WorldWideScience

Sample records for volumetric heating rates

  1. Volumetric Growth Rate of Recurrent Pleomorphic Adenoma.

    Science.gov (United States)

    Naunheim, Molly; Wu, Xin; Ryan, William R; Wang, Steven J; Heaton, Chase M

    2017-07-01

    Surgery for recurrent pleomorphic adenoma (PA) can be challenging and may increase the risk of operative complications, particularly facial nerve weakness. As observation may be a viable alternative to surgery for slow-growing tumors, our objective was to assess the growth rate of recurrent PAs. This study is a case series of patients at our tertiary academic medical center with recurrent PA. Two magnetic resonance images (MRI) were compared; total volume (TV) of recurrent tumor on both studies was calculated to obtain our main outcomes of percent change in TV and tumor growth rate. Fourteen patients with recurrent PA had a median interval time between MRI of 12.8 months. Though growth rates were variable, the median continuous compound growth per year was 10.2%. Notably, 3 patients (21%) had no growth, and 2 patients (14%) had a reduction in TV. The median growth rate for enlarging tumors is estimated at 10.2% per year. Due to variability, tumor growth rate should be estimated on an individual patient basis. For slow-growing tumors, physicians may weigh the risk of this slow growth with the morbidity of reoperation.

  2. Video-rate volumetric optical coherence tomography-based microangiography

    Science.gov (United States)

    Baran, Utku; Wei, Wei; Xu, Jingjiang; Qi, Xiaoli; Davis, Wyatt O.; Wang, Ruikang K.

    2016-04-01

    Video-rate volumetric optical coherence tomography (vOCT) is relatively young in the field of OCT imaging but has great potential in biomedical applications. Due to the recent development of the MHz range swept laser sources, vOCT has started to gain attention in the community. Here, we report the first in vivo video-rate volumetric OCT-based microangiography (vOMAG) system by integrating an 18-kHz resonant microelectromechanical system (MEMS) mirror with a 1.6-MHz FDML swept source operating at ˜1.3 μm wavelength. Because the MEMS scanner can offer an effective B-frame rate of 36 kHz, we are able to engineer vOMAG with a video rate up to 25 Hz. This system was utilized for real-time volumetric in vivo visualization of cerebral microvasculature in mice. Moreover, we monitored the blood perfusion dynamics during stimulation within mouse ear in vivo. We also discussed this system's limitations. Prospective MEMS-enabled OCT probes with a real-time volumetric functional imaging capability can have a significant impact on endoscopic imaging and image-guided surgery applications.

  3. Analysis of Changing Swarm Rate using Volumetric Strain

    Science.gov (United States)

    Kumazawa, T.; Ogata, Y.; Kimura, K.; Maeda, K.; Kobayashi, A.

    2015-12-01

    Near the eastern coast of Izu peninsula is an active submarine volcanic region in Japan, where magma intrusions have been observed many times. The forecast of earthquake swarm activities and eruptions are serious concern particularly in nearby hot spring resort areas. It is well known that temporal durations of the swarm activities have been correlated with early volumetric strain changes at a certain observation station of about 20 km distance apart. Therefore the Earthquake Research Committee (2010) investigated some empirical statistical relations to predict sizes of the swarm activity. Here we looked at the background seismicity rate changes during these swarm periods using the non-stationary ETAS model (Kumazawa and Ogata, 2013, 2014), and have found the followings. The modified volumetric strain data, by removing the effect of earth tides, precipitation and coseismic jumps, have significantly higher cross-correlations to the estimated background rates of the ETAS model than to the swarm rate-changes. Specifically, the background seismicity rate synchronizes clearer to the strain change by the lags around a half day. These relations suggest an enhanced prediction of earthquakes in this region using volumetric strain measurements. Hence we propose an extended ETAS model where the background rate is modulated by the volumetric strain data. We have also found that the response function to the strain data can be well approximated by an exponential functions with the same decay rate, but that their intersects are inversely proportional to the distances between the volumetric strain-meter and the onset location of the swarm. Our numerical results by the same proposed model show consistent outcomes for the various major swarms in this region.

  4. The Volumetric Rate of Superluminous Supernovae at z~1

    CERN Document Server

    Prajs, S; Smith, M; Levan, A; Karpenka, N V; Edwards, T D P; Walker, C R; Wolf, W M; Balland, C; Carlberg, R; Howell, A; Lidman, C; Pain, R; Pritchet, C; Ruhlmann-Kleider, V

    2016-01-01

    We present a measurement of the volumetric rate of superluminous supernovae (SLSNe) at z~1, measured using archival data from the first four years of the Canada-France-Hawaii Telescope Supernova Legacy Survey (SNLS). We develop a method for the photometric classification of SLSNe to construct our sample. Our sample includes two previously spectroscopically-identified objects, and a further new candidate selected using our classification technique. We use the point-source recovery efficiencies from Perrett et.al. (2010) and a Monte Carlo approach to calculate the rate based on our SLSN sample. We find that the three identified SLSNe from SNLS give a rate of 91 (+76/-36) SNe/Yr/Gpc^3 at a volume-weighted redshift of z=1.13. This is equivalent to 2.2 (+1.8/-0.9) x10^-4 of the volumetric core collapse supernova rate at the same redshift. When combined with other rate measurements from the literature, we show that the rate of SLSNe increases with redshift in a manner consistent with that of the cosmic star formati...

  5. The volumetric rate of superluminous supernovae at z ˜ 1

    Science.gov (United States)

    Prajs, S.; Sullivan, M.; Smith, M.; Levan, A.; Karpenka, N. V.; Edwards, T. D. P.; Walker, C. R.; Wolf, W. M.; Balland, C.; Carlberg, R.; Howell, D. A.; Lidman, C.; Pain, R.; Pritchet, C.; Ruhlmann-Kleider, V.

    2017-01-01

    We present a measurement of the volumetric rate of superluminous supernovae (SLSNe) at z ˜ 1.0, measured using archival data from the first four years of the Canada-France-Hawaii Telescope Supernova Legacy Survey (SNLS). We develop a method for the photometric classification of SLSNe to construct our sample. Our sample includes two previously spectroscopically identified objects, and a further new candidate selected using our classification technique. We use the point-source recovery efficiencies from Perrett et al. and a Monte Carlo approach to calculate the rate based on our SLSN sample. We find that the three identified SLSNe from SNLS give a rate of 91^{+76}_{-36} SNe yr-1 Gpc-3 at a volume-weighted redshift of z = 1.13. This is equivalent to 2.2^{+1.8}_{-0.9}× 10^{-4} of the volumetric core-collapse supernova rate at the same redshift. When combined with other rate measurements from the literature, we show that the rate of SLSNe increases with redshift in a manner consistent with that of the cosmic star formation history. We also estimate the rate of ultra-long gamma-ray bursts based on the events discovered by the Swift satellite, and show that it is comparable to the rate of SLSNe, providing further evidence of a possible connection between these two classes of events. We also examine the host galaxies of the SLSNe discovered in SNLS, and find them to be consistent with the stellar-mass distribution of other published samples of SLSNe.

  6. Transient refractory material dissolution by a volumetrically-heated melt

    Energy Technology Data Exchange (ETDEWEB)

    Seiler, Jean Marie, E-mail: jean-marie.seiler@cea.fr [CEA, DEN, DTN, 17 Rue des Martyrs, 38054 Grenoble Cedex 9 (France); Ratel, Gilles [CEA, DEN, DTN, 17 Rue des Martyrs, 38054 Grenoble Cedex 9 (France); Combeau, Hervé [Institut Jean Lamour, UMR 7198, Lorraine University, Ecole des Mines de Nancy, Parc de Saurupt, 54042 Nancy Cedex (France); Gaus-Liu, Xiaoyang; Kretzschmar, Frank; Miassoedov, Alexei [Karlsruhe Institut of Technology, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany)

    2014-12-15

    Highlights: • We describe a test investigating ceramic dissolution by a molten non-eutectic melt. • The evolution of the interface temperature between melt and refractory is measured. • A theoretical model describing dissolution kinetics is proposed. • When dissolution stops, interface temperature is the liquidus temperature of the melt. - Abstract: The present work addresses the question of corium–ceramic interaction in a core catcher during a core-melt accident in a nuclear power plant. It provides an original insight into transient aspects concerning dissolution of refractory material by a volumetrically heated pool. An experiment with simulant material (LIVECERAM) is presented. Test results clearly show that dissolution of solid refractory material can occur in a non-eutectic melt at a temperature which is lower than the melting temperature of the refractory material. During the dissolution transient, the interface temperature rises above the liquidus temperature, corresponding to the instantaneous average composition of the melt pool. With constant power dissipation in the melt and external cooling of the core-catcher, a final steady-state situation is reached. Dissolution stops when the heat flux (delivered by the melt to the refractory) can be removed by conduction through the residual thickness of the ceramic, with T{sub interface} = T{sub liquidus} (calculated for the average composition of the final liquid pool). The final steady state corresponds to a uniform pool composition and uniform interface temperature distribution. Convection in the pool is governed by natural thermal convection and the heat flux distribution is therefore similar to what would be obtained for a single component pool. An interpretation of the experiment with two model-based approaches (0D and 1D) is presented. The mass transfer kinetics between the interface and the bulk is controlled by a diffusion sublayer within the boundary layer. During the dissolution transient

  7. Study of Volumetrically Heated Ultra-High Energy Density Plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Rocca, Jorge J. [Colorado State Univ., Fort Collins, CO (United States)

    2016-10-27

    Heating dense matter to millions of degrees is important for applications, but requires complex and expensive methods. The major goal of the project was to demonstrate using a compact laser the creation of a new ultra-high energy density plasma regime characterized by simultaneous extremely high temperature and high density, and to study it combining experimental measurements and advanced simulations. We have demonstrated that trapping of intense femtosecond laser pulses deep within ordered nanowire arrays can heat near solid density matter into a new ultra hot plasma regime. Extreme electron densities, and temperatures of several tens of million degrees were achieved using laser pulses of only 0.5 J energy from a compact laser. Our x-ray spectra and simulations showed that extremely highly ionized plasma volumes several micrometers in depth are generated by irradiation of gold and Nickel nanowire arrays with femtosecond laser pulses of relativistic intensities. We obtained extraordinarily high degrees of ionization (e.g. we peeled 52 electrons from gold atoms, and up to 26 electrons from nickel atoms). In the process we generated Gigabar pressures only exceeded in the central hot spot of highly compressed thermonuclear fusion plasmas.. The plasma created after the dissolved wires expand, collide, and thermalize, is computed to have a thermal energy density of 0.3 GJ cm-3 and a pressure of 1-2 Gigabar. These are pressures only exceeded in highly compressed thermonuclear fusion plasmas. Scaling these results to higher laser intensities promises to create plasmas with temperatures and pressures exceeding those in the center of the sun.

  8. Effects of gas bubble production on heat transfer from a volumetrically heated liquid pool

    Science.gov (United States)

    Bull, Geoffrey R.

    Aqueous solutions of uranium salts may provide a new supply chain to fill potential shortfalls in the availability of the most common radiopharmaceuticals currently in use worldwide, including Tc99m which is a decay product of Mo99. The fissioning of the uranium in these solutions creates Mo99 but also generates large amounts of hydrogen and oxygen from the radiolysis of the water. When the dissolved gases reach a critical concentration, bubbles will form in the solution. Bubbles in the solution affect both the fission power and the heat transfer out of the solution. As a result, for safety and production calculations, the effects of the bubbles on heat transfer must be understood. A high aspect ratio tank was constructed to simulate a section of an annulus with heat exchangers on the inner and outer steel walls to provide cooling. Temperature measurements via thermocouples inside the tank and along the outside of the steel walls allowed the calculation of overall and local heat transfer coefficients. Different air injection manifolds allowed the exploration of various bubble characteristics and patterns on heat transfer from the pool. The manifold type did not appear to have significant impact on the bubble size distributions in water. However, air injected into solutions of magnesium sulfate resulted in smaller bubble sizes and larger void fractions than those in water at the same injection rates. One dimensional calculations provide heat transfer coefficient values as functions of the superficial gas velocity in the pool.

  9. Correlation dependence of the volumetric thermal expansion coefficient of metallic aluminum on its heat capacity

    Science.gov (United States)

    Bodryakov, V. Yu.; Bykov, A. A.

    2016-05-01

    The correlation between the volumetric thermal expansion coefficient β( T) and the heat capacity C( T) of aluminum is considered in detail. It is shown that a clear correlation is observed in a significantly wider temperature range, up to the melting temperature of the metal, along with the low-temperature range where it is linear. The significant deviation of dependence β( C) from the low-temperature linear behavior is observed up to the point where the heat capacity achieves the classical Dulong-Petit limit of 3 R ( R is the universal gas constant).

  10. Volumetric Examination of MS Plaques and Correlation with EDSS Ratings.

    Science.gov (United States)

    Gurwara, S; Hailey, B; Thompson, A; Minagar, A; Hardjasudarma, M; Gonzalez-Toledo, E

    2009-05-15

    This study is a retrospective analysis of 17 patients with multiple sclerosis. The total volume of plaques from three different MR image sets of the brain was correlated with the EDSS ratings of the patients. Each of the correlations showed a positive relationship, but none was statistically significant. A more extensive study is required in order to give significance to these relationships.

  11. Integral transform solution of natural convection in a square cavity with volumetric heat generation

    Directory of Open Access Journals (Sweden)

    C. An

    2013-12-01

    Full Text Available The generalized integral transform technique (GITT is employed to obtain a hybrid numerical-analytical solution of natural convection in a cavity with volumetric heat generation. The hybrid nature of this approach allows for the establishment of benchmark results in the solution of non-linear partial differential equation systems, including the coupled set of heat and fluid flow equations that govern the steady natural convection problem under consideration. Through performing the GITT, the resulting transformed ODE system is then numerically solved by making use of the subroutine DBVPFD from the IMSL Library. Therefore, numerical results under user prescribed accuracy are obtained for different values of Rayleigh numbers, and the convergence behavior of the proposed eigenfunction expansions is illustrated. Critical comparisons against solutions produced by ANSYS CFX 12.0 are then conducted, which demonstrate excellent agreement. Several sets of reference results for natural convection with volumetric heat generation in a bi-dimensional square cavity are also provided for future verification of numerical results obtained by other researchers.

  12. Finite element analysis of volumetrically heated fluids in an axisymmetric enclosure

    Energy Technology Data Exchange (ETDEWEB)

    Gartling, D.K.

    1979-01-01

    A general purpose finite element computer code has been used to analyze the steady state and transient response of a confined fluid that is heated volumetrically. The numerical procedure is demonstrated to be capable of resolving flow fields of considerable complexity without undue computational expense. Results are discussed for a Grashof number range (4.0 x 10/sup 4/ to 4.0 x 10/sup 6/) in which the flow varies from a steady, single cell configuration to a multiple cell configuration that includes a periodic interaction.

  13. Volumetric flow rate comparisons for water and product on pasteurization systems.

    Science.gov (United States)

    Schlesser, J E; Stroup, W H; McKinstry, J A

    1994-04-01

    A flow calibration tube system was assembled to determine the volumetric flow rates for water and various dairy products through a holding tube, using three different flow promotion methods. With the homogenizer, the volumetric flow rates of water and reconstituted skim milk were within 1.5% of each other. With the positive displacement pump, the flow rate for reconstituted skim milk increased compared with that for water as the pressure increased or temperature decreased. The largest increase in flow rate was at 310-kPa gauge and 20 degrees C. On a magnetic flow meter system, the volumetric flow rates of water and reconstituted skim milk were within .5% of the flow rate measured from the volume collected in a calibrated tank. The flow rate of whole milk was similar to that of skim milk on the three flow promoters evaluated. Ice milk mix increased the flow rate of the positive displacement pump, but not the homogenizer and magnetic flow meter system.

  14. Dimensioning of ducts for maximal volumetric heat transfer taking both laminar and turbulent flow possibilities into consideration

    Science.gov (United States)

    Yilmaz, Alper

    2015-04-01

    It is intended to design compact heat exchangers which can transfer high heat flow for a given volume and temperature difference with high efficiency. This work presents the optimal design of heat exchangers for a given length or hydraulic diameter with a constraint of a certain pressure loss and constant wall temperature. Both volumetric heat transfer and heat transfer efficiency are taken into consideration for the design in laminar or turbulent flow regions. Equations are derived which easily enable optimal design for all shapes of ducts and for all Pr numbers. It is found that optimum conditions for turbulent flow is possible for all duct hydraulic diameters; however, it is possible to have optimum conditions till a certain dimensionless duct hydraulic diameter for laminar flow. Besides maximal volumetric heat flow, heat transfer efficiency should be taken into consideration in turbulent flow for optimum design.

  15. Predicting Offshore Swarm Rate Changes by Volumetric Strain Changes in Izu Peninsula, Japan

    Science.gov (United States)

    Kumazawa, T.; Ogata, Y.; Kimura, Y.; Maeda, K.; Kobayashi, A.

    2014-12-01

    The eastern offshore of Izu peninsula is one of the well known volcanic active regions in Japan, where magma intrusions have been observed several times since 1980s monitored by strain-meters located nearby. Major swarm activities have been synchronously associated with coseismic and preseismic significant sizes of a volumetric strain changes (Earthquake Research Committee, 2010). We investigated the background seismicity changes during these earthquake swarms using the nonstationary ETAS model (Kumazawa and Ogata, 2013), and have found the followings. The modified volumetric strain change data by removing the effect of earth tides and precipitation as well as removing coseismic jumps have much higher cross-correlations to the background rates of the ETAS model than to the whole seismicity rate change of the ETAS, and further the strain changes precede the background seismicity by lag of about a day. This relation suggests an enhanced prediction of earthquakes in this region using volumetric strain measurements. Thus we propose an extended ETAS model where the background seismicity rate is predicted by the time series of preceding volumetric strain changes. Our numerical results for Izu region show consistent outcomes throughout the major swarms in this region. References Earthquake Research Committee (2010). Report on "Prediction of seismic activity in the Izu Eastern Region" (in Japanese), http://www.jishin.go.jp/main/yosoku/izu/index.htm Kumazawa, T. and Ogata, Y. (2013). Quantitative description of induced seismic activity before and after the 2011 Tohoku-Oki earthquake by nonstationary ETAS model, J Geophys.Res. 118, 6165-6182.

  16. Validation of the generalized model of two-phase thermosyphon loop based on experimental measurements of volumetric flow rate

    Science.gov (United States)

    Bieliński, Henryk

    2016-09-01

    The current paper presents the experimental validation of the generalized model of the two-phase thermosyphon loop. The generalized model is based on mass, momentum, and energy balances in the evaporators, rising tube, condensers and the falling tube. The theoretical analysis and the experimental data have been obtained for a new designed variant. The variant refers to a thermosyphon loop with both minichannels and conventional tubes. The thermosyphon loop consists of an evaporator on the lower vertical section and a condenser on the upper vertical section. The one-dimensional homogeneous and separated two-phase flow models were used in calculations. The latest minichannel heat transfer correlations available in literature were applied. A numerical analysis of the volumetric flow rate in the steady-state has been done. The experiment was conducted on a specially designed test apparatus. Ultrapure water was used as a working fluid. The results show that the theoretical predictions are in good agreement with the measured volumetric flow rate at steady-state.

  17. 4D ultrafast ultrasound flow imaging: in vivo quantification of arterial volumetric flow rate in a single heartbeat

    Science.gov (United States)

    Correia, Mafalda; Provost, Jean; Tanter, Mickael; Pernot, Mathieu

    2016-12-01

    We present herein 4D ultrafast ultrasound flow imaging, a novel ultrasound-based volumetric imaging technique for the quantitative mapping of blood flow. Complete volumetric blood flow distribution imaging was achieved through 2D tilted plane-wave insonification, 2D multi-angle cross-beam beamforming, and 3D vector Doppler velocity components estimation by least-squares fitting. 4D ultrafast ultrasound flow imaging was performed in large volumetric fields of view at very high volume rate (>4000 volumes s-1) using a 1024-channel 4D ultrafast ultrasound scanner and a 2D matrix-array transducer. The precision of the technique was evaluated in vitro by using 3D velocity vector maps to estimate volumetric flow rates in a vessel phantom. Volumetric Flow rate errors of less than 5% were found when volumetric flow rates and peak velocities were respectively less than 360 ml min-1 and 100 cm s-1. The average volumetric flow rate error increased to 18.3% when volumetric flow rates and peak velocities were up to 490 ml min-1 and 1.3 m s-1, respectively. The in vivo feasibility of the technique was shown in the carotid arteries of two healthy volunteers. The 3D blood flow velocity distribution was assessed during one cardiac cycle in a full volume and it was used to quantify volumetric flow rates (375  ±  57 ml min-1 and 275  ±  43 ml min-1). Finally, the formation of 3D vortices at the carotid artery bifurcation was imaged at high volume rates.

  18. The Hubble Space Telescope Cluster Supernova Survey: VI. The Volumetric Type Ia Supernova Rate

    CERN Document Server

    Barbary, K; Amanullah, R; Brodwin, M; Connolly, N; Dawson, K S; Doi, M; Eisenhardt, P; Faccioli, L; Fadeyev, V; Fakhouri, H K; Fruchter, A S; Gilbank, D G; Gladders, M D; Goldhaber, G; Goobar, A; Hattori, T; Hsiao, E; Huang, X; Ihara, Y; Kashikawa, N; Koester, B; Konishi, K; Kowalski, M; Lidman, C; Lubin, L; Meyers, J; Morokuma, T; Oda, T; Panagia, N; Perlmutter, S; Postman, M; Ripoche, P; Rosati, P; Rubin, D; Schlegel, D J; Spadafora, A L; Stanford, S A; Strovink, M; Suzuki, N; Takanashi, N; Tokita, K; Yasuda, N

    2011-01-01

    We present a measurement of the volumetric Type Ia supernova (SN Ia) rate out to z ~ 1.6 from the Hubble Space Telescope Cluster Supernova Survey. In observations spanning 189 orbits with the Advanced Camera for Surveys we discovered 29 SNe, of which approximately 20 are SNe Ia. Twelve of these SNe Ia are located in the foregrounds and backgrounds of the clusters targeted in the survey. Using these new data, we derive the volumetric SN Ia rate in four broad redshift bins, finding results consistent with previous measurements at z > 1 and strengthening the case for a SN Ia rate that is equal to or greater than ~0.6 x 10^-4/yr/Mpc^3 at z ~ 1 and flattening out at higher redshift. We provide SN candidates and efficiency calculations in a form that makes it easy to rebin and combine these results with other measurements for increased statistics. Finally, we compare the assumptions about host-galaxy dust extinction used in different high-redshift rate measurements, finding that different assumptions may induce sig...

  19. A Stable Carbon Nanotube Nanofluid for Latent Heat-Driven Volumetric Absorption Solar Heating Applications

    OpenAIRE

    Nathan Hordy; Delphine Rabilloud; Jean-Luc Meunier; Sylvain Coulombe

    2015-01-01

    Recently, direct solar collection through the use of broadly absorbing nanoparticle suspensions (known as nanofluids) has been shown as a promising method to improve efficiencies in solar thermal devices. By utilizing a volatile base fluid, this concept could also be applied to the development of a direct absorption heat pipe for an evacuated tube solar collector. However, for this to happen or for any other light-induced vapor production applications, the nanofluid must remain stable over ex...

  20. Evolution in the Volumetric Type Ia Supernova Rate from the Supernova Legacy Survey

    CERN Document Server

    Perrett, K; Conley, A; Gonzalez-Gaitan, S; Carlberg, R; Fouchez, D; Ripoche, P; Neill, J D; Astier, P; Balam, D; Balland, C; Basa, S; Guy, J; Hardin, D; Hook, I M; Howell, D A; Pain, R; Palanque-Delabrouille, N; Pritchet, C; Regnault, N; Rich, J; Ruhlmann-Kleider, V; Baumont, S; Lidman, C; Perlmutter, S; Walker, E S

    2012-01-01

    We present a measurement of the volumetric Type Ia supernova (SN Ia) rate (SNR_Ia) as a function of redshift for the first four years of data from the Canada-France-Hawaii Telescope (CFHT) Supernova Legacy Survey (SNLS). This analysis includes 286 spectroscopically confirmed and more than 400 additional photometrically identified SNe Ia within the redshift range 0.1volumetric SNR_Ia evolution is consistent with a rise to z~1.0 that follows a power-law of the form (1+z)^alpha, with alpha=2.11+/-0.28. This evolutionary trend in the SNLS rates is slightly shallower than that of the cosmic star-formation history over the same redshift range. We combine the SNLS rate measurements with those from other surveys that complement the SNLS redshift range, and fit various simple SN Ia delay-time distribution (DTD) models to the combined data. A simple power-law model for the DTD (i.e., proportional to t^-beta) yields values from beta=0.98+/-0.05 to beta=1.15+/-0.08 depending on the parameterization of t...

  1. A Stable Carbon Nanotube Nanofluid for Latent Heat-Driven Volumetric Absorption Solar Heating Applications

    Directory of Open Access Journals (Sweden)

    Nathan Hordy

    2015-01-01

    Full Text Available Recently, direct solar collection through the use of broadly absorbing nanoparticle suspensions (known as nanofluids has been shown as a promising method to improve efficiencies in solar thermal devices. By utilizing a volatile base fluid, this concept could also be applied to the development of a direct absorption heat pipe for an evacuated tube solar collector. However, for this to happen or for any other light-induced vapor production applications, the nanofluid must remain stable over extended periods of time at high temperatures and throughout repetitive evaporation/condensation cycles. In this work, we report for the first time a nanofluid consisting of plasma-functionalized multiwalled carbon nanotubes (MWCNTs suspended in denatured alcohol, which achieves this required stability. In addition, optical characterization of the nanofluid demonstrates that close to 100% of solar irradiation can be absorbed over a relatively small nanofluid thickness.

  2. Eddy current pulsed phase thermography considering volumetric induction heating for delamination evaluation in carbon fiber reinforced polymers

    Science.gov (United States)

    Yang, Ruizhen; He, Yunze

    2015-06-01

    Anisotropy and inhomogeneity of carbon fiber reinforced polymers (CFRPs) result in that many traditional non-destructive inspection techniques are inapplicable on the delamination evaluation. This letter introduces eddy current pulsed phase thermography (ECPPT) for CFRPs evaluation considering volumetric induction heating due to small electrical conductivity, abnormal thermal wave propagation, and Fourier analysis. The proposed methods were verified through experimental studies under transmission and reflection modes. Using ECPPT, the influence of the non-uniform heating effect and carbon fiber structures can be suppressed, and then delamination detectability can be improved dramatically over eddy current pulsed thermography.

  3. Rate distortion optimal bit allocation methods for volumetric data using JPEG 2000.

    Science.gov (United States)

    Kosheleva, Olga M; Usevitch, Bryan E; Cabrera, Sergio D; Vidal, Edward

    2006-08-01

    Computer modeling programs that generate three-dimensional (3-D) data on fine grids are capable of generating very large amounts of information. These data sets, as well as 3-D sensor/measured data sets, are prime candidates for the application of data compression algorithms. A very flexible and powerful compression algorithm for imagery data is the newly released JPEG 2000 standard. JPEG 2000 also has the capability to compress volumetric data, as described in Part 2 of the standard, by treating the 3-D data as separate slices. As a decoder standard, JPEG 2000 does not describe any specific method to allocate bits among the separate slices. This paper proposes two new bit allocation algorithms for accomplishing this task. The first procedure is rate distortion optimal (for mean squared error), and is conceptually similar to postcompression rate distortion optimization used for coding codeblocks within JPEG 2000. The disadvantage of this approach is its high computational complexity. The second bit allocation algorithm, here called the mixed model (MM) approach, mathematically models each slice's rate distortion curve using two distinct regions to get more accurate modeling at low bit rates. These two bit allocation algorithms are applied to a 3-D Meteorological data set. Test results show that the MM approach gives distortion results that are nearly identical to the optimal approach, while significantly reducing computational complexity.

  4. Heat capacities and volumetric changes in the glass transition range: a constitutive approach based on the standard linear solid

    Science.gov (United States)

    Lion, Alexander; Mittermeier, Christoph; Johlitz, Michael

    2017-09-01

    A novel approach to represent the glass transition is proposed. It is based on a physically motivated extension of the linear viscoelastic Poynting-Thomson model. In addition to a temperature-dependent damping element and two linear springs, two thermal strain elements are introduced. In order to take the process dependence of the specific heat into account and to model its characteristic behaviour below and above the glass transition, the Helmholtz free energy contains an additional contribution which depends on the temperature history and on the current temperature. The model describes the process-dependent volumetric and caloric behaviour of glass-forming materials, and defines a functional relationship between pressure, volumetric strain, and temperature. If a model for the isochoric part of the material behaviour is already available, for example a model of finite viscoelasticity, the caloric and volumetric behaviour can be represented with the current approach. The proposed model allows computing the isobaric and isochoric heat capacities in closed form. The difference c_p -c_v is process-dependent and tends towards the classical expression in the glassy and equilibrium ranges. Simulations and theoretical studies demonstrate the physical significance of the model.

  5. Feasibility study of volumetric modulated arc therapy with constant dose rate for endometrial cancer

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Ruijie [Department of Radiation Oncology, Peking University Third Hospital, Beijing (China); Wang, Junjie, E-mail: junjiewang47@yahoo.com [Department of Radiation Oncology, Peking University Third Hospital, Beijing (China); Xu, Feng [Department of Biomedical Engineering, Peking University Third Hospital, Beijing (China); Li, Hua [Department of Obstetrics and Gynecology, Peking University Third Hospital, Beijing (China); Zhang, Xile [Department of Radiation Oncology, Peking University Third Hospital, Beijing (China)

    2013-10-01

    To investigate the feasibility, efficiency, and delivery accuracy of volumetric modulated arc therapy with constant dose rate (VMAT-CDR) for whole-pelvic radiotherapy (WPRT) of endometrial cancer. The nine-field intensity-modulated radiotherapy (IMRT), VMAT with variable dose-rate (VMAT-VDR), and VMAT-CDR plans were created for 9 patients with endometrial cancer undergoing WPRT. The dose distribution of planning target volume (PTV), organs at risk (OARs), and normal tissue (NT) were compared. The monitor units (MUs) and treatment delivery time were also evaluated. For each VMAT-CDR plan, a dry run was performed to assess the dosimetric accuracy with MatriXX from IBA. Compared with IMRT, the VMAT-CDR plans delivered a slightly greater V{sub 20} of the bowel, bladder, pelvis bone, and NT, but significantly decreased the dose to the high-dose region of the rectum and pelvis bone. The MUs decreased from 1105 with IMRT to 628 with VMAT-CDR. The delivery time also decreased from 9.5 to 3.2 minutes. The average gamma pass rate was 95.6% at the 3%/3 mm criteria with MatriXX pretreatment verification for 9 patients. VMAT-CDR can achieve comparable plan quality with significant shorter delivery time and smaller number of MUs compared with IMRT for patients with endometrial cancer undergoing WPRT. It can be accurately delivered and be an alternative to IMRT on the linear accelerator without VDR capability.

  6. An Experimental study of the initial volumetric strain rate effect on the creep behaviour of reconstituted clays

    Science.gov (United States)

    Bagheri, M.; Rezania, M.; Nezhad, M. M.

    2015-09-01

    Clayey soils tend to undergo continuous compression with time, even after excess pore pressures have substantially dissipated. The effect of time on deformation and mechanical response of these soft soils has been the subject of numerous studies. Based on these studies, the observed time-dependent behaviour of clays is mainly related to the evolution of soil volume and strength characteristics with time, which are classified as creep and/or relaxation properties of the soil. Apart from many empirical relationships that have been proposed in the literature to capture the rheological behaviour of clays, a number of viscid constitutive relationships have also been developed which have more attractive theoretical attributes. A particular feature of these viscid models is that their creep parameters often have clear physical meaning (e.g. coefficient of secondary compression, Cα). Sometimes with these models, a parameter referred to as initial/reference volumetric strain rate, has also been alluded as a model parameter. However, unlike Cα, the determination of and its variations with stress level is not properly documented in the literature. In an attempt to better understand , this paper presents an experimental investigation of the reference volumetric strain rate in reconstituted clay specimens. A long-term triaxial creep test, at different shear stress levels and different strain rates, was performed on clay specimen whereby the volumetric strain rate was measured. The obtained results indicated the stress-level dependency and non-linear variation of with time.

  7. Follow-up after gamma knife radiosurgery for vestibular schwannomas: volumetric and axial control rates

    NARCIS (Netherlands)

    Timmer, F.C.A.; Hanssens, P.E.; Haren, A.E. van; Overbeeke, J.J. van; Mulder, J.J.S.; Cremers, C.W.R.J.; Graamans, K.

    2011-01-01

    OBJECTIVES/HYPOTHESIS: A prospective long-term follow-up study was conducted to evaluate the results of gamma knife radiosurgery (GKRS) for vestibular schwannoma (VS) patients. Both axial and volumetric measurements are used to determine tumor size during follow-up. STUDY DESIGN: Individual prospect

  8. Follow-up after gamma knife radiosurgery for vestibular schwannomas: volumetric and axial control rates

    NARCIS (Netherlands)

    Timmer, F.C.A.; Hanssens, P.E.; Haren, A.E. van; Overbeeke, J.J. van; Mulder, J.J.S.; Cremers, C.W.R.J.; Graamans, K.

    2011-01-01

    OBJECTIVES/HYPOTHESIS: A prospective long-term follow-up study was conducted to evaluate the results of gamma knife radiosurgery (GKRS) for vestibular schwannoma (VS) patients. Both axial and volumetric measurements are used to determine tumor size during follow-up. STUDY DESIGN: Individual

  9. Radiative heating rates during AAOE and AASE

    Science.gov (United States)

    Rosenfield, Joan E.

    Radiative transit computations of heating rates utilizing data from the 1987 Airborne Antarctic Ozone Experiment (AAOE) (Tuck et al., 1989) and the 1989 Airborne Arctic Stratospheric Experiment (AASE) (Turco et al., 1990) are described. Observed temperature and ozone profiles and a radiative transfer model are used to compute the heating rates for the Southern Hemisphere during AAOE and the Northern Hemisphere during AASE. The AASE average cooling rates computed inside the vortex are in good agreement with the diabatic cooling rates estimated from the ER-2 profile data for N2O for the AASE period (Schoeberl et al., 1989).

  10. Volumetric initiation of gaseous detonation by radiant heating of suspended microparticles

    Science.gov (United States)

    Efremov, V. P.; Ivanov, M. F.; Kiverin, A. D.; Yakovenko, I. S.

    2016-02-01

    The concept of detonation wave initiation in the local volume of a fuel-gas mixture containing suspended chemically neutral microparticles heated by radiant energy from an external source is proposed. Mechanisms of initiation of the combustion and detonation waves in a region of accumulation of the radiation- heated microparticles have been studied by numerical simulation methods. Criteria that determine geometric dimensions of a region of the two-phase medium, which are necessary for the initiation of detonation waves, are formulated.

  11. Corrosion Rate Monitoring in District Heating Systems

    DEFF Research Database (Denmark)

    Hilbert, Lisbeth Rischel; Nielsen, Lars Vendelbo; Andersen, A.

    2005-01-01

    Quality control in district heating systems to keep uniform corrosion rates low and localized corrosion minimal is based on water quality control. Side-stream units equipped with carbon steel probes for online monitoring were mounted in district heating plants to investigate which techniques would...... be applicable, and if on-line monitoring could improve the quality control. Water quality monitoring was applied as well as corrosion rate monitoring with linear polarization resistance (LPR), electrochemical impedance spectroscopy (EIS), electrical resistance (ER) technique, mass loss and a crevice corrosion...... cell for localized corrosion risk estimation. Important variations in corrosion rate due to changes in make-up water quality were detected with the continuous monitoring provided by ER and crevice cell, while LPR gave unreliable corrosion rates. The acquisition time of two-three days for EIS...

  12. Corrosion Rate Monitoring in District Heating Systems

    DEFF Research Database (Denmark)

    Hilbert, Lisbeth Rischel; Nielsen, Lars Vendelbo; Andersen, A.

    2005-01-01

    Quality control in district heating systems to keep uniform corrosion rates low and localized corrosion minimal is based on water quality control. Side-stream units equipped with carbon steel probes for online monitoring were mounted in district heating plants to investigate which techniques would...... be applicable, and if on-line monitoring could improve the quality control. Water quality monitoring was applied as well as corrosion rate monitoring with linear polarization resistance (LPR), electrochemical impedance spectroscopy (EIS), electrical resistance (ER) technique, mass loss and a crevice corrosion...... cell for localized corrosion risk estimation. Important variations in corrosion rate due to changes in make-up water quality were detected with the continuous monitoring provided by ER and crevice cell, while LPR gave unreliable corrosion rates. The acquisition time of two-three days for EIS...

  13. Direct initiation of gaseous detonation via radiative heating of microparticles volumetrically suspended in the gas

    Science.gov (United States)

    Efremov, V. P.; Ivanov, M. F.; Kiverin, A. D.; Yakovenko, I. S.

    2015-11-01

    We propose a new conceptual approach for direct detonation initiation in the gaseous mixtures seeded with micro particles via the radiative heating from the external energy source. The basic mechanisms of energy absorption, ignition and detonation formation are analyzed numerically on the example of hydrogen-oxygen mixture. Obtained data is very promising and allows us to formulate conditions for the source power to ignite detonation in certain system geometry.

  14. Development of an MRI rating scale for multiple brain regions: comparison with volumetrics and with voxel-based morphometry

    Energy Technology Data Exchange (ETDEWEB)

    Davies, R.R.; Williams, Guy B. [University of Cambridge, Department of Clinical Neurosciences, Cambridge (United Kingdom); Scahill, Victoria L.; Graham, Kim S. [Cardiff University, MRC Cognition and Brain Sciences Unit, Cambridge and Wales Institute of Cognitive Neuroscience, School of Psychology, Cardiff (United Kingdom); Graham, Andrew [University of Cambridge, Department of Clinical Neurosciences, Cambridge (United Kingdom); Cardiff University, MRC Cognition and Brain Sciences Unit, Cambridge and Wales Institute of Cognitive Neuroscience, School of Psychology, Cardiff (United Kingdom); Hodges, John R. [University of Cambridge, Department of Clinical Neurosciences, Cambridge (United Kingdom); Cardiff University, MRC Cognition and Brain Sciences Unit, Cambridge and Wales Institute of Cognitive Neuroscience, School of Psychology, Cardiff (United Kingdom); Prince of Wales Medical Research Institute, Cognitive Neurology, Sydney, NSW (Australia)

    2009-08-15

    We aimed to devise a rating method for key frontal and temporal brain regions validated against quantitative volumetric methods and applicable to a range of dementia syndromes. Four standardised coronal MR images from 36 subjects encompassing controls and cases with Alzheimer's disease (AD) and frontotemporal dementia (FTD) were used. After initial pilot studies, 15 regions produced good intra- and inter-rater reliability. We then validated the ratings against manual volumetry and voxel-based morphometry (VBM) and compared ratings across the subject groups. Validation against both manual volumetry (for both frontal and temporal lobes), and against whole brain VBM, showed good correlation with visual ratings for the majority of the brain regions. Comparison of rating scores across disease groups showed involvement of the anterior fusiform gyrus, anterior hippocampus and temporal pole in semantic dementia, while anterior cingulate and orbitofrontal regions were involved in behavioural variant FTD. This simple visual rating can be used as an alternative to highly technical methods of quantification, and may be superior when dealing with single cases or small groups. (orig.)

  15. Research of heat exchange rate of the pulsating heat pipe

    Directory of Open Access Journals (Sweden)

    Kravets V. Yu.

    2010-02-01

    Full Text Available Given article presents experimental research of heat transfer characteristics of the pulsating heat pipe (PHP which consists of seven coils with 1 mm inner diameter. Water was used as the heat carrier. PHP construction, measuring circuit and research technique are presented. It is shown that under PHP functioning there are two characteristic modes of operation, which can be distinguished by values of thermal resistance. PHP heat exchange features are disclosed.

  16. Effect of heating rate on the pyrolysis yields of rapeseed

    Energy Technology Data Exchange (ETDEWEB)

    Haykiri-Acma, H.; Yaman, S.; Kucukbayrak, S. [Chemical Engineering Department, Chemical and Metallurgical Engineering Faculty, Istanbul Technical University, Maslak, 34469 Istanbul (Turkey)

    2006-05-15

    The pyrolysis yields of rapeseed were investigated applying thermogravimetric analysis technique. The pyrolysis experiments were performed up to 1273K at heating rates of 5, 10, 20, 30, 40 and 50K/min in a dynamic nitrogen flow of 40cc/min. Effects of heating rate on the mass losses from the rapeseed were examined using the derivative thermogravimetric analysis profiles. This study showed that important differences on the pyrolytic behavior of rapeseed are observed when heating rate is changed. At the lower heating rates, the maximum rates of mass losses were relatively low. When the heating rate was increased, maximum rates of mass losses also increased. These variations were interpreted by the heterogeneous structure of biomass. Heating rates also concluded to affect the shape of the peaks. Increase in the heating rate shifted the main peak on the DTG profile to the lower temperatures. At low heating rates, there is probably resistance to mass or heat transfer inside the biomass particles. However, increase in heating rate overcame these restrictions, and led to higher conversion rates. The final pyrolysis temperatures were also affected from the variation of the heating rate. Activation energy values were first increased and then decreased depending on the heating rates. (author)

  17. In Vivo Three-Dimensional Velocity Vector Imaging and Volumetric Flow Rate Measurements

    DEFF Research Database (Denmark)

    Pihl, Michael Johannes; Stuart, Matthias Bo; Tomov, Borislav Gueorguiev

    2013-01-01

    scanner SARUS. Measurements are conducted on a carotid artery flow phantom from Danish Phantom Design, and 20 frames are acquired with a constant flow rate of 16.7±0.17 mL/s provided by a Shelley Medical Imaging Technologies CompuFlow 1000 system. The peak velocity magnitude in the vessel is found...

  18. Megahertz rate, volumetric imaging of bubble clouds in sonothrombolysis using a sparse hemispherical receiver array

    Science.gov (United States)

    Acconcia, Christopher N.; Jones, Ryan M.; Goertz, David E.; O’Reilly, Meaghan A.; Hynynen, Kullervo

    2017-09-01

    It is well established that high intensity focused ultrasound can be used to disintegrate clots. This approach has the potential to rapidly and noninvasively resolve clot causing occlusions in cardiovascular diseases such as deep vein thrombosis (DVT). However, lack of an appropriate treatment monitoring tool is currently a limiting factor in its widespread adoption. Here we conduct cavitation imaging with a large aperture, sparse hemispherical receiver array during sonothrombolysis with multi-cycle burst exposures (0.1 or 1 ms burst lengths) at 1.51 MHz. It was found that bubble cloud generation on imaging correlated with the locations of clot degradation, as identified with high frequency (30 MHz) ultrasound following exposures. 3D images could be formed at integration times as short as 1 µs, revealing the initiation and rapid development of cavitation clouds. Equating to megahertz frame rates, this is an order of magnitude faster than any other imaging technique available for in vivo application. Collectively, these results suggest that the development of a device to perform DVT therapy procedures would benefit greatly from the integration of receivers tailored to bubble activity imaging.

  19. SU-E-T-421: Feasibility Study of Volumetric Modulated Arc Therapy with Constant Dose Rate for Endometrial Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Yang, R; Wang, J [Peking University Third Hospital, Beijing, Beijing (China)

    2014-06-01

    Purpose: To investigate the feasibility, efficiency, and delivery accuracy of volumetric modulated arc therapy with constant dose rate (VMAT-CDR) for whole-pelvic radiotherapy (WPRT) of endometrial cancer. Methods: The nine-Field intensity-modulated radiotherapy (IMRT), VMAT with variable dose-rate (VMAT-VDR), and VMAT-CDR plans were created for 9 patients with endometrial cancer undergoing WPRT. The dose distribution of planning target volume (PTV), organs at risk (OARs), and normal tissue (NT) were compared. The monitor units (MUs) and treatment delivery time were also evaluated. For each VMAT-CDR plan, a dry Run was performed to assess the dosimetric accuracy with MatriXX from IBA. Results: Compared with IMRT, the VMAT-CDR plans delivered a slightly greater V20 of the bowel, bladder, pelvis bone, and NT, but significantly decreased the dose to the high-dose region of the rectum and pelvis bone. The MUs Decreased from 1105 with IMRT to 628 with VMAT-CDR. The delivery time also decreased from 9.5 to 3.2 minutes. The average gamma pass rate was 95.6% at the 3%/3 mm criteria with MatriXX pretreatment verification for 9 patients. Conclusion: VMAT-CDR can achieve comparable plan quality with significant shorter delivery time and smaller number of MUs compared with IMRT for patients with endometrial cancer undergoing WPRT. It can be accurately delivered and be an alternative to IMRT on the linear accelerator without VDR capability. This work is supported by the grant project, National Natural; Science Foundation of China (No. 81071237)

  20. Assessment of heating rate and non-uniform heating in domestic microwave ovens.

    Science.gov (United States)

    Pitchai, Krishnamoorthy; Birla, Sohan L; Jones, David; Subbiah, Jeyamkondan

    2012-01-01

    Due to the inherent nature of standing wave patterns of microwaves inside a domestic microwave oven cavity and varying dielectric properties of different food components, microwave heating produces non-uniform distribution of energy inside the food. Non-uniform heating is a major food safety concern in not-ready-to-eat (NRTE) microwaveable foods. In this study, we present a method for assessing heating rate and non-uniform heating in domestic microwave ovens. In this study a custom designed container was used to assess heating rate and non-uniform heating of a range of microwave ovens using a hedgehog of 30 T-type thermocouples. The mean and standard deviation of heating rate along the radial distance and sector of the container were measured and analyzed. The effect of the location of rings and sectors was analyzed using ANOVA to identify the best location for placing food on the turntable. The study suggested that the best location to place food in a microwave oven is not at the center but near the edge of the turntable assuming uniform heating is desired. The effect of rated power and cavity size on heating rate and non-uniform heating was also studied for a range of microwave ovens. As the rated power and cavity size increases, heating rate increases while non-uniform heating decreases. Sectors in the container also influenced heating rate (p heating rate. In general, sectors close to the magnetron tend to heat slightly faster than sectors away from the magnetron. However, the variation in heating rate among sectors was only 2 degrees C/min and considered not practically important. Overall heating performance such as mean heating rate and non-uniform heating did not significantly vary between the two replications that were performed 4 h apart. However, microwave ovens were inconsistent in producing the same heating patterns between the two replications that were performed 4 h apart.

  1. Impact of small MU/segment and dose rate on delivery accuracy of volumetric-modulated arc therapy (VMAT).

    Science.gov (United States)

    Huang, Long; Zhuang, Tingliang; Mastroianni, Anthony; Djemil, Toufik; Cui, Taoran; Xia, Ping

    2016-05-08

    Volumetric-modulated arc therapy (VMAT) plans may require more control points (or segments) than some of fixed-beam IMRT plans that are created with a limited number of segments. Increasing number of control points in a VMAT plan for a given prescription dose could create a large portion of the total number of segments with small number monitor units (MUs) per segment. The purpose of this study is to investigate the impact of the small number MU/segment on the delivery accuracy of VMAT delivered with various dose rates. Ten patient datasets were planned for hippocampus sparing for whole brain irradiation. For each dataset, two VMAT plans were created with maximum dose rates of 600 MU/min (the maximum field size of 21 × 40 cm2) and 1000 MU/min (the maximum field size of 15 × 15 cm2) for a daily dose of 3 Gy. Without reoptimization, the daily dose of these plans was purposely reduced to 1.5 Gy and 1.0 Gy while keeping the same total dose. Using the two dose rates and three different daily doses, six VMAT plans for each dataset were delivered to a physical phantom to investigate how the changes of dose rate and daily doses impact on delivery accuracy. Using the gamma index, we directly compared the delivered planar dose profiles with the reduced daily doses (1.5 Gy and 1.0 Gy) to the delivered planar dose at 3 Gy daily dose, delivered at dose rate of 600 MU/min and 1000 MU/min, respectively. The average numbers of segments with MU/segment ≤ 1 were 35 ± 8, 87 ± 6 for VMAT-600 1.5 Gy, VMAT-600 1 Gy plans, and 30 ± 7 and 42 ± 6 for VMAT-1000 1.5 Gy and VMAT-1000 1 Gy plans, respectively. When delivered at 600 MU/min dose rate, the average gamma index passing rates (1%/1 mm criteria) of comparing delivered 1.5 Gy VMAT planar dose profiles to 3.0 Gy VMAT delivered planar dose profiles was 98.28% ± 1.66%, and the average gamma index passing rate of comparing delivered 1.0 Gy VMAT planar dose to 3.0 Gy VMAT delivered planar dose was 83.75% ± 4.86%. If using 2%/2mm

  2. Heat exchangers selection, rating, and thermal design

    CERN Document Server

    Kakaç, Sadik; Pramuanjaroenkij, Anchasa

    2012-01-01

    Praise for the Bestselling Second EditionThe first edition of this work gathered in one place the essence of important information formerly scattered throughout the literature. The second edition adds the following new information: introductory material on heat transfer enhancement; an application of the Bell-Delaware method; new correlation for calculating heat transfer and friction coefficients for chevron-type plates; revision of many of the solved examples and the addition of several new ones.-MEMagazine

  3. HIGH HEATING RATES AFFECTS GREATLY THE INACTIVATION RATE OF ESCHERICHIA COLI

    Directory of Open Access Journals (Sweden)

    Juan Pablo Huertas

    2016-08-01

    Full Text Available Heat resistance of microorganisms can be affected by different influencing factors. Although the effect of heating rates has been scarcely explored by the scientific community, recent researches have unraveled its important effect on the thermal resistance of different species of vegetative bacteria. Typically heating rates described in the literature ranged from 1 to 20ºC/min but the impact of much higher heating rates is unclear. The aim of this research was to explore the effect of different heating rates, such as those currently achieved in the heat exchangers used in the food industry, on the heat resistance of Escherichia coli. A pilot plant tubular heat exchanger and a thermoresistometer Mastia were used for this purpose. Results showed that fast heating rates had a deep impact on the thermal resistance of E. coli. Heating rates between 20 and 50ºC/min were achieved in the heat exchanger, which were much slower than those around 20ºC/s achieved in the thermoresistometer. In all cases, these high heating rates led to higher inactivation than expected: in the heat exchanger, for all the experiments performed, when the observed inactivation had reached about seven log cycles, the predictions estimates about 1 log cycle of inactivation; in the thermoresistometer these differences between observed and predicted values were even more than ten times higher, from 4.07 log cycles observed to 0.34 predicted at a flow rate of 70 mL/min and a maximum heating rate of 14.7ºC/s. A quantification of the impact of the heating rates on the level of inactivation achieved was established. These results point out the important effect that the heating rate has on the thermal resistance of E. coli, with high heating rates resulting in an additional sensitization to heat and therefore an effective food safety strategy in terms of food processing.

  4. High Heating Rates Affect Greatly the Inactivation Rate of Escherichia coli

    Science.gov (United States)

    Huertas, Juan-Pablo; Aznar, Arantxa; Esnoz, Arturo; Fernández, Pablo S.; Iguaz, Asunción; Periago, Paula M.; Palop, Alfredo

    2016-01-01

    Heat resistance of microorganisms can be affected by different influencing factors. Although, the effect of heating rates has been scarcely explored by the scientific community, recent researches have unraveled its important effect on the thermal resistance of different species of vegetative bacteria. Typically heating rates described in the literature ranged from 1 to 20°C/min but the impact of much higher heating rates is unclear. The aim of this research was to explore the effect of different heating rates, such as those currently achieved in the heat exchangers used in the food industry, on the heat resistance of Escherichia coli. A pilot plant tubular heat exchanger and a thermoresistometer Mastia were used for this purpose. Results showed that fast heating rates had a deep impact on the thermal resistance of E. coli. Heating rates between 20 and 50°C/min were achieved in the heat exchanger, which were much slower than those around 20°C/s achieved in the thermoresistometer. In all cases, these high heating rates led to higher inactivation than expected: in the heat exchanger, for all the experiments performed, when the observed inactivation had reached about seven log cycles, the predictions estimated about 1 log cycle of inactivation; in the thermoresistometer these differences between observed and predicted values were even more than 10 times higher, from 4.07 log cycles observed to 0.34 predicted at a flow rate of 70 mL/min and a maximum heating rate of 14.7°C/s. A quantification of the impact of the heating rates on the level of inactivation achieved was established. These results point out the important effect that the heating rate has on the thermal resistance of E. coli, with high heating rates resulting in an additional sensitization to heat and therefore an effective food safety strategy in terms of food processing. PMID:27563300

  5. Characteristic thermal constant and dimensionless heating rate. The links to optimum heating rate in GC

    Science.gov (United States)

    Blumberg; Klee

    2000-09-01

    An initial step in the quest of deriving a generalized approach to optimization of a temperature program in gas chromatography is presented. Central to this is the introduction of a dimensionless heating rate, r. As a first step to defining r, a characteristic thermal constant, thetachar, defined as thetachar = -dT/dk at k = 1, where T and k are, respectively, column temperature and solute retention factor, is introduced and evaluated for our own experimental data and for thermodynamic data from the literature. It was determined that, for silicone stationary phases with a phase ratio of 250, thetachar ranged from about 23 degrees C for low molecular weight hydrocarbons such as dimethylpropane to about 45 degrees C for high molecular weight pesticides such as mirex. It was also found that, for a particular solute and a stationary phase type, a 2 orders of magnitude increase in the film thickness caused only about a 2-fold increase in the characteristic thermal constant. Using thetachar as a fundamental temperature unit in GC and void time as a fundamental time unit, a dimensionless heating rate is introduced and its potential utility for the evaluation of the separation-speed tradeoffs in a temperature-programmed GC is demonstrated.

  6. A reduced volumetric expansion factor plot

    Science.gov (United States)

    Hendricks, R. C.

    1979-01-01

    A reduced volumetric expansion factor plot has been constructed for simple fluids which is suitable for engineering computations in heat transfer. Volumetric expansion factors have been found useful in correlating heat transfer data over a wide range of operating conditions including liquids, gases and the near critical region.

  7. Studies on Microwave Heated Drying-rate Equations of Foods

    OpenAIRE

    1990-01-01

    In order to design various microwave heated drying apparatuses, we must take drying-rate equations which are based on simple drying-rate models. In a previous paper (KUBOTA, et al., 1990), we have studied a convenient microwave heated drying instrument, and studied the simple drying-rate equations of potato and so on by using the simple empirical rate equations that have been reported in previous papers (KUBOTA, 1979-1, 1979-2). In this paper, we studied the microwave drying rate of the const...

  8. A longitudinal observational study of brain atrophy rate reflecting four decades of multiple sclerosis: a comparison of serial 1D, 2D, and volumetric measurements from MRI images

    Energy Technology Data Exchange (ETDEWEB)

    Martola, Juha; Zhang, Yi; Aspelin, Peter; Kristoffersen Wiberg, Maria [Karolinska Institutet, Division of Radiology, Department of Clinical Science, Intervention, and Technology, Stockholm (Sweden); Bergstroem, Jakob [Karolinska Institutet, The Medical Statistics Unit, Department of Learning, Informatics, Management and Ethics (LIME), Stockholm (Sweden); Fredrikson, Sten; Stawiarz, Leszek; Hillert, Jan [Karolinska Institutet, Division of Neurology, Department of Clinical Neuroscience, Stockholm (Sweden); Flodmark, Olof; Lilja, Anders [Karolinska University Hospital, Department of Neuroradiology, Department of Clinical Neuroscience, Stockholm (Sweden); Ekbom, Anders [Karolinska Institutet, Clinical Epidemiology Unit, Stockholm (Sweden)

    2010-02-15

    Multiple sclerosis (MS) has a variable progression with an early onset of atrophy. Individual longitudinal radiological evaluations (over decades) are difficult to perform due to the limited availability of magnetic resonance imaging (MRI) in the past, patients lost in follow-up, and the continuous updating of scanners. We studied a cohort with widespread disease duration at baseline. The observed individual atrophy rates over time of 10 years represented four decades of disease span. Thirty-seven MS patients (age range 24-65 years with disease duration 1-33 years) were consecutively selected and evaluated with MRI at baseline 1995 and in 1996. They were followed up for a decade (mean of 9.25 years, range 7.3-10 years) up to 2003-2005. Brain parenchymal volume and volumes of the supratentorial ventricles were analyzed with semi-automated volumetric measurements at three time points (1995, 1996, and 2003-2005). Volumetric differences were found over shorter periods of time (1-7 months); however, differences vanished by the end of follow-up. A uniform longitudinal decrease in brain volume and increase in ventricle volumes were found. Frontal horn width (1D) correlated strongest to 3D measures. No statistical differences of atrophy rates between MS courses were found. Supratentorial ventricular volumes were associated with disability and this association persisted during follow-up. Despite variable clinical courses, the degenerative effects of MS progression expressed in brain atrophy seem to uniformly progress over longer periods of time. These volumetric changes can be detected using 1D and 2D measurements performed on a routine PACS workstation. (orig.)

  9. Critical heat removal rate through a hemispherical narrow gap

    Energy Technology Data Exchange (ETDEWEB)

    Park, R.J.; Ha, K.S.; Kang, K.H.; Kim, S.B.; Kim, H.D. [Severe Accident Research Project, Korea Atomic Energy Research Institute Yusong, P.O. Box 105, Daejeon (Korea); Jeong, J.H. [Chonan College of Foreign Studies, An-seo-Wong 150, Chun-an (Korea)

    2003-02-01

    An experimental study has been performed to investigate boiling mechanism and to estimate critical heat removal rate from a critical power through a hemispherical narrow gap using distilled water and Freon R-113. The distilled water data on the critical heat removal rate were compared with the R-113 data. The experimental results on the critical heat removal rate were also compared with the existing correlations, developed in flat plate, annuli, and spherical gaps. The test results have shown that a CCFL (Counter Current Flow Limitation) brings about local dryout and finally global dryout in the hemispherical gap thickness of 0.5, 1.0, and 2.0 mm. The boiling mechanism in a hemispherical gap thickness of 5.0 mm is the combination of the CCFL and the pool boiling condition. An increase in gap thickness of 10.0 mm leads to the pool boiling condition rather than the CCFL. Increases in the gap thickness and pressure lead to increase in critical heat removal rate, but the pressure effect on the critical heat removal rate was found to be much milder than the predictions by flat plate and annuli gaps. The measured critical heat removal rate using the R-113 in hemispherical narrow gap thickness of 1.0 and 2.0 mm are 51.5%, 44.5% lower than that using the distilled water due to the lower boiling point and the bubble size, which is different from the pool boiling condition of approximately 14.8%. The measured critical heat removal rate using the R-113 in a gap thickness of 5 mm is 21.6% lower than that using distilled water, which approaches to the pool boiling condition. (orig.)

  10. r-PROCESS LANTHANIDE PRODUCTION AND HEATING RATES IN KILONOVAE

    Energy Technology Data Exchange (ETDEWEB)

    Lippuner, Jonas; Roberts, Luke F., E-mail: jlippuner@tapir.caltech.edu [TAPIR, Walter Burke Institute for Theoretical Physics, California Institute of Technology, MC 350-17, 1200 E California Boulevard, Pasadena CA 91125 (United States)

    2015-12-20

    r-process nucleosynthesis in material ejected during neutron star mergers may lead to radioactively powered transients called kilonovae. The timescale and peak luminosity of these transients depend on the composition of the ejecta, which determines the local heating rate from nuclear decays and the opacity. Kasen et al. and Tanaka and Hotokezaka pointed out that lanthanides can drastically increase the opacity in these outflows. We use the new general-purpose nuclear reaction network SkyNet to carry out a parameter study of r-process nucleosynthesis for a range of initial electron fractions Y{sub e}, initial specific entropies s, and expansion timescales τ. We find that the ejecta is lanthanide-free for Y{sub e} ≳ 0.22−0.30, depending on s and τ. The heating rate is insensitive to s and τ, but certain, larger values of Y{sub e} lead to reduced heating rates, due to individual nuclides dominating the heating. We calculate approximate light curves with a simplified gray radiative transport scheme. The light curves peak at about a day (week) in the lanthanide-free (-rich) cases. The heating rate does not change much as the ejecta becomes lanthanide-free with increasing Y{sub e}, but the light-curve peak becomes about an order of magnitude brighter because it peaks much earlier when the heating rate is larger. We also provide parametric fits for the heating rates between 0.1 and 100 days, and we provide a simple fit in Y{sub e}, s, and τ to estimate whether or not the ejecta is lanthanide-rich.

  11. Inverse bremsstrahlung heating rate for dense plasmas in laser fields

    Energy Technology Data Exchange (ETDEWEB)

    Dey, R. [D-203, Samruddhi Residency, Motera, Ahmedabad-380009, Gujarat (India); Roy, A. C. [School of Mathematical Sciences, Ramakrishna Mission Vivekananda University, Belur Math 711202, West Bengal (India)

    2013-07-15

    We report a theoretical analysis of inverse bremsstrahlung heating rate in the eikonal approximation. The present analysis is performed for a dense plasma using the screened electron-ion interaction potential for the ion charge state Z{sub i} = 1 and for both the weak and strong plasma screening cases. We have also compared the eikonal results with the first Born approximation (FBA) [M. Moll et al., New J. Phys. 14, 065010 (2012)] calculation. We find that the magnitudes of inverse bremsstrahlung heating rate within the eikonal approximation (EA) are larger than the FBA values in the weak screening case (κ = 0.03 a.u.) in a wide range of field strength for three different initial electron momenta (2, 3, and 4 a.u.). But for strong screening case (κ = 0.3 a.u.), the heating rates predicted by the two approximations do not differ much after reaching their maximum values. Furthermore, the individual contribution of photoemission and photoabsorption processes to heating rate is analysed for both the weak and strong screening cases. We find that the single photoemission and photoabsorption rates are the same throughout the field strength while the multiphoton absorption process dominates over the multiphoton emission process beyond the field strength ≈ 4×10{sup 8} V/cm. The present study of the dependence of heating rate on the screening parameter ranging from 0.01 to 20 shows that whereas the heating rate predicted by the EA is greater than the FBA up to the screening parameter κ = 0.3 a.u., the two approximation methods yield results which are nearly identical beyond the above value.

  12. Experimental Investigation of Heat transfer rate of Nano fluids using a Shell and Tube Heat exchanger

    Science.gov (United States)

    SIVA ESWARA RAO, M.; SREERAMULU, DOWLURU; ASIRI NAIDU, D.

    2016-09-01

    Nano fluids are used for increasing thermal properties in heat transfer equipment like heat exchangers, radiators etc. This paper investigates the heat transfer rate of Nano fluids using a shell and tube heat exchanger in single and multi tubes under turbulent flow condition by a forced convection mode. Alumina Nanoparticles are prepared by using Sol-Gel method. Heat transfer rate increases with decreasing particle size. In this experiment Alumina Nano particles of about 22 nm diameter used. Alumina Nano fluids are prepared with different concentrations of Alumina particles (0.13%, 0.27%, 0.4%, and 0.53%) with water as a base fluid using ultra-sonicator. Experiment have been conducted on shell and tube heat exchanger for the above concentrations on parallel and counter flow conditions by keeping constant inlet temperatures and mass flow rate. The result shows that the heat transfer rate is good compared to conventional fluids. The properties of Nano fluids and non-dimensional numbers have been calculated.

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

    Energy Technology Data Exchange (ETDEWEB)

    ANDREWS,J.W.

    2003-05-28

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

  14. HEATING RATE SCALING OF TURBULENCE IN THE PROTON KINETIC REGIME

    Energy Technology Data Exchange (ETDEWEB)

    Vasquez, Bernard J., E-mail: bernie.vasquez@unh.edu [Physics Department and Space Science Center, University of New Hampshire, Durham, NH 03824 (United States)

    2015-06-10

    Three-dimensional numerical hybrid simulations with particle protons and quasi-neutralizing, fluid electrons are conducted for a freely decaying turbulence. The main results are obtained from a series of runs as a function of the initial total rms fluctuation amplitude. In the turbulent phase and at a corresponding nonlinear time dependent on the amplitude, the scaling of the proton perpendicular heating rate is examined as a function of the spectral value of the electron bulk perpendicular speed integrated in wavenumbers about the inverse thermal proton gyroradius. The perpendicular direction is relative to the background magnetic field. The obtained spectral value is normalized to the proton thermal speed and ranges from 0.06 to 0.16. The scaling of the perpendicular heating rate with this spectral value is fitted with a power law, which has an index of −3.3 ± 0.2. The fit is consistent with the scaling of the total heating rate as a function of total rms amplitude, which has an index of −3.06 ± 0.12. The power-law index is near the turbulent hydrodynamic-like prediction for the energy cascade rate as a function of amplitude. The heating rate, then, obeys a power law with amplitude or spectral value regardless of whether that quantity is evaluated at large scales or at the proton gyroradius scales.

  15. Heating rate dependence of anatase to rutile transformation

    Directory of Open Access Journals (Sweden)

    Pietro Galizia

    2016-12-01

    Full Text Available Commercial titania powders were calcined in order to investigate the influence of the heating history on the thermally stable phase (rutile. Temperatures from 620 to 700 °C and heating rates from 50 to 300 °C/h were used in order to evaluate their influence on the kinetics of transformation and microstructure evolution. The quantitative analysis of anatase-rutile mixtures based on X-ray diffraction intensities was performed. The results were plotted as cumulative transformation rate vs. cumulative coarsening rate in order to address the heating history of the anatase to rutile transformation. As the main result it was found that the amount of anatase transformed into rutile increases with increasing heating rate at fixed soaking time and temperature of calcination. Through linear extrapolation of experimental data obtained from the calcined commercial titania Degussa P25, it was found that 83 nm for the rutile crystallite size is the lowest limit needed for getting 100% of rutile powders. A substantial improvement in the anatase to rutile kinetic transformation was achieved after pressing the starting powders in order to exploit the interface nucleation.

  16. Flash Heating of Crustal Rocks at Seismic Slip Rates

    Science.gov (United States)

    Goldsby, D. L.; Spagnuolo, E.; Smith, S. A.; Beeler, N. M.; Tullis, T. E.; Di Toro, G.; Nielsen, S. B.

    2012-12-01

    Recent experiments have demonstrated that rocks undergo extreme frictional weakening at near-earthquake slip rates due to the thermal degradation of the strength, or even melting, of microscopic asperity contacts on their sliding surfaces (Goldsby and Tullis, 2012). These previous experiments, conducted at constant normal stress and slip rates of up to ~0.4 m/s, revealed a 1/V dependence of friction on slip rate above a characteristic weakening velocity, Vw, in accord with theories of flash heating (e.g., Rice, 2006). The weakening velocity obtains values of ~0.1 m/s for many crustal silicate rocks (Goldsby and Tullis, 2012). Here we test two further predictions of flash-heating theory - that the degree of weakening saturates at slip rates approaching 1 m/s, and that the weakening behavior due to flash heating is independent of normal stress - by testing samples at slip rates of up to 1 m/s at different normal stresses. Experiments were conducted in a 1-atm, high-velocity friction apparatus at the Istituto Nazionale di Geofisica e Vulcanologia in Rome. A sample consisted of a pair of hollow cylinders of Westerly granite or Frederick diabase subjected to a nominally constant normal stress of from 1 to 30 MPa and subjected to a variety of rate-stepping sequences. Data were acquired at rates of up to 1 MHz. As predicted, the experiments demonstrate that the degree of weakening due to flash heating saturates at slip rates approaching 1 m/s; in a few cases, friction even increases slightly with increasing slip rate near 1 m/s. The experiments also demonstrate that, within the scatter of the data, the value of Vw and the friction coefficient in the weakened state is independent of normal stress, the expected result if average contact sizes and contact stresses are independent of normal stress. The data thus further corroborate existing theories and experimental data for flash heating, allowing for a more reliable determination of the conditions under which flash heating

  17. Three-dimensional transient mathematical model to predict the heat transfer rate of a heat pipe

    Directory of Open Access Journals (Sweden)

    S Boothaisong

    2015-02-01

    Full Text Available A three-dimensional model was developed to simulate the heat transfer rate on a heat pipe in a transient condition. This article presents the details of a calculation domain consisting of a wall, a wick, and a vapor core. The governing equation based on the shape of the pipe was numerically simulated using the finite element method. The developed three-dimensional model attempted to predict the transient temperature, the velocity, and the heat transfer rate profiles at any domain. The values obtained from the model calculation were then compared with the actual results from the experiments. The experiment showed that the time required to attain a steady state (where transient temperature is constant was reasonably consistent with the model. The working fluid r134a (tetrafluoroethane was the quickest to reach the steady state and transferred the greatest amount of heat.

  18. r-Process Lanthanide Production and Heating Rates in Kilonovae

    CERN Document Server

    Lippuner, Jonas

    2015-01-01

    r-Process nucleosynthesis in material ejected during neutron star mergers may lead to radioactively powered transients called kilonovae. The timescale and peak luminosity of these transients depend on the composition of the material after nuclear burning ceases, which determines the local heating rate from nuclear decays and the opacity. Kasen et al. (2013, ApJ, 774, 25) and Tanaka & Hotokezaka (2013, ApJ, 775, 113) pointed out that lanthanides can drastically increase the opacity in these outflows. We use the new general-purpose nuclear reaction network SkyNet to carry out a parameter study of r-process nucleosynthesis for a range of initial electron fractions $Y_e$, initial specific entropies $s$, and expansion timescales $\\tau$. We find that the ejecta is lanthanide-free for $Y_e \\gtrsim 0.22 - 0.30$, depending on $s$ and $\\tau$. The heating rate is insensitive to $s$ and $\\tau$, but certain, larger values of $Y_e$ lead to reduced heating rates, due to individual nuclides dominating the heating. With a...

  19. Two features of the uniaxial compression of a glassy epoxy resin: the yield stress rate-dependence and the volumetric instability

    Science.gov (United States)

    Bardella, Lorenzo; Belleri, Andrea

    2011-08-01

    We report the results of uniaxial compressive tests on a DGEBA epoxy resin at room temperature, well below its glass transition. We first focus on the strength, defined as the stress value corresponding to either a maximum or a flattening of the stress-strain curve, which, for this polymer, may be taken to be coincident with the yield stress, as often assumed for many thermosets. Within the strain rate range (1.E-6 s-1, 2.E-3 s-1) we confirm the linear trend relating the logarithm of the strain rate to the yield stress, as already been observed by other investigators even for the same epoxy resin; instead, at strain rates below dot{\\varepsilon} 0 ≈ 1.E{-}6 s^{-1}, we found a negligible rate-dependence, as our data indicate a lowest limit of the yield stress, of about 87 MPa. On the basis of these results, we propose how to extend to the viscoplastic regime of deformation a nonlinear viscoelastic model previously put forward. Secondarily, within the viscoelastic range, at a stress level significantly lower than the yield stress, our measurements show a mild volumetric instability, allowed by the free lateral expansion, not ascribable to any macroscopic structural effect; such a behaviour has never been reported in the literature, to the best of our knowledge.

  20. Standby Rates for Combined Heat and Power Systems

    Energy Technology Data Exchange (ETDEWEB)

    Sedano, Richard [Regulatory Assistance Partnership; Selecky, James [Brubaker & Associates, Inc.; Iverson, Kathryn [Brubaker & Associates, Inc.; Al-Jabir, Ali [Brubaker & Associates, Inc.

    2014-02-01

    Improvements in technology, low natural gas prices, and more flexible and positive attitudes in government and utilities are making distributed generation more viable. With more distributed generation, notably combined heat and power, comes an increase in the importance of standby rates, the cost of services utilities provide when customer generation is not operating or is insufficient to meet full load. This work looks at existing utility standby tariffs in five states. It uses these existing rates and terms to showcase practices that demonstrate a sound application of regulatory principles and ones that do not. The paper also addresses areas for improvement in standby rates.

  1. Resistive Wall Heating of the Undulator in High Repetition Rate

    Energy Technology Data Exchange (ETDEWEB)

    Qiang, J; Corlett, J; Emma, P; Wu, J

    2012-05-20

    In next generation high repetition rate FELs, beam energy loss due to resistive wall wakefields will produce significant amount of heat. The heat load for a superconducting undulator (operating at low temperature), must be removed and will be expensive to remove. In this paper, we study this effect in an undulator proposed for a Next Generation Light Source (NGLS) at LBNL. We benchmark our calculations with measurements at the LCLS and carry out detailed parameter studies using beam from a start-to-end simulation. Our preliminarym results suggest that the heat load in the undulator is about 2 W/m or lower with an aperture size of 6 mm for nominal NGLS preliminary design parameters.

  2. Heat transfer and heating rate of food stuffs in commercial shop ovens

    Indian Academy of Sciences (India)

    P Navaneethakrishnan; P S S Srinivasan; S Dhandapani

    2007-10-01

    The CFD analysis of flow and temperature distribution in heating ovens used in bakery shop, to keep the foodstuffs warm, is attempted using finite element technique. The oven is modelled as a two-dimensional steady state natural convection heat transfer problem. Effects of heater location and total heat input on temperature uniformity of foodstuffs are studied. Placing the heater at the bottom of the oven improves the air circulation rate by 17 times and 10 times than that at the top and side of the oven. But the top location provides better uniformity in foodstuff temperature than the other cases. Side location is not preferable. In the present ovens, the heating elements are located at the top. The analysis shows that if heaters are located at the bottom along with additional flow guidance arrangements, energy efficient oven configuration can be obtained.

  3. Volumetric Heat Generation and Consequence Raise in Temperature Due to Absorption of Neutrons from Thermal up to 14.9 MeV Energies

    CERN Document Server

    Massoud, E

    2003-01-01

    In this work, the heat generation rate and the consequence rise in temperature due to absorption of all neutrons from thermal energies (E<0.025) up to 14.9 MeV in water, paraffin wax, ordinary concrete and heavy concrete and heavy concrete as some selected hydrogenous materials are investigated. The neutron flux distributions are calculated by both ANISN-code and three group method in which the fast neutrons are expressed by the removal cross section concept while the other two groups (epithermal and thermal) are treated by the diffusion equation. The heat generation can be calculated from the neutron macroscopic absorption of each material or mixture multiplied by the corresponding neutron fluxes. The rise in temperature is then calculated by using both of the heat generation and the thermal conductivity of the selected materials. Some results are compared with the available experimental and theoretical data and a good agreement is achieved.

  4. Pyrolysis kinetics of bagasse at high heating rates

    Energy Technology Data Exchange (ETDEWEB)

    Stubington, J.F.; Aiman, S. (University of New South Wales, Kensington, NSW (Australia). Dept. of Fuel Technology)

    The rate of pyrolysis of bagasse was studied at high heating rates (200-10,000 [degree]C/s) to obtain engineering data for incorporation into computational fluid dynamic models of bagasse ignition and combustion in suspension-fired and swirl burners. Experiments were performed using an electrically-heated grid under a nitrogen atmosphere at atmosphere pressure. Yields of char, tar, individual gas components, and water were measured as a function of peak temperature, for ranges of heating rate, residence time at peak temperature, and particle size. At higher peak temperatures, significant tar cracking occurred so that tar yields passed through a maximum as peak temperature increased. For dry bagasse, this tar cracking produced gases with no change in char yield, suggesting that it occurred external to the particle. Moisture in the atmosphere increased the tar cracking in the vapor phase outside the bagasse particle producing more gases but did not affect the char yield. However, moisture in the bagasse reduced the char yield and further enhanced the tar cracking reactions, producing even more gases (predominantly carbon monoxide). These results suggested an interaction between water vapor and the tar cracking reactions. For the short residence times appropriate to such burners, a single, first-order reaction model gave the best fit to the total weight loss for the ranges of heating rate and particle sizes studied. However, the first-order kinetic parameters fitted to primary tar production were recommended for modeling purposes because the total weight loss included significant yields of noncombustible water and carbon dioxide. Different ultimate primary tar yields were recommended to fit the dry and wet bagasse pyrolysis results. No chemical significance should be attributed to the kinetic parameters, which were determined to provide the simplest and best fit to the pyrolysis data. 19 refs., 15 figs., 5 tabs.

  5. Volumetric Virtual Environments

    Institute of Scientific and Technical Information of China (English)

    HE Taosong

    2000-01-01

    Driven by fast development of both virtual reality and volume visualization, we discuss some critical techniques towards building a volumetric VR system, specifically the modeling, rendering, and manipulations of a volumetric scene.Techniques such as voxel-based object simplification, accelerated volume rendering,fast stereo volume rendering, and volumetric "collision detection" are introduced and improved, with the idea of demonstrating the possibilities and potential benefits of incorporating volumetric models into VR systems.

  6. Particle loading rates for HVAC filters, heat exchangers, and ducts.

    Science.gov (United States)

    Waring, M S; Siegel, J A

    2008-06-01

    The rate at which airborne particulate matter deposits onto heating, ventilation, and air-conditioning (HVAC) components is important from both indoor air quality (IAQ) and energy perspectives. This modeling study predicts size-resolved particle mass loading rates for residential and commercial filters, heat exchangers (i.e. coils), and supply and return ducts. A parametric analysis evaluated the impact of different outdoor particle distributions, indoor emission sources, HVAC airflows, filtration efficiencies, coils, and duct system complexities. The median predicted residential and commercial loading rates were 2.97 and 130 g/m(2) month for the filter loading rates, 0.756 and 4.35 g/m(2) month for the coil loading rates, 0.0051 and 1.00 g/month for the supply duct loading rates, and 0.262 g/month for the commercial return duct loading rates. Loading rates are more dependent on outdoor particle distributions, indoor sources, HVAC operation strategy, and filtration than other considered parameters. The results presented herein, once validated, can be used to estimate filter changing and coil cleaning schedules, energy implications of filter and coil loading, and IAQ impacts associated with deposited particles. The results in this paper suggest important factors that lead to particle deposition on HVAC components in residential and commercial buildings. This knowledge informs the development and comparison of control strategies to limit particle deposition. The predicted mass loading rates allow for the assessment of pressure drop and indoor air quality consequences that result from particle mass loading onto HVAC system components.

  7. On-line measurement of heat of combustion

    Science.gov (United States)

    Chaturvedi, S. K.; Chegini, H.

    1988-01-01

    An experimental method for an on-line measurement of heat of combustion of a gaseous hydrocarbon fuel mixture of unknown composition is developed. It involves combustion of a test gas with a known quantity of air to achieve a predetermined oxygen concentration level in the combustion products. This is accomplished by a feedback controller which maintains the gas volumetric flow rate at a level consistent with the desired oxygen concentration in the products. The heat of combustion is determined from a known correlation with the gas volumetric flow rate. An on-line microcomputer accesses the gas volumetric flow data, and displays the heat of combustion values at desired time intervals.

  8. Analysis of Water Recovery Rate from the Heat Melt Compactor

    Science.gov (United States)

    Balasubramaniam, R.; Hegde, U.; Gokoglu, S.

    2013-01-01

    any remaining free water in the trash by evaporation. The temperature settings of the heated surfaces are usually kept above the saturation temperature of water but below the melting temperature of the plastic in the waste during this step to avoid any encapsulation of wet trash which would reduce the amount of recovered water by blocking the vapor escape. In this paper, we analyze the water recovery rate during Phase B where the trash is heated and water leaves the waste chamber as vapor, for operation of the HMC in reduced gravity. We pursue a quasi-one-dimensional model with and without sidewall heating to determine the water recovery rate and the trash drying time. The influences of the trash thermal properties, the amount of water loading, and the distribution of the water in the trash on the water recovery rates are determined.

  9. Solar Flux Deposition And Heating Rates In Jupiter's Atmosphere

    Science.gov (United States)

    Perez-Hoyos, Santiago; Sánchez-Lavega, A.

    2009-09-01

    We discuss here the solar downward net flux in the 0.25 - 2.5 µm range in the atmosphere of Jupiter and the associated heating rates under a number of vertical cloud structure scenarios focusing in the effect of clouds and hazes. Our numerical model is based in the doubling-adding technique to solve the radiative transfer equation and it includes gas absorption by CH4, NH3 and H2, in addition to Rayleigh scattering by a mixture of H2 plus He. Four paradigmatic Jovian regions have been considered (hot-spots, belts, zones and Polar Regions). The hot-spots are the most transparent regions with downward net fluxes of 2.5±0.5 Wm-2 at the 6 bar level. The maximum solar heating is 0.04±0.01 K/day and occurs above 1 bar. Belts and zones characterization result in a maximum net downward flux of 0.5 Wm-2 at 2 bar and 0.015 Wm-2 at 6 bar. Heating is concentrated in the stratospheric and tropospheric hazes. Finally, Polar Regions are also explored and the results point to a considerable stratospheric heating of 0.04±0.02 K/day. In all, these calculations suggest that the role of the direct solar forcing in the Jovian atmospheric dynamics is limited to the upper 1 - 2 bar of the atmosphere except in the hot-spot areas. Acknowledgments: This work has been funded by Spanish MEC AYA2006-07735 with FEDER support and Grupos Gobierno Vasco IT-464-07.

  10. Maximum orbit plane change with heat-transfer-rate considerations

    Science.gov (United States)

    Lee, J. Y.; Hull, D. G.

    1990-01-01

    Two aerodynamic maneuvers are considered for maximizing the plane change of a circular orbit: gliding flight with a maximum thrust segment to regain lost energy (aeroglide) and constant altitude cruise with the thrust being used to cancel the drag and maintain a high energy level (aerocruise). In both cases, the stagnation heating rate is limited. For aeroglide, the controls are the angle of attack, the bank angle, the time at which the burn begins, and the length of the burn. For aerocruise, the maneuver is divided into three segments: descent, cruise, and ascent. During descent the thrust is zero, and the controls are the angle of attack and the bank angle. During cruise, the only control is the assumed-constant angle of attack. During ascent, a maximum thrust segment is used to restore lost energy, and the controls are the angle of attack and bank angle. The optimization problems are solved with a nonlinear programming code known as GRG2. Numerical results for the Maneuverable Re-entry Research Vehicle with a heating-rate limit of 100 Btu/ft(2)-s show that aerocruise gives a maximum plane change of 2 deg, which is only 1 deg larger than that of aeroglide. On the other hand, even though aerocruise requires two thrust levels, the cruise characteristics of constant altitude, velocity, thrust, and angle of attack are easy to control.

  11. The pyrolysis kinetics of bagasse at low heating rates

    Energy Technology Data Exchange (ETDEWEB)

    Aiman, S.; Stubington, J.F. (New South Wales Univ., Kensington, NSW (Australia))

    1993-01-01

    Thermogravimetric Analysis (TGA) was used to study the thermal degradation of wet and dry bagasse at low heating rates (5 to 50[sup o]C min[sup -1]) under a nitrogen atmosphere. For engineering purposes, it was found that a single first-order reaction gave the simplest and best fit to the rapid pyrolysis zone between 195 and 395[sup o]C, with an activation energy of 93.2 kJ mol[sup -1] and pre-exponential factor of 4.33 x 10[sup 4]s[sup -1]. These values have no chemical significance, but have been derived for use in modelling studies of the ignition and combustion of bagasse. Sample moisture content up to 18% by weight had no effect on the degradation, because moisture evaporation was complete before pyrolysis commenced at these low heating rates. The choice of the final mass from the TGA curve significantly affected the deduced kinetic parameters. The final sample mass at the end of the rapid pyrolysis zone was 26.2% of the dry sample mass. (author)

  12. Integration and software for thermal test of heat rate sensors

    Science.gov (United States)

    Wojciechowski, C. J.; Shrider, K. R.

    1982-04-01

    A minicomputer controlled radiant test facility is described which was developed and calibrated in an effort to verify analytical thermal models of instrumentation islands installed aboard the space shuttle external tank to measure thermal flight parameters during ascent. Software was provided for the facility as well as for development tests on the SRB actuator tail stock. Additional testing was conducted with the test facility to determine the temperature and heat flux rate and loads required to effect a change of color in the ET tank external paint. This requirement resulted from the review of photographs taken of the ET at separation from the orbiter which showed that 75% of the external tank paint coating had not changed color from its original white color. The paint on the remaining 25% of the tank was either brown or black, indicating that it had degraded due to heating or that the spray on form insulation had receded in these areas. The operational capability of the facility as well as the various tests which were conducted and their results are discussed.

  13. The Optimum Plate to Plate Spacing for Maximum Heat Transfer Rate from a Flat Plate Type Heat Exchanger

    Science.gov (United States)

    Ambarita, Himsar; Kishinami, Koki; Daimaruya, Mashashi; Tokura, Ikuo; Kawai, Hideki; Suzuki, Jun; Kobiyama, Mashayosi; Ginting, Armansyah

    The present paper is a study on the optimum plate to plate spacing for maximum heat transfer rate from a flat plate type heat exchanger. The heat exchanger consists of a number of parallel flat plates. The working fluids are flowed at the same operational conditions, either fixed pressure head or fixed fan power input. Parallel and counter flow directions of the working fluids were considered. While the volume of the heat exchanger is kept constant, plate number was varied. Hence, the spacing between plates as well as heat transfer rate will vary and there exists a maximum heat transfer rate. The objective of this paper is to seek the optimum plate to plate spacing for maximum heat transfer rate. In order to solve the problem, analytical and numerical solutions have been carried out. In the analytical solution, the correlations of the optimum plate to plate spacing as a function of the non-dimensional parameters were developed. Furthermore, the numerical simulation is carried out to evaluate the correlations. The results show that the optimum plate to plate spacing for a counter flow heat exchanger is smaller than parallel flow ones. On the other hand, the maximum heat transfer rate for a counter flow heat exchanger is bigger than parallel flow ones.

  14. Cerebral volumetric abnormalities in Neurofibromatosis type 1: associations with parent ratings of social and attention problems, executive dysfunction, and autistic mannerisms

    NARCIS (Netherlands)

    Huijbregts, S.C.; Loitfelder, M.; Rombouts, S.A.R.B.; Swaab, H.; Verbist, B.M.; Arkink, E.B.; Buchem, M.A. van; Veer, I.M.

    2015-01-01

    Neurofibromatosis type 1 (NF1) is a single-gene neurodevelopmental disorder, in which social and cognitive problems are highly prevalent. Several commonly observed central nervous system (CNS) abnormalities in NF1 might underlie these social and cognitive problems. Cerebral volumetric abnormalities

  15. Research of Heating Rates Influence on Layer Coal Gasification of Krasnogorsky And Borodinsky Coal Deposit

    Directory of Open Access Journals (Sweden)

    Jankovskiy Stanislav

    2015-01-01

    Full Text Available Experimental research of heating rate influence on coal samples gasification process of Krasnogorsky and Borodinsky coal deposit ranks A and 2B was done to define optimal heating mode in high intensification of dispersal of inflammable gases conditions. Abundance ratio of carbon monoxide and nitrogen monoxide, water vapor, carbon dioxide at four values of heating rate within the range of 5 to 30 K/min. with further definition of optimal heating rate of coals was stated.

  16. Dissolution and Precipitation Behaviour during Continuous Heating of Al–Mg–Si Alloys in a Wide Range of Heating Rates

    Directory of Open Access Journals (Sweden)

    Julia Osten

    2015-05-01

    Full Text Available In the present study, the dissolution and precipitation behaviour of four different aluminium alloys (EN AW-6005A, EN AW-6082, EN AW-6016, and EN AW-6181 in four different initial heat treatment conditions (T4, T6, overaged, and soft annealed was investigated during heating in a wide dynamic range. Differential scanning calorimetry (DSC was used to record heating curves between 20 and 600 °C. Heating rates were studied from 0.01 K/s to 5 K/s. We paid particular attention to control baseline stability, generating flat baselines and allowing accurate quantitative evaluation of the resulting DSC curves. As the heating rate increases, the individual dissolution and precipitation reactions shift to higher temperatures. The reactions during heating are significantly superimposed and partially run simultaneously. In addition, precipitation and dissolution reactions are increasingly suppressed as the heating rate increases, whereby exothermic precipitation reactions are suppressed earlier than endothermic dissolution reactions. Integrating the heating curves allowed the enthalpy levels of the different initial microstructural conditions to be quantified. Referring to time–temperature–austenitisation diagrams for steels, continuous heating dissolution diagrams for aluminium alloys were constructed to summarise the results in graphical form. These diagrams may support process optimisation in heat treatment shops.

  17. 40 CFR 75.36 - Missing data procedures for heat input rate determinations.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 16 2010-07-01 2010-07-01 false Missing data procedures for heat input... (CONTINUED) AIR PROGRAMS (CONTINUED) CONTINUOUS EMISSION MONITORING Missing Data Substitution Procedures § 75.36 Missing data procedures for heat input rate determinations. (a) When hourly heat input rate...

  18. Heat transfer intensification by increasing vapor flow rate in flat heat pipes

    Science.gov (United States)

    Sprinceana, Silviu; Mihai, Ioan; Beniuga, Marius; Suciu, Cornel

    2015-02-01

    Flat heat pipes have various technical applications, one of the most important being the cooling of electronic components[9]. Their continuous development is due to the fact that these devices permit heat transfer without external energetic contribution. The practical exploitation of flat heat pipes however is limited by the fact that dissipated power can only reach a few hundred watts. The present paper aims to advance a new method for the intensification of convective heat transfer. A centrifugal mini impeller, driven by a turntable which incorporates four permanent magnets was designed. These magnets are put in motion by another rotor, which in its turn includes two permanent magnets and is driven by a mini electrical motor. Rotation of the centrifugal blades generates speed and pressure increase of the cooling agent brought to vapor state within the flat micro heat pipe. It's well known that the liquid suffers biphasic transformations during heat transfer inside the heat pipe. Over the hotspot (the heat source being the electronic component) generated at one end of the heat pipe, convective heat transfer occurs, leading to sudden vaporization of the liquid. Pressures generated by newly formed vapors push them towards the opposite end of the flat heat pipe, where a finned mini heat sink is usually placed. The mini-heat exchanger is air-cooled, thus creating a cold spot, where vapors condensate. The proposed method contributes to vapor flow intensification by increasing their transport speed and thus leading to more intense cooling of the heat pipe.

  19. An algorithm for the kinetics of tire pyrolysis under different heating rates.

    Science.gov (United States)

    Quek, Augustine; Balasubramanian, Rajashekhar

    2009-07-15

    Tires exhibit different kinetic behaviors when pyrolyzed under different heating rates. A new algorithm has been developed to investigate pyrolysis behavior of scrap tires. The algorithm includes heat and mass transfer equations to account for the different extents of thermal lag as the tire is heated at different heating rates. The algorithm uses an iterative approach to fit model equations to experimental data to obtain quantitative values of kinetic parameters. These parameters describe the pyrolysis process well, with good agreement (r(2)>0.96) between the model and experimental data when the model is applied to three different brands of automobile tires heated under five different heating rates in a pure nitrogen atmosphere. The model agrees with other researchers' results that frequencies factors increased and time constants decreased with increasing heating rates. The model also shows the change in the behavior of individual tire components when the heating rates are increased above 30 K min(-1). This result indicates that heating rates, rather than temperature, can significantly affect pyrolysis reactions. This algorithm is simple in structure and yet accurate in describing tire pyrolysis under a wide range of heating rates (10-50 K min(-1)). It improves our understanding of the tire pyrolysis process by showing the relationship between the heating rate and the many components in a tire that depolymerize as parallel reactions.

  20. Thermal effusivity measurement based on analysis of 3D heat flow by modulated spot heating using a phase lag matrix with a combination of thermal effusivity and volumetric heat capacity

    Science.gov (United States)

    Ohta, Hiromichi; Hatori, Kimihito; Matsui, Genzou; Yagi, Takashi; Miyake, Shugo; Okamura, Takeo; Endoh, Ryo; Okada, Ryo; Morishita, Keisuke; Yokoyama, Shinichiro; Taguchi, Kohei; Kato, Hideyuki

    2016-11-01

    The study goal was to establish a standard industrial procedure for the measurement of thermal effusivity by a thermal microscope (TM), using a periodic heating method with a thermoreflectance (TR) technique. To accomplish this goal, a working group was organized that included four research institutes. Each institute followed the same procedure: a molybdenum (Mo) film was sputtered on the surface of Pyrex, yttria-stabilized zirconia (YSZ), alumina (Al2O3), Germanium (Ge), and silicon (Si) samples, and then the phase lag of the laser intensity modulation was measured by the resultant surface temperature. A procedure was proposed to calibrate the effect of 3D heat flow, based on the analytical solution of the heat conduction equation, and thermal effusivity was measured. The derived values show good agreement with literature values. As a result, the TM calibration procedure can be recommended for practical use in measuring the thermal effusivity in a small region of the materials.

  1. Effect of Heating Rate on Glass Foaming: Transition to Bulk Foam

    Energy Technology Data Exchange (ETDEWEB)

    Hrma, Pavel R.

    2009-02-15

    Foaming of glass is an undesirable side effect of glass fining. According to a recent experimental study, the gas-phase volume in the melt heated at a constant rate dramatically increased with an increased rate of heating. This observation indicates that an increased rate of heating (a natural consequence of the increased processing rate experienced as a result of transition to oxy-fuel firing) may exert a substantial influence on glass foaming in advanced glass-melting furnaces. This paper attributes this effect to the change of mode of foam formation in response to an increased rate of heating.

  2. Heat storage rate and acute fatigue in rats

    Directory of Open Access Journals (Sweden)

    L.O.C. Rodrigues

    2003-01-01

    Full Text Available Thermal environmental stress can anticipate acute fatigue during exercise at a fixed intensity (%VO2max. Controversy exists about whether this anticipation is caused by the absolute internal temperature (Tint, ºC, by the heat storage rate (HSR, cal/min or by both mechanisms. The aim of the present study was to study acute fatigue (total exercise time, TET during thermal stress by determining Tint and HSR from abdominal temperature. Thermal environmental stress was controlled in an environmental chamber and determined as wet bulb globe temperature (ºC, with three environmental temperatures being studied: cold (18ºC, thermoneutral (23.1ºC or hot (29.4ºC. Six untrained male Wistar rats weighing 260-360 g were used. The animals were submitted to exercise at the same time of day in the three environments and at two treadmill velocities (21 and 24 m/min until exhaustion. After implantation of a temperature sensor and treadmill adaptation, the animals were submitted to a Latin square experimental design using a 2 x 3 factorial scheme (velocity and environment, with the level of significance set at P<0.05. The results showed that the higher the velocity and the ambient temperature, the lower was the TET, with these two factors being independent. This result indicated that fatigue was independently affected by both the increase in exercise intensity and the thermal environmental stress. Fatigue developed at different Tint and HSR showed the best inverse relationship with TET. We conclude that HSR was the main anticipating factor of fatigue.

  3. Prediction of Heat Transfer Rates for Shell-and-Tube Heat Exchangers by Artificial Neural Networks Approach

    Institute of Scientific and Technical Information of China (English)

    Qiuwang WANG; Gongnan XIE; Ming ZENG; Laiqin LUO

    2006-01-01

    This work used artificial neural network (ANN) to predict the heat transfer rates of shell-and-tube heat exchangers with segmental baffles or continuous helical baffles, based on limited experimental data. The Back Propagation (BP) algorithm was used in training the networks. Different network configurations were also studied. The deviation between the predicted results and experimental data was less than 2%. Comparison with correlation for prediction shows ANN superiority. It is recommended that ANN can be easily used to predict the performances of thermal systems in engineering applications, especially to model heat exchangers for heat transfer analysis.

  4. Heating rate effect on thermoluminescence glow curves of LiF:Mg,Cu,P+PTFE phosphor

    Energy Technology Data Exchange (ETDEWEB)

    Cruz-Zaragoza, E. [Instituto de Ciencias Nucleares, Universidad Nacional Autonoma de Mexico, A.P. 70-543, Mexico D.F. 04510 (Mexico); Gonzalez, P.R., E-mail: pedro.gonzalez@inin.gob.mx [Instituto Nacional de Investigaciones Nucleares, Carretera Mexico-Toluca S/N, C.P. 52750, Ocoyoacac, Estado de Mexico (Mexico); Azorin, J. [Universidad Autonoma Metropolitana-Iztapalapa, San Rafael Atlixco 186, 09340 Mexico D.F. (Mexico); Furetta, C. [Touro University Rome, Division of Touro College New York, Circne Gianicolense 15-17, 00153 Rome (Italy)

    2011-10-15

    The influence of heating rate on the thermoluminescence (TL) property of LiF:Mg,Cu,P+PTFE was analyzed. The activation energy and the frequency factor as a function of the heating rate were determined. The kinetic parameters and their dependence on the heating rate were evaluated using the sequential quadratic programming glow curve deconvolution (SQPGCD). The results showed that as the heating rate increases, the peak intensity at the maximum (I{sub M}) decreases and shifts to higher temperature; similar behavior of the kinetics parameters was observed. - Highlights: >Heating rate influence on the thermoluminescence (TL) property of LiF:Mg,Cu,P was analyzed. > The kinetic parameters, activation energy and frequency factor were evaluated using the sequential quadratic programming glow curve deconvolution. > The peak intensity at the maximum (I{sub M}) of the glow curves decreases. > Shifts to higher temperature were observed as the heating rate increased. > Similar behavior of the kinetics parameters was noticed.

  5. An examination of heat rate improvements due to waste heat integration in an oxycombustion pulverized coal power plant

    Science.gov (United States)

    Charles, Joshua M.

    Oxyfuel, or oxycombustion, technology has been proposed as one carbon capture technology for coal-fired power plants. An oxycombustion plant would fire coal in an oxidizer consisting primarily of CO2, oxygen, and water vapor. Flue gas with high CO2 concentrations is produced and can be compressed for sequestration. Since this compression generates large amounts of heat, it was theorized that this heat could be utilized elsewhere in the plant. Process models of the oxycombustion boiler, steam cycle, and compressors were created in ASPEN Plus and Excel to test this hypothesis. Using these models, heat from compression stages was integrated to the flue gas recirculation heater, feedwater heaters, and to a fluidized bed coal dryer. All possible combinations of these heat sinks were examined, with improvements in coal flow rate, Qcoal, net power, and unit heat rate being noted. These improvements would help offset the large efficiency impacts inherent to oxycombustion technology.

  6. A Simple Rate Law Experiment Using a Custom-Built Isothermal Heat Conduction Calorimeter

    Science.gov (United States)

    Wadso, Lars; Li, Xi.

    2008-01-01

    Most processes (whether physical, chemical, or biological) produce or consume heat: measuring thermal power (the heat production rate) is therefore a typical method of studying processes. Here we describe the design of a simple isothermal heat conduction calorimeter built for use in teaching; we also provide an example of its use in simultaneously…

  7. EFFECT OF HEATING RATE ON THE THERMODYNAMIC PROPERTIES OF PULVERIZED COAL

    Energy Technology Data Exchange (ETDEWEB)

    Ramanathan Sampath

    2000-01-01

    This final technical report describes work performed under DOE Grant No. DE-FG22-96PC96224 during the period September 24, 1996 to September 23, 1999 which covers the entire performance period of the project. During this period, modification, alignment, and calibration of the measurement system, measurement of devolatilization time-scales for single coal particles subjected to a range of heating rates and temperature data at these time-scales, and analysis of the temperature data to understand the effect of heating rates on coal thermal properties were carried out. A new thermodynamic model was developed to predict the heat transfer behavior for single coal particles using one approach based on the analogy for thermal property of polymers. Results of this model suggest that bituminous coal particles behave like polymers during rapid heating on the order of 10{sup 4}-10{sup 5} K/s. At these heating rates during the early stages of heating, the vibrational part of the heat capacity of the coal molecules appears to be still frozen but during the transition from heat-up to devolatilization, the heat capacity appears to attain a sudden jump in its value as in the case of polymers. There are a few data available in the coal literature for low heating rate experiments (10{sup 2}-10{sup 3} K/s) conducted by UTRC, our industrial partner, in this project. These data were obtained for a longer heating duration on the order of several seconds as opposed to the 10 milliseconds heating time of the single particle experiments discussed above. The polymer analogy model was modified to include longer heating time on the order of several seconds to test these data. However, the model failed to predict these low heating rate data. It should be noted that UTRC's work showed reasonably good agreement with Merrick model heat capacity predictions at these low heating rates, but at higher heating rates UTRC observed that coal thermal response was heat flux dependent. It is concluded

  8. Direct measurement of heat transfer rates and coefficients in freezing processes by the use of heat flux sensors

    Energy Technology Data Exchange (ETDEWEB)

    Amarante, A.; Lanoiselle, J.L.; Ramirez, A.

    2003-10-01

    Heat exchange is often complex to assess in freezing equipment. Either the extensive calculation procedures based on product time-temperature data, or the lack of accurate thermophysical properties, or even the non-uniform processing conditions in industrial equipment, results in increased difficulty in calculating accurate heat exchange parameters. The present study aims to solve this kind of problem by introducing the use of heat flux sensors (or fluxmeters) for an online measurement of heat exchange parameters during freezing processes. Since food products often have irregular, moist and greasy surfaces, bad attachment of the sensors can lead to low accuracy in heat flux measurement. First, a technique was improved in this particular and a numerical procedure based on matching the experimental and simulated temperature histories was used to calibrate the sensors attached to Tylose gels submitted to freezing and thawing cycles. Following this, the sensors were applied directly to a vegetable product undergoing freezing in a static freezer to measure the instantaneous product heat release rate and the local heat transfer coefficient. A fluxmeter-plastic transducer was also developed and used, coupled to an anemometer to map axially and transversally the local effective heat transfer coefficient and air speed profiles in a Super-Contact freezing tunnel. Results were compared with numerical simulations and showed good agreement. Irregular air speed distribution and low efficiency heat transfer zones were accurately detected, providing information for equipment optimization. (author)

  9. Dielectric properties and heating rate of broccoli powder as related to radio-frequency heating

    Science.gov (United States)

    Recently, Salmonella contamination was identified in low-moisture foods including dried vegetable powder. Radio Frequency (RF) dielectric heating is a potential alternative pasteurization method with short heating time. Dielectric properties of broccoli powder with 6.9, 9.1, 12.2, and 14.9%, w. b....

  10. THE POSSIBILITIES OF CO2 EMISSION REDUCTION IN THE PROCESS OF STEEL CHARGE HEATING THROUGH THE SELECTION OF HEATING RATE

    Directory of Open Access Journals (Sweden)

    Barbara Halusiak

    2015-08-01

    Full Text Available The reduction of carbon dioxide emission is an important aspect of the economic policy of each country. Institutions promoting environmental protection seek to reduce the level of greenhouse gas emissions. One of the main emitters of harmful gases to the atmosphere is the steelmaking sector. The heating technology used in metallurgical works contributes to the amount of emitted carbon dioxide that forms as a result of the loss of steel and the combustion of fuel, whose thermal energy is used during the course of the charge heating process in the heating furnace. Achieving the imposed ecological targets by not exceeding the specified emission level is possible by implementing appropriate pollutant emission reducing technologies in the metallurgical industry. Based on numerical computation results, the effect of heating rate on the emission of carbon dioxide has been determined in the paper. This study demonstrates that by selecting the appropriate steel charge heating technology the emissions of greenhouse gases can be substantially reduced.

  11. Convective Heat Transfer Scaling of Ignition Delay and Burning Rate with Heat Flux and Stretch Rate in the Equivalent Low Stretch Apparatus

    Science.gov (United States)

    Olson, Sandra

    2011-01-01

    To better evaluate the buoyant contributions to the convective cooling (or heating) inherent in normal-gravity material flammability test methods, we derive a convective heat transfer correlation that can be used to account for the forced convective stretch effects on the net radiant heat flux for both ignition delay time and burning rate. The Equivalent Low Stretch Apparatus (ELSA) uses an inverted cone heater to minimize buoyant effects while at the same time providing a forced stagnation flow on the sample, which ignites and burns as a ceiling fire. Ignition delay and burning rate data is correlated with incident heat flux and convective heat transfer and compared to results from other test methods and fuel geometries using similarity to determine the equivalent stretch rates and thus convective cooling (or heating) rates for those geometries. With this correlation methodology, buoyant effects inherent in normal gravity material flammability test methods can be estimated, to better apply the test results to low stretch environments relevant to spacecraft material selection.

  12. Analysis of Effect of Heat Pipe Parameters in Minimising the Entropy Generation Rate

    Directory of Open Access Journals (Sweden)

    Rakesh Hari

    2016-01-01

    Full Text Available Heat transfer and fluid flow in the heat pipe system result in thermodynamic irreversibility generating entropy. The minimum entropy generation principle can be used for optimum design of flat heat pipe. The objective of the present work is to minimise the total entropy generation rate as the objective function with different parameters of the flat heat pipe subjected to some constraints. These constraints constitute the limitations on the heat transport capacity of the heat pipe. This physical nonlinear programming problem with nonlinear constraints is solved using LINGO 15.0 software, which enables finding optimum values for the independent design variables for which entropy generation is minimum. The effect of heat load, length, and sink temperature on design variables and corresponding entropy generation is studied. The second law analysis using minimum entropy generation principle is found to be effective in designing performance enhanced heat pipe.

  13. Retrofits for improved heat rate and availability: Low-level heat recovery economizer retrofits

    Energy Technology Data Exchange (ETDEWEB)

    Rubow, L.N.; Borden, M.; Boulay, R.B.; Buchanan, T.L.; Granger, J.F.; Horazak, D.A.; Phillips, N.A. (Gilbert/Commonwealth, Inc., Reading, PA (United States))

    1992-06-01

    The subject of this report, involves the recovery of heat from the flue gas to preheat combustion air and protect the air heater. Flue gas is a large potential source of heat, but this mode of heat recovery has seen limited application due to the corrosive environment created in plant tail-end systems by condensation in sulfur-laden flue gases. Several installations of low-level economizers'' (LLEs) have experienced varied degrees of success using cast iron-type heat exchangers. Alternate materials that may be suitable for this application were investigated in this project. The cost of various types of installations with regard to equipment arrangement, remaining plant life, plant capacity factor, plant operating modes, ambient temperature characteristics, fuel costs, utility cost evaluation methods, and external economic factors were investigated.

  14. Mixing rates and vertical heat fluxes north of Svalbard from Arctic winter to spring

    Science.gov (United States)

    Meyer, Amelie; Fer, Ilker; Sundfjord, Arild; Peterson, Algot K.

    2017-06-01

    Mixing and heat flux rates collected in the Eurasian Basin north of Svalbard during the N-ICE2015 drift expedition are presented. The observations cover the deep Nansen Basin, the Svalbard continental slope, and the shallow Yermak Plateau from winter to summer. Mean quiescent winter heat flux values in the Nansen Basin are 2 W m-2 at the ice-ocean interface, 3 W m-2 in the pycnocline, and 1 W m-2 below the pycnocline. Large heat fluxes exceeding 300 W m-2 are observed in the late spring close to the surface over the Yermak Plateau. The data consisting of 588 microstructure profiles and 50 days of high-resolution under-ice turbulence measurements are used to quantify the impact of several forcing factors on turbulent dissipation and heat flux rates. Wind forcing increases turbulent dissipation seven times in the upper 50 m, and doubles heat fluxes at the ice-ocean interface. The presence of warm Atlantic Water close to the surface increases the temperature gradient in the water column, leading to enhanced heat flux rates within the pycnocline. Steep topography consistently enhances dissipation rates by a factor of four and episodically increases heat flux at depth. It is, however, the combination of storms and shallow Atlantic Water that leads to the highest heat flux rates observed: ice-ocean interface heat fluxes average 100 W m-2 during peak events and are associated with rapid basal sea ice melt, reaching 25 cm/d.

  15. Insensitivity of Ion Motional Heating Rate to Trap Material over a Large Temperature Range

    CERN Document Server

    Chiaverini, J

    2014-01-01

    We present measurements of trapped-ion motional-state heating rates in niobium and gold surface-electrode ion traps over a range of trap-electrode temperatures from approximately 4 K up to room temperature (295 K) in a single apparatus. Using the sideband-ratio technique after resolved-sideband cooling of single ions to the motional ground state, we find low-temperature heating rates more than two orders of magnitude below the room-temperature values and approximately equal to the lowest measured heating rates in similarly-sized cryogenic traps. We find similar behavior in the two very different electrode materials, suggesting that the anomalous heating process is dominated by non-material-specific surface contaminants. Through precise control of the temperature of cryopumping surfaces, we also identify conditions under which elastic collisions with the background gas can lead to an apparent steady heating rate, despite rare collisions.

  16. Prediction of the Scale Removal Rate in Heat Exchanger Piping

    Directory of Open Access Journals (Sweden)

    Najwa S. Majeed

    2010-01-01

    Full Text Available The possibility of predicting the mass transfer controlled CaCO3 scale removal rate has been investigated.Experiments were carried out using chelating agents as a cleaning solution at different time and Reynolds’s number. The results of CaCO3 scale removal or (mass transfer rate (as it is the controlling process are compared with proposed model of prandtl’s and Taylor particularly based on the concept of analogy among momentum and mass transfer.Correlation for the variation of Sherwood number ( or mass transfer rate with Reynolds’s number have been obtained .

  17. Prediction of the heat transfer rate of a single layer wire-on-tube type heat exchanger using ANFIS

    Energy Technology Data Exchange (ETDEWEB)

    Hayati, Mohsen [Electrical Engineering Department, Faculty of Engineering, Razi University, Tagh-E-Bostan, Kermanshah 67149 (Iran); Computational Intelligence Research Center, Razi University, Tagh-E-Bostan, Kermanshah 67149 (Iran); Rezaei, Abbas; Seifi, Majid [Electrical Engineering Department, Faculty of Engineering, Razi University, Tagh-E-Bostan, Kermanshah 67149 (Iran)

    2009-12-15

    In this paper, we applied an Adaptive Neuro-Fuzzy Inference System (ANFIS) model for prediction of the heat transfer rate of the wire-on-tube type heat exchanger. Limited experimental data was used for training and testing ANFIS configuration with the help of hybrid learning algorithm consisting of backpropagation and least-squares estimation. The predicted values are found to be in good agreement with the actual values from the experiments with mean relative error less than 2.55%. Also, we compared the proposed ANFIS model to an ANN approach. Results show that the ANFIS model has more accuracy in comparison to ANN approach. Therefore, we can use ANFIS model to predict the performances of thermal systems in engineering applications, such as modeling heat exchangers for heat transfer analysis. (author)

  18. Computer simulation of metal wire explosion under high rate heating

    Science.gov (United States)

    Zolnikov, K. P.; Kryzhevich, D. S.; Korchuganov, A. V.

    2017-05-01

    Synchronous electric explosion of metal wires and synthesis of bicomponent nanoparticles were investigated on the base of molecular dynamics method. Copper and nickel nanosized crystallites of cylindrical shape were chosen as conductors for explosion. The embedded atom approximation was used for calculation of the interatomic interactions. The agglomeration process after explosion metal wires was the main mechanism for particle synthesis. The distribution of chemical elements was non-uniform over the cross section of the bicomponent particles. The copper concentration in the surface region was higher than in the bulk of the synthesized particle. By varying the loading parameters (heating temperature, the distance between the wires) one can control the size and internal structure of the synthesized bicomponent nanoparticles. The obtained results showed that the method of molecular dynamics can be effectively used to determine the optimal technological mode of nanoparticle synthesis on the base of electric explosion of metal wires.

  19. The effect of heating rate on the surface chemistry of NiTi.

    Science.gov (United States)

    Undisz, Andreas; Hanke, Robert; Freiberg, Katharina E; Hoffmann, Volker; Rettenmayr, Markus

    2014-11-01

    The impact of the heating rate on the Ni content at the surface of the oxide layer of biomedical NiTi is explored. Heat treatment emulating common shape-setting procedures was performed by means of conventional and inductive heating for similar annealing time and temperature, applying various heating rates from ~0.25 K s(-1) to 250 K s(-1). A glow discharge optical emission spectroscopy method was established and employed to evaluate concentration profiles of Ni, Ti and O in the near-surface region at high resolution. The Ni content at the surface of the differently treated samples varies significantly, with maximum surface Ni concentrations of ~20 at.% at the lowest and ~1.5 at.% at the highest heating rate, i.e. the total amount of Ni contained in the surface region of the oxide layer decreases by >15 times. Consequently, the heating rate is a determinant for the biomedical characteristics of NiTi, especially since Ni available at the surface of the oxide layer may affect the hemocompatibility and be released promptly after surgical application of a respective implant. Furthermore, apparently contradictory results presented in the literature reporting surface Ni concentrations of ~3 at.% to >20 at.% after heat treatment are consistently explained considering the ascertained effect of the heating rate.

  20. Energy savings and higher volumetric loading rate achieved in the conventional anoxic-oxic process for sewage treatment by enhancing biomass retention in the secondary clarifier.

    Science.gov (United States)

    Zhang, Xueyu; Liu, Fengyuan; Zheng, Shaokui

    2017-06-01

    This is the first study to achieve a short HRT (∼2h for the A/O reactor), high MLSS (∼10gL(-1)), and high volumetric loading (∼3.7kg CODm(-3)d(-1) and ∼0.6kg NH4-Nm(-3)d(-1)) in the A/O process for sewage treatment by enhancing biomass retention in the secondary clarifier (∼4h settling time), which we refer to as the high-performance A/O process (HP-A/O) in this paper. Over 258days of continuous operation, with a decrease in HRT from 12 to 2h, remarkable COD (95±3%), NH4(+)-N (98±2%), TN (79±5%), and TP (74±10%) removals were stably achieved, while the air requirement significantly decreased by 22%. The HP-A/O process offers advantages over the conventional A/O process (6-8h for A/O reactor, 3-5gL(-1)MLSS, and ∼1.0kg CODm(-3)d(-1)) for sewage treatment in terms of its lower energy consumption, smaller footprint and reactor requirements. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. White Matter Lesion Assessment in Patients with Cognitive Impairment and Healthy Controls: Reliability Comparisons between Visual Rating, a Manual, and an Automatic Volumetrical MRI Method—The Gothenburg MCI Study

    Directory of Open Access Journals (Sweden)

    Erik Olsson

    2013-01-01

    Full Text Available Age-related white matter lesions (WML are a risk factor for stroke, cognitive decline, and dementia. Different requirements are imposed on methods for the assessment of WML in clinical settings and for research purposes, but reliability analysis is of major importance. In this study, WML assessment with three different methods was evaluated. In the Gothenburg mild cognitive impairment study, MRI scans from 152 participants were used to assess WML with the Fazekas visual rating scale on T2 images, a manual volumetric method on FLAIR images, and FreeSurfer volumetry on T1 images. Reliability was acceptable for all three methods. For low WML volumes (2/3 of the patients, reliability was overall lower and nonsignificant for the manual volumetric method. Unreliability in the assessment of patients with low WML with manual volumetry may mainly be due to intensity variation in the FLAIR sequence used; hence, intensity standardization and normalization methods must be used for more accurate assessments. The FreeSurfer segmentations resulted in smaller WML volumes than the volumes acquired with the manual method and showed deviations from visible hypointensities in the T1 images, which quite likely reduces validity.

  2. Heat Conduction in a Functionally Graded Plate Subjected to Finite Cooling/Heating Rates: An Asymptotic Solution

    Directory of Open Access Journals (Sweden)

    Zhihe Jin

    2011-12-01

    Full Text Available This work investigates transient heat conduction in a functionally graded plate (FGM plate subjected to gradual cooling/heating at its boundaries. The thermal properties of the FGM are assumed to be continuous and piecewise differentiable functions of the coordinate in the plate thickness direction. A linear ramp function describes the cooling/heating rates at the plate boundaries. A multi-layered material model and Laplace transform are employed to obtain the transformed temperatures at the interfaces between the layers. An asymptotic analysis and an integration technique are then used to obtain a closed form asymptotic solution of the temperature field in the FGM plate for short times. The thermal stress intensity factor (TSIF for an edge crack in the FGM plate calculated based on the asymptotic temperature solution shows that the asymptotic solution can capture the peak TSIFs under the finite cooling rate conditions.

  3. Effect of the Heat Flux Density on the Evaporation Rate of a Distilled Water Drop

    Directory of Open Access Journals (Sweden)

    Ponomarev Konstantin

    2016-01-01

    Full Text Available This paper presents the experimental dependence of the evaporation rate of a nondeaerated distilled water drop from the heat flux density on the surfaces of non-ferrous metals (copper and brass. A drop was placed on a heated substrate by electronic dosing device. To obtain drop profile we use a shadow optical system; drop symmetry was controlled by a high-speed video camera. It was found that the evaporation rate of a drop on a copper substrate is greater than on a brass. The evaporation rate increases intensively with raising volume of a drop. Calculated values of the heat flux density and the corresponding evaporation rates are presented in this work. The evaporation rate is found to increase intensively on the brass substrate with raising the heat flux density.

  4. Effects of mass flow rate and droplet velocity on surface heat flux during cryogen spray cooling

    Energy Technology Data Exchange (ETDEWEB)

    Karapetian, Emil [Department of Chemical Engineering and Material Sciences, University of California, Irvine, CA (United States); Aguilar, Guillermo [Department of Biomedical Engineering, University of California, Irvine, CA (United States); Kimel, Sol [Beckman Laser Institute, University of California, Irvine, CA (United States); Lavernia, Enrique J [Department of Chemical Engineering and Material Sciences, University of California, Irvine, CA (United States); Nelson, J Stuart [Department of Biomedical Engineering, University of California, Irvine, CA (United States)

    2003-01-07

    Cryogen spray cooling (CSC) is used to protect the epidermis during dermatologic laser surgery. To date, the relative influence of the fundamental spray parameters on surface cooling remains incompletely understood. This study explores the effects of mass flow rate and average droplet velocity on the surface heat flux during CSC. It is shown that the effect of mass flow rate on the surface heat flux is much more important compared to that of droplet velocity. However, for fully atomized sprays with small flow rates, droplet velocity can make a substantial difference in the surface heat flux. (note)

  5. Can reptile embryos influence their own rates of heating and cooling?

    Science.gov (United States)

    Du, Wei-Guo; Tu, Ming-Chung; Radder, Rajkumar S; Shine, Richard

    2013-01-01

    Previous investigations have assumed that embryos lack the capacity of physiological thermoregulation until they are large enough for their own metabolic heat production to influence nest temperatures. Contrary to intuition, reptile embryos may be capable of physiological thermoregulation. In our experiments, egg-sized objects (dead or infertile eggs, water-filled balloons, glass jars) cooled down more rapidly than they heated up, whereas live snake eggs heated more rapidly than they cooled. In a nest with diel thermal fluctuations, that hysteresis could increase the embryo's effective incubation temperature. The mechanisms for controlling rates of thermal exchange are unclear, but may involve facultative adjustment of blood flow. Heart rates of snake embryos were higher during cooling than during heating, the opposite pattern to that seen in adult reptiles. Our data challenge the view of reptile eggs as thermally passive, and suggest that embryos of reptile species with large eggs can influence their own rates of heating and cooling.

  6. Can reptile embryos influence their own rates of heating and cooling?

    Directory of Open Access Journals (Sweden)

    Wei-Guo Du

    Full Text Available Previous investigations have assumed that embryos lack the capacity of physiological thermoregulation until they are large enough for their own metabolic heat production to influence nest temperatures. Contrary to intuition, reptile embryos may be capable of physiological thermoregulation. In our experiments, egg-sized objects (dead or infertile eggs, water-filled balloons, glass jars cooled down more rapidly than they heated up, whereas live snake eggs heated more rapidly than they cooled. In a nest with diel thermal fluctuations, that hysteresis could increase the embryo's effective incubation temperature. The mechanisms for controlling rates of thermal exchange are unclear, but may involve facultative adjustment of blood flow. Heart rates of snake embryos were higher during cooling than during heating, the opposite pattern to that seen in adult reptiles. Our data challenge the view of reptile eggs as thermally passive, and suggest that embryos of reptile species with large eggs can influence their own rates of heating and cooling.

  7. Tailoring the characteristics of carbonized wood charcoal by using different heating rates

    Science.gov (United States)

    Kwon, Gu-Joong; Kim, Dae-Young; Oh, Choong-Hyeon; Park, Byung-Ho; Kang, Joo-Hyon

    2014-05-01

    This study examined the characteristics of charcoals generated from White Lauan ( Pentacmecontorta) and Punah ( Tetrameristaglabra) by using different carbonization temperatures and heating rates. The scanning electron micrographs showed vestured pits in the White Lauan and raphide crystals in Punah as their respective anatomical characteristics. A slower heating rate resulted in a lower temperature to obtain the same amount of weight loss, regardless of the species being tested. A greater charcoal yield was obtained at a higher heating rate. The specific surface area was smaller in the charcoal produced at a higher carbonization temperature, but the heating rate had little effected. For both wood species, the axial compressive strength of the charcoal increased as the carbonization temperature was increased. The X-ray diffractograms of White Lauan and Punah woods heated at 1200°C indicated thermal decomposition of the crystal structure of cellulose, but no appreciable structural changes occurred under the tested heating rate conditions. Overall, the heating rate affected the charcoal yield but not the specific surface area, compressive strength, and crystal structure.

  8. R&D on Resistive Heat Exchangers for HTS High Rated Current Leads%R&D on Resistive Heat Exchangers for HTS High Rated Current Leads

    Institute of Scientific and Technical Information of China (English)

    毕延芳

    2011-01-01

    The HTS current leads of superconducting magnets for large scale fusion devices and high energy particle colliders can reduce the power consumption for cooling by 2/3 compared with conventional leads. The resistive sections of high-rated current leads are usually made of a heat exchanger cooled by gas flow. The supply of the cooling mass flow incurs more than 90% of the cooling cost for the HTS leads. The mass flow rate requirement depends not only on the length and material of the resistive heat exchanger, but also on the heat transfer coefficient and HEX surface, the joint resistance at the cold end of a sheet-stack HEX with a larger specific presented in the paper. The test results of efficiency can be achieved. and its cooling approach. The design and operation surface and a much smaller hydraulic diameter are an HTS lead optimized for 8 kA show that a 98.4%

  9. Volumetric composition of nanocomposites

    DEFF Research Database (Denmark)

    Madsen, Bo; Lilholt, Hans; Mannila, Juha

    2015-01-01

    Detailed characterisation of the properties of composite materials with nanoscale fibres is central for the further progress in optimization of their manufacturing and properties. In the present study, a methodology for the determination and analysis of the volumetric composition of nanocomposites...... is presented, using cellulose/epoxy and aluminosilicate/polylactate nanocomposites as case materials. The buoyancy method is used for the accurate measurements of materials density. The accuracy of the method is determined to be high, allowing the measured nanocomposite densities to be reported with 5...... significant figures. The plotting of the measured nanocomposite density as a function of the nanofibre weight content is shown to be a first good approach of assessing the porosity content of the materials. The known gravimetric composition of the nanocomposites is converted into a volumetric composition...

  10. Thermogravimetric characteristics of char obtained at high heat rate

    Directory of Open Access Journals (Sweden)

    Andrés Felipe Rojas González

    2010-05-01

    700°C, 800°C and 900°C to obtain their combustion profiles. Characteristic temperatures (ignition, peak and final tempe- ratures were determined by non-isothermal thermogravimetry; it was found that chars from La Yolanda coal gave the highest figures for the characteristic temperatures. Isothermal thermogravimetry revealed that the combustion rate for the three coals decreased with increased devolatilisation time and combustion temperature.

  11. Nonequilibrium volumetric response of shocked polymers

    Energy Technology Data Exchange (ETDEWEB)

    Clements, B E [Los Alamos National Laboratory

    2009-01-01

    Polymers are well known for their non-equilibrium deviatoric behavior. However, investigations involving both high rate shock experiments and equilibrium measured thermodynamic quantities remind us that the volumetric behavior also exhibits a non-equilibrium response. Experiments supporting the notion of a non-equilibrium volumetric behavior will be summarized. Following that discussion, a continuum-level theory is proposed that will account for both the equilibrium and non-equilibrium response. Upon finding agreement with experiment, the theory is used to study the relaxation of a shocked polymer back towards its shocked equilibrium state.

  12. Heat-Rate Improvement Obtained by Retubing Power-Plant Condenser Enhanced Tubes

    Energy Technology Data Exchange (ETDEWEB)

    1994-01-21

    A utility will only retube a condenser with enhanced tubes if the incremental cost of the enhanced tubes can be offset with reduced fuel costs. The reduced fuel cost is obtained for some units because of the higher heat-transfer coefficient of enhanced tubes. They lead to improved condenser performance measured by a lower condenser pressure and therefore a more efficient power plant. However, the higher haet-transfer coefficients do not always guarantee that enhanced tubes will be more cost effective. Other issues must be considered such as the cooling-water flow reduction due to the increased pressure drop, the low-pressure turbine heat-rate variation with backpressure, and the cooling-water pump and system characteristics. These and other parameters must be considered to calculate the efficiency improvement of the power plant as commonly measured by the quantity known as the heat rate. Knowing the heat-rate improvement, the fuel cost, and the incremental increase of the enhanced tubes from the supplier, the payback time can be determined. This program calculates the heat-rate improvement that can be obtained by retubing a power plant condenser with enhanced tubes of a particular type called Korodense LPD made by Wolverine Tube, Inc. The fuel savings are easily established knowing the heat-rate improvement. All electrical utilities are potential users because a condenser is used as the heat sink for every power plant.

  13. HTRATE; Heat-Rate Improvement Obtained by Retubing Power-Plant Condenser Enhanced Tubes

    Energy Technology Data Exchange (ETDEWEB)

    Rabas, T.J. [Argonne National Lab., IL (United States)

    1990-06-01

    A utility will only retube a condenser with enhanced tubes if the incremental cost of the enhanced tubes can be offset with reduced fuel costs. The reduced fuel cost is obtained for some units because of the higher heat-transfer coefficient of enhanced tubes. They lead to improved condenser performance measured by a lower condenser pressure and therefore a more efficient power plant. However, the higher haet-transfer coefficients do not always guarantee that enhanced tubes will be more cost effective. Other issues must be considered such as the cooling-water flow reduction due to the increased pressure drop, the low-pressure turbine heat-rate variation with backpressure, and the cooling-water pump and system characteristics. These and other parameters must be considered to calculate the efficiency improvement of the power plant as commonly measured by the quantity known as the heat rate. Knowing the heat-rate improvement, the fuel cost, and the incremental increase of the enhanced tubes from the supplier, the payback time can be determined. This program calculates the heat-rate improvement that can be obtained by retubing a power plant condenser with enhanced tubes of a particular type called Korodense LPD made by Wolverine Tube, Inc. The fuel savings are easily established knowing the heat-rate improvement. All electrical utilities are potential users because a condenser is used as the heat sink for every power plant.

  14. Average Rate of Heat-Related Hospitalizations in 23 States, 2001-2010

    Data.gov (United States)

    U.S. Environmental Protection Agency — This map shows the 2001–2010 average rate of hospitalizations classified as “heat-related” by medical professionals in 23 states that participate in CDC’s...

  15. Heat transfer in a microvascular network: the effect of heart rate on heating and cooling in reptiles (Pogona barbata and Varanus varius).

    Science.gov (United States)

    Seebacher, F

    2000-03-21

    Thermally-induced changes in heart rate and blood flow in reptiles are believed to be of selective advantage by allowing animal to exert some control over rates of heating and cooling. This notion has become one of the principal paradigms in reptilian thermal physiology. However, the functional significance of changes in heart rate is unclear, because the effect of heart rate and blood flow on total animal heat transfer is not known. I used heat transfer theory to determine the importance of heat transfer by blood flow relative to conduction. I validated theoretical predictions by comparing them with field data from two species of lizard, bearded dragons (Pogona barbata) and lace monitors (Varanus varius). Heart rates measured in free-ranging lizards in the field were significantly higher during heating than during cooling, and heart rates decreased with body mass. Convective heat transfer by blood flow increased with heart rate. Rates of heat transfer by both blood flow and conduction decreased with mass, but the mass scaling exponents were different. Hence, rate of conductive heat transfer decreased more rapidly with increasing mass than did heat transfer by blood flow, so that the relative importance of blood flow in total animal heat transfer increased with mass. The functional significance of changes in heart rate and, hence, rates of heat transfer, in response to heating and cooling in lizards was quantified. For example, by increasing heart rate when entering a heating environment in the morning, and decreasing heart rate when the environment cools in the evening a Pogona can spend up to 44 min longer per day with body temperature within its preferred range. It was concluded that changes in heart rate in response to heating and cooling confer a selective advantage at least on reptiles of mass similar to that of the study animals (0. 21-5.6 kg). Copyright 2000 Academic Press.

  16. An analysis of representative heating load lines for residential HSPF ratings

    Energy Technology Data Exchange (ETDEWEB)

    Rice, C. Keith [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Shen, Bo [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Shrestha, Som S. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2015-07-01

    This report describes an analysis to investigate representative heating loads for single-family detached homes using current EnergyPlus simulations (DOE 2014a). Hourly delivered load results are used to determine binned load lines using US Department of Energy (DOE) residential prototype building models (DOE 2014b) developed by Pacific Northwest National Laboratory (PNNL). The selected residential single-family prototype buildings are based on the 2006 International Energy Conservation Code (IECC 2006) in the DOE climate regions. The resulting load lines are compared with the American National Standards Institute (ANSI)/Air-Conditioning, Heating, and Refrigeration Institute (AHRI) Standard 210/240 (AHRI 2008) minimum and maximum design heating requirement (DHR) load lines of the heating seasonal performance factor (HSPF) ratings procedure for each region. The results indicate that a heating load line closer to the maximum DHR load line, and with a lower zero load ambient temperature, is more representative of heating loads predicted for EnergyPlus prototype residential buildings than the minimum DHR load line presently used to determine HSPF ratings. An alternative heating load line equation was developed and compared to binned load lines obtained from the EnergyPlus simulation results. The effect on HSPF of the alternative heating load line was evaluated for single-speed and two-capacity heat pumps, and an average HSPF reduction of 16% was found. The alternative heating load line relationship is tied to the rated cooling capacity of the heat pump based on EnergyPlus autosizing, which is more representative of the house load characteristics than the rated heating capacity. The alternative heating load line equation was found to be independent of climate for the six DOE climate regions investigated, provided an adjustable zero load ambient temperature is used. For Region IV, the default DOE climate region used for HSPF ratings, the higher load line results in an ~28

  17. Modeling and Experimental Validation of a Volumetric Expander Suitable for Waste Heat Recovery from an Automotive Internal Combustion Engine Using an Organic Rankine Cycle with Ethanol

    Directory of Open Access Journals (Sweden)

    José Galindo

    2016-04-01

    Full Text Available Waste heat recovery (WHR in exhaust gas flow of automotive engines has proved to be a useful path to increase the overall efficiency of internal combustion engines (ICE. Recovery potentials of up to 7% are shown in several works in the literature. However, most of them are theoretical estimations. Some present results from prototypes fed by steady flows generated in an auxiliary gas tank and not with actual engine exhaust gases. This paper deals with the modeling and experimental validation of an organic Rankine cycle (ORC with a swash-plate expander integrated in a 2 L turbocharged petrol engine using ethanol as working fluid. A global simulation model of the ORC was developed with a maximum difference of 5%, validated with experimental results. Considering the swash-plate as the main limiting factor, an additional specific submodel was implemented to model the physical phenomena in this element. This model allows simulating the fluid dynamic behavior of the swash-plate expander using a 0D model (Amesim. Differences up to 10.5% between tests and model results were found.

  18. Investigating the performance of simplified neutral-ion collisional heating rate in a global IT model

    Science.gov (United States)

    Zhu, Jie; Ridley, Aaron J.

    2016-01-01

    The Joule heating rate has usually been used as an approximate form of the neutral-ion collisional heating rate in the thermospheric energy equation in global thermosphere-ionosphere models. This means that the energy coupling has ignored the energy gained by the ions from collisions with electrons. It was found that the globally averaged thermospheric temperature (Tn) was underestimated in simulations using the Joule heating rate, by about 11% when F10.7=110 solar flux unit (sfu, 1 sfu = 10-22 W m-2 Hz-1) in a quiet geomagnetic condition. The underestimation of Tn was higher at low latitudes than high latitudes, and higher at F region altitudes than at E region altitudes. It was found that adding additional neutral photoelectron heating in a global IT model compensated for the underestimation of Tn using the Joule heating approximation. Adding direct photoelectron heating to the neutrals compensated for the indirect path for the energy that flows from the electrons to the ions then to the neutrals naturally and therefore was an adequate compensation over the dayside. There was a slight dependence of the underestimation of Tn on F10.7, such that larger activity levels resulted in a need for more compensation in direct photoelectron heating to the neutrals to make up for the neglected indirect heating through ions and electrons.

  19. Effect of Heating Rates on the Formable Oxide Scale on a C-Steel Surface

    Institute of Scientific and Technical Information of China (English)

    A.A.El-Meligi

    2004-01-01

    Oxide scale formation on a C-steel surface has been investigated using linear heating rates ranging from 0.1℃/min to 10℃/min at high temperatures. The studies on the oxide scale formation at high temperature (650℃) at slower heating rate (0.1℃/min) shows that the kinetic regime is linear. X-ray diffraction measurements revealed that the scale constituents are significantly influenced by the heating rate. The adherence of the scale was improved by using slower heating rate (0.1℃/min-≤650℃),while above such degree the scale was susceptible to cracking and flaking out of the alloy surface. In fact, the development of oxide growth stresses can cause considerable scale cracking. As well, variation of the crystallite sizes under the aforementioned conditions might affect the scale stacking to the alloy surface. The secondary electron detector images of the oxide scale shows that the scale was imperfectly smooth and there were a number of voids and defects in the scale skin, especially at fast heating rate. This observation could be attributed to defects of the as-received alloy. In general, slower heating rate reduced the defects of the scale and improved its adherence.

  20. Heat accumulation during high repetition rate ultrafast laser interaction: Waveguide writing in borosilicate glass

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Haibin; Eaton, Shane M; Li, Jianzhao; Herman, Peter R [The Edward S. Rogers Sr. Department of Electrical and Computer Engineering, University of Toronto, 10 King' s College Road, Toronto, ON, M5S 3G4 (Canada)

    2007-04-15

    During high repetition rate (>200 kHz) ultrafast laser waveguide writing, visible heat modified zones surrounding the formed waveguide occur as a result of heat accumulation. The radii of the heat-modified zones increase with the laser net fluence, and were found to correlate with the formation of low-loss and cylindrically symmetric optical waveguides. A numerical thermal model based on the finite difference method is applied here to account for cumulative heating and diffusion effects. The model successfully shows that heat propagation and accumulation accurately predict the radius of the 'heat modified' zones observed in borosilicate glass waveguides formed across a wide range of laser exposure conditions. Such modelling promises better control of thermal effects for optimizing the fabrication and performance of three-dimensional optical devices in transparent materials.

  1. Dilatometric and hardness analysis of C45 steel tempering with different heating-up rates

    Directory of Open Access Journals (Sweden)

    A. Kulawik

    2012-01-01

    Full Text Available Modelling of technological processes of heat treatment or welding, involving multiple heat source transitions, requires considering the phenomenon of tempering. In work have been presented results of dilatometric research of hardened C45 steel subjected to tempering. The analysis of the influence of heating rate at the kinetic determined from dilatometric curves has been made. There have also been estimated quantities of transformation expansions and thermal expansion coefficients of hardening and tempering structures (austenite, ferrite, pearlite, martensite and sorbite. The analysis of tempering time influence on the hardness of tempered steel has been made. Functions associating hardness with tempering time (rate of heating-up in technological processes based on short-timed action of a heat source (eg. laser treatment have been suggested.

  2. Experimental test of the heating and cooling rate effect on blocking temperatures

    Science.gov (United States)

    Berndt, Thomas; Paterson, Greig A.; Cao, Changqian; Muxworthy, Adrian R.

    2017-07-01

    The cooling rates at which rocks acquire thermoremanent magnetizations (TRMs), affect their unblocking temperatures in thermal demagnetization experiments; similarly the heating rates at which the thermal demagnetization experiments are done also affect the unblocking temperature. We have tested the effects of variable cooling and heating rates on the unblocking temperatures of two natural non-interacting, magnetically uniform (single-domain, SD) (titano)magnetite samples and a synthetic SD magnetoferritin sample. While previous studies have only considered unblocking temperatures for stepwise thermal demagnetization data (i.e. the room-temperature magnetization after incremental heating), in this work we derive an expression for continuous thermal demagnetization of both TRMs and viscous remanent magnetizations (VRMs) and relate the heating rate to an effective equivalent hold time of a stepwise thermal demagnetization experiment. Through our analysis we reach four main conclusions: First, the theoretical expressions for the heating/cooling rate effect do not accurately predict experimentally observed blocking temperatures. Empirically, the relation can be modified incorporating a factor that amplifies both the temperature and the heating rate dependence of the heating/cooling rate effect. Using these correction factors, Pullaiah nomograms can accurately predict blocking temperatures of both TRMs and VRMs for continuous heating/cooling. Second, demagnetization temperatures are approximately predicted by published 'Pullaiah nomograms', but blocking occurs gradually over temperature intervals of 5-40 K. Third, the theoretically predicted temperatures correspond to ∼54-82 per cent blocking, depending on the sample. Fourth, the blocking temperatures can be used to obtain estimates of the atomic attempt time τ0, which were found to be 3 × 10-10 s for large grained (titano)magnetite, 1 × 10-13 s for small grained (titano)magnetite below the Verwey transition and 9

  3. Effect of heating rate on structure of VT23 and VT6 quenched alloys

    Energy Technology Data Exchange (ETDEWEB)

    Ivasishin, O.M.; Oshkaderov, S.P. (AN Ukrainskoj SSR, Kiev. Inst. Metallofiziki)

    1982-01-01

    The grain and intergrain structures of two-phase VT23 and VT6 titanium alloys with an initial fine-grain structure quenched after heating with different rates in (..cap alpha..+..beta..) and ..beta..-regions were studied. The heating rate increase from 0.2 up to 200 deg/s is shown to result in the monotonic growth of a polymorphic transformation temperature, the decrease of grain size at a constant quenching temperature, the appearance of a grain size change jump, and the martensite grain refinement during heating up to ..beta..-region temperatures. The high-rate heating of VT23 and VT6 quenched alloys permits to build up dispersion intergranular structure and to control their properties.

  4. Measurement of Ion Motional Heating Rates over a Range of Trap Frequencies and Temperatures

    CERN Document Server

    Bruzewicz, C D; Chiaverini, J

    2014-01-01

    We present measurements of the motional heating rate of a trapped ion at different trap frequencies and temperatures between $\\sim$0.6 and 1.5 MHz and $\\sim$4 and 295 K. Additionally, we examine the possible effect of adsorbed surface contaminants with boiling points below $\\sim$105$^{\\circ}$C by measuring the ion heating rate before and after locally baking our ion trap chip under ultrahigh vacuum conditions. We compare the heating rates presented here to those calculated from available electric-field noise models. We can tightly constrain a subset of these models based on their expected frequency and temperature scaling interdependence. Discrepancies between the measured results and predicted values point to the need for refinement of theoretical noise models in order to more fully understand the mechanisms behind motional trapped-ion heating.

  5. Method and device for determining heats of combustion of gaseous hydrocarbons

    Science.gov (United States)

    Singh, Jag J. (Inventor); Sprinkle, Danny R. (Inventor); Puster, Richard L. (Inventor)

    1988-01-01

    A method and device is provided for a quick, accurate and on-line determination of heats of combustion of gaseous hydrocarbons. First, the amount of oxygen in the carrier air stream is sensed by an oxygen sensing system. Second, three individual volumetric flow rates of oxygen, carrier stream air, and hydrocrabon test gas are introduced into a burner. The hydrocarbon test gas is fed into the burner at a volumetric flow rate, n, measured by a flowmeter. Third, the amount of oxygen in the resulting combustion products is sensed by an oxygen sensing system. Fourth, the volumetric flow rate of oxygen is adjusted until the amount of oxygen in the combustion product equals the amount of oxygen previously sensed in the carrier air stream. This equalizing volumetric flow rate is m and is measured by a flowmeter. The heat of combustion of the hydrocrabon test gas is then determined from the ratio m/n.

  6. Effect of Heating Rate on the Pressureless Sintering Densification of a Nickel-Based Superalloy

    Science.gov (United States)

    Levasseur, David; Brochu, Mathieu

    2016-05-01

    Pressureless sintering of Inconel 718 has important technological applications for the densification of metal injection molding or additive manufacturing of parts with powder/binder systems. The effect of heating rates ranging from 15 to 200 K/minute on the sintering behavior of fine (-325 mesh) Inconel 718 powders was studied using the master sintering curve (MSC) concept. A pressureless pulsed electric current sintering setup was used to heat samples. The temperature at the onset of sintering increased as the heating rate increased. The formation of a supersolidus liquid fraction was shifted toward higher temperatures for increased heating rates. The apparent activation energy of sintering was obtained by least squares fitting of the sintering data to the MSC and was in good agreement with the lattice diffusion activation energy of the alloying elements present in Inconel 718. The MSC followed different kinetics for low heating rates (≤50 K/minute) and high heating rates (≥75 K/minute), and these differences were related to liquation kinetics.

  7. The heating rate in the tropical tropopause region; Die Erwaermungsrate in der tropischen Tropopausenregion

    Energy Technology Data Exchange (ETDEWEB)

    Hamann, Ulrich

    2010-07-01

    The major part of the movement of air masses from the troposphere to the stratosphere takes place in the tropics. The conveyed air mass is transported with the Brewer-Dobson circulation poleward and therefore influences the global stratospheric composition. An important cause variable for the transport of air through the tropical tropopause layer (TTL) is the radiative heating, which is investigated in this work. The influence of trace gases, temperature, and cloudiness on the heating rate is quantified, especially the effect of the overlap of several cloud layers is discussed. The heating rate in the tropics is simulated for one year. Regional differences of the heating rate profile appear between convective and stably stratified regions. By means of trace gas concentrations, temperature, and heating rates it is determined that an enhanced transport of air through the TTL took place between January and April 2007. The comparison with previous works shows that accurate input data sets of trace gases, temperature, and cloudiness and exact methods for the simulation of the radiative transfer are indispensable for modeling of the heating rate with the required accuracy. (orig.)

  8. Influence of heat transfer rates on pressurization of liquid/slush hydrogen propellant tanks

    Science.gov (United States)

    Sasmal, G. P.; Hochstein, J. I.; Hardy, T. L.

    1993-01-01

    A multi-dimensional computational model of the pressurization process in liquid/slush hydrogen tank is developed and used to study the influence of heat flux rates at the ullage boundaries on the process. The new model computes these rates and performs an energy balance for the tank wall whereas previous multi-dimensional models required a priori specification of the boundary heat flux rates. Analyses of both liquid hydrogen and slush hydrogen pressurization were performed to expose differences between the two processes. Graphical displays are presented to establish the dependence of pressurization time, pressurant mass required, and other parameters of interest on ullage boundary heat flux rates and pressurant mass flow rate. Detailed velocity fields and temperature distributions are presented for selected cases to further illuminate the details of the pressurization process. It is demonstrated that ullage boundary heat flux rates do significantly effect the pressurization process and that minimizing heat loss from the ullage and maximizing pressurant flow rate minimizes the mass of pressurant gas required to pressurize the tank. It is further demonstrated that proper dimensionless scaling of pressure and time permit all the pressure histories examined during this study to be displayed as a single curve.

  9. Flexible Volumetric Structure

    Science.gov (United States)

    Cagle, Christopher M. (Inventor); Schlecht, Robin W. (Inventor)

    2014-01-01

    A flexible volumetric structure has a first spring that defines a three-dimensional volume and includes a serpentine structure elongatable and compressible along a length thereof. A second spring is coupled to at least one outboard edge region of the first spring. The second spring is a sheet-like structure capable of elongation along an in-plane dimension thereof. The second spring is oriented such that its in-plane dimension is aligned with the length of the first spring's serpentine structure.

  10. The Effect of Heat Treatments and Coatings on the Outgassing Rate of Stainless Steel Chambers

    Energy Technology Data Exchange (ETDEWEB)

    Mamum, Md Abdullah A. [Old Dominion Univ., Norfolk, VA (United States); Elmustafa, Abdelmageed A, [Old Dominion Univ., Norfolk, VA (United States); Stutzman, Marcy L. [JLAB, Newport News, VA (United States); Adderley, Philip A. [JLAB, Newport News, VA (United States); Poelker, Matthew [JLAB, Newport News, VA (United States)

    2014-03-01

    The outgassing rates of four nominally identical 304L stainless steel vacuum chambers were measured to determine the effect of chamber coatings and heat treatments. One chamber was coated with titanium nitride (TiN) and one with amorphous silicon (a-Si) immediately following fabrication. One chamber remained uncoated throughout, and the last chamber was first tested without any coating, and then coated with a-Si following a series of heat treatments. The outgassing rate of each chamber was measured at room temperatures between 15 and 30 deg C following bakes at temperatures between 90 and 400 deg C. Measurements for bare steel showed a significant reduction in the outgassing rate by more than a factor of 20 after a 400 deg C heat treatment (3.5 x 10{sup 12} TorrL s{sup -1}cm{sup -2} prior to heat treatment, reduced to 1.7 x 10{ sup -13} TorrL s{sup -1}cm{sup -2} following heat treatment). The chambers that were coated with a-Si showed minimal change in outgassing rates with heat treatment, though an outgassing rate reduced by heat treatments prior to a-Si coating was successfully preserved throughout a series of bakes. The TiN coated chamber exhibited remarkably low outgassing rates, up to four orders of magnitude lower than the uncoated stainless steel. An evaluation of coating composition suggests the presence of elemental titanium which could provide pumping and lead to an artificially low outgassing rate. The outgassing results are discussed in terms of diffusion-limited versus recombination-limited processes.

  11. Modeling the influence of potassium content and heating rate on biomass pyrolysis

    DEFF Research Database (Denmark)

    Trubetskaya, Anna; Surup, Gerrit; Shapiro, Alexander

    2017-01-01

    This study presents a combined kinetic and particle model that describes the effect of potassium and heating rate during the fast pyrolysis of woody and herbaceous biomass. The model calculates the mass loss rate, over a wide range of operating conditions relevant to suspension firing. The shrink......This study presents a combined kinetic and particle model that describes the effect of potassium and heating rate during the fast pyrolysis of woody and herbaceous biomass. The model calculates the mass loss rate, over a wide range of operating conditions relevant to suspension firing....... The shrinking particle model considers internal and external heat transfer limitations and incorporates catalytic effects of potassium on the product yields. Modeling parameters were tuned with experimentally determined char yields at high heating rates (>200 K s−1) using a wire mesh reactor, a single particle...... burner, and a drop tube reactor. The experimental data demonstrated that heating rate and potassium content have significant effects on the char yield. The importance of shrinkage on the devolatilization time becomes greater with increasing particle size, but showed little influence on the char yields....

  12. Thermomagnetic behavior of magnetic susceptibility – heating rate and sample size effects

    Directory of Open Access Journals (Sweden)

    Diana eJordanova

    2016-01-01

    Full Text Available Thermomagnetic analysis of magnetic susceptibility k(T was carried out for a number of natural powder materials from soils, baked clay and anthropogenic dust samples using fast (11oC/min and slow (6.5oC/min heating rates available in the furnace of Kappabridge KLY2 (Agico. Based on the additional data for mineralogy, grain size and magnetic properties of the studied samples, behaviour of k(T cycles and the observed differences in the curves for fast and slow heating rate are interpreted in terms of mineralogical transformations and Curie temperatures (Tc. The effect of different sample size is also explored, using large volume and small volume of powder material. It is found that soil samples show enhanced information on mineralogical transformations and appearance of new strongly magnetic phases when using fast heating rate and large sample size. This approach moves the transformation at higher temperature, but enhances the amplitude of the signal of newly created phase. Large sample size gives prevalence of the local micro- environment, created by evolving gases, released during transformations. The example from archeological brick reveals the effect of different sample sizes on the observed Curie temperatures on heating and cooling curves, when the magnetic carrier is substituted magnetite (Mn0.2Fe2.70O4. Large sample size leads to bigger differences in Tcs on heating and cooling, while small sample size results in similar Tcs for both heating rates.

  13. Distributed measurement of flow rate in conduits using heated fiber optic distributed temperature sensing

    Science.gov (United States)

    Sánchez, Raúl; Zubelzu, Sergio; Rodríguez-Sinobas, Leonor; Juana, Luis

    2016-04-01

    In some cases flow varies along conduits, such as in irrigated land drainage pipes and channels, irrigation laterals and others. Detailed knowledge of flow rate along the conduit makes possible analytical evaluation of water distribution and collection systems performance. Flow rate can change continuously in some systems, like in drainage pipes and channels, or abruptly, like in conduits bifurcations or emitter insertions. A heat pulse along the conduit makes possible to get flow rate from continuity and heat balance equations. Due to the great value of specific heat of water, temperature changes along conduit are smaller than the noise that involves the measurement process. This work presents a methodology that, dealing with the noise of distributed temperature measurements, leads to flow rate determination along pressurized pipes or open channel flows.

  14. Superheating and melting within aluminum core-oxide shell nanoparticles for a broad range of heating rates: multiphysics phase field modeling.

    Science.gov (United States)

    Hwang, Yong Seok; Levitas, Valery I

    2016-10-19

    The external surface of metallic particles is usually covered by a thin and strong oxide shell, which significantly affects superheating and melting of particles. The effects of geometric parameters and heating rate on characteristic melting and superheating temperatures and melting behavior of aluminum nanoparticles covered by an oxide shell were studied numerically. For this purpose, the multiphysics model that includes the phase field model for surface melting, a dynamic equation of motion, a mechanical model for stress and strain simulations, interface and surface stresses, and the thermal conduction model including thermoelastic and thermo-phase transformation coupling as well as transformation dissipation rate was formulated. Several nontrivial phenomena were revealed. In comparison with a bare particle, the pressure generated in a core due to different thermal expansions of the core and shell and transformation volumetric expansion during melting, increases melting temperatures with the Clausius-Clapeyron factor of 60 K GPa(-1). For the heating rates Q ≤ 10(9) K s(-1), melting temperatures (surface and bulk start and finish melting temperatures, and maximum superheating temperature) are independent of Q. For Q ≥ 10(12) K s(-1), increasing Q generally increases melting temperatures and temperature for the shell fracture. Unconventional effects start for Q ≥ 10(12) K s(-1) due to kinetic superheating combined with heterogeneous melting and geometry. The obtained results are applied to shed light on the initial stage of the melt-dispersion-mechanism of the reaction of Al nanoparticles. Various physical phenomena that promote or suppress melting and affect melting temperatures and temperature of the shell fracture for different heating-rate ranges are summarized in the corresponding schemes.

  15. Pyrolysis polygeneration of poplar wood: Effect of heating rate and pyrolysis temperature.

    Science.gov (United States)

    Chen, Dengyu; Li, Yanjun; Cen, Kehui; Luo, Min; Li, Hongyan; Lu, Bin

    2016-10-01

    The pyrolysis of poplar wood were comprehensively investigated at different pyrolysis temperatures (400, 450, 500, 550, and 600°C) and at different heating rates (10, 30, and 50°C/min). The results showed that BET surface area of biochar, the HHV of non-condensable gas and bio-oil reached the maximum values of 411.06m(2)/g, 14.56MJ/m(3), and 14.39MJ/kg, under the condition of 600°C and 30°C/min, 600°C and 50°C/min, and 550°C and 50°C/min, respectively. It was conducive to obtain high mass and energy yield of bio-oil at 500°C and higher heating rate, while lower pyrolysis temperature and heating rate contributed towards obtaining both higher mass yield and energy yield of biochar. However, higher pyrolysis temperature and heating rate contributed to obtain both higher mass yield and energy yield of the non-condensable gas. In general, compared to the heating rate, the pyrolysis temperature had more effect on the product properties. Copyright © 2016 Elsevier Ltd. All rights reserved.

  16. Effect of heating rate on the thermoluminescence and thermal properties of natural ulexite.

    Science.gov (United States)

    Topaksu, M; Correcher, V; Garcia-Guinea, J; Yüksel, M

    2014-10-31

    Boron-rich compounds are of interest in the nuclear industry because they exhibit a high neutron absorption cross section. The manufacture of these materials involves the application of thermal and chemical treatments. This paper focuses on the study of the effect of the heating rate (HR) in two thermal techniques, differential thermal analysis (DTA) and thermoluminescence (TL), performed on natural ulexite from Bigadiç-Balıkesir (Turkey). The TL measurements were performed at six different heating rates in the range of 25-240°Cmin(-1). The UV-blue TL emission of natural ulexite shifted toward higher temperatures with increasing heating rate, whereas the intensity decreased. The kinetic parameters of the ulexite (Ea=0.65(9) eV and s=1.22×10(12)s(-1)) were calculated using the variable heating rate method. DTA measurements performed in the range of 0.5-10°Cmin(-1) displayed similar behavior to that of the TL response, despite the differences in technique and HR values. The DTA results indicated that natural ulexite exhibits two endothermic peaks originating from different processes: (i) a phase transition between the pentahydrated ulexite phase and a triple-hydrated phase and (ii) dehydration, dehydroxylation and alkali and earth-alkali self-diffusion processes in the ulexite lattice. The main endothermic peak shifted from 160°C to 250°C as the heating rate was increased.

  17. Determination of Kinetic Parameters for Thermal Decomposition of Phenolic Ablative Materials by Multiple Heating Rate Method

    Science.gov (United States)

    1980-07-01

    the ratio method to analyze thermogravimetric data obtained for a urethane polymer. Baer, Hedges, Seader , Jayakar, and Wojcik6 heated samples of...reinforced polymers at heating rates up to 4200°C/min. The data were correlated by a numerical technique developed by Burningham and Seader .7 Friedman...Decomposition Through Thermogravimetric Analysis," Thermochimica Acta, No, 1, (1970), pp. 147-158. 6. A. D. Baer, J. H. Hedges, J. D. Seader , K. M. Jayakar

  18. Tuning of Heat Transfer Rate of Cobalt Manganese Ferrite Based Magnetic Fluids in Varying Magnetic Field

    Directory of Open Access Journals (Sweden)

    Margabandhu MARIMUTHU

    2017-08-01

    Full Text Available Magnetic fluids are the colloidal solutions containing suspended magnetic nanoparticles in carrier fluids. The present work analyzed the heat transfer characteristics of de-ionized water and transformer oil (base fluids based cobalt manganese ferrite (Co1-xMnxFe2O4 coated with oleic acid synthesized via co-precipitation technique magnetic fluids in  varying magnetic field. Experimental investigations were carried out to analyze the heat transfer property of synthesized magnetic fluids (MNF in varying magnetic field applied in perpendicular direction to the thermal gradient of magnetic fluids. The experimental results indicate that the magnetic fluids show enhancement in heat transfer rate than carrier fluids in absence of magnetic field and it shows decrement in heat transfer rate in presence of varying magnetic field. Thus, the results reveal that the heat transfer characteristics of cobalt manganese ferrite based magnetic fluids was tunable by controlling the direction and influence of magnetic field strength. This tunable heat transfer property of cobalt manganese ferrite based magnetic fluids could be applicable in heat transport phenomena of transformers and in microelectronic devices.DOI: http://dx.doi.org/10.5755/j01.ms.23.3.16662

  19. Standard Test Method for Measuring Heat Transfer Rate Using a Thin-Skin Calorimeter

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2005-01-01

    1.1 This test method covers the design and use of a thin metallic calorimeter for measuring heat transfer rate (also called heat flux). Thermocouples are attached to the unexposed surface of the calorimeter. A one-dimensional heat flow analysis is used for calculating the heat transfer rate from the temperature measurements. Applications include aerodynamic heating, laser and radiation power measurements, and fire safety testing. 1.2 Advantages 1.2.1 Simplicity of ConstructionThe calorimeter may be constructed from a number of materials. The size and shape can often be made to match the actual application. Thermocouples may be attached to the metal by spot, electron beam, or laser welding. 1.2.2 Heat transfer rate distributions may be obtained if metals with low thermal conductivity, such as some stainless steels, are used. 1.2.3 The calorimeters can be fabricated with smooth surfaces, without insulators or plugs and the attendant temperature discontinuities, to provide more realistic flow conditions for ...

  20. Heat rate curve approximation for power plants without data measuring devices

    Energy Technology Data Exchange (ETDEWEB)

    Poullikkas, Andreas [Electricity Authority of Cyprus, P.O. Box 24506, 1399 Nicosia (CY

    2012-07-01

    In this work, a numerical method, based on the one-dimensional finite difference technique, is proposed for the approximation of the heat rate curve, which can be applied for power plants in which no data acquisition is available. Unlike other methods in which three or more data points are required for the approximation of the heat rate curve, the proposed method can be applied when the heat rate curve data is available only at the maximum and minimum operating capacities of the power plant. The method is applied on a given power system, in which we calculate the electricity cost using the CAPSE (computer aided power economics) algorithm. Comparisons are made when the least squares method is used. The results indicate that the proposed method give accurate results.

  1. Heat rate curve approximation for power plants without data measuring devices

    Directory of Open Access Journals (Sweden)

    Andreas Poullikkas

    2012-01-01

    Full Text Available In this work, a numerical method, based on the one-dimensional finite difference technique, is proposed for the approximation of the heat rate curve, which can be applied for power plants in which no data acquisition is available. Unlike other methods in which three or more data points are required for the approximation of the heat rate curve, the proposed method can be applied when the heat rate curve data is available only at the maximum and minimum operating capacities of the power plant. The method is applied on a given power system, in which we calculate the electricity cost using the CAPSE (computer aided power economics algorithm. Comparisons are made when the least squares method is used. The results indicate that the proposed method give accurate results.

  2. Molecular dynamics simulations of aggregation of copper nanoparticles with different heating rates

    Science.gov (United States)

    Li, Qibin; Wang, Meng; Liang, Yunpei; Lin, Liyang; Fu, Tao; Wei, Peitang; Peng, Tiefeng

    2017-06-01

    Molecular dynamics simulations were employed to investigate the heating rates' effect on aggregation of two copper nanoparticles. The aggregation can be distinguished into three distinct regimes by the contacting and melting of nanoparticles. The nanoparticles contacting at a lower temperature during the sintering with lower heating rate, meanwhile, some temporary stacking fault exists at the contacting neck. The aggregation properties of the system, i.e. neck diameter, shrinkage ratio, potential energy, mean square displacement (MSD) and relative gyration radius, experience drastic changes due to the free surface annihilation. After the nanoparticles coalesced for a stable period, the shrinkage ratio, MSD, relative gyration radius and neck diameter of the system are dramatically changed during the melting process. It is shown that the shrinkage ratio and MSD have relative larger increasing ratio for a lower heating rate. While the evolution of the relative gyration radius and neck diameter is only sensitive to the temperature.

  3. Investigations on the heat transfer performance of edge-shaped finned-tubes

    Science.gov (United States)

    Wang, Xiao-wu; Wan, Zhen-ping; Tang, Yong

    2014-09-01

    The third generation enhanced heat transfer technologies, such as three-dimensional fin and dimple, are still important means of improving energy efficiency and will continue to be challenging issues. This paper concentrates on the analysis of the condensation heat transfer performance of an edge-shaped finned-tube fabricated by extrusion-ploughing process. Experimental results show that the overall heat transfer coefficient increases with increases of volumetric flow rate of cold water and heat flux whereas the shell side heat transfer coefficient decreases with volumetric flow rate and heat flux increasing. At the similar volumetric flow rate, the shell side heat transfer coefficient of the edge-shaped finned-tube is 4-6 times larger than that of the smooth tube. At the similar volumetric flow rate, the shell side heat transfer coefficient of edge-shaped finned-tube increases with ploughing depth increasing. At the same temperature difference between wall and vapor, the shell side heat transfer coefficient is also higher than what had been reported in the literature.

  4. Shortwave radiative heating rate profiles in hazy and clear atmosphere: a sensitivity study

    Science.gov (United States)

    Doppler, Lionel; Fischer, Jürgen; Ravetta, François; Pelon, Jacques; Preusker, René

    2010-05-01

    Aerosols have an impact on shortwave heating rate profiles (additional heating or cooling). In this survey, we quantify the impact of several key-parameters on the heating rate profiles of the atmosphere with and without aerosols. These key-parameters are: (1) the atmospheric model (tropical, midlatitude summer or winter, US Standard), (2) the integrated water vapor amount (IWV ), (3) the ground surface (flat and rough ocean, isotropic surface albedo for land), (4) the aerosol composition (dusts, soots or maritimes mixtures with respect to the OPAC-database classification), (5) the aerosol optical depth and (6) vertical postion, and (7) the single-scattering albedo (?o) of the aerosol mixture. This study enables us to evaluate which parameters are most important to take into account in a radiative energy budget of the atmosphere and will be useful for a future study: the retrieval of heating rates profiles from satellite data (CALIPSO, MODIS, MERIS) over the Mediterranean Sea. All the heating rates are computed by using the vector irradiances computed at each pressure level in the spectral interval 0.2 - 3.6μm (shortwave) by the 1D radiative transfer model for atmosphere and ocean: MOMO (Matrix-Operator MOdel) of the Institute for Space Science, FU Berlin 1

  5. Effects of heating rate on slow pyrolysis behavior, kinetic parameters and products properties of moso bamboo.

    Science.gov (United States)

    Chen, Dengyu; Zhou, Jianbin; Zhang, Qisheng

    2014-10-01

    Effects of heating rate on slow pyrolysis behaviors, kinetic parameters, and products properties of moso bamboo were investigated in this study. Pyrolysis experiments were performed up to 700 °C at heating rates of 5, 10, 20, and 30 °C/min using thermogravimetric analysis (TGA) and a lab-scale fixed bed pyrolysis reactor. The results show that the onset and offset temperatures of the main devolatilization stage of thermogravimetry/derivative thermogravimetry (TG/DTG) curves obviously shift toward the high-temperature range, and the activation energy values increase with increasing heating rate. The heating rate has different effects on the pyrolysis products properties, including biochar (element content, proximate analysis, specific surface area, heating value), bio-oil (water content, chemical composition), and non-condensable gas. The solid yields from the fixed bed pyrolysis reactor are noticeably different from those of TGA mainly because the thermal hysteresis of the sample in the fixed bed pyrolysis reactor is more thorough.

  6. A Solar Volumetric Receiver: Influence of Absorbing Cells Configuration on Device Thermal Performance

    Science.gov (United States)

    Yilbas, B. S.; Shuja, S. Z.

    2017-01-01

    Thermal performance of a solar volumetric receiver incorporating the different cell geometric configurations is investigated. Triangular, hexagonal, and rectangular absorbing cells are incorporated in the analysis. The fluid volume fraction, which is the ratio of the volume of the working fluid over the total volume of solar volumetric receiver, is introduced to assess the effect of cell size on the heat transfer rates in the receiver. In this case, reducing the fluid volume fraction corresponds to increasing cell size in the receiver. SiC is considered as the cell material, and air is used as the working fluid in the receiver. The Lambert's Beer law is incorporated to account for the solar absorption in the receiver. A finite element method is used to solve the governing equation of flow and heat transfer. It is found that the fluid volume fraction has significant effect on the flow field in the solar volumetric receiver, which also modifies thermal field in the working fluid. The triangular absorbing cell gives rise to improved effectiveness of the receiver and then follows the hexagonal and rectangular cells. The second law efficiency of the receiver remains high when hexagonal cells are used. This occurs for the fluid volume fraction ratio of 0.5.

  7. Heat and water rate transfer processes in the human respiratory tract at various altitudes.

    Science.gov (United States)

    Kandjov, I M

    2001-02-01

    The process of the respiratory air conditioning as a process of heat and mass exchange at the interface inspired air-airways surface was studied. Using a model of airways (Olson et al., 1970) where the segments of the respiratory tract are like cylinders with a fixed length and diameter, the corresponding heat transfer equations, in the paper are founded basic rate exchange parameters-convective heat transfer coefficient h(c)(W m(-2) degrees C(-1)) and evaporative heat transfer coefficient h(e)(W m(-2)hPa(-1)). The rate transfer parameters assumed as sources with known heat power are connected to airflow rate in different airways segments. Relationships expressing warming rate of inspired air due to convection, warming rate of inspired air due to evaporation, water diffused in the inspired air from the airways wall, i.e. a system of air conditioning parameters, was composed. The altitude dynamics of the relations is studied. Every rate conditioning parameter is an increasing function of altitude. The process of diffusion in the peripheral bronchial generations as a basic transfer process is analysed. The following phenomenon is in effect: the diffusion coefficient increases with altitude and causes a compensation of simultaneous decreasing of O(2)and CO(2)densities in atmospheric air. Due to this compensation, the diffusion in the peripheral generations with altitude is approximately constant. The elements of the human anatomy optimality as well as the established dynamics are discussed and assumed. The square form of the airways after the trachea expressed in terms of transfer supposes (in view of maximum contact surface), that a maximum heat and water exchange is achieved, i.e. high degree of air condition at fixed environmental parameters and respiration regime.

  8. 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

  9. Rate of heat transfer in polypropylene tubes in solar water heaters

    Energy Technology Data Exchange (ETDEWEB)

    Razavi, J.; Mahmoodi, M. [Sharif University of Technology, Tehran (Iran). Chemical Engineering Dept.; Riazi, M.R. [Kuwait Univ., Safat (Kuwait). Chemical Engineering Dept.

    2003-06-01

    A heat transfer rate was determined for polypropylene tubes in solar water heaters for the Reynolds number range 800-5600. Experiments were conducted in ambient temperatures of 34 to 37 {sup o}C. Data were correlated in the form of Nusselt numbers as: Nu=0.0015 Re{sup 0.75}Pr{sup 1/3} with correlation coefficient of 0.95. Such data can be used to predict heat transfer rates in a polypropylene solar heater in Tehran where the experiments were performed. An application of the results is shown in an example. (author)

  10. Products from the high temperature pyrolysis of RDF at slow and rapid heating rates

    OpenAIRE

    2015-01-01

    The high-temperature pyrolysis behaviour of a sample of refuse derived fuel (RDF) as a model of municipal solid waste (MSW) was investigated in a horizontal tubular reactor between 700 and 900 °C, at varying heating rates, and at an extended vapour residence time. Experiments were designed to evaluate the influence of process conditions on gas yields as well as gas and oil compositions. Pyrolysis of RDF at 800 °C and at rapid heating rate resulted in the gas yield with the highest CV of 24.8 ...

  11. Existing and Past Methods of Test and Rating Standards Related to Integrated Heat Pump Technologies

    Energy Technology Data Exchange (ETDEWEB)

    Reedy, Wayne R. [Sentech, Inc.

    2010-07-01

    This report evaluates existing and past US methods of test and rating standards related to electrically operated air, water, and ground source air conditioners and heat pumps, 65,000 Btu/hr and under in capacity, that potentiality incorporate a potable water heating function. Two AHRI (formerly ARI) standards and three DOE waivers were identified as directly related. Six other AHRI standards related to the test and rating of base units were identified as of interest, as they would form the basis of any new comprehensive test procedure. Numerous other AHRI and ASHRAE component test standards were also identified as perhaps being of help in developing a comprehensive test procedure.

  12. Effects of whole body heating on dynamic baroreflex regulation of heart rate in humans

    Science.gov (United States)

    Crandall, C. G.; Zhang, R.; Levine, B. D.

    2000-01-01

    The purpose of this project was to identify whether dynamic baroreflex regulation of heart rate (HR) is altered during whole body heating. In 14 subjects, dynamic baroreflex regulation of HR was assessed using transfer function analysis. In normothermic and heat-stressed conditions, each subject breathed at a fixed rate (0. 25 Hz) while beat-by-beat HR and systolic blood pressure (SBP) were obtained. Whole body heating significantly increased sublingual temperature, HR, and forearm skin blood flow. Spectral analysis of HR and SBP revealed that the heat stress significantly reduced HR and SBP variability within the high-frequency range (0.2-0.3 Hz), reduced SBP variability within the low-frequency range (0.03-0.15 Hz), and increased the ratio of low- to high-frequency HR variability (all P regulation of HR within the high-frequency range (from 1.04 +/- 0.06 to 0.54 +/- 0.6 beats. min(-1). mmHg(-1); P body heating reduced high-frequency dynamic baroreflex regulation of HR associated with spontaneous changes in blood pressure. Reduced vagal baroreflex regulation of HR may contribute to reduced orthostatic tolerance known to occur in humans during heat stress.

  13. Measurement of the heating rate of strongly coupled ^9Be^+ ions in a Penning trap

    Science.gov (United States)

    Jensen, M. J.; Hasegawa, T.; Bollinger, J. J.; Dubin, D. H. E.

    2003-10-01

    We have measured the temperature and heating rate of laser-cooled ^9Be^+ ions stored in a 4.5 T Penning trap. Up to ˜10^6 ^9Be^+ ions were laser cooled to mK temperatures where they form a crystal with a ˜20 μm interparticle spacing. We measured the ion temperature by Doppler laser spectroscopy on a single-photon transition. Immediately after turning off the cooling laser (t=0) we measured T ˜1 mK, which is close to the Doppler cooling limit. A slow heating rate of less than 100 mK/s is observed for t<200 ms, where t is the length of time the cooling laser is off. This is followed by a sudden, rapid heating on the order of 2 K in 0.1 s. The onset of the rapid heating occurs at the Coulomb coupling parameter of the solid-liquid phase transition, Γ ˜170. We therefore believe the rapid heating is a manifestation of the phase transition and will discuss our investigations into possible causes of this heating.

  14. A real-time heat strain risk classifier using heart rate and skin temperature.

    Science.gov (United States)

    Buller, Mark J; Latzka, William A; Yokota, Miyo; Tharion, William J; Moran, Daniel S

    2008-12-01

    Heat injury is a real concern to workers engaged in physically demanding tasks in high heat strain environments. Several real-time physiological monitoring systems exist that can provide indices of heat strain, e.g. physiological strain index (PSI), and provide alerts to medical personnel. However, these systems depend on core temperature measurement using expensive, ingestible thermometer pills. Seeking a better solution, we suggest the use of a model which can identify the probability that individuals are 'at risk' from heat injury using non-invasive measures. The intent is for the system to identify individuals who need monitoring more closely or who should apply heat strain mitigation strategies. We generated a model that can identify 'at risk' (PSI 7.5) workers from measures of heart rate and chest skin temperature. The model was built using data from six previously published exercise studies in which some subjects wore chemical protective equipment. The model has an overall classification error rate of 10% with one false negative error (2.7%), and outperforms an earlier model and a least squares regression model with classification errors of 21% and 14%, respectively. Additionally, the model allows the classification criteria to be adjusted based on the task and acceptable level of risk. We conclude that the model could be a valuable part of a multi-faceted heat strain management system.

  15. The dark energy survey Y1 supernova search: Survey strategy compared to forecasts and the photometric type Is SN volumetric rate

    Science.gov (United States)

    Fischer, John Arthur

    For 70 years, the physics community operated under the assumption that the expansion of the Universe must be slowing due to gravitational attraction. Then, in 1998, two teams of scientists used Type Ia supernovae to discover that cosmic expansion was actually acceler- ating due to a mysterious "dark energy." As a result, Type Ia supernovae have become the most cosmologically important transient events in the last 20 years, with a large amount of effort going into their discovery as well as understanding their progenitor systems. One such probe for understanding Type Ia supernovae is to use rate measurements to de- termine the time delay between star formation and supernova explosion. For the last 30 years, the discovery of individual Type Ia supernova events has been accelerating. How- ever, those discoveries were happening in time-domain surveys that probed only a portion of the redshift range where expansion was impacted by dark energy. The Dark Energy Survey (DES) is the first project in the "next generation" of time-domain surveys that will discovery thousands of Type Ia supernovae out to a redshift of 1.2 (where dark energy be- comes subdominant) and DES will have better systematic uncertainties over that redshift range than any survey to date. In order to gauge the discovery effectiveness of this survey, we will use the first season's 469 photometrically typed supernovee and compare it with simulations in order to update the full survey Type Ia projections from 3500 to 2250. We will then use 165 of the 469 supernovae out to a redshift of 0.6 to measure the supernovae rate both as a function of comoving volume and of the star formation rate as it evolves with redshift. We find the most statistically significant prompt fraction of any survey to date (with a 3.9? prompt fraction detection). We will also reinforce the already existing tension in the measurement of the delayed fraction between high (z > 1.2) and low red- shift rate measurements, where we find no

  16. Effect of the heating rate on the morphology of the pyrolytic char from hazelnut shell

    Energy Technology Data Exchange (ETDEWEB)

    Hanzade, H.A.; Serdar, Y. [Istanbul Technical Univ., Istanbul (Turkey). Faculty of Chemical and Metallurgical Engineering

    2008-07-01

    Although biomass chars have a high potential for use in various applications, their performance is directly related to the chemical and the physical properties of the chars. The surface area, porosity, pore size distribution, and density are the physical properties that determine the suitability of the chars to be used. Hazelnut shells are touted as being an extremely appropriate feedstock for high quality pyrolytic char, but the working conditions under which char is obtained have significant influence on the char structure and its properties, such as the thermal reactivity. Therefore, effects of the various parameters on the char structure must be considered. In this context, the present study focused on the physical changes that occur in char as a result of different heating rates during the pyrolysis of hazelnut shells. The effects of the heating rate on the structure of the pyrolytic char obtained from ground hazelnut shells under six different heating rate conditions were investigated. The hazelnut shell was burned in a thermogravimetric analyzer (TGA) under nitrogen flow. Non-isothermal heating was performed from ambient to 900 degrees C and held at this temperature until no further mass loss occurred. The changes in char morphology were studied with respect to the heating rate during charring. Scanning electron microscopy (SEM) was used with each char sample to determine the effect of heating rate. The dominant inorganic phases found in hazelnut shells were found to survive in the char. It was concluded that the high lignin content found in the char played a critical role in the decomposition mechanism. 3 refs., 2 tabs., 2 figs.

  17. Heat shock response in yeast involves changes in both transcription rates and mRNA stabilities.

    Directory of Open Access Journals (Sweden)

    Laia Castells-Roca

    Full Text Available We have analyzed the heat stress response in the yeast Saccharomyces cerevisiae by determining mRNA levels and transcription rates for the whole transcriptome after a shift from 25 °C to 37 °C. Using an established mathematical algorithm, theoretical mRNA decay rates have also been calculated from the experimental data. We have verified the mathematical predictions for selected genes by determining their mRNA decay rates at different times during heat stress response using the regulatable tetO promoter. This study indicates that the yeast response to heat shock is not only due to changes in transcription rates, but also to changes in the mRNA stabilities. mRNA stability is affected in 62% of the yeast genes and it is particularly important in shaping the mRNA profile of the genes belonging to the environmental stress response. In most cases, changes in transcription rates and mRNA stabilities are homodirectional for both parameters, although some interesting cases of antagonist behavior are found. The statistical analysis of gene targets and sequence motifs within the clusters of genes with similar behaviors shows that both transcriptional and post-transcriptional regulons apparently contribute to the general heat stress response by means of transcriptional factors and RNA binding proteins.

  18. Study of the Al-Si-X system by different cooling rates and heat treatment

    Directory of Open Access Journals (Sweden)

    Miguel Angel Suarez

    2012-10-01

    Full Text Available The solidification behavior of the Al-12.6% Si (A1, the hypereutectic Al-20%Si (A2 and the Al-20%Si-1.5% Fe-0.5%Mn (A3 (in wt. (% alloys, at different cooling rates is reported and discussed. The cooling rates ranged between 0.93 °C/s and 190 °C/s when cast in sand and copper wedge-shaped molds, respectively. A spheroidization heat treatment was carried out to the alloys in the as-cast condition at 540 °C for 11 hours and quench in water with a subsequent heat treatment at 170 °C for 5 hours with the purpose of improving the mechanical properties. The samples were characterized by optical microscopy, scanning electron microscopy and mechanically by tensile test, in order to evaluate the response of the heat treatment on the different starting microstructures and mechanical properties. It was found that alloys cooled at rates greater than 10.8 °C/s had a smaller particle size and better distribution, also showed a greater response to spheroidization heat treatment of all silicon (Si phases. The spheroidization heat treatment caused an increase in the ultimate tensile stress (UTS and elongation when compared with the alloys in the as-cast condition. The highest UTS value of 174 MPa was obtained for the (A1 alloy.

  19. Characterization of heat waves affecting mortality rates of broilers between 29 days and market age

    Directory of Open Access Journals (Sweden)

    MM Vale

    2010-12-01

    Full Text Available Climate may affect broiler production, especially where there are heat waves, which may cause high mortality rates due to the heat stress. Heat wave prediction and characterization may allow early mitigation actions to be taken. Data Mining is one of the tools used for such a characterization, particularly when a large number of variables is involved. The objective of this study was to classify heat waves that promote broiler chicken mortality in poultry houses equipped with minimal environmental control. A single day of heat, a heat-shock day, is capable of producing high broiler mortality. In poultry houses equipped with fans and evaporative cooling, the characterization of heat waves affecting broiler mortality between 29 days of age and market age presented 89.34% Model Accuracy and 0.73 Class Precision for high mortality. There was no influence on high mortality (HM of birds between 29 and 31 days of age. Maximum temperature humidity index (THI above 30.6 ºC was the main characteristic of days when there was a heat wave, causing high mortality in broilers older than 31 days. The high mortality of broilers between 31 and 40 days of age occurred when maximum THI was above 30.6 ºC and maximum temperature of the day was above 34.4 ºC. There were two main causes of high mortality of broilers older than 40 days: 1 maximum THI above 30.6 ºC and minimum THI equal or lower than 15.5 ºC; 2 maximum THI above 30.6 ºC, minimum THI lower than 15.5 ºC, and the time of maximum temperature later than 15:00h. The heat wave influence on broiler mortality lasted an average of 2.7 days.

  20. Average Heating Rate of Hot Atmospheres in Distant Galaxy Clusters by Radio AGN: Evidence for Continuous AGN Heating

    Science.gov (United States)

    Ma, Cheng-Jiun; McNamara, B.; Nulsen, P.; Schaffer, R.

    2011-09-01

    X-ray observations of nearby clusters and galaxies have shown that energetic feedback from AGN is heating hot atmospheres and is probably the principal agent that is offsetting cooling flows. Here we examine AGN heating in distant X-ray clusters by cross correlating clusters selected from the 400 Square Degree X-ray Cluster survey with radio sources in the NRAO VLA Sky Survey. The jet power for each radio source was determined using scaling relations between radio power and cavity power determined for nearby clusters, groups, and galaxies with atmospheres containing X-ray cavities. Roughly 30% of the clusters show radio emission above a flux threshold of 3 mJy within the central 250 kpc that is presumably associated with the brightest cluster galaxy. We find no significant correlation between radio power, hence jet power, and the X-ray luminosities of clusters in redshift range 0.1 -- 0.6. The detection frequency of radio AGN is inconsistent with the presence of strong cooling flows in 400SD, but cannot rule out the presence of weak cooling flows. The average jet power of central radio AGN is approximately 2 10^{44} erg/s. The jet power corresponds to an average heating of approximately 0.2 keV/particle for gas within R_500. Assuming the current AGN heating rate remained constant out to redshifts of about 2, these figures would rise by a factor of two. Our results show that the integrated energy injected from radio AGN outbursts in clusters is statistically significant compared to the excess entropy in hot atmospheres that is required for the breaking of self-similarity in cluster scaling relations. It is not clear that central AGN in 400SD clusters are maintained by a self-regulated feedback loop at the base of a cooling flow. However, they may play a significant role in preventing the development of strong cooling flows at early epochs.

  1. Study on release rate of latent heat in Czochralski silicon growth

    Institute of Scientific and Technical Information of China (English)

    REN Bingyan; YANG Jiankun; LI Yanlin; LIU Xiaoping; WANG Minhua

    2006-01-01

    The pulling rate in czochralski silicon (CZSi) growth is important for reducing the cost of solar cell.In this paper, double-heater, heat shield and composite argon duct system were introduced in the Ф450 mm hot zone of a Czochralski furnace.The pulling rate under different thermal system was recorded in experiments.Argon flow and temperature fields were simulated by finite element method(FEM).Experimental results and numerical simulation indicate that double-heater and composite argon duct system can enhance obviously the release rate of latent heat.In Φ 200 mm Czochralski silicon (CZSi) growth, average pulling rate can increase from 0.6 mm·min-1 in the conventional hot zone to 0.8 mm·min-1 in the modified hot zone.

  2. Heat and mass transfer rates during flow of dissociated hydrogen gas over graphite surface

    Science.gov (United States)

    Nema, V. K.; Sharma, O. P.

    1986-01-01

    To improve upon the performance of chemical rockets, the nuclear reactor has been applied to a rocket propulsion system using hydrogen gas as working fluid and a graphite-composite forming a part of the structure. Under the boundary layer approximation, theoretical predictions of skin friction coefficient, surface heat transfer rate and surface regression rate have been made for laminar/turbulent dissociated hydrogen gas flowing over a flat graphite surface. The external stream is assumed to be frozen. The analysis is restricted to Mach numbers low enough to deal with the situation of only surface-reaction between hydrogen and graphite. Empirical correlations of displacement thickness, local skin friction coefficient, local Nusselt number and local non-dimensional heat transfer rate have been obtained. The magnitude of the surface regression rate is found low enough to ensure the use of graphite as a linear or a component of the system over an extended period without loss of performance.

  3. Effect of pyrolysis pressure and heating rate on radiata pine char structure and apparent gasification reactivity

    Energy Technology Data Exchange (ETDEWEB)

    E. Cetin; R. Gupta; B. Moghtaderi [University of Newcastle, Callaghan, NSW (Australia). Discipline of Chemical Engineering, Faculty of Engineering and Built Environment, School of Engineering

    2005-07-01

    The knowledge of biomass char gasification kinetics has considerable importance in the design of advanced biomass gasifiers, some of which operate at high pressure. The char gasification kinetics themselves are influenced by char structure. In this study, the effects of pyrolysis pressure and heating rate on the char structure were investigated using scanning electron microscopy (SEM) analysis, digital cinematography, and surface area analysis. Char samples were prepared at pressures between 1 and 20 bar, temperatures ranging from 800 to 1000{degree}C, and heating rates between 20 and 500{degree}C/s. Our results indicate that pyrolysis conditions have a notable impact on the biomass char morphology. Pyrolysis pressure, in particular, was found to influence the size and the shape of char particles while high heating rates led to plastic deformation of particles (i.e. melting) resulting in smooth surfaces and large cavities. The global gasification reactivities of char samples were also determined using thermogravimetric analysis (TGA) technique. Char reactivities were found to increase with increasing pyrolysis heating rates and decreasing pyrolysis pressure. 22 refs., 8 figs., 2 tabs.

  4. Characterizing the effects of scale and heating rate on micro-scale explosive ignition criteria.

    Energy Technology Data Exchange (ETDEWEB)

    Hafenrichter, Everett Shingo; Pahl, Robert J.

    2005-01-01

    Laser diode ignition experiments were conducted in an effort to characterize the effects of scale and heating rate on micro-scale explosive ignition criteria. Over forty experiments were conducted with various laser power densities and laser spot sizes. In addition, relatively simple analytical and numerical calculations were performed to assist with interpretation of the experimental data and characterization of the explosive ignition criteria.

  5. Heating Rate Effect on the Activation of Viscoelastic Relaxation in Silicate Glasses

    Science.gov (United States)

    Naji, Mohamed; Piazza, Francesco; Guimbretière, Guillaume; Canizarès, Aurèlien; Ory, Sandra; Vaills, Yann

    Here we present a direct investigation of the heating rate effect on structural relaxation of sodium silicate glass near the glass transition by means of differential scanning calorimetry, and show the sensitivity of Brillouin light spectroscopy to the dynamic of structural relaxation in the medium range order (∼100 nm).

  6. The influence of SPS heating rates on the synthesis reaction of tantalum diboride

    Directory of Open Access Journals (Sweden)

    Jolanta Laszkiewicz-Łukasik

    2016-07-01

    Full Text Available TaB2 is a material from the Ultra High Temperature Ceramics group and is rather unexplored because it is difficult to procure the raw materials and to densify TaB2. Using SPS technique to realize reactive sintering processes of powders mixture according to the reaction Ta + 2B → TaB2 makes it possible to achieve TaB2 in one technological step. The aim of the study was to determine the influence of heating rates on the synthesis reaction and on the multistage densification mechanisms during SPS processes. The mixture was sintered at constant parameters of 2200 °C, 48 MPa for 5 min with the usage of heating rates from 50 °C/min up to 400 °C/min. The densification processes were studied through analyzing the shrinkage of powder compacts during SPS (Spark Plasma Sintering processes. The comparison of the densification curves indicates that the reactions do not proceed completely at slow heating rates. Namely, too low heating rates contribute to the sintering of tantalum before the synthesis reaction and demonstrate the presence of boron in liquid state. The best material obtained in this study has Young's modulus 571 GPa, Vickers hardness 20.7 GPa (HV1 and indentation fracture toughness KIC 4.7 MPa m1/2.

  7. Respiration Rate Predictive Equation and Effective Heat Stress Relief Ways for Hanwoo Steers

    OpenAIRE

    Gutierrez, Winson-Montanez; Oh, Taek-Kuen; Kim, Dong-Hyeok; Lee, Jin-Ju; Kim, Suk; Min, Wong; Lee, Seung-Joo; Kim, Byeong-Woo; Chang, Hong-Hee; Chikushi, Jiro

    2012-01-01

    Normalizing respiration rate in heat–stress challenged cattle during summer season is very important. In this study, we investigated the contribution of different thermal factors such as skin temperature, dew–point temperature, solar radiation, dry–bulb temperature and wind speed on its influence to the respiration rate dynamics of 45 Hanwoo steers in 2010. Secondly, the heat insulation efficiencies of the three kinds of roofing materials such as sandwich panel (SP), master panel (MP), and fi...

  8. Image fusion analysis of volumetric changes after interstitial low-dose-rate iodine-125 irradiation of supratentorial low-grade gliomas.

    Science.gov (United States)

    Julow, Jeno; Major, Tibor; Mangel, László; Bajzik, Gábor; Viola, Arpad

    2007-04-01

    The aim of this study was to compare the volumes of tumor necrosis, reactive zone and edema with the three-dimensional dose distributions after brachytherapy treatments of gliomas. The investigation was performed an average of 14.2 months after low-dose-rate (125)I interstitial irradiation of 25 inoperable low-grade gliomas. The prescribed dose was 50-60 Gy to the tumor surface. Dose planning and image fusion were performed with the BrainLab-Target 1.19 software. In the CT/ MRI images, the "triple ring" (tumor necrosis, reactive ring and edema) developing after the interstitial irradiation of the brain tumors was examined. The images with the triple ring were fused with the planning images, and the isodose curves were superimposed on them. The volumes of the three regions were measured. The average dose at the necrosis border was determined from the isodose distribution. For quantitative assessment of the dose distributions, the dose nonuniformity ratio (DNR), homogeneity index (HI), coverage index (CI) and conformal index (COIN) were calculated. The relative volumes of the different parts of the triple ring after the interstitial irradiation compared to the reference dose volume were the following: necrosis, 40.9%, reactive zone, 47.1%, and edema, 367%. The tumor necrosis developed at 79.1 Gy on average. The average DNR, HI, CI and COIN were 0.45, 0.24, 0.94 and 0.57, respectively. The image fusion analysis of the volume of tumor necrosis, reactive ring and edema caused by interstitial irradiation and their correlation with the dose distribution provide valuable information for patient follow-up, treatment options, and effects and side effects of radio therapy.

  9. Estimation of lava flow field volumes and volumetric effusion rates from airborne radar profiling and other data: Monitoring of the Nornahraun (Holuhraun) 2014/15 eruption in Iceland

    Science.gov (United States)

    Dürig, Tobias; Gudmundsson, Magnús; Högnadóttir, Thordís; Jónsdóttir, Ingibjörg; Gudbjörnsson, Snaebjörn; Lárusson, Örnólfur; Höskuldsson, Ármann; Thordarson, Thorvaldur; Riishuus, Morten; Magnússon, Eyjólfur

    2015-04-01

    . We discuss the used methods and their range of application in detail, present the resulting volume estimates of the new lava field and pinpoint the implications with emphasis on the temporal evolution of its effusion rate.

  10. Waste Heat to Power Market Assessment

    Energy Technology Data Exchange (ETDEWEB)

    Elson, Amelia [ICF International, Fairfax, VA (United States); Tidball, Rick [ICF International, Fairfax, VA (United States); Hampson, Anne [ICF International, Fairfax, VA (United States)

    2015-03-01

    Waste heat to power (WHP) is the process of capturing heat discarded by an existing process and using that heat to generate electricity. In the industrial sector, waste heat streams are generated by kilns, furnaces, ovens, turbines, engines, and other equipment. In addition to processes at industrial plants, waste heat streams suitable for WHP are generated at field locations, including landfills, compressor stations, and mining sites. Waste heat streams are also produced in the residential and commercial sectors, but compared to industrial sites these waste heat streams typically have lower temperatures and much lower volumetric flow rates. The economic feasibility for WHP declines as the temperature and flow rate decline, and most WHP technologies are therefore applied in industrial markets where waste heat stream characteristics are more favorable. This report provides an assessment of the potential market for WHP in the industrial sector in the United States.

  11. An experimental study of a three-phase, direct-contact heat exchanger

    Energy Technology Data Exchange (ETDEWEB)

    Siqueiros, J.; Bonilla, O. [Unidad Energias No-Convencionales, Div. Energias Alternas e Informatica, Cuernavaca (Mexico)

    1999-05-01

    An experimental pilot scale three-phase, direct-contact heat exchanger was constructed and tested. Experiments were performed using normal pentane as the dispersed phase and water as the continuous phase. The inlet water temperatures ranged from 75 to 88degC, and the inlet pentane temperatures varied from 23 to 38degC. The volumetric heat transfer coefficient, hold-up and heat flow-rate are functions of pentane mass flow-rate. For high pentane/water volumetric flow ratios flooding was reached. Before reaching flooding conditions, accumulation of liquid pentane at the top of the active volume was found. The experimental volumetric heat transfer coefficient values are on average 30% greater than those estimated with the correlation previously proposed by Jacobs. (Author)

  12. Effect of low and high heating rates on reaction path of Ni(V)/Al multilayer

    Energy Technology Data Exchange (ETDEWEB)

    Maj, Łukasz, E-mail: l.maj@imim.pl [Institute of Metallurgy and Materials Science, Polish Academy of Sciences, 25 Reymonta St., 30-059 Kraków (Poland); Morgiel, Jerzy; Szlezynger, Maciej [Institute of Metallurgy and Materials Science, Polish Academy of Sciences, 25 Reymonta St., 30-059 Kraków (Poland); Bała, Piotr; Cios, Grzegorz [AGH University of Science and Technology, Academic Centre for Materials and Nanotechnology, 30 Kawiory St., 30-055 Kraków (Poland)

    2017-06-01

    The effect of heating rates of Ni(V)/Al NanoFoils{sup ®} was investigated with transmission electron microscopy (TEM). The Ni(V)/Al were subjected to heating by using differential scanning calorimetry (DSC), in-situ TEM or electric pulse. Local chemical analysis was carried out using energy dispersive X-ray spectroscopy (EDS). Phase analysis was done with X-ray diffractions (XRD) and selected area electron diffractions (SAED). The experiments showed that slow heating in DSC results in development of separate exothermic effects at ∼230 °C, ∼280 °C and ∼390 °C, corresponding to precipitation of Al{sub 3}Ni, Al{sub 3}Ni{sub 2} and NiAl phases, respectively, i.e. like in vanadium free Ni/Al multilayers. Further heating to 700 °C allowed to obtain a single phase NiAl foil. The average grain size (g.s.) of NiAl phase produced in the DSC heat treated foil was comparable with the Ni(V)/Al multilayer period (∼50 nm), whereas in the case of reaction initiated with electric pulse the g.s. was in the micrometer range. Upon slow heating vanadium tends to segregate to zones parallel to the original multilayer internal interfaces, while in SHS process vanadium-rich phases precipitates at grain boundaries of the NiAl phase. - Highlights: • Peaks in DSC heating of Ni(V)/Al were explained by in-situ TEM observations. • Nucleation of Al{sub 3}Ni, Al{sub 3}Ni{sub 2} and NiAl at slow heating of Ni(V)/Al was documented. • Near surface NiAl obtained from NanoFoil show Ag precipitates at grain boundaries.

  13. The influence of spectral solar irradiance data on stratospheric heating rates during the 11 year solar cycle

    OpenAIRE

    Oberländer, S.; Langematz, U.; Matthes, Katja; Kunze, M; A. Kubin; J. Harder; N. A. Krivova; Solanki, S. K.; J. Pagaran; Weber, M.

    2012-01-01

    Heating rate calculations with the FUBRad shortwave (SW) radiation parameterization have been performed to examine the effect of prescribed spectral solar fluxes from the NRLSSI, MPS and IUP data sets on SW heating rates over the 11 year solar cycle 22. The corresponding temperature response is derived from perpetual January General Circulation Model (GCM) simulations with prescribed ozone concentrations. The different solar flux input data sets induce clear differences in SW heating rates at...

  14. On-line corrosion monitoring in geothermal district heating systems. I. General corrosion rates

    DEFF Research Database (Denmark)

    Richter, S.; Hilbert, Lisbeth Rischel; Thorarinsdottir, R.I.

    2006-01-01

    General corrosion rates in the geothermal district heating systems in Iceland are generally low, of the magnitude 1 mu m/y. The reason is high pH (9.5), low-conductivity (200 mu m/y) and negligible dissolved oxygen. The geothermal hot water is either used directly from source or to heat up cold...... ground water. The fluid naturally contains sulphide, which helps keeping the fluid oxygen-free but complicates the electrochemical environment. In this research on-line techniques for corrosion monitoring were tested and evaluated in this medium. Electrochemical methods worked well as long as frequency...

  15. Smoke Movement in an Atrium with a Fire with Low Rate of Heat Release

    DEFF Research Database (Denmark)

    Nielsen, Peter V.; Brohus, Henrik; Petersen, A. J.

    2008-01-01

    Results from small-scale experiments on smoke movement in an atrium are given, both with and without a vertical temperature gradient, and expressions for the smoke movement are developed on the basis of these experiments. Comparisons with a general analytical expression used for calculating...... the height to the location of the smoke layer are given. Furthermore, the paper discusses the air movement in a typical atrium exposed to different internal and external heat loads to elaborate on the use of the "flow element" expressions developed for smoke movement from a fire with a low rate of heat...

  16. The Effect of Particle Concentration on the Heating Rate of Ferrofluids for Magnetic Hyperthermia

    Directory of Open Access Journals (Sweden)

    Malaescu I.

    2015-12-01

    Full Text Available The complex magnetic susceptibility χ(f = χ′(f - i χ″(f, of a ferrofluid sample with magnetite particles dispersed in kerosene and stabilized with oleic acid, over the range 0.1 GHz to 6 GHz, was determined. The initial sample has been successively diluted with kerosene (with a dilution rate of 2/3, thus obtaining further three samples. Using the complex magnetic susceptibility measurements of each sample, the frequency field and particle concentration dependencies of the heating rate of the ferrofluid samples, were analyzed. The results show the possibility of using the heating rate of ferrofluid samples with different particle concentrations, in hyperthermia applications.

  17. Evaluation of induced activity, decay heat and dose rate distribution after shutdown in ITER

    Energy Technology Data Exchange (ETDEWEB)

    Maki, Koichi [Hitachi Ltd., Ibaraki (Japan). Hitachi Research Lab.; Satoh, Satoshi; Hayashi, Katsumi; Yamada, Koubun; Takatsu, Hideyuki; Iida, Hiromasa

    1997-03-01

    Induced activity, decay heat and dose rate distributions after shutdown were estimated for 1MWa/m{sup 2} operation in ITER. The activity in the inboard blanket one day after shutdown is 1.5x10{sup 11}Bq/cm{sup 3}, and the average decay heating rate 0.01w/cm{sup 3}. The dose rate outside the 120cm thick concrete biological shield is two order higher than the design criterion of 5{mu}Sv/h. This indicates that the biological shield thickness should be enhanced by 50cm in concrete, that is, total thickness 170cm for workers to enter the reactor room and to perform maintenance. (author)

  18. Heat Source Neutron Emission Rate Reduction Studies - Water Induced HF Liberation

    Science.gov (United States)

    Matonic, John; Brown, John; Foltyn, Liz; Garcia, Lawrence; Hart, Ron; Herman, David; Huling, Jeff; Pansoy-Hjelvik, M. E. Lisa; Sandoval, Fritz; Spengler, Diane

    2004-02-01

    Plutonium-238 oxide (238PuO2) is used in the fabrication of general purpose heat sources (GPHS) or light-weight radioisotope heater units (LWRHUs). The heat sources supply the thermal energy used in radioisotope thermoelectric generators to power spacecraft for deep space missions and to heat critical components in the cold environs of space. Los Alamos National Laboratory has manufactured heat sources for approximately two decades. The aqueous purification of 238PuO2 is required, due to rigorous total Pu-content, actinide and non-actinide metal impurity, and neutron emission rate specifications. The 238PuO2 aqueous purification process is a new capability at Los Alamos National Laboratory as previously, aqueous purified 238PuO2 occurred at other DOE complexes. The Pu-content and actinide and non-actinide metal impurity specifications are met well within specification in the Los Alamos process, though reduction in neutron emission rates have been challenging. High neutron emission rates are typically attributed to fluoride content in the oxide. The alpha decay from 238Pu results in α,n reactions with light elements such as 17O, 18O, and 19F resulting in high neutron emission rates in the purified 238PuO2. Simple 16O-exchange takes care of the high NER due to 17O, and 18O. A new method to reduce the NER due to 19F in the purified 238PuO2 is presented in this paper. The method involves addition of water to purified 238PuO2, followed by heating to remove the water and liberating fluoride as HF.

  19. Artificial Neural Networks-Based Software for Measuring Heat Collection Rate and Heat Loss Coefficient of Water-in-Glass Evacuated Tube Solar Water Heaters.

    Science.gov (United States)

    Liu, Zhijian; Liu, Kejun; Li, Hao; Zhang, Xinyu; Jin, Guangya; Cheng, Kewei

    2015-01-01

    Measurements of heat collection rate and heat loss coefficient are crucial for the evaluation of in service water-in-glass evacuated tube solar water heaters. However, conventional measurement requires expensive detection devices and undergoes a series of complicated procedures. To simplify the measurement and reduce the cost, software based on artificial neural networks for measuring heat collection rate and heat loss coefficient of water-in-glass evacuated tube solar water heaters was developed. Using multilayer feed-forward neural networks with back-propagation algorithm, we developed and tested our program on the basis of 915 measured samples of water-in-glass evacuated tube solar water heaters. This artificial neural networks-based software program automatically obtained accurate heat collection rate and heat loss coefficient using simply "portable test instruments" acquired parameters, including tube length, number of tubes, tube center distance, heat water mass in tank, collector area, angle between tubes and ground and final temperature. Our results show that this software (on both personal computer and Android platforms) is efficient and convenient to predict the heat collection rate and heat loss coefficient due to it slow root mean square errors in prediction. The software now can be downloaded from http://t.cn/RLPKF08.

  20. Effects of Adiabatic Heating on the High Strain Rate Deformation of Polymer Matrix Composites

    Science.gov (United States)

    Sorini, Chris; Chattopadhyay, Aditi; Goldberg, Robert K.

    2017-01-01

    Polymer matrix composites (PMCs) are increasingly being used in aerospace structures that are expected to experience complex dynamic loading conditions throughout their lifetime. As such, a detailed understanding of the high strain rate behavior of the constituents, particularly the strain rate, temperature, and pressure dependent polymer matrix, is paramount. In this paper, preliminary efforts in modeling experimentally observed temperature rises due to plastic deformation in PMCs subjected to dynamic loading are presented. To this end, an existing isothermal viscoplastic polymer constitutive formulation is extended to model adiabatic conditions by incorporating temperature dependent elastic properties and modifying the components of the inelastic strain rate tensor to explicitly depend on temperature. It is demonstrated that the modified polymer constitutive model is capable of capturing strain rate and temperature dependent yield as well as thermal softening associated with the conversion of plastic work to heat at high rates of strain. The modified constitutive model is then embedded within a strength of materials based micromechanics framework to investigate the manifestation of matrix thermal softening, due to the conversion of plastic work to heat, on the high strain rate response of a T700Epon 862 (T700E862) unidirectional composite. Adiabatic model predictions for high strain rate composite longitudinal tensile, transverse tensile, and in-plane shear loading are presented. Results show a substantial deviation from isothermal conditions; significant thermal softening is observed for matrix dominated deformation modes (transverse tension and in-plane shear), highlighting the importance of accounting for the conversion of plastic work to heat in the polymer matrix in the high strain rate analysis of PMC structures.

  1. Effects of Heating Rate on the Process Parameters of Superplastic Forming for Zr55Cu30Al10Ni5

    Institute of Scientific and Technical Information of China (English)

    YANG Fan; SHI Tielin; LIAO Guanglan

    2014-01-01

    We investigated the effects of heating rate on the process parameters of superplastic forming for Zr55Cu30Al10Ni5 by differential scanning calorimetry. The continuous heating and isothermal annealing analyses suggested that the temperatures of glass transition and onset crystallization are heating rate-dependent in the supercooled liquid region. Then, the time-temperature-transformation diagram under different heating rates indicates that increasing the heating rate can lead to an increase of the incubation time at the same anneal temperature in the supercooled liquid region. Based on the Arrhenius relationship, we discovered that the incubation time increases by 1.08-1.11 times with double increase of the heating rate at the same anneal temperature, and then verified it by the data of literatures and the experimental results. The obtained curve of the max available incubation time reveals that the incubation time at a certain anneal temperature in the supercooled liquid region is not infinite, and will increase with increasing heating rate until this temperature shifts out of the supercooled liquid region because of exceeding critical heating rate. It is concluded that heating rate must be an important processing parameter of superplastic forming for Zr55Cu30Al10Ni5.

  2. EXPERIMENTAL STUDY OF MEASUREMENT FOR DISSIPATION RATE SCALING EXPONENT IN HEATED WALL TURBULENCE

    Institute of Scientific and Technical Information of China (English)

    姜楠; 王玉春; 舒玮; 王振东

    2002-01-01

    Experimental investigations have been devoted to the study of scaling law of coarse-grained dissipation rate structure function for velocity and temperature fluctuation of non-isotropic and inhomogeneous turbulent flows at moderate Reynolds number. Much attention has been paid to the case of turbulent boundary layer, which is typically the nonistropic and inhomogeneous trubulence because of the dynamically important existence of organized coherent structure burst process in the near wall region. Longitudinal velocity and temperature have been measured at different vertical positions in turbulent boundary layer over a heated and unheated flat plate in a wind tunnel using hot wire anemometer. The influence of non-isotropy and inhomogeneity and heating the wall on the scaling law of the dissipation rate structure function is studied because of the existence of organized coherent structure burst process in the near wall region. The scaling law of coarse-grained dissipation rate structure function is found to be independent of the mean velocity shear strain and the heating wall boundary condition. The scaling law of the dissipation rate structure function is verified to be in agreement with the hierarchical structure model that has been verified valid for isotropic and homogeneous turbulence.

  3. Scaling of heat production by thermogenic flowers: limits to floral size and maximum rate of respiration.

    Science.gov (United States)

    Seymour, Roger S

    2010-09-01

    Effect of size of inflorescences, flowers and cones on maximum rate of heat production is analysed allometrically in 23 species of thermogenic plants having diverse structures and ranging between 1.8 and 600 g. Total respiration rate (, micromol s(-1)) varies with spadix mass (M, g) according to in 15 species of Araceae. Thermal conductance (C, mW degrees C(-1)) for spadices scales according to C = 18.5M(0.73). Mass does not significantly affect the difference between floral and air temperature. Aroids with exposed appendices with high surface area have high thermal conductance, consistent with the need to vaporize attractive scents. True flowers have significantly lower heat production and thermal conductance, because closed petals retain heat that benefits resident insects. The florets on aroid spadices, either within a floral chamber or spathe, have intermediate thermal conductance, consistent with mixed roles. Mass-specific rates of respiration are variable between species, but reach 900 nmol s(-1) g(-1) in aroid male florets, exceeding rates of all other plants and even most animals. Maximum mass-specific respiration appears to be limited by oxygen delivery through individual cells. Reducing mass-specific respiration may be one selective influence on the evolution of large size of thermogenic flowers.

  4. Torrefaction of invasive alien plants: Influence of heating rate and other conversion parameters on mass yield and higher heating value.

    Science.gov (United States)

    Mundike, Jhonnah; Collard, François-Xavier; Görgens, Johann F

    2016-06-01

    With the aim of controlling their proliferation, two invasive alien plants, Lantana camara (LC) and Mimosa pigra (MP), both widespread in Africa, were considered for torrefaction for renewable energy applications. Using thermogravimetric analysis, the influence of heating rate (HR: 2.18-19.82°Cmin(-1)) together with variable temperature and hold time on char yield and HHV (in a bomb calorimeter) were determined. Statistically significant effects of HR on HHV with optima at 10.5°Cmin(-1) for LC and 20°Cmin(-1) for MP were obtained. Increases of HHV up to 0.8MJkg(-1) or energy yield greater than 10%, together with a 3-fold reduction in torrefaction conversion time could be achieved by optimisation of HR. Analysis of the torrefaction volatiles by TG-MS showed that not only hemicelluloses, but also lignin conversion, could influence the optimum HR value.

  5. Influence of microwave heating on liquid-liquid phase inversion and temperature rates for immiscible mixtures.

    Science.gov (United States)

    Kennedy, Alvin; Tadesse, Solomon; Nunes, Janine; Reznik, Aron

    2011-01-01

    Time dependencies of component temperatures for mixtures of immiscible liquids during microwave heating were studied for acetonitrile-cyclohexane and water-toluene. For the first time, we report microwave induced liquid-liquid phase inversion for acetonitrile-cyclohexane mixture: acetonitrile layer was initially at the bottom of the mixture, after 10 sec of microwave heating its density decreased and it inverted to the top of the mixture for the remainder of the microwave heating. This phase inversion could not be achieved by conventional radiant heating. The maximum rate of temperature growth for the polar component of the mixtures was 2 - 5 times larger than for the non-polar component. This suggests that microwave energy is absorbed by polar liquids (water or acetonitrile) and heat is transferred into the non-polar liquid (toluene or cyclohexane) in the mixture by conduction (in case of cyclohexane) or conduction and convection (in case of toluene). Comparison between experimental data and semi-empirical mathematical models, proposed in [Kennedy et at., 2009] showed good correlation. Average relative error between theoretical and experimental results did not exceed 7%. These results can be used to model the temperature kinetics of components for other multiphase mixtures.

  6. A Surface Heat Disturbance Method for Measuring Local TIssue Blood Perfusion Rate

    Institute of Scientific and Technical Information of China (English)

    PengJianshu; TianYongquan

    1996-01-01

    A non-damage method for measuring local tissue blood perfusion rate by surface heat disturbance and its two special embodiments for realizing this measurement are presented in this paper,In the derivation of mathematical model,the Pennes equation is used,and two parameters which are very diffcult to be known-the arterial blood temperature Ta and the metabolic heat generation rate qm,have been eliminated.So if has provided a feasible basis for application.In this paper,the performance and the adaptable condition of the measurement method and its structure peculiarities are discussed over a wide variety of parameters.Moreover,the effectiveness of the measurement method has been demonstrated by means of the quantitative measurement of tissue in vitro,the comparative measurement of animal under artificial perfusion and the dependence measurement in human body.

  7. Heating rate and spin flip lifetime due to near field noise in layered superconducting atom chips

    CERN Document Server

    Fermani, Rachele; Zhang, Bo; Lim, Michael J; Dumke, Rainer

    2009-01-01

    We theoretically investigate the heating rate and spin flip lifetimes due to near field noise for atoms trapped close to layered superconducting structures. In particular, we compare the case of a gold layer deposited above a superconductor with the case of a bare superconductor. We study a niobium-based and a YBCO-based chip. For both niobium and YBCO chips at a temperature of 4.2 K, we find that the deposition of the gold layer can have a significant impact on the heating rate and spin flip lifetime, as a result of the increase of the near field noise. At a chip temperature of 77 K, this effect is less pronounced for the YBCO chip.

  8. Fissure formation in coke. 2: Effect of heating rate, shrinkage and coke strength

    Energy Technology Data Exchange (ETDEWEB)

    D.R. Jenkins; M.R. Mahoney [CSIRO, North Ryde, NSW (Australia). Mathematical and Information Sciences

    2010-07-15

    We investigate the effects of the heating rate, coke shrinkage and coke breakage strength upon the fissure pattern developed in a coke oven charge during carbonisation. This is done principally using a mechanistic model of the formation of fissures, which considers them to be an array of equally spaced fissures, whose depth follows a 'period doubling' pattern based upon the time history of the fissures. The model results are compared with pilot scale coke oven experiments. The results show that the effect of heating rate on the fissure pattern is different to the effect of coke shrinkage, while the effect of coke breakage strength on the pattern is less pronounced. The results can be seen in both the shape and size of resulting coke lumps after stabilisation. The approach gives the opportunity to consider means of controlling the carbonisation process in order to tune the size of the coke lumps produced. 7 refs., 18 figs., 4 tabs.

  9. Heat and mass transfer analogies for evaporation models at high evaporation rate

    OpenAIRE

    Trontin, P.; Villedieu, P.

    2014-01-01

    International audience; In the framework of anti and deicing applications, heated liquid films can appear above the ice thickness, or directly above the wall. Then, evaporation plays a major role in the Messinger balance and evaporated mass has to be predicted accurately. Unfortunately, it appears that existing models under-estimate evaporation at high temperature. In this study, different evaporation models at high evaporation rates are studied. The different hypothesis on which these models...

  10. Additive Effects of Heating and Exercise on Baroreflex Control of Heart Rate in Healthy Males.

    Science.gov (United States)

    Peçanha, Tiago; Forjaz, Claudia Lucia de Moraes; Low, David Andrew

    2017-08-31

    This study assessed the additive effects of passive heating and exercise on cardiac baroreflex sensitivity (cBRS) and heart rate variability (HRV). Twelve healthy young men (25±1 yrs, 23.8±0.5 kg/m(2)) randomly underwent two experimental sessions: heat stress (HS; whole-body heat stress using a tube-lined suit to increase core temperature by ~1°C) and normothermia (NT). Each session was composed of a: pre-intervention rest (REST1); HS or NT interventions; post-intervention rest (REST2); and 14 min of cycling exercise [7 min at 40%HRreserve (EX1) and 7 min at 60%HRreserve (EX2)]. Heart rate and finger blood pressure were continuously recorded. cBRS was assessed using the sequence (cBRSSEQ) and transfer function (cBRSTF) methods. HRV was assessed using the indices SDNN (standard deviation of RR intervals) and RMSSD (root mean square of successive RR intervals). cBRS and HRV were not different between sessions during EX1 and EX2 (i.e. matched heart rate conditions: EX1=116±3 vs. 114±3, EX2=143±4 vs. 142±3 bpm; but different workloads: EX1=50±9 vs. 114±8, EX2=106±10 vs. 165±8 Watts; for HS and NT, respectively; Pheart rates), cBRS and HRV were significantly reduced in HS (cBRSSEQ = 1.6±0.3 vs. 0.6±0.1 ms/mmHg, Pexercise does not affect cBRS and HRV. Alternatively, in workload-matched conditions, the addition of heat to exercise results in reduced cBRS and HRV compared to exercise in normothermia. Copyright © 2017, Journal of Applied Physiology.

  11. Volumetric Combustion Diagnostics

    Science.gov (United States)

    2017-01-03

    example involved a measurement campaign in collaboration with researchers at the Air Force Research Laboratory (Drs. Timothy Ombrello and Campbell ...its impact and promote AFOSR’s vision and mission. In this project, the PI has collaborated with Drs. Campbell Carter and Tim Ombrello to perform...Thermal-Fluid Systems, Heat Transfer Engineering, 37(3-4), 359-368, (2016) [9] Y.W. Lin Ma, Qingchun Lei, Wenjiang Xu, Campbell D. Carter, 3D Flame

  12. Template-assisted low temperature synthesis of functionalized graphene for ultrahigh volumetric performance supercapacitors.

    Science.gov (United States)

    Yan, Jun; Wang, Qian; Wei, Tong; Jiang, Lili; Zhang, Milin; Jing, Xiaoyan; Fan, Zhuangjun

    2014-05-27

    We demonstrated the fabrication of functionalized graphene nanosheets via low temperature (300 °C) treatment of graphite oxide with a slow heating rate using Mg(OH)2 nanosheets as template. Because of its dented sheet with high surface area, a certain amount of oxygen-containing groups, and low pore volume, the as-obtained graphene delivers both ultrahigh specific gravimetric and volumetric capacitances of 456 F g(-1) and 470 F cm(-3), almost 3.7 times and 3.3 times higher than hydrazine reduced graphene, respectively. Especially, the obtained volumetric capacitance is the highest value so far reported for carbon materials in aqueous electrolytes. More importantly, the assembled supercapacitor exhibits an ultrahigh volumetric energy density of 27.2 Wh L(-1), which is among the highest values for carbon materials in aqueous electrolytes, as well as excellent cycling stability with 134% of its initial capacitance after 10,000 cycles. Therefore, the present work holds a great promise for future design and large-scale production of high performance graphene electrodes for portable energy storage devices.

  13. Influence of Heating Rate on Double Reversible Transformation in CuZnAlMnNi Shape Memory Alloy

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The influence of heating rate on double reversible transformation in CuZnA1MnNi shape memory alloy was investigated by differential scanning calorimetry. It was found that rapid heating inhibits X→M transformation but is fa vorable to the reverse martensite transformation, giving rise to the approach of the two transformation peaks. With the decrease of heating rate, the two transformation peaks separate gradually.

  14. Influence of drying temperature, water content, and heating rate on gelatinization of corn starches.

    Science.gov (United States)

    Altay, Filiz; Gunasekaran, Sundaram

    2006-06-14

    The gelatinization properties of starch extracted from corn and waxy corn dried at different temperatures were determined at various water contents and heating rates by differential scanning calorimetry. All gelatinization transition temperatures increased with drying temperature and heating rate. Onset and peak temperatures remained relatively constant, whereas end temperature decreased in the presence of excess water. The gelatinization enthalpy (deltaH(g)) of corn starch decreased with drying temperature at 50% water; however, it remained constant for waxy corn starch. The effects of water content and heating rate on deltaH(g) were dependent on each other. The minimum water levels required for gelatinization of starch extracted from corn dried at 20 and 100 degrees C are 21 and 29%, respectively. The activation energy (E(a)) was calculated using an Arrhenius-type equation and two first-order models; the degree of conversion (alpha) was predicted using a newly proposed model that produced good results for both E(a) and alpha.

  15. The influence of the magnetic field on the heat transfer rate in rotating spherical shells

    Science.gov (United States)

    Cabello, Ares; Avila, Ruben

    2016-11-01

    Studies of the relationship between natural convection and magnetic field generation in spherical annular geometries with rotation are essential to understand the internal dynamics of the terrestrial planets. In such studies it is important to calculate and analyze the heat transfer rate at the inner and the outer spheres that confine the spherical gap. Previous investigations indicate that the magnetic field has a stabilizing effect on the onset of the natural convection, reduces the intensity of convection and modifies the flow patterns. However so far it is still unclear how the magnetic field change the heat transfer rate behaviour. We investigate the heat transfer rate (Nu) in a rotating spherical gap with a self gravity field varying linearly with radius, and its relation with the intensity of the magnetic field induced by the geodynamo effect. The Boussinesq fluid equations are solved by using a spectral element method (SEM). To avoid the singularity at the poles, the cubed-sphere algorithm is used to generate the spherical mesh. Several cases are simulated in which the Rayleigh number, the magnetic Reynolds number and the Taylor number are the variable parameters. The flow patterns, the temperature distribution and the Nusselt numbers at both spheres are calculated. Special thanks to DGAPA-UNAM Project PAPIIT IN11731, sponsor of this investigation.

  16. Effect of heating and cooling rate on the kinetics of allotropic phase changes in uranium: A differential scanning calorimetry study

    Energy Technology Data Exchange (ETDEWEB)

    Rai, Arun Kumar [Physical Metallurgy Division, Indira Gandhi Centre for Atomic Research (IGCAR), Kalpakkam 603 102, Tamilnadu (India); Raju, S. [Physical Metallurgy Division, Indira Gandhi Centre for Atomic Research (IGCAR), Kalpakkam 603 102, Tamilnadu (India)], E-mail: sraju@igcar.gov.in; Jeyaganesh, B.; Mohandas, E. [Physical Metallurgy Division, Indira Gandhi Centre for Atomic Research (IGCAR), Kalpakkam 603 102, Tamilnadu (India); Sudha, R.; Ganesan, V. [Materials Chemistry Division, Indira Gandhi Centre for Atomic Research (IGCAR), Kalpakkam 603 102, Tamilnadu (India)

    2009-01-01

    The kinetic aspects of allotropic phase changes in uranium are studied as a function of heating/cooling rate in the range 10{sup 0}-10{sup 2} K min{sup -1} by isochronal differential scanning calorimetry. The transformation arrest temperatures revealed a remarkable degree of sensitivity to variations of heating and cooling rate, and this is especially more so for the transformation finish (T{sub f}) temperatures. The results obtained for the {alpha} {yields} {beta} and {beta} {yields} {gamma} transformations during heating confirm to the standard Kolmogorov-Johnson-Mehl-Avrami (KJMA) model for a nucleation and growth mediated process. The apparent activation energy Q{sub eff} for the overall transformation showed a mild increase with increasing heating rate. In fact, the heating rate normalised Arrhenius rate constant, k/{beta} reveals a smooth power law decay with increasing heating rate ({beta}). For the {alpha} {yields} {beta} phase change, the observed DSC peak profile for slower heating rates contained a distinct shoulder like feature, which however is absent in the corresponding profiles found for higher heating rates. The kinetics of {gamma} {yields} {beta} phase change on the other hand, is best described by the two-parameter Koistinen-Marburger empirical relation for the martensitic transformation.

  17. Conception rate of artificially inseminated Holstein cows affected by cloudy vaginal mucus, under intense heat conditions

    Directory of Open Access Journals (Sweden)

    Miguel Mellado

    2015-06-01

    Full Text Available The objective of this work was to obtain prevalence estimates of cloudy vaginal mucus in artificially inseminated Holstein cows raised under intense heat, in order to assess the effect of meteorological conditions on its occurrence during estrus and to determine its effect on conception rate. In a first study, an association was established between the occurrence of cloudy vaginal mucus during estrus and the conception rate of inseminated cows (18,620 services, raised under intense heat (mean annual temperature of 22°C, at highly technified farms, in the arid region of northern Mexico. In a second study, data from these large dairy operations were used to assess the effect of meteorological conditions throughout the year on the occurrence of cloudy vaginal mucus during artificial insemination (76,899 estruses. The overall rate of estruses with cloudy vaginal mucus was 21.4% (16,470/76,899; 95% confidence interval = 21.1-21.7%. The conception rate of cows with clean vaginal mucus was higher than that of cows with abnormal mucus (30.6 vs. 22%. Prevalence of estruses with cloudy vaginal mucus was strongly dependent on high ambient temperature and markedly higher in May and June. Acceptable conception rates in high milk-yielding Holstein cows can only be obtained with cows showing clear and translucid mucus at artificial insemination.

  18. Quantitative Techniques in Volumetric Analysis

    Science.gov (United States)

    Zimmerman, John; Jacobsen, Jerrold J.

    1996-12-01

    Quantitative Techniques in Volumetric Analysis is a visual library of techniques used in making volumetric measurements. This 40-minute VHS videotape is designed as a resource for introducing students to proper volumetric methods and procedures. The entire tape, or relevant segments of the tape, can also be used to review procedures used in subsequent experiments that rely on the traditional art of quantitative analysis laboratory practice. The techniques included are: Quantitative transfer of a solid with a weighing spoon Quantitative transfer of a solid with a finger held weighing bottle Quantitative transfer of a solid with a paper strap held bottle Quantitative transfer of a solid with a spatula Examples of common quantitative weighing errors Quantitative transfer of a solid from dish to beaker to volumetric flask Quantitative transfer of a solid from dish to volumetric flask Volumetric transfer pipet A complete acid-base titration Hand technique variations The conventional view of contemporary quantitative chemical measurement tends to focus on instrumental systems, computers, and robotics. In this view, the analyst is relegated to placing standards and samples on a tray. A robotic arm delivers a sample to the analysis center, while a computer controls the analysis conditions and records the results. In spite of this, it is rare to find an analysis process that does not rely on some aspect of more traditional quantitative analysis techniques, such as careful dilution to the mark of a volumetric flask. Figure 2. Transfer of a solid with a spatula. Clearly, errors in a classical step will affect the quality of the final analysis. Because of this, it is still important for students to master the key elements of the traditional art of quantitative chemical analysis laboratory practice. Some aspects of chemical analysis, like careful rinsing to insure quantitative transfer, are often an automated part of an instrumental process that must be understood by the

  19. In situ synchrotron IR study relating temperature and heating rate to surface functional group changes in biomass.

    Science.gov (United States)

    Kirtania, Kawnish; Tanner, Joanne; Kabir, Kazi Bayzid; Rajendran, Sharmen; Bhattacharya, Sankar

    2014-01-01

    Three types of woody biomass were investigated under pyrolysis condition to observe the change in the surface functional groups by Fourier transform infrared (FTIR) technique with increasing temperature under two different (5 and 150°C/min) heating rates. The experiments were carried out in situ in the infrared microscopy beamline (IRM) of the Australian Synchrotron. The capability of the beamline made it possible to focus on single particles to obtain low noise measurements without mixing with KBr. At lower heating rate, the surface functional groups were completely removed by 550°C. In case of higher heating rate, a delay was observed in losing the functional groups. Even at a high temperature, significant number of functional groups was retained after the higher heating rate experiments. This implies that at considerably high heating rates typical of industrial reactors, more functional groups will remain on the surface.

  20. Statistical properties of Joule heating rate, electric field and conductances at high latitudes

    Directory of Open Access Journals (Sweden)

    A. T. Aikio

    2009-07-01

    Full Text Available Statistical properties of Joule heating rate, electric field and conductances in the high latitude ionosphere are studied by a unique one-month measurement made by the EISCAT incoherent scatter radar in Tromsø (66.6 cgmlat from 6 March to 6 April 2006. The data are from the same season (close to vernal equinox and from similar sunspot conditions (about 1.5 years before the sunspot minimum providing an excellent set of data to study the MLT and Kp dependence of parameters with high temporal and spatial resolution.

    All the parameters show a clear MLT variation, which is different for low and high Kp conditions. Our results indicate that the response of morning sector conductances and conductance ratios to increased magnetic activity is stronger than that of the evening sector. The co-location of Pedersen conductance maximum and electric field maximum in the morning sector produces the largest Joule heating rates 03–05 MLT for Kp≥3. In the evening sector, a smaller maximum occurs at 18 MLT. Minimum Joule heating rates in the nightside are statistically observed at 23 MLT, which is the location of the electric Harang discontinuity.

    An important outcome of the paper are the fitted functions for the Joule heating rate as a function of electric field magnitude, separately for four MLT sectors and two activity levels (Kp<3 and Kp≥3. In addition to the squared electric field, the fit includes a linear term to study the possible anticorrelation or correlation between electric field and conductance. In the midday sector, positive correlation is found as well as in the morning sector for the high activity case. In the midnight and evening sectors, anticorrelation between electric field and conductance is obtained, i.e. high electric fields are associated with low conductances. This is expected to occur in the return current regions adjacent to

  1. Molecular dynamics study on the effect of boundary heating rate on the phase change characteristics of thin film liquid

    Science.gov (United States)

    Hasan, Mohammad Nasim; Morshed, A. K. M. Monjur; Rabbi, Kazi Fazle; Haque, Mominul

    2016-07-01

    In this study, theoretical investigation of thin film liquid phase change phenomena under different boundary heating rates has been conducted with the help of molecular dynamics simulation. To do this, the case of argon boiling over a platinum surface has been considered. The study has been conducted to get a better understanding of the nano-scale physics of evaporation/boiling for a three phase system with particular emphasis on the effect of boundary heating rate. The simulation domain consisted of liquid and vapor argon atoms placed over a platinum wall. Initially the whole system was brought to an equilibrium state at 90K with the help of equilibrium molecular dynamics and then the temperature of the bottom wall was increased to a higher temperature (250K/130K) over a finite heating period. Depending on the heating period, the boundary heating rate has been varied in the range of 1600×109 K/s to 8×109 K/s. The variations of argon region temperature, pressure, net evaporation number with respect to time under different boundary heating rates have been determined and discussed. The heat fluxes normal to platinum wall for different cases were also calculated and compared with theoretical upper limit of maximum possible heat transfer to elucidate the effect of boundary heating rate.

  2. Volumetric Pricing of Agricultural Water Supplies: A Case Study

    Science.gov (United States)

    Griffin, Ronald C.; Perry, Gregory M.

    1985-07-01

    Models of water consumption by rice producers are conceptualized and then estimated using cross-sectional time series data obtained from 16 Texas canal operators for the years 1977-1982. Two alternative econometric models demonstrate that both volumetric and flat rate water charges are strongly and inversely related to agricultural water consumption. Nonprice conservation incentives accompanying flat rates are hypothesized to explain the negative correlation of flat rate charges and water consumption. Application of these results suggests that water supply organizations in the sample population converting to volumetric pricing will generally reduce water consumption.

  3. Effect of Heating Rate on Electromechanical Properties ofPNN–PZT Solid Solution

    Directory of Open Access Journals (Sweden)

    Virendra Singh

    2007-01-01

    Full Text Available Lead nickel niobate–lead zirconate titanate (Pb(Ni1/3Nb2/30.5 –Pb(Zr0.15Ti0.35O3, (PNN-PZTsolid solution was synthesised by columbite  process. Samples sintered at various heating ratesfor 4 h holding and their effect on electromechanical properties have been studied. When heatingrate was 8 °C/min from room temperature to 900 °C and holding for 4 h at 1280 °C, highest relativepermittivity and piezoelectric charge constant were observed, whereas heating rate of 3.5° C/min and holding for 4 h at 1280 °C have shown inferior electromechanical properties and graincoarsening. The piezoelectric charge constant (d33 ~612 pC/N and dielectric constant (e~ 5950observed in fast heating rate specimen as against to d33~ 137 pC/N and e~4294. XRD result showsthe formation of pyrochlore-free perovskite phase. Fine grains were observed  for fast heatingrate specimens.

  4. Test Facility for Volumetric Absorber

    Energy Technology Data Exchange (ETDEWEB)

    Ebert, M.; Dibowski, G.; Pfander, M.; Sack, J. P.; Schwarzbozl, P.; Ulmer, S.

    2006-07-01

    Long-time testing of volumetric absorber modules is an inevitable measure to gain the experience and reliability required for the commercialization of the open volumetric receiver technology. While solar tower test facilities are necessary for performance measurements of complete volumetric receivers, the long-term stability of individual components can be tested in less expensive test setups. For the qualification of the aging effects of operating cycles on single elements of new absorber materials and designs, a test facility was developed and constructed in the framework of the KOSMOSOL project. In order to provide the concentrated solar radiation level, the absorber test facility is integrated into a parabolic dish system at the Plataforma Solar de Almeria (PSA) in Spain. Several new designs of ceramic absorbers were developed and tested during the last months. (Author)

  5. Extension of the master sintering curve for constant heating rate modeling

    Science.gov (United States)

    McCoy, Tammy Michelle

    The purpose of this work is to extend the functionality of the Master Sintering Curve (MSC) such that it can be used as a practical tool for predicting sintering schemes that combine both a constant heating rate and an isothermal hold. Rather than just being able to predict a final density for the object of interest, the extension to the MSC will actually be able to model a sintering run from start to finish. Because the Johnson model does not incorporate this capability, the work presented is an extension of what has already been shown in literature to be a valuable resource in many sintering situations. A predicted sintering curve that incorporates a combination of constant heating rate and an isothermal hold is more indicative of what is found in real-life sintering operations. This research offers the possibility of predicting the sintering schedule for a material, thereby having advanced information about the extent of sintering, the time schedule for sintering, and the sintering temperature with a high degree of accuracy and repeatability. The research conducted in this thesis focuses on the development of a working model for predicting the sintering schedules of several stabilized zirconia powders having the compositions YSZ (HSY8), 10Sc1CeSZ, 10Sc1YSZ, and 11ScSZ1A. The compositions of the four powders are first verified using x-ray diffraction (XRD) and the particle size and surface area are verified using a particle size analyzer and BET analysis, respectively. The sintering studies were conducted on powder compacts using a double pushrod dilatometer. Density measurements are obtained both geometrically and using the Archimedes method. Each of the four powders is pressed into ¼" diameter pellets using a manual press with no additives, such as a binder or lubricant. Using a double push-rod dilatometer, shrinkage data for the pellets is obtained over several different heating rates. The shrinkage data is then converted to reflect the change in relative

  6. High-rate laser metal deposition of Inconel 718 component using low heat-input approach

    Science.gov (United States)

    Kong, C. Y.; Scudamore, R. J.; Allen, J.

    Currently many aircraft and aero engine components are machined from billets or oversize forgings. This involves significant cost, material wastage, lead-times and environmental impacts. Methods to add complex features to another component or net-shape surface would offer a substantial cost benefit. Laser Metal Deposition (LMD), currently being applied to the repair of worn or damaged aero engine components, was attempted in this work as an alternative process route, to build features onto a base component, because of its low heat input capability. In this work, low heat input and high-rate deposition was developed to deposit Inconel 718 powder onto thin plates. Using the optimised process parameters, a number of demonstrator components were successfully fabricated.

  7. Stage-specific heat effects: timing and duration of heat waves alter demographic rates of a global insect pest.

    Science.gov (United States)

    Zhang, Wei; Rudolf, Volker H W; Ma, Chun-Sen

    2015-12-01

    The frequency and duration of periods with high temperatures are expected to increase under global warming. Thus, even short-lived organisms are increasingly likely to experience periods of hot temperatures at some point of their life-cycle. Despite recent progress, it remains unclear how various temperature experiences during the life-cycle of organisms affect demographic traits. We simulated hot days (daily mean temperature of 30 °C) increasingly experienced under field conditions and investigated how the timing and duration of such hot days during the life cycle of Plutella xylostella affects adult traits. We show that hot days experienced during some life stages (but not all) altered adult lifespan, fecundity, and oviposition patterns. Importantly, the effects of hot days were contingent on which stage was affected, and these stage-specific effects were not always additive. Thus, adults that experience different temporal patterns of hot periods (i.e., changes in timing and duration) during their life-cycle often had different demographic rates and reproductive patterns. These results indicate that we cannot predict the effects of current and future climate on natural populations by simply focusing on changes in the mean temperature. Instead, we need to incorporate the temporal patterns of heat events relative to the life-cycle of organisms to describe population dynamics and how they will respond to future climate change.

  8. Design and simulation of heat exchangers using Aspen HYSYS, and Aspen exchanger design and rating for paddy drying application

    Science.gov (United States)

    Janaun, J.; Kamin, N. H.; Wong, K. H.; Tham, H. J.; Kong, V. V.; Farajpourlar, M.

    2016-06-01

    Air heating unit is one of the most important parts in paddy drying to ensure the efficiency of a drying process. In addition, an optimized air heating unit does not only promise a good paddy quality, but also save more for the operating cost. This study determined the suitable and best specifications heating unit to heat air for paddy drying in the LAMB dryer. In this study, Aspen HYSYS v7.3 was used to obtain the minimum flow rate of hot water needed. The resulting data obtained from Aspen HYSYS v7.3 were used in Aspen Exchanger Design and Rating (EDR) to generate heat exchanger design and costs. The designs include shell and tubes and plate heat exchanger. The heat exchanger was designed in order to produce various drying temperatures of 40, 50, 60 and 70°C of air with different flow rate, 300, 2500 and 5000 LPM. The optimum condition for the heat exchanger were found to be plate heat exchanger with 0.6 mm plate thickness, 198.75 mm plate width, 554.8 mm plate length and 11 numbers of plates operating at 5000 LPM air flow rate.

  9. The influence of heating rate on superconducting characteristics of MgB{sub 2} obtained by spark plasma sintering technique

    Energy Technology Data Exchange (ETDEWEB)

    Aldica, G. [National Institute of Materials Physics, Atomistilor 105bis, 077125 Magurele (Romania); Burdusel, M. [National Institute of Materials Physics, Atomistilor 105bis, 077125 Magurele (Romania); Faculty of Materials Science and Engineering, University ’Politehnica’ of Bucharest, Splaiul Independentei 313, 060042 Bucharest (Romania); Popa, S.; Enculescu, M.; Pasuk, I. [National Institute of Materials Physics, Atomistilor 105bis, 077125 Magurele (Romania); Badica, P., E-mail: badica2003@yahoo.com [National Institute of Materials Physics, Atomistilor 105bis, 077125 Magurele (Romania)

    2015-12-15

    Highlights: • MgB{sub 2} was obtained by ex-situ spark plasma sintering for different heating rates. • Heating rates were 20–475 °C/min: the optimum heating rate is ∼100 °C/min. • For 100 °C/min, J{sub c0}, H{sub irr} and (J{sub c0} x μ{sub 0}H{sub irr}) have maximum values. • For 100 °C/min, macro flux jumps are partially suppressed at 5 K. • Grain boundaries are modified depending on the heating rate. - Abstract: Superconducting bulks of MgB{sub 2} were obtained by the Spark Plasma Sintering (SPS) technique. Different heating rates of 20, 100, 235, 355, and 475 °C/min were used. Samples have high density, above 95%. The onset critical temperature T{sub c}, is about 38.8 K. There is an optimum heating rate of ∼100 °C/min to maximize the critical current density J{sub c0}, the irreversibility field H{sub irr}, the product (J{sub c0} x μ{sub 0}H{sub irr}), and to partially avoid formation of undesirable flux jumps at low temperatures. Significant microstructure differences were revealed for samples processed with low and high heating rates in respect to grain boundaries.

  10. Calculations of Solar Shortwave Heating Rates due to Black Carbon and Ozone Absorption Using in Situ Measurements

    Science.gov (United States)

    Gao, R. S.; Hall, S. R.; Swartz, W. H.; Spackman, J. R.; Watts, L. A.; Fahey, D. W.; Aikin, K. C.; Shetter, R. E.; Bui, T. P.

    2008-01-01

    Results for the solar heating rates in ambient air due to absorption by black-carbon (BC) containing particles and ozone are presented as calculated from airborne observations made in the tropical tropopause layer (TTL) in January-February 2006. The method uses airborne in situ observations of BC particles, ozone and actinic flux. Total BC mass is obtained along the flight track by summing the masses of individually detected BC particles in the range 90 to 600-nm volume-equivalent diameter, which includes most of the BC mass. Ozone mixing ratios and upwelling and partial downwelling solar actinic fluxes were measured concurrently with BC mass. Two estimates used for the BC wavelength-dependent absorption cross section yielded similar heating rates. For mean altitudes of 16.5, 17.5, and 18.5 km (0.5 km) in the tropics, average BC heating rates were near 0.0002 K/d. Observed BC coatings on individual particles approximately double derived BC heating rates. Ozone heating rates exceeded BC heating rates by approximately a factor of 100 on average and at least a factor of 4, suggesting that BC heating rates in this region are negligible in comparison.

  11. Magnetic volumetric hologram memory with magnetic garnet.

    Science.gov (United States)

    Nakamura, Yuichi; Takagi, Hiroyuki; Lim, Pang Boey; Inoue, Mitsuteru

    2014-06-30

    Holographic memory is a promising next-generation optical memory that has a higher recording density and a higher transfer rate than other types of memory. In holographic memory, magnetic garnet films can serve as rewritable holographic memory media by use of magneto-optical effect. We have now demonstrated that a magnetic hologram can be recorded volumetrically in a ferromagnetic garnet film and that the signal image can be reconstructed from it for the first time. In addition, multiplicity of the magnetic hologram was also confirmed; the image could be reconstructed from a spot overlapped by other spots.

  12. Numerical Studies on Heat Release Rate in Room Fire on Liquid Fuel under Different Ventilation Factors

    Directory of Open Access Journals (Sweden)

    N. Cai

    2012-01-01

    Full Text Available Heat release rate (HRR of the design fire is the most important parameter in assessing building fire hazards. However, HRR in room fire was only studied by computational fluid dynamics (CFD in most of the projects determining fire safety provisions by performance-based design. In contrast to ten years ago, officers in the Far East are now having better knowledge of CFD. Two common questions are raised on CFD-predicted results on describing free boundaries; and on computing grid size. In this work, predicting HRR by the CFD model was justified with experimental room pool fire data reported earlier. The software fire dynamics simulator (FDS version 5 was selected as the CFD simulation tool. Prescribed input heating rate based on the experimental results was used with the liquid fuel model in FDS. Five different free boundary conditions were investigated to predict HRR. Grid sensitivity study was carried out using one stretched mesh and multiple uniform meshes with different grid sizes. As it is difficult to have the entire set of CFD predicted results agreed with experiments, macroscopic flow parameters on the mass flow rate through door opening predicted by CFD were also justified by another four conditions with different ventilation factors.

  13. Specific heat flow rate: an on-line monitor and potential control variable of specific metabolic rate in animal cell culture that combines microcalorimetry with dielectric spectroscopy.

    Science.gov (United States)

    Guan, Y; Evans, P M; Kemp, R B

    1998-06-05

    One of the requirements for enhanced productivity by the animal culture systems used in biotechnology is the direct assessment of the metabolic rate by on-line biosensors. Based on the fact that cell growth is associated with an enthalpy change, it is shown that the specific heat flow rate is stoichiometrically related to the net specific rates of substrates, products, and indeed to specific growth rate, and therefore a direct reflection of metabolic rate. Heat flow rate measured by conduction calorimetry has a technical advantage over estimates for many material flows which require assays at a minimum of two discrete times to give the rate. In order to make heat flow rate specific to the amount of the living cellular system, it would be advantageous to divide it by viable biomass. This requirement has been fulfilled by combining a continuous flow microcalorimeter ex situ with a dielectric spectroscope in situ, the latter measuring the viable cell mass volume fraction. The quality of the resulting biosensor for specific heat flow rate was illustrated using batch cultures of Chinese hamster ovary cells (CHO 320) producing recombinant human interferon-gamma (IFN-gamma) during growth in a stirred tank bioreactor under fully aerobic conditions. The measuring scatter of the probe was decreased significantly by applying the moving average technique to the two participant signals. It was demonstrated that the total metabolic rate of the cells, as indicated by the specific heat flow rate sensor, decreased with increasing time in batch culture, coincident with the decline in the two major substrates, glucose and glutamine, and the accumulation of the by-products, ammonia and lactate. Furthermore, the specific heat flow rate was an earlier indicator of substrate depletion than the flow rate alone. The calorimetric-respirometric ratio showed the intensive participation of anaerobic processes during growth and the related IFN-gamma production. Specific heat flow rate was

  14. Thermal Analysis On The Kinetics Of Magnesium-Aluminum Layered Double Hydroxides In Different Heating Rates

    Directory of Open Access Journals (Sweden)

    Hongbo Y.

    2015-06-01

    Full Text Available The thermal decomposition of magnesium-aluminum layered double hydroxides (LDHs was investigated by thermogravimetry analysis and differential scanning calorimetry (DSC methods in argon environment. The influence of heating rates (including 2.5, 5, 10, 15 and 20K/min on the thermal behavior of LDHs was revealed. By the methods of Kissinger and Flynn-Wall-Ozawa, the thermal kinetic parameters of activation energy and pre-exponential factor for the exothermic processes under non-isothermal conditions were calculated using the analysis of corresponding DSC curves.

  15. Effect of heating rate on toxicity of pyrolysis gases from some elastomers

    Science.gov (United States)

    Hilado, C. J.; Kosola, K. L.; Solis, A. N.

    1977-01-01

    The effect of heating rate on the toxicity of the pyrolysis gases from six elastomers was investigated, using a screening test method. The elastomers were polyisoprene (natural rubber), styrene-butadiene rubber (SBR), ethylene propylene diene terpolymer (EPDM), acrylonitrile rubber, chlorosulfonated polyethylene rubber, and polychloroprene. The rising temperature and fixed temperature programs produced exactly the same rank order of materials based on time to death. Acrylonitrile rubber exhibited the greatest toxicity under these test conditions, and carbon monoxide was not found in sufficient concentrations to be the primary cause of death.

  16. Simultaneous optimization of the cavity heat load and trip rates in linacs using a genetic algorithm

    Directory of Open Access Journals (Sweden)

    Balša Terzić

    2014-10-01

    Full Text Available In this paper, a genetic algorithm-based optimization is used to simultaneously minimize two competing objectives guiding the operation of the Jefferson Lab’s Continuous Electron Beam Accelerator Facility linacs: cavity heat load and radio frequency cavity trip rates. The results represent a significant improvement to the standard linac energy management tool and thereby could lead to a more efficient Continuous Electron Beam Accelerator Facility configuration. This study also serves as a proof of principle of how a genetic algorithm can be used for optimizing other linac-based machines.

  17. Effect of heating rate on toxicity of pyrolysis gases from some synthetic polymers

    Science.gov (United States)

    Hilado, C. J.; Soriano, J. A.; Kosola, K. L.

    1977-01-01

    The effect of heating rate on the toxicity of the pyrolysis gases from some synthetic polymers was investigate, using a screening test method. The synthetic polymers were polyethylene, polystyrene, polymethyl methacrylate, polycarbonate, ABS, polyaryl sulfone, polyether sulfone, and polyphenylene sulfide. The toxicants from the sulfur-containing polymers appeared to act more rapidly than the toxicants from the other polymers. It is not known whether this effect is due primarily to differences in concentration or in the nature of the toxicants. The carbon monoxide concentrations found do not account for the observed results.

  18. The influence of heating rate on superconducting characteristics of MgB2 obtained by spark plasma sintering technique

    Science.gov (United States)

    Aldica, G.; Burdusel, M.; Popa, S.; Enculescu, M.; Pasuk, I.; Badica, P.

    2015-12-01

    Superconducting bulks of MgB2 were obtained by the Spark Plasma Sintering (SPS) technique. Different heating rates of 20, 100, 235, 355, and 475 °C/min were used. Samples have high density, above 95%. The onset critical temperature Tc, is about 38.8 K. There is an optimum heating rate of ∼100 °C/min to maximize the critical current density Jc0, the irreversibility field Hirr, the product (Jc0 x μ0Hirr), and to partially avoid formation of undesirable flux jumps at low temperatures. Significant microstructure differences were revealed for samples processed with low and high heating rates in respect to grain boundaries.

  19. Thermal conductance and basal metabolic rate are part of a coordinated system for heat transfer regulation.

    Science.gov (United States)

    Naya, Daniel E; Spangenberg, Lucía; Naya, Hugo; Bozinovic, Francisco

    2013-09-22

    Thermal conductance measures the ease with which heat leaves or enters an organism's body. Although the analysis of this physiological variable in relation to climatic and ecological factors can be traced to studies by Scholander and colleagues, only small advances have occurred ever since. Here, we analyse the relationship between minimal thermal conductance estimated during summer (Cmin) and several ecological, climatic and geographical factors for 127 rodent species, in order to identify the exogenous factors that have potentially affected the evolution of thermal conductance. In addition, we evaluate whether there is compensation between Cmin and basal metabolic rate (BMR)-in such a way that a scale-invariant ratio between both variables is equal to one-as could be expected from the Scholander-Irving model of heat transfer. Our major findings are (i) annual mean temperature is the best single predictor of mass-independent Cmin. (ii) After controlling for the effect of body mass, there is a strong positive correlation between log10 (Cmin) and log10 (BMR). Further, the slope of this correlation is close to one, indicating an almost perfect compensation between both physiological variables. (iii) Structural equation modelling indicated that Cmin values are adjusted to BMR values and not the other way around. Thus, our results strongly suggest that BMR and thermal conductance integrate a coordinated system for heat regulation in endothermic animals and that summer conductance values are adjusted (in an evolutionary sense) to track changes in BMRs.

  20. Volumetric polymerization shrinkage of contemporary composite resins

    Directory of Open Access Journals (Sweden)

    Halim Nagem Filho

    2007-10-01

    Full Text Available The polymerization shrinkage of composite resins may affect negatively the clinical outcome of the restoration. Extensive research has been carried out to develop new formulations of composite resins in order to provide good handling characteristics and some dimensional stability during polymerization. The purpose of this study was to analyze, in vitro, the magnitude of the volumetric polymerization shrinkage of 7 contemporary composite resins (Definite, Suprafill, SureFil, Filtek Z250, Fill Magic, Alert, and Solitaire to determine whether there are differences among these materials. The tests were conducted with precision of 0.1 mg. The volumetric shrinkage was measured by hydrostatic weighing before and after polymerization and calculated by known mathematical equations. One-way ANOVA (a or = 0.05 was used to determine statistically significant differences in volumetric shrinkage among the tested composite resins. Suprafill (1.87±0.01 and Definite (1.89±0.01 shrank significantly less than the other composite resins. SureFil (2.01±0.06, Filtek Z250 (1.99±0.03, and Fill Magic (2.02±0.02 presented intermediate levels of polymerization shrinkage. Alert and Solitaire presented the highest degree of polymerization shrinkage. Knowing the polymerization shrinkage rates of the commercially available composite resins, the dentist would be able to choose between using composite resins with lower polymerization shrinkage rates or adopting technical or operational procedures to minimize the adverse effects deriving from resin contraction during light-activation.

  1. Instantaneous Metabolic Cost of Walking: Joint-Space Dynamic Model with Subject-Specific Heat Rate

    Science.gov (United States)

    Roberts, Dustyn; Hillstrom, Howard; Kim, Joo H.

    2016-01-01

    A subject-specific model of instantaneous cost of transport (ICOT) is introduced from the joint-space formulation of metabolic energy expenditure using the laws of thermodynamics and the principles of multibody system dynamics. Work and heat are formulated in generalized coordinates as functions of joint kinematic and dynamic variables. Generalized heat rates mapped from muscle energetics are estimated from experimental walking metabolic data for the whole body, including upper-body and bilateral data synchronization. Identified subject-specific energetic parameters—mass, height, (estimated) maximum oxygen uptake, and (estimated) maximum joint torques—are incorporated into the heat rate, as opposed to the traditional in vitro and subject-invariant muscle parameters. The total model metabolic energy expenditure values are within 5.7 ± 4.6% error of the measured values with strong (R2 > 0.90) inter- and intra-subject correlations. The model reliably predicts the characteristic convexity and magnitudes (0.326–0.348) of the experimental total COT (0.311–0.358) across different subjects and speeds. The ICOT as a function of time provides insights into gait energetic causes and effects (e.g., normalized comparison and sensitivity with respect to walking speed) and phase-specific COT, which are unavailable from conventional metabolic measurements or muscle models. Using the joint-space variables from commonly measured or simulated data, the models enable real-time and phase-specific evaluations of transient or non-periodic general tasks that use a range of (aerobic) energy pathway similar to that of steady-state walking. PMID:28030598

  2. A simple parameterization of ozone infrared absorption for atmospheric heating rate calculations

    Science.gov (United States)

    Rosenfield, Joan E.

    1991-01-01

    A simple parameterization of ozone absorption in the 9.6-micron region which is suitable for two- and three-dimensional stratospheric and tropospheric models is presented. The band is divided into two parts, a brand center region and a band wing region, grouping together regions for which the temperature dependence of absorption is similar. Each of the two regions is modeled with a function having the form of the Goody random model, with pressure and temperature dependent band parameters chosen by empirically fitting line-by-line equivalent widths for pressures between 0.25 and 1000 mbar and ozone absorber amounts between 1.0 x 10 to the -7th and 1.0 cm atm. The model has been applied to calculations of atmospheric heating rates using an absorber amount weighted mean pressure and temperature along the inhomogeneous paths necessary for flux computations. In the stratosphere, maximum errors in the heating rates relative to line-by-line calculations are 0.1 K/d, or 5 percent of the peak cooling at the stratopause. In the troposphere the errors are at most 0.005 K/d.

  3. Effect of heating rate on temperature of titanium alloy (. cap alpha. +. beta. ). -->. beta. transformaton

    Energy Technology Data Exchange (ETDEWEB)

    Gridnev, V.N.; Ivasishin, O.M.; Markovskij, P.E. (AN Ukrainskoj SSR, Kiev. Inst. Metallofiziki)

    1985-01-01

    The effect of doping of two-phase titaniums alloys and morphology of initial structure on the Tsub(t) temperature shift value of (..cap alpha..+..beta..)..--> beta.. transformation depending on heating rate is investigated. It has been found that the Tsub(t) shift occurs in the strictly determined temperature range depending on chemical alloy composition. The Tsub(t) shift is directly proportional to the Ksub(..beta..) coefficient applied as a quantitative alloying characteristic as well as a dimensional factor equal either to the plate thickness or the ..cap alpha..-phase globule diameter depending on the type of initial structure. In the limits of this temperature range the (..cap alpha..+..beta..)..--> beta..-transformation occurs completely according to the diffusion mechanism. The critical heating rate at which maximum permissible Tsub(t) value is attained and above which its stabilization is observed is determined by the same parameters - the alloy doping degree characterized by the Ksub(..beta..) coefficient and the ..cap alpha..-phase crystal dimensions in the initial structure.

  4. Mathematical model of cycad cones' thermogenic temperature responses: inverse calorimetry to estimate metabolic heating rates.

    Science.gov (United States)

    Roemer, R B; Booth, D; Bhavsar, A A; Walter, G H; Terry, L I

    2012-12-21

    A mathematical model based on conservation of energy has been developed and used to simulate the temperature responses of cones of the Australian cycads Macrozamia lucida and Macrozamia. macleayi during their daily thermogenic cycle. These cones generate diel midday thermogenic temperature increases as large as 12 °C above ambient during their approximately two week pollination period. The cone temperature response model is shown to accurately predict the cones' temperatures over multiple days as based on simulations of experimental results from 28 thermogenic events from 3 different cones, each simulated for either 9 or 10 sequential days. The verified model is then used as the foundation of a new, parameter estimation based technique (termed inverse calorimetry) that estimates the cones' daily metabolic heating rates from temperature measurements alone. The inverse calorimetry technique's predictions of the major features of the cones' thermogenic metabolism compare favorably with the estimates from conventional respirometry (indirect calorimetry). Because the new technique uses only temperature measurements, and does not require measurements of oxygen consumption, it provides a simple, inexpensive and portable complement to conventional respirometry for estimating metabolic heating rates. It thus provides an additional tool to facilitate field and laboratory investigations of the bio-physics of thermogenic plants. Copyright © 2012 Elsevier Ltd. All rights reserved.

  5. Heat rate improvement at Sunflower Electric`s Holcomb Station - a programmatic approach

    Energy Technology Data Exchange (ETDEWEB)

    Linville, C.; Nelson, K.E.; DesJardins, R.R.

    1996-05-01

    This paper describes the heat rate improvement program implemented at Sunflower Electric Power Corporations Holcomb Generating Station located in Holcomb, Kansas. The Holcomb Station is a large coal-fired generating plant that supplies electricity to Southwestern. Kansas and surrounding states. In 1993, Sunflower Electric (SEPC) established a continuing heat rate improvement program at the Holcomb Station which consisted of a periodic performance test program in combination with continuous on-line monitoring. This paper provides an overview of the test program and initial results and describes a unique approach to monitoring boiler feed pump performance especially suitable for on-line monitoring. implementation of a 15-user LAN-based on-line performance monitoring system is also described. In addition to technical issues, the paper addresses some of the {open_quotes}human factors{close_quotes} encountered while promoting acceptance and use of the on-line monitoring system by all levels of plant personnel. The importance of proper program planning and long term management support is stressed.

  6. Experimental investigation on heat transfer rate of Co–Mn ferrofluids in external magnetic field

    Directory of Open Access Journals (Sweden)

    Margabandhu M.

    2016-06-01

    Full Text Available Manganese substituted cobalt ferrite (Co1–xMnxFe2O4 with x = 0, 0.3, 0.5, 0.7 and 1 nanopowders were synthesized by chemical coprecipitation method. The synthesized magnetic nanoparticles were investigated by various characterization techniques, such as X-ray diffraction (XRD, vibrating sample magnetometry (VSM, scanning electron microscopy (SEM and thermogravimetric and differential thermal analysis (TG/DTA. The XRD results confirmed the presence of cubic spinel structure of the prepared powders and the average crystallite size of magnetic particles ranging from 23 to 45 nm. The VSM results showed that the magnetic properties varied with an increase in substituted manganese while SEM analysis showed the change in the morphology of obtained magnetic nanoparticles. The TG/DTA analysis indicated the formation of crystalline structure of the synthesized samples. The heat transfer rate was measured in specially prepared magnetic nanofluids (nanoparticles dispersed in carrier fluid transformer oil as a function of time and temperature in presence of external magnetic fields. The experimental analysis indicated enhanced heat transfer rate of the magnetic nanofluids which depended upon the strength of external magnetic field and chemical composition.

  7. Analysis of read-out heating rate effects on the glow peaks of TLD-100 using WinGCF software

    Energy Technology Data Exchange (ETDEWEB)

    Bauk, Sabar, E-mail: sabar@usm.my [Physics Section, School of Distance Education, Universiti Sains Malaysia, 11800 USM, Penang (Malaysia); Hussin, Siti Fatimah [School of Physics, Universiti Sains Malaysia, 11800 USM, Penang (Malaysia); Alam, Md. Shah [Physics Section, School of Distance Education, Universiti Sains Malaysia, 11800 USM, Penang (Malaysia); Physics Department, Shahjalal University of Science and Technology, Sylhet (Bangladesh)

    2016-01-22

    This study was done to analyze the effects of the read-out heating rate on the LiF:Mg,Ti (TLD-100) thermoluminescent dosimeters (TLD) glow peaks using WinGCF computer software. The TLDs were exposed to X-ray photons with a potential difference of 72 kVp and 200 mAs in air and were read-out using a Harshaw 3500 TLD reader. The TLDs were read-out using four read-out heating rates at 10, 7, 4 and 1 °C s{sup −1}. It was observed that lowering the heating rate could separate more glow peaks. The activation energy for peak 5 was found to be lower than that for peak 4. The peak maximum temperature and the integral value of the main peak decreased as the heating rate decreases.

  8. Investigations on the heat transport capability of a cryogenic oscillating heat pipe and its application in achieving ultra-fast cooling rates for cell vitrification cryopreservation.

    Science.gov (United States)

    Han, Xu; Ma, Hongbin; Jiao, Anjun; Critser, John K

    2008-06-01

    Theoretically, direct vitrification of cell suspensions with relatively low concentrations ( approximately 1 M) of permeating cryoprotective agents (CPA) is suitable for cryopreservation of almost all cell types and can be accomplished by ultra-fast cooling rates that are on the order of 10(6-7) K/min. However, the methods and devices currently available for cell cryopreservation cannot achieve such high cooling rates. In this study, we constructed a novel cryogenic oscillating heat pipe (COHP) using liquid nitrogen as its working fluid and investigated its heat transport capability to assess its application for achieving ultra-fast cooling rates for cell cryopreservation. The experimental results showed that the apparent heat transfer coefficient of the COHP can reach 2 x 10(5) W/m(2).K, which is two orders of the magnitude higher than traditional heat pipes. Theoretical analyzes showed that the average local heat transfer coefficient in the thin film evaporation region of the COHP can reach 1.2 x 10(6) W/m(2).K, which is approximately 10(3) times higher than that achievable with standard pool-boiling approaches. Based on these results, a novel device design applying the COHP and microfabrication techniques is proposed and its efficiency for cell vitrification is demonstrated through numerical simulation. The estimated average cooling rates achieved through this approach is 10(6-7)K/min, which is much faster than the currently available methods and sufficient for achieving vitrification with relatively low concentrations of CPA.

  9. The Dependence of Atmospheric Circulation and Heat Transport on the Planetary Rotation Rate

    Science.gov (United States)

    Basu, S.; Richardson, M. I.; Wilson, R. J.

    2002-12-01

    Simplified models of planetary climate require a parameterization for the equator-to-pole transport of heat and its dependence on factors, including the planetary rotation rate. Various such parameterizations exist, including ones based on the theory of baroclinic eddy mixing, and on principles of global entropy generation. However, such parameterizations are difficult to test given the limited available observational opportunities. In this study, we use a numerical model to examine heat flux dependencies, as part of a wider study of circulation regime sensitivity to rotation rates and other parameters. This study makes use of a simplified version of the Geophysical Fluid Dynamics Laboratory (GFDL) "Skyhi" General Circulation Model (GCM). All terrestrial hydrological processes have been stripped from the model, which in the form used here, is adapted from the Martian version of Skyhi. The atmosphere has the gas properties of CO2, except that it has been made uncondensible. No aerosols or surface ices are allowed. The model surface is flat, and of uniform albedo and thermal inertia. For the simulations presented in this study, the diurnal, seasonal, and eccentricity cycles have been disabled ({ i.e.} the surface and atmosphere receives constant, daily- and seasonally-averaged incident solar radiation). Radiative heating is treated with a band model for CO2 gas in the thermal and near-infrared bands. The use of a complex model to examine simplified theory of heat transport requires some justification since it is not necessarily clear that these models (GCM's) provide an accurate emulation of the real atmosphere (of any given planet). In this study, we have intentionally removed those aspects of GCM's that are of greatest concern. Especially for terrestrial GCM's, the hydrologic cycle is a major source of uncertainty due to radiative feedbacks, and cloud coupling to small-scale, convective mixing. For other planets, aerosols are important as radiatively and dynamical

  10. The effect of temperature and heating rate on char properties obtained from solar pyrolysis of beech wood.

    Science.gov (United States)

    Zeng, Kuo; Minh, Doan Pham; Gauthier, Daniel; Weiss-Hortala, Elsa; Nzihou, Ange; Flamant, Gilles

    2015-04-01

    Char samples were produced from pyrolysis in a lab-scale solar reactor. The pyrolysis of beech wood was carried out at temperatures ranging from 600 to 2000°C, with heating rates from 5 to 450°C/s. CHNS, scanning electron microscopy analysis, X-ray diffractometry, Brunauer-Emmett-Teller adsorption were employed to investigate the effect of temperature and heating rate on char composition and structure. The results indicated that char structure was more and more ordered with temperature increase and heating rate decrease (higher than 50°C/s). The surface area and pore volume firstly increased with temperature and reached maximum at 1200°C then reduced significantly at 2000°C. Besides, they firstly increased with heating rate and then decreased slightly at heating rate of 450°C/s when final temperature was no lower than 1200°C. Char reactivity measured by TGA analysis was found to correlate with the evolution of char surface area and pore volume with temperature and heating rate.

  11. Effect of Heating Rate on Accelerated Carbide Spheroidisation (ASR in 100CrMnSi6-4 Bearing Steel

    Directory of Open Access Journals (Sweden)

    Hauserova D.

    2014-10-01

    Full Text Available Typical processing routes for bearing steels include a soft annealing stage, the purpose of which is to obtain a microstructure containing globular carbides in ferritic matrix. A newly developed process called ASR cuts the carbide spheroidisation times several fold, producing considerably finer globular carbides than conventional soft annealing. The present paper explores the effect of the heating rate and temperature on the accelerated carbide spheroidisation process and on the resulting hardness. Accelerated spheroidisation was achieved by thermal cycling for several minutes around various temperatures close to the transformation temperature at various heating rates applied by induction heating.

  12. Investigating Cooling Rates of a Controlled Lava Flow using Infrared Imaging and Three Heat Diffusion Models

    Science.gov (United States)

    Tarlow, S.; Lev, E.; Zappa, C. J.; Karson, J.; Wysocki, B.

    2011-12-01

    Observation and investigation of surface cooling rates of active lava flows can help constrain thermal parameters necessary for creating of more precise lava flow models. To understand how the lava cools, temperature data was collected using an infrared video camera. We explored three models of the release of heat from lava stream; one based on heat conduction, another based on crust thickness and radiation, and a third model based on radiative cooling and variable crust thickness. The lava flow, part of the Syracuse University Lava Project (http://lavaproject.syr.edu), was made by pouring molten basalt at 1300 Celsius from a furnace into a narrow trench of sand. Hanging roughly 2 m over the trench, the infrared camera, records the lava's surface temperature for the duration of the flow. We determine the average surface temperature of the lava flow at a fixed location downstream as the mean of the lateral cross section of each frame of the IR imagery. From the recorded IR frames, we calculate the mean cross-channel temperature for each downstream distance. We then examine how this mean temperature evolves over time, and plot cooling curves for selected down-stream positions. We then compared the observed cooling behavior to that predicted by three cooling models: a conductive cooling model, a radiative cooling model with constant crust thickness, and a radiative cooling model with variable crust thickness. All three models are solutions to the one-dimensional heat equation. To create the best fit for the conductive model, we constrained thermal diffusivity and to create the best fit for the radiative model, we constrained crust thickness. From the comparison of our data to the models we can conclude that the lava flow's cooling is primarily driven by radiation.

  13. Gamma ray heating rates due to chromium isotopes in stellar core during late stages of high mass stars (>10M⊙

    Directory of Open Access Journals (Sweden)

    Nabi Jameel-Un

    2017-01-01

    Full Text Available Gamma ray heating rates are thought to play a crucial role during the pre-supernova stage of high mass stars. Gamma ray heating rates, due to β±-decay and electron (positron capture on chromium isotopes, are calculated using proton-neutron quasiparticle random phase approximation theory. The electron capture significantly affects the lepton fraction (Ye and accelerates the core contraction. The gamma rays emitted as a result of weak processes heat the core and tend to hinder the cooling and contraction due to electron capture and neutrino emission. The emitted gamma rays tend to produce enormous entropy and set the convection to play its role at this stage. The gamma heating rates, on 50-60Cr, are calculated for the density range 10 < ρ (g.cm-3 < 1011 and temperature range 107 < T (K < 3.0×1010.

  14. Integration and software for thermal test of heat rate sensors. [space shuttle external tank

    Science.gov (United States)

    Wojciechowski, C. J.; Shrider, K. R.

    1982-01-01

    A minicomputer controlled radiant test facility is described which was developed and calibrated in an effort to verify analytical thermal models of instrumentation islands installed aboard the space shuttle external tank to measure thermal flight parameters during ascent. Software was provided for the facility as well as for development tests on the SRB actuator tail stock. Additional testing was conducted with the test facility to determine the temperature and heat flux rate and loads required to effect a change of color in the ET tank external paint. This requirement resulted from the review of photographs taken of the ET at separation from the orbiter which showed that 75% of the external tank paint coating had not changed color from its original white color. The paint on the remaining 25% of the tank was either brown or black, indicating that it had degraded due to heating or that the spray on form insulation had receded in these areas. The operational capability of the facility as well as the various tests which were conducted and their results are discussed.

  15. Development of a water boil-off spent-fuel calorimeter system. [To measure decay heat generation rate

    Energy Technology Data Exchange (ETDEWEB)

    Creer, J.M.; Shupe, J.W. Jr.

    1981-05-01

    A calorimeter system was developed to measure decay heat generation rates of unmodified spent fuel assemblies from commercial nuclear reactors. The system was designed, fabricated, and successfully tested using the following specifications: capacity of one BWR or PWR spent fuel assembly; decay heat generation range 0.1 to 2.5 kW; measurement time of < 12 h; and an accuracy of +-10% or better. The system was acceptance tested using a dc reference heater to simulate spent fuel assembly heat generation rates. Results of these tests indicated that the system could be used to measure heat generation rates between 0.5 and 2.5 kW within +- 5%. Measurements of heat generation rates of approx. 0.1 kW were obtained within +- 15%. The calorimeter system has the potential to permit measurements of heat generation rates of spent fuel assemblies and other devices in the 12- to 14-kW range. Results of calorimetry of a Turkey Point spent fuel assembly indicated that the assembly was generating approx. 1.55 kW.

  16. Volumetric measurements of a spatially growing dust acoustic wave

    Science.gov (United States)

    Williams, Jeremiah D.

    2012-11-01

    In this study, tomographic particle image velocimetry (tomo-PIV) techniques are used to make volumetric measurements of the dust acoustic wave (DAW) in a weakly coupled dusty plasma system in an argon, dc glow discharge plasma. These tomo-PIV measurements provide the first instantaneous volumetric measurement of a naturally occurring propagating DAW. These measurements reveal over the measured volume that the measured wave mode propagates in all three spatial dimensional and exhibits the same spatial growth rate and wavelength in each spatial direction.

  17. Volumetric measurements of a spatially growing dust acoustic wave

    Energy Technology Data Exchange (ETDEWEB)

    Williams, Jeremiah D. [Physics Department, Wittenberg University, Springfield, Ohio 45504 (United States)

    2012-11-15

    In this study, tomographic particle image velocimetry (tomo-PIV) techniques are used to make volumetric measurements of the dust acoustic wave (DAW) in a weakly coupled dusty plasma system in an argon, dc glow discharge plasma. These tomo-PIV measurements provide the first instantaneous volumetric measurement of a naturally occurring propagating DAW. These measurements reveal over the measured volume that the measured wave mode propagates in all three spatial dimensional and exhibits the same spatial growth rate and wavelength in each spatial direction.

  18. Heat transfer and pressure drop characteristics of nanofluids in a plate heat exchanger.

    Science.gov (United States)

    Kwon, Y H; Kim, D; Li, C G; Lee, J K; Hong, D S; Lee, J G; Lee, S H; Cho, Y H; Kim, S H

    2011-07-01

    In this paper, the heat transfer characteristics and pressure drop of the ZnO and Al2O3 nanofluids in a plate heat exchanger were studied. The experimental conditions were 100-500 Reynolds number and the respective volumetric flow rates. The working temperature of the heat exchanger was within 20-40 degrees C. The measured thermophysical properties, such as thermal conductivity and kinematic viscosity, were applied to the calculation of the convective heat transfer coefficient of the plate heat exchanger employing the ZnO and Al2O3 nanofluids made through a two-step method. According to the Reynolds number, the overall heat transfer coefficient for 6 vol% Al2O3 increased to 30% because at the given viscosity and density of the nanofluids, they did not have the same flow rates. At a given volumetric flow rate, however, the performance did not improve. After the nanofluids were placed in the plate heat exchanger, the experimental results pertaining to nanofluid efficiency seemed inauspicious.

  19. Diabatic heating rate estimates from European Centre for Medium-Range Weather Forecasts analyses

    Science.gov (United States)

    Christy, John R.

    1991-01-01

    Vertically integrated diabatic heating rate estimates (H) calculated from 32 months of European Center for Medium-Range Weather Forecasts daily analyses (May 1985-December 1987) are determined as residuals of the thermodynamic equation in pressure coordinates. Values for global, hemispheric, zonal, and grid point H are given as they vary over the time period examined. The distribution of H is compared with previous results and with outgoing longwave radiation (OLR) measurements. The most significant negative correlations between H and OLR occur for (1) tropical and Northern-Hemisphere mid-latitude oceanic areas and (2) zonal and hemispheric mean values for periods less than 90 days. Largest positive correlations are seen in periods greater than 90 days for the Northern Hemispheric mean and continental areas of North Africa, North America, northern Asia, and Antarctica. The physical basis for these relationships is discussed. An interyear comparison between 1986 and 1987 reveals the ENSO signal.

  20. Strengthened PAN-based carbon fibers obtained by slow heating rate carbonization.

    Science.gov (United States)

    Kim, Min-A; Jang, Dawon; Tejima, Syogo; Cruz-Silva, Rodolfo; Joh, Han-Ik; Kim, Hwan Chul; Lee, Sungho; Endo, Morinobu

    2016-03-23

    Large efforts have been made over the last 40 years to increase the mechanical strength of polyacrylonitrile (PAN)-based carbon fibers (CFs) using a variety of chemical or physical protocols. In this paper, we report a new method to increase CFs mechanical strength using a slow heating rate during the carbonization process. This new approach increases both the carbon sp(3) bonding and the number of nitrogen atoms with quaternary bonding in the hexagonal carbon network. Theoretical calculations support a crosslinking model promoted by the interstitial carbon atoms located in the graphitic interlayer spaces. The improvement in mechanical performance by a controlled crosslinking between the carbon hexagonal layers of the PAN based CFs is a new concept that can contribute further in the tailoring of CFs performance based on the understanding of their microstructure down to the atomic scale.

  1. Dependence of the width of the glass transition interval on cooling and heating rates

    Science.gov (United States)

    Schmelzer, Jürn W. P.; Tropin, Timur V.

    2013-01-01

    In a preceding paper [J. W. P. Schmelzer, J. Chem. Phys. 136, 074512 (2012), 10.1063/1.3685510], a general kinetic criterion of glass formation has been advanced allowing one to determine theoretically the dependence of the glass transition temperature on cooling and heating rates (or similarly on the rate of change of any appropriate control parameter determining the transition of a stable or metastable equilibrium system into a frozen-in, non-equilibrium state of the system, a glass). In the present paper, this criterion is employed in order to develop analytical expressions for the dependence of the upper and lower boundaries and of the width of the glass transition interval on the rate of change of the external control parameters. It is shown, in addition, that the width of the glass transition range is strongly correlated with the entropy production at the glass transition temperature. The analytical results are supplemented by numerical computations. Analytical results and numerical computations as well as existing experimental data are shown to be in good agreement.

  2. Resting metabolic rate and heat increment of feeding in juvenile South American fur seals (Arctocephalus australis).

    Science.gov (United States)

    Dassis, M; Rodríguez, D H; Ieno, E N; Denuncio, P E; Loureiro, J; Davis, R W

    2014-02-01

    Bio-energetic models used to characterize an animal's energy budget require the accurate estimate of different variables such as the resting metabolic rate (RMR) and the heat increment of feeding (HIF). In this study, we estimated the in air RMR of wild juvenile South American fur seals (SAFS; Arctocephalus australis) temporarily held in captivity by measuring oxygen consumption while at rest in a postabsorptive condition. HIF, which is an increase in metabolic rate associated with digestion, assimilation and nutrient interconversion, was estimated as the difference in resting metabolic rate between the postabsorptive condition and the first 3.5h postprandial. As data were hierarchically structured, linear mixed effect models were used to compare RMR measures under both physiological conditions. Results indicated a significant increase (61%) for the postprandial RMR compared to the postabsorptive condition, estimated at 17.93±1.84 and 11.15±1.91mL O2 min(-1)kg(-1), respectively. These values constitute the first estimation of RMR and HIF in this species, and should be considered in the energy budgets for juvenile SAFS foraging at-sea.

  3. Volumetric (3D) compressive sensing spectral domain optical coherence tomography.

    Science.gov (United States)

    Xu, Daguang; Huang, Yong; Kang, Jin U

    2014-11-01

    In this work, we proposed a novel three-dimensional compressive sensing (CS) approach for spectral domain optical coherence tomography (SD OCT) volumetric image acquisition and reconstruction. Instead of taking a spectral volume whose size is the same as that of the volumetric image, our method uses a sub set of the original spectral volume that is under-sampled in all three dimensions, which reduces the amount of spectral measurements to less than 20% of that required by the Shan-non/Nyquist theory. The 3D image is recovered from the under-sampled spectral data dimension-by-dimension using the proposed three-step CS reconstruction strategy. Experimental results show that our method can significantly reduce the sampling rate required for a volumetric SD OCT image while preserving the image quality.

  4. A study on alkaline heat treated Mg-Ca alloy for the control of the biocorrosion rate.

    Science.gov (United States)

    Gu, X N; Zheng, W; Cheng, Y; Zheng, Y F

    2009-09-01

    To reduce the biocorrosion rate by surface modification, Mg-Ca alloy (1.4wt.% Ca content) was soaked in three alkaline solutions (Na(2)HPO(4), Na(2)CO(3) and NaHCO(3)) for 24h, respectively, and subsequently heat treated at 773K for 12h. Scanning electron microscopy and energy-dispersive spectroscopy results revealed that magnesium oxide layers with the thickness of about 13, 9 and 26microm were formed on the surfaces of Mg-Ca alloy after the above different alkaline heat treatments. Atomic force microscopy showed that the surfaces of Mg-Ca alloy samples became rough after three alkaline heat treatments. The in vitro corrosion tests in simulated body fluid indicated that the corrosion rates of Mg-Ca alloy were effectively decreased after alkaline heat treatments, with the following sequence: NaHCO(3) heatedheatedheated. The cytotoxicity evaluation revealed that none of the alkaline heat treated Mg-Ca alloy samples induced toxicity to L-929 cells during 7days culture.

  5. Investigations on the heat transport capability of a cryogenic oscillating heat pipe and its application in achieving ultra-fast cooling rates for cell vitrification cryopreservation☆

    OpenAIRE

    Han, Xu; Ma, Hongbin; Jiao, Anjun; Critser, John K.

    2008-01-01

    Theoretically, direct vitrification of cell suspensions with relatively low concentrations (~1 M) of permeating cryoprotective agents (CPA) is suitable for cryopreservation of almost all cell types and can be accomplished by ultra-fast cooling rates that are on the order of 106–7 K/min. However, the methods and devices currently available for cell cryopreservation cannot achieve such high cooling rates. In this study, we constructed a novel cryogenic oscillating heat pipe (COHP) using liquid ...

  6. Volumetric Properties of the Mixture Tetrachloromethane CCl4 + CHCl3 Trichloromethane (VMSD1212, LB4576_V)

    Science.gov (United States)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume C 'Binary Liquid Systems of Nonelectrolytes III' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Volumetric Properties of the Mixture Tetrachloromethane CCl4 + CHCl3 Trichloromethane (VMSD1212, LB4576_V)' providing data by calculation of molar excess volume from low-pressure density measurements at variable mole fraction and constant temperature.

  7. Tick resistance and heat tolerance characteristics in cattle. III. Sweating rate

    Directory of Open Access Journals (Sweden)

    Cecília José Veríssimo

    2012-12-01

    Full Text Available Cattle in a sustainable tropical livestock should be heat tolerant and resistant to ticks. The relationship between Rhipicephalus (Boophilus microplus infestation and sweating rate, an important heat tolerance characteristic, was studied in six Nellore and four Holstein steers of seven-month-old. They were artificial infested (a.i. with 10,000 (Holstein and 20,000 (Nellore larvae in 16/Apr/2011. In days 20, 23 and 24 after the infestation, the 10 bigger females ticks found in whole animal were weighed and put in a chamber (27 oC and 80% RH, weighing the egg mass of each female tick fourteen days after. The sweating rate (SRskin, measured by Scheleger and Turner, 1963, method, in a shaved area of shoulder skin was evaluated in 14/Apr (2 days before the a.i. and in 05/May (19 days after a.i.. In 14/Apr the Scheleger and Turner, 1963, method was done on the coat not shaved (SRcoat. The sweating rate was measured in the afternoon (from 2 P.M., after 30 minutes of direct sunlight, on April. On May, the animals remained 60 minutes in direct sunlight because this day was colder. The experimental design was a non-probability sample restricted to the 10 available animals. Data from the steers’ sweating rate were analyzed using the General linear models of the SPSS® statistical package (version 12.0 using SRskin as dependent variable and breed and sampling date as independent variables. For SRcoat breed was the independent variable. Nellore, a tropical cattle breed, had higher SRskin (1,000.82 ± 64.59 g m-2 h-1, P< 0.001 than Holstein (620.45 ± 79.10 g m-2 h-1. SRskin was higher on May (1,187.33 ± 71.49 g m-2 h-1, P< 0.001 than on April (433.93 ± 71.49 g m-2 h-1. The correlation between the two different measurements of SR was positive and significant (r= 0,545, P<0,01, Pearson correlation. But in SRcoat the breed effect disappeared because the Holstein SRcoat increased (Holstein: 884.95 ± 472.12 g m-2 h-1 and Nellore: 1,060.72 ± 318.21 g m-2 h-1

  8. The effect of heat exposure on cortisol and catecholamine excretion rates in workers in glass manufacturing unit.

    Science.gov (United States)

    Vangelova, K; Deyanov, Ch; Velkova, D; Ivanova, M; Stanchev, V

    2002-12-01

    The aim of the investigation was to study the effect of long term repeated heat exposure on the excretion rates of stress hormones of workers in glass manufacturing unit. Sixteen operators, exposed to heat, were studied during the hot period and compared to a control group of 16 subjects, working in the same manufacturing unit. Both groups had moderate work load. The microclimate components and the Wet Bulb Globe Temperature were used for defining the heat exposure. The excretion rates of cortisol, adrenaline and noradrenaline were followed during the early morning shifts on three hour intervals using RIA and fluoriphotometric methods. Heart rate was followed, too. The psychosocial factors were measured by the "My job" questionnaire. Highly significantly higher cortisol, noradrenaline and adrenaline values were measured in the heat exposed operators compared to the control group, while significant differences of the psychosocial factors between the two groups lacked. Even if the heart rate was in the safe limits, the found alterations in the stress system are considerable and indicate heat stress. The work in conditions of overheat is associated with considerable heat stress and the possible health implications need to be clarified.

  9. Volumetric Three-Dimensional Display Systems

    Science.gov (United States)

    Blundell, Barry G.; Schwarz, Adam J.

    2000-03-01

    A comprehensive study of approaches to three-dimensional visualization by volumetric display systems This groundbreaking volume provides an unbiased and in-depth discussion on a broad range of volumetric three-dimensional display systems. It examines the history, development, design, and future of these displays, and considers their potential for application to key areas in which visualization plays a major role. Drawing substantially on material that was previously unpublished or available only in patent form, the authors establish the first comprehensive technical and mathematical formalization of the field, and examine a number of different volumetric architectures. System level design strategies are presented, from which proposals for the next generation of high-definition predictable volumetric systems are developed. To ensure that researchers will benefit from work already completed, they provide: * Descriptions of several recent volumetric display systems prepared from material supplied by the teams that created them * An abstract volumetric display system design paradigm * An historical summary of 90 years of development in volumetric display system technology * An assessment of the strengths and weaknesses of many of the systems proposed to date * A unified presentation of the underlying principles of volumetric display systems * A comprehensive bibliography Beautifully supplemented with 17 color plates that illustrate volumetric images and prototype displays, Volumetric Three-Dimensional Display Systems is an indispensable resource for professionals in imaging systems development, scientific visualization, medical imaging, computer graphics, aerospace, military planning, and CAD/CAE.

  10. Short communication: Effects of dairy calf hutch elevation on heat reduction, carbon dioxide concentration, air circulation, and respiratory rates.

    Science.gov (United States)

    Moore, D A; Duprau, J L; Wenz, J R

    2012-07-01

    Heat stress affects dairy calf welfare and can result in morbidity, mortality, and lower weight gain. The purpose of this project was to evaluate the effects of elevating the back of plastic calf hutches on measures of ventilation and heat stress. A total of 15 calves housed in individual hutches were enrolled, with each calf hutch serving as its own control. Heat, humidity, carbon dioxide, and wind speed were measured inside each hutch and the observations were compared with external measurements over two 24-h periods; 1 period without and 1 with hutch elevation. Respiratory rates were measured in the morning and afternoon as an indicator of the degree of heat stress experienced by calves with and without elevation of the hutch. When the hutch was elevated, internal hutch temperatures were cooler than external temperatures, hutch carbon dioxide levels were lower and respiratory rates were lower, particularly comparing the afternoon observation periods.

  11. Influence of radiant energy exchange on the determination of convective heat transfer rates to Orbiter leeside surfaces during entry

    Science.gov (United States)

    Throckmorton, D. A.

    1982-01-01

    Temperatures measured at the aerodynamic surface of the Orbiter's thermal protection system (TPS), and calorimeter measurements, are used to determine heating rates to the TPS surface during atmospheric entry. On the Orbiter leeside, where convective heating rates are low, it is possible that a significant portion of the total energy input may result from solar radiation, and for the wing, cross radiation from the hot (relatively) Orbiter fuselage. In order to account for the potential impact of these sources, values of solar- and cross-radiation heat transfer are computed, based upon vehicle trajectory and attitude information and measured surface temperatures. Leeside heat-transfer data from the STS-2 mission are presented, and the significance of solar radiation and fuselage-to-wing cross-radiation contributions to total energy input to Orbiter leeside surfaces is assessed.

  12. Apparatus for measuring the flow rate of a heat carrier and injection wells

    Energy Technology Data Exchange (ETDEWEB)

    Putilov, M.F.; Bar-Sliva, V.I.; Dichenko, M.A.; Nikiforov, Yu.V.; Petrov, A.I.; Turchaninov, Yu.N.

    1981-01-01

    A device is proposed for measuring the flow rate of the heat carrier in N wells, which contains a housing, turbine ( a permanent magnet is attached to the shaft eccentrically), a reed relay, a secondary converter and a power supply. In order to expand the measurement range by developing torque in the turbine it is equipped with additional reed relay, which is installed diametrically opposite the primary reed relay, and it also has a breaking unit made in the form of an additional permanent magnet placed on the turbine shaft. There was also a torodial core with a two-section winding and a winding power supply polarity switch in the frame. The primary and secondary reed relays are connected to the winding power supply polarity switch circuit. It in turn is connected to the secondary converter. In order to assure the possibility of changing the slope of the flow rate converter into a number of turbine revolutions it is equipped with a frequency to voltage converter with a setting mechanism. The frequency to voltage converter input is connected to the secondary converter, and the output is connected to the power supply source.

  13. The effect of heating rate and composition on the properties of spark plasma sintered zirconium diboride based composites

    Energy Technology Data Exchange (ETDEWEB)

    Snyder, Alexandra; Bo Zhenyu [School of Materials Engineering, Purdue University, West Lafayette, IN 47907 (United States); Hodson, Stephen; Fisher, Timothy [School of Mechanical Engineering, Purdue University, West Lafayette, IN 47907 (United States); Stanciu, Lia, E-mail: lstanciu@purdue.edu [School of Materials Engineering, Purdue University, West Lafayette, IN 47907 (United States)

    2012-03-15

    Highlights: Black-Right-Pointing-Pointer We investigated the effect of heating rate on spark plasma sintering of ZrB{sub 2}-SiC-ZrC composites. Black-Right-Pointing-Pointer Adding SiC up to 10 wt.% had a positive effect on densification and strength. Black-Right-Pointing-Pointer Increasing heating rate promoted densification and retarded grain growth when SiC and ZrC content was above 15 wt.%, respectively. Black-Right-Pointing-Pointer Increasing heating rate had a slight negative effect on densification when SiC and ZrC content was at 10%, respectively. - Abstract: Five different compositions of ZrB{sub 2}-SiC-ZrC were prepared and then processed by spark plasma sintering (SPS) to a maximum temperature of 2000 Degree-Sign C, with heating rates of 100 Degree-Sign C/min and 200 Degree-Sign C/min. Grain size, density, Rockwell hardness, flexural strength, and thermal conductivity were evaluated for the processed composites. Adding SiC up to 10 wt.% had a positive effect on densification and strength. Increasing the heating rate promoted densification and less overall grain growth for samples with SiC and ZrC above 15 wt.% each, and had a slight negative effect on densification when these values were at 10%.

  14. Parametric analysis of air–water heat recovery concept applied to HVAC systems: Effect of mass flow rates

    Directory of Open Access Journals (Sweden)

    Mohamad Ramadan

    2015-09-01

    Full Text Available In the last three decades, the world has experienced enormous increases in energy and fuel consumption as a consequence of the economic and population growth. This causes renewable energy and energy recovery to become a requirement in building designs rather than option. The present work concerns a coupling between energy recovery and Heating, Ventilating and Air Conditioning HVAC domains and aims to apply heat recovery concepts to HVAC applications working on refrigeration cycles. It particularly uses the waste energy of the condenser hot air to heat/preheat domestic water. The heat exchanger considered in the recovery system is concentric tube heat exchanger. A thermal modeling of the complete system as well as a corresponding iterative code are developed and presented. Calculations with the code are performed and give pertinent magnitude orders of energy saving and management in HVAC applications. A parametric analysis based on several water and air flow rates is carried out. It was shown that water can be heated from 25 to 70 °C depending on the mass flow rates and cooling loads of the HVAC system. The most efficient configurations are obtained by lowering the air flow rate of the condenser fan.

  15. Radiative energy balance of Venus: An approach to parameterize thermal cooling and solar heating rates

    Science.gov (United States)

    Haus, R.; Kappel, D.; Arnold, G.

    2017-03-01

    Thermal cooling rates QC and solar heating rates QH in the atmosphere of Venus at altitudes between 0 and 100 km are investigated using the radiative transfer and radiative balance simulation techniques described by Haus et al. (2015b, 2016). QC strongly responds to temperature profile and cloud parameter changes, while QH is less sensitive to these parameters. The latter mainly depends on solar insolation conditions and the unknown UV absorber distribution. A parameterization approach is developed that permits a fast and reliable calculation of temperature change rates Q for different atmospheric model parameters and that can be applied in General Circulation Models to investigate atmospheric dynamics. A separation of temperature, cloud parameter, and unknown UV absorber influences is performed. The temperature response parameterization relies on a specific altitude and latitude-dependent cloud model. It is based on an algorithm that characterizes Q responses to a broad range of temperature perturbations at each level of the atmosphere using the Venus International Reference Atmosphere (VIRA) as basis temperature model. The cloud response parameterization considers different temperature conditions and a range of individual cloud mode factors that additionally change cloud optical depths as determined by the initial latitude-dependent model. A QH response parameterization for abundance changes of the unknown UV absorber is also included. Deviations between accurate calculation and parameterization results are in the order of a few tenths of K/day at altitudes below 90 km. The parameterization approach is used to investigate atmospheric radiative equilibrium (RE) conditions. Polar mesospheric RE temperatures above the cloud top are up to 70 K lower and equatorial temperatures up to 10 K higher than observed values. This radiative forcing field is balanced by dynamical processes that maintain the observed thermal structure.

  16. Mixing state of aerosols over the Indo-Gangetic Plain: Radiative forcing and heating rate

    Science.gov (United States)

    Srivastava, R.; Ramachandran, S.

    2012-12-01

    ratio is calculated from the geometry of core-shell particles, which depends on the mass and density of the core and shell. The size distribution parameters and refractive indices of different aerosol species are taken from OPAC database [3]. Different fractions of black carbon, water soluble and mineral dust aerosols involved in core-shell mixing emerge as the most probable mixing states over the IGP. Aerosol forcing for external mixing shows higher deviations from those for probable mixing cases during winter and pre-monsoon. The heating rate over Kanpur and Gandhi College in the lower troposphere is similar during pre-monsoon (March-May) ( 0.75 K day^{-1}) and monsoon (June-September) ( 0.5 K day^{-1}), while differences occur in other seasons [4]. Aerosol heating rate profiles exhibit primary and secondary peaks over the IGP and exhibit seasonal variations. Details on the calculations of aerosol mixing states over IGP, the impact of aerosol mixing state on aerosol forcing and heating rate will be discussed. References: [1] Intergovernmental panel on climate change (2007), Solomon S. et al. (eds.), Cambridge Univ. Press, NewYork. [2] Holben B. N., et al. (2001), J. Geophys. Res., 106(D11), 12067-12097. [3] Hess M., P. Koepke, I. Schult (1998), Bull. Am. Meteorol. Soc., 79, 831-844. [4] Srivastava R., S. Ramachandran (2012), Q. J. R. Meteorol. Soc., 138, doi:10.1002/qj.1958.

  17. Heart rate variability and heat sensation during CT coronary angiography: Low-osmolar versus iso-osmolar contrast media

    Energy Technology Data Exchange (ETDEWEB)

    Svensson, Anders; Ripsweden, Jonaz; Aspelin, Peter; Cederlund, Kerstin; Brismar, B. Torkel (Dept. of Clinical Science, Intervention and Technology, Karolinska Inst., Div. of Medical Imaging and Technology and Dept. of Radiology, Karolinska Univ. Hospital, Huddinge, Stockholm (Sweden)), e-mail: anders.svensson@karolinska.se; Rueck, Andreas (Div. of Cardiology, Dept. of Internal Medicine, Karolinska Inst., Karolinska Univ. Hospital, Stockholm (Sweden))

    2010-09-15

    Background: During computed tomography coronary angiography (CTCA) unexpected changes in heart rate while scanning may affect image quality. Purpose: To evaluate whether an iso-osmolar contrast medium (IOCM, iodixanol) and a low-osmolar contrast medium (LOCM, iomeprol) affect heart rate and experienced heat sensation differently. Material and Methods: One hundred patients scheduled for CTCA were randomized to receive either iodixanol 320 mgI/ml or iomeprol 400 mgI/ml. Depending on their heart rate, the patients were assigned to one of five scanning protocols, each optimized for different heart rate ranges. During scanning the time between each heart beat (hb) was recorded, and the corresponding heart rate was calculated. For each contrast medium (CM) the average heart rate, the variation in heart rate from individual mean heart rate, and the mean deviation from the predefined scanning protocol were calculated. Experience of heat was obtained immediately after scanning by using a visual analog scale (VAS). Examination quality was rated by two radiologists on a three-point scale. Results: The mean variation in heart rate after IOCM was 1.4 hb/min and after LOCM it was 4.4 hb/min (NS). The mean deviations in heart rate from that in the predefined scanning protocol were 2.0 hb/min and 4.7 hb/min, respectively (NS). A greater number of arrhythmic hb were observed after LOCM compared with IOCM (P<0.001). There was no statistically significant difference in image quality. The LOCM group reported a stronger heat sensation after CM injection than the IOCM group (VAS =36 mm and 18 mm, P<0.05). Conclusion: At clinically used concentrations the IOCM, iodixanol 320 mgI/ml, does not increase the heart rate during CTCA and causes less heart arrhythmia and less heat sensation than the LOCM, iomeprol 400 mgI/ml

  18. EXPERIMENTAL STUDY ON PREMIX COMBUSTION AT ISOSCELES TRIANGLE TYPE RATE OF HEAT RELEASE FOR SQUISH TYPE COMBUSTION CHAMBER

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    This paper presents a theory on premix fuel combustion at nearisosceles triangle type rate of heat release,describes the measures taken for the combustion system,points out its many theoretical advantages,and that it can solve effectively the problems of rough running,fuel consumption and exhaust emission.Two squish lip type combustion chambers are designed to match separately with multiple holes injector and conical spray type injector in order to achieve premix combustion at near isosceles triangle type rate of heat release.Experimental studies on two single cylinder diesel engines showed that premix combustion at isosceles triangle type rate of heat release resulted in longer ignition delay period,larger amount of fuel injected into cylinder during the ignition delay period,lower maximum pressure,better fuel economy,and better exhaust emission.

  19. Average Heating Rate of Hot Atmospheres in Distant Clusters by Radio AGN: Evidence for Continuous AGN Heating

    CERN Document Server

    Ma, C -J; Nulsen, P E J; Schaffer, R; Vikhlinin, A

    2011-01-01

    X-ray observations of nearby clusters and galaxies have shown that energetic feedback from active galactic nuclei (AGN) is heating hot atmospheres and is probably the principal agent that is offsetting cooling flows. Here we examine AGN heating in distant X-ray clusters by cross correlating clusters selected from the 400 Square Degree X-ray Cluster survey with radio sources in the NRAO VLA Sky Survey. The jet power for each radio source was determined using scaling relations between radio power and cavity power determined for nearby clusters, groups, and galaxies with atmospheres containing X-ray cavities. Roughly 30% of the clusters show radio emission above a flux threshold of 3 mJy within the central 250 kpc that is presumably associated with the brightest cluster galaxy. We find no significant correlation between radio power, hence jet power, and the X-ray luminosities of clusters in redshift range 0.1 - 0.6. The detection frequency of radio AGN is inconsistent with the presence of strong cooling flows in...

  20. Influence of heat stress on arterial baroreflex control of heart rate in the baboon.

    Science.gov (United States)

    Gorman, A J; Proppe, D W

    1982-07-01

    The influence of environmental heat stress on the arterial baroreflex control of heart rate (HR) was studied in eight conscious, chronically instrumented baboons. Inflations of balloon occluders around the inferior vena cava (IVC) and thoracic descending aorta (DA) were used to produce acute, graded changes in mean arterial blood pressure (MABP) in 5 mm Hg intervals ranging from +/- 5 to +/- 25 mm Hg. After determination of the HR responses to changes in MABP in the normothermic baboon (blood temperature less than or equal to 37.6 degrees C), the animal was subjected to environmental heating to produce hyperthermia. When blood temperature reached approximately 39.5 degrees C, HR responses to graded DA and IVC occlusions were again determined. During hyperthermia, the HR sensitivity (delta HR/ delta MABP) to MABP changes was markedly diminished for reductions in MABP and significantly enhanced for increases in MABP. To determine whether these alterations in the HR response to changes in MABP were due to an alteration of the baroreflex control of HR, full, sigmoid-shaped HR-MABP curves for both the normothermic and hyperthermic states were constructed and characterized by total HR range, estimated slope of the steep portion of the curve, and MABP at the midpoint of the HR range (BP50). During hyperthermia (1) the whole HR-MABP curve shifted significantly upward by 35-40 beats/min, (2) total HR range, the estimated slope, and BP50 did not change, and (3) the control point (pre-occlusion HR-MABP value) curves were also constructed during either beta-adrenergic blockade or cholinergic (Ch)-receptor blockade in the normothermic and hyperthermic state. Similar to that seen for the unblocked heart, the whole HR-MABP curves were also shifted upward during hyperthermia in this group of baboons with no alteration in the total HR range, the estimated slope, or BP50. The upward shift in the HR-MABP curve during Ch-receptor blockade, unlike during beta-receptor blockade, was

  1. Increasing the rate of heating: a potential therapeutic approach for achieving synergistic tumour killing in combined hyperthermia and chemotherapy.

    Science.gov (United States)

    Tang, Yuan; McGoron, Anthony J

    2013-01-01

    A synergistic cancer cell killing effect of sub-lethal hyperthermia and chemotherapy has been reported extensively. In this study, in vitro cell culture experiments with a uterine cancer cell line (MES-SA) and its multidrug resistant (MDR) variant MES-SA/Dx5 were conducted in order to investigate the role of heating rate in achieving a synergistic effect. The mode of cell death, induction of thermal tolerance and P-glycoprotein (P-gp) mediated MDR following two different rates of heating were studied. Doxorubicin (DOX) was used as the chemotherapy drug. A rapid rate hyperthermia was achieved by near infrared laser (NIR) excited indocyanine green (ICG) dye (absorption maximum at 808 nm, ideal for tissue penetration). A slow rate hyperthermia was provided by a cell culture incubator. The potentiating effect of hyperthermia to chemotherapy can be maximised by increasing the rate of heating. When delivered at the same thermal dose, a rapid increase in temperature from 37°C to 43°C caused more cell membrane damage than gradually heating the cells from 37°C to 43°C and thus allowed for more intracellular accumulation of DOX. Meanwhile, the rapid rate laser-ICG hyperthermia at 43°C caused cell necrosis whereas the slow rate incubator hyperthermia at 43°C induced mild apoptosis. At 43°C a positive correlation between thermal tolerance and the length of hyperthermia exposure is identified. This study shows that by increasing the rate of heating, less thermal dose is needed in order to overcome P-gp mediated MDR.

  2. Can Reptile Embryos Influence Their Own Rates of Heating and Cooling?

    OpenAIRE

    Wei-Guo Du; Ming-Chung Tu; Radder, Rajkumar S.; Richard Shine

    2013-01-01

    Previous investigations have assumed that embryos lack the capacity of physiological thermoregulation until they are large enough for their own metabolic heat production to influence nest temperatures. Contrary to intuition, reptile embryos may be capable of physiological thermoregulation. In our experiments, egg-sized objects (dead or infertile eggs, water-filled balloons, glass jars) cooled down more rapidly than they heated up, whereas live snake eggs heated more rapidly than they cooled. ...

  3. On the sensitivity of dimensional stability of high density polyethylene on heating rate

    Directory of Open Access Journals (Sweden)

    2007-02-01

    Full Text Available Although high density polyethylene (HDPE is one of the most widely used industrial polymers, its application compared to its potential has been limited because of its low dimensional stability particularly at high temperature. Dilatometry test is considered as a method for examining thermal dimensional stability (TDS of the material. In spite of the importance of simulation of TDS of HDPE during dilatometry test it has not been paid attention by other investigators. Thus the main goal of this research is concentrated on simulation of TDS of HDPE. Also it has been tried to validate the simulation results and practical experiments. For this purpose the standard dilatometry test was done on the HDPE speci­mens. Secant coefficient of linear thermal expansion was computed from the test. Then by considering boundary conditions and material properties, dilatometry test has been simulated at different heating rates and the thermal strain versus temper­ature was calculated. The results showed that the simulation results and practical experiments were very close together.

  4. Spatial statistical point prediction guidance for heating-rate-limited aeroassisted orbital transfer

    Science.gov (United States)

    Ghosh, Pradipto; Conway, Bruce A.

    2015-06-01

    Feedback control of constrained non-linear dynamical systems satisfying a certain optimality criterion and meeting a specified transfer objective in the state space is recognized as one of the most challenging problems in control theory. One approach to computing optimal feedback policies is the dynamic programming route of numerically solving the Hamilton-Jacobi-Bellman (HJB) partial differential equation directly. In this paper an alternate and more tractable dynamic programming approach, the optimal feedback synthesis method, is utilized. The effectiveness of this method is demonstrated through an explicit guidance scheme for the heating-rate-constrained maneuver of an Aeroassisted Transfer Vehicle (AOTV). In optimal feedback synthesis, a feedback chart is constructed from a family of open-loop extremals, thus ensuring optimality with respect to any initial condition in the family. This paper presents a solution to the AOTV optimal feedback synthesis problem using the Gaussian process spatial prediction method of universal kriging. A closed-form expression for a near-optimal guidance law is derived. Its performance is found to be very promising; initial atmospheric entry errors due to simulated thruster misfiring are seen to be accurately corrected while the algebraic state-inequality constraint is closely respected.

  5. Numerical studies on sizing/ rating of plate fin heat exchangers for a modified Claude cycle based helium liquefier/ refrigerator

    Science.gov (United States)

    Goyal, M.; Chakravarty, A.; Atrey, M. D.

    2017-02-01

    Performance of modern helium refrigeration/ liquefaction systems depends significantly on the effectiveness of heat exchangers. Generally, compact plate fin heat exchangers (PFHE) having very high effectiveness (>0.95) are used in such systems. Apart from basic fluid film resistances, various secondary parameters influence the sizing/ rating of these heat exchangers. In the present paper, sizing calculations are performed, using in-house developed numerical models/ codes, for a set of high effectiveness PFHE for a modified Claude cycle based helium liquefier/ refrigerator operating in the refrigeration mode without liquid nitrogen (LN2) pre-cooling. The combined effects of secondary parameters like axial heat conduction through the heat exchanger metal matrix, parasitic heat in-leak from surroundings and variation in the fluid/ metal properties are taken care of in the sizing calculation. Numerical studies are carried out to predict the off-design performance of the PFHEs in the refrigeration mode with LN2 pre-cooling. Iterative process cycle calculations are also carried out to obtain the inlet/ exit state points of the heat exchangers.

  6. Effects of heating method and conditions on the evaporation rate and quality attributes of black mulberry (Morus nigra) juice concentrate.

    Science.gov (United States)

    Fazaeli, Mahboubeh; Hojjatpanah, Ghazale; Emam-Djomeh, Zahra

    2013-02-01

    Black mulberry juice was concentrated by different heating methods, including conventional heating and microwave heating, at different operational pressures (7.3, 38.5 and 100 kPa). The effects of each method on evaporation rate, quality attributes of concentrated juice were investigated. The final juice concentration of 42° Brix was achieved in 140, 120, and 95 min at 100, 38.5, and 7.3 kPa respectively by using a rotary evaporator. Applying microwave energy decreased required times to 115, 95, and 60 min. The changes in color, anthocyanin content during the concentration processes were investigated. Hunter parameters (L, a, and b) were measured to estimate the intensity of color loss. All Hunter color parameters decreased with time. Results showed that the degradation of color and consequently anthocyanins, was more pronounced in rotary evaporation compared to microwave heating method.

  7. Influence of product thickness, chamber pressure and heating conditions on production rate of freeze-dried yoghurt

    Energy Technology Data Exchange (ETDEWEB)

    Sharma, N.K. [G.B. Pant Univ., of Agriculture and Technology (India). Dept. of Mechanical Engineering; Arora, C.P. [Indian Inst. of Tech., New Delhi (India)

    1995-06-01

    The effects of product thickness, chamber pressure and heating conditions on product temperature profiles and production rate of freeze-dried yoghurt were investigated experimentally. Three sample thicknesses - 3.8 mm, 6.2 mm and 9.4 mm - were tested at chamber pressures of 0.01 and 0.5 mmHg. The production rate increased by decreasing product thickness in contact heating through the bottom of the frozen layer, whereas no significant change was observed in radiant heating. A reduction in chamber pressure from 0.50 to 0.01 mmHg increased the drying time in radiant heating. Maximum production rate was obtained when the thickness of dried product was 6.2 mm, when heat was transferred simultaneously through the frozen and dried layers, and the chamber pressure was at 0.01 mmHg. Use of the product tray developed in this study prevents the growth of dry layers at the contact surfaces. (Author)

  8. Influence of System Variables on the Heating Characteristics of Water during Continuous Flow Microwave Heating

    Directory of Open Access Journals (Sweden)

    Hosahalli S. Ramaswamy

    2011-01-01

    Full Text Available A domestic microwave oven (1000 W was modified to permit the continuous flow of liquids run through a helical coil centrally located inside the oven cavity. Heating characteristics were evaluated by measuring inlet and outlet temperatures of coil as a function of system variables. The influence of number of turns, coil diameter, tube diameter, pitch and initial temperature were evaluated at different flow rates. The average residence time of water was computed by dividing the coil volume by the volumetric flow rate. The influence of Dean number was evaluated. Results from this study showed that (1 higher number of turns resulted in lower heating rate, lower temperature fluctuations, higher exit temperature and longer time to achieve temperature equilibrium; (2 larger tube or coil diameter gave larger coil volume causing the heating rate to decrease; (3 faster flow rates resulted in lower exit temperatures, lower temperature fluctuation, higher Dean number and slightly higher heating rate; (4 higher initial temperatures resulted in higher exit temperatures; (5 higher Dean number resulted in more uniform heating and slightly higher heating rate. Overall, the coil volume was the more dominant factor affecting heating rate as compared with flow rate and Dean number.

  9. Impact of heating rate and solvent on Ni-based catalysts prepared by solution combustion method for syngas methanation

    Directory of Open Access Journals (Sweden)

    Zeng Yan

    2014-12-01

    Full Text Available Ni-Al2O3 catalysts prepared by solution combustion method for syngas methanation were enhanced by employing various heating rate and different solvent. The catalytic properties were tested in syngas methanation. The result indicates that both of heating rate and solvent remarkably affect Ni particle size, which is a key factor to the catalytic activity of Ni-Al2O3 catalysts for syngas methanation. Moreover, the relationship between Ni particle size and the production rate of methane per unit mass was correlated. The optimal Ni-Al2O3 catalyst prepared in ethanol at 2°C/min, achieves a maximum production rate of methane at the mean size of 20.8 nm.

  10. The biophysical and physiological basis for mitigated elevations in heart rate with electric fan use in extreme heat and humidity

    Science.gov (United States)

    Ravanelli, Nicholas M.; Gagnon, Daniel; Hodder, Simon G.; Havenith, George; Jay, Ollie

    2017-02-01

    Electric fan use in extreme heat wave conditions has been thought to be disadvantageous because it might accelerate heat gain to the body via convection. However, it has been recently shown that fan use delays increases in heart rate even at high temperatures (42 °C) in young adults. We here assess the biophysical and physiological mechanisms underlying the apparently beneficial effects of fan use. Eight males (24 ± 3 y; 80.7 ± 11.7 kg; 2.0 ± 0.1 m2) rested at either 36 °C or 42 °C, with (F) or without (NF) electric fan use (4.2 m/s) for 120 min while humidity increased every 7.5 min by 0.3 kPa from a baseline value of 1.6 kPa. Heart rate (HR), local sweat rate (LSR), cutaneous vascular conductance (CVC), core and mean skin temperatures, and the combined convective/radiative heat loss (C+R), evaporative heat balance requirements (Ereq) and maximum evaporative potential (Emax) were assessed. C+R was greater with fan use at 36 °C (F 8 ± 6, NF 2 ± 2 W/m2; P = 0.04) and more negative (greater dry heat gain) with fan use at 42 °C (F -78 ± 4, NF -27 ± 2 W/m2; P prevented by fan use but not without a fan, LSR was higher in NF at both 36 °C ( P = 0.04) and 42 °C ( P = 0.05), and skin temperature was higher in NF at 42 °C ( P = 0.05), but no differences in CVC or core temperatures were observed (all P > 0.05). These results suggest that the delayed increase in heart rate with fan use during extreme heat and humidity is associated with improved evaporative efficiency.

  11. Effect of high heating rate on thermal decomposition behaviour of titanium hydride (TiH2) powder in air

    Indian Academy of Sciences (India)

    A Rasooli; M A Boutorabi; M Divandari; A Azarniya

    2013-04-01

    DTA and TGA curves of titanium hydride powder were determined in air at different heating rates. Also the thermal decomposition behaviour of the aforementioned powder at high heating rates was taken into consideration. A great breakthrough of the practical interest in the research was the depiction of the H2-time curves of TiH2 powder at various temperatures in air. In accordance with the results, an increase in heating rate to higher degrees does not change the process of releasing hydrogen from titanium hydride powder, while switching it from internal diffusion to chemical reaction. At temperatures lower than 600 °C, following the diffusion of hydrogen and oxygen atoms in titanium lattice, thin layers TiH phase and oxides form on the powder surface, controlling the process. On the contrary, from 700 °C later on, the process is controlled by oxidation of titanium hydride powder. In fact, the powder oxidation starts around 650 °C and may escalate following an increase in the heating rate too.

  12. Couette and Poiseuille flows in a low viscosity asthenosphere: Effects of internal heating rate, Rayleigh number, and plate representation

    Science.gov (United States)

    Shiels, C.; Butler, S. L.

    2015-09-01

    Mantle convection models with a low viscosity asthenosphere and high viscosity surface plates have been shown to produce very large aspect ratio convection cells like those inferred to exist in Earth's mantle and to exhibit two asthenospheric flow regimes. When the surface plate is highly mobile, the plate velocity exceeds the flow velocities in the asthenosphere and the plate drives a Couette-type flow in the asthenospheric channel. For sluggish plates, the flow velocities in the asthenosphere exceed the plate velocity and the asthenospheric flow is more Poiseuille-like. It has been shown that under certain circumstances, flows become increasingly Couette-like as the aspect ratio of the plate is increased in numerical simulations. These models also show an increase in the average surface heat flux with aspect ratio which is counterintuitive, as one would expect that large aspect ratio models would result in older and colder oceanic lithosphere. Previous investigations have used single internal heating rates and Rayleigh numbers and a plate formulation that did not preclude significant deformation within the plate. In this paper, we investigate the conditions necessary for Couette and Poiseuille asthenospheric flows and for surface heat flux to increase with plate aspect ratio by varying the internal heating rate, the Rayleigh number and the representation of surface plates in 2D mantle convection models Plates are represented as a high viscosity layer with (1) a free-slip top surface boundary condition and (2) a force-balance boundary condition that imposes a constant surface velocity within the plate. We find that for models with a free-slip surface boundary condition, the internal heating rate and Rayleigh number do not strongly affect the dominance of Couette or Poiseuille flows in the asthenosphere but the increase in surface heat flux with model aspect ratio in the Poiseuille asthenospheric flow regime increases with internal heating rate. For models using

  13. Aerosol Climatology at Pune, Western India: Implications to Direct Radiative Forcing and Heating Rates

    Science.gov (United States)

    Pandithurai, G.; Pinker, R. T.; Devara, P. C.; Raj, P. E.; Jayarao, Y.; Dani, K. K.; Maheskumar, R. S.; Sonbawne, S. M.; Saha, S. K.; Bhawar, R.; Shinde, U. P.

    2005-12-01

    Extensive aerosol observations were carried out at Indian Institute of Tropical Meteorology (IITM), Pune, an urban site in the western part of the country, using a Prede (Model POM-01L) sun/sky radiometer and a bi-static Argon ion lidar since December 2000 and October 1986, respectively. The sun/sky radiometer was operated daily at every 15 minute interval during day-time to derive column aerosol optical parameters such as aerosol optical depth (AOD), single scattering albedo (SSA), asymmetry parameter (ASY) while the lidar was operated weekly in the early-night period to derive vertical distributions of aerosol number density. The sun/sky radiance data collected during the above period have been analysed by using the radiative transfer model SkyRadPack version 3.0 (Nakajima et al. 1996) to retrieve AOD, SSA and ASY. AOD and SSA retrieved at 15-minutes interval were averaged to get monthly means. On every year from 2000 to 2005, monthly means of AOD show gradual increase of aerosol loading from December to April and Angstrom exponent decreases from March due to local as well as transported dust from African / Arabian regions through Arabian Sea. Monthly means of SSA show decrease from December to April and the wavelength dependence also indicate the abundance of dust from March to May. Lidar-derived vertical distributions yield minimum during the monsoon months, gradually builds up during the post-monsoon and winter months, and finally peaks during the pre-monsoon months in every year (Devara et al., 2002). The aerosol climatology of optical/radiative parameters and their vertical distribution are used for estimating aerosol radiative forcing (ARF) and atmospheric heating rates by using a discrete-ordinate radiative transfer model (Ricchiazzi et al., 1998, Pandithurai et al. 2004). Details of the experimental methods, data, results of aerosol climatology and implications to radiative forcing and associated heating rates will be presented. References Devara, P

  14. Near-infrared measurement of water temperature near a 1-mm-diameter magnetic sphere and its heat generation rate under induction heating

    Science.gov (United States)

    Kakuta, Naoto; Nishijima, Keisuke; Kondo, Katsuya; Yamada, Yukio

    2017-07-01

    This paper presents a method of measuring the temperature of water near a 1-mm-diameter magnetic sphere under induction heating. The method is based on the temperature dependence of the absorption coefficient of water at a wavelength of 1150 nm. In this study, two-dimensional images of the absorbance, which is the transverse projection of the absorption coefficient of water, were acquired by a near-infrared camera through a telecentric lens, and three-dimensional radial profiles of the temperature were then generated by applying inverse Abel transforms (IATs) to the absorbance profiles. To ensure the spherical symmetry of the temperature and the parallelity of the light rays, which are the conditions necessary to apply an IAT, the onset of free convection and the angles of deflection were evaluated. This paper also presents a method of estimating the heat generation rate in a sphere by fitting the numerical solutions of the thermal conduction equation to the measured temperatures. The temperatures and heat generation rates were observed to change consistently with the changes in the magnetic field intensity.

  15. Small peripheral lung carcinomas with five-year post-surgical follow-up: assessment by semi-automated volumetric measurement of tumour size, CT value and growth rate on TSCT

    Energy Technology Data Exchange (ETDEWEB)

    Sone, Shusuke [JA Nagano Azumi General Hospital, Ikeda, Nagano (Japan); Nagano Health Promotion Corporation, Inasato, Nagano (Japan); Hanaoka, Takaomi [JA Nagano Azumi General Hospital, Department of Chest Surgery, Ikeda, Nagano (Japan); Ogata, Hiroyuki [JA Nagano Azumi General Hospital, Division of Clinical Laboratory and Pathology, Ikeda, Nagano (Japan); Takayama, Fumiyoshi [JA Nagano Azumi General Hospital, Department of Radiology, Ikeda, Nagano (Japan); Ichinose Neurosurgery Hospital, Matsumoto, Nagano (Japan); Watanabe, Tomofumi [Iida Municipal Hospital, Iida, Nagano (Japan); Haniuda, Masayuki [Aichi Medical University, Division of Chest Surgery, Aichi (Japan); Kaneko, Kazuhiko [Shinshu University School of Medicine, Department of Surgery, Matsumoto (Japan); Okaya-Enrei Hospital, Okaya, Nagano (Japan); Kondo, Ryoichi [National Chushin Matsumoto Hospital, Matsumoto (Japan); Yoshida, Kazuo [Shinshu University School of Medicine, Department of Surgery, Matsumoto (Japan); Honda, Takayuki [Shinshu University School of Medicine, Department of Laboratory Medicine, Matsumoto (Japan)

    2012-01-15

    To retrospectively assess the utility of semi-automated measurements by stratification of CT values of tumour size, CT value and doubling time (DT) using thin-section computed tomography (CT) images. The post-surgical outcomes of favourable and problematic tumours (more advanced p stage than IA, post-surgical recurrence or mortality from lung cancer) were compared using the measured values. The computed DTs were compared with manually measured values. The study subjects comprised 85 patients (aged 33-80 years, 48 women, 37 men), followed-up for more than 5 years postoperatively, with 89 lung lesions, including 17 atypical adenomatous hyperplasias and 72 lung cancers. DTs were determined in 45 lesions. For problematic lesions, whole tumour diameter and density were >18 mm and >-400 HU, respectively. The respective values for the tumour core (with CT values of -350 to 150 HU) were >15 mm and >-70 HU. Analysis of tumour core DTs showed interval tumour progression even if little progress was seen by standard tumour volume DT (TVDT). Software-based volumetric measurements by stratification of CT values provide valuable information on tumour core and help estimate tumour aggressiveness and interval tumour progression better than standard manually measured 2D-VDTs. (orig.)

  16. Investigation of char strength and expansion properties of an intumescent coating exposed to rapid heating rates

    DEFF Research Database (Denmark)

    Nørgaard, Kristian Petersen; Dam-Johansen, Kim; Català, Pere

    2013-01-01

    An efficient and space saving method for passive fire protection is the use of intumescent coatings, which swell when exposed to heat, forming an insulating char layer on top of the virgin coating. Although the temperature curves related to so-called cellulosic fires are often referred to as slow...... heating curves, special cases where the protective char is mechanically damaged and partly removed can cause extremely fast heating of the coating. This situation, for a solvent based intumescent coating, is simulated using direct insertion of free films into a muffle oven. The char formed is evaluated...... with respect to the mechanical resistance against compression, degree of expansion, and residual mass fraction. Experimental results show that when using this type of shock heating, the mechanical resistance of the char against compression cannot meaningfully be correlated to the expansion factor. In addition...

  17. Experimental Study of Single Phase Flow in a Closed-Loop Cooling System with Integrated Mini-Channel Heat Sink

    Directory of Open Access Journals (Sweden)

    Lei Ma

    2016-06-01

    Full Text Available The flow and heat transfer characteristics of a closed-loop cooling system with a mini-channel heat sink for thermal management of electronics is studied experimentally. The heat sink is designed with corrugated fins to improve its heat dissipation capability. The experiments are performed using variable coolant volumetric flow rates and input heating powers. The experimental results show a high and reliable thermal performance using the heat sink with corrugated fins. The heat transfer capability is improved up to 30 W/cm2 when the base temperature is kept at a stable and acceptable level. Besides the heat transfer capability enhancement, the capability of the system to transfer heat for a long distance is also studied and a fast thermal response time to reach steady state is observed once the input heating power or the volume flow rate are varied. Under different input heat source powers and volumetric flow rates, our results suggest potential applications of the designed mini-channel heat sink in cooling microelectronics.

  18. Influence of high temperature pre-deformation on the dissolution rate of delta ferrites in martensitic heat-resistant steels

    Science.gov (United States)

    Li, Junru; Liu, Jianjun; Jiang, Bo; Zhang, Chaolei; Liu, Yazheng

    2017-03-01

    The dissolution process of delta ferrites and the influence of high temperature pre-deformation on the dissolution rate of delta ferrites in martensitic heat-resistant steel 10Cr12Ni3Mo2VN were studied by isothermal heating and thermal simulation experiments. The precipitation temperature of delta ferrites in experimental steel is about 1195 °C. M23C6-type carbides incline to precipitate and coarsen at the boundaries of delta ferrites below 930 °C, and can be rapidly dissolved by heating at 1180 °C. The percentage of delta ferrites gradually decreases with heating time. And a Kolmogorov-Johnson-Mehl-Avrami equation was established to describe the dissolution process of delta ferrites at 1180 °C. High temperature pre-deformation can markedly increase the dissolution rate of delta ferrites. Pre-deformation can largely increase the interface area between delta ferrite and matrix and thus increase the unit-time diffusing quantities of alloying elements between delta ferrites and matrix. In addition, high temperature pre-deformation leads to dynamic recrystallization and increases the number of internal grain boundaries in the delta ferrites. This can also greatly increase the diffusing rate of alloying elements. In these cases, the dissolution of delta ferrites can be promoted.

  19. Effects of Pressure on the Properties of Coal Char Under Gasification Conditions at High Initial Heating Rates

    Science.gov (United States)

    Shurtz, Randy Clark

    The effects of elevated pressure and high heating rates on coal pyrolysis and gasification were investigated. A high-pressure flat-flame burner (HPFFB) was designed and built to conduct these studies. The HPFFB was designed to provide an environment with laminar, dispersed entrained flow, with particle heating rates of ˜105 K/s, pressures of up to 15 atm, and gas temperatures of up to 2000 K. Residence times were varied from 30 to 700 ms in this study. Pyrolysis experiments were conducted at particle heating rates of ˜10 5 K/s and maximum gas temperatures of ˜1700 K at pressures of 1 to 15 atm. A new coal swelling correlation was developed that predicts the effects of heating rate, pressure, and coal rank on the swelling ratio at heating rates above ˜104 K/s. A coal swelling rank index system based on 13C-NMR chemical structural parameters was devised. The empirical swelling model requires user inputs of the coal ultimate and proximate analyses and the use of a transient particle energy balance to predict the maximum particle heating rate. The swelling model was used to explain differences in previously reported bituminous coal swelling ratios that were measured in facilities with different heating rates. Char gasification studies by CO2 were conducted on a subbituminous coal and 4 bituminous coals in the HPFFB. Pressures of 5, 10, and 15 atmospheres were used with gas compositions of 20, 40, and 90 mole % CO2. Gas conditions with peak temperatures of 1700 K to 2000 K were used, which resulted in char particle temperatures of 1000 K to 1800 K. Three gasification models were developed to fit and analyze the gasification data. A simple 1 st--order model was used to show that the measured gasification rates were far below the film-diffusion limit. The other two models, designated CCK and CCKN, were based on three versions of the CBK models. CCKN used an nth--order kinetic mechanism and CCK used a semi-global Langmuir-Hinshelwood kinetic mechanism. The two CCK

  20. Volumetric properties of human islet amyloid polypeptide in liquid water.

    Science.gov (United States)

    Brovchenko, I; Andrews, M N; Oleinikova, A

    2010-04-28

    The volumetric properties of human islet amyloid polypeptide (hIAPP) in water were studied in a wide temperature range by computer simulations. The intrinsic density rho(p) and the intrinsic thermal expansion coefficient alpha(p) of hIAPP were evaluated by taking into account the difference between the volumetric properties of hydration and bulk water. The density of hydration water rho(h) was found to decrease almost linearly with temperature upon heating and its thermal expansion coefficient was found to be notably higher than that of bulk water. The peptide surface exposed to water is more hydrophobic and its rho(h) is smaller in conformation with a larger number of intrapeptide hydrogen bonds. The two hIAPP peptides studied (with and without disulfide bridge) show negative alpha(p), which is close to zero at 250 K and decreases to approximately -1.5 x 10(-3) K(-1) upon heating to 450 K. The analysis of various structural properties of peptides shows a correlation between the intrinsic peptide volumes and the number of intrapeptide hydrogen bonds. The obtained negative values of alpha(p) can be attributed to the shrinkage of the inner voids of the peptides upon heating.

  1. SISGR - In situ characterization and modeling of formation reactions under extreme heating rates in nanostructured multilayer foils

    Energy Technology Data Exchange (ETDEWEB)

    Hufnagel, Todd C.

    2014-06-09

    Materials subjected to extreme conditions, such as very rapid heating, behave differently than materials under more ordinary conditions. In this program we examined the effect of rapid heating on solid-state chemical reactions in metallic materials. One primary goal was to develop experimental techniques capable of observing these reactions, which can occur at heating rates in excess of one million degrees Celsius per second. One approach that we used is x-ray diffraction performed using microfocused x-ray beams and very fast x-ray detectors. A second approach is the use of a pulsed electron source for dynamic transmission electron microscopy. With these techniques we were able to observe how the heating rate affects the chemical reaction, from which we were able to discern general principles about how these reactions proceed. A second thrust of this program was to develop computational tools to help us understand and predict the reactions. From atomic-scale simulations were learned about the interdiffusion between different metals at high heating rates, and about how new crystalline phases form. A second class of computational models allow us to predict the shape of the reaction front that occurs in these materials, and to connect our understanding of interdiffusion from the atomistic simulations to measurements made in the laboratory. Both the experimental and computational techniques developed in this program are expected to be broadly applicable to a wider range of scientific problems than the intermetallic solid-state reactions studied here. For example, we have already begun using the x-ray techniques to study how materials respond to mechanical deformation at very high rates.

  2. Inverse heat transfer problem in digital temperature control in plate fin and tube heat exchangers

    Science.gov (United States)

    Taler, Dawid; Sury, Adam

    2011-12-01

    The aim of the paper is a steady-state inverse heat transfer problem for plate-fin and tube heat exchangers. The objective of the process control is to adjust the number of fan revolutions per minute so that the water temperature at the heat exchanger outlet is equal to a preset value. Two control techniques were developed. The first is based on the presented mathematical model of the heat exchanger while the second is a digital proportional-integral-derivative (PID) control. The first procedure is very stable. The digital PID controller becomes unstable if the water volumetric flow rate changes significantly. The developed techniques were implemented in digital control system of the water exit temperature in a plate fin and tube heat exchanger. The measured exit temperature of the water was very close to the set value of the temperature if the first method was used. The experiments showed that the PID controller works also well but becomes frequently unstable.

  3. Skin blood flow and local temperature independently modify sweat rate during passive heat stress in humans.

    Science.gov (United States)

    Wingo, Jonathan E; Low, David A; Keller, David M; Brothers, R Matthew; Shibasaki, Manabu; Crandall, Craig G

    2010-11-01

    Sweat rate (SR) is reduced in locally cooled skin, which may result from decreased temperature and/or parallel reductions in skin blood flow. The purpose of this study was to test the hypotheses that decreased skin blood flow and decreased local temperature each independently attenuate sweating. In protocols I and II, eight subjects rested supine while wearing a water-perfused suit for the control of whole body skin and internal temperatures. While 34°C water perfused the suit, four microdialysis membranes were placed in posterior forearm skin not covered by the suit to manipulate skin blood flow using vasoactive agents. Each site was instrumented for control of local temperature and measurement of local SR (capacitance hygrometry) and skin blood flow (laser-Doppler flowmetry). In protocol I, two sites received norepinephrine to reduce skin blood flow, while two sites received Ringer solution (control). All sites were maintained at 34°C. In protocol II, all sites received 28 mM sodium nitroprusside to equalize skin blood flow between sites before local cooling to 20°C (2 sites) or maintenance at 34°C (2 sites). In both protocols, individuals were then passively heated to increase core temperature ~1°C. Both decreased skin blood flow and decreased local temperature attenuated the slope of the SR to mean body temperature relationship (2.0 ± 1.2 vs. 1.0 ± 0.7 mg·cm(-2)·min(-1)·°C(-1) for the effect of decreased skin blood flow, P = 0.01; 1.2 ± 0.9 vs. 0.07 ± 0.05 mg·cm(-2)·min(-1)·°C(-1) for the effect of decreased local temperature, P = 0.02). Furthermore, local cooling delayed the onset of sweating (mean body temperature of 37.5 ± 0.4 vs. 37.6 ± 0.4°C, P = 0.03). These data demonstrate that local cooling attenuates sweating by independent effects of decreased skin blood flow and decreased local skin temperature.

  4. Application of multivariate adaptive regression spine-assisted objective function on optimization of heat transfer rate around a cylinder

    Energy Technology Data Exchange (ETDEWEB)

    Dey, Prasenjit; Dad, Ajoy K. [Mechanical Engineering Department, National Institute of Technology, Agartala (India)

    2016-12-15

    The present study aims to predict the heat transfer characteristics around a square cylinder with different corner radii using multivariate adaptive regression splines (MARS). Further, the MARS-generated objective function is optimized by particle swarm optimization. The data for the prediction are taken from the recently published article by the present authors [P. Dey, A. Sarkar, A.K. Das, Development of GEP and ANN model to predict the unsteady forced convection over a cylinder, Neural Comput. Appl. (2015). Further, the MARS model is compared with artificial neural network and gene expression programming. It has been found that the MARS model is very efficient in predicting the heat transfer characteristics. It has also been found that MARS is more efficient than artificial neural network and gene expression programming in predicting the forced convection data, and also particle swarm optimization can efficiently optimize the heat transfer rate.

  5. The effect of ultrasound irradiation on the convective heat transfer rate during immersion cooling of a stationary sphere.

    Science.gov (United States)

    Kiani, Hossein; Sun, Da-Wen; Zhang, Zhihang

    2012-11-01

    It has been proven that ultrasound irradiation can enhance the rate of heat transfer processes. The objective of this work was to study the heat transfer phenomenon, mainly the heat exchange at the surface, as affected by ultrasound irradiation around a stationary copper sphere (k=386W m(-1)K(-1), C(p)=384J kg(-1)K(-1), ρ=8660kg m(-3)) during cooling. The sphere (0.01m in diameter) was immersed in an ethylene glycol-water mixture (-10°C) in an ultrasonic cooling system that included a refrigerated circulator, a flow meter, an ultrasound generator and an ultrasonic bath. The temperature of the sphere was recorded using a data logger equipped with a T-type thermocouple in the center of the sphere. The temperature of the cooling medium was also monitored by four thermocouples situated at different places in the bath. The sphere was located at different positions (0.02, 0.04 and 0.06m) above the transducer surface of the bath calculated considering the center of the sphere as the center of the reference system and was exposed to different intensities of ultrasound (0, 120, 190, 450, 890, 1800, 2800, 3400 and 4100W m(-2)) during cooling. The frequency of the ultrasound was 25kHz. It was demonstrated that ultrasound irradiation can increase the rate of heat transfer significantly, resulting in considerably shorter cooling times. Higher intensities caused higher cooling rates, and Nu values were increased from about 23-27 to 25-108 depending on the intensity of ultrasound and the position of the sphere. However, high intensities of ultrasound led to the generation of heat at the surface of the sphere, thus limiting the lowest final temperature achieved. An analytical solution was developed considering the heat generation and was fitted to the experimental data with R(2) values in the range of 0.910-0.998. Visual observations revealed that both cavitation and acoustic streaming were important for heat transfer phenomenon. Cavitation clouds at the surface of the sphere

  6. Numerical Analysis of Lead-Bismuth-Water Direct Contact Boiling Heat Transfer

    Science.gov (United States)

    Yamada, Yumi; Takahashi, Minoru

    Direct contact boiling heat transfer of sub-cooled water with lead-bismuth eutectic (Pb-Bi) was investigated for the evaluation of the performance of steam generation in direct contact of feed water with primary Pb-Bi coolant in upper plenum above the core in Pb-Bi-cooled direct contact boiling water fast reactor. An analytical two-fluid model was developed to estimate the heat transfer numerically. Numerical results were compared with experimental ones for verification of the model. The overall volumetric heat transfer coefficient was calculated from heat exchange rate in the chimney. It was confirmed that the calculated results agreed well with the experimental result.

  7. Thermal Disk Winds in X-Ray Binaries: Realistic Heating and Cooling Rates Give Rise to Slow, but Massive, Outflows

    Science.gov (United States)

    Higginbottom, N.; Proga, D.; Knigge, C.; Long, K. S.

    2017-02-01

    A number of X-ray binaries exhibit clear evidence for the presence of disk winds in the high/soft state. A promising driving mechanism for these outflows is mass loss driven by the thermal expansion of X-ray heated material in the outer disk atmosphere. Higginbottom & Proga recently demonstrated that the properties of thermally driven winds depend critically on the shape of the thermal equilibrium curve, since this determines the thermal stability of the irradiated material. For a given spectral energy distribution, the thermal equilibrium curve depends on an exact balance between the various heating and cooling mechanisms at work. Most previous work on thermally driven disk winds relied on an analytical approximation to these rates. Here, we use the photoionization code cloudy to generate realistic heating and cooling rates which we then use in a 2.5D hydrodynamic model computed in ZEUS to simulate thermal winds in a typical black hole X-ray binary. We find that these heating and cooling rates produce a significantly more complex thermal equilibrium curve, with dramatically different stability properties. The resulting flow, calculated in the optically thin limit, is qualitatively different from flows calculated using approximate analytical rates. Specifically, our thermal disk wind is much denser and slower, with a mass-loss rate that is a factor of two higher and characteristic velocities that are a factor of three lower. The low velocity of the flow—{v}\\max ≃ 200 km s‑1—may be difficult to reconcile with observations. However, the high mass-loss rate—15 × the accretion rate—is promising, since it has the potential to destabilize the disk. Thermally driven disk winds may therefore provide a mechanism for state changes.

  8. Surfactant enhanced volumetric sweep efficiency

    Energy Technology Data Exchange (ETDEWEB)

    Harwell, J.H.; Scamehorn, J.F.

    1989-10-01

    Surfactant-enhanced waterflooding is a novel EOR method aimed to improve the volumetric sweep efficiencies in reservoirs. The technique depends upon the ability to induce phase changes in surfactant solutions by mixing with surfactants of opposite charge or with salts of appropriate type. One surfactant or salt solution is injected into the reservoir. It is followed later by injection of another surfactant or salt solution. The sequence of injections is arranged so that the two solutions do not mix until they are into the permeable regions well away from the well bore. When they mix at this point, by design they form a precipitate or gel-like coacervate phase, plugging this permeable region, forcing flow through less permeable regions of the reservoir, improving sweep efficiency. The selectivity of the plugging process is demonstrated by achieving permeability reductions in the high permeable regions of Berea sandstone cores. Strategies were set to obtain a better control over the plug placement and the stability of plugs. A numerical simulator has been developed to investigate the potential increases in oil production of model systems. Furthermore, the hardness tolerance of anionic surfactant solutions is shown to be enhanced by addition of monovalent electrolyte or nonionic surfactants. 34 refs., 32 figs., 8 tabs.

  9. NLP modeling for the optimization of LiBr-H2O absorption refrigeration systems with exergy loss rate, heat transfer area, and cost as single objective functions

    DEFF Research Database (Denmark)

    Mussati, Sergio F.; Gernaey, Krist; Morosuk, Tatiana

    2016-01-01

    exergy loss rate, the total heat transfer area, and the total annual cost of the system. It was found that the optimal solution obtained by minimization of the total exergy loss rate provides “theoretical” upper bounds not only for the total heat transfer area of the system but also for each process unit...... and all stream temperatures, while the optimal solution obtained by minimization of the total heat transfer area provides the lower bounds for these model variables, to solve a cost optimization problem. The minimization of the total exergy loss rate by varying parametrically the available total heat...... and quantitatively with increasing available total heat transfer area. These optimization results allowed to find a “practical” value of the total heat transfer area, i.e. no benefits can be obtained by increasing the available total heat transfer area above this value since the minimal total exergy loss value...

  10. Studies on the Effects of Interphase Heat Exchange during Thermal Explosion in a Combustible Dusty Gas with General Arrhenius Reaction-Rate Laws

    OpenAIRE

    K. S. Adegbie; F. I. Alao

    2012-01-01

    A mathematical model for thermal explosion in a combustible dusty gas containing fuel droplets with general Arrhenius reaction-rate laws, convective and radiative heat losses, and interphase heat exchange between gas and inert solid particles is investigated. The objective of the study is to examine the effects of interphase heat exchange between the gas and solid particles on (i) ignition of reacting gas, (ii) accumulation of heat by the solid particles during combustion process (iii) evapor...

  11. Impact of dust aerosols on the radiative budget, surface heat fluxes, heating rate profiles and convective activity over West Africa during March 2006

    Directory of Open Access Journals (Sweden)

    M. Mallet

    2009-09-01

    Full Text Available The present work analyses the effect of dust aerosols on the surface and top of atmosphere radiative budget, surface temperature, sensible heat fluxes, atmospheric heating rate and convective activity over West Africa. The study is focused on the regional impact of a major dust event over the period of 7–14 March 2006 through numerical simulations performed with the mesoscale, nonhydrostatic atmospheric model MesoNH. Due to its importance on radiative budgets, a specific attention has been paid to the representation of dust single scattering albedo (SSA in MesoNH by using inversions of the AErosol RObotic NETwork (AERONET. The radiative impacts are estimated using two parallel simulations, one including radiative effects of dust and the other without them. The simulations of dust aerosol impacts on the radiative budget indicate remarkable instantaneous (at midday decrease of surface shortwave (SW radiations over land, with regional (9°–17° N, 10° W–20° E mean of −137 W/m2 during the 9 to 12 March period. The surface dimming resulting from the presence of dust is shown to cause important reduction of both surface temperature (up to 4°C and sensible heat fluxes (up to 100 W/m2, which is consistent with experimental observations. At the top of the atmosphere, the SW cooling (regional mean of −12.0 W/m2 induced by mineral dust is shown to dominate the total net (shortwave + longwave effect. The maximum SW heating occurs within the dusty layer with values comprised between 4 and 7° K by day and LW effect results in a cooling of −0.10/−0.20° K by day. Finally, the simulations suggest the decrease of the convective available potential energy (CAPE over the region in the presence of mineral dust.

  12. Interaction of heat production, strain rate and stress power in a plastically deforming body under tensile test

    Science.gov (United States)

    Paglietti, A.

    1982-01-01

    At high strain rates the heat produced by plastic deformation can give rise to a rate dependent response even if the material has rate independent constitutive equations. This effect has to be evaluated when interpreting a material test, or else it could erroneously be ascribed to viscosity. A general thermodynamic theory of tensile testing of elastic-plastic materials is given in this paper; it is valid for large strain at finite strain rates. It enables discovery of the parameters governing the thermodynamic strain rate effect, provides a method for proper interpretation of the results of the tests of dynamic plasticity, and suggests a way of planning experiments in order to detect the real contribution of viscosity.

  13. Interaction of heat production, strain rate and stress power in a plastically deforming body under tensile test

    Science.gov (United States)

    Paglietti, A.

    1982-01-01

    At high strain rates the heat produced by plastic deformation can give rise to a rate dependent response even if the material has rate independent constitutive equations. This effect has to be evaluated when interpreting a material test, or else it could erroneously be ascribed to viscosity. A general thermodynamic theory of tensile testing of elastic-plastic materials is given in this paper; it is valid for large strain at finite strain rates. It enables discovery of the parameters governing the thermodynamic strain rate effect, provides a method for proper interpretation of the results of the tests of dynamic plasticity, and suggests a way of planning experiments in order to detect the real contribution of viscosity.

  14. Subjective ratings and performance in the heat and after sleep deprivation

    NARCIS (Netherlands)

    Daanen, H.A.M.; Ling, S. van; Tan, T.K.

    2013-01-01

    Background: It has been shown that endurance performance after one night of sleep deprivation is not compromised despite the feeling of fatigue and that, in contrast, performance in the heat deteriorates even though people may feel good. However, it is essentially unknown how the estimation of perfo

  15. Apparent activation energy for densification of -Al2O3 powder at constant heating-rate sintering

    Indian Academy of Sciences (India)

    W Q Shao; S O Chen; D Li; H S Cao; Y C Zhang; S S Zhang

    2008-11-01

    The apparent activation energy for densification is a characteristic quantity that elucidates the fundamental diffusion mechanisms during the sintering process. Based on the Arrhenius theory, the activation energy for densification of -Al2O3 at constant heating-rates sintering has been estimated. Sintering of -Al2O3 powder has been executed by the way of a push rod type dilatometer. It is shown that the apparent activation energy does not have a single value but depends directly on the relative density. The apparent activation energy corresponding to lower relative density was higher than that corresponding to higher relative density. In addition, the value of the evaluated activation energy is different at the same density level when the Arrhenius plot involves different heating rates.

  16. Effect of cooling-heating rate on sol-gel transformation of fish gelatin-gum arabic complex coacervate phase.

    Science.gov (United States)

    Anvari, Mohammad; Chung, Donghwa

    2016-10-01

    The objective of this study was to characterize influence of different cooling and heating rates on gelation of fish gelatin (FG)-gum arabic (GA) complex coacervate phase using rheological measurements. For the coacervate phase prepared at 10°C, the gelling temperature, melting temperature, gel strength, and stress relaxation decreased with increasing cooling or heating rate, however, no gelation was observed at the highest cooling rate of 0.05°C/min. Similar trends were obtained for the coacervates phase prepared at 30°C, but the gelation did not occur at a cooling rate of 0.033 or 0.05°C/min. The results indicated that rheological properties of FG-GA coacervate gels were highly dependent to the cooling process, where more thermos-stable and stronger gels formed at slower cooling. This was probably because of higher degree of molecular rearrangements, more hydrogen bindings, and formation of greater junction zones into the gel network at slower cooling rates. However, all of the FG-GA coacervate gels obtained at different cooling rates were classified as a weak physical gel.

  17. Vertical profiles of aerosol optical properties and the solar heating rate estimated by combining sky radiometer and lidar measurements

    Science.gov (United States)

    Kudo, Rei; Nishizawa, Tomoaki; Aoyagi, Toshinori

    2016-07-01

    The SKYLIDAR algorithm was developed to estimate vertical profiles of aerosol optical properties from sky radiometer (SKYNET) and lidar (AD-Net) measurements. The solar heating rate was also estimated from the SKYLIDAR retrievals. The algorithm consists of two retrieval steps: (1) columnar properties are retrieved from the sky radiometer measurements and the vertically mean depolarization ratio obtained from the lidar measurements and (2) vertical profiles are retrieved from the lidar measurements and the results of the first step. The derived parameters are the vertical profiles of the size distribution, refractive index (real and imaginary parts), extinction coefficient, single-scattering albedo, and asymmetry factor. Sensitivity tests were conducted by applying the SKYLIDAR algorithm to the simulated sky radiometer and lidar data for vertical profiles of three different aerosols, continental average, transported dust, and pollution aerosols. The vertical profiles of the size distribution, extinction coefficient, and asymmetry factor were well estimated in all cases. The vertical profiles of the refractive index and single-scattering albedo of transported dust, but not those of transported pollution aerosol, were well estimated. To demonstrate the performance and validity of the SKYLIDAR algorithm, we applied the SKYLIDAR algorithm to the actual measurements at Tsukuba, Japan. The detailed vertical structures of the aerosol optical properties and solar heating rate of transported dust and smoke were investigated. Examination of the relationship between the solar heating rate and the aerosol optical properties showed that the vertical profile of the asymmetry factor played an important role in creating vertical variation in the solar heating rate. We then compared the columnar optical properties retrieved with the SKYLIDAR algorithm to those produced with the more established scheme SKYRAD.PACK, and the surface solar irradiance calculated from the SKYLIDAR

  18. Prediction of heating rate controlled viscous flow activation energy during spark plasma sintering of amorphous alloy powders

    Science.gov (United States)

    Paul, Tanaji; Harimkar, Sandip P.

    2017-07-01

    The viscous flow behavior of Fe-based amorphous alloy powder during isochronal spark plasma sintering was analyzed under the integrated theoretical background of the Arrhenius and directional structural relaxation models. A relationship between viscous flow activation energy and heating rate was derived. An extension of the pertinent analysis to Ti-based amorphous alloys confirmed the broad applicability of such a relationship for predicting the activation energy for sintering below the glass transition temperature (T g) of the amorphous alloy powders.

  19. Effect of heating rate and kinetic model selection on activation energy of nonisothermal crystallization of amorphous felodipine.

    Science.gov (United States)

    Chattoraj, Sayantan; Bhugra, Chandan; Li, Zheng Jane; Sun, Changquan Calvin

    2014-12-01

    The nonisothermal crystallization kinetics of amorphous materials is routinely analyzed by statistically fitting the crystallization data to kinetic models. In this work, we systematically evaluate how the model-dependent crystallization kinetics is impacted by variations in the heating rate and the selection of the kinetic model, two key factors that can lead to significant differences in the crystallization activation energy (Ea ) of an amorphous material. Using amorphous felodipine, we show that the Ea decreases with increase in the heating rate, irrespective of the kinetic model evaluated in this work. The model that best describes the crystallization phenomenon cannot be identified readily through the statistical fitting approach because several kinetic models yield comparable R(2) . Here, we propose an alternate paired model-fitting model-free (PMFMF) approach for identifying the most suitable kinetic model, where Ea obtained from model-dependent kinetics is compared with those obtained from model-free kinetics. The most suitable kinetic model is identified as the one that yields Ea values comparable with the model-free kinetics. Through this PMFMF approach, nucleation and growth is identified as the main mechanism that controls the crystallization kinetics of felodipine. Using this PMFMF approach, we further demonstrate that crystallization mechanism from amorphous phase varies with heating rate. © 2014 Wiley Periodicals, Inc. and the American Pharmacists Association.

  20. Experimental study on heat transfer enhancement of a helically baffled heat exchanger combined with three-dimensional finned tubes

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Zhnegguo; Xu Tao; Fang Xiaoming [South China University of Technology, Guangzhou (China). Ministry of Education

    2004-10-01

    Heat transfer and pressure drop of helically baffled heat exchanger combined with petal-shaped finned tubes for oil (ISO VG-32) cooling with water as coolant was experimentally studied. The tube side heat transfer coefficient was obtained by a modified Wilson plot technique. Results were presented as plots of the shell side heat transfer coefficient based on the actual outside surface area of tube bundle and pressure drop against volumetric flow rate of oil. Under experimental conditions, the maximum shell side heat transfer coefficient is 2265 W/m{sup 2} K, the corresponding shell side pressure drop is 91 kPa. The preliminary heat transfer enhancement mechanisms were discussed for oil flow helically on outside surface of petal-shaped finned tubes. (author)

  1. Pulse sequence for dynamic volumetric imaging of hyperpolarized metabolic products

    Science.gov (United States)

    Cunningham, Charles H.; Chen, Albert P.; Lustig, Michael; Hargreaves, Brian A.; Lupo, Janine; Xu, Duan; Kurhanewicz, John; Hurd, Ralph E.; Pauly, John M.; Nelson, Sarah J.; Vigneron, Daniel B.

    2008-07-01

    Dynamic nuclear polarization and dissolution of a 13C-labeled substrate enables the dynamic imaging of cellular metabolism. Spectroscopic information is typically acquired, making the acquisition of dynamic volumetric data a challenge. To enable rapid volumetric imaging, a spectral-spatial excitation pulse was designed to excite a single line of the carbon spectrum. With only a single resonance present in the signal, an echo-planar readout trajectory could be used to resolve spatial information, giving full volume coverage of 32 × 32 × 16 voxels every 3.5 s. This high frame rate was used to measure the different lactate dynamics in different tissues in a normal rat model and a mouse model of prostate cancer.

  2. Magnetic Resonance Image Segmentation and its Volumetric Measurement

    Directory of Open Access Journals (Sweden)

    Rahul R. Ambalkar

    2013-02-01

    Full Text Available Image processing techniques make it possible to extract meaningful information from medical images. Magnetic resonance (MR imaging has been widely applied in biological research and diagnostics because of its excellent soft tissue contrast, non-invasive character, high spatial resolution and easy slice selection at any orientation. The MRI-based brain volumetric is concerned with the analysis of volumes and shapes of the structural components of the human brain. It also provides a criterion, by which we recognize the presence of degenerative diseases and characterize their rates of progression to make the diagnosis and treatments as a easy task. In this paper we have proposed an automated method for volumetric measurement of Magnetic Resonance Imaging and used Self Organized Map (SOM clustering method for their segmentations. We have used the MRI data set of 61 slices of 256×256 pixels in DICOM standard format

  3. Two-dimensional random arrays for real time volumetric imaging

    DEFF Research Database (Denmark)

    Davidsen, Richard E.; Jensen, Jørgen Arendt; Smith, Stephen W.

    1994-01-01

    Two-dimensional arrays are necessary for a variety of ultrasonic imaging techniques, including elevation focusing, 2-D phase aberration correction, and real time volumetric imaging. In order to reduce system cost and complexity, sparse 2-D arrays have been considered with element geometries...... real time volumetric imaging system, which employs a wide transmit beam and receive mode parallel processing to increase image frame rate. Depth-of-field comparisons were made from simulated on-axis and off-axis beamplots at ranges from 30 to 160 mm for both coaxial and offset transmit and receive...... selected ad hoc, by algorithm, or by random process. Two random sparse array geometries and a sparse array with a Mills cross receive pattern were simulated and compared to a fully sampled aperture with the same overall dimensions. The sparse arrays were designed to the constraints of the Duke University...

  4. In Vivo Real Time Volumetric Synthetic Aperture Ultrasound Imaging

    DEFF Research Database (Denmark)

    Bouzari, Hamed; Rasmussen, Morten Fischer; Brandt, Andreas Hjelm

    2015-01-01

    . This paper investigates the in vivo applicability and sensitivity of volumetric SA imaging. Utilizing the transmit events to generate a set of virtual point sources, a frame rate of 25 Hz for a 90° x 90° field-of-view was achieved. Data were obtained using a 3.5 MHz 32 x 32 elements 2-D phased array......Synthetic aperture (SA) imaging can be used to achieve real-time volumetric ultrasound imaging using 2-D array transducers. The sensitivity of SA imaging is improved by maximizing the acoustic output, but one must consider the limitations of an ultrasound system, both technical and biological...... transducer connected to the experimental scanner (SARUS). Proper scaling is applied to the excitation signal such that intensity levels are in compliance with the U.S. Food and Drug Administration regulations for in vivo ultrasound imaging. The measured Mechanical Index and spatial-peak- temporal...

  5. Laser Based 3D Volumetric Display System

    Science.gov (United States)

    1993-03-01

    Literature, Costa Mesa, CA July 1983. 3. "A Real Time Autostereoscopic Multiplanar 3D Display System", Rodney Don Williams, Felix Garcia, Jr., Texas...8217 .- NUMBERS LASER BASED 3D VOLUMETRIC DISPLAY SYSTEM PR: CD13 0. AUTHOR(S) PE: N/AWIU: DN303151 P. Soltan, J. Trias, W. Robinson, W. Dahlke 7...laser generated 3D volumetric images on a rotating double helix, (where the 3D displays are computer controlled for group viewing with the naked eye

  6. GLOBAL EXISTENCE AND CONVERGENCE RATES OF SMOOTH SOLUTIONS FOR THE 3-D COMPRESSIBLE MAGNETOHYDRODYNAMIC EQUATIONS WITHOUT HEAT CONDUCTIVITY

    Institute of Scientific and Technical Information of China (English)

    Zhensheng GAO; Zhong TAN; Guochun WU

    2014-01-01

    In this paper, we are concerned with the global existence and convergence rates of the smooth solutions for the compressible magnetohydrodynamic equations without heat conductivity, which is a hyperbolic-parabolic system. The global solutions are obtained by combining the local existence and a priori estimates if H3-norm of the initial perturbation around a constant states is small enough and its L1-norm is bounded. A priori decay-in-time estimates on the pressure, velocity and magnetic field are used to get the uniform bound of entropy. Moreover, the optimal convergence rates are also obtained.

  7. Diagnostics of Coronal Heating in Active-region Loops

    Science.gov (United States)

    Fludra, A.; Hornsey, C.; Nakariakov, V. M.

    2017-01-01

    Understanding coronal heating remains a central problem in solar physics. Many mechanisms have been proposed to explain how energy is transferred to and deposited in the corona. We summarize past observational studies that attempted to identify the heating mechanism and point out the difficulties in reproducing the observations of the solar corona from the heating models. The aim of this paper is to study whether the observed extreme ultraviolet (EUV) emission in individual coronal loops in solar active regions can provide constraints on the volumetric heating function, and to develop a diagnostic for the heating function for a subset of loops that are found close to static thermal equilibrium. We reconstruct the coronal magnetic field from Solar Dynamics Observatory/HMI data using a nonlinear force-free magnetic field model. We model selected loops using a one-dimensional stationary model, with a heating rate dependent locally on the magnetic field strength along the loop, and we calculate the emission from these loops in various EUV wavelengths for different heating rates. We present a method to measure a power index β defining the dependence of the volumetric heating rate EH on the magnetic field, {E}H\\propto {B}β , and controlling also the shape of the heating function: concentrated near the loop top, uniform and concentrated near the footpoints. The diagnostic is based on the dependence of the electron density on the index β. This method is free from the assumptions of the loop filling factor but requires spectroscopic measurements of the density-sensitive lines. The range of applicability for loops of different length and heating distributions is discussed, and the steps to solving the coronal heating problem are outlined.

  8. The effect of heat developed during high strain rate deformation on the constitutive modeling of amorphous polymers

    Science.gov (United States)

    Safari, Keivan H.; Zamani, Jamal; Guedes, Rui M.; Ferreira, Fernando J.

    2016-02-01

    An adiabatic constitutive model is proposed for large strain deformation of polycarbonate (PC) at high strain rates. When the strain rate is sufficiently high such that the heat generated does not have time to transfer to the surroundings, temperature of material rises. The high strain rate deformation behavior of polymers is significantly affected by temperature-dependent constants and thermal softening. Based on the isothermal model which first was introduced by Mulliken and Boyce et al. (Int. J. Solids Struct. 43:1331-1356, 2006), an adiabatic model is proposed to predict the yield and post-yield behavior of glassy polymers at high strain rates. When calculating the heat generated and the temperature changes during the step by step simulation of the deformation, temperature-dependent elastic constants are incorporated to the constitutive equations. Moreover, better prediction of softening phenomena is achieved by the new definition for softening parameters of the proposed model. The constitutive model has been implemented numerically into a commercial finite element code through a user material subroutine (VUMAT). The experimental results, obtained using a split Hopkinson pressure bar, are supported by dynamic mechanical thermal analysis (DMTA) and Decompose/Shift/Reconstruct (DSR) method. Comparison of adiabatic model predictions with experimental data demonstrates the ability of the model to capture the characteristic features of stress-strain curve of the material at very high strain rates.

  9. Transient Simulation Of A Solar-Hybrid Tower Power Plant With Open Volumetric Receiver At The Location Barstow

    OpenAIRE

    2013-01-01

    In this work the transient simulations of four hybrid solar tower power plant concepts with open-volumetric receiver technology for a location in Barstow-Daggett, USA, are presented. The open-volumetric receiver uses ambient air as heat transfer fluid and the hybridization is realized with a gas turbine. The Rankine cycle is heated by solar-heated air and/or by the gas turbine’s flue gases. The plant can be operated in solar-only, hybrid parallel or combined cycle-only mode as well a...

  10. Volumetric Properties of the Mixture Trichloromethane CHCl3 + C4H10O Diethyl ether (VMSD1211, LB3412_V)

    Science.gov (United States)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume C 'Binary Liquid Systems of Nonelectrolytes III' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Volumetric Properties of the Mixture Trichloromethane CHCl3 + C4H10O Diethyl ether (VMSD1211, LB3412_V)' providing data from direct low-pressure dilatometric measurement of molar excess volume at variable mole fraction and constant temperature.

  11. Volumetric Properties of the Mixture Trichloromethane CHCl3 + C8H16 Cyclooctane (VMSD1211, LB3565_V)

    Science.gov (United States)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume B 'Binary Liquid Systems of Nonelectrolytes II' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Volumetric Properties of the Mixture Trichloromethane CHCl3 + C8H16 Cyclooctane (VMSD1211, LB3565_V)' providing data from direct low-pressure dilatometric measurement of molar excess volume at variable mole fraction and constant temperature.

  12. Volumetric Properties of the Mixture Trichloromethane CHCl3 + C5H10O Oxane (VMSD1212, LB3577_V)

    Science.gov (United States)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume C 'Binary Liquid Systems of Nonelectrolytes III' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Volumetric Properties of the Mixture Trichloromethane CHCl3 + C5H10O Oxane (VMSD1212, LB3577_V)' providing data by calculation of molar excess volume from low-pressure density measurements at variable mole fraction and constant temperature.

  13. Volumetric Properties of the Mixture Trichloromethane CHCl3 + C4H8O Oxolane (VMSD1212, LB3576_V)

    Science.gov (United States)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume C 'Binary Liquid Systems of Nonelectrolytes III' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Volumetric Properties of the Mixture Trichloromethane CHCl3 + C4H8O Oxolane (VMSD1212, LB3576_V)' providing data by calculation of molar excess volume from low-pressure density measurements at variable mole fraction and constant temperature.

  14. Volumetric Properties of the Mixture Trichloromethane CHCl3 + C6H14 Hexane (VMSD1211, LB4339_V)

    Science.gov (United States)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume B 'Binary Liquid Systems of Nonelectrolytes II' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Volumetric Properties of the Mixture Trichloromethane CHCl3 + C6H14 Hexane (VMSD1211, LB4339_V)' providing data from direct low-pressure dilatometric measurement of molar excess volume at variable mole fraction and constant temperature.

  15. Volumetric Properties of the Mixture Trichloromethane CHCl3 + C6H12 Cyclohexane (VMSD1211, LB3566_V)

    Science.gov (United States)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume A 'Binary Liquid Systems of Nonelectrolytes I' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Volumetric Properties of the Mixture Trichloromethane CHCl3 + C6H12 Cyclohexane (VMSD1211, LB3566_V)' providing data from direct low-pressure dilatometric measurement of molar excess volume at variable mole fraction and constant temperature.

  16. Volumetric Properties of the Mixture Trichloromethane CHCl3 + C6H7N Aniline (VMSD1211, LB4340_V)

    Science.gov (United States)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume C 'Binary Liquid Systems of Nonelectrolytes III' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Volumetric Properties of the Mixture Trichloromethane CHCl3 + C6H7N Aniline (VMSD1211, LB4340_V)' providing data from direct low-pressure dilatometric measurement of molar excess volume at variable mole fraction and constant temperature.

  17. Volumetric Properties of the Mixture Trichloromethane CHCl3 + C5H10 Cyclopentane (VMSD1211, LB3567_V)

    Science.gov (United States)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume A 'Binary Liquid Systems of Nonelectrolytes I' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Volumetric Properties of the Mixture Trichloromethane CHCl3 + C5H10 Cyclopentane (VMSD1211, LB3567_V)' providing data from direct low-pressure dilatometric measurement of molar excess volume at variable mole fraction and constant temperature.

  18. Volumetric Properties of the Mixture Trichloromethane CHCl3 + C2H6S 2-Thiapropane (VMSD1211, LB3233_V)

    Science.gov (United States)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume C 'Binary Liquid Systems of Nonelectrolytes III' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Volumetric Properties of the Mixture Trichloromethane CHCl3 + C2H6S 2-Thiapropane (VMSD1211, LB3233_V)' providing data from direct low-pressure dilatometric measurement of molar excess volume at variable mole fraction and constant temperature.

  19. Volumetric Properties of the Mixture Trichloromethane CHCl3 + C2H6OS Dimethyl sulfoxide (VMSD1211, LB3256_V)

    Science.gov (United States)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume C 'Binary Liquid Systems of Nonelectrolytes III' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Volumetric Properties of the Mixture Trichloromethane CHCl3 + C2H6OS Dimethyl sulfoxide (VMSD1211, LB3256_V)' providing data from direct low-pressure dilatometric measurement of molar excess volume at variable mole fraction and constant temperature.

  20. Volumetric Properties of the Mixture Trichloromethane CHCl3 + CH2Cl2 Dichloromethane (VMSD1212, LB4574_V)

    Science.gov (United States)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume A 'Binary Liquid Systems of Nonelectrolytes I' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Volumetric Properties of the Mixture Trichloromethane CHCl3 + CH2Cl2 Dichloromethane (VMSD1212, LB4574_V)' providing data by calculation of molar excess volume from low-pressure density measurements at variable mole fraction and constant temperature.

  1. Volumetric Properties of the Mixture Trichloromethane CHCl3 + C6H6 Benzene (VMSD1212, LB3207_V)

    Science.gov (United States)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume A 'Binary Liquid Systems of Nonelectrolytes I' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Volumetric Properties of the Mixture Trichloromethane CHCl3 + C6H6 Benzene (VMSD1212, LB3207_V)' providing data by calculation of molar excess volume from low-pressure density measurements at variable mole fraction and constant temperature.

  2. Volumetric Properties of the Mixture Trichloromethane CHCl3 + C2H3N Ethanenitrile (VMSD1212, LB4352_V)

    Science.gov (United States)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume C 'Binary Liquid Systems of Nonelectrolytes III' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Volumetric Properties of the Mixture Trichloromethane CHCl3 + C2H3N Ethanenitrile (VMSD1212, LB4352_V)' providing data by calculation of molar excess volume from low-pressure density measurements at variable mole fraction and constant temperature.

  3. Volumetric Properties of the Mixture Trichloromethane CHCl3 + C4H10S 3-Thiapentane (VMSD1211, LB3237_V)

    Science.gov (United States)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume C 'Binary Liquid Systems of Nonelectrolytes III' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Volumetric Properties of the Mixture Trichloromethane CHCl3 + C4H10S 3-Thiapentane (VMSD1211, LB3237_V)' providing data from direct low-pressure dilatometric measurement of molar excess volume at variable mole fraction and constant temperature.

  4. Correlation of Heating Rates, Crystal Structures, and Microwave Dielectric Properties of Li2ZnTi3O8 Ceramics

    Science.gov (United States)

    Lu, Xuepeng; Zheng, Yong; Huang, Qi; Xiong, Weihao

    2015-11-01

    The correlation of heating rates, crystal structures, and microwave dielectric properties of Li2ZnTi3O8 ceramics was thoroughly investigated. Ionic polarizability, atomic packing fractions, bond strengths, and octahedral distortion of Li2ZnTi3O8 ceramics were calculated on the basis of structure refinement data. The "black core" phenomenon resulting from reduction of Ti4+ ions was observed for Li2ZnTi3O8 ceramic sintered at 1°/min; reduction of Ti4+ ions could be limited by heating more rapidly. For heating rates from 1 to 7°/min, the dielectric constants ( ɛ r) of Li2ZnTi3O8 ceramics were mainly determined by ionic polarizability. The temperature coefficient of the resonant frequency ( τ f ) of Li2ZnTi3O8 ceramics was determined by bond strengths. Li2ZnTi3O8 ceramic sintered at 1°/min had the lowest quality factor ( Q × f); this was related to the high dielectric loss as a result of oxygen vacancies formed by reduction of Ti4+ ions. Q × f values of Li2ZnTi3O8 ceramics also decreased with increasing heating rate from 3 to 7°/min, owing to reduced packing fractions and average grain sizes. Li2ZnTi3O8 ceramic sintered at 3°/min had the optimum microwave dielectric properties of ɛ r = 26.6, Q × f = 83,563 GHz, and τ f = -12.4 ppm/°C.

  5. Impact of the High Flux Isotope Reactor HEU to LEU Fuel Conversion on Cold Source Nuclear Heat Generation Rates

    Energy Technology Data Exchange (ETDEWEB)

    Chandler, David [ORNL

    2014-03-01

    Under the sponsorship of the US Department of Energy National Nuclear Security Administration, staff members at the Oak Ridge National Laboratory have been conducting studies to determine whether the High Flux Isotope Reactor (HFIR) can be converted from high enriched uranium (HEU) fuel to low enriched uranium (LEU) fuel. As part of these ongoing studies, an assessment of the impact that the HEU to LEU fuel conversion has on the nuclear heat generation rates in regions of the HFIR cold source system and its moderator vessel was performed and is documented in this report. Silicon production rates in the cold source aluminum regions and few-group neutron fluxes in the cold source moderator were also estimated. Neutronics calculations were performed with the Monte Carlo N-Particle code to determine the nuclear heat generation rates in regions of the HFIR cold source and its vessel for the HEU core operating at a full reactor power (FP) of 85 MW(t) and the reference LEU core operating at an FP of 100 MW(t). Calculations were performed with beginning-of-cycle (BOC) and end-of-cycle (EOC) conditions to bound typical irradiation conditions. Average specific BOC heat generation rates of 12.76 and 12.92 W/g, respectively, were calculated for the hemispherical region of the cold source liquid hydrogen (LH2) for the HEU and LEU cores, and EOC heat generation rates of 13.25 and 12.86 W/g, respectively, were calculated for the HEU and LEU cores. Thus, the greatest heat generation rates were calculated for the EOC HEU core, and it is concluded that the conversion from HEU to LEU fuel and the resulting increase of FP from 85 MW to 100 MW will not impact the ability of the heat removal equipment to remove the heat deposited in the cold source system. Silicon production rates in the cold source aluminum regions are estimated to be about 12.0% greater at BOC and 2.7% greater at EOC for the LEU core in comparison to the HEU core. Silicon is aluminum s major transmutation product and

  6. Impact of turbocharger non-adiabatic operation on engine volumetric efficiency and turbo lag

    OpenAIRE

    S. Shaaban; Seume, J.

    2012-01-01

    Turbocharger performance significantly affects the thermodynamic properties of the working fluid at engine boundaries and hence engine performance. Heat transfer takes place under all circumstances during turbocharger operation. This heat transfer affects the power produced by the turbine, the power consumed by the compressor, and the engine volumetric efficiency. Therefore, non-adiabatic turbocharger performance can restrict the engine charging process and hence engine performance. The prese...

  7. Impact of Turbocharger Non-Adiabatic Operation on Engine Volumetric Efficiency and Turbo Lag

    OpenAIRE

    S. Shaaban; Seume, J.

    2012-01-01

    Turbocharger performance significantly affects the thermodynamic properties of the working fluid at engine boundaries and hence engine performance. Heat transfer takes place under all circumstances during turbocharger operation. This heat transfer affects the power produced by the turbine, the power consumed by the compressor, and the engine volumetric efficiency. Therefore, non-adiabatic turbocharger performance can restrict the engine charging process and hence engine performance. The prese...

  8. Novel Method for Measuring the Heat Collection Rate and Heat Loss Coefficient of Water-in-Glass Evacuated Tube Solar Water Heaters Based on Artificial Neural Networks and Support Vector Machine

    Directory of Open Access Journals (Sweden)

    Zhijian Liu

    2015-08-01

    Full Text Available The determinations of heat collection rate and heat loss coefficient are crucial for the evaluation of in service water-in-glass evacuated tube solar water heaters. However, the direct determination requires complex detection devices and a series of standard experiments, which also wastes too much time and manpower. To address this problem, we propose machine learning models including artificial neural networks (ANNs and support vector machines (SVM to predict the heat collection rate and heat loss coefficient without a direct determination. Parameters that can be easily obtained by “portable test instruments” were set as independent variables, including tube length, number of tubes, tube center distance, heat water mass in tank, collector area, final temperature and angle between tubes and ground, while the heat collection rate and heat loss coefficient determined by the detection device were set as dependent variables respectively. Nine hundred fifteen samples from in-service water-in-glass evacuated tube solar water heaters were used for training and testing the models. Results show that the multilayer feed-forward neural network (MLFN with 3 nodes is the best model for the prediction of heat collection rate and the general regression neural network (GRNN is the best model for the prediction of heat loss coefficient due to their low root mean square (RMS errors, short training times, and high prediction accuracies (under the tolerances of 30%, 20%, and 10%, respectively.

  9. Measurement accuracy of heart rate and respiratory rate during graded exercise and sustained exercise in the heat using the Zephyr BioHarness.

    Science.gov (United States)

    Kim, J-H; Roberge, R; Powell, J B; Shafer, A B; Jon Williams, W

    2013-06-01

    The Zephyr BioHarness was tested to determine the accuracy of heart rate (HR) and respiratory rate (RR) measurements during 2 exercise protocols in conjunction with either a laboratory metabolic cart (Vmax) or a previously validated portable metabolic system (K4b2). In one protocol, HR and RR were measured using the BioHarness and Vmax during a graded exercise up to V˙O2max (n=12). In another protocol, HR and RR were measured using the BH and K4b2 during sustained exercise (30% and 50% V˙O2max for 20 min each) in a hot environment (30 °C, 50% relative humidity) (n=6). During the graded exercise, HR but not RR, obtained from the BioHarness was higher compared to the Vmax at baseline and 30% V˙O2max (pexercise in the heat, there were no significant differences between the BioHarness and K4b2 system. Correlation coefficients between the methods were low for HR but moderately to highly correlated (0.49-0.99) for RR. In conclusion, the BioHarness is comparable to Vmax and K4b2 over a wide range of V˙O2 during graded exercise and sustained exercise in the heat.

  10. Self-heating probe instrument and method for measuring high temperature melting volume change rate of material

    Science.gov (United States)

    Wang, Junwei; Wang, Zhiping; Lu, Yang; Cheng, Bo

    2013-03-01

    The castings defects are affected by the melting volume change rate of material. The change rate has an important effect on running safety of the high temperature thermal storage chamber, too. But the characteristics of existing measuring installations are complex structure, troublesome operation and low precision. In order to measure the melting volume change rate of material accurately and conveniently, a self-designed measuring instrument, self-heating probe instrument, and measuring method are described. Temperature in heating cavity is controlled by PID temperature controller; melting volume change rate υ and molten density are calculated based on the melt volume which is measured by the instrument. Positive and negative υ represent expansion and shrinkage of the sample volume after melting, respectively. Taking eutectic LiF+CaF2 for example, its melting volume change rate and melting density at 1 123 K are -20.6% and 2 651 kg·m-3 measured by this instrument, which is only 0.71% smaller than literature value. Density and melting volume change rate of industry pure aluminum at 973 K and analysis pure NaCl at 1 123 K are detected by the instrument too. The measure results are agreed with report values. Measuring error sources are analyzed and several improving measures are proposed. In theory, the measuring errors of the change rate and molten density which are measured by the self-designed instrument is nearly 1/20-1/50 of that measured by the refitted mandril thermal expansion instrument. The self-designed instrument and method have the advantages of simple structure, being easy to operate, extensive applicability for material, relatively high accuracy, and most importantly, temperature and sample vapor pressure have little effect on the measurement accuracy. The presented instrument and method solve the problems of complicated structure and procedures, and large measuring errors for the samples with high vapor pressure by existing installations.

  11. Influence of heat and shear induced protein aggregation on the in vitro digestion rate of whey proteins.

    Science.gov (United States)

    Singh, Tanoj K; Øiseth, Sofia K; Lundin, Leif; Day, Li

    2014-11-01

    Protein intake is essential for growth and repair of body cells, the normal functioning of muscles, and health related immune functions. Most food proteins are consumed after undergoing various degrees of processing. Changes in protein structure and assembly as a result of processing impact the digestibility of proteins. Research in understanding to what extent the protein structure impacts the rate of proteolysis under human physiological conditions has gained considerable interest. In this work, four whey protein gels were prepared using heat processing at two different pH values, 6.8 and 4.6, with and without applied shear. The gels showed different protein network microstructures due to heat induced unfolding (at pH 6.8) or lack of unfolding, thus resulting in fine stranded protein networks. When shear was applied during heating, particulate protein networks were formed. The differences in the gel microstructures resulted in considerable differences in their rheological properties. An in vitro gastric and intestinal model was used to investigate the resulting effects of these different gel structures on whey protein digestion. In addition, the rate of digestion was monitored by taking samples at various time points throughout the in vitro digestion process. The peptides in the digesta were profiled using SDS-polyacrylamide gel electrophoresis, reversed-phase-HPLC and LC-MS. Under simulated gastric conditions, whey proteins in structured gels were hydrolysed faster than native proteins in solution. The rate of peptides released during in vitro digestion differed depending on the structure of the gels and extent of protein aggregation. The outcomes of this work highlighted that changes in the network structure of the protein can influence the rate and pattern of its proteolysis under gastrointestinal conditions. Such knowledge could assist the food industry in designing novel food formulations to control the digestion kinetics and the release of biologically

  12. Influence of body mass loss on changes in heart rate during exercise in the heat: a systematic review.

    Science.gov (United States)

    Adams, William M; Ferraro, Elizabeth M; Huggins, Robert A; Casa, Douglas J

    2014-08-01

    The purpose of this review was to compare the changes in heart rate (HR) for every 1% change in body mass loss (ΔBML) in individuals while exercising in the heat. PubMed, SPORTDiscus, ERIC, CINAHL, and Scopus were searched from the earliest entry to February 2013 using the search terms dehydration, heart rate, and exercise in various combinations. Original research articles that met the following criteria were included: (a) valid measure of HR, (b) exercise in the heat (>26.5° C [79.7 °F]), (c) the level of dehydration reached at least 2%, (d) a between-group comparison (a euhydrated group or a graded dehydration protocol) was evident, and (e) for rehydration protocols, only oral rehydration was considered for inclusion. Twenty articles were included in the final analysis. Mean values and SDs for HR and percentage of body mass loss immediately after exercise were used for this review. The mean change in HR for every 1% ΔBML was 3 b·min-1. In trials where subjects arrived euhydrated and hypohydrated, the mean change in HR for every 1% ΔBML was 3 and 3 b·min-1, respectively. Fixed intensity and variable intensity trials exhibited a mean HR change of 4 and 1 b·min-1, respectively. Exercising in the heat while hypohydrated (≥2%) resulted in an increased HR after exercise. This increase in HR for every 1% ΔBML exacerbates cardiovascular strain in exercising individuals, thus causing decrements in performance. It should be encouraged that individuals should maintain an adequate level of hydration to maximize performance, especially in the heat.

  13. VOLUMETRIC MASS TRANSFER COEFFICIENT BETWEEN SLAG AND METAL IN COMBINED BLOWING CONVERTER

    Institute of Scientific and Technical Information of China (English)

    Z.H. Wu; Z.S. Zou; W. Wu

    2005-01-01

    The effects of operation parameters of combined blowing converter on the volumetric mass transfer coefficient between slag and steel are studied with a cold model with water simulating steel, oil simulating slag and benzoic acid as the transferred substance between water and oil. The results show that, with lance level of 2.Im and the top blowing rate of 25000Nm3/h, the volumetric mass transfer coefficient changes most significantly when the bottom blowing rate ranges from 384 to 540Nm3/h. The volumetric mass transfer coefficient reaches its maximum when the lance level is 2. lm, the top blowing rates is 30000Nm3/h, and the bottom blowing rate is 384Nrr3/h with tuyeres located symmetrically at 0.66D of the converter bottom.

  14. On the determination of the activation energy of a thermoluminescence peak by the two-heating-rates method

    Energy Technology Data Exchange (ETDEWEB)

    Gartia, R.K.; Ingotombi, S.; Singh, Th.S.C.; Mazumdar, P.S. (Manipur Univ. (India). Dept. of Physics)

    1991-01-14

    In this paper precise estimation of the systematic error involved in the determination of the activation energy of a non-first-order thermoluminescence (TL) peak by using the two-heating-rates method (which is strictly valid for a first-order peak) has been made. A new method analogous to this method is proposed, which involves both the peak temperature and peak intensity. The systematic errors involved in both these methods are found to be within the experimental error which one generally encounters in the analysis of TL. The applicability of these findings has been tested by considering a second-order TL peak of limestone. (author).

  15. Influence of heating rate on the temperature of the (alpha+beta)-beta transformation of titanium alloys

    Energy Technology Data Exchange (ETDEWEB)

    Gridnev, V.N.; Ivasishin, O.M.; Markovskii, P.E.

    1985-07-01

    Results of a systematic experimental study of the effect of the heating rate, composition, and structure on the temperature of the (alpha+beta)-beta transformation in titanium alloys VT6, VT14, VT3-1, VT23, and VT22 are presented. It is shown that the transformation temperature of the alloys increases proportionally to the coefficient k-beta, which characterizes the alloy content, and to the size of the alpha-phase grains in the original structure. All other conditions being equal, the transformation is completed sooner in alloys with a spheroidal structure. 8 references.

  16. Optimization of the RF cavity heat load and trip rates for CEBAF at 12 GeV

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, He [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Roblin, Yves R. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Freyberger, Arne P. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Krafft, Geoffrey A. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Terzic, Balsa P. [Old Dominion Univ., Norfolk, VA (United States)

    2017-05-01

    The Continuous Electron Beam Accelerator Facility at JLab has 200 RF cavities in the north linac and the south linac respectively after the 12 GeV upgrade. The purpose of this work is to simultaneously optimize the heat load and the trip rate for the cavities and to reconstruct the pareto-optimal front in a timely manner when some of the cavities are turned down. By choosing an efficient optimizer and strategically creating the initial gradients, the pareto-optimal front for no more than 15 cavities down can be re-established within 20 seconds.

  17. Effect of high heating and cooling rate on interface of diffusion bonded gray cast iron to medium carbon steel

    Energy Technology Data Exchange (ETDEWEB)

    Kurt, B. [Firat University, Technical Education Faculty, Metal Department, 23119 Elazig (Turkey); Orhan, N. [Firat University, Technical Education Faculty, Metal Department, 23119 Elazig (Turkey)]. E-mail: norhan@firat.edu.tr; Hascalik, A. [Firat University, Technical Education Faculty, Department of Manufacturing, Elazig (Turkey)

    2007-07-01

    In the present study, a gray cast iron and a medium carbon steel couple were diffusion bonded at the temperatures of 850, 900, 950 and 1000 deg. C under a pressure of 8 MPa for 30 min, and the effects of temperature and high heating and cooling rate on interface formations and microstructure were investigated. After diffusion bonding, scanning electron microscopy, shear test measurements and microhardness measurement of interface region were made. The microstructure at the inside of medium carbon steel of bonded couple consisted of martensite. As a result, from the microstructural observations, a good bonding along the interface of the bonded couples and the interface is free from voids and microcracks.

  18. Modification of atomic physics rates due to nonlocal electron parallel heat transport in divertor plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Allais, F. [INRS-Energie, Materiaux et Telecommunications, 1650 boul. Lionel Boulet, Varennes, Quebec, J3X 1S2 (Canada); Matte, J.P. [INRS-Energie, Materiaux et Telecommunications, 1650 boul. Lionel Boulet, Varennes, Quebec, J3X 1S2 (Canada)]. E-mail: matte@inrs-emt.uquebec.ca; Alouani-Bibi, F. [INRS-Energie, Materiaux et Telecommunications, 1650 boul. Lionel Boulet, Varennes, Quebec, J3X 1S2 (Canada); Kim, C.G. [INRS-Energie, Materiaux et Telecommunications, 1650 boul. Lionel Boulet, Varennes, Quebec, J3X 1S2 (Canada); Stotler, D.P. [Princeton Plasma Physics Laboratory, Princeton, NJ (United States); Rognlien, T.D. [Lawrence Livermore National Laboratory, Livermore, CA (United States)

    2005-03-01

    The effect of steep temperature gradients on the rate of ionization of atomic hydrogen is studied numerically with the electron kinetic code 'FPI' [Phys. Rev. Lett. 72 (1994) 1208]. A set of cross sections ['Atomic and Plasma-Material Interaction data for fusion'. Supplement to the journal Nucl. Fusion 4 (1993)] has been used which gives the same rates of radiation, ionization and recombination as in the well known edge modeling codes 'UEDGE' and 'DEGAS' for Maxwellian electron energy distribution functions. For this purpose, 30 energy levels are included in the computation, as stepwise ionization is dominant. The enhancement of the ionization rate by non-Maxwellian effects in the colder part of the plasma is significant.

  19. Disentangling effects of potential shape in the fission rate of heated nuclei

    Science.gov (United States)

    Gontchar, I. I.; Chushnyakova, M. V.; Aktaev, N. E.; Litnevsky, A. L.; Pavlova, E. G.

    2010-12-01

    We have compared the results of dynamical modeling of the fission process with predictions of the Kramers formulas. For the case of large dissipation, there are two of them: the integral rate RI and its approximation RO. As the ratio of the fission barrier height Bf to the temperature T reaches 4, any analytical rate is expected to agree with the dynamical quasistationary rate RD within 2%. The latter has been obtained using numerical modeling with six different potentials. It has been found that the difference between RO and RD sometimes exceeds 20%. The features of the potentials used that are responsible for this disagreement are identified and studied. It is demonstrated that it is RI, not RO, that meets this expectation regardless of the potential used.

  20. Theoretical prediction of the effect of heat transfer parameters on cooling rates of liquid-filled plastic straws used for cryopreservation of spermatozoa.

    Science.gov (United States)

    Sansinen, M; Santos, M V; Zaritzky, N; Baez, R; Chirife, J

    2010-01-01

    Heat transfer plays a key role in cryopreservation of liquid semen in plastic straws. The effect of several parameters on the cooling rate of a liquid-filled polypropylene straw when plunged into liquid nitrogen was investigated using a theoretical model. The geometry of the straw containing the liquid was assimilated as two concentric finite cylinders of different materials: the fluid and the straw; the unsteady-state heat conduction equation for concentric cylinders was numerically solved. Parameters studied include external (convection) heat transfer coefficient (h), the thermal properties of straw manufacturing material and wall thickness. It was concluded that the single most important parameter affecting the cooling rate of a liquid column contained in a straw is the external heat transfer coefficient in LN2. Consequently, in order to attain maximum cooling rates, conditions have to be designed to obtain the highest possible heat transfer coefficient when the plastic straw is plunged in liquid nitrogen.

  1. Semi-automated volumetric analysis of lymph node metastases during follow-up--initial results.

    Science.gov (United States)

    Fabel, Michael; Bolte, H; von Tengg-Kobligk, H; Bornemann, L; Dicken, V; Delorme, S; Kauczor, H-U; Heller, M; Biederer, J

    2011-04-01

    Quantification of tumour burden in oncology requires accurate and reproducible evaluation. The current standard is RECIST measurement with its inherent disadvantages. Volumetric analysis is an alternative for therapy monitoring. The aim of this study was to evaluate the feasibility of volumetric analysis of lymph node metastases using a software prototype in a follow-up setting. MSCT was performed in 50 patients covering the chest, abdomen and pelvis. A total of 174 suspicious lymph nodes were evaluated by two radiologists regarding short axis diameters and volumetric analysis using semi-automated software. Quality of segmentation, time, maximum diameter and volume were documented. Variability of the derived change rates was computed as the standard deviation of the difference of the obtained respective change rates. The software performance provides robust volumetric analysis. Quality of segmentation was rated acceptable to excellent in 76-79% by each reader. Mean time spent per lesion was 38 s. The variability of change in effective diameters was 10.6%; for change rates of RECIST maximum diameter variability was 27.5%. Semi-automated volumetric analysis allows fast and convenient segmentation of most lymph node metastases. Compared with RECIST the inter-observer-variability in baseline and follow-up is reduced. This should principally allow subtle changes to be subclassified within the RECIST stable range as minor response [-15% to +10%].

  2. Treatment planning for volumetric modulated arc therapy

    Energy Technology Data Exchange (ETDEWEB)

    Bedford, James L. [Joint Department of Physics, Institute of Cancer Research and The Royal Marsden NHS Foundation Trust, Downs Road, Sutton, Surrey SM2 5PT (United Kingdom)

    2009-11-15

    Purpose: Volumetric modulated arc therapy (VMAT) is a specific type of intensity-modulated radiation therapy (IMRT) in which the gantry speed, multileaf collimator (MLC) leaf position, and dose rate vary continuously during delivery. A treatment planning system for VMAT is presented. Methods: Arc control points are created uniformly throughout one or more arcs. An iterative least-squares algorithm is used to generate a fluence profile at every control point. The control points are then grouped and all of the control points in a given group are used to approximate the fluence profiles. A direct-aperture optimization is then used to improve the solution, taking into account the allowed range of leaf motion of the MLC. Dose is calculated using a fast convolution algorithm and the motion between control points is approximated by 100 interpolated dose calculation points. The method has been applied to five cases, consisting of lung, rectum, prostate and seminal vesicles, prostate and pelvic lymph nodes, and head and neck. The resulting plans have been compared with segmental (step-and-shoot) IMRT and delivered and verified on an Elekta Synergy to ensure practicality. Results: For the lung, prostate and seminal vesicles, and rectum cases, VMAT provides a plan of similar quality to segmental IMRT but with faster delivery by up to a factor of 4. For the prostate and pelvic nodes and head-and-neck cases, the critical structure doses are reduced with VMAT, both of these cases having a longer delivery time than IMRT. The plans in general verify successfully, although the agreement between planned and measured doses is not very close for the more complex cases, particularly the head-and-neck case. Conclusions: Depending upon the emphasis in the treatment planning, VMAT provides treatment plans which are higher in quality and/or faster to deliver than IMRT. The scheme described has been successfully introduced into clinical use.

  3. Numerical investigation of entropy generation in microchannels heat sink with different shapes

    Science.gov (United States)

    Alfaryjat, A. A.; Stanciu, D.; Dobrovicescu, A.; Badescu, V.; Aldhaidhawi, M.

    2016-08-01

    Entropy generation of 3D cross sections circular, square, and hexagon shapes microchannel heat sinks (MCHS) were numerically performed. The governing equations (continuity, momentum and energy) along with the boundary conditions and the study state conjugate heat transfer problem were solved using the finite volume method (FVM). The Reynolds number in the range of 100 to 1600 and heat flux of 125, 150, 175 and 200 kW/m2 were covered in this study. The overall entropy generation rate and entropy generation number are obtained by integrating the volumetric rate components over the entire heat sink. The results indicated that entropy generation decreases with increases of the Reynolds number. Decreasing the heat flux led to decreasing entropy generation. The square microchannel heat sink has the lowest entropy generation and entropy generation number

  4. Influence of quench and heating rates on the ageing response of an Al-Zn-Mg-(Zr) alloy

    Energy Technology Data Exchange (ETDEWEB)

    Deschamps, A.; Brechet, Y. [Ecole Nationale Superieure d`Electrochimie et d`Electrometallurgie, 38 - Saint-Martin-d`Heres (France)

    1998-08-15

    The influence of the quench rate on the microstructure and the ageing response of a Zr-containing Al-Zn-Mg alloy was investigated. It is shown that Al{sub 3}Zr dispersoids are efficient nuclei for precipitation of coarse, equilibrium {eta} precipitates during the quench. Dispersoids are heterogeneously distributed in bands, resulting in bands of quenched-induced precipitates after a slow quench. The ageing response after a slow quench is characterized by various levels of heterogeneities resulting in a `composite` material. On a microscopic scale, quench-induced {eta} precipitates are surrounded by a precipitate-free zone. On a mesoscopic scale, the material is separated in unperturbed regions and regions of high density of coarse precipitates and low density of hardening precipitates. Finally, a slow quench makes the material more sensitive to the heating rate to the ageing temperature, due to slower GP zone precipitation during natural ageing because of annihilation of vacancies during quenching. (orig.) 21 refs.

  5. Aerodynamic pressure and heating-rate distributions in tile gaps around chine regions with pressure gradients at a Mach number of 6.6

    Science.gov (United States)

    Hunt, L. Roane; Notestine, Kristopher K.

    1990-06-01

    Surface and gap pressures and heating-rate distributions were obtained for simulated Thermal Protection System (TPS) tile arrays on the curved surface test apparatus of the Langley 8-Foot High Temperature Tunnel at Mach 6.6. The results indicated that the chine gap pressures varied inversely with gap width because larger gap widths allowed greater venting from the gap to the lower model side pressures. Lower gap pressures caused greater flow ingress from the surface and increased gap heating. Generally, gap heating was greater in the longitudinal gaps than in the circumferential gaps. Gap heating decreased with increasing gap depth. Circumferential gap heating at the mid-depth was generally less than about 10 percent of the external surface value. Gap heating was most severe at local T-gap junctions and tile-to-tile forward-facing steps that caused the greatest heating from flow impingement. The use of flow stoppers at discrete locations reduced heating from flow impingement. The use of flow stoppers at discrete locations reduced heating in most gaps but increased heating in others. Limited use of flow stoppers or gap filler in longitudinal gaps could reduce gap heating in open circumferential gaps in regions of high surface pressure gradients.

  6. Effects of viscous heating and wall-fluid interaction energy on rate-dependent slip behavior of simple fluids

    Science.gov (United States)

    Bao, Luyao; Priezjev, Nikolai V.; Hu, Haibao; Luo, Kai

    2017-09-01

    Molecular dynamics simulations are used to investigate the rate and temperature dependence of the slip length in thin liquid films confined by smooth, thermal substrates. In our setup, the heat generated in a force-driven flow is removed by the thermostat applied on several wall layers away from liquid-solid interfaces. We found that for both high and low wall-fluid interaction (WFI) energies, the temperature of the fluid phase rises significantly as the shear rate increases. Surprisingly, with increasing shear rate, the slip length approaches a constant value from above for high WFI energies and from below for low WFI energies. The two distinct trends of the rate-dependent slip length are rationalized by examining S ( G1) , the height of the main peak of the in-plane structure factor of the first fluid layer (FFL) together with DWF, which is the average distance between the wall and FFL. The results of numerical simulations demonstrate that reduced values of the structure factor, S ( G1) , correlate with the enhanced slip, while smaller distances DWF indicate that fluid atoms penetrate deeper into the surface potential leading to larger friction and smaller slip. Interestingly, at the lowest WFI energy, the combined effect of the increase of S ( G1) and decrease of DWF with increasing shear rate results in a dramatic reduction of the slip length.

  7. Multiplatform analysis of the radiative effects and heating rates for an intense dust storm on 21 June 2007

    Science.gov (United States)

    Naeger, Aaron R.; Christopher, Sundar A.; Johnson, Ben T.

    2013-08-01

    Dust radiative effects and atmospheric heating rates are investigated for a Saharan dust storm on 21 June 2007 using a combination of multiple satellite data sets and ground and aircraft observations as input into a delta-four stream radiative transfer model (RTM). This combines the strengths of the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations and CloudSat satellites and in situ aircraft data to characterize the vertical structure of the dust layers (5 km in height with optical depths between 1.5 and 2.0) and underlying low-level water clouds. These observations were used, along with Aerosol Robotic Network retrievals of aerosol optical properties, as input to the RTM to assess the surface, atmosphere, and top of atmosphere (TOA) shortwave aerosol radiative effects (SWAREs). Our results show that the dust TOA SWARE per unit aerosol optical depth was -56 W m-2 in cloud-free conditions over ocean and +74 W m-2 where the dust overlay low-level clouds, and show heating rates greater than 10 K/d. Additional case studies also confirm the results of the 21 June case. This study shows the importance of identifying clouds beneath dust as they can have a significant impact on the radiative effects of dust, and hence assessments of the role of dust aerosol on the energy budget and climate.

  8. A stock-flow consistent input-output model with applications to energy price shocks, interest rates, and heat emissions

    Science.gov (United States)

    Berg, Matthew; Hartley, Brian; Richters, Oliver

    2015-01-01

    By synthesizing stock-flow consistent models, input-output models, and aspects of ecological macroeconomics, a method is developed to simultaneously model monetary flows through the financial system, flows of produced goods and services through the real economy, and flows of physical materials through the natural environment. This paper highlights the linkages between the physical environment and the economic system by emphasizing the role of the energy industry. A conceptual model is developed in general form with an arbitrary number of sectors, while emphasizing connections with the agent-based, econophysics, and complexity economics literature. First, we use the model to challenge claims that 0% interest rates are a necessary condition for a stationary economy and conduct a stability analysis within the parameter space of interest rates and consumption parameters of an economy in stock-flow equilibrium. Second, we analyze the role of energy price shocks in contributing to recessions, incorporating several propagation and amplification mechanisms. Third, implied heat emissions from energy conversion and the effect of anthropogenic heat flux on climate change are considered in light of a minimal single-layer atmosphere climate model, although the model is only implicitly, not explicitly, linked to the economic model.

  9. Heating-Rate-Triggered Carbon-Nanotube-based 3-Dimensional Conducting Networks for a Highly Sensitive Noncontact Sensing Device

    KAUST Repository

    Tai, Yanlong

    2016-01-28

    Recently, flexible and transparent conductive films (TCFs) are drawing more attention for their central role in future applications of flexible electronics. Here, we report the controllable fabrication of TCFs for moisture-sensing applications based on heating-rate-triggered, 3-dimensional porous conducting networks through drop casting lithography of single-walled carbon nanotube (SWCNT)/poly(3,4-ethylenedioxythiophene)-polystyrene sulfonate (PEDOT:PSS) ink. How ink formula and baking conditions influence the self-assembled microstructure of the TCFs is discussed. The sensor presents high-performance properties, including a reasonable sheet resistance (2.1 kohm/sq), a high visible-range transmittance (>69%, PET = 90%), and good stability when subjected to cyclic loading (>1000 cycles, better than indium tin oxide film) during processing, when formulation parameters are well optimized (weight ratio of SWCNT to PEDOT:PSS: 1:0.5, SWCNT concentration: 0.3 mg/ml, and heating rate: 36 °C/minute). Moreover, the benefits of these kinds of TCFs were verified through a fully transparent, highly sensitive, rapid response, noncontact moisture-sensing device (5 × 5 sensing pixels).

  10. Influence of substrate heating on excited state generation rates and lifetime in organic solar cells studied by photoinduced absorption spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Ziehlke, Hannah; Koerner, Christian; Leo, Karl; Riede, Moritz [IAPP, TU Dresden (Germany); Fitzner, Roland; Reinold, Egon; Baeuerle, Peter [Institut fuer Organische Chemie II und Neue Materialien, Univ. Ulm (Germany)

    2011-07-01

    The performance of organic solar cells crucially depends on the separation of photogenerated excitons into free charge carriers. The dissociation process is sensitively influenced by the nanomorphology of donor (D) and acceptor (A) phases in the photoactive blend layer. Closed percolation paths have to be present such that the created charges are able to leave the blend layer, but also the crystallinity of the D- and the A-phase influence exciton dissociation on a molecular scale. Substrate heating during the vacuum deposition of the active layer is a method to influence the thin film morphology that can lead to improved device performance. We here characterize dicyanovinyl capped quinquethiophenes (D) deposited on substrates at different temperatures (30 and 80 C). Photoinduced absorption spectroscopy (PIA) is used to determine excited state lifetimes and generation rates.We find that efficient charge separation occurs in blends with C{sub 60} (A) and identify the observed excited states as donor cations and triplet excitons. Heating the substrate results in an increased lifetime of the donor cation on the one hand and a decrease in the generation rate of cations on the other hand. The PIA results are complemented by solar cell devices as well as morphological studies.

  11. Spin Dephasing as a Probe of Mode Temperature, Motional State Distributions, and Heating Rates in a 2D Ion Crystal

    CERN Document Server

    Sawyer, Brian C; Bollinger, John J

    2014-01-01

    We employ spin-dependent optical dipole forces to characterize the transverse center-of-mass (COM) motional mode of a two-dimensional Wigner crystal of hundreds of $^9$Be$^+$. By comparing the measured spin dephasing produced by the spin-dependent force with the predictions of a semiclassical dephasing model, we obtain absolute mode temperatures in excellent agreement with both the Doppler laser cooling limit and measurements obtained from a previously published technique (B. C. Sawyer et al. Phys. Rev. Lett. \\textbf{108}, 213003 (2012)). Furthermore, the structure of the dephasing histograms allows for discrimination between initial thermal and coherent states of motion. We also apply the techniques discussed here to measure, for the first time, the ambient heating rate of the COM mode of a 2D Coulomb crystal in a Penning trap. This measurement places an upper limit on the anomalous single-ion heating rate due to electric field noise from the trap electrode surfaces of $\\frac{d\\bar{n}}{dt}\\sim 5$ s$^{-1}$ fo...

  12. Effects of heating and cooling rate on transformation behaviors in weld heat affected zone of low carbon steel; Teitanso koban no yosetsu netsu eikyobu no hentai kyodo ni oyobosu kanetsu reikyaku sokudo no eikyo

    Energy Technology Data Exchange (ETDEWEB)

    Kanetsuki, Y.; Katsumata, M. [Kobe Steel, Ltd., Kobe (Japan)

    1998-01-25

    Discussions were given on effects of welding heat cycles on transformation behaviors in a weld heat affected zone (HAZ). Test pieces are low-carbon fine ferrite pearlite organization steel sheets, which have been treated with a thermomechanical control process (TMCP). The heat cycling was experimented at a maximum temperature of 1350 degC by using a high-frequency heating coil, heating rates from 0.15 to 200 degC/s, cooling rates from 10 to 80 degC/s at an elevated temperature region (higher than 900 degC), and transformation regions (lower than 900 degC) from 0.5 to 6 degC. A transformation curve in actual welding heat cycling was interpreted from these results. Shear-type inverse transformation (from ferrite to austenite) occurs in a rate region corresponding to the heating rate realized during welding. Austenite containing internal stress and a lower structure formed by this inverse transformation accelerates transformation into grain boundary ferrite (GBF) and acerous ferrite (AF). On the other hand, slow cooling in the elevated temperature region releases the internal stress, restores the lower structure, and suppresses the GBF and AF transformation. The GBF tends to precipitate pearlite in adjacent regions and deteriorates the HAZ tenacity. 17 refs., 8 figs., 1 tab.

  13. Rate of evaporation from the free surface of a heated liquid

    Science.gov (United States)

    Örvös, M.; Szabó, V.; Poós, T.

    2016-11-01

    A method and an experimental setup are developed for determining the intensity of evaporation from the free surface of water. During the measurement, the ambient air velocity and the water temperature can be varied. The mass and temperature of water, as well as the temperature, pressure, and humidity of the ambient air are measured as functions of time. The evaporation rates are calculated from the measured and recorded data in the cases of natural and forced convection.

  14. Comparison of heat transfer in liquid and slush nitrogen by numerical simulation of cooling rates for French straws used for sperm cryopreservation.

    Science.gov (United States)

    Sansinena, M; Santos, M V; Zaritzky, N; Chirife, J

    2012-05-01

    Slush nitrogen (SN(2)) is a mixture of solid nitrogen and liquid nitrogen, with an average temperature of -207 °C. To investigate whether plunging a French plastic straw (commonly used for sperm cryopreservation) in SN(2) substantially increases cooling rates with respect to liquid nitrogen (LN(2)), a numerical simulation of the heat conduction equation with convective boundary condition was used to predict cooling rates. Calculations performed using heat transfer coefficients in the range of film boiling confirmed the main benefit of plunging a straw in slush over LN(2) did not arise from their temperature difference (-207 vs. -196 °C), but rather from an increase in the external heat transfer coefficient. Numerical simulations using high heat transfer (h) coefficients (assumed to prevail in SN(2)) suggested that plunging in SN(2) would increase cooling rates of French straw. This increase of cooling rates was attributed to a less or null film boiling responsible for low heat transfer coefficients in liquid nitrogen when the straw is placed in the solid-liquid mixture or slush. In addition, predicted cooling rates of French straws in SN(2) tended to level-off for high h values, suggesting heat transfer was dictated by heat conduction within the liquid filled plastic straw.

  15. Myowater dynamics and protein secondary structural changes as affected by heating rate in three pork qualities: a combined FT-IR microspectroscopic and 1H NMR relaxometry study.

    Science.gov (United States)

    Wu, Zhiyun; Bertram, Hanne Christine; Böcker, Ulrike; Ofstad, Ragni; Kohler, Achim

    2007-05-16

    The objective of this study was to investigate the influence of heating rate on myowater dynamics and protein secondary structures in three pork qualities by proton NMR T2 relaxation and Fourier transform infrared (FT-IR) microspectroscopy measurements. Two oven temperatures at 100 degrees C and 200 degrees C corresponding to slow and fast heating rates were applied on three pork qualities (DFD, PSE, and normal) to an internal center temperature of 65 degrees C. The fast heating induced a higher cooking loss, particularly for PSE meat. The water proton T21 distribution representing water entrapped within the myofibrillar network was influenced by heating rate and meat quality. Fast heating broadened the T21 distribution and decreased the relaxation times of the T21 peak position for three meat qualities. The changes in T21 relaxation times in meat can be interpreted in terms of chemical and diffusive exchange. FT-IR showed that fast heating caused a higher gain of random structures and aggregated beta-sheets at the expense of native alpha-helixes, and these changes dominate the fast-heating-induced broadening of T21 distribution and reduction in T21 times. Furthermore, of the three meat qualities, PSE meat had the broadest T21 distribution and the lowest T21 times for both heating rates, reflecting that the protein aggregation of PSE caused by heating is more extensive than those of DFD and normal, which is consistent with the IR data. The present study demonstrated that the changes in T2 relaxation times of water protons affected by heating rate and raw meat quality are well related to the protein secondary structural changes as probed by FT-IR microspectroscopy.

  16. Local thermal pressurization triggered by flash heating causes dramatic weakening in water-saturated gouges at subseismic slip rates

    Science.gov (United States)

    Yao, Lu; Ma, Shengli; Shimamoto, Toshihiko; Togo, Tetsuhiro; Chen, Jianye; Kitajima, Hiroko; Wang, Yu; He, Honglin

    2017-04-01

    High-velocity friction studies on water-saturated gouges in recent years have demonstrated that the wet gouges subjected to high-velocity shear tend to have smaller peak and steady-state friction, much shorter slip-weakening distance and lower fracture energy, as compared to the air-dry gouges. Thermal pressurization, compaction-induced pressurization, and flash heating were previously recognized to be the important weakening mechanisms in causing these behaviors. However, in spite of theoretical expectation, there is few evidence to support the occurrence of flash heating in wet gouges, mainly due to the superimposition of multiple weakening mechanisms especially for thermal pressurization. We devised friction experiments to study the role of flash heating in dynamic weakening of water-saturated gouges. In each experiment, we used a pressure vessel to impose a pore pressure of 2.0 MPa on the gouge layer sandwiched between porous ceramics blocks, and applied a long preslide of 1.0 m in displacement before starting the experiment at the target slip rate. By doing so we could (1) suppress rapid thermal pressurization in the bulk gouge layer by means of the designed drained condition and elevated temperature of phase transition of pore water; (2) suppress or even eliminate the pressurization effects due to compaction especially at the very beginning of the experiment. The experiments were performed on a granular gouge (mainly quartz, plagioclase, calcite and illite) and a clay-rich gouge (illite and chlorite ˜58 wt%), which were both collected from the Qingchuan fault of the Longmenshan fault system. For the granular gouge, the steady-state friction coefficients (μss) are 0.39-0.42 at slip rates (V ) of 100 μm/s-10 mm/s; however, at V ≥40 mm/s, the friction coefficients (μ) decrease suddenly at the onset of the slip. For instance, μ reduces by 0.29 within displacement of 0.05-0.08m at V =100 mm/s. For the clay-rich gouge, μss increases from 0.24 to 0.34 as V

  17. Process conditions and volumetric composition in composites

    DEFF Research Database (Denmark)

    Madsen, Bo

    2013-01-01

    The obtainable volumetric composition in composites is linked to the gravimetric composition, and it is influenced by the conditions of the manufacturing process. A model for the volumetric composition is presented, where the volume fractions of fibers, matrix and porosity are calculated as a fun...... is increased. Altogether, the model is demonstrated to be a valuable tool for a quantitative analysis of the effect of process conditions. Based on the presented findings and considerations, examples of future work are mentioned for the further improvement of the model.......The obtainable volumetric composition in composites is linked to the gravimetric composition, and it is influenced by the conditions of the manufacturing process. A model for the volumetric composition is presented, where the volume fractions of fibers, matrix and porosity are calculated...... as a function of the fiber weight fraction, and where parameters are included for the composite microstructure, and the fiber assembly compaction behavior. Based on experimental data of composites manufactured with different process conditions, together with model predictions, different types of process related...

  18. Indexing Volumetric Shapes with Matching and Packing.

    Science.gov (United States)

    Koes, David Ryan; Camacho, Carlos J

    2015-04-01

    We describe a novel algorithm for bulk-loading an index with high-dimensional data and apply it to the problem of volumetric shape matching. Our matching and packing algorithm is a general approach for packing data according to a similarity metric. First an approximate k-nearest neighbor graph is constructed using vantage-point initialization, an improvement to previous work that decreases construction time while improving the quality of approximation. Then graph matching is iteratively performed to pack related items closely together. The end result is a dense index with good performance. We define a new query specification for shape matching that uses minimum and maximum shape constraints to explicitly specify the spatial requirements of the desired shape. This specification provides a natural language for performing volumetric shape matching and is readily supported by the geometry-based similarity search (GSS) tree, an indexing structure that maintains explicit representations of volumetric shape. We describe our implementation of a GSS tree for volumetric shape matching and provide a comprehensive evaluation of parameter sensitivity, performance, and scalability. Compared to previous bulk-loading algorithms, we find that matching and packing can construct a GSS-tree index in the same amount of time that is denser, flatter, and better performing, with an observed average performance improvement of 2X.

  19. Effect of heating rate on mechanical property, microstructure and texture evolution of Al–Mg–Si–Cu alloy during solution treatment

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Xiaofeng; Guo, Mingxing, E-mail: mingxingguo@skl.ustb.edu.cn; Cao, Lingyong; Luo, Jinru; Zhang, Jishan; Zhuang, Linzhong

    2015-01-05

    The effect of heating rate on the mechanical properties, microstructure and texture of Al–Mg–Si–Cu alloy during solution treatment was investigated through tensile testing, scanning electron microscope, scanning transmission electron microscope, metallographic observation and EBSD measurement. The experimental results reveal that there are great differences in the mechanical properties, microstructures and textures after the solution treatment with two different heating rates. Compared with the alloy sheet solution treated with slow heating rate, the alloy sheet solution treated with rapid heating rate possesses weak mechanical property anisotropy and higher average r value. The equiaxed grain is the main recrystallization microstructure for the case of rapid heating rate, while the elongated grain appears in the case of slow heating rate. The texture components are also quite different in the two cases, Cube{sub ND} orientation is the main texture component for the former case, while the latter one includes Cube, R, Goss, P and Brass orientations. The relationship between r value, texture components and microstructure has also been established in this paper.

  20. Mathematical modeling of unsteady response of plate and fin heat exchanger to sudden change in liquid flow rate

    Directory of Open Access Journals (Sweden)

    Korzeń Anna

    2017-01-01

    The results of the numerical simulations of a heat exchanger using experimentally determined air and water-side heat transfer formulas for calculation of heat transfer coefficient were compared with the experimental data. Very good agreement of computation results (i.e. air and water temperature at the outlet of the heat exchanger with the experimental data was obtained.

  1. Rating of an air-to-air heat exchanger in practice; Untersuchung eines Luft-Luft-Waermetauschers unter Praxisbedingungen

    Energy Technology Data Exchange (ETDEWEB)

    Roesmann, Peter; Buescher, Wolfgang [Bonn Univ. (Germany). Abt. ' ' Verfahrenstechnik der Tierischen Erzeugung' '

    2010-07-01

    Barn ventilation is often associated with heat loss. This can be regulated by using appropriate heating technology during the cold season. Air-to-air heat exchanger can be used to recover some of the heat from outlet air. Thereby the system transfers some of the heat from the outlet air to incoming fresh air by heat exchange surfaces. For objective review the DLG has multiple tested this technology on test bed. Long term investigations in practice have taken place rarely. The Institute of Agricultural Engineering, University of Bonn, therefore has tested an recuperative heat exchanger in long term study which was installed in a piglet house. (orig.)

  2. The influence of flow rate on inter-nucleation site heat transport

    Directory of Open Access Journals (Sweden)

    Baltis Coen

    2014-01-01

    Full Text Available The main topic of this paper is the influence of vertically aligned nucleation sites on each other in upward flow boiling. A setup was constructed to facilitate vertical up-flow of deminiralized water under saturation conditions. The main test section is a glass channel with a set of vertically aligned bubble generators. Each bubble generator is operated independently, where power and wall temperature are registered and the vapour bubbles are visualized by a high-speed camera. During the experiments, the downstream bubble generator (BG1 power is kept constant, while the power fed to the upstream bubble generator (BG2 is incrementally increased. Two main trends have been identified. The first trend is dominated by added convection from one site to the other. Both bubble frequency and detachment diameter on BG1 increase with increased power fed to upstream BG2. This effect decreases with increasing inter-site distance and becomes more significant with increasing liquid flow rate. When vapor bubbles start nucleating from BG2, these vapor bubbles inhibit bubble nucleation BG1 and can even lead to deactivation of this nucleation site. This second trend is only weakly dependent on inter-site distance, since the inhibition originates from bubbles flowing past BG1 in close proximity.

  3. Single step full volumetric reconstruction optical coherence tomography utilizing compressive sensing

    Science.gov (United States)

    Chen, Luoyang; Liu, Jiansheng; cheng, Jiangtao; Liu, Haitao; Zhou, Hongwen

    2017-03-01

    3D optical coherence tomography imaging (OCT) combined with compressive sensing (CS) has been proved to be an attractive and effective tool in a variety of fields, such as medicine and biology. To achieve high quality imaging while using as less CS sampling rate as possible is the goal of this approach. Here we present an innovative single step fully 3D CS-OCT volumetric image recovery method, in which 3D OCT volumetric image of the object is compressively sampled via our proposed CS coding strategies in all three dimensions while its sparsity is simultaneously taken into consideration in every direction. The object can be directly recovered as the whole volume reconstruction via our advanced full 3D CS reconstruction algorithm. The numerical simulations of a human retina OCT volumetric image reconstruction by our method demonstrate a PSNR of as high as 38dB at a sampling rate of less than 10%.

  4. Impact of Heating Rate During Exposure of Laser Molten Parts on the Processing Window of PA12 Powder

    Science.gov (United States)

    Drummer, Dietmar; Drexler, Maximilian; Wudy, Katrin

    The additive component manufacturing by selective beam melting of thermoplastic polymer powders can be divided essentially into the following sub-processes: Powder coating, exposure and material consolidation. The mechanical and geometrical properties of a part produced by the selective melting of polymer powders depend toa large extent on these sub-processes. To increase process repeatability basic knowledge about the mutual interactions within the sub-process is of major interest. In the following article the exposure process is focused. Therefore the time dependent energy input into the powder bed is analyzed in its impact on the usable processing window of PA12powder. Thereby parameters like surface temperature, density and strength of molten layers as well as complex body specimens are quantified for varying exposure heating rates. Therefore methods of statistical design of experiments are used. Due to these investigations the derivation of new, the time dependent material behavior of polymers fitting processing strategies is possible.

  5. A critical appraisal of methods of various heating rates for the determination of the activation energy of a thermoluminescence peak

    Energy Technology Data Exchange (ETDEWEB)

    Singh, T.S.C.; Mazumdar, P.S.; Gartia, R.K. (Manipur Univ., Canchipur (India). Dept. of Physics)

    1990-05-14

    An attempt has been made to find out precisely the errors involved in the determination of the activation energy (E) of a thermoluminescence (TL) peak by using the different variants of method of various heating rates. It has been found that for all practical purposes two methods can be considered to be independent of the order of kinetics of the TL process. Finally, the applicability of our findings has been tested experimentally by considering a non-first-order TL peak. The results suggest that the theoretical errors in all the cases are less than the experimental ones and hence these methods can be safely used for all types of TL peaks irrespective of their order of kinetics. (author).

  6. Estimation of the dust production rate from the tungsten armour after repetitive ELM-like heat loads

    Science.gov (United States)

    Pestchanyi, S.; Garkusha, I.; Makhlaj, V.; Landman, I.

    2011-12-01

    Experimental simulations for the erosion rate of tungsten targets under ITER edge-localized mode (ELM)-like surface heat loads of 0.75 MJ m-2 causing surface melting and of 0.45 MJ m-2 without melting have been performed in the QSPA-Kh50 plasma accelerator. Analytical considerations allow us to conclude that for both energy deposition values the erosion mechanism is solid dust ejection during surface cracking under the action of thermo-stress. Tungsten influx into the ITER containment of NW~5×1018 W per medium size ELM of 0.75 MJ m-2 and 0.25 ms time duration has been estimated. The radiation cooling power of Prad=150-300 MW due to such influx of tungsten is intolerable: it should cool the ITER core to 1 keV within a few seconds.

  7. Normal and anomalous heating rate effects on thermoluminescence of Ce-doped ZnB2O4.

    Science.gov (United States)

    Dogan, Tamer; Yüksel, Mehmet; Akça, Sibel; Portakal, Ziyafer Gizem; Balci-Yegen, Sümeyra; Kucuk, Nil; Topaksu, Mustafa

    2017-10-01

    The effect of heating rate (HR) on thermoluminescence (TL) glow curves of 1%, 4%, and 10% Ce(3 +) doped ZnB2O4 phosphors was investigated in detail. The glow peaks are examined and, activation energy (E) and frequency factor (s) are determined by using various heating rate (VHR) method. In the obtained glow curves with nine different HRs between 2 and 10°C/s, it was observed that the TL intensities of the first peaks of all three samples and the second peak of 10% Ce(3 +) doped sample decrease with increasing HR. The decrease in TL intensity was investigated whether it may be due to the presence of thermal quenching or not. On the other hand, the second glow peaks of 1, 4% Ce(3 +) doped ZnB2O4 phosphors show an anomalous TL behavior, which the probability of the radiative processes increases due to recombination of free electrons, so the TL intensity increases with the HR. The graphs of full width at the half maximum (FWHM) versus HR were also plotted to evaluate the influence of HR on TL intensity. In this paper, we suggest that the non-localized Schön - Klasens model may give an explanation for the second peaks of 1, 4% Ce(3 +) doped ZnB2O4 phosphors showing an unexpected increase with the increasing HR. In addition, the calculated E values of all doped phosphors were found similar in the range of 0.47-0.53eV for peak 1 and 0.61-0.66eV for peak 2. However, s values of Ce(3 +) doped ZnB2O4 phosphors were found slightly different according to the dopant amount and the equation used. Furthermore, different amount of Ce(3 +) doped samples indicate the similar properties for the repeated cycles of 5Gy in the same irradiation conditions. Copyright © 2017 Elsevier Ltd. All rights reserved.

  8. A macroscale mixture theory analysis of deposition and sublimation rates during heat and mass transfer in dry snow

    Directory of Open Access Journals (Sweden)

    A. C. Hansen

    2015-09-01

    Full Text Available The microstructure of a dry alpine snowpack is a dynamic environment where microstructural evolution is driven by seasonal density profiles and weather conditions. Notably, temperature gradients on the order of 10–20 K m−1, or larger, are known to produce a faceted snow microstructure exhibiting little strength. However, while strong temperature gradients are widely accepted as the primary driver for kinetic growth, they do not fully account for the range of experimental observations. An additional factor influencing snow metamorphism is believed to be the rate of mass transfer at the macroscale. We develop a mixture theory capable of predicting macroscale deposition and/or sublimation in a snow cover under temperature gradient conditions. Temperature gradients and mass exchange are tracked over periods ranging from 1 to 10 days. Interesting heat and mass transfer behavior is observed near the ground, near the surface, as well as immediately above and below dense ice crusts. Information about deposition (condensation and sublimation rates may help explain snow metamorphism phenomena that cannot be accounted for by temperature gradients alone. The macroscale heat and mass transfer analysis requires accurate representations of the effective thermal conductivity and the effective mass diffusion coefficient for snow. We develop analytical models for these parameters based on first principles at the microscale. The expressions derived contain no empirical adjustments, and further, provide self consistent values for effective thermal conductivity and the effective diffusion coefficient for the limiting cases of air and solid ice. The predicted values for these macroscale material parameters are also in excellent agreement with numerical results based on microscale finite element analyses of representative volume elements generated from X-ray tomography.

  9. A macroscale mixture theory analysis of deposition and sublimation rates during heat and mass transfer in snow

    Directory of Open Access Journals (Sweden)

    A. C. Hansen

    2015-03-01

    Full Text Available The microstructure of a dry alpine snowpack is a dynamic environment where microstructural evolution is driven by seasonal density profiles and weather conditions. Notably, temperature gradients on the order of 10–20 K m−1, or larger, are known to produce a faceted snow microstructure exhibiting little strength. However, while strong temperature gradients are widely accepted as the primary driver for kinetic growth, they do not fully account for the range of experimental observations. An additional factor influencing snow metamorphism is believed to be the rate of mass transfer at the macroscale. We develop a mixture theory capable of predicting macroscale deposition and/or sublimation in a snow cover under temperature gradient conditions. Temperature gradients and mass exchange are tracked over periods ranging from 1 to 10 days. Interesting heat and mass transfer behavior is observed near the ground, near the surface, as well as immediately above and below dense ice crusts. Information about deposition (condensation and sublimation rates may help explain snow metamorphism phenomena that cannot be accounted for by temperature gradients alone. The macroscale heat and mass transfer analysis requires accurate representations of the thermal conductivity and the effective mass diffusion coefficient for snow. We develop analytical models for these parameters based on first principles at the microscale. The expressions derived contain no empirical adjustments, and further, provide self consistent values for thermal conductivity and the effective diffusion coefficient for the limiting cases of air and solid ice. The predicted values for these macroscale material parameters are also in excellent agreement with numerical results based on microscale finite element analyses of representative volume elements generated from X-ray tomography.

  10. Calculating clear-sky radiative heating rates using the Fu-Liou RTM with inputs from observed and reanalyzed profiles

    Science.gov (United States)

    Dolinar, E. K.; Dong, X.; Xi, B.

    2015-12-01

    One-dimensional radiative transfer models (RTM) are a common tool used for calculating atmospheric heating rates and radiative fluxes. In the forward sense, RTMs use known (or observed) quantities of the atmospheric state and surface characteristics to determine the appropriate surface and top-of-atmosphere (TOA) radiative fluxes. The NASA CERES science team uses the modified Fu-Liou RTM to calculate atmospheric heating rates and surface and TOA fluxes using the CERES observed TOA shortwave (SW) and longwave (LW) fluxes as constraints to derive global surface and TOA radiation budgets using a reanalyzed atmospheric state (e.g. temperature and various greenhouse gases) from the newly developed MERRA-2. However, closure studies have shown that using the reanalyzed state as input to the RTM introduces some disparity between the RTM calculated fluxes and surface observed ones. The purpose of this study is to generate a database of observed atmospheric state profiles, from satellite and ground-based sources, at several permanent Atmospheric Radiation Measurement (ARM) Program sites, including the Southern Great Plains (SGP), Northern Slope of Alaska (NSA) and Tropical Western Pacific Nauru (TWP-C2), and Eastern North Atlantic (ENA) permanent facilities. Since clouds are a major modulator of radiative transfer within the Earth's atmosphere, we will focus on the clear-sky conditions in this study, which will set up the baseline for our cloudy studies in the future. Clear-sky flux profiles are calculated using the Edition 4 NASA LaRC modified Fu-Liou RTM. The aforementioned atmospheric profiles generated in-house are used as input into the RTM, as well as from reanalyses. The calculated surface and TOA fluxes are compared with ARM surface measured and CERES satellite observed SW and LW fluxes, respectively. Clear-sky cases are identified by the ARM radar-lidar observations, as well as satellite observations, at the select ARM sites.

  11. Relationship of efficiency indices with performance, heart rate, oxygen consumption, blood parameters, and estimated heat production in Nellore steers.

    Science.gov (United States)

    Chaves, A S; Nascimento, M L; Tullio, R R; Rosa, A N; Alencar, M M; Lanna, D P

    2015-10-01

    The objective of this study was to examine the relationship of efficiency indices with performance, heart rate, oxygen consumption, blood parameters, and estimated heat production (EHP) in Nellore steers. Eighteen steers were individually lot-fed diets of 2.7 Mcal ME/kg DM for 84 d. Estimated heat production was determined using oxygen pulse (OP) methodology, in which heart rate (HR) was monitored for 4 consecutive days. Oxygen pulse was obtained by simultaneously measuring HR and oxygen consumption during a 10- to 15-min period. Efficiency traits studied were feed efficiency (G:F) and residual feed intake (RFI) obtained by regression of DMI in relation to ADG and midtest metabolic BW (RFI). Alternatively, RFI was also obtained based on equations reported by the NRC's to estimate individual requirement and DMI (RFI calculated by the NRC [1996] equation [RFI]). The slope of the regression equation and its significance was used to evaluate the effect of efficiency indices (RFI, RFI, or G:F) on the traits studied. A mixed model was used considering RFI, RFI, or G:F and pen type as fixed effects and initial age as a covariate. For HR and EHP variables, day was included as a random effect. There was no relationship between efficiency indices and back fat depth measured by ultrasound or daily HR and EHP ( > 0.05). Because G:F is obtained in relation to BW, the slope of G:F was positive and significant ( consumption per beat was not related to G:F; however, it was lower for RFI- and RFI-efficient steers, and consequently, oxygen volume (mL·min·kg) and OP (μL O·beat·kg) were also lower ( 0.05); however, G:F-efficient steers showed lower hematocrit and hemoglobin concentrations ( consumption and OP were detected, indicating that the OP methodology may be useful to predict growth efficiency.

  12. Geothermal flux and basal melt rate in the Dome C region inferred from radar reflectivity and heat modelling

    Directory of Open Access Journals (Sweden)

    O. Passalacqua

    2017-09-01

    Full Text Available Basal melt rate is the most important physical quantity to be evaluated when looking for an old-ice drilling site, and it depends to a great extent on the geothermal flux (GF, which is poorly known under the East Antarctic ice sheet. Given that wet bedrock has higher reflectivity than dry bedrock, the wetness of the ice–bed interface can be assessed using radar echoes from the bedrock. But, since basal conditions depend on heat transfer forced by climate but lagged by the thick ice, the basal ice may currently be frozen whereas in the past it was generally melting. For that reason, the risk of bias between present and past conditions has to be evaluated. The objective of this study is to assess which locations in the Dome C area could have been protected from basal melting at any time in the past, which requires evaluating GF. We used an inverse approach to retrieve GF from radar-inferred distribution of wet and dry beds. A 1-D heat model is run over the last 800 ka to constrain the value of GF by assessing a critical ice thickness, i.e. the minimum ice thickness that would allow the present local distribution of basal melting. A regional map of the GF was then inferred over a 80 km  ×  130 km area, with a N–S gradient and with values ranging from 48 to 60 mW m−2. The forward model was then emulated by a polynomial function to compute a time-averaged value of the spatially variable basal melt rate over the region. Three main subregions appear to be free of basal melting, two because of a thin overlying ice and one, north of Dome C, because of a low GF.

  13. Geothermal flux and basal melt rate in the Dome C region inferred from radar reflectivity and heat modelling

    Science.gov (United States)

    Passalacqua, Olivier; Ritz, Catherine; Parrenin, Frédéric; Urbini, Stefano; Frezzotti, Massimo

    2017-09-01

    Basal melt rate is the most important physical quantity to be evaluated when looking for an old-ice drilling site, and it depends to a great extent on the geothermal flux (GF), which is poorly known under the East Antarctic ice sheet. Given that wet bedrock has higher reflectivity than dry bedrock, the wetness of the ice-bed interface can be assessed using radar echoes from the bedrock. But, since basal conditions depend on heat transfer forced by climate but lagged by the thick ice, the basal ice may currently be frozen whereas in the past it was generally melting. For that reason, the risk of bias between present and past conditions has to be evaluated. The objective of this study is to assess which locations in the Dome C area could have been protected from basal melting at any time in the past, which requires evaluating GF. We used an inverse approach to retrieve GF from radar-inferred distribution of wet and dry beds. A 1-D heat model is run over the last 800 ka to constrain the value of GF by assessing a critical ice thickness, i.e. the minimum ice thickness that would allow the present local distribution of basal melting. A regional map of the GF was then inferred over a 80 km × 130 km area, with a N-S gradient and with values ranging from 48 to 60 mW m-2. The forward model was then emulated by a polynomial function to compute a time-averaged value of the spatially variable basal melt rate over the region. Three main subregions appear to be free of basal melting, two because of a thin overlying ice and one, north of Dome C, because of a low GF.

  14. The Effect of Cumulus Cloud Field Anisotropy on Domain-Averaged Solar Fluxes and Atmospheric Heating Rates

    Science.gov (United States)

    Hinkelman, Laura M.; Evans, K. Franklin; Clothiaux, Eugene E.; Ackerman, Thomas P.; Stackhouse, Paul W., Jr.

    2006-01-01

    Cumulus clouds can become tilted or elongated in the presence of wind shear. Nevertheless, most studies of the interaction of cumulus clouds and radiation have assumed these clouds to be isotropic. This paper describes an investigation of the effect of fair-weather cumulus cloud field anisotropy on domain-averaged solar fluxes and atmospheric heating rate profiles. A stochastic field generation algorithm was used to produce twenty three-dimensional liquid water content fields based on the statistical properties of cloud scenes from a large eddy simulation. Progressively greater degrees of x-z plane tilting and horizontal stretching were imposed on each of these scenes, so that an ensemble of scenes was produced for each level of distortion. The resulting scenes were used as input to a three-dimensional Monte Carlo radiative transfer model. Domain-average transmission, reflection, and absorption of broadband solar radiation were computed for each scene along with the average heating rate profile. Both tilt and horizontal stretching were found to significantly affect calculated fluxes, with the amount and sign of flux differences depending strongly on sun position relative to cloud distortion geometry. The mechanisms by which anisotropy interacts with solar fluxes were investigated by comparisons to independent pixel approximation and tilted independent pixel approximation computations for the same scenes. Cumulus anisotropy was found to most strongly impact solar radiative transfer by changing the effective cloud fraction, i.e., the cloud fraction when the field is projected on a surface perpendicular to the direction of the incident solar beam.

  15. Volumetric measurement of tank volume

    Science.gov (United States)

    Walter, Richard T. (Inventor); Vanbuskirk, Paul D. (Inventor); Weber, William F. (Inventor); Froebel, Richard C. (Inventor)

    1991-01-01

    A method is disclosed for determining the volume of compressible gas in a system including incompressible substances in a zero-gravity environment consisting of measuring the change in pressure (delta P) for a known volume change rate (delta V/delta t) in the polytrophic region between isothermal and adiabatic conditions. The measurements are utilized in an idealized formula for determining the change in isothermal pressure (delta P sub iso) for the gas. From the isothermal pressure change (delta iso) the gas volume is obtained. The method is also applicable to determination of gas volume by utilizing work (W) in the compression process. In a passive system, the relationship of specific densities can be obtained.

  16. Volumetric breast density affects performance of digital screening mammography.

    Science.gov (United States)

    Wanders, Johanna O P; Holland, Katharina; Veldhuis, Wouter B; Mann, Ritse M; Pijnappel, Ruud M; Peeters, Petra H M; van Gils, Carla H; Karssemeijer, Nico

    2017-02-01

    To determine to what extent automatically measured volumetric mammographic density influences screening performance when using digital mammography (DM). We collected a consecutive series of 111,898 DM examinations (2003-2011) from one screening unit of the Dutch biennial screening program (age 50-75 years). Volumetric mammographic density was automatically assessed using Volpara. We determined screening performance measures for four density categories comparable to the American College of Radiology (ACR) breast density categories. Of all the examinations, 21.6% were categorized as density category 1 ('almost entirely fatty') and 41.5, 28.9, and 8.0% as category 2-4 ('extremely dense'), respectively. We identified 667 screen-detected and 234 interval cancers. Interval cancer rates were 0.7, 1.9, 2.9, and 4.4‰ and false positive rates were 11.2, 15.1, 18.2, and 23.8‰ for categories 1-4, respectively (both p-trend density categories: 85.7, 77.6, 69.5, and 61.0% for categories 1-4, respectively (p-trend density, automatically measured on digital mammograms, impacts screening performance measures along the same patterns as established with ACR breast density categories. Since measuring breast density fully automatically has much higher reproducibility than visual assessment, this automatic method could help with implementing density-based supplemental screening.

  17. Numerical evaluation of an innovative cup layout for open volumetric solar air receivers

    Science.gov (United States)

    Cagnoli, Mattia; Savoldi, Laura; Zanino, Roberto; Zaversky, Fritz

    2016-05-01

    This paper proposes an innovative volumetric solar absorber design to be used in high-temperature air receivers of solar power tower plants. The innovative absorber, a so-called CPC-stacked-plate configuration, applies the well-known principle of a compound parabolic concentrator (CPC) for the first time in a volumetric solar receiver, heating air to high temperatures. The proposed absorber configuration is analyzed numerically, applying first the open-source ray-tracing software Tonatiuh in order to obtain the solar flux distribution on the absorber's surfaces. Next, a Computational Fluid Dynamic (CFD) analysis of a representative single channel of the innovative receiver is performed, using the commercial CFD software ANSYS Fluent. The solution of the conjugate heat transfer problem shows that the behavior of the new absorber concept is promising, however further optimization of the geometry will be necessary in order to exceed the performance of the classical absorber designs.

  18. Analysis of Tube Bank Heat Transfer In Downward Directed Foam Flow

    Directory of Open Access Journals (Sweden)

    Jonas Gylys

    2004-06-01

    Full Text Available Apparatus with the foam flow are suitable to use in different technologies like heat exchangers, food industry, chemical and oil processing industry. Statically stable liquid foam until now is used in technologic systems rather seldom. Although a usage of this type of foam as heat transfer agent in foam equipment has a number of advantages in comparison with one phase liquid equipment: small quantity of liquid is required, heat transfer rate is rather high, mass of equipment is much smaller, energy consumption for foam delivery into heat transfer zone is lower. The paper analyzes the peculiarities of heat transfer from distributed in staggered order and perpendicular to foam flow in channel of rectangular cross section tube bundle to the foam flow. It was estimated the dependence of mean gas velocity and volumetric void fraction of foam flow to heat transfer in downward foam flow. Significant difference of heat transfer intensity from front and back tubes of tube row in laminar foam flow was noticed. Dependence of heat transfer on flow velocity and volumetric void fraction of foam was confirmed and estimated by criterion equations.

  19. Rapid charging of thermal energy storage materials through plasmonic heating.

    Science.gov (United States)

    Wang, Zhongyong; Tao, Peng; Liu, Yang; Xu, Hao; Ye, Qinxian; Hu, Hang; Song, Chengyi; Chen, Zhaoping; Shang, Wen; Deng, Tao

    2014-01-01

    Direct collection, conversion and storage of solar radiation as thermal energy are crucial to the efficient utilization of renewable solar energy and the reduction of global carbon footprint. This work reports a facile approach for rapid and efficient charging of thermal energy storage materials by the instant and intense photothermal effect of uniformly distributed plasmonic nanoparticles. Upon illumination with both green laser light and sunlight, the prepared plasmonic nanocomposites with volumetric ppm level of filler concentration demonstrated a faster heating rate, a higher heating temperature and a larger heating area than the conventional thermal diffusion based approach. With controlled dispersion, we further demonstrated that the light-to-heat conversion and thermal storage properties of the plasmonic nanocomposites can be fine-tuned by engineering the composition of the nanocomposites.

  20. Impact of heat stress on conception rate of dairy cows in the moderate climate considering different temperature-humidity index thresholds, periods relative to breeding, and heat load indices.

    Science.gov (United States)

    Schüller, L K; Burfeind, O; Heuwieser, W

    2014-05-01

    The objectives of this retrospective study were to investigate the relationship between temperature-humidity index (THI) and conception rate (CR) of lactating dairy cows, to estimate a threshold for this relationship, and to identify periods of exposure to heat stress relative to breeding in an area of moderate climate. In addition, we compared three different heat load indices related to CR: mean THI, maximum THI, and number of hours above the mean THI threshold. The THI threshold for the influence of heat stress on CR was 73. It was statistically chosen based on the observed relationship between the mean THI at the day of breeding and the resulting CR. Negative effects of heat stress, however, were already apparent at lower levels of THI, and 1 hour of mean THI of 73 or more decreased the CR significantly. The CR of lactating dairy cows was negatively affected by heat stress both before and after the day of breeding. The greatest negative impact of heat stress on CR was observed 21 to 1 day before breeding. When the mean THI was 73 or more in this period, CR decreased from 31% to 12%. Compared with the average maximum THI and the total number of hours above a threshold of more than or 9 hours, the mean THI was the most sensitive heat load index relating to CR. These results indicate that the CR of dairy cows raised in the moderate climates is highly affected by heat stress.

  1. Water content influence on thermal and volumetric properties of wheat starch gelatinization under 10 MPa.

    Science.gov (United States)

    Orlowska, Marta; Randzio, Stanislaw L

    2010-02-01

    A transitiometric in situ analysis of wheat starch aqueous suspensions heated over a temperature range from 285 K to 415 K under isobaric conditions of 10 MPa is presented. Measurements were performed at four selected water concentrations: 56.0%, 64.7%, 73.5%, and 82.4% weight/water. Thermal and volumetric properties and their water content dependencies have been determined for three successive starch phase transformations occurred during wheat starch gelatinization.

  2. Visualization of volumetric seismic data

    Science.gov (United States)

    Spickermann, Dela; Böttinger, Michael; Ashfaq Ahmed, Khawar; Gajewski, Dirk

    2015-04-01

    Mostly driven by demands of high quality subsurface imaging, highly specialized tools and methods have been developed to support the processing, visualization and interpretation of seismic data. 3D seismic data acquisition and 4D time-lapse seismic monitoring are well-established techniques in academia and industry, producing large amounts of data to be processed, visualized and interpreted. In this context, interactive 3D visualization methods proved to be valuable for the analysis of 3D seismic data cubes - especially for sedimentary environments with continuous horizons. In crystalline and hard rock environments, where hydraulic stimulation techniques may be applied to produce geothermal energy, interpretation of the seismic data is a more challenging problem. Instead of continuous reflection horizons, the imaging targets are often steep dipping faults, causing a lot of diffractions. Without further preprocessing these geological structures are often hidden behind the noise in the data. In this PICO presentation we will present a workflow consisting of data processing steps, which enhance the signal-to-noise ratio, followed by a visualization step based on the use the commercially available general purpose 3D visualization system Avizo. Specifically, we have used Avizo Earth, an extension to Avizo, which supports the import of seismic data in SEG-Y format and offers easy access to state-of-the-art 3D visualization methods at interactive frame rates, even for large seismic data cubes. In seismic interpretation using visualization, interactivity is a key requirement for understanding complex 3D structures. In order to enable an easy communication of the insights gained during the interactive visualization process, animations of the visualized data were created which support the spatial understanding of the data.

  3. Studies on the Effects of Interphase Heat Exchange during Thermal Explosion in a Combustible Dusty Gas with General Arrhenius Reaction-Rate Laws

    Directory of Open Access Journals (Sweden)

    K. S. Adegbie

    2012-01-01

    Full Text Available A mathematical model for thermal explosion in a combustible dusty gas containing fuel droplets with general Arrhenius reaction-rate laws, convective and radiative heat losses, and interphase heat exchange between gas and inert solid particles is investigated. The objective of the study is to examine the effects of interphase heat exchange between the gas and solid particles on (i ignition of reacting gas, (ii accumulation of heat by the solid particles during combustion process (iii evaporation of the liquid fuel droplets, and (iv consumption of reacting gas concentration. The equations governing the physical model with realistic assumptions are stated and nondimensionalised leading to an intractable system of first-order coupled nonlinear differential equations, which is not amenable to exact methods of solution. Therefore, we present numerical solutions as well as different qualitative effects of varying interphase heat exchange parameter. Graphs and Table feature prominently to explain the results obtained.

  4. An Investigation of the High Rate Volumetric Properties of Snow.

    Science.gov (United States)

    1981-11-01

    1 o. t "r111’ us"’I by St .a~w’Iv~~ iadl . I u 1I ’I ’(1700: ~ ~ ~ ~ ~ ~ ~ ~ ~ a IW l’r-idi:f II a io t .i 1 lil J!’,U1 I ILI’’ intr11 1 i M",0 1011

  5. TO DEDUCTION OF MASS FLOW RATE FOR HELICAL HEAT EXCHANGER AT MULTIPLE CROSS-SECTIONS USING CFD

    OpenAIRE

    Surendra Kumar Vishwakarma*, Sanjay Kumbhare, K.K. Thakur

    2016-01-01

    Enhancing the heat transfer by the use of helical coils has been studied and researched by many researchers, because the fluid dynamics inside the pipes of a helical coil heat exchanger offer certain advantages over the straight tubes, shell and tube type heat exchanger, in terms of better heat transfer and mass transfer coefficients. Various configurations of coil structure are possible, and the configuration in which there is a series of vertically stacked helically coiled tubes is the most...

  6. 1-D diffusion based solidification model with volumetric expansion and shrinkage effect: A semi-analytical approach

    Science.gov (United States)

    Monde, Aniket D.; Chakraborty, Prodyut R.

    2017-10-01

    Volumetric expansion and shrinkage due to different densities of solid and liquid phases are common phenomena during solidification process. Simple analytical models addressing effect of volumetric expansion/shrinkage during solidification are rarely found. The few existing 1-D solidification models are valid only for semi-infinite domain with limitations of their application for finite domain size. The focus of the present work is to develop a 1-D semi-analytical solidification model addressing effects of volumetric expansion/shrinkage in a finite domain. The proposed semi-analytical scheme involves finding simultaneous solution of transient 1-D heat diffusion equations at solid and liquid domain coupled at the interface by Stefan condition. The change of the total domain length during solidification due to volumetric expansion/shrinkage is addressed by using mass conservation. For validation of the proposed model, solidification of water in a finite domain is studied without considering volumetric expansion/shrinkage effect and results are compared with those obtained from existing enthalpy updating based numerical model. After validation, case studies pertaining to volumetric expansion and shrinkage are performed considering solidification of water and paraffin respectively and physically consistent results are obtained. The study is relevant for understanding unidirectional crystal growth under the effect of controlled boundary condition.

  7. Combined surface and volumetric occlusion shading

    KAUST Repository

    Schott, Matthias O.

    2012-02-01

    In this paper, a method for interactive direct volume rendering is proposed that computes ambient occlusion effects for visualizations that combine both volumetric and geometric primitives, specifically tube shaped geometric objects representing streamlines, magnetic field lines or DTI fiber tracts. The proposed algorithm extends the recently proposed Directional Occlusion Shading model to allow the rendering of those geometric shapes in combination with a context providing 3D volume, considering mutual occlusion between structures represented by a volume or geometry. © 2012 IEEE.

  8. MR volumetric assessment of endolymphatic hydrops

    Energy Technology Data Exchange (ETDEWEB)

    Guerkov, R.; Berman, A.; Jerin, C.; Krause, E. [University of Munich, Department of Otorhinolaryngology Head and Neck Surgery, Grosshadern Medical Centre, Munich (Germany); University of Munich, German Centre for Vertigo and Balance Disorders, Grosshadern Medical Centre, Marchioninistr. 15, 81377, Munich (Germany); Dietrich, O.; Flatz, W.; Ertl-Wagner, B. [University of Munich, Institute of Clinical Radiology, Grosshadern Medical Centre, Munich (Germany); Keeser, D. [University of Munich, Institute of Clinical Radiology, Grosshadern Medical Centre, Munich (Germany); University of Munich, German Centre for Vertigo and Balance Disorders, Grosshadern Medical Centre, Marchioninistr. 15, 81377, Munich (Germany); University of Munich, Department of Psychiatry and Psychotherapy, Innenstadtkliniken Medical Centre, Munich (Germany)

    2014-10-16

    We aimed to volumetrically quantify endolymph and perilymph spaces of the inner ear in order to establish a methodological basis for further investigations into the pathophysiology and therapeutic monitoring of Meniere's disease. Sixteen patients (eight females, aged 38-71 years) with definite unilateral Meniere's disease were included in this study. Magnetic resonance (MR) cisternography with a T2-SPACE sequence was combined with a Real reconstruction inversion recovery (Real-IR) sequence for delineation of inner ear fluid spaces. Machine learning and automated local thresholding segmentation algorithms were applied for three-dimensional (3D) reconstruction and volumetric quantification of endolymphatic hydrops. Test-retest reliability was assessed by the intra-class coefficient; correlation of cochlear endolymph volume ratio with hearing function was assessed by the Pearson correlation coefficient. Endolymph volume ratios could be reliably measured in all patients, with a mean (range) value of 15 % (2-25) for the cochlea and 28 % (12-40) for the vestibulum. Test-retest reliability was excellent, with an intra-class coefficient of 0.99. Cochlear endolymphatic hydrops was significantly correlated with hearing loss (r = 0.747, p = 0.001). MR imaging after local contrast application and image processing, including machine learning and automated local thresholding, enable the volumetric quantification of endolymphatic hydrops. This allows for a quantitative assessment of the effect of therapeutic interventions on endolymphatic hydrops. (orig.)

  9. Temporal Coding of Volumetric Imagery

    Science.gov (United States)

    Llull, Patrick Ryan

    'Image volumes' refer to realizations of images in other dimensions such as time, spectrum, and focus. Recent advances in scientific, medical, and consumer applications demand improvements in image volume capture. Though image volume acquisition continues to advance, it maintains the same sampling mechanisms that have been used for decades; every voxel must be scanned and is presumed independent of its neighbors. Under these conditions, improving performance comes at the cost of increased system complexity, data rates, and power consumption. This dissertation explores systems and methods capable of efficiently improving sensitivity and performance for image volume cameras, and specifically proposes several sampling strategies that utilize temporal coding to improve imaging system performance and enhance our awareness for a variety of dynamic applications. Video cameras and camcorders sample the video volume (x,y,t) at fixed intervals to gain understanding of the volume's temporal evolution. Conventionally, one must reduce the spatial resolution to increase the framerate of such cameras. Using temporal coding via physical translation of an optical element known as a coded aperture, the compressive temporal imaging (CACTI) camera emonstrates a method which which to embed the temporal dimension of the video volume into spatial (x,y) measurements, thereby greatly improving temporal resolution with minimal loss of spatial resolution. This technique, which is among a family of compressive sampling strategies developed at Duke University, temporally codes the exposure readout functions at the pixel level. Since video cameras nominally integrate the remaining image volume dimensions (e.g. spectrum and focus) at capture time, spectral (x,y,t,lambda) and focal (x,y,t,z) image volumes are traditionally captured via sequential changes to the spectral and focal state of the system, respectively. The CACTI camera's ability to embed video volumes into images leads to exploration

  10. Factorial design for the evaluation of the interaction effect between particle size and heating rate in the kinetic energy of coal combustion

    Energy Technology Data Exchange (ETDEWEB)

    Avila, Ivonete; Silva, Eugenio A.G.; Mortari, Daniela A.; Crnkovic, Paula M.; Milioli, Fernando E. [University of Sao Paulo (EESC/USP), Sao Carlos, SP (Brazil). Engineering School. Group of Thermal and Fluids Engineering], Emails: iavila@sc.usp.br, eugenio.silva@usp.br, paulam@sc.usp.br, milioli@sc.usp.br

    2010-07-01

    This paper evaluates the behavior of kinetic energy for different heating rates ({alpha}) and particle sizes of the material in the study of the coal combustion process. It aims to obtain a response surface in a large range of particle size, using heating rates between the minimum and maximum values allowed by the equipment. Therefore it searches for a model to evaluate the interaction effect between particle size and the heating rate and to predict the activation energy of the process studied. The activation energy of the process was determined using the isoconversional model Model Free Kinetics. In this model, the activation energy (E{sub {alpha}}) is obtained as a function of the reaction extent ({alpha}). The subscript in E{sub {alpha}} designates the values related to a given value of conversion ({alpha}). All experiments were conducted in thermogravimetric balance using samples of a Brazilian coal (EC4500) witch average particle size between 163 to 650 {mu}m and heating rates between 10 and 40 deg C min{sup -1} in dynamic atmosphere of air. A central rotatable composite design was applied for the 2{sup 2} factorial design including 4 tests under the axial conditions and 3 repetitions in the central point. As expected, the results show that both the particle size and the heating rate affected significantly the values of activation energy of the coal combustion process obtained by the model used. (author)

  11. Evaluation of three thermal protection systems in a hypersonic high-heating-rate environment induced by an elevon deflected 30 deg

    Science.gov (United States)

    Taylor, A. H.; Jackson, L. R.; Weinstein, I.

    1977-01-01

    Three thermal protection systems proposed for a hypersonic research airplane were subjected to high heating rates in the Langley 8 foot, high temperature structures tunnel. Metallic heat sink (Lockalloy), reusable surface insulation, and insulator-ablator materials were each tested under similar conditions. The specimens were tested for a 10 second exposure on the windward side of an elevon deflected 30 deg. The metallic heat sink panel exhibited no damage; whereas the reusable surface insulation tiles were debonded from the panel and the insulator-ablator panel eroded through its thickness, thus exposing the aluminum structure to the Mach 7 environment.

  12. Radiative heating rates profiles associated with a springtime case of Bodélé and Sudan dust transport over West Africa

    Directory of Open Access Journals (Sweden)

    C. Lema^itre

    2010-09-01

    Full Text Available The radiative heating rate due to mineral dust over West Africa is investigated using the radiative code STREAMER, as well as remote sensing and in situ observations gathered during the African Monsoon Multidisciplinary Analysis Special Observing Period (AMMA SOP. We focus on two days (13 and 14 June 2006 of an intense and long lasting episode of dust being lifted in remote sources in Chad and Sudan and transported across West Africa in the African easterly jet region, during which airborne operations were conducted at the regional scale, from the southern fringes of the Sahara to the Gulf of Guinea. Profiles of heating rates are computed from airborne LEANDRE 2 (Lidar Embarqué pour l'étude de l'Atmosphère: Nuages Dynamique, Rayonnement et cycle de l'Eau and space-borne CALIOP (Cloud Aerosol Lidar and Infrared Pathfinder Satellite Observations lidar observations using two mineral dust model constrained by airborne in situ data and ground-based sunphotometer obtained during the campaign. Complementary spaceborne observations (from the Moderate-resolution Imaging Spectroradiometer-MODIS and in-situ observations such as dropsondes are also used to take into account the infrared contribution of the water vapour. We investigate the variability of the heating rate on the vertical within a dust plume, as well as the contribution of both shortwave and longwave radiation to the heating rate and the radiative heating rate profiles of dust during daytime and nighttime. The sensitivity of the so-derived heating rate is also analyzed for some key variables for which the associated uncertainties may be large. During daytime, the warming associated with the presence of dust was found to be between 1.5 K day−1 and 4 K day−1, on average, depending on altitude and latitude. Strong warming (i.e. heating rates as high as 8 K day−1 was also observed locally in some limited part of the dust plumes. The uncertainty on the

  13. Utility of birefringence changes due to collagen thermal denaturation rate process analysis: vessel wall temperature estimation for new short term heating balloon angioplasty

    Science.gov (United States)

    Kaneko, Kenji; Shimazaki, Natsumi; Gotoh, Maya; Nakatani, Eriko; Arai, Tsunenori

    2007-02-01

    Our photo thermal reaction heating architecture balloon realizes less than 10 s short term heating that can soften vessel wall collagen without damaging surrounding tissue thermally. New thermal balloon angioplasty, photo-thermo dynamic balloon angioplasty (PTDBA) has experimentally shown sufficient opening with 2 atm low pressure dilation and prevention of chronic phase restenosis and acute phase thrombus in vivo. Even though PTDBA has high therapeutic potential, the most efficient heating condition is still under study, because relationship of treatment and thermal dose to vessel wall is not clarified yet. To study and set the most efficient heating condition, we have been working on establishment of temperature history estimation method from our previous experimental results. Heating target of PTDBA, collagen, thermally denatures following rate process. Denaturation is able to be quantified with measured collagen birefringence value. To express the denaturation with equation of rate process, the following ex vivo experiments were performed. Porcine extracted carotid artery was soaked in two different temperature saline baths to enforce constant temperature heating. Higher temperature bath was set to 40 to 80 degree Celsius and soaking duration was 5 to 40 s. Samples were observed by a polarizing microscope and a scanning electron microscope. The birefringence was measured by polarizing microscopic system using Brace-Koehler compensator 1/30 wavelength. The measured birefringence showed temperature dependency and quite fit with the rate process equation. We think vessel wall temperature is able to be estimated using the birefringence changes due to thermal denaturation.

  14. Ultrahigh volumetric capacitance and cyclic stability of fluorine and nitrogen co-doped carbon microspheres

    Science.gov (United States)

    Zhou, Junshuang; Lian, Jie; Hou, Li; Zhang, Junchuan; Gou, Huiyang; Xia, Meirong; Zhao, Yufeng; Strobel, Timothy A.; Tao, Lu; Gao, Faming

    2015-09-01

    Highly porous nanostructures with large surface areas are typically employed for electrical double-layer capacitors to improve gravimetric energy storage capacity; however, high surface area carbon-based electrodes result in poor volumetric capacitance because of the low packing density of porous materials. Here, we demonstrate ultrahigh volumetric capacitance of 521 F cm-3 in aqueous electrolytes for non-porous carbon microsphere electrodes co-doped with fluorine and nitrogen synthesized by low-temperature solvothermal route, rivaling expensive RuO2 or MnO2 pseudo-capacitors. The new electrodes also exhibit excellent cyclic stability without capacitance loss after 10,000 cycles in both acidic and basic electrolytes at a high charge current of 5 A g-1. This work provides a new approach for designing high-performance electrodes with exceptional volumetric capacitance with high mass loadings and charge rates for long-lived electrochemical energy storage systems.

  15. Ni foam cathode enables high volumetric H2 production in a microbial electrolysis cell

    NARCIS (Netherlands)

    Jeremiasse, A.W.; Hamelers, H.V.M.; Saakes, M.; Buisman, C.J.N.

    2010-01-01

    Valuable, “green” H2 can be produced with a microbial electrolysis cell (MEC). To achieve a high volumetric production rate of high purity H2, a continuous flow MEC with an anion exchange membrane, a flow through bioanode and a flow through Ni foam cathode was constructed. At an electrical energy in

  16. Research, development, and testing of a prototype two-stage low-input rate oil burner for variable output heating system applications

    Energy Technology Data Exchange (ETDEWEB)

    Krajewski, R.F.; Butcher, T.A. [Brookhaven National Labs., Upton, NY (United States)

    1997-09-01

    The use of a Two-Stage Fan Atomized Oil Burner (TSFAB) in space and water heating applications will have dramatic advantages in terms of it`s potential for a high Annual Fuel Utilization Efficiency (AFUE) and/or Energy Factor (EF) rating for the equipment. While demonstrations of a single rate burner in an actual application have already yielded sufficient confidence that space and domestic heating loads can be met at a single low firing rate, this represents only a narrow solution to the diverse nature of building space heating and domestic water loads that the industry must address. The mechanical development, proposed control, and testing of the Two-Stage burner is discussed in terms of near term and long term goals.

  17. Acute cell death rate of vascular smooth muscle cells during or after short heating up to 20s ranging 50 to 60°C as a basic study of thermal angioplasty

    Science.gov (United States)

    Shinozuka, Machiko; Shimazaki, Natsumi; Ogawa, Emiyu; Machida, Naoki; Arai, Tsunenori

    2014-02-01

    We studied the relations between the time history of smooth muscle cells (SMCs) death rate and heating condition in vitro to clarify cell death mechanism in heating angioplasty, in particular under the condition in which intimal hyperplasia growth had been prevented in vivo swine experiment. A flow heating system on the microscope stage was used for the SMCs death rate measurement during or after the heating. The cells were loaded step-heating by heated flow using a heater equipped in a Photo-thermo dynamic balloon. The heating temperature was set to 37, 50-60°C. The SMCs death rate was calculated by a division of PI stained cell number by Hoechst33342 stained cell number. The SMCs death rate increased 5-10% linearly during 20 s with the heating. The SMCs death rate increased with duration up to 15 min after 5 s heating. Because fragmented nuclei were observed from approximately 5 min after the heating, we defined that acute necrosis and late necrosis were corresponded to within 5 min after the heating and over 5 min after the heating, respectively. This late necrosis is probably corresponding to apoptosis. The ratio of necrotic interaction divided the acute necrosis rate by the late necrosis was calculated based on this consideration as 1.3 under the particular condition in which intimal hyperplasia growth was prevented in vivo previous porcine experiment. We think that necrotic interaction rate is larger than expected rate to obtain intimal hyperplasia suppression.

  18. Buoyancy Driven Mixing with Continuous Volumetric Energy Deposition

    Science.gov (United States)

    Wachtor, Adam J.; Jebrail, Farzaneh F.; Dennisen, Nicholas A.; Andrews, Malcolm J.; Gore, Robert A.

    2014-11-01

    An experiment involving a miscible fluid pair is presented which transitioned from a Rayleigh-Taylor (RT) stable to RT unstable configuration through continuous volumetric energy deposition (VED) by microwave radiation. Initially a light, low microwave absorbing fluid rested above a heavier, more absorbing fluid. The alignment of the density gradient with gravity made the system stable, and the Atwood number (At) for the initial setup was approximately -0.12. Exposing the fluid pair to microwave radiation preferentially heated the bottom fluid, and caused its density to drop due to thermal expansion. As heating of the bottom fluid continued, the At varied from negative to positive, and after the system passed through the neutral stability point, At = 0, buoyancy driven mixing ensued. Continuous VED caused the At to continue increasing and further drive the mixing process. Successful VED mixing required careful design of the fluid pair used in the experiment. Therefore, fluid selection is discussed, along with challenges and limitations of data collection using the experimental microwave facility. Experimental and model predictions of the neutral stability point, and onset of buoyancy driven mixing, are compared, and differences with classical, constant At RT driven turbulence are discussed.

  19. Sideband cooling an ion to the quantum ground state in a Penning trap with very low heating rate

    CERN Document Server

    Goodwin, J F; Thompson, R C; Segal, D M

    2014-01-01

    We report the laser cooling of a single $^{40}\\text{Ca}^+$ ion in a Penning trap to the motional ground state in one dimension. Cooling is performed in the strong binding limit on the 729-nm electric quadrupole $S_{1/2}\\leftrightarrow D_{5/2}$ transition, broadened by a quench laser coupling the $D_{5/2}$ and $P_{3/2}$ levels. We find the final phonon number to be $\\bar{n}=0.012\\pm0.009$. We measure the heating rate of the trap to be exceptionally low with $\\dot{\\bar{n}}=0.08\\pm 0.12~\\textrm{s}^{-1}$ and a scaled spectral noise density of $\\omega S_{\\omega}<1.6\\times10^{-10}~\\textrm{V}^{2}\\textrm{m}^{-2}\\textrm{Hz}^{-1}\\textrm{s}^{-1}$, which is consistent with the large ion-electrode distance. We perform Rabi oscillations on the sideband-cooled ion and observe a coherence time of $0.7\\pm 0.1~\\textrm{ms}$, noting that the practical performance is limited primarily by the intensity noise of the probe laser.

  20. Measuring the shock-heating rate in the winds of O stars using X-ray line spectra

    CERN Document Server

    Cohen, David H; Gayley, Kenneth G; Owocki, Stanley P; Sundqvist, Jon O; Petit, Veronique; Leutenegger, Maurice A

    2014-01-01

    We present a new method for using measured X-ray emission line fluxes from O stars to determine the shock-heating rate due to instabilities in their radiation-driven winds. The high densities of these winds means that their embedded shocks quickly cool by local radiative emission, while cooling by expansion should be negligible. Ignoring for simplicity any non-radiative mixing or conductive cooling, the method presented here exploits the idea that the cooling post-shock plasma systematically passes through the temperature characteristic of distinct emission lines in the X-ray spectrum. In this way, the observed flux distribution among these X-ray lines can be used to construct the cumulative probability distribution of shock strengths that a typical wind parcel encounters as it advects through the wind. We apply this new method (Gayley 2014) to Chandra grating spectra from five O stars with X-ray emission indicative of embedded wind shocks in effectively single massive stars. Correcting for wind absorption of...

  1. Efficient determination of crystallisation and melting points at low cooling and heating rates with novel computer controlled equipment

    Energy Technology Data Exchange (ETDEWEB)

    Wachter, Philipp [Institut fuer Physikalische und Theoretische Chemie der Universitaet Regensburg, Universitaetsstrasse 31, D-93040 Regensburg (Germany); Schweiger, Hans-Georg [Institut fuer Physikalische und Theoretische Chemie der Universitaet Regensburg, Universitaetsstrasse 31, D-93040 Regensburg (Germany); Continental Automotive Systems Division, Sickingenstrasse 29-38, D-10553 Berlin (Germany); Wudy, Franz [Institut fuer Physikalische und Theoretische Chemie der Universitaet Regensburg, Universitaetsstrasse 31, D-93040 Regensburg (Germany); Gores, Heiner J. [Institut fuer Physikalische und Theoretische Chemie der Universitaet Regensburg, Universitaetsstrasse 31, D-93040 Regensburg (Germany)], E-mail: Heiner.Gores@Chemie.Uni-Regensburg.de

    2008-10-15

    We studied melting and solidification points of 14 pure solvents and two ionic liquids with a recently constructed automatic computer-controlled equipment, which is able to record simultaneously temperature-time functions of up to 30 samples at very low heating and cooling rates down to 1.5 K . h{sup -1}. The effects of viscosity of the studied samples and of carbon fibres as an added crystallisation aid were also investigated. Equilibrium temperatures for the solid-liquid phase transition are in accordance with literature for materials that were often checked, such as acetonitrile, showing the quality of our new equipment, whereas the value of the transition temperature of some other materials differed from published results. It is shown that both the viscosity of the material and carbon fibres as crystallisation aids have an effect on supercooling. The value given for the equilibrium point of the ionic liquid trioctylmethylammonium trifluorocetate T{sub tr} = (285.62 {+-} 0.1) K is new.

  2. Fatigue Crack Growth Rate and Fracture Resistance of Heat Affected Zone of Stainless Steel Narrow Gap Welds

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Ho Jung; Kim, Min U; Jang, Chang Heui [KAIST, Daejeon (Korea, Republic of); Cho, Sun Young [Korea Laboratory Engineering System, Daejeon (Korea, Republic of); Yang, Jun Seog [KEPCO, Daejeon (Korea, Republic of)

    2011-05-15

    In nuclear power plants, the automated narrow gap welding (NGW) technique has been widely used in joining stainless steel pipes in primary coolant system. As the primary system pipes are subjected to various transients during plant operation, cracks could initiate and propagate that would cause accidents. To prevent the cracking from developing into sudden failure in the primary system, leak-before-break (LBB) design concept has been developed and applied to many nuclear power plants. Meanwhile, to apply the LBB design, mechanical properties of the structural materials of piping systems should be evaluated, especially at weld zone and heat affected zone (HAZ), because mechanical properties within those regions show considerable scatter and spatial differences. In this study, fatigue crack grow rate (FCGR) and fracture resistance of base metal, weld zone, and HAZ of type 316L stainless steel narrow gap welds were performed at plant operating temperature (315 .deg. C) and room temperature. In particular, FCGR and fracture resistance of HAZ were evaluated in detail and compared to those of base metal

  3. A short-term rating method for heat pump heating systems; phase 5: test of the fault diagnosis systems; Kurztestmethode fuer Waermepumpenanlagen; Phase 5: Test der Fehlerdiagnosesysteme

    Energy Technology Data Exchange (ETDEWEB)

    Zogg, D.; Esfandiar, S.

    2001-07-01

    This final report for the Swiss Federal Office of Energy (SFOE) describes the testing phase of a project that developed systems for the operational monitoring and optimisation of heat pump installations along with a diagnosis system for faults. The heat pump is considered as a sub-system. The report describes two monitoring systems and a simulation model that are used to monitor the state of the heat pump both during commissioning as well as during operation. The aim is also to detect faults as early as possible during the whole of the operational life of the installation. A state-orientated approach is propagated as being cheaper than fixed service intervals or repairing after breakdown and standstill. The development of the two monitoring systems called 'HeatWatch' and 'FuzzyWatch' is described. The effort needed for the parametrisation and training of these systems is discussed. The testing of the systems on two test beds using real-life measured values for a single-family home and further simulation data is described and the results listed. The authors state that the monitoring systems can also be used for refrigeration and air-conditioning systems.

  4. MHD oscillatory channel flow, heat and mass transfer in a physiological fluid in presence of chemical reaction

    Directory of Open Access Journals (Sweden)

    J.C. Misra

    2016-03-01

    Full Text Available In the present paper, the problem of oscillatory MHD flow of blood in a porous arteriole in presence of chemical reaction and an external magnetic field has been investigated. Heat and mass transfer during arterial blood flow are also studied. A mathematical model is developed and analyzed by using appropriate mathematical techniques. Expressions for the velocity profile, volumetric flow rate, wall shear stress and rates of heat and mass transfer have been obtained. Variations of the said quantities with different parameters are computed by using MATHEMATICA software. The quantitative estimates are presented through graphs and table.

  5. The development and initial validation of a virtual dripping sweat rate and a clothing wetness ratio for use in predictive heat strain models

    Science.gov (United States)

    Kubota, H.; Kuwabara, K.; Hamada, Y.

    2014-08-01

    This paper applies the heat balance equation (HBE) for clothed subjects as a linear function of mean skin temperature ( t sk ) by a new sweating efficiency ( η sw ) and an approximation for the thermoregulatory sweat rate. The equation predicting t sk in steady state conditions was derived as the solution of the HBE and used for a predictive heat strain scale. The heat loss from the wet clothing (WCL) area was identified with a new variable of `virtual dripping sweat rate VDSR' ( S wdr ). This is a subject's un-evaporated sweat rate in dry clothing from the regional sweat rate exceeding the maximum evaporative capacity, and adds the moisture to the clothing, reducing the intrinsic clothing insulation. The S wdr allowed a mass balance analysis of the wet clothing area identified as clothing wetness ( w cl ). The w cl was derived by combining the HBE at the WCL surface from which the evaporation rate and skin heat loss from WCL region are given. Experimental results on eight young male subjects wearing typical summer clothing, T-shirt and trousers verified the model for predicting t sk with WCL thermal resistance ( R cl,w ) identified as 25 % of dry clothing ( R cl,d ).

  6. Volumetric Properties of the Mixture Trichloromethane CHCl3 + C2H3N Ethanenitrile (VMSD1111, LB4349_V)

    Science.gov (United States)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume C 'Binary Liquid Systems of Nonelectrolytes III' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Volumetric Properties of the Mixture Trichloromethane CHCl3 + C2H3N Ethanenitrile (VMSD1111, LB4349_V)' providing data from direct low-pressure measurement of mass density at variable mole fraction and constant temperature, in the single-phase region(s).

  7. Volumetric Properties of the Mixture Trichloromethane CHCl3 + C4H9Cl 1-Chlorobutane (VMSD1212, LB4573_V)

    Science.gov (United States)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume A 'Binary Liquid Systems of Nonelectrolytes I' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Volumetric Properties of the Mixture Trichloromethane CHCl3 + C4H9Cl 1-Chlorobutane (VMSD1212, LB4573_V)' providing data by calculation of molar excess volume from low-pressure density measurements at variable mole fraction and constant temperature.

  8. Volumetric Properties of the Mixture Trichloromethane CHCl3 + C6H6 Benzene (VMSD1111, LB3208_V)

    Science.gov (United States)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume A 'Binary Liquid Systems of Nonelectrolytes I' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Volumetric Properties of the Mixture Trichloromethane CHCl3 + C6H6 Benzene (VMSD1111, LB3208_V)' providing data from direct low-pressure measurement of mass density at variable mole fraction and constant temperature, in the single-phase region(s).

  9. A SUBDIVISION SCHEME FOR VOLUMETRIC MODELS

    Institute of Scientific and Technical Information of China (English)

    GhulamMustafa; LiuXuefeng

    2005-01-01

    In this paper, a subdivision scheme which generalizes a surface scheme in previous papers to volume meshes is designed. The scheme exhibits significant control over shrink-age/size of volumetric models. It also has the ability to conveniently incorporate boundaries and creases into a smooth limit shape of models. The method presented here is much simpler and easier as compared to MacCracken and Joy's. This method makes no restrictions on the local topology of meshes. Particularly, it can be applied without any change to meshes of nonmanifold topology.

  10. Volumetric composition in composites and historical data

    DEFF Research Database (Denmark)

    Lilholt, Hans; Madsen, Bo

    2013-01-01

    guidance to the optimal combination of fibre content, matrix content and porosity content, in order to achieve the best obtainable properties. Several composite materials systems have been shown to be handleable with this model. An extensive series of experimental data for the system of cellulose fibres...... and polymer (resin) was produced in 1942 – 1944, and these data have been (re-)analysed by the volumetric composition model, and the property values for density, stiffness and strength have been evaluated. Good agreement has been obtained and some further observations have been extracted from the analysis....

  11. IMITATION OF STANDARD VOLUMETRIC ACTIVITY METAL SAMPLES

    Directory of Open Access Journals (Sweden)

    A. I. Zhukouski

    2016-01-01

    Full Text Available Due to the specific character of problems in the field of ionizing radiation spectroscopy, the R&D and making process of standard volumetric activity metal samples (standard samples for calibration and verification of spectrometric equipment is not only expensive, but also requires the use of highly qualified experts and a unique specific equipment. Theoretical and experimental studies performed have shown the possibility to use imitators as a set of alternating point sources of gamma radiation and metal plates and their use along with standard volumetric activity metal samples for calibration of scintillation-based detectors used in radiation control in metallurgy. Response functions or instrumental spectra of such spectrometer to radionuclides like 137Cs, 134Cs, 152Eu, 154Eu, 60Co, 54Mn, 232Th, 226Ra, 65Zn, 125Sb+125mTe, 106Ru+106Rh, 94Nb, 110mAg, 233U, 234U, 235U and 238U are required for calibration in a given measurement geometry. Standard samples in the form of a probe made of melt metal of a certain diameter and height are used in such measurements. However, the production of reference materials is costly and even problematic for such radionuclides as 94Nb, 125Sb+125mTe, 234U, 235U  etc. A recognized solution to solve this problem is to use the Monte-Carlo simulation method. Instrumental experimental and theoretical spectra obtained by using standard samples and their imitators show a high compliance between experimental spectra of real samples and the theoretical ones of their Monte-Carlo models, between spectra of real samples and the ones of their imitators and finally, between experimental spectra of real sample imitators and the theoretical ones of their Monte-Carlo models. They also have shown the adequacy and consistency of the approach in using a combination of metal scattering layers and reference point gamma-ray sources instead of standard volumetric activity metal samples. As for using several reference point gamma-ray sources

  12. Joule heating and anomalous resistivity in the solar corona

    Directory of Open Access Journals (Sweden)

    S. R. Spangler

    2009-06-01

    Full Text Available Recent radioastronomical observations of Faraday rotation in the solar corona can be interpreted as evidence for coronal currents, with values as large as 2.5×109 Amperes (Spangler, 2007. These estimates of currents are used to develop a model for Joule heating in the corona. It is assumed that the currents are concentrated in thin current sheets, as suggested by theories of two dimensional magnetohydrodynamic turbulence. The Spitzer result for the resistivity is adopted as a lower limit to the true resistivity. The calculated volumetric heating rate is compared with an independent theoretical estimate by Cranmer et al. (2007. This latter estimate accounts for the dynamic and thermodynamic properties of the corona at a heliocentric distance of several solar radii. Our calculated Joule heating rate is less than the Cranmer et al estimate by at least a factor of 3×105. The currents inferred from the observations of Spangler (2007 are not relevant to coronal heating unless the true resistivity is enormously increased relative to the Spitzer value. However, the same model for turbulent current sheets used to calculate the heating rate also gives an electron drift speed which can be comparable to the electron thermal speed, and larger than the ion acoustic speed. It is therefore possible that the coronal current sheets are unstable to current-driven instabilities which produce high levels of waves, enhance the resistivity and thus the heating rate.

  13. The Effect of Cooling Rate after Homogenization on the Microstructure and Properties of 2017a Alloy Billets for Extrusion with Solution Heat Treatment on the Press

    Directory of Open Access Journals (Sweden)

    Woźnicki A.

    2016-09-01

    Full Text Available The influence of cooling rate after homogenization on the 2017A alloy microstructure was analysed. The capability of the θ (Al2Cu particles, precipitated during various homogenization coolings, for rapid dissolution was estimated. For this purpose, the DSC test was used to determine the effect of the cooling rate after homogenization on the course of melting during a rapid heating. Moreover, the samples after solution heat treatment (with short time annealing and ageing, were subjected to the microstructure investigations and the microhardness of grains interiors measurements. It was found that cooling after homogenization at 160 °C/h is sufficient for precipitation of fine θ phase particles, which dissolve during the subsequent rapid heating. The cooling at 40 °C/h, causes the precipitation of θ phase in the form of large particles, incapable of further fast dissolution.

  14. Tingkat Insidensi Malaria di Wilayah Pemanasan Kelambu Berinsektisida Tahan Lama dan Wilayah Kontrol (MALARIA INCIDENCE RATE OF HEAT ASSISTED REGENERATION LONG LASTING INSECTICIDAL NETS AREA AND CONTROL

    Directory of Open Access Journals (Sweden)

    Etih Sudarnika

    2012-03-01

    Full Text Available Long lasting insecticidal nets (LLIN is one effective way to prevent malaria. Permethrin treatedLLIN is one type of LLIN which is recommended by WHO. Several studies have shown that these types ofLLIN requiring heat assisted regeneration after washing to enhance the biological activity of insecticidethat contained in the LLIN fibers. This study aimed to compare the incidence rates of malaria in childrenunder five years old who live in the intervention area (where the heat assisted regeneration on LLIN afterwashing was applied and control area (where the heat assisted regeneration on LLIN after washing wasnot applied. Data of malaria cases was collected from laboratory log book at all health centers in BangkaDistrict, in the period of June June 2007 until July 2008. Data were analyzed with Poisson regressionmodels. The results showed that the incidence rate of malaria in children under five years old was notsignificantly different between the treatment and control areas.

  15. The Deformation Rate of Smooth Muscle Cells in Vessel Walls After Short-Duration Heating Dilatation in a Porcine Model Ex Vivo and In Vivo.

    Science.gov (United States)

    Kunio, Mie; Arai, Tsunenori

    2012-09-01

    We have proposed a novel short-duration thermal angioplasty with uniform temperature distribution. Although the dilatation mechanism of our short-duration heating dilatation was reported in our previous study, the influences on smooth muscle cells (SMCs) are not sufficiently understood. We studied the influences on SMCs in terms of shape change and discussed the relationship between the SMCs' shape change and dilatation mechanism ex vivo and in vivo. We found that the SMCs were fixed in the stretched condition after our short-duration heating dilatation both ex vivo and in vivo. The deformation rate of SMCs' shape, measured by the cells' nuclei, was increased with rising balloon maximum temperature (T(balloon)), and the same tendency was observed for the arterial dilatation rate. We hypothesize that the SMCs were fixed in the stretched condition because the arterial dilatation with our short-duration heating dilatation was performed without any plastic deformations of the vessel wall, causing the vessel wall itself to be stretched. We also prospect that the reasons for the positive correlation between the deformation rate of SMCs' shape and T(balloon) are that (i) the area heated over 60 °C was expanded with rising T(balloon), and (ii) the arterial dilatation rate was also increased with rising T(balloon).

  16. Modification of the Ti40Cu36Zr10Pd14 BMG Crystallization Mechanism with Heating Rates 10-140 K/min

    Science.gov (United States)

    Czeppe, T.; Sypien, A.; Wierzbicka-Miernik, A.

    2016-12-01

    The article presents investigations of Ti40Cu36Zr10Pd14 bulk metallic glass crystallization process heated with the rates of 10, 60, 100 and 140 K/min. High heating rates experiments were performed in a new type of differential scanning calorimeter equipped with a fast responding thermal sensor. Phase composition and microstructure were studied with x-ray diffraction and transmission electron microscopy. The observed crystallization proceeded in two separate steps. Applied high rates of heating/cooling resulted in the crystallization of only one CuTi phase, replacing typical multi-phase crystallization. The microstructure after crystallization was polycrystalline with some amount of amorphous phase retained. Kinetic parameters were determined with the use of the Kissinger and Friedman iso-conversional analysis and Matusita-Sakka iso-kinetic model. The kinetic analysis supplies results concerning autocatalytically activated mechanism of primary crystallization with decreasing activation energy and small density of quenched-in nuclei, in good agreement with previous structural investigations. The mechanism of secondary crystallization required dense nuclei site, increasing activation energy and large nucleation frequency. The amorphous phase of Ti40Cu36Zr10Pd14 BMG revealed high thermal stability against crystallization. Application of high heating rates in DSC experiments might be useful for the determination of mechanism and kinetic parameters in investigations of metallic glasses crystallization, giving reasonable results.

  17. Thermoluminescent response of LiF before variation of the heating rate; Respuesta termoluminiscente de LiF ante variacion de la tasa de calentamiento

    Energy Technology Data Exchange (ETDEWEB)

    Barrios, R. [Facultad de Quimica, UAEM, 50000 Toluca, Estado de Mexico (Mexico); Avila, O. [ININ, 52045 Ocoyoacac, Estado de Mexico (Mexico)

    2003-07-01

    Comparisons of glow curves of lithium fluoride dosemeters TLD-100 measured to two heating rates with the purpose of quantifying the change in the temperature of the peaks 5 and 7 for the thermoluminescent reader equipment Harshaw 4000 of the thermoluminescence laboratory of the ININ were carried out. (Author)

  18. On-Line Measurement of Heat of Combustion of Gaseous Hydrocarbon Fuel Mixtures

    Science.gov (United States)

    Sprinkle, Danny R.; Chaturvedi, Sushil K.; Kheireddine, Ali

    1996-01-01

    A method for the on-line measurement of the heat of combustion of gaseous hydrocarbon fuel mixtures has been developed and tested. The method involves combustion of a test gas with a measured quantity of air to achieve a preset concentration of oxygen in the combustion products. This method involves using a controller which maintains the fuel (gas) volumetric flow rate at a level consistent with the desired oxygen concentration in the combustion products. The heat of combustion is determined form a known correlation with the fuel flow rate. An on-line computer accesses the fuel flow data and displays the heat of combustion measurement at desired time intervals. This technique appears to be especially applicable for measuring heats of combustion of hydrocarbon mixtures of unknown composition such as natural gas.

  19. Melting of nanoparticle-enhanced phase change material inside an enclosure heated by laminar heat transfer fluid flow

    Science.gov (United States)

    Elbahjaoui, Radouane; El Qarnia, Hamid; El Ganaoui, Mohammed

    2016-05-01

    The proposed work presents a numerical investigation of the melting of a phase change material (PCM: Paraffin wax P116) dispersed with nanoparticles (Al2O3) in a latent heat storage unit (LHSU). The latter is composed of a number of vertical and identical slabs of nano-enhanced phase change material (NEPCM) separated by rectangular channels through which passes heat transfer fluid (HTF: water). A mathematical model based on the conservation equations of mass, momentum and energy has been developed. The resulting equations are discretized using the finite volume approach. The numerical model has been validated by experimental and numerical results published in literature. Numerical investigations have been conducted to evaluate the effects of the volumetric fraction of nanoparticles, HTF mass flow rate and inlet temperature on the latent heat storage unit's thermal behaviour and performance. Modelling results show that the volumetric fraction, HTF mass flow rate and inlet temperature need to be designed to achieve a significant improvement in thermal performance. Contribution to the topical issue "Materials for Energy Harvesting, Conversion and Storage (ICOME 2015) - Elected submissions", edited by Jean-Michel Nunzi, Rachid Bennacer and Mohammed El Ganaoui

  20. The effect of nonlinearity in CO2 heating rates on the attribution of stratospheric ozone and temperature changes

    Directory of Open Access Journals (Sweden)

    T. G. Shepherd

    2009-11-01

    Full Text Available An analysis of the attribution of past and future changes in stratospheric ozone and temperature to anthropogenic forcings is presented. The analysis is an extension of the study of Shepherd and Jonsson (2008 who analyzed chemistry-climate simulations from the Canadian Middle Atmosphere Model (CMAM and attributed both past and future changes to changes in the external forcings, i.e. the abundances of ozone-depleting substances (ODS and well-mixed greenhouse gases. The current study is based on a new CMAM dataset and includes two important changes. First, we account for the nonlinear radiative response to changes in CO2. It is shown that over centennial time scales the radiative response in the upper stratosphere to CO2 changes is significantly nonlinear and that failure to account for this effect leads to a significant error in the attribution. To our knowledge this nonlinearity has not been considered before in attribution analysis, including multiple linear regression studies. For the regression analysis presented here the nonlinearity was taken into account by using CO2 heating rate, rather than CO2 abundance, as the explanatory variable. This approach yields considerable corrections to the results of the previous study and can be recommended to other researchers. Second, an error in the way the CO2 forcing changes are implemented in the CMAM was corrected, which significantly affects the results for the recent past. As the radiation scheme, based on Fomichev et al. (1998, is used in several other models we provide some description of the problem and how it was fixed.

  1. Convective heat-transfer rate distributions over a 140 deg blunt cone at hypersonic speeds in different gas environments

    Science.gov (United States)

    Stewart, David A.; Chen, Y. K.

    1993-01-01

    Experiments were conducted in air, CO2, and CO2-argon gas mixtures to obtain heating distribution data over a 140 deg blunt cone with various corner radii. The effect of corner radius on the heating distribution over the forebody of the cone was included in the investigation. These experiments provide data for validation of two-dimensional axisymmetric and three-dimensional Navier-Stokes solutions. Heating distribution data and measured bow shock wave stand-off distances for 0 deg angle of attack were compared with predicted values using a two-dimensional axisymmetric Navier-Stokes code.

  2. The characterization of neural tissue ablation rate and corresponding heat affected zone of a 2 micron Tm3+ doped fiber laser(Conference Presentation)

    Science.gov (United States)

    Marques, Andrew J.; Jivraj, Jamil; Reyes, Robnier; Ramjist, Joel; Gu, Xijia J.; Yang, Victor X. D.

    2017-02-01

    Tissue removal using electrocautery is standard practice in neurosurgery since tissue can be cut and cauterized simultaneously. Thermally mediated tissue ablation using lasers can potentially possess the same benefits but with increased precision. However, given the critical nature of the spine, brain, and nerves, the effects of direct photo-thermal interaction on neural tissue needs to be known, yielding not only high precision of tissue removal but also increased control of peripheral heat damage. The proposed use of lasers as a neurosurgical tool requires that a common ground is found between ablation rates and resulting peripheral heat damage. Most surgical laser systems rely on the conversion of light energy into heat resulting in both desirable and undesirable thermal damage to the targeted tissue. Classifying the distribution of thermal energy in neural tissue, and thus characterizing the extent of undesirable thermal damage, can prove to be exceptionally challenging considering its highly inhomogenous composition when compared to other tissues such as muscle and bone. Here we present the characterization of neural tissue ablation rate and heat affected zone of a 1.94 micron thulium doped fiber laser for neural tissue ablation. In-Vivo ablation of porcine cerebral cortex is performed. Ablation volumes are studied in association with laser parameters. Histological samples are taken and examined to characterize the extent of peripheral heat damage.

  3. Assessment of external heat transfer coefficient during oocyte vitrification in liquid and slush nitrogen using numerical simulations to determine cooling rates.

    Science.gov (United States)

    Santos, M V; Sansinena, M; Zaritzky, N; Chirife, J

    2012-01-01

    In oocyte vitrification, plunging directly into liquid nitrogen favor film boiling and strong nitrogen vaporization. A survey of literature values of heat transfer coefficients (h) for film boiling of small metal objects with different geometries plunged in liquid nitrogen revealed values between 125 to 1000 W per per square m per K. These h values were used in a numerical simulation of cooling rates of two oocyte vitrification devices (open-pulled straw and Cryotop), plunged in liquid and slush nitrogen conditions. Heat conduction equation with convective boundary condition was considered a linear mathematical problem and was solved using the finite element method applying the variational formulation. COMSOL Multiphysics was used to simulate the cooling process of the systems. Predicted cooling rates for OPS and Cryotop when cooled at -196 degree C (liquid nitrogen) or -207 degree C (average for slush nitrogen) for heat transfer coefficients estimated to be representative of film boiling, indicated lowering the cooling temperature produces only a maximum 10 percent increase in cooling rates; confirming the main benefit of plunging in slush over liquid nitrogen does not arise from their temperature difference. Numerical simulations also demonstrated that a hypothetical four-fold increase in the cooling rate of vitrification devices when plunging in slush nitrogen would be explained by an increase in heat transfer coefficient. This improvement in heat transfer (i.e., high cooling rates) in slush nitrogen is attributed to less or null film boiling when a sample is placed in slush (mixture of liquid and solid nitrogen) because it first melts the solid nitrogen before causing the liquid to boil and form a film.

  4. Free-Standing T-Nb₂O₅/Graphene Composite Papers with Ultrahigh Gravimetric/Volumetric Capacitance for Li-Ion Intercalation Pseudocapacitor.

    Science.gov (United States)

    Kong, Lingping; Zhang, Chuanfang; Wang, Jitong; Qiao, Wenming; Ling, Licheng; Long, Donghui

    2015-11-24

    Free-standing electrodes with high gravimetric/volumetric capacitance will open up potential applications in miniaturized consumer electronics. Herein, we report a simple synthesis technology of free-standing orthorhombic Nb2O5 (T-Nb2O5)/graphene composite papers for Li-intercalating pseudocapacitive electrodes. Through a facile polyol-mediated solvothermal reaction, the Nb2O5 nanodots are homogeneously decorated onto the surface of reduced graphite oxide (rGO), which can form a homogeneous Nb2O5/rGO colloidal suspension that can be easily fabricated into flexible composite papers. The heat-treated T-Nb2O5/graphene composite papers exhibit a nanoporous layer-stacked structure with good ionic-electric conductive pathways, high T-Nb2O5 loading of 74.2%, and high bulk density of 1.55 g cm(-3). Such T-Nb2O5/graphene composite papers show a superior pseudocapacitor performance as free-standing electrodes, as evidenced by an ultrahigh gravimetric/volumetric capacitance (620.5 F g(-1) and 961.8 F cm(-3) at 1 mV s(-1)) and excellent rate capability. Furthermore, an organic electrolyte-based asymmetric supercapacitor is assembled based on T-Nb2O5/graphene composite papers, which can deliver a high energy density of 47 W h kg(-1) and power density of 18 kW kg(-1).

  5. Effects of Nitrogen Volumetric Flow Rate on Properties of MAO/TiN Composite Coatings on AZ31B Magnesium Alloy%氮气流量对AZ31B镁合金表面MAO/TiN涂层性能的影响

    Institute of Scientific and Technical Information of China (English)

    崔学军; 魏劲松; 宁闯明; 金永中; 林修洲

    2017-01-01

    为了提高镁合金的装饰性及耐腐抗磨性能,采用微弧氧化(MAO)和多弧离子镀技术制备了MAO/TiN复合涂层.利用SEM、XRD、纳米压痕仪及电化学工作站等考察氮气(N2)流量对涂层结构及性能的影响.结果表明:随着N2流量的增加,TiN涂层的颜色由淡黄色到金黄色再到红黄色变化,涂层表面的熔滴粒子数量增多,大尺寸颗粒数量减少,膜层更致密;涂层硬度和耐腐抗磨性能先增大后降低;当N2流量为130 mL/min时,涂层表现出较高的硬度(13.6 GPa)、较低的磨损量(0.8 mg)和自腐蚀电流密度(约1.6 μA/cm2).N2流量通过控制涂层中N/Ti原子的比例决定了涂层的颜色、微结构、物相组成及性能,涂层内部的孔隙、微裂纹等结构缺陷是导致涂层耐腐抗磨性能较差的关键因素.%To improve the decorativeness,corrosion and wear resistance of magnesium (Mg) alloys,an MAO/TiN composite coating was prepared through combing the micro-arc oxidation (MAO) with multi-arc ion plating on AZ31B Mg alloy.The effects of N2 volumetric flow rate on the structure and properties of the coating were investigated using SEM,XRD,nanometer indentation tester and electrochemical test system.The results indicate that with N2 increasing,the color of TiN layer is changed from light yellow to gold yellow and finally brownish red;the droplet particle is increased in number but the particles with larger size are reduced;and the coating becomes more denser.These cause the hardness,corrosion and wear resistance of the coating to increase first and then decrease.The coating presente higher hardness (13.6 GPa),lower wear rate (0.8 mg) and corrosion current density (1.6 μA/cm2) at 130 mL/min.The rate of N/Ti atoms is tailored through the N2 flow rate,so it can be concludes that the N2 flow rate should be responsible for the color,micro-structure,phase composition,corrosion and wear resistance of the coating.The defects like pores and cracks are playing key

  6. Experimental study on convection heat transfer and air drag in sinter layer

    Institute of Scientific and Technical Information of China (English)

    潘利生; 魏小林; 彭岩; 时小宝; 刘怀亮

    2015-01-01

    Convection heat transfer coefficient and air pressure drop in sinter layer are important factors for the design of sinter cooling craft. Due to the lack of necessary data, the two parameters are studied by experimental method. The experimental results show that heat conduction of sinter impacts the measurement of convection heat transfer coefficient. Convection heat transfer increases with the increase of air volumetric flow rate. Sinter layer without small particles (sample I) gives higher convection heat transfer coefficient than that with small particles (sample II). Under the considered conditions, volumetric convection heat transfer coefficient is in the range of 400−1800 W/(m3·°C). Air pressure drop in sinter layer increases with the increase of normal superficial velocity, as well as with the rise of air temperature. Additionally, air pressure drop also depends on sinter particle size distribution. In considered experimental conditions, pressure drop in sinter sample II is 2−3 times that in sinter sample I, which resulted from 17% small scale particles in sinter sample II.

  7. Impact of aerosol vertical distribution on aerosol direct radiative effect and heating rate in the Mediterranean region

    Science.gov (United States)

    Pappas, Vasileios; Hatzianastassiou, Nikolaos; Matsoukas, Christos; Koras Carracca, Mario; Kinne, Stefan; Vardavas, Ilias

    2015-04-01

    It is now well-established that aerosols cause an overall cooling effect at the surface and a warming effect within the atmosphere. At the top of the atmosphere (TOA), both positive and negative forcing can be found, depending on a number of other factors, such as surface albedo and relative position of clouds and aerosols. Whilst aerosol surface cooling is important due to its relation with surface temperature and other bio-environmental reasons, atmospheric heating is of special interest as well having significant impacts on atmospheric dynamics, such as formation of clouds and subsequent precipitation. The actual position of aerosols and their altitude relative to clouds is of major importance as certain types of aerosol, such as black carbon (BC) above clouds can have a significant impact on planetary albedo. The vertical distribution of aerosols and clouds has recently drawn the attention of the aerosol community, because partially can account for the differences between simulated aerosol radiative forcing with various models, and therefore decrease the level of our uncertainty regarding aerosol forcing, which is one of our priorities set by IPCC. The vertical profiles of aerosol optical and physical properties have been studied by various research groups around the world, following different methodologies and using various indices in order to present the impact of aerosols on radiation on different altitudes above the surface. However, there is still variability between the published results as to the actual effect of aerosols on shortwave radiation and on heating rate within the atmosphere. This study uses vertical information on aerosols from the Max Planck Aerosol Climatology (MAC-v1) global dataset, which is a combination of model output with quality ground-based measurements, in order to provide useful insight into the vertical profile of atmospheric heating for the Mediterranean region. MAC-v1 and the science behind this aerosol dataset have already

  8. Direct Radiative Effect and Heating Rate of black carbon aerosol: high time resolution measurements and source-identified forcing effects

    Science.gov (United States)

    Ferrero, Luca; Mocnik, Grisa; Cogliati, Sergio; Comi, Alberto; Degni, Francesca; Di Mauro, Biagio; Colombo, Roberto; Bolzacchini, Ezio

    2016-04-01

    Black carbon (BC) absorbs sunlight in the atmosphere heating it. However, up to now, heating rate (HR) calculations from the divergence of the net radiative flux with altitude or from the modelling activity are too sparse. This work fills the aforementioned gap presenting a new methodology based on a full set of physical equations to experimentally determine both the radiative power density absorbed into a ground-based atmospheric layer (ADRE), and the consequent HR induced by the absorptive component of aerosol. In urban context, it is essentially related to the BC. The methodology is also applicable to natural components (i.e. dust) and is obtained solving the first derivative of the main radiative transfer equations. The ADRE and the consequent HR can be determined coupling spectral aerosol absorption measurements with the spectrally resolved measurements of the direct, diffuse downward radiation and the surface reflected radiance components. Moreover, the spectral absorption of BC aerosol allows its source apportionment (traffic and biomass burning (BB)) allowing the same apportionment on HR. This work reports one year of high-time resolution measurements (5 min) of sunlight absorption and HR induced by BC aerosol over Milan. A unique sampling site was set up from March 2015 with: 1) Aethalometer (AE-31, Magee Scientific, 7-λ), 2) the Multiplexer-Radiometer-Irradiometer which detects downward and reflected radiance (350-1000 nm in 3648 spectral bands) coupled with a rotating shadow-band to measure spectrally-resolved global and diffuse radiation (thus direct), 3) a meteorological station (LSI-Lastem) equipped with 3 pyranometers (global, diffuse and refrected radiation; 300-3000 nm), a thermohygrometer, a barometer, an anemometer, 4) condensation and optical particle counters (TSI 3775 and Grimm 1.107), 5) low volume sampler (FAI Hydra dual sampler, PM2.5 and PM10) for sample collection and chemistry determination. Results concerning the radiative power

  9. A new heating strategy in electrothermal atomic absorption spectrometry for better absorbance-time curves at high atomization rate

    Energy Technology Data Exchange (ETDEWEB)

    Torsi, Giancarlo [Department of Chemistry G. Ciamician, University of Bologna, Via F. Selmi 2, 40126 Bologna (Italy)]. E-mail: giancarlo.torsi@unibo.it; Zattoni, Andrea [Department of Chemistry G. Ciamician, University of Bologna, Via F. Selmi 2, 40126 Bologna (Italy); Locatelli, Clinio [Department of Chemistry G. Ciamician, University of Bologna, Via F. Selmi 2, 40126 Bologna (Italy); Valcher, Sergio [Department of Chemistry G. Ciamician, University of Bologna, Via F. Selmi 2, 40126 Bologna (Italy)

    2005-03-31

    The results previously obtained by using fast heating in electrothermal atomic absorption spectrometry are considerably improved by using a new heating sequence which can be summarized as transverse-longitudinal heating mode. The absorbance vs. time curves, obtained with the new heating mode, follow almost perfectly a simple model in which only diffusion is considered as the force acting on the atomic vapor. From the fitting of the experimental absorbance vs. time data points with theoretical values, it is possible to calculate both the absorbance, when all atoms injected are assumed to be present, and their diffusion coefficient. Both values can be calculated by a simple software approach without the operator intervention. The asymptotic absorbance calculated in this way is the maximum absorbance physically obtainable and is the basis for standardless analysis.

  10. Investigation of the influence of groundwater advection on energy extraction rates for sustainable borehole heat exchanger operation

    Science.gov (United States)

    Schelenz, Sophie; Dietrich, Peter; Vienken, Thomas

    2016-04-01

    A sustainable thermal exploitation of the shallow subsurface requires a precise understanding of all relevant heat transport processes. Currently, planning practice of shallow geothermal systems (especially for systems financial investment. Finally, an evaluation approach is presented that classifies relevant heat transport processes according to their Péclet number to enable a first quantitative assessment of the subsurface energy regime and recommend further investigation and planning procedures.

  11. Peripheral Sweat Gland Function, but not Whole-Body Sweat Rate, Increases in Women Following Humid Heat Acclimation

    Science.gov (United States)

    2009-10-01

    Specifically. following heat acclimation (HA) both men and women demonstrate similar reductions in traditional indicators of physiological stress. such as...stress. Environ. Res. 37, 1-11. Lee, J., Bae. J .. Matsumoto, T., Yang. H., Min, Y .. 2009. Tropical malaysians and temperate Koreans exhibit...E.R.W.e. (Eds.). Perspectives in Exercise Sciences and Sports Medicine Volume 6, Exercise. Heat, and Thermoregulation .. Brown Publishers. pp.85-118

  12. Parametric analysis of air–water heat recovery concept applied to HVAC systems: Effect of mass flow rates

    OpenAIRE

    Mohamad Ramadan; Mostafa Gad El Rab; Mahmoud Khaled

    2015-01-01

    In the last three decades, the world has experienced enormous increases in energy and fuel consumption as a consequence of the economic and population growth. This causes renewable energy and energy recovery to become a requirement in building designs rather than option. The present work concerns a coupling between energy recovery and Heating, Ventilating and Air Conditioning HVAC domains and aims to apply heat recovery concepts to HVAC applications working on refrigeration cycles. It particu...

  13. Effects of magnesium-based hydrogen storage materials on the thermal decomposition, burning rate, and explosive heat of ammonium perchlorate-based composite solid propellant.

    Science.gov (United States)

    Liu, Leili; Li, Jie; Zhang, Lingyao; Tian, Siyu

    2017-08-24

    MgH2, Mg2NiH4, and Mg2CuH3 were prepared, and their structure and hydrogen storage properties were determined through X-ray photoelectron spectroscopy and thermal analyzer. The effects of MgH2, Mg2NiH4, and Mg2CuH3 on the thermal decomposition, burning rate, and explosive heat of ammonium perchlorate-based composite solid propellant were subsequently studied. Results indicated that MgH2, Mg2NiH4, and Mg2CuH3 can decrease the thermal decomposition peak temperature and increase the total released heat of decomposition. These compounds can improve the effect of thermal decomposition of the propellant. The burning rates of the propellant increased using Mg-based hydrogen storage materials as promoter. The burning rates of the propellant also increased using MgH2 instead of Al in the propellant, but its explosive heat was not enlarged. Nonetheless, the combustion heat of MgH2 was higher than that of Al. A possible mechanism was thus proposed. Copyright © 2017. Published by Elsevier B.V.

  14. Propellant Vaporization as a Criterion for Rocket-Engine Design; Experimental Performance, Vaporization and Heat-Transfer Rates with Various Propellant Combinations

    Science.gov (United States)

    Clark, Bruce J.; Hersch, Martin; Priem, Richard J.

    1959-01-01

    Experimental combustion efficiencies of eleven propellant combinations were determined as a function of chamber length. Efficiencies were measured in terms of characteristic exhaust velocities at three chamber lengths and in terms of gas velocities. The data were obtained in a nominal 200-pound-thrust rocket engine. Injector and engine configurations were kept essentially the same to allow comparison of the performance. The data, except for those on hydrazine and ammonia-fluorine, agreed with predicted results based on the assumption that vaporization of the propellants determines the rate of combustion. Decomposition in the liquid phase may be.responsible for the anomalous behavior of hydrazine. Over-all heat-transfer rates were also measured for each combination. These rates were close to the values predicted by standard heat-transfer calculations except for the combinations using ammonia.

  15. Disentangling volumetric and hydrational properties of proteins.

    Science.gov (United States)

    Voloshin, Vladimir P; Medvedev, Nikolai N; Smolin, Nikolai; Geiger, Alfons; Winter, Roland

    2015-02-05

    We used molecular dynamics simulations of a typical monomeric protein, SNase, in combination with Voronoi-Delaunay tessellation to study and analyze the temperature dependence of the apparent volume, Vapp, of the solute. We show that the void volume, VB, created in the boundary region between solute and solvent, determines the temperature dependence of Vapp to a major extent. The less pronounced but still significant temperature dependence of the molecular volume of the solute, VM, is essentially the result of the expansivity of its internal voids, as the van der Waals contribution to VM is practically independent of temperature. Results for polypeptides of different chemical nature feature a similar temperature behavior, suggesting that the boundary/hydration contribution seems to be a universal part of the temperature dependence of Vapp. The results presented here shine new light on the discussion surrounding the physical basis for understanding and decomposing the volumetric properties of proteins and biomolecules in general.

  16. All Photons Imaging Through Volumetric Scattering

    Science.gov (United States)

    Satat, Guy; Heshmat, Barmak; Raviv, Dan; Raskar, Ramesh

    2016-01-01

    Imaging through thick highly scattering media (sample thickness ≫ mean free path) can realize broad applications in biomedical and industrial imaging as well as remote sensing. Here we propose a computational “All Photons Imaging” (API) framework that utilizes time-resolved measurement for imaging through thick volumetric scattering by using both early arrived (non-scattered) and diffused photons. As opposed to other methods which aim to lock on specific photons (coherent, ballistic, acoustically modulated, etc.), this framework aims to use all of the optical signal. Compared to conventional early photon measurements for imaging through a 15 mm tissue phantom, our method shows a two fold improvement in spatial resolution (4db increase in Peak SNR). This all optical, calibration-free framework enables widefield imaging through thick turbid media, and opens new avenues in non-invasive testing, analysis, and diagnosis. PMID:27683065

  17. A Technique for Volumetric CSG Based on Morphology

    DEFF Research Database (Denmark)

    Bærentzen, Jakob Andreas; Christensen, Niels Jørgen

    2001-01-01

    In this paper, a new technique for volumetric CSG is presented. The technique requires the input volumes to correspond to solids which fulfill a voxelization suitability criterion. Assume the CSG operation is union. The volumetric union of two such volumes is defined in terms of the voxelization...

  18. Standard Test Method for Measuring Extreme Heat-Transfer Rates from High-Energy Environments Using a Transient, Null-Point Calorimeter

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2008-01-01

    1.1 This test method covers the measurement of the heat-transfer rate or the heat flux to the surface of a solid body (test sample) using the measured transient temperature rise of a thermocouple located at the null point of a calorimeter that is installed in the body and is configured to simulate a semi-infinite solid. By definition the null point is a unique position on the axial centerline of a disturbed body which experiences the same transient temperature history as that on the surface of a solid body in the absence of the physical disturbance (hole) for the same heat-flux input. 1.2 Null-point calorimeters have been used to measure high convective or radiant heat-transfer rates to bodies immersed in both flowing and static environments of air, nitrogen, carbon dioxide, helium, hydrogen, and mixtures of these and other gases. Flow velocities have ranged from zero (static) through subsonic to hypersonic, total flow enthalpies from 1.16 to greater than 4.65 × 101 MJ/kg (5 × 102 to greater than 2 × 104 ...

  19. Validation and recovery rates of an indirect calorimetry headbox system used to measure heat production of cattle

    Science.gov (United States)

    A headbox system was constructed at the University of Nebraska-Lincoln to determine heat production from dairy cattle using indirect calorimetry. The system was designed for use in a tie-stall barn to allow the animal to be comfortable and was mounted on wheels to transport between animals between s...

  20. Increase of production rate of RE-123 film by PLD system with the hot-wall type heating

    Energy Technology Data Exchange (ETDEWEB)

    Kakimoto, K., E-mail: kkakimoto@fujikura.co.j [Fujikura Ltd., 1440 Mutsuzaki, Sakura, Chiba 285-8550 (Japan); Fuji, H.; Igarashi, M.; Hanada, Y.; Hanyu, S.; Hayashida, T.; Tashita, C.; Kutami, H.; Iijima, Y.; Saitoh, T. [Fujikura Ltd., 1440 Mutsuzaki, Sakura, Chiba 285-8550 (Japan)

    2009-10-15

    We have studied two types of heating systems to produce thick GdBa{sub 2}Cu{sub 3}O{sub 7-X} (Gd123) films with high critical current (I{sub c}) stably at a high speed by the PLD method. Material yields of both PLD systems reached about 50-60% by optimization of evaporation condition. Hot-wall heating type (type 2) could fabricate the thicker Gd123 film with the higher I{sub c} compared to contact heating type (type 1) and maximum I{sub c} reached 1040 A at about 6 mum thick. Furthermore, it was estimated that type 2 could fabricate Gd123 film with an I{sub c} of about 700 A at about twice speed compared to type 1. Finally, it was considered that the hot-wall heating type was very advantageous to prepare thick Gd123 film with high I{sub c} at a high speed from the system structure.

  1. The Variations of Thermal Contact Resistance and Heat Transfer Rate of the AlN Film Compositing with PCM

    Directory of Open Access Journals (Sweden)

    Huann-Ming Chou

    2015-01-01

    Full Text Available The electrical industries have been fast developing over the past decades. Moreover, the trend of microelements and packed division multiplex is obviously for the electrical industry. Hence, the high heat dissipative and the electrical insulating device have been popular and necessary. The thermal conduct coefficient of aluminum nitride (i.e., AlN is many times larger than the other materials. Moreover, the green technology of composite with phase change materials (i.e., PCMs is worked as a constant temperature cooler. Therefore, PCMs have been used frequently for saving energy and the green environment. Based on the above statements, it does show great potential in heat dissipative for the AlN film compositing with PCM. Therefore, this paper is focused on the research of thermal contact resistance and heat transfer between the AlN/PCM pairs. According to the experimental results, the heat transfer decreases and the thermal contact resistance increases under the melting process of PCM. However, the suitable parameters such as contact pressures can be used to improve the above defects.

  2. Ignition delays, heats of combustion, and reaction rates of aluminum alkyl derivatives used as ignition and combustion enhancers for supersonic combustors

    Science.gov (United States)

    Ryan, T. W., III; Harlowe, W. W.; Schwab, S.

    1992-01-01

    The work was based on adapting an apparatus and procedure developed at Southwest Research Institute for rating the ignition quality of fuels for diesel engines. Aluminum alkyls and various Lewis-base adducts of these materials, both neat and mixed 50/50 with pure JP-10 hydrocarbon, were injected into the combustion bomb using a high-pressure injection system. The bomb was pre-charged with air that was set at various initial temperatures and pressures for constant oxygen density. The ignition delay times were determined for the test materials at these different initial conditions. The data are presented in absolute terms as well as comparisons with the parent alkyls. The relative heats of reaction of the various test materials were estimated based on a computation of the heat release, using the pressure data recorded during combustion in the bomb. In addition, the global reaction rates for each material were compared at a selected tmperature and pressure.

  3. Optimum bleeding rate of open loop ground source heat pump systems determined by hydrogeological modeling in Korea

    Science.gov (United States)

    Jeon, W. H.; Kim, N.; Lee, J. Y.

    2014-12-01

    This study aims to evaluate the influence of open loop ground source heat pump systems operation on hydrological conditions of aquifer. Test bed is located in Chuncheon, Korea. The step drawdown test was conducted in five stages for 300 minutes. The variation of groundwater levels by open loop ground source heat pump systems operation was estimated using Visual MODFLOW. Transmissivity ranged from 2.02×10-4 to 9.36×10-4, and storage coefficient ranged from 0.00067 to 0.021. The amount of optimum bleeding was calculated to be 240 m3/day. When bleeding will be 50, 90, 240 and 450 m3/day for 5 years, groundwater levels may decrease 1.84, 3.31, 8.89 and 17.0 m, respectively. If the amount of bleeding is 50 m3/day, the influence of bleeding will not reach the boundary regions of the Soyang River after 5 years. Regarding the open loop ground source heat pump system installed at the test bed, the amount of optimum bleeding in accordance with the stand are proposed by the government is 90 m3/day, which is 20% of the 450 m3/day circulation quantity of the system. However, if continuous bleeding of more than 90 m3/day occurs, then the radius of influence is expected to reach the boundary regions of the Soyang River after 5 years. These results indicate that amount of optimum bleeding differ in each open loop ground soured heat pump system. Therefore, the debate for the amount of optimum bleeding in open loop ground source heat pump systems is demanded. This work is supported by the Energy Efficiency and Resources of the Korea Institute of Energy Technology Evaluation and Planning (KETEP) grant funded by the Korea government Ministry of Knowledge Economy (No.20123040110010).

  4. Impact of Turbocharger Non-Adiabatic Operation on Engine Volumetric Efficiency and Turbo Lag

    Directory of Open Access Journals (Sweden)

    S. Shaaban

    2012-01-01

    Full Text Available Turbocharger performance significantly affects the thermodynamic properties of the working fluid at engine boundaries and hence engine performance. Heat transfer takes place under all circumstances during turbocharger operation. This heat transfer affects the power produced by the turbine, the power consumed by the compressor, and the engine volumetric efficiency. Therefore, non-adiabatic turbocharger performance can restrict the engine charging process and hence engine performance. The present research work investigates the effect of turbocharger non-adiabatic performance on the engine charging process and turbo lag. Two passenger car turbochargers are experimentally and theoretically investigated. The effect of turbine casing insulation is also explored. The present investigation shows that thermal energy is transferred to the compressor under all circumstances. At high rotational speeds, thermal energy is first transferred to the compressor and latter from the compressor to the ambient. Therefore, the compressor appears to be “adiabatic” at high rotational speeds despite the complex heat transfer processes inside the compressor. A tangible effect of turbocharger non-adiabatic performance on the charging process is identified at turbocharger part load operation. The turbine power is the most affected operating parameter, followed by the engine volumetric efficiency. Insulating the turbine is recommended for reducing the turbine size and the turbo lag.

  5. Performance investigation of evaporatively-cooled heat exchangers - part one: plain and finned tubes

    Energy Technology Data Exchange (ETDEWEB)

    Hasan, A.; Siren, K.

    2004-07-01

    The performance of two evaporatively cooled heat exchangers is investigated under similar operating conditions of airflow rates and inlet hot water temperatures. The types of the heat exchangers are plain and plate-finned circular tube which occupy the same volume. A substantial increase in heat transfer takes place for the plate-finned tubes. The increase is 92-140% for air velocities from 1.66 to 3.57 m s{sup -1}. The wet-finned surfaces show low fin efficiency compared with dry surfaces. An energy index defined as the ratio of volumetric thermal conductance to air pressure drop per unit length is found to be close for the two heat exchangers. This reveals higher thermal utilisation of the occupied volume by the finned tubes with the same energy index. (orig.)

  6. Contraction of radiator length in heavy vehicles using cerium oxide nanofluid by enhancing heat transfer performance

    Directory of Open Access Journals (Sweden)

    Ramalingam Senthil

    2016-01-01

    Full Text Available In this present investigation, heat transfer performance of CeO2-ethylene glycol as coolants in heat pipes are analyzed. Various concentrations of 0.5, 0.75, 1.0, 1.25, 1.5, and 2.0 vol.% with different volumetric flow 1.0, 2.0, 3.0, 3.5, and 4.0 lpm at a temperature of 40°C, are investigated experimentally and the results are numerically analyzed by means of cross tube heat exchanger and horizontal flow with twist plate insert. The results are scrutinized to evaluate the best concentration which will reduce the size of the existing radiator length. The results demonstrated that, for 0.75 vol.% combination of CeO2-ethylene glycol resulted in increase of heat transfer coefficient compared to the combination of water-ethylene glycol. Increase in volumetric flow rate of the coolant increase the heat transfer coefficient results in the contraction of radiator length. Replacing the original coolant with the proposed combination, it is estimated that the size of the radiator, inventory of the fluid, and pumping power is reduced, thus, making this nanofluid an energy efficient fluid for the engine cooling system.

  7. Development and numerical/experimental characterization of a lab-scale flat flame reactor allowing the analysis of pulverized solid fuel devolatilization and oxidation at high heating rates

    Science.gov (United States)

    Lemaire, R.; Menanteau, S.

    2016-01-01

    This paper deals with the thorough characterization of a new experimental test bench designed to study the devolatilization and oxidation of pulverized fuel particles in a wide range of operating conditions. This lab-scale facility is composed of a fuel feeding system, the functioning of which has been optimized by computational fluid dynamics. It allows delivering a constant and time-independent mass flow rate of fuel particles which are pneumatically transported to the central injector of a hybrid McKenna burner using a carrier gas stream that can be inert or oxidant depending on the targeted application. A premixed propane/air laminar flat flame stabilized on the porous part of the burner is used to generate the hot gases insuring the heating of the central coal/carrier-gas jet with a thermal gradient similar to those found in industrial combustors (>105 K/s). In the present work, results issued from numerical simulations performed a priori to characterize the velocity and temperature fields in the reaction chamber have been analyzed and confronted with experimental measurements carried out by coupling particle image velocimetry, thermocouple and two-color pyrometry measurements so as to validate the order of magnitude of the heating rate delivered by such a new test bench. Finally, the main features of the flat flame reactor we developed have been discussed with respect to those of another laboratory-scale system designed to study coal devolatilization at a high heating rate.

  8. Development and numerical/experimental characterization of a lab-scale flat flame reactor allowing the analysis of pulverized solid fuel devolatilization and oxidation at high heating rates

    Energy Technology Data Exchange (ETDEWEB)

    Lemaire, R., E-mail: romain.lemaire@mines-douai.fr; Menanteau, S. [Mines Douai, EI, F-59508 Douai (France)

    2016-01-15

    This paper deals with the thorough characterization of a new experimental test bench designed to study the devolatilization and oxidation of pulverized fuel particles in a wide range of operating conditions. This lab-scale facility is composed of a fuel feeding system, the functioning of which has been optimized by computational fluid dynamics. It allows delivering a constant and time-independent mass flow rate of fuel particles which are pneumatically transported to the central injector of a hybrid McKenna burner using a carrier gas stream that can be inert or oxidant depending on the targeted application. A premixed propane/air laminar flat flame stabilized on the porous part of the burner is used to generate the hot gases insuring the heating of the central coal/carrier-gas jet with a thermal gradient similar to those found in industrial combustors (>10{sup 5} K/s). In the present work, results issued from numerical simulations performed a priori to characterize the velocity and temperature fields in the reaction chamber have been analyzed and confronted with experimental measurements carried out by coupling particle image velocimetry, thermocouple and two-color pyrometry measurements so as to validate the order of magnitude of the heating rate delivered by such a new test bench. Finally, the main features of the flat flame reactor we developed have been discussed with respect to those of another laboratory-scale system designed to study coal devolatilization at a high heating rate.

  9. Levels of potassium, uranium, thorium and rate of radiogenic heat production in the bedrock adjacent to Camamu and Almada sedimentary basins, Bahia, Brazil; Teores de potassio, uranio, torio e taxa de producao de calor radiogenico no embasamento adjacente as bacias sedimentares de Camamu e Almada, Bahia, Brasil

    Energy Technology Data Exchange (ETDEWEB)

    Sapucaia, Najara Santos; Barbosa, Johildo Salomao Figueiredo [Instituto de Geociencias, Universidade Federal da Bahia, Salvador, BA (Brazil); Argollo, Roberto Max de, E-mail: nss@cpgg.ufba.br, E-mail: johildo@cpgg.ufba.br, E-mail: robmax@ufba.br [Laboratorio de Fisica Nuclear Aplicada, Instituto de Fisica, Universidade Federal da Bahia, Salvador, BA (Brazil)

    2005-10-15

    The bedrock adjacent to Camamu and Almada sedimentary basins is characterized mainly by rocks of granulite and amphibolite facies, with archaean and paleoproterozoic ages, which belong to orogen Itabuna-Salvador-Curaca. The units in major proportion in this context are the metatonalites associated with basic and metamonzonites belonging to Itabuna belt. In smaller area occur the Teolandia granite and the Moenda granodiorite associated with the Ipiau band amphibolites, the charnockites and charnoenderbites of Jequie bloc, the neoproterozoic sienites and the mafic dikes. The K, U and Th contents of the rocks vary from 0,02 to 6,33% for K, from < 0,2 to 9,10 ppm for U and from < 0,4 to 64,38 ppm for Th. These contents are higher in the charnockites, Moenda granodiorite, Teolandia granite and sienites, intermediate in the metatonalites and metamonzonites and lower in the basic granulites. The heat production rates are higher in the lithologies where K, U and Th are also higher, varying from 0,58 to 5,57 {mu}W m{sup -3}. The coverage areas of such lithologies are, however, small compared with that of the metatonalitic granulites, metamonzonitic granulites and sienites where the rates vary from 0,10 to 1,44 {mu}W m{sup -3}, 0,23 to 5,55 {mu}W m{sup -3} and 0,60 to 2,24 {mu}W m{sup -3}, respectively. In this case, the heat production rates vary from 0,10 to 1,44 {mu}W m{sup -3}. The basic granulites have the smaller rates, from 0,06 to 0,36 {mu}W m-3. The observation of the lithologies in the margins of the two basins suggest that, in the bedrock under the younger sediments, may predominate the metatonalites, followed by the metamonzonites, with some significant participation of sienites in the Almada basin. In those lithologies, the volumetric heat production rates, with one standard deviation range, are 0,41 +- 0,30 {mu}W m{sup -3} for metatonalites, 0,71 +- 0,57 {mu}W m{sup -3} for metamonzonites and 1,20 +- 0,51 {mu}W m{sup -3} for sienites. (author)

  10. Malone-Brayton Cycle Engine/Heat Pump.

    Science.gov (United States)

    A machine, such as a heat pump , and having an all liquid heat exchange fluid, operates over a more nearly ideal thermodynamic cycle by adjustment of...difference in axial lengths of rotary pumps of the gear or vane type to achieve the adjustment of volumetric capacity. Adjustment of the heat pump system

  11. A new contrast-assisted method in microcirculation volumetric flow assessment

    Science.gov (United States)

    Lu, Sheng-Yi; Chen, Yung-Sheng; Yeh, Chih-Kuang

    2007-03-01

    Microcirculation volumetric flow rate is a significant index in diseases diagnosis and treatment such as diabetes and cancer. In this study, we propose an integrated algorithm to assess microcirculation volumetric flow rate including estimation of blood perfused area and corresponding flow velocity maps based on high frequency destruction/contrast replenishment imaging technique. The perfused area indicates the blood flow regions including capillaries, arterioles and venules. Due to the echo variance changes between ultrasonic contrast agents (UCAs) pre- and post-destruction two images, the perfused area can be estimated by the correlation-based approach. The flow velocity distribution within the perfused area can be estimated by refilling time-intensity curves (TICs) after UCAs destruction. Most studies introduced the rising exponential model proposed by Wei (1998) to fit the TICs. Nevertheless, we found the TICs profile has a great resemblance to sigmoid function in simulations and in vitro experiments results. Good fitting correlation reveals that sigmoid model was more close to actual fact in describing destruction/contrast replenishment phenomenon. We derived that the saddle point of sigmoid model is proportional to blood flow velocity. A strong linear relationship (R = 0.97) between the actual flow velocities (0.4-2.1 mm/s) and the estimated saddle constants was found in M-mode and B-mode flow phantom experiments. Potential applications of this technique include high-resolution volumetric flow rate assessment in small animal tumor and the evaluation of superficial vasculature in clinical studies.

  12. Measurement Accuracy of Heart Rate and Respiratory Rate during Graded Exercise and Sustained Exercise in the Heat Using the Zephyr BioHarness™

    OpenAIRE

    Kim, J. -H.; Roberge, R.; Powell, J. B.; Shafer, A. B.; Williams, W. Jon

    2012-01-01

    The Zephyr BioHarness™ was tested to determine the accuracy of heart rate (HR) and respiratory rate (RR) measurements during 2 exercise protocols in conjunction with either a laboratory metabolic cart (Vmax) or a previously validated portable metabolic system (K4b2). In one protocol, HR and RR were measured using the BioHarness and Vmax during a graded exercise up to V̇O2max (n = 12). In another protocol, HR and RR were measured using the BH and K4b2 during sustained exercise (30 % and 50 % V...

  13. EFFECTS OF TEST TEMPERATURE AND STRAIN RATE ON THE MECHANICAL PROPERTIES IN AN INTERCRITICALLY HEAT-TREATED BAINITE-TRANSFORMED STEEL

    Institute of Scientific and Technical Information of China (English)

    Z. Li; D. Wu

    2004-01-01

    Larger amount of austenite could be retained in an intercritically heat-treated bainitetransformed steel. The elongation and the strength-ductility balance of the steel could be enhanced considerably due to strain-induced martensite transformation and transformationinduced plasticity (TRIP) of retained austenite. The effects of test temperature and strain rate on the mechanical properties and strain induced transformation behavior of retained austenite in the steel were investigated. Total elongation and strength-ductility balance of the specimen reached maximum when it strained at a strain rate of 2.8×10-4s-1 and at 350℃. The relation between test temperature and tensile properties showed the same tendency at three kinds of strain rates. Flow stress increased considerably with decreasing the strain rate.

  14. Soil volumetric water content measurements using TDR technique

    Directory of Open Access Journals (Sweden)

    S. Vincenzi

    1996-06-01

    Full Text Available A physical model to measure some hydrological and thermal parameters in soils will to be set up. The vertical profiles of: volumetric water content, matric potential and temperature will be monitored in different soils. The volumetric soil water content is measured by means of the Time Domain Reflectometry (TDR technique. The result of a test to determine experimentally the reproducibility of the volumetric water content measurements is reported together with the methodology and the results of the analysis of the TDR wave forms. The analysis is based on the calculation of the travel time of the TDR signal in the wave guide embedded in the soil.

  15. Iterative reconstruction of volumetric particle distribution

    Science.gov (United States)

    Wieneke, Bernhard

    2013-02-01

    For tracking the motion of illuminated particles in space and time several volumetric flow measurement techniques are available like 3D-particle tracking velocimetry (3D-PTV) recording images from typically three to four viewing directions. For higher seeding densities and the same experimental setup, tomographic PIV (Tomo-PIV) reconstructs voxel intensities using an iterative tomographic reconstruction algorithm (e.g. multiplicative algebraic reconstruction technique, MART) followed by cross-correlation of sub-volumes computing instantaneous 3D flow fields on a regular grid. A novel hybrid algorithm is proposed here that similar to MART iteratively reconstructs 3D-particle locations by comparing the recorded images with the projections calculated from the particle distribution in the volume. But like 3D-PTV, particles are represented by 3D-positions instead of voxel-based intensity blobs as in MART. Detailed knowledge of the optical transfer function and the particle image shape is mandatory, which may differ for different positions in the volume and for each camera. Using synthetic data it is shown that this method is capable of reconstructing densely seeded flows up to about 0.05 ppp with similar accuracy as Tomo-PIV. Finally the method is validated with experimental data.

  16. Physiological and performance adaptations to an in-season soccer camp in the heat: Associations with heart rate and heart rate variability

    DEFF Research Database (Denmark)

    Buchheit, M; Voss, S C; Nybo, Lars

    2011-01-01

    ) activity, plasma volume (PV) changes, and post-5-min run rate of perceived exertion (RPE) were collected at six occasions in temperate environmental conditions (22°C). Players also performed the yo-yo intermittent recovery test level 1 (Yo-Yo IR1) in the same environmental conditions (22°C), both...

  17. Basal metabolic rate of endotherms can be modeled using heat-transfer principles and physiological concepts: reply to "can the basal metabolic rate of endotherms be explained by biophysical modeling?".

    Science.gov (United States)

    Roberts, Michael F; Lightfoot, Edwin N; Porter, Warren P

    2011-01-01

    Our recent article (Roberts et al. 2010 ) proposes a mechanistic model for the relation between basal metabolic rate (BMR) and body mass (M) in mammals. The model is based on heat-transfer principles in the form of an equation for distributed heat generation within the body. The model can also be written in the form of the allometric equation BMR = aM(b), in which a is the coefficient of the mass term and b is the allometric exponent. The model generates two interesting results: it predicts that b takes the value 2/3, indicating that BMR is proportional to surface area in endotherms. It also provides an explanation of the physiological components that make up a, that is, respiratory heat loss, core-skin thermal conductance, and core-skin thermal gradient. Some of the ideas in our article have been questioned (Seymour and White 2011 ), and this is our response to those questions. We specifically address the following points: whether a heat-transfer model can explain the level of BMR in mammals, whether our test of the model is inadequate because it uses the same literature data that generated the values of the physiological variables, and whether geometry and empirical values combine to make a "coincidence" that makes the model only appear to conform to real processes.

  18. Heat pumps in combined heat and power systems

    DEFF Research Database (Denmark)

    Ommen, Torben Schmidt; Markussen, Wiebke Brix; Elmegaard, Brian

    2014-01-01

    of the considered cases. When considering a case where the heat pump is located at a CHP (combined heat and power) plant, a configuration that increases the DH return temperature proposes the lowest operation cost, as low as 12 EUR MWh-1 for a 90 °C e 40 °C DH network. Considering the volumetric heating capacity......Heat pumps have previously been proposed as a way to integrate higher amounts of renewable energy in DH (district heating) networks by integrating, e.g., wind power. The paper identifies and compares five generic configurations of heat pumps in DH systems. The operational performance......, a third configuration is superior in all cases. Finally, the three most promising heat pump configurations are integrated in a modified PQ-diagram of the CHP plant. Each show individual advantages, and for two, also disadvantages in order to achieve flexible operation....

  19. Characterizing volumetric deformation behavior of naturally occuring bituminous sand materials

    CSIR Research Space (South Africa)

    Anochie-Boateng, Joseph

    2009-05-01

    Full Text Available newly proposed hydrostatic compression test procedure. The test procedure applies field loading conditions of off-road construction and mining equipment to closely simulate the volumetric deformation and stiffness behaviour of oil sand materials. Based...

  20. Hyperspectral image classification based on volumetric texture and dimensionality reduction

    Science.gov (United States)

    Su, Hongjun; Sheng, Yehua; Du, Peijun; Chen, Chen; Liu, Kui

    2015-06-01

    A novel approach using volumetric texture and reduced-spectral features is presented for hyperspectral image classification. Using this approach, the volumetric textural features were extracted by volumetric gray-level co-occurrence matrices (VGLCM). The spectral features were extracted by minimum estimated abundance covariance (MEAC) and linear prediction (LP)-based band selection, and a semi-supervised k-means (SKM) clustering method with deleting the worst cluster (SKMd) bandclustering algorithms. Moreover, four feature combination schemes were designed for hyperspectral image classification by using spectral and textural features. It has been proven that the proposed method using VGLCM outperforms the gray-level co-occurrence matrices (GLCM) method, and the experimental results indicate that the combination of spectral information with volumetric textural features leads to an improved classification performance in hyperspectral imagery.

  1. Designing remote web-based mechanical-volumetric flow meter ...

    African Journals Online (AJOL)

    ... remote web-based mechanical-volumetric flow meter reading systems based on ... damage and also provides the ability to control and manage consumption. ... existing infrastructure of the telecommunications is used in data transmission.

  2. Effects of heat release rate on NOx time history in diesel combustion; Diesel nensho ni okeru netsu hasseiritsu keika ga NOx nodo rireki ni oyobosu eikyo

    Energy Technology Data Exchange (ETDEWEB)

    Ishiyama, T.; Miwa, K.; Higashida, M. [Tokushima Univ., Tokushima (Japan). Faculty of Engineering; Watanabe, S. [Kawasaki Heavy Industries, Ltd., Kobe (Japan)

    1996-06-25

    For determining the optimum combination of combustion control techniques to reduce NOx emission from diesel engines, it is important to clarify the effects of each technique not only on the NOx emission but also on its time history during combustion. In this paper, NOx concentration in the combustion chamber of a rapid compression machine has been measured by using a total gas sampling method. In order to elucidate the relation between NOx history and heat release rate, air temperatures nozzle hole size and air motion are varied to control the heat release process. The results show that NOx emission is not solely dependent upon initial combustion. Air utilization in the main diffusive combustion phase has great influence on NOx formation and its decay. NOx formation is accelerated by activation of the initial stage of the main combustion when using a nozzle with small holes. 9 refs., 13 figs.

  3. The heat-compression technique for the conversion of platelet-rich fibrin preparation to a barrier membrane with a reduced rate of biodegradation.

    Science.gov (United States)

    Kawase, Tomoyuki; Kamiya, Mana; Kobayashi, Mito; Tanaka, Takaaki; Okuda, Kazuhiro; Wolff, Larry F; Yoshie, Hiromasa

    2015-05-01

    Platelet-rich fibrin (PRF) was developed as an advanced form of platelet-rich plasma to eliminate xenofactors, such as bovine thrombin, and it is mainly used as a source of growth factor for tissue regeneration. Furthermore, although a minor application, PRF in a compressed membrane-like form has also been used as a substitute for commercially available barrier membranes in guided-tissue regeneration (GTR) treatment. However, the PRF membrane is resorbed within 2 weeks or less at implantation sites; therefore, it can barely maintain sufficient space for bone regeneration. In this study, we developed and optimized a heat-compression technique and tested the feasibility of the resulting PRF membrane. Freshly prepared human PRF was first compressed with dry gauze and subsequently with a hot iron. Biodegradability was microscopically examined in vitro by treatment with plasmin at 37°C or in vivo by subcutaneous implantation in nude mice. Compared with the control gauze-compressed PRF, the heat-compressed PRF appeared plasmin-resistant and remained stable for longer than 10 days in vitro. Additionally, in animal implantation studies, the heat-compressed PRF was observed at least for 3 weeks postimplantation in vivo whereas the control PRF was completely resorbed within 2 weeks. Therefore, these findings suggest that the heat-compression technique reduces the rate of biodegradation of the PRF membrane without sacrificing its biocompatibility and that the heat-compressed PRF membrane easily could be prepared at chair-side and applied as a barrier membrane in the GTR treatment.

  4. THE DESIGN ERROR ESTIMATION OF THE HEAT TRANSFER RATE IN THE HEAT PIPE EXCHANGER%热管换热器换热量设计误差估算

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The deviations of the design indexes from the real values of heat exchanger performance are the matters of customer's and manufacturer's common concern. Up till now, the estimating method has no unifiable understanding. For this reason much controversy is often given rise to .This paper presents an estimating method for the design calculation error of the heat transfer rate in the heat pipe exchanger .Error theory is employed to investigate a practical example. Five error sources are found and the results of mathematical analysis are given.%换热器性能的设计指标与实际值偏差的大小,是用户和制造厂家共同关心的问题。目前对这种偏差的估算方法及估算值指标尚未形成共识,因此时有争议发生。本文提出了热管换热器换热量设计误差的估算方法,并以锅炉烟气余热回收装置中的重力热管换热器为例,运用误差理论进行分析计算,找出了产生换热量设计偏差的5个误差源,并给出了计算结果。

  5. Increasing the volumetric efficiency of Diesel engines by intake pipes

    Science.gov (United States)

    List, Hans

    1933-01-01

    Development of a method for calculating the volumetric efficiency of piston engines with intake pipes. Application of this method to the scavenging pumps of two-stroke-cycle engines with crankcase scavenging and to four-stroke-cycle engines. The utility of the method is demonstrated by volumetric-efficiency tests of the two-stroke-cycle engines with crankcase scavenging. Its practical application to the calculation of intake pipes is illustrated by example.

  6. Serial volumetric registration of pulmonary CT studies

    Science.gov (United States)

    Silva, José Silvestre; Silva, Augusto; Sousa Santos, Beatriz

    2008-03-01

    Detailed morphological analysis of pulmonary structures and tissue, provided by modern CT scanners, is of utmost importance as in the case of oncological applications both for diagnosis, treatment, and follow-up. In this case, a patient may go through several tomographic studies throughout a period of time originating volumetric sets of image data that must be appropriately registered in order to track suspicious radiological findings. The structures or regions of interest may change their position or shape in CT exams acquired at different moments, due to postural, physiologic or pathologic changes, so, the exams should be registered before any follow-up information can be extracted. Postural mismatching throughout time is practically impossible to avoid being particularly evident when imaging is performed at the limiting spatial resolution. In this paper, we propose a method for intra-patient registration of pulmonary CT studies, to assist in the management of the oncological pathology. Our method takes advantage of prior segmentation work. In the first step, the pulmonary segmentation is performed where trachea and main bronchi are identified. Then, the registration method proceeds with a longitudinal alignment based on morphological features of the lungs, such as the position of the carina, the pulmonary areas, the centers of mass and the pulmonary trans-axial principal axis. The final step corresponds to the trans-axial registration of the corresponding pulmonary masked regions. This is accomplished by a pairwise sectional registration process driven by an iterative search of the affine transformation parameters leading to optimal similarity metrics. Results with several cases of intra-patient, intra-modality registration, up to 7 time points, show that this method provides accurate registration which is needed for quantitative tracking of lesions and the development of image fusion strategies that may effectively assist the follow-up process.

  7. Volumetric optoacoustic monitoring of endovenous laser treatments

    Science.gov (United States)

    Fehm, Thomas F.; Deán-Ben, Xosé L.; Schaur, Peter; Sroka, Ronald; Razansky, Daniel

    2016-03-01

    Chronic venous insufficiency (CVI) is one of the most common medical conditions with reported prevalence estimates as high as 30% in the adult population. Although conservative management with compression therapy may improve the symptoms associated with CVI, healing often demands invasive procedures. Besides established surgical methods like vein stripping or bypassing, endovenous laser therapy (ELT) emerged as a promising novel treatment option during the last 15 years offering multiple advantages such as less pain and faster recovery. Much of the treatment success hereby depends on monitoring of the treatment progression using clinical imaging modalities such as Doppler ultrasound. The latter however do not provide sufficient contrast, spatial resolution and three-dimensional imaging capacity which is necessary for accurate online lesion assessment during treatment. As a consequence, incidence of recanalization, lack of vessel occlusion and collateral damage remains highly variable among patients. In this study, we examined the capacity of volumetric optoacoustic tomography (VOT) for real-time monitoring of ELT using an ex-vivo ox foot model. ELT was performed on subcutaneous veins while optoacoustic signals were acquired and reconstructed in real-time and at a spatial resolution in the order of 200μm. VOT images showed spatio-temporal maps of the lesion progression, characteristics of the vessel wall, and position of the ablation fiber's tip during the pull back. It was also possible to correlate the images with the temperature elevation measured in the area adjacent to the ablation spot. We conclude that VOT is a promising tool for providing online feedback during endovenous laser therapy.

  8. Pregnancy rates following timed embryo transfer with fresh or vitrified in vitro produced embryos in lactating dairy cows under heat stress conditions.

    Science.gov (United States)

    Al-Katanani, Y M; Drost, M; Monson, R L; Rutledge, J J; Krininger, C E; Block, J; Thatcher, W W; Hanse, P J

    2002-07-01

    Timed embryo transfer (TET) using in vitro produced (IVP) embryos without estrus detection can be used to reduce adverse effects of heat stress on fertility. One limitation is the poor survival of IVP embryos after cryopreservation. Objectives of this study were to confirm beneficial effects of TET on pregnancy rate during heat stress as compared to timed artificial insemination (TAI), and to determine if cryopreservation by vitrification could improve survival of IVP embryos transferred to dairy cattle under heat stress conditions. For vitrified embryos (TET-V), a three-step pre-equilibration procedure was used to vitrify excellent and good quality Day 7 IVP Holstein blastocysts. For fresh IVP embryos (TET-F), Holstein oocytes were matured and fertilized; resultant embryos were cultured in modified KSOM for 7 days using the same method as for production of vitrified embryos. Excellent and good quality blastocysts on Day 7 were transported to the cooperating dairy in a portable incubator. Nonpregnant, lactating Holsteins (n = 155) were treated with GnRH (100 microg, i.m., Day 0), followed 7 days later by prostaglandin F2alpha (PGF2alpha, 25 mg, i.m.) and GnRH (100 microg) on Day 9. Cows in the TAI treatment (n = 68) were inseminated the next day (Day 10) with semen from a single bull that also was used to produce embryos. Cows in the other treatments (n = 33 for TET-F; n = 54 for TET-V) received an embryo on Day 17 (i.e. Day 7 after anticipated ovulation and Day 8 after second GnRH treatment). The proportion of cows that responded to synchronization based on plasma progesterone concentrations on Day 10 and Day 17 was 67.7%. Pregnancy rate for all cows on Day 45 was higher (P cows responding to synchronization, pregnancy rate was also higher (P cows producing more milk had lower (P cows producing less milk. In conclusion, ET of fresh IVP embryos can improve pregnancy rate under heat stress conditions, but pregnancy rate following transfer of vitrified embryos was no

  9. Visualization and volumetric structures from MR images of the brain

    Energy Technology Data Exchange (ETDEWEB)

    Parvin, B.; Johnston, W.; Robertson, D.

    1994-03-01

    Pinta is a system for segmentation and visualization of anatomical structures obtained from serial sections reconstructed from magnetic resonance imaging. The system approaches the segmentation problem by assigning each volumetric region to an anatomical structure. This is accomplished by satisfying constraints at the pixel level, slice level, and volumetric level. Each slice is represented by an attributed graph, where nodes correspond to regions and links correspond to the relations between regions. These regions are obtained by grouping pixels based on similarity and proximity. The slice level attributed graphs are then coerced to form a volumetric attributed graph, where volumetric consistency can be verified. The main novelty of our approach is in the use of the volumetric graph to ensure consistency from symbolic representations obtained from individual slices. In this fashion, the system allows errors to be made at the slice level, yet removes them when the volumetric consistency cannot be verified. Once the segmentation is complete, the 3D surfaces of the brain can be constructed and visualized.

  10. Soft bilateral filtering volumetric shadows using cube shadow maps

    Science.gov (United States)

    Ali, Hatam H.; Sunar, Mohd Shahrizal; Kolivand, Hoshang

    2017-01-01

    Volumetric shadows often increase the realism of rendered scenes in computer graphics. Typical volumetric shadows techniques do not provide a smooth transition effect in real-time with conservation on crispness of boundaries. This research presents a new technique for generating high quality volumetric shadows by sampling and interpolation. Contrary to conventional ray marching method, which requires extensive time, this proposed technique adopts downsampling in calculating ray marching. Furthermore, light scattering is computed in High Dynamic Range buffer to generate tone mapping. The bilateral interpolation is used along a view rays to smooth transition of volumetric shadows with respect to preserving-edges. In addition, this technique applied a cube shadow map to create multiple shadows. The contribution of this technique isreducing the number of sample points in evaluating light scattering and then introducing bilateral interpolation to improve volumetric shadows. This contribution is done by removing the inherent deficiencies significantly in shadow maps. This technique allows obtaining soft marvelous volumetric shadows, having a good performance and high quality, which show its potential for interactive applications. PMID:28632740

  11. Volumetric and MGMT parameters in glioblastoma patients: Survival analysis

    Directory of Open Access Journals (Sweden)

    Iliadis Georgios

    2012-01-01

    Full Text Available Abstract Background In this study several tumor-related volumes were assessed by means of a computer-based application and a survival analysis was conducted to evaluate the prognostic significance of pre- and postoperative volumetric data in patients harboring glioblastomas. In addition, MGMT (O6-methylguanine methyltransferase related parameters were compared with those of volumetry in order to observe possible relevance of this molecule in tumor development. Methods We prospectively analyzed 65 patients suffering from glioblastoma (GBM who underwent radiotherapy with concomitant adjuvant temozolomide. For the purpose of volumetry T1 and T2-weighted magnetic resonance (MR sequences were used, acquired both pre- and postoperatively (pre-radiochemotherapy. The volumes measured on preoperative MR images were necrosis, enhancing tumor and edema (including the tumor and on postoperative ones, net-enhancing tumor. Age, sex, performance status (PS and type of operation were also included in the multivariate analysis. MGMT was assessed for promoter methylation with Multiplex Ligation-dependent Probe Amplification (MLPA, for RNA expression with real time PCR, and for protein expression with immunohistochemistry in a total of 44 cases with available histologic material. Results In the multivariate analysis a negative impact was shown for pre-radiochemotherapy net-enhancing tumor on the overall survival (OS (p = 0.023 and for preoperative necrosis on progression-free survival (PFS (p = 0.030. Furthermore, the multivariate analysis confirmed the importance of PS in PFS and OS of patients. MGMT promoter methylation was observed in 13/23 (43.5% evaluable tumors; complete methylation was observed in 3/13 methylated tumors only. High rate of MGMT protein positivity (> 20% positive neoplastic nuclei was inversely associated with pre-operative tumor necrosis (p = 0.021. Conclusions Our findings implicate that volumetric parameters may have a significant role in

  12. Toward a Philosophy and Theory of Volumetric Nonthermal Processing.

    Science.gov (United States)

    Sastry, Sudhir K

    2016-06-01

    Nonthermal processes for food preservation have been under intensive investigation for about the past quarter century, with varying degrees of success. We focus this discussion on two volumetrically acting nonthermal processes, high pressure processing (HPP) and pulsed electric fields (PEF), with emphasis on scientific understanding of each, and the research questions that need to be addressed for each to be more successful in the future. We discuss the character or "philosophy" of food preservation, with a question about the nature of the kill step(s), and the sensing challenges that need to be addressed. For HPP, key questions and needs center around whether its nonthermal effectiveness can be increased by increased pressures or pulsing, the theoretical treatment of rates of reaction as influenced by pressure, the assumption of uniform pressure distribution, and the need for (and difficulties involved in) in-situ measurement. For PEF, the questions include the rationale for pulsing, difficulties involved in continuous flow treatment chambers, the difference between electroporation theory and experimental observations, and the difficulties involved in in-situ measurement and monitoring of electric field distribution.

  13. Optical artefact characterization and correction in volumetric scintillation dosimetry

    Science.gov (United States)

    Robertson, Daniel; Hui, Cheukkai; Archambault, Louis; Mohan, Radhe; Beddar, Sam

    2014-01-01

    The goals of this study were (1) to characterize the optical artefacts affecting measurement accuracy in a volumetric liquid scintillator detector, and (2) to develop methods to correct for these artefacts. The optical artefacts addressed were photon scattering, refraction, camera perspective, vignetting, lens distortion, the lens point spread function, stray radiation, and noise in the camera. These artefacts were evaluated by theoretical and experimental means, and specific correction strategies were developed for each artefact. The effectiveness of the correction methods was evaluated by comparing raw and corrected images of the scintillation light from proton pencil beams against validated Monte Carlo calculations. Blurring due to the lens and refraction at the scintillator tank-air interface were found to have the largest effect on the measured light distribution, and lens aberrations and vignetting were important primarily at the image edges. Photon scatter in the scintillator was not found to be a significant source of artefacts. The correction methods effectively mitigated the artefacts, increasing the average gamma analysis pass rate from 66% to 98% for gamma criteria of 2% dose difference and 2 mm distance to agreement. We conclude that optical artefacts cause clinically meaningful errors in the measured light distribution, and we have demonstrated effective strategies for correcting these optical artefacts.

  14. Femoral head osteonecrosis: Volumetric MRI assessment and outcome

    Energy Technology Data Exchange (ETDEWEB)

    Bassounas, Athanasios E. [Department of Medical Physics, School of Medicine, University of Ioannina, GR 451 10 Ioannina (Greece); Karantanas, Apostolos H. [Department of Radiology, School of Medicine, University of Crete, Heraklion, GR 711 10 (Greece); Fotiadis, Dimitrios I. [Unit of Medical Technology and Intelligent Information Systems, Department of Computer Science, University of Ioannina and Biomedical Research Institute-FORTH, GR 451 10 Ioannina (Greece); Malizos, Konstantinos N. [Orthopaedic Department, Medical School, University of Thessalia, GR 412 22 Larissa (Greece)]. E-mail: kmalizos@otenet.gr

    2007-07-15

    Effective treatment of femoral head osteonecrosis (FHON) requires early diagnosis and accurate assessment of the disease severity. The ability to predict in the early stages the risk of collapse is important for selecting a joint salvage procedure. The aim of the present study was to evaluate the outcome in patients treated with vascularized fibular grafts in relation to preoperative MR imaging volumetry. We studied 58 patients (87 hips) with FHON. A semi-automated octant-based lesion measurement method, previously described, was performed on the T1-w MR images. The mean time of postoperative follow-up was 7.8 years. Sixty-three hips were successful and 24 failed and converted to total hip arthroplasty within a period of 2-4 years after the initial operation. The rate of failures for hips of male patients was higher than in female patients. The mean lesion size was 28% of the sphere equivalent of the femoral head, 24 {+-} 12% for the successful hips and 37 {+-} 9% for the failed (p < 0.001). The most affected octants were antero-supero-medial (58 {+-} 26%) and postero-supero-medial (54 {+-} 31%). All but postero-infero-medial and postero-infero-lateral octants, showed statistically significant differences in the lesion size between patients with successful and failed hips. In conclusion, the volumetric analysis of preoperative MRI provides useful information with regard to a successful outcome in patients treated with vascularized fibular grafts.

  15. Gas sorption and the consequent volumetric and permeability change of coal

    Science.gov (United States)

    Lin, Wenjuan

    Experimental and numerical investigations of gas sorption on coal, and the subsequent volumetric and permeability changes of the coal were conducted. The goals of the study were to investigate the magnitude of permeability change caused by gas sorption, and develop an algorithm to simulate numerically gas sorption and sorption-induced permeability change. The amount of gas sorption and the subsequent volumetric and permeability change of coal samples as a function of pore pressure and injection gas composition were measured in the laboratory. A constant effective confining pressure (difference between the confining pressure and pore pressure) was maintained in the process of the experiments; therefore, the role of effective stress on permeability was eliminated. Several gases, including pure CO2, pure N2, and binary mixtures of CO2 and N2 of various compositions were used as the injection gas. The coal sample was first allowed to adsorb an injection gas fully at a particular pressure. The total amount (moles) of adsorption was calculated based on a volumetric method. After adsorption equilibrium was reached, gas samples were taken from the equilibrium gaseous phase and analyzed afterwards. The composition of the gaseous phase prior to and after the adsorption was used to calculate the composition of the adsorbed phase based on material balance. Permeability of the sample was then measured by flowing the injection gas through the core at varying pressure gradient or varying flow rate, and an average permeability was obtained based on Darcy's law for compressible systems. The change of the total volume of the core was monitored and recorded in the whole process of the experiment. Volumetric strain was thereby calculated. Experimental results showed that the greater the pressure the greater the amount of adsorption for all tested gases. At the same pressure, the amount of adsorption was greater for CO2 than N2. For the binary mixtures, the greater the fraction of CO 2

  16. Optimal spacing within a tubed, volumetric, cavity receiver suitable for modular molten salt solar towers

    Science.gov (United States)

    Turner, Peter

    2016-05-01

    A 2-dimensional radiation analysis has been developed to analyse the radiative efficiency of an arrangement of heat transfer tubes distributed in layers but spaced apart to form a tubed, volumetric receiver. Such an arrangement could be suitable for incorporation into a cavity receiver. Much of the benefit of this volumetric approach is gained after using 5 layers although improvements do continue with further layers. The radiation analysis splits each tube into multiple segments in which each segment surface can absorb, reflect and radiate rays depending on its surface temperature. An iterative technique is used to calculate appropriate temperatures depending on the distribution of the net energy absorbed and assuming that the cool heat transfer fluid (molten salt) starts at the front layer and flows back through successive layers to the rear of the cavity. Modelling the finite diameter of each layer of tubes increases the ability of a layer to block radiation scattered at acute angles and this effect is shown to reduce radiation losses by nearly 25% compared to the earlier 1-d analysis. Optimum efficient designs tend to occur when the blockage factor is 0.2 plus the inverse of the number of tube layers. It is beneficial if the distance between successive layers is ≥ 2 times the diameter of individual tubes and in this situation, if the incoming radiation is spread over a range of angles, the performance is insensitive to the degree of any tube positional offset or stagger between layers.

  17. Numerical Validation and Comparison of Three Solar Wind Heating Methods by the SIP-CESE MHD Model

    Institute of Scientific and Technical Information of China (English)

    YANG Li-Ping; FENG Xue-Shang; XIANG Chang-Qing; JIANG Chao-Wei

    2011-01-01

    We conduct simulations using the three-dimensional(3D) solar-interplanetary conservation element/solution element(SIP-CESE) maguetohydrodynamic(MHD) model and magnetogram data from a Carrington rotation (CR) 1897 to compare the three commonly used heating methods, I.e. The Wentzel-Kramers-Brillouin(WKB)Alfvén wave heating method, the turbulence heating method and the volumetric heating method. Our results show that all three heating models can basically reproduce the bimodal structure of the solar wind observed near the solar minimum. The results also demonstrate that the major acceleration interval terminates about 4Rs for the turbulence heating method and 1ORs for both the WKB Alfvén wave heating method and the volumetric heating method. The turbulence heating and the volumetric heating methods can capture the observed changing trends by the WIND satellite, while the WKB Alfvén wave heating method does not.

  18. Determination of convective diffusion heat/mass transfer rates to burner rig test targets comparable in size to cross-stream jet diameter

    Science.gov (United States)

    Gokoglu, S. A.; Santoro, G. J.

    1985-01-01

    Two sets of experiments have been performed to be able to predict the convective diffusion heat/mass transfer rates to a cylindrical target whose height and diameter are comparable to, but less than, the diameter of the circular cross-stream jet, thereby simulating the same geometric configuration as a typical burner rig test specimen located in the cross-stream of the combustor exit nozzle. The first set exploits the naphthalene sublimation technique to determine the heat/mass transfer coefficient under isothermal conditions for various flow rates (Reynolds numbers). The second set, conducted at various combustion temperatures and Reynolds numbers, utilized the temperature variation along the surface of the above-mentioned target under steady-state conditions to estimate the effect of cooling (dilution) due to the entrainment of stagnant room temperature air. The experimental information obtained is used to predict high temperature, high velocity corrosive salt vapor deposition rates in burner rigs on collectors that are geometrically the same. The agreement with preliminary data obtained from Na2SO4 vapor deposition experiments is found to be excellent.

  19. Enhancement of Pool Boiling Heat Transfer Using Aligned Silicon Nanowire Arrays.

    Science.gov (United States)

    Shim, Dong Il; Choi, Geehong; Lee, Namkyu; Kim, Taehwan; Kim, Beom Seok; Cho, Hyung Hee

    2017-05-24

    Enhancing the critical heat flux (CHF), which is the capacity of heat dissipation, is important to secure high stability in two-phase cooling systems. Coolant supply to a dry hot spot is a major mechanism to prevent surface burn-out for enhancing the CHF. Here, we demonstrate a more ready supply of coolant using aligned silicon nanowires (A-SiNWs), with a high aspect ratio (>10) compared to that of conventional random silicon nanowires (R-SiNWs), which have a disordered arrangement, for additional CHF improvement. We propose the volumetric wicking rate, which represents the coolant supply properties by considering both the liquid supply velocity and the amount of coolant (i.e., wicking coefficient and wetted volume, respectively). Through experimental approaches, we confirm that the CHF is enhanced as the volumetric wicking rate is increased. In good agreement with the fabrication hypothesis, A-SiNWs demonstrate higher coolant supply abilities than those of R-SiNWs. The longest (7 μm) A-SiNWs have the highest volumetric wicking rate (25.11 × 10(-3) mm(3)/s) and increase the CHF to 245.6 W/cm(2), which is the highest value obtained using nanowires among reported data (178 and 26% enhanced vs unmodulated plain surface and R-SiNWs, respectively). These well-aligned SiNWs can increase the CHF significantly with efficient coolant supply, and it can ensure high stability in extremely high thermal load systems. Moreover, our study provides nanoscale interfacial design strategies for further improvement of heat dissipation.

  20. Efficient ground-state cooling of an ion in a large room-temperature linear Paul trap with a sub-Hertz heating rate

    DEFF Research Database (Denmark)

    Poulsen, Gregers; Miroshnychenko, Yevhen; Drewsen, Michael

    2012-01-01

    We demonstrate efficient resolved sideband laser cooling (99±1% ground-state population) of a single 40Ca+ ion in a large linear Paul trap (electrode spacing of 7 mm) operated at an rf drive frequency of just 3.7 MHz. For ion oscillation frequencies in the range 280–585 kHz, heating rates below...... or about one motional quantum per second have been measured at room temperature. The results, obtained under these unconventional sideband cooling conditions, pave the way for a range of new types of cold ion experiments, including spectroscopy of molecular ions as well as ultracold chemistry....

  1. Design and Operation of a Cryogenic Nitrogen Pulsating Heat Pipe

    Science.gov (United States)

    Diego Fonseca, Luis; Miller, Franklin; Pfotenhauer, John

    2015-12-01

    We report the design, experimental setup and successful test results using an innovative passive cooling system called a “Pulsating Heat Pipe” (PHP) operating at temperatures ranging from 77 K to 80 K and using nitrogen as the working fluid. PHPs, which transfer heat by two phase flow mechanisms through a closed loop tubing have the advantage that no electrical pumps are needed to drive the fluid flow. In addition, PHPs have an advantage over copper straps and thermal conductors since they are lighter in weight, exhibit lower temperature gradients and have higher heat transfer rates. PHPs consist of an evaporator section, thermally anchored to a solid, where heat is received at the saturation temperature where the liquid portion of the two-phase flow evaporates, and a condenser where heat is rejected at the saturation temperature where the vapor is condensed. The condenser section in our experiment has been thermally interfaced to a CT cryocooler from SunPower that has a cooling capacity of 10 W at 77 K. Alternating regions of liquid slugs and small vapor plugs fill the capillary tubing, with the vapor regions contracting in the condenser section and expanding in the evaporator section due to an electric heater that will generate heat loads up to 10 W. This volumetric expansion and contraction provides the oscillatory flow of the fluid throughout the capillary tubing thereby transferring heat from one end to the other. The thermal performance and temperature characteristics of the PHP will be correlated as a function of average condenser temperature, PHP fill liquid ratio, and evaporator heat load. The experimental data show that the heat transfer between the evaporator and condenser sections can produce an effective thermal conductivity up to 35000 W/m-K at a 3.5 W heat load.

  2. Investigation of the heating rate dependency associated with the loss of crystalline structure in sucrose, glucose, and fructose using a thermal analysis approach (part I).

    Science.gov (United States)

    Lee, Joo Won; Thomas, Leonard C; Schmidt, Shelly J

    2011-01-26

    Thermodynamic melting occurs at a single, time-independent temperature with a constant enthalpy value. However, substantial variation in the melting parameters (T(m onset), T(m peak), and ΔH) for sucrose, glucose, and fructose has been reported in the literature. Although a number of explanations have been put forth, they do not completely account for the observed variation. Thus, this research was performed to elucidate the fundamental mechanism underlying the loss of crystalline structure in the sugars using both thermal (Part I) and chemical (Part II) analysis approaches. A strong heating rate dependency observed in the melting parameters for the sugars implies the occurrence of a kinetic process during the loss of crystalline structure. The difference in heat capacity and modulated heat flow amplitude in the stepwise quasi-isothermal modulated differential scanning calorimetry experiments for the sugars compared to indium and mannitol (thermodynamic melting comparison materials) strongly suggests thermal decomposition as the kinetic process responsible for the loss of crystalline structure, which is the critical difference between our conclusion and others. We propose the term "apparent melting" to distinguish the loss of crystalline structure due to a kinetic process, such as thermal decomposition, from thermodynamic melting.

  3. High-rate continuous hydrogen production by Thermoanaerobacterium thermosaccharolyticum PSU-2 immobilized on heat-pretreated methanogenic granules

    DEFF Research Database (Denmark)

    O-Thong, Sompong; Prasertsan, P.; Karakashev, Dimitar Borisov;

    2008-01-01

    as carrier to immobilize T. thermosaccharolyticum strain PSU-2 in UASB reactor operated at a hydraulic retention time (HRT) ranging from 0.75 to 24h and corresponding sucrose loading rate from 58.5 to 2.4 mmol sucrose l(-1)h(-1). In comparison with hydrogen production rate of 12.1 mmol H(2)l(-1)h(-1......) obtained by carrier-free reactor upflow anaerobic (UA) system, a greatly improved hydrogen production rate up to 152 mmol H(2)l(-1)h(-1) was demonstrated by the granular cells in UASB system. The biofilm of T. thermosaccharolyticum strain PSU-2 developed on treated methanogenic granules in UASB reactor...... substantially enhanced biomass retention (3 times), and production of hydrogen (12 times) compared to carrier-free reactor. It appears to be the most preferred process for highly efficient dark fermentative hydrogen production from sugar containing wastewater under thermophilic conditions. (C) 2008...

  4. Volumetric Properties of the Mixture Trichloromethane CHCl3 + C5H10O Pentan-3-one (VMSD1212, LB4605_V)

    Science.gov (United States)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume C 'Binary Liquid Systems of Nonelectrolytes III' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Volumetric Properties of the Mixture Trichloromethane CHCl3 + C5H10O Pentan-3-one (VMSD1212, LB4605_V)' providing data by calculation of molar excess volume from low-pressure density measurements at variable mole fraction and constant temperature.

  5. Volumetric Properties of the Mixture Trichloromethane CHCl3 + C5H10O Pentan-3-one (VMSD1111, LB4603_V)

    Science.gov (United States)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume C 'Binary Liquid Systems of Nonelectrolytes III' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Volumetric Properties of the Mixture Trichloromethane CHCl3 + C5H10O Pentan-3-one (VMSD1111, LB4603_V)' providing data from direct low-pressure measurement of mass density at variable mole fraction and constant temperature, in the single-phase region(s).

  6. Volumetric Properties of the Mixture Trichloromethane CHCl3 + C6H14O Hexan-1-ol (VMSD1212, LB5052_V)

    Science.gov (United States)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume C 'Binary Liquid Systems of Nonelectrolytes III' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Volumetric Properties of the Mixture Trichloromethane CHCl3 + C6H14O Hexan-1-ol (VMSD1212, LB5052_V)' providing data by calculation of molar excess volume from low-pressure density measurements at variable mole fraction and constant temperature.

  7. Volumetric Properties of the Mixture Trichloromethane CHCl3 + C4H10O Butan-1-ol (VMSD1511, LB5192_V)

    Science.gov (United States)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume C 'Binary Liquid Systems of Nonelectrolytes III' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Volumetric Properties of the Mixture Trichloromethane CHCl3 + C4H10O Butan-1-ol (VMSD1511, LB5192_V)' providing data from direct measurement of low-pressure thermodynamic speed of sound at variable mole fraction and constant temperature, in the single-phase region(s).

  8. Volumetric Properties of the Mixture Trichloromethane CHCl3 + C3H8O Propan-1-ol (VMSD1212, LB5190_V)

    Science.gov (United States)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume A 'Binary Liquid Systems of Nonelectrolytes I' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Volumetric Properties of the Mixture Trichloromethane CHCl3 + C3H8O Propan-1-ol (VMSD1212, LB5190_V)' providing data by calculation of molar excess volume from low-pressure density measurements at variable mole fraction and constant temperature.

  9. Volumetric Properties of the Mixture Trichloromethane CHCl3 + C6H14O Hexan-1-ol (VMSD1511, LB5055_V)

    Science.gov (United States)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume C 'Binary Liquid Systems of Nonelectrolytes III' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Volumetric Properties of the Mixture Trichloromethane CHCl3 + C6H14O Hexan-1-ol (VMSD1511, LB5055_V)' providing data from direct measurement of low-pressure thermodynamic speed of sound at variable mole fraction and constant temperature, in the single-phase region(s).

  10. Volumetric Properties of the Mixture Trichloromethane CHCl3 + C7H16O Heptan-1-ol (VMSD1111, LB5050_V)

    Science.gov (United States)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume A 'Binary Liquid Systems of Nonelectrolytes I' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Volumetric Properties of the Mixture Trichloromethane CHCl3 + C7H16O Heptan-1-ol (VMSD1111, LB5050_V)' providing data from direct low-pressure measurement of mass density at variable mole fraction and constant temperature, in the single-phase region(s).

  11. Volumetric Properties of the Mixture Trichloromethane CHCl3 + C3H8O Propan-1-ol (VMSD1412, LB5193_V)

    Science.gov (United States)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume A 'Binary Liquid Systems of Nonelectrolytes I' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Volumetric Properties of the Mixture Trichloromethane CHCl3 + C3H8O Propan-1-ol (VMSD1412, LB5193_V)' providing data by calculation of isentropic compressibility from low-pressure density and thermodynamic speed of sound data at variable mole fraction and constant temperature, in the single-phase region(s).

  12. Volumetric Properties of the Mixture Trichloromethane CHCl3 + C4H8O2 1,4-Dioxane (VMSD1211, LB3413_V)

    Science.gov (United States)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume C 'Binary Liquid Systems of Nonelectrolytes III' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Volumetric Properties of the Mixture Trichloromethane CHCl3 + C4H8O2 1,4-Dioxane (VMSD1211, LB3413_V)' providing data from direct low-pressure dilatometric measurement of molar excess volume at variable mole fraction and constant temperature.

  13. Volumetric Properties of the Mixture Trichloromethane CHCl3 + C3H7NO N-Methylethanamide (VMSD1211, LB4401_V)

    Science.gov (United States)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume C 'Binary Liquid Systems of Nonelectrolytes III' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Volumetric Properties of the Mixture Trichloromethane CHCl3 + C3H7NO N-Methylethanamide (VMSD1211, LB4401_V)' providing data from direct low-pressure dilatometric measurement of molar excess volume at variable mole fraction and constant temperature.

  14. Volumetric Properties of the Mixture Trichloromethane CHCl3 + C4H10O Butan-1-ol (VMSD1111, LB5188_V)

    Science.gov (United States)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume C 'Binary Liquid Systems of Nonelectrolytes III' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Volumetric Properties of the Mixture Trichloromethane CHCl3 + C4H10O Butan-1-ol (VMSD1111, LB5188_V)' providing data from direct low-pressure measurement of mass density at variable mole fraction and constant temperature, in the single-phase region(s).

  15. Volumetric Properties of the Mixture Trichloromethane CHCl3 + C3H6O2 1,3-Dioxolane (VMSD1212, LB3578_V)

    Science.gov (United States)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume C 'Binary Liquid Systems of Nonelectrolytes III' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Volumetric Properties of the Mixture Trichloromethane CHCl3 + C3H6O2 1,3-Dioxolane (VMSD1212, LB3578_V)' providing data by calculation of molar excess volume from low-pressure density measurements at variable mole fraction and constant temperature.

  16. Volumetric Properties of the Mixture Trichloromethane CHCl3 + C3H6O Propan-2-one (VMSD1211, LB3410_V)

    Science.gov (United States)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume C 'Binary Liquid Systems of Nonelectrolytes III' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Volumetric Properties of the Mixture Trichloromethane CHCl3 + C3H6O Propan-2-one (VMSD1211, LB3410_V)' providing data from direct low-pressure dilatometric measurement of molar excess volume at variable mole fraction and constant temperature.

  17. Volumetric Properties of the Mixture Trichloromethane CHCl3 + C4H8O2 Ethyl ethanoate (VMSD1212, LB4146_V)

    Science.gov (United States)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume C 'Binary Liquid Systems of Nonelectrolytes III' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Volumetric Properties of the Mixture Trichloromethane CHCl3 + C4H8O2 Ethyl ethanoate (VMSD1212, LB4146_V)' providing data by calculation of molar excess volume from low-pressure density measurements at variable mole fraction and constant temperature.

  18. Volumetric Properties of the Mixture Trichloromethane CHCl3 + C6H12O 4-Methylpentan-2-one (VMSD1212, LB4040_V)

    Science.gov (United States)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume C 'Binary Liquid Systems of Nonelectrolytes III' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Volumetric Properties of the Mixture Trichloromethane CHCl3 + C6H12O 4-Methylpentan-2-one (VMSD1212, LB4040_V)' providing data by calculation of molar excess volume from low-pressure density measurements at variable mole fraction and constant temperature.

  19. Volumetric Properties of the Mixture Trichloromethane CHCl3 + C2H4Cl2 1,2-Dichloroethane (VMSD1212, LB4575_V)

    Science.gov (United States)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume A 'Binary Liquid Systems of Nonelectrolytes I' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Volumetric Properties of the Mixture Trichloromethane CHCl3 + C2H4Cl2 1,2-Dichloroethane (VMSD1212, LB4575_V)' providing data by calculation of molar excess volume from low-pressure density measurements at variable mole fraction and constant temperature.

  20. Volumetric Properties of the Mixture Trichloromethane CHCl3 + C7H16O Heptan-1-ol (VMSD1212, LB5053_V)

    Science.gov (United States)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume A 'Binary Liquid Systems of Nonelectrolytes I' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Volumetric Properties of the Mixture Trichloromethane CHCl3 + C7H16O Heptan-1-ol (VMSD1212, LB5053_V)' providing data by calculation of molar excess volume from low-pressure density measurements at variable mole fraction and constant temperature.