Directory of Open Access Journals (Sweden)

    Dieudonne Anne-Catherine

    2016-01-01

    Full Text Available Bentonite-based materials are studied as potential barriers for the geological disposal of radioactive waste. In this context, the hydro-mechanical behaviour of the engineered barrier is first characterized by free swelling conditions followed by constant volume conditions. This paper presents an experimental study conducted in order to characterize the water retention behaviour of a compacted MX-80 bentonite/sand mixture. Then, based on observations of the material double structure and the water retention mechanisms in compacted bentonites, a new water retention model is proposed. The model considers adsorbed water in the microstructure and capillary water in the aggregate-porosity. The model is calibrated and validated against the experimental data. It is used for better understanding competing effects between volume change and water uptake observed during hydration under free swelling conditions.

  13. Experimental study and modeling of a novel magnetorheological elastomer isolator

    International Nuclear Information System (INIS)

    Yang, Jian; Li, Weihua; Sun, Shuaishuai; Du, Haiping; Li, Yancheng; Li, Jianchun; Deng, H X

    2013-01-01

    This paper reports an experimental setup aiming at evaluating the performance of a newly designed magnetorheological elastomer (MRE) seismic isolator. As a further effort to explore the field-dependent stiffness/damping properties of the MRE isolator, a series of experimental testing were conducted. Based upon the analysis of the experimental responses and the characteristics of the MRE isolator, a new model that is capable of reproducing the unique MRE isolator dynamics behaviors is proposed. The validation results verify the model’s effectiveness to portray the MRE isolator. A study on the field-dependent parameters is then provided to make the model valid with fluctuating magnetic fields. To fully explore the mechanism of the proposed model, an investigation relating the dependence of the proposed model on every parameter is carried out. (technical note)

  14. Experimental models of hepatotoxicity related to acute liver failure

    Energy Technology Data Exchange (ETDEWEB)

    Maes, Michaël [Department of In Vitro Toxicology and Dermato-Cosmetology, Vrije Universiteit Brussel, Brussels (Belgium); Vinken, Mathieu, E-mail: mvinken@vub.ac.be [Department of In Vitro Toxicology and Dermato-Cosmetology, Vrije Universiteit Brussel, Brussels (Belgium); Jaeschke, Hartmut [Department of Pharmacology, Toxicology and Therapeutics, University of Kansas Medical Center, Kansas City (United States)

    2016-01-01

    Acute liver failure can be the consequence of various etiologies, with most cases arising from drug-induced hepatotoxicity in Western countries. Despite advances in this field, the management of acute liver failure continues to be one of the most challenging problems in clinical medicine. The availability of adequate experimental models is of crucial importance to provide a better understanding of this condition and to allow identification of novel drug targets, testing the efficacy of new therapeutic interventions and acting as models for assessing mechanisms of toxicity. Experimental models of hepatotoxicity related to acute liver failure rely on surgical procedures, chemical exposure or viral infection. Each of these models has a number of strengths and weaknesses. This paper specifically reviews commonly used chemical in vivo and in vitro models of hepatotoxicity associated with acute liver failure. - Highlights: • The murine APAP model is very close to what is observed in patients. • The Gal/ET model is useful to study TNFα-mediated apoptotic signaling mechanisms. • Fas receptor activation is an effective model of apoptosis and secondary necrosis. • The ConA model is a relevant model of auto-immune hepatitis and viral hepatitis. • Multiple time point evaluation needed in experimental models of acute liver injury.

  15. Experimental Characterization of the Energy Absorption of Functionally Graded Foam Filled Tubes Under Axial Crushing Loads

    Science.gov (United States)

    Ebrahimi, Saeed; Vahdatazad, Nader; Liaghat, Gholamhossein

    2018-03-01

    This paper deals with the energy absorption characterization of functionally graded foam (FGF) filled tubes under axial crushing loads by experimental method. The FGF tubes are filled axially by gradient layers of polyurethane foams with different densities. The mechanical properties of the polyurethane foams are firstly obtained from axial compressive tests. Then, the quasi-static compressive tests are carried out for empty tubes, uniform foam filled tubes and FGF filled tubes. Before to present the experimental test results, a nonlinear FEM simulation of the FGF filled tube is carried out in ABAQUS software to gain more insight into the crush deformation patterns, as well as the energy absorption capability of the FGF filled tube. A good agreement between the experimental and simulation results is observed. Finally, the results of experimental test show that an FGF filled tube has excellent energy absorption capacity compared to the ordinary uniform foam-filled tube with the same weight.

  16. Using an experimental model for the study of therapeutic touch.

    Science.gov (United States)

    dos Santos, Daniella Soares; Marta, Ilda Estéfani Ribeiro; Cárnio, Evelin Capellari; de Quadros, Andreza Urba; Cunha, Thiago Mattar; de Carvalho, Emilia Campos

    2013-02-01

    to verify whether the Paw Edema Model can be used in investigations about the effects of Therapeutic Touch on inflammation by measuring the variables pain, edema and neutrophil migration. this is a pilot and experimental study, involving ten male mice of the same genetic strain and divided into experimental and control group, submitted to the chemical induction of local inflammation in the right back paw. The experimental group received a daily administration of Therapeutic Touch for 15 minutes during three days. the data showed statistically significant differences in the nociceptive threshold and in the paw circumference of the animals from the experimental group on the second day of the experiment. the experiment model involving animals can contribute to study the effects of Therapeutic Touch on inflammation, and adjustments are suggested in the treatment duration, number of sessions and experiment duration.

  17. Development of a fault test experimental facility model using Matlab

    Energy Technology Data Exchange (ETDEWEB)

    Pereira, Iraci Martinez; Moraes, Davi Almeida, E-mail: martinez@ipen.br, E-mail: dmoraes@dk8.com.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2015-07-01

    The Fault Test Experimental Facility was developed to simulate a PWR nuclear power plant and is instrumented with temperature, level and pressure sensors. The Fault Test Experimental Facility can be operated to generate normal and fault data, and these failures can be added initially small, and their magnitude being increasing gradually. This work presents the Fault Test Experimental Facility model developed using the Matlab GUIDE (Graphical User Interface Development Environment) toolbox that consists of a set of functions designed to create interfaces in an easy and fast way. The system model is based on the mass and energy inventory balance equations. Physical as well as operational aspects are taken into consideration. The interface layout looks like a process flowchart and the user can set the input variables. Besides the normal operation conditions, there is the possibility to choose a faulty variable from a list. The program also allows the user to set the noise level for the input variables. Using the model, data were generated for different operational conditions, both under normal and fault conditions with different noise levels added to the input variables. Data generated by the model will be compared with Fault Test Experimental Facility data. The Fault Test Experimental Facility theoretical model results will be used for the development of a Monitoring and Fault Detection System. (author)

  18. Development of a fault test experimental facility model using Matlab

    International Nuclear Information System (INIS)

    Pereira, Iraci Martinez; Moraes, Davi Almeida

    2015-01-01

    The Fault Test Experimental Facility was developed to simulate a PWR nuclear power plant and is instrumented with temperature, level and pressure sensors. The Fault Test Experimental Facility can be operated to generate normal and fault data, and these failures can be added initially small, and their magnitude being increasing gradually. This work presents the Fault Test Experimental Facility model developed using the Matlab GUIDE (Graphical User Interface Development Environment) toolbox that consists of a set of functions designed to create interfaces in an easy and fast way. The system model is based on the mass and energy inventory balance equations. Physical as well as operational aspects are taken into consideration. The interface layout looks like a process flowchart and the user can set the input variables. Besides the normal operation conditions, there is the possibility to choose a faulty variable from a list. The program also allows the user to set the noise level for the input variables. Using the model, data were generated for different operational conditions, both under normal and fault conditions with different noise levels added to the input variables. Data generated by the model will be compared with Fault Test Experimental Facility data. The Fault Test Experimental Facility theoretical model results will be used for the development of a Monitoring and Fault Detection System. (author)

  19. Functional Characterization of a Porcine Emphysema Model

    DEFF Research Database (Denmark)

    Bruun, Camilla Sichlau; Jensen, Louise Kruse; Leifsson, Páll Skuli

    2013-01-01

    Lung emphysema is a central feature of chronic obstructive pulmonary disease (COPD), a frequent human disease worldwide. Cigarette smoking is the major cause of COPD, but genetic predisposition seems to be an important factor. Mutations in surfactant protein genes have been linked to COPD...... phenotypes in humans. Also, the catalytic activities of metalloproteinases (MMPs) are central in the pathogenesis of emphysema/COPD. Especially MMP9, but also MMP2, MMP7, and MMP12 seem to be involved in human emphysema. MMP12−/− mice are protected from smoke-induced emphysema. ITGB6−/− mice spontaneously...... develop age-related lung emphysema due to lack of ITGB6-TGF-β1 regulation of the MMP12 expression.A mutated pig phenotype characterized by age-related lung emphysema and resembling the ITGB6−/− mouse has been described previously. To investigate the emphysema pathogenesis in this pig model, we examined...

  20. Teaching Photovoltaic Array Modelling and Characterization Using a Graphical User Interface and a Flash Solar Simulator

    DEFF Research Database (Denmark)

    Spataru, Sergiu; Sera, Dezso; Kerekes, Tamas

    2012-01-01

    This paper presents a set of laboratory tools aimed to support students with various backgrounds (no programming) to understand photovoltaic array modelling and characterization techniques. A graphical user interface (GUI) has been developed in Matlab, for modelling PV arrays and characterizing...... the effect of different types of parameters and operating conditions, on the current-voltage and power-voltage curves. The GUI is supported by experimental investigation and validation on PV module level, with the help of an indoor flash solar simulator....

  1. Experimental and numerical characterization of scalable cellulose nano-fiber composite

    Science.gov (United States)

    Barari, Bamdad

    Fiber-reinforced polymer composites have been used in recent years as an alternative to the conventional materials because of their low weight, high mechanical properties and low processing temperatures. Most polymer composites are traditionally made using reinforcing fibers such as carbon or glass fibers. However, there has been recent interest in making these reinforcing fibers from natural resources. The plant-derived cellulose nano-fibers (CNF) are a material with remarkable mechanical properties at the nano-scale that are much superior to the mechanical properties of the traditional natural fibers (such as jute, hemp, kenaf, etc) used in the natural-fiber based polymer composites. Because CNF is bio-based and biodegradable, it is an attractive 'green' alternative for use in automotive, aerospace, and other engineering applications. However, efforts to produce CNF based nano-composites, with successful scaling-up of the remarkable nanoscale properties of CNF, have not met with much success and form an active area of research. The main goals of this research are to characterize the scalable CNF based nano composites using experimental methods and to develop effective models for flow of polymeric resin in the CNF-based porous media used during the proposed manufacture of CNF nano-composites. In the CNF composite characterization section, scalable isotropic and anisotropic CNF composites were made from a porous CNF preforms created using a freeze drying process. Formation of the fibers during freeze-drying process can change the micro skeleton of the final preform structure as non-aligned or isotropic and aligned or anisotropic CNF. Liquid Composite Molding (LCM) processes form a set of liquid molding technologies that are used quite commonly for making the conventional polymer composites. An improvised vacuum-driven LCM process was used to make the CNF-based nanocomposites from CNF preforms using a 'green' epoxy resin with high bio-content. Under the topic of

  2. Resolving Nuclear Reactor Lifetime Extension Questions: A Combined Multiscale Modeling and Positron Characterization approach

    International Nuclear Information System (INIS)

    Wirth, B; Asoka-Kumar, P; Denison, A; Glade, S; Howell, R; Marian, J; Odette, G; Sterne, P

    2004-01-01

    The objective of this work is to determine the chemical composition of nanometer precipitates responsible for irradiation hardening and embrittlement of reactor pressure vessel steels, which threaten to limit the operating lifetime of nuclear power plants worldwide. The scientific approach incorporates computational multiscale modeling of radiation damage and microstructural evolution in Fe-Cu-Ni-Mn alloys, and experimental characterization by positron annihilation spectroscopy and small angle neutron scattering. The modeling and experimental results are

  3. Investigation of wax precipitation in crude oil: Experimental and modeling

    Directory of Open Access Journals (Sweden)

    Taraneh Jafari Behbahani

    2015-09-01

    Full Text Available In this work, a series of experiments were carried to investigation of rheological behavior of crude oil using waxy crude oil sample in the absence/presence of flow improver such as ethylene-vinyl acetate copolymer. The rheological data covered the temperature range of 5–30 °C. The results indicated that the performance of flow improver was dependent on its molecular weight. Addition of small quantities of flow improver, can improve viscosity and pour point of crude oil. Also, an Artificial Neural Network (ANN model using Multi-Layer Perceptron (MLP topology has been developed to account wax appearance temperature and the amount of precipitated wax and the model was verified using experimental data given in this work and reported in the literature. In order to compare the performance of the proposed model based on Artificial Neural Network, the wax precipitation experimental data at different temperatures were predicted using solid solution model and multi-solid phase model. The results showed that the developed model based on Artificial Neural Network can predict more accurately the wax precipitation experimental data in comparison to the previous models such as solid solution and multi-solid phase model with AADs less than 0.5%. Furthermore, the number of parameters required for the Artificial Neural Network (ANN model is less than the studied thermodynamic models.

  4. Behavioral characterization of mouse models of neuroferritinopathy.

    Directory of Open Access Journals (Sweden)

    Sara Capoccia

    Full Text Available Ferritin is the main intracellular protein of iron storage with a central role in the regulation of iron metabolism and detoxification. Nucleotide insertions in the last exon of the ferritin light chain cause a neurodegenerative disease known as Neuroferritinopathy, characterized by iron deposition in the brain, particularly in the cerebellum, basal ganglia and motor cortex. The disease progresses relentlessly, leading to dystonia, chorea, motor disability and neuropsychiatry features. The characterization of a good animal model is required to compare and contrast specific features with the human disease, in order to gain new insights on the consequences of chronic iron overload on brain function and behavior. To this aim we studied an animal model expressing the pathogenic human FTL mutant 498InsTC under the phosphoglycerate kinase (PGK promoter. Transgenic (Tg mice showed strong accumulation of the mutated protein in the brain, which increased with age, and this was accompanied by brain accumulation of ferritin/iron bodies, the main pathologic hallmark of human neuroferritinopathy. Tg-mice were tested throughout development and aging at 2-, 8- and 18-months for motor coordination and balance (Beam Walking and Footprint tests. The Tg-mice showed a significant decrease in motor coordination at 8 and 18 months of age, with a shorter latency to fall and abnormal gait. Furthermore, one group of aged naïve subjects was challenged with two herbicides (Paraquat and Maneb known to cause oxidative damage. The treatment led to a paradoxical increase in behavioral activation in the transgenic mice, suggestive of altered functioning of the dopaminergic system. Overall, data indicate that mice carrying the pathogenic FTL498InsTC mutation show motor deficits with a developmental profile suggestive of a progressive pathology, as in the human disease. These mice could be a powerful tool to study the neurodegenerative mechanisms leading to the disease and help

  5. Behavioral characterization of mouse models of neuroferritinopathy.

    Science.gov (United States)

    Capoccia, Sara; Maccarinelli, Federica; Buffoli, Barbara; Rodella, Luigi F; Cremona, Ottavio; Arosio, Paolo; Cirulli, Francesca

    2015-01-01

    Ferritin is the main intracellular protein of iron storage with a central role in the regulation of iron metabolism and detoxification. Nucleotide insertions in the last exon of the ferritin light chain cause a neurodegenerative disease known as Neuroferritinopathy, characterized by iron deposition in the brain, particularly in the cerebellum, basal ganglia and motor cortex. The disease progresses relentlessly, leading to dystonia, chorea, motor disability and neuropsychiatry features. The characterization of a good animal model is required to compare and contrast specific features with the human disease, in order to gain new insights on the consequences of chronic iron overload on brain function and behavior. To this aim we studied an animal model expressing the pathogenic human FTL mutant 498InsTC under the phosphoglycerate kinase (PGK) promoter. Transgenic (Tg) mice showed strong accumulation of the mutated protein in the brain, which increased with age, and this was accompanied by brain accumulation of ferritin/iron bodies, the main pathologic hallmark of human neuroferritinopathy. Tg-mice were tested throughout development and aging at 2-, 8- and 18-months for motor coordination and balance (Beam Walking and Footprint tests). The Tg-mice showed a significant decrease in motor coordination at 8 and 18 months of age, with a shorter latency to fall and abnormal gait. Furthermore, one group of aged naïve subjects was challenged with two herbicides (Paraquat and Maneb) known to cause oxidative damage. The treatment led to a paradoxical increase in behavioral activation in the transgenic mice, suggestive of altered functioning of the dopaminergic system. Overall, data indicate that mice carrying the pathogenic FTL498InsTC mutation show motor deficits with a developmental profile suggestive of a progressive pathology, as in the human disease. These mice could be a powerful tool to study the neurodegenerative mechanisms leading to the disease and help developing

  6. Optimality models in the age of experimental evolution and genomics

    OpenAIRE

    Bull, J. J.; Wang, I.-N.

    2010-01-01

    Optimality models have been used to predict evolution of many properties of organisms. They typically neglect genetic details, whether by necessity or design. This omission is a common source of criticism, and although this limitation of optimality is widely acknowledged, it has mostly been defended rather than evaluated for its impact. Experimental adaptation of model organisms provides a new arena for testing optimality models and for simultaneously integrating genetics. First, an experimen...

  7. Confrontation of thermoluminescence models in lithium fluoride with experimental data

    International Nuclear Information System (INIS)

    Niewiadomski, T.

    1976-12-01

    The thermoluminescent properties of lithium fluoride depend on numerous factors and are much more complex than those of other phosphors. The so far developed fragmentary models are meant to explain the relationships between crystal defect structure and the processes involved in TL. An attempt has been made to compare these models with the veryfied experimental data and to point out the observations which are inconsistant with the models. (author)

  8. Experimental Testing Procedures and Dynamic Model Validation for Vanadium Redox Flow Battery Storage System

    DEFF Research Database (Denmark)

    Baccino, Francesco; Marinelli, Mattia; Nørgård, Per Bromand

    2013-01-01

    The paper aims at characterizing the electrochemical and thermal parameters of a 15 kW/320 kWh vanadium redox flow battery (VRB) installed in the SYSLAB test facility of the DTU Risø Campus and experimentally validating the proposed dynamic model realized in Matlab-Simulink. The adopted testing...... efficiency of the battery system. The test procedure has general validity and could also be used for other storage technologies. The storage model proposed and described is suitable for electrical studies and can represent a general model in terms of validity. Finally, the model simulation outputs...

  9. The characterization of multilayers analyzers: Models and measurements

    International Nuclear Information System (INIS)

    Henke, B.L.; Vejio, J.Y.; Tackaberry, R.E.; Yamada, H.T.

    1985-01-01

    A procedure is described for the detailed characterization of multilayer analyzers which can be effectively applied to their design, optimization and application for absolute x-ray spectrometry. An accurate analytical model has been developed that is based upon a simple modification of the dynamical Darwin-Prins theory to extend its application to finite multilayer systems. Its equivalence to the optical E and M solution of the Fresnel equations at each interface is demonstrated by detailed calculation comparisons for the reflectivity of a multilayer throughout the angular range of incidence of 0 to 90 0 . A special spectrograph and experimental method is described for the measurement of the absolute reflectivity characteristics of the multilayer. The experimental measurements at three photon energies in the 100-200 eV region are fit by the analytical modified Darwin-Prins equation (MDP) for I(θ), generating a detailed characterization of two ''state of the art'' multilayers, a sputtered tungsten-carbon of 2d ≅ 70 A and a molecular lead separate of 2d ≅ 100 A. The fitting parameters that are determined in this procedure are applied to help establish the structural characteristics of the particular multilayer

  10. Experimental Characterization of Aluminum-Based Hybrid Composites Obtained Through Powder Metallurgy

    Science.gov (United States)

    Marcu, D. F.; Buzatu, M.; Ghica, V. G.; Petrescu, M. I.; Popescu, G.; Niculescu, F.; Iacob, G.

    2018-06-01

    The paper presents some experimental results concerning fabrication through powder metallurgy (P/M) of aluminum-based hybrid composites - Al/Al2O3/Gr. In order to understand the mechanisms that occur during the P/M processes of obtaining Al/Al2O3/Gr composite, we correlated the physical characteristics with their micro-structural characteristics. The characterization was performed using analysis techniques specific for P/M process, SEM-EDS and XRD analyses. Micro-structural characterization of the composites has revealed fairly uniform distribution this resulting in good properties of the final composite material.

  11. Comparison of experimental techniques for characterization of through-thickness texture variations

    DEFF Research Database (Denmark)

    Mishin, Oleg; Lauridsen, E.M.; Krieger Lassen, N.C.

    1999-01-01

    For the investigation of through-thickness texture gradients, a number of layers in rolled plates and sheets are inspected. Crystallographic textures in different layers can be characterized using several techniques. In the present work, traditional low-energy X-ray diffraction, the electron...... backscattering pattern technique in the scanning electron microscope and a novel technique which involves high energy synchrotron radiation are used for characterization of through-thickness texture variations in commercial purity cold-rolled aluminium. Important experimental aspects of these three techniques...

  12. Experimental dynamical characterization of five autonomous chaotic oscillators with tunable series resistance

    Energy Technology Data Exchange (ETDEWEB)

    Minati, Ludovico, E-mail: lminati@ieee.org, E-mail: ludovico.minati@unitn.it [MR-Lab, Center for Mind/Brain Science, University of Trento, Trento, Italy and Scientific Department, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan (Italy)

    2014-09-01

    In this paper, an experimental characterization of the dynamical properties of five autonomous chaotic oscillators, based on bipolar-junction transistors and obtained de-novo through a genetic algorithm in a previous study, is presented. In these circuits, a variable resistor connected in series to the DC voltage source acts as control parameter, for a range of which the largest Lyapunov exponent, correlation dimension, approximate entropy, and amplitude variance asymmetry are calculated, alongside bifurcation diagrams and spectrograms. Numerical simulations are compared to experimental measurements. The oscillators can generate a considerable variety of regular and chaotic sine-like and spike-like signals.

  13. Experimental Validation of a Dynamic Model for Lightweight Robots

    Directory of Open Access Journals (Sweden)

    Alessandro Gasparetto

    2013-03-01

    Full Text Available Nowadays, one of the main topics in robotics research is dynamic performance improvement by means of a lightening of the overall system structure. The effective motion and control of these lightweight robotic systems occurs with the use of suitable motion planning and control process. In order to do so, model-based approaches can be adopted by exploiting accurate dynamic models that take into account the inertial and elastic terms that are usually neglected in a heavy rigid link configuration. In this paper, an effective method for modelling spatial lightweight industrial robots based on an Equivalent Rigid Link System approach is considered from an experimental validation perspective. A dynamic simulator implementing the formulation is used and an experimental test-bench is set-up. Experimental tests are carried out with a benchmark L-shape mechanism.

  14. Multifunctional multiscale composites: Processing, modeling and characterization

    Science.gov (United States)

    Qiu, Jingjing

    Carbon nanotubes (CNTs) demonstrate extraordinary properties and show great promise in enhancing out-of-plane properties of traditional polymer/fiber composites and enabling functionality. However, current manufacturing challenges hinder the realization of their potential. In the dissertation research, both experimental and computational efforts have been conducted to investigate effective manufacturing techniques of CNT integrated multiscale composites. The fabricated composites demonstrated significant improvements in physical properties, such as tensile strength, tensile modulus, inter-laminar shear strength, thermal dimension stability and electrical conductivity. Such multiscale composites were truly multifunctional with the addition of CNTs. Furthermore, a novel hierarchical multiscale modeling method was developed in this research. Molecular dynamic (MD) simulation offered reasonable explanation of CNTs dispersion and their motion in polymer solution. Bi-mode finite-extensible-nonlinear-elastic (FENE) dumbbell simulation was used to analyze the influence of CNT length distribution on the stress tensor and shear-rate-dependent viscosity. Based on the simulated viscosity profile and empirical equations from experiments, a macroscale flow simulation model on the finite element method (FEM) method was developed and validated to predict resin flow behavior in the processing of CNT-enhanced multiscale composites. The proposed multiscale modeling method provided a comprehensive understanding of micro/nano flow in both atomistic details and mesoscale. The simulation model can be used to optimize process design and control of the mold-filling process in multiscale composite manufacturing. This research provided systematic investigations into the CNT-based multiscale composites. The results from this study may be used to leverage the benefits of CNTs and open up new application opportunities for high-performance multifunctional multiscale composites. Keywords. Carbon

  15. A sEMG model with experimentally based simulation parameters.

    Science.gov (United States)

    Wheeler, Katherine A; Shimada, Hiroshima; Kumar, Dinesh K; Arjunan, Sridhar P

    2010-01-01

    A differential, time-invariant, surface electromyogram (sEMG) model has been implemented. While it is based on existing EMG models, the novelty of this implementation is that it assigns more accurate distributions of variables to create realistic motor unit (MU) characteristics. Variables such as muscle fibre conduction velocity, jitter (the change in the interpulse interval between subsequent action potential firings) and motor unit size have been considered to follow normal distributions about an experimentally obtained mean. In addition, motor unit firing frequencies have been considered to have non-linear and type based distributions that are in accordance with experimental results. Motor unit recruitment thresholds have been considered to be related to the MU type. The model has been used to simulate single channel differential sEMG signals from voluntary, isometric contractions of the biceps brachii muscle. The model has been experimentally verified by conducting experiments on three subjects. Comparison between simulated signals and experimental recordings shows that the Root Mean Square (RMS) increases linearly with force in both cases. The simulated signals also show similar values and rates of change of RMS to the experimental signals.

  16. Experimental modeling of injectivity loss; Modelagem experimental da perda de injetividade

    Energy Technology Data Exchange (ETDEWEB)

    Bonato, Adriano Jose do Amaral Mello; Silva, Pedro Glauto de Farias e; Gomes, Vanessa Limeira Azevedo; Santos, Adriano dos [Universidade Federal do Rio Grande do Norte (UFRN), Natal, RN (Brazil)

    2012-07-01

    Produced water reinjection, suspended particles are retained in the porous media causing formation damage and injectivity decline. In general the retention of the particles occurs near the side of injection, this fact occurs in most cases, due to the size exclusion. The modeling of filtration and the consequent formation damage is essential to the project management of water injection in oil reservoirs. Thus, mathematical models are studied to better predict the distribution of particles throughout the porous media and determine the parameters of adjustment to injectivity decline. Among these models, there is the classic model which consists in determining these parameters (coefficient of filtration and formation damage). The methodology used in modeling is given from the equations the mass conservation, kinetic particle retention, the modified Darcy equation and the function formation damage. This study aimed to improve experimental modeling, including development of software for acquisition and processing of experimental data, considering the variable number of pressure measurements along the sample. The software was developed using the Labview 2011 platform and allows the determination of relevant parameters to predict injectivity loss in water injection wells. Furthermore, based on the traditional model of filtration in porous media (including depth filtration and formation of the external plaster), the software was applied to predict injectivity loss in addition to the properties of the grout. Finally, the classical models for transporting suspensions and damage to the formation were observed. (author)

  17. Quality Assurance Program Plan for the Waste Isolation Pilot Plant Experimental-Waste Characterization Program

    International Nuclear Information System (INIS)

    1991-01-01

    This Quality Assurance Program Plan (QAPP) identifies the quality of data necessary to meet the specific objectives associated with the Department of Energy (DOE) Waste Isolation Pilot Plant (WIPP) Experimental-Waste Characterization Program (the Program). This experimental-waste characterization program is only one part of the WIPP Test Phase, both in the short- and long-term, to quantify and evaluate the characteristics and behavior of transuranic (TRU) wastes in the repository environment. Other parts include the bin-scale and alcove tests, drum-scale tests, and laboratory experiments. In simplified terms, the purpose of the Program is to provide chemical, physical, and radiochemical data describing the characteristics of the wastes that will be emplaced in the WIPP, while the remaining WIPP Test Phase is directed at examining the behavior of these wastes in the repository environment. 50 refs., 35 figs., 33 tabs

  18. Investigation of approximate models of experimental temperature characteristics of machines

    Science.gov (United States)

    Parfenov, I. V.; Polyakov, A. N.

    2018-05-01

    This work is devoted to the investigation of various approaches to the approximation of experimental data and the creation of simulation mathematical models of thermal processes in machines with the aim of finding ways to reduce the time of their field tests and reducing the temperature error of the treatments. The main methods of research which the authors used in this work are: the full-scale thermal testing of machines; realization of various approaches at approximation of experimental temperature characteristics of machine tools by polynomial models; analysis and evaluation of modelling results (model quality) of the temperature characteristics of machines and their derivatives up to the third order in time. As a result of the performed researches, rational methods, type, parameters and complexity of simulation mathematical models of thermal processes in machine tools are proposed.

  19. Contact Modelling in Resistance Welding, Part II: Experimental Validation

    DEFF Research Database (Denmark)

    Song, Quanfeng; Zhang, Wenqi; Bay, Niels

    2006-01-01

    Contact algorithms in resistance welding presented in the previous paper are experimentally validated in the present paper. In order to verify the mechanical contact algorithm, two types of experiments, i.e. sandwich upsetting of circular, cylindrical specimens and compression tests of discs...... with a solid ring projection towards a flat ring, are carried out at room temperature. The complete algorithm, involving not only the mechanical model but also the thermal and electrical models, is validated by projection welding experiments. The experimental results are in satisfactory agreement...

  20. Optimality models in the age of experimental evolution and genomics.

    Science.gov (United States)

    Bull, J J; Wang, I-N

    2010-09-01

    Optimality models have been used to predict evolution of many properties of organisms. They typically neglect genetic details, whether by necessity or design. This omission is a common source of criticism, and although this limitation of optimality is widely acknowledged, it has mostly been defended rather than evaluated for its impact. Experimental adaptation of model organisms provides a new arena for testing optimality models and for simultaneously integrating genetics. First, an experimental context with a well-researched organism allows dissection of the evolutionary process to identify causes of model failure--whether the model is wrong about genetics or selection. Second, optimality models provide a meaningful context for the process and mechanics of evolution, and thus may be used to elicit realistic genetic bases of adaptation--an especially useful augmentation to well-researched genetic systems. A few studies of microbes have begun to pioneer this new direction. Incompatibility between the assumed and actual genetics has been demonstrated to be the cause of model failure in some cases. More interestingly, evolution at the phenotypic level has sometimes matched prediction even though the adaptive mutations defy mechanisms established by decades of classic genetic studies. Integration of experimental evolutionary tests with genetics heralds a new wave for optimality models and their extensions that does not merely emphasize the forces driving evolution.

  1. Entanglement of two-mode Gaussian states: characterization and experimental production and manipulation

    Energy Technology Data Exchange (ETDEWEB)

    Laurat, Julien [Laboratoire Kastler Brossel, Case 74, Universite Pierre et Marie curie, 4 Place Jussieu, 75252 Paris cedex 05 (France); Keller, Gaelle [Laboratoire Kastler Brossel, Case 74, Universite Pierre et Marie curie, 4 Place Jussieu, 75252 Paris cedex 05 (France); Oliveira-Huguenin, Jose Augusto [Laboratoire Kastler Brossel, Case 74, Universite Pierre et Marie curie, 4 Place Jussieu, 75252 Paris cedex 05 (France); Fabre, Claude [Laboratoire Kastler Brossel, Case 74, Universite Pierre et Marie curie, 4 Place Jussieu, 75252 Paris cedex 05 (France); Coudreau, Thomas [Laboratoire Kastler Brossel, Case 74, Universite Pierre et Marie curie, 4 Place Jussieu, 75252 Paris cedex 05 (France); Laboratoire Materiaux et Phenomenes Quantiques, Case 7021, Universite Denis Diderot, 2 Place Jussieu, 75251 Paris cedex 05 (France); Serafini, Alessio [Dipartimento di Fisica ' E R Caianiello' , Universita di Salerno (Italy); CNR-Coherentia, Gruppo di Salerno (Italy); and INFN Sezione di Napoli-Gruppo Collegato di Salerno, Via S Allende, 84081 Baronissi (Saudi Arabia) (Italy); Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT (United Kingdom); Adesso, Gerardo [Dipartimento di Fisica ' E R Caianiello' , Universita di Salerno (Italy); CNR-Coherentia, Gruppo di Salerno (Italy); and INFN Sezione di Napoli-Gruppo Collegato di Salerno, Via S Allende, 84081 Baronissi (Saudi Arabia) (Italy); Illuminati, Fabrizio [Dipartimento di Fisica ' E R Caianiello' , Universita di Salerno (Italy) and CNR-Coherentia, Gruppo di Salerno (Italy) and INFN Sezione di Napoli-Gruppo Collegato di Salerno, Via S Allende, 84081 Baronissi (SA) (Italy)

    2005-12-01

    A powerful theoretical structure has emerged in recent years on the characterization and quantification of entanglement in continuous-variable systems. After reviewing this framework, we will illustrate it with an original set-up based on a type-II OPO (optical parametric oscillator) with adjustable mode coupling. Experimental results allow a direct verification of many theoretical predictions and provide a sharp insight into the general properties of two-mode Gaussian states and entanglement resource manipulation.

  2. Entanglement of two-mode Gaussian states: characterization and experimental production and manipulation

    International Nuclear Information System (INIS)

    Laurat, Julien; Keller, Gaelle; Oliveira-Huguenin, Jose Augusto; Fabre, Claude; Coudreau, Thomas; Serafini, Alessio; Adesso, Gerardo; Illuminati, Fabrizio

    2005-01-01

    A powerful theoretical structure has emerged in recent years on the characterization and quantification of entanglement in continuous-variable systems. After reviewing this framework, we will illustrate it with an original set-up based on a type-II OPO (optical parametric oscillator) with adjustable mode coupling. Experimental results allow a direct verification of many theoretical predictions and provide a sharp insight into the general properties of two-mode Gaussian states and entanglement resource manipulation

  3. Highlighting the Need for Systems-level Experimental Characterization of Plant Metabolic Enzymes

    Directory of Open Access Journals (Sweden)

    Martin Karl Magnus Engqvist

    2016-07-01

    Full Text Available The biology of living organisms is determined by the action and interaction of a large number of individual gene products, each with specific functions. Discovering and annotating the function of gene products is key to our understanding of these organisms. Controlled experiments and bioinformatic predictions both contribute to functional gene annotation. For most species it is difficult to gain an overview of what portion of gene annotations are based on experiments and what portion represent predictions. Here, I survey the current state of experimental knowledge of enzymes and metabolism in Arabidopsis thaliana as well as eleven economically important crops and forestry trees – with a particular focus on reactions involving organic acids in central metabolism. I illustrate the limited availability of experimental data for functional annotation of enzymes in most of these species. Many enzymes involved in metabolism of citrate, malate, fumarate, lactate, and glycolate in crops and forestry trees have not been characterized. Furthermore, enzymes involved in key biosynthetic pathways which shape important traits in crops and forestry trees have not been characterized. I argue for the development of novel high-throughput platforms with which limited functional characterization of gene products can be performed quickly and relatively cheaply. I refer to this approach as systems-level experimental characterization. The data collected from such platforms would form a layer intermediate between bioinformatic gene function predictions and in-depth experimental studies of these functions. Such a data layer would greatly aid in the pursuit of understanding a multiplicity of biological processes in living organisms.

  4. Team Modelling: Review of Experimental Scenarios and Computational Models

    Science.gov (United States)

    2006-09-01

    les auteurs ont réuni et examiné des scénarios ayant servi dans le cadre d’études antérieures sur les équipes, ils ont développé d’importants...cognition, perception, sensation, motor action and knowledge, that embody a principled underlying theory or framework for human information...Processing) integrates Qinetiq’s (POP) model with DRDC’s IP/PCT (Perceptual Control Theory ) models. In particular, the POP/IP model includes the

  5. Instrumental and ethical aspects of experimental research with animal models

    Directory of Open Access Journals (Sweden)

    Mirian Watanabe

    2014-02-01

    Full Text Available Experimental animal models offer possibilities of physiology knowledge, pathogenesis of disease and action of drugs that are directly related to quality nursing care. This integrative review describes the current state of the instrumental and ethical aspects of experimental research with animal models, including the main recommendations of ethics committees that focus on animal welfare and raises questions about the impact of their findings in nursing care. Data show that, in Brazil, the progress in ethics for the use of animals for scientific purposes was consolidated with Law No. 11.794/2008 establishing ethical procedures, attending health, genetic and experimental parameters. The application of ethics in handling of animals for scientific and educational purposes and obtaining consistent and quality data brings unquestionable contributions to the nurse, as they offer subsidies to relate pathophysiological mechanisms and the clinical aspect on the patient.

  6. Moisture damage susceptibility of asphalt mixtures : Experimental characterization and modelling

    NARCIS (Netherlands)

    Varveri, A.

    2017-01-01

    A well-functioning, long-lasting and safe highway infrastructure network ensures the mobility of people and facilitates the transport of goods, promoting thus environmental, economic, and social sustainability. The development of sustainable highway infrastructure requires, among other activities,

  7. Moisture damage susceptibility of asphalt mixtures: Experimental characterization and modelling

    OpenAIRE

    Varveri, A.

    2017-01-01

    A well-functioning, long-lasting and safe highway infrastructure network ensures the mobility of people and facilitates the transport of goods, promoting thus environmental, economic, and social sustainability. The development of sustainable highway infrastructure requires, among other activities, the construction of pavement systems with enhanced durability. Moisture damage in asphalt pavements is associated with inferior performance, unexpected failures and reduced service life. All of thes...

  8. Experimental Characterization and Modeling of Advanced Polymer Composite Window Frames

    DEFF Research Database (Denmark)

    Zajas, Jan Jakub

    Even though the window frames cover a relatively small fraction of the entire building envelope, they are responsible for a major amount of heat loss, due to their poor insulation properties compared to the other envelope elements. With the current trends to reduce energy use in buildings....... Heat transfer through a frame is a combination of conduction, convection and radiation and each of these mechanisms of heat transfer can be diminished in certain ways. An example could be subdividing the cavities to reduce convective heat flow or using low emissivity materials to limit the thermal......, it is obvious that the thermal performance of contemporary frames needs to be improved, so that buildings can fulfill the new, more rigorous demands. This study will focus on improving the thermal performance of window frames made of fiberglass reinforced plastic (FRP). This material has been recently...

  9. Constitutive Model Calibration via Autonomous Multiaxial Experimentation (Postprint)

    Science.gov (United States)

    2016-09-17

    ABSTRACT (Maximum 200 words) Modern plasticity models contain numerous parameters that can be difficult and time consuming to fit using current...Abstract Modern plasticity models contain numerous parameters that can be difficult and time consuming to fit using current methods. Additional...complexity, is a difficult and time consuming process that has historically be a separate process from the experimental testing. As such, additional

  10. Experimental Analysis and Model Validation of an Opaque Ventilated Facade

    DEFF Research Database (Denmark)

    López, F. Peci; Jensen, Rasmus Lund; Heiselberg, Per

    2012-01-01

    Natural ventilation is a convenient way of reducing energy consumption in buildings. In this study an experimental module of an opaque ventilated façade (OVF) was built and tested for assessing its potential of supplying free ventilation and air preheating for the building. A numerical model was ...

  11. Capillary microreactors for lactic acid extraction: experimental and modelling study

    NARCIS (Netherlands)

    Susanti, Susanti; Winkelman, Jozef; Schuur, Boelo; Heeres, Hero; Yue, Jun

    2015-01-01

    Lactic acid is an important biobased chemical and, among others, is used for the production of poly-lactic acid. Down-stream processing using state of the art technology is energy intensive and leads to the formation of large amounts of salts. In this presentation, experimental and modeling studies

  12. Experimental data available for radiation damage modelling in reactor materials

    International Nuclear Information System (INIS)

    Wollenberger, H.

    Radiation damage modelling requires rate constants for production, annihilation and trapping of defects. The literature is reviewed with respect to experimental determination of such constants. Useful quantitative information exists only for Cu and Al. Special emphasis is given to the temperature dependence of the rate constants

  13. Low dose CT simulation using experimental noise model

    Energy Technology Data Exchange (ETDEWEB)

    Nakanishi, Satori; Zamyatin, Alexander A. [Toshiba Medical Systems Corporation, Tochigi, Otawarashi (Japan); Silver, Michael D. [Toshiba Medical Research Institute, Vernon Hills, IL (United States)

    2011-07-01

    We suggest a method to obtain system noise model experimentally without relying on assumptions on statistical distribution of the noise; also, knowledge of DAS gain and electronic noise level are not required. Evaluation with ultra-low dose CT data (5 mAs) shows good match between simulated and real data noise. (orig.)

  14. Characterization and optimization of the RA-3 experimental dosimetry for normal sheep lung radio-tolerance study

    International Nuclear Information System (INIS)

    Soto, M.S.; Gonzalez, S.J.; Thorp, Silvia I.; Pozzi, Emiliano; Gadan, M.; Miller, Marcelo; Farias, R.

    2009-01-01

    In the spirit of the novel technique proposed by the University of Pavia group (Italy) to irradiate an isolated organ using BNCT, the Comision Nacional de Energia Atomica (CNEA) in collaboration with the Fundacion Favaloro has initiated a project that aims to investigate the feasibility of BNCT for ex-situ treatment of diffuse metastatic disease in the lungs. The present work was carried out in the framework of the undergoing experimental study of the radio tolerance of normal sheep lung. With the purpose of characterizing and optimizing the resulting experimental dosimetry in normal lung subjected to neutron irradiation in the BNCT facility of the RA-3 reactor (CNEA), we have performed a series of experiments to find the optimum configuration of the container-lung system deriving a dose distribution preferentially uniform throughout the organ. Once the optimal set-up was established, we measured the total gamma dose rate and estimated the irradiation time compatible with the maximum tolerable dose of normal lung resulting from previous studies in rats. This estimation was performed using RBE, CBE and tolerance dose values derived from radiobiological studies with BNCT. In parallel with the experimental characterization, we built two different computational models of the container-lung system to perform Monte Carlo simulation with MCNP and Treatment Planning System NCTPlan. (author)

  15. Synthesis, characterization and antistructure modeling of Ni nano ferrite

    Science.gov (United States)

    Kane, S. N.; Raghuvanshi, S.; Satalkar, M.; Reddy, V. R.; Deshpande, U. P.; Tatarchuk, T. R.; Mazaleyrat, F.

    2018-05-01

    We report the role played by cation distribution in determining magnetic properties by comparing dry gel, thermally annealed Ni ferrite prepared by sol-gel auto-combustion technique. X-ray diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM) and Mössbauer spectroscopy were used to characterize the samples. Both XRD and Mössbauer measurements validate the formation of spinel phase with grain diameter 39.13-45.53 nm. First time antistructural modeling for Ni ferrite is reported to get information on active surface centers. Decrease of Debye temperature θD in annealed sample shows enhancement of lattice vibrations. With thermal annealing experimental and Néel magnetic moment (nBe, nBN) increases, suggesting migration of Ni2+ from B to A site with concurrent migration of Fe3+ from A to B site (non-equilibrium cationic distribution), affecting magnetic properties.

  16. Streamlined Modeling for Characterizing Spacecraft Anomalous Behavior

    Science.gov (United States)

    Klem, B.; Swann, D.

    2011-09-01

    Anomalous behavior of on-orbit spacecraft can often be detected using passive, remote sensors which measure electro-optical signatures that vary in time and spectral content. Analysts responsible for assessing spacecraft operational status and detecting detrimental anomalies using non-resolved imaging sensors are often presented with various sensing and identification issues. Modeling and measuring spacecraft self emission and reflected radiant intensity when the radiation patterns exhibit a time varying reflective glint superimposed on an underlying diffuse signal contribute to assessment of spacecraft behavior in two ways: (1) providing information on body component orientation and attitude; and, (2) detecting changes in surface material properties due to the space environment. Simple convex and cube-shaped spacecraft, designed to operate without protruding solar panel appendages, may require an enhanced level of preflight characterization to support interpretation of the various physical effects observed during on-orbit monitoring. This paper describes selected portions of the signature database generated using streamlined signature modeling and simulations of basic geometry shapes apparent to non-imaging sensors. With this database, summarization of key observable features for such shapes as spheres, cylinders, flat plates, cones, and cubes in specific spectral bands that include the visible, mid wave, and long wave infrared provide the analyst with input to the decision process algorithms contained in the overall sensing and identification architectures. The models typically utilize baseline materials such as Kapton, paints, aluminum surface end plates, and radiators, along with solar cell representations covering the cylindrical and side portions of the spacecraft. Multiple space and ground-based sensors are assumed to be located at key locations to describe the comprehensive multi-viewing aspect scenarios that can result in significant specular reflection

  17. A physically-based constitutive model for SA508-III steel: Modeling and experimental verification

    Energy Technology Data Exchange (ETDEWEB)

    Dong, Dingqian [National Die & Mold CAD Engineering Research Center, Shanghai Jiao Tong University, 1954 Huashan Rd., Shanghai 200030 (China); Chen, Fei, E-mail: feechn@gmail.com [National Die & Mold CAD Engineering Research Center, Shanghai Jiao Tong University, 1954 Huashan Rd., Shanghai 200030 (China); Department of Mechanical, Materials and Manufacturing Engineering, University of Nottingham, Nottingham NG7 2RD (United Kingdom); Cui, Zhenshan, E-mail: cuizs@sjtu.edu.cn [National Die & Mold CAD Engineering Research Center, Shanghai Jiao Tong University, 1954 Huashan Rd., Shanghai 200030 (China)

    2015-05-14

    Due to its good toughness and high weldability, SA508-III steel has been widely used in the components manufacturing of reactor pressure vessels (RPV) and steam generators (SG). In this study, the hot deformation behaviors of SA508-III steel are investigated by isothermal hot compression tests with forming temperature of (950–1250)°C and strain rate of (0.001–0.1)s{sup −1}, and the corresponding flow stress curves are obtained. According to the experimental results, quantitative analysis of work hardening and dynamic softening behaviors is presented. The critical stress and critical strain for initiation of dynamic recrystallization are calculated by setting the second derivative of the third order polynomial. Based on the classical stress–dislocation relation and the kinetics of dynamic recrystallization, a two-stage constitutive model is developed to predict the flow stress of SA508-III steel. Comparisons between the predicted and measured flow stress indicate that the established physically-based constitutive model can accurately characterize the hot deformations for the steel. Furthermore, a successful numerical simulation of the industrial upsetting process is carried out by implementing the developed constitutive model into a commercial software, which evidences that the physically-based constitutive model is practical and promising to promote industrial forging process for nuclear components.

  18. A physically-based constitutive model for SA508-III steel: Modeling and experimental verification

    International Nuclear Information System (INIS)

    Dong, Dingqian; Chen, Fei; Cui, Zhenshan

    2015-01-01

    Due to its good toughness and high weldability, SA508-III steel has been widely used in the components manufacturing of reactor pressure vessels (RPV) and steam generators (SG). In this study, the hot deformation behaviors of SA508-III steel are investigated by isothermal hot compression tests with forming temperature of (950–1250)°C and strain rate of (0.001–0.1)s −1 , and the corresponding flow stress curves are obtained. According to the experimental results, quantitative analysis of work hardening and dynamic softening behaviors is presented. The critical stress and critical strain for initiation of dynamic recrystallization are calculated by setting the second derivative of the third order polynomial. Based on the classical stress–dislocation relation and the kinetics of dynamic recrystallization, a two-stage constitutive model is developed to predict the flow stress of SA508-III steel. Comparisons between the predicted and measured flow stress indicate that the established physically-based constitutive model can accurately characterize the hot deformations for the steel. Furthermore, a successful numerical simulation of the industrial upsetting process is carried out by implementing the developed constitutive model into a commercial software, which evidences that the physically-based constitutive model is practical and promising to promote industrial forging process for nuclear components

  19. Robust Bayesian Experimental Design for Conceptual Model Discrimination

    Science.gov (United States)

    Pham, H. V.; Tsai, F. T. C.

    2015-12-01

    A robust Bayesian optimal experimental design under uncertainty is presented to provide firm information for model discrimination, given the least number of pumping wells and observation wells. Firm information is the maximum information of a system can be guaranteed from an experimental design. The design is based on the Box-Hill expected entropy decrease (EED) before and after the experiment design and the Bayesian model averaging (BMA) framework. A max-min programming is introduced to choose the robust design that maximizes the minimal Box-Hill EED subject to that the highest expected posterior model probability satisfies a desired probability threshold. The EED is calculated by the Gauss-Hermite quadrature. The BMA method is used to predict future observations and to quantify future observation uncertainty arising from conceptual and parametric uncertainties in calculating EED. Monte Carlo approach is adopted to quantify the uncertainty in the posterior model probabilities. The optimal experimental design is tested by a synthetic 5-layer anisotropic confined aquifer. Nine conceptual groundwater models are constructed due to uncertain geological architecture and boundary condition. High-performance computing is used to enumerate all possible design solutions in order to identify the most plausible groundwater model. Results highlight the impacts of scedasticity in future observation data as well as uncertainty sources on potential pumping and observation locations.

  20. Systematic integration of experimental data and models in systems biology.

    Science.gov (United States)

    Li, Peter; Dada, Joseph O; Jameson, Daniel; Spasic, Irena; Swainston, Neil; Carroll, Kathleen; Dunn, Warwick; Khan, Farid; Malys, Naglis; Messiha, Hanan L; Simeonidis, Evangelos; Weichart, Dieter; Winder, Catherine; Wishart, Jill; Broomhead, David S; Goble, Carole A; Gaskell, Simon J; Kell, Douglas B; Westerhoff, Hans V; Mendes, Pedro; Paton, Norman W

    2010-11-29

    The behaviour of biological systems can be deduced from their mathematical models. However, multiple sources of data in diverse forms are required in the construction of a model in order to define its components and their biochemical reactions, and corresponding parameters. Automating the assembly and use of systems biology models is dependent upon data integration processes involving the interoperation of data and analytical resources. Taverna workflows have been developed for the automated assembly of quantitative parameterised metabolic networks in the Systems Biology Markup Language (SBML). A SBML model is built in a systematic fashion by the workflows which starts with the construction of a qualitative network using data from a MIRIAM-compliant genome-scale model of yeast metabolism. This is followed by parameterisation of the SBML model with experimental data from two repositories, the SABIO-RK enzyme kinetics database and a database of quantitative experimental results. The models are then calibrated and simulated in workflows that call out to COPASIWS, the web service interface to the COPASI software application for analysing biochemical networks. These systems biology workflows were evaluated for their ability to construct a parameterised model of yeast glycolysis. Distributed information about metabolic reactions that have been described to MIRIAM standards enables the automated assembly of quantitative systems biology models of metabolic networks based on user-defined criteria. Such data integration processes can be implemented as Taverna workflows to provide a rapid overview of the components and their relationships within a biochemical system.

  1. Waste glass corrosion modeling: Comparison with experimental results

    International Nuclear Information System (INIS)

    Bourcier, W.L.

    1994-01-01

    Models for borosilicate glass dissolution must account for the processes of (1) kinetically-controlled network dissolution, (2) precipitation of secondary phases, (3) ion exchange, (4) rate-limiting diffusive transport of silica through a hydrous surface reaction layer, and (5) specific glass surface interactions with dissolved cations and anions. Current long-term corrosion models for borosilicate glass employ a rate equation consistent with transition state theory embodied in a geochemical reaction-path modeling program that calculates aqueous phase speciation and mineral precipitation/dissolution. These models are currently under development. Future experimental and modeling work to better quantify the rate-controlling processes and validate these models are necessary before the models can be used in repository performance assessment calculations

  2. Microstructure evolution during homogenization of Al–Mn–Fe–Si alloys: Modeling and experimental results

    International Nuclear Information System (INIS)

    Du, Q.; Poole, W.J.; Wells, M.A.; Parson, N.C.

    2013-01-01

    Microstructure evolution during the homogenization heat treatment of Al–Mn–Fe–Si, or AA3xxx, alloys has been investigated using a combination of modeling and experimental studies. The model is fully coupled to CALculation PHAse Diagram (CALPHAD) software and has explicitly taken into account the two different length scales for diffusion encountered in modeling the homogenization process. The model is able to predict the evolution of all the important microstructural features during homogenization, including the inhomogeneous spatial distribution of dispersoids and alloying elements in solution, the dispersoid number density and the size distribution, and the type and fraction of intergranular constituent particles. Experiments were conducted using four direct chill (DC) cast AA3xxx alloys subjected to various homogenization treatments. The resulting microstructures were then characterized using a range of characterization techniques, including optical and electron microscopy, electron micro probe analysis, field emission gun scanning electron microscopy, and electrical resistivity measurements. The model predictions have been compared with the experimental measurements to validate the model. Further, it has been demonstrated that the validated model is able to predict the effects of alloying elements (e.g. Si and Mn) on microstructure evolution. It is concluded that the model provides a time and cost effective tool in optimizing and designing industrial AA3xxx alloy chemistries and homogenization heat treatments

  3. Modeling RERTR experimental fuel plates using the PLATE code

    International Nuclear Information System (INIS)

    Hayes, S.L.; Meyer, M.K.; Hofman, G.L.; Snelgrove, J.L.; Brazener, R.A.

    2003-01-01

    Modeling results using the PLATE dispersion fuel performance code are presented for the U-Mo/Al experimental fuel plates from the RERTR-1, -2, -3 and -5 irradiation tests. Agreement of the calculations with experimental data obtained in post-irradiation examinations of these fuels, where available, is shown to be good. Use of the code to perform a series of parametric evaluations highlights the sensitivity of U-Mo dispersion fuel performance to fabrication variables, especially fuel particle shape and size distributions. (author)

  4. Physics of human cooperation: experimental evidence and theoretical models

    Science.gov (United States)

    Sánchez, Angel

    2018-02-01

    In recent years, many physicists have used evolutionary game theory combined with a complex systems perspective in an attempt to understand social phenomena and challenges. Prominent among such phenomena is the issue of the emergence and sustainability of cooperation in a networked world of selfish or self-focused individuals. The vast majority of research done by physicists on these questions is theoretical, and is almost always posed in terms of agent-based models. Unfortunately, more often than not such models ignore a number of facts that are well established experimentally, and are thus rendered irrelevant to actual social applications. I here summarize some of the facts that any realistic model should incorporate and take into account, discuss important aspects underlying the relation between theory and experiments, and discuss future directions for research based on the available experimental knowledge.

  5. Experimental, statistical, and biological models of radon carcinogenesis

    International Nuclear Information System (INIS)

    Cross, F.T.

    1991-09-01

    Risk models developed for underground miners have not been consistently validated in studies of populations exposed to indoor radon. Imprecision in risk estimates results principally from differences between exposures in mines as compared to domestic environments and from uncertainties about the interaction between cigarette-smoking and exposure to radon decay products. Uncertainties in extrapolating miner data to domestic exposures can be reduced by means of a broad-based health effects research program that addresses the interrelated issues of exposure, respiratory tract dose, carcinogenesis (molecular/cellular and animal studies, plus developing biological and statistical models), and the relationship of radon to smoking and other copollutant exposures. This article reviews experimental animal data on radon carcinogenesis observed primarily in rats at Pacific Northwest Laboratory. Recent experimental and mechanistic carcinogenesis models of exposures to radon, uranium ore dust, and cigarette smoke are presented with statistical analyses of animal data. 20 refs., 1 fig

  6. Experimental studying the effects of horizontal experimental channels on the neutron field in the model of the TVR-M research reactor core

    International Nuclear Information System (INIS)

    Shvedov, O.V.; Aitov, G.M.; Balyuk, S.A.

    1989-01-01

    The effect of horizontal channels on the neutron field in the core of the TVR-M heavy-water cooled high-flux research reactor is experimentally studied. The experiments are carried out in a critical assembly using full-scale core model. The data are obtained characterizing soft and rigid effects of horizontal experimental channels on neutron field. The soft effect is connected with the total mass of experimental channels. It is practically uniform by the core azimuth and reveals itself in the decrease of neutron burst in the reflector, and, consequently in the decrease of neutron field distorsion in the external and middle fuel assembly rows. The rigid effect is conditioned by separate experimental channels located close to the core. It brings about local disturbance in the closest fuel assemblies. The data obtained are a part of experimental program on studying basis power distributions in the TVR-M reactor lattices. 2 refs.; 18 figs

  7. Development of experimental alloxan model of diabetes mellitus

    Directory of Open Access Journals (Sweden)

    V.V. Semenko

    2017-05-01

    Full Text Available Background. One of the main causes that lead to the disability of diabetic patients is diabetic retinopathy (DR. The relevance of the problem of DR necessitates the development of optimal experimental models on experimental animals to find effective ways of correcting this pathology. The purpose of our work was to develop an experimental alloxan model of type 1 diabetes mellitus (DM for the study of DR, which would not result in the lethal outcome of experimental animals under the action of alloxan; histological examination of changes in the tissues of the eyeball in the reproduction of the DM model for the selection of new effective methods for the metabolic treatment of DR in the early stages. Materials and methods. The experiment was carried out on white outbred Wistar rats weighing 180–200 g. The first group consisted of 20 animals that were not subjected to any influence, served as a control; second group — 30 animals, in which DM was modeled by administration of alloxan and fructose. Results. When modeling DR, vessel changes in the form of wall fibrosis, edema of the endothelium and vasospasm were found. There was also a decrease in the amount of pigment granules, dystrophic changes in the cells of the ganglionic layer and a layer of retinal rods and cones, which coincides with the descriptions of damage to the coats of the eyeball in patients with DM. Conclusions. In our studies, we have calculated the optimal dose of alloxan administration, which does not lead to the death of rats (the lethality of rats was absent and is an effective model not only of DM in general, but also of DR.

  8. Experimental Evaluation of Equivalent-Fluid Models for Melamine Foam

    Science.gov (United States)

    Allen, Albert R.; Schiller, Noah H.

    2016-01-01

    Melamine foam is a soft porous material commonly used in noise control applications. Many models exist to represent porous materials at various levels of fidelity. This work focuses on rigid frame equivalent fluid models, which represent the foam as a fluid with a complex speed of sound and density. There are several empirical models available to determine these frequency dependent parameters based on an estimate of the material flow resistivity. Alternatively, these properties can be experimentally educed using an impedance tube setup. Since vibroacoustic models are generally sensitive to these properties, this paper assesses the accuracy of several empirical models relative to impedance tube measurements collected with melamine foam samples. Diffuse field sound absorption measurements collected using large test articles in a laboratory are also compared with absorption predictions determined using model-based and measured foam properties. Melamine foam slabs of various thicknesses are considered.

  9. Experimental validation of a Bayesian model of visual acuity.

    LENUS (Irish Health Repository)

    Dalimier, Eugénie

    2009-01-01

    Based on standard procedures used in optometry clinics, we compare measurements of visual acuity for 10 subjects (11 eyes tested) in the presence of natural ocular aberrations and different degrees of induced defocus, with the predictions given by a Bayesian model customized with aberrometric data of the eye. The absolute predictions of the model, without any adjustment, show good agreement with the experimental data, in terms of correlation and absolute error. The efficiency of the model is discussed in comparison with image quality metrics and other customized visual process models. An analysis of the importance and customization of each stage of the model is also given; it stresses the potential high predictive power from precise modeling of ocular and neural transfer functions.

  10. Durability of concrete: characterization and modeling of physical and chemical degradation of cement

    International Nuclear Information System (INIS)

    Adenot, Frederic

    1992-01-01

    Within the frame of nuclear waste management, and more particularly waste storage by confinement in parcels, concrete and geological environment, this research aims at predicting the durability of a concrete paste and of all concrete works. This prediction is based on a material characterization (determination of the thickness and composition of the attacked area) whatever the degradation duration is. The adopted approach is to model concrete lixiviation and to compare model results with experimental results. The model is also used to assess the influence of a great number of parameters, and to simulate non experimented cases. Thus, the author reports a bibliographical study on cement, and presents the equations of a lixiviation model. He reports experiments aimed at verifying modelling hypotheses and at acquiring necessary data. The model is then numerically solved, and applied to an experimental case. Experimental results are compared with modelling results, and a prediction is performed for a 300 year-duration [fr

  11. Uterus transplantation: Experimental animal models and recent experience in humans

    Directory of Open Access Journals (Sweden)

    Sadık Şahin

    2015-03-01

    Full Text Available Uterus transplantation has been considered as an alternative management modality in the last few years for adoption or gestational surrogacy for women with absence of uterus due to congenital or acquired reasons. Surrogacy is legal in only a few countries because of ethical, social and legal issues. Up to date, a total of 11 uterus transplantation cases have been reported in which uteri were harvested from ten live donors and one donor with brain death. After unsuccessful attempt of first uterus transplantation, many studies have been conducted in animals and these experimental models enabled our knowledge to increase on this topic. First experimental studies were performed in rodents; later uterus transplantation was accomplished in sheep, pigs and rabbits. Recently, researches in non-human primates have led the experience regarding transplantation technique and success to improve. In this review, we reviewed the experimental animal researches in the area of uterus transplantation and recent experience in humans.

  12. The rabbit as an experimental model in laryngology

    Directory of Open Access Journals (Sweden)

    Carneiro, Christiano de Giacomo

    2009-06-01

    Full Text Available Introduction: In the research in laryngology we normally use animal models. The animal experimentation may also contribute largely for this evolution, mainly for the easy access compared to human larynxes and for they are more easily controlled. Objective: The objective of this work is to analyze the laryngofissure with vocal cords graft as an experimental surgical technique in male adult rabbits. Method: We studied 46 New Zealand albino rabbits submitted to microsurgery in both vocal cords with autologous unilateral or bilateral graft of fat or fascia. Results: There were 4 losses of 3 animals until the first week of the postoperative period and another after 19 days after surgery. In the subsequent animals there were no infection, hematoma or sutures dehiscence. Conclusion: The study enables the conclusion that the experimental laryngofissure in rabbits is a safe method that may be used for laryngological studies.

  13. Genetic algorithms and experimental discrimination of SUSY models

    International Nuclear Information System (INIS)

    Allanach, B.C.; Quevedo, F.; Grellscheid, D.

    2004-01-01

    We introduce genetic algorithms as a means to estimate the accuracy required to discriminate among different models using experimental observables. We exemplify the technique in the context of the minimal supersymmetric standard model. If supersymmetric particles are discovered, models of supersymmetry breaking will be fit to the observed spectrum and it is beneficial to ask beforehand: what accuracy is required to always allow the discrimination of two particular models and which are the most important masses to observe? Each model predicts a bounded patch in the space of observables once unknown parameters are scanned over. The questions can be answered by minimising a 'distance' measure between the two hypersurfaces. We construct a distance measure that scales like a constant fraction of an observable, since that is how the experimental errors are expected to scale. Genetic algorithms, including concepts such as natural selection, fitness and mutations, provide a solution to the minimisation problem. We illustrate the efficiency of the method by comparing three different classes of string models for which the above questions could not be answered with previous techniques. The required accuracy is in the range accessible to the Large Hadron Collider (LHC) when combined with a future linear collider (LC) facility. The technique presented here can be applied to more general classes of models or observables. (author)

  14. Transvaginal ultrasound ovarian diathermy: sheep as an experimental model

    Directory of Open Access Journals (Sweden)

    Pimentel Anita M

    2012-01-01

    Full Text Available Abstract Background Some techniques of transvaginal ovarian drilling have been previously described. Nevertheless a monopolar transvaginal ovarian cauterization, that use the expertise and safety of transvaginal puncture for oocyte captation seems to be an easier and feasible approach. The aim of this study was to develop a minimally invasive ovarian cauterization technique under transvaginal ultrasound control, and to evaluate the safety of the transvaginal ovarian monopolar cauterization, female sheep at reproductive age were used as an experimental model. Findings An experimental study was performed in a university research center. Seventeen female sheep (15 Corriedale e 2 Suffolk in reproductive age were submitted to transvaginal ovarian cauterization with a monopolar Valleylab Force 2 electrocautery. Macroscopic and microscopic lesions were assessed. Ovarian size were 1.31 cm2 ± 0,43 (Corriedale and 3.41 cm2 ± 0,64 (Suffolk. From 30 ovaries from Corriedale sheep punctured, only 3 were cauterized, presenting macroscopic and typical microscopic lesion. In the Suffolk sheep group, only one ovary was cauterized. No lesion could be found in the needle path. Conclusions This is the first experimental animal model described for ovarian cauterization needle guided by transvaginal ultrasound. The sheep does not seem to be the ideal animal model to study this technique. Another animal model, whose ovaries are better identified by transvaginal ultrasound should be sought for this technique, theoretically less invasive, before it could be offered safely to women with polycystic ovary syndrome.

  15. Experimental designs for autoregressive models applied to industrial maintenance

    International Nuclear Information System (INIS)

    Amo-Salas, M.; López-Fidalgo, J.; Pedregal, D.J.

    2015-01-01

    Some time series applications require data which are either expensive or technically difficult to obtain. In such cases scheduling the points in time at which the information should be collected is of paramount importance in order to optimize the resources available. In this paper time series models are studied from a new perspective, consisting in the use of Optimal Experimental Design setup to obtain the best times to take measurements, with the principal aim of saving costs or discarding useless information. The model and the covariance function are expressed in an explicit form to apply the usual techniques of Optimal Experimental Design. Optimal designs for various approaches are computed and their efficiencies are compared. The methods working in an application of industrial maintenance of a critical piece of equipment at a petrochemical plant are shown. This simple model allows explicit calculations in order to show openly the procedure to find the correlation structure, needed for computing the optimal experimental design. In this sense the techniques used in this paper to compute optimal designs may be transferred to other situations following the ideas of the paper, but taking into account the increasing difficulty of the procedure for more complex models. - Highlights: • Optimal experimental design theory is applied to AR models to reduce costs. • The first observation has an important impact on any optimal design. • Either the lack of precision or small starting observations claim for large times. • Reasonable optimal times were obtained relaxing slightly the efficiency. • Optimal designs were computed in a predictive maintenance context

  16. Prediction and experimental characterization of the molecular architecture of FRP and ATRP synthesized polyacrylate networks

    OpenAIRE

    Gonçalves, Miguel; Dias, Rolando; Costa, Mário Rui

    2009-01-01

    This work reports experimental and modeling studies concerning the conventional (FRP) and atom transfer radical polymerization (ATRP) of acrylate/diacrylate monomers. In the framework of a recently developed general approach, kinetic models including crosslinking reactions and branching by chain transfer to polymer are discussed for FRP and ATRP polymerization systems. Besides molecular weight distribution (MWD), fairly good predictions of the z-average radius of gyration could be obtained fo...

  17. Effects of Erdosteine on Experimental Acute Pancreatitis Model.

    Science.gov (United States)

    Karapolat, Banu; Karapolat, Sami; Gurleyik, Emin; Yasar, Mehmet

    2017-10-01

    To create acute pancreatitis condition experimentally in rats using cerulein, and to reveal histopathological effects in pancreatic tissue with erdosteine. An experimental study. Department of General Surgery, Duzce University, Turkey, from June to October 2014. Thirty male Wistar albino rats were divided into three groups. No procedures were applied to Group 1. The rats in Group 2 and Group 3 were injected cerulein, to establish an experimental pancreatitis model and the blood amylase and lipase values were examined. The rats in Group 3 were given 10 mg/kg erdosteine. This treatment was continued for another 2 days and the rats were sacrificed. The pancreatic tissues were examined histopathologically for edema, inflammation, acinar necrosis, fat necrosis, and vacuolization. The lipase and amylase values and the histopathological examination of pancreatic tissues evidenced that the experimental acute pancreatitis model was established and edema, inflammation, acinar necrosis, fat necrosis, and vacuolization were observed in the pancreatic tissues. The statistical results suggest that erdosteine can decrease the edema, inflammation, acinar necrosis, fat necrosis and vacuolization scores in the tissues. The severity of acute pancreatitis, induced by cerulein in rats, is reduced with the use of erdosteine.

  18. Experimental animal data and modeling of late somatic effects

    International Nuclear Information System (INIS)

    Fry, R.J.M.

    1988-01-01

    This section is restricted to radiation-induced life shortening and cancer and mainly to studies with external radiation. The emphasis will be on the experimental data that are available and the experimental systems that could provide the type of data with which to either formulate or test models. Genetic effects which are of concern are not discussed in this section. Experimental animal radiation studies fall into those that establish general principles and those that demonstrate mechanisms. General principles include the influence of dose, radiation quality, dose rate, fractionation, protraction and such biological factors as age and gender. The influence of these factors are considered as general principles because they are independent, at least qualitatively, of the species studied. For example, if an increase in the LET of the radiation causes an increased effectiveness in cancer induction in a mouse a comparable increase in effectiveness can be expected in humans. Thus, models, whether empirical or mechanistic, formulated from experimental animal data should be generally applicable

  19. Performance Demonstration Program Plan for the WIPP Experimental-Waste Characterization Program

    International Nuclear Information System (INIS)

    1991-02-01

    The Performance Demonstration Program is designed to ensure that compliance with the Quality Assurance Objective, identified in the Quality Assurance Program Plan for the WIPP Experimental-Waste Characterization Program (QAPP), is achieved. This Program Plan is intended for use by the WPO to assess the laboratory support provided for the characterization of WIPP TRU waste by the storage/generator sites. Phase 0 of the Performance Demonstration Program encompasses the analysis of headspace gas samples for inorganic and organic components. The WPO will ensure the implementation of this plan by designating an independent organization to coordinate and provide technical oversight for the program (Program Coordinator). Initial program support, regarding the technical oversight and coordination functions, shall be provided by the USEPA-ORP. This plan identifies the criteria that will be used for the evaluation of laboratory performance, the responsibilities of the Program Coordinator, and the responsibilities of the participating laboratories. 5 tabs

  20. Validation of the newborn larynx modeling with aerodynamical experimental data.

    Science.gov (United States)

    Nicollas, R; Giordano, J; Garrel, R; Medale, M; Caminat, P; Giovanni, A; Ouaknine, M; Triglia, J M

    2009-06-01

    Many authors have studied adult's larynx modelization, but the mechanisms of newborn's voice production have very rarely been investigated. After validating a numerical model with acoustic data, studies were performed on larynges of human fetuses in order to validate this model with aerodynamical experiments. Anatomical measurements were performed and a simplified numerical model was built using Fluent((R)) with the vocal folds in phonatory position. The results obtained are in good agreement with those obtained by laser Doppler velocimetry (LDV) and high-frame rate particle image velocimetry (HFR-PIV), on an experimental bench with excised human fetus larynges. It appears that computing with first cry physiological parameters leads to a model which is close to those obtained in experiments with real organs.

  1. Waste Isolation Pilot Plant transuranic wastes experimental characterization program: executive summary

    International Nuclear Information System (INIS)

    Molecke, M.A.

    1978-11-01

    A general overview of the Waste Isolation Pilot Plant transuranic wastes experimental characterization program is presented. Objectives and outstanding concerns of this program are discussed. Characteristics of transuranic wastes are also described. Concerns for the terminal isolation of such wastes in a deep bedded salt facility are divided into two phases, those during the short-term operational phase of the facility, and those potentially occurring in the long-term, after decommissioning of the repository. An inclusive summary covering individual studies, their importance to the Waste Isolation Pilot Plant, investigators, general milestones, and comments are presented

  2. Experimental characterisation and modelling of deformation- induced microstructure in an A6061 aluminium alloy

    International Nuclear Information System (INIS)

    Kreyca, J F; Falahati, A; Kozeschnik, E

    2016-01-01

    For industry, the mechanical properties of a material in form of flow curves are essential input data for finite element simulations. Current practice is to obtain flow curves experimentally and to apply fitting procedures to obtain constitutive equations that describe the material response to external loading as a function of temperature and strain rate. Unfortunately, the experimental procedure for characterizing flow curves is complex and expensive, which is why the prediction of flow-curves by computer modelling becomes increasingly important. In the present work, we introduce a state parameter based model that is capable of predicting the flow curves of an A6061 aluminium alloy in different heat-treatment conditions. The model is implemented in the thermo-kinetic software package MatCalc and takes into account precipitation kinetics, subgrain formation, dynamic recovery by spontaneous annihilation and dislocation climb. To validate the simulation results, a series of compression tests is performed on the thermo-mechanical simulator Gleeble 1500. (paper)

  3. Experimental characterisation and modelling of deformation- induced microstructure in an A6061 aluminium alloy

    Science.gov (United States)

    Kreyca, J. F.; Falahati, A.; Kozeschnik, E.

    2016-03-01

    For industry, the mechanical properties of a material in form of flow curves are essential input data for finite element simulations. Current practice is to obtain flow curves experimentally and to apply fitting procedures to obtain constitutive equations that describe the material response to external loading as a function of temperature and strain rate. Unfortunately, the experimental procedure for characterizing flow curves is complex and expensive, which is why the prediction of flow-curves by computer modelling becomes increasingly important. In the present work, we introduce a state parameter based model that is capable of predicting the flow curves of an A6061 aluminium alloy in different heat-treatment conditions. The model is implemented in the thermo-kinetic software package MatCalc and takes into account precipitation kinetics, subgrain formation, dynamic recovery by spontaneous annihilation and dislocation climb. To validate the simulation results, a series of compression tests is performed on the thermo-mechanical simulator Gleeble 1500.

  4. Experimental Damage Identification of a Model Reticulated Shell

    Directory of Open Access Journals (Sweden)

    Jing Xu

    2017-04-01

    Full Text Available The damage identification of a reticulated shell is a challenging task, facing various difficulties, such as the large number of degrees of freedom (DOFs, the phenomenon of modal localization and transition, and low modeling accuracy. Based on structural vibration responses, the damage identification of a reticulated shell was studied. At first, the auto-regressive (AR time series model was established based on the acceleration responses of the reticulated shell. According to the changes in the coefficients of the AR model between the damaged conditions and the undamaged condition, the damage of the reticulated shell can be detected. In addition, the damage sensitive factors were determined based on the coefficients of the AR model. With the damage sensitive factors as the inputs and the damage positions as the outputs, back-propagation neural networks (BPNNs were then established and were trained using the Levenberg–Marquardt algorithm (L–M algorithm. The locations of the damages can be predicted by the back-propagation neural networks. At last, according to the experimental scheme of single-point excitation and multi-point responses, the impact experiments on a K6 shell model with a scale of 1/10 were conducted. The experimental results verified the efficiency of the proposed damage identification method based on the AR time series model and back-propagation neural networks. The proposed damage identification method can ensure the safety of the practical engineering to some extent.

  5. Target Soil Impact Verification: Experimental Testing and Kayenta Constitutive Modeling.

    Energy Technology Data Exchange (ETDEWEB)

    Broome, Scott Thomas [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Flint, Gregory Mark [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Dewers, Thomas [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Newell, Pania [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States)

    2015-11-01

    This report details experimental testing and constitutive modeling of sandy soil deformation under quasi - static conditions. This is driven by the need to understand constitutive response of soil to target/component behavior upon impact . An experimental and constitutive modeling program was followed to determine elastic - plastic properties and a compressional failure envelope of dry soil . One hydrostatic, one unconfined compressive stress (UCS), nine axisymmetric compression (ACS) , and one uniaxial strain (US) test were conducted at room temperature . Elastic moduli, assuming isotropy, are determined from unload/reload loops and final unloading for all tests pre - failure and increase monotonically with mean stress. Very little modulus degradation was discernable from elastic results even when exposed to mean stresses above 200 MPa . The failure envelope and initial yield surface were determined from peak stresses and observed onset of plastic yielding from all test results. Soil elasto - plastic behavior is described using the Brannon et al. (2009) Kayenta constitutive model. As a validation exercise, the ACS - parameterized Kayenta model is used to predict response of the soil material under uniaxial strain loading. The resulting parameterized and validated Kayenta model is of high quality and suitable for modeling sandy soil deformation under a range of conditions, including that for impact prediction.

  6. WWER reactor fuel performance, modelling and experimental support. Proceedings

    International Nuclear Information System (INIS)

    Stefanova, S.; Chantoin, P.; Kolev, I.

    1994-01-01

    This publication is a compilation of 36 papers presented at the International Seminar on WWER Reactor Fuel Performance, Modelling and Experimental Support, organised by the Institute for Nuclear Research and Nuclear Energy (BG), in cooperation with the International Atomic Energy Agency. The Seminar was attended by 76 participants from 16 countries, including representatives of all major Russian plants and institutions responsible for WWER reactor fuel manufacturing, design and research. The reports are grouped in four chapters: 1) WWER Fuel Performance and Economics: Status and Improvement Prospects: 2) WWER Fuel Behaviour Modelling and Experimental Support; 3) Licensing of WWER Fuel and Fuel Analysis Codes; 4) Spent Fuel of WWER Plants. The reports from the corresponding four panel discussion sessions are also included. All individual papers are recorded in INIS as separate items

  7. WWER reactor fuel performance, modelling and experimental support. Proceedings

    Energy Technology Data Exchange (ETDEWEB)

    Stefanova, S; Chantoin, P; Kolev, I [eds.

    1994-12-31

    This publication is a compilation of 36 papers presented at the International Seminar on WWER Reactor Fuel Performance, Modelling and Experimental Support, organised by the Institute for Nuclear Research and Nuclear Energy (BG), in cooperation with the International Atomic Energy Agency. The Seminar was attended by 76 participants from 16 countries, including representatives of all major Russian plants and institutions responsible for WWER reactor fuel manufacturing, design and research. The reports are grouped in four chapters: (1) WWER Fuel Performance and Economics: Status and Improvement Prospects: (2) WWER Fuel Behaviour Modelling and Experimental Support; (3) Licensing of WWER Fuel and Fuel Analysis Codes; (4) Spent Fuel of WWER Plants. The reports from the corresponding four panel discussion sessions are also included. All individual papers are recorded in INIS as separate items.

  8. An Interactive Multimedia Based Instruction in Experimental Modelling

    DEFF Research Database (Denmark)

    Knudsen, Morten; Nielsen, J.N.; Østergaard, J.

    1997-01-01

    A CD-ROM based interactive multimedia instruction in experimental modelling for Danish Engineering School teachers is described. The content is based on a new sensitivity approach for direct estimation of physical parameters in linear and nonlinear dynamic systems. The presentation is inspired of...... of Solomans=s inventory of learning styles. To enhance active learning and motivation by real life problems, the simulation tool Matlab is integrated in the authoring program Medi8or....

  9. Numerical modeling of nitrogen oxide emission and experimental verification

    Directory of Open Access Journals (Sweden)

    Szecowka Lech

    2003-12-01

    Full Text Available The results of nitrogen reduction in combustion process with application of primary method are presented in paper. The reduction of NOx emission, by the recirculation of combustion gasses, staging of fuel and of air was investigated, and than the reduction of NOx emission by simultaneous usage of the mentioned above primary method with pulsatory disturbances.The investigations contain numerical modeling of NOx reduction and experimental verification of obtained numerical calculation results.

  10. Experimental model of cutaneous radiation injury in rabbits

    Energy Technology Data Exchange (ETDEWEB)

    Meirelles, Rafael Panisi de Campos [Universidade Federal de Sao Paulo (EPM/UNIFESP), SP (Brazil). Escola Paulista de Medicina; Hochman, Bernardo [Universidade Federal de Sao Paulo (EPM/UNIFESP), SP (Brazil). Escola Paulista de Medicina. Dept. de Cirurgia; Helene Junior, Americo; Fraga, Murillo Francisco Pires [Faculdade de Ciencias Medicas da Santa Casa de Sao Paulo (FCMSCSP), SP (Brazil). Dept. de Cirurgia. Divisao de Cirurgia Plastica; Lellis, Rute [Faculdade de Ciencias Medicas da Santa Casa de Sao Paulo (FCMSCSP), SP (Brazil). Divisao de Patologia; Ferreira, Lydia Masako, E-mail: rpcmeirelles@yahoo.com.br, E-mail: lydia.dcir@epm.br [Universidade Federal de Sao Paulo (EPM/UNIFESP), SP (Brazil). Escola Paulista de Mediciana. Divisao de Cirugia Plastica

    2013-07-01

    Purpose: to describe an experimental model of cutaneous radiation injury in rabbits. Methods: on this study eight six-month-old New Zealand male rabbits, with an average weight of 2.5kg were used. They were distributed in four groups (n=2 per group). The control group did not receive radiotherapy and the others received one radiotherapy session of 2000, 3000 and 4500 cGy, respectively. Photographic analysis and histopathological evaluation of the irradiated areas were carried out. Results: after 30 days, the animals from the control group had all their hair grown. In spite of that, the animals from group 2000 cGy had a 60-day alopecia and from group 3000 cGy, a 90-day alopecia. After the 30th day, the 3000cGy group demonstrated 90-day cutaneous radiation injuries, graded 3 and 4. One of the animals from group 4500 cGy died on the 7th day with visceral necrosis. The other from the same group had total skin necrosis. A progressive reduction of glands and blood vessels count and an increase on collagen deposition was observed. Conclusion: The proposed experimental model is reproducible. This study suggests that the dosage 4500cGy is excessive and the 3000 cGy is the most effective for this experimental model of cutaneous radiation injury in rabbits. (author)

  11. An experimental and kinetic modeling study of glycerol pyrolysis

    International Nuclear Information System (INIS)

    Fantozzi, F.; Frassoldati, A.; Bartocci, P.; Cinti, G.; Quagliarini, F.; Bidini, G.; Ranzi, E.M.

    2016-01-01

    Highlights: • Glycerol pyrolysis can produce about 44–48%v hydrogen at 750–800 °C. • A simplified 452 reactions kinetic model of glycerol pyrolysis has been developed. • The model has good agreement with experimental data. • Non condensable gas yields can reach 70%. - Abstract: Pyrolysis of glycerol, a by-product of the biodiesel industry, is an important potential source of hydrogen. The obtained high calorific value gas can be used either as a fuel for combined heat and power (CHP) generation or as a transportation fuel (for example hydrogen to be used in fuel cells). Optimal process conditions can improve glycerol pyrolysis by increasing gas yield and hydrogen concentration. A detailed kinetic mechanism of glycerol pyrolysis, which involves 137 species and more than 4500 reactions, was drastically simplified and reduced to a new skeletal kinetic scheme of 44 species, involved in 452 reactions. An experimental campaign with a batch pyrolysis reactor was properly designed to further validate the original and the skeletal mechanisms. The comparisons between model predictions and experimental data strongly suggest the presence of a catalytic process promoting steam reforming of methane. High pyrolysis temperatures (750–800 °C) improve process performances and non-condensable gas yields of 70%w can be achieved. Hydrogen mole fraction in pyrolysis gas is about 44–48%v. The skeletal mechanism developed can be easily used in Computational Fluid Dynamic software, reducing the simulation time.

  12. Survey of experimental tests of the IBA model

    International Nuclear Information System (INIS)

    Casten, R.F.

    1980-01-01

    A survey of experimental tests of the Interacting Boson Approximation (IBA) Model is presented covering even and odd mass nuclei in the region from A approx. 80 to A approx. 230. Both positive and negative parity states with both high and low spin are discussed. Topics included concern energy levels, electromagnetic transition rates, two nucleon transfer and inelastic scattering. Special attention is given to nuclear symmetries and transitional regions. Comparison with other models is made where appropriate. The distinction between IBA-1 and IBA-2 is discussed including their respective areas of applicability

  13. Dynamic Modeling of Wind Turbine Gearboxes and Experimental Validation

    DEFF Research Database (Denmark)

    Pedersen, Rune

    Grinding corrections are often applied to gear teeth, which will alter the load distribution across the tooth. Grinding corrections will also change the load sharing between neighboring tooth pairs, and in turn the gear mesh stiffness. In this thesis, a model for calculating the gear mesh stiffness...... is presented. The model takes into account the effects of load and applied grinding corrections. The results are verified by comparing to simulated and experimental results reported in the existing literature. Using gear data loosely based on a 1 MW wind turbine gearbox, the gear mesh stiffness is expanded...

  14. Finite element modeling and experimentation of bone drilling forces

    International Nuclear Information System (INIS)

    Lughmani, W A; Bouazza-Marouf, K; Ashcroft, I

    2013-01-01

    Bone drilling is an essential part of many orthopaedic surgery procedures, including those for internal fixation and for attaching prosthetics. Estimation and control of bone drilling forces are critical to prevent drill breakthrough, excessive heat generation, and mechanical damage to the bone. This paper presents a 3D finite element (FE) model for prediction of thrust forces experienced during bone drilling. The model incorporates the dynamic characteristics involved in the process along with the accurate geometrical considerations. The average critical thrust forces and torques obtained using FE analysis, for set of machining parameters are found to be in good agreement with the experimental results

  15. Experimental Method for Characterizing Electrical Steel Sheets in the Normal Direction

    Directory of Open Access Journals (Sweden)

    Thierry Belgrand

    2010-10-01

    Full Text Available This paper proposes an experimental method to characterise magnetic laminations in the direction normal to the sheet plane. The principle, which is based on a static excitation to avoid planar eddy currents, is explained and specific test benches are proposed. Measurements of the flux density are made with a sensor moving in and out of an air-gap. A simple analytical model is derived in order to determine the permeability in the normal direction. The experimental results for grain oriented steel sheets are presented and a comparison is provided with values obtained from literature.

  16. Ultraviolet radiation-induced carcinogenesis: mechanisms and experimental models

    International Nuclear Information System (INIS)

    Ramasamy, Karthikeyan; Shanmugam, Mohana; Balupillai, Agilan; Govindhasamy, Kanimozhi; Gunaseelan, Srithar; Muthusamy, Ganesan; Robert, Beualah Mary; Nagarajan, Rajendra Prasad

    2017-01-01

    Ultraviolet radiation (UVR) is a very prominent environmental toxic agent. UVR has been implicated in the initiation and progression of photocarcinogenesis. UVR exposure elicits numerous cellular and molecular events which include the generation of inflammatory mediators, DNA damage, epigenetic modifications, and oxidative damages mediated activation of signaling pathways. UVR-initiated signal transduction pathways are believed to be responsible for tumor promotion effects. UVR-induced carcinogenic mechanism has been well studied using various animal and cellular models. Human skin-derived dermal fibroblasts, epidermal keratinocytes, and melanocytes served as excellent cellular model systems for the understanding of UVR-mediated carcinogenic events. Apart from this, scientists developed reconstituted three-dimensional normal human skin equivalent models for the study of UVR signaling pathways. Moreover, hairless mice such as SKH-1, devoid of Hr gene, served as a valuable model for experimental carcinogenesis. Scientists have also used transgenic mice and dorsal portion shaved Swiss albino mice for UVR carcinogenesis studies. In this review, we have discussed the current progress in the study on ultraviolet B (UVB)-mediated carcinogenesis and outlined appropriate experimental models for both ultraviolet A- and UVB-mediated carcinogenesis. (author)

  17. Waste glass corrosion modeling: Comparison with experimental results

    International Nuclear Information System (INIS)

    Bourcier, W.L.

    1993-11-01

    A chemical model of glass corrosion will be used to predict the rates of release of radionuclides from borosilicate glass waste forms in high-level waste repositories. The model will be used both to calculate the rate of degradation of the glass, and also to predict the effects of chemical interactions between the glass and repository materials such as spent fuel, canister and container materials, backfill, cements, grouts, and others. Coupling between the degradation processes affecting all these materials is expected. Models for borosilicate glass dissolution must account for the processes of (1) kinetically-controlled network dissolution, (2) precipitation of secondary phases, (3) ion exchange, (4) rate-limiting diffusive transport of silica through a hydrous surface reaction layer, and (5) specific glass surface interactions with dissolved cations and anions. Current long-term corrosion models for borosilicate glass employ a rate equation consistent with transition state theory embodied in a geochemical reaction-path modeling program that calculates aqueous phase speciation and mineral precipitation/dissolution. These models are currently under development. Future experimental and modeling work to better quantify the rate-controlling processes and validate these models are necessary before the models can be used in repository performance assessment calculations

  18. Structures under crash and impact continuum mechanics, discretization and experimental characterization

    CERN Document Server

    Hiermaier, Stefan

    2007-01-01

    Required reading for those in the relevant areas of work, this book examines the testing and modeling of materials and structures under dynamic loading conditions.Readers get an in-depth analysis of the current mathematical modeling and simulation tools available for a variety of materials, alongside discussions of the benefits and limitations these tools pose in industrial design.The models discussed are also available in commercial codes such as LS-DYNA and AOTODYN.Following a logical and well organized structure, this volume uniquely combines experimental procedures with numerical simulatio

  19. Experimental evaluation of analytical penumbra calculation model for wobbled beams

    International Nuclear Information System (INIS)

    Kohno, Ryosuke; Kanematsu, Nobuyuki; Yusa, Ken; Kanai, Tatsuaki

    2004-01-01

    The goal of radiotherapy is not only to apply a high radiation dose to a tumor, but also to avoid side effects in the surrounding healthy tissue. Therefore, it is important for carbon-ion treatment planning to calculate accurately the effects of the lateral penumbra. In this article, for wobbled beams under various irradiation conditions, we focus on the lateral penumbras at several aperture positions of one side leaf of the multileaf collimator. The penumbras predicted by an analytical penumbra calculation model were compared with the measured results. The results calculated by the model for various conditions agreed well with the experimental ones. In conclusion, we found that the analytical penumbra calculation model could predict accurately the measured results for wobbled beams and it was useful for carbon-ion treatment planning to apply the model

  20. Numerical calibration and experimental validation of a PCM-Air heat exchanger model

    International Nuclear Information System (INIS)

    Stathopoulos, N.; El Mankibi, M.; Santamouris, Mattheos

    2017-01-01

    Highlights: • Development of a PCM-Air heat exchanger experimental unit and its numerical model. • Differential Scanning Calorimetry for PCM properties. • Ineptitude of DSC obtained heat capacity curves. • Creation of adequate heat capacity curves depending on heat transfer rates. • Confrontation of numerical and experimental results and validation of the model. - Abstract: Ambitious goals have been set at international, European and French level for energy consumption and greenhouse gas emissions decrease of the building sector. Achieving them requires renewable energy integration, a technology that presents however an important drawback: intermittent energy production. In response, thermal energy storage (TES) technology applications have been developed in order to correlate energy production and consumption of the building. Phase Change Materials (PCMs) have been widely used in TES applications as they offer a high storage density and adequate phase change temperature range. It is important to accurately know the thermophysical properties of the PCM, both for experimental (system design) and numerical (correct prediction) purposes. In this paper, the fabrication of a PCM – Air experimental prototype is presented at first, along with the development of a numerical model simulating the downstream temperature evolution of the heat exchanger. Particular focus is given to the calibration method and the validation of the model using experimental characterization results. Differential scanning calorimetry (DSC) is used to define the thermal properties of the PCM. Initial numerical results are underestimated compared to experimental ones. Various factors were investigated, pointing to the ineptitude of the heat capacity parameter, as DSC results depend on heating/cooling rates. Adequate heat capacity curves were empirically determined, depending on heat transfer rates and based on DSC results and experimental observations. The results of the proposed model

  1. A new dietary model to study colorectal carcinogenesis: experimental design, food preparation, and experimental findings.

    Science.gov (United States)

    Rozen, P; Liberman, V; Lubin, F; Angel, S; Owen, R; Trostler, N; Shkolnik, T; Kritchevsky, D

    1996-01-01

    Experimental dietary studies of human colorectal carcinogenesis are usually based on the AIN-76A diet, which is dissimilar to human food in source, preparation, and content. The aims of this study were to examine the feasibility of preparing and feeding rats the diet of a specific human population at risk for colorectal neoplasia and to determine whether changes in the colonic morphology and metabolic contents would differ from those resulting from a standard rat diet. The mean daily food intake composition of a previously evaluated adenoma patient case-control study was used for the "human adenoma" (HA) experimental diet. Foods were prepared as for usual human consumption and processed by dehydration to the physical characteristics of an animal diet. Sixty-four female Sprague-Dawley rats were randomized and fed ad libitum the HA or the AIN-76A diet. Every eight weeks, eight rats from each group were sacrificed, and the colons and contents were examined. Analysis of the prepared food showed no significant deleterious changes; food intake and weight gain were similar in both groups. Compared with the controls, the colonic contents of rats fed the HA diet contained significantly less calcium, concentrations of neutral sterols, total lipids, and cholic and deoxycholic acids were increased, and there were no colonic histological changes other than significant epithelial hyperproliferation. This initial study demonstrated that the HA diet can be successfully processed for feeding to experimental animals and is acceptable and adequate for growth but induces significant metabolic and hyperproliferative changes in the rat colon. This dietary model may be useful for studies of human food, narrowing the gap between animal experimentation and human nutritional research.

  2. Experimental and Numerical Characterization of a Pulsed Supersonic Uniform Flow for Kinetics and Spectroscopy

    Science.gov (United States)

    Suas-David, Nicolas; Thawoos, Shameemah; Broderick, Bernadette M.; Suits, Arthur

    2017-06-01

    The current CPUF (Chirped Pulse Uniform Flow) and the new UF-CRDS (Uniform Flow Cavity Ring-Down Spectroscopy) setups relie mostly on the production of a good quality supersonic uniform flow. A supersonic uniform flow is produced by expanding a gas through a Laval nozzle - similar to the nozzles used in aeronautics - linked to a vacuum chamber. The expansion is characterized by an isentropic core where constant very low kinetic temperature (down to 20K) and constant density are observed. The relatively large diameter of the isentropic core associated with homogeneous thermodynamic conditions makes it a relevant tool for low temperature spectroscopy. On the other hand, the length along the axis of the flow of this core (could be longer than 50cm) allows kinetic studies which is one of the main interest of this setup (CRESU technique. The formation of a uniform flow requires an extreme accuracy in the design of the shape of the nozzle for a set of defined temperature/density. The design is based on a Matlab program which retrieves the shape of the isentropic core according to the method of characteristics prior to calculate the thickness of the boundary layer. Two different approaches are used to test the viability of a new nozzle derived from the program. First, a computational fluid dynamic software (OpenFOAM) models the distribution of the thermodynamic properties of the expansion. Then, fabricated nozzles using 3-D printing are tested based on Pitot measurements and spectroscopic analyses. I will present comparisons of simulation and measured performance for a range of nozzles. We will see how the high level of accuracy of numerical simulations provides a deeper knowledge of the experimental conditions. J. M. Oldham, C. Abeysekera, J. Joalland, L. N. Zack, K. Prozument, I. R. Sims, G. Barrat Park, R. W. Filed and A. G. Suits, J. Chem. Phys. 141, 154202, (2014). I. Sims, J. L. Queffelec, A. Defrance, C. Rebrion-Rowe, D. Travers, P. Bocherel, B. Rowe, I. W. Smith

  3. A Novel Experimental and Modelling Strategy for Nanoparticle Toxicity Testing Enabling the Use of Small Quantities

    Directory of Open Access Journals (Sweden)

    Marinda van Pomeren

    2017-11-01

    Full Text Available Metallic nanoparticles (NPs differ from other metal forms with respect to their large surface to volume ratio and subsequent inherent reactivity. Each new modification to a nanoparticle alters the surface to volume ratio, fate and subsequently the toxicity of the particle. Newly-engineered NPs are commonly available only in low quantities whereas, in general, rather large amounts are needed for fate characterizations and effect studies. This challenge is especially relevant for those NPs that have low inherent toxicity combined with low bioavailability. Therefore, within our study, we developed new testing strategies that enable working with low quantities of NPs. The experimental testing method was tailor-made for NPs, whereas we also developed translational models based on different dose-metrics allowing to determine dose-response predictions for NPs. Both the experimental method and the predictive models were verified on the basis of experimental effect data collected using zebrafish embryos exposed to metallic NPs in a range of different chemical compositions and shapes. It was found that the variance in the effect data in the dose-response predictions was best explained by the minimal diameter of the NPs, whereas the data confirmed that the predictive model is widely applicable to soluble metallic NPs. The experimental and model approach developed in our study support the development of (ecotoxicity assays tailored to nano-specific features.

  4. Computational Fluid Dynamics Modeling of the Human Pulmonary Arteries with Experimental Validation.

    Science.gov (United States)

    Bordones, Alifer D; Leroux, Matthew; Kheyfets, Vitaly O; Wu, Yu-An; Chen, Chia-Yuan; Finol, Ender A

    2018-05-21

    Pulmonary hypertension (PH) is a chronic progressive disease characterized by elevated pulmonary arterial pressure, caused by an increase in pulmonary arterial impedance. Computational fluid dynamics (CFD) can be used to identify metrics representative of the stage of PH disease. However, experimental validation of CFD models is often not pursued due to the geometric complexity of the model or uncertainties in the reproduction of the required flow conditions. The goal of this work is to validate experimentally a CFD model of a pulmonary artery phantom using a particle image velocimetry (PIV) technique. Rapid prototyping was used for the construction of the patient-specific pulmonary geometry, derived from chest computed tomography angiography images. CFD simulations were performed with the pulmonary model with a Reynolds number matching those of the experiments. Flow rates, the velocity field, and shear stress distributions obtained with the CFD simulations were compared to their counterparts from the PIV flow visualization experiments. Computationally predicted flow rates were within 1% of the experimental measurements for three of the four branches of the CFD model. The mean velocities in four transversal planes of study were within 5.9 to 13.1% of the experimental mean velocities. Shear stresses were qualitatively similar between the two methods with some discrepancies in the regions of high velocity gradients. The fluid flow differences between the CFD model and the PIV phantom are attributed to experimental inaccuracies and the relative compliance of the phantom. This comparative analysis yielded valuable information on the accuracy of CFD predicted hemodynamics in pulmonary circulation models.

  5. Experimental characterization of electrochemically polymerized polycarbazole film and study of its behavior with different metals contacts

    Science.gov (United States)

    Srivastava, Aditi; Chakrabarti, P.

    2017-12-01

    In this paper, we present the method of fabrication, experimental characterization, and comparison of electrical parameters of semiconducting polycarbazole film with different rectifying metals contacts. Electrochemical polymerization and deposition of organic semiconductor, i.e., polycarbazole on ITO-coated glass substrate, were performed using an electrochemical workstation. Experimental characterization of the prepared polymer film was done in respect of morphology, absorption, bandgap, and thickness. The stability and electro-activity of polycarbazole film were verified by the cyclic voltammetric method. Study of the behavior of prepared polycarbazole film with the different metals contacts such as Aluminum, Copper, Tungsten, and Tin has been done using semiconductor device analyzer. Various electrical parameters such as barrier height, ideality factor, and reverse saturation current have been extracted with different metal contacts, and the values were compared and contrasted. The nature of I- V characteristic of polycarbazole film in non-contact mode has also been analyzed using scanning tunneling microscope. The rectifying I- V characteristics obtained with different metals contacts have also been validated by the simulation on Deckbuild platform of the of ATLAS® software tool from Silvaco Inc.

  6. Concrete structures vulnerability under impact: characterization, modeling, and validation - Concrete slabs vulnerability under impact: characterization, modeling, and validation

    International Nuclear Information System (INIS)

    Xuan Dung Vu

    2013-01-01

    Concrete is a material whose behavior is complex, especially in cases of extreme loads. The objective of this thesis is to carry out an experimental characterization of the behavior of concrete under impact-generated stresses (confined compression and dynamic traction) and to develop a robust numerical tool to reliably model this behavior. In the experimental part, we have studied concrete samples from the VTT center (Technical Research Center of Finland). At first, quasi-static triaxial compressions with the confinement varies from 0 MPa (unconfined compression test) to 600 MPa were realized. The stiffness of the concrete increases with confinement pressure because of the reduction of porosity. Therefore, the maximum shear strength of the concrete is increased. The presence of water plays an important role when the degree of saturation is high and the concrete is subjected to high confinement pressure. Beyond a certain level of confinement pressure, the maximum shear strength of concrete decreases with increasing water content. The effect of water also influences the volumetric behavior of concrete. When all free pores are closed as a result of compaction, the low compressibility of the water prevents the deformation of the concrete, whereby the wet concrete is less deformed than the dry concrete for the same mean stress. The second part of the experimental program concerns dynamic tensile tests at different loading velocities, and different moisture conditions of concrete. The results show that the tensile strength of concrete C50 may increase up to 5 times compared to its static strength for a strain rate of about 100 s -1 . In the numerical part, we are interested in improving an existing constitutive coupled model of concrete behavior called PRM (Pontiroli-Rouquand-Mazars) to predict the concrete behavior under impact. This model is based on a coupling between a damage model which is able to describe the degradation mechanisms and cracking of the concrete at

  7. Experimental model of cultured keratinocytes Modelo experimental de cultura de queratinócitos

    Directory of Open Access Journals (Sweden)

    Alfredo Gragnani

    2003-01-01

    Full Text Available The bioengineering research is essential in the development of ideal combination of biomaterials and cultured cells to produce the permanent wound coverage. The experimental model of cultured keratinocytes presents all steps of the culture, since the isolation of the keratinocytes, preparation of the human acellular dermis, preparation of the composite skin graft and their elevation to the air-liquid interface. The research in cultured keratinocytes model advances in two main ways: 1. optimization of the methods in vitro to the skin cells culture and proliferation and 2. developing biomaterials that present similar skin properties.A pesquisa em bioengenharia é primordial no desenvolvimento da combinação ideal de biomateriais e células cultivadas para produzir a cobertura definitiva das lesões. O modelo experimental da cultura de queratinócitos apresenta toda as etapas do cultivo, desde o isolamento dos queratinócitos, preparação da derme acelular humana, do enxerto composto e da sua elevação à interface ar-líquido. A pesquisa em modelo de cultura de queratinócitos desenvolve-se em duas vias principais: 1. otimização dos métodos in vitro para cultivo e proliferação de células da pele e 2. desenvolvimento de biomateriais que mimetizem as propriedades da pele.

  8. DMFC anode polarization: Experimental analysis and model validation

    Energy Technology Data Exchange (ETDEWEB)

    Casalegno, A.; Marchesi, R. [Dipartimento di Energetica, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milano (Italy)

    2008-01-03

    Anode two-phase flow has an important influence on DMFC performance and methanol crossover. In order to elucidate two-phase flow influence on anode performance, in this work, anode polarization is investigated combining experimental and modelling approach. A systematic experimental analysis of operating conditions influence on anode polarization is presented. Hysteresis due to operating condition is observed; experimental results suggest that it arises from methanol accumulation and has to be considered in evaluating DMFC performances and measurements reproducibility. A model of DMFC anode polarization is presented and utilised as tool to investigate anode two-phase flow. The proposed analysis permits one to produce a confident interpretation of the main involved phenomena. In particular, it confirms that methanol electro-oxidation kinetics is weakly dependent on methanol concentration and that methanol transport in gas phase produces an important contribution in anode feeding. Moreover, it emphasises the possibility to optimise anode flow rate in order to improve DMFC performance and reduce methanol crossover. (author)

  9. Numerical modelling of negative discharges in air with experimental validation

    International Nuclear Information System (INIS)

    Tran, T N; Golosnoy, I O; Lewin, P L; Georghiou, G E

    2011-01-01

    Axisymmetric finite element models have been developed for the simulation of negative discharges in air without and with the presence of dielectrics. The models are based on the hydrodynamic drift-diffusion approximation. A set of continuity equations accounting for the movement, generation and loss of charge carriers (electrons, positive and negative ions) is coupled with Poisson's equation to take into account the effect of space and surface charges on the electric field. The model of a negative corona discharge (without dielectric barriers) in a needle-plane geometry is analysed first. The results obtained show good agreement with experimental observations for various Trichel pulse characteristics. With dielectric barriers introduced into the discharge system, the surface discharge exhibits some similarities and differences to the corona case. The model studies the dynamics of volume charge generation, electric field variations and charge accumulation over the dielectric surface. The predicted surface charge density is consistent with experimental results obtained from the Pockels experiment in terms of distribution form and magnitude.

  10. Modeling and experimental tests of a copper thermosyphon

    Directory of Open Access Journals (Sweden)

    Paulo Henrique Dias dos Santos

    2017-02-01

    Full Text Available Electrical energy, solar energy, and/or direct combustion of a fuel are the most common thermal sources for home water heating. In recent years, the use of solar energy has become popular because it is a renewable and economic energy source. Among the solar collectors, those assisted by thermosyphons are more efficient; therefore, they can enhance the heat transfer to water. A thermosyphon is basically a sealed tube filled with a working fluid and, normally, it has three regions: the evaporator, the adiabatic section and the condenser. The great advantage of this device is that the thermal resistance to heat transfer between its regions is very small, and as a result, there is a small temperature difference. This article aims to model a thermosyphon by using correlations based on its operation limits. This modeling will be used as a design tool for compact solar collectors assisted by thermosyphons. Based on the results obtained with the mathematical modeling, one copper thermosyphon, with deionized water as the working fluid, was developed and experimentally tested. The tests were carried out for a heat load varying from 30 to 60W in a vertical position. The theoretical and experimental results were compared to verify the mathematical model.

  11. An experimental and modeling study of diethyl carbonate oxidation

    KAUST Repository

    Nakamura, Hisashi; Curran, Henry J.; Polo-Có rdoba, Á ngel David; Pitz, William J.; Dagaut, P.; Togbé , Casimir; Sarathy, Mani; Mehl, Marco; Agudelo, John Ramiro; Bustamante, Felipe

    2015-01-01

    Diethyl carbonate (DEC) is an attractive biofuel that can be used to displace petroleum-derived diesel fuel, thereby reducing CO2 and particulate emissions from diesel engines. A better understanding of DEC combustion characteristics is needed to facilitate its use in internal combustion engines. Toward this goal, ignition delay times for DEC were measured at conditions relevant to internal combustion engines using a rapid compression machine (RCM) and a shock tube. The experimental conditions investigated covered a wide range of temperatures (660-1300K), a pressure of 30bar, and equivalence ratios of 0.5, 1.0 and 2.0 in air. To provide further understanding of the intermediates formed in DEC oxidation, species concentrations were measured in a jet-stirred reactor at 10atm over a temperature range of 500-1200K and at equivalence ratios of 0.5, 1.0 and 2.0. These experimental measurements were used to aid the development and validation of a chemical kinetic model for DEC.The experimental results for ignition in the RCM showed near negative temperature coefficient (NTC) behavior. Six-membered alkylperoxy radical (RO˙2) isomerizations are conventionally thought to initiate low-temperature branching reactions responsible for NTC behavior, but DEC has no such possible 6- and 7-membered ring isomerizations. However, its molecular structure allows for 5-, 8- and 9-membered ring RO˙2 isomerizations. To provide accurate rate constants for these ring structures, ab initio computations for RO˙2⇌Q˙OOH isomerization reactions were performed. These new RO˙2 isomerization rate constants have been implemented in a chemical kinetic model for DEC oxidation. The model simulations have been compared with ignition delay times measured in the RCM near the NTC region. Results of the simulation were also compared with experimental results for ignition in the high-temperature region and for species concentrations in the jet-stirred reactor. Chemical kinetic insights into the

  12. An experimental and modeling study of diethyl carbonate oxidation

    KAUST Repository

    Nakamura, Hisashi

    2015-04-01

    Diethyl carbonate (DEC) is an attractive biofuel that can be used to displace petroleum-derived diesel fuel, thereby reducing CO2 and particulate emissions from diesel engines. A better understanding of DEC combustion characteristics is needed to facilitate its use in internal combustion engines. Toward this goal, ignition delay times for DEC were measured at conditions relevant to internal combustion engines using a rapid compression machine (RCM) and a shock tube. The experimental conditions investigated covered a wide range of temperatures (660-1300K), a pressure of 30bar, and equivalence ratios of 0.5, 1.0 and 2.0 in air. To provide further understanding of the intermediates formed in DEC oxidation, species concentrations were measured in a jet-stirred reactor at 10atm over a temperature range of 500-1200K and at equivalence ratios of 0.5, 1.0 and 2.0. These experimental measurements were used to aid the development and validation of a chemical kinetic model for DEC.The experimental results for ignition in the RCM showed near negative temperature coefficient (NTC) behavior. Six-membered alkylperoxy radical (RO˙2) isomerizations are conventionally thought to initiate low-temperature branching reactions responsible for NTC behavior, but DEC has no such possible 6- and 7-membered ring isomerizations. However, its molecular structure allows for 5-, 8- and 9-membered ring RO˙2 isomerizations. To provide accurate rate constants for these ring structures, ab initio computations for RO˙2⇌Q˙OOH isomerization reactions were performed. These new RO˙2 isomerization rate constants have been implemented in a chemical kinetic model for DEC oxidation. The model simulations have been compared with ignition delay times measured in the RCM near the NTC region. Results of the simulation were also compared with experimental results for ignition in the high-temperature region and for species concentrations in the jet-stirred reactor. Chemical kinetic insights into the

  13. Experimental characterization of a concentrating photovoltaic system varying the light concentration

    International Nuclear Information System (INIS)

    Renno, C.; Petito, F.; Landi, G.; Neitzert, H.C.

    2017-01-01

    Highlights: • Experimental characterization of a concentrating photovoltaic system. • Analysis of the point-focus concentrating system performances. • Photovoltaic system parameters as function of the concentration factor. - Abstract: The concentrating photovoltaic system represents one of the most promising solar technologies because it allows a more efficient energy conversion. When a CPV system is designed, the main parameter which has to be considered is the concentration factor that affects both the system energy performances and its configuration. An experimental characterization of a CPV system previously realized at the University of Salerno, is presented in this paper considering several aspects related to the optical configuration, the concentration factor and the solar cell used. In particular, the parameters of an Indium Gallium Phosphide/Gallium Arsenide/Germanium triple-junction solar cell are investigated as function of the concentration factor determined by means of an experimental procedure that uses different optical configurations. The maximum concentration factor reached by the CPV system is 310 suns. The cell parameters dependence on the concentration is reported together with an electroluminescence analysis of the Indium Gallium Phosphide/Gallium Arsenide/Germanium cell. A monitoring of the electrical power provided by the system during its working is also presented corresponding to different direct irradiance values. A mean power of 2.95 W with an average efficiency of 32.8% is obtained referring to a mean irradiance of 930 W/m"2; lower values are obtained when the irradiance is highly fluctuating. The concentrating photovoltaic system electric energy output is estimated considering different concentration levels; the maximal obtained value is 23.5 W h on a sunny day at 310×. Finally, the temperature of the triple-junction solar cell is evaluated for different months in order to evaluate the potential annual thermal energy production

  14. Developing a laser shockwave model for characterizing diffusion bonded interfaces

    International Nuclear Information System (INIS)

    Lacy, Jeffrey M.; Smith, James A.; Rabin, Barry H.

    2015-01-01

    The US National Nuclear Security Agency has a Global Threat Reduction Initiative (GTRI) with the goal of reducing the worldwide use of high-enriched uranium (HEU). A salient component of that initiative is the conversion of research reactors from HEU to low enriched uranium (LEU) fuels. An innovative fuel is being developed to replace HEU in high-power research reactors. The new LEU fuel is a monolithic fuel made from a U-Mo alloy foil encapsulated in Al-6061 cladding. In order to support the fuel qualification process, the Laser Shockwave Technique (LST) is being developed to characterize the clad-clad and fuel-clad interface strengths in fresh and irradiated fuel plates. LST is a non-contact method that uses lasers for the generation and detection of large amplitude acoustic waves to characterize interfaces in nuclear fuel plates. However, because the deposition of laser energy into the containment layer on a specimen's surface is intractably complex, the shock wave energy is inferred from the surface velocity measured on the backside of the fuel plate and the depth of the impression left on the surface by the high pressure plasma pulse created by the shock laser. To help quantify the stresses generated at the interfaces, a finite element method (FEM) model is being utilized. This paper will report on initial efforts to develop and validate the model by comparing numerical and experimental results for back surface velocities and front surface depressions in a single aluminum plate representative of the fuel cladding

  15. Developing a laser shockwave model for characterizing diffusion bonded interfaces

    Energy Technology Data Exchange (ETDEWEB)

    Lacy, Jeffrey M., E-mail: Jeffrey.Lacy@inl.gov; Smith, James A., E-mail: Jeffrey.Lacy@inl.gov; Rabin, Barry H., E-mail: Jeffrey.Lacy@inl.gov [Idaho National Laboratory, Idaho Falls, ID (United States)

    2015-03-31

    The US National Nuclear Security Agency has a Global Threat Reduction Initiative (GTRI) with the goal of reducing the worldwide use of high-enriched uranium (HEU). A salient component of that initiative is the conversion of research reactors from HEU to low enriched uranium (LEU) fuels. An innovative fuel is being developed to replace HEU in high-power research reactors. The new LEU fuel is a monolithic fuel made from a U-Mo alloy foil encapsulated in Al-6061 cladding. In order to support the fuel qualification process, the Laser Shockwave Technique (LST) is being developed to characterize the clad-clad and fuel-clad interface strengths in fresh and irradiated fuel plates. LST is a non-contact method that uses lasers for the generation and detection of large amplitude acoustic waves to characterize interfaces in nuclear fuel plates. However, because the deposition of laser energy into the containment layer on a specimen's surface is intractably complex, the shock wave energy is inferred from the surface velocity measured on the backside of the fuel plate and the depth of the impression left on the surface by the high pressure plasma pulse created by the shock laser. To help quantify the stresses generated at the interfaces, a finite element method (FEM) model is being utilized. This paper will report on initial efforts to develop and validate the model by comparing numerical and experimental results for back surface velocities and front surface depressions in a single aluminum plate representative of the fuel cladding.

  16. A hierarchy of models for simulating experimental results from a 3D heterogeneous porous medium

    Science.gov (United States)

    Vogler, Daniel; Ostvar, Sassan; Paustian, Rebecca; Wood, Brian D.

    2018-04-01

    In this work we examine the dispersion of conservative tracers (bromide and fluorescein) in an experimentally-constructed three-dimensional dual-porosity porous medium. The medium is highly heterogeneous (σY2 = 5.7), and consists of spherical, low-hydraulic-conductivity inclusions embedded in a high-hydraulic-conductivity matrix. The bimodal medium was saturated with tracers, and then flushed with tracer-free fluid while the effluent breakthrough curves were measured. The focus for this work is to examine a hierarchy of four models (in the absence of adjustable parameters) with decreasing complexity to assess their ability to accurately represent the measured breakthrough curves. The most information-rich model was (1) a direct numerical simulation of the system in which the geometry, boundary and initial conditions, and medium properties were fully independently characterized experimentally with high fidelity. The reduced-information models included; (2) a simplified numerical model identical to the fully-resolved direct numerical simulation (DNS) model, but using a domain that was one-tenth the size; (3) an upscaled mobile-immobile model that allowed for a time-dependent mass-transfer coefficient; and, (4) an upscaled mobile-immobile model that assumed a space-time constant mass-transfer coefficient. The results illustrated that all four models provided accurate representations of the experimental breakthrough curves as measured by global RMS error. The primary component of error induced in the upscaled models appeared to arise from the neglect of convection within the inclusions. We discuss the necessity to assign value (via a utility function or other similar method) to outcomes if one is to further select from among model options. Interestingly, these results suggested that the conventional convection-dispersion equation, when applied in a way that resolves the heterogeneities, yields models with high fidelity without requiring the imposition of a more

  17. Modeling an Excitable Biosynthetic Tissue with Inherent Variability for Paired Computational-Experimental Studies.

    Directory of Open Access Journals (Sweden)

    Tanmay A Gokhale

    2017-01-01

    Full Text Available To understand how excitable tissues give rise to arrhythmias, it is crucially necessary to understand the electrical dynamics of cells in the context of their environment. Multicellular monolayer cultures have proven useful for investigating arrhythmias and other conduction anomalies, and because of their relatively simple structure, these constructs lend themselves to paired computational studies that often help elucidate mechanisms of the observed behavior. However, tissue cultures of cardiomyocyte monolayers currently require the use of neonatal cells with ionic properties that change rapidly during development and have thus been poorly characterized and modeled to date. Recently, Kirkton and Bursac demonstrated the ability to create biosynthetic excitable tissues from genetically engineered and immortalized HEK293 cells with well-characterized electrical properties and the ability to propagate action potentials. In this study, we developed and validated a computational model of these excitable HEK293 cells (called "Ex293" cells using existing electrophysiological data and a genetic search algorithm. In order to reproduce not only the mean but also the variability of experimental observations, we examined what sources of variation were required in the computational model. Random cell-to-cell and inter-monolayer variation in both ionic conductances and tissue conductivity was necessary to explain the experimentally observed variability in action potential shape and macroscopic conduction, and the spatial organization of cell-to-cell conductance variation was found to not impact macroscopic behavior; the resulting model accurately reproduces both normal and drug-modified conduction behavior. The development of a computational Ex293 cell and tissue model provides a novel framework to perform paired computational-experimental studies to study normal and abnormal conduction in multidimensional excitable tissue, and the methodology of modeling

  18. Experimental investigations and modelling of sodium-concrete interaction

    International Nuclear Information System (INIS)

    Schultheiss, G.F.; Deeg, H.J.

    1990-01-01

    The use of sodium as a coolant in liquid metal fast breeder reactors, fusion reactors, and solar plants requires special consideration of its chemical reactivity and related safety problems in the case of sodium leckage. On contact between hot sodium and concrete an interaction takes place resulting in energy release and hydrogen generation, which may contribute to containment loading by pressurization in a hypothetical accident situation. For this reason, sodium-concrete interactions were investigated experimentally and theoretically. The experiments revealed important effects of quartzitic material within the concrete and of the sodium temperature on the interaction mechanisms, the energy release and the consequent hydrogen production. The numerical model shows good agreement with the experimental results. (orig.) [de

  19. Numerical modeling and experimental validation of thermoplastic composites induction welding

    Science.gov (United States)

    Palmieri, Barbara; Nele, Luigi; Galise, Francesco

    2018-05-01

    In this work, a numerical simulation and experimental test of the induction welding of continuous fibre-reinforced thermoplastic composites (CFRTPCs) was provided. The thermoplastic Polyamide 66 (PA66) with carbon fiber fabric was used. Using a dedicated software (JMag Designer), the influence of the fundamental process parameters such as temperature, current and holding time was investigated. In order to validate the results of the simulations, and therefore the numerical model used, experimental tests were carried out, and the temperature values measured during the tests were compared with the aid of an optical pyrometer, with those provided by the numerical simulation. The mechanical properties of the welded joints were evaluated by single lap shear tests.

  20. Experimental limits from ATLAS on Standard Model Higgs production.

    CERN Multimedia

    ATLAS, collaboration

    2012-01-01

    Experimental limits from ATLAS on Standard Model Higgs production in the mass range 110-600 GeV. The solid curve reflects the observed experimental limits for the production of a Higgs of each possible mass value (horizontal axis). The region for which the solid curve dips below the horizontal line at the value of 1 is excluded with a 95% confidence level (CL). The dashed curve shows the expected limit in the absence of the Higgs boson, based on simulations. The green and yellow bands correspond (respectively) to 68%, and 95% confidence level regions from the expected limits. Higgs masses in the narrow range 123-130 GeV are the only masses not excluded at 95% CL

  1. Characterization of nanotransistors in a semiempirical model

    Czech Academy of Sciences Publication Activity Database

    Wulf, U.; Kučera, Jan; Richter, H.; Wiatr, M.; Höntschel, J.

    2016-01-01

    Roč. 613, Aug (2016), s. 6-10 ISSN 0040-6090 Institutional support: RVO:68378271 Keywords : nano-field effect transistor * quantum transport * semiempirical model * quantitative model * compact model * contact-channel coupling * screening propertie Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.879, year: 2016

  2. Experimental model of the burn wound topical treatment

    Directory of Open Access Journals (Sweden)

    Amra Čabaravdić

    2003-11-01

    Full Text Available AbstractBACKGROUND AND PURPOSE:Clinical research of drugs is a researching step subsequent to the preclinical studies in experimental animals. The aim of our research was to evaluate animal model of wound healing process after the burninducement and effects of the ointment containing natural plants on the process of burn healing.MATERIAL AND METHODS:Burn wounds were experimentally induced in two species of experimental animals which were treated with topically applied herbal preparation with concomitant monitoring of the healing process. Experimental groups (1 of 15 animals each (mice and rats, while control group (2 of 10 animals each (mice and rats that were not being treated with herbal ointment. After the hair removal, burn was induced on the back of animals by heated brass seal. Different clinical symptoms including oedema of surrounding tissue, redness, exudation, size of the burn surface, histological and microbiological findings were monitored on the days 1, 3, 7, 14 and 21. A statistically significant difference was observed throughout descriptive statistics and paired Student's t-test.CONCLUSION:Physiological healing processes of the acute burn wound following the topical application of herbal preparation can be monitored on the utilized animal model. A three-week treatment resulted in the 90% of completed epithelization in both animal species, indicating the effectiveness of topically applied herbal preparation.

  3. Short note: the experimental geopotential model XGM2016

    Science.gov (United States)

    Pail, R.; Fecher, T.; Barnes, D.; Factor, J. F.; Holmes, S. A.; Gruber, T.; Zingerle, P.

    2018-04-01

    As a precursor study for the upcoming combined Earth Gravitational Model 2020 (EGM2020), the Experimental Gravity Field Model XGM2016, parameterized as a spherical harmonic series up to degree and order 719, is computed. XGM2016 shares the same combination methodology as its predecessor model GOCO05c (Fecher et al. in Surv Geophys 38(3): 571-590, 2017. doi: 10.1007/s10712-016-9406-y). The main difference between these models is that XGM2016 is supported by an improved terrestrial data set of 15^' × 15^' gravity anomaly area-means provided by the United States National Geospatial-Intelligence Agency (NGA), resulting in significant upgrades compared to existing combined gravity field models, especially in continental areas such as South America, Africa, parts of Asia, and Antarctica. A combination strategy of relative regional weighting provides for improved performance in near-coastal ocean regions, including regions where the altimetric data are mostly unchanged from previous models. Comparing cumulative height anomalies, from both EGM2008 and XGM2016 at degree/order 719, yields differences of 26 cm in Africa and 40 cm in South America. These differences result from including additional information of satellite data, as well as from the improved ground data in these regions. XGM2016 also yields a smoother Mean Dynamic Topography with significantly reduced artifacts, which indicates an improved modeling of the ocean areas.

  4. Statistical approach for uncertainty quantification of experimental modal model parameters

    DEFF Research Database (Denmark)

    Luczak, M.; Peeters, B.; Kahsin, M.

    2014-01-01

    Composite materials are widely used in manufacture of aerospace and wind energy structural components. These load carrying structures are subjected to dynamic time-varying loading conditions. Robust structural dynamics identification procedure impose tight constraints on the quality of modal models...... represent different complexity levels ranging from coupon, through sub-component up to fully assembled aerospace and wind energy structural components made of composite materials. The proposed method is demonstrated on two application cases of a small and large wind turbine blade........ This paper aims at a systematic approach for uncertainty quantification of the parameters of the modal models estimated from experimentally obtained data. Statistical analysis of modal parameters is implemented to derive an assessment of the entire modal model uncertainty measure. Investigated structures...

  5. A two-Higgs-doublet model facing experimental hints

    Directory of Open Access Journals (Sweden)

    Crivellin Andreas

    2016-01-01

    Full Text Available Physics beyond the Standard Model has so far eluded our experimental probes. Nevertheless, a number of interesting anomalies have accumulated that can be taken as hints towards new physics: BaBar, Belle, and LHCb have found deviations of approximately 3:8σ in B → Dτν and B → D*τν; the anomalous magnetic moment of the muon differs by about 3σ from the theoretic prediction; the branching ratio for τ → μνν is about 2σ above the Standard Model expectation; and CMS and ATLAS found hints for a non-zero decay rate of h → μτ at 2.6σ. Here we consider these processes within a lepton-specific two-Higgs doublet model with additional non-standard Yukawa couplings and show how (and which of these excesses can be accommodated.

  6. Electrode-tissues interface: modeling and experimental validation

    International Nuclear Information System (INIS)

    Sawan, M; Laaziri, Y; Mounaim, F; Elzayat, E; Corcos, J; Elhilali, M M

    2007-01-01

    The electrode-tissues interface (ETI) is one of the key issues in implantable devices such as stimulators and sensors. Once the stimulator is implanted, safety and reliability become more and more critical. In this case, modeling and monitoring of the ETI are required. We propose an empirical model for the ETI and a dedicated integrated circuit to measure its corresponding complex impedance. These measurements in the frequency range of 1 Hz to 100 kHz were achieved in acute dog experiments. The model demonstrates a closer fitting with experimental measurements. In addition, a custom monitoring device based on a stimuli current generator has been completed to evaluate the phase shift and voltage across the electrodes and to transmit wirelessly the values to an external controller. This integrated circuit has been fabricated in a CMOS 0.18 μm process, which consumes 4 mW only during measurements and occupies an area of 1 mm 2 . (review article)

  7. Comparison of mixed layer models predictions with experimental data

    Energy Technology Data Exchange (ETDEWEB)

    Faggian, P.; Riva, G.M. [CISE Spa, Divisione Ambiente, Segrate (Italy); Brusasca, G. [ENEL Spa, CRAM, Milano (Italy)

    1997-10-01

    The temporal evolution of the PBL vertical structure for a North Italian rural site, situated within relatively large agricultural fields and almost flat terrain, has been investigated during the period 22-28 June 1993 by experimental and modellistic point of view. In particular, the results about a sunny day (June 22) and a cloudy day (June 25) are presented in this paper. Three schemes to estimate mixing layer depth have been compared, i.e. Holzworth (1967), Carson (1973) and Gryning-Batchvarova models (1990), which use standard meteorological observations. To estimate their degree of accuracy, model outputs were analyzed considering radio-sounding meteorological profiles and stability atmospheric classification criteria. Besides, the mixed layer depths prediction were compared with the estimated values obtained by a simple box model, whose input requires hourly measures of air concentrations and ground flux of {sup 222}Rn. (LN)

  8. MATHEMATICAL MODELLING OF PREFERED SOLUTIONS CHOICE FUNCTION FOR TUBULAR GAS HEATERS BY EXPERIMENTAL INFORMATIONS

    Directory of Open Access Journals (Sweden)

    BARSUK R. V.

    2016-08-01

    Full Text Available Annotation. Problems formulation. The article deals with choice functions building of preferred solutions by experimental information for tubular gas heater working on fuel granules - pellets.Further choice functions using for making technical solutions by tubular gas heaters construction and designing. Recently research analysis. There are works about choice functions construction by separate presents are examined. But full chose functions building by separate presents are not examined. Aims and tasks. There are setting aim to develop full choice functions mathematical model on separate presents by authors. The expert are connect to primary experimental data’s evaluation that estimates separate results by output functions (criteria. Its evaluations issue in experimental points paired comparison’s table form. Thus, there are necessary construct binary choice relations presents on experimental “points” set by expert that then using for full choice function’s constructing. Conclusions. There are choice function’s construction’s sequence are sets. There are posed point comparison results that characterized tubular gas heater’s condition with expert’s evaluation using. Also posed output functions comparisons by which can be characterized improving tubular gas heater’s performance or vice versa.

  9. Characterizing a Rat Brca2 Knockout Model

    Science.gov (United States)

    2007-05-01

    Brca2 was tested in various tumor inducing experimental settings [49,52] * activated form Hs = Homo sapiens ; Rn = Rattus norvegicus; MMTV...sequencing gDNA from a wild-type 2 SD rat over a region of intron 21 that contains the splicing branch site 2 (underlined). ( el The same sequence from the...from the El pups at 1 week of age for macromolecule isolation. We also visually checked all Fk pups for gross abnormalities in physi- cal

  10. Experimentally driven atomistic model of 1,2 polybutadiene

    Energy Technology Data Exchange (ETDEWEB)

    Gkourmpis, Thomas, E-mail: thomas.gkourmpis@borealisgroup.com [Polymer Science Centre, J. J. Thomson Physical Laboratory, Department of Physics, University of Reading, Reading RG6 6AF (United Kingdom); Mitchell, Geoffrey R. [Polymer Science Centre, J. J. Thomson Physical Laboratory, Department of Physics, University of Reading, Reading RG6 6AF (United Kingdom); Centre for Rapid and Sustainable Product Development, Institute Polytechnic Leiria, Marinha Grande (Portugal)

    2014-02-07

    We present an efficient method of combining wide angle neutron scattering data with detailed atomistic models, allowing us to perform a quantitative and qualitative mapping of the organisation of the chain conformation in both glass and liquid phases. The structural refinement method presented in this work is based on the exploitation of the intrachain features of the diffraction pattern and its intimate linkage with atomistic models by the use of internal coordinates for bond lengths, valence angles, and torsion rotations. Atomic connectivity is defined through these coordinates that are in turn assigned by pre-defined probability distributions, thus allowing for the models in question to be built stochastically. Incremental variation of these coordinates allows for the construction of models that minimise the differences between the observed and calculated structure factors. We present a series of neutron scattering data of 1,2 polybutadiene at the region 120–400 K. Analysis of the experimental data yields bond lengths for Cî—¸C and C î—» C of 1.54 Å and 1.35 Å, respectively. Valence angles of the backbone were found to be at 112° and the torsion distributions are characterised by five rotational states, a three-fold trans-skew± for the backbone and gauche± for the vinyl group. Rotational states of the vinyl group were found to be equally populated, indicating a largely atactic chan. The two backbone torsion angles exhibit different behaviour with respect to temperature of their trans population, with one of them adopting an almost all trans sequence. Consequently, the resulting configuration leads to a rather persistent chain, something indicated by the value of the characteristic ratio extrapolated from the model. We compare our results with theoretical predictions, computer simulations, RIS models and previously reported experimental results.

  11. Experimental and numerical modeling of sulfur plugging in carbonate reservoirs

    Energy Technology Data Exchange (ETDEWEB)

    Abou-Kassem, J.H. [Chemical and Petroleum Engineering Department, UAE University, PO Box 17555, Al-Ain (United Arab Emirates)

    2000-05-01

    Sour gas, mainly in the form of hydrogen sulfide, is produced in large amounts from many oil and gas reservoirs in the United Arab Emirates. In addition to creating problems in production lines, the precipitation of elemental sulfur in vicinity of the wellbore is often reported to cause wellbore damage. While there have been several studies performed on the role of solid deposition in gas reservoirs, the role of sulfur deposition in oil reservoirs has not been investigated. This paper presents experimental results along with a comprehensive wellbore model that predicts sulfur precipitation as well as plugging. Two separate sets of experiments, one for a gas phase system and another for a crude oil system, were conducted to investigate the deposition of elemental sulfur in (linear) carbonate cores. The gas flow tests were conducted with elemental sulfur being carried with nitrogen through limestone cores. Changes in gas flow rate were monitored while the injection pressure was held constant. A series of experiments generated valuable data for plugging with elemental sulfur. X-ray diffraction tests provided evidence of sulfur deposition along the cores. The oil flow tests were carried out to observe sulfur precipitation and plugging in a carbonate core. The crude oil was de-asphalted before conducting these tests in order to isolate the effect of asphaltene plugging. Significant plugging was observed and was found to be dependent on flow rate and initial sulfur concentration. This information was used in a phenomenological model that was incorporated in the wellbore numerical model. The data for the numerical model were obtained from both test tube and oil flow experiments. By using a phenomenological model, the wellbore plugging was modeled with an excellent match (with experimental results)

  12. A model based bayesian solution for characterization of complex damage scenarios in aerospace composite structures.

    Science.gov (United States)

    Reed, H; Leckey, Cara A C; Dick, A; Harvey, G; Dobson, J

    2018-01-01

    Ultrasonic damage detection and characterization is commonly used in nondestructive evaluation (NDE) of aerospace composite components. In recent years there has been an increased development of guided wave based methods. In real materials and structures, these dispersive waves result in complicated behavior in the presence of complex damage scenarios. Model-based characterization methods utilize accurate three dimensional finite element models (FEMs) of guided wave interaction with realistic damage scenarios to aid in defect identification and classification. This work describes an inverse solution for realistic composite damage characterization by comparing the wavenumber-frequency spectra of experimental and simulated ultrasonic inspections. The composite laminate material properties are first verified through a Bayesian solution (Markov chain Monte Carlo), enabling uncertainty quantification surrounding the characterization. A study is undertaken to assess the efficacy of the proposed damage model and comparative metrics between the experimental and simulated output. The FEM is then parameterized with a damage model capable of describing the typical complex damage created by impact events in composites. The damage is characterized through a transdimensional Markov chain Monte Carlo solution, enabling a flexible damage model capable of adapting to the complex damage geometry investigated here. The posterior probability distributions of the individual delamination petals as well as the overall envelope of the damage site are determined. Copyright © 2017 Elsevier B.V. All rights reserved.

  13. Neuroinflammatory targets and treatments for epilepsy validated in experimental models.

    Science.gov (United States)

    Aronica, Eleonora; Bauer, Sebastian; Bozzi, Yuri; Caleo, Matteo; Dingledine, Raymond; Gorter, Jan A; Henshall, David C; Kaufer, Daniela; Koh, Sookyong; Löscher, Wolfgang; Louboutin, Jean-Pierre; Mishto, Michele; Norwood, Braxton A; Palma, Eleonora; Poulter, Michael O; Terrone, Gaetano; Vezzani, Annamaria; Kaminski, Rafal M

    2017-07-01

    A large body of evidence that has accumulated over the past decade strongly supports the role of inflammation in the pathophysiology of human epilepsy. Specific inflammatory molecules and pathways have been identified that influence various pathologic outcomes in different experimental models of epilepsy. Most importantly, the same inflammatory pathways have also been found in surgically resected brain tissue from patients with treatment-resistant epilepsy. New antiseizure therapies may be derived from these novel potential targets. An essential and crucial question is whether targeting these molecules and pathways may result in anti-ictogenesis, antiepileptogenesis, and/or disease-modification effects. Therefore, preclinical testing in models mimicking relevant aspects of epileptogenesis is needed to guide integrated experimental and clinical trial designs. We discuss the most recent preclinical proof-of-concept studies validating a number of therapeutic approaches against inflammatory mechanisms in animal models that could represent novel avenues for drug development in epilepsy. Finally, we suggest future directions to accelerate preclinical to clinical translation of these recent discoveries. Wiley Periodicals, Inc. © 2017 International League Against Epilepsy.

  14. Tyre tread-block friction: modelling, simulation and experimental validation

    Science.gov (United States)

    Wallaschek, Jörg; Wies, Burkard

    2013-07-01

    Pneumatic tyres are used in vehicles since the beginning of the last century. They generate braking and steering forces for bicycles, motor cycles, cars, busses, trucks, agricultural vehicles and aircraft. These forces are generated in the usually very small contact area between tyre and road and their performance characteristics are of eminent importance for safety and comfort. Much research has been addressed to optimise tyre design with respect to footprint pressure and friction. In this context, the development of virtual tyre prototypes, that is, simulation models for the tyre, has grown to a science in its own. While the modelling of the structural dynamics of the tyre has reached a very advanced level, which allows to take into account effects like the rate-independent inelasticity of filled elastomers or the transient 3D deformations of the ply-reinforced tread, shoulder and sidewalls, little is known about the friction between tread-block elements and road. This is particularly obvious in the case when snow, ice, water or a third-body layer are present in the tyre-road contact. In the present paper, we give a survey on the present state of knowledge in the modelling, simulation and experimental validation of tyre tread-block friction processes. We concentrate on experimental techniques.

  15. Hepatoprotective activity of Musa paradisiaca on experimental animal models.

    Science.gov (United States)

    Nirmala, M; Girija, K; Lakshman, K; Divya, T

    2012-01-01

    To investigate the hepatoprotective activity of stem of Musa paradisiaca (M. paradisiaca) in CCl4 and paracetamol induced hepatotoxicity models in rats. Hepatoprotective activity of alcoholic and aqueous extracts of stem of M. paradisiaca was demonstrated by using two experimentally induced hepatotoxicity models. Administration of hepatotoxins (CCl4 and paracetamol) showed significant biochemical and histological deteriorations in the liver of experimental animals. Pretreatment with alcoholic extract (500 mg/kg), more significantly and to a lesser extent the alcoholic extract (250 mg/kg) and aqueous extract (500 mg/kg), reduced the elevated levels of the serum enzymes like serum glutamic-oxaloacetic transaminase (SGOT), serum glutamic pyruvic transaminase (SGPT), alkaline phosphatase (ALP) and bilirubin levels and alcoholic and aqueous extracts reversed the hepatic damage towards the normal, which further evidenced the hepatoprotective activity of stem of M. paradisiaca. The alcoholic extract at doses of 250 and 500 mg/kg, p.o. and aqueous extract at a dose of 500 mg/kg, p.o. of stem of M. paradisiaca have significant effect on the liver of CCl4 and paracetamol induced hepatotoxicity animal models.

  16. A comprehensive experimental and modeling study of 2-methylbutanol combustion

    KAUST Repository

    Park, Sungwoo

    2015-05-01

    2-Methylbutanol (2-methyl-1-butanol) is one of several next-generation biofuels that can be used as an alternative fuel or blending component for combustion engines. This paper presents new experimental data for 2-methylbutanol, including ignition delay times in a high-pressure shock tube and premixed laminar flame speeds in a constant volume combustion vessel. Shock tube ignition delay times were measured for 2-methylbutanol/air mixtures at three equivalence ratios, temperatures ranging from 750 to 1250. K, and at nominal pressures near 20 and 40. bar. Laminar flame speed data were obtained using the spherically propagating premixed flame configuration at pressures of 1, 2, and 5. bar. A detailed chemical kinetic model for 2-methylbutanol oxidation was developed including high- and low-temperature chemistry based on previous modeling studies on butanol and pentanol isomers. The proposed model was tested against new and existing experimental data at pressures of 1-40. atm, temperatures of 740-1636. K, equivalence ratios of 0.25-2.0. Reaction path and sensitivity analyses were conducted for identifying key reactions at various combustion conditions, and to obtain better understanding of the combustion characteristics of larger alcohols.

  17. Experimental models of sepsis and septic shock: an overview

    Directory of Open Access Journals (Sweden)

    Garrido Alejandra G.

    2004-01-01

    Full Text Available Sepsis remains a major cause of morbidity and mortality in surgical patients and trauma victims, mainly due to sepsis-induced multiple organ dysfunction. In contrast to preclinical studies, most clinical trials of promising new treatment strategies for sepsis have fails to demonstrate efficacy. Although many reasons could account for this discrepancy, the misinterpretation of preclinical data obtained from experimental studies, and especially the use of animal models that do not adequately mimic human sepsis may have been contributing factors. In this review, the benefits and limitations of various animal models of sepsis are discussed to clarify the extend to which findings are relevant to human sepsis, particularly with respect to the subsequent design and execution of clinical trials. Such models include intravascular infusion of endotoxin or live bacteria, bacterial peritonitis, cecal ligation and perforation, soft tissue infection, pneumonia or meningitis models, using different animal species including rats, mice, rabbits, dogs, pigs, sheep and nonhuman primates. Despite several limitations, animal models remain essential in the development of all new therapies for sepsis and septic shock, because they provide fundamental information about the pharmacokinetics, toxicity, and mechanism of drug action that cannot be duplicated by other methods. New therapeutic agents should be studies in infection models, even after the initiation of the septic process. Furthermore, debility conditions need to be reproduced to avoid the exclusive use of healthy animals, which often do not represent the human septic patient.

  18. Experimental measurements and modelling of the WEGA boundary layer plasma

    International Nuclear Information System (INIS)

    El Shaer, M.; Ichtchenko, G.

    1983-02-01

    The boundary layer of the WEGA Tokamak has been investigated by using specific diagnostics: movable 4 mm microwave interferometer, several types of movable and fixed probes, Katsumata probe, and multigrid electrostatic analyzer. During the RF heating at the lower hybrid frequency, some modifications in the parameters of the boundary layer are observed which are interpreted by the ponderomotive force effects. A comparison between the measured reflection coefficients of the grill waveguides and their predicted values by a coupling theory (not taking into account the real conditions facing the Grill) is presented. A diffusion model was also made to describe this particular region and to fit the experimental results

  19. Establishment of selected acute pulmonary thromboembolism model in experimental sheep

    International Nuclear Information System (INIS)

    Fan Jihai; Gu Xiulian; Chao Shengwu; Zhang Peng; Fan Ruilin; Wang Li'na; Wang Lulu; Wang Ling; Li Bo; Chen Taotao

    2010-01-01

    Objective: To establish a selected acute pulmonary thromboembolism model in experimental sheep suitable for animal experiment. Methods: By using Seldinger's technique the catheter sheath was placed in both the femoral vein and femoral artery in ten sheep. Under C-arm DSA guidance the catheter was inserted through the catheter sheath into the pulmonary artery. Via the catheter appropriate amount of sheep autologous blood clots was injected into the selected pulmonary arteries. The selected acute pulmonary thromboembolism model was thus established. Pulmonary angiography was performed to check the results. The pulmonary arterial pressure, femoral artery pressure,heart rates and partial pressure of oxygen in arterial blood (PaO 2 ) were determined both before and after the treatment. The above parameters obtained after the procedure were compared with the recorded parameters measured before the procedure, and the sheep model quality was evaluated. Results: The baseline of pulmonary arterial pressure was (27.30 ± 9.58) mmHg,femoral artery pressure was (126.4 ± 13.72) mmHg, heart rate was (103 ± 15) bpm and PaO 2 was (87.7 ± 12.04) mmHg. Sixty minutes after the injection of (30 ± 5) ml thrombotic agglomerates, the pulmonary arterial pressures rose to (52 ± 49) mmHg, femoral artery pressures dropped to (100 ± 21) mmHg. The heart rates went up to (150 ± 26) bpm. The PaO 2 fell to (25.3 ± 11.2) mmHg. After the procedure the above parameters were significantly different from that measured before the procedure in all ten animals (P < 0.01). The pulmonary arteriography clearly demonstrated that the selected pulmonary arteries were successfully embolized. Conclusion: The anatomy of sheep's femoral veins,vena cava system, pulmonary artery and right heart system are suitable for the establishment of the catheter passage, for this reason, selected acute pulmonary thromboembolism model can be easily created in experimental sheep. The technique is feasible and the model

  20. CFD Modeling and Experimental Validation of a Solar Still

    Directory of Open Access Journals (Sweden)

    Mahmood Tahir

    2017-01-01

    Full Text Available Earth is the densest planet of the solar system with total area of 510.072 million square Km. Over 71.68% of this area is covered with water leaving a scant area of 28.32% for human to inhabit. The fresh water accounts for only 2.5% of the total volume and the rest is the brackish water. Presently, the world is facing chief problem of lack of potable water. This issue can be addressed by converting brackish water into potable through a solar distillation process and solar still is specially assigned for this purpose. Efficiency of a solar still explicitly depends on its design parameters, such as wall material, chamber depth, width and slope of the zcondensing surface. This study was aimed at investigating the solar still parameters using CFD modeling and experimental validation. The simulation data of ANSYS-FLUENT was compared with actual experimental data. A close agreement among the simulated and experimental results was seen in the presented work. It reveals that ANSYS-FLUENT is a potent tool to analyse the efficiency of the new designs of the solar distillation systems.

  1. Computational and experimental model of transdermal iontophorethic drug delivery system.

    Science.gov (United States)

    Filipovic, Nenad; Saveljic, Igor; Rac, Vladislav; Graells, Beatriz Olalde; Bijelic, Goran

    2017-11-30

    The concept of iontophoresis is often applied to increase the transdermal transport of drugs and other bioactive agents into the skin or other tissues. It is a non-invasive drug delivery method which involves electromigration and electroosmosis in addition to diffusion and is shown to be a viable alternative to conventional administration routs such as oral, hypodermic and intravenous injection. In this study we investigated, experimentally and numerically, in vitro drug delivery of dexamethasone sodium phosphate to porcine skin. Different current densities, delivery durations and drug loads were investigated experimentally and introduced as boundary conditions for numerical simulations. Nernst-Planck equation was used for calculation of active substance flux through equivalent model of homogeneous hydrogel and skin layers. The obtained numerical results were in good agreement with experimental observations. A comprehensive in-silico platform, which includes appropriate numerical tools for fitting, could contribute to iontophoretic drug-delivery devices design and correct dosage and drug clearance profiles as well as to perform much faster in-silico experiments to better determine parameters and performance criteria of iontophoretic drug delivery. Copyright © 2017 Elsevier B.V. All rights reserved.

  2. Experimental validation of a method characterizing bow tie filters in CT scanners using a real-time dose probe

    International Nuclear Information System (INIS)

    McKenney, Sarah E.; Nosratieh, Anita; Gelskey, Dale; Yang Kai; Huang Shinying; Chen Lin; Boone, John M.

    2011-01-01

    Purpose: Beam-shaping or ''bow tie'' (BT) filters are used to spatially modulate the x-ray beam in a CT scanner, but the conventional method of step-and-shoot measurement to characterize a beam's profile is tedious and time-consuming. The theory for characterization of bow tie relative attenuation (COBRA) method, which relies on a real-time dosimeter to address the issues of conventional measurement techniques, was previously demonstrated using computer simulations. In this study, the feasibility of the COBRA theory is further validated experimentally through the employment of a prototype real-time radiation meter and a known BT filter. Methods: The COBRA method consisted of four basic steps: (1) The probe was placed at the edge of a scanner's field of view; (2) a real-time signal train was collected as the scanner's gantry rotated with the x-ray beam on; (3) the signal train, without a BT filter, was modeled using peak values measured in the signal train of step 2; and (4) the relative attenuation of the BT filter was estimated from filtered and unfiltered data sets. The prototype probe was first verified to have an isotropic and linear response to incident x-rays. The COBRA method was then tested on a dedicated breast CT scanner with a custom-designed BT filter and compared to the conventional step-and-shoot characterization of the BT filter. Using basis decomposition of dual energy signal data, the thickness of the filter was estimated and compared to the BT filter's manufacturing specifications. The COBRA method was also demonstrated with a clinical whole body CT scanner using the body BT filter. The relative attenuation was calculated at four discrete x-ray tube potentials and used to estimate the thickness of the BT filter. Results: The prototype probe was found to have a linear and isotropic response to x-rays. The relative attenuation produced from the COBRA method fell within the error of the relative attenuation measured with the step-and-shoot method

  3. Characterization and Modeling of Network Traffic

    DEFF Research Database (Denmark)

    Shawky, Ahmed; Bergheim, Hans; Ragnarsson, Olafur

    2011-01-01

    -arrival time, IP addresses, port numbers and transport protocol are the only necessary parameters to model network traffic behaviour. In order to recreate this behaviour, a complex model is needed which is able to recreate traffic behaviour based on a set of statistics calculated from the parameters values...

  4. Experimental validation of a kilovoltage x-ray source model for computing imaging dose

    Energy Technology Data Exchange (ETDEWEB)

    Poirier, Yannick, E-mail: yannick.poirier@cancercare.mb.ca [CancerCare Manitoba, 675 McDermot Ave, Winnipeg, Manitoba R3E 0V9 (Canada); Kouznetsov, Alexei; Koger, Brandon [Department of Physics and Astronomy, University of Calgary, Calgary, Alberta T2N 1N4 (Canada); Tambasco, Mauro, E-mail: mtambasco@mail.sdsu.edu [Department of Physics, San Diego State University, San Diego, California 92182-1233 and Department of Physics and Astronomy and Department of Oncology, University of Calgary, Calgary, Alberta T2N 1N4 (Canada)

    2014-04-15

    computed counterparts resulting in an agreement within 2.5%, 5%, and 8% within solid water, bone, and lung, respectively. Conclusions: The proposed virtual point source model and characterization method can be used to compute absorbed dose in both the homogeneous and heterogeneous block phantoms within of 2%–8% of measured values, depending on the phantom and the beam quality. The authors’ results also provide experimental validation for their kV dose computation software, kVDoseCalc.

  5. Electrical characterization and an equivalent circuit model of a microhollow cathode discharge reactor

    International Nuclear Information System (INIS)

    Taylan, O.; Berberoglu, H.

    2014-01-01

    This paper reports the electrical characterization and an equivalent circuit of a microhollow cathode discharge (MHCD) reactor in the self-pulsing regime. A MHCD reactor was prototyped for air plasma generation, and its current-voltage characteristics were measured experimentally in the self-pulsing regime for applied voltages from 2000 to 3000 V. The reactor was modeled as a capacitor in parallel with a variable resistor. A stray capacitance was also introduced to the circuit model to represent the capacitance of the circuit elements in the experimental setup. The values of the resistor and capacitors were recovered from experimental data, and the proposed circuit model was validated with independent experiments. Experimental data showed that increasing the applied voltage increased the current, self-pulsing frequency and average power consumption of the reactor, while it decreased the peak voltage. The maximum and the minimum voltages obtained using the model were in agreement with the experimental data within 2.5%, whereas the differences between peak current values were less than 1%. At all applied voltages, the equivalent circuit model was able to accurately represent the peak and average power consumption as well as the self-pulsing frequency within the experimental uncertainty. Although the results shown in this paper was for atmospheric air pressures, the proposed equivalent circuit model of the MHCD reactor could be generalized for other gases at different pressures.

  6. An efficient approach to bioconversion kinetic model generation based on automated microscale experimentation integrated with model driven experimental design

    DEFF Research Database (Denmark)

    Chen, B. H.; Micheletti, M.; Baganz, F.

    2009-01-01

    -erythrulose. Experiments were performed using automated microwell studies at the 150 or 800 mu L scale. The derived kinetic parameters were then verified in a second round of experiments where model predictions showed excellent agreement with experimental data obtained under conditions not included in the original......Reliable models of enzyme kinetics are required for the effective design of bioconversion processes. Kinetic expressions of the enzyme-catalysed reaction rate however, are frequently complex and establishing accurate values of kinetic parameters normally requires a large number of experiments....... These can be both time consuming and expensive when working with the types of non-natural chiral intermediates important in pharmaceutical syntheses. This paper presents ail automated microscale approach to the rapid and cost effective generation of reliable kinetic models useful for bioconversion process...

  7. Experimental characterization of a new multicasting node architecture based on space splitters and wavelength converters

    Science.gov (United States)

    He, Hao; Su, Yikai; Hu, Peigang; Hu, Weisheng

    2005-11-01

    IPTV-based broadband services such as interactive multimedia and video conferencing are considered as promising revenue-adding services, and multicast is proven to be a good supplier to support these applications for its reduced consumption of network bandwidth. Generally there are two approaches to implement optical layer multicast. One is space-domain multicast using space-splitter which is low cost but has wavelength continuity constraint, the other is frequency-domain multicast using wavelength converter which resolves the wavelength continuity but with high costs. A new multicasting node which adopts both space-domain multicast and frequency-domain multicast is recently discussed. In this paper we present an experimental demonstration of the new multicasting node architecture based on space splitters and wavelength converters, measurements to characterize such a node are provided.

  8. Quality Assurance Program Plan for the Waste Isolation Pilot Plant Experimental-Waste Characterization Program

    International Nuclear Information System (INIS)

    1991-01-01

    This Quality Assurance Program Plan (QAPP) identifies the quality of data necessary to meet the specific objectives associated with the Department of Energy (DOE) Waste Isolation Pilot Plant (WIPP) Experimental-Waste Characterization Program (the Program). DOE plans to conduct experiments in the WIPP during a Test Phase of approximately 5 years. These experiments will be conducted to reduce the uncertainties associated with the prediction of several processes (e.g., gas generation) that may influence repository performance. The results of the experiments will be used to assess the ability of the WIPP to meet regulatory requirements for the long-term protection of human health and the environment from the disposal of TRU wastes. 37 refs., 25 figs., 18 tabs

  9. Evanescently Coupled Rectangular Microresonators in Silicon-on-Insulator with High Q-Values: Experimental Characterization

    Directory of Open Access Journals (Sweden)

    Manuel Mendez-Astudillo

    2017-04-01

    Full Text Available We report on evanescently coupled rectangular microresonators with dimensions up to 20 × 10 μm2 in silicon-on-insulator in an add-drop filter configuration. The influence of the geometrical parameters of the device was experimentally characterized and a high Q value of 13,000 was demonstrated as well as the multimode optical resonance characteristics in the drop port. We also show a 95% energy transfer between ports when the device is operated in TM-polarization and determine the full symmetry of the device by using an eight-port configuration, allowing the drop waveguide to be placed on any of its sides, providing a way to filter and route optical signals. We used the FDTD method to analyze the device and e-beam lithography and dry etching techniques for fabrication.

  10. A wideband fractal-inspired piezoelectric energy converter: design, simulation and experimental characterization

    International Nuclear Information System (INIS)

    Castagnetti, Davide

    2013-01-01

    In order to develop self-powered wireless sensor nodes, many energy harvesting devices that are able to convert available ambient energy into electrical energy have been proposed in the literature. A promising technique, in terms of simplicity and high conversion efficiency, is the harvesting of ambient kinetic energy through piezoelectric materials. The aim of this work is to design and investigate the modal response and power output of a fractal-inspired, multi-frequency, piezoelectric energy converter. The converter is a square, thin sheet structure, characterized by a fractal geometry obtained through a pattern of cuts in the plate. There are two steps involved. First, a computational analysis of the converter is performed. Second, a physical prototype of the converter is built and its eigenfrequencies and power generation under different resistive loads are experimentally examined in the range from 0 to 120 Hz. The converter exhibits three eigenfrequencies and a good power output, particularly at the first eigenfrequency. (paper)

  11. Assessing Model Characterization of Single Source ...

    Science.gov (United States)

    Aircraft measurements made downwind from specific coal fired power plants during the 2013 Southeast Nexus field campaign provide a unique opportunity to evaluate single source photochemical model predictions of both O3 and secondary PM2.5 species. The model did well at predicting downwind plume placement. The model shows similar patterns of an increasing fraction of PM2.5 sulfate ion to the sum of SO2 and PM2.5 sulfate ion by distance from the source compared with ambient based estimates. The model was less consistent in capturing downwind ambient based trends in conversion of NOX to NOY from these sources. Source sensitivity approaches capture near-source O3 titration by fresh NO emissions, in particular subgrid plume treatment. However, capturing this near-source chemical feature did not translate into better downwind peak estimates of single source O3 impacts. The model estimated O3 production from these sources but often was lower than ambient based source production. The downwind transect ambient measurements, in particular secondary PM2.5 and O3, have some level of contribution from other sources which makes direct comparison with model source contribution challenging. Model source attribution results suggest contribution to secondary pollutants from multiple sources even where primary pollutants indicate the presence of a single source. The National Exposure Research Laboratory (NERL) Computational Exposure Division (CED) develops and evaluates data, deci

  12. Experimental validation of models for Plasma Focus devices

    International Nuclear Information System (INIS)

    Rodriguez Palomino, Luis; Gonzalez, Jose; Clausse, Alejandro

    2003-01-01

    Plasma Focus(PF) Devices are thermonuclear pulsators that produce short pulsed radiation (X-ray, charged particles and neutrons). Since Filippov and Mather, investigations have been used to study plasma properties. Nowadays the interest about PF is focused in technology applications, related to the use of these devices as pulsed neutron sources. In the numerical calculus the Inter institutional PLADEMA (PLAsmas DEnsos MAgnetizados) network is developing three models. Each one is useful in different engineering stages of the Plasma Focus design. One of the main objectives in this work is a comparative study on the influence of the different parameters involved in each models. To validate these results, several experimental measurements under different geometry and initial conditions were performed. (author)

  13. Astrocyte regulation of sleep circuits: experimental and modeling perspectives

    Directory of Open Access Journals (Sweden)

    Tommaso eFellin

    2012-08-01

    Full Text Available Integrated within neural circuits, astrocytes have recently been shown to modulate brain rhythms thought to mediate sleep function. Experimental evidence suggests that local impact of astrocytes on single synapses translates into global modulation of neuronal networks and behavior. We discuss these findings in the context of current conceptual models of sleep generation and function, each of which have historically focused on neural mechanisms. We highlight the implications and the challenges introduced by these results from a conceptual and computational perspective. We further provide modeling directions on how these data might extend our knowledge of astrocytic properties and sleep function. Given our evolving understanding of how local cellular activities during sleep lead to functional outcomes for the brain, further mechanistic and theoretical understanding of astrocytic contribution to these dynamics will undoubtedly be of great basic and translational benefit.

  14. An experimental and modeling study of n-octanol combustion

    KAUST Repository

    Cai, Liming

    2015-01-01

    This study presents the first investigation on the combustion chemistry of n-octanol, a long chain alcohol. Ignition delay times were determined experimentally in a high-pressure shock tube, and stable species concentration profiles were obtained in a jet stirred reactor for a range of initial conditions. A detailed kinetic model was developed to describe the oxidation of n-octanol at both low and high temperatures, and the model shows good agreement with the present dataset. The fuel\\'s combustion characteristics are compared to those of n-alkanes and to short chain alcohols to illustrate the effects of the hydroxyl moiety and the carbon chain length on important combustion properties. Finally, the results are discussed in detail. © 2014 The Combustion Institute.

  15. Experimentally supported mathematical modeling of continuous baking processes

    DEFF Research Database (Denmark)

    Stenby Andresen, Mette

    and temperature) and control the process (air flow, temperature, and humidity) are therefore emphasized. The oven is furthermore designed to work outside the range of standard tunnel ovens, making it interesting for manufacturers of both baking products and baking equipment. A mathematical model describing......The scope of the PhD project was to increase knowledge on the process-to-product interactions in continuous tunnel ovens. The work has focused on five main objectives. These objectives cover development of new experimental equipment for pilot plant baking experiments, mathematical modeling of heat...... and mass transfer in a butter cookie product, and evaluation of quality assessment methods. The pilot plant oven is a special batch oven designed to emulate continuous convection tunnel oven baking. The design, construction, and validation of the oven has been part of the project and is described...

  16. Simulator for candu600 fuel handling system. the experimental model

    International Nuclear Information System (INIS)

    Marinescu, N.; Predescu, D.; Valeca, S.

    2013-01-01

    A main way to increase the nuclear plant safety is related to selection and continuous training of the operation staff. In this order, the computer programs for training, testing and evaluation of the knowledge get, or training simulators including the advanced analytical models of the technological systems are using. The Institute for Nuclear Research from Pitesti, Romania intend to design and build an Fuel Handling Simulator at his F/M Head Test Rig facility, that will be used for training of operating personnel. This paper presents simulated system, advantages to use the simulator, and the experimental model of simulator, that has been built to allows setting of the requirements and fabrication details, especially for the software kit that will be designed and implement on main simulator. (authors)

  17. Antioxidant Capacity: Experimental Determination by EPR Spectroscopy and Mathematical Modeling.

    Science.gov (United States)

    Polak, Justyna; Bartoszek, Mariola; Chorążewski, Mirosław

    2015-07-22

    A new method of determining antioxidant capacity based on a mathematical model is presented in this paper. The model was fitted to 1000 data points of electron paramagnetic resonance (EPR) spectroscopy measurements of various food product samples such as tea, wine, juice, and herbs with Trolox equivalent antioxidant capacity (TEAC) values from 20 to 2000 μmol TE/100 mL. The proposed mathematical equation allows for a determination of TEAC of food products based on a single EPR spectroscopy measurement. The model was tested on the basis of 80 EPR spectroscopy measurements of herbs, tea, coffee, and juice samples. The proposed model works for both strong and weak antioxidants (TEAC values from 21 to 2347 μmol TE/100 mL). The determination coefficient between TEAC values obtained experimentally and TEAC values calculated with proposed mathematical equation was found to be R(2) = 0.98. Therefore, the proposed new method of TEAC determination based on a mathematical model is a good alternative to the standard EPR method due to its being fast, accurate, inexpensive, and simple to perform.

  18. Experimental and modeling investigation on structure H hydrate formation kinetics

    International Nuclear Information System (INIS)

    Mazraeno, M. Seyfi; Varaminian, F.; Vafaie sefti, M.

    2013-01-01

    Highlights: • Applying affinity model for the formation kinetics of sH hydrate and two stage kinetics. • Performing the experiments of hydrate formation of sH with MCP. • A unique path for the SH hydrate formation. - Abstract: In this work, the kinetics of crystal H hydrate and two stage kinetics formation is modeled by using the chemical affinity model for the first time. The basic idea is that there is a unique path for each experiment by which the crystallization process decays the affinity. The experiments were performed at constant temperatures of 274.15, 275.15, 275.65, 276.15 and 277.15 K. The initial pressure of each experiment is up to 25 bar above equilibrium pressure of sI. Methylcyclohexane (MCH), methylcyclopentane (MCP) and tert-butyl methyl ether (TBME) are used as sH former and methane is used as a help gas. The parameters of the affinity model (A r and t k ) are determined and the results show that the parameter of (A r )/(RT) has not a constant value when temperature changes in each group of experiments. The results indicate that this model can predict experimental data very well at several conditions

  19. Maternal hypothyroidism: An overview of current experimental models.

    Science.gov (United States)

    Ghanbari, Mahboubeh; Ghasemi, Asghar

    2017-10-15

    Maternal hypothyroidism (MH) is the most common cause of transient congenital hypothyroidism. Different animal models are used for assessing developmental effects of MH in offspring. The severity and status of hypothyroidism in animal models must be a reflection of the actual conditions in humans. To obtain comparable results with different clinical conditions, which lead to MH in humans, several factors have been suggested for researchers to consider before designing the experimental models. Regarding development of fetal body systems during pregnancy, interference at different times provides different results and the appropriate time for induction of hypothyroidism should be selected based on accurate time of development of the system under assessment. Other factors that should be taken into consideration include, physiological and biochemical differences between humans and other species, thyroid hormone-independent effects of anti-thyroid drugs, circadian rhythms in TSH secretion, sex differences, physical and psychological stress. This review addresses essential guidelines for selecting and managing the optimal animal model for MH as well as discussing the pros and cons of currently used models. Copyright © 2017 Elsevier Inc. All rights reserved.

  20. An experimental methodology for a fuzzy set preference model

    Science.gov (United States)

    Turksen, I. B.; Willson, Ian A.

    1992-01-01

    models and vague linguistic preferences has greatly limited the usefulness and predictive validity of existing preference models. A fuzzy set preference model that uses linguistic variables and a fully interactive implementation should be able to simultaneously address these issues and substantially improve the accuracy of demand estimates. The parallel implementation of crisp and fuzzy conjoint models using identical data not only validates the fuzzy set model but also provides an opportunity to assess the impact of fuzzy set definitions and individual attribute choices implemented in the interactive methodology developed in this research. The generalized experimental tools needed for conjoint models can also be applied to many other types of intelligent systems.

  1. Experimental characterization and numerical simulation of riveted lap-shear joints using Rivet Element

    Science.gov (United States)

    Vivio, Francesco; Fanelli, Pierluigi; Ferracci, Michele

    2018-03-01

    In aeronautical and automotive industries the use of rivets for applications requiring several joining points is now very common. In spite of a very simple shape, a riveted junction has many contact surfaces and stress concentrations that make the local stiffness very difficult to be calculated. To overcome this difficulty, commonly finite element models with very dense meshes are performed for single joint analysis because the accuracy is crucial for a correct structural analysis. Anyhow, when several riveted joints are present, the simulation becomes computationally too heavy and usually significant restrictions to joint modelling are introduced, sacrificing the accuracy of local stiffness evaluation. In this paper, we tested the accuracy of a rivet finite element presented in previous works by the authors. The structural behaviour of a lap joint specimen with a rivet joining is simulated numerically and compared to experimental measurements. The Rivet Element, based on a closed-form solution of a reference theoretical model of the rivet joint, simulates local and overall stiffness of the junction combining high accuracy with low degrees of freedom contribution. In this paper the Rivet Element performances are compared to that of a FE non-linear model of the rivet, built with solid elements and dense mesh, and to experimental data. The promising results reported allow to consider the Rivet Element able to simulate, with a great accuracy, actual structures with several rivet connections.

  2. Impedance Characterization and Modeling of Lithium-Ion Batteries Considering the Internal Temperature Gradient

    Directory of Open Access Journals (Sweden)

    Haifeng Dai

    2018-01-01

    Full Text Available Battery impedance is essential to the management of lithium-ion batteries for electric vehicles (EVs, and impedance characterization can help to monitor and predict the battery states. Many studies have been undertaken to investigate impedance characterization and the factors that influence impedance. However, few studies regarding the influence of the internal temperature gradient, which is caused by heat generation during operation, have been presented. We have comprehensively studied the influence of the internal temperature gradient on impedance characterization and the modeling of battery impedance, and have proposed a discretization model to capture battery impedance characterization considering the temperature gradient. Several experiments, including experiments with artificial temperature gradients, are designed and implemented to study the influence of the internal temperature gradient on battery impedance. Based on the experimental results, the parameters of the non-linear impedance model are obtained, and the relationship between the parameters and temperature is further established. The experimental results show that the temperature gradient will influence battery impedance and the temperature distribution can be considered to be approximately linear. The verification results indicate that the proposed discretization model has a good performance and can be used to describe the actual characterization of the battery with an internal temperature gradient.

  3. Experimental model for research on the blood-ocular barrier

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hak Jin; Jea, Seung Youn; Park, Jae Sung; Jung, Yeon Joo [Pusan National University, Pusan (Korea, Republic of); Kim, Yong Woo [Inje University, Kimhae (Korea, Republic of); Park, Byung Rae [Catholic University, Seoul (Korea, Republic of)

    2006-03-15

    The eyeball has 2 blood-ocular barriers, i.e, the blood-retinal and blood-aqueous barriers. The purpose of this study was to evaluate if triolein emulsion could disrupt the barriers, and we wanted to suggest as an experimental model for future blood-ocular barrier studies. The triolein emulsion was made of 0.1 ml triolein and 20 ml normal saline, and this was infused into the carotid artery of ten cats (the experimental group). As a control group, only normal saline was infused in another ten cats. Precontrast and postcontrast T1-weighted MR images were obtained at 30 minutes and 3 hours after embolization in both groups. The signal intensities were evaluate qualitatively and quantitatively in the anterior and posterior chambers and also in the vitreus fluid. Statistical analysis was performed by employing the Kruskal Wallist test, Dunn's Multiple Comparison test and the wilcoxon signed rank test. In the control group, no contrast enhancement was demonstrated in the anterior or posterior chamber or in the vitreus fluid of the ipsilateral or contralateral eyeball on the 30 minutes MR images. The anterior chambers of the ipsilateral and contralateral eyeballs revealed delayed contrast enhancement on the 3 hour MR images. In the experimental group, the 30 minute-postembolization MR images were not different from those of the control group. The 30 minute-postembolization MR images demonstrated delayed contrast enhancement in the anterior chamber of the ipsilateral and contralateral eyeballs and in the posterior chamber of the ipsilateral eyeball. The delayed contrast enhancement of the posterior chamber of the ipsilateral eyeball was statistically significant ({rho} < 0.05). The present study demonstrated significant contrast enhancement in the posterior chamber with infusion of the triolein emulsion, and this can serve as a model for blood-aqueous barrier studies.

  4. Experimental model for research on the blood-ocular barrier

    International Nuclear Information System (INIS)

    Kim, Hak Jin; Jea, Seung Youn; Park, Jae Sung; Jung, Yeon Joo; Kim, Yong Woo; Park, Byung Rae

    2006-01-01

    The eyeball has 2 blood-ocular barriers, i.e, the blood-retinal and blood-aqueous barriers. The purpose of this study was to evaluate if triolein emulsion could disrupt the barriers, and we wanted to suggest as an experimental model for future blood-ocular barrier studies. The triolein emulsion was made of 0.1 ml triolein and 20 ml normal saline, and this was infused into the carotid artery of ten cats (the experimental group). As a control group, only normal saline was infused in another ten cats. Precontrast and postcontrast T1-weighted MR images were obtained at 30 minutes and 3 hours after embolization in both groups. The signal intensities were evaluate qualitatively and quantitatively in the anterior and posterior chambers and also in the vitreus fluid. Statistical analysis was performed by employing the Kruskal Wallist test, Dunn's Multiple Comparison test and the wilcoxon signed rank test. In the control group, no contrast enhancement was demonstrated in the anterior or posterior chamber or in the vitreus fluid of the ipsilateral or contralateral eyeball on the 30 minutes MR images. The anterior chambers of the ipsilateral and contralateral eyeballs revealed delayed contrast enhancement on the 3 hour MR images. In the experimental group, the 30 minute-postembolization MR images were not different from those of the control group. The 30 minute-postembolization MR images demonstrated delayed contrast enhancement in the anterior chamber of the ipsilateral and contralateral eyeballs and in the posterior chamber of the ipsilateral eyeball. The delayed contrast enhancement of the posterior chamber of the ipsilateral eyeball was statistically significant (ρ < 0.05). The present study demonstrated significant contrast enhancement in the posterior chamber with infusion of the triolein emulsion, and this can serve as a model for blood-aqueous barrier studies

  5. Contaminant plume configuration and movement: an experimental model

    Science.gov (United States)

    Alencoao, A.; Reis, A.; Pereira, M. G.; Liberato, M. L. R.; Caramelo, L.; Amraoui, M.; Amorim, V.

    2009-04-01

    The relevance of Science and Technology in our daily routines makes it compulsory to educate citizens who have both scientific literacy and scientific knowledge. These will allow them to be intervening citizens in a constantly changing society. Thus, physical and natural sciences are included in school curricula, both in primary and secondary education, with the fundamental aim of developing in the students the skills, attitudes and knowledge needed for the understanding of the planet Earth and its real problems. On the other hand, teaching in Geosciences is more and more based on practical methodologies which use didactic material, sustaining teachers' pedagogical practices and facilitating students' learning tasks suggested on the syllabus defined for each school level. Themes related to exploring the different components of the Hydrological Cycle and themes related to natural environment protection and preservation, namely water resources and soil contamination by industrial and urban sewage are examples of subject matters included on the Portuguese syllabus. These topics motivated the conception and construction of experimental models for the study of the propagation of pollutants on a porous medium. The experimental models allow inducing a horizontal flux of water though different kinds of permeable substances (e.g. sand, silt), with contamination spots on its surface. These experimental activities facilitate the student to understand the flow path of contaminating substances on the saturated zone and to observe the contaminant plume configuration and movement. The activities are explored in a teaching and learning process perspective where the student builds its own knowledge through real question- problem based learning which relate Science, Technology and Society. These activities have been developed in the framework of project ‘Water in the Environment' (CV/PVI/0854) of the POCTI Program (Programa Operacional "Ciência, Tecnologia, Inovação") financed

  6. Experimental Investigation and Theoretical Modeling of Nanosilica Activity in Concrete

    Directory of Open Access Journals (Sweden)

    Han-Seung Lee

    2014-01-01

    Full Text Available This paper presents experimental investigations and theoretical modeling of the hydration reaction of nanosilica blended concrete with different water-to-binder ratios and different nanosilica replacement ratios. The developments of chemically bound water contents, calcium hydroxide contents, and compressive strength of Portland cement control specimens and nanosilica blended specimens were measured at different ages: 1 day, 3 days, 7 days, 14 days, and 28 days. Due to the pozzolanic reaction of nanosilica, the contents of calcium hydroxide in nanosilica blended pastes are considerably lower than those in the control specimens. Compared with the control specimens, the extent of compressive strength enhancement in the nanosilica blended specimens is much higher at early ages. Additionally, a blended cement hydration model that considers both the hydration reaction of cement and the pozzolanic reaction of nanosilica is proposed. The properties of nanosilica blended concrete during hardening were evaluated using the degree of hydration of cement and the reaction degree of nanosilica. The calculated chemically bound water contents, calcium hydroxide contents, and compressive strength were generally consistent with the experimental results.

  7. Tobacco experimental model to induce urinary bladder neoplasms

    Directory of Open Access Journals (Sweden)

    José Alexandre Colli Neto

    2014-01-01

    Full Text Available OBJECTIVE: to develop an experimental model of exposure to tobacco burning (cigarette products to assess the effects of its chronic use in relation to cancers of the bladder. METHODS: the animals were chronically exposed to the burning tobacco products in a semi-open chamber to simulate smoking. Thirty young Wistar rats were divided into two groups: one with 20 animals simulating smoking for six months, and ten not exposed control animals for the same period. After exposure by inhalation of cigarette smoke, animals were euthanized and subjected to histopathological study of the bladder wall. RESULTS: no tumor was found but mild and non significant alterations. The studies of hemo-oximetry (carboxyhemoglobin and methemoglobin and the concentration of carbon dioxide (CO2 confirm that the animals were exposed to high concentrations of tobacco smoke and its derivatives. CONCLUSION: no bladder mucosal neoplasia was found in the pathological study of animals. The developed experimental models were highly efficient, practical and easy to use and can be used in other similar studies to determine the harmful effects caused by smoking.

  8. Acute phase proteins in bovine milk in an experimental model of Staphylococcus aureus subclinical mastitis

    DEFF Research Database (Denmark)

    Eckersall, P D; Young, F J; Nolan, A M

    2006-01-01

    and serum amyloid A increase in serum during mastitis. The concentrations of these proteins were determined in an experimental model using a field strain of Staphylococcus aureus to induce subclinical mastitis in dairy cows. The expression of mRNA coding for these proteins was assessed and the presence of M......The objectives were to establish the origin of 2 acute phase proteins in milk during subclinical bovine mastitis and to characterize the relationship between those proteins in milk and blood. Haptoglobin (Hp) and mammary-associated serum amyloid A (M-SAA3) appear in milk during mastitis, whereas Hp...

  9. Active vibration absorber for the CSI evolutionary model - Design and experimental results. [Controls Structures Interaction

    Science.gov (United States)

    Bruner, Anne M.; Belvin, W. Keith; Horta, Lucas G.; Juang, Jer-Nan

    1991-01-01

    The development of control of large flexible structures technology must include practical demonstrations to aid in the understanding and characterization of controlled structures in space. To support this effort, a testbed facility has been developed to study practical implementation of new control technologies under realistic conditions. The paper discusses the design of a second order, acceleration feedback controller which acts as an active vibration absorber. This controller provides guaranteed stability margins for collocated sensor/actuator pairs in the absence of sensor/actuator dynamics and computational time delay. Experimental results in the presence of these factors are presented and discussed. The robustness of this design under model uncertainty is demonstrated.

  10. Physical characterization and kinetic modelling of matrix tablets of ...

    African Journals Online (AJOL)

    release mechanisms were characterized by kinetic modeling. Analytical ... findings demonstrate that both the desired physical characteristics and drug release profiles were obtained ..... on the compression, mechanical, and release properties.

  11. Experimental Characterization of LTE Wireless Links in High-Speed Trains

    Directory of Open Access Journals (Sweden)

    Tomás Domínguez-Bolaño

    2017-01-01

    Full Text Available Multimedia and data-based services experienced a nonstopping growth over the last few years. People are continuously on the move using devices to access multimedia contents or other data-based services. Due to this, railway companies are showing a great interest in deploying broadband mobile wireless networks in high-speed-trains with the aim of supporting both passenger services provisioning as well as automatic train control and signaling. Nowadays, the most widely used technology for communications between trains and the railway infrastructure is GSM for Railways (GSM-R; however, it has limited capabilities to support such advanced services. Due to its success in the mass market, Long Term Evolution (LTE seems to be the best candidate to substitute GSM-R. In this paper, we experimentally characterize the downlink between an LTE Evolved NodeB (eNodeB and a high-speed train in a commercial high-speed line. We consider two links: the one between the eNodeB and the antennas placed outdoors on the train roof, and the direct link between the eNodeB and a receiver inside the train. Such a characterization consists in assessing the path loss, the Signal to Noise Ratio, the K-Factor, the Power Delay Profile, the delay spread, and the Doppler Power Spectral Density.

  12. Experimental Characterization of Close-Emitter Interference in an Optical Camera Communication System.

    Science.gov (United States)

    Chavez-Burbano, Patricia; Guerra, Victor; Rabadan, Jose; Rodríguez-Esparragón, Dionisio; Perez-Jimenez, Rafael

    2017-07-04

    Due to the massive insertion of embedded cameras in a wide variety of devices and the generalized use of LED lamps, Optical Camera Communication (OCC) has been proposed as a practical solution for future Internet of Things (IoT) and smart cities applications. Influence of mobility, weather conditions, solar radiation interference, and external light sources over Visible Light Communication (VLC) schemes have been addressed in previous works. Some authors have studied the spatial intersymbol interference from close emitters within an OCC system; however, it has not been characterized or measured in function of the different transmitted wavelengths. In this work, this interference has been experimentally characterized and the Normalized Power Signal to Interference Ratio (NPSIR) for easily determining the interference in other implementations, independently of the selected system devices, has been also proposed. A set of experiments in a darkroom, working with RGB multi-LED transmitters and a general purpose camera, were performed in order to obtain the NPSIR values and to validate the deduced equations for 2D pixel representation of real distances. These parameters were used in the simulation of a wireless sensor network scenario in a small office, where the Bit Error Rate (BER) of the communication link was calculated. The experiments show that the interference of other close emitters in terms of the distance and the used wavelength can be easily determined with the NPSIR. Finally, the simulation validates the applicability of the deduced equations for scaling the initial results into real scenarios.

  13. Experimental Characterization of Close-Emitter Interference in an Optical Camera Communication System

    Science.gov (United States)

    Chavez-Burbano, Patricia; Rabadan, Jose; Perez-Jimenez, Rafael

    2017-01-01

    Due to the massive insertion of embedded cameras in a wide variety of devices and the generalized use of LED lamps, Optical Camera Communication (OCC) has been proposed as a practical solution for future Internet of Things (IoT) and smart cities applications. Influence of mobility, weather conditions, solar radiation interference, and external light sources over Visible Light Communication (VLC) schemes have been addressed in previous works. Some authors have studied the spatial intersymbol interference from close emitters within an OCC system; however, it has not been characterized or measured in function of the different transmitted wavelengths. In this work, this interference has been experimentally characterized and the Normalized Power Signal to Interference Ratio (NPSIR) for easily determining the interference in other implementations, independently of the selected system devices, has been also proposed. A set of experiments in a darkroom, working with RGB multi-LED transmitters and a general purpose camera, were performed in order to obtain the NPSIR values and to validate the deduced equations for 2D pixel representation of real distances. These parameters were used in the simulation of a wireless sensor network scenario in a small office, where the Bit Error Rate (BER) of the communication link was calculated. The experiments show that the interference of other close emitters in terms of the distance and the used wavelength can be easily determined with the NPSIR. Finally, the simulation validates the applicability of the deduced equations for scaling the initial results into real scenarios. PMID:28677613

  14. Production and partial characterization of lipases from a newly isolated Penicillium sp. using experimental design.

    Science.gov (United States)

    Wolski, E; Rigo, E; Di Luccio, M; Oliveira, J V; de Oliveira, D; Treichel, H

    2009-07-01

    The objective of this work was to investigate the lipase production by a newly isolated Penicillium sp., using experimental design technique, in submerged fermentation using a medium based on peptone, yeast extract, NaCl and olive oil, as well as to characterize the crude enzymatic extracts obtained. Lipase activity values of 9.5 U ml(-1) in 96 h of fermentation was obtained at the maximized operational conditions of peptone, yeast extract, NaCl and olive oil concentrations (g l(-1)) of 20.0, 5.0, 5.0 and of 10.0 respectively. The partial characterization of crude enzymatic extract obtained by submerged fermentation showed optimum activity at pH range from 4.9 to 5.5 and temperature from 37 degrees C to 42 degrees C. The crude extract maintained its initial activity at freezing temperatures up to 100 days. A newly isolated strain of Penicillium sp. used in this work yielded good lipase activities compared to the literature. The growing interest in lipase production is related to the potential biotechnological applications that these enzymes present. New lipase producers are relevant to finding enzymes with different catalytic properties of commercial interest could be obtained, without using genetically modified organisms (GMO).

  15. Damage characterization and modeling of a 7075-T651 aluminum plate

    International Nuclear Information System (INIS)

    Jordon, J.B.; Horstemeyer, M.F.; Solanki, K.; Bernard, J.D.; Berry, J.T.; Williams, T.N.

    2009-01-01

    In this paper, the damage-induced anisotropy arising from material microstructure heterogeneities at two different length scales was characterized and modeled for a wrought aluminum alloy. Experiments were performed on a 7075-T651 aluminum alloy plate using sub-standard tensile specimens in three different orientations with respect to the rolling direction. Scanning electron microscopy was employed to characterize the stereology of the final damage state in terms of cracked and or debonded particles. A physically motivated internal state variable continuum model was used to predict fracture by incorporating material microstructural features. The continuum model showed good comparisons to the experimental data by capturing the damage-induced anisotropic material response. Estimations of the mechanical stress-strain response, material damage histories, and final failure were numerically calculated and experimentally validated thus demonstrating that the final failure state was strongly dependent on the constituent particle morphology.

  16. A new experimental setup to characterize the dynamic mechanical behaviour of ballistic yarns

    International Nuclear Information System (INIS)

    Chevalier, C; Kerisit, C; Faderl, N; Klavzar, A; Boussu, F; Coutellier, D

    2016-01-01

    Fabrics have been widely used as part of ballistic protections since the 1970s and the development of new ballistic solutions made from fabrics need numerical simulations, in order to predict the performance of the ballistic protection. The performances and the induced mechanisms in ballistic fabrics during an impact depend on the weaving parameters and also on the inner parameters of the yarns used inside these structures. Thus, knowing the dynamic behaviour of yarn is essential to determine the ballistic behaviour of fabrics during an impact. Two major experimental devices exist and are used to test ballistic yarns in a dynamic uniaxial tension. The first one corresponds to the Split Hopkinson Tensile Bars device, which is commonly used to characterize the mechanical properties of materials in uniaxial tension and under high loading. The second one is the transversal impact device. The real conditions of ballistic impact can be realized with this device. Then, this paper deals with a new experimental setup developed in our laboratory and called the ‘tensile impact test for yarn’ (TITY) device. With this device, specific absorbed energy measurements of para-aramid yarns (336 Tex, Twaron ™ , 1000 filaments) have been carried out and revealed that static and dynamic properties of para-aramid are different. (paper)

  17. Markov transition probability-based network from time series for characterizing experimental two-phase flow

    International Nuclear Information System (INIS)

    Gao Zhong-Ke; Hu Li-Dan; Jin Ning-De

    2013-01-01

    We generate a directed weighted complex network by a method based on Markov transition probability to represent an experimental two-phase flow. We first systematically carry out gas—liquid two-phase flow experiments for measuring the time series of flow signals. Then we construct directed weighted complex networks from various time series in terms of a network generation method based on Markov transition probability. We find that the generated network inherits the main features of the time series in the network structure. In particular, the networks from time series with different dynamics exhibit distinct topological properties. Finally, we construct two-phase flow directed weighted networks from experimental signals and associate the dynamic behavior of gas-liquid two-phase flow with the topological statistics of the generated networks. The results suggest that the topological statistics of two-phase flow networks allow quantitative characterization of the dynamic flow behavior in the transitions among different gas—liquid flow patterns. (general)

  18. Experimental characterization of solid particle transport by slug flow using Particle Image Velocimetry

    International Nuclear Information System (INIS)

    Goharzadeh, A; Rodgers, P

    2009-01-01

    This paper presents an experimental study of gas-liquid slug flow on solid particle transport inside a horizontal pipe with two types of experiments conducted. The influence of slug length on solid particle transportation is characterized using high speed photography. Using combined Particle Image Velocimetry (PIV) with Refractive Index Matching (RIM) and fluorescent tracers (two-phase oil-air loop) the velocity distribution inside the slug body is measured. Combining these experimental analyses, an insight is provided into the physical mechanism of solid particle transportation due to slug flow. It was observed that the slug body significantly influences solid particle mobility. The physical mechanism of solid particle transportation was found to be discontinuous. The inactive region (in terms of solid particle transport) upstream of the slug nose was quantified as a function of gas-liquid composition and solid particle size. Measured velocity distributions showed a significant drop in velocity magnitude immediately upstream of the slug nose and therefore the critical velocity for solid particle lifting is reached further upstream.

  19. Proton beam characterization in the experimental room of the Trento Proton Therapy facility

    Science.gov (United States)

    Tommasino, F.; Rovituso, M.; Fabiano, S.; Piffer, S.; Manea, C.; Lorentini, S.; Lanzone, S.; Wang, Z.; Pasini, M.; Burger, W. J.; La Tessa, C.; Scifoni, E.; Schwarz, M.; Durante, M.

    2017-10-01

    As proton therapy is becoming an established treatment methodology for cancer patients, the number of proton centres is gradually growing worldwide. The economical effort for building these facilities is motivated by the clinical aspects, but might be also supported by the potential relevance for the research community. Experiments with high-energy protons are needed not only for medical physics applications, but represent also an essential part of activities dedicated to detector development, space research, radiation hardness tests, as well as of fundamental research in nuclear and particle physics. Here we present the characterization of the beam line installed in the experimental room of the Trento Proton Therapy Centre (Italy). Measurements of beam spot size and envelope, range verification and proton flux were performed in the energy range between 70 and 228 MeV. Methods for reducing the proton flux from typical treatments values of 106-109 particles/s down to 101-105 particles/s were also investigated. These data confirm that a proton beam produced in a clinical centre build by a commercial company can be exploited for a broad spectrum of experimental activities. The results presented here will be used as a reference for future experiments.

  20. Experimental characterization of the COndensation PArticle counting System for high altitude aircraft-borne application

    Directory of Open Access Journals (Sweden)

    S. Borrmann

    2009-06-01

    Full Text Available A characterization of the ultra-fine aerosol particle counter COPAS (COndensation PArticle counting System for operation on board the Russian high altitude research aircraft M-55 Geophysika is presented. The COPAS instrument consists of an aerosol inlet and two dual-channel continuous flow Condensation Particle Counters (CPCs operated with the chlorofluorocarbon FC-43. It operates at pressures between 400 and 50 hPa for aerosol detection in the particle diameter (dp range from 6 nm up to 1 μm. The aerosol inlet, designed for the M-55, is characterized with respect to aspiration, transmission, and transport losses. The experimental characterization of counting efficiencies of three CPCs yields dp50 (50% detection particle diameter of 6 nm, 11 nm, and 15 nm at temperature differences (ΔT between saturator and condenser of 17°C, 30°C, and 33°C, respectively. Non-volatile particles are quantified with a fourth CPC, with dp50=11 nm. It includes an aerosol heating line (250°C to evaporate H2SO4-H2O particles of 11 nm<dp<200 nm at pressures between 70 and 300 hPa. An instrumental in-flight inter-comparison of the different COPAS CPCs yields correlation coefficients of 0.996 and 0.985. The particle emission index for the M-55 in the range of 1.4–8.4×1016 kg−1 fuel burned has been estimated based on measurements of the Geophysika's own exhaust.

  1. Energy materials. Advances in characterization, modelling and application

    International Nuclear Information System (INIS)

    Andersen, N.H.; Eldrup, M.; Hansen, N.; Juul Jensen, D.; Nielsen, E.M.; Nielsen, S.F.; Soerensen, B.F.; Pedersen, A.S.; Vegge, T.; West, S.S.

    2008-01-01

    Energy-related topics in the modern world and energy research programmes cover the range from basic research to applications and structural length scales from micro to macro. Materials research and development is a central part of the energy area as break-throughs in many technologies depend on a successful development and validation of new or advanced materials. The Symposium is organized by the Materials Research Department at Risoe DTU - National Laboratory for Sustainable Energy. The Department concentrates on energy problems combining basic and applied materials research with special focus on the key topics: wind, fusion, superconductors and hydrogen. The symposium is based on these key topics and focus on characterization of materials for energy applying neutron, X-ray and electron diffraction. Of special interest is research carried out at large facilities such as reactors and synchrotrons, supplemented by other experimental techniques and modelling on different length scales that underpins experiments. The Proceedings contain 15 key note presentations and 30 contributed presentations, covering the abovementioned key topics relevant for the energy materials. The contributions clearly show the importance of materials research when developing sustainable energy technologies and also that many challenges remain to be approached. (BA)

  2. Application of Iterative Robust Model-based Optimal Experimental Design for the Calibration of Biocatalytic Models

    DEFF Research Database (Denmark)

    Van Daele, Timothy; Gernaey, Krist V.; Ringborg, Rolf Hoffmeyer

    2017-01-01

    The aim of model calibration is to estimate unique parameter values from available experimental data, here applied to a biocatalytic process. The traditional approach of first gathering data followed by performing a model calibration is inefficient, since the information gathered during...... experimentation is not actively used to optimise the experimental design. By applying an iterative robust model-based optimal experimental design, the limited amount of data collected is used to design additional informative experiments. The algorithm is used here to calibrate the initial reaction rate of an ω......-transaminase catalysed reaction in a more accurate way. The parameter confidence region estimated from the Fisher Information Matrix is compared with the likelihood confidence region, which is a more accurate, but also a computationally more expensive method. As a result, an important deviation between both approaches...

  3. A computational modeling approach for the characterization of mechanical properties of 3D alginate tissue scaffolds.

    Science.gov (United States)

    Nair, K; Yan, K C; Sun, W

    2008-01-01

    Scaffold guided tissue engineering is an innovative approach wherein cells are seeded onto biocompatible and biodegradable materials to form 3-dimensional (3D) constructs that, when implanted in the body facilitate the regeneration of tissue. Tissue scaffolds act as artificial extracellular matrix providing the environment conducive for tissue growth. Characterization of scaffold properties is necessary to understand better the underlying processes involved in controlling cell behavior and formation of functional tissue. We report a computational modeling approach to characterize mechanical properties of 3D gellike biomaterial, specifically, 3D alginate scaffold encapsulated with cells. Alginate inherent nonlinearity and variations arising from minute changes in its concentration and viscosity make experimental evaluation of its mechanical properties a challenging and time consuming task. We developed an in silico model to determine the stress-strain relationship of alginate based scaffolds from experimental data. In particular, we compared the Ogden hyperelastic model to other hyperelastic material models and determined that this model was the most suitable to characterize the nonlinear behavior of alginate. We further propose a mathematical model that represents the alginate material constants in Ogden model as a function of concentrations and viscosity. This study demonstrates the model capability to predict mechanical properties of 3D alginate scaffolds.

  4. Integral Reactor Containment Condensation Model and Experimental Validation

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Qiao [Oregon State Univ., Corvallis, OR (United States); Corradini, Michael [Univ. of Wisconsin, Madison, WI (United States)

    2016-05-02

    This NEUP funded project, NEUP 12-3630, is for experimental, numerical and analytical studies on high-pressure steam condensation phenomena in a steel containment vessel connected to a water cooling tank, carried out at Oregon State University (OrSU) and the University of Wisconsin at Madison (UW-Madison). In the three years of investigation duration, following the original proposal, the planned tasks have been completed: (1) Performed a scaling study for the full pressure test facility applicable to the reference design for the condensation heat transfer process during design basis accidents (DBAs), modified the existing test facility to route the steady-state secondary steam flow into the high pressure containment for controllable condensation tests, and extended the operations at negative gage pressure conditions (OrSU). (2) Conducted a series of DBA and quasi-steady experiments using the full pressure test facility to provide a reliable high pressure condensation database (OrSU). (3) Analyzed experimental data and evaluated condensation model for the experimental conditions, and predicted the prototypic containment performance under accidental conditions (UW-Madison). A film flow model was developed for the scaling analysis, and the results suggest that the 1/3 scaled test facility covers large portion of laminar film flow, leading to a lower average heat transfer coefficient comparing to the prototypic value. Although it is conservative in reactor safety analysis, the significant reduction of heat transfer coefficient (50%) could under estimate the prototypic condensation heat transfer rate, resulting in inaccurate prediction of the decay heat removal capability. Further investigation is thus needed to quantify the scaling distortion for safety analysis code validation. Experimental investigations were performed in the existing MASLWR test facility at OrST with minor modifications. A total of 13 containment condensation tests were conducted for pressure

  5. Experimental investigation and mathematical modeling of triode PEM fuel cells

    International Nuclear Information System (INIS)

    Martino, E.; Koilias, G.; Athanasiou, M.; Katsaounis, A.; Dimakopoulos, Y.; Tsamopoulos, J.; Vayenas, C.G.

    2017-01-01

    Highlights: •The triode fuel cell operation was tested using novel comb-type electrode designs. •Triode operation enhances the PEMFC power output by up to 500%. •Power output enhancement exceeds auxiliary power by up to 20%. •Good agreement with mathematical model based on the laws of Kirchhoff. •Proton fluxes in the membrane found via solution of the Nernst Planck equation -- Abstract: The triode operation of humidified PEM fuel cells has been investigated both with pure H 2 and with CO poisoned H 2 feed over commercial Vulcan supported Pt(30%)-Ru(15%) anodes. It was found that triode operation, which involves the use of a third, auxiliary, electrode, leads to up to 400% power output increase with the same CO poisoned H 2 gas feed. At low current densities, the power increase is accompanied by an increase in overall thermodynamic efficiency. A mathematical model, based on Kirchhoff’s laws, has been developed which is in reasonably good agreement with the experimental results. In order to gain some additional insight into the mechanism of triode operation, the model has been also extended to describe the potential distribution inside the Nafion membrane via the numerical solution of the Nernst-Planck equation. Both model and experiment have shown the critical role of minimizing the auxiliary-anode or auxiliary-cathode resistance, and this has led to improved comb-shaped anode or cathode electrode geometries.

  6. The Non-Human Primate Experimental Glaucoma Model

    Science.gov (United States)

    Burgoyne, Claude F.

    2015-01-01

    The purpose of this report is to summarize the current strengths and weaknesses of the non-human primate (NHP) experimental glaucoma (EG) model through sections devoted to its history, methods, important findings, alternative optic neuropathy models and future directions. NHP EG has become well established for studying human glaucoma in part because the NHP optic nerve head (ONH) shares a close anatomic association with the human ONH and because it provides the only means of systematically studying the very earliest visual system responses to chronic IOP elevation, i.e. the conversion from ocular hypertension to glaucomatous damage. However, NHPs are impractical for studies that require large animal numbers, demonstrate spontaneous glaucoma only rarely, do not currently provide a model of the neuropathy at normal levels of IOP, and cannot easily be genetically manipulated, except through tissue-specific, viral vectors. The goal of this summary is to direct NHP EG and non-NHP EG investigators to the previous, current and future accomplishment of clinically relevant knowledge in this model. PMID:26070984

  7. Autonomous learning derived from experimental modeling of physical laws.

    Science.gov (United States)

    Grabec, Igor

    2013-05-01

    This article deals with experimental description of physical laws by probability density function of measured data. The Gaussian mixture model specified by representative data and related probabilities is utilized for this purpose. The information cost function of the model is described in terms of information entropy by the sum of the estimation error and redundancy. A new method is proposed for searching the minimum of the cost function. The number of the resulting prototype data depends on the accuracy of measurement. Their adaptation resembles a self-organized, highly non-linear cooperation between neurons in an artificial NN. A prototype datum corresponds to the memorized content, while the related probability corresponds to the excitability of the neuron. The method does not include any free parameters except objectively determined accuracy of the measurement system and is therefore convenient for autonomous execution. Since representative data are generally less numerous than the measured ones, the method is applicable for a rather general and objective compression of overwhelming experimental data in automatic data-acquisition systems. Such compression is demonstrated on analytically determined random noise and measured traffic flow data. The flow over a day is described by a vector of 24 components. The set of 365 vectors measured over one year is compressed by autonomous learning to just 4 representative vectors and related probabilities. These vectors represent the flow in normal working days and weekends or holidays, while the related probabilities correspond to relative frequencies of these days. This example reveals that autonomous learning yields a new basis for interpretation of representative data and the optimal model structure. Copyright © 2012 Elsevier Ltd. All rights reserved.

  8. Mass spectrometry analysis of hepcidin peptides in experimental mouse models.

    Directory of Open Access Journals (Sweden)

    Harold Tjalsma

    Full Text Available The mouse is a valuable model for unravelling the role of hepcidin in iron homeostasis, however, such studies still report hepcidin mRNA levels as a surrogate marker for bioactive hepcidin in its pivotal function to block ferroportin-mediated iron transport. Here, we aimed to assess bioactive mouse Hepcidin-1 (Hep-1 and its paralogue Hepcidin-2 (Hep-2 at the peptide level. To this purpose, Fourier transform ion cyclotron resonance (FTICR and tandem-MS was used for hepcidin identification, after which a time-of-flight (TOF MS-based methodology was exploited to routinely determine Hep-1 and -2 levels in mouse serum and urine. This method was biologically validated by hepcidin assessment in: i 3 mouse strains (C57Bl/6; DBA/2 and BABL/c upon stimulation with intravenous iron and LPS, ii homozygous Hfe knock out, homozygous transferrin receptor 2 (Y245X mutated mice and double affected mice, and iii mice treated with a sublethal hepatotoxic dose of paracetamol. The results showed that detection of Hep-1 was restricted to serum, whereas Hep-2 and its presumed isoforms were predominantly present in urine. Elevations in serum Hep-1 and urine Hep-2 upon intravenous iron or LPS were only moderate and varied considerably between mouse strains. Serum Hep-1 was decreased in all three hemochromatosis models, being lowest in the double affected mice. Serum Hep-1 levels correlated with liver hepcidin-1 gene expression, while acute liver damage by paracetamol depleted Hep-1 from serum. Furthermore, serum Hep-1 appeared to be an excellent indicator of splenic iron accumulation. In conclusion, Hep-1 and Hep-2 peptide responses in experimental mouse agree with the known biology of hepcidin mRNA regulators, and their measurement can now be implemented in experimental mouse models to provide novel insights in post-transcriptional regulation, hepcidin function, and kinetics.

  9. Human, Social, Cultural Behavior (HSCB) Modeling Workshop I: Characterizing the Capability Needs for HSCB Modeling

    Science.gov (United States)

    2008-07-01

    The expectations correspond to different roles individuals perform SocialConstructionis Social constructionism is a school of thought Peter L...HUMAN, SOCIAL , CULTURAL BEHAVIOR (HSCB) MODELING WORKSHOP I: CHARACTERIZING THE CAPABILITY NEEDS FOR HSCB MODELING FINAL REPORT... Social , Cultural Behavior (HSCB) Modeling Workshop I: Characterizing the Capability Needs for HSCB Modeling 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c

  10. Modelling and Experimental Investigation of an Active Damper

    Directory of Open Access Journals (Sweden)

    Rafael Luís Teixeira

    2006-01-01

    Full Text Available This paper presents a validation methodology of the dynamic behavior of an active viscous damper. The damper has two flexible metallic bellows connected to a rigid reservoir filled with fluid. When one of the bellows is connected to a vibrating structure a periodic flow passes through a variable internal orifice and the damping effect is produced. The size of the orifice is adjusted by a controlled linear piezoelectric actuator that positions the conical core into a conical cavity. The device finite element structural model consists of the valve body and its conical core that are assumed rigid and the flexible bellows are represented by two pistons with elastic suspensions. The flow developed inside the damper is modeled considering the fluid-structure interation, using the Lagrangean-Eulerian formulation. To validate the proposed model a prototype was constructed and experimental tests and numerical simulations are accomplished in the time domain, applying harmonic excitations. The results are compared using curves that relate the damping coefficient with the orifice size and with the input velocity applied at the bellows face. However, for the proper control design and system operation, the direct use of the finite element model becomes unviable due to its high computational time. Then, a reduced second order discrete dynamic model for the damper was developed. The model parameters are identified by analysis in the frequency domain, using impulsive excitation force, for constant and variable orifice sizes. At low excitation frequencies, the damper prototype behaves like a single degree of freedom system which damping factor changes with the orifice size A fuzzy controller was designed and it generates the orifice reference size associated to the desired damping factor. The active system presented better performance when compared to the passive one.

  11. Characterization of an erbium doped fiber amplifier starting from its experimental parameters; Caracterizacion de un amplificador de fibra dopada con erbio a partir de sus parametros experimentales

    Energy Technology Data Exchange (ETDEWEB)

    Bello J, M.; Kuzin, E.A.; Ibarra E, B. [Instituto Nacional de Astrofisica, Optica y Electronica (INAOE), Luis Enrique Erro No. 1, TonantzintIa, 72000 Puebla (Mexico); Tellez G, R. [Instituto Mexicano del Petroleo, Eje Central Lazaro Cardenas No 152, Delegacion Gustavo A. Madero, 07730 Mexico D.F. (Mexico)]. e-mail: mabello@inaoep.mx

    2007-07-01

    In this paper we describe a method to characterize the gain of an erbium-doped fiber amplifier (EDFA) through the numerical simulation of the signal beam along the amplifier. The simulation is based on a model constituted by the propagation and rate equations for an erbium-doped fiber. The manipulation of these equations allows us to regroup the parameters present in an EDFA, which we have named the A, B, C, D parameters, and they can be obtained experimentally from an erbium-doped fiber. Experimental results show that the measurement of these parameters allow us to estimate with very good correspondence the amplifier gain. (Author)

  12. Characterizing emerging industrial technologies in energy models

    Energy Technology Data Exchange (ETDEWEB)

    Laitner, John A. (Skip); Worrell, Ernst; Galitsky, Christina; Hanson, Donald A.

    2003-07-29

    Conservation supply curves are a common tool in economic analysis. As such, they provide an important opportunity to include a non-linear representation of technology and technological change in economy-wide models. Because supply curves are closely related to production isoquants, we explore the possibility of using bottom-up technology assessments to inform top-down representations of energy models of the U.S. economy. Based on a recent report by LBNL and ACEEE on emerging industrial technologies within the United States, we have constructed a supply curve for 54 such technologies for the year 2015. Each of the selected technologies has been assessed with respect to energy efficiency characteristics, likely energy savings by 2015, economics, and environmental performance, as well as needs for further development or implementation of the technology. The technical potential for primary energy savings of the 54 identified technologies is equal to 3.54 Quads, or 8.4 percent of the assume d2015 industrial energy consumption. Based on the supply curve, assuming a discount rate of 15 percent and 2015 prices as forecasted in the Annual Energy Outlook2002, we estimate the economic potential to be 2.66 Quads - or 6.3 percent of the assumed forecast consumption for 2015. In addition, we further estimate how much these industrial technologies might contribute to standard reference case projections, and how much additional energy savings might be available assuming a different mix of policies and incentives. Finally, we review the prospects for integrating the findings of this and similar studies into standard economic models. Although further work needs to be completed to provide the necessary link between supply curves and production isoquants, it is hoped that this link will be a useful starting point for discussion with developers of energy-economic models.

  13. Electroweak Calibration of the Higgs Characterization Model

    CERN Multimedia

    CERN. Geneva

    2015-01-01

    I will present the preliminary results of histogram fits using the Higgs Combine histogram fitting package. These fits can be used to estimate the effects of electroweak contributions to the p p -> H mu+ mu- Higgs production channel and calibrate Beyond Standard Model (BSM) simulations which ignore these effects. I will emphasize my findings' significance in the context of other research here at CERN and in the broader world of high energy physics.

  14. Experimental investigation and mechanistic modelling of dilute bubbly bulk boiling

    Energy Technology Data Exchange (ETDEWEB)

    Kutnjak, Josip

    2013-06-27

    During evaporation the geometric shape of the vapour is not described using thermodynamics. In bubbly flows the bubble shape is considered spheric with small diameters and changing into various shapes upon growth. The heat and mass transfer happens at the interfacial area. The forces acting on the bubbles depend on the bubble diameter and shape. In this work the prediction of the bubble diameter and/or bubble number density in bulk boiling was considered outside the vicinity of the heat input area. Thus the boiling effects that happened inside the nearly saturated bulk were under investigation. This situation is relevant for nuclear safety analysis concerning a stagnant coolant in the spent fuel pool. In this research project a new experimental set-up to investigate was built. The experimental set-up consists of an instrumented, partly transparent, high and slender boiling container for visual observation. The direct visual observation of the boiling phenomena is necessary for the identification of basic mechanisms, which should be incorporated in the simulation model. The boiling process has been recorded by means of video images and subsequently was evaluated by digital image processing methods, and by that data concerning the characteristics of the boiling process were generated for the model development and validation. Mechanistic modelling is based on the derivation of relevant mechanisms concluded from observation, which is in line with physical knowledge. In this context two mechanisms were identified; the growth/-shrink mechanism (GSM) of the vapour bubbles and sudden increases of the bubble number density. The GSM was implemented into the CFD-Code ANSYS-CFX using the CFX Expression Language (CEL) by calculation of the internal bubble pressure using the Young-Laplace-Equation. This way a hysteresis is realised as smaller bubbles have an increased internal pressure. The sudden increases of the bubble number density are explainable by liquid super

  15. Experimental investigation and mechanistic modelling of dilute bubbly bulk boiling

    International Nuclear Information System (INIS)

    Kutnjak, Josip

    2013-01-01

    During evaporation the geometric shape of the vapour is not described using thermodynamics. In bubbly flows the bubble shape is considered spheric with small diameters and changing into various shapes upon growth. The heat and mass transfer happens at the interfacial area. The forces acting on the bubbles depend on the bubble diameter and shape. In this work the prediction of the bubble diameter and/or bubble number density in bulk boiling was considered outside the vicinity of the heat input area. Thus the boiling effects that happened inside the nearly saturated bulk were under investigation. This situation is relevant for nuclear safety analysis concerning a stagnant coolant in the spent fuel pool. In this research project a new experimental set-up to investigate was built. The experimental set-up consists of an instrumented, partly transparent, high and slender boiling container for visual observation. The direct visual observation of the boiling phenomena is necessary for the identification of basic mechanisms, which should be incorporated in the simulation model. The boiling process has been recorded by means of video images and subsequently was evaluated by digital image processing methods, and by that data concerning the characteristics of the boiling process were generated for the model development and validation. Mechanistic modelling is based on the derivation of relevant mechanisms concluded from observation, which is in line with physical knowledge. In this context two mechanisms were identified; the growth/-shrink mechanism (GSM) of the vapour bubbles and sudden increases of the bubble number density. The GSM was implemented into the CFD-Code ANSYS-CFX using the CFX Expression Language (CEL) by calculation of the internal bubble pressure using the Young-Laplace-Equation. This way a hysteresis is realised as smaller bubbles have an increased internal pressure. The sudden increases of the bubble number density are explainable by liquid super

  16. PVT characterization and viscosity modeling and prediction of crude oils

    DEFF Research Database (Denmark)

    Cisneros, Eduardo Salvador P.; Dalberg, Anders; Stenby, Erling Halfdan

    2004-01-01

    In previous works, the general, one-parameter friction theory (f-theory), models have been applied to the accurate viscosity modeling of reservoir fluids. As a base, the f-theory approach requires a compositional characterization procedure for the application of an equation of state (EOS), in most...... pressure, is also presented. The combination of the mass characterization scheme presented in this work and the f-theory, can also deliver accurate viscosity modeling results. Additionally, depending on how extensive the compositional characterization is, the approach,presented in this work may also...... deliver accurate viscosity predictions. The modeling approach presented in this work can deliver accurate viscosity and density modeling and prediction results over wide ranges of reservoir conditions, including the compositional changes induced by recovery processes such as gas injection....

  17. Experimental Modeling of the Formation of Saucer-Shaped sills

    Science.gov (United States)

    Galland, O.; Planke, S.; Malthe-Sorenssen, A.

    2007-12-01

    Many magma intrusions in sedimentary basins are sills, and especially saucer-shaped sills. These features are observed in many places (i.e. South Africa; the Norwegian and North Sea; Siberia; Argentina). Sand injectites exhibit similar geometries. The occurrence of such features in so various settings suggests that their emplacement results from fundamental processes in sedimentary basins. To understand such processes, we performed experimental modeling of saucer-shaped sill emplacement. The experiments consist of injecting a molten low viscosity vegetable oil (model magma) at a constant flow rate into a fine-grained Coulomb silica flour (model rock). When the oil starts intruding, the initially flat surface of the model inflates and forms a smooth dome. At the end of the experiment, the oil erupts at the edge of the dome. After the experiment, the oil cools and solidifies, the resulting solid intrusion is unburied and exposed, and its upper surface digitalized. For our purpose, we did our experiments without external deformation. We performed two series of experiments with varying depth of injection. The first series consisted of injection into a homogeneous medium. The resulting intrusions were cone-sheets and dykes. The second series consisted of heterogeneous models where the heterogeneity was a weak layer made of a flexible net. The resulting intrusions were made of (1) a horizontal basal sill emplaced along the weakness, and (2) inclined sheets nucleating at the edges of the basal sill and propagating upward and outward. The inclined sheets exhibited a convex shape, i.e. a decreasing slope outward. In addition, the deeper the sills emplaced, the larger they were. Our experimental results are consistent with saucer-shaped features in nature. We infer from our results that the transition between the basal sills and the inclined sheets results from a transition of emplacement processes. We suggest that the basal sill emplace by open (mode I) fracturing, whereas

  18. Human embryonic stem cell lines model experimental human cytomegalovirus latency.

    Science.gov (United States)

    Penkert, Rhiannon R; Kalejta, Robert F

    2013-05-28

    Herpesviruses are highly successful pathogens that persist for the lifetime of their hosts primarily because of their ability to establish and maintain latent infections from which the virus is capable of productively reactivating. Human cytomegalovirus (HCMV), a betaherpesvirus, establishes latency in CD34(+) hematopoietic progenitor cells during natural infections in the body. Experimental infection of CD34(+) cells ex vivo has demonstrated that expression of the viral gene products that drive productive infection is silenced by an intrinsic immune defense mediated by Daxx and histone deacetylases through heterochromatinization of the viral genome during the establishment of latency. Additional mechanistic details about the establishment, let alone maintenance and reactivation, of HCMV latency remain scarce. This is partly due to the technical challenges of CD34(+) cell culture, most notably, the difficulty in preventing spontaneous differentiation that drives reactivation and renders them permissive for productive infection. Here we demonstrate that HCMV can establish, maintain, and reactivate in vitro from experimental latency in cultures of human embryonic stem cells (ESCs), for which spurious differentiation can be prevented or controlled. Furthermore, we show that known molecular aspects of HCMV latency are faithfully recapitulated in these cells. In total, we present ESCs as a novel, tractable model for studies of HCMV latency.

  19. [Intestinal lengthening techniques: an experimental model in dogs].

    Science.gov (United States)

    Garibay González, Francisco; Díaz Martínez, Daniel Alberto; Valencia Flores, Alejandro; González Hernández, Miguel Angel

    2005-01-01

    To compare two intestinal lengthening procedures in an experimental dog model. Intestinal lengthening is one of the methods for gastrointestinal reconstruction used for treatment of short bowel syndrome. The modification to the Bianchi's technique is an alternative. The modified technique decreases the number of anastomoses to a single one, thus reducing the risk of leaks and strictures. To our knowledge there is not any clinical or experimental report that studied both techniques, so we realized the present report. Twelve creole dogs were operated with the Bianchi technique for intestinal lengthening (group A) and other 12 creole dogs from the same race and weight were operated by the modified technique (Group B). Both groups were compared in relation to operating time, difficulties in technique, cost, intestinal lengthening and anastomoses diameter. There were no statistical difference in the anastomoses diameter (A = 9.0 mm vs. B = 8.5 mm, p = 0.3846). Operating time (142 min vs. 63 min) cost and technique difficulties were lower in group B (p anastomoses (of Group B) and intestinal segments had good blood supply and were patent along their full length. Bianchi technique and the modified technique offer two good reliable alternatives for the treatment of short bowel syndrome. The modified technique improved operating time, cost and technical issues.

  20. An experimental model for the surgical correction of tracheomalacia.

    Science.gov (United States)

    Shaha, A R; Burnett, C; DiMaio, T; Jaffe, B M

    1991-10-01

    Tracheomalacia may result from large intrathoracic goiters. Due to the chronic compression, particularly within the confines of the thoracic inlet, the tracheal wall weakens, with disintegration of some of the cartilaginous rings. Tracheomalacia can cause acute airway distress, particularly during the post-operative period, and may occasionally result in death. The other major cause of tracheomalacia is related to either prolonged endotracheal intubation or over-inflation of the tracheostomy cuff. While various techniques such as internal stenting, external support devices, tracheostomy, and tracheal resection have been used based on individual circumstances, no one method appears to be perfect. To further study this difficult problem, an experimental model of tracheomalacia was created in eight dogs. Six to seven rings of the tracheal cartilages were dissected submucosally. More than half of the circumference of the tracheal rings was resected. The tracheal walls were reconstructed with polytetrafluoroethylene (PTFE) grafts. The grafts strengthened the tracheal wall without causing luminal constriction. Tracheostomy was not performed on any of the dogs. All dogs tolerated the procedure well and were extubated at the conclusion of the experiment. The dogs were followed for 4 to 6 months and then sacrificed so that the tracheal wall could be examined histologically. There was considerable fibrosis leading to stiff neotrachea. The results of this experimental technique for prosthetic reconstruction to counteract problems simulating tracheomalacia are very encouraging.

  1. Strain rate sensitivity of the tensile strength of two silicon carbides: experimental evidence and micromechanical modelling.

    Science.gov (United States)

    Zinszner, Jean-Luc; Erzar, Benjamin; Forquin, Pascal

    2017-01-28

    Ceramic materials are commonly used to design multi-layer armour systems thanks to their favourable physical and mechanical properties. However, during an impact event, fragmentation of the ceramic plate inevitably occurs due to its inherent brittleness under tensile loading. Consequently, an accurate model of the fragmentation process is necessary in order to achieve an optimum design for a desired armour configuration. In this work, shockless spalling tests have been performed on two silicon carbide grades at strain rates ranging from 10 3 to 10 4  s -1 using a high-pulsed power generator. These spalling tests characterize the tensile strength strain rate sensitivity of each ceramic grade. The microstructural properties of the ceramics appear to play an important role on the strain rate sensitivity and on the dynamic tensile strength. Moreover, this experimental configuration allows for recovering damaged, but unbroken specimens, giving unique insight on the fragmentation process initiated in the ceramics. All the collected data have been compared with corresponding results of numerical simulations performed using the Denoual-Forquin-Hild anisotropic damage model. Good agreement is observed between numerical simulations and experimental data in terms of free surface velocity, size and location of the damaged zones along with crack density in these damaged zones.This article is part of the themed issue 'Experimental testing and modelling of brittle materials at high strain rates'. © 2016 The Author(s).

  2. Strain rate sensitivity of the tensile strength of two silicon carbides: experimental evidence and micromechanical modelling

    Science.gov (United States)

    Erzar, Benjamin

    2017-01-01

    Ceramic materials are commonly used to design multi-layer armour systems thanks to their favourable physical and mechanical properties. However, during an impact event, fragmentation of the ceramic plate inevitably occurs due to its inherent brittleness under tensile loading. Consequently, an accurate model of the fragmentation process is necessary in order to achieve an optimum design for a desired armour configuration. In this work, shockless spalling tests have been performed on two silicon carbide grades at strain rates ranging from 103 to 104 s−1 using a high-pulsed power generator. These spalling tests characterize the tensile strength strain rate sensitivity of each ceramic grade. The microstructural properties of the ceramics appear to play an important role on the strain rate sensitivity and on the dynamic tensile strength. Moreover, this experimental configuration allows for recovering damaged, but unbroken specimens, giving unique insight on the fragmentation process initiated in the ceramics. All the collected data have been compared with corresponding results of numerical simulations performed using the Denoual–Forquin–Hild anisotropic damage model. Good agreement is observed between numerical simulations and experimental data in terms of free surface velocity, size and location of the damaged zones along with crack density in these damaged zones. This article is part of the themed issue ‘Experimental testing and modelling of brittle materials at high strain rates’. PMID:27956504

  3. Strain rate sensitivity of the tensile strength of two silicon carbides: experimental evidence and micromechanical modelling

    Science.gov (United States)

    Zinszner, Jean-Luc; Erzar, Benjamin; Forquin, Pascal

    2017-01-01

    Ceramic materials are commonly used to design multi-layer armour systems thanks to their favourable physical and mechanical properties. However, during an impact event, fragmentation of the ceramic plate inevitably occurs due to its inherent brittleness under tensile loading. Consequently, an accurate model of the fragmentation process is necessary in order to achieve an optimum design for a desired armour configuration. In this work, shockless spalling tests have been performed on two silicon carbide grades at strain rates ranging from 103 to 104 s-1 using a high-pulsed power generator. These spalling tests characterize the tensile strength strain rate sensitivity of each ceramic grade. The microstructural properties of the ceramics appear to play an important role on the strain rate sensitivity and on the dynamic tensile strength. Moreover, this experimental configuration allows for recovering damaged, but unbroken specimens, giving unique insight on the fragmentation process initiated in the ceramics. All the collected data have been compared with corresponding results of numerical simulations performed using the Denoual-Forquin-Hild anisotropic damage model. Good agreement is observed between numerical simulations and experimental data in terms of free surface velocity, size and location of the damaged zones along with crack density in these damaged zones. This article is part of the themed issue 'Experimental testing and modelling of brittle materials at high strain rates'.

  4. Hypersonic Combustor Model Inlet CFD Simulations and Experimental Comparisons

    Science.gov (United States)

    Venkatapathy, E.; TokarcikPolsky, S.; Deiwert, G. S.; Edwards, Thomas A. (Technical Monitor)

    1995-01-01

    Numerous two-and three-dimensional computational simulations were performed for the inlet associated with the combustor model for the hypersonic propulsion experiment in the NASA Ames 16-Inch Shock Tunnel. The inlet was designed to produce a combustor-inlet flow that is nearly two-dimensional and of sufficient mass flow rate for large scale combustor testing. The three-dimensional simulations demonstrated that the inlet design met all the design objectives and that the inlet produced a very nearly two-dimensional combustor inflow profile. Numerous two-dimensional simulations were performed with various levels of approximations such as in the choice of chemical and physical models, as well as numerical approximations. Parametric studies were conducted to better understand and to characterize the inlet flow. Results from the two-and three-dimensional simulations were used to predict the mass flux entering the combustor and a mass flux correlation as a function of facility stagnation pressure was developed. Surface heat flux and pressure measurements were compared with the computed results and good agreement was found. The computational simulations helped determine the inlet low characteristics in the high enthalpy environment, the important parameters that affect the combustor-inlet flow, and the sensitivity of the inlet flow to various modeling assumptions.

  5. A constitutive model for the mechanical characterization of the plantar fascia.

    Science.gov (United States)

    Natali, Arturo N; Pavan, Piero G; Stecco, Carla

    2010-10-01

    A constitutive model is proposed to describe the mechanical behavior of the plantar fascia. The mechanical characterization of the plantar fascia regards the role in the foot biomechanics and it is involved in many alterations of its functional behavior, both of mechanical and nonmechanical origin. The structural conformation of the plantar fascia in its middle part is characterized by the presence of collagen fibers reinforcing the tissue along a preferential orientation, which is that supporting the major loading. According to this anatomical evidence, the tissue is described by developing an isotropic fiber-reinforced constitutive model and since the elastic response of the fascia is here considered, the constitutive model is based on the theory of hyperelasticity. The model is consistent with a kinematical description of large strains mechanical behavior, which is typical of soft tissues. A fitting procedure of the constitutive model is implemented making use of experimental curves taken from the literature and referring to specimens of human plantar fascia. A satisfactory fitting of the tensile behavior of the plantar fascia has been performed, showing that the model correctly interprets the mechanical behavior of the tissue in the light of comparison to experimental data at disposal. A critical analysis of the model with respect to the problem of the identification of the constitutive parameters is proposed as the basis for planning a future experimental investigation of mechanical behavior of the plantar fascia.

  6. Modelling concentration-analgesia relationships for morphine to evaluate experimental pain models

    DEFF Research Database (Denmark)

    Sverrisdóttir, Eva; Foster, David John Richard; Upton, Richard Neil

    2015-01-01

    The aim of this study was to develop population pharmacokinetic-pharmacodynamic models for morphine in experimental pain induced by skin heat and muscle pressure, and to evaluate the experimental pain models with regard to assessment of morphine pharmacodynamics. In a randomized, double......-blind, placebo-controlled, crossover study, 39 healthy volunteers received an oral dose of 30 mg morphine hydrochloride or placebo. Non-linear mixed effects modelling was used to describe the plasma concentrations of morphine and metabolites, and the analgesic effect of morphine on experimental pain in skin...... and muscle. Baseline pain metrics varied between individuals and occasions, and were described with interindividual and interoccasion variability. Placebo-response did not change with time. For both pain metrics, morphine effect was proportional to baseline pain and was described with a linear model...

  7. Experimental study and modelization of a propane storage tank depressurization

    International Nuclear Information System (INIS)

    Veneau, Tania

    1995-01-01

    The risks associated with the fast depressurization of propane storage tanks reveals the importance of the 'source term' determination. This term is directly linked, among others, to the characteristics of the jet developed downstream of the breach. The first aim of this work was to provide an original data bank concerning drop velocity and diameter distributions in a propane jet. For this purpose, a phase Doppler anemometer bas been implemented on an experimental set-up. Propane blowdowns have been performed with different breach sizes and several initial pressures in the storage tank. Drop diameter and velocity distributions have been investigated at different locations in the jet zone. These measurements exhibited the fragmentation and vaporisation trends in the jet. The second aim of this work concerned the 'source term'. lt required to study the coupling between the fluid behaviour inside the tank and the flow through the breach. This model took into account the phase exchange when flashing occurred in the tank. The flow at the breach was described with an homogeneous relaxation model. This coupled modelization has been successfully and exhaustively validated. lt originality lies on the application to propane flows. (author) [fr

  8. Computational reverse shoulder prosthesis model: Experimental data and verification.

    Science.gov (United States)

    Martins, A; Quental, C; Folgado, J; Ambrósio, J; Monteiro, J; Sarmento, M

    2015-09-18

    The reverse shoulder prosthesis aims to restore the stability and function of pathological shoulders, but the biomechanical aspects of the geometrical changes induced by the implant are yet to be fully understood. Considering a large-scale musculoskeletal model of the upper limb, the aim of this study is to evaluate how the Delta reverse shoulder prosthesis influences the biomechanical behavior of the shoulder joint. In this study, the kinematic data of an unloaded abduction in the frontal plane and an unloaded forward flexion in the sagittal plane were experimentally acquired through video-imaging for a control group, composed of 10 healthy shoulders, and a reverse shoulder group, composed of 3 reverse shoulders. Synchronously, the EMG data of 7 superficial muscles were also collected. The muscle force sharing problem was solved through the minimization of the metabolic energy consumption. The evaluation of the shoulder kinematics shows an increase in the lateral rotation of the scapula in the reverse shoulder group, and an increase in the contribution of the scapulothoracic joint to the shoulder joint. Regarding the muscle force sharing problem, the musculoskeletal model estimates an increased activity of the deltoid, teres minor, clavicular fibers of the pectoralis major, and coracobrachialis muscles in the reverse shoulder group. The comparison between the muscle forces predicted and the EMG data acquired revealed a good correlation, which provides further confidence in the model. Overall, the shoulder joint reaction force was lower in the reverse shoulder group than in the control group. Copyright © 2015 Elsevier Ltd. All rights reserved.

  9. Models of Investor Forecasting Behavior — Experimental Evidence

    Directory of Open Access Journals (Sweden)

    Federico Bonetto

    2017-12-01

    Full Text Available Different forecasting behaviors affect investors’ trading decisions and lead to qualitatively different asset price trajectories. It has been shown in the literature that the weights that investors place on observed asset price changes when forecasting future price changes, and the nature of their confidence when price changes are forecast, determine whether price bubbles, price crashes, and unpredictable price cycles occur. In this paper, we report the results of behavioral experiments involving multiple investors who participated in a market for a virtual asset. Our goal is to study investors’ forecast formation. We conducted three experimental sessions with different participants in each session. We fit different models of forecast formation to the observed data. There is strong evidence that the investors forecast future prices by extrapolating past price changes, even when they know the fundamental value of the asset exactly and the extrapolated forecasts differ significantly from the fundamental value. The rational expectations hypothesis seems inconsistent with the observed forecasts. The forecasting models of all participants that best fit the observed forecasting data were of the type that cause price bubbles and cycles in dynamical systems models, and price bubbles and cycles ended up occurring in all three sessions.

  10. Optimization of Experimental Model Parameter Identification for Energy Storage Systems

    Directory of Open Access Journals (Sweden)

    Rosario Morello

    2013-09-01

    Full Text Available The smart grid approach is envisioned to take advantage of all available modern technologies in transforming the current power system to provide benefits to all stakeholders in the fields of efficient energy utilisation and of wide integration of renewable sources. Energy storage systems could help to solve some issues that stem from renewable energy usage in terms of stabilizing the intermittent energy production, power quality and power peak mitigation. With the integration of energy storage systems into the smart grids, their accurate modeling becomes a necessity, in order to gain robust real-time control on the network, in terms of stability and energy supply forecasting. In this framework, this paper proposes a procedure to identify the values of the battery model parameters in order to best fit experimental data and integrate it, along with models of energy sources and electrical loads, in a complete framework which represents a real time smart grid management system. The proposed method is based on a hybrid optimisation technique, which makes combined use of a stochastic and a deterministic algorithm, with low computational burden and can therefore be repeated over time in order to account for parameter variations due to the battery’s age and usage.

  11. Integration of THM-experimental work and modelling

    International Nuclear Information System (INIS)

    Pintado, Xavier; Autio, Jorma; Koskinen, Kari

    2010-01-01

    Document available in extended abstract form only. Long-term safety of the bentonite buffer relies heavily on appropriate saturation of bentonite buffer resulting evidently on adequate swelling pressure low hydraulic conductivity. After transient period after installation of buffer components the buffer swelling pressure is to remain sufficiently high regardless of e.g. the conditions during the early evolution promoting hydrothermal alteration. For these reasons it is of central importance to characterise different 'underlying saturation flow regimes', USFRs, and the related time dependent fluxes in various parts of buffer in then currently prevailing conditions. The THM processes govern the behaviour from transient to fully saturated state and occur during long periods of time from tens of years up to hundreds or even more. Therefore it is important to be able to understand the underlying processes sufficiently and to develop proper modelling techniques. This can be carried out only by integrating testing and modelling. THM-modelling has also important role in design development phase when different engineering techniques e.g. for wetting of buffer are evaluated. This paper presents the integration of THM-experimental work and modelling carried out in Finland and elsewhere for the development of the buffer designs. The primary objective of this work is to provide experimental and modelling data for assessing the behaviour of bentonite buffer during saturation with respect to fulfilling the performance targets. The development of numerical methods allows to simulate the different processes which take place in materials and to understand them better. In laboratory testing, the numerical methods allow us to simulate the tests and to choose the best geometry and boundary conditions and to verify the experimental designs. The clay barrier behaviour is complex because there are some phenomena coupled: heat flow, water flow in vapour and liquid phases and

  12. Cracking in autoclaved aerated concrete: Experimental investigation and XFEM modeling

    International Nuclear Information System (INIS)

    Ferretti, D.; Michelini, E.; Rosati, G.

    2015-01-01

    The paper aims to investigate and model cracking development in beams and deep-beams made of autoclaved aerated concrete (AAC). Fracture mechanics of AAC has been first studied by performing three-point bending tests on beams, similar to those commonly used for ordinary concrete elements. In some of these tests, crack growth has been also monitored by using ESPI laser technique. In this way, it has been possible to calibrate the main parameters of a proper cohesive law by means of extended finite element inverse analysis. Subsequently, cracking tests have been also performed on deep-beams, whose behavior is more representative of full scale walls. To validate the proposed cohesive law, deep-beam experimental behavior has been finally simulated through XFEM

  13. Cracking in autoclaved aerated concrete: Experimental investigation and XFEM modeling

    Energy Technology Data Exchange (ETDEWEB)

    Ferretti, D., E-mail: daniele.ferretti@unipr.it [Department of Civil, Environmental, Land Management Engineering and Architecture, University of Parma, P.co Area delle Scienze 181/A, 43124 Parma (Italy); Michelini, E. [Department of Civil, Environmental, Land Management Engineering and Architecture, University of Parma, P.co Area delle Scienze 181/A, 43124 Parma (Italy); Rosati, G. [Department of Civil and Environmental Engineering, Politecnico di Milano, Piazza L. Da Vinci 32, 20133 Milano (Italy)

    2015-01-15

    The paper aims to investigate and model cracking development in beams and deep-beams made of autoclaved aerated concrete (AAC). Fracture mechanics of AAC has been first studied by performing three-point bending tests on beams, similar to those commonly used for ordinary concrete elements. In some of these tests, crack growth has been also monitored by using ESPI laser technique. In this way, it has been possible to calibrate the main parameters of a proper cohesive law by means of extended finite element inverse analysis. Subsequently, cracking tests have been also performed on deep-beams, whose behavior is more representative of full scale walls. To validate the proposed cohesive law, deep-beam experimental behavior has been finally simulated through XFEM.

  14. Practical application of stereological methods in experimental kidney animal models.

    Science.gov (United States)

    Fernández García, María Teresa; Núñez Martínez, Paula; García de la Fuente, Vanessa; Sánchez Pitiot, Marta; Muñiz Salgueiro, María Del Carmen; Perillán Méndez, Carmen; Argüelles Luis, Juan; Astudillo González, Aurora

    The kidneys are vital organs responsible for excretion, fluid and electrolyte balance and hormone production. The nephrons are the kidney's functional and structural units. The number, size and distribution of the nephron components contain relevant information on renal function. Stereology is a branch of morphometry that applies mathematical principles to obtain three-dimensional information from serial, parallel and equidistant two-dimensional microscopic sections. Because of the complexity of stereological studies and the lack of scientific literature on the subject, the aim of this paper is to clearly explain, through animal models, the basic concepts of stereology and how to calculate the main kidney stereological parameters that can be applied in future experimental studies. Copyright © 2016 Sociedad Española de Nefrología. Published by Elsevier España, S.L.U. All rights reserved.

  15. Hadronic models and experimental data for the neutrino beam production

    CERN Document Server

    Collazuol, G; Guglielmi, A M; Sala, P R

    2000-01-01

    The predictions of meson production by 450 GeV/c protons on Be using the Monte Carlo FLUKA standalone and GEANT-FLUKA and GEANT-GHEISHA in GEANT are compared with available experimental measurements. The comparison enlightens the improvements of the hadronic generator models of the present standalone code FLUKA with respect to the 1992 version which is embedded into GEANT-FLUKA. Worse results were obtained with the GHEISHA package. A complete simulation of the SPS neutrino beam line at CERN showed significant variations in the intensity and composition of the neutrino beam when FLUKA standalone instead of the GEANT-FLUKA package is used to simulate particle production in the Be target.

  16. Hadronic models and experimental data for the neutrino beam production

    International Nuclear Information System (INIS)

    Collazuol, G.; Ferrari, A.; Guglielmi, A.; Sala, P.R.

    2000-01-01

    The predictions of meson production by 450 GeV/c protons on Be using the Monte Carlo FLUKA standalone and GEANT-FLUKA and GEANT-GHEISHA in GEANT are compared with available experimental measurements. The comparison enlightens the improvements of the hadronic generator models of the present standalone code FLUKA with respect to the 1992 version which is embedded into GEANT-FLUKA. Worse results were obtained with the GHEISHA package. A complete simulation of the SPS neutrino beam line at CERN showed significant variations in the intensity and composition of the neutrino beam when FLUKA standalone instead of the GEANT-FLUKA package is used to simulate particle production in the Be target

  17. Stratification of bubbly horizontal flows: modeling and experimental validation

    International Nuclear Information System (INIS)

    Bottin, M.

    2010-01-01

    Hot films and optical probes enabled the acquisition of measurements in bubbly flows at 5, 20 and 40 diameters from the inlet of the vein on the METERO facility which test section is a horizontal circular pipe of 100 mm inner diameter. The distribution of the different phases, the existence of coalescence and sedimentation mechanisms, the influence of the liquid and gas flow rates, the radial and axial evolutions are analyzed thanks to fast camera videos and numerous and varied experimental results (void fraction, bubbles sizes, interfacial area, mean and fluctuating velocities and turbulent kinetic energy of the liquid phase). Some models, based on the idea that the flow reaches an equilibrium state sufficiently far from the inlet of the pipe, were developed to simulate mean interfacial area and turbulent kinetic energy transports in bubbly flows. (author)

  18. Experimental and numerical investigation of a simplified exhaust model

    Directory of Open Access Journals (Sweden)

    Balázs Vehovszky

    2016-10-01

    Full Text Available A simplified experimental equipment was built to investigate heat radiation and free convection around hot exhaust pipe. Temperatures were measured on the surface of the pipe as like as on heat insulating and -reflecting aluminum shield. Special care was taken to the temperature measuring method: result proved that inappropriate fixing of measuring thermocouples lead to an error of up to 30 % in the temperature-increase values. A detailed 1D numerical model was set up and parametrized so as to the calculation results can be fitted to measured temperature values. In this way thermal properties of the surfaces – as emissivities, absorption coefficients and convective heat transfer coefficients – were determined for temperature sweeps and stationary state cases. The used methods are to be further improved for real automotive parts and higher temperatures.

  19. Gastroprotective effect of Senecio candicans DC on experimental ulcer models.

    Science.gov (United States)

    Hariprasath, Lakshmanan; Raman, Jegadeesh; Nanjian, Raaman

    2012-03-06

    Senecio candicans DC (Asteraceae) is used as a remedy for gastric ulcer and stomach pain in the Nilgiris district, Tamil Nadu for which no scientific evidence exists. The present study was performed to evaluate the gastroprotective effects and acute oral toxicity of aqueous leaf extract of Senecio candicans (AESC) in experimental models. The antiulcerogenic activity of AESC was performed in two different ulcer models viz., pylorus-ligated model and ethanol-induced model using Wistar albino rats. Acute toxicity study was also performed to get information on the admissible dose for treatment of ulcer. Preliminary phytochemical screening of AESC was performed to find the active principles present, which are thus responsible for the antiulcerogenic activity. DPPH assay was performed to confirm the antioxidant activity of AESC. The acute toxicity study did not show any mortality up to 2500mg/kg b.w. of AESC. Both the ulcer models showed gastroprotective effect comparable to that of the standard Omeprazole. The results of antioxidant enzymes, histopathology sections, ATPase and mucus content of gastric secretion showed that several mechanisms are involved in the gastroprotective effect. The preliminary phytochemical screening revealed the presence of alkaloids, flavonoids and steroids in AESC. The DPPH assay confirmed the antioxidant activity of AESC. The traditional consumption of AESC for the treatment of gastric ulcer is thus true, the antioxidant constituents present in the extract plays a major role in the gastroprotective activity, but since Senecio species are known for the presence of pyrrolizidine alkaloids, a detailed study in future is required to describe the safe dose for a prolonged period. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

  20. Characterization uncertainty and its effects on models and performance

    International Nuclear Information System (INIS)

    Rautman, C.A.; Treadway, A.H.

    1991-01-01

    Geostatistical simulation is being used to develop multiple geologic models of rock properties at the proposed Yucca Mountain repository site. Because each replicate model contains the same known information, and is thus essentially indistinguishable statistically from others, the differences between models may be thought of as representing the uncertainty in the site description. The variability among performance measures, such as ground water travel time, calculated using these replicate models therefore quantifies the uncertainty in performance that arises from uncertainty in site characterization

  1. Variability aware compact model characterization for statistical circuit design optimization

    Science.gov (United States)

    Qiao, Ying; Qian, Kun; Spanos, Costas J.

    2012-03-01

    Variability modeling at the compact transistor model level can enable statistically optimized designs in view of limitations imposed by the fabrication technology. In this work we propose an efficient variabilityaware compact model characterization methodology based on the linear propagation of variance. Hierarchical spatial variability patterns of selected compact model parameters are directly calculated from transistor array test structures. This methodology has been implemented and tested using transistor I-V measurements and the EKV-EPFL compact model. Calculation results compare well to full-wafer direct model parameter extractions. Further studies are done on the proper selection of both compact model parameters and electrical measurement metrics used in the method.

  2. Characterization of materials for a reactive transport model validation experiment: Interim report on the caisson experiment. Yucca Mountain Site Characterization Project

    International Nuclear Information System (INIS)

    Siegel, M.D.; Cheng, W.C.; Ward, D.B.; Bryan, C.R.

    1995-08-01

    Models used in performance assessment and site characterization activities related to nuclear waste disposal rely on simplified representations of solute/rock interactions, hydrologic flow field and the material properties of the rock layers surrounding the repository. A crucial element in the design of these models is the validity of these simplifying assumptions. An intermediate-scale experiment is being carried out at the Experimental Engineered Test Facility at Los Alamos Laboratory by the Los Alamos and Sandia National Laboratories to develop a strategy to validate key geochemical and hydrological assumptions in performance assessment models used by the Yucca Mountain Site Characterization Project

  3. Characterization of materials for a reactive transport model validation experiment: Interim report on the caisson experiment. Yucca Mountain Site Characterization Project

    Energy Technology Data Exchange (ETDEWEB)

    Siegel, M.D.; Cheng, W.C. [Sandia National Labs., Albuquerque, NM (United States); Ward, D.B.; Bryan, C.R. [Univ. of New Mexico, Albuquerque, NM (United States). Dept. of Earth and Planetary Sciences

    1995-08-01

    Models used in performance assessment and site characterization activities related to nuclear waste disposal rely on simplified representations of solute/rock interactions, hydrologic flow field and the material properties of the rock layers surrounding the repository. A crucial element in the design of these models is the validity of these simplifying assumptions. An intermediate-scale experiment is being carried out at the Experimental Engineered Test Facility at Los Alamos Laboratory by the Los Alamos and Sandia National Laboratories to develop a strategy to validate key geochemical and hydrological assumptions in performance assessment models used by the Yucca Mountain Site Characterization Project.

  4. An experimental model of mycobacterial infection under corneal flaps

    Directory of Open Access Journals (Sweden)

    C.B.D. Adan

    2004-07-01

    Full Text Available In order to develop a new experimental animal model of infection with Mycobacterium chelonae in keratomileusis, we conducted a double-blind prospective study on 24 adult male New Zealand rabbits. One eye of each rabbit was submitted to automatic lamellar keratotomy with the automatic corneal shaper under general anesthesia. Eyes were immunosuppressed by a single local injection of methyl prednisolone. Twelve animals were inoculated into the keratomileusis interface with 1 µl of 10(6 heat-inactivated bacteria (heat-inactivated inoculum controls and 12 with 1 µl of 10(6 live bacteria. Trimethoprim drops (0.1%, w/v were used as prophylaxis for the surgical procedure every 4 h (50 µl, qid. Animals were examined by 2 observers under a slit lamp on the 1st, 3rd, 5th, 7th, 11th, 16th, and 23rd postoperative days. Slit lamp photographs were taken to document clinical signs. Animals were sacrificed when corneal disease was detected and corneal samples were taken for microbiological analysis. Eleven of 12 experimental rabbits developed corneal disease, and M. chelonae could be isolated from nine rabbits. Eleven of the 12 controls receiving a heat-inactivated inoculum did not develop corneal disease. M. chelonae was not isolated from any of the control rabbits receiving a heat-inactivated inoculum, or from the healthy cornea of control rabbits. Corneal infection by M. chelonae was successfully induced in rabbits submitted to keratomileusis. To our knowledge, this is the first animal model of M. chelonae infection following corneal flaps for refractive surgery to be described in the literature and can be used for the analysis of therapeutic responses.

  5. Calcium Intervention Ameliorates Experimental Model of Multiple Sclerosis

    Directory of Open Access Journals (Sweden)

    Dariush Haghmorad

    2014-05-01

    Full Text Available Objective: Multiple sclerosis (MS is the most common inflammatory disease of the CNS. Experimental autoimmune encephalomyelitis (EAE is a widely used model for MS. In the present research, our aim was to test the therapeutic efficacy of Calcium (Ca in an experimental model of MS. Methods: In this study the experiment was done on C57BL/6 mice. EAE was induced using 200 μg of the MOG35-55 peptide emulsified in CFA and injected subcutaneously on day 0 over two flank areas. In addition, 250 ng of pertussis toxin was injected on days 0 and 2. In the treatment group, 30 mg/kg Ca was administered intraperitoneally four times at regular 48 hour intervals. The mice were sacrificed 21 days after EAE induction and blood samples were taken from their hearts. The brains of mice were removed for histological analysis and their isolated splenocytes were cultured. Results: Our results showed that treatment with Ca caused a significant reduction in the severity of the EAE. Histological analysis indicated that there was no plaque in brain sections of Ca treated group of mice whereas 4 ± 1 plaques were detected in brain sections of controls. The density of mononuclear infiltration in the CNS of Ca treated mice was lower than in controls. The serum level of Nitric Oxide in the treatment group was lower than in the control group but was not significant. Moreover, the levels of IFN-γ in cell culture supernatant of splenocytes in treated mice were significantly lower than in the control group. Conclusion: The data indicates that Ca intervention can effectively attenuate EAE progression.

  6. Experimental Contribution to High Precision Characterization of Magnetic Forces in Active Magnetic Bearings

    DEFF Research Database (Denmark)

    Kjølhede, Klaus; Santos, Ilmar

    2006-01-01

    Parameter identification procedures and model validation are major steps towards intelligent machines supported by active magnetic bearings (AMB). The ability of measuring the electromagnetic bearing forces, or deriving them from measuring the magnetic flux, strongly contributes to the model...... validation and leads to novel approaches in identifying crucial rotor parameters. This is the main focus of this paper, where an intelligent AMB is being developed with the aim of aiding the accurate identification of damping and stiffness coefficients of active lubricated journal bearings. The main...... of the magnetic forces is conducted using different experimental tests: (a) by using hall sensors mounted directly on the poles (precise measurements of the magnetic flux) and by an auxiliary system, composed of strain gages and flexible beams attached to the rotor, (b) by measuring the input current and bearing...

  7. Comparison of Experimental and Numerical Two-Phase Flows in a Porous Micro-Model

    Directory of Open Access Journals (Sweden)

    Dustin Crandall

    2009-12-01

    Full Text Available Characterizing two-phase flow in porous media is important to provide estimates of sweep efficiency in enhanced oil recovery and storage estimates in potential geological CO2 sequestration repositories. To further the current understanding of two-phase flow in porous media a micro-model of interconnected channels was designed and fabricated using stereolithography to experimentally study gas-liquid flows. This flowcell was created with a wide variability of throat dimensions to represent naturally occurring porous media. Low flow rate experiments of immiscible two-phase drainage were performed within this cell. Additionally, a computational model for analyzing two-phase flows in the same flowcell was developed and used to simulate conditions not possible with our laboratory settings. The computational model was first tested for the identical conditions used in the experimental studies, and was shown to be in good agreement with the experimentally determined fractal dimension of the invading gas structure, time until breakthrough, and fluid saturation. The numerical model was then used to study two-phase air-water flows in flowcells with the same geometry and different gas-liquid-solid contact angles. The percent saturation of air and the motion of the fluids through the cell were found to vary with changes in these parameters. Finally, to simulate flows expected during geologic carbon sequestration, the fluid properties and interface conditions were set to model the flow of CO2 into a brine-saturated porous medium at representative subsurface conditions. The CO2 flows were shown to have larger gas saturations than the previous air into water studies. Thus the accuracy of the computational model was supported by the flowcell experiments, and the computational model extended the laboratory results to conditions not possible with the apparatus used in the experiments.

  8. An innovative magnetorheological damper for automotive suspension: from design to experimental characterization

    Science.gov (United States)

    Sassi, Sadok; Cherif, Khaled; Mezghani, Lotfi; Thomas, Marc; Kotrane, Asma

    2005-08-01

    The development of a powerful new magnetorheological fluid (MRF), together with recent progress in the understanding of the behavior of such fluids, has convinced researchers and engineers that MRF dampers are among the most promising devices for semi-active automotive suspension vibration control, because of their large force capacity and their inherent ability to provide a simple, fast and robust interface between electronic controls and mechanical components. In this paper, theoretical and experimental studies are performed for the design, development and testing of a completely new MRF damper model that can be used for the semi-active control of automotive suspensions. The MR damper technology presented in this paper is based on a completely new approach where, in contrast to in the conventional solutions where the coil axis is usually superposed on the damper axis and where the inner cylindrical housing is part of the magnetic circuit, the coils are wound in a direction perpendicular to the damper axis. The paper investigates approaches to optimizing the dynamic response and provides experimental verification. Both experimental and theoretical results have shown that, if this particular model is filled with an 'MRF 336AG' MR fluid, it can provide large controllable damping forces that require only a small amount of energy. For a magnetizing system with four coils, the damping coefficient could be increased by up to three times for an excitation current of only 2 A. Such current could be reduced to less than 1 A if the magnetizing system used eight small cores. In this case, the magnetic field will be more powerful and more regularly distributed. In the presence of harmonic excitation, such a design will allow the optimum compromise between comfort and stability to be reached over different intervals of the excitation frequencies.

  9. Modelling of PEM Fuel Cell Performance: Steady-State and Dynamic Experimental Validation

    Directory of Open Access Journals (Sweden)

    Idoia San Martín

    2014-02-01

    Full Text Available This paper reports on the modelling of a commercial 1.2 kW proton exchange membrane fuel cell (PEMFC, based on interrelated electrical and thermal models. The electrical model proposed is based on the integration of the thermodynamic and electrochemical phenomena taking place in the FC whilst the thermal model is established from the FC thermal energy balance. The combination of both models makes it possible to predict the FC voltage, based on the current demanded and the ambient temperature. Furthermore, an experimental characterization is conducted and the parameters for the models associated with the FC electrical and thermal performance are obtained. The models are implemented in Matlab Simulink and validated in a number of operating environments, for steady-state and dynamic modes alike. In turn, the FC models are validated in an actual microgrid operating environment, through the series connection of 4 PEMFC. The simulations of the models precisely and accurately reproduce the FC electrical and thermal performance.

  10. Intermediate Experimental Vehicle, ESA Program IXV ATDB Tool and Aerothermodynamic Characterization

    Science.gov (United States)

    Mareschi, Vincenzo; Ferrarella, Daniela; Zaccagnino, Elio; Tribot, Jean-Pierre; Vallee, Jean-Jacques; Haya-Ramos, Rodrigo; Rufolo, Giuseppe; Mancuso, Salvatore

    2011-05-01

    In the complex domain of the space technologies and among the different applications available in Europe, a great interest has been placed since several years in the development of re-entry technologies. Among the different achievements obtained in that field it is to be recalled the experience of the Atmospheric Re-entry Vehicle flight in 1998 and a certain number of important investments per-formed at Agency and national levels like Hermes, MSTP, Festip, X-38, FLPP, TRP, GSTP, HSTS, AREV, Pre-X. IXV (Intermediate eXperimental V ehicle) builds on these past experiences and studies and it is conceived to be the next technological step forward with respect to ARD With respect to previous European ballistic or quasi- ballistic demonstrators, IXV will have an increased in- flight manoeuvrability and the planned mission will allow verifying the performances of the required technologies against a wider re-entry corridor. This will imply from the pure technological aspect to increase the level of engagement on critical technologies and disciplines like aerodynamics/aerothermodynamics, guidance, navigation, control, thermal protection materials and in flight measurements. In order to support the TPS design and the other sub- systems, an AeroThermodynamicDataBase Tool has been developed by Dassault Aviation and integrated by Thales Alenia Space with the Functional Engineering Simulator (used for GNC performances evaluation) in order to characterize the aerothermodynamic behaviour of the vehicle. This paper will describe: - The methodology used to develop the ATDB tool, based on the processing of CFD computations and WTT campaigns results. - The utilization of the ATDB tool, by means of its integration into the System process. - The methodology used for the aerothermal characterization of IXV.

  11. Experimental investigation and characterization of micro resistance welding with an electro-thermal actuator

    International Nuclear Information System (INIS)

    Chang, Chun-Wei; Yeh, Cheng-Chi; Hsu Wensyang

    2009-01-01

    Resistance welding is a common scheme of assembly on the macro scale by pressing together two workpieces with current passing through them to generate joule heating at the contact region due to high contact resistance. However, micro assembly by resistance welding is seldom reported. Here, resistance welding with an electro-thermal microactuator to assemble micro Ni structures is experimentally investigated and characterized. The bent-beam electro-thermal microactuator is designed to provide the necessary displacements and pressing forces. The two-mask metal-based surface micromachining process is adopted to fabricate the micro Ni structures. The calibrated initial contact resistance is shown to decrease with increasing contact pressure. Furthermore, stronger welding strength is achieved at a smaller initial contact resistance, which indicates that a larger clamping force would enhance the welding strength as large as 3.09 MPa (74.4 µN) at a contact resistance of 2.7 Ω here. The input welding energy is also found to be a critical factor. In our tests, when welding energy is below the threshold limit of 0.05 J, the welding trials all fail. For the energy between 0.05 J and 1 J, there is a transition from a lower yield of 33.3% to a higher yield of 58.3%. At high welding energy, between 1 and 10 J, 100% yield is achieved. With the demonstration and characterization of micro resistance welding by the electro-thermal microactuator, the scheme proposed here would be helpful in the automation of micro assembly

  12. Computational and experimental characterization of a liquid jet plunging into a quiescent pool at shallow inclination

    International Nuclear Information System (INIS)

    Deshpande, Suraj S.; Trujillo, Mario F.; Wu Xiongjun; Chahine, Georges

    2012-01-01

    Highlights: ► Jet impingement at shallow angles results in periodic cavity formation. ► Velocity profile affected both by buoyancy and splashing in the near field. ► Momentum diffusion leads to a velocity maximum at the gas–liquid interface for the far field. - Abstract: A circular water jet (Re = 1.6 × 10 5 ; We = 8.8 × 10 3 ) plunging at shallow angles (θ ≈ 12.5°) into a quiescent pool is investigated computationally and experimentally. A surprising finding from the work is that cavities, of the order of jet diameter, are formed periodically in the impact location, even though the impinging flow is smooth and completely devoid of such a periodicity. Computational prediction of these frequencies was compared with experimental findings, yielding excellent agreement. The region in the vicinity of the impact is characterized by strong churning due to splashing and formation of air cavities. Measured velocity profiles indicate a concentration of momentum beneath the free surface slightly beyond the impact location (X/D j ≈ 14), with a subsequent shift towards the free surface further downstream of this point (X/D j ≈ 30). This shift is due primarily to the action of buoyancy on the cavity/bubble population. Comparisons of the mean velocity profile between simulations and experiments are performed, yielding good agreement, with the exception of the relatively small churning flow region. Further downstream (X/D j ≳ 40), the flow develops mostly due to diffusion and the location of peak velocity coincides with the free surface. In this region, the free surface acts as an adiabatic boundary and restricts momentum diffusion, causing the peak velocity to occur at the free surface.

  13. LLUSTRATION OF AMINO ACIDS REACTIONS AND PROTEINS CHARACTERIZATION FOR EXPERIMENTAL BIOCHEMISTRY CLASSES

    Directory of Open Access Journals (Sweden)

    I. Parreira

    2008-05-01

    Full Text Available New teaching methodologies have been developed to facilitate the learning of biochemistry concepts. A new  approach to Biochemistry  teaching  has become more frequent,  one that does not  require reagents but use photos, videos, softwares etc. Experimental Biochemistry classes, i.e. covering characterization of amino acids and proteins,  might be more productive with the use of complementary didactic material.  Furthermore,  if experiments cannot be implemented, classes may  be well illustrated with complementary didactic material covering from the simplest to the most  complex experiments.  In order to  aid Biochemistry classes without practical experiments, some tests and reactions were documented in our laboratory through digital photos, for  instance: (1 the biuret reaction wherein the blue reagent turns violet in the presence of proteins and changes to pink when combined with short-chain polypeptides; (2 the ninhydrin test used in amino acid analysis of proteins: most of the amino acids are hydrolyzed and react with ninhydrin; when reacting with these free amines, a deep blue or purple color appears; (3 methods for detecting proteins wherein spectrophotometry is used, that deals with the relationship between absorbance, concentration and path length, which constitute the Beer-Lambert Law. A didactic material constituted by texts, schemes and illustrated by photos has been created for each class topic. This material can be used either as a teacher script or in a presentation form to illustrate classes without experimental activities. Financial Support: Pro-Reitoria Graduação-USP, CNPq.

  14. Experimental procedure for the characterization of cyclic behavior from very thin plate specimens

    International Nuclear Information System (INIS)

    Maury, A.; Moulin, D.

    1983-01-01

    Many investigators, including those involved in the INTERNATIONAL BENCHMARK PROJECT ON SIMPLIFIED METHODS FOR ELEVATED TEMPERATURE DESIGN AND ANALYSIS - PROBLEM II, have tried to reproduce experimentally observed behavior by inelastic calculations. Unfortunately, the material characteristics used in the computer code were established from monotonic tensile tests performed with specimens extracted from the plate product itself (1.45 mm thick) employed to construct the ratchetting specimen. It now appears that the cyclic behavior of the material is much more relevant to the phenomenon observed. Hence the need to make this kind of characterization. Nevertheless, the practical problem is to produce cyclic stresses, i.e. tensile and compressive stresses, with very thin specimens. The main difficulty is to prevent the buckling effect. A new special device set up for this particular purpose is described here. The solution adopted was to create uniformly distributed alternative pure bending stresses in the thin plate specimen. Bending moments were produced by two end-grips fixed to the specimen, and these grips were mounted on a conventional test-machine which was displacement-controlled. To reduce tensile and compressive membrane stresses inside the specimen, the grips had two parallel axles of rotation. The forces produced by the machine and the displacements of a number of points of the specimen were continuously recorded during the test, so that cyclically stabilized, bending moments could be evaluated easily for each curvature variation imposed. The very first cyclic experimental data obtained, at room temperature, for the material of the sodium test specimen, a 316 type stainless steel, are presented. It may be noted that the simple specimens were very easy to prepare and hence inexpensive. (orig.)

  15. Site characterization and validation - Head variations during the entire experimental period

    International Nuclear Information System (INIS)

    Haigh, D.; Brightman, M.; Black, J.; Parry, S.

    1992-01-01

    The site characterization and validation project lasted for five years from 1986 to 1991. It consisted of a number of experiments within the region known as the SCV site. During this period of experimentation a monitoring system was established within the mine for the purpose of measuring the variation of head at a number of locations within and around the site. The system installed was based around a set of equipment known as a Piezomac TM system. In this system there is one central pressure transducer and each borehole interval is connected to it in turn. It can measure up to 55 separate points during each measurement 'cycle'. Monitoring points were either complete boreholes or sections of boreholes isolated by packers. In order to produce reasonable file size, data sets were screened. The results show that the SCV site was always responding to some form of hydrogeological disturbance. Many key tests were performed against changing background trends. This was particularly so of the simulated drift experiment and the large scale crosshole tests. However, some estimates of long term equilibrium heads before and after excavation of the validation drift have been made. Contoured plots of heads before and after show significant reduction of steady state heads as a result of drift excavation. Furthermore contouring the estimated long term drawdowns responding to the simulated drift experiment shows the specific influence of the H zone and the A/B zone. Overall the results of the monitoring show that the mine was a very active hydrogeological environment during the experimentation. Additionally it was often very difficult to clearly identify the causes of such disturbances. (au)

  16. Characterization of a pneumococcal meningitis mouse model

    Directory of Open Access Journals (Sweden)

    Mook-Kanamori Barry

    2012-03-01

    Full Text Available Abstract Background S. pneumoniae is the most common causative agent of meningitis, and is associated with high morbidity and mortality. We aimed to develop an integrated and representative pneumococcal meningitis mouse model resembling the human situation. Methods Adult mice (C57BL/6 were inoculated in the cisterna magna with increasing doses of S. pneumoniae serotype 3 colony forming units (CFU; n = 24, 104, 105, 106 and 107 CFU and survival studies were performed. Cerebrospinal fluid (CSF, brain, blood, spleen, and lungs were collected. Subsequently, mice were inoculated with 104 CFU S. pneumoniae serotype 3 and sacrificed at 6 (n = 6 and 30 hours (n = 6. Outcome parameters were bacterial outgrowth, clinical score, and cytokine and chemokine levels (using Luminex® in CSF, blood and brain. Meningeal inflammation, neutrophil infiltration, parenchymal and subarachnoidal hemorrhages, microglial activation and hippocampal apoptosis were assessed in histopathological studies. Results Lower doses of bacteria delayed onset of illness and time of death (median survival CFU 104, 56 hrs; 105, 38 hrs, 106, 28 hrs. 107, 24 hrs. Bacterial titers in brain and CSF were similar in all mice at the end-stage of disease independent of inoculation dose, though bacterial outgrowth in the systemic compartment was less at lower inoculation doses. At 30 hours after inoculation with 104 CFU of S. pneumoniae, blood levels of KC, IL6, MIP-2 and IFN- γ were elevated, as were brain homogenate levels of KC, MIP-2, IL-6, IL-1β and RANTES. Brain histology uniformly showed meningeal inflammation at 6 hours, and, neutrophil infiltration, microglial activation, and hippocampal apoptosis at 30 hours. Parenchymal and subarachnoidal and cortical hemorrhages were seen in 5 of 6 and 3 of 6 mice at 6 and 30 hours, respectively. Conclusion We have developed and validated a murine model of pneumococcal meningitis.

  17. Characterizing new compositions of [001]C relaxor ferroelectric single crystals using a work-energy model

    Science.gov (United States)

    Gallagher, John A.

    2016-04-01

    The desired operating range of ferroelectric materials with compositions near the morphotropic phase boundary is limited by field induced phase transformations. In [001]C cut and poled relaxor ferroelectric single crystals the mechanically driven ferroelectric rhombohedral to ferroelectric orthorhombic phase transformation is hindered by antagonistic electrical loading. Instability around the phase transformation makes the current experimental technique for characterization of the large field behavior very time consuming. Characterization requires specialized equipment and involves an extensive set of measurements under combined electrical, mechanical, and thermal loads. In this work a mechanism-based model is combined with a more limited set of experiments to obtain the same results. The model utilizes a work-energy criterion that calculates the mechanical work required to induce the transformation and the required electrical work that is removed to reverse the transformation. This is done by defining energy barriers to the transformation. The results of the combined experiment and modeling approach are compared to the fully experimental approach and error is discussed. The model shows excellent predictive capability and is used to substantially reduce the total number of experiments required for characterization. This decreases the time and resources required for characterization of new compositions.

  18. Experimental identification and mathematical modeling of viscoplastic material behavior

    Science.gov (United States)

    Haupt, P.; Lion, A.

    1995-03-01

    Uniaxial torsion and biaxial torsion-tension experiments on thin-walled tubes were carried out to investigate the viscoplastic behavior of stainless steel XCrNi18.9. A series of monotonic tests under strain and stress control shows nonlinear rate dependence and suggests the existence of equilibrium states, which are asymptotically approached during relaxation and creep processes. Strain controlled cyclic experiments display various hardening and softening phenomena that depend on strain amplitude and mean strain. All experiments indicate that the equilibrium states within the material depend on the history of the input process, whereas the history-dependence of the relaxation and creep behavior appears less significant. From the experiments the design of a constitutive model of viscoplasticity is motivated: The basic assumption is a decomposition of the total stress into an equilibrium stress and a non-equilibrium overstress: At constant strain, the overstress relaxes to zero, where the relaxation time depends on the overstress in order to account for the nonlinear rate-dependence. The equilibrium stress is assumed to be a rate independent functional of the total strain history. Classical plasticity is utilized with a kinematic hardening rule of the Armstrong-Frederick type. In order to incorporate the amplitude-dependent hardening and softening behavior, a generalized arc length representation is applied [14]. The introduction of an additional kinematic hardening variable facilitates consideration of additional hardening effects resulting from the non-radiality of the input process. Apart from the common yield and loading criterion of classical plasticity, the proposed constitutive model does not contain any further distinction of different cases. The experimental data are sufficient to identify the material parameters of the constitutive model. The results of the identification procedure demonstrate the ability of the model to represent the observed phenomena

  19. Comprehensive Characterization of Palygorskite from Torrejon el Rubio (Spain) Based on Experimental Techniques and Theoretical DFT Studies

    International Nuclear Information System (INIS)

    Fernandez, A.M.; Timon, V.; Cubero, J. J.; Sanchez-Ledesma, D. M.; Gutierrez-Nebot, L.; Martinez, J. J.; Romero, C.; Labajo, M.; Melon, A.; Barrios, I.

    2013-01-01

    New data about the physico-chemical, microstructural and crystal-chemical properties of the mineral paligorskite from Torrejon el Rubio (Caceres, Spain) were obtained by a combination of experimental techniques (XRD, FRX, FTIR, TG-DSC, SEM and chemical analyses), as well as geometry optimization by means of the Density Functional Theory (DFT). This study demonstrates the applicability of the mixed theoretical-experimental work to characterize and understand the properties of clay minerals used in technological applications and environmental remediation. (Author)

  20. Comprehensive Characterization of Palygorskite from Torrejon el Rubio (Spain) Based on Experimental Techniques and Theoretical DFT Studies

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez, A.M.; Timon, V.; Cubero, J. J.; Sanchez-Ledesma, D. M.; Gutierrez-Nebot, L.; Martinez, J. J.; Romero, C.; Labajo, M.; Melon, A.; Barrios, I.

    2013-10-01

    New data about the physico-chemical, microstructural and crystal-chemical properties of the mineral paligorskite from Torrejon el Rubio (Caceres, Spain) were obtained by a combination of experimental techniques (XRD, FRX, FTIR, TG-DSC, SEM and chemical analyses), as well as geometry optimization by means of the Density Functional Theory (DFT). This study demonstrates the applicability of the mixed theoretical-experimental work to characterize and understand the properties of clay minerals used in technological applications and environmental remediation. (Author)

  1. Experimental model for composite tissue allotransplantations Modelo experimental para alotransplantes de tecido composto

    Directory of Open Access Journals (Sweden)

    Lydia Masako Ferreira

    2004-12-01

    Full Text Available In homologous transplantation or allotranplantation of limbs, the great tissue diversity causes variability in the rejection process and, consequently, its immunology is very complex. Thus, limb transplantation is the most used prototype of compound tissue transplantation among the protocols of experimental studies. Composite tissue allotransplantation represents the experimental model to study the homologous transplantation (from an individual to another of vascularized, innervated musclecutaneous units, joints, bone or even the whole member. Groups of rats were undergone allogeneic hindlimb transplantation. The receptors were randomized and control groups were established as: Control Group A: Autograft controls (F344 rats had its limbs reimplanted and no immunosuppressive therapy. Control Group B: Allograft controls (BN rats limbs were transplanted to F344. Composite tissue homotransplantation allows the inclusion of innervated muscle-cutaneous units, joint and bone or even the hole limb, is considerably applicable in cases of congenital absence or deformity, trauma or greater resection due to malignant tumor. For many complex deformities, these transplantations would allow a more precise reconstruction than the current reconstruction techniques.Nos transplantes alógenos de membro a grande variabilidade de tecidos (pele, subcutâneo, músculo, osso, medula óssea, gânglios linfáticos, cartilagem, nervo, vasos, tendão, articulação leva a grande variação dentro do processo de rejeição e consequentemente a sua imunologia é bastante complexa. Os transplantes alógenos de tecido composto representam o modelo experimental para se estudar o transplante homólogo (de um indivíduo para outro de unidades músculo cutâneas inervadas, vascularizadas, articulações, osso ou mesmo de todo o membro. Os receptores foram randomizados e os grupos controle foram estabelecidos como: grupo controle A: transplante autógeno de membro em que ratos F344

  2. ESCOMPTE 2001: multi-scale modelling and experimental validation

    Science.gov (United States)

    Cousin, F.; Tulet, P.; Rosset, R.

    2003-04-01

    ESCOMPTE is a European pollution field experiment located in the Marseille / Fos-Berre area in the summer 2001.This Mediterranean area, with frequent pollution peaks, is characterized by a complex topography subject to sea breeze regimes, together with intense localized urban, industrial and biogenic sources. Four POI have been selected, the most significant being POI2a / b, a 6-day pollution episode extensively documented for dynamics, radiation, gas phase and aerosols, with surface measurements (including measurements at sea in the gulf of Genoa, on board instrumented ferries between Marseille and Corsica), 7 aircrafts, lidar, radar and constant-level flight balloon soundings. The two-way mesoscale model MESO-NH-C (MNH-C), with horizontal resolutions of 9 and 3 km and high vertical resolution (up to 40 levels in the first 2 km), embedded in the global CTM Mocage, has been run for all POIs, with a focus here on POI2b (June 24-27,2001), a typical high pollution episode. The multi-scale modelling system MNH-C+MOCAGE allows to simulate local and regional pollution issued from emission sources in the Marseille / Fos-Berre area as well as from remote sources (e.g. the Po Valley and / or western Mediterranean sources) and their associated transboundary pollution fluxes. Detailed dynamical, chemical and aerosol (both modal and sectional spectra with organics and inorganics) simulations generally favorably compare to surface(continental and on ships), lidar and along-flight aircraft measurements.

  3. Experimental investigation of statistical models describing distribution of counts

    International Nuclear Information System (INIS)

    Salma, I.; Zemplen-Papp, E.

    1992-01-01

    The binomial, Poisson and modified Poisson models which are used for describing the statistical nature of the distribution of counts are compared theoretically, and conclusions for application are considered. The validity of the Poisson and the modified Poisson statistical distribution for observing k events in a short time interval is investigated experimentally for various measuring times. The experiments to measure the influence of the significant radioactive decay were performed with 89 Y m (T 1/2 =16.06 s), using a multichannel analyser (4096 channels) in the multiscaling mode. According to the results, Poisson statistics describe the counting experiment for short measuring times (up to T=0.5T 1/2 ) and its application is recommended. However, analysis of the data demonstrated, with confidence, that for long measurements (T≥T 1/2 ) Poisson distribution is not valid and the modified Poisson function is preferable. The practical implications in calculating uncertainties and in optimizing the measuring time are discussed. Differences between the standard deviations evaluated on the basis of the Poisson and binomial models are especially significant for experiments with long measuring time (T/T 1/2 ≥2) and/or large detection efficiency (ε>0.30). Optimization of the measuring time for paired observations yields the same solution for either the binomial or the Poisson distribution. (orig.)

  4. Exhaustively characterizing feasible logic models of a signaling network using Answer Set Programming.

    Science.gov (United States)

    Guziolowski, Carito; Videla, Santiago; Eduati, Federica; Thiele, Sven; Cokelaer, Thomas; Siegel, Anne; Saez-Rodriguez, Julio

    2013-09-15

    Logic modeling is a useful tool to study signal transduction across multiple pathways. Logic models can be generated by training a network containing the prior knowledge to phospho-proteomics data. The training can be performed using stochastic optimization procedures, but these are unable to guarantee a global optima or to report the complete family of feasible models. This, however, is essential to provide precise insight in the mechanisms underlaying signal transduction and generate reliable predictions. We propose the use of Answer Set Programming to explore exhaustively the space of feasible logic models. Toward this end, we have developed caspo, an open-source Python package that provides a powerful platform to learn and characterize logic models by leveraging the rich modeling language and solving technologies of Answer Set Programming. We illustrate the usefulness of caspo by revisiting a model of pro-growth and inflammatory pathways in liver cells. We show that, if experimental error is taken into account, there are thousands (11 700) of models compatible with the data. Despite the large number, we can extract structural features from the models, such as links that are always (or never) present or modules that appear in a mutual exclusive fashion. To further characterize this family of models, we investigate the input-output behavior of the models. We find 91 behaviors across the 11 700 models and we suggest new experiments to discriminate among them. Our results underscore the importance of characterizing in a global and exhaustive manner the family of feasible models, with important implications for experimental design. caspo is freely available for download (license GPLv3) and as a web service at http://caspo.genouest.org/. Supplementary materials are available at Bioinformatics online. santiago.videla@irisa.fr.

  5. Experimental evaluation of the power balance model of speed skating.

    Science.gov (United States)

    de Koning, Jos J; Foster, Carl; Lampen, Joanne; Hettinga, Floor; Bobbert, Maarten F

    2005-01-01

    Prediction of speed skating performance with a power balance model requires assumptions about the kinetics of energy production, skating efficiency, and skating technique. The purpose of this study was to evaluate these parameters during competitive imitations for the purpose of improving model predictions. Elite speed skaters (n = 8) performed races and submaximal efficiency tests. External power output (P(o)) was calculated from movement analysis and aerodynamic models and ice friction measurements. Aerobic kinetics was calculated from breath-by-breath oxygen uptake (Vo(2)). Aerobic power (P(aer)) was calculated from measured skating efficiency. Anaerobic power (P(an)) kinetics was determined by subtracting P(aer) from P(o). We found gross skating efficiency to be 15.8% (1.8%). In the 1,500-m event, the kinetics of P(an) was characterized by a first-order system as P(an) = 88 + 556e(-0.0494t) (in W, where t is time). The rate constant for the increase in P(aer) was -0.153 s(-1), the time delay was 8.7 s, and the peak P(aer) was 234 W; P(aer) was equal to 234[1 - e(-0.153(t-8.7))] (in W). Skating position changed with preextension knee angle increasing and trunk angle decreasing throughout the event. We concluded the pattern of P(aer) to be quite similar to that reported during other competitive imitations, with the exception that the increase in P(aer) was more rapid. The pattern of P(an) does not appear to fit an "all-out" pattern, with near zero values during the last portion of the event, as assumed in our previous model (De Koning JJ, de Groot G, and van Ingen Schenau GJ. J Biomech 25: 573-580, 1992). Skating position changed in ways different from those assumed in our previous model. In addition to allowing improved predictions, the results demonstrate the importance of observations in unique subjects to the process of model construction.

  6. Evaluation of soil flushing of complex contaminated soil: An experimental and modeling simulation study

    Energy Technology Data Exchange (ETDEWEB)

    Yun, Sung Mi; Kang, Christina S. [Department of Environmental Engineering, Konkuk University, 120 Neungdong-ro, Gwangjin-gu, Seoul 143-701 (Korea, Republic of); Kim, Jonghwa [Department of Industrial Engineering, Konkuk University, 120 Neungdong-ro, Gwangjin-gu, Seoul 143-701 (Korea, Republic of); Kim, Han S., E-mail: hankim@konkuk.ac.kr [Department of Environmental Engineering, Konkuk University, 120 Neungdong-ro, Gwangjin-gu, Seoul 143-701 (Korea, Republic of)

    2015-04-28

    Highlights: • Remediation of complex contaminated soil achieved by sequential soil flushing. • Removal of Zn, Pb, and heavy petroleum oils using 0.05 M citric acid and 2% SDS. • Unified desorption distribution coefficients modeled and experimentally determined. • Nonequilibrium models for the transport behavior of complex contaminants in soils. - Abstract: The removal of heavy metals (Zn and Pb) and heavy petroleum oils (HPOs) from a soil with complex contamination was examined by soil flushing. Desorption and transport behaviors of the complex contaminants were assessed by batch and continuous flow reactor experiments and through modeling simulations. Flushing a one-dimensional flow column packed with complex contaminated soil sequentially with citric acid then a surfactant resulted in the removal of 85.6% of Zn, 62% of Pb, and 31.6% of HPO. The desorption distribution coefficients, K{sub Ubatch} and K{sub Lbatch}, converged to constant values as C{sub e} increased. An equilibrium model (ADR) and nonequilibrium models (TSNE and TRNE) were used to predict the desorption and transport of complex contaminants. The nonequilibrium models demonstrated better fits with the experimental values obtained from the column test than the equilibrium model. The ranges of K{sub Ubatch} and K{sub Lbatch} were very close to those of K{sub Ufit} and K{sub Lfit} determined from model simulations. The parameters (R, β, ω, α, and f) determined from model simulations were useful for characterizing the transport of contaminants within the soil matrix. The results of this study provide useful information for the operational parameters of the flushing process for soils with complex contamination.

  7. Synthesis and characterization of sulfolane-based amino alcohols: A combined experimental and computational study

    Science.gov (United States)

    Palchykov, Vitalii A.; Zarovnaya, Iryna S.; Tretiakov, Serhii V.; Reshetnyak, Alyona V.; Omelchenko, Iryna V.; Shishkin, Oleg V.; Okovytyy, Sergiy I.

    2018-04-01

    Aminolysis of 3,4-epoxysulfolane in aqueous media leads to a very complex mixture of products with unresolved stereochemistry. Herein, we report a detailed theoretical and experimental mechanistic investigation of this reaction along with extensive spectroscopic characterization of the resulting amino alcohols, using 1D and 2D NMR techniques (1H, 13C, NOE, NOESY, COSY, HSQC, HMBC) as well as XRD analysis. In addition to simple amines such as ammonia and benzylamine, our study also employed the more sterically hindered endo-bicyclo[2.2.1]hept-5-en-2-ylmethanamine. The mechanism of the aminolysis of 3,4-epoxysulfolane by aqueous ammonia was studied in more detail using quantum chemical calculations at the M06-2X/6-31++G** level of theory. The computational results led us to conclude that the most probable way of initial epoxide transformation is base-catalyzed rearrangement to a corresponding allylic alcohol. Subsequent formation of vicinal amino alcohols and diols proceeds via addition of ammonia or hydroxy-anions to activated double Cdbnd C bond with some preference of a cis-attack. Detailed analytical data obtained in the course of our work will be useful for the stereochemical identification of new sulfolane derivatives.

  8. Structural characterization of the gallery forest of the Guisa Agroforestry Experimental Station

    Directory of Open Access Journals (Sweden)

    José Luis Rodríguez Sosa

    2018-01-01

    Full Text Available The work was carried out in the gallery forest of the Cupaynicú stream, belonging to the Guisa Agroforestry Experimental Station, with the objective of characterizing its structure. Eight parcels of 500 m2 were randomly raised, in them the species were identified, their height and diameter were measured. The flora was analyzed through the origin of the species and the frequency histogram. The structure of the forest was analyzed through the diametric structure and the Value Index of Ecological Importance, the vertical structure was described taking into consideration the forest strata as well as the preparation of the canopy diagram. A descriptive analysis of the parameters diameter, height and basal area was made to study the parametric structure. The richness of the riparian forest was evidenced by the registry of 25 families, 40 genera and 43 species, as well as the predominance of the Meliaceae family followed by Lauraceae, Mimosaceae and Sapindaceae, which reflects the high timber value, melliferous and ecological of the same. The species Roystonea regia, Sterculiaapetala, Dendropanaxarboreus, Andirainermis and Mangifera indica, determine the physiognomy of the gallery Forest. The trees reach 33 cm in diameter and 18.27 m in height on average, although the presence of trees with 30 m is the most frequent, which denotes the irregular structure of the forest.

  9. Aerosols from metal cutting techniques typical of decommissioning nuclear facilities - experimental system for collection and characterization

    International Nuclear Information System (INIS)

    Newton, G.J.; Hoover, M.D.; Barr, E.B.; Wong, B.A.; Ritter, P.D.

    1982-01-01

    Decommissioning of radioactively contaminated sites has the potential for creating radioactive and other potentially toxic aerosols. We describe an experimental system to collect and characterize aerosols from metal cutting activities typical of those used in decommissioning of nuclear facilities. A special enclosure was designed for the experiment and consisted of a 2-in. x 4-in. stud frame with double walls of flame retardant polyethylene film. Large plexiglass windows allowed the cutting operations to be directed and filmed. Ventilation was 8500 L/min (300 CFM) exhausted through HEPA filters. Seven cutting techniques were evaluated: pipe cutter, reciprocating saw, band saw, chop saw, oxy-acetylene torch, electric arc cut rod and plasma torch. Two grinding tools were also evaluated. Materials cut were 2-, 3- and 4-in. dia schedule 40, 80 and 180 type 304L stainless steel pipe. Basic studies were done on uncontaminated pipe. Four-inch-diameter sections of schedule 180 type 304L stainless steel pipe with radioactively contaminated internal surfaces were also cut. The experiments controlled important variables including tools, cutting technique, and type and thickness of material. 15 references, 4 figures, 2 tables

  10. Experimental characterization of a solar cooker with thermal energy storage based on solar salt

    Science.gov (United States)

    Coccia, G.; Di Nicola, G.; Tomassetti, S.; Gabrielli, G.; Chieruzzi, M.; Pierantozzi, M.

    2017-11-01

    High temperature solar cooking allows to cook food fast and with good efficiency. An unavoidable drawback of this technology is that it requires nearly clear-sky conditions. In addition, evening cooking is difficult to be accomplished, particularly on the winter season during which solar radiation availability is limited to a few hours in the afternoon in most of countries. These restrictions could be overcome using a cooker thermal storage unit (TSU). In this work, a TSU based on solar salt was studied. The unit consists of two metal concentric cylindrical vessels, connected together to form a double-walled vessel. The volume between walls was filled with a certain amount of nitrate based phase change material (solar salt). In order to characterize the TSU, a test bench used to assess solar cooker performance was adopted. Experimental load tests with the TSU were carried out to evaluate the cooker performance. The obtained preliminary results show that the adoption of the solar salt TSU seems to allow both the opportunity of evening cooking and the possibility to better stabilize the cooker temperature when sky conditions are variable.

  11. Design and experimental characterization of a 350 W High Temperature PEM fuel cell stack

    Directory of Open Access Journals (Sweden)

    Nicola Zuliani

    2011-01-01

    Full Text Available High Temperature Proton Exchange Membrane (HT PEM fuel cell based on polybenzimidazole (PBI polymer and phosphoric acid, can be operated at temperature between 120 °C and 180 °C. Reactants humidification is not required and CO content up to 2% in the fuel can be tolerated, affecting only marginally performance. This is what makes HT PEM very attractive, as low quality reformed hydrogen can be used and water management problems are avoided. Till nowadays, from experimental point of view, only few studies relate to the development and characteri