Localised drug release using MRI-controlled focused ultrasound hyperthermia.

PubMed

Staruch, Robert; Chopra, Rajiv; Hynynen, Kullervo

2011-01-01

Thermosensitive liposomes provide a mechanism for triggering the local release of anticancer drugs, but this technology requires precise temperature control in targeted regions with minimal heating of surrounding tissue. The objective of this study was to evaluate the feasibility of using MRI-controlled focused ultrasound (FUS) and thermosensitive liposomes to achieve thermally mediated localised drug delivery in vivo. Results are reported from ten rabbits, where a FUS beam was scanned in a circular trajectory to heat 10-15 mm diameter regions in normal thigh to 43°C for 20-30 min. MRI thermometry was used for closed-loop feedback control to achieve temporally and spatially uniform heating. Lyso-thermosensitive liposomal doxorubicin was infused intravenously during hyperthermia. Unabsorbed liposomes were flushed from the vasculature by saline perfusion 2 h later, and tissue samples were harvested from heated and unheated thigh regions. The fluorescence intensity of the homogenised samples was used to calculate the concentration of doxorubicin in tissue. Closed-loop control of FUS heating using MRI thermometry achieved temperature distributions with mean, T90 and T10 of 42.9°C, 41.0°C and 44.8°C, respectively, over a period of 20 min. Doxorubicin concentrations were significantly higher in tissues sampled from heated than unheated regions of normal thigh muscle (8.3 versus 0.5 ng/mg, mean per-animal difference = 7.8 ng/mg, P < 0.05, Wilcoxon matched pairs signed rank test). The results show the potential of MRI-controlled focused ultrasound hyperthermia for enhanced local drug delivery with temperature-sensitive drug carriers.

Numerical Simulation of Temperature Sensor Self-Heating Effects in Gaseous and Liquid Hydrogen Under Cryogenic Conditions

NASA Astrophysics Data System (ADS)

Langebach, R.; Haberstroh, Ch.

2010-04-01

In this paper a numerical investigation is presented that characterizes the free convective flow field and the resulting heat transfer mechanisms for a resistance temperature sensor in liquid and gaseous hydrogen at various cryogenic conditions. Motivation for this is the detection of stratification effects e.g. inside a liquid hydrogen storage vessel. In this case, the local temperature measurement in still resting fluid requires a very high standard of precision despite an extremely poor thermal anchoring of the sensor. Due to electrical power dissipation a certain amount of heat has to be transferred from sensor to fluid. This can cause relevant measurement errors due to a slightly elevated sensor temperature. A commercial CFD code was employed to calculate the heat and mass transfer around the typical sensor geometry. The results were compared with existing heat transfer correlations from the literature. As a result the magnitude of averaged heat transfer coefficients and sensor over-heating as a function of power dissipation are given in figures. From the gained numerical results a new correlation for the averaged Nusselt Number is presented that represents very low Rayleigh Number flows. The correlation can be used to estimate sensor self-heating effects in similar situations.

Machine for preparing phosphors for the fluorimetric determination of uranium

USGS Publications Warehouse

Stevens, R.E.; Wood, W.H.; Goetz, K.G.; Horr, C.A.

1956-01-01

The time saved by use of a machine for preparing many phosphors at one time increases the rate of productivity of the fluorimetric method for determining uranium. The machine prepares 18 phosphors at a time and eliminates the tedious and time-consuming step of preparing them by hand, while improving the precision of the method in some localities. The machine consists of a ring burner over which the platinum dishes, containing uranium and flux, are rotated. By placing the machine in an inclined position the molten flux comes into contact with all surfaces within th dish as the dishes rotate over the flame. Precision is improved because the heating and cooling conditions are the same for each of the 18 phosphors in one run as well as for successive runs.

Enhanced green fluorescent protein in optofluidic Fabry-Perot microcavity to detect laser induced temperature changes in a bacterial culture

NASA Astrophysics Data System (ADS)

Lahoz, F.; Martín, I. R.; Walo, D.; Freire, R.; Gil-Rostra, J.; Yubero, F.; Gonzalez-Elipe, A. R.

2017-09-01

Thermal therapy using laser sources can be used in combination with other cancer therapies to eliminate tumors. However, high precision temperature control is required to avoid damage in healthy surrounding tissues. Therefore, in order to detect laser induced temperature changes, we have used the fluorescence signal of the enhanced Green Fluorescent Protein (eGFP) over-expressed in an E. coli bacterial culture. For that purpose, the bacteria expressing eGFP are injected in a Fabry-Perot (FP) optofluidic planar microcavity. In order to locally heat the bacterial culture, external infrared or ultraviolet lasers were used. Shifts in the wavelengths of the resonant FP modes are used to determine the temperature increase as a function of the heating laser pump power. Laser induced local temperature increments up to 6-7 °C were measured. These results show a relatively easy way to measure laser induced local temperature changes using a FP microcavity and using eGFP as a molecular probe instead of external nanoparticles, which could damage/alter the cell. Therefore, we believe that this approach can be of interest for the study of thermal effects in laser induced thermal therapies.

Multiple-objective optimization in precision laser cutting of different thermoplastics

NASA Astrophysics Data System (ADS)

Tamrin, K. F.; Nukman, Y.; Choudhury, I. A.; Shirley, S.

2015-04-01

Thermoplastics are increasingly being used in biomedical, automotive and electronics industries due to their excellent physical and chemical properties. Due to the localized and non-contact process, use of lasers for cutting could result in precise cut with small heat-affected zone (HAZ). Precision laser cutting involving various materials is important in high-volume manufacturing processes to minimize operational cost, error reduction and improve product quality. This study uses grey relational analysis to determine a single optimized set of cutting parameters for three different thermoplastics. The set of the optimized processing parameters is determined based on the highest relational grade and was found at low laser power (200 W), high cutting speed (0.4 m/min) and low compressed air pressure (2.5 bar). The result matches with the objective set in the present study. Analysis of variance (ANOVA) is then carried out to ascertain the relative influence of process parameters on the cutting characteristics. It was found that the laser power has dominant effect on HAZ for all thermoplastics.

A FRET-guided, NIR-responsive bubble-generating liposomal system for in vivo targeted therapy with spatially and temporally precise controlled release.

PubMed

Chuang, Er-Yuan; Lin, Chia-Chen; Chen, Ko-Jie; Wan, De-Hui; Lin, Kun-Ju; Ho, Yi-Cheng; Lin, Po-Yen; Sung, Hsing-Wen

2016-07-01

The nonspecific distribution of therapeutic agents and nontargeted heating commonly produce undesirable side effects during cancer treatment since the optimal timing of triggering the carrier systems is unknown. This work proposes a multifunctional liposomal system that can intracellularly and simultaneously deliver the therapeutic drug doxorubicin (DOX), heat, and a bubble-generating agent (ammonium bicarbonate, ABC) into targeted tumor cells to have a cytotoxic effect. Gold nanocages that are encapsulated in liposomes effectively convert near-infrared light irradiation into localized heat, which causes the decomposition of ABC and generates CO2 bubbles, rapidly triggering the release of DOX. Additionally, a hybridized Mucin-1 aptamer is conjugated on the surface of the test liposomes, which then function as a recognition probe to enhance the uptake of those liposomes by cells, and as a molecular beacon to signal when the internalized particles have been maximized, which is the optimal time for photothermally triggering the release of the drug following the systemic administration of the liposomes. Empirical results reveal that this combined treatment effectively controls targeted drug release in a spatially and temporally precise fashion and so significantly increases the potency of the drug while minimizing unwanted side effects, making it a promising treatment for cancer. Copyright © 2016 Elsevier Ltd. All rights reserved.

Ultrapulse welding: A new joining technique. [for automotive industry

NASA Technical Reports Server (NTRS)

Anderson, D. G.

1972-01-01

The ultrapulse process is a resistance welding process that utilizes unidirectional current of high magnitude for a very short time with a precisely controlled dynamic force pulse. Peak currents of up to 220,000 amperes for two to ten milliseconds are used with synchronized force pulses of up to nine thousand pounds. The welding current passing through the relatively high resistance of the interface between the parts that are being joined results in highly localized heating. Described is the UPW process as it applies to the automotive industry.

Engineering Localized Surface Plasmon Interactions in Gold by Silicon Nanowire for Enhanced Heating and Photocatalysis

DOE PAGES

Agarwal, Daksh; Aspetti, Carlos O.; Cargnello, Matteo; ...

2017-02-06

The field of plasmonics has attracted considerable attention in recent years because of potential applications in various fields such as nanophotonics, photovoltaics, energy conversion, catalysis, and therapeutics. It is becoming increasing clear that intrinsic high losses associated with plasmons can be utilized to create new device concepts to harvest the generated heat. It is therefore important to design cavities, which can harvest optical excitations efficiently to generate heat. In this paper, we report a highly engineered nanowire cavity, which utilizes a high dielectric silicon core with a thin plasmonic film (Au) to create an effective metallic cavity to strongly confinemore » light, which when coupled with localized surface plasmons in the nanoparticles of the thin metal film produces exceptionally high temperatures upon laser irradiation. Raman spectroscopy of the silicon core enables precise measurements of the cavity temperature, which can reach values as high as 1000 K. The same Si–Au cavity with enhanced plasmonic activity when coupled with TiO 2 nanorods increases the hydrogen production rate by ~40% compared to similar Au–TiO 2 system without Si core, in ethanol photoreforming reactions. Finally, these highly engineered thermoplasmonic devices, which integrate three different cavity concepts (high refractive index core, metallo-dielectric cavity, and localized surface plasmons) along with the ease of fabrication demonstrate a possible pathway for designing optimized plasmonic devices with applications in energy conversion and catalysis.« less

Engineering Localized Surface Plasmon Interactions in Gold by Silicon Nanowire for Enhanced Heating and Photocatalysis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Agarwal, Daksh; Aspetti, Carlos O.; Cargnello, Matteo

The field of plasmonics has attracted considerable attention in recent years because of potential applications in various fields such as nanophotonics, photovoltaics, energy conversion, catalysis, and therapeutics. It is becoming increasing clear that intrinsic high losses associated with plasmons can be utilized to create new device concepts to harvest the generated heat. It is therefore important to design cavities, which can harvest optical excitations efficiently to generate heat. In this paper, we report a highly engineered nanowire cavity, which utilizes a high dielectric silicon core with a thin plasmonic film (Au) to create an effective metallic cavity to strongly confinemore » light, which when coupled with localized surface plasmons in the nanoparticles of the thin metal film produces exceptionally high temperatures upon laser irradiation. Raman spectroscopy of the silicon core enables precise measurements of the cavity temperature, which can reach values as high as 1000 K. The same Si–Au cavity with enhanced plasmonic activity when coupled with TiO 2 nanorods increases the hydrogen production rate by ~40% compared to similar Au–TiO 2 system without Si core, in ethanol photoreforming reactions. Finally, these highly engineered thermoplasmonic devices, which integrate three different cavity concepts (high refractive index core, metallo-dielectric cavity, and localized surface plasmons) along with the ease of fabrication demonstrate a possible pathway for designing optimized plasmonic devices with applications in energy conversion and catalysis.« less

Thermoelectric technique to precisely control hyperthermic exposures of human whole blood.

PubMed

DuBose, D A; Langevin, R C; Morehouse, D H

1996-12-01

The need in military research to avoid exposing humans to harsh environments and reduce animal use requires the development of in vitro models for the study of hyperthermic injury. A thermoelectric module (TEM) system was employed to heat human whole blood (HWB) in a manner similar to that experienced by heat-stroked rats. This system precisely and accurately replicated mild, moderate, and extreme heat-stress exposures. Temperature changes could be monitored without the introduction of a test sample thermistor, which reduced contamination problems. HWB with hematocrits of 45 or 50% had similar heating curves, indicating that the system compensated for differences in sample character. The unit's size permitted its containment within a standard carbon dioxide incubator to further control sample environment. These results indicate that the TEM system can precisely control temperature change in this heat stress in vitro model employing HWB. Information obtained from such a model could contribute to military preparedness.

40 CFR 63.14 - Incorporations by reference.

Code of Federal Regulations, 2010 CFR

2010-07-01

..., Heat of Combustion of Hydrocarbon Fuels by Bomb Calorimeter (High-Precision Method), IBR approved for... for Heat of Combustion of Liquid Hydrocarbon Fuels by Bomb Calorimeter (Precision Method), IBR... Oxygen Bomb Combustion/Atomic Absorption Method,1 IBR approved for table 6 to subpart DDDDD of this part...

Contributions to urban heat island on the local neighborhood scale

NASA Astrophysics Data System (ADS)

Hertel, Daniel; Schlink, Uwe

2017-04-01

Already today around half of the global population is living in urban regions and recent studies expect a further increase until mid-21st century. Therefore, especially in the context of climate change, an increasing amount of urban inhabitants are affected by urban climate and air quality. One special characteristic of urban climate is the urban heat island (UHI) effect, where urbanized regions are warmer than the rural surroundings. With respect to climate change and the growing urbanization it is obvious that the UHI effect will tend to be intensified. To keep our cities worth living, it is necessary to think about adaptation and mitigation strategies which refer to both, climate protection as well as utilization of chances resulting from climate changes. One step to a more precisely adaptation, particularly on the neighborhood scale, is an improved understanding of the magnitude of bio geophysical processes (e.g.: radiation balance, convection efficiency, evapotranspiration, storage heat, anthropogenic heat etc.), which contribute to the urban warming. Considering that UHI can be expressed as temperature difference ΔT between urban and rural areas, we can interpret these processes as how they would change temperature, because of energy redistribution, from a rural area to an urbanized region. Up to now on the local scale there is a knowledge gap about these processes. The mentioned processes are parts of a surface energy balance (based on the work of Zhao et al., 2014). That means they refer to the surface UHI effect and not to the canopy layer UHI effect. Assuming that the urban region is a volume with the top at the height of the canopy layer, we can approximately identify the surface UHI effect as the canopy layer UHI effect since the information comes from both the surface and the atmosphere inside. This assumption is not valid for Zhao's approach because they analyzed whole cities and could neglect such processes within the volume. This contribution presents first results from my PhD project where I take micrometeorological simulations for a case study site ("Bayerischer Bahnhof" in Leipzig; Saxony, Germany; 51°20', 12°22') from the ENVI-met model and calculate the UHI as well as the contributing bio geophysical processes. The results are maps of the processes that directly quantify their contribution to the total UHI at each point in the area. The benefits of this approach can be seen in the small resolution (3x3 m) of the simulation area which gives further insights into local UHI variances. Also, the effects of restructuring within quarters and methods to avoid adverse health impacts on the residents can be developed in a more precisely and sophisticated way. Zhao, L., Lee, X., Smith, R.B., Oleson, K., (2014): Strong contributions of local background climate to urban heat islands. Nature 511: 216-219, doi: 10.1038/nature13462

Precise stacking of decellularized extracellular matrix based 3D cell-laden constructs by a 3D cell printing system equipped with heating modules.

PubMed

Ahn, Geunseon; Min, Kyung-Hyun; Kim, Changhwan; Lee, Jeong-Seok; Kang, Donggu; Won, Joo-Yun; Cho, Dong-Woo; Kim, Jun-Young; Jin, Songwan; Yun, Won-Soo; Shim, Jin-Hyung

2017-08-17

Three-dimensional (3D) cell printing systems allow the controlled and precise deposition of multiple cells in 3D constructs. Hydrogel materials have been used extensively as printable bioinks owing to their ability to safely encapsulate living cells. However, hydrogel-based bioinks have drawbacks for cell printing, e.g. inappropriate crosslinking and liquid-like rheological properties, which hinder precise 3D shaping. Therefore, in this study, we investigated the influence of various factors (e.g. bioink concentration, viscosity, and extent of crosslinking) on cell printing and established a new 3D cell printing system equipped with heating modules for the precise stacking of decellularized extracellular matrix (dECM)-based 3D cell-laden constructs. Because the pH-adjusted bioink isolated from native tissue is safely gelled at 37 °C, our heating system facilitated the precise stacking of dECM bioinks by enabling simultaneous gelation during printing. We observed greater printability compared with that of a non-heating system. These results were confirmed by mechanical testing and 3D construct stacking analyses. We also confirmed that our heating system did not elicit negative effects, such as cell death, in the printed cells. Conclusively, these results hold promise for the application of 3D bioprinting to tissue engineering and drug development.

Cold welding of ultrathin gold nanowires.

PubMed

Lu, Yang; Huang, Jian Yu; Wang, Chao; Sun, Shouheng; Lou, Jun

2010-03-01

The welding of metals at the nanoscale is likely to have an important role in the bottom-up fabrication of electrical and mechanical nanodevices. Existing welding techniques use local heating, requiring precise control of the heating mechanism and introducing the possibility of damage. The welding of metals without heating (or cold welding) has been demonstrated, but only at macroscopic length scales and under large applied pressures. Here, we demonstrate that single-crystalline gold nanowires with diameters between 3 and 10 nm can be cold-welded together within seconds by mechanical contact alone, and under relatively low applied pressures. High-resolution transmission electron microscopy and in situ measurements reveal that the welds are nearly perfect, with the same crystal orientation, strength and electrical conductivity as the rest of the nanowire. The high quality of the welds is attributed to the nanoscale sample dimensions, oriented-attachment mechanisms and mechanically assisted fast surface-atom diffusion. Welds are also demonstrated between gold and silver, and silver and silver, indicating that the technique may be generally applicable.

Measuring the Heats of Water.

ERIC Educational Resources Information Center

Hunt, James L.; Tegart, Tracy L.

1994-01-01

Uses common equipment (tea kettle and vacuum bottles) to precisely measure the specific heat, latent heat of fusion, and latent heat of vaporization of water. Provides descriptions for all three experiments. (MVL)

Precision control of high temperature furnaces using an auxiliary power supply and charged practice current flow

DOEpatents

Pollock, George G.

1997-01-01

Two power supplies are combined to control a furnace. A main power supply heats the furnace in the traditional manner, while the power from the auxiliary supply is introduced as a current flow through charged particles existing due to ionized gas or thermionic emission. The main power supply provides the bulk heating power and the auxiliary supply provides a precise and fast power source such that the precision of the total power delivered to the furnace is improved.

Nanoscale temperature mapping in operating microelectronic devices

DOE PAGES

Mecklenburg, Matthew; Hubbard, William A.; White, E. R.; ...

2015-02-05

We report that modern microelectronic devices have nanoscale features that dissipate power nonuniformly, but fundamental physical limits frustrate efforts to detect the resulting temperature gradients. Contact thermometers disturb the temperature of a small system, while radiation thermometers struggle to beat the diffraction limit. Exploiting the same physics as Fahrenheit’s glass-bulb thermometer, we mapped the thermal expansion of Joule-heated, 80-nanometer-thick aluminum wires by precisely measuring changes in density. With a scanning transmission electron microscope (STEM) and electron energy loss spectroscopy (EELS), we quantified the local density via the energy of aluminum’s bulk plasmon. Rescaling density to temperature yields maps with amore » statistical precision of 3 kelvin/hertz ₋1/2, an accuracy of 10%, and nanometer-scale resolution. Lastly, many common metals and semiconductors have sufficiently sharp plasmon resonances to serve as their own thermometers.« less

High-energy Nd:glass laser for oncology

NASA Astrophysics Data System (ADS)

Boutchenkov, Vyatcheslav A.; Utenkov, Boris I.; Zaitsev, V. K.; Bayanov, Valentin I.; Serebryakov, Victor A.

1991-07-01

The use of high energy solid state lasers for the treatment of human skin neoplasia was based on the experiments and clinic studies by Helsper and Goldman (1964), McGuff (1966). The heat of precise local volume is emitted due to the pulse laser radiation. The thermal effect results in the superficial necrosis of tissues with their integrity destruction, vascular repture accompanied by bloodstoke in some cases and by capillary embolism in others. Obvious tumour destruction is note only in case of high density irradiation. General tumour destruction depends on biological neoplasia features as well as the laser type.

The Cauchy Problem in Local Spaces for the Complex Ginzburg-Landau EquationII. Contraction Methods

NASA Astrophysics Data System (ADS)

Ginibre, J.; Velo, G.

We continue the study of the initial value problem for the complex Ginzburg-Landau equation (with a > 0, b > 0, g>= 0) in initiated in a previous paper [I]. We treat the case where the initial data and the solutions belong to local uniform spaces, more precisely to spaces of functions satisfying local regularity conditions and uniform bounds in local norms, but no decay conditions (or arbitrarily weak decay conditions) at infinity in . In [I] we used compactness methods and an extended version of recent local estimates [3] and proved in particular the existence of solutions globally defined in time with local regularity of the initial data corresponding to the spaces Lr for r>= 2 or H1. Here we treat the same problem by contraction methods. This allows us in particular to prove that the solutions obtained in [I] are unique under suitable subcriticality conditions, and to obtain for them additional regularity properties and uniform bounds. The method extends some of those previously applied to the nonlinear heat equation in global spaces to the framework of local uniform spaces.

Endothelial thermotolerance impairs nanoparticle transport in tumors

PubMed Central

Bagley, Alexander F.; Scherz-Shouval, Ruth; Galie, Peter A.; Zhang, Angela Q.; Wyckoff, Jeffrey; Whitesell, Luke; Chen, Christopher S.; Lindquist, Susan; Bhatia, Sangeeta N.

2016-01-01

The delivery of diagnostic and therapeutic agents to solid tumors is limited by physical transport barriers within tumors, and such restrictions directly contribute to decreased therapeutic efficacy and the emergence of drug resistance. Nanomaterials designed to perturb the local tumor environment with precise spatiotemporal control have demonstrated potential to enhance drug delivery in preclinical models. Here, we investigated the ability of one class of heat-generating nanomaterials called plasmonic nanoantennae to enhance tumor transport in a xenograft model of ovarian cancer. We observed a temperature-dependent increase in the transport of diagnostic nanoparticles into tumors. However, a transient, reversible reduction in this enhanced transport was seen upon re-exposure to heating, consistent with the development of vascular thermotolerance. Harnessing these observations, we designed an improved treatment protocol combining plasmonic nanoantennae with diffusion-limited chemotherapies. Using a microfluidic endothelial model and genetic tools to inhibit the heat-shock response (HSR), we found that the ability of thermal preconditioning to limit heat-induced cytoskeletal disruption is an important component of vascular thermotolerance. This work therefore highlights the clinical relevance of cellular adaptations to nanomaterials and identifies molecular pathways whose modulation could improve the exposure of tumors to therapeutic agents. PMID:26122846

Endothelial Thermotolerance Impairs Nanoparticle Transport in Tumors.

PubMed

Bagley, Alexander F; Scherz-Shouval, Ruth; Galie, Peter A; Zhang, Angela Q; Wyckoff, Jeffrey; Whitesell, Luke; Chen, Christopher S; Lindquist, Susan; Bhatia, Sangeeta N

2015-08-15

The delivery of diagnostic and therapeutic agents to solid tumors is limited by physical transport barriers within tumors, and such restrictions directly contribute to decreased therapeutic efficacy and the emergence of drug resistance. Nanomaterials designed to perturb the local tumor environment with precise spatiotemporal control have demonstrated potential to enhance drug delivery in preclinical models. Here, we investigated the ability of one class of heat-generating nanomaterials called plasmonic nanoantennae to enhance tumor transport in a xenograft model of ovarian cancer. We observed a temperature-dependent increase in the transport of diagnostic nanoparticles into tumors. However, a transient, reversible reduction in this enhanced transport was seen upon reexposure to heating, consistent with the development of vascular thermotolerance. Harnessing these observations, we designed an improved treatment protocol combining plasmonic nanoantennae with diffusion-limited chemotherapies. Using a microfluidic endothelial model and genetic tools to inhibit the heat-shock response, we found that the ability of thermal preconditioning to limit heat-induced cytoskeletal disruption is an important component of vascular thermotolerance. This work, therefore, highlights the clinical relevance of cellular adaptations to nanomaterials and identifies molecular pathways whose modulation could improve the exposure of tumors to therapeutic agents. ©2015 American Association for Cancer Research.

Rotating Flow of Magnetite-Water Nanofluid over a Stretching Surface Inspired by Non-Linear Thermal Radiation.

PubMed

Mustafa, M; Mushtaq, A; Hayat, T; Alsaedi, A

2016-01-01

Present study explores the MHD three-dimensional rotating flow and heat transfer of ferrofluid induced by a radiative surface. The base fluid is considered as water with magnetite-Fe3O4 nanoparticles. Novel concept of non-linear radiative heat flux is considered which produces a non-linear energy equation in temperature field. Conventional transformations are employed to obtain the self-similar form of the governing differential system. The arising system involves an interesting temperature ratio parameter which is an indicator of small/large temperature differences in the flow. Numerical simulations with high precision are determined by well-known shooting approach. Both uniform stretching and rotation have significant impact on the solutions. The variation in velocity components with the nanoparticle volume fraction is non-monotonic. Local Nusselt number in Fe3O4-water ferrofluid is larger in comparison to the pure fluid even at low particle concentration.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Taguchi, Atsushi; Saito, Yuika; Watanabe, Koichi

Localized surface plasmon resonances were controlled at deep-ultraviolet (DUV) wavelengths by fabricating aluminum (Al) nanostructures in a size-controllable manner. Plasmon resonances were obtained at wavelengths from near-UV down to 270 nm (4.6 eV) depending on the fabricated structure size. Such precise size control was realized by the nanosphere lithography technique combined with additional microwave heating to shrink the spaces in a close-packed monolayer of colloidal nanosphere masks. By adjusting the microwave heating time, the sizes of the Al nanostructures could be controlled from 80 nm to 50 nm without the need to use nanosphere beads of different sizes. With themore » outstanding controllability and versatility of the presented fabrication technique, the fabricated Al nanostructure is promising for use as a DUV plasmonic substrate, a light-harvesting platform for mediating strong light-matter interactions between UV photons and molecules placed near the metal nanostructure.« less

High Resolution Neutron Radiography and Tomography of Hydrided Zircaloy-4 Cladding Materials

DOE Office of Scientific and Technical Information (OSTI.GOV)

Smith, Tyler S; Bilheux, Hassina Z; Ray, Holly B

2015-01-01

Neutron radiography for hydrogen analysis was performed with several Zircaloy-4 cladding samples with controlled hydrogen concentrations up to 1100 ppm. Hydrogen charging was performed in a process tube that was heated to facilitate hydrogen absorption by the metal. A correlation between the hydrogen concentration in the hydrided tubes and the neutron intensity was established, by which hydrogen content can be determined precisely in a small area (55 m x 55 m). Radiography analysis was also performed to evaluate the heating rate and its correlation with the hydrogen distribution through hydrided materials. In addition to radiography analysis, tomography experiments were performedmore » on Zircaloy-4 tube samples to study the local hydrogen distribution. Through tomography analysis a 3D reconstruction of the tube was evaluated in which an uneven hydrogen distribution in the circumferential direction can be observed.« less

A novel investigation of a micropolar fluid characterized by nonlinear constitutive diffusion model in boundary layer flow and heat transfer.

PubMed

Sui, Jize; Zhao, Peng; Cheng, Zhengdong; Zheng, Liancun; Zhang, Xinxin

2017-02-01

The rheological and heat-conduction constitutive models of micropolar fluids (MFs), which are important non-Newtonian fluids, have been, until now, characterized by simple linear expressions, and as a consequence, the non-Newtonian performance of such fluids could not be effectively captured. Here, we establish the novel nonlinear constitutive models of a micropolar fluid and apply them to boundary layer flow and heat transfer problems. The nonlinear power law function of angular velocity is represented in the new models by employing generalized " n -diffusion theory," which has successfully described the characteristics of non-Newtonian fluids, such as shear-thinning and shear-thickening fluids. These novel models may offer a new approach to the theoretical understanding of shear-thinning behavior and anomalous heat transfer caused by the collective micro-rotation effects in a MF with shear flow according to recent experiments. The nonlinear similarity equations with a power law form are derived and the approximate analytical solutions are obtained by the homotopy analysis method, which is in good agreement with the numerical solutions. The results indicate that non-Newtonian behaviors involving a MF depend substantially on the power exponent n and the modified material parameter [Formula: see text] introduced by us. Furthermore, the relations of the engineering interest parameters, including local boundary layer thickness, local skin friction, and Nusselt number are found to be fitted by a quadratic polynomial to n with high precision, which enables the extraction of the rapid predictions from a complex nonlinear boundary-layer transport system.

A novel investigation of a micropolar fluid characterized by nonlinear constitutive diffusion model in boundary layer flow and heat transfer

PubMed Central

Zhao, Peng; Cheng, Zhengdong; Zheng, Liancun; Zhang, Xinxin

2017-01-01

The rheological and heat-conduction constitutive models of micropolar fluids (MFs), which are important non-Newtonian fluids, have been, until now, characterized by simple linear expressions, and as a consequence, the non-Newtonian performance of such fluids could not be effectively captured. Here, we establish the novel nonlinear constitutive models of a micropolar fluid and apply them to boundary layer flow and heat transfer problems. The nonlinear power law function of angular velocity is represented in the new models by employing generalized “n-diffusion theory,” which has successfully described the characteristics of non-Newtonian fluids, such as shear-thinning and shear-thickening fluids. These novel models may offer a new approach to the theoretical understanding of shear-thinning behavior and anomalous heat transfer caused by the collective micro-rotation effects in a MF with shear flow according to recent experiments. The nonlinear similarity equations with a power law form are derived and the approximate analytical solutions are obtained by the homotopy analysis method, which is in good agreement with the numerical solutions. The results indicate that non-Newtonian behaviors involving a MF depend substantially on the power exponent n and the modified material parameter K0 introduced by us. Furthermore, the relations of the engineering interest parameters, including local boundary layer thickness, local skin friction, and Nusselt number are found to be fitted by a quadratic polynomial to n with high precision, which enables the extraction of the rapid predictions from a complex nonlinear boundary-layer transport system. PMID:28344433

Precision control of high temperature furnaces using an auxiliary power supply and charged particle current flow

DOEpatents

Pollock, G.G.

1997-01-28

Two power supplies are combined to control a furnace. A main power supply heats the furnace in the traditional manner, while the power from the auxiliary supply is introduced as a current flow through charged particles existing due to ionized gas or thermionic emission. The main power supply provides the bulk heating power and the auxiliary supply provides a precise and fast power source such that the precision of the total power delivered to the furnace is improved. 5 figs.

Improving personalized link prediction by hybrid diffusion

NASA Astrophysics Data System (ADS)

Liu, Jin-Hu; Zhu, Yu-Xiao; Zhou, Tao

2016-04-01

Inspired by traditional link prediction and to solve the problem of recommending friends in social networks, we introduce the personalized link prediction in this paper, in which each individual will get equal number of diversiform predictions. While the performances of many classical algorithms are not satisfactory under this framework, thus new algorithms are in urgent need. Motivated by previous researches in other fields, we generalize heat conduction process to the framework of personalized link prediction and find that this method outperforms many classical similarity-based algorithms, especially in the performance of diversity. In addition, we demonstrate that adding one ground node that is supposed to connect all the nodes in the system will greatly benefit the performance of heat conduction. Finally, better hybrid algorithms composed of local random walk and heat conduction have been proposed. Numerical results show that the hybrid algorithms can outperform other algorithms simultaneously in all four adopted metrics: AUC, precision, recall and hamming distance. In a word, this work may shed some light on the in-depth understanding of the effect of physical processes in personalized link prediction.

Targeted Delivery of Hyaluronan-Immobilized Magnetic Ceramic Nanocrystals.

PubMed

Wu, Hsi-Chin; Wang, Tzu-Wei; Hsieh, Shun-Yu; Sun, Jui-Sheng; Kang, Pei-Leun

2016-01-01

Effective cancer therapy relies on delivering the therapeutic agent precisely to the target site to improve the treatment outcome and to minimize side effects. Although surgery, chemotherapy, and radiotherapy are the standard methods commonly used in clinics, hyperthermia has been developed as a new and promising strategy for cancer therapy. In this study, magnetic bioceramic hydroxyapatite (mHAP) nanocrystals have been developed as heat mediator for intracellular hyperthermia. Hyaluronic acid (HA) modified mHAP nanocrystals are synthesized by a wet chemical precipitation process to achieve active targeting. The results demonstrate that the HA targeting moiety conjugated by a poly(ethylene glycol) (PEG) spacer arm is successfully immobilized on the surface of mHAP. The HA-modified mHAP possesses relatively good biocompatibility, an adequate biodegradation rate and superparamagnetic properties. The HA-modified mHAP could be localized and internalized into HA receptor-overexpressed malignant cells (e.g., MDA-MB-231 cell) and used as the heat generating agent for intracellular hyperthermia. The results from this study indicate that biocompatible HA-modified mHAP shows promise as a novel heat mediator and a specific targeting nanoagent for intracellular hyperthermia cancer therapy.

Photo-thermal nanosystems for diseased cell treatment

NASA Astrophysics Data System (ADS)

Raeesi, Vahid

The prevalence of cancer and infectious disease demands for development of more effective treatment technologies. Current standard chemo- and radiotherapy for cancer offer only relative therapeutic efficacy at the cost of significant side-effects. On the other hand, resistance of microbes to current antibiotics has raised serious concern in public health sectors such as hospitals. Thermal therapy is an alternative technique that employs high temperatures to treat diseased cells via direct and indirect heat effects. Owing to its nature, this technique can offer enhanced therapeutic efficacy in local diseased regions via either mono- or combinatorial platforms and very minimal side-effects. However, existing bulk heating systems are limited in providing selective and controlled temperature rise in the desired region at tissue/cellular scales. This compromises the therapeutic efficacy of the treatment and increases the risk of off-target heating in healthy tissues. In this thesis, we propose the use of heat-generating nanoparticles to precisely target heat into small regions and study how they can be applied in cancer and bacteria treatment. Our model nanoparticle system generates heat by light stimulation. Different nanosystems based on this particle are developed and their thermal effects on therapeutic distribution are explored at tumor tissue and cellular scales. In addition, the thermal effect of these nanoparticles is utilized to overcome microbial resistance. By mechanistic understanding of nanoparticle thermal effects at different length scales, this research helps to rationalize proper design and development of heat- generating nanomedicine for cancer and microbial treatments.

Role of Large Eddies in the Breakdown of the Reynolds Analogy in the Unstable Atmospheric Surface Layer

NASA Astrophysics Data System (ADS)

Mccoll, K. A.; Van Heerwaarden, C.; Katul, G. G.; Gentine, P.; Entekhabi, D.

2016-12-01

While the break-down in similarity between turbulent transport of heat and momentum (or Reynolds analogy) is not disputed in the atmospheric surface layer (ASL) under unstably stratified conditions, the causes of this breakdown remain the subject of some debate. One reason for the break-down is hypothesized to be due to a change in the topology of the coherent structures and how they differently transport heat and momentum. As instability increases, coherent structures that are confined to the near-wall region transition to thermal plumes, spanning the entire boundary layer depth. Monin-Obukhov Similarity Theory (MOST), which hypothesizes that only local length scales play a role in ASL turbulent transport, implicitly assumes that thermal plumes and other large-scale structures are inactive (i.e., they do not contribute to turbulent transport despite their large energy content). Widely adopted mixing-length models for the ASL also rest on this assumption. The difficulty of characterizing low-wavenumber turbulent motions with field observations motivates the use of high-resolution Direct Numerical Simulations (DNS) that are free from sub-grid scale parameterizations and ad-hoc assumptions near the boundary. Despite the low Reynolds number, mild stratification and idealized geometry, DNS-estimated MOST functions are consistent with field experiments as are key low-frequency features of the vertical velocity variance and buoyancy spectra. Parsimonious spectral models for MOST stability correction functions for momentum (φm) and heat (φh) are derived based on idealized vertical velocity variance and buoyancy spectra fit to the corresponding DNS spectra. For φm, a spectral model requiring a local length scale (evolving with local stability conditions) that matches DNS and field observations is derived. In contrast, for φh, the aforementioned model is substantially biased unless contributions from larger length scales are also included. These results suggest that ASL heat transport cannot be precisely MO-similar, and that the breakdown of the Reynolds analogy is at least partially caused by the influence of large eddies on turbulent heat transport.

Ex situ themo-catalytic upgrading of biomass pyrolysis vapors using a traveling wave microwave reactor

USDA-ARS?s Scientific Manuscript database

Microwave heating offers a number of advantages over conventional heating methods, such as, rapid and volumetric heating, precise temperature control, energy efficiency and lower temperature gradient. In this article we demonstrate the use of 2450 MHz microwave traveling wave reactor to heat the cat...

Interface Shape Control Using Localized Heating during Bridgman Growth

NASA Technical Reports Server (NTRS)

Volz, M. P.; Mazuruk, K.; Aggarwal, M. D.; Croll, A.

2008-01-01

Numerical calculations were performed to assess the effect of localized radial heating on the melt-crystal interface shape during vertical Bridgman growth. System parameters examined include the ampoule, melt and crystal thermal conductivities, the magnitude and width of localized heating, and the latent heat of crystallization. Concave interface shapes, typical of semiconductor systems, could be flattened or made convex with localized heating. Although localized heating caused shallower thermal gradients ahead of the interface, the magnitude of the localized heating required for convexity was less than that which resulted in a thermal inversion ahead of the interface. A convex interface shape was most readily achieved with ampoules of lower thermal conductivity. Increasing melt convection tended to flatten the interface, but the amount of radial heating required to achieve a convex interface was essentially independent of the convection intensity.

Effect of whole-body and local heating on cutaneous vasoconstrictor responses in humans

NASA Technical Reports Server (NTRS)

Wilson, Thad E.; Cui, Jian; Crandall, Craig G.

2002-01-01

Animal studies suggest that alpha-adrenergic-mediated vasoconstriction is compromised during whole-body heating. The purpose of this study was to identify whether whole-body heating and/or local surface heating reduce cutaneous alpha-adrenergic vasoconstrictor responsiveness in human skin. Protocol I: Six subjects were exposed to neutral skin temperature (i.e., 34 degrees C), whole-body heating, and local heating of forearm skin to increase skin blood flow to the same relative magnitude as that observed during whole-body heating. Protocol II: In eight subjects forearm skin was locally heated to 34, 37, 40, and 42 degrees C. During both protocols, alpha-adrenergic vasoconstrictor responsiveness was assessed by local delivery of norepinephrine (NE) via intradermal microdialysis. Skin blood flow was continuously monitored over each microdialysis membrane via laser-Doppler flowmetry. In protocol I, whole-body and local heating caused similar increases in cutaneous vascular conductance (CVC). The EC50 (log NE dose) of the dose-response curves for both whole body (-4.2 +/- 0.1 M) and local heating (-4.7 +/- 0.4 M) were significantly greater (i.e., high dose required to cause 50% reduction in CVC) relative to neutral skin temperature (- 5.6 +/- 0.0 M; P<0.05 for both). In both local and whole-body heated conditions CVC did not return to pre-heating values even at the highest dose of NE. In protocol II, calculated EC50 for 34, 37, 40, and 42 degrees C local heating was - 5.5 +/- 0.4, -4.6 +/- 0.3, -4.5 +/- 0.3, - 4.2 +/- 0.4 M, respectively. Statistical analyses revealed that the EC50 for 37,40 and 42 degrees C were significantly greater than the EC50 for 34 degrees C. These results indicate that even during administration of high concentrations of NE, alpha-adrenergic vasoconstriction does not fully compensate for local heating and whole-body heating induced vasodilatation in young, healthy subjects. Moreover, these data suggest that elevated local temperatures, above 37 degrees C, and whole-body heating similarly attenuate cutaneous alpha-adrenergic vasoconstriction responsiveness.

Heat Exchanger Can Assembly for Provision of Helium Coolant Streams for Cryomodule Testing below 2K

NASA Astrophysics Data System (ADS)

Smith, E. N.; Eichhorn, R.; Quigley, P.; Sabol, D.; Shore, C.; Widger, D.

2017-02-01

A series of heat exchanger can (HXC) assemblies have been designed, constructed and built to utilize existing 4.2 K liquefaction and compressor capabilities to provide helium gas coolant streams of 80 K, 4.5 K, and liquid from 1.6 to 2.0 K for operating cryomodules containing from one to six superconducting RF cavities built for an energy recovery linear accelerator. Designs for the largest assemblies required up to 100 W of cooling at 1.8 K with precise temperature control, especially during cool-down, and up to 2000 W at 80 K (with a 40 K temperature rise). A novel feature of these assemblies was the use of relatively inexpensive brazed stainless steel plate heat exchangers intended for room-temperature operation with water or oil, but which in practice worked well at cryogenic temperatures. The choice of operating temperatures/pressures were to provide single-phase helium flow for better control of coolant distribution in the 80 K and 4.5 K streams, to take advantage of locally elevated heat capacity near the critical point for the 4.5 K stream, and in the region below 2 K to get the best possible Q from the niobium cavities under test.

Response of eddy activities to localized diabatic heating in Held-Suarez simulations

NASA Astrophysics Data System (ADS)

Lin, Yanluan; Zhang, Jishi; Li, Xingrui; Deng, Yi

2018-01-01

Widespread air pollutions, such as black carbon over East Asia in recent years, could induce a localized diabatic heating, and thus lead to localized static stability and meridional temperature gradient (MTG) changes. Although effect of static stability and MTG on eddies has been addressed by the linear baroclinic instability theory, impacts of a localized heating on mid-latitude eddy activities have not been well explored and quantified. Via a series of idealized global Held-Suarez simulations with different magnitudes of localized heating at different altitudes and latitudes, responses of mid-latitude eddy activity and circulation to these temperature perturbations are systematically investigated. Climatologically, the localized heating in the lower atmosphere induces a wave-like response of eddy activity near the mid-latitude jet stream. Over the heating region, eddy activity tends to be weakening due to the increased static stability. However, there are cyclonic anomalies over the upstream and downstream of the heating region. The zonal mean eddy activity weakens along the baroclinic zone due to reduced MTG and increased static stability. Furthermore, the response of eddy activity increased as the heating magnitude is increased and moved to higher altitudes. The influence of the heating decreases as the heating is prescribed further away from the climatological mid-latitude jet. This implies that the localized heating is most effective over the region with the maximum baroclinicity. Besides, enhanced storm track downstream of the localized heating area found here suggests that increased aerosols over East Asia might strengthen the North Pacific storm track.

Human local and total heat losses in different temperature.

PubMed

Wang, Lijuan; Yin, Hui; Di, Yuhui; Liu, Yanfeng; Liu, Jiaping

2016-04-01

This study investigates the effects of operative temperature on the local and total heat losses, and the relationship between the heat loss and thermal sensation. 10 local parts of head, neck, chest, abdomen, upper arm, forearm, hand, thigh, leg and foot are selected. In all these parts, convection, radiation, evaporation, respiration, conduction and diffusion heat losses are analyzed when operative temperature is 23, 28, 33 and 37 °C. The local heat losses show that the radiation and convection heat losses are mainly affected by the area of local body, and the heat loss of the thigh is the most in the ten parts. The evaporation heat loss is mainly affected by the distribution of sweat gland, and the heat loss of the chest is the most. The total heat loss of the local body shows that in low temperature, the thigh, leg and chest have much heat loss, while in high temperature, the chest, abdomen, thigh and head have great heat loss, which are useful for clothing design. The heat losses of the whole body show that as the operative temperature increases, the radiation and convection heat losses decrease, the heat losses of conduction, respiration, and diffusion are almost constant, and the evaporation heat loss increases. By comparison, the heat loss ratios of the radiation, convection and sweat evaporation, are in agreement with the previous researches. At last, the formula about the heat loss ratio of convection and radiation is derived. It's useful for thermal comfort evaluation and HVAC (heating, ventilation and air conditioning) design. Copyright © 2016 Elsevier Inc. All rights reserved.

A study of gas solubilities and transport properties in fuel cell electrolytes

NASA Technical Reports Server (NTRS)

Walker, R. D. J.

1972-01-01

An analysis of the rate of heat generation on the dissolution of sparingly soluble gas in electrolytes was made, and it leads to the conclusion that the temperature changes to be expected are much too small to be measured with precision owing to the slowness of the gas dissolution. It appears that more accurate gas solubility measurements are the only real hope of improved precision in heats of solution and other thermodynamic properties.

A laser-induced heat flux technique for convective heat transfer measurements in high speed flows

NASA Technical Reports Server (NTRS)

Porro, A. R.; Keith, T. G., Jr.; Hingst, W. R.

1991-01-01

A technique is developed to measure the local convective heat transfer coefficient on a model surface in a supersonic flow field. The technique uses a laser to apply a discrete local heat flux at the model test surface, and an infrared camera system determines the local temperature distribution due to the heating. From this temperature distribution and an analysis of the heating process, a local convective heat transfer coefficient is determined. The technique was used to measure the local surface convective heat transfer coefficient distribution on a flat plate at nominal Mach numbers of 2.5, 3.0, 3.5, and 4.0. The flat plate boundary layer initially was laminar and became transitional in the measurement region. The experimentally determined convective heat transfer coefficients were generally higher than the theoretical predictions for flat plate laminar boundary layers. However, the results indicate that this nonintrusive optical measurement technique has the potential to measure surface convective heat transfer coefficients in high speed flow fields.

A laser-induced heat flux technique for convective heat transfer measurements in high speed flows

NASA Technical Reports Server (NTRS)

Porro, A. R.; Keith, T. G., Jr.; Hingst, W. R.

1991-01-01

A technique is developed to measure the local convective heat transfer coefficient on a model surface in a supersonic flow field. The technique uses a laser to apply a discrete local heat flux at the model test surface, and an infrared camera system determines the local temperature distribution due to the heating. From this temperature distribution and an analysis of the heating process, a local convective heat transfer coefficient is determined. The technique was used to measure the local surface convective heat transfer coefficient distribution on a flat plate at nominal Mach numbers of 2.5, 3.0, 3.5, and 4.0. The flat plate boundary layer initially was laminar and became transitional in the measurement region. The experimentally determined convective heat transfer coefficients were generally higher than the theoretical predictions for flat plate laminar boundary layers. However, the results indicate that this nonintrusive optical measurement technique has the potential to measure surface convective heat transfer coefficients in high-speed flowfields.

Zero Boil-Off Tank (ZBOT) Experiment

NASA Technical Reports Server (NTRS)

Mcquillen, John

2016-01-01

The Zero-Boil-Off Tank (ZBOT) experiment has been developed as a small scale ISS experiment aimed at delineating important fluid flow, heat and mass transport, and phase change phenomena that affect cryogenic storage tank pressurization and pressure control in microgravity. The experiments use a simulant transparent low boiling point fluid (PnP) in a sealed transparent Dewar to study and quantify: (a) fluid flow and thermal stratification during pressurization; (b) mixing, thermal destratification, depressurization, and jet-ullage penetration during pressure control by jet mixing. The experiment will provide valuable microgravity empirical two-phase data associated with the above-mentioned physical phenomena through highly accurate local wall and fluid temperature and pressure measurements, full-field phase-distribution and flow visualization. Moreover, the experiments are performed under tightly controlled and definable heat transfer boundary conditions to provide reliable high-fidelity data and precise input as required for validation verification of state-of-the-art two-phase CFD models developed as part of this research and by other groups in the international scientific and cryogenic fluid management communities.

Research on the tool holder mode in high speed machining

NASA Astrophysics Data System (ADS)

Zhenyu, Zhao; Yongquan, Zhou; Houming, Zhou; Xiaomei, Xu; Haibin, Xiao

2018-03-01

High speed machining technology can improve the processing efficiency and precision, but also reduce the processing cost. Therefore, the technology is widely regarded in the industry. With the extensive application of high-speed machining technology, high-speed tool system has higher and higher requirements on the tool chuck. At present, in high speed precision machining, several new kinds of clip heads are as long as there are heat shrinkage tool-holder, high-precision spring chuck, hydraulic tool-holder, and the three-rib deformation chuck. Among them, the heat shrinkage tool-holder has the advantages of high precision, high clamping force, high bending rigidity and dynamic balance, etc., which are widely used. Therefore, it is of great significance to research the new requirements of the machining tool system. In order to adapt to the requirement of high speed machining precision machining technology, this paper expounds the common tool holder technology of high precision machining, and proposes how to select correctly tool clamping system in practice. The characteristics and existing problems are analyzed in the tool clamping system.

Boiling local heat transfer enhancement in minichannels using nanofluids

PubMed Central

2013-01-01

This paper reports an experimental study on nanofluid convective boiling heat transfer in parallel rectangular minichannels of 800 μm hydraulic diameter. Experiments are conducted with pure water and silver nanoparticles suspended in water base fluid. Two small volume fractions of silver nanoparticles suspended in water are tested: 0.000237% and 0.000475%. The experimental results show that the local heat transfer coefficient, local heat flux, and local wall temperature are affected by silver nanoparticle concentration in water base fluid. In addition, different correlations established for boiling flow heat transfer in minichannels or macrochannels are evaluated. It is found that the correlation of Kandlikar and Balasubramanian is the closest to the water boiling heat transfer results. The boiling local heat transfer enhancement by adding silver nanoparticles in base fluid is not uniform along the channel flow. Better performances and highest effect of nanoparticle concentration on the heat transfer are obtained at the minichannels entrance. PMID:23506445

Customization of UWB 3D-RTLS Based on the New Uncertainty Model of the AoA Ranging Technique

PubMed Central

Jachimczyk, Bartosz; Dziak, Damian; Kulesza, Wlodek J.

2017-01-01

The increased potential and effectiveness of Real-time Locating Systems (RTLSs) substantially influence their application spectrum. They are widely used, inter alia, in the industrial sector, healthcare, home care, and in logistic and security applications. The research aims to develop an analytical method to customize UWB-based RTLS, in order to improve their localization performance in terms of accuracy and precision. The analytical uncertainty model of Angle of Arrival (AoA) localization in a 3D indoor space, which is the foundation of the customization concept, is established in a working environment. Additionally, a suitable angular-based 3D localization algorithm is introduced. The paper investigates the following issues: the influence of the proposed correction vector on the localization accuracy; the impact of the system’s configuration and LS’s relative deployment on the localization precision distribution map. The advantages of the method are verified by comparing them with a reference commercial RTLS localization engine. The results of simulations and physical experiments prove the value of the proposed customization method. The research confirms that the analytical uncertainty model is the valid representation of RTLS’ localization uncertainty in terms of accuracy and precision and can be useful for its performance improvement. The research shows, that the Angle of Arrival localization in a 3D indoor space applying the simple angular-based localization algorithm and correction vector improves of localization accuracy and precision in a way that the system challenges the reference hardware advanced localization engine. Moreover, the research guides the deployment of location sensors to enhance the localization precision. PMID:28125056

Customization of UWB 3D-RTLS Based on the New Uncertainty Model of the AoA Ranging Technique.

PubMed

Jachimczyk, Bartosz; Dziak, Damian; Kulesza, Wlodek J

2017-01-25

The increased potential and effectiveness of Real-time Locating Systems (RTLSs) substantially influence their application spectrum. They are widely used, inter alia, in the industrial sector, healthcare, home care, and in logistic and security applications. The research aims to develop an analytical method to customize UWB-based RTLS, in order to improve their localization performance in terms of accuracy and precision. The analytical uncertainty model of Angle of Arrival (AoA) localization in a 3D indoor space, which is the foundation of the customization concept, is established in a working environment. Additionally, a suitable angular-based 3D localization algorithm is introduced. The paper investigates the following issues: the influence of the proposed correction vector on the localization accuracy; the impact of the system's configuration and LS's relative deployment on the localization precision distribution map. The advantages of the method are verified by comparing them with a reference commercial RTLS localization engine. The results of simulations and physical experiments prove the value of the proposed customization method. The research confirms that the analytical uncertainty model is the valid representation of RTLS' localization uncertainty in terms of accuracy and precision and can be useful for its performance improvement. The research shows, that the Angle of Arrival localization in a 3D indoor space applying the simple angular-based localization algorithm and correction vector improves of localization accuracy and precision in a way that the system challenges the reference hardware advanced localization engine. Moreover, the research guides the deployment of location sensors to enhance the localization precision.

40 CFR 61.18 - Incorporations by reference.

Code of Federal Regulations, 2010 CFR

2010-07-01

... D2382-76, 88, Heat of Combustion of Hydrocarbon Fuels by Bomb Calorimeter (High-Precision Method), IBR... Combustion of Liquid Hydrocarbon Fuels by Bomb Calorimeter (Precision Method), IBR approved for § 61.245(e)(3...

The influence of local versus global heat on the healing of chronic wounds in patients with diabetes.

PubMed

Petrofsky, Jerrold S; Lawson, Daryl; Suh, Hye Jin; Rossi, Christine; Zapata, Karina; Broadwell, Erin; Littleton, Lindsay

2007-12-01

In a previous study, it was shown that placing a subject with chronic diabetic ulcers in a warm room prior to the use of electrical stimulation dramatically increased the healing rate. However, global heating is impractical in many therapeutic environments, and therefore in the present investigation the effect of global heat versus using a local heat source to warm the wound was investigated. Twenty-nine male and female subjects participated in a series of experiments to determine the healing associated with electrical stimulation with the application of local heat through a heat lamp compared to global heating of the subject in a warm room. Treatment consisted of biphasic electrical stimulation at currents at 20 mA for 30 min three times per week for 4 weeks in either a 32 degrees C room or, with the application of local heat, to raise skin temperature to 37 degrees C. Skin blood flow was measured by a laser Doppler imager. Blood flow increased with either local or global heating. During electrical stimulation, blood flow almost doubled on the outside and on the edge of the wound with a smaller increase in the center of the wound. However, the largest increase in blood flow was in the subjects exposed to global heating. Further, healing rates, while insignificant for subjects who did not receive electrical stimulation, showed 74.5 +/- 23.4% healing with global heat and 55.3 +/- 31.1% healing with local heat in 1 month; controls actually had a worsening of their wounds. The best healing modality was global heat. However, there was still a significant advantage in healing with local heat.

Localized mold heating with the aid of selective induction for injection molding of high aspect ratio micro-features

NASA Astrophysics Data System (ADS)

Park, Keun; Lee, Sang-Ik

2010-03-01

High-frequency induction is an efficient, non-contact means of heating the surface of an injection mold through electromagnetic induction. Because the procedure allows for the rapid heating and cooling of mold surfaces, it has been recently applied to the injection molding of thin-walled parts or micro/nano-structures. The present study proposes a localized heating method involving the selective use of mold materials to enhance the heating efficiency of high-frequency induction heating. For localized induction heating, a composite injection mold of ferromagnetic material and paramagnetic material is used. The feasibility of the proposed heating method is investigated through numerical analyses in terms of its heating efficiency for localized mold surfaces and in terms of the structural safety of the composite mold. The moldability of high aspect ratio micro-features is then experimentally compared under a variety of induction heating conditions.

Global surface temperature/heat transfer measurements using infrared imaging

NASA Technical Reports Server (NTRS)

Daryabeigi, Kamran

1992-01-01

A series of studies were conducted to evaluate the use of scanning radiometric infrared imaging systems for providing global surface temperature/heat transfer measurements in support of hypersonic wind tunnel testing. The in situ precision of the technique with narrow temperature span setting over the temperature range of 20 to 200 C was investigated. The precision of the technique over wider temperature span settings was also determined. The accuracy of technique for providing aerodynamic heating rates was investigated by performing measurements on a 10.2-centimeter hemisphere model in the Langley 31-inch Mach 10 tunnel, and comparing the results with theoretical predictions. Data from tests conducted on a generic orbiter model in this tunnel are also presented.

Ultrafast Microwave Welding/Reinforcing Approach at the Interface of Thermoplastic Materials.

PubMed

Poyraz, Selcuk; Zhang, Lin; Schroder, Albrecht; Zhang, Xinyu

2015-10-14

As an attempt to address the needs and tackle the challenges in welding of thermoplastic materials (TPMs), a novel process was performed via short-term microwave (MW) heating of a specific composite, made up of conducting polypyrrole nanogranule (PPy NG) coated carbon and catalyst source precursor (ferrocene) fine particles, at substrate polypropylene (PP) dog bone pieces' interface. Upon vigorous interactions between MWs and electromagnetic absorbent PPy NG coating, the energy was transformed into a large amount of heat leading to a drastic temperature increase that was simultaneously used for the instant carbonization of PPy and the decomposition of fine ferrocene particles, which resulted in multiwalled carbon nanotubes (CNTs) growth at the interface. Meanwhile, the as-grown CNTs on the surface conveyed the heat into the adjacent bulk PP and caused locally molten surface layers' formation. Eventually, the light pressure applied at the interface during the heating process squeezed the molten layers together and a new weld was generated. The method is considerably advantageous compared to other alternatives due to (i) its fast, straightforward, and affordable nature, (ii) its applicability at ambient conditions without the need of any extra equipment or chemicals, and also (iii) its ability to provide clean, durable, and functional welds, via precisely controlling process parameters, without causing any thermal distortion or physical alterations in the bulk TPM. Thus, it is believed that this novel welding process will become much preferable for the manufacturing of next-generation TPM composites in large scale, through short-term MW heating.

Understanding Latent Heat of Vaporization.

ERIC Educational Resources Information Center

Linz, Ed

1995-01-01

Presents a simple exercise for students to do in the kitchen at home to determine the latent heat of vaporization of water using typical household materials. Designed to stress understanding by sacrificing precision for simplicity. (JRH)

Turbine heat transfer

NASA Technical Reports Server (NTRS)

Rohde, J. E.

1982-01-01

Objectives and approaches to research in turbine heat transfer are discussed. Generally, improvements in the method of determining the hot gas flow through the turbine passage is one area of concern, as is the cooling air flow inside the airfoil, and the methods of predicting the heat transfer rates on the hot gas side and on the coolant side of the airfoil. More specific areas of research are: (1) local hot gas recovery temperatures along the airfoil surfaces; (2) local airfoil wall temperature; (3) local hot gas side heat transfer coefficients on the airfoil surfaces; (4) local coolant side heat transfer coefficients inside the airfoils; (5) local hot gas flow velocities and secondary flows at real engine conditions; and (6) local delta strain range of the airfoil walls.

Precise determination of the heat delivery during in vivo magnetic nanoparticle hyperthermia with infrared thermography

NASA Astrophysics Data System (ADS)

Rodrigues, Harley F.; Capistrano, Gustavo; Mello, Francyelli M.; Zufelato, Nicholas; Silveira-Lacerda, Elisângela; Bakuzis, Andris F.

2017-05-01

Non-invasive and real-time monitoring of the heat delivery during magnetic nanoparticle hyperthermia (MNH) is of fundamental importance to predict clinical outcomes for cancer treatment. Infrared thermography (IRT) can determine the surface temperature due to three-dimensional heat delivery inside a subcutaneous tumor, an argument that is supported by numerical simulations. However, for precise temperature determination, it is of crucial relevance to use a correct experimental configuration. This work reports an MNH study using a sarcoma 180 murine tumor containing 3.9 mg of intratumorally injected manganese-ferrite nanoparticles. MNH was performed at low field amplitude and non-uniform field configuration. Five 30 min in vivo magnetic hyperthermia experiments were performed, monitoring the surface temperature with a fiber optical sensor and thermal camera at distinct angles with respect to the animal’s surface. The results indicate that temperature errors as large as 7~\\circ C can occur if the experiment is not properly designed. A new IRT error model is found to explain the data. More importantly, we show how to precisely monitor temperature with IRT during hyperthermia, which could positively impact heat dosimetry and clinical planning.

Precise determination of the heat delivery during in vivo magnetic nanoparticle hyperthermia with infrared thermography.

PubMed

Rodrigues, Harley F; Capistrano, Gustavo; Mello, Francyelli M; Zufelato, Nicholas; Silveira-Lacerda, Elisângela; Bakuzis, Andris F

2017-05-21

Non-invasive and real-time monitoring of the heat delivery during magnetic nanoparticle hyperthermia (MNH) is of fundamental importance to predict clinical outcomes for cancer treatment. Infrared thermography (IRT) can determine the surface temperature due to three-dimensional heat delivery inside a subcutaneous tumor, an argument that is supported by numerical simulations. However, for precise temperature determination, it is of crucial relevance to use a correct experimental configuration. This work reports an MNH study using a sarcoma 180 murine tumor containing 3.9 mg of intratumorally injected manganese-ferrite nanoparticles. MNH was performed at low field amplitude and non-uniform field configuration. Five 30 min in vivo magnetic hyperthermia experiments were performed, monitoring the surface temperature with a fiber optical sensor and thermal camera at distinct angles with respect to the animal's surface. The results indicate that temperature errors as large as [Formula: see text]C can occur if the experiment is not properly designed. A new IRT error model is found to explain the data. More importantly, we show how to precisely monitor temperature with IRT during hyperthermia, which could positively impact heat dosimetry and clinical planning.

Investigating Oil-Prone Kerogen Conversion to Hydrocarbons Using AFM-based Infrared Spectroscopy

NASA Astrophysics Data System (ADS)

Eoghan, D.; Cook, D.; Hackley, P. C.; Kjoller, K.; Dawson, D.; Shetty, R.

2016-12-01

Understanding in situ chemical changes occurring during thermal conversion of oil-prone kerogen to hydrocarbons can provide fundamental information regarding the origin of the earth's fossil fuel endowment and reduce uncertainty in hydrocarbon prospecting and resource assessment. Tasmanites algal bodies were studied using an Atomic Force Microscope-based IR spectroscopy technique (AFM-IR) that offers chemical characterization of organic materials with spatial resolution below the diffraction limit. The AFM allows precise positioning within the algal bodies. A tunable IR laser irradiates the sample under the AFM probe. At absorbing wavenumbers, the sample heats up and expands. The AFM detects the expansion of the material under the probe tip to generate local IR spectra. The Tasmanites algal bodies from the Devonian-Mississippian Woodford Shale were contained in two polished rock fragment pellets. To simulate maturation, one was subjected to isothermal hydrous pyrolysis at 320 °C for 72 hours. AFM-IR spectra were collected at multiple sites on algal bodies in both samples (Figure 1). The aromatic C=C ring stretching at 1600 cm-1 (unheated) shifted to 1606 cm-1 with increased absorption in the heated algal bodies, indicating development of increased aromaticity with thermal maturation. The ratio of the 1606 cm-1 peak to peaks at 1708 cm-1 (C=O stretching) and 1460 cm-1 (CH2 wag) was higher in the heated sample, indicating loss of oxygenated functional groups and aliphatic components with thermal advance. A shift of the 1372 cm-1 peak to 1376 cm-1 with lower absorption in the heated samples suggests reduction in the abundance of methyl substituents and development of preferred localization. These results are consistent with extant information from FTIR analysis and demonstrate the ability of AFM-IR to provide in situ characterization of organic matter with respect to thermal maturity advance, and its application to understanding conversion of oil-prone kerogen to hydrocarbons. AFM-IR also showed chemical variations within an algal body, from the central region compared to the folded tips. Future work will examine nanoscale characterization of localized compositional variations in Tasmanites bodies in relation to spectral fluorescence parameters to determine preferred sites of kerogen cracking.

Particle-in-cell simulations of the plasma interaction with poloidal gaps in the ITER divertor outer vertical target

NASA Astrophysics Data System (ADS)

Komm, M.; Gunn, J. P.; Dejarnac, R.; Pánek, R.; Pitts, R. A.; Podolník, A.

2017-12-01

Predictive modelling of the heat flux distribution on ITER tungsten divertor monoblocks is a critical input to the design choice for component front surface shaping and for the understanding of power loading in the case of small-scale exposed edges. This paper presents results of particle-in-cell (PIC) simulations of plasma interaction in the vicinity of poloidal gaps between monoblocks in the high heat flux areas of the ITER outer vertical target. The main objective of the simulations is to assess the role of local electric fields which are accounted for in a related study using the ion orbit approach including only the Lorentz force (Gunn et al 2017 Nucl. Fusion 57 046025). Results of the PIC simulations demonstrate that even if in some cases the electric field plays a distinct role in determining the precise heat flux distribution, when heat diffusion into the bulk material is taken into account, the thermal responses calculated using the PIC or ion orbit approaches are very similar. This is a consequence of the small spatial scales over which the ion orbits distribute the power. The key result of this study is that the computationally much less intensive ion orbit approximation can be used with confidence in monoblock shaping design studies, thus validating the approach used in Gunn et al (2017 Nucl. Fusion 57 046025).

On the Composition and Temperature of the Terrestrial Planetary Core

NASA Astrophysics Data System (ADS)

Fei, Yingwei

2013-06-01

The existence of liquid cores of terrestrial planets such as the Earth, Mar, and Mercury has been supported by various observation. The liquid state of the core provides a unique opportunity for us to estimate the temperature of the core if we know the melting temperature of the core materials at core pressure. Dynamic compression by shock wave, laser-heating in diamond-anvil cell, and resistance-heating in the multi-anvil device can melt core materials over a wide pressure range. There have been significant advances in both dynamic and static experimental techniques and characterization tool. In this tal, I will review some of the recent advances and results relevant to the composition and thermal state of the terrestrial core. I will also present new development to analyze the quenched samples recovered from laser-heating diamond-anvil cell experiments using combination of focused ion beam milling, high-resolution SEM imaging, and quantitative chemical analysi. With precision milling of the laser-heating spo, the melting point and element partitioning between solid and liquid can be precisely determined. It is also possible to re-construct 3D image of the laser-heating spot at multi-megabar pressures to better constrain melting point and understanding melting process. The new techniques allow us to extend precise measurements of melting relations to core pressures, providing better constraint on the temperature of the cor. The research is supported by NASA and NSF grants.

Joule heating monitoring in a microfluidic channel by observing the Brownian motion of an optically trapped microsphere.

PubMed

Brans, Toon; Strubbe, Filip; Schreuer, Caspar; Vandewiele, Stijn; Neyts, Kristiaan; Beunis, Filip

2015-09-01

Electric fields offer a variety of functionalities to Lab-on-a-Chip devices. The use of these fields often results in significant Joule heating, affecting the overall performance of the system. Precise knowledge of the temperature profile inside a microfluidic device is necessary to evaluate the implications of heat dissipation. This article demonstrates how an optically trapped microsphere can be used as a temperature probe to monitor Joule heating in these devices. The Brownian motion of the bead at room temperature is compared with the motion when power is dissipated in the system. This gives an estimate of the temperature increase at a specific location in a microfluidic channel. We demonstrate this method with solutions of different ionic strengths, and establish a precision of 0.9 K and an accuracy of 15%. Furthermore, it is demonstrated that transient heating processes can be monitored with this technique, albeit with a limited time resolution. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Chemistry Lab--Heat Capacity.

ERIC Educational Resources Information Center

Stern, Robert

1998-01-01

Explores measuring the specific heat of a metal ball. The ball is heated to a known temperature then placed in cold water. Students measure the temperature gain of the water in this investigation of the principle of Conservation of Energy. As a second task, students make a precise determination of the density of the ball. (PVD)

A new global anthropogenic heat estimation based on high-resolution nighttime light data

PubMed Central

Yang, Wangming; Luan, Yibo; Liu, Xiaolei; Yu, Xiaoyong; Miao, Lijuan; Cui, Xuefeng

2017-01-01

Consumption of fossil fuel resources leads to global warming and climate change. Apart from the negative impact of greenhouse gases on the climate, the increasing emission of anthropogenic heat from energy consumption also brings significant impacts on urban ecosystems and the surface energy balance. The objective of this work is to develop a new method of estimating the global anthropogenic heat budget and validate it on the global scale with a high precision and resolution dataset. A statistical algorithm was applied to estimate the annual mean anthropogenic heat (AH-DMSP) from 1992 to 2010 at 1×1 km2 spatial resolution for the entire planet. AH-DMSP was validated for both provincial and city scales, and results indicate that our dataset performs well at both scales. Compared with other global anthropogenic heat datasets, the AH-DMSP has a higher precision and finer spatial distribution. Although there are some limitations, the AH-DMSP could provide reliable, multi-scale anthropogenic heat information, which could be used for further research on regional or global climate change and urban ecosystems. PMID:28829436

Development of a laser-induced heat flux technique for measurement of convective heat transfer coefficients in a supersonic flowfield

NASA Technical Reports Server (NTRS)

Porro, A. Robert; Keith, Theo G., Jr.; Hingst, Warren R.; Chriss, Randall M.; Seablom, Kirk D.

1991-01-01

A technique is developed to measure the local convective heat transfer coefficient on a model surface in a supersonic flow field. The technique uses a laser to apply a discrete local heat flux at the model test surface, and an infrared camera system determines the local temperature distribution due to heating. From this temperature distribution and an analysis of the heating process, a local convective heat transfer coefficient is determined. The technique was used to measure the load surface convective heat transfer coefficient distribution on a flat plate at nominal Mach numbers of 2.5, 3.0, 3.5, and 4.0. The flat plate boundary layer initially was laminar and became transitional in the measurement region. The experimental results agreed reasonably well with theoretical predictions of convective heat transfer of flat plate laminar boundary layers. The results indicate that this non-intrusive optical measurement technique has the potential to obtain high quality surface convective heat transfer measurements in high speed flowfields.

Laser based micro forming and assembly.

DOE Office of Scientific and Technical Information (OSTI.GOV)

MacCallum, Danny O'Neill; Wong, Chung-Nin Channy; Knorovsky, Gerald Albert

2006-11-01

It has been shown that thermal energy imparted to a metallic substrate by laser heating induces a transient temperature gradient through the thickness of the sample. In favorable conditions of laser fluence and absorptivity, the resulting inhomogeneous thermal strain leads to a measurable permanent deflection. This project established parameters for laser micro forming of thin materials that are relevant to MESA generation weapon system components and confirmed methods for producing micrometer displacements with repeatable bend direction and magnitude. Precise micro forming vectors were realized through computational finite element analysis (FEA) of laser-induced transient heating that indicated the optimal combination ofmore » laser heat input relative to the material being heated and its thermal mass. Precise laser micro forming was demonstrated in two practical manufacturing operations of importance to the DOE complex: micrometer gap adjustments of precious metal alloy contacts and forming of meso scale cones.« less

Ploidy Manipulation of Zebrafish Embryos with Heat Shock 2 Treatment

PubMed Central

Baars, Destiny L.; Pelegri, Francisco

2016-01-01

Manipulation of ploidy allows for useful transformations, such as diploids to tetraploids, or haploids to diploids. In the zebrafish Danio rerio, specifically the generation of homozygous gynogenetic diploids is useful in genetic analysis because it allows the direct production of homozygotes from a single heterozygous mother. This article describes a modified protocol for ploidy duplication based on a heat pulse during the first cell cycle, Heat Shock 2 (HS2). Through inhibition of centriole duplication, this method results in a precise cell division stall during the second cell cycle. The precise one-cycle division stall, coupled to unaffected DNA duplication, results in whole genome duplication. Protocols associated with this method include egg and sperm collection, UV treatment of sperm, in vitro fertilization and heat pulse to cause a one-cell cycle division delay and ploidy duplication. A modified version of this protocol could be applied to induce ploidy changes in other animal species. PMID:28060351

Infrared Thermal Imaging During Ultrasonic Aspiration of Bone

NASA Astrophysics Data System (ADS)

Cotter, D. J.; Woodworth, G.; Gupta, S. V.; Manandhar, P.; Schwartz, T. H.

Ultrasonic surgical aspirator tips target removal of bone in approaches to tumors or aneurysms. Low profile angled tips provide increased visualization and safety in many high risk surgical situations that commonly were approached using a high speed rotary drill. Utilization of the ultrasonic aspirator for bone removal raised questions about relative amount of local and transmitted heat energy. In the sphenoid wing of a cadaver section, ultrasonic bone aspiration yielded lower thermal rise in precision bone removal than rotary mechanical drills, with maximum temperature of 31 °C versus 69 °C for fluted and 79 °C for diamond drill bits. Mean ultrasonic fragmentation power was about 8 Watts. Statistical studies using tenacious porcine cranium yielded mean power levels of about 4.5 Watts to 11 Watts and mean temperature of less than 41.1 °C. Excessively loading the tip yielded momentary higher power; however, mean thermal rise was less than 8 °C with bone removal starting at near body temperature of about 37 °C. Precision bone removal and thermal management were possible with conditions tested for ultrasonic bone aspiration.

Improved efficiency and precise temperature control of low-frequency induction-heating pure iron vapor source on ECR ion source

NASA Astrophysics Data System (ADS)

Kato, Y.; Takenaka, T.; Yano, K.; Kiriyama, R.; Kurisu, Y.; Nozaki, D.; Muramatsu, M.; Kitagawa, A.; Uchida, T.; Yoshida, Y.; Sato, F.; Iida, T.

2012-11-01

Multiply charged ions to be used prospectively are produced from solid pure material in an electron cyclotron resonance ion source (ECRIS). Recently a pure iron source is also required for the production of caged iron ions in the fullerene in order to control cells in vivo in bio-nano science and technology. We adopt directly heating iron rod by induction heating (IH) because it has non-contact with insulated materials which are impurity gas sources. We choose molybdenum wire for the IH coils because it doesn't need water cooling. To improve power efficiency and temperature control, we propose to the new circuit without previously using the serial and parallel dummy coils (SPD) for matching and safety. We made the circuit consisted of inductively coupled coils which are thin-flat and helix shape, and which insulates the IH power source from the evaporator. This coupling coils circuit, i.e. insulated induction heating coil transformer (IHCT), can be move mechanically. The secondary current can be adjusted precisely and continuously. Heating efficiency by using the IHCT is much higher than those of previous experiments by using the SPD, because leakage flux is decreased and matching is improved simultaneously. We are able to adjust the temperature in heating the vapor source around melting point. And then the vapor pressure can be controlled precisely by using the IHCT. We can control ±10K around 1500°C by this method, and also recognize to controlling iron vapor flux experimentally in the extreme low pressures. Now we come into next stage of developing induction heating vapor source for materials with furthermore high temperature melting points above 2000K with the IHCT, and then apply it in our ECRIS.

Precision chemical heating for diagnostic devices.

PubMed

Buser, J R; Diesburg, S; Singleton, J; Guelig, D; Bishop, J D; Zentner, C; Burton, R; LaBarre, P; Yager, P; Weigl, B H

2015-12-07

Decoupling nucleic acid amplification assays from infrastructure requirements such as grid electricity is critical for providing effective diagnosis and treatment at the point of care in low-resource settings. Here, we outline a complete strategy for the design of electricity-free precision heaters compatible with medical diagnostic applications requiring isothermal conditions, including nucleic acid amplification and lysis. Low-cost, highly energy dense components with better end-of-life disposal options than conventional batteries are proposed as an alternative to conventional heating methods to satisfy the unique needs of point of care use.

Temperature dependency in motor skill learning.

PubMed

Immink, Maarten A; Wright, David L; Barnes, William S

2012-01-01

The present study investigated the role of temperature as a contextual condition for motor skill learning. Precision grip task training occurred while forearm cutaneous temperature was either heated (40-45 °C) or cooled (10-15 °C). At test, temperature was either reinstated or changed. Performance was comparable between training conditions while at test, temperature changes decreased accuracy, especially after hot training conditions. After cold training, temperature change deficits were only evident when concurrent force feedback was presented. These findings are the first evidence of localized temperature dependency in motor skill learning in humans. Results are not entirely accounted for by a context-dependent memory explanation and appear to represent an interaction of neuromuscular and sensory processes with the temperature present during training and test.

Infrared laser-mediated local gene induction in medaka, zebrafish and Arabidopsis thaliana.

PubMed

Deguchi, Tomonori; Itoh, Mariko; Urawa, Hiroko; Matsumoto, Tomohiro; Nakayama, Sohei; Kawasaki, Takashi; Kitano, Takeshi; Oda, Shoji; Mitani, Hiroshi; Takahashi, Taku; Todo, Takeshi; Sato, Junichi; Okada, Kiyotaka; Hatta, Kohei; Yuba, Shunsuke; Kamei, Yasuhiro

2009-12-01

Heat shock promoters are powerful tools for the precise control of exogenous gene induction in living organisms. In addition to the temporal control of gene expression, the analysis of gene function can also require spatial restriction. Recently, we reported a new method for in vivo, single-cell gene induction using an infrared laser-evoked gene operator (IR-LEGO) system in living nematodes (Caenorhabditis elegans). It was demonstrated that infrared (IR) irradiation could induce gene expression in single cells without incurring cellular damage. Here, we report the application of IR-LEGO to the small fish, medaka (Japanese killifish; Oryzias latipes) and zebrafish (Danio rerio), and a higher plant (Arabidopsis thaliana). Using easily observable reporter genes, we successfully induced gene expression in various tissues in these living organisms. IR-LEGO has the potential to be a useful tool in extensive research fields for cell/tissue marking or targeted gene expression in local tissues of small fish and plants.

Instrumentation enabling study of plant physiological response to elevated night temperature

PubMed Central

Mohammed, Abdul R; Tarpley, Lee

2009-01-01

Background Global climate warming can affect functioning of crops and plants in the natural environment. In order to study the effects of global warming, a method for applying a controlled heating treatment to plant canopies in the open field or in the greenhouse is needed that can accept either square wave application of elevated temperature or a complex prescribed diurnal or seasonal temperature regime. The current options are limited in their accuracy, precision, reliability, mobility or cost and scalability. Results The described system uses overhead infrared heaters that are relatively inexpensive and are accurate and precise in rapidly controlling the temperature. Remote computer-based data acquisition and control via the internet provides the ability to use complex temperature regimes and real-time monitoring. Due to its easy mobility, the heating system can randomly be allotted in the open field or in the greenhouse within the experimental setup. The apparatus has been successfully applied to study the response of rice to high night temperatures. Air temperatures were maintained within the set points ± 0.5°C. The incorporation of the combination of air-situated thermocouples, autotuned proportional integrative derivative temperature controllers and phase angled fired silicon controlled rectifier power controllers provides very fast proportional heating action (i.e. 9 ms time base), which avoids prolonged or intense heating of the plant material. Conclusion The described infrared heating system meets the utilitarian requirements of a heating system for plant physiology studies in that the elevated temperature can be accurately, precisely, and reliably controlled with minimal perturbation of other environmental factors. PMID:19519906

Forced-Convection, Liquid-Cooled, Microchannel Heat Sinks

DTIC Science & Technology

1988-01-07

SINK PERFORMANCE 131 5.1 Purpose of the Experimental Investigation 131 5.2 Heat -Sink Fabrication 131 5.2.1 Manufacturing the Microchannels in Indium...the thermal performance of microchannel heat sinks. The methods of microchannel fabrication including precision sawing and orientation-dependent...could be lower than if the microchannel heat sink had been fabricated directly in the back of the IC chip! Figure 4-9 presents the thermal and fluid

Investigation of the influence of groundwater advection on energy extraction rates for sustainable borehole heat exchanger operation

NASA Astrophysics Data System (ADS)

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 < 30 kW) focuses on conductive heat transport as the main energy source while the impact of groundwater flow as the driver for advective heat transport is neglected or strongly simplified. The presented study proves that those simplifications of complex geological and hydrogeological subsurface characteristics are insufficient for a precise evaluation of site-specific energy extraction rates. Based on synthetic model scenarios with varying subsurface conditions (groundwater flow velocity and aquifer thickness) the impact of advection on induced long term temperature changes in 5 and 10 m distance of the borehole heat exchanger is presented. Extending known investigations, this study enhances the evaluation of shallow geothermal energy extraction rates by considering conductive and advective heat transport under varying aquifer thicknesses. Further, it evaluates the impact of advection on installation lengths of the borehole heat exchanger to optimize the initial 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.

Solar-power mountain concept

NASA Technical Reports Server (NTRS)

Clarke, V. C., Jr.

1977-01-01

Solar collectors on mountainside collect thermal energy for mountaintop powerplant. Sloped arrangement reduces heat-transport problem of level ground-based collector field. Heated air rises without mechanical pumps and buoyancy force supplies pumping power without further cost. Precision tracking requirement of power towers eliminated by butted-together Winston-type concentrator troughs. Low-cost native rock is used for heat storage.

Determination of the heat capacities of Lithium/BCX (bromide chloride in thionyl chloride) batteries

NASA Technical Reports Server (NTRS)

Kubow, Stephen A.; Takeuchi, Kenneth J.; Takeuchi, Esther S.

1989-01-01

Heat capacities of twelve different Lithium/BCX (BrCl in thionyl chloride) batteries in sizes AA, C, D, and DD were determined. Procedures and measurement results are reported. The procedure allowed simple, reproducible, and precise determinations of heat capacities of industrially important Lithium/BCX cells, without interfering with performance of the cells. Use of aluminum standards allowed the accuracy of the measurements to be maintained. The measured heat capacities were within 5 percent of calculated heat capacity values.

Geometrical correction factors for heat flux meters

NASA Technical Reports Server (NTRS)

Baumeister, K. J.; Papell, S. S.

1974-01-01

General formulas are derived for determining gage averaging errors of strip-type heat flux meters used in the measurement of one-dimensional heat flux distributions. The local averaging error e(x) is defined as the difference between the measured value of the heat flux and the local value which occurs at the center of the gage. In terms of e(x), a correction procedure is presented which allows a better estimate for the true value of the local heat flux. For many practical problems, it is possible to use relatively large gages to obtain acceptable heat flux measurements.

Development of a Novel Method for the Exploration of the Thermal Response of Superfluid Helium Cooled Superconducting Cables to Pulse Heat Loads

NASA Astrophysics Data System (ADS)

Winkler, T.; Koettig, T.; van Weelderen, R.; Bremer, J.; ter Brake, H. J. M.

Management of transient heat deposition in superconducting magnets and its extraction from the aforementioned is becoming increasingly important to bring high energy particle accelerator performance to higher beam energies and intensities. Precise knowledge of transient heat deposition phenomena in the magnet cables will permit to push the operation of these magnets as close as possible to their current sharing limit, without unduly provoking magnet quenches. With the prospect of operating the Large Hadron Collider at CERN at higher beam energies and intensities an investigation into the response to transient heat loads of LHC magnets, operating in pressurized superfluid helium, is being performed. The more frequently used approach mimics the cable geometry by resistive wires and uses Joule-heating to deposit energy. Instead, to approximate as closely as possible the real magnet conditions, a novel method for depositing heat in cable stacks made out of superconducting magnet-cables has been developed. The goal is to measure the temperature difference as a function of time between the cable stack and the superfluid helium bath depending on heat load and heat pulse length. The heat generation in the superconducting cable and precise measurement of small temperature differences are major challenges. The functional principle and experimental set-up are presented together with proof of principle measurements.

Corkscrew point spread function for far-field three-dimensional nanoscale localization of pointlike objects

PubMed Central

Lew, Matthew D.; Lee, Steven F.; Badieirostami, Majid; Moerner, W. E.

2011-01-01

We describe the corkscrew point spread function (PSF), which can localize objects in three dimensions throughout a 3.2 µm depth of field with nanometer precision. The corkscrew PSF rotates as a function of the axial (z) position of an emitter. Fisher information calculations show that the corkscrew PSF can achieve nanometer localization precision with limited numbers of photons. We demonstrate three-dimensional super-resolution microscopy with the corkscrew PSF by imaging beads on the surface of a triangular polydimethylsiloxane (PDMS) grating. With 99,000 photons detected, the corkscrew PSF achieves a localization precision of 2.7 nm in x, 2.1 nm in y, and 5.7 nm in z. PMID:21263500

Corkscrew point spread function for far-field three-dimensional nanoscale localization of pointlike objects.

PubMed

Lew, Matthew D; Lee, Steven F; Badieirostami, Majid; Moerner, W E

2011-01-15

We describe the corkscrew point spread function (PSF), which can localize objects in three dimensions throughout a 3.2 μm depth of field with nanometer precision. The corkscrew PSF rotates as a function of the axial (z) position of an emitter. Fisher information calculations show that the corkscrew PSF can achieve nanometer localization precision with limited numbers of photons. We demonstrate three-dimensional super-resolution microscopy with the corkscrew PSF by imaging beads on the surface of a triangular polydimethylsiloxane (PDMS) grating. With 99,000 photons detected, the corkscrew PSF achieves a localization precision of 2.7 nm in x, 2.1 nm in y, and 5.7 nm in z.

A method for the measurement of physiologic evaporative water loss.

DOT National Transportation Integrated Search

1963-10-01

The precise measurement of evaporative water loss is essential to an accurate evaluation of this avenue of heat loss in acute and chronic exposures to heat. In psychological studies, the quantitative measurement of palmar sweating plays an equally im...

A scaling law for the local CHF on the external bottom side of a fully submerged reactor vessel

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cheung, F.B.; Haddad, K.H.; Liu, Y.C.

1997-02-01

A scaling law for estimating the local critical heat flux on the outer surface of a heated hemispherical vessel that is fully submerged in water has been developed from the results of an advanced hydrodynamic CHF model for pool boiling on a downward facing curved heating surface. The scaling law accounts for the effects of the size of the vessel, the level of liquid subcooling, the intrinsic properties of the fluid, and the spatial variation of the local critical heat flux along the heating surface. It is found that for vessels with diameters considerably larger than the characteristic size ofmore » the vapor masses, the size effect on the local critical heat flux is limited almost entirely to the effect of subcooling associated with the local liquid head. When the subcooling effect is accounted for separately, the local CHF limit is nearly independent of the vessel size. Based upon the scaling law developed in this work, it is possible to merge, within the experimental uncertainties, all the available local CHF data obtained for various vessel sizes under both saturated and subcooled boiling conditions into a single curve. Applications of the scaling law to commercial-size vessels have been made for various system pressures and water levels above the heated vessel. Over the range of conditions explored in this study, the local CHF limit is found to increase by a factor of two or more from the bottom center to the upper edge of the vessel. Meanwhile, the critical heat flux at a given angular position of the heated vessel is also found to increase appreciably with the system pressure and the water level.« less

Thermoregulatory behavior and orientation preference in bearded dragons.

PubMed

Black, Ian R G; Tattersall, Glenn J

2017-10-01

The regulation of body temperature is a critical function for animals. Although reliant on ambient temperature as a heat source, reptiles, and especially lizards, make use of multiple voluntary and involuntary behaviors to thermoregulate, including postural changes in body orientation, either toward or away from solar sources of heat. This thermal orientation may also result from a thermoregulatory drive to maintain precise control over cranial temperatures or a rostrally-driven sensory bias. The purpose of this work was to examine thermal orientation behavior in adult and neonatal bearded dragons (Pogona vitticeps), to ascertain its prevalence across different life stages within a laboratory situation and its interaction with behavioral thermoregulation. Both adult and neonatal bearded dragons were placed in a thermal gradient and allowed to voluntarily select temperatures for up to 8h to observe the presence and development of a thermoregulatory orientation preference. Both adult and neonatal dragons displayed a non-random orientation, preferring to face toward a heat source while achieving mean thermal preferences of ~ 33-34°C. Specifically, adult dragons were more likely to face a heat source when at cooler ambient temperatures and less likely at warmer temperatures, suggesting that orientation behavior counter-balances local selected temperatures but contributes to their thermoregulatory response. Neonates were also more likely to select cooler temperatures when facing a heat source, but required more experience before this orientation behavior emerged. Combined, these results demonstrate the importance of orientation to behavioral thermoregulation in multiple life stages of bearded dragons. Copyright © 2017 Elsevier Ltd. All rights reserved.

Influence of local topography on precision irrigation management

USDA-ARS?s Scientific Manuscript database

Precision irrigation management is currently accomplished using spatial information about soil properties through soil series maps or electrical conductivity (EC measurements. Crop yield, however, is consistently influenced by local topography, both in rain-fed and irrigated environments. Utilizing ...

Role of buoyant flame dynamics in wildfire spread.

PubMed

Finney, Mark A; Cohen, Jack D; Forthofer, Jason M; McAllister, Sara S; Gollner, Michael J; Gorham, Daniel J; Saito, Kozo; Akafuah, Nelson K; Adam, Brittany A; English, Justin D

2015-08-11

Large wildfires of increasing frequency and severity threaten local populations and natural resources and contribute carbon emissions into the earth-climate system. Although wildfires have been researched and modeled for decades, no verifiable physical theory of spread is available to form the basis for the precise predictions needed to manage fires more effectively and reduce their environmental, economic, ecological, and climate impacts. Here, we report new experiments conducted at multiple scales that appear to reveal how wildfire spread derives from the tight coupling between flame dynamics induced by buoyancy and fine-particle response to convection. Convective cooling of the fine-sized fuel particles in wildland vegetation is observed to efficiently offset heating by thermal radiation until convective heating by contact with flames and hot gasses occurs. The structure and intermittency of flames that ignite fuel particles were found to correlate with instabilities induced by the strong buoyancy of the flame zone itself. Discovery that ignition in wildfires is critically dependent on nonsteady flame convection governed by buoyant and inertial interaction advances both theory and the physical basis for practical modeling.

Role of buoyant flame dynamics in wildfire spread

PubMed Central

Finney, Mark A.; Cohen, Jack D.; Forthofer, Jason M.; McAllister, Sara S.; Gollner, Michael J.; Gorham, Daniel J.; Saito, Kozo; Akafuah, Nelson K.; Adam, Brittany A.; English, Justin D.

2015-01-01

Large wildfires of increasing frequency and severity threaten local populations and natural resources and contribute carbon emissions into the earth-climate system. Although wildfires have been researched and modeled for decades, no verifiable physical theory of spread is available to form the basis for the precise predictions needed to manage fires more effectively and reduce their environmental, economic, ecological, and climate impacts. Here, we report new experiments conducted at multiple scales that appear to reveal how wildfire spread derives from the tight coupling between flame dynamics induced by buoyancy and fine-particle response to convection. Convective cooling of the fine-sized fuel particles in wildland vegetation is observed to efficiently offset heating by thermal radiation until convective heating by contact with flames and hot gasses occurs. The structure and intermittency of flames that ignite fuel particles were found to correlate with instabilities induced by the strong buoyancy of the flame zone itself. Discovery that ignition in wildfires is critically dependent on nonsteady flame convection governed by buoyant and inertial interaction advances both theory and the physical basis for practical modeling. PMID:26183227

Inkjet-Printed Biofunctional Thermo-Plasmonic Interfaces for Patterned Neuromodulation.

PubMed

Kang, Hongki; Lee, Gu-Haeng; Jung, Hyunjun; Lee, Jee Woong; Nam, Yoonkey

2018-02-27

Localized heat generation by the thermo-plasmonic effect of metal nanoparticles has great potential in biomedical engineering research. Precise patterning of the nanoparticles using inkjet printing can enable the application of the thermo-plasmonic effect in a well-controlled way (shape and intensity). However, a universally applicable inkjet printing process that allows good control in patterning and assembly of nanoparticles with good biocompatibility is missing. Here we developed inkjet-printing-based biofunctional thermo-plasmonic interfaces that can modulate biological activities. We found that inkjet printing of plasmonic nanoparticles on a polyelectrolyte layer-by-layer substrate coating enables high-quality, biocompatible thermo-plasmonic interfaces across various substrates (rigid/flexible, hydrophobic/hydrophilic) by induced contact line pinning and electrostatically assisted nanoparticle assembly. We experimentally confirmed that the generated heat from the inkjet-printed thermo-plasmonic patterns can be applied in micrometer resolution over a large area. Lastly, we demonstrated that the patterned thermo-plasmonic effect from the inkjet-printed gold nanorods can selectively modulate neuronal network activities. This inkjet printing process therefore can be a universal method for biofunctional thermo-plasmonic interfaces in various bioengineering applications.

A system for applying rapid warming or cooling stimuli to cells during patch clamp recording or ion imaging.

PubMed

Reid, G; Amuzescu, B; Zech, E; Flonta, M L

2001-10-15

We describe a system for superfusing small groups of cells at a precisely controlled and rapidly adjustable local temperature. Before being applied to the cell or cells under study, solutions are heated or cooled in a chamber of small volume ( approximately 150 microl) and large surface area, sandwiched between four small Peltier elements. The current through the Peltier elements is controlled by a microprocessor using a PID (proportional-integral-derivative) feedback algorithm. The chamber can be heated to at least 60 degrees C and cooled to 0 degrees C, changing its temperature at a maximum rate of about 7 degrees C per second; temperature ramps can be followed under feedback control at up to 4 degrees C per second. Temperature commands can be applied from the digital-to-analogue converter of any laboratory interface or generated digitally by the microprocessor. The peak-to-peak noise contributed by the system does not exceed that contributed by a patch pipette, holder and headstage, making it suitable for single channel as well as whole cell recordings.

Independent Manipulation of Heat and Electrical Current via Bifunctional Metamaterials

NASA Astrophysics Data System (ADS)

Moccia, Massimo; Castaldi, Giuseppe; Savo, Salvatore; Sato, Yuki; Galdi, Vincenzo

2014-04-01

Spatial tailoring of the material constitutive properties is a well-known strategy to mold the local flow of given observables in different physical domains. Coordinate-transformation-based methods (e.g., transformation optics) offer a powerful and systematic approach to design anisotropic, spatially inhomogeneous artificial materials (metamaterials) capable of precisely manipulating wave-based (electromagnetic, acoustic, elastic) as well as diffusion-based (heat) phenomena in a desired fashion. However, as versatile as these approaches have been, most designs have thus far been limited to serving single-target functionalities in a given physical domain. Here, we present a step towards a "transformation multiphysics" framework that allows independent and simultaneous manipulation of multiple physical phenomena. As a proof of principle of this new scheme, we design and synthesize (in terms of realistic material constituents) a metamaterial shell that simultaneously behaves as a thermal concentrator and an electrical "invisibility cloak." Our numerical results open up intriguing possibilities in the largely unexplored phase space of multifunctional metadevices, with a wide variety of potential applications to electrical, magnetic, acoustic, and thermal scenarios.

Testing of active heat sink for advanced high-power laser diodes

NASA Astrophysics Data System (ADS)

Vetrovec, John; Copeland, Drew A.; Feeler, Ryan; Junghans, Jeremy

2011-03-01

We report on the development of a novel active heat sink for high-power laser diodes offering unparalleled capacity in high-heat flux handling and temperature control. The heat sink employs convective heat transfer by a liquid metal flowing at high speed inside a miniature sealed flow loop. Liquid metal flow in the loop is maintained electromagnetically without any moving parts. Thermal conductance of the heat sink is electronically adjustable, allowing for precise control of diode temperature and the laser light wavelength. This paper presents the principles and challenges of liquid metal cooling, and data from testing at high heat flux and high heat loads.

A completely automated flow, heat-capacity, calorimeter for use at high temperatures and pressures

NASA Astrophysics Data System (ADS)

Rogers, P. S. Z.; Sandarusi, Jamal

1990-11-01

An automated, flow calorimeter has been constructed to measure the isobaric heat capacities of concentrated, aqueous electrolyte solutions using a differential calorimetry technique. The calorimeter is capable of operation to 700 K and 40 MPa with a measurement accuracy of 0.03% relative to the heat capacity of the pure reference fluid (water). A novel design encloses the calorimeter within a double set of separately controlled, copper, adiabatic shields that minimize calorimeter heat losses and precisely control the temperature of the inlet fluids. A multistage preheat train, used to efficiently heat the flowing fluid, includes a counter-current heat exchanger for the inlet and outlet fluid streams in tandem with two calorimeter preheaters. Complete system automation is accomplished with a distributed control scheme using multiple processors, allowing the major control tasks of calorimeter operation and control, data logging and display, and pump control to be performed simultaneously. A sophisticated pumping strategy for the two separate syringe pumps allows continuous fluid delivery. This automation system enables the calorimeter to operate unattended except for the reloading of sample fluids. In addition, automation has allowed the development and implementation of an improved heat loss calibration method that provides calorimeter calibration with absolute accuracy comparable to the overall measurement precision, even for very concentrated solutions.

High-Intensity Focused Ultrasound (HIFU) in Localized Prostate Cancer Treatment.

PubMed

Alkhorayef, Mohammed; Mahmoud, Mustafa Z; Alzimami, Khalid S; Sulieman, Abdelmoneim; Fagiri, Maram A

2015-01-01

High-intensity focused ultrasound (HIFU) applies high-intensity focused ultrasound energy to locally heat and destroy diseased or damaged tissue through ablation. This study intended to review HIFU to explain the fundamentals of HIFU, evaluate the evidence concerning the role of HIFU in the treatment of prostate cancer (PC), review the technologies used to perform HIFU and the published clinical literature regarding the procedure as a primary treatment for PC. Studies addressing HIFU in localized PC were identified in a search of internet scientific databases. The analysis of outcomes was limited to journal articles written in English and published between 2000 and 2013. HIFU is a non-invasive approach that uses a precisely delivered ultrasound energy to achieve tumor cell necrosis without radiation or surgical excision. In current urological oncology, HIFU is used clinically in the treatment of PC. Clinical research on HIFU therapy for localized PC began in the 1990s, and the majority of PC patients were treated with the Ablatherm device. HIFU treatment for localized PC can be considered as an alternative minimally invasive therapeutic modality for patients who are not candidates for radical prostatectomy. Patients with lower pre-HIFU PSA level and favourable pathologic Gleason score seem to present better oncologic outcomes. Future advances in technology and safety will undoubtedly expand the HIFU role in this indication as more of patient series are published, with a longer follow-up period.

A new test procedure to evaluate the performance of substations for collective heating systems

NASA Astrophysics Data System (ADS)

Baetens, Robin; Verhaert, Ivan

2017-11-01

The overall heat demand of a single dwelling, existing out of space heating and domestic hot water production, decreases due to higher insulation rates. Because of this, investing in efficient and renewable heat generation becomes less interesting. Therefore, to incorporate renewables or residual heat on a larger scale, district heating or collective heating systems grow in importance. Within this set-up, the substation is responsible for the interaction between local demand for comfort and overall energy performance of the collective heating system. Many different configurations of substations exist, which influence both local comfort and central system performance. Next to that, also hybrids exist with additional local energy input. To evaluate performance of such substations, a new experimental-based test procedure is developed in order to evaluate these different aspects, characterized by the two roles a substation has, namely as heat generator and as heat consumer. The advantage of this approach is that an objective comparison between individual and central systems regarding performance on delivering local comfort can be executed experimentally. The lab set-up consists out of three different subsystems, namely the central system, the domestic hot water consumption and the local space heating. The central system can work with different temperature regimes and control strategies, as these aspects have proven to have the largest influence on actual performance. The domestic hot water system is able to generate similar tap profiles according to eco-design regulation for domestic hot water generation. The space heating system is able to demand a modular heat load.

Opportunities and Challenges for Personal Heat Exposure Research

PubMed Central

Kuras, Evan R.; Richardson, Molly B.; Calkins, Miriam M.; Ebi, Kristie L.; Hess, Jeremy J.; Kintziger, Kristina W.; Jagger, Meredith A.; Middel, Ariane; Scott, Anna A.; Spector, June T.; Uejio, Christopher K.; Vanos, Jennifer K.; Zaitchik, Benjamin F.; Gohlke, Julia M.

2017-01-01

Background: Environmental heat exposure is a public health concern. The impacts of environmental heat on mortality and morbidity at the population scale are well documented, but little is known about specific exposures that individuals experience. Objectives: The first objective of this work was to catalyze discussion of the role of personal heat exposure information in research and risk assessment. The second objective was to provide guidance regarding the operationalization of personal heat exposure research methods. Discussion: We define personal heat exposure as realized contact between a person and an indoor or outdoor environment that poses a risk of increases in body core temperature and/or perceived discomfort. Personal heat exposure can be measured directly with wearable monitors or estimated indirectly through the combination of time–activity and meteorological data sets. Complementary information to understand individual-scale drivers of behavior, susceptibility, and health and comfort outcomes can be collected from additional monitors, surveys, interviews, ethnographic approaches, and additional social and health data sets. Personal exposure research can help reveal the extent of exposure misclassification that occurs when individual exposure to heat is estimated using ambient temperature measured at fixed sites and can provide insights for epidemiological risk assessment concerning extreme heat. Conclusions: Personal heat exposure research provides more valid and precise insights into how often people encounter heat conditions and when, where, to whom, and why these encounters occur. Published literature on personal heat exposure is limited to date, but existing studies point to opportunities to inform public health practice regarding extreme heat, particularly where fine-scale precision is needed to reduce health consequences of heat exposure. https://doi.org/10.1289/EHP556 PMID:28796630

Operations Studies of the Gyrotrons on DIII-D

NASA Astrophysics Data System (ADS)

Storment, Stephen; Lohr, John; Cengher, Mirela; Gorelov, Yuri; Ponce, Dan; Torrezan, Antonio

2017-10-01

The gyrotrons are high power vacuum tubes used in fusion research to provide high power density heating and current drive in precisely localized areas of the plasma. Despite the increasing experience with both the manufacture and operation of these devices, individual gyrotrons with similar design and manufacturing processes can exhibit important operational differences in terms of generated rf power, efficiency and lifetime. This report discusses differences in the performance of several gyrotrons in operation at DIII-D and presents the results of a series of measurements that could lead to improved the performance of single units based on a better understanding of the causes of these differences. The rf power generation efficiency can be different from gyrotron to gyrotron. In addition, the power loading of the collector can feature localized hot spots, where the collector can locally be close to the power deposition limits. Measurements of collector power loading provide maps of the power deposition and can provide understanding of the effect of modulation of the output rf beam on the total loading, leading to improved operational rules increasing the safety margins for the gyrotrons under different operational scenarios. Work supported by US DOE under DE-FC02-04ER54698.

Laser Annealing on the Surface Treatment of Thin Super Elastic NiTi Wire

NASA Astrophysics Data System (ADS)

Samal, S.; Heller, L.; Brajer, J.; Tyc, O.; Kadrevek, L.; Sittner, P.

2018-05-01

Here the aim of this research is annealing the surface of NiTi wire for shape memory alloy, super-elastic wire by solid state laser beam. The laser surface treatment was carried out on the NiTi wire locally with fast, selective, surface heat treatment that enables precisely tune the localized material properties without any precipitation. Both as drawn (hard) and straight annealing NiTi wire were considered for laser annealing with input power 3 W, with precisely focusing the laser beam height 14.3 % of the Z-axis with a spot size of 1 mm. However, straight annealing wire is more interest due to its low temperature shape setting behavior and used by companies for stent materials. The variable parameter such as speed of the laser scanning and tensile stress on the NiTi wire were optimized to observe the effect of laser response on the sample. Superelastic, straight annealed NiTi wires (d: 0.10 mm) were held prestrained at the end of the superelastic plateau (ε: 5 ∼6.5 %) above the superelastic region by a tensile machine ( Mitter: miniature testing rig) at room temperature (RT). Simultaneously, the hardness of the wires along the cross-section was performed by nano-indentation (NI) method. The hardness of the NiTi wire corresponds to phase changes were correlated with NI test. The laser induced NiTi wire shows better fatigue performance with improved 6500 cycles.

Radio-Frequency Illuminated Superconductive Disks: Reverse Josephson Effects and Implications for Precise Measuring of Proposed Gravity Effects

NASA Technical Reports Server (NTRS)

Noever, David A.; Koczor, Ronald J.

1998-01-01

We have previously reported results using a high precision gravimeter to probe local gravity changes in the neighborhood of large bulk-processed high-temperature superconductors. It have been indicated three essential components to achieve anomalous gravity effects, namely large, two-layer high-temperature YBCO superconductors, magnetic levitation and AC input in the form of radio-frequency (RF) electromagnetic fields. We report experiments on RF-illuminated (1-15 MHz) superconducting disks with corresponding gravity readings indicating an apparent increase in observed gravity of approximately 3-5 x l0(exp -5)cm/sq s, above and to the side of the superconductor. In this preliminary study, RF- illumination is achieved using a series of large radius (15 cm) spiral antenna with RF power inputs equal to or greater than 90 W. The observed gravitational modification range is significantly lower than the 2.1% gravity modification. The error analyses of thermal and electromagnetic interference in a magnetically shielded gravimeter with vacuum enclosures, Faraday cages and shielded instrument leads, are outlined both experimentally and theoretically. The nearly exact correspondence between the peak gravity effects reported and the well-known peak in AC resistance in superconductors (2-7 MHz, owing to reverse Josephson quantum effects) suggests that electrical resistance will arise in this frequency range and subsequently any trapped magnetic fields in the superconductor may disperse partially into the measuring instrument's local environment. Implications for propulsion initiatives and RF-heating in superconductors will be discussed.

A numerical study of EGS heat extraction process based on a thermal non-equilibrium model for heat transfer in subsurface porous heat reservoir

NASA Astrophysics Data System (ADS)

Chen, Jiliang; Jiang, Fangming

2016-02-01

With a previously developed numerical model, we perform a detailed study of the heat extraction process in enhanced or engineered geothermal system (EGS). This model takes the EGS subsurface heat reservoir as an equivalent porous medium while it considers local thermal non-equilibrium between the rock matrix and the fluid flowing in the fractured rock mass. The application of local thermal non-equilibrium model highlights the temperature-difference heat exchange process occurring in EGS reservoirs, enabling a better understanding of the involved heat extraction process. The simulation results unravel the mechanism of preferential flow or short-circuit flow forming in homogeneously fractured reservoirs of different permeability values. EGS performance, e.g. production temperature and lifetime, is found to be tightly related to the flow pattern in the reservoir. Thermal compensation from rocks surrounding the reservoir contributes little heat to the heat transmission fluid if the operation time of an EGS is shorter than 15 years. We find as well the local thermal equilibrium model generally overestimates EGS performance and for an EGS with better heat exchange conditions in the heat reservoir, the heat extraction process acts more like the local thermal equilibrium process.

New laser machining processes for shape memory alloys

NASA Astrophysics Data System (ADS)

Haferkamp, Heinz; Paschko, Stefan; Goede, Martin

2001-04-01

Due to special material properties, shape memory alloys (SMA) are finding increasing attention in micro system technology. However, only a few processes are available for the machining of miniaturized SMA-components. In this connection, laser material processing offers completely new possibilities. This paper describes the actual status of two projects that are being carried out to qualify new methods to machine SMA components by means of laser radiation. Within one project, the laser material ablation process of miniaturized SMA- components using ultra-short laser pulses (pulse duration: approx. 200 fs) in comparison to conventional laser material ablation is being investigated. Especially for SMA micro- sensors and actuators, it is important to minimize the heat affected zone (HAZ) to maintain the special mechanical properties. Light-microscopic investigations of the grain texture of SMA devices processed with ultra-short laser pulses show that the HAZ can be neglected. Presently, the main goal of the project is to qualify this new processing technique for the micro-structuring of complex SMA micro devices with high precision. Within a second project, investigations are being carried out to realize the induction of the two-way memory effect (TWME) into SMA components using laser radiation. By precisely heating SMA components with laser radiation, local tensions remain near the component surface. In connection with the shape memory effect, these tensions can be used to make the components execute complicated movements. Compared to conventional training methods to induce the TWME, this procedure is faster and easier. Furthermore, higher numbers of thermal cycling are expected because of the low dislocation density in the main part of the component.

Automated Solvent Seaming of Large Polyimide Membranes

NASA Technical Reports Server (NTRS)

Rood, Robert; Moore, James D.; Talley, Chris; Gierow, Paul A.

2006-01-01

A solvent-based welding process enables the joining of precise, cast polyimide membranes at their edges to form larger precise membranes. The process creates a homogeneous, optical-quality seam between abutting membranes, with no overlap and with only a very localized area of figure disturbance. The seam retains 90 percent of the strength of the parent material. The process was developed for original use in the fabrication of wide-aperture membrane optics, with areal densities of less than 1 kg/m2, for lightweight telescopes, solar concentrators, antennas, and the like to be deployed in outer space. The process is just as well applicable to the fabrication of large precise polyimide membranes for flat or inflatable solar concentrators and antenna reflectors for terrestrial applications. The process is applicable to cast membranes made of CP1 (or equivalent) polyimide. The process begins with the precise fitting together and fixturing of two membrane segments. The seam is formed by applying a metered amount of a doped solution of the same polyimide along the abutting edges of the membrane segments. After the solution has been applied, the fixtured films are allowed to dry and are then cured by convective heating. The weld material is the same as the parent material, so that what is formed is a homogeneous, strong joint that is almost indistinguishable from the parent material. The success of the process is highly dependent on formulation of the seaming solution from the correct proportion of the polyimide in a suitable solvent. In addition, the formation of reliable seams depends on the deposition of a precise amount of the seaming solution along the seam line. To ensure the required precision, deposition is performed by use of an automated apparatus comprising a modified commercially available, large-format, ink-jet print head on an automated positioning table. The printing head jets the seaming solution into the seam area at a rate controlled in coordination with the movement of the positioning table.

The role of local heating in the 2015 Indian heat wave

USDA-ARS?s Scientific Manuscript database

India faced a major heat wave during the summer of 2015. Temperature anomalies peaked in the dry period before the onset of the summer monsoon, suggesting that local land-atmosphere feedbacks involving desiccated soils and vegetation might have played a role in driving the heat extreme. Upon examina...

A Heat Warning System to Reduce Heat Illness in San Diego County

NASA Astrophysics Data System (ADS)

Tardy, A. O.; Corcus, I.; Guirguis, K.; Gershunov, A.; Basu, R.; Stepanski, B.

2016-12-01

The National Weather Service (NWS) has issued official heat alerts to the public and decision making partners for many years by developing a single criterion or regional criteria from heat indices which combine temperature and humidity. The criteria have typically relied on fixed thresholds and did not consider impact from a particular heat episode, nor did it factor seasonality, population acclimatization, or impacts on the most vulnerable subgroups. In 2013, the NWS San Diego office began modifying their criteria to account for local climatology with much less dependence on humidity or the heat index. These local changes were based on initial findings from the California Department of Public Health, EpiCenter California Injury Data Online system (EPIC), which document heat health impacts. The Scripps Institution of Oceanography (SIO) in collaboration with the California Environmental Protection Agency's Office of Environmental Health Hazard Assessment and the NWS completed a study of hospital visits during heat waves in California showing significant health impacts occurred in the past when no regional heat warning was issued. Therefore, the results supported the need for an exploratory project to implement significant modification of the traditional local criteria. To understand the impacts of heat on community health, medical outcome data were provided by the County of San Diego Emergency Medical Services Branch (EMS), which is provided by the County's Public Health Officer to monitor heat-related illness and injury daily during specific heat episodes. The data were combined with SIO research to inform the modification of local NWS heat criteria and establish trigger points to pilot new procedures for the issuance of heat alerts. Finally, procedures were customized for each of the county health departments in the NWS area of responsibility across extreme southwest California counties in collaboration with their Office of Emergency Services (OES). The collaboration was the development of a local Heat Health Impact and Public Notification System prototype. This system incorporates better temperature thresholds defined relative to local climate, levels of heat related responses and activation, as well as a standardized alerting terminology for public notifications.

Diode Laser Ear Piercing: A Novel Technique.

PubMed

Suseela, Bibilash Babu; Babu, Preethitha; Chittoria, Ravi Kumar; Mohapatra, Devi Prasad

2016-01-01

Earlobe piercing is a common office room procedure done by a plastic surgeon. Various methods of ear piercing have been described. In this article, we describe a novel method of laser ear piercing using the diode laser. An 18-year-old female patient underwent an ear piercing using a diode laser with a power of 2.0 W in continuous mode after topical local anaesthetic and pre-cooling. The diode laser was fast, safe, easy to use and highly effective way of ear piercing. The advantages we noticed while using the diode laser over conventional methods were more precision, minimal trauma with less chances of hypertrophy and keloids, no bleeding with coagulation effect of laser, less time taken compared to conventional method and less chance of infection due to thermal heat effect of laser.

Processing of Bulk YBa2Cu3O(7-x) High Temperature Superconductor Materials for Gravity Modification Experiments and Performance Under AC Levitation

NASA Technical Reports Server (NTRS)

Koczor, Ronald; Noever, David; Hiser, Robert

1999-01-01

We have previously reported results using a high precision gravimeter to probe local gravity changes in the neighborhood of bulk-processed high temperature superconductor disks. Others have indicated that large annular disks (on the order of 25cm diameter) and AC levitation fields play an essential role in their observed experiments. We report experiments in processing such large bulk superconductors. Successful results depend on material mechanical characteristics, and pressure and heat treat protocols. Annular disks having rough dimensions of 30cm O.D., 7cm I.D. and 1 cm thickness have been routinely fabricated and tested under AC levitation fields ranging from 45 to 300OHz. Implications for space transportation initiatives and power storage flywheel technology will be discussed.

Improved Noninterferometric Test of Collapse Models Using Ultracold Cantilevers

NASA Astrophysics Data System (ADS)

Vinante, A.; Mezzena, R.; Falferi, P.; Carlesso, M.; Bassi, A.

2017-09-01

Spontaneous collapse models predict that a weak force noise acts on any mechanical system, as a consequence of the collapse of the wave function. Significant upper limits on the collapse rate have been recently inferred from precision mechanical experiments, such as ultracold cantilevers and the space mission LISA Pathfinder. Here, we report new results from an experiment based on a high-Q cantilever cooled to millikelvin temperatures, which is potentially able to improve the current bounds on the continuous spontaneous localization (CSL) model by 1 order of magnitude. High accuracy measurements of the cantilever thermal fluctuations reveal a nonthermal force noise of unknown origin. This excess noise is compatible with the CSL heating predicted by Adler. Several physical mechanisms able to explain the observed noise have been ruled out.

Fuel Composition and Performance Analysis of Endothermically Heated Fuels for Pulse Detonation Engines

DTIC Science & Technology

2009-03-01

Waste heat from a pulse detonation engine (PDE) was extracted via concentric, counter flow heat exchangers to produce supercritical pyrolytic...mass spectrometry HLPC = High performance liquid chromatography NPT = National pipe thread PAH = Polycyclic aromatic hydrocarbon PDE = Pulse...Precision Liquid Chromatography (HPLC). The resulting “stressed” fuel showed a 29 shift to lower molecular weight compounds, as well as the production

High Efficiency Coupling of Optical Fibres with SU8 Micro-droplet Using Laser Welding Process

NASA Astrophysics Data System (ADS)

Yardi, Seema; Gupta, Ankur; Sundriyal, Poonam; Bhatt, Geeta; Kant, Rishi; Boolchandani, D.; Bhattacharya, Shantanu

2016-09-01

Apart from micro- structure fabrication, ablation, lithography etc., lasers find a lot of utility in various areas like precision joining, device fabrication, local heat delivery for surface texturing and local change of microstructure fabrication of standalone optical micro-devices (like microspheres, micro-prisms, micro-scale ring resonators, optical switches etc). There is a wide utility of such systems in chemical/ biochemical diagnostics and also communications where the standalone optical devices exist at a commercial scale but chip based devices with printed optics are necessary due to coupling issues between printed structures and external optics. This paper demonstrates a novel fabrication strategy used to join standalone optical fibres to microchip based printed optics using a simple SU8 drop. The fabrication process is deployed for fiber to fiber optical coupling and coupling between fiber and printed SU-8 waveguides. A CO2 laser is used to locally heat the coupling made up of SU8 material. Optimization of various dimensional parameters using design of experiments (DOE) on the bonded assembly has been performed as a function of laser power, speed, cycle control, spot size so on so forth. Exclusive optical [RF] modelling has been performed to estimate the transmissibility of the optical fibers bonded to each other on a surface with SU8. Our studies indicate the formation of a Whispering gallery mode (WGM) across the micro-droplet leading to high transmissibility of the signal. Through this work we have thus been able to develop a method of fabrication for optical coupling of standalone fibers or coupling of on-chip optics with off-chip illumination/detection.

Development of a radiative heating facility for studying flow and heat transfer in hydrocarbon-cooled structures

NASA Astrophysics Data System (ADS)

Dong, Da; Lu, Yang; Yuan, Yueming; Fan, Xuejun

2018-06-01

An experimental facility was designed to simulate the heat exchange between the hot gas and the fuel-cooled wall in a scramjet combustor. Thermal radiation from an electrically heated graphite plate is employed to unilaterally heat up a multi-channeled cooling plate. A maximum heat flux of over 0.8 MW/m2 was achieved for an effective heating area up to 1000 mm × 40 mm. Precise control of the back pressure of a coolant (up to 5 MPa) in a unique way was also demonstrated. With this facility, studies of flow and heat transfer in hydrocarbon-cooled structures can be performed under a well-controlled manner.

[Value of the space perception test for evaluation of the aptitude for precision work in geodesy].

PubMed

Remlein-Mozolewska, G

1982-01-01

The visual spatial localization ability of geodesy and cartography - employers and of the pupils trained for the mentioned profession has been examined. The examination has been based on work duration and the time of its performance. A correlation between the localization ability and the precision of the hand - movements required in everyday work has been proven. The better the movement precision, the more efficient the visual spatial localization. The length of work has not been significant. The test concerned appeared to be highly useful in geodesy for qualifying workers for the posts requiring good hands efficiency.

Global and local Joule heating effects seen by DE 2

NASA Technical Reports Server (NTRS)

Heelis, R. A.; Coley, W. R.

1988-01-01

In the altitude region between 350 and 550 km, variations in the ion temperature principally reflect similar variations in the local frictional heating produced by a velocity difference between the ions and the neutrals. Here, the distribution of the ion temperature in this altitude region is shown, and its attributes in relation to previous work on local Joule heating rates are discussed. In addition to the ion temperature, instrumentation on the DE 2 satellite also provides a measure of the ion velocity vector representative of the total electric field. From this information, the local Joule heating rate is derived. From an estimate of the height-integrated Pedersen conductivity it is also possible to estimate the global (height-integrated) Joule heating rate. Here, the differences and relationships between these various parameters are described.

Preventing heat-related morbidity and mortality: new approaches in a changing climate.

PubMed

O'Neill, Marie S; Carter, Rebecca; Kish, Jonathan K; Gronlund, Carina J; White-Newsome, Jalonne L; Manarolla, Xico; Zanobetti, Antonella; Schwartz, Joel D

2009-10-20

Due to global climate change, the world will, on average, experience a higher number of heat waves, and the intensity and length of these heat waves is projected to increase. Knowledge about the implications of heat exposure to human health is growing, with excess mortality and illness occurring during hot weather in diverse regions. Certain groups, including the elderly, the urban poor, and those with chronic health conditions, are at higher risk. Preventive actions include: establishing heat wave warning systems; making cool environments available (through air conditioning or other means); public education; planting trees and other vegetation; and modifying the built environment to provide proper ventilation and use materials and colors that reduce heat build-up and optimize thermal comfort. However, to inspire local prevention activities, easily understood information about the strategies' benefits needs to be incorporated into decision tools. Integrating heat health information into a comprehensive adaptation planning process can alert local decision-makers to extreme heat risks and provide information necessary to choose strategies that yield the largest health improvements and cost savings. Tools to enable this include web-based programs that illustrate effective methods for including heat health in comprehensive local-level adaptation planning; calculate costs and benefits of several activities; maps showing zones of high potential heat exposure and vulnerable populations in a local area; and public awareness materials and training for implementing preventive activities. A new computer-based decision tool will enable local estimates of heat-related health effects and potential savings from implementing a range of prevention strategies.

Heat localization for targeted tumor treatment with nanoscale near-infrared radiation absorbers

PubMed Central

Xie, Bin; Singh, Ravi; Torti, F. M.; Keblinski, Pawel; Torti, Suzy

2012-01-01

Focusing heat delivery while minimizing collateral damage to normal tissues is essential for successful nanoparticle-mediated laser-induced thermal cancer therapy. We present thermal maps obtained via magnetic resonance imaging (MRI) characterizing laser heating of a phantom tissue containing a multiwalled carbon nanotube inclusion. The data demonstrate that heating continuously over tens of seconds leads to poor localization (~ 0.5 cm) of the elevated temperature region. By contrast, for the same energy input, heat localization can be reduced to the millimeter rather than centimeter range by increasing the laser power and shortening the pulse duration. The experimental data can be well understood within a simple diffusive heat conduction model. Analysis of the model indicates that to achieve 1 mm or better resolution, heating pulses of ~ 2s or less need to be used with appropriately higher heating power. Modeling these data using a diffusive heat conduction analysis predicts parameters for optimal targeted delivery of heat for ablative therapy. PMID:22948207

A Mechanism for Recent Production of Liquid Water on Mars

NASA Technical Reports Server (NTRS)

Hecht, M. H.; Bridges, N. T.

2003-01-01

Though Mars is a cold, dry planet, with respect to the thermal stability of liquid water at low altitudes it is not terribly different from comparably cold places on Earth. In dry air such water would evaporate faster on Mars, at a rate comparable to a 60 C hot spring on Earth, but the heat loss associated with that evaporation would be mitigated by the poor thermal convection in the thin Martian air. Even at higher altitudes where the atmospheric pressure does not reach the triple point of water, liquid water might theoretically exist in a low-vapor pressure form such as wet soil, in a briny solution, or simply under a layer of dust or snow. The theoretical stability of liquid water does not suggest its occurrence, either on Mars or in Antarctica. In fact, global models have suggested that locations capable of providing sufficient heat for melting are, precisely for that reason, too dry for water to be present. However, the temperature of irregular local structures such as trenches or craters can be markedly warmer than those of the uniform surfaces of global models. The work described here suggests a plausible scenario in which seasonal liquid water might be produced locally, in sheltered locations, through a process of condensation, cold-trapping, buffering, and melting. While the amounts produced in the present climate would be small, copious amounts of meltwater may have been produced at other phases of the orbital cycle, as recently as 20,000 years ago.

Innovative Way to Test Batteries Fills a Market Niche | News | NREL

Science.gov Websites

researchers, performs precise thermal measurements needed to design safer, longer-lasting, and more cost NREL researchers, are capable of performing the precise thermal measurements needed to make safer . Batteries cannot survive heat, and they need thermal management; IBCs are essential in measuring how much

Holographic heat current as Noether current

NASA Astrophysics Data System (ADS)

Liu, Hai-Shan; Lü, H.; Pope, C. N.

2017-09-01

We employ the Noether procedure to derive a general formula for the radially conserved heat current in AdS planar black holes with certain transverse and traceless perturbations, for a general class of gravity theories. For Einstein gravity, the general higher-order Lovelock gravities and also a class of Horndeski gravities, we derive the boundary stress tensor and show that the resulting boundary heat current matches precisely the bulk Noether current.

High-precision two-dimensional atom localization from four-wave mixing in a double-Λ four-level atomic system

NASA Astrophysics Data System (ADS)

Shui, Tao; Yang, Wen-Xing; Chen, Ai-Xi; Liu, Shaopeng; Li, Ling; Zhu, Zhonghu

2018-03-01

We propose a scheme for high-precision two-dimensional (2D) atom localization via the four-wave mixing (FWM) in a four-level double-Λ atomic system. Due to the position-dependent atom-field interaction, the 2D position information of the atoms can be directly determined by the measurement of the normalized light intensity of output FWM-generated field. We further show that, when the position-dependent generated FWM field has become sufficiently intense, efficient back-coupling to the FWM generating state becomes important. This back-coupling pathway leads to competitive multiphoton destructive interference of the FWM generating state by three supplied and one internally generated fields. We find that the precision of 2D atom localization can be improved significantly by the multiphoton destructive interference and depends sensitively on the frequency detunings and the pump field intensity. Interestingly enough, we show that adjusting the frequency detunings and the pump field intensity can modify significantly the FWM efficiency, and consequently lead to a redistribution of the atoms. As a result, the atom can be localized in one of four quadrants with holding the precision of atom localization.

A Low Cost Sensors Approach for Accurate Vehicle Localization and Autonomous Driving Application.

PubMed

Vivacqua, Rafael; Vassallo, Raquel; Martins, Felipe

2017-10-16

Autonomous driving in public roads requires precise localization within the range of few centimeters. Even the best current precise localization system based on the Global Navigation Satellite System (GNSS) can not always reach this level of precision, especially in an urban environment, where the signal is disturbed by surrounding buildings and artifacts. Laser range finder and stereo vision have been successfully used for obstacle detection, mapping and localization to solve the autonomous driving problem. Unfortunately, Light Detection and Ranging (LIDARs) are very expensive sensors and stereo vision requires powerful dedicated hardware to process the cameras information. In this context, this article presents a low-cost architecture of sensors and data fusion algorithm capable of autonomous driving in narrow two-way roads. Our approach exploits a combination of a short-range visual lane marking detector and a dead reckoning system to build a long and precise perception of the lane markings in the vehicle's backwards. This information is used to localize the vehicle in a map, that also contains the reference trajectory for autonomous driving. Experimental results show the successful application of the proposed system on a real autonomous driving situation.

A Low Cost Sensors Approach for Accurate Vehicle Localization and Autonomous Driving Application

PubMed Central

Vassallo, Raquel

2017-01-01

Autonomous driving in public roads requires precise localization within the range of few centimeters. Even the best current precise localization system based on the Global Navigation Satellite System (GNSS) can not always reach this level of precision, especially in an urban environment, where the signal is disturbed by surrounding buildings and artifacts. Laser range finder and stereo vision have been successfully used for obstacle detection, mapping and localization to solve the autonomous driving problem. Unfortunately, Light Detection and Ranging (LIDARs) are very expensive sensors and stereo vision requires powerful dedicated hardware to process the cameras information. In this context, this article presents a low-cost architecture of sensors and data fusion algorithm capable of autonomous driving in narrow two-way roads. Our approach exploits a combination of a short-range visual lane marking detector and a dead reckoning system to build a long and precise perception of the lane markings in the vehicle’s backwards. This information is used to localize the vehicle in a map, that also contains the reference trajectory for autonomous driving. Experimental results show the successful application of the proposed system on a real autonomous driving situation. PMID:29035334

The chloroplast-localized small heat shock protein Hsp21 associates with the thylakoid membranes in heat-stressed plants.

PubMed

Bernfur, Katja; Rutsdottir, Gudrun; Emanuelsson, Cecilia

2017-09-01

The small heat shock protein (sHsp) chaperones are crucial for cell survival and can prevent aggregation of client proteins that partially unfold under destabilizing conditions. Most investigations on the chaperone activity of sHsps are based on a limited set of thermosensitive model substrate client proteins since the endogenous targets are often not known. There is a high diversity among sHsps with a single conserved β-sandwich fold domain defining the family, the α-crystallin domain, whereas the N-terminal and C-terminal regions are highly variable in length and sequence among various sHsps and conserved only within orthologues. The endogenous targets are probably also varying among various sHsps, cellular compartments, cell type and organism. Here we have investigated Hsp21, a non-metazoan sHsp expressed in the chloroplasts in green plants which experience huge environmental fluctuations not least in temperature. We describe how Hsp21 can also interact with the chloroplast thylakoid membranes, both when isolated thylakoid membranes are incubated with Hsp21 protein and when plants are heat-stressed. The amount of Hsp21 associated with the thylakoid membranes was precisely determined by quantitative mass spectrometry after metabolic 15 N-isotope labeling of either recombinantly expressed and purified Hsp21 protein or intact Arabidopsis thaliana plants. We found that Hsp21 is among few proteins that become associated with the thylakoid membranes in heat-stressed plants, and that approximately two thirds of the pool of chloroplast Hsp21 is affected. We conclude that for a complete picture of the role of sHsps in plant stress resistance also their association with the membranes should be considered. © 2017 The Authors Protein Science published by Wiley Periodicals, Inc. on behalf of The Protein Society.

High precision localization of intracerebral hemorrhage based on 3D MPR on head CT images

NASA Astrophysics Data System (ADS)

Sun, Jianyong; Hou, Xiaoshuai; Sun, Shujie; Zhang, Jianguo

2017-03-01

The key step for minimally invasive intracerebral hemorrhage surgery is precisely positioning the hematoma location in the brain before and during the hematoma surgery, which can significantly improves the success rate of puncture hematoma. We designed a 3D computerized surgical plan (CSP) workstation precisely to locate brain hematoma based on Multi-Planar Reconstruction (MPR) visualization technique. We used ten patients' CT/MR studies to verify our designed CSP intracerebral hemorrhage localization method. With the doctor's assessment and comparing with the results of manual measurements, the output of CSP WS for hematoma surgery is more precise and reliable than manual procedure.

Multi-Channel RF System for MRI-Guided Transurethral Ultrasound Thermal Therapy

NASA Astrophysics Data System (ADS)

Yak, Nicolas; Asselin, Matthew; Chopra, Rajiv; Bronskill, Michael

2009-04-01

MRI-guided transurethral ultrasound thermal therapy is an approach to treating localized prostate cancer which targets precise deposition of thermal energy within a confined region of the gland. This treatment requires a system incorporating a heating applicator with multiple planar ultrasound transducers and associated RF electronics to control individual elements independently in order to achieve accurate 3D treatment. We report the design, construction, and characterization of a prototype multi-channel system capable of controlling 16 independent RF signals for a 16-element heating applicator. The main components are a control computer, microcontroller, and a 16-channel signal generator with 16 amplifiers, each incorporating a low-pass filter and transmitted/reflected power detection circuit. Each channel can deliver from 0.5 to 10 W of electrical power and good linearity from 3 to 12 MHz. Harmonic RF signals near the Larmor frequency of a 1.5 T MRI were measured to be below -30 dBm and heating experiments within the 1.5 T MR system showed no significant decrease in SNR of the temperature images. The frequency and power for all 16 channels could be changed in less than 250 ms, which was sufficiently rapid for proper performance of the control algorithms. A common backplane design was chosen which enabled an inexpensive, modular approach for each channel resulting in an overall system with minimal footprint.

Temperature control and measurement with tunable femtosecond optical tweezers

NASA Astrophysics Data System (ADS)

Mondal, Dipankar; Goswami, Debabrata

2016-09-01

We present the effects of wavelength dependent temperature rise in a femtosecond optical tweezers. Our experiments involve the femtosecond trapping laser tunable from 740-820 nm at low power 25 mW to cause heating in the trapped volume within a homogeneous solution of sub micro-molar concentration of IR dye. The 780 nm high repetition rate laser acts as a resonant excitation source which helps to create the local heating effortlessly within the trapping volume. We have used both position autocorrelation and equipartion theorem to evaluate temperature at different wavelength having different absorption coefficient. Fixing the pulse width in the temporal domain gives constant bandwidth at spatial domain, which makes our system behave as a tunable temperature rise device with high precision. This observation leads us to calculate temperature as well as viscosity within the vicinity of the trapping zone. A mutual energy transfer occurs between the trapped bead and solvents that leads to transfer the thermal energy of solvents into the kinetic energy of the trap bead and vice-versa. Thus hot solvated molecules resulting from resonant and near resonant excitation of trapping wavelength can continuously dissipate heat to the trapped bead which will be reflected on frequency spectrum of Brownian noise exhibited by the bead. Temperature rise near the trapping zone can significantly change the viscosity of the medium. We observe temperature rise profile according to its Gaussian shaped absorption spectrum with different wavelength.

A New Heat Supply System of Cogeneration for the Local Community

NASA Astrophysics Data System (ADS)

Yamaguchi, Hideki; Hisazumi, Yoshinori; Asano, Hitoshi; Morita, Hikaru; Hori, Toshihiro; Matsumoto, Toshiki; Abiko, Tetsuo

In order for economically viable distributed generation systems for local communities to be widely accepted, it is essential to develop an efficient and low-cost heat supply system. For this purpose, we propose a new heat supply system which we already presented at the ICOPE-05 Chicago. The key technology for the system is to connect compact heat supply units with a heat storage function installed in all the households of the local community, such as condominiums, by a single-loop of hot water pipe. A phase change material was used for the heat supply unit as the heat storage material. However, for easier handling and reducing the cost of the unit, we have developed a new heat supply unit whose heat storage tank is made of plastic. Hot water for space heating is used as the heat storage material. Further we constructed a heat supply system for 7 lived-in households with a 5 kW gas engine and a 42 kW boiler as the heat sources. Some experiments with a heat supply unit and a heat supply system, such as for heat storage and heat supply for peak demand were conducted. Additionally, dynamic simulations of heat demand by 50 households and a COP evaluation of a new CO2 heat pump system using low-temperature exhaust gas from the gas engine were also conducted.

Local Heat Transfer for Finned-Tube Heat Exchangers using Oval Tubes

DOE Office of Scientific and Technical Information (OSTI.GOV)

O'Brien, James Edward; Sohal, Manohar Singh

2000-08-01

This paper presents the results of an experimental study of forced convection heat transfer in a narrow rectangular duct fitted with either a circular tube or an elliptical tube in crossflow. The duct was designed to simulate a single passage in a fin-tube heat exchanger. Heat transfer measurements were obtained using a transient technique in which a heated airflow is suddenly introduced to the test section. High-resolution local fin-surface temperature distributions were obtained at several times after initiation of the transient using an imaging infrared camera. Corresponding local fin-surface heat transfer coefficient distributions were then calculated from a locally appliedmore » one-dimensional semi-infinite inverse heat conduction model. Heat transfer results were obtained over an airflow rate ranging from 1.56 x 10-3 to 15.6 x 10-3 kg/s. These flow rates correspond to a duct-height Reynolds number range of 630 – 6300 with a duct height of 1.106 cm and a duct width-toheight ratio, W/H, of 11.25. The test cylinder was sized such that the diameter-to-duct height ratio, D/H is 5. The elliptical tube had an aspect ratio of 3:1 and a/H equal to 4.33. Results presented in this paper reveal visual and quantitative details of local fin-surface heat transfer distributions in the vicinity of circular and oval tubes and their relationship to the complex horseshoe vortex system that forms in the flow stagnation region. Fin surface stagnation-region Nusselt numbers are shown to be proportional to the square-root of Reynolds number.« less

Mechanical stability of a microscope setup working at a few kelvins for single-molecule localization

NASA Astrophysics Data System (ADS)

Hinohara, Takuya; Hamada, Yuki I.; Nakamura, Ippei; Matsushita, Michio; Fujiyoshi, Satoru

2013-06-01

A great advantage of single-molecule fluorescence imaging is the localization precision of molecule beyond the diffraction limit. Although longer signal-acquisition yields higher precision, acquisition time at room temperature is normally limited by photobleaching, thermal diffusion, and so on. At low temperature of a few kelvins, much longer acquisition is possible and will improve precision if the sample and the objective are held stably enough. The present work examined holding stability of the sample and objective at 1.5 K in superfluid helium in the helium bath. The stability was evaluated by localization precision of a point scattering source of a polymer bead. Scattered light was collected by the objective, and imaged by a home-built rigid imaging unit. The standard deviation of the centroid position determined for 800 images taken continuously in 17 min was 0.5 nm in the horizontal and 0.9 nm in the vertical directions.

Method for localizing heating in tumor tissue

DOEpatents

Doss, James D.; McCabe, Charles W.

1977-04-12

A method for a localized tissue heating of tumors is disclosed. Localized radio frequency current fields are produced with specific electrode configurations. Several electrode configurations are disclosed, enabling variations in electrical and thermal properties of tissues to be exploited.

Time-multiplexed two-channel capacitive radiofrequency hyperthermia with nanoparticle mediation.

PubMed

Kim, Ki Soo; Hernandez, Daniel; Lee, Soo Yeol

2015-10-24

Capacitive radiofrequency (RF) hyperthermia suffers from excessive temperature rise near the electrodes and poorly localized heat transfer to the deep-seated tumor region even though it is known to have potential to cure ill-conditioned tumors. To better localize heat transfer to the deep-seated target region in which electrical conductivity is elevated by nanoparticle mediation, two-channel capacitive RF heating has been tried on a phantom. We made a tissue-mimicking phantom consisting of two compartments, a tumor-tissue-mimicking insert against uniform background agarose. The tumor-tissue-mimicking insert was made to have higher electrical conductivity than the normal-tissue-mimicking background by applying magnetic nanoparticle suspension to the insert. Two electrode pairs were attached on the phantom surface by equal-angle separation to apply RF electric field to the phantom. To better localize heat transfer to the tumor-tissue-mimicking insert, RF power with a frequency of 26 MHz was delivered to the two channels in a time-multiplexed way. To monitor the temperature rise inside the phantom, MR thermometry was performed at a 3T MRI intermittently during the RF heating. Finite-difference-time-domain (FDTD) electromagnetic and thermal simulations on the phantom model were also performed to verify the experimental results. As compared to the one-channel RF heating, the two-channel RF heating with time-multiplexed driving improved the spatial localization of heat transfer to the tumor-tissue-mimicking region in both the simulation and experiment. The two-channel RF heating also reduced the temperature rise near the electrodes significantly. Time-multiplexed two-channel capacitive RF heating has the capability to better localize heat transfer to the nanoparticle-mediated tumor region which has higher electrical conductivity than the background normal tissues.

Development of a fully-consistent reduced order model to study instabilities in boiling water reactors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dykin, V.; Demaziere, C.

2012-07-01

A simple nonlinear Reduced Order Model to study global, regional and local instabilities in Boiling Water Reactors is described. The ROM consists of three submodels: neutron-kinetic, thermal-hydraulic and heat-transfer models. The neutron-kinetic model allows representing the time evolution of the three first neutron kinetic modes: the fundamental, the first and the second azimuthal modes. The thermal-hydraulic model describes four heated channels in order to correctly simulate out-of-phase behavior. The coupling between the different submodels is performed via both void and Doppler feedback mechanisms. After proper spatial homogenization, the governing equations are discretized in the time-domain. Several modifications, compared to othermore » existing ROMs, have been implemented, and are reported in this paper. One novelty of the ROM is the inclusion of both azimuthal modes, which allows to study combined instabilities (in-phase and out-of-phase), as well as to investigate the corresponding interference effects between them. The second modification concerns the precise estimation of so-called reactivity coefficients or C{sub mn}{sup *V,D} - coefficients by using direct cross-section data from SIMULATE-3 combined with the CORE SIM core simulator in order to calculate Eigenmodes. Furthermore, a non-uniform two-step axial power profile is introduced to simulate the separate heat production in the single and two-phase regions, respectively. An iterative procedure was developed to calculate the solution to the coupled neutron-kinetic/thermal-hydraulic static problem prior to solving the time-dependent problem. Besides, the possibility of taking into account the effect of local instabilities is demonstrated in a simplified manner. The present ROM is applied to the investigation of an actual instability that occurred at the Swedish Forsmark-1 BWR in 1996/1997. The results generated by the ROM are compared with real power plant measurements performed during stability tests and show a good qualitative agreement. The present study provides some insight in a deeper understanding of the physical principles which drive both core-wide and local instabilities. (authors)« less

Nanoscale steady-state temperature gradients within polymer nanocomposites undergoing continuous-wave photothermal heating from gold nanorods.

PubMed

Maity, Somsubhra; Wu, Wei-Chen; Tracy, Joseph B; Clarke, Laura I; Bochinski, Jason R

2017-08-17

Anisotropically-shaped metal nanoparticles act as nanoscale heaters via excitation of a localized surface plasmon resonance, utilizing a photothermal effect which converts the optical energy into local heat. Steady-state temperatures within a polymer matrix embedded with gold nanorods undergoing photothermal heating using continuous-wave excitation are measured in the immediate spatial vicinity of the nanoparticle (referred to as the local temperature) from observing the rate of physical rotation of the asymmetric nanoparticles within the locally created polymer melt. Average temperatures across the entire (mostly solid) sample (referred to as the global temperature) are simultaneously observed using a fluorescence method from randomly dispersed molecular emitters. Comparing these two independent measurements in films having varying concentrations of nanorods reveals the interplay between the local and global temperatures, clearly demonstrating the capability of these material samples to sustain large steady-state spatial temperature gradients when experiencing continuous-wave excitation photothermal heating. These results are discussed quantitatively. Illustrative imaging studies of nanofibers under photothermal heating also support the presence of a large temperature gradient. Photothermal heating in this manner has potential utility in creating unique thermal processing conditions for outcomes such as driving chemical reactions, inducing crystallinity changes, or enhancing degradation processes in a manner unachievable by conventional heating methods.

Application of Thin-Film Thermocouples to Localized Heat Transfer Measurements

NASA Technical Reports Server (NTRS)

Lepicovsky, J.; Bruckner, R. J.; Smith, F. A.

1995-01-01

The paper describes a proof-of-concept experiment on thin-film thermocouples used for localized heat transfer measurements applicable to experiments on hot parts of turbine engines. The paper has three main parts. The first part describes the thin-film sensors and manufacturing procedures. Attention is paid to connections between thin-film thermocouples and lead wires, which has been a source of problems in the past. The second part addresses the test arrangement and facility used for the heat transfer measurements modeling the conditions for upcoming warm turbine tests at NASA LeRC. The paper stresses the advantages of a modular approach to the test rig design. Finally, we present the results of bulk and local heat flow rate measurements, as well as overall heat transfer coefficients obtained from measurements in a narrow passage with an aspect ratio of 11.8. The comparison of bulk and local heat flow rates confirms applicability of thin-film thermocouples to upcoming warm turbine tests.

76 FR 77939 - Proposed Provision of Navigation Services for the Next Generation Air Transportation System...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-12-15

... navigation for en route through non-precision instrument approaches. GPS is an internationally accepted... Localizer Performance with Vertical guidance (LPV). These approaches are equivalent to Category I ILS, but... approach procedures with LPV or localizer performance (LP) non-precision lines of minima to all qualified...

High-Intensity Focused Ultrasound (HIFU) in Localized Prostate Cancer Treatment

PubMed Central

Alkhorayef, Mohammed; Mahmoud, Mustafa Z.; Alzimami, Khalid S.; Sulieman, Abdelmoneim; Fagiri, Maram A.

2015-01-01

Summary Background High-intensity focused ultrasound (HIFU) applies high-intensity focused ultrasound energy to locally heat and destroy diseased or damaged tissue through ablation. This study intended to review HIFU to explain the fundamentals of HIFU, evaluate the evidence concerning the role of HIFU in the treatment of prostate cancer (PC), review the technologies used to perform HIFU and the published clinical literature regarding the procedure as a primary treatment for PC. Material/Methods Studies addressing HIFU in localized PC were identified in a search of internet scientific databases. The analysis of outcomes was limited to journal articles written in English and published between 2000 and 2013. Results HIFU is a non-invasive approach that uses a precisely delivered ultrasound energy to achieve tumor cell necrosis without radiation or surgical excision. In current urological oncology, HIFU is used clinically in the treatment of PC. Clinical research on HIFU therapy for localized PC began in the 1990s, and the majority of PC patients were treated with the Ablatherm device. Conclusions HIFU treatment for localized PC can be considered as an alternative minimally invasive therapeutic modality for patients who are not candidates for radical prostatectomy. Patients with lower pre-HIFU PSA level and favourable pathologic Gleason score seem to present better oncologic outcomes. Future advances in technology and safety will undoubtedly expand the HIFU role in this indication as more of patient series are published, with a longer follow-up period. PMID:25806099

High-precision laser microcutting and laser microdrilling using diffractive beam-splitting and high-precision flexible beam alignment

NASA Astrophysics Data System (ADS)

Zibner, F.; Fornaroli, C.; Holtkamp, J.; Shachaf, Lior; Kaplan, Natan; Gillner, A.

2017-08-01

High-precision laser micro machining gains more importance in industrial applications every month. Optical systems like the helical optics offer highest quality together with controllable and adjustable drilling geometry, thus as taper angle, aspect ratio and heat effected zone. The helical optics is based on a rotating Dove-prism which is mounted in a hollow shaft engine together with other optical elements like wedge prisms and plane plates. Although the achieved quality can be interpreted as extremely high the low process efficiency is a main reason that this manufacturing technology has only limited demand within the industrial market. The objective of the research studies presented in this paper is to dramatically increase process efficiency as well as process flexibility. During the last years, the average power of commercial ultra-short pulsed laser sources has increased significantly. The efficient utilization of the high average laser power in the field of material processing requires an effective distribution of the laser power onto the work piece. One approach to increase the efficiency is the application of beam splitting devices to enable parallel processing. Multi beam processing is used to parallelize the fabrication of periodic structures as most application only require a partial amount of the emitted ultra-short pulsed laser power. In order to achieve highest flexibility while using multi beam processing the single beams are diverted and re-guided in a way that enables the opportunity to process with each partial beam on locally apart probes or semimanufactures.

Laminar mixed convective heat transfer enhancement by using Ag-TiO2-water hybrid Nanofluid in a heated horizontal annulus

NASA Astrophysics Data System (ADS)

Benkhedda, Mohamed; Boufendi, Toufik; Touahri, S.

2018-03-01

In the present paper, laminar mixed convection in horizontal annulus filled with a TiO2/water nanofluid and Ag-TiO2/water hybrid nanofluid has been numerically studied. The outer cylinder is uniformly heated while the inner cylinder is adiabatic. The governing equations with the appropriate boundary conditions are discretized by the finite volume method with second order precision, and solved by using the SIMPLER and Thomas algorithms. The numerical simulations are performed for various nanoparticles volume fractions, between 0 and 8% and Grashof numbers between 105 and 106. The results shows that for all studied Grashof numbers, the local and average Nusselt numbers, and the bulk temperature increase with the increasing of the volume fraction and the Grashof number. The heat transfer is very enhancement when using a Ag-TiO2/water hybrid nanofluid compared to the similar TiO2/water nanofluid. Moreover, the exploitation of the numerical results that we obtained enabled us to develop two new correlations, which allow the estimation of the average Nusselt number. The results reveal that the numerical data are in a good agreement with the correlation data. The maximum error for nanofluid and hybrid nanofluid was around 2.5% and 4.7% respectively. Hence, among the multitude of the obtained results in this work, it remains that the new correlations developed, especially for the hybrid nanofluid Ag-TiO2 / water, constitute for their originality, the most significant result of this research.

The role of size polydispersity in magnetic fluid hyperthermia: average vs. local infra/over-heating effects.

PubMed

Munoz-Menendez, Cristina; Conde-Leboran, Ivan; Baldomir, Daniel; Chubykalo-Fesenko, Oksana; Serantes, David

2015-11-07

An efficient and safe hyperthermia cancer treatment requires the accurate control of the heating performance of magnetic nanoparticles, which is directly related to their size. However, in any particle system the existence of some size polydispersity is experimentally unavoidable, which results in a different local heating output and consequently a different hyperthermia performance depending on the size of each particle. With the aim to shed some light on this significant issue, we have used a Monte Carlo technique to study the role of size polydispersity in heat dissipation at both the local (single particle) and global (macroscopic average) levels. We have systematically varied size polydispersity, temperature and interparticle dipolar interaction conditions, and evaluated local heating as a function of these parameters. Our results provide a simple guide on how to choose, for a given polydispersity degree, the more adequate average particle size so that the local variation in the released heat is kept within some limits that correspond to safety boundaries for the average-system hyperthermia performance. All together we believe that our results may help in the design of more effective magnetic hyperthermia applications.

Antagonism of soluble guanylyl cyclase attenuates cutaneous vasodilation during whole body heat stress and local warming in humans

PubMed Central

Zhao, Joan L.; Wu, Yubo; Johnson, John M.

2011-01-01

We hypothesized that nitric oxide activation of soluble guanylyl cyclase (sGC) participates in cutaneous vasodilation during whole body heat stress and local skin warming. We examined the effects of the sGC inhibitor, 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ), on reflex skin blood flow responses to whole body heat stress and on nonreflex responses to increased local skin temperature. Blood flow was monitored by laser-Doppler flowmetry, and blood pressure by Finapres to calculate cutaneous vascular conductance (CVC). Intradermal microdialysis was used to treat one site with 1 mM ODQ in 2% DMSO and Ringer, a second site with 2% DMSO in Ringer, and a third site received Ringer. In protocol 1, after a period of normothermia, whole body heat stress was induced. In protocol 2, local heating units warmed local skin temperature from 34 to 41°C to cause local vasodilation. In protocol 1, in normothermia, CVC did not differ among sites [ODQ, 15 ± 3% maximum CVC (CVCmax); DMSO, 14 ± 3% CVCmax; Ringer, 17 ± 6% CVCmax; P > 0.05]. During heat stress, ODQ attenuated CVC increases (ODQ, 54 ± 4% CVCmax; DMSO, 64 ± 4% CVCmax; Ringer, 63 ± 4% CVCmax; P < 0.05, ODQ vs. DMSO or Ringer). In protocol 2, at 34°C local temperature, CVC did not differ among sites (ODQ, 17 ± 2% CVCmax; DMSO, 18 ± 4% CVCmax; Ringer, 18 ± 3% CVCmax; P > 0.05). ODQ attenuated CVC increases at 41°C local temperature (ODQ, 54 ± 5% CVCmax; DMSO, 86 ± 4% CVCmax; Ringer, 90 ± 2% CVCmax; P < 0.05 ODQ vs. DMSO or Ringer). sGC participates in neurogenic active vasodilation during heat stress and in the local response to direct skin warming. PMID:21292837

Experience with Geared Propeller Drives for Aviation Engines

NASA Technical Reports Server (NTRS)

Kutzbach, K

1920-01-01

I. The development of the gear wheels: (a) bending stresses; (b) compressive stresses; (c) heating; (d) precision of manufacture. II. General arrangement of the gearing. III. Vibration in the shaft transmission. An overview is given of experience with geared propeller drives for aviation engines. The development of gear wheels is discussed with emphasis upon bending stresses, compressive stresses, heating, and precision in manufacturing. With respect to the general arrangement of gear drives for airplanes, some principal rules of mechanical engineering that apply with special force are noted. The primary vibrations in the shaft transmission are discussed. With respect to vibration, various methods for computing vibration frequency and the influence of elastic couplings are discussed.

Optimal Placement of Non-Intrusive Waste Heat Recovery Devices in Exhaust Ducts

DTIC Science & Technology

2015-06-01

Reynolds Number and Local Reynolds Number Depression Mixing .............................................................................40  3...57  viii 1.  Counterintuitive Findings Due to Local Reynolds Number Depression ... depression in the secondary recirculation zone enhances heat transfer, and device placement is the dominant factor for maximizing heat transfer in a

Measuring true localization accuracy in super resolution microscopy with DNA-origami nanostructures

NASA Astrophysics Data System (ADS)

Reuss, Matthias; Fördős, Ferenc; Blom, Hans; Öktem, Ozan; Högberg, Björn; Brismar, Hjalmar

2017-02-01

A common method to assess the performance of (super resolution) microscopes is to use the localization precision of emitters as an estimate for the achieved resolution. Naturally, this is widely used in super resolution methods based on single molecule stochastic switching. This concept suffers from the fact that it is hard to calibrate measures against a real sample (a phantom), because true absolute positions of emitters are almost always unknown. For this reason, resolution estimates are potentially biased in an image since one is blind to true position accuracy, i.e. deviation in position measurement from true positions. We have solved this issue by imaging nanorods fabricated with DNA-origami. The nanorods used are designed to have emitters attached at each end in a well-defined and highly conserved distance. These structures are widely used to gauge localization precision. Here, we additionally determined the true achievable localization accuracy and compared this figure of merit to localization precision values for two common super resolution microscope methods STED and STORM.

Accounting for Limited Detection Efficiency and Localization Precision in Cluster Analysis in Single Molecule Localization Microscopy

PubMed Central

Shivanandan, Arun; Unnikrishnan, Jayakrishnan; Radenovic, Aleksandra

2015-01-01

Single Molecule Localization Microscopy techniques like PhotoActivated Localization Microscopy, with their sub-diffraction limit spatial resolution, have been popularly used to characterize the spatial organization of membrane proteins, by means of quantitative cluster analysis. However, such quantitative studies remain challenged by the techniques’ inherent sources of errors such as a limited detection efficiency of less than 60%, due to incomplete photo-conversion, and a limited localization precision in the range of 10 – 30nm, varying across the detected molecules, mainly depending on the number of photons collected from each. We provide analytical methods to estimate the effect of these errors in cluster analysis and to correct for them. These methods, based on the Ripley’s L(r) – r or Pair Correlation Function popularly used by the community, can facilitate potentially breakthrough results in quantitative biology by providing a more accurate and precise quantification of protein spatial organization. PMID:25794150

Measurement of local high-level, transient surface heat flux

NASA Technical Reports Server (NTRS)

Liebert, Curt H.

1988-01-01

This study is part of a continuing investigation to develop methods for measuring local transient surface heat flux. A method is presented for simultaneous measurements of dual heat fluxes at a surface location by considering the heat flux as a separate function of heat stored and heat conducted within a heat flux gage. Surface heat flux information is obtained from transient temperature measurements taken at points within the gage. Heat flux was determined over a range of 4 to 22 MW/sq m. It was concluded that the method is feasible. Possible applications are for heat flux measurements on the turbine blade surfaces of space shuttle main engine turbopumps and on the component surfaces of rocket and advanced gas turbine engines and for testing sensors in heat flux gage calibrators.

A Study on Infrared Local Heat Treatment for AA5083 to Improve Formability and Automotive Part Forming

NASA Astrophysics Data System (ADS)

Lee, Eun-Ho; Yang, Dong-Yol; Ko, SeJin

2017-10-01

Automotive industries are increasingly employing aluminum alloys for auto parts to reduce vehicle weight. However, the low formability of aluminum alloys has been an obstacle to their application. To resolve the formability problem, some studies involving heat treatments under laboratory conditions have been reported. However, for industrial applications, the heat treatment sequence, heating energy efficiency, and a commercial part test should be studied. This work shows an infrared (IR) local heat treatment, heating only small areas where the heat treatment is required, for an aluminum alloy to improve the formability with a reduction of heating energy. The experiment shows that the formability drastically increases when the aluminum alloy is heat treated between two forming stages, referred to as intermediate heat treatment. The microstructures of the test pieces are evaluated to identify the cause of the increase in the formability. For an industrial application, an aluminum tailgate, which cannot be manufactured without heat treatment, was successfully manufactured by the IR local heat treatment with a reduction of energy. A simulation was also conducted with a stress-based forming limit diagram, which is not affected by the strain path and heat treatment histories. The simulation gives a good prediction of the formability improvement.

Heat Transfer Enhancement for Finned-tube Heat Exchangers with Winglets

DOE Office of Scientific and Technical Information (OSTI.GOV)

O'Brien, James Edward; Sohal, Manohar Singh

2000-11-01

This paper presents the results of an experimental study of forced convection heat transfer in a narrow rectangular duct fitted with a circular tube and/or a delta-winglet pair. The duct was designed to simulate a single passage in a fin-tube heat exchanger. Heat transfer measurements were obtained using a transient technique in which a heated airflow is suddenly introduced to the test section. High-resolution local fin-surface temperature distributions were obtained at several times after initiation of the transient using an imaging infrared camera. Corresponding local fin-surface heat transfer coefficient distributions were then calculated from a locally applied one-dimensional semi-infinite inversemore » heat conduction model. Heat transfer results were obtained over an airflow rate ranging from 1.51 x 10-3 to 14.0 x 10-3 kg/s. These flow rates correspond to a duct-height Reynolds number range of 670 – 6300 with a duct height of 1.106 cm and a duct width-toheight ratio, W/H, of 11.25. The test cylinder was sized such that the diameter-to-duct height ratio, D/H is 5. Results presented in this paper reveal visual and quantitative details of local fin-surface heat transfer distributions in the vicinity of a circular tube, a delta-winglet pair, and a combination of a circular tube and a delta-winglet pair. Comparisons of local and average heat transfer distributions for the circular tube with and without winglets are provided. Overall mean finsurface Nusselt-number results indicate a significant level of heat transfer enhancement associated with the deployment of the winglets with the circular cylinder. At the lowest Reynolds numbers (which correspond to the laminar operating conditions of existing geothermal air-cooled condensers), the enhancement level is nearly a factor of two. At higher Reynolds numbers, the enhancement level is close to 50%.« less

Numerical simulations and parameterizations of volcanic plumes observed at Reunion Island

NASA Astrophysics Data System (ADS)

Gurwinder Sivia, Sandra; Gheusi, Francois; Mari, Celine; DiMuro, Andrea; Tulet, Pierre

2013-04-01

Volcanoes are natural composite hazards. The volcanic ejecta can have considerable impact on human health. Volcanic gases and ash, can be especially harmful to people with lung disease such as asthma. Volcanic gases that pose the greatest potential hazards are sulfur dioxide, carbon dioxide, and hydrogen fluoride. Locally, sulfur dioxide gas can lead to acid rain and air pollution downwind from a volcano. These gases can come from lava flows as well as volcano eruptive plumes. This acidic pollution can be transported by wind over large distances. To comply with regulatory rules, modeling tools are needed to accurately predict the contribution of volcanic emissions to air quality degradation. Unfortunately, the ability of existing models to simulate volcanic plume production and dispersion is currently limited by inaccurate volcanic emissions and uncertainties in plume-rise estimates. The present work is dedicated to the study of deep injections of volcanic emissions into the troposphere developed as consequence of intense but localized input of heat near eruptive mouths. This work covers three aspects. First a precise quantification of heat sources in terms of surface, geometry and heat source intensity is done for the Piton de la Fournaise volcano. Second, large eddy simulation (LES) are performed with the Meso-NH model to determine the dynamics and vertical development of volcanic plumes. The estimated energy fluxes and the geometry of the heat source is used at the bottom boundary to generate and sustain the plume, while, passive tracers are used to represent volcanic gases and their injection into the atmosphere. The realism of the simulated plumes is validated on the basis of plume observations. The LES simulations finally serve as references for the development of column parameterizations for the coarser resolution version of the model which is the third aspect of the present work. At spatial resolution coarser than ~1km, buoyant volcanic plumes are sub-grid processes. A new parameterization for the injection height is presented which is based on a modified version of the eddy-diffusivity/mass-flux scheme initially developed for the simulation of convective boundary layer.

The effect of dry spots on heat transfer in a locally heated liquid film moving under the action of gas flow in a channel

NASA Astrophysics Data System (ADS)

Zaitsev, D. V.; Tkachenko, E. M.; Bykovskaya, E. F.

2017-11-01

Intensive evaporation of a thin liquid film, moving in a flat micro-/minichannel under the action of gas flow is very promising for the use in cooling systems of modern semiconductor devices with localized heat sources of high intensity. In this work, using the high-speed visualization, the effect of the formation of dry spots on heat transfer in a locally heated liquid film shear-driven in a channel was investigated. It was found that the maximum intensity of heat removal from the heater is achieved in the mode, when the film flow continuity is broken. During the experiment the total area of dry spots increases with increasing heat flux and heater temperature, but when the heater reaches a certain temperature (≈100°C), the total area begins to decrease. However, the length of contact line increases with increasing heat flux and reaches a maximum in the pre-crisis regime. Intensive evaporation in the region of the contact line may explain the achievement of high heat fluxes in the shear-driven liquid film.

Coolant-side heat-transfer rates for a hydrogen-oxygen rocket and a new technique for data correlation

NASA Technical Reports Server (NTRS)

Schacht, R. L.; Quentmeyer, R. J.

1973-01-01

An experimental investigation was conducted to determine the coolant-side, heat transfer coefficients for a liquid cooled, hydrogen-oxygen rocket thrust chamber. Heat transfer rates were determined from measurements of local hot gas wall temperature, local coolant temperature, and local coolant pressure. A correlation incorporating an integration technique for the transport properties needed near the pseudocritical temperature of liquid hydrogen gives a satisfactory prediction of hot gas wall temperatures.

Two-dimensional heat flow apparatus

NASA Astrophysics Data System (ADS)

McDougall, Patrick; Ayars, Eric

2014-06-01

We have created an apparatus to quantitatively measure two-dimensional heat flow in a metal plate using a grid of temperature sensors read by a microcontroller. Real-time temperature data are collected from the microcontroller by a computer for comparison with a computational model of the heat equation. The microcontroller-based sensor array allows previously unavailable levels of precision at very low cost, and the combination of measurement and modeling makes for an excellent apparatus for the advanced undergraduate laboratory course.

The characterization of neural tissue ablation rate and corresponding heat affected zone of a 2 micron Tm3+ doped fiber laser(Conference Presentation)

NASA Astrophysics Data System (ADS)

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.

Development and experimental qualification of a calculation scheme for the evaluation of gamma heating in experimental reactors. Application to MARIA and Jules Horowitz (JHR) MTR Reactors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tarchalski, M.; Pytel, K.; Wroblewska, M.

2015-07-01

Precise computational determination of nuclear heating which consists predominantly of gamma heating (more than 80 %) is one of the challenges in material testing reactor exploitation. Due to sophisticated construction and conditions of experimental programs planned in JHR it became essential to use most accurate and precise gamma heating model. Before the JHR starts to operate, gamma heating evaluation methods need to be developed and qualified in other experimental reactor facilities. This is done inter alia using OSIRIS, MINERVE or EOLE research reactors in France. Furthermore, MARIA - Polish material testing reactor - has been chosen to contribute to themore » qualification of gamma heating calculation schemes/tools. This reactor has some characteristics close to those of JHR (beryllium usage, fuel element geometry). To evaluate gamma heating in JHR and MARIA reactors, both simulation tools and experimental program have been developed and performed. For gamma heating simulation, new calculation scheme and gamma heating model of MARIA have been carried out using TRIPOLI4 and APOLLO2 codes. Calculation outcome has been verified by comparison to experimental measurements in MARIA reactor. To have more precise calculation results, model of MARIA in TRIPOLI4 has been made using the whole geometry of the core. This has been done for the first time in the history of MARIA reactor and was complex due to cut cone shape of all its elements. Material composition of burnt fuel elements has been implemented from APOLLO2 calculations. An experiment for nuclear heating measurements and calculation verification has been done in September 2014. This involved neutron, photon and nuclear heating measurements at selected locations in MARIA reactor using in particular Rh SPND, Ag SPND, Ionization Chamber (all three from CEA), KAROLINA calorimeter (NCBJ) and Gamma Thermometer (CEA/SCK CEN). Measurements were done in forty points using four channels. Maximal nuclear heating evaluated from measurements is of the order of 2.5 W/g at half of the possible MARIA power - 15 MW. The approach and the detailed program for experimental verification of calculations will be presented. The following points will be discussed: - Development of a gamma heating model of MARIA reactor with TRIPOLI 4 (coupled neutron-photon mode) and APOLLO2 model taking into account the key parameters like: configuration of the core, experimental loading, control rod location, reactor power, fuel depletion); - Design of specific measurement tools for MARIA experiments including for instance a new single-cell calorimeter called KAROLINA calorimeter; - MARIA experimental program description and a preliminary analysis of results; - Comparison of calculations for JHR and MARIA cores with experimental verification analysis, calculation behavior and n-γ 'environments'. (authors)« less

Localized temperature and chemical reaction control in nanoscale space by nanowire array.

PubMed

Jin, C Yan; Li, Zhiyong; Williams, R Stanley; Lee, K-Cheol; Park, Inkyu

2011-11-09

We introduce a novel method for chemical reaction control with nanoscale spatial resolution based on localized heating by using a well-aligned nanowire array. Numerical and experimental analysis shows that each individual nanowire could be selectively and rapidly Joule heated for local and ultrafast temperature modulation in nanoscale space (e.g., maximum temperature gradient 2.2 K/nm at the nanowire edge; heating/cooling time < 2 μs). By taking advantage of this capability, several nanoscale chemical reactions such as polymer decomposition/cross-linking and direct and localized hydrothermal synthesis of metal oxide nanowires were demonstrated.

Estimating the Total Heat Flux from the ASHES Hydrothermal Vent Field Using the Sentry Autonomous Underwater Vehicle

NASA Astrophysics Data System (ADS)

Crone, T. J.; Kinsey, J. C.; Mittelstaedt, E. L.

2017-12-01

Hydrothermal venting at mid-ocean ridges influences ocean chemistry, the thermal and chemical structure of the oceanic crust, and the evolution of unique and diverse autolithotrophically-supported ecosystems. Axially-hosted hydrothermal systems are responsible for 20-25% of the total heat flux out of Earth's interior, and likely play a large role in local as well as global biogeochemical cycles. Despite the importance of these systems, only a few studies have attempted to constrain the volume and heat flux of an entire hydrothermal vent field. In July of 2014 we used the Sentry autonomous underwater vehicle (AUV) to survey the water column over the ASHES hydrothermal vent field which is located within the caldera of Axial Seamount, an active submarine volcano located on the Juan de Fuca Ridge. To estimate the total heat and mass flux from this vent field, we equipped Sentry with a Nortek acoustic Doppler velocimeter (ADV), an inertial measurement unit (IMU), two acoustic Doppler current profilers (ADCPs), and two SBE3 temperature probes, allowing us to obtain precise measurements of fluid temperature and water velocity. The survey was designed using a control volume approach in which Sentry was pre-programmed to survey a 150-m-square centered over the vent field flying a grid pattern with 5-m track line spacing followed by a survey of the perimeter. This pattern was repeated multiple times during several 10-h dives at different altitudes, including 10, 20, 40, and 60 m above the seafloor, and during one 40-h survey at an altitude of 10 m. During the 40-h survey, the pattern was repeated nine times allowing us to obtain observations over several tidal cycles. Water velocity data obtained with Sentry were corrected for platform motion and then combined with the temperature measurements to estimate heat flux. The analysis of these data will likely provide the most accurate and highest resolution heat and mass flux estimates at a seafloor hydrothermal field to date.

Effect of gage size on the measurement of local heat flux. [formulas for determining gage averaging errors

NASA Technical Reports Server (NTRS)

Baumeister, K. J.; Papell, S. S.

1973-01-01

General formulas are derived for determining gage averaging errors of strip-type heat flux meters used in the measurement of one-dimensional heat flux distributions. In addition, a correction procedure is presented which allows a better estimate for the true value of the local heat flux. As an example of the technique, the formulas are applied to the cases of heat transfer to air slot jets impinging on flat and concave surfaces. It is shown that for many practical problems, the use of very small heat flux gages is often unnecessary.

Thermoelectric Products

NASA Technical Reports Server (NTRS)

1988-01-01

Instead of bulky coils and compressors used in conventional refrigeration systems, UST design engineers drew on thermo-electric technology. UST's precision temperature chambers (PTC's) feature small thermoelectric modules that measure not much more than 1 square inch and operate on unique phenomenon of heat exchange. When electric current flows through specialized metallic crystals, heat is produced; when current direction is reversed cooling is produced.

Additive Manufacturing for Cost Efficient Production of Compact Ceramic Heat Exchangers and Recuperators

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shulman, Holly; Ross, Nicole

2015-10-30

An additive manufacture technique known as laminated object manufacturing (LOM) was used to fabricate compact ceramic heat exchanger prototypes. LOM uses precision CO2 laser cutting of ceramic green tapes, which are then precision stacked to build a 3D object with fine internal features. Modeling was used to develop prototype designs and predict the thermal response, stress, and efficiency in the ceramic heat exchangers. Build testing and materials analyses were used to provide feedback for the design selection. During this development process, laminated object manufacturing protocols were established. This included laser optimization, strategies for fine feature integrity, lamination fluid control, greenmore » handling, and firing profile. Three full size prototypes were fabricated using two different designs. One prototype was selected for performance testing. During testing, cross talk leakage prevented the application of a high pressure differential, however, the prototype was successful at withstanding the high temperature operating conditions (1300 °F). In addition, analysis showed that the bulk of the part did not have cracks or leakage issues. This led to the development of a module method for next generation LOM heat exchangers. A scale-up cost analysis showed that given a purpose built LOM system, these ceramic heat exchangers would be affordable for the applications.« less

PRECISE MEASUREMENT OF THE REIONIZATION OPTICAL DEPTH FROM THE GLOBAL 21 cm SIGNAL ACCOUNTING FOR COSMIC HEATING

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fialkov, Anastasia; Loeb, Abraham, E-mail: anastasia.fialkov@cfa.harvard.edu, E-mail: aloeb@cfa.harvard.edu

2016-04-10

As a result of our limited data on reionization, the total optical depth for electron scattering, τ, limits precision measurements of cosmological parameters from the Cosmic Microwave Background (CMB). It was recently shown that the predicted 21 cm signal of neutral hydrogen contains enough information to reconstruct τ with sub-percent accuracy, assuming that the neutral gas was much hotter than the CMB throughout the entire epoch of reionization (EoR). Here we relax this assumption and use the global 21 cm signal alone to extract τ for realistic X-ray heating scenarios. We test our model-independent approach using mock data for amore » wide range of ionization and heating histories and show that an accurate measurement of the reionization optical depth at a sub-percent level is possible in most of the considered scenarios even when heating is not saturated during the EoR, assuming that the foregrounds are mitigated. However, we find that in cases where heating sources had hard X-ray spectra and their luminosity was close to or lower than what is predicted based on low-redshift observations, the global 21 cm signal alone is not a good tracer of the reionization history.« less

The role of local heating in the 2015 Indian Heat Wave.

PubMed

Ghatak, Debjani; Zaitchik, Benjamin; Hain, Christopher; Anderson, Martha

2017-08-09

India faced a major heat wave during the summer of 2015. Temperature anomalies peaked in the dry period before the onset of the summer monsoon, suggesting that local land-atmosphere feedbacks involving desiccated soils and vegetation might have played a role in driving the heat extreme. Upon examination of in situ data, reanalysis, satellite observations, and land surface models, we find that the heat wave included two distinct peaks: one in late May, and a second in early June. During the first peak we find that clear skies led to a positive net radiation anomaly at the surface, but there is no significant sensible heat flux anomaly within the core of the heat wave affected region. By the time of the second peak, however, soil moisture had dropped to anomalously low levels in the core heat wave region, net surface radiation was anomalously high, and a significant positive sensible heat flux anomaly developed. This led to a substantial local forcing on air temperature that contributed to the intensity of the event. The analysis indicates that the highly agricultural landscape of North and Central India can reinforce heat extremes under dry conditions.

Neuronal nitric oxide synthase control mechanisms in the cutaneous vasculature of humans in vivo

PubMed Central

Kellogg, Dean L; Zhao, Joan L; Wu, Yubo

2008-01-01

The physiological roles of constituitively expressed nitric oxide synthase (NOS) isoforms in humans, in vivo, are unknown. Cutaneous vasodilatation during both central nervous system-mediated, thermoregulatory reflex responses to whole-body heat stress and during peripheral axon reflex-mediated, local responses to skin warming in humans depend on nitric oxide (NO) generation by constituitively expressed NOS of uncertain isoform. We hypothesized that neuronal NOS (nNOS, NOS I) effects cutaneous vasodilatation during whole-body heat stress, but not during local skin warming. We examined the effects of the nNOS inhibitor 7-nitroindazole (7-NI) administered by intradermal microdialysis on vasodilatation induced by whole-body heat stress or local skin warming. Skin blood flow (SkBF) was monitored by laser–Doppler flowmetry (LDF). Blood pressure (MAP) was monitored and cutaneous vascular conductance calculated (CVC = LDF/MAP). In protocol 1, whole-body heat stress was induced with water-perfused suits. In protocol 2, local skin warming was induced through local warming units at LDF sites. At the end of each protocol, 56 mm sodium nitroprusside was perfused at microdialysis sites to raise SkBF to maximal levels for data normalization. 7-NI significantly attenuated CVC increases during whole-body heat stress (P < 0.05), but had no effect on CVC increases induced by local skin warming (P > 0.05). These diametrically opposite effects of 7-NI on two NO-dependent processes verify selective nNOS antagonism, thus proving that the nNOS isoform affects NO increases and hence vasodilatation during centrally mediated, reflex responses to whole-body heat stress, but not during locally mediated, axon reflex responses to local skin warming. We conclude that the constituitively expressed nNOS isoform has distinct physiological roles in cardiovascular control mechanisms in humans, in vivo. PMID:18048451

Joining of thin glass with semiconductors by ultra-fast high-repetition laser welding

NASA Astrophysics Data System (ADS)

Horn, Alexander; Mingaeev, Ilja; Werth, Alexander; Kachel, Martin

2008-02-01

Lighting applications like OLED or on silicon for electro-optical applications need a reproducible sealing process. The joining has to be strong, the permeability for gasses and humidity very low and the process itself has to be very localized not affecting any organic or electronic parts inside the sealed region. The actual sealing process using glue does not fulfil these industrial needs. A new joining process using ultra-fast laser radiation offers a very precise joining with geometry dimensions smaller than 50 μm. Ultra-fast laser radiation is absorbed by multi-photon absorption in the glass. Due to the very definite threshold for melting and ablation the process of localized heating can be controlled without cracking. Repeating the irradiation at times smaller than the heat diffusion time the temperature in the focus is increased by heat accumulation reaching melting of the glass. Mowing the substrate relatively to the laser beam generates a seal of re-solidified glass. Joining of glass is achieved by positioning the laser focus at the interface. A similar approach is used for glass-silicon joining. The investigations presented will demonstrate the joining geometry by microscopy of cross-sections achieved by welding two glass plates (Schott D263 and AF45) with focused IR femtosecond laser radiation (wavelength λ = 1045nm, repetition rate f = 1 MHz, pulse duration t p = 500 fs, focus diameter w 0 = 4 μm, feeding velocity v= 1-10 mm/s). The strength of the welding seam is measured by tensile stress measurements and the gas and humidity is detected. A new diagnostic method for the on-line detection of the welding seam properties will be presented. Using a non-interferometric technique by quantitative phase microscopy the refractive index is measured during welding of glass in the time regime 0-2 μs. By calibration of the measured refractive index with a relation between refractive index and temperature a online-temperature detection can be achieved.

Precision enhancement of pavement roughness localization with connected vehicles

NASA Astrophysics Data System (ADS)

Bridgelall, R.; Huang, Y.; Zhang, Z.; Deng, F.

2016-02-01

Transportation agencies rely on the accurate localization and reporting of roadway anomalies that could pose serious hazards to the traveling public. However, the cost and technical limitations of present methods prevent their scaling to all roadways. Connected vehicles with on-board accelerometers and conventional geospatial position receivers offer an attractive alternative because of their potential to monitor all roadways in real-time. The conventional global positioning system is ubiquitous and essentially free to use but it produces impractically large position errors. This study evaluated the improvement in precision achievable by augmenting the conventional geo-fence system with a standard speed bump or an existing anomaly at a pre-determined position to establish a reference inertial marker. The speed sensor subsequently generates position tags for the remaining inertial samples by computing their path distances relative to the reference position. The error model and a case study using smartphones to emulate connected vehicles revealed that the precision in localization improves from tens of metres to sub-centimetre levels, and the accuracy of measuring localized roughness more than doubles. The research results demonstrate that transportation agencies will benefit from using the connected vehicle method to achieve precision and accuracy levels that are comparable to existing laser-based inertial profilers.

First Local Ties from Data of the Wettzell Triple Radio Telescope Array

NASA Astrophysics Data System (ADS)

Schüler, T.; Plötz, C.; Mähler, S.; Klügel, T.; Neidhardt, A.; Bertarini, A.; Halsig, S.; Nothnagel, A.; Lösler, M.; Eschelbach, C.; Anderson, J.

2016-12-01

The Geodetic Observatory Wettzell features three radio telescopes. Local ties between the reference points are available from terrestrial precision surveying with an expected accuracy below 0.7 mm. In addition, local VLBI data analysis is currently investigated to provide independent vectors and to provide quality feedback to the engineers. The preliminary results presented in this paper show a deviation from the local survey at the level of one millimeter with a clear systematic component. Sub-millimeter precision is reached after removal of this bias. This systematic effect is likely caused by omission of thermal expansion and gravity deformation, which is not yet implemented in our local VLBI analysis software.

A Robust Vehicle Localization Approach Based on GNSS/IMU/DMI/LiDAR Sensor Fusion for Autonomous Vehicles

PubMed Central

Meng, Xiaoli

2017-01-01

Precise and robust localization in a large-scale outdoor environment is essential for an autonomous vehicle. In order to improve the performance of the fusion of GNSS (Global Navigation Satellite System)/IMU (Inertial Measurement Unit)/DMI (Distance-Measuring Instruments), a multi-constraint fault detection approach is proposed to smooth the vehicle locations in spite of GNSS jumps. Furthermore, the lateral localization error is compensated by the point cloud-based lateral localization method proposed in this paper. Experiment results have verified the algorithms proposed in this paper, which shows that the algorithms proposed in this paper are capable of providing precise and robust vehicle localization. PMID:28926996

Video-rate nanoscopy enabled by sCMOS camera-specific single-molecule localization algorithms

PubMed Central

Huang, Fang; Hartwich, Tobias M. P.; Rivera-Molina, Felix E.; Lin, Yu; Duim, Whitney C.; Long, Jane J.; Uchil, Pradeep D.; Myers, Jordan R.; Baird, Michelle A.; Mothes, Walther; Davidson, Michael W.; Toomre, Derek; Bewersdorf, Joerg

2013-01-01

Newly developed scientific complementary metal–oxide–semiconductor (sCMOS) cameras have the potential to dramatically accelerate data acquisition in single-molecule switching nanoscopy (SMSN) while simultaneously increasing the effective quantum efficiency. However, sCMOS-intrinsic pixel-dependent readout noise substantially reduces the localization precision and introduces localization artifacts. Here we present algorithms that overcome these limitations and provide unbiased, precise localization of single molecules at the theoretical limit. In combination with a multi-emitter fitting algorithm, we demonstrate single-molecule localization super-resolution imaging at up to 32 reconstructed images/second (recorded at 1,600–3,200 camera frames/second) in both fixed and living cells. PMID:23708387

High-dimensional atom localization via spontaneously generated coherence in a microwave-driven atomic system.

PubMed

Wang, Zhiping; Chen, Jinyu; Yu, Benli

2017-02-20

We investigate the two-dimensional (2D) and three-dimensional (3D) atom localization behaviors via spontaneously generated coherence in a microwave-driven four-level atomic system. Owing to the space-dependent atom-field interaction, it is found that the detecting probability and precision of 2D and 3D atom localization behaviors can be significantly improved via adjusting the system parameters, the phase, amplitude, and initial population distribution. Interestingly, the atom can be localized in volumes that are substantially smaller than a cubic optical wavelength. Our scheme opens a promising way to achieve high-precision and high-efficiency atom localization, which provides some potential applications in high-dimensional atom nanolithography.

A Robust Vehicle Localization Approach Based on GNSS/IMU/DMI/LiDAR Sensor Fusion for Autonomous Vehicles.

PubMed

Meng, Xiaoli; Wang, Heng; Liu, Bingbing

2017-09-18

Precise and robust localization in a large-scale outdoor environment is essential for an autonomous vehicle. In order to improve the performance of the fusion of GNSS (Global Navigation Satellite System)/IMU (Inertial Measurement Unit)/DMI (Distance-Measuring Instruments), a multi-constraint fault detection approach is proposed to smooth the vehicle locations in spite of GNSS jumps. Furthermore, the lateral localization error is compensated by the point cloud-based lateral localization method proposed in this paper. Experiment results have verified the algorithms proposed in this paper, which shows that the algorithms proposed in this paper are capable of providing precise and robust vehicle localization.

Reduction to Outside the Atmosphere and Statistical Tests Used in Geneva Photometry

NASA Technical Reports Server (NTRS)

Rufener, F.

1984-01-01

Conditions for creating a precise photometric system are investigated. The analytical and discriminatory potentials of a photometry obviously result from the localization of the passbands in the spectrum; they do, however, also depend critically on the precision attained. This precision is the result of two different types of precautions. Two procedures which contribute in an efficient manner to achieving greater precision are examined. These two methods are known as hardware related precision and software related precision.

Novel localized heating technique on centrifugal microfluidic disc with wireless temperature monitoring system.

PubMed

Joseph, Karunan; Ibrahim, Fatimah; Cho, Jongman

2015-01-01

Recent advances in the field of centrifugal microfluidic disc suggest the need for electrical interface in the disc to perform active biomedical assays. In this paper, we have demonstrated an active application powered by the energy harvested from the rotation of the centrifugal microfluidic disc. A novel integration of power harvester disc onto centrifugal microfluidic disc to perform localized heating technique is the main idea of our paper. The power harvester disc utilizing electromagnetic induction mechanism generates electrical energy from the rotation of the disc. This contributes to the heat generation by the embedded heater on the localized heating disc. The main characteristic observed in our experiment is the heating pattern in relative to the rotation of the disc. The heating pattern is monitored wirelessly with a digital temperature sensing system also embedded on the disc. Maximum temperature achieved is 82 °C at rotational speed of 2000 RPM. The technique proves to be effective for continuous heating without the need to stop the centrifugal motion of the disc.

Localized Hyperthermia for Enhanced Targeted Delivery of Polymer Therapeutics

NASA Astrophysics Data System (ADS)

Frazier, Nicholas

It is estimated that in 2016, more than 848,000 new cases of cancer will be diagnosed in men with more than a quarter being prostate cancer and more than 26,000 deaths attributed to this disease. Prostate cancer poses a limited risk when detected at an early stage and treatment of stages II-III has a 5-year survival rate of almost 100%. However, these early-stage cancers can eventually progress and develop into stage IV, dramatically dropping the 5-year survival rate to 28%. Thus, development of a new therapy is needed to fully eliminate these tumors. Combination of heat and chemotherapy improves therapeutic efficacy while allowing for reduced dosing of drugs and limiting side effects. Localized hyperthermia has been used to enhance the delivery of polymer therapeutics to prostate tumors through increased blood flow, vascular permeability, and incorporation of heat shock targeting. This strategy has been shown to increase the delivery and retention of polymer-drug conjugates leading to enhanced efficacy. Although much work has been done using this strategy, the effects of different thermal dosing on polymer accumulation are unknown. The first aim of this research is to examine how altering heating parameters influences polymer tumor accumulation. The hypothesis for this aim is that there is an optimal thermal treatment that leads to the maximal amount of polymer accumulation in the tumors. Additionally, the previously used heating method of plasmonic photothermal therapy (PPTT) can result in long-term accumulation of gold nanoparticles in healthy organs, potentially limiting clinical applicability. The second aim of this proposal will be focused on investigating the alternative method of high intensity focused ultrasound (HIFU) for selective heating of tumors and enhancing macromolecular delivery. HIFU has shown the capability for precise, noninvasive heating of specific regions within the prostate through magnetic resonance imaging (MRI) guidance. The hypothesis to be tested in this aim is that mild hyperthermia produced with HIFU will have the same effect as that produced by PPTT in improving the delivery of macromolecular systems to solid tumors. Finally, in the third aim, the enhanced delivery of targeted polymer therapeutics to prostate tumors in mice models will be investigated using mild hyperthermia produced with HIFU. In the long term, it is anticipated that HIFU can be used in conjunction with delivery of polymer-drug conjugates for enhanced efficacy and reduced toxicity of chemotherapy to produce a clinically relevant treatment of advanced prostate cancer.

Photo-induced-heat localization on nanostructured metallic glasses

NASA Astrophysics Data System (ADS)

Uzun, Ceren; Kahler, Niloofar; Grave de Peralta, Luis; Kumar, Golden; Bernussi, Ayrton A.

2017-09-01

Materials with large photo-thermal energy conversion efficiency are essential for renewable energy applications. Photo-excitation is an effective approach to generate controlled and localized heat at relatively low excitation optical powers. However, lateral heat diffusion to the surrounding illuminated areas accompanied by low photo-thermal energy conversion efficiency remains a challenge for metallic surfaces. Surface nanoengineering has proven to be a successful approach to further absorption and heat generation. Here, we show that pronounced spatial heat localization and high temperatures can be achieved with arrays of amorphous metallic glass nanorods under infrared optical illumination. Thermography measurements revealed marked temperature contrast between illuminated and non-illuminated areas even under low optical power excitation conditions. This attribute allowed for generating legible photo-induced thermal patterns on textured metallic glass surfaces.

Focal gene misexpression in zebrafish embryos induced by local heat shock using a modified soldering iron.

PubMed

Hardy, Melissa E; Ross, Louis V; Chien, Chi-Bin

2007-11-01

Misexpression of genes in a temporally and spatially controlled fashion is an important tool for assessing gene function during development. Because few tissue-specific promoters have been identified in zebrafish, inducible systems such as the Cre/LoxP and Tet repressor systems are of limited utility. Here we describe a new method of misexpression: local heat shock using a modified soldering iron. Zebrafish carrying transgenes under the control of a heat shock promoter (hsp70) are focally heated with the soldering iron to induce gene expression in a small area of the embryo. We have validated this method in three stable transgenic lines and at three developmental timepoints. Local heat shock is a fast, easy, and inexpensive method for gene misexpression. Copyright 2007 Wiley-Liss, Inc.

Optimal Audiovisual Integration in the Ventriloquism Effect But Pervasive Deficits in Unisensory Spatial Localization in Amblyopia.

PubMed

Richards, Michael D; Goltz, Herbert C; Wong, Agnes M F

2018-01-01

Classically understood as a deficit in spatial vision, amblyopia is increasingly recognized to also impair audiovisual multisensory processing. Studies to date, however, have not determined whether the audiovisual abnormalities reflect a failure of multisensory integration, or an optimal strategy in the face of unisensory impairment. We use the ventriloquism effect and the maximum-likelihood estimation (MLE) model of optimal integration to investigate integration of audiovisual spatial information in amblyopia. Participants with unilateral amblyopia (n = 14; mean age 28.8 years; 7 anisometropic, 3 strabismic, 4 mixed mechanism) and visually normal controls (n = 16, mean age 29.2 years) localized brief unimodal auditory, unimodal visual, and bimodal (audiovisual) stimuli during binocular viewing using a location discrimination task. A subset of bimodal trials involved the ventriloquism effect, an illusion in which auditory and visual stimuli originating from different locations are perceived as originating from a single location. Localization precision and bias were determined by psychometric curve fitting, and the observed parameters were compared with predictions from the MLE model. Spatial localization precision was significantly reduced in the amblyopia group compared with the control group for unimodal visual, unimodal auditory, and bimodal stimuli. Analyses of localization precision and bias for bimodal stimuli showed no significant deviations from the MLE model in either the amblyopia group or the control group. Despite pervasive deficits in localization precision for visual, auditory, and audiovisual stimuli, audiovisual integration remains intact and optimal in unilateral amblyopia.

Tube furnace

DOEpatents

Foster, Kenneth G.; Frohwein, Eugene J.; Taylor, Robert W.; Bowen, David W.

1991-01-01

A vermiculite insulated tube furnace is heated by a helically-wound resistance wire positioned within a helical groove on the surface of a ceramic cylinder, that in turn is surroundingly disposed about a doubly slotted stainless steel cylindrical liner. For uniform heating, the pitch of the helix is of shorter length over the two end portions of the ceramic cylinder. The furnace is of large volume, provides uniform temperature, offers an extremely precise programmed heating capability, features very rapid cool-down, and has a modest electrical power requirement.

Silicon Field Effect Transistors as Dual-Use Sensor-Heater Hybrids

PubMed Central

Reddy, Bobby; Elibol, Oguz H.; Nair, Pradeep R.; Dorvel, Brian R.; Butler, Felice; Ahsan, Zahab; Bergstrom, Donald E.; Alam, Muhammad A.; Bashir, Rashid

2011-01-01

We demonstrate the temperature mediated applications of a previously proposed novel localized dielectric heating method on the surface of dual purpose silicon field effect transistor (FET) sensor-heaters and perform modeling and characterization of the underlying mechanisms. The FETs are first shown to operate as electrical sensors via sensitivity to changes in pH in ionic fluids. The same devices are then demonstrated as highly localized heaters via investigation of experimental heating profiles and comparison to simulation results. These results offer further insight into the heating mechanism and help determine the spatial resolution of the technique. Two important biosensor platform applications spanning different temperature ranges are then demonstrated: a localized heat-mediated DNA exchange reaction and a method for dense selective functionalization of probe molecules via the heat catalyzed complete desorption and reattachment of chemical functionalization to the transistor surfaces. Our results show that the use of silicon transistors can be extended beyond electrical switching and field-effect sensing to performing localized temperature controlled chemical reactions on the transistor itself. PMID:21214189

Heat Transfer and Fluid Transport of Supercritical CO 2 in Enhanced Geothermal System with Local Thermal Non-equilibrium Model

DOE PAGES

Zhang, Le; Luo, Feng; Xu, Ruina; ...

2014-12-31

The heat transfer and fluid transport of supercritical CO 2 in enhanced geothermal system (EGS) is studied numerically with local thermal non-equilibrium model, which accounts for the temperature difference between solid matrix and fluid components in porous media and uses two energy equations to describe heat transfer in the solid matrix and in the fluid, respectively. As compared with the previous results of our research group, the effect of local thermal non-equilibrium mainly depends on the volumetric heat transfer coefficient ah, which has a significant effect on the production temperature at reservoir outlet and thermal breakthrough time. The uniformity ofmore » volumetric heat transfer coefficient ah has little influence on the thermal breakthrough time, but the temperature difference become more obvious with time after thermal breakthrough with this simulation model. The thermal breakthrough time reduces and the effect of local thermal non-equilibrium becomes significant with decreasing ah.« less

Experiment of flow regime map and local condensing heat transfer coefficients inside three dimensional inner microfin tubes

NASA Astrophysics Data System (ADS)

Du, Yang; Xin, Ming Dao

1999-03-01

This paper developed a new type of three dimensional inner microfin tube. The experimental results of the flow patterns for the horizontal condensation inside these tubes are reported in the paper. The flow patterns for the horizontal condensation inside the new made tubes are divided into annular flow, stratified flow and intermittent flow within the test conditions. The experiments of the local heat transfer coefficients for the different flow patterns have been systematically carried out. The experiments of the local heat transfer coefficients changing with the vapor dryness fraction have also been carried out. As compared with the heat transfer coefficients of the two dimensional inner microfin tubes, those of the three dimensional inner microfin tubes increase 47-127% for the annular flow region, 38-183% for the stratified flow and 15-75% for the intermittent flow, respectively. The enhancement factor of the local heat transfer coefficients is from 1.8-6.9 for the vapor dryness fraction from 0.05 to 1.

Towards improved magnetic fluid hyperthermia: major-loops to diminish variations in local heating.

PubMed

Munoz-Menendez, Cristina; Serantes, David; Ruso, Juan M; Baldomir, Daniel

2017-06-07

In the context of using magnetic nanoparticles for heat-mediated applications, the need of an accurate knowledge of the local (at the nanoparticle level) heat generation in addition to the usually studied global counterpart has been recently highlighted. Such a need requires accurate knowledge of the links among the intrinsic particle properties, system characteristics and experimental conditions. In this work we have investigated the role of the particles' anisotropy polydispersity in relation to the amplitude (H max ) of the AC magnetic field using a Monte Carlo technique. Our results indicate that it is better to use particles with large anisotropy for enhancing global heating, whereas for achieving homogeneous local heating it is better to use lower anisotropy particles. The latter ensures that most of the system undergoes major-loop hysteresis conditions, which is the key-point. This is equivalent to say that low-anisotropy particles (i.e. with less heating capability) may be better for accurate heat-mediated applications, which goes against some research trends in the literature that seek for large anisotropy (and hence heating) values.

Generalization of the slip line field theory for temperature sensitive visco-plastic materials

NASA Astrophysics Data System (ADS)

Paesold, Martin; Peters, Max; Regenauer-Lieb, Klaus; Veveakis, Manolis; Bassom, Andrew

2015-04-01

Geological processes can be a combination of various effects such as heat production or consumption, chemical reactions or fluid flow. These individual effects are coupled to each other via feedbacks and the mathematical analysis becomes challenging due to these interdependencies. Here, we concentrate solely on thermo-mechanical coupling and a main result of this work is that the coupling can depend on material parameters and boundary conditions and the coupling is more or less pronounced depending on theses parameters. The transitions from weak to strong coupling can be studied in the context of a bifurcation analysis. classically, Material instabilities in solids are approached as material bifurcations of a rate-independent, isothermal, elasto-plastic solid. However, previous research has shown that temperature and deformation rate are important factors and are fully coupled with the mechanical deformation. Early experiments in steel revealed a distinct pattern of localized heat dissipation and plastic deformation known as heat lines. Further, earth materials, soils, rocks and ceramics are known to be greatly influenced by temperature with strain localization being strongly affected by thermal loading. In this work, we provide a theoretical framework for the evolution of plastic deformation for such coupled systems, with a two-pronged approach to the prediction of localized failure. First, slip line field theory is employed to predict the geometry of the failure patterns and second, failure criteria are derived from an energy bifurcation analysis. The bifurcation analysis is concerned with the local energy balance of a material and compares the effects of heat diffusion terms and heat production terms where the heat production is due to mechanical processes. Commonly, the heat is produced locally along the slip lines and if the heat production outweighs diffusion the material is locally weakened which eventually leads to failure. The effect of diffusion and heat production is captured by a dimensionless quantity, the Gruntfest number, and only if the Gruntfest number is larger than a critical value localized failure occurs. This critical Gruntfest number depends on boundary conditions such as temperature or pressure and hence this critical value gives rise to localization criteria. We find that the results of this approach agree with earlier contributions to the theory of plasticity but gives the advantage of a unified framework which might prove useful in numerical schemes for visco-plasticity.

Local precision nets for monitoring movements of faults and large engineering structures

NASA Technical Reports Server (NTRS)

Henneberg, H. G.

1978-01-01

Along Bocono Fault were installed local high precision geodetic nets to observe the possible horizontal crustal deformations and movements. In the fault area there are few big structures which are also included in the mentioned investigation. In the near future, measurements shall be extended to other sites of Bocono Fault and also to the El Pilar Fault. In the same way and by similar methods high precision geodetic nets are applied in Venezuela to observe the behavior of big structures, as bridges and large dams and of earth surface deformations due to industrial activities.

Fabrication of high wettability gradient on copper substrate

NASA Astrophysics Data System (ADS)

Huang, Ding-Jun; Leu, Tzong-Shyng

2013-09-01

Copper is one of the most widely used materials in condensation heat transfer. Recently there has been great interest in improving the condensation heat transfer efficiency through copper surface modification. In this study, we describe the fabrication processes of how copper surfaces were modified to be superhydrophilic (CA ≤ 10°) and superhydrophobic (CA > 150°) by means of H2O2 immersion and fluorination with Teflon. The wettability gradient of copper surfaces with contact angles (CA) changing from superhydrophilic to superhydrophobic are also demonstrated. Unlike previous studies on gradient surfaces in which the wettability gradient is controlled either non-precisely or entirely uncontrolled, in this study, the contact angles along wettability gradient copper surfaces vary with a precisely designed gradient. It is demonstrated that a high wettability gradient copper surface can be successfully fabricated using photolithography to define the area ratios between superhydrophilic and superhydrophobic patterns within a short distance. The fabricated wettability gradient of copper surfaces is expected to be able to enhance the condensation heat transfer efficiency.

Developing instrumentation to characterize thermoelectric generator modules.

PubMed

Liu, Dawei; Li, Qiming; Peng, Wenbo; Zhu, Lianjun; Gao, Hu; Meng, Qingsen; Jin, A J

2015-03-01

Based on the law of physics, known as "Seebeck effect," a thermoelectric generator (TEG) produces electricity when the temperature differential is applied across the TEG. This article reports a precision method in characterizing TEG modules. A precision instrument is constructed to study thermoelectric conversion in terms of output power and efficiency of TEG modules. The maximum allowable TEG module size is 150 mm, and the preferred size is from 30 mm to 60 mm. During measurements, the highest hot side temperature is 500 °C and the cold side temperature can be adjusted from room temperature to 100 °C. A mechanical structure is developed to control the pressure and parallelism of the clamping force of the TEG on both its hot and cold sides. A heat flux measurement module is installed at its cold side, and the heat flux through TEGs can be measured in position. Finally, the energy conversion efficiency of TEGs is calculated from experimental data of both an output power and a heat flux.

Local thermal sensation modeling-a review on the necessity and availability of local clothing properties and local metabolic heat production.

PubMed

Veselá, S; Kingma, B R M; Frijns, A J H

2017-03-01

Local thermal sensation modeling gained importance due to developments in personalized and locally applied heating and cooling systems in office environments. The accuracy of these models depends on skin temperature prediction by thermophysiological models, which in turn rely on accurate environmental and personal input data. Environmental parameters are measured or prescribed, but personal factors such as clothing properties and metabolic rates have to be estimated. Data for estimating the overall values of clothing properties and metabolic rates are available in several papers and standards. However, local values are more difficult to retrieve. For local clothing, this study revealed that full and consistent data sets are not available in the published literature for typical office clothing sets. Furthermore, the values for local heat production were not verified for characteristic office activities, but were adapted empirically. Further analyses showed that variations in input parameters can lead to local skin temperature differences (∆T skin,loc  = 0.4-4.4°C). These differences can affect the local sensation output, where ∆T skin,loc  = 1°C is approximately one step on a 9-point thermal sensation scale. In conclusion, future research should include a systematic study of local clothing properties and the development of feasible methods for measuring and validating local heat production. © 2016 The Authors. Indoor Air published by John Wiley & Sons Ltd.

Loop Heat Pipe Operation Using Heat Source Temperature for Set Point Control

NASA Technical Reports Server (NTRS)

Ku, Jentung; Paiva, Kleber; Mantelli, Marcia

2011-01-01

Loop heat pipes (LHPs) have been used for thermal control of several NASA and commercial orbiting spacecraft. The LHP operating temperature is governed by the saturation temperature of its compensation chamber (CC). Most LHPs use the CC temperature for feedback control of its operating temperature. There exists a thermal resistance between the heat source to be cooled by the LHP and the LHP's CC. Even if the CC set point temperature is controlled precisely, the heat source temperature will still vary with its heat output. For most applications, controlling the heat source temperature is of most interest. A logical question to ask is: "Can the heat source temperature be used for feedback control of the LHP operation?" A test program has been implemented to answer the above question. Objective is to investigate the LHP performance using the CC temperature and the heat source temperature for feedback control

Fundamental mechanisms in premixed flame propagation via vortex-flame interactions: Numerical simulations

NASA Technical Reports Server (NTRS)

Mantel, Thierry

1994-01-01

The goal of the present study is to assess numerically the ability of single-step and two-step chemical models to describe the main features encountered during the interaction between a two-dimensional vortex pair and a premixed laminar flame. In the two-step mechanism, the reaction kinetics are represented by a first chain branching reaction A + X yields 2X and a second chain termination reaction X + X yields P. This paper presents the fundamental mechanisms occurring during vortex-flame interactions and the relative impact of the major parameters encountered in turbulent premixed flames and suspected of playing a role in quenching mechanism: (1) Influence of stretch is investigated by analyzing the contribution of curvature and tangential strain on the local structure of the flame. The effect of Lewis number on the flame response to a strained field is analyzed. (2) Radiative heat losses which are suspected to be partially or totally responsible for quenching are also investigated. (3) The effect of the diffusion of the radicals is studied using a two-step mechanism in which an intermediate species is present. The parameters of the two-step mechanism are entirely determined from physical arguments. (4) Precise quantitative comparisons between the DNS and the experimental results of Samaniego et al are performed. These comparisons concern the evolution of the minimum heat release rate found along the flame front during the interaction and the distribution of the heat release rate along the flame front.

Heat capacty, relative enthalpy, and calorimetric entropy of silicate minerals: an empirical method of prediction.

USGS Publications Warehouse

Robinson, G.R.; Haas, J.L.

1983-01-01

Through the evaluation of experimental calorimetric data and estimates of the molar isobaric heat capacities, relative enthalpies and entropies of constituent oxides, a procedure for predicting the thermodynamic properties of silicates is developed. Estimates of the accuracy and precision of the technique and examples of its application are also presented. -J.A.Z.

A hypersonic aeroheating calculation method based on inviscid outer edge of boundary layer parameters

NASA Astrophysics Data System (ADS)

Meng, ZhuXuan; Fan, Hu; Peng, Ke; Zhang, WeiHua; Yang, HuiXin

2016-12-01

This article presents a rapid and accurate aeroheating calculation method for hypersonic vehicles. The main innovation is combining accurate of numerical method with efficient of engineering method, which makes aeroheating simulation more precise and faster. Based on the Prandtl boundary layer theory, the entire flow field is divided into inviscid and viscid flow at the outer edge of the boundary layer. The parameters at the outer edge of the boundary layer are numerically calculated from assuming inviscid flow. The thermodynamic parameters of constant-volume specific heat, constant-pressure specific heat and the specific heat ratio are calculated, the streamlines on the vehicle surface are derived and the heat flux is then obtained. The results of the double cone show that at the 0° and 10° angle of attack, the method of aeroheating calculation based on inviscid outer edge of boundary layer parameters reproduces the experimental data better than the engineering method. Also the proposed simulation results of the flight vehicle reproduce the viscid numerical results well. Hence, this method provides a promising way to overcome the high cost of numerical calculation and improves the precision.

Dynamically Reconfigurable Metadevice Employing Nanostructured Phase-Change Materials

DOE PAGES

Zhu, Zhihua; Evans, Philip G.; Haglund, Richard F.; ...

2017-07-21

Mastering dynamic free-space spectral control and modulation in the near-infrared (NIR) and optical regimes remains a challenging task that is hindered by the available functional materials at high frequencies. In this work, we have realized an efficient metadevice capable of spectral control by minimizing the thermal mass of a vanadium dioxide phase-change material (PCM) and placing the PCM at the feed gap of a bow-tie field antenna. The device has an experimentally measured tuning range of up to 360 nm in the NIR and a modulation depth of 33% at the resonant wavelength. The metadevice is configured for integrated andmore » local heating, leading to faster switching and more precise spatial control compared with devices based on phase-change thin films. We envisage that the combined advantages of this device will open new opportunities for signal processing, memory, security, and holography at optical frequencies.« less

Dynamically Reconfigurable Metadevice Employing Nanostructured Phase-Change Materials.

PubMed

Zhu, Zhihua; Evans, Philip G; Haglund, Richard F; Valentine, Jason G

2017-08-09

Mastering dynamic free-space spectral control and modulation in the near-infrared (NIR) and optical regimes remains a challenging task that is hindered by the available functional materials at high frequencies. In this work, we have realized an efficient metadevice capable of spectral control by minimizing the thermal mass of a vanadium dioxide phase-change material (PCM) and placing the PCM at the feed gap of a bow-tie field antenna. The device has an experimentally measured tuning range of up to 360 nm in the NIR and a modulation depth of 33% at the resonant wavelength. The metadevice is configured for integrated and local heating, leading to faster switching and more precise spatial control compared with devices based on phase-change thin films. We envisage that the combined advantages of this device will open new opportunities for signal processing, memory, security, and holography at optical frequencies.

Observation of negative differential resistance in mesoscopic graphene oxide devices.

PubMed

Rathi, Servin; Lee, Inyeal; Kang, Moonshik; Lim, Dongsuk; Lee, Yoontae; Yamacli, Serhan; Joh, Han-Ik; Kim, Seongsu; Kim, Sang-Woo; Yun, Sun Jin; Choi, Sukwon; Kim, Gil-Ho

2018-05-08

The fractions of various functional groups in graphene oxide (GO) are directly related to its electrical and chemical properties and can be controlled by various reduction methods like thermal, chemical and optical. However, a method with sufficient controllability to regulate the reduction process has been missing. In this work, a hybrid method of thermal and joule heating processes is demonstrated where a progressive control of the ratio of various functional groups can be achieved in a localized area. With this precise control of carbon-oxygen ratio, negative differential resistance (NDR) is observed in the current-voltage characteristics of a two-terminal device in the ambient environment due to charge-activated electrochemical reactions at the GO surface. This experimental observation correlates with the optical and chemical characterizations. This NDR behavior offers new opportunities for the fabrication and application of such novel electronic devices in a wide range of devices applications including switches and oscillators.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhu, Zhihua; Evans, Philip G.; Haglund, Richard F.

Mastering dynamic free-space spectral control and modulation in the near-infrared (NIR) and optical regimes remains a challenging task that is hindered by the available functional materials at high frequencies. In this work, we have realized an efficient metadevice capable of spectral control by minimizing the thermal mass of a vanadium dioxide phase-change material (PCM) and placing the PCM at the feed gap of a bow-tie field antenna. The device has an experimentally measured tuning range of up to 360 nm in the NIR and a modulation depth of 33% at the resonant wavelength. The metadevice is configured for integrated andmore » local heating, leading to faster switching and more precise spatial control compared with devices based on phase-change thin films. We envisage that the combined advantages of this device will open new opportunities for signal processing, memory, security, and holography at optical frequencies.« less

Live-cell thermometry with nitrogen vacancy centers in nanodiamonds

NASA Astrophysics Data System (ADS)

Jayakumar, Harishankar; Fedder, Helmut; Chen, Andrew; Yang, Liudi; Li, Chenghai; Wrachtrup, Joerg; Wang, Sihong; Meriles, Carlos

The ability to measure temperature is typically affected by a tradeoff between sensitivity and spatial resolution. Good thermometers tend to be bulky systems and hence are ill-suited for thermal sensing with high spatial localization. Conversely, the signal resulting from nanoscale temperature probes is often impacted by noise to a level where the measurement precision becomes poor. Adding to the microscopist toolbox, the nitrogen vacancy (NV) center in diamond has recently emerged as a promising platform for high-sensitivity nanoscale thermometry. Of particular interest are applications in living cells because diamond nanocrystals are biocompatible and can be chemically functionalized to target specific organelles. Here we report progress on the ability to probe and compare temperature within and between living cells using nanodiamond-hosted NV thermometry. We focus our study on cancerous cells, where atypical metabolic pathways arguably lead to changes in the way a cell generates heat, and thus on its temperature profile.

Occupational heat stress assessment and protective strategies in the context of climate change

NASA Astrophysics Data System (ADS)

Gao, Chuansi; Kuklane, Kalev; Östergren, Per-Olof; Kjellstrom, Tord

2018-03-01

Global warming will unquestionably increase the impact of heat on individuals who work in already hot workplaces in hot climate areas. The increasing prevalence of this environmental health risk requires the improvement of assessment methods linked to meteorological data. Such new methods will help to reveal the size of the problem and design appropriate interventions at individual, workplace and societal level. The evaluation of occupational heat stress requires measurement of four thermal climate factors (air temperature, humidity, air velocity and heat radiation); available weather station data may serve this purpose. However, the use of meteorological data for occupational heat stress assessment is limited because weather stations do not traditionally and directly measure some important climate factors, e.g. solar radiation. In addition, local workplace environmental conditions such as local heat sources, metabolic heat production within the human body, and clothing properties, all affect the exchange of heat between the body and the environment. A robust occupational heat stress index should properly address all these factors. This article reviews and highlights a number of selected heat stress indices, indicating their advantages and disadvantages in relation to meteorological data, local workplace environments, body heat production and the use of protective clothing. These heat stress and heat strain indices include Wet Bulb Globe Temperature, Discomfort Index, Predicted Heat Strain index, and Universal Thermal Climate Index. In some cases, individuals may be monitored for heat strain through physiological measurements and medical supervision prior to and during exposure. Relevant protective and preventive strategies for alleviating heat strain are also reviewed and proposed.

Occupational heat stress assessment and protective strategies in the context of climate change.

PubMed

Gao, Chuansi; Kuklane, Kalev; Östergren, Per-Olof; Kjellstrom, Tord

2018-03-01

Global warming will unquestionably increase the impact of heat on individuals who work in already hot workplaces in hot climate areas. The increasing prevalence of this environmental health risk requires the improvement of assessment methods linked to meteorological data. Such new methods will help to reveal the size of the problem and design appropriate interventions at individual, workplace and societal level. The evaluation of occupational heat stress requires measurement of four thermal climate factors (air temperature, humidity, air velocity and heat radiation); available weather station data may serve this purpose. However, the use of meteorological data for occupational heat stress assessment is limited because weather stations do not traditionally and directly measure some important climate factors, e.g. solar radiation. In addition, local workplace environmental conditions such as local heat sources, metabolic heat production within the human body, and clothing properties, all affect the exchange of heat between the body and the environment. A robust occupational heat stress index should properly address all these factors. This article reviews and highlights a number of selected heat stress indices, indicating their advantages and disadvantages in relation to meteorological data, local workplace environments, body heat production and the use of protective clothing. These heat stress and heat strain indices include Wet Bulb Globe Temperature, Discomfort Index, Predicted Heat Strain index, and Universal Thermal Climate Index. In some cases, individuals may be monitored for heat strain through physiological measurements and medical supervision prior to and during exposure. Relevant protective and preventive strategies for alleviating heat strain are also reviewed and proposed.

Note: Simultaneous determination of local temperature and thickness of heated cantilevers using two-wavelength thermoreflectance.

PubMed

Park, Heeseung; Lee, Bong Jae; Lee, Jungchul

2014-03-01

In this work, we have demonstrated that two-wavelength thermoreflectance technique can be used to characterize the local thickness and temperature of heated cantilevers at steady-state operation. By taking the ratio of reflectances for two lasers with different wavelengths, the geometrical factor causing the mismatch between experimentally measured and theoretically calculated reflectances was eliminated. Based on the fitting analysis of the reflectance ratio of two wavelengths at various input powers to the heated cantilevers, the local temperature and thickness could be unambiguously determined.

Local heating of the universe by the Higgs field

NASA Astrophysics Data System (ADS)

Belotsky, K. M.; Grobov, A. V.; Rubin, S. G.

It is shown that the creation of primordial massive black holes is accompanied by a local heating of the matter. The developed mechanism is based on the interaction of the Higgs field and a scalar field responsible for black hole formation. We also consider dynamical behavior of parameters such as a scale and chemical composition of such heating regions.

Remotely actuated localized pressure and heat apparatus and method of use

NASA Technical Reports Server (NTRS)

Merret, John B. (Inventor); Taylor, DeVor R. (Inventor); Wheeler, Mark M. (Inventor); Gale, Dan R. (Inventor)

2004-01-01

Apparatus and method for the use of a remotely actuated localized pressure and heat apparatus for the consolidation and curing of fiber elements in, structures. The apparatus includes members for clamping the desired portion of the fiber elements to be joined, pressure members and/or heat members. The method is directed to the application and use of the apparatus.

Combined passive acoustic mapping and magnetic resonance thermometry for monitoring phase-shift nanoemulsion enhanced focused ultrasound therapy

NASA Astrophysics Data System (ADS)

Crake, Calum; Meral, F. Can; Burgess, Mark T.; Papademetriou, Iason T.; McDannold, Nathan J.; Porter, Tyrone M.

2017-08-01

Focused ultrasound (FUS) has the potential to enable precise, image-guided noninvasive surgery for the treatment of cancer in which tumors are identified and destroyed in a single integrated procedure. However, success of the method in highly vascular organs has been limited due to heat losses to perfusion, requiring development of techniques to locally enhance energy absorption and heating. In addition, FUS procedures are conventionally monitored using MRI, which provides excellent anatomical images and can map temperature, but is not capable of capturing the full gamut of available data such as the acoustic emissions generated during this inherently acoustically-driven procedure. Here, we employed phase-shift nanoemulsions (PSNE) embedded in tissue phantoms to promote cavitation and hence temperature rise induced by FUS. In addition, we incorporated passive acoustic mapping (PAM) alongside simultaneous MR thermometry in order to visualize both acoustic emissions and temperature rise, within the bore of a full scale clinical MRI scanner. Focal cavitation of PSNE could be resolved using PAM and resulted in accelerated heating and increased the maximum elevated temperature measured via MR thermometry compared to experiments without nanoemulsions. Over time, the simultaneously acquired acoustic and temperature maps show translation of the focus of activity towards the FUS transducer, and the magnitude of the increase in cavitation and focal shift both increased with nanoemulsion concentration. PAM results were well correlated with MRI thermometry and demonstrated greater sensitivity, with the ability to detect cavitation before enhanced heating was observed. The results suggest that PSNE could be beneficial for enhancement of thermal focused ultrasound therapies and that PAM could be a critical tool for monitoring this process.

Fundamental Studies of Phase Transformations and Mechanical Properties in the Heat Affected Zone of 10 wt% Nickel Steel

NASA Astrophysics Data System (ADS)

Barrick, Erin J.

United States naval applications require the use of steels with high strength and resistance to fracture at low temperatures to provide good ballistic properties. In recent years, 10 wt% Ni steel has been developed with strength and toughness values exceeding those of steels currently used, and is now being considered as a candidate material to replace existing high-strength, low alloy steels. This steel has excellent toughness from the mechanically induced transformation of interlath austenite films to martensite. These austenite films are formed via a carefully developed quenching, lamellarizing, and tempering heat treatment. However, before 10 wt% Ni steel can be implemented for full-scale applications, the effects of the rapid heating and cooling rates associated with welding thermal cycles on phase transformations and mechanical properties must be understood. In this research, a fundamental understanding of phase transformations and mechanical properties in the heat-affected zone of fusion welds in 10 wt% Ni steel was developed through heating and cooling rate dilatometry experiments, gas tungsten arc welding, and simulation of gas metal arc welding. First, an investigation into the effects of heating and cooling rate on the phase transformations in 10 wt% Ni steel was performed. The Ac1 and Ac3 temperatures during heating were determined as a function of heating rate, and sluggish transformation during fast heating rates manifested itself as a high Ac3 temperature of 1050°C as opposed to a temperature of 850°C at slow heating rates. A continuous cooling transformation diagram produced for 10 wt% Ni steel reveals that martensite will form over a very wide range of cooling rates, which reflects a very high hardenability of this alloy. This is significant because the range of cooling rates for which the diagram was constructed over easily covers the range associated with fusion welding, so there would not be the need for precise control over the weld processing conditions. The microstructures observed in a single pass gas tungsten arc weld were rationalized with the observations from the heating and cooling rate experiments. The microhardness of gas tungsten arc weld is highest in the intercritical heat affected zone, which is unexpected based on the usual behavior of quench and tempered steels. The hardness of the heat affected zone is always higher than the base metal which is a promising outcome. Having understood the overall effects of heating and cooling on the phase transformations in 10 wt% Ni steel, the microstructure and mechanical property evolution through the heat affected zone was investigated. A Gleeble 3500 thermo-mechanical simulator was used to replicate microstructures observed in the gas-tungsten arc weld, and the microstructural factors influencing the strength and toughness in the simulated heat affected zone samples were correlated to mechanical property results. The strength is the highest in the intercritical heat-affected zone, mostly attributed to microstructural refinement. With increasing peak temperature of the thermal cycle, the volume fraction of retained austenite decreases. The local atom probe tomography results suggest this is due to the destabilization of the austenite brought on by the diffusion of Ni out of the austenite. There is a local low toughness region in the intercritical heat-affected zone, corresponding to a low retained austenite content. However, the retained austenite is similarly low in higher peak temperature regions but the toughness is high. This suggests that while 10 wt% Ni steel is a TRIP-assisted steel and thus obtains high toughness from the plasticity-induced martensite to austenite transformation, the toughness of the steel is also based on other microstructural factors. Overall, the results presented in this work have established, for the first time, the effects of rapid heating and cooling on the phase transformations and mechanical properties in 10 wt% Ni steel, and have started to identify the microstructural features influencing the strength and toughness of this alloy.

Acoustic Levitator With Furnace And Laser Heating

NASA Technical Reports Server (NTRS)

Barmatz, Martin B.; Stoneburner, James D.

1991-01-01

Acoustic-levitation apparatus incorporates electrical-resistance furnace for uniform heating up to temperature of about 1,000 degrees C. Additional local heating by pair of laser beams raise temperature of sample to more than 1,500 degrees C. High temperature single-mode acoustic levitator generates cylindrical-mode accoustic resonance levitating sample. Levitation chamber enclosed in electrical-resistance furnace. Infrared beams from Nd:YAG laser provide additional local heating of sample. Designed for use in containerless processing of materials in microgravity or in normal Earth gravity.

Machine-learning techniques for fast and accurate feature localization in holograms of colloidal particles

NASA Astrophysics Data System (ADS)

Hannel, Mark D.; Abdulali, Aidan; O'Brien, Michael; Grier, David G.

2018-06-01

Holograms of colloidal particles can be analyzed with the Lorenz-Mie theory of light scattering to measure individual particles' three-dimensional positions with nanometer precision while simultaneously estimating their sizes and refractive indexes. Extracting this wealth of information begins by detecting and localizing features of interest within individual holograms. Conventionally approached with heuristic algorithms, this image analysis problem can be solved faster and more generally with machine-learning techniques. We demonstrate that two popular machine-learning algorithms, cascade classifiers and deep convolutional neural networks (CNN), can solve the feature-localization problem orders of magnitude faster than current state-of-the-art techniques. Our CNN implementation localizes holographic features precisely enough to bootstrap more detailed analyses based on the Lorenz-Mie theory of light scattering. The wavelet-based Haar cascade proves to be less precise, but is so computationally efficient that it creates new opportunities for applications that emphasize speed and low cost. We demonstrate its use as a real-time targeting system for holographic optical trapping.

Nanoscopic imaging of thick heterogeneous soft-matter structures in aqueous solution

PubMed Central

Bartsch, Tobias F.; Kochanczyk, Martin D.; Lissek, Emanuel N.; Lange, Janina R.; Florin, Ernst-Ludwig

2016-01-01

Precise nanometre-scale imaging of soft structures at room temperature poses a major challenge to any type of microscopy because fast thermal fluctuations lead to significant motion blur if the position of the structure is measured with insufficient bandwidth. Moreover, precise localization is also affected by optical heterogeneities, which lead to deformations in the imaged local geometry, the severity depending on the sample and its thickness. Here we introduce quantitative thermal noise imaging, a three-dimensional scanning probe technique, as a method for imaging soft, optically heterogeneous and porous matter with submicroscopic spatial resolution in aqueous solution. By imaging both individual microtubules and collagen fibrils in a network, we demonstrate that structures can be localized with a precision of ∼10 nm and that their local dynamics can be quantified with 50 kHz bandwidth and subnanometre amplitudes. Furthermore, we show how image distortions caused by optically dense structures can be corrected for. PMID:27596919

Socio-economic factors affecting the conservation of natural woodlands in Central Riyadh Area – Saudi Arabia

PubMed Central

Al-Subaiee, Faisal Sultan

2015-01-01

This study aimed to identify some socioeconomic factors affecting local people in central Riyadh area for the utilization of wood and other energy sources in cooking and heating in order to develop some recommendations for conserving woodlands. The study results revealed that gas is the most common energy source used for cooking with a mean usage level of 2.79 (SD = 0.58). On the other hand, wood ranked first for heating with the highest mean, usage level of 1.90 (SD = 1.06). However, electricity and gas as sources of energy for heating ranked second and third with mean usage level of 1.81 and 0.80 respectively. The study revealed that local people with the university education were significantly making higher use of electricity for both cooking and heating and those with no formal education ranked the highest on wood use for both cooking and heating. In addition, those living in traditional houses significantly used more wood for cooking than those living in villas and apartments. Also, local people with high income levels significantly were using more electricity for heating than others. The study recommended conducting extension and environmental awareness raising programs to enhance local residents’ adoption of wood substitutes, promoting employment opportunities for unemployed locals, and subsidizing prices of alternative energy sources. PMID:27081355

Self-generated Local Heating Induced Nanojoining for Room Temperature Pressureless Flexible Electronic Packaging

PubMed Central

Peng, Peng; Hu, Anming; Gerlich, Adrian P.; Liu, Yangai; Zhou, Y. Norman

2015-01-01

Metallic bonding at an interface is determined by the application of heat and/or pressure. The means by which these are applied are the most critical for joining nanoscale structures. The present study considers the feasibility of room-temperature pressureless joining of copper wires using water-based silver nanowire paste. A novel mechanism of self-generated local heating within the silver nanowire paste and copper substrate system promotes the joining of silver-to-silver and silver-to-copper without any external energy input. The localized heat energy was delivered in-situ to the interfaces to promote atomic diffusion and metallic bond formation with the bulk component temperature stays near room-temperature. This local heating effect has been detected experimentally and confirmed by calculation. The joints formed at room-temperature without pressure achieve a tensile strength of 5.7 MPa and exhibit ultra-low resistivity in the range of 101.3 nOhm·m. The good conductivity of the joint is attributed to the removal of organic compounds in the paste and metallic bonding of silver-to-copper and silver-to-silver. The water-based silver nanowire paste filler material is successfully applied to various flexible substrates for room temperature bonding. The use of chemically generated local heating may become a potential method for energy in-situ delivery at micro/nanoscale. PMID:25788019

Resist heating effect on e-beam mask writing at 75 kV and 60 A/cm2

NASA Astrophysics Data System (ADS)

Benes, Zdenek; Deverich, Christina; Huang, Chester; Lawliss, Mark

2003-12-01

Resist heating has been known to be one of the main contributors to local CD variation in mask patterning using variable shape e-beam tools. Increasingly complex mask patterns require increased number of shapes which drives the need for higher electron beam current densities to maintain reasonable write times. As beam current density is increased, CD error resulting from resist heating may become a dominating contributor to local CD variations. In this experimental study, the IBM EL4+ mask writer with high voltage and high current density has been used to quantitatively investigate the effect of resist heating on the local CD uniformity. ZEP 7000 and several chemically amplified resists have been evaluated under various exposure conditions (single-pass, multi-pass, variable spot size) and pattern densities. Patterns were designed specifically to allow easy measurement of local CD variations with write strategies designed to maximize the effect of resist heating. Local CD variations as high as 15 nm in 18.75 × 18.75 μm sub-field size have been observed for ZEP 7000 in a single-pass writing with full 1000 nm spots at 50% pattern density. This number can be reduced by increasing the number of passes or by decreasing the maximum spot size. The local CD variation has been reduced to as low as 2 nm for ZEP 7000 for the same pattern under modified exposure conditions. The effectiveness of various writing strategies is discussed as well as their possible deficiencies. Minimal or no resist heating effects have been observed for the chemically amplified resists studied. The results suggest that the resist heating effect can be well controlled by careful selection of the resist/process system and/or writing strategy and that resist heating does not have to pose a problem for high throughput e-beam mask making that requires high voltage and high current densities.

A Non Local Electron Heat Transport Model for Multi-Dimensional Fluid Codes

NASA Astrophysics Data System (ADS)

Schurtz, Guy

2000-10-01

Apparent inhibition of thermal heat flow is one of the most ancient problems in computational Inertial Fusion and flux-limited Spitzer-Harm conduction has been a mainstay in multi-dimensional hydrodynamic codes for more than 25 years. Theoretical investigation of the problem indicates that heat transport in laser produced plasmas has to be considered as a non local process. Various authors contributed to the non local theory and proposed convolution formulas designed for practical implementation in one-dimensional fluid codes. Though the theory, confirmed by kinetic calculations, actually predicts a reduced heat flux, it fails to explain the very small limiters required in two-dimensional simulations. Fokker-Planck simulations by Epperlein, Rickard and Bell [PRL 61, 2453 (1988)] demonstrated that non local effects could lead to a strong reduction of heat flow in two dimensions, even in situations where a one-dimensional analysis suggests that the heat flow is nearly classical. We developed at CEA/DAM a non local electron heat transport model suitable for implementation in our two-dimensional radiation hydrodynamic code FCI2. This model may be envisionned as the first step of an iterative solution of the Fokker-Planck equations; it takes the mathematical form of multigroup diffusion equations, the solution of which yields both the heat flux and the departure of the electron distribution function to the Maxwellian. Although direct implementation of the model is straightforward, formal solutions of it can be expressed in convolution form, exhibiting a three-dimensional tensor propagator. Reduction to one dimension retrieves the original formula of Luciani, Mora and Virmont [PRL 51, 1664 (1983)]. Intense magnetic fields may be generated by thermal effects in laser targets; these fields, as well as non local effects, will inhibit electron conduction. We present simulations where both effects are taken into account and shortly discuss the coupling strategy between them.

Whole-body heating decreases skin vascular response to low orthostatic stress in the lower extremities.

PubMed

Yamazaki, Fumio; Nakayama, Yoshiro; Sone, Ryoko

2006-04-01

To elucidate the influence of heat stress on cutaneous vascular response in the lower extremities during orthostatic stress, a head-up tilt (HUT) test at angles of 15 degrees, 30 degrees, 45 degrees, and 60 degrees for 4 min each was conducted under normothermic control conditions followed by whole-body heat stress produced by a hot water-perfused suit in healthy volunteers. Skin blood flows (SkBF) in the forearm, thigh, and calf were monitored using laser-Doppler flowmetry throughout the experiment. Furthermore, to elucidate the effects of increased core and local skin temperatures on the local vascular response in calf skin under increasing orthostatic stress, the thigh was occluded at 20, 30, 50, 70, and 80 mmHg with a cuff in both the normothermic condition and the whole-body or local heating condition. Significant decreases in forearm SkBF during HUT were observed at an angle of 60 degrees during normothermia and at 30 degrees or more during heating. SkBF in the thigh and calf was decreased significantly by HUT at 15 degrees and above during normothermia, and there was no significant reduction of SkBF in these sites during HUT at the lower angles (15 degrees -45 degrees ) during whole-body heating. Significant decreases of calf SkBF were observed at cuff pressures of 20 mmHg and above during normothermia and of 30 mmHg and above during whole-body and local heating, respectively. These results suggest that SkBF in the lower extremities shows a marked reduction compared with the upper extremities during low orthostatic stress in normothermia, and the enhanced skin vasoconstrictor response in the lower extremities is diminished by both whole-body and local heat stress.

ON INTERMITTENT TURBULENCE HEATING OF THE SOLAR WIND: DIFFERENCES BETWEEN TANGENTIAL AND ROTATIONAL DISCONTINUITIES

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang Xin; Tu Chuanyi; He Jiansen

The intermittent structures in solar wind turbulence, studied by using measurements from the WIND spacecraft, are identified as being mostly rotational discontinuities (RDs) and rarely tangential discontinuities (TDs) based on the technique described by Smith. Only TD-associated current sheets (TCSs) are found to be accompanied with strong local heating of the solar wind plasma. Statistical results show that the TCSs have a distinct tendency to be associated with local enhancements of the proton temperature, density, and plasma beta, and a local decrease of magnetic field magnitude. Conversely, for RDs, our statistical results do not reveal convincing heating effects. These resultsmore » confirm the notion that dissipation of solar wind turbulence can take place in intermittent or locally isolated small-scale regions which correspond to TCSs. The possibility of heating associated with RDs is discussed.« less

3D DNS of Turbulent Premixed Flame with over 50 Species and 300 Elementary Reactions

NASA Astrophysics Data System (ADS)

Shimura, Masayasu; Yenerdag, Basmil; Naka, Yoshitsugu; Nada, Yuzuru; Tanahashi, Mamoru

2014-11-01

Three-dimensional direct numerical simulation of methane-air premixed planar flame propagating in homogenous isotropic turbulence is conducted to investigate local flame structure in thin reaction zones. Detailed kinetic mechanism, GRI-Mech 3.0 which includes 53 species and 325 elementary reactions, is used to represent methane-air reaction, and temperature dependences of transport and thermal properties are considered. For a better understanding of the local flame structure in thin reaction zones regime, distributions of mass fractions of major species, heat release rate, temperature and turbulent structures are investigated. Characteristic flame structures, such as radical fingering and multi-layered-like flame structures, are observed. The most expected maximum heat release rate in flame elements is lower than that of laminar flame with same mixture. To clarify mechanism of the decrease in local heat release rate, effects of strain rates tangential to flame front on local heat release rate are investigated.

Forced convection and flow boiling with and without enhancement devices for top-side-heated horizontal channels

NASA Technical Reports Server (NTRS)

Boyd, Ronald D., Sr.; Turknett, Jerry C.

1989-01-01

The effect of enhancement devices on flow boiling heat transfer in coolant channels, which are heated either from the top side or uniformly was studied. Studies are completed of the variations in the local (axial and circumferential) and mean heat transfer coefficients in horizontal, top-heated coolant channels with smooth walls and internal heat transfer enhancement devices. The working fluid is freon-11. The objectives are to: (1) examine the variations in both the mean and local (axial and circumferential) heat transfer coefficients for a circular coolant channel with either smooth walls or with both a twisted tape and spiral finned walls; (2) examine the effect of channel diameter (and the length-to-diameter aspect ratio) variations for the smooth wall channel; and (3) develop and improved data reduction analysis. The case of the top-heated, horizontal flow channel with smooth wall (1.37 cm inside diameter, and 122 cm heated length) was completed. The data were reduced using a preliminary analysis based on the heated hydraulic diameter. Preliminary examination of the local heat transfer coefficient variations indicated that there are significant axial and circumferential variations. However, it appears that the circumferential variation is more significant than the axial ones. In some cases, the circumferential variations were as much as a factor of ten. The axial variations rarely exceeded a factor of three.

A simple model of the effect of ocean ventilation on ocean heat uptake

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nadiga, Balasubramanya T.; Urban, Nathan Mark

Presentation includes slides on Earth System Models vs. Simple Climate Models; A Popular SCM: Energy Balance Model of Anomalies; On calibrating against one ESM experiment, the SCM correctly captures that ESM's surface warming response with other forcings; Multi-Model Analysis: Multiple ESMs, Single SCM; Posterior Distributions of ECS; However In Excess of 90% of TOA Energy Imbalance is Sequestered in the World Oceans; Heat Storage in the Two Layer Model; Heat Storage in the Two Layer Model; Including TOA Rad. Imbalance and Ocean Heat in Calibration Improves Repr., but Significant Errors Persist; Improved Vertical Resolution Does Not Fix Problem; A Seriesmore » of Expts. Confirms That Anomaly-Diffusing Models Cannot Properly Represent Ocean Heat Uptake; Physics of the Thermocline; Outcropping Isopycnals and Horizontally-Averaged Layers; Local interactions between outcropping isopycnals leads to non-local interactions between horizontally-averaged layers; Both Surface Warming and Ocean Heat are Well Represented With Just 4 Layers; A Series of Expts. Confirms That When Non-Local Interactions are Allowed, the SCMs Can Represent Both Surface Warming and Ocean Heat Uptake; and Summary and Conclusions.« less

Implementation of one and three dimensional models for heat transfer coeffcient identification over the plate cooled by the circular water jets

NASA Astrophysics Data System (ADS)

Malinowski, Zbigniew; Cebo-Rudnicka, Agnieszka; Hadała, Beata; Szajding, Artur; Telejko, Tadeusz

2017-10-01

A cooling rate affects the mechanical properties of steel which strongly depend on microstructure evolution processes. The heat transfer boundary condition for the numerical simulation of steel cooling by water jets can be determined from the local one dimensional or from the three dimensional inverse solutions in space and time. In the present study the inconel plate has been heated to about 900 °C and then cooled by six circular water jets. The plate temperature has been measured by 30 thermocouples. The heat transfer coefficient and the heat flux distributions at the plate surface have been determined in time and space. The one dimensional solutions have given a local error to the heat transfer coefficient of about 35%. The three dimensional inverse solution has allowed reducing the local error to about 20%. The uncertainty test has confirmed that a better approximation of the heat transfer coefficient distribution over the cooled surface can be obtained even for limited number of thermocouples. In such a case it was necessary to constrain the inverse solution with the interpolated temperature sensors.

Local heat-transfer measurements on a large, scale-model turbine blade airfoil using a composite of a heater element and liquid crystals

NASA Technical Reports Server (NTRS)

Hippensteele, S. A.; Russell, L. M.; Torres, F. J.

1985-01-01

Local heat transfer coefficients were experimentally mapped along the midchord of a five-time-size turbine blade airfoil in a static cascade operated at room temperature over a range of Reynolds numbers. The test surface consisted of a composite of commercially available materials: a mylar sheet with a layer of cholesteric liquid crystals, that change color with temperature, and a heater sheet made of a carbon-impregnated paper, that produces uniform heat flux. After the initial selection and calibration of the composite sheet, accurate, quantitative, and continuous heat transfer coefficients were mapped over the airfoil surface. The local heat transfer coefficients are presented for Reynolds numbers from 2.8 x 10 to the 5th power to 7.6 x 10 to the 5th power. Comparisons are made with analytical values of heat transfer coefficients obtained from the STAN5 boundary layer code. Also, a leading edge separation bubble was revealed by thermal and flow visualization.

Natural convection in symmetrically heated vertical parallel plates with discrete heat sources

DOE Office of Scientific and Technical Information (OSTI.GOV)

Manca, O.; Nardini, S.; Naso, V.

Laminar air natural convection in a symmetrically heated vertical channel with uniform flush-mounted discrete heat sources has been experimentally investigated. The effects of heated strips location and of their number are pointed out in terms of the maximum wall temperatures. A flow visualization in the entrance region of the channel was carried out and air temperatures and velocities in two cross sections have been measured. Dimensionless local heat transfer coefficients have been evaluated and monomial correlations among relevant parameters have bee derived in the local Rayleigh number range 10--10{sup 6}. Channel Nusselt number has been correlated in a polynomial formmore » in terms of channel Rayleigh number.« less

Characterization of microstructure, local deformation and microchemistry in Alloy 690 heat-affected zone and stress corrosion cracking in high temperature water

NASA Astrophysics Data System (ADS)

Lu, Zhanpeng; Chen, Junjie; Shoji, Tetsuo; Takeda, Yoichi; Yamazaki, Seiya

2015-10-01

With increasing the distance from the weld fusion line in an Alloy 690 heat-affected zone, micro-hardness decreases, kernel average misorientation decreases and the fraction of Σ3 boundaries increases. Chromium depletion at grain boundaries in the Alloy 690 heat-affected zone is less significant than that in an Alloy 600 heat-affected zone. Alloy 690 heat-affected zone exhibits much higher IGSCC resistance than Alloy 600 heat-affected zone in simulated pressurized water reactor primary water. Heavily cold worked Alloy 690 exhibits localized intergranular stress corrosion cracking. The effects of metallurgical and mechanical properties on stress corrosion cracking in Alloy 690 are discussed.

Profiling Systems Using the Defining Characteristics of Systems of Systems (SoS)

DTIC Science & Technology

2010-02-01

system exhaust and emissions system gas engine heating and air conditioning system fuel system regenerative braking system safety system...overcome the limitations of these fuzzy scales, measurement scales are often divided into a relatively small number of disjoint categories so that the...precision is not justified. This lack of precision can typically be addressed by breaking the measurement scale into a set of categories , the use of

High thermal conductivity liquid metal pad for heat dissipation in electronic devices

NASA Astrophysics Data System (ADS)

Lin, Zuoye; Liu, Huiqiang; Li, Qiuguo; Liu, Han; Chu, Sheng; Yang, Yuhua; Chu, Guang

2018-05-01

Novel thermal interface materials using Ag-doped Ga-based liquid metal were proposed for heat dissipation of electronic packaging and precision equipment. On one hand, the viscosity and fluidity of liquid metal was controlled to prevent leakage; on the other hand, the thermal conductivity of the Ga-based liquid metal was increased up to 46 W/mK by incorporating Ag nanoparticles. A series of experiments were performed to evaluate the heat dissipation performance on a CPU of smart-phone. The results demonstrated that the Ag-doped Ga-based liquid metal pad can effectively decrease the CPU temperature and change the heat flow path inside the smart-phone. To understand the heat flow path from CPU to screen through the interface material, heat dissipation mechanism was simulated and discussed.

Local heat stroke prevention plans in Japan: characteristics and elements for public health adaptation to climate change.

PubMed

Martinez, Gerardo Sanchez; Imai, Chisato; Masumo, Kanako

2011-12-01

The adverse health effects from hot weather and heat waves represent significant public health risks in vulnerable areas worldwide. Rising temperatures due to climate change are aggravating these risks in a context of fast urbanization, population growth and societal ageing. However, environmental heat-related health effects are largely preventable through adequate preparedness and responses. Public health adaptation to climate change will often require the implementation of heat wave warning systems and targeted preventive activities at different levels. While several national governments have established such systems at the country level, municipalities do not generally play a major role in the prevention of heat disorders. This paper analyzes selected examples of locally operated heat-health prevention plans in Japan. The analysis of these plans highlights their strengths, but also the need of local institutions for assistance to make the transition towards an effective public health management of high temperatures and heat waves. It can also provide useful elements for municipal governments in vulnerable areas, both in planning their climate change and health adaptation activities or to better protect their communities against current health effects from heat.

Infrared thermography with non-uniform heat flux boundary conditions on the rotor endwall of an axial turbine

NASA Astrophysics Data System (ADS)

Lazzi Gazzini, S.; Schädler, R.; Kalfas, A. I.; Abhari, R. S.

2017-02-01

It is technically challenging to measure heat fluxes on the rotating components of gas turbines, yet accurate knowledge of local heat loads under engine-representative conditions is crucial for ensuring the reliability of the designs. In this work, quantitative image processing tools were developed to perform fast and accurate infrared thermography measurements on 3D-shaped film-heaters directly deposited on the turbine endwalls. The newly developed image processing method and instrumentation were used to measure the heat load on the rotor endwalls of an axial turbine. A step-transient heat flux calibration technique is applied to measure the heat flux generated locally by the film heater, thus eliminating the need for a rigorously iso-energetic boundary condition. On-board electronics installed on the rotor record the temperature readings of RTDs installed in the substrate below the heaters in order to evaluate the conductive losses in the solid. Full maps of heat transfer coefficient and adiabatic wall temperature are produced for two different operating conditions, demonstrating the sensitivity of the technique to local flow features and variations in heat transfer due to Reynolds number effect.

Local Heat Stroke Prevention Plans in Japan: Characteristics and Elements for Public Health Adaptation to Climate Change

PubMed Central

Martinez, Gerardo Sanchez; Imai, Chisato; Masumo, Kanako

2011-01-01

The adverse health effects from hot weather and heat waves represent significant public health risks in vulnerable areas worldwide. Rising temperatures due to climate change are aggravating these risks in a context of fast urbanization, population growth and societal ageing. However, environmental heat-related health effects are largely preventable through adequate preparedness and responses. Public health adaptation to climate change will often require the implementation of heat wave warning systems and targeted preventive activities at different levels. While several national governments have established such systems at the country level, municipalities do not generally play a major role in the prevention of heat disorders. This paper analyzes selected examples of locally operated heat-health prevention plans in Japan. The analysis of these plans highlights their strengths, but also the need of local institutions for assistance to make the transition towards an effective public health management of high temperatures and heat waves. It can also provide useful elements for municipal governments in vulnerable areas, both in planning their climate change and health adaptation activities or to better protect their communities against current health effects from heat. PMID:22408589

Local endwall heat/mass-transfer distributions in pin fin channels

NASA Astrophysics Data System (ADS)

Lau, S. C.; Kim, Y. S.; Han, J. C.

1987-10-01

Naphthalene sublimination experiments were conducted to study the effects of the pin configuration, the pin length-to-diameter ratio, and the entrance length on local endwall heat/mass transfer in a channel with short pin fins (pin length-to-diameter ratios of 0.5 and 1.0). The detailed distributions of the local endwall heat/mass-transfer coefficient were obtained for staggered and aligned arrays of pin fins, for the spanwise pin spacing-to-diameter ratio of 2.5, and for streamwise pin spacing-to-diameter ratios of 1.25 and 2.5. The Reynolds numbers were kept at about 33,000. Overall- and row-averaged Nusselt numbers compared very well with those from previous heat-transfer studies.

Design of a self-calibration high precision micro-angle deformation optical monitoring scheme

NASA Astrophysics Data System (ADS)

Gu, Yingying; Wang, Li; Guo, Shaogang; Wu, Yun; Liu, Da

2018-03-01

In order to meet the requirement of high precision and micro-angle measurement on orbit, a self-calibrated optical non-contact real-time monitoring device is designed. Within three meters, the micro-angle variable of target relative to measuring basis can be measured in real-time. The range of angle measurement is +/-50'', the angle measurement accuracy is less than 2''. The equipment can realize high precision real-time monitoring the micro-angle deformation, which caused by high strength vibration and shock of rock launching, sun radiation and heat conduction on orbit and so on.

High level continuity for coordinate generation with precise controls

NASA Technical Reports Server (NTRS)

Eiseman, P. R.

1982-01-01

Coordinate generation techniques with precise local controls have been derived and analyzed for continuity requirements up to both the first and second derivatives, and have been projected to higher level continuity requirements from the established pattern. The desired local control precision was obtained when a family of coordinate surfaces could be uniformly distributed without a consequent creation of flat spots on the coordinate curves transverse to the family. Relative to the uniform distribution, the family could be redistributed from an a priori distribution function or from a solution adaptive approach, both without distortion from the underlying transformation which may be independently chosen to fit a nontrivial geometry and topology.

Miniature Microwave Applicator for Murine Bladder Hyperthermia Studies

PubMed Central

Salahi, Sara; Maccarini, Paolo F.; Rodrigues, Dario B.; Etienne, Wiguins; Landon, Chelsea D.; Inman, Brant A.; Dewhirst, Mark W.; Stauffer, Paul R.

2012-01-01

Purpose Novel combinations of heat with chemotherapeutic agents are often studied in murine tumor models. Currently, no device exists to selectively heat small tumors at depth in mice. In this project, we modelled, built and tested a miniature microwave heat applicator, the physical dimensions of which can be scaled to adjust the volume and depth of heating to focus on the tumor volume. Of particular interest is a device that can selectively heat murine bladder. Materials and Methods Using Avizo® segmentation software, we created a numerical mouse model based on micro-MRI scan data. The model was imported into HFSS™ simulation software and parametric studies were performed to optimize the dimensions of a water-loaded circular waveguide for selective power deposition inside a 0.15ml bladder. A working prototype was constructed operating at 2.45GHz. Heating performance was characterized by mapping fiber-optic temperature sensors along catheters inserted at depths of 0-1mm (subcutaneous), 2-3mm (vaginal), and 4-5mm (rectal) below the abdominal wall, with the mid-depth catheter adjacent to the bladder. Core temperature was monitored orally. Results Thermal measurements confirm the simulations which demonstrate that this applicator can provide local heating at depth in small animals. Measured temperatures in murine pelvis show well-localized bladder heating to 42-43°C while maintaining normothermic skin and core temperatures. Conclusions Simulation techniques facilitate the design optimization of microwave antennas for use in pre-clinical applications such as localized tumor heating in small animals. Laboratory measurements demonstrate the effectiveness of a new miniature water-coupled microwave applicator for localized heating of murine bladder. PMID:22690856

Automation of Precise Time Reference Stations (PTRS)

NASA Astrophysics Data System (ADS)

Wheeler, P. J.

1985-04-01

The U.S. Naval Observatory is presently engaged in a program of automating precise time stations (PTS) and precise time reference stations (PTBS) by using a versatile mini-computer controlled data acquisition system (DAS). The data acquisition system is configured to monitor locally available PTTI signals such as LORAN-C, OMEGA, and/or the Global Positioning System. In addition, the DAS performs local standard intercomparison. Computer telephone communications provide automatic data transfer to the Naval Observatory. Subsequently, after analysis of the data, results and information can be sent back to the precise time reference station to provide automatic control of remote station timing. The DAS configuration is designed around state of the art standard industrial high reliability modules. The system integration and software are standardized but allow considerable flexibility to satisfy special local requirements such as stability measurements, performance evaluation and printing of messages and certificates. The DAS operates completely independently and may be queried or controlled at any time with a computer or terminal device (control is protected for use by authorized personnel only). Such DAS equipped PTS are operational in Hawaii, California, Texas and Florida.

Anisotropic pyrochemical microetching of poly(tetrafluoroethylene) initiated by synchrotron radiation-induced scission of molecule bonds

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yamaguchi, Akinobu, E-mail: yamaguti@lasti.u-hyogo.ac.jp, E-mail: utsumi@lasti.u-hyogo.ac.jp; Kido, Hideki; Utsumi, Yuichi, E-mail: yamaguti@lasti.u-hyogo.ac.jp, E-mail: utsumi@lasti.u-hyogo.ac.jp

2016-02-01

We developed a process for micromachining polytetrafluoroethylene (PTFE): anisotropic pyrochemical microetching induced by synchrotron X-ray irradiation. X-ray irradiation was performed at room temperature. Upon heating, the irradiated PTFE substrates exhibited high-precision features. Both the X-ray diffraction peak and Raman signal from the irradiated areas of the substrate decreased with increasing irradiation dose. The etching mechanism is speculated as follows: X-ray irradiation caused chain scission, which decreased the number-average degree of polymerization. The melting temperature of irradiated PTFE decreased as the polymer chain length decreased, enabling the treated regions to melt at a lower temperature. The anisotropic pyrochemical etching process enabledmore » the fabrication of PTFE microstructures with higher precision than simultaneously heating and irradiating the sample.« less

Image analysis of speckle patterns as a probe of melting transitions in laser-heated diamond anvil cell experiments.

PubMed

Salem, Ran; Matityahu, Shlomi; Melchior, Aviva; Nikolaevsky, Mark; Noked, Ori; Sterer, Eran

2015-09-01

The precision of melting curve measurements using laser-heated diamond anvil cell (LHDAC) is largely limited by the correct and reliable determination of the onset of melting. We present a novel image analysis of speckle interference patterns in the LHDAC as a way to define quantitative measures which enable an objective determination of the melting transition. Combined with our low-temperature customized IR pyrometer, designed for measurements down to 500 K, our setup allows studying the melting curve of materials with low melting temperatures, with relatively high precision. As an application, the melting curve of Te was measured up to 35 GPa. The results are found to be in good agreement with previous data obtained at pressures up to 10 GPa.

Precise new shock temperatures in forsterite and in silicate liquids: phase transitions and heat capacity at high pressure

NASA Astrophysics Data System (ADS)

Asimow, P. D.; Fat'yanov, O. V.; Su, C.; Ma, X. J.

2017-12-01

Shock temperature measurements in transparent samples provide key constraints on the phase transitions and thermodynamic properties of materials at high pressure and temperature. Such measurements are necessary, for example, to allow equation of state measurements taken along the Hugoniot to be translated to P-V-T space. We have recently completed a detailed study of the accuracy and reproducibility of calibration of our 6-channel fast pyrometer. We have also introduced improved analysis procedures of the time-dependent multi-wavelength radiance signal that avoid the need for a greybody assumption and therefore have better precision than earlier results. This has motivated (a) renewed study of the shock temperature of forsterite in the superheating, partial melting, and complete melting regimes, (b) pre-heated diopside-anorthite glass shock temperature experiments for comparison to pre-heated silicate liquid equation of state results, and (c) new soda-lime glass shock temperature experiments. Single-crystal synthetic forsterite samples were shocked along (100) to pressures between 120 and 210 GPa on the Caltech two-stage light gas gun. Uncertainties on most results are 50 K. Results above the onset of partial melting at 130 GPa are consistent with Lyzenga and Ahrens (1980) data and show a low P-T slope consistent with a partial melting interval. Complete melting may occur, given sufficient time, at about 210 GPa. The experiment at 120-130 GPa is anomalous, showing two-wave structure and time- and wavelength-dependent scattering suggesting a subsolidus phase transition behind the shock front. The amount of super-heating, if any, is far smaller than claimed by Holland and Ahrens (1997). Steady radiation profiles, high emissivity, and consistency from channel to channel provide high precision (±40 K) in diopside-anorthite liquid shocked from just above the glass transition to high pressure. Temperatures are colder than expected for a model with constant heat capacity, providing direct evidence that multicomponent silicate liquids show a major increase in heat capacity in the P-T range appropriate to terrestrial magma oceans (<150 GPa, <5000 K).

Limits to the precision of gradient sensing with spatial communication and temporal integration.

PubMed

Mugler, Andrew; Levchenko, Andre; Nemenman, Ilya

2016-02-09

Gradient sensing requires at least two measurements at different points in space. These measurements must then be communicated to a common location to be compared, which is unavoidably noisy. Although much is known about the limits of measurement precision by cells, the limits placed by the communication are not understood. Motivated by recent experiments, we derive the fundamental limits to the precision of gradient sensing in a multicellular system, accounting for communication and temporal integration. The gradient is estimated by comparing a "local" and a "global" molecular reporter of the external concentration, where the global reporter is exchanged between neighboring cells. Using the fluctuation-dissipation framework, we find, in contrast to the case when communication is ignored, that precision saturates with the number of cells independently of the measurement time duration, because communication establishes a maximum length scale over which sensory information can be reliably conveyed. Surprisingly, we also find that precision is improved if the local reporter is exchanged between cells as well, albeit more slowly than the global reporter. The reason is that whereas exchange of the local reporter weakens the comparison, it decreases the measurement noise. We term such a model "regional excitation-global inhibition." Our results demonstrate that fundamental sensing limits are necessarily sharpened when the need to communicate information is taken into account.

Time Delay Embedding Increases Estimation Precision of Models of Intraindividual Variability

ERIC Educational Resources Information Center

von Oertzen, Timo; Boker, Steven M.

2010-01-01

This paper investigates the precision of parameters estimated from local samples of time dependent functions. We find that "time delay embedding," i.e., structuring data prior to analysis by constructing a data matrix of overlapping samples, increases the precision of parameter estimates and in turn statistical power compared to standard…

Novel Mitochondria-Targeted Heat-Soluble Proteins Identified in the Anhydrobiotic Tardigrade Improve Osmotic Tolerance of Human Cells

PubMed Central

Tanaka, Sae; Tanaka, Junko; Miwa, Yoshihiro; Horikawa, Daiki D.; Katayama, Toshiaki; Arakawa, Kazuharu; Toyoda, Atsushi; Kubo, Takeo; Kunieda, Takekazu

2015-01-01

Tardigrades are able to tolerate almost complete dehydration through transition to a metabolically inactive state, called “anhydrobiosis”. Late Embryogenesis Abundant (LEA) proteins are heat-soluble proteins involved in the desiccation tolerance of many anhydrobiotic organisms. Tardigrades, Ramazzottius varieornatus, however, express predominantly tardigrade-unique heat-soluble proteins: CAHS (Cytoplasmic Abundant Heat Soluble) and SAHS (Secretory Abundant Heat Soluble) proteins, which are secreted or localized in most intracellular compartments, except the mitochondria. Although mitochondrial integrity is crucial to ensure cellular survival, protective molecules for mitochondria have remained elusive. Here, we identified two novel mitochondrial heat-soluble proteins, RvLEAM and MAHS (Mitochondrial Abundant Heat Soluble), as potent mitochondrial protectants from Ramazzottius varieornatus. RvLEAM is a group3 LEA protein and immunohistochemistry confirmed its mitochondrial localization in tardigrade cells. MAHS-green fluorescent protein fusion protein localized in human mitochondria and was heat-soluble in vitro, though no sequence similarity with other known proteins was found, and one region was conserved among tardigrades. Furthermore, we demonstrated that RvLEAM protein as well as MAHS protein improved the hyperosmotic tolerance of human cells. The findings of the present study revealed that tardigrade mitochondria contain at least two types of heat-soluble proteins that might have protective roles in water-deficient environments. PMID:25675104

Novel mitochondria-targeted heat-soluble proteins identified in the anhydrobiotic Tardigrade improve osmotic tolerance of human cells.

PubMed

Tanaka, Sae; Tanaka, Junko; Miwa, Yoshihiro; Horikawa, Daiki D; Katayama, Toshiaki; Arakawa, Kazuharu; Toyoda, Atsushi; Kubo, Takeo; Kunieda, Takekazu

2015-01-01

Tardigrades are able to tolerate almost complete dehydration through transition to a metabolically inactive state, called "anhydrobiosis". Late Embryogenesis Abundant (LEA) proteins are heat-soluble proteins involved in the desiccation tolerance of many anhydrobiotic organisms. Tardigrades, Ramazzottius varieornatus, however, express predominantly tardigrade-unique heat-soluble proteins: CAHS (Cytoplasmic Abundant Heat Soluble) and SAHS (Secretory Abundant Heat Soluble) proteins, which are secreted or localized in most intracellular compartments, except the mitochondria. Although mitochondrial integrity is crucial to ensure cellular survival, protective molecules for mitochondria have remained elusive. Here, we identified two novel mitochondrial heat-soluble proteins, RvLEAM and MAHS (Mitochondrial Abundant Heat Soluble), as potent mitochondrial protectants from Ramazzottius varieornatus. RvLEAM is a group3 LEA protein and immunohistochemistry confirmed its mitochondrial localization in tardigrade cells. MAHS-green fluorescent protein fusion protein localized in human mitochondria and was heat-soluble in vitro, though no sequence similarity with other known proteins was found, and one region was conserved among tardigrades. Furthermore, we demonstrated that RvLEAM protein as well as MAHS protein improved the hyperosmotic tolerance of human cells. The findings of the present study revealed that tardigrade mitochondria contain at least two types of heat-soluble proteins that might have protective roles in water-deficient environments.

Tracking heat flux sensors for concentrating solar applications

DOEpatents

Andraka, Charles E; Diver, Jr., Richard B

2013-06-11

Innovative tracking heat flux sensors located at or near the solar collector's focus for centering the concentrated image on a receiver assembly. With flux sensors mounted near a receiver's aperture, the flux gradient near the focus of a dish or trough collector can be used to precisely position the focused solar flux on the receiver. The heat flux sensors comprise two closely-coupled thermocouple junctions with opposing electrical polarity that are separated by a thermal resistor. This arrangement creates an electrical signal proportional to heat flux intensity, and largely independent of temperature. The sensors are thermally grounded to allow a temperature difference to develop across the thermal resistor, and are cooled by a heat sink to maintain an acceptable operating temperature.

Recov'Heat: An estimation tool of urban waste heat recovery potential in sustainable cities

NASA Astrophysics Data System (ADS)

Goumba, Alain; Chiche, Samuel; Guo, Xiaofeng; Colombert, Morgane; Bonneau, Patricia

2017-02-01

Waste heat recovery is considered as an efficient way to increase carbon-free green energy utilization and to reduce greenhouse gas emission. Especially in urban area, several sources such as sewage water, industrial process, waste incinerator plants, etc., are still rarely explored. Their integration into a district heating system providing heating and/or domestic hot water could be beneficial for both energy companies and local governments. EFFICACITY, a French research institute focused on urban energy transition, has developed an estimation tool for different waste heat sources potentially explored in a sustainable city. This article presents the development method of such a decision making tool which, by giving both energetic and economic analysis, helps local communities and energy service companies to make preliminary studies in heat recovery projects.

Innovative heating of large-size automotive Li-ion cells

NASA Astrophysics Data System (ADS)

Yang, Xiao-Guang; Liu, Teng; Wang, Chao-Yang

2017-02-01

Automotive Li-ion cells are becoming much larger and thicker in order to reduce the cell count and increase battery reliability, posing a new challenge to battery heating from the cold ambient due to poor through-plane heat transfer across a cell's multiple layers of electrodes and separators. In this work, widely used heating methods, including internal heating using the cell's resistance and external heating by resistive heaters, are compared with the recently developed self-heating Li-ion battery (SHLB) with special attention to the heating speed and maximum local temperature critical to battery safety. Both conventional methods are found to be slow due to low heating power required to maintain battery safety. The heating power in the external heating method is limited by the risk of local over-heating, in particular for thick cells. As a result, the external heating method is restricted to ∼20 min slow heating for a 30 °C temperature rise. In contrast, the SHLB is demonstrated to reach a heating speed of 1-2 °C/sec, ∼40 times faster for large-size thick cells, with nearly 100% heating efficiency and spatially uniform heating free from safety concerns.

Influence of Oil on Refrigerant Evaporator Performance

NASA Astrophysics Data System (ADS)

Kim, Jong-Soo; Nagata, Karsuya; Katsuta, Masafumi; Tomosugi, Hiroyuki; Kikuchi, Kouichiro; Horichi, Toshiaki

In vapor compression refrigeration system using oil-lubricated compressors, some amount of oil is always circulated through the system. Oil circulation can have a significant influence on the evaporator performance of automotive air conditioner which is especially required to cool quickly the car interior after a period standing in the sun. An experimental investigation was carried out an electrically heated horizontal tube to measure local heat transfer coefficients for various flow rates and heat fluxes during forced convection boiling of pure refrigerant R12 and refrigerant-oil mixtures (0-11% oil concentration by weight) and the results were compared with oil free performance. Local heat transfer coefficients increased at the region of low vapor quality by the addition of oil. On the other hand, because the oil-rich liquid film was formed on the heat transfer surface, heat transfer coefficients gradually decreased as the vapor quality became higher. Average heat transfer coefficient reached a maximum at about 4% oil concentration and this trend agreed well with the results of Green and Furse. Previous correlations, using the properties of the refrigerant-oil mixture, could not predict satisfactorily the local heat transfer coefficients data. New correlation modified by oil concentration factor was developed for predicting the corresponding heat transfer coefficient for refrigerant-oil mixture convection boiling. The maximum percent deviation between predicted and measured heat transfer coefficient was within ±30%.

Effects of finite wall thickness and sinusoidal heating on convection in nanofluid-saturated local thermal non-equilibrium porous cavity

NASA Astrophysics Data System (ADS)

Alsabery, A. I.; Chamkha, A. J.; Saleh, H.; Hashim, I.; Chanane, B.

2017-03-01

The effects of finite wall thickness and sinusoidal heating on convection in a nanofluid-saturated local thermal non-equilibrium (LTNE) porous cavity are studied numerically using the finite difference method. The finite thickness vertical wall of the cavity is maintained at a constant temperature and the right wall is heated sinusoidally. The horizontal insulated walls allow no heat transfer to the surrounding. The Darcy law is used along with the Boussinesq approximation for the flow. Water-based nanofluids with Cu nanoparticles are chosen for investigation. The results of this study are obtained for various parameters such as the Rayleigh number, periodicity parameter, nanoparticles volume fraction, thermal conductivity ratio, ratio of wall thickness to its height and the modified conductivity ratio. Explanation for the influence of the various above-mentioned parameters on the streamlines, isotherms, local Nusselt number and the weighted average heat transfer is provided with regards to the thermal conductivities of nanoparticles suspended in the pure fluid and the porous medium. It is shown that the overall heat transfer is significantly increased with the relative non-uniform heating. Further, the convection heat transfer is shown to be inhibited by the presence of the solid wall. The results have possible applications in the heat-storage fluid-saturated porous systems and the applications of the high power heat transfer.

Electroless-plating technique for fabricating thin-wall convective heat-transfer models

NASA Technical Reports Server (NTRS)

Avery, D. E.; Ballard, G. K.; Wilson, M. L.

1984-01-01

A technique for fabricating uniform thin-wall metallic heat-transfer models and which simulates a Shuttle thermal protection system tile is described. Two 6- by 6- by 2.5-in. tiles were fabricated to obtain local heat transfer rates. The fabrication process is not limited to any particular geometry and results in a seamless thin-wall heat-transfer model which uses a one-wire thermocouple to obtain local cold-wall heat-transfer rates. The tile is relatively fragile because of the brittle nature of the material and the structural weakness of the flat-sided configuration; however, a method was developed and used for repairing a cracked tile.

Computational Study of Inbore and Inflight Heating for the 105MM, M774 Projectile Modified Swept Fin.

DTIC Science & Technology

1984-08-01

local 1* H. A. Dwyjer, R. J. K~ee, and B. R., Sanderse, "Adaptive Gr’id Method for’ ProbZe s in Ftuid Mechanie and Heat Transfer," 44.AL...A a.4 VoZ . 18...within the fin, heat conduction at the fin root into the pro- jectile body , and surface heat transfer at the fin tip. Other limitations in the heat...Figures 17a,b and 18a,b. From these figures the effect appears to be localized in the trailing edge region and no influence at the critical area near

Targeted Prostate Thermal Therapy with Catheter-Based Ultrasound Devices and MR Thermal Monitoring

NASA Astrophysics Data System (ADS)

Diederich, Chris; Ross, Anthony; Kinsey, Adam; Nau, Will H.; Rieke, Viola; Butts Pauly, Kim; Sommer, Graham

2006-05-01

Catheter-based ultrasound devices have significant advantages for thermal therapy procedures, including potential for precise spatial and dynamic control of heating patterns to conform to targeted volumes. Interstitial and transurethral ultrasound applicators, with associated treatment strategies, were developed for thermal ablation of prostate combined with MR thermal monitoring. Four types of multielement transurethral applicators were devised, each with different levels of selectivity and intended therapeutic goals: sectored tubular transducer devices with fixed directional heating patterns; planar and lightly focused curvilinear devices with narrow heating patterns; and multi-sectored tubular devices capable of dynamic angular control without applicator movement. These devices are integrated with a 4 mm delivery catheter, incorporate an inflatable cooling balloon (10 mm OD) for positioning within the prostate and capable of rotation via an MR-compatible motor. Similarly, interstitial devices (2.4 mm OD) have been developed for percutaneous implantation with fixed directional heating patterns (e.g., 180 deg.). In vivo experiments in canine prostate (n=15) under MR temperature imaging were used to evaluate the heating technology and develop treatment strategies. MR thermal imaging in a 0.5 T interventional MRI was used to monitor temperature contours and thermal dose in multiple slices through the target volume. Sectored transurethral devices produce directional coagulation zones, extending 15-20 mm radial distance to the outer prostate capsule. The curvilinear applicator produces distinct 2-3 mm wide lesions, and with sequential rotation and modulated dwell time can precisely conform thermal ablation to selected areas or the entire prostate gland. Multi-sectored transurethral applicators can dynamically control the angular heating profile and target large regions of the gland in short treatment times without applicator manipulation. Interstitial implants with directional devices can be used to effectively ablate the posterior peripheral zone of the gland while protecting the rectum. An implant with multi-sectored interstitial devices can effectively control the angular heating pattern without applicator rotation. The MR derived 52 °C and lethal thermal dose contours (t43=240 min) allowed for real-time control of the applicators and effectively defined the extent of thermal damage. Catheter-based ultrasound devices, combined with MR thermal monitoring, can produce relatively fast and precise thermal ablation of prostate, with potential for treatment of cancer or BPH.

The theory precision analyse of RFM localization of satellite remote sensing imagery

NASA Astrophysics Data System (ADS)

Zhang, Jianqing; Xv, Biao

2009-11-01

The tradition method of detecting precision of Rational Function Model(RFM) is to make use of a great deal check points, and it calculates mean square error through comparing calculational coordinate with known coordinate. This method is from theory of probability, through a large number of samples to statistic estimate value of mean square error, we can think its estimate value approaches in its true when samples are well enough. This paper is from angle of survey adjustment, take law of propagation of error as the theory basis, and it calculates theory precision of RFM localization. Then take the SPOT5 three array imagery as experiment data, and the result of traditional method and narrated method in the paper are compared, while has confirmed tradition method feasible, and answered its theory precision question from the angle of survey adjustment.

Numerical modeling of heat transfer in the fuel oil storage tank at thermal power plant

NASA Astrophysics Data System (ADS)

Kuznetsova, Svetlana A.

2015-01-01

Presents results of mathematical modeling of convection of a viscous incompressible fluid in a rectangular cavity with conducting walls of finite thickness in the presence of a local source of heat in the bottom of the field in terms of convective heat exchange with the environment. A mathematical model is formulated in terms of dimensionless variables "stream function - vorticity vector speed - temperature" in the Cartesian coordinate system. As the results show the distributions of hydrodynamic parameters and temperatures using different boundary conditions on the local heat source.

Evaluation of CFD Turbulent Heating Prediction Techniques and Comparison With Hypersonic Experimental Data

NASA Technical Reports Server (NTRS)

Dilley, Arthur D.; McClinton, Charles R. (Technical Monitor)

2001-01-01

Results from a study to assess the accuracy of turbulent heating and skin friction prediction techniques for hypersonic applications are presented. The study uses the original and a modified Baldwin-Lomax turbulence model with a space marching code. Grid converged turbulent predictions using the wall damping formulation (original model) and local damping formulation (modified model) are compared with experimental data for several flat plates. The wall damping and local damping results are similar for hot wall conditions, but differ significantly for cold walls, i.e., T(sub w) / T(sub t) < 0.3, with the wall damping heating and skin friction 10-30% above the local damping results. Furthermore, the local damping predictions have reasonable or good agreement with the experimental heating data for all cases. The impact of the two formulations on the van Driest damping function and the turbulent eddy viscosity distribution for a cold wall case indicate the importance of including temperature gradient effects. Grid requirements for accurate turbulent heating predictions are also studied. These results indicate that a cell Reynolds number of 1 is required for grid converged heating predictions, but coarser grids with a y(sup +) less than 2 are adequate for design of hypersonic vehicles. Based on the results of this study, it is recommended that the local damping formulation be used with the Baldwin-Lomax and Cebeci-Smith turbulence models in design and analysis of Hyper-X and future hypersonic vehicles.

Dilution of Precision as a Geometry Metric for Swarm Relative Localization

DTIC Science & Technology

2017-11-01

algorithm 2.2 Intuitive DOP Illustration Before proceeding with a quantitative definition of DOP, an intuitive example will be given to illustrate the...in Fig. 11 4.2.2 Constant DOP Example Compare the results of the previous simulation to those shown in Figs. 13 and 14. Instead of only scaling...ARL-TR-8200 ● NOV 2017 US Army Research Laboratory Dilution of Precision as a Geometry Metric for Swarm Relative Localization

Report on SNL RCBC control options

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ponciroli, R.; Vilim, R. B.

The attractive performance of the S-CO 2 recompression cycle arises from the thermo-physical properties of carbon dioxide near the critical point. However, to ensure efficient operation of the cycle near the critical point, precise control of the heat removal rate by the Printed Circuit Heat Exchanger (PCHE) upstream of the main compressor is required. Accomplishing this task is not trivial because of the large variations in fluid properties with respect to temperature and pressure near the critical point. The use of a model-based approach for the design of a robust feedback regulator is being investigated to achieve acceptable control ofmore » heat removal rate at different operating conditions. A first step in this procedure is the development of a dynamic model of the heat exchanger. In this work, a one-dimensional (1-D) control-oriented model of the PCHE was developed using the General Plant Analyzer and System Simulator (GPASS) code. GPASS is a transient simulation code that supports analysis and control of power conversion cycles based on the S-CO 2 Brayton cycle. This modeling capability was used this fiscal year to analyze experiment data obtained from the heat exchanger in the SNL recompression Brayton cycle. The analysis suggested that the error in the water flowrate measurement was greater than required for achieving precise control of heat removal rate. Accordingly, a new water flowmeter was installed, significantly improving the quality of the measurement. Comparison of heat exchanger measurements in subsequent experiments with code simulations yielded good agreement establishing a reliable basis for the use of the GPASS PCHE model for future development of a model-based feedback controller.« less

Precise carbon control of fabricated stainless steel

DOEpatents

Nilsen, R.J.

1975-12-01

A process is described for controlling the carbon content of fabricated stainless steel components including the steps of heat treating the component in hydrogen atmospheres of varying dewpoints and carbon potentials.

Eliminating Mercury Thermometers from the Lab.

ERIC Educational Resources Information Center

Everett, T. Stephen

1997-01-01

Compares the precision, accuracy, and response of a cooking probe to a standard mercury thermometer in side-by-side heating in temperature baths, simple and fractional distillations, and melting point determination. (DDR)

Investigation of heat flux on aerodynamic body in supersonic gas flow with local energy deposition

NASA Astrophysics Data System (ADS)

Dobrov, Y. V.; Lashkov, V. A.; Mashek, I. Ch.; Khoronzhuk, R. S.

2018-05-01

Existence and intensive growth of heat flux on a vehicle is one of the main problems in hypersonic flight. Experimental study of heat flux in the stagnation point of a blunt cylinder in supersonic flow was made using gradient heat flux sensor. It was found that a transfer function of the measuring system should be used for obtaining data at fast-changing heat flux measurements. It was established that it was possible to produce a short-term heat transfer from the surface of streamlined body with the help of microwave discharge. Numerical simulation showed that it is possible to change nature of the flow by means of local energy deposition in case of streamlined wedge.

Flexible non-diffractive vortex microscope for three-dimensional depth-enhanced super-localization of dielectric, metal and fluorescent nanoparticles

NASA Astrophysics Data System (ADS)

Bouchal, Petr; Bouchal, Zdeněk

2017-10-01

In the past decade, probe-based super-resolution using temporally resolved localization of emitters became a groundbreaking imaging strategy in fluorescence microscopy. Here we demonstrate a non-diffractive vortex microscope (NVM), enabling three-dimensional super-resolution fluorescence imaging and localization and tracking of metal and dielectric nanoparticles. The NVM benefits from vortex non-diffractive beams (NBs) creating a double-helix point spread function that rotates under defocusing while maintaining its size and shape unchanged. Using intrinsic properties of the NBs, the dark-field localization of weakly scattering objects is achieved in a large axial range exceeding the depth of field of the microscope objective up to 23 times. The NVM was developed using an upright microscope Nikon Eclipse E600 operating with a spiral lithographic mask optimized using Fisher information and built into an add-on imaging module or microscope objective. In evaluation of the axial localization accuracy the root mean square error below 18 nm and 280 nm was verified over depth ranges of 3.5 μm and 13.6 μm, respectively. Subwavelength gold and polystyrene beads were localized with isotropic precision below 10 nm in the axial range of 3.5 μm and the axial precision reduced to 30 nm in the extended range of 13.6 μm. In the fluorescence imaging, the localization with isotropic precision below 15 nm was demonstrated in the range of 2.5 μm, whereas in the range of 8.3 μm, the precision of 15 nm laterally and 30-50 nm axially was achieved. The tracking of nanoparticles undergoing Brownian motion was demonstrated in the volume of 14 × 10 × 16 μm3. Applicability of the NVM was tested by fluorescence imaging of LW13K2 cells and localization of cellular proteins.

Process optimization of joining by upset bulging with local heating

NASA Astrophysics Data System (ADS)

Rusch, Michael; Almohallami, Amer; Sviridov, Alexander; Bonk, Christian; Behrens, Bernd-Arno; Bambach, Markus

2017-10-01

Joining by upset bulging is a mechanical joining method where axial load is applied to a tube to form two revolving bulges, which clamp the parts to be joined and create a force and form fit. It can be used to join tubes with other structures such as sheets, plates, tubes or profiles of the same or different materials. Other processes such as welding are often limited in joining multi-material assemblies or high-strength materials. With joining by upset bulging at room temperature, the main drawback is the possible initiation of damage (cracks) in the inner buckling zone because of high local stresses and strains. In this paper, a method to avoid the formation of cracks is introduced. Before forming the bulge the tube is locally heated by an induction coil. For the construction steel (E235+N) a maximum temperature of 700 °C was used to avoid phase transformation. For the numerical study of the process the mechanical properties of the tube material were examined at different temperatures and strain rates to determine its flow curves. A parametrical FE model was developed to simulate the bulging process with local heating. Experiments with local heating were executed and metallographic studies of the bulging area were conducted. While specimens heated to 500 °C showed small cracks left, damage-free flanges could be created at 600 and 700 °C. Static testing of damage-free bulges showed improvements in tensile strength and torsion strength compared to bulges formed at room-temperature, while bending and compression behavior remained nearly unchanged. In cyclic testing the locally heated specimens underwent about 3.7 times as many cycles before failure as the specimens formed at room temperature.

Ultrafast collisional ion heating by electrostatic shocks.

PubMed

Turrell, A E; Sherlock, M; Rose, S J

2015-11-13

High-intensity lasers can be used to generate shockwaves, which have found applications in nuclear fusion, proton imaging, cancer therapies and materials science. Collisionless electrostatic shocks are one type of shockwave widely studied for applications involving ion acceleration. Here we show a novel mechanism for collisionless electrostatic shocks to heat small amounts of solid density matter to temperatures of ∼keV in tens of femtoseconds. Unusually, electrons play no direct role in the heating and it is the ions that determine the heating rate. Ions are heated due to an interplay between the electric field of the shock, the local density increase during the passage of the shock and collisions between different species of ion. In simulations, these factors combine to produce rapid, localized heating of the lighter ion species. Although the heated volume is modest, this would be one of the fastest heating mechanisms discovered if demonstrated in the laboratory.

Modality-specific peripheral antinociceptive effects of μ-opioid agonists on heat and mechanical stimuli: Contribution of sigma-1 receptors.

PubMed

Montilla-García, Ángeles; Perazzoli, Gloria; Tejada, Miguel Á; González-Cano, Rafael; Sánchez-Fernández, Cristina; Cobos, Enrique J; Baeyens, José M

2018-06-01

Morphine induces peripherally μ-opioid-mediated antinociception to heat but not to mechanical stimulation. Peripheral sigma-1 receptors tonically inhibit μ-opioid antinociception to mechanical stimuli, but it is unknown whether they modulate μ-opioid heat antinociception. We hypothesized that sigma-1 receptors might play a role in the modality-specific peripheral antinociceptive effects of morphine and other clinically relevant μ-opioid agonists. Mechanical nociception was assessed in mice with the paw pressure test (450 g), and heat nociception with the unilateral hot plate (55 °C) test. Local peripheral (intraplantar) administration of morphine, buprenorphine or oxycodone did not induce antinociception to mechanical stimulation but had dose-dependent antinociceptive effects on heat stimuli. Local sigma-1 antagonism unmasked peripheral antinociception by μ-opioid agonists to mechanical stimuli, but did not modify their effects on heat stimulation. TRPV1+ and IB4+ cells are segregated populations of small neurons in the dorsal root ganglia (DRG) and the density of sigma-1 receptors was higher in IB4+ cells than in the rest of small nociceptive neurons. The in vivo ablation of TRPV1-expressing neurons with resiniferatoxin did not alter IB4+ neurons in the DRG, mechanical nociception, or the effects of sigma-1 antagonism on local morphine antinociception in this type of stimulus. However, it impaired the responses to heat stimuli and the effect of local morphine on heat nociception. In conclusion, peripheral opioid antinociception to mechanical stimuli is limited by sigma-1 tonic inhibitory actions, whereas peripheral opioid antinociception to heat stimuli (produced in TRPV1-expressing neurons) is not. Therefore, sigma-1 receptors contribute to the modality-specific peripheral effects of opioid analgesics. Copyright © 2018 The Authors. Published by Elsevier Ltd.. All rights reserved.

OCT-based angiography of human dermal microvascular reactions to local stimuli: Implications for increasing capillary blood collection volumes.

PubMed

Men, Shaojie; Wong, Jennifer Manyu; Welch, Emily J; Xu, Jingjiang; Song, Shaozhen; Deegan, Anthony J; Ravichander, Aarthi; Casavant, Benjamin; Berthier, Erwin; Wang, Ruikang K

2018-05-25

To measure and compare microvascular responses within the skin of the upper arm to local stimuli, such as heating or rubbing, through the use of optical coherence tomography angiography (OCTA), and to investigate its impact on blood volume collection. With the use of heat packs or rubbing, local stimulation was applied to the skin of either the left or right upper arm. Data from the stimulated sites were obtained using OCTA comparing pre- and post-stimulation microvascular parameters, such as vessel density, mean vessel diameter, and mean avascular pore size. Additionally, blood was collected using a newly designed collection device and volume was recorded to evaluate the effect of the skin stimulation. Nineteen subjects were recruited for local stimulation study (including rubbing and heating) and 21 subjects for blood drawn study. Of these subjects, 14 agreed to participate in both studies. OCTA was successful in monitoring and measuring minute changes in the microvasculature of the stimulated skin. Compared to baseline, significant changes after local heating and rubbing were respectively found in vessel density (16% [P = 0.0004] and 33% [P < 0.0001] increase), mean vessel diameter (14% and 11% increase) and mean avascular pore size (5% [P = 0.0068] and 8% [P = 0.0005] decrease) after stimulations. A gradual recovery was recorded for each parameter, with no difference being measured after 30 minutes. Blood collection volumes significantly increased after stimulations of heating (48% increase; P = 0.049) and rubbing (78% increase; P = 0.048). Significant correlations were found between blood volume and microvascular parameters except mean avascular pore size under the heating condition. OCTA can provide important information regarding microvascular adaptations to local stimuli. With that, both heating and rubbing of the skin have positive effects on blood collection capacity, with rubbing having the most significant effect. Lasers Surg. Med. © 2018 Wiley Periodicals, Inc. © 2018 Wiley Periodicals, Inc.

Anchor-Free Localization Method for Mobile Targets in Coal Mine Wireless Sensor Networks

PubMed Central

Pei, Zhongmin; Deng, Zhidong; Xu, Shuo; Xu, Xiao

2009-01-01

Severe natural conditions and complex terrain make it difficult to apply precise localization in underground mines. In this paper, an anchor-free localization method for mobile targets is proposed based on non-metric multi-dimensional scaling (Multi-dimensional Scaling: MDS) and rank sequence. Firstly, a coal mine wireless sensor network is constructed in underground mines based on the ZigBee technology. Then a non-metric MDS algorithm is imported to estimate the reference nodes’ location. Finally, an improved sequence-based localization algorithm is presented to complete precise localization for mobile targets. The proposed method is tested through simulations with 100 nodes, outdoor experiments with 15 ZigBee physical nodes, and the experiments in the mine gas explosion laboratory with 12 ZigBee nodes. Experimental results show that our method has better localization accuracy and is more robust in underground mines. PMID:22574048

Anchor-free localization method for mobile targets in coal mine wireless sensor networks.

PubMed

Pei, Zhongmin; Deng, Zhidong; Xu, Shuo; Xu, Xiao

2009-01-01

Severe natural conditions and complex terrain make it difficult to apply precise localization in underground mines. In this paper, an anchor-free localization method for mobile targets is proposed based on non-metric multi-dimensional scaling (Multi-dimensional Scaling: MDS) and rank sequence. Firstly, a coal mine wireless sensor network is constructed in underground mines based on the ZigBee technology. Then a non-metric MDS algorithm is imported to estimate the reference nodes' location. Finally, an improved sequence-based localization algorithm is presented to complete precise localization for mobile targets. The proposed method is tested through simulations with 100 nodes, outdoor experiments with 15 ZigBee physical nodes, and the experiments in the mine gas explosion laboratory with 12 ZigBee nodes. Experimental results show that our method has better localization accuracy and is more robust in underground mines.

Computational simulation of weld microstructure and distortion by considering process mechanics

NASA Astrophysics Data System (ADS)

Mochizuki, M.; Mikami, Y.; Okano, S.; Itoh, S.

2009-05-01

Highly precise fabrication of welded materials is in great demand, and so microstructure and distortion controls are essential. Furthermore, consideration of process mechanics is important for intelligent fabrication. In this study, the microstructure and hardness distribution in multi-pass weld metal are evaluated by computational simulations under the conditions of multiple heat cycles and phase transformation. Because conventional CCT diagrams of weld metal are not available even for single-pass weld metal, new diagrams for multi-pass weld metals are created. The weld microstructure and hardness distribution are precisely predicted when using the created CCT diagram for multi-pass weld metal and calculating the weld thermal cycle. Weld distortion is also investigated by using numerical simulation with a thermal elastic-plastic analysis. In conventional evaluations of weld distortion, the average heat input has been used as the dominant parameter; however, it is difficult to consider the effect of molten pool configurations on weld distortion based only on the heat input. Thus, the effect of welding process conditions on weld distortion is studied by considering molten pool configurations, determined by temperature distribution and history.

User's manual for the ALS base heating prediction code, volume 2

NASA Technical Reports Server (NTRS)

Reardon, John E.; Fulton, Michael S.

1992-01-01

The Advanced Launch System (ALS) Base Heating Prediction Code is based on a generalization of first principles in the prediction of plume induced base convective heating and plume radiation. It should be considered to be an approximate method for evaluating trends as a function of configuration variables because the processes being modeled are too complex to allow an accurate generalization. The convective methodology is based upon generalizing trends from four nozzle configurations, so an extension to use the code with strap-on boosters, multiple nozzle sizes, and variations in the propellants and chamber pressure histories cannot be precisely treated. The plume radiation is more amenable to precise computer prediction, but simplified assumptions are required to model the various aspects of the candidate configurations. Perhaps the most difficult area to characterize is the variation of radiation with altitude. The theory in the radiation predictions is described in more detail. This report is intended to familiarize a user with the interface operation and options, to summarize the limitations and restrictions of the code, and to provide information to assist in installing the code.

Reliable low precision simulations in land surface models

NASA Astrophysics Data System (ADS)

Dawson, Andrew; Düben, Peter D.; MacLeod, David A.; Palmer, Tim N.

2017-12-01

Weather and climate models must continue to increase in both resolution and complexity in order that forecasts become more accurate and reliable. Moving to lower numerical precision may be an essential tool for coping with the demand for ever increasing model complexity in addition to increasing computing resources. However, there have been some concerns in the weather and climate modelling community over the suitability of lower precision for climate models, particularly for representing processes that change very slowly over long time-scales. These processes are difficult to represent using low precision due to time increments being systematically rounded to zero. Idealised simulations are used to demonstrate that a model of deep soil heat diffusion that fails when run in single precision can be modified to work correctly using low precision, by splitting up the model into a small higher precision part and a low precision part. This strategy retains the computational benefits of reduced precision whilst preserving accuracy. This same technique is also applied to a full complexity land surface model, resulting in rounding errors that are significantly smaller than initial condition and parameter uncertainties. Although lower precision will present some problems for the weather and climate modelling community, many of the problems can likely be overcome using a straightforward and physically motivated application of reduced precision.

Experimental aerodynamic heating to simulated space shuttle tiles in laminar and turbulent boundary layers with variable flow angles at a nominal Mach number of 7. M.S. Thesis - George Washington Univ., Nov. 1983

NASA Technical Reports Server (NTRS)

Avery, D. E.

1985-01-01

The heat transfer to simulated shuttle thermal protection system tiles was investigated experimentally by using a highly instrumented metallic thin wall tile arranged with other metal tiles in a staggered tile array. Cold wall heating rate data for laminar and turbulent flow were obtained in the Langley 8 foot high Temperature Tunnel at a nominal Mach number of 7, a nominal total temperature of 3300R, a free stream unit Reynolds number from 3.4 x 10 sup 5 to 2.2 10 sup 6 per foot, and a free stream dynamic pressure from 2.1 to 9.0 psia. Experimental data are presented to illustrate the effects of flow angularity and gap width on both local peak heating and overall heating loads. For the conditions of the present study, the results show that localized and total heating are sensitive to changes in flow angle only for the test conditions of turbulent boundary layer flow with high kinetic energy and that a flow angle from 30 deg to 50 deg will minimize the local heating.

Method and apparatus for obtaining enhanced production rate of thermal chemical reactions

DOEpatents

Tonkovich, Anna Lee Y [Pasco, WA; Wang, Yong [Richland, WA; Wegeng, Robert S [Richland, WA; Gao, Yufei [Kennewick, WA

2003-04-01

The present invention is a method and apparatus (vessel) for providing a heat transfer rate from a reaction chamber through a wall to a heat transfer chamber substantially matching a local heat transfer rate of a catalytic thermal chemical reaction. The key to the invention is a thermal distance defined on a cross sectional plane through the vessel inclusive of a heat transfer chamber, reaction chamber and a wall between the chambers. The cross sectional plane is perpendicular to a bulk flow direction of the reactant stream, and the thermal distance is a distance between a coolest position and a hottest position on the cross sectional plane. The thermal distance is of a length wherein the heat transfer rate from the reaction chamber to the heat transfer chamber substantially matches the local heat transfer rate.

The local heat transfer mathematical model between vibrated fluidized beds and horizontal tubes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhu, Xuejun; College of Biology and Chemical Engineering, Panzhihua University, Panzhihua 617000; Ye, Shichao

2008-05-15

A dimensionless mathematical model is proposed to predict the local heat transfer coefficients between vibrated fluidized beds and immersed horizontal tubes, and the effects of the thickness of gas film and the contact time of particle packets are well considered. Experiments using the glass beads (the average diameter bar d{sub p}=1.83mm) were conducted in a two-dimensional vibrated fluidized bed (240 mm x 80 mm). The local heat transfer law between vibrated fluidized bed and horizontal tube surface has been investigated. The results show that the values of theoretical prediction are in good agreement with experimental data, so the model ismore » able to predict the local heat transfer coefficients between vibrated fluidized beds and immersed horizontal tubes reasonably well, and the error is in range of {+-}15%. The results can provide references for future designing and researching on the vibrated fluidized beds with immersed horizontal tubes. (author)« less

Compact Directional Microwave Antenna for Localized Heating

NASA Technical Reports Server (NTRS)

Fink, Patrick W.; Lin, Gregory Y.; Chu, Andrew W.; Dobbins, Justin A.; Arndt, G. Dickey; Ngo, Phong

2008-01-01

A directional, catheter-sized cylindrical antenna has been developed for localized delivery of microwave radiation for heating (and thus killing) diseased tissue without excessively heating nearby healthy tissue. By "localized" is meant that the antenna radiates much more in a selected azimuthal direction than in the opposite radial direction, so that it heats tissue much more on one side than it does on the opposite side. This antenna can be inserted using either a catheter or a syringe. A 2.4-mm prototype was tested, although smaller antennas are possible. Prior compact, cylindrical antennas designed for therapeutic localized hyperthermia do not exhibit such directionality; that is, they radiate in approximately axisymmetric patterns. Prior directional antennas designed for the same purpose have been, variously, (1) too large to fit within catheters or (2) too large, after deployment from catheters, to fit within the confines of most human organs. In contrast, the present antenna offers a high degree of directionality and is compact enough to be useable as a catheter in some applications.

Biomass district heating methodology and pilot installations for public buildings groups

NASA Astrophysics Data System (ADS)

Chatzistougianni, N.; Giagozoglou, E.; Sentzas, K.; Karastergios, E.; Tsiamitros, D.; Stimoniaris, D.; Stomoniaris, A.; Maropoulos, S.

2016-11-01

The objective of the paper is to show how locally available biomass can support a small-scale district heating system of public buildings, especially when taking into account energy audit in-situ measurements and energy efficiency improvement measures. The step-by-step methodology is presented, including the research for local biomass availability, the thermal needs study and the study for the biomass district heating system, with and without energy efficiency improvement measures.

Photoinduced local heating in silica photonic crystals for fast and reversible switching.

PubMed

Gallego-Gómez, Francisco; Blanco, Alvaro; López, Cefe

2012-12-04

Fast and reversible photonic-bandgap tunability is achieved in silica artificial opals by local heating. The effect is fully reversible as heat rapidly dissipates through the non-irradiated structure without active cooling and water is readsorbed. The performance is strongly enhanced by decreasing the photoirradiated opal volume, allowing bandgap shifts of 12 nm and response times of 20 ms. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Microwave Dielectric Heating of Drops in Microfluidic Devices†

PubMed Central

Issadore, David; Humphry, Katherine J.; Brown, Keith A.; Sandberg, Lori; Weitz, David; Westervelt, Robert M.

2010-01-01

We present a technique to locally and rapidly heat water drops in microfluidic devices with microwave dielectric heating. Water absorbs microwave power more efficiently than polymers, glass, and oils due to its permanent molecular dipole moment that has a large dielectric loss at GHz frequencies. The relevant heat capacity of the system is a single thermally isolated picoliter drop of water and this enables very fast thermal cycling. We demonstrate microwave dielectric heating in a microfluidic device that integrates a flow-focusing drop maker, drop splitters, and metal electrodes to locally deliver microwave power from an inexpensive, commercially available 3.0 GHz source and amplifier. The temperature of the drops is measured by observing the temperature dependent fluorescence intensity of cadmium selenide nanocrystals suspended in the water drops. We demonstrate characteristic heating times as short as 15 ms to steady-state temperatures as large as 30°C above the base temperature of the microfluidic device. Many common biological and chemical applications require rapid and local control of temperature, such as PCR amplification of DNA, and can benefit from this new technique. PMID:19495453

Heat Transfer Analysis of Localized Heat-Treatment for Grade 91 Steel

NASA Astrophysics Data System (ADS)

Walker, Jacob D.

Many of the projects utilizing Grade 91 steel are large in scale, therefore it is necessary to assemble on site. The assembly of the major pieces requires welding in the assembly; this drastically changes the superior mechanical properties of Grade 91 steel that it was specifically developed for. Therefore, because of the adverse effects of welding on the mechanical properties of Grade 91, it is necessary to do a localized post weld heat treatment. As with most metallic materials grade 91 steel requires a very specific heat treatment process. This process includes a specific temperature and duration at that temperature to achieve the heat treatment desired. Extensive research has been done to determine the proper temperatures and duration to provide the proper microstructure for the superior mechanical properties that are inherent to Grade 91 steel. The welded sections are typically large structures that require local heat treatments and cannot be placed in an oven. The locations of these structures vary from indoors in a controlled environment to outdoors with unpredictable environments. These environments can be controlled somewhat, however in large part the surrounding conditions are unchangeable. Therefore, there is a need to develop methods to accurately apply the surrounding conditions and geometries to a theoretical model in order to provide the proper requirements for the local heat treatment procedure. Within this requirement is the requirement to define unknowns used in the heat transfer equations so that accurate models can be produced and accurate results predicted. This study investigates experimentally and numerically the heat transfer and temperature fields of Grade 91 piping in a local heat treatment. The objective of this thesis research is to determine all of the needed heat transfer coefficients. The appropriate heat transfer coefficients are determined through the inverse heat conduction method utilizing a ceramic heat blanket. This will be done through an inverse method by collecting actual data from different conditions and temperatures. Then the heat transfer coefficients are used to set up a model to determine the appropriate post-weld heat treatment conditions for Grade 91 steel. This will enable one to use the derived coefficients to run a forward analysis with the specific geometry and conditions they will encounter in the heat treatment process for their application. The analysis will provide a theoretical determination of time and temperatures needed to maintain the temperature for the proper time needed to properly heat treat the welded section in the desired areas that have been joined together through a welding process. Finally time and temperature combinations are compared with experimentally measured data. The forward model code applied to the parameters of the heat-treatment can then appropriately assist to determine the proper post-weld heat treatment conditions for the desired toughness and creep properties. This research is very beneficial to the joining of metals industry because it provides a way to ensure the method used to heat treat the welded section is being properly done, and the required heat treatment is achieved. It is applicable to many different geometries so that it can be modified to specific situations.

[Comparison of dentomaxillary pantomography and periapical radiographs with horizontal tube shift in localizing the impacted teeth].

PubMed

Wang, Sun; Fan, Lin-feng

2005-04-01

To compare the clinic value between dentomaxillary pantomography and periapical radiographs in localization of the impacted teeth. 43 impacted teeth were localized with both dentomaxillary pantomography technique and periapical radiographs with horizontal tube shift which is clinically widely used. And a comparison between the two methods was carried out using Chi square test. Both dentomaxillary pantomography and periapical radiographs with horizontal tube shift can relatively precisely demonstrate the position of the impacted teeth. The percentage of the cases which the image and the result of surgery was consistent in the two methods was 93.02% and 95.35% (P>0.05) respectively. There was no statistical difference between the two groups. Dentomaxillary pantomography can precisely localize the impacted teeth.

The Dynamics of the Local Group in the Era of Precision Astrometry

NASA Astrophysics Data System (ADS)

Besla, Gurtina; Garavito-Camargo, Nicolas; Patel, Ekta

2018-06-01

Our understanding of the dynamics of our Local Group of galaxies has changed dramatically over the past few years owing to significant advancements in astrometry and our theoretical understanding of galaxy structure. New surveys now enable us to map the 3D structure of our Milky Way and the dynamics of tracers of its dark matter distribution, like globular clusters, satellite galaxies and streams, with unprecedented precision. Some results have met with controversy, challenging preconceived notions of the orbital dynamics of key components of the Local Group. I will provide an overview of this evolving picture of our Local Group and outline how we can test the cold dark matter paradigm in the era of Gaia, LSST and JWST.

Tower reactors for bioconversion of lignocellulosic material

DOEpatents

Nguyen, Quang A.

1999-01-01

An apparatus for enzymatic hydrolysis and fermentation of pretreated lignocellulosic material, in the form of a tower bioreactor, having mixers to achieve intermittent mixing of the material. Precise mixing of the material is important for effective heat and mass transfer requirements without damaging or denaturing the enzymes or fermenting microorganisms. The pretreated material, generally in the form of a slurry, is pumped through the bioreactor, either upwards or downwards, and is mixed periodically as it passes through the mixing zones where the mixers are located. For a thin slurry, alternate mixing can be achieved by a pumping loop which also serves as a heat transfer device. Additional heat transfer takes place through the reactor heat transfer jackets.

Tower reactors for bioconversion of lignocellulosic material

DOEpatents

Nguyen, Quang A.

1998-01-01

An apparatus for enzymatic hydrolysis and fermentation of pretreated lignocellulosic material, in the form of a tower bioreactor, having mixers to achieve intermittent mixing of the material. Precise mixing of the material is important for effective heat and mass transfer requirements without damaging or denaturing the enzymes or fermenting microorganisms. The pretreated material, generally in the form of a slurry, is pumped through the bioreactor, either upwards of downwards, and is mixed periodically as it passes through the mixing zones where the mixers are located. For a thin slurry, alternate mixing can be achieved by a pumping loop which also serves as a heat transfer device. Additional heat transfer takes place through the reactor heat transfer jackets.

A comparison between the effects of artificial land cover and anthropogenic heat on a localized heavy rain event in 2008 in Zoshigaya, Tokyo, Japan

NASA Astrophysics Data System (ADS)

Souma, Kazuyoshi; Tanaka, Kenji; Suetsugi, Tadashi; Sunada, Kengo; Tsuboki, Kazuhisa; Shinoda, Taro; Wang, Yuqing; Sakakibara, Atsushi; Hasegawa, Koichi; Moteki, Qoosaku; Nakakita, Eiichi

2013-10-01

5 August 2008, a localized heavy rainfall event caused a rapid increase in drainpipe discharge, which killed five people working in a drainpipe near Zoshigaya, Tokyo. This study compared the effects of artificial land cover and anthropogenic heat on this localized heavy rainfall event based on three ensemble experiments using a cloud-resolving model that includes realistic urban features. The first experiment CTRL (control) considered realistic land cover and urban features, including artificial land cover, anthropogenic heat, and urban geometry. In the second experiment NOAH (no anthropogenic heat), anthropogenic heat was ignored. In the third experiment NOLC (no land cover), urban heating from artificial land cover was reduced by keeping the urban geometry but with roofs, walls, and roads of artificial land cover replaced by shallow water. The results indicated that both anthropogenic heat and artificial land cover increased the amount of precipitation and that the effect of artificial land cover was larger than that of anthropogenic heat. However, in the middle stage of the precipitation event, the difference between the two effects became small. Weak surface heating in NOAH and NOLC reduced the near-surface air temperature and weakened the convergence of horizontal wind and updraft over the urban areas, resulting in a reduced rainfall amount compared with that in CTRL.

Continuous, edge localized ion heating during non-solenoidal plasma startup and sustainment in a low aspect ratio tokamak

NASA Astrophysics Data System (ADS)

Burke, M. G.; Barr, J. L.; Bongard, M. W.; Fonck, R. J.; Hinson, E. T.; Perry, J. M.; Reusch, J. A.; Schlossberg, D. J.

2017-07-01

Plasmas in the Pegasus spherical tokamak are initiated and grown by the non-solenoidal local helicity injection (LHI) current drive technique. The LHI system consists of three adjacent electron current sources that inject multiple helical current filaments that can reconnect with each other. Anomalously high impurity ion temperatures are observed during LHI with T i,OV  ⩽  650 eV, which is in contrast to T i,OV  ⩽  70 eV from Ohmic heating alone. Spatial profiles of T i,OV indicate an edge localized heating source, with T i,OV ~ 650 eV near the outboard major radius of the injectors and dropping to ~150 eV near the plasma magnetic axis. Experiments without a background tokamak plasma indicate the ion heating results from magnetic reconnection between adjacent injected current filaments. In these experiments, the HeII T i perpendicular to the magnetic field is found to scale with the reconnecting field strength, local density, and guide field, while {{T}\\text{i,\\parallel}} experiences little change, in agreement with two-fluid reconnection theory. This ion heating is not expected to significantly impact the LHI plasma performance in Pegasus, as it does not contribute significantly to the electron heating. However, estimates of the power transfer to the bulk ion are quite large, and thus LHI current drive provides an auxiliary ion heating mechanism to the tokamak plasma.

Continuous, edge localized ion heating during non-solenoidal plasma startup and sustainment in a low aspect ratio tokamak

DOE PAGES

Burke, Marcus G.; Barr, Jayson L.; Bongard, Michael W.; ...

2017-05-16

Plasmas in the Pegasus spherical tokamak are initiated and grown by the non-solenoidal local helicity injection (LHI) current drive technique. The LHI system consists of three adjacent electron current sources that inject multiple helical current filaments that can reconnect with each other. Anomalously high impurity ion temperatures are observed during LHI with T i,OV ≤ 650 eV, which is in contrast to T i,OV ≤ 70 eV from Ohmic heating alone. Spatial profiles of T i,OV indicate an edge localized heating source, with T i,OV ~ 650 eV near the outboard major radius of the injectors and dropping to ~150 eV near the plasma magnetic axis. Experiments without a background tokamak plasma indicate the ion heating results from magnetic reconnection between adjacent injected current filaments. In these experiments, the HeII T i perpendicular to the magnetic field is found to scale with the reconnecting field strength, local density, and guide field, whilemore » $${{T}_{\\text{i},\\parallel}}$$ experiences little change, in agreement with two-fluid reconnection theory. In conclusion, this ion heating is not expected to significantly impact the LHI plasma performance in Pegasus, as it does not contribute significantly to the electron heating. However, estimates of the power transfer to the bulk ion are quite large, and thus LHI current drive provides an auxiliary ion heating mechanism to the tokamak plasma.« less

Ball-and-Socket Mount for Instruments

NASA Technical Reports Server (NTRS)

Kaelber, E.

1986-01-01

Jaws engage instrument precisely but release it readily. Mounting mechanism holds scientific instrument securely, allows instrument to be oriented, and minimizes conduction of heat to and from instrument. Mechanism also allows quick replacement of instrument.

Mitigating Climate Change with Earth Orbital Sunshades

NASA Technical Reports Server (NTRS)

Coverstone, Victoria; Johnson, Les

2015-01-01

An array of rotating sunshades based on emerging solar sail technology will be deployed in a novel Earth orbit to provide near-continuous partial shading of the Earth, reducing the heat input to the atmosphere by blocking a small percentage of the incoming sunlight, and mitigating local weather effects of anticipated climate change over the next century. The technology will provide local cooling relief during extreme heat events (and heating relief during extreme cold events) thereby saving human lives, agriculture, livestock, water and energy needs. A synthesis of the solar sail design, the sails' operational modes, and the selected orbit combine to provide local weather modification.

District heating campaign in Sweden

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stalebrant, R.E.

During the fall of 1994 a district heating campaign was conducted in Sweden. The campaign was initiated because the Swedish district heating companies agreed that it was time to increase knowledge and awareness of district heating among the general public, especially among potential customers. The campaign involved many district heating companies and was organized as a special project. Advertising companies, media advisers, consultants and investigators were also engaged. The campaign was conducted in two stages, a national campaign followed by local campaign was conducted in two stages, a national campaign followed by local campaigns. The national campaign was conducted duringmore » two weeks of November 1994 and comprised advertising on commercial TV and in the press.« less

An experimental and numerical study of endwall heat transfer in a turbine blade cascade including tangential heat conduction analysis

NASA Astrophysics Data System (ADS)

Ratto, Luca; Satta, Francesca; Tanda, Giovanni

2018-06-01

This paper presents an experimental and numerical investigation of heat transfer in the endwall region of a large scale turbine cascade. The steady-state liquid crystal technique has been used to obtain the map of the heat transfer coefficient for a constant heat flux boundary condition. In the presence of two- and three-dimensional flows with significant spatial variations of the heat transfer coefficient, tangential heat conduction could lead to error in the heat transfer coefficient determination, since local heat fluxes at the wall-to-fluid interface tend to differ from point to point and surface temperatures to be smoothed out, thus making the uniform-heat-flux boundary condition difficult to be perfectly achieved. For this reason, numerical simulations of flow and heat transfer in the cascade including the effect of tangential heat conduction inside the endwall have been performed. The major objective of numerical simulations was to investigate the influence of wall heat conduction on the convective heat transfer coefficient determined during a nominal iso-flux heat transfer experiment and to interpret possible differences between numerical and experimental heat transfer results. Results were presented and discussed in terms of local Nusselt number and a convenient wall heat flux function for two values of the Reynolds number (270,000 and 960,000).

Commissioning Procedures for Mechanical Precision and Accuracy in a Dedicated LINAC

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ballesteros-Zebadua, P.; Larrga-Gutierrez, J. M.; Garcia-Garduno, O. A.

2008-08-11

Mechanical precision measurements are fundamental procedures for the commissioning of a dedicated LINAC. At our Radioneurosurgery Unit, these procedures can be suitable as quality assurance routines that allow the verification of the equipment geometrical accuracy and precision. In this work mechanical tests were performed for gantry and table rotation, obtaining mean associated uncertainties of 0.3 mm and 0.71 mm, respectively. Using an anthropomorphic phantom and a series of localized surface markers, isocenter accuracy showed to be smaller than 0.86 mm for radiosurgery procedures and 0.95 mm for fractionated treatments with mask. All uncertainties were below tolerances. The highest contribution tomore » mechanical variations is due to table rotation, so it is important to correct variations using a localization frame with printed overlays. Mechanical precision knowledge would allow to consider the statistical errors in the treatment planning volume margins.« less

Single-cell-precision microplasma-induced cancer cell apoptosis.

PubMed

Tan, Xiao; Zhao, Shasha; Lei, Qian; Lu, Xinpei; He, Guangyuan; Ostrikov, Kostya

2014-01-01

The issue of single-cell control has recently attracted enormous interest. However, in spite of the presently achievable intracellular-level physiological probing through bio-photonics, nano-probe-based, and some other techniques, the issue of inducing selective, single-cell-precision apoptosis, without affecting neighbouring cells remains essentially open. Here we resolve this issue and report on the effective single-cell-precision cancer cell treatment using the reactive chemistry of the localized corona-type plasma discharge around a needle-like electrode with the spot size ∼1 µm. When the electrode is positioned with the micrometer precision against a selected cell, a focused and highly-localized micro-plasma discharge induces apoptosis in the selected individual HepG2 and HeLa cancer cells only, without affecting any surrounding cells, even in small cell clusters. This is confirmed by the real-time monitoring of the morphological and structural changes at the cellular and cell nucleus levels after the plasma exposure.

Localization of an Underwater Control Network Based on Quasi-Stable Adjustment.

PubMed

Zhao, Jianhu; Chen, Xinhua; Zhang, Hongmei; Feng, Jie

2018-03-23

There exists a common problem in the localization of underwater control networks that the precision of the absolute coordinates of known points obtained by marine absolute measurement is poor, and it seriously affects the precision of the whole network in traditional constraint adjustment. Therefore, considering that the precision of underwater baselines is good, we use it to carry out quasi-stable adjustment to amend known points before constraint adjustment so that the points fit the network shape better. In addition, we add unconstrained adjustment for quality control of underwater baselines, the observations of quasi-stable adjustment and constrained adjustment, to eliminate the unqualified baselines and improve the results' accuracy of the two adjustments. Finally, the modified method is applied to a practical LBL (Long Baseline) experiment and obtains a mean point location precision of 0.08 m, which improves by 38% compared with the traditional method.

Localization of an Underwater Control Network Based on Quasi-Stable Adjustment

PubMed Central

Chen, Xinhua; Zhang, Hongmei; Feng, Jie

2018-01-01

There exists a common problem in the localization of underwater control networks that the precision of the absolute coordinates of known points obtained by marine absolute measurement is poor, and it seriously affects the precision of the whole network in traditional constraint adjustment. Therefore, considering that the precision of underwater baselines is good, we use it to carry out quasi-stable adjustment to amend known points before constraint adjustment so that the points fit the network shape better. In addition, we add unconstrained adjustment for quality control of underwater baselines, the observations of quasi-stable adjustment and constrained adjustment, to eliminate the unqualified baselines and improve the results’ accuracy of the two adjustments. Finally, the modified method is applied to a practical LBL (Long Baseline) experiment and obtains a mean point location precision of 0.08 m, which improves by 38% compared with the traditional method. PMID:29570627

Organic electronics for high-resolution electrocorticography of the human brain.

PubMed

Khodagholy, Dion; Gelinas, Jennifer N; Zhao, Zifang; Yeh, Malcolm; Long, Michael; Greenlee, Jeremy D; Doyle, Werner; Devinsky, Orrin; Buzsáki, György

2016-11-01

Localizing neuronal patterns that generate pathological brain signals may assist with tissue resection and intervention strategies in patients with neurological diseases. Precise localization requires high spatiotemporal recording from populations of neurons while minimizing invasiveness and adverse events. We describe a large-scale, high-density, organic material-based, conformable neural interface device ("NeuroGrid") capable of simultaneously recording local field potentials (LFPs) and action potentials from the cortical surface. We demonstrate the feasibility and safety of intraoperative recording with NeuroGrids in anesthetized and awake subjects. Highly localized and propagating physiological and pathological LFP patterns were recorded, and correlated neural firing provided evidence about their local generation. Application of NeuroGrids to brain disorders, such as epilepsy, may improve diagnostic precision and therapeutic outcomes while reducing complications associated with invasive electrodes conventionally used to acquire high-resolution and spiking data.

Solution of Thermoelectricity Problems Energy Method

NASA Astrophysics Data System (ADS)

Niyazbek, Muheyat; Nogaybaeva, M. O.; Talp, Kuenssaule; Kudaikulov, A. A.

2018-06-01

On the basis of the fundamental laws of conservation of energy in conjunction with local quadratic spline functions was developed a universal computing algorithm, a method and associated software, which allows to investigate the Thermophysical insulated rod, with limited length, influenced by local heat flow, heat transfer and temperature

The role of heat shock protein 70 (Hsp70) in radiation-induced immunomodulation.

PubMed

Multhoff, Gabriele; Pockley, Alan G; Schmid, Thomas E; Schilling, Daniela

2015-11-28

Despite enormous progress in radiation technologies (high precision image-guided irradiation, proton irradiation, heavy ion irradiation) and radiotherapeutic concepts (hypofractionated irradiation schemes), the clinical outcome of radiotherapy in locally advanced and metastasized tumors and in hypoxic tumors which are radiation-resistant remains unsatisfactory. Given their key influence on a number of biological and immunological parameters, this article considers the influence of irradiation-induced stress proteins on radiation-induced immunomodulation. Depending on its location, the major stress-inducible Heat shock protein 70 (Hsp70) has been found to fulfill multiple roles. On the one hand, increased intracellular Hsp70 levels have been found to play a key role in the recovery from stress such as radio(chemo)therapy, and on the other hand extracellular Hsp70 proteins are potent stimulators of the innate immune system and mediators of anti-tumor immunity. Furthermore, if loaded with tumor-derived peptides, members of the Heat Shock Protein 70 (HSP70) and 90 (HSP90) families can stimulate the adaptive immune system via antigen cross-presentation. An irradiation-induced enhancement of the selective expression of a membrane form of Hsp70 on the surface of tumor cells which can act as a recognition structure for activated NK cells might have significant clinical relevance, in that the outcome of irradiation therapy for advanced tumors could be improved by combining it with cell-based and other immunotherapies that target this membrane form of Hsp70. Copyright © 2015 The Authors. Published by Elsevier Ireland Ltd.. All rights reserved.

Evaluating County-Level Heat Vulnerability and Social Inequity in the United States through Climate and Socioeconomic Indices

NASA Astrophysics Data System (ADS)

Gannon, C.

2016-12-01

Climate change will have many impacts on human health, perhaps most directly through extreme heat. High temperature and humidity combinations inhibit the body's ability to cool through physiological responses such as sweating. In conjunction with extended periods of extreme heat and shifted seasonality, these conditions are particularly dangerous. Current research and literature can be used to show where dangerous heat and humidity conditions are likely to be most prevalent, or where populations vulnerable to heat stress reside. To provide a better assessment of overall heat vulnerability, however, many complex factors, such as relative changes in temperature patterns or local socioeconomic conditions, must also be considered. Here, we utilize a multivariate approach to establish county-level risk scores by combining the most relevant indicators for heat vulnerability with climate model projections of wet bulb globe temperature, a metric useful for understanding how the human body will respond to conditions of high heat and humidity. We present our findings as an ESRI ArcOnline Story Map with data aggregated at the county-level in the continental United States. This format allows users to access maps showing each county's score in four categories related to heat vulnerability: heat and humidity hazards, population vulnerability, medical access, and physical infrastructure. A final map showcases a composite heat vulnerability score for each county, with comparisons to state and national averages. Our tool, part of the White House's Climate Data Initiative, is presented as a series of maps with a normalized scoring system to provide clear and easy access to the indicators most relevant to evaluating heat vulnerability at a local level. Ultimately, this readily available tool with general indices helps community decision makers communicate heat vulnerability and identify which resilience factors are most critical to improving local resilience.

Boiling Heat Transfer Measurements on Highly Conductive Surfaces Using Microscale Heater and Temperature Arrays

NASA Technical Reports Server (NTRS)

Kim, J.; Bae, S. W.; Whitten, M. W.; Mullen, J. D.; Quine, R. W.; Kalkur, T. S.

1999-01-01

Two systems have been developed to study boiling heat transfer on the microscale. The first system utilizes a 32 x 32 array of diodes to measure the local temperature fluctuations during boiling on a silicon wafer heated from below. The second system utilizes an array of 96 microscale heaters each maintained at constant surface temperature using electronic feedback loops. The power required to keep each heater at constant temperature is measured, enabling the local heat transfer coefficient to be determined. Both of these systems as well as some preliminary results are discussed.

Physical characterization of polyethylene glycols by thermal analytical technique and the effect of humidity and molecular weight.

PubMed

Majumdar, R; Alexander, K S; Riga, A T

2010-05-01

Polyethylene glycols (PEGs) are well known as excipients in tablet dosage formulations. PEGs are generally known to be inert and have very few interactions with other components in the solid dosage forms. However, the physical nature of PEGs and how they affect the disintegration of tablets is not very well understood for the different molecular weights of PEGs. The knowledge of the effect of molecular weight of PEGs on their physical properties and the effect of humidity on the physical properties of PEGs are important parameters for the choice of a PEG to be acceptable as an excipient in pharmaceutical formulations. This study was done to determine the precision of the DSC physical properties for a wide range of PEGs with varying molecular weights from 194 to 23000 daltons. Nine different molecular weights of PEGs were examined in a DSC controlled Heat-Cool-Heat-Cool-Heat (HCHCH) cycle and the observed reproducible values of melting temperature, heat of fusion, crystallization temperature and the heat of crystallization were compared with values obtained from the literature and the observed percent crystallinity was again cross-checked by X-ray Diffraction (XRD) studies. The comparison values indicated acceptable precision. This study was also done to check the effect of humidity on the DSC physical properties for the entire range of PEGs. The results indicated that humidity probably has a higher effect on the physical properties of the low molecular weight PEGs as compared to the high molecular weight PEGs.

Precision of EM Simulation Based Wireless Location Estimation in Multi-Sensor Capsule Endoscopy

PubMed Central

Ye, Yunxing; Aisha, Ain-Ul; Swar, Pranay; Pahlavan, Kaveh

2018-01-01

In this paper, we compute and examine two-way localization limits for an RF endoscopy pill as it passes through an individuals gastrointestinal (GI) tract. We obtain finite-difference time-domain and finite element method-based simulation results position assessment employing time of arrival (TOA). By means of a 3-D human body representation from a full-wave simulation software and lognormal models for TOA propagation from implant organs to body surface, we calculate bounds on location estimators in three digestive organs: stomach, small intestine, and large intestine. We present an investigation of the causes influencing localization precision, consisting of a range of organ properties; peripheral sensor array arrangements, number of pills in cooperation, and the random variations in transmit power of sensor nodes. We also perform a localization precision investigation for the situation where the transmission signal of the antenna is arbitrary with a known probability distribution. The computational solver outcome shows that the number of receiver antennas on the exterior of the body has higher impact on the precision of the location than the amount of capsules in collaboration within the GI region. The large intestine is influenced the most by the transmitter power probability distribution. PMID:29651364

Precision of EM Simulation Based Wireless Location Estimation in Multi-Sensor Capsule Endoscopy.

PubMed

Khan, Umair; Ye, Yunxing; Aisha, Ain-Ul; Swar, Pranay; Pahlavan, Kaveh

2018-01-01

In this paper, we compute and examine two-way localization limits for an RF endoscopy pill as it passes through an individuals gastrointestinal (GI) tract. We obtain finite-difference time-domain and finite element method-based simulation results position assessment employing time of arrival (TOA). By means of a 3-D human body representation from a full-wave simulation software and lognormal models for TOA propagation from implant organs to body surface, we calculate bounds on location estimators in three digestive organs: stomach, small intestine, and large intestine. We present an investigation of the causes influencing localization precision, consisting of a range of organ properties; peripheral sensor array arrangements, number of pills in cooperation, and the random variations in transmit power of sensor nodes. We also perform a localization precision investigation for the situation where the transmission signal of the antenna is arbitrary with a known probability distribution. The computational solver outcome shows that the number of receiver antennas on the exterior of the body has higher impact on the precision of the location than the amount of capsules in collaboration within the GI region. The large intestine is influenced the most by the transmitter power probability distribution.

Controlling heat and particle currents in nanodevices by quantum observation

NASA Astrophysics Data System (ADS)

Biele, Robert; Rodríguez-Rosario, César A.; Frauenheim, Thomas; Rubio, Angel

2017-07-01

We demonstrate that in a standard thermo-electric nanodevice the current and heat flows are not only dictated by the temperature and potential gradient, but also by the external action of a local quantum observer that controls the coherence of the device. Depending on how and where the observation takes place, the direction of heat and particle currents can be independently controlled. In fact, we show that the current and heat flow in a quantum material can go against the natural temperature and voltage gradients. Dynamical quantum observation offers new possibilities for the control of quantum transport far beyond classical thermal reservoirs. Through the concept of local projections, we illustrate how we can create and directionality control the injection of currents (electronic and heat) in nanodevices. This scheme provides novel strategies to construct quantum devices with application in thermoelectrics, spintronic injection, phononics, and sensing among others. In particular, highly efficient and selective spin injection might be achieved by local spin projection techniques.

PRECISION MANAGEMENT OF LOCALIZED PROSTATE CANCER

PubMed Central

VanderWeele, David J.; Turkbey, Baris; Sowalsky, Adam G.

2017-01-01

Introduction The vast majority of men who are diagnosed with prostate cancer die of other causes, highlighting the importance of determining which patient has a risk of death from prostate cancer. Precision management of prostate cancer patients includes distinguishing which men have potentially lethal disease and employing strategies for determining which treatment modality appropriately balances the desire to achieve a durable response while preventing unnecessary overtreatment. Areas covered In this review, we highlight precision approaches to risk assessment and a context for the precision-guided application of definitive therapy. We focus on three dilemmas relevant to the diagnosis of localized prostate cancer: screening, the decision to treat, and postoperative management. Expert commentary In the last five years, numerous precision tools have emerged with potential benefit to the patient. However, to achieve optimal outcome, the decision to employ one or more of these tests must be considered in the context of prevailing conventional factors. Moreover, performance and interpretation of a molecular or imaging precision test remains practitioner-dependent. The next five years will witness increased marriage of molecular and imaging biomarkers for improved multi-modal diagnosis and discrimination of disease that is aggressive versus truly indolent. PMID:28133630

Assessing complexity of skin blood flow oscillations in response to locally applied heating and pressure in rats: Implications for pressure ulcer risk

NASA Astrophysics Data System (ADS)

Liao, Fuyuan; O'Brien, William D.; Jan, Yih-Kuen

2013-10-01

The objective of this study was to investigate the effects of local heating on the complexity of skin blood flow oscillations (BFO) under prolonged surface pressure in rats. Eleven Sprague-Dawley rats were studied: 7 rats underwent surface pressure with local heating (△t=10 °C) and 4 rats underwent pressure without heating. A pressure of 700 mmHg was applied to the right trochanter area of rats for 3 h. Skin blood flow was measured using laser Doppler flowmetry. The loading period was divided into nonoverlapping 30 min epochs. For each epoch, multifractal detrended fluctuation analysis (MDFA) was utilized to compute DFA coefficients and complexity of endothelial related metabolic, neurogenic, and myogenic frequencies of BFO. The results showed that under surface pressure, local heating led to a significant decrease in DFA coefficients of myogenic frequency during the initial epoch of loading period, a sustained decrease in complexity of myogenic frequency, and a significantly higher degree of complexity of metabolic frequency during the later phase of loading period. Surrogate tests showed that the reduction in complexity of myogenic frequency was associated with a loss of nonlinearity whereas increased complexity of metabolic frequency was associated with enhanced nonlinearity. Our results indicate that increased metabolic activity and decreased myogenic response due to local heating manifest themselves not only in magnitudes of metabolic and myogenic frequencies but also in their structural complexity. This study demonstrates the feasibility of using complexity analysis of BFO to monitor the ischemic status of weight-bearing skin and risk of pressure ulcers.

Method of forming capsules containing a precise amount of material

DOEpatents

Grossman, Mark W.; George, William A.; Maya, Jakob

1986-01-01

A method of forming a sealed capsule containing a submilligram quantity of mercury or the like, the capsule being constructed from a hollow glass tube, by placing a globule or droplet of the mercury in the tube. The tube is then evacuated and sealed and is subsequently heated so as to vaporize the mercury and fill the tube therewith. The tube is then separated into separate sealed capsules by heating spaced locations along the tube with a coiled heating wire means to cause collapse spaced locations therealong and thus enable separation of the tube into said capsules.

Method of forming capsules containing a precise amount of material

DOEpatents

Grossman, M.W.; George, W.A.; Maya, J.

1986-06-24

A method of forming a sealed capsule containing a submilligram quantity of mercury or the like, the capsule being constructed from a hollow glass tube, by placing a globule or droplet of the mercury in the tube. The tube is then evacuated and sealed and is subsequently heated so as to vaporize the mercury and fill the tube therewith. The tube is then separated into separate sealed capsules by heating spaced locations along the tube with a coiled heating wire means to cause collapse spaced locations there along and thus enable separation of the tube into said capsules. 7 figs.

Inexpensive Flow Microcalorimeter For Measuring Heat Production of Attached and Sedimentary Aquatic Microorganisms

PubMed Central

Lock, Maurice A.; Ford, Tim E.

1983-01-01

A relatively inexpensive flow microcalorimeter is described which is capable of detecting heat outputs as low as 3 μW (precision, ±2%). Its use is illustrated on river epilithon (0.8 to 6.8 μW cm−2), river sand (9.8 μW cm−3), and marine sand (15.3 μW cm−3); however, it could be used to detect the heat output from any biotic material over which a flow of water can be passed, provided that such an action would not be disruptive to chemical and biological equilibria. PMID:16346368

A Low-cost Environmental Control System for Precise Radial Velocity Spectrometers

NASA Astrophysics Data System (ADS)

Sliski, David H.; Blake, Cullen H.; Halverson, Samuel

2017-12-01

We present an environmental control system (ECS) designed to achieve milliKelvin (mK) level temperature stability for small-scale astronomical instruments. This ECS is inexpensive and is primarily built from commercially available components. The primary application for our ECS is the high-precision Doppler spectrometer MINERVA-Red, where the thermal variations of the optical components within the instrument represent a major source of systematic error. We demonstrate ±2 mK temperature stability within a 0.5 m3 thermal enclosure using resistive heaters in conjunction with a commercially available PID controller and off-the-shelf thermal sensors. The enclosure is maintained above ambient temperature, enabling rapid cooling through heat dissipation into the surrounding environment. We demonstrate peak-to-valley (PV) temperature stability of better than 5 mK within the MINERVA-Red vacuum chamber, which is located inside the thermal enclosure, despite large temperature swings in the ambient laboratory environment. During periods of stable laboratory conditions, the PV variations within the vacuum chamber are less than 3 mK. This temperature stability is comparable to the best stability demonstrated for Doppler spectrometers currently achieving m s-1 radial velocity precision. We discuss the challenges of using commercially available thermoelectrically cooled CCD cameras in a temperature-stabilized environment, and demonstrate that the effects of variable heat output from the CCD camera body can be mitigated using PID-controlled chilled water systems. The ECS presented here could potentially provide the stable operating environment required for future compact “astrophotonic” precise radial velocity (PRV) spectrometers to achieve high Doppler measurement precision with a modest budget.

Thermal Dose is Related to Duration of Local Control in Canine Sarcomas Undergoing Thermoradiotherapy

PubMed Central

Thrall, Donald E.; LaRue, Susan M.; Yu, Daohai; Samulski, Thaddeus; Sanders, Linda; Case, Beth; Rosner, Gary; Azuma, Chieko; Poulson, Jeannie; Pruitt, Amy F.; Stanley, Wilma; Hauck, Marlene L.; Williams, Laurel; Hess, Paul; Dewhirst, Mark W.

2009-01-01

Purpose To test that prospective delivery of higher thermal dose is associated with longer tumor control duration. Experimental Design 122 dogs with a heatable soft tissue sarcoma were randomized to receive a low (2–5 CEM43°CT90) or high (20–50 CEM43°CT90) thermal dose in combination with radiotherapy. Most dogs (90%) received 4–6 hyperthermia treatments over 5 weeks. Results In the primary analysis, median (95% CI) duration of local control in the low dose group was 1.2 (0.7–2.1) years versus 1.9 (1.4–3.2) years in the high dose group (logrank p=0.28). The probability (95% CI) of tumor control at one year in the low vs. high dose groups was 0.57 (0.43–0.70) vs. 0.74 (0.62–0.86), respectively. Using multivariable procedure, thermal dose group (p=0.023), total duration of heating (p=0.008), tumor volume (p=0.041) and tumor grade (p=0.027) were significantly related to duration of local tumor control. When correcting for volume, grade and duration of heating, dogs in the low dose group were 2.3 times as likely to experience local failure. Conclusions Thermal dose is directly related to local control duration in irradiated canine sarcomas. Longer heating being associated with shorter local tumor control was unexpected. However, the effect of thermal dose on tumor control was stronger than for heating duration. The heating duration effect is possibly mediated through deleterious effects on tumor oxygenation. These results are the first to show the value of prospectively controlled thermal dose in achieving local tumor control with thermoradiotherapy, and they establish a paradigm for prescribing thermoradiotherapy and writing a thermal prescription. PMID:16033838

Thin-Film Thermocouple Technology Demonstrated for Reliable Heat Transfer Measurements

NASA Technical Reports Server (NTRS)

1996-01-01

Exploratory work is in progress to apply thin-film thermocouples to localized heat transfer measurements on turbine engine vanes and blades. The emerging thin-film thermocouple technology shows great potential to improve the accuracy of local heat transfer measurements. To verify and master the experimental methodology of thin-film thermocouples, the NASA Lewis Research Center conducted a proof-of-concept experiment in a controlled environment before applying the thin-film sensors to turbine tests.

Resonance localization and poloidal electric field due to cyclo- tron wave heating in tokamak plasmas

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hsu, J.Y.; Chan, V.S.; Harvey, R.W.

1984-08-06

The perpendicular heating in cyclotron waves tends to pile up the resonant particles toward the low magnetic field side with their banana tips localized to the resonant surface. A poloidal electric field with an E x B drift comparable to the ion vertical drift in a toroidal magnetic field may result. With the assumption of anomalous electron and neoclassical ion transport, density variations due to wave heating are discussed.

Nonionic Cellulose Ethers as Potential Drug Delivery Systems for Periodontal Anesthesia.

PubMed

Scherlund; Brodin; Malmsten

2000-09-15

Nonionic cellulose ethers displaying a lower consolute temperature, or cloud-point, close to body temperature were investigated as potential carrier systems for the delivery of local anesthetic agents to the periodontal pocket. The interaction between the polymers, i.e., ethyl(hydroxyethyl)cellulose (EHEC) and hydrophobically modified EHEC (HM-EHEC), and ionic surfactants was determined in the absence and in the presence of the local anesthetic agents lidocaine and prilocaine. The cloud-point and rheology data indicate interactions between the polymer and both anionic and cationic surfactants. More precisely, a number of ionic surfactants were found to result in an increase in cloud-point at higher surfactant concentrations, a surfactant-concentration-dependent thickening, and a temperature-induced gelation upon heating. Upon addition of the local anesthetic agents lidocaine and prilocaine in their uncharged form to EHEC and HM-EHEC, in the absence of surfactants, only minor interaction with the polymer could be inferred. However, these substances were found to affect the polymer-surfactant interaction. In particular, the drug release rate in vitro as well as the stability and temperature-dependent viscosity were followed for an EHEC/SDS system and EHEC/myristoylcholine bromide system upon addition of lidocaine and prilocaine. The data indicate a possibility of formulating a local anesthetic drug delivery system suitable for administration into the periodontal pocket where at least small amounts of active ingredients can be incorporated into the system without severely affecting the gelation behavior. The results found for the cationic myristoylcholine bromide system are particularly interesting for the application in focus here since this surfactant is antibacterial and readily biodegradable. Copyright 2000 Academic Press.

Timing and structure of the penultimate deglaciation in north China constrained by a precisely dated stalagmite record

NASA Astrophysics Data System (ADS)

Duan, W.; Cheng, H.; Tan, M.; Li, X.; Edwards, R. L.

2017-12-01

The timing and structure of the penultimate deglaciation (Termination II, T-II) is still controversial due to the lack of precise-date and high-resolution paleoclimate documents. This study firstly presents high-precision stalagmite δ18O data encompassing T-II from north China, near the northern limit of the East Asian summer monsoon (EASM), an area sensitive to climate change. An obvious 2200-year long 18O-depleted excursion was identified within T-II, 1500 years later than in south China, mostly indicating it's a hitherto unidentified interstadial event, but the possibility of a local signal linked to karst hydrologic changes cannot be excluded. The sharpest T-II transition occurred at 129.20 ka BP (BP=before AD 1950), consistent with other EASM records but 3000 years later than mid-high-latitudinal cave records in Europe and North America. The different ages between them are attributed to that the original ice sheet melting during T-II did not inhibit the overturning in the Nordic Seas, leaving the heat transport to western Europe unaffected. Furthermore, the rise in EASM after the main T-II transition was interrupted by a significant "pause" in our record, whereas only expressed as a "slowdown" in south Chinese caves, further confirming the higher sensitivity of climate in north China. Compared with the last deglaciation (T-I), this climate pause could be considered as a Younger Dryas (YD)-type event that was shifted into the early stage of the last interglacial period, though its intensity and duration were not as strong as the YD during T-I. Key words: North China stalagmite record Timing and structure Termination II

Medical instrument based on a heat pipe for local cavity hypothermia

NASA Astrophysics Data System (ADS)

Vasil'Ev, L. L.; Zhuraviyov, A. S.; Molodkin, F. F.; Khrolenok, V. V.; Zhdanov, V. L.; Vasil'Ev, V. L.; Adamov, S. I.; Tyurin, A. A.

1996-05-01

The design and results of tests of an instrument based on a heat pipe for local cavity hypothermia are presented. The instrument is a part of a device for noninvasive nonmedical treatment of inflammatory diseases of the organs of the small pelvis, pathologies of alimentary canal, etc.

24 CFR 35.140 - Prohibited methods of paint removal.

Code of Federal Regulations, 2011 CFR

2011-04-01

... air (HEPA) local exhaust control. (c) Abrasive blasting or sandblasting without HEPA local exhaust control. (d) Heat guns operating above 1100 degrees Fahrenheit or charring the paint. (e) Dry sanding or dry scraping, except dry scraping in conjunction with heat guns or within 1.0 ft. (0.30 m.) of...

24 CFR 35.140 - Prohibited methods of paint removal.

Code of Federal Regulations, 2013 CFR

2013-04-01

... air (HEPA) local exhaust control. (c) Abrasive blasting or sandblasting without HEPA local exhaust control. (d) Heat guns operating above 1100 degrees Fahrenheit or charring the paint. (e) Dry sanding or dry scraping, except dry scraping in conjunction with heat guns or within 1.0 ft. (0.30 m.) of...

24 CFR 35.140 - Prohibited methods of paint removal.

Code of Federal Regulations, 2012 CFR

2012-04-01

... air (HEPA) local exhaust control. (c) Abrasive blasting or sandblasting without HEPA local exhaust control. (d) Heat guns operating above 1100 degrees Fahrenheit or charring the paint. (e) Dry sanding or dry scraping, except dry scraping in conjunction with heat guns or within 1.0 ft. (0.30 m.) of...

24 CFR 35.140 - Prohibited methods of paint removal.

Code of Federal Regulations, 2014 CFR

2014-04-01

... air (HEPA) local exhaust control. (c) Abrasive blasting or sandblasting without HEPA local exhaust control. (d) Heat guns operating above 1100 degrees Fahrenheit or charring the paint. (e) Dry sanding or dry scraping, except dry scraping in conjunction with heat guns or within 1.0 ft. (0.30 m.) of...

Effect of Reynolds number, turbulence level and periodic wake flow on heat transfer on low pressure turbine blades.

PubMed

Suslov, D; Schulz, A; Wittig, S

2001-05-01

The development of effective cooling methods is of major importance for the design of new gas turbines blades. The conception of optimal cooling schemes requires a detailed knowledge of the heat transfer processes on the blade's surfaces. The thermal load of turbine blades is predominantly determined by convective heat transfer which is described by the local heat transfer coefficient. Heat transfer is closely related to the boundary layer development along the blade surface and hence depends on various flow conditions and geometrical parameters. Particularly Reynolds number, pressures gradient and turbulence level have great impact on the boundary layer development and the according heat transfer. Therefore, in the present study, the influence of Reynolds number, turbulence intensity, and periodic unsteady inflow on the local heat transfer of a typical low pressure turbine airfoil is experimentally examined in a plane cascade.

Micro axial tomography: A miniaturized, versatile stage device to overcome resolution anisotropy in fluorescence light microscopy

NASA Astrophysics Data System (ADS)

Staier, Florian; Eipel, Heinz; Matula, Petr; Evsikov, Alexei V.; Kozubek, Michal; Cremer, Christoph; Hausmann, Michael

2011-09-01

With the development of novel fluorescence techniques, high resolution light microscopy has become a challenging technique for investigations of the three-dimensional (3D) micro-cosmos in cells and sub-cellular components. So far, all fluorescence microscopes applied for 3D imaging in biosciences show a spatially anisotropic point spread function resulting in an anisotropic optical resolution or point localization precision. To overcome this shortcoming, micro axial tomography was suggested which allows object tilting on the microscopic stage and leads to an improvement in localization precision and spatial resolution. Here, we present a miniaturized device which can be implemented in a motor driven microscope stage. The footprint of this device corresponds to a standard microscope slide. A special glass fiber can manually be adjusted in the object space of the microscope lens. A stepwise fiber rotation can be controlled by a miniaturized stepping motor incorporated into the device. By means of a special mounting device, test particles were fixed onto glass fibers, optically localized with high precision, and automatically rotated to obtain views from different perspective angles under which distances of corresponding pairs of objects were determined. From these angle dependent distance values, the real 3D distance was calculated with a precision in the ten nanometer range (corresponding here to an optical resolution of 10-30 nm) using standard microscopic equipment. As a proof of concept, the spindle apparatus of a mature mouse oocyte was imaged during metaphase II meiotic arrest under different perspectives. Only very few images registered under different rotation angles are sufficient for full 3D reconstruction. The results indicate the principal advantage of the micro axial tomography approach for many microscopic setups therein and also those of improved resolutions as obtained by high precision localization determination.

One-wire thermocouple

NASA Technical Reports Server (NTRS)

Goodrich, W. D.; Staimach, C. J.

1977-01-01

Nickel alloy/constantan device accurately measures surface temperature at precise locations. Device is moderate in cost and simplifies fabrication of highly-instrumented seamless-surface heat-transfer models. Device also applies to metal surfaces if constantan wire has insulative coat.

Increased Air Velocity Reduces Thermal and Cardiovascular Strain in Young and Older Males during Humid Exertional Heat Stress.

PubMed

Wright Beatty, Heather E; Hardcastle, Stephen G; Boulay, Pierre; Flouris, Andreas D; Kenny, Glen P

2015-01-01

Older adults have been reported to have a lower evaporative heat loss capacity than younger adults during exercise when full sweat evaporation is permitted. However, it is unclear how conditions of restricted evaporative and convective heat loss (i.e., high humidity, clothing insulation) alter heat stress. to the purpose of this study was to examine the heat stress responses of young and older males during and following exercise in a warm/humid environment under two different levels of air velocity. Ten young (YOUNG: 24±2 yr) and 10 older (OLDER: 59±3 yr) males, matched for body surface area performed 4×15-min cycling bouts (15-min rest) at a fixed rate of heat production (400 W) in warm/humid conditions (35°C, 60% relative humidity) under 0.5 (Low) and 3.0 (High) m·s(-1) air velocity while wearing work coveralls. Rectal (Tre) and mean skin (MTsk) temperatures, heart rate (HR), local sweat rate, % max skin blood flow (SkBF) (recovery only), and blood pressure (recovery only) were measured. High air velocity reduced core and skin temperatures (p < 0.05) equally in YOUNG and OLDER males (p > 0.05) but was more effective in reducing cardiovascular strain (absolute and % max HR; p < 0.05) in YOUNG males (p < 0.05). Greater increases in local dry heat loss responses (% max SkBF and cutaneous vascular conductance) were detected across time in OLDER than YOUNG males in both conditions (p < 0.05). Local dry heat loss responses and cardiovascular strain were attenuated during the High condition in YOUNG compared to OLDER (p < 0.05). High air velocity reduced the number of males surpassing the 38.0°C Tre threshold from 90% (Low) to 50% (High). Despite age-related local heat loss differences, YOUNG and OLDER males had similar levels of heat stress during intermittent exercise in warm and humid conditions while wearing work coveralls. Increased air velocity was effective in reducing heat stress equally, and cardiovascular strain to a greater extent, in YOUNG and OLDER males, and may be useful for mitigating heat stress in all workers.

Fabrication of precision optics using an imbedded reference surface

DOEpatents

Folta, James A.; Spiller, Eberhard

2005-02-01

The figure of a substrate is very precisely measured and a figured-correcting layer is provided on the substrate. The thickness of the figure-correcting layer is locally measured and compared to the first measurement. The local measurement of the figure-correcting layer is accomplished through a variety of methods, including interferometry and fluorescence or ultrasound measurements. Adjustments in the thickness of the figure-correcting layer are made until the top of the figure-correcting layer matches a desired figure specification.

ANALYZING NUMERICAL ERRORS IN DOMAIN HEAT TRANSPORT MODELS USING THE CVBEM.

USGS Publications Warehouse

Hromadka, T.V.; ,

1985-01-01

Besides providing an exact solution for steady-state heat conduction processes (Laplace Poisson equations), the CVBEM (complex variable boundary element method) can be used for the numerical error analysis of domain model solutions. For problems where soil water phase change latent heat effects dominate the thermal regime, heat transport can be approximately modeled as a time-stepped steady-state condition in the thawed and frozen regions, respectively. The CVBEM provides an exact solution of the two-dimensional steady-state heat transport problem, and also provides the error in matching the prescribed boundary conditions by the development of a modeling error distribution or an approximative boundary generation. This error evaluation can be used to develop highly accurate CVBEM models of the heat transport process, and the resulting model can be used as a test case for evaluating the precision of domain models based on finite elements or finite differences.

Spatial Manipulation of Heat Flow by Surface Boundaries at the Nanoscale

NASA Astrophysics Data System (ADS)

Malhotra, Abhinav; Maldovan, Martin

The precise manipulation of phonon transport properties is central to controlling thermal transport in semiconductor nanostructures. The physical understanding, prediction, and control of thermal phonon heat spectra and thermal conductivity accumulation functions - which establish the proportion of heat transported by phonons with different frequencies and mean-free-paths - has attracted significant attention in recent years. In this talk, we advance the possibilities of manipulating heat by spatially modulating thermal transport in nanostructures. We show that phonon scattering at interfaces impacts the most preferred physical pathway used by heat energy flow in thermal transport in nanostructures. The role of introducing boundaries with different surface conditions on resultant thermal flux is presented and methodologies to enhance these spatial modulations are discussed. This talk aims to advance the fundamental understanding on the nature of heat transport at nanoscale with potential applications in multiple research areas ranging from energy materials to optoelectronics.

1.9 K Heat Inleak and Resistive Heating Measurements on Lhc Cryomagnets

NASA Astrophysics Data System (ADS)

Ferlin, G.; Claudet, S.; Tavian, L.; Wagner, U.

2010-04-01

The superconducting magnets of the Large Hadron Collider (LHC) distributed over eight sectors of 3.3-km long are cooled at 1.9 K in pressurized superfluid helium. During the commissioning campaign of the sectors in 2008, cold standby periods at nominal operating temperature have allowed to measure the overall static heat inleaks reaching the magnet cold masses at 1.9 K by enthalpy balance in steady-state operation. In addition, during electrical powering of the different magnet circuits, helium II calorimetry based on precision thermometry has been implemented to assess with an accuracy of 100 mW/m the additional heat loads due to resistive heating and to detect possible abnormal heat dissipation during powering. This paper describes the method applied to perform these measurements, compares the results with the expected specified values and discusses the impact of the measured values on cryo-plant tuning and operational margins.

Feasibility of using interstitial ultrasound for intradiscal thermal therapy: a study in human cadaver lumbar discs

NASA Astrophysics Data System (ADS)

Nau, William H.; Diederich, Chris J.; Shu, Richard

2005-06-01

Application of heat in the spine using resistive wire heating devices is currently being used clinically for minimally invasive treatment of discogenic low back pain. In this study, interstitial ultrasound was evaluated for the potential to heat intradiscal tissue more precisely by directing energy towards the posterior annular wall while avoiding vertebral bodies. Two single-element directional applicator design configurations were tested: a 1.5 mm OD direct-coupled (DC) applicator which can be implanted directly within the disc, and a catheter-cooled (CC) applicator which is inserted in a 2.4 mm OD catheter with integrated water cooling and implanted within the disc. The transducers were sectored to produce 90° spatial heating patterns for directional control. Both applicator configurations were evaluated in four human cadaver lumbar disc motion segments. Two heating protocols were employed in this study in which the temperature measured 5 mm away from the applicator was controlled to either T = 52 °C, or T > 70 °C for the treatment period. These temperatures (thermal doses) are representative of those required for thermal necrosis of in-growing nociceptor nerve fibres and disc cellularity alone, or with coagulation and restructuring of annular collagen in the high-temperature case. Steady-state temperature maps, and thermal doses (t43) were used to assess the thermal treatments. Results from these studies demonstrated the capability of controlling temperature distributions within selected regions of the disc and annular wall using interstitial ultrasound, with minimal vertebral end-plate heating. While directional heating was demonstrated with both applicator designs, the CC configuration had greater directional heating capabilities and offered better temperature control than the DC configuration, particularly during the high-temperature protocol. Further, ultrasound energy was capable of penetrating within the highly attenuating disc tissue to produce more extensive radial thermal penetration, lower maximum intradiscal temperature, and shorter treatment times than can be achieved with current clinical intradiscal heating technology. Thus, interstitial ultrasound offers potential as a more precise and faster heating modality for the clinical management of low back pain.

The calculating study of the moisture transfer influence at the temperature field in a porous wet medium with internal heat sources

NASA Astrophysics Data System (ADS)

Kuzevanov, V. S.; Garyaev, A. B.; Zakozhurnikova, G. S.; Zakozhurnikov, S. S.

2017-11-01

A porous wet medium with solid and gaseous components, with distributed or localized heat sources was considered. The regimes of temperature changes at the heating at various initial material moisture were studied. Mathematical model was developed applied to the investigated wet porous multicomponent medium with internal heat sources, taking into account the transfer of the heat by heat conductivity with variable thermal parameters and porosity, heat transfer by radiation, chemical reactions, drying and moistening of solids, heat and mass transfer of volatile products of chemical reactions by flows filtration, transfer of moisture. The algorithm of numerical calculation and the computer program that implements the proposed mathematical model, allowing to study the dynamics of warming up at a local or distributed heat release, in particular the impact of the transfer of moisture in the medium on the temperature field were created. Graphs of temperature change were obtained at different points of the graphics with different initial moisture. Conclusions about the possible control of the regimes of heating a solid porous body by the initial moisture distribution were made.

Turbulent Heat-Transfer Coefficients in the Vicinity of Surface Protuberances

NASA Technical Reports Server (NTRS)

Wisniewski, Richard J.

1958-01-01

Local turbulent heating rates were obtained in the vicinity of surface protuberances mounted on the cylinder section of a cone cylinder model at a Mach number of 3.12. Data were obtained at Reynolds number per foot of 4.5 and 6 million for an unswept cylinder, a 45 deg swept cylinder, a 45 deg elbow, and several 90 deg elbows. The unswept cylinder and the 90 deg elbows increased the local turbulent heating rates in the vicinity of the surface protuberances. The data of the 45 deg swept cylinder and the 45 deg elbow resulted in heating rates lower than those observed without surface protuberances. In general, sweeping a surface protuberance resulted in heating rates comparable or lower than those measured without surface protuberances.

A numerical model for boiling heat transfer coefficient of zeotropic mixtures

NASA Astrophysics Data System (ADS)

Barraza Vicencio, Rodrigo; Caviedes Aedo, Eduardo

2017-12-01

Zeotropic mixtures never have the same liquid and vapor composition in the liquid-vapor equilibrium. Also, the bubble and the dew point are separated; this gap is called glide temperature (Tglide). Those characteristics have made these mixtures suitable for cryogenics Joule-Thomson (JT) refrigeration cycles. Zeotropic mixtures as working fluid in JT cycles improve their performance in an order of magnitude. Optimization of JT cycles have earned substantial importance for cryogenics applications (e.g, gas liquefaction, cryosurgery probes, cooling of infrared sensors, cryopreservation, and biomedical samples). Heat exchangers design on those cycles is a critical point; consequently, heat transfer coefficient and pressure drop of two-phase zeotropic mixtures are relevant. In this work, it will be applied a methodology in order to calculate the local convective heat transfer coefficients based on the law of the wall approach for turbulent flows. The flow and heat transfer characteristics of zeotropic mixtures in a heated horizontal tube are investigated numerically. The temperature profile and heat transfer coefficient for zeotropic mixtures of different bulk compositions are analysed. The numerical model has been developed and locally applied in a fully developed, constant temperature wall, and two-phase annular flow in a duct. Numerical results have been obtained using this model taking into account continuity, momentum, and energy equations. Local heat transfer coefficient results are compared with available experimental data published by Barraza et al. (2016), and they have shown good agreement.

AIR EMISSIONS FROM RESIDENTIAL HEATING: THE WOOD HEATING OPTION PUT INTO ENVIRONMENTAL PERSPECTIVE

EPA Science Inventory

The paper compares the national scale (rather than local) air quality impacts of the various residential space heating options. Specifically, it compares the relative contribution of the space heating options to fine particulate emissions, greenhouse gas emissions, and acid preci...

Convex optimization of MRI exposure for mitigation of RF-heating from active medical implants.

PubMed

Córcoles, Juan; Zastrow, Earl; Kuster, Niels

2015-09-21

Local RF-heating of elongated medical implants during magnetic resonance imaging (MRI) may pose a significant health risk to patients. The actual patient risk depends on various parameters including RF magnetic field strength and frequency, MR coil design, patient's anatomy, posture, and imaging position, implant location, RF coupling efficiency of the implant, and the bio-physiological responses associated with the induced local heating. We present three constrained convex optimization strategies that incorporate the implant's RF-heating characteristics, for the reduction of local heating of medical implants during MRI. The study emphasizes the complementary performances of the different formulations. The analysis demonstrates that RF-induced heating of elongated metallic medical implants can be carefully controlled and balanced against MRI quality. A reduction of heating of up to 25 dB can be achieved at the cost of reduced uniformity in the magnitude of the B(1)(+) field of less than 5%. The current formulations incorporate a priori knowledge of clinically-specific parameters, which is assumed to be available. Before these techniques can be applied practically in the broader clinical context, further investigations are needed to determine whether reduced access to a priori knowledge regarding, e.g. the patient's anatomy, implant routing, RF-transmitter, and RF-implant coupling, can be accepted within reasonable levels of uncertainty.

Glove thermal insulation: local heat transfer measures and relevance.

PubMed

Sari, Hayet; Gartner, Maurice; Hoeft, Alain; Candas, Victor

2004-09-01

When exposed to cold, the hands need to be protected against heat loss not only in order to reduce thermal discomfort, but also to keep their efficiency. Although gloves are usually the most common protection, their thermal insulation is generally unknown. The aim of this study was to measure the heat losses from a gloved hand with a special interest in local variations. Using a calorimetric hand placed in a cold box, several types of gloves were tested. The results indicated that depending on the glove and on the area covered the heat loss reduction may vary from almost 60% to 90%. When the least efficient pair of gloves was excluded, heat exchange coefficients varied from 1.8 to 4.8 W/m2 per degrees C for the palm and from 4.2 to 6.2 W/m2 per degrees C for the back of the hand. The three medium fingers seemed to be equally treated, with a heat exchange coefficient variation of 6.3-9.0 W/m2 per degrees C. The thumb and the little finger, which require better insulation, exhibited higher local heat transfer coefficients of 8.3-12.7 W/m2 per degrees C. Some practical aspects are evoked.

Strategies to reduce the harmful effects of extreme heat events: a four-city study.

PubMed

White-Newsome, Jalonne L; McCormick, Sabrina; Sampson, Natalie; Buxton, Miatta A; O'Neill, Marie S; Gronlund, Carina J; Catalano, Linda; Conlon, Kathryn C; Parker, Edith A

2014-02-13

Extreme heat events (EHEs) are becoming more intense, more frequent and longer lasting in the 21st century. These events can disproportionately impact the health of low-income, minority, and urban populations. To better understand heat-related intervention strategies used by four U.S. cities, we conducted 73 semi-structured interviews with government and non-governmental organization leaders representing public health, general social services, emergency management, meteorology, and the environmental planning sectors in Detroit, MI; New York City, NY; Philadelphia, PA and Phoenix, AZ-cities selected for their diverse demographics, climates, and climate adaptation strategies. We identified activities these leaders used to reduce the harmful effects of heat for residents in their city, as well as the obstacles they faced and the approaches they used to evaluate these efforts. Local leaders provided a description of how local context (e.g., climate, governance and city structure) impacted heat preparedness. Despite the differences among study cities, political will and resource access were critical to driving heat-health related programming. Upon completion of our interviews, we convened leaders in each city to discuss these findings and their ongoing efforts through day-long workshops. Our findings and the recommendations that emerged from these workshops could inform other local or national efforts towards preventing heat-related morbidity and mortality.

Convex optimization of MRI exposure for mitigation of RF-heating from active medical implants

NASA Astrophysics Data System (ADS)

Córcoles, Juan; Zastrow, Earl; Kuster, Niels

2015-09-01

Local RF-heating of elongated medical implants during magnetic resonance imaging (MRI) may pose a significant health risk to patients. The actual patient risk depends on various parameters including RF magnetic field strength and frequency, MR coil design, patient’s anatomy, posture, and imaging position, implant location, RF coupling efficiency of the implant, and the bio-physiological responses associated with the induced local heating. We present three constrained convex optimization strategies that incorporate the implant’s RF-heating characteristics, for the reduction of local heating of medical implants during MRI. The study emphasizes the complementary performances of the different formulations. The analysis demonstrates that RF-induced heating of elongated metallic medical implants can be carefully controlled and balanced against MRI quality. A reduction of heating of up to 25 dB can be achieved at the cost of reduced uniformity in the magnitude of the B1+ field of less than 5%. The current formulations incorporate a priori knowledge of clinically-specific parameters, which is assumed to be available. Before these techniques can be applied practically in the broader clinical context, further investigations are needed to determine whether reduced access to a priori knowledge regarding, e.g. the patient’s anatomy, implant routing, RF-transmitter, and RF-implant coupling, can be accepted within reasonable levels of uncertainty.

Strategies to Reduce the Harmful Effects of Extreme Heat Events: A Four-City Study

PubMed Central

White-Newsome, Jalonne L.; McCormick, Sabrina; Sampson, Natalie; Buxton, Miatta A.; O’Neill, Marie S.; Gronlund, Carina J.; Catalano, Linda; Conlon, Kathryn C.; Parker, Edith A.

2014-01-01

Extreme heat events (EHEs) are becoming more intense, more frequent and longer lasting in the 21st century. These events can disproportionately impact the health of low-income, minority, and urban populations. To better understand heat-related intervention strategies used by four U.S. cities, we conducted 73 semi-structured interviews with government and non-governmental organization leaders representing public health, general social services, emergency management, meteorology, and the environmental planning sectors in Detroit, MI; New York City, NY; Philadelphia, PA and Phoenix, AZ—cities selected for their diverse demographics, climates, and climate adaptation strategies. We identified activities these leaders used to reduce the harmful effects of heat for residents in their city, as well as the obstacles they faced and the approaches they used to evaluate these efforts. Local leaders provided a description of how local context (e.g., climate, governance and city structure) impacted heat preparedness. Despite the differences among study cities, political will and resource access were critical to driving heat-health related programming. Upon completion of our interviews, we convened leaders in each city to discuss these findings and their ongoing efforts through day-long workshops. Our findings and the recommendations that emerged from these workshops could inform other local or national efforts towards preventing heat-related morbidity and mortality. PMID:24531122

Application of the predicted heat strain model in development of localized, threshold-based heat stress management guidelines for the construction industry.

PubMed

Rowlinson, Steve; Jia, Yunyan Andrea

2014-04-01

Existing heat stress risk management guidelines recommended by international standards are not practical for the construction industry which needs site supervision staff to make instant managerial decisions to mitigate heat risks. The ability of the predicted heat strain (PHS) model [ISO 7933 (2004). Ergonomics of the thermal environment analytical determination and interpretation of heat stress using calculation of the predicted heat strain. Geneva: International Standard Organisation] to predict maximum allowable exposure time (D lim) has now enabled development of localized, action-triggering and threshold-based guidelines for implementation by lay frontline staff on construction sites. This article presents a protocol for development of two heat stress management tools by applying the PHS model to its full potential. One of the tools is developed to facilitate managerial decisions on an optimized work-rest regimen for paced work. The other tool is developed to enable workers' self-regulation during self-paced work.

Numerical simulation of heat transfer in metal foams

NASA Astrophysics Data System (ADS)

Gangapatnam, Priyatham; Kurian, Renju; Venkateshan, S. P.

2018-02-01

This paper reports a numerical study of forced convection heat transfer in high porosity aluminum foams. Numerical modeling is done considering both local thermal equilibrium and non local thermal equilibrium conditions in ANSYS-Fluent. The results of the numerical model were validated with experimental results, where air was forced through aluminum foams in a vertical duct at different heat fluxes and velocities. It is observed that while the LTE model highly under predicts the heat transfer in these foams, LTNE model predicts the Nusselt number accurately. The novelty of this study is that once hydrodynamic experiments are conducted the permeability and porosity values obtained experimentally can be used to numerically simulate heat transfer in metal foams. The simulation of heat transfer in foams is further extended to find the effect of foam thickness on heat transfer in metal foams. The numerical results indicate that though larger foam thicknesses resulted in higher heat transfer coefficient, this effect weakens with thickness and is negligible in thick foams.

Photothermal lesions in soft tissue induced by optical fiber microheaters.

PubMed

Pimentel-Domínguez, Reinher; Moreno-Álvarez, Paola; Hautefeuille, Mathieu; Chavarría, Anahí; Hernández-Cordero, Juan

2016-04-01

Photothermal therapy has shown to be a promising technique for local treatment of tumors. However, the main challenge for this technique is the availability of localized heat sources to minimize thermal damage in the surrounding healthy tissue. In this work, we demonstrate the use of optical fiber microheaters for inducing thermal lesions in soft tissue. The proposed devices incorporate carbon nanotubes or gold nanolayers on the tips of optical fibers for enhanced photothermal effects and heating of ex vivo biological tissues. We report preliminary results of small size photothermal lesions induced on mice liver tissues. The morphology of the resulting lesions shows that optical fiber microheaters may render useful for delivering highly localized heat for photothermal therapy.

Mechanically-reattachable liquid-cooled cooling apparatus

DOEpatents

Arney, Susanne; Cheng, Jen-Hau; Kolodner, Paul R; Kota-Venkata, Krishna-Murty; Scofield, William; Salamon, Todd R; Simon, Maria E

2013-09-24

An apparatus comprising a rack having a row of shelves, each shelf supporting an electronics circuit board, each one of the circuit boards being manually removable from the shelve supporting the one of the circuit boards and having a local heat source thereon. The apparatus also comprises a cooler attached to the rack and being able to circulate a cooling fluid around a channel forming a closed loop. The apparatus further comprises a plurality of heat conduits, each heat conduit being located over a corresponding one of the circuit boards and forming a path to transport heat from the local heat source of the corresponding one of the circuit boards to the cooler. Each heat conduit is configured to be manually detachable from the cooler or the circuit board, without breaking a circulation pathway of the fluid through the cooler.

Evaluation Methodology between Globalization and Localization Features Approaches for Skin Cancer Lesions Classification

NASA Astrophysics Data System (ADS)

Ahmed, H. M.; Al-azawi, R. J.; Abdulhameed, A. A.

2018-05-01

Huge efforts have been put in the developing of diagnostic methods to skin cancer disease. In this paper, two different approaches have been addressed for detection the skin cancer in dermoscopy images. The first approach uses a global method that uses global features for classifying skin lesions, whereas the second approach uses a local method that uses local features for classifying skin lesions. The aim of this paper is selecting the best approach for skin lesion classification. The dataset has been used in this paper consist of 200 dermoscopy images from Pedro Hispano Hospital (PH2). The achieved results are; sensitivity about 96%, specificity about 100%, precision about 100%, and accuracy about 97% for globalization approach while, sensitivity about 100%, specificity about 100%, precision about 100%, and accuracy about 100% for Localization Approach, these results showed that the localization approach achieved acceptable accuracy and better than globalization approach for skin cancer lesions classification.

Overview of recent and current research on the TCV tokamak

NASA Astrophysics Data System (ADS)

S. Codathe TCV Team

2013-10-01

Through a diverse research programme, the Tokamak à Configuration Variable (TCV) addresses physics issues and develops tools for ITER and for the longer term goals of nuclear fusion, relying especially on its extreme plasma shaping and electron cyclotron resonance heating (ECRH) launching flexibility and preparing for an ECRH and NBI power upgrade. Localized edge heating was unexpectedly found to decrease the period and relative energy loss of edge localized modes (ELMs). Successful ELM pacing has been demonstrated by following individual ELM detection with an ECRH power cut before turning the power back up to trigger the next ELM, the duration of the cut determining the ELM period. Negative triangularity was also seen to reduce the ELM energy release. H-mode studies have focused on the L-H threshold dependence on the main ion species and on the divertor leg length. Both L- and H-modes have been explored in the snowflake configuration with emphasis on edge measurements, revealing that the heat flux to the strike points on the secondary separatrix increases as the X-points approach each other, well before they coalesce. In L-mode, a systematic scan of the auxiliary power deposition profile, with no effect on confinement, has ruled it out as the cause of confinement degradation. An ECRH power absorption observer based on transmitted stray radiation was validated for eventual polarization control. A new profile control methodology was introduced, relying on real-time modelling to supplement diagnostic information; the RAPTOR current transport code in particular has been employed for joint control of the internal inductance and central temperature. An internal inductance controller using the ohmic transformer has also been demonstrated. Fundamental investigations of neoclassical tearing mode (NTM) seed island formation by sawtooth crashes and of NTM destabilization in the absence of a sawtooth trigger were carried out. Both stabilizing and destabilizing agents (electron cyclotron current drive on or inside the q = 1 surface, respectively) were used to pace sawtooth oscillations, permitting precise control of their period. Locking of the sawtooth period to a pre-defined ECRH modulation period was also demonstrated. Sawtooth control has permitted nearly failsafe NTM prevention when combined with backup NTM stabilization by ECRH.

Ultrashort pulse laser machining of metals and alloys

DOEpatents

Perry, Michael D.; Stuart, Brent C.

2003-09-16

The invention consists of a method for high precision machining (cutting, drilling, sculpting) of metals and alloys. By using pulses of a duration in the range of 10 femtoseconds to 100 picoseconds, extremely precise machining can be achieved with essentially no heat or shock affected zone. Because the pulses are so short, there is negligible thermal conduction beyond the region removed resulting in negligible thermal stress or shock to the material beyond approximately 0.1-1 micron (dependent upon the particular material) from the laser machined surface. Due to the short duration, the high intensity (>10.sup.12 W/cm.sup.2) associated with the interaction converts the material directly from the solid-state into an ionized plasma. Hydrodynamic expansion of the plasma eliminates the need for any ancillary techniques to remove material and produces extremely high quality machined surfaces with negligible redeposition either within the kerf or on the surface. Since there is negligible heating beyond the depth of material removed, the composition of the remaining material is unaffected by the laser machining process. This enables high precision machining of alloys and even pure metals with no change in grain structure.

Replication of linkage to quantitative trait loci: variation in location and magnitude of the lod score.

PubMed

Hsueh, W C; Göring, H H; Blangero, J; Mitchell, B D

2001-01-01

Replication of linkage signals from independent samples is considered an important step toward verifying the significance of linkage signals in studies of complex traits. The purpose of this empirical investigation was to examine the variability in the precision of localizing a quantitative trait locus (QTL) by analyzing multiple replicates of a simulated data set with the use of variance components-based methods. Specifically, we evaluated across replicates the variation in both the magnitude and the location of the peak lod scores. We analyzed QTLs whose effects accounted for 10-37% of the phenotypic variance in the quantitative traits. Our analyses revealed that the precision of QTL localization was directly related to the magnitude of the QTL effect. For a QTL with effect accounting for > 20% of total phenotypic variation, > 90% of the linkage peaks fall within 10 cM from the true gene location. We found no evidence that, for a given magnitude of the lod score, the presence of interaction influenced the precision of QTL localization.

Precision and accuracy in smFRET based structural studies—A benchmark study of the Fast-Nano-Positioning System

NASA Astrophysics Data System (ADS)

Nagy, Julia; Eilert, Tobias; Michaelis, Jens

2018-03-01

Modern hybrid structural analysis methods have opened new possibilities to analyze and resolve flexible protein complexes where conventional crystallographic methods have reached their limits. Here, the Fast-Nano-Positioning System (Fast-NPS), a Bayesian parameter estimation-based analysis method and software, is an interesting method since it allows for the localization of unknown fluorescent dye molecules attached to macromolecular complexes based on single-molecule Förster resonance energy transfer (smFRET) measurements. However, the precision, accuracy, and reliability of structural models derived from results based on such complex calculation schemes are oftentimes difficult to evaluate. Therefore, we present two proof-of-principle benchmark studies where we use smFRET data to localize supposedly unknown positions on a DNA as well as on a protein-nucleic acid complex. Since we use complexes where structural information is available, we can compare Fast-NPS localization to the existing structural data. In particular, we compare different dye models and discuss how both accuracy and precision can be optimized.

Photoacoustic-based sO2 estimation through excised bovine prostate tissue with interstitial light delivery.

PubMed

Mitcham, Trevor; Taghavi, Houra; Long, James; Wood, Cayla; Fuentes, David; Stefan, Wolfgang; Ward, John; Bouchard, Richard

2017-09-01

Photoacoustic (PA) imaging is capable of probing blood oxygen saturation (sO 2 ), which has been shown to correlate with tissue hypoxia, a promising cancer biomarker. However, wavelength-dependent local fluence changes can compromise sO 2 estimation accuracy in tissue. This work investigates using PA imaging with interstitial irradiation and local fluence correction to assess precision and accuracy of sO 2 estimation of blood samples through ex vivo bovine prostate tissue ranging from 14% to 100% sO 2 . Study results for bovine blood samples at distances up to 20 mm from the irradiation source show that local fluence correction improved average sO 2 estimation error from 16.8% to 3.2% and maintained an average precision of 2.3% when compared to matched CO-oximeter sO 2 measurements. This work demonstrates the potential for future clinical translation of using fluence-corrected and interstitially driven PA imaging to accurately and precisely assess sO 2 at depth in tissue with high resolution.

Local time dependence of turbulent magnetic fields in Saturn's magnetodisc

NASA Astrophysics Data System (ADS)

Kaminker, V.; Delamere, P. A.; Ng, C. S.; Dennis, T.; Otto, A.; Ma, X.

2017-04-01

Net plasma transport in magnetodiscs around giant planets is outward. Observations of plasma temperature have shown that the expanding plasma is heating nonadiabatically during this process. Turbulence has been suggested as a source of heating. However, the mechanism and distribution of magnetic fluctuations in giant magnetospheres are poorly understood. In this study we attempt to quantify the radial and local time dependence of fluctuating magnetic field signatures that are suggestive of turbulence, quantifying the fluctuations in terms of a plasma heating rate density. In addition, the inferred heating rate density is correlated with magnetic field configurations that include azimuthal bend forward/back and magnitude of the equatorial normal component of magnetic field relative to the dipole. We find a significant local time dependence in magnetic fluctuations that is consistent with flux transport triggered in the subsolar and dusk sectors due to magnetodisc reconnection.

The collapse of the local, Spitzer-Haerm formulation and a global-local generalization for heat flow in an inhomogeneous, fully ionized plasma

NASA Technical Reports Server (NTRS)

Scudder, J. D.; Olbert, S.

1983-01-01

The breakdown of the classical (CBES) field aligned transport relations for electrons in an inhomogeneous, fully ionized plasma as a mathematical issue of radius of convergence is addressed, the finite Knudsen number conditions when CBES results are accurate is presented and a global-local (GL) way to describe the results of Coulomb physics moderated conduction that is more nearly appropriate for astrophysical plasmas are defined. This paper shows the relationship to and points of departure of the present work from the CBES approach. The CBES heat law in current use is shown to be an especially restrictive special case of the new, more general GL result. A preliminary evaluation of the dimensionless heat function, using analytic formulas, shows that the dimensionless heat function profiles versus density of the type necessary for a conduction supported high speed solar wind appear possible.

Apparatus for precise regulation and chilling of water temperatures in laboratory studies

USGS Publications Warehouse

Burger, C.; ,

1991-01-01

Laboratory simulation of water temperature regimes that occur in subarctic rivers through winter necessitates the ability to maintain near-freezing conditions. A heat-exchangeing apparatus is described that provided a convenient means of simulating the range of temperatures (0.5-12 degrees C) that incubating eggs of salmon (Oncorhynchus spp.) typically experience in south-central Alaska watersheds. The system was reliable, easily maintained precise temperatures at our coldest test levels, and was used over several years with few mechanical complications.

Shuttle Technology for Earth Laboratories

NASA Technical Reports Server (NTRS)

1987-01-01

Pyran System represents a major advancement in control of pyrolysis, the technology of subjecting organic material to selected temperatures to break them down into their component parts, and that the system offers capabilities unavailable. Pyran System is designed for rapid automated analysis of the composition of organic matter. It is capable of heating samples to 1,130 degrees fahrenheit with infrared heat at a precisely controlled atmosphere. In order to do this with the degree of control and repeatability desired, the developers of the Pyran system decided they would need a special type of material to insulate the heating chambers. They adopted the shuttle tiles for the difficult insulating job. The tiles provide superior insulating characteristics needed, and they can be readily cut and formed to fit the heating chambers.

Tower reactors for bioconversion of lignocellulosic material

DOEpatents

Nguyen, Q.A.

1998-03-31

An apparatus is disclosed for enzymatic hydrolysis and fermentation of pretreated lignocellulosic material. The apparatus consists of a tower bioreactor which has mixers to achieve intermittent mixing of the material. Precise mixing of the material is important for effective heat and mass transfer requirements without damaging or denaturing the enzymes or fermenting microorganisms. The pretreated material, generally in the form of a slurry, is pumped through the bioreactor, either upwards or downwards, and is mixed periodically as it passes through the mixing zones where the mixers are located. For a thin slurry, alternate mixing can be achieved by a pumping loop which also serves as a heat transfer device. Additional heat transfer takes place through the reactor heat transfer jackets. 5 figs.

Tower reactors for bioconversion of lignocellulosic material

DOEpatents

Nguyen, Q.A.

1999-03-30

An apparatus is described for enzymatic hydrolysis and fermentation of pretreated lignocellulosic material, in the form of a tower bioreactor, having mixers to achieve intermittent mixing of the material. Precise mixing of the material is important for effective heat and mass transfer requirements without damaging or denaturing the enzymes or fermenting microorganisms. The pretreated material, generally in the form of a slurry, is pumped through the bioreactor, either upwards or downwards, and is mixed periodically as it passes through the mixing zones where the mixers are located. For a thin slurry, alternate mixing can be achieved by a pumping loop which also serves as a heat transfer device. Additional heat transfer takes place through the reactor heat transfer jackets. 5 figs.

Local probing of thermal energy transfer and conversion processes in VO2 nanostructures

NASA Astrophysics Data System (ADS)

Menges, Fabian

Nanostructures of strongly correlated materials, such as metal-insulator transition (MIT) oxides, enable unusual coupling of charge and heat transport. Hence, they provide an interesting pathway to the development of non-linear thermal devices for active heat flux control. Here, we will report the characterization of local thermal non-equilibrium processes in vanadium dioxide (VO2) thin films and single-crystalline nanobeams. Using a scanning thermal microscope and calorimetric MEMS platforms, we studied the MIT triggered by electrical currents, electrical fields, near-field thermal radiation and thermal conduction. Based on out recently introduced scanning probe thermometry method, which enables direct imaging of local Joule and Peltier effects, we quantified self-heating processes in VO2 memristors using the tip of a resistively heated scanning probe both as local sensor and nanoscopic heat source. Finally, we will report on recent approaches to build radiative thermal switches and oscillators using VO2 nanostructures. We quantified variations of near-field radiative thermal transport between silicon dioxide and VO2 down to nanoscopic gap sizes, and will discuss its implications for the development of phonon polariton based radiative thermal devices. Funding of the Swiss Federal Office of Energy under Grant Agreement No. SI/501093-01 is gratefully acknowledged.

Heat input and accumulation for ultrashort pulse processing with high average power

NASA Astrophysics Data System (ADS)

Finger, Johannes; Bornschlegel, Benedikt; Reininghaus, Martin; Dohrn, Andreas; Nießen, Markus; Gillner, Arnold; Poprawe, Reinhart

2018-05-01

Materials processing using ultrashort pulsed laser radiation with pulse durations <10 ps is known to enable very precise processing with negligible thermal load. However, even for the application of picosecond and femtosecond laser radiation, not the full amount of the absorbed energy is converted into ablation products and a distinct fraction of the absorbed energy remains as residual heat in the processed workpiece. For low average power and power densities, this heat is usually not relevant for the processing results and dissipates into the workpiece. In contrast, when higher average powers and repetition rates are applied to increase the throughput and upscale ultrashort pulse processing, this heat input becomes relevant and significantly affects the achieved processing results. In this paper, we outline the relevance of heat input for ultrashort pulse processing, starting with the heat input of a single ultrashort laser pulse. Heat accumulation during ultrashort pulse processing with high repetition rate is discussed as well as heat accumulation for materials processing using pulse bursts. In addition, the relevance of heat accumulation with multiple scanning passes and processing with multiple laser spots is shown.

High-temperature ceramic heat exchanger element for a solar thermal receiver

NASA Technical Reports Server (NTRS)

Strumpf, H. J.; Kotchick, D. M.; Coombs, M. G.

1982-01-01

A study has been completed on the development of a high-temperature ceramic heat exchanger element to be integrated into a solar reciver producing heated air. A number of conceptual designs were developed for heat exchanger elements of differing configuration. These were evaluated with respect to thermal performance, pressure drop, structural integrity, and fabricability. The final design selection identified a finned ceramic shell as the most favorable concept. The ceramic shell is surrounded by a larger metallic shell. The flanges of the two shells are sealed to provide a leak-tight pressure vessel. The ceramic shell is fabricated by an innovative combination of slip casting the receiver walls and precision casting the heat transfer finned plates. The fins are bonded to the shell during firing. Fabrication of a one-half scale demonstrator ceramic receiver has been completed.

Counterintuitive Constraints on Chaos Formation Set by Heat Flux through Europa's Ocean

NASA Astrophysics Data System (ADS)

Goodman, J. C.

2013-12-01

Models for the formation of disruptive chaos features on the icy surface of Europa fall into two broad categories: either chaos is formed when basal heating causes localized melting and thinning of the ice shell, or basal heating drives diapiric convection within the ice shell. We argue that in both of these cases, heating of the ice shell from below does not lead to chaos formation at the location of heating. If chaos is formed when a localized oceanic heat source, such as a hydrothermal plume, "melts through" the ice crust, we must consider what happens to the melted liquid. If Europa's ocean is salty, the melt will form a buoyant pool inside the melted cavity, leading to a stable interface between cold fresh meltwater and warm salty seawater. This stable interface acts like an ablative heat shield, protecting the ice from further damage. Some heat can be transferred across the stable layer by double diffusion, but this transfer is very inefficient. We calculate that local ocean heating cannot be balanced by local flux through the stable layer: instead, the warm ocean water must spread laterally until it is delivering heat to the ice base on a regional or global scale (a heating zone hundreds or thousands of km across, for conservative parameters.) If chaos is formed by diapiric solid-state convection within the ice shell, many investigators have assumed that diapirism and chaos should be most prevalent where the basal heat flux is strongest. We argue that this is not the case. In Rayleigh-Benard convection, increasing the heat flux will make convection more vigorous --- if and only if the convecting layer thickness does not change. We argue that increased basal heat flux will thin the ice shell, reducing its Rayleigh number and making convection less likely, not more. This insight allows us to reverse the logic of recent discussions of the relationship between ocean circulation and chaos (for instance, Soderlund et al, 2013 LPSC). We argue that global oceanic heat transport is governed by geostrophic quasi-two-dimensional convection, which delivers less heat to the tropics and more to the poles. By the argument above, this implies that the ice layer should be thicker in the tropics, and thus more prone to diapiric convection: thus, chaos should be more common there. Recent mapping efforts by other investigators have shown that this does appear to be the case.

β-adrenergic blockade does not impair the skin blood flow sensitivity to local heating in burned and non-burned skin under neutral and hot environments in children

PubMed Central

Rivas, Eric; McEntire, Serina J.; Herndon, David N.; Mlcak, Ronald P.; Suman, Oscar E.

2017-01-01

Objective Tested the hypothesis that propranolol, a drug given to burn patients to reduce hypermetabolism/cardiac stress, may inhibit heat dissipation by changing the sensitivity of skin blood flow (SkBF) to local heating under neutral and hot conditions. Methods In a randomized double-blind study, a placebo was given to 8 burned children while propranolol was given to 13 burned children with similar characteristics (mean ± SD: 11.9±3y, 147±20cm, 45±23kg, 56±12% TBSA). Non-burned children (n=13, 11.4±3y, 152±15cm, 52±13kg) served as healthy controls. A progressive local heating protocol characterized SkBF responses in burned and unburned skin and non-burned control skin under the two environmental conditions (23°C and 34°C) via laser-Doppler flowmetry. Results Resting SkBF was greater in burned and unburned skin compared to the non-burned control (main effect: skin, P<0.0001; 57±32 burned; 38±36 unburned vs 9±8 control %SkBFmax). No difference was found for maximal SkBF capacity to local heating between groups. Additionally, dose response curves for the sensitivity of SkBF to local heating were not different among burned or unburned skin, and non-burned control skin (EC50, P>0.05) under either condition. Conclusion Therapeutic propranolol does not negatively affect SkBF under neutral or hot environmental conditions and further compromise temperature regulation in burned children. PMID:28071840

β-Adrenergic blockade does not impair the skin blood flow sensitivity to local heating in burned and nonburned skin under neutral and hot environments in children.

PubMed

Rivas, Eric; McEntire, Serina J; Herndon, David N; Mlcak, Ronald P; Suman, Oscar E

2017-05-01

We tested the hypothesis that propranolol, a drug given to burn patients to reduce hypermetabolism/cardiac stress, may inhibit heat dissipation by changing the sensitivity of skin blood flow (SkBF) to local heating under neutral and hot conditions. In a randomized double-blind study, a placebo was given to eight burned children, while propranolol was given to 13 burned children with similar characteristics (mean±SD: 11.9±3 years, 147±20 cm, 45±23 kg, 56±12% Total body surface area burned). Nonburned children (n=13, 11.4±3 years, 152±15 cm, 52±13 kg) served as healthy controls. A progressive local heating protocol characterized SkBF responses in burned and unburned skin and nonburned control skin under the two environmental conditions (23 and 34°C) via laser Doppler flowmetry. Resting SkBF was greater in burned and unburned skin compared to the nonburned control (main effect: skin, P<.0001; 57±32 burned; 38±36 unburned vs 9±8 control %SkBF max ). No difference was found for maximal SkBF capacity to local heating between groups. Additionally, dose-response curves for the sensitivity of SkBF to local heating were not different among burned or unburned skin, and nonburned control skin (EC 50 , P>.05) under either condition. Therapeutic propranolol does not negatively affect SkBF under neutral or hot environmental conditions and further compromise temperature regulation in burned children. © 2017 John Wiley & Sons Ltd.

Heat Treat Shop in the Technical Services Building

NASA Image and Video Library

1948-01-21

A technician prepares a metal component for a high-temperature bake in the Heat Treatment Shop at the National Advisory Committee for Aeronautics (NACA) Lewis Flight Propulsion Laboratory. Fabrication Division under Dan White and John Dalgleish created almost all of the equipment and models used at the laboratory. The Technical Services Building, referred to as the Fab Shop, contained a number of specialized shops in the 1940s and 1950s. These included a Machine Shop, Sheet Metal Shop, Wood and Pattern Shop, Instrument Shop, Thermocouple Shop, Heat Treating Shop, Metallurgical Laboratory, and Fabrication Office. The Metallurgical Laboratory contained a control lab for the Heat Treating Shop and a service lab for the NACA Lewis research divisions. This metallurgical group performed tensile and impact tests on metals to determine their suitability for specific research or equipment. The Heat Treating Shop heated metal parts to optimize their physical properties and contained a Precision Castings Foundry to manufacture equipment made of heat resisting alloys.

Heat and mass transfer at gas-phase ignition of grinded coal layer by several metal particles heated to a high temperature

NASA Astrophysics Data System (ADS)

Glushkov, D. O.; Kuznetsov, G. V.; Strizhak, P. A.

2017-07-01

Characteristics of gas-phase ignition of grinded brown coal (brand 2B, Shive-Ovoos deposit in Mongolia) layer by single and several metal particles heated to a high temperature (above 1000 K) have been investigated numerically. The developed mathematical model of the process takes into account the heating and thermal decomposition of coal at the expense of the heat supplied from local heat sources, release of volatiles, formation and heating of gas mixture and its ignition. The conditions of the joint effect of several hot particles on the main characteristic of the process-ignition delay time are determined. The relation of the ignition zone position in the vicinity of local heat sources and the intensity of combustible gas mixture warming has been elucidated. It has been found that when the distance between neighboring particles exceeds 1.5 hot particle size, an analysis of characteristics and regularities of coal ignition by several local heat sources can be carried out within the framework of the model of "single metal particle / grinded coal / air". Besides, it has been shown with the use of this model that the increase in the hot particle height leads, along with the ignition delay time reduction, to a reduction of the source initial temperatures required for solid fuel ignition. At an imperfect thermal contact at the interface hot particle / grinded coal due to the natural porosity of the solid fuel structure, the intensity of ignition reduces due to a less significant effect of radiation in the area of pores on the heat transfer conditions compared to heat transfer by conduction in the near-surface coal layer without regard to its heterogeneous structure.

Amplified Thermionic Cooling Using Arrays of Nanowires

NASA Technical Reports Server (NTRS)

Yang, Eui-Hyeok; Choi, Daniel; Shcheglov, Kirill; Hishinuma, Yoshikazu

2007-01-01

A class of proposed thermionic cooling devices would incorporate precise arrays of metal nanowires as electron emitters. The proposed devices could be highly miniaturized, enabling removal of heat from locations, very close to electronic devices, that have previously been inaccessible for heat-removal purposes. The resulting enhancement of removal of heat would enable operation of the devices at higher power levels and higher clock speeds. Moreover, the mass, complexity, and bulk of electronic circuitry incorporating these highly miniaturized cooling devices could be considerably reduced, relative to otherwise equivalent circuitry cooled by conventional electromechanical, thermoelectric, and fluidic means. In thermionic cooling, one exploits the fact that because only the highest-energy electrons are thermionically emitted, collecting those electrons to prevent their return to the emitting electrode results in the net removal of heat from that electrode. Collection is effected by applying an appropriate positive bias potential to another electrode placed near the emitting electrode. The concept underlying the proposal is that the thermionic-emission current and, hence, the cooling effect attainable by use of an array of nanowires could be significantly greater than that attainable by use of a single emitting electrode or other electron- emitting surface. The wires in an array according to the proposal would protrude perpendicularly from a planar surface and their heights would be made uniform to within a sub-nanometer level of precision

Nanocalorimeter platform for in situ specific heat measurements and x-ray diffraction at low temperature

NASA Astrophysics Data System (ADS)

Willa, K.; Diao, Z.; Campanini, D.; Welp, U.; Divan, R.; Hudl, M.; Islam, Z.; Kwok, W.-K.; Rydh, A.

2017-12-01

Recent advances in electronics and nanofabrication have enabled membrane-based nanocalorimetry for measurements of the specific heat of microgram-sized samples. We have integrated a nanocalorimeter platform into a 4.5 T split-pair vertical-field magnet to allow for the simultaneous measurement of the specific heat and x-ray scattering in magnetic fields and at temperatures as low as 4 K. This multi-modal approach empowers researchers to directly correlate scattering experiments with insights from thermodynamic properties including structural, electronic, orbital, and magnetic phase transitions. The use of a nanocalorimeter sample platform enables numerous technical advantages: precise measurement and control of the sample temperature, quantification of beam heating effects, fast and precise positioning of the sample in the x-ray beam, and fast acquisition of x-ray scans over a wide temperature range without the need for time-consuming re-centering and re-alignment. Furthermore, on an YBa2Cu3O7-δ crystal and a copper foil, we demonstrate a novel approach to x-ray absorption spectroscopy by monitoring the change in sample temperature as a function of incident photon energy. Finally, we illustrate the new insights that can be gained from in situ structural and thermodynamic measurements by investigating the superheated state occurring at the first-order magneto-elastic phase transition of Fe2P, a material that is of interest for magnetocaloric applications.

Climate-driven variations in thermal forcing across a nearshore reef system during a marine heat wave and its potential impact on coral calcification

NASA Astrophysics Data System (ADS)

Falter, J.; Zhang, Z.; Lowe, R.; Foster, T.; McCulloch, M. T.

2016-02-01

We examined the oceanic and atmospheric forces driving seasonal and spatial variability in water temperature across backreef and lagoonal habitats at Coral Bay at Ningaloo Reef, Western Australia before, during, and after a historically unprecedented marine heat wave and resulting mass bleaching event in 2010-2011. Local deviations in the mean daily temperature of nearshore reef waters from offshore values were a linear function of the combined effect of net atmospheric heating and offshore wave height and period . While intra-annual variation in local heat exchange was driven mainly by seasonal changes in short-wave radiation; intra-annual variation in local cooling was driven mostly by changes in relative humidity (r2 = 0.60) and wind speed (r2 = 0.31) which exhibited no apparent seasonality. We demonstrate good agreement between nearshore reef temperatures modeled from offshore sea surface temperatures (SST), offshore wave forcing, and local atmospheric heat fluxes with observed temperatures using a simple linear model (r2 = 0.31 to 0.69, root-mean-square error = 0.4°C to 0.9°C). Using these modeled nearshore reef temperature records, we show that during the heat wave local thermal stresses across the reef reached as high as 18-34 °C-weeks and were being both intensified and accelerated by regional climate forcing when compared with offshore waters (12.6 °C-weeks max). Measurements of coral calcification made in Coral Bay following the bleaching event appear to lack any distinct seasonality; possibly due to the long-term effects of acute thermal stress. However, similarly minimal seasonality in calcification rates had also been observed in an Acropora-dominated community at Ningaloo years before the heat wave as well as more recently in coral from regions in WA that had avoided mass bleaching. These observations, in conjunction with observations that most of the bleached communities within Coral Bay had recovered their color within 3-6 months of the bleaching event, suggest that how reef building coral respond to a severe thermal stress event can be somewhat nuanced depending on the local and regional setting.

Urban Heat Islands and Their Mitigation vs. Local Impacts of Climate Change

NASA Astrophysics Data System (ADS)

Taha, H.

2007-12-01

Urban heat islands and their mitigation take on added significance, both negative and positive, when viewed from a climate-change perspective. In negative terms, urban heat islands can act as local exacerbating factors, or magnifying lenses, to the effects of regional and large-scale climate perturbations and change. They can locally impact meteorology, energy/electricity generation and use, thermal environment (comfort and heat waves), emissions of air pollutants, photochemistry, and air quality. In positive terms, on the other hand, mitigation of urban heat islands (via urban surface modifications and control of man-made heat, for example) can potentially have a beneficial effect of mitigating the local negative impacts of climate change. In addition, mitigation of urban heat islands can, in itself, contribute to preventing regional and global climate change, even if modestly, by helping reduce CO2 emissions from power plants and other sources as a result of decreased energy use for cooling (both direct and indirect) and reducing the rates of meteorology-dependent emissions of air pollutants. This presentation will highlight aspects and characteristics of heat islands, their mitigation, their modeling and quantification techniques, and recent advances in meso-urban modeling of California (funded by the California Energy Commission). In particular, the presentation will focus on results from quantitative, modeling-based analyses of the potential benefits of heat island mitigation in 1) reducing point- and area-source emissions of CO2, NOx, and VOC as a result of reduced cooling energy demand and ambient/surface temperatures, 2) reducing evaporative and fugitive hydrocarbon emissions as a result of lowered temperatures, 3) reducing biogenic hydrocarbon emissions from existing vegetative cover, 4) slowing the rates of tropospheric/ground-level ozone formation and/or accumulation in the urban boundary layer, and 5) helping improve air quality. Quantitative estimates of the above will be presented based on recent and earlier meteorological, energy, thermal environmental, emissions, and photochemical modeling studies for California and Texas.

Characterization and Prediction of Flow Behavior in High-Manganese Twinning Induced Plasticity Steels: Part II. Jerky Flow and Instantaneous Strain Rate

NASA Astrophysics Data System (ADS)

Saeed-Akbari, A.; Mishra, A. K.; Mayer, J.; Bleck, W.

2012-05-01

The jerky and smooth flow curves in high-manganese twinning induced plasticity (TWIP) steels were investigated by comparing Fe-Mn-C and Fe-Mn-Al-C systems. The pronounced serrations on the flow curves of Fe-Mn-C TWIP steel, produced during tensile testing at 300 K (27 °C) and 373 K (100 °C), were shown to be the result of localized high-temperature Portevin Le-Chatelier (PLC) bands moving across the gage length throughout the deformation. The speed of the PLC bands and their temperature effects were found to be strongly dependent on the applied strain rate, which was controlled by adjusting the cross-head speed of the tensile testing machine. The localized temperature-dependent stacking fault energy (SFE) variations resulting from the PLC effect and adiabatic heating were analyzed and compared for both slow and fast deformation rates. The instabilities in the measured logarithmic strain values caused by jerky flow could cause the local strain rate to deviate systematically from the targeted (applied) strain rate. These instabilities are better observed by calculating the instantaneous strain rate (ISR) values for each instant of deformation along the entire gage length. Finally, a new type of diagram was developed by plotting the true stress against the ISR values. From the diagram, the onset of different mechanisms, such as deformation twinning, nonpronounced, and pronounced serrations, could be marked precisely.

MSH1 Is a Plant Organellar DNA Binding and Thylakoid Protein under Precise Spatial Regulation to Alter Development

DOE PAGES

Virdi, Kamaldeep S.; Wamboldt, Yashitola; Kundariya, Hardik; ...

2015-11-14

As metabolic centers, plant organelles participate in maintenance, defense, and signaling. MSH1 is a plant-specific protein involved in organellar genome stability in mitochondria and plastids. Plastid depletion of MSH1 causes heritable, non-genetic changes in development and DNA methylation. We investigated the msh1 phenotype using hemi-complementation mutants and transgene-null segregants from RNAi suppression lines to sub-compartmentalize MSH1 effects. We show that MSH1 expression is spatially regulated, specifically localizing to plastids within the epidermis and vascular parenchyma. The protein binds DNA and localizes to plastid and mitochondrial nucleoids, but fractionation and protein–protein interactions data indicate that MSH1 also associates with the thylakoidmore » membrane. Plastid MSH1 depletion results in variegation, abiotic stress tolerance, variable growth rate, and delayed maturity. Depletion from mitochondria results in 7%–10% of plants altered in leaf morphology, heat tolerance, and mitochondrial genome stability. MSH1 does not localize within the nucleus directly, but plastid depletion produces non-genetic changes in flowering time, maturation, and growth rate that are heritable independent of MSH1. MSH1 depletion alters non-photoactive redox behavior in plastids and a sub-set of mitochondrially altered lines. Ectopic expression produces deleterious effects, underlining its strict expression control. Unraveling the complexity of the MSH1 effect offers insight into triggers of plant-specific, transgenerational adaptation behaviors.« less

Segmentation precision of abdominal anatomy for MRI-based radiotherapy

PubMed Central

Noel, Camille E.; Zhu, Fan; Lee, Andrew Y.; Yanle, Hu; Parikh, Parag J.

2014-01-01

The limited soft tissue visualization provided by computed tomography, the standard imaging modality for radiotherapy treatment planning and daily localization, has motivated studies on the use of magnetic resonance imaging (MRI) for better characterization of treatment sites, such as the prostate and head and neck. However, no studies have been conducted on MRI-based segmentation for the abdomen, a site that could greatly benefit from enhanced soft tissue targeting. We investigated the interobserver and intraobserver precision in segmentation of abdominal organs on MR images for treatment planning and localization. Manual segmentation of 8 abdominal organs was performed by 3 independent observers on MR images acquired from 14 healthy subjects. Observers repeated segmentation 4 separate times for each image set. Interobserver and intraobserver contouring precision was assessed by computing 3-dimensional overlap (Dice coefficient [DC]) and distance to agreement (Hausdorff distance [HD]) of segmented organs. The mean and standard deviation of intraobserver and interobserver DC and HD values were DCintraobserver = 0.89 ± 0.12, HDintraobserver = 3.6 mm ± 1.5, DCinterobserver = 0.89 ± 0.15, and HDinterobserver = 3.2 mm ± 1.4. Overall, metrics indicated good interobserver/intraobserver precision (mean DC > 0.7, mean HD < 4 mm). Results suggest that MRI offers good segmentation precision for abdominal sites. These findings support the utility of MRI for abdominal planning and localization, as emerging MRI technologies, techniques, and onboard imaging devices are beginning to enable MRI-based radiotherapy. PMID:24726701

Segmentation precision of abdominal anatomy for MRI-based radiotherapy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Noel, Camille E.; Zhu, Fan; Lee, Andrew Y.

2014-10-01

The limited soft tissue visualization provided by computed tomography, the standard imaging modality for radiotherapy treatment planning and daily localization, has motivated studies on the use of magnetic resonance imaging (MRI) for better characterization of treatment sites, such as the prostate and head and neck. However, no studies have been conducted on MRI-based segmentation for the abdomen, a site that could greatly benefit from enhanced soft tissue targeting. We investigated the interobserver and intraobserver precision in segmentation of abdominal organs on MR images for treatment planning and localization. Manual segmentation of 8 abdominal organs was performed by 3 independent observersmore » on MR images acquired from 14 healthy subjects. Observers repeated segmentation 4 separate times for each image set. Interobserver and intraobserver contouring precision was assessed by computing 3-dimensional overlap (Dice coefficient [DC]) and distance to agreement (Hausdorff distance [HD]) of segmented organs. The mean and standard deviation of intraobserver and interobserver DC and HD values were DC{sub intraobserver} = 0.89 ± 0.12, HD{sub intraobserver} = 3.6 mm ± 1.5, DC{sub interobserver} = 0.89 ± 0.15, and HD{sub interobserver} = 3.2 mm ± 1.4. Overall, metrics indicated good interobserver/intraobserver precision (mean DC > 0.7, mean HD < 4 mm). Results suggest that MRI offers good segmentation precision for abdominal sites. These findings support the utility of MRI for abdominal planning and localization, as emerging MRI technologies, techniques, and onboard imaging devices are beginning to enable MRI-based radiotherapy.« less

Local Heat Flux Measurements with Single and Small Multi-element Coaxial Element-Injectors

NASA Technical Reports Server (NTRS)

Jones, Gregg; Protz, Christopher; Bullard, Brad; Hulka, James

2006-01-01

To support NASA's Vision for Space Exploration mission, the NASA Marshall Space Flight Center conducted a program in 2005 to improve the capability to predict local thermal compatibility and heat transfer in liquid propellant rocket engine combustion devices. The ultimate objective was to predict and hence reduce the local peak heat flux due to injector design, resulting in a significant improvement in overall engine reliability and durability. Such analyses are applicable to combustion devices in booster, upper stage, and in-space engines with regeneratively cooled chamber walls, as well as in small thrust chambers with few elements in the injector. In this program, single and three-element injectors were hot-fire tested with liquid oxygen and gaseous hydrogen propellants at The Pennsylvania State University Cryogenic Combustor Laboratory from May to August 2005. Local heat fluxes were measured in a 1-inch internal diameter heat sink combustion chamber using Medtherm coaxial thermocouples and Gardon heat flux gauges, Injector configurations were tested with both shear coaxial elements and swirl coaxial elements. Both a straight and a scarfed single element swirl injector were tested. This paper includes general descriptions of the experimental hardware, instrumentation, and results of the hot-fire testing for three coaxial shear and swirl elements. Detailed geometry and test results the for shear coax elements has already been published. Detailed test result for the remaining 6 swirl coax element for the will be published in a future JANNAF presentation to provide well-defined data sets for development and model validation.

Effect of Local Post Weld Heat Treatment on Tensile Properties in Friction Stir Welded 2219-O Al Alloy

NASA Astrophysics Data System (ADS)

Chu, Guannan; Sun, Lei; Lin, Caiyuan; Lin, Yanli

2017-11-01

To improve the formability of the aluminum alloy welds and overcome the size limitation of the bulk post weld heat treatment (BPWHT) on large size friction stir welded joints, a local post weld heat treatment method (LPWHT) was proposed. In this method, the resistance heating as the moving heat source is adopted to only heat the weld seam. The temperature field of LPWHT and its influence on the mechanical properties and formability of FSW 2219-O Al alloy joints was investigated. The evaluation of the tensile properties of FSW samples was also examined by mapping the global and local strain distribution using the digital image correlation methodology. The results indicated that the formability was improved greatly after LPWHT, while the hardness distribution of the FSW joint was homogenized. The maximum elongation can reach 1.4 times that of as-welded joints with increase the strength and the strain of the nugget zone increased from 3 to 8% when annealing at 300 °C. The heterogeneity on the tensile deformation of the as-welded joints was improved by the nugget zone showing large local strain value and the reason was given according to the dimple fracture characteristics at different annealing temperatures. The tensile strength and elongation of LPWHT can reach 93.3 and 96.1% of the BPWHT, respectively. Thus, the LPWHT can be advantageous compared to the BPWHT for large size welds.

Local Heat Flux Measurements with Single Element Coaxial Injectors

NASA Technical Reports Server (NTRS)

Jones, Gregg; Protz, Christopher; Bullard, Brad; Hulka, James

2006-01-01

To support the mission for the NASA Vision for Space Exploration, the NASA Marshall Space Flight Center conducted a program in 2005 to improve the capability to predict local thermal compatibility and heat transfer in liquid propellant rocket engine combustion devices. The ultimate objective was to predict and hence reduce the local peak heat flux due to injector design, resulting in a significant improvement in overall engine reliability and durability. Such analyses are applicable to combustion devices in booster, upper stage, and in-space engines, as well as for small thrusters with few elements in the injector. In this program, single element and three-element injectors were hot-fire tested with liquid oxygen and ambient temperature gaseous hydrogen propellants at The Pennsylvania State University Cryogenic Combustor Laboratory from May to August 2005. Local heat fluxes were measured in a 1-inch internal diameter heat sink combustion chamber using Medtherm coaxial thermocouples and Gardon heat flux gauges. Injectors were tested with shear coaxial and swirl coaxial elements, including recessed, flush and scarfed oxidizer post configurations, and concentric and non-concentric fuel annuli. This paper includes general descriptions of the experimental hardware, instrumentation, and results of the hot-fire testing for three of the single element injectors - recessed-post shear coaxial with concentric fuel, flush-post swirl coaxial with concentric fuel, and scarfed-post swirl coaxial with concentric fuel. Detailed geometry and test results will be published elsewhere to provide well-defined data sets for injector development and model validatation.

Process of optimization of district heat production by utilizing waste energy from metallurgical processes

NASA Astrophysics Data System (ADS)

Konovšek, Damjan; Fužir, Miran; Slatinek, Matic; Šepul, Tanja; Plesnik, Kristijan; Lečnik, Samo

2017-07-01

In a consortium with SIJ (Slovenian Steel Group), Metal Ravne, the local community of Ravne na Koro\\vskem and the public research Institut Jožef Stefan, with its registered office in Slovenia, Petrol Energetika, d.o.o. set up a technical and technological platform of an innovative energy case for a transition of steel industry into circular economy with a complete energy solution called »Utilization of Waste Heat from Metallurgical Processes for District Heating of Ravne na Koro\\vskem. This is the first such project designed for a useful utilization of waste heat in steel industry which uses modern technology and innovative system solutions for an integration of a smart, efficient and sustainable heating and cooling system and which shows a growth potential. This will allow the industry and cities to make energy savings, to improve the quality of air and to increase the benefits for the society we live in. On the basis of circular economy, we designed a target-oriented co-operation of economy, local community and public research institute to produce new business models where end consumers are put into the centre. This innovation opens the door for steel industry and local community to a joint aim that is a transition into efficient low-carbon energy systems which are based on involvement of natural local conditions, renewable energy sources, the use of waste heat and with respect for the principles of sustainable development.

Photosynthetic solar cell using nanostructured proton exchange membrane for microbial biofilm prevention.

PubMed

Lee, Dong Hyun; Oh, Hwa Jin; Bai, Seoung Jae; Song, Young Seok

2014-06-24

Unwanted biofilm formation has a detrimental effect on bioelectrical energy harvesting in microbial cells. This issue still needs to be solved for higher power and longer durability and could be resolved with the help of nanoengineering in designing and manufacturing. Here, we demonstrate a photosynthetic solar cell (PSC) that contains a nanostructure to prevent the formation of biofilm by micro-organisms. Nanostructures were fabricated using nanoimprint lithography, where a film heater array system was introduced to precisely control the local wall temperature. To understand the heat and mass transfer phenomena behind the manufacturing and energy harvesting processes of PSC, we carried out a numerical simulation and experimental measurements. It revealed that the nanostructures developed on the proton exchange membrane enable PSC to produce enhanced output power due to the retarded microbial attachment on the Nafion membrane. We anticipate that this strategy can provide a pathway where PSC can ensure more renewable, sustainable, and efficient energy harvesting performance.

Epidermal photonic devices for quantitative imaging of temperature and thermal transport characteristics of the skin

NASA Astrophysics Data System (ADS)

Gao, Li; Zhang, Yihui; Malyarchuk, Viktor; Jia, Lin; Jang, Kyung-In; Chad Webb, R.; Fu, Haoran; Shi, Yan; Zhou, Guoyan; Shi, Luke; Shah, Deesha; Huang, Xian; Xu, Baoxing; Yu, Cunjiang; Huang, Yonggang; Rogers, John A.

2014-09-01

Characterization of temperature and thermal transport properties of the skin can yield important information of relevance to both clinical medicine and basic research in skin physiology. Here we introduce an ultrathin, compliant skin-like, or ‘epidermal’, photonic device that combines colorimetric temperature indicators with wireless stretchable electronics for thermal measurements when softly laminated on the skin surface. The sensors exploit thermochromic liquid crystals patterned into large-scale, pixelated arrays on thin elastomeric substrates; the electronics provide means for controlled, local heating by radio frequency signals. Algorithms for extracting patterns of colour recorded from these devices with a digital camera and computational tools for relating the results to underlying thermal processes near the skin surface lend quantitative value to the resulting data. Application examples include non-invasive spatial mapping of skin temperature with milli-Kelvin precision (±50 mK) and sub-millimetre spatial resolution. Demonstrations in reactive hyperaemia assessments of blood flow and hydration analysis establish relevance to cardiovascular health and skin care, respectively.

Epidermal photonic devices for quantitative imaging of temperature and thermal transport characteristics of the skin.

PubMed

Gao, Li; Zhang, Yihui; Malyarchuk, Viktor; Jia, Lin; Jang, Kyung-In; Webb, R Chad; Fu, Haoran; Shi, Yan; Zhou, Guoyan; Shi, Luke; Shah, Deesha; Huang, Xian; Xu, Baoxing; Yu, Cunjiang; Huang, Yonggang; Rogers, John A

2014-09-19

Characterization of temperature and thermal transport properties of the skin can yield important information of relevance to both clinical medicine and basic research in skin physiology. Here we introduce an ultrathin, compliant skin-like, or 'epidermal', photonic device that combines colorimetric temperature indicators with wireless stretchable electronics for thermal measurements when softly laminated on the skin surface. The sensors exploit thermochromic liquid crystals patterned into large-scale, pixelated arrays on thin elastomeric substrates; the electronics provide means for controlled, local heating by radio frequency signals. Algorithms for extracting patterns of colour recorded from these devices with a digital camera and computational tools for relating the results to underlying thermal processes near the skin surface lend quantitative value to the resulting data. Application examples include non-invasive spatial mapping of skin temperature with milli-Kelvin precision (±50 mK) and sub-millimetre spatial resolution. Demonstrations in reactive hyperaemia assessments of blood flow and hydration analysis establish relevance to cardiovascular health and skin care, respectively.

On the possibility of control restoration in some inverse problems of heat and mass transfer

NASA Astrophysics Data System (ADS)

Bilchenko, G. G.; Bilchenko, N. G.

2016-11-01

The hypersonic aircraft permeable surfaces effective heat protection problems are considered. The physic-chemical processes (the dissociation and the ionization) in laminar boundary layer of compressible gas are appreciated in mathematical model. The statements of direct problems of heat and mass transfer are given: according to preset given controls it is necessary to compute the boundary layer mathematical model parameters and determinate the local and total heat flows and friction forces and the power of blowing system. The A.A.Dorodnicyn's generalized integral relations method has been used as calculation basis. The optimal control - the blowing into boundary layer (for continuous functions) was constructed as the solution of direct problem in extreme statement with the use of this approach. The statement of inverse problems are given: the control laws ensuring the preset given local heat flow and local tangent friction are restored. The differences between the interpolation and the approximation statements are discussed. The possibility of unique control restoration is established and proved (in the stagnation point). The computational experiments results are presented.

A Numerical Analysis on a Compact Heat Exchanger in Aluminum Foam

NASA Astrophysics Data System (ADS)

Buonomo, B.; Ercole, D.; Manca, O.; Nardini, S.

2016-09-01

A numerical investigation on a compact heat exchanger in aluminum foam is carried out. The governing equations in two-dimensional steady state regime are written in local thermal non-equilibrium (LTNE). The geometrical domain under investigation is made up of a plate in aluminum foam with inside a single array of five circular tubes. The presence of the open-celled metal foam is modeled as a porous media by means of the Darcy-Forchheimer law. The foam has a porosity of 0.93 with 20 pores per inch and the LTNE assumption is used to simulate the heat transfer between metal foam and air. The compact heat exchanger at different air flow rates is studied with an assigned surface tube temperature. The results in terms of local heat transfer coefficient and Nusselt number on the external surface of the tubes are given. Moreover, local air temperature and velocity profiles in the smaller cross section, between two consecutive tubes, as a function of Reynolds number are showed. The performance evaluation criteria (PEC) is assessed in order to evaluate the effectiveness of the metal foam.

Precision Airdrop (Largage de precision)

DTIC Science & Technology

2005-12-01

NAVIGATION TO A PRECISION AIRDROP OVERVIEW RTO-AG-300-V24 2 - 9 the point from various compass headings. As the tests are conducted, the resultant...rate. This approach avoids including a magnetic compass for the heading reference, which has difficulties due to local changes in the magnetic field...Scientifica della Difesa ROYAUME-UNI Via XX Settembre 123 Dstl Knowledge Services ESPAGNE 00187 Roma Information Centre, Building 247 SDG TECEN / DGAM

Evaluation of a fully automated treponemal test and comparison with conventional VDRL and FTA-ABS tests.

PubMed

Park, Yongjung; Park, Younhee; Joo, Shin Young; Park, Myoung Hee; Kim, Hyon-Suk

2011-11-01

We evaluated analytic performances of an automated treponemal test and compared this test with the Venereal Disease Research Laboratory test (VDRL) and fluorescent treponemal antibody absorption test (FTA-ABS). Precision performance of the Architect Syphilis TP assay (TP; Abbott Japan, Tokyo, Japan) was assessed, and 150 serum samples were assayed with the TP before and after heat inactivation to estimate the effect of heat inactivation. A total of 616 specimens were tested with the FTA-ABS and TP, and 400 were examined with the VDRL. The TP showed good precision performance with total imprecision of less than a 10% coefficient of variation. An excellent linear relationship between results before and after heat inactivation was observed (R(2) = 0.9961). The FTA-ABS and TP agreed well with a κ coefficient of 0.981. The concordance rate between the FTA-ABS and TP was the highest (99.0%), followed by the rates between FTA-ABS and VDRL (85.0%) and between TP and VDRL (83.8%). The automated TP assay may be adequate for screening for syphilis in a large volume of samples and can be an alternative to FTA-ABS.

Dancing the tight rope on the nanoscale—Calibrating a heat flux sensor of a scanning thermal microscope

NASA Astrophysics Data System (ADS)

Kloppstech, K.; Könne, N.; Worbes, L.; Hellmann, D.; Kittel, A.

2015-11-01

We report on a precise in situ procedure to calibrate the heat flux sensor of a near-field scanning thermal microscope. This sensitive thermal measurement is based on 1ω modulation technique and utilizes a hot wire method to build an accessible and controllable heat reservoir. This reservoir is coupled thermally by near-field interactions to our probe. Thus, the sensor's conversion relation V th ( QGS ∗ ) can be precisely determined. Vth is the thermopower generated in the sensor's coaxial thermocouple and QGS ∗ is the thermal flux from reservoir through the sensor. We analyze our method with Gaussian error calculus with an error estimate on all involved quantities. The overall relative uncertainty of the calibration procedure is evaluated to be about 8% for the measured conversion constant, i.e., (2.40 ± 0.19) μV/μW. Furthermore, we determine the sensor's thermal resistance to be about 0.21 K/μW and find the thermal resistance of the near-field mediated coupling at a distance between calibration standard and sensor of about 250 pm to be 53 K/μW.

Study on Heat Transfer Agent Models of Transmission Line and Transformer

NASA Astrophysics Data System (ADS)

Wang, B.; Zhang, P. P.

2018-04-01

When using heat transfer simulation to study the dynamic overload of transmission line and transformer, it needs to establish the mathematical expression of heat transfer. However, the formula is a nonlinear differential equation or equation set and it is not easy to get general solutions. Aiming at this problem, some different temperature change processes caused by different initial conditions are calculated by differential equation and equation set. New agent models are developed according to the characteristics of different temperature change processes. The results show that the agent models have high precision and can solve the problem that the original equation cannot be directly applied in some practical engineers.

An evaluation of a zero-heat-flux cutaneous thermometer in cardiac surgical patients.

PubMed

Eshraghi, Yashar; Nasr, Vivian; Parra-Sanchez, Ivan; Van Duren, Albert; Botham, Mark; Santoscoy, Thomas; Sessler, Daniel I

2014-09-01

Although core temperature can be measured invasively, there are currently no widely available, reliable, noninvasive thermometers for its measurement. We thus compared a prototype zero-heat-flux thermometer with simultaneous measurements from a pulmonary artery catheter. Specifically, we tested the hypothesis that zero-heat-flux temperatures are sufficiently accurate for routine clinical use. Core temperature was measured from the thermistor of a standard pulmonary artery catheter and with a prototype zero-heat-flux deep-tissue thermometer in 105 patients having nonemergent cardiac surgery. Zero-heat-flux probes were positioned on the lateral forehead and lateral neck. Skin surface temperature probes were attached to the forehead just adjacent to the zero-heat-flux probe. Temperatures were recorded at 1-minute intervals, excluding the period of cardiopulmonary bypass, and for the first 4 postoperative hours. Zero-heat-flux and pulmonary artery temperatures were compared with bias analysis; differences exceeding 0.5°C were considered to be potentially clinically important. The mean duration in the operating room was 279 ± 75 minutes, and the mean cross-clamp time was 118 ± 50 minutes. All subjects were monitored for an additional 4 hours in the intensive care unit. The average overall difference between forehead zero-heat-flux and pulmonary artery temperatures (i.e., forehead minus pulmonary artery) was -0.23°C (95% limits of agreement of ±0.82); 78% of the differences were ≤0.5°C. The average intraoperative temperature difference was -0.08°C (95% limits of agreement of ±0.88); 84% of the differences were ≤0.5°C. The average postoperative difference was -0.32°C (95% limits of agreement of ±0.75); 84% of the differences were ≤0.5°C. Bias and precision values for neck site were similar to the forehead values. Uncorrected forehead skin temperature showed an increasing negative bias as core temperature decreased. Core temperature can be noninvasively measured using the zero-heat-flux method. Bias was small, but precision was slightly worse than our designated 0.5°C limits compared with measurements from a pulmonary artery catheter.

The Cosmological Impact of Luminous TeV Blazars. II. Rewriting the Thermal History of the Intergalactic Medium

NASA Astrophysics Data System (ADS)

Chang, Philip; Broderick, Avery E.; Pfrommer, Christoph

2012-06-01

The universe is opaque to extragalactic very high energy gamma rays (VHEGRs, E > 100 GeV) because they annihilate and pair produce on the extragalactic background light. The resulting ultrarelativistic pairs are commonly assumed to lose energy primarily through inverse Compton scattering of cosmic microwave background (CMB) photons, reprocessing the original emission from TeV to GeV energies. In Broderick et al., we argued that this is not the case; powerful plasma instabilities driven by the highly anisotropic nature of the ultrarelativistic pair distribution provide a plausible way to dissipate the kinetic energy of the TeV-generated pairs locally, heating the intergalactic medium (IGM). Here, we explore the effect of this heating on the thermal history of the IGM. We collate the observed extragalactic VHEGR sources to determine a local VHEGR heating rate. Given the pointed nature of VHEGR observations, we estimate the correction for the various selection effects using Fermi observations of high- and intermediate-peaked BL Lac objects. As the extragalactic component of the local VHEGR flux is dominated by TeV blazars, we then estimate the evolution of the TeV blazar luminosity density by tying it to the well-observed quasar luminosity density and producing a VHEGR heating rate as a function of redshift. This heating is relatively homogeneous for z <~ 4, but there is greater spatial variation at higher redshift (order unity at z ~ 6) because of the reduced number of blazars that contribute to local heating. We show that this new heating process dominates photoheating in the low-redshift evolution of the IGM and calculate the effect of this heating in a one-zone model. As a consequence, the inclusion of TeV blazar heating qualitatively and quantitatively changes the structure and history of the IGM. Due to the homogeneous nature of the extragalactic background light, TeV blazars produce a uniform volumetric heating rate. This heating is sufficient to increase the temperature of the mean density IGM by nearly an order of magnitude, and at low densities by substantially more. It also naturally produces the inverted temperature-density relation inferred by recent observations of the high-redshift Lyα forest, a feature that is difficult to reconcile with standard reionization models. Finally, we close with a discussion on the possibility of detecting this hot low-density IGM suggested by our model either directly or indirectly via the local Lyα forest, the Comptonized CMB, or free-free emission, but we find that such measurements are currently not feasible.

Experimental Methodology for Estimation of Local Heat Fluxes and Burning Rates in Steady Laminar Boundary Layer Diffusion Flames.

PubMed

Singh, Ajay V; Gollner, Michael J

2016-06-01

Modeling the realistic burning behavior of condensed-phase fuels has remained out of reach, in part because of an inability to resolve the complex interactions occurring at the interface between gas-phase flames and condensed-phase fuels. The current research provides a technique to explore the dynamic relationship between a combustible condensed fuel surface and gas-phase flames in laminar boundary layers. Experiments have previously been conducted in both forced and free convective environments over both solid and liquid fuels. A unique methodology, based on the Reynolds Analogy, was used to estimate local mass burning rates and flame heat fluxes for these laminar boundary layer diffusion flames utilizing local temperature gradients at the fuel surface. Local mass burning rates and convective and radiative heat feedback from the flames were measured in both the pyrolysis and plume regions by using temperature gradients mapped near the wall by a two-axis traverse system. These experiments are time-consuming and can be challenging to design as the condensed fuel surface burns steadily for only a limited period of time following ignition. The temperature profiles near the fuel surface need to be mapped during steady burning of a condensed fuel surface at a very high spatial resolution in order to capture reasonable estimates of local temperature gradients. Careful corrections for radiative heat losses from the thermocouples are also essential for accurate measurements. For these reasons, the whole experimental setup needs to be automated with a computer-controlled traverse mechanism, eliminating most errors due to positioning of a micro-thermocouple. An outline of steps to reproducibly capture near-wall temperature gradients and use them to assess local burning rates and heat fluxes is provided.

Experimental Methodology for Estimation of Local Heat Fluxes and Burning Rates in Steady Laminar Boundary Layer Diffusion Flames

PubMed Central

Singh, Ajay V.; Gollner, Michael J.

2016-01-01

Modeling the realistic burning behavior of condensed-phase fuels has remained out of reach, in part because of an inability to resolve the complex interactions occurring at the interface between gas-phase flames and condensed-phase fuels. The current research provides a technique to explore the dynamic relationship between a combustible condensed fuel surface and gas-phase flames in laminar boundary layers. Experiments have previously been conducted in both forced and free convective environments over both solid and liquid fuels. A unique methodology, based on the Reynolds Analogy, was used to estimate local mass burning rates and flame heat fluxes for these laminar boundary layer diffusion flames utilizing local temperature gradients at the fuel surface. Local mass burning rates and convective and radiative heat feedback from the flames were measured in both the pyrolysis and plume regions by using temperature gradients mapped near the wall by a two-axis traverse system. These experiments are time-consuming and can be challenging to design as the condensed fuel surface burns steadily for only a limited period of time following ignition. The temperature profiles near the fuel surface need to be mapped during steady burning of a condensed fuel surface at a very high spatial resolution in order to capture reasonable estimates of local temperature gradients. Careful corrections for radiative heat losses from the thermocouples are also essential for accurate measurements. For these reasons, the whole experimental setup needs to be automated with a computer-controlled traverse mechanism, eliminating most errors due to positioning of a micro-thermocouple. An outline of steps to reproducibly capture near-wall temperature gradients and use them to assess local burning rates and heat fluxes is provided. PMID:27285827

Dependence of L-mode confinement on the electron cyclotron power deposition profile in the TCV tokamak

NASA Astrophysics Data System (ADS)

Kirneva, N. A.; Razumova, K. A.; Pochelon, A.; Behn, R.; Coda, S.; Curchod, L.; Duval, B. P.; Goodman, T. P.; Labit, B.; Karpushov, A. N.; Rancic, M.; Sauter, O.; Silva, M.; TCV Team

2012-01-01

Scenarios with different electron cyclotron heating power profile distributions and widths were compared for the first time in experiments on the Tokamak à Configuration Variable (TCV). The heating profile was changed from shot to shot over a wide range from localized on-axis, with normalized minor radius half-width at half maximum σ1/2 ~ 0.1, up to a widely distributed heating power profile with σ1/2 ~ 0.4 and finally to a profile peaked far off-axis. The global confinement, MHD activity, density, temperature and electron pressure profile evolution were compared. In particular, the energy confinement properties of discharges with localized on-axis heating and distributed on-axis heating were very similar, with degradation close to that predicted by the ITER L-mode scaling; in the case of off-axis heating, on the other hand, the confinement degradation was even stronger.

Precise Truss Assembly using Commodity Parts and Low Precision Welding

NASA Technical Reports Server (NTRS)

Komendera, Erik; Reishus, Dustin; Dorsey, John T.; Doggett, William R.; Correll, Nikolaus

2013-01-01

We describe an Intelligent Precision Jigging Robot (IPJR), which allows high precision assembly of commodity parts with low-precision bonding. We present preliminary experiments in 2D that are motivated by the problem of assembling a space telescope optical bench on orbit using inexpensive, stock hardware and low-precision welding. An IPJR is a robot that acts as the precise "jigging", holding parts of a local assembly site in place while an external low precision assembly agent cuts and welds members. The prototype presented in this paper allows an assembly agent (in this case, a human using only low precision tools), to assemble a 2D truss made of wooden dowels to a precision on the order of millimeters over a span on the order of meters. We report the challenges of designing the IPJR hardware and software, analyze the error in assembly, document the test results over several experiments including a large-scale ring structure, and describe future work to implement the IPJR in 3D and with micron precision.

A localization algorithm of adaptively determining the ROI of the reference circle in image

NASA Astrophysics Data System (ADS)

Xu, Zeen; Zhang, Jun; Zhang, Daimeng; Liu, Xiaomao; Tian, Jinwen

2018-03-01

Aiming at solving the problem of accurately positioning the detection probes underwater, this paper proposed a method based on computer vision which can effectively solve this problem. The theory of this method is that: First, because the shape information of the heat tube is similar to a circle in the image, we can find a circle which physical location is well known in the image, we set this circle as the reference circle. Second, we calculate the pixel offset between the reference circle and the probes in the picture, and adjust the steering gear through the offset. As a result, we can accurately measure the physical distance between the probes and the under test heat tubes, then we can know the precise location of the probes underwater. However, how to choose reference circle in image is a difficult problem. In this paper, we propose an algorithm that can adaptively confirm the area of reference circle. In this area, there will be only one circle, and the circle is the reference circle. The test results show that the accuracy of the algorithm of extracting the reference circle in the whole picture without using ROI (region of interest) of the reference circle is only 58.76% and the proposed algorithm is 95.88%. The experimental results indicate that the proposed algorithm can effectively improve the efficiency of the tubes detection.

Hot cracking of Structural Steel during Laser Welding

NASA Astrophysics Data System (ADS)

Pineda Huitron, Rosa M.; Vuorinen, Esa

2017-10-01

Laser welding is an important technique in many industries due to its high precision in operation, its local and fast processing, narrow welds and its good weld surface quality. However, the process can involve some complications due to the rapid heating and cooling of the material processed, resulting in physical and metallurgical effects as thermal contraction during solidification, giving as a result the presence of residual stresses in the narrow weld. Formation of defects during the process is an important topic to be evaluated in order to achieve better performance of the steels in use. In the present work, defects formed during laser welding of a structural steel have been investigated. The defects formed have been identified and the causes of the defects are discussed. Possible strategies for improvement of the welding procedure and final weld result are proposed. The defects were analysed by optical and scanning electron microscopy and hardness measurement. Cracks were located in the middle of the fusion zone and followed both inter-granular and trans-granular paths. Impurities as manganese sulphides were found along the welding direction, and could act as sites for crack formation. The cracks formed during solidification of the weld are identified as solidification cracks. This kind of cracks is usually caused by solidification shrinkage and thermal contractions during the process, which appear in the fusion zone and sometimes in the heat affected zone.

A Transport Model for Non-Local Heating of Electrons in ICP Reactors

NASA Technical Reports Server (NTRS)

Chang, C. H.; Bose, Deepak; Arnold, James O. (Technical Monitor)

1998-01-01

A new model has been developed for non-local heating of electrons in ICP reactors, based on a hydrodynamic approach. The model has been derived using the electron momentum conservation in azimuthal direction with electromagnetic and frictional forces respectively as driving force and damper of harmonic oscillatory motion of electrons. The resulting transport equations include the convection of azimuthal electron momentum in radial and axial directions, thereby accounting for the non-local effects. The azimuthal velocity of electrons and the resulting electrical current are coupled to the Maxwell's relations, thus forming a self-consistent model for non-local heating. This model is being implemented along with a set of Navier-Stokes equations for plasma dynamics and gas flow to simulate low-pressure (few mTorr's) ICP discharges. Characteristics of nitrogen plasma in a TCP 300mm etch reactor is being studied. The results will be compared against the available Langmuir probe measurements.

Spatial control of chemical processes on nanostructures through nano-localized water heating.

PubMed

Jack, Calum; Karimullah, Affar S; Tullius, Ryan; Khorashad, Larousse Khosravi; Rodier, Marion; Fitzpatrick, Brian; Barron, Laurence D; Gadegaard, Nikolaj; Lapthorn, Adrian J; Rotello, Vincent M; Cooke, Graeme; Govorov, Alexander O; Kadodwala, Malcolm

2016-03-10

Optimal performance of nanophotonic devices, including sensors and solar cells, requires maximizing the interaction between light and matter. This efficiency is optimized when active moieties are localized in areas where electromagnetic (EM) fields are confined. Confinement of matter in these 'hotspots' has previously been accomplished through inefficient 'top-down' methods. Here we report a rapid 'bottom-up' approach to functionalize selective regions of plasmonic nanostructures that uses nano-localized heating of the surrounding water induced by pulsed laser irradiation. This localized heating is exploited in a chemical protection/deprotection strategy to allow selective regions of a nanostructure to be chemically modified. As an exemplar, we use the strategy to enhance the biosensing capabilities of a chiral plasmonic substrate. This novel spatially selective functionalization strategy provides new opportunities for efficient high-throughput control of chemistry on the nanoscale over macroscopic areas for device fabrication.

Application of precise altimetry to the study of precise leveling of the sea surface, the Earth's gravity field, and the rotation of the Earth

NASA Technical Reports Server (NTRS)

Segawa, J.; Ganeko, Y.; Sasaki, M.; Mori, T.; Ooe, M.; Nakagawa, I.; Ishii, H.; Hagiwara, Y.

1991-01-01

Our program includes five research items: (1) determination of a precision geoid and gravity anomaly field; (2) precise leveling and detection of tidal changes of the sea surface and study of the role of the tide in the global energy exchange; (3) oceanic effect on the Earth's rotation and polar motion; (4) geological and geophysical interpretation of the altimetry gravity field; and (5) evaluation of the effectiveness of local tracking of TOPEX/POSEIDON by use of a laser tracker.

Transport lattice models of heat transport in skin with spatially heterogeneous, temperature-dependent perfusion.

PubMed

Gowrishankar, T R; Stewart, Donald A; Martin, Gregory T; Weaver, James C

2004-11-17

Investigation of bioheat transfer problems requires the evaluation of temporal and spatial distributions of temperature. This class of problems has been traditionally addressed using the Pennes bioheat equation. Transport of heat by conduction, and by temperature-dependent, spatially heterogeneous blood perfusion is modeled here using a transport lattice approach. We represent heat transport processes by using a lattice that represents the Pennes bioheat equation in perfused tissues, and diffusion in nonperfused regions. The three layer skin model has a nonperfused viable epidermis, and deeper regions of dermis and subcutaneous tissue with perfusion that is constant or temperature-dependent. Two cases are considered: (1) surface contact heating and (2) spatially distributed heating. The model is relevant to the prediction of the transient and steady state temperature rise for different methods of power deposition within the skin. Accumulated thermal damage is estimated by using an Arrhenius type rate equation at locations where viable tissue temperature exceeds 42 degrees C. Prediction of spatial temperature distributions is also illustrated with a two-dimensional model of skin created from a histological image. The transport lattice approach was validated by comparison with an analytical solution for a slab with homogeneous thermal properties and spatially distributed uniform sink held at constant temperatures at the ends. For typical transcutaneous blood gas sensing conditions the estimated damage is small, even with prolonged skin contact to a 45 degrees C surface. Spatial heterogeneity in skin thermal properties leads to a non-uniform temperature distribution during a 10 GHz electromagnetic field exposure. A realistic two-dimensional model of the skin shows that tissue heterogeneity does not lead to a significant local temperature increase when heated by a hot wire tip. The heat transport system model of the skin was solved by exploiting the mathematical analogy between local thermal models and local electrical (charge transport) models, thereby allowing robust, circuit simulation software to obtain solutions to Kirchhoff's laws for the system model. Transport lattices allow systematic introduction of realistic geometry and spatially heterogeneous heat transport mechanisms. Local representations for both simple, passive functions and more complex local models can be easily and intuitively included into the system model of a tissue.

Apparatus for precision micromachining with lasers

DOEpatents

Chang, J.J.; Dragon, E.P.; Warner, B.E.

1998-04-28

A new material processing apparatus using a short-pulsed, high-repetition-rate visible laser for precision micromachining utilizes a near diffraction limited laser, a high-speed precision two-axis tilt-mirror for steering the laser beam, an optical system for either focusing or imaging the laser beam on the part, and a part holder that may consist of a cover plate and a back plate. The system is generally useful for precision drilling, cutting, milling and polishing of metals and ceramics, and has broad application in manufacturing precision components. Precision machining has been demonstrated through percussion drilling and trepanning using this system. With a 30 W copper vapor laser running at multi-kHz pulse repetition frequency, straight parallel holes with size varying from 500 microns to less than 25 microns and with aspect ratios up to 1:40 have been consistently drilled with good surface finish on a variety of metals. Micromilling and microdrilling on ceramics using a 250 W copper vapor laser have also been demonstrated with good results. Materialographic sections of machined parts show little (submicron scale) recast layer and heat affected zone. 1 fig.

Apparatus for precision micromachining with lasers

DOEpatents

Chang, Jim J.; Dragon, Ernest P.; Warner, Bruce E.

1998-01-01

A new material processing apparatus using a short-pulsed, high-repetition-rate visible laser for precision micromachining utilizes a near diffraction limited laser, a high-speed precision two-axis tilt-mirror for steering the laser beam, an optical system for either focusing or imaging the laser beam on the part, and a part holder that may consist of a cover plate and a back plate. The system is generally useful for precision drilling, cutting, milling and polishing of metals and ceramics, and has broad application in manufacturing precision components. Precision machining has been demonstrated through percussion drilling and trepanning using this system. With a 30 W copper vapor laser running at multi-kHz pulse repetition frequency, straight parallel holes with size varying from 500 microns to less than 25 microns and with aspect ratios up to 1:40 have been consistently drilled with good surface finish on a variety of metals. Micromilling and microdrilling on ceramics using a 250 W copper vapor laser have also been demonstrated with good results. Materialogroaphic sections of machined parts show little (submicron scale) recast layer and heat affected zone.

Public Data Set: Continuous, Edge Localized Ion Heating During Non-Solenoidal Plasma Startup and Sustainment in a Low Aspect Ratio Tokamak

DOE Data Explorer

Burke, Marcus G. [University of Wisconsin-Madison] (ORCID:0000000176193724); Barr, Jayson L. [University of Wisconsin-Madison] (ORCID:0000000177685931); Bongard, Michael W. [University of Wisconsin-Madison] (ORCID:0000000231609746); Fonck, Raymond J. [University of Wisconsin-Madison] (ORCID:0000000294386762); Hinson, Edward T. [University of Wisconsin-Madison] (ORCID:000000019713140X); Perry, Justin M. [University of Wisconsin-Madison] (ORCID:0000000171228609); Reusch, Joshua A. [University of Wisconsin-Madison] (ORCID:0000000284249422); Schlossberg, David J. [University of Wisconsin-Madison] (ORCID:0000000287139448)

2017-05-16

This public data set contains openly-documented, machine readable digital research data corresponding to figures published in M.G. Burke et. al., 'Continuous, Edge Localized Ion Heating During Non-Solenoidal Plasma Startup and Sustainment in a Low Aspect Ratio Tokamak,' Nucl. Fusion 57, 076010 (2017).

Probabilistic metrology or how some measurement outcomes render ultra-precise estimates

NASA Astrophysics Data System (ADS)

Calsamiglia, J.; Gendra, B.; Muñoz-Tapia, R.; Bagan, E.

2016-10-01

We show on theoretical grounds that, even in the presence of noise, probabilistic measurement strategies (which have a certain probability of failure or abstention) can provide, upon a heralded successful outcome, estimates with a precision that exceeds the deterministic bounds for the average precision. This establishes a new ultimate bound on the phase estimation precision of particular measurement outcomes (or sequence of outcomes). For probe systems subject to local dephasing, we quantify such precision limit as a function of the probability of failure that can be tolerated. Our results show that the possibility of abstaining can set back the detrimental effects of noise.

Low Temperature Specific Heat in Lightly Mn-Substituted Electron-Doped SrTiO3

NASA Astrophysics Data System (ADS)

Okuda, Tetsuji; Hata, Hiroto; Eto, Takahiro; Sobaru, Shogo; Oda, Ryosuke; Noda, Masaaki; Kuwahara, Hideki

2017-08-01

We found large changes in the low-temperature specific heat (low-T C) in the lightly Mn-substituted electron-doped perovskites Sr0.95La0.05Ti1-yMnzO3 with y = 0.02 and 0.04 by applying magnetic fields up to 9 T. The changes in the low-T C are qualitatively well explained by the Schottky specific heat (CSch) of localized spins of the Mn 3d electrons in weak internal magnetic fields via itinerant electrons. However, the actual numbers of localized spins estimated from CSch are about 30% smaller than the expected values. Part of the localized spins of the Mn 3d electrons may disappear due to Kondo coupling with the itinerant electrons.

Solution of Radiation and Convection Heat-Transfer Problems

NASA Technical Reports Server (NTRS)

Oneill, R. F.

1986-01-01

Computer program P5399B developed to accommodate variety of fin-type heat conduction applications involving radiative or convective boundary conditions with additionally imposed local heat flux. Program also accommodates significant variety of one-dimensional heat-transfer problems not corresponding specifically to fin-type applications. Program easily accommodates all but few specialized one-dimensional heat-transfer analyses as well as many twodimensional analyses.

Profile shape optimization in multi-jet impingement cooling of dimpled topologies for local heat transfer enhancement

NASA Astrophysics Data System (ADS)

Negi, Deepchand Singh; Pattamatta, Arvind

2015-04-01

The present study deals with shape optimization of dimples on the target surface in multi-jet impingement heat transfer. Bezier polynomial formulation is incorporated to generate profile shapes for the dimple profile generation and a multi-objective optimization is performed. The optimized dimple shape exhibits higher local Nusselt number values compared to the reference hemispherical dimpled plate optimized shape which can be used to alleviate local temperature hot spots on target surface.

Measurements of Heat-Transfer and Friction Coefficients for Helium Flowing in a Tube at Surface Temperatures up to 5900 Deg R

NASA Technical Reports Server (NTRS)

Taylor, Maynard F.; Kirchgessner, Thomas A.

1959-01-01

Measurements of average heat transfer and friction coefficients and local heat transfer coefficients were made with helium flowing through electrically heated smooth tubes with length-diameter ratios of 60 and 92 for the following range of conditions: Average surface temperature from 1457 to 4533 R, Reynolds numbe r from 3230 to 60,000, heat flux up to 583,200 Btu per hr per ft2 of heat transfer area, and exit Mach numbe r up to 1.0. The results indicate that, in the turbulent range of Reynolds number, good correlation of the local heat transfer coefficients is obtained when the physical properties and density of helium are evaluated at the surface temperature. The average heat transfer coefficients are best correlated on the basis that the coefficient varies with [1 + (L/D))(sup -0,7)] and that the physical properties and density are evaluated at the surface temperature. The average friction coefficients for the tests with no heat addition are in complete agreement with the Karman-Nikuradse line. The average friction coefficients for heat addition are in poor agreement with the accepted line.

HEATING OF THE WARM IONIZED MEDIUM BY LOW-ENERGY COSMIC RAYS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Walker, Mark A., E-mail: Mark.Walker@manlyastrophysics.org

2016-02-10

In light of evidence for a high ionization rate due to low-energy cosmic rays (LECR) in diffuse molecular gas in the solar neighborhood, we evaluate their heat input to the warm ionized medium (WIM). LECR are much more effective at heating plasma than they are at heating neutrals. We show that the upper end of the measured ionization rates corresponds to a local LECR heating rate sufficient to maintain the WIM against radiative cooling, independent of the nature of the ionizing particles or the detailed shape of their spectrum. Elsewhere in the Galaxy the LECR heating rates may be highermore » than those measured locally. In particular, higher fluxes of LECR have been suggested for the inner Galactic disk, based on the observed hard X-ray emission, with correspondingly larger heating rates implied for the WIM. We conclude that LECR play an important and perhaps dominant role in the thermal balance of the WIM.« less

Heat flow and energetics of the San Andreas fault zone.

USGS Publications Warehouse

Lachenbruch, A.H.; Sass, J.H.

1980-01-01

Approximately 100 heat flow measurements in the San Andreas fault zone indicate 1) there is no evidence for local frictional heating of the main fault trace at any latitude over a 1000-km length from Cape Mendocino to San Bernardino, 2) average heat flow is high (ca.2 HFU, ca.80 mW m-2) throughout the 550-km segment of the Coast Ranges that encloses the San Andreas fault zone in central California; this broad anomaly falls off rapidly toward the Great Valley to the east, and over a 200-km distance toward the Mendocino Triple Junction to the northwest. As others have pointed out, a local conductive heat flow anomaly would be detectable unless the frictional resistance allocated to heat production on the main trace were less than 100 bars. Frictional work allocated to surface energy of new fractures is probably unimportant, and hydrologic convection is not likely to invalidate the conduction assumption, since the heat discharge by thermal springs near the fault is negligible. -Authors

Heat Vulnerability Index Mapping for Milwaukee and Wisconsin.

PubMed

Christenson, Megan; Geiger, Sarah Dee; Phillips, Jeffrey; Anderson, Ben; Losurdo, Giovanna; Anderson, Henry A

Extreme heat waves elevate the population's risk for heat-related morbidity and mortality, specifically for vulnerable groups such as older adults and young children. In this context, we developed 2 Heat Vulnerability Indices (HVIs), one for the state of Wisconsin and one for the Milwaukee metropolitan area. Through the creation of an HVI, state and local agencies will be able to use the indices as a planning tool for extreme heat events. Data used for the HVIs were grouped into 4 categories: (1) population density; (2) health factors; (3) demographic and socioeconomic factors; and (4) natural and built environment factors. These categories were mapped at the Census block group level. Unweighted z-score data were used to determine index scores, which were then mapped by quantiles ranging from "high" to "low" vulnerability. Statewide, Menominee County exhibited the highest vulnerability to extreme heat. Milwaukee HVI findings indicated high vulnerability in the city's inner core versus low vulnerability along the lakeshore. Visualization of vulnerability could help local public health agencies prepare for future extreme heat events.

Sustaining Engagements for Integrated Heat-Health Information Systems

NASA Astrophysics Data System (ADS)

Trtanj, J.

2016-12-01

Extreme heat events are on the rise, evidenced by the record breaking heat in the summer of 2016 in the US, increased heat-related death toll in south Asia, and projections from the Intergovernmental Panel on Climate Change. The impacts, responses and adaptation to extreme heat are inherently local or region in nature and require multisector engagement to manage current and future heat risks. Understanding the character of the information demand, who needs it, when and how it is needed, how it is used, and the remaining research questions, requires sustained engagement of multiple science and decision making communities. The construct of Integrated Information Systems provides the framework that sustains this dialogue, supports the production of useful information, and the translation of knowledge to action. The National Integrated Heat Health Information System (NIHHIS), a multi-agency collaboration, working at state, local and international levels, designed to facilitate an integrated approach to providing a suite of decision support services that reduce heat-related illness and death. NIHHIS sustains engagement across the public health, emergency management, disaster risk reduction, planning, housing, communication, climate, weather and other science communities. This presentation will highlight NIHHS sustained engagements in the Rio Grande Bravo region, other NIHHIS pilots, and international efforts building on the NIHHIS framework. NIHHIS, launched by the National Oceanic and Atmospheric Administration and the Centers for Disease Control and Prevention in 2015, now has over eight Federal partners and a burgeoning mix of pilots, projects and partners at state, local and international levels.

Heat transfer about a vertical permeable membrane

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kaviany, M.

1988-05-01

The natural convection heat transfer about both sides of vertical walls without any seepage has been studied and the effects of the wall thickness and thermal conductivity on the local and average heat transfer rates have been determined. Viskanta and Lankford have concluded that in predicting the heat transfer rate through the wall, for low-thermal-conductivity walls the a priori unknown wall surface temperatures can be walls the a priori unknown wall surface temperatures can be estimated as the arithmetic average of the reservoir temperatures without loss of accuracy (for most practical situations). Sparrow and Prakash treated the surface temperature asmore » variable but used the local temperature along with the available isothermal boundary-layer analysis for determination of the local heat transfer rate and found this to be reasonable at relatively low Grashof numbers. In this study the heat trasnfer rate between two reservoirs of different temperature connected in part through a permeable membrane is analyzed. Rather than solving the complete problem numerically for the three domains (fluid-wall-fluid), the available results on the effects of suction and blowing on the natural convection boundary layer are used in an analysis of the membranes with low thermal conductivity and small seepage velocities, which are characteristic of membranes considered. This will lead to rather simple expressions for the determination of the heat transfer rate.« less

A ‘self-adjustment’ mechanism for mixed-layer heat budget in the equatorial Atlantic cold tongue

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shi, Yanyan; Wang, Bin; Huang, Wenyu

Wind forcing is one of the most important sources for the oceanic energy cycle and is especially critical to the heat budget of surface mixed layer. The sensitivity of heat budget in the equatorial Atlantic cold tongue (EACT) region (5°S–5°N, 25°W–5°E) to wind forcing and the related mechanism are explored in this study. Based on the experiments forced by different wind forcing from both reanalysis and idealized datasets, it is revealed that the contribution ratio for each of the dominant physical processes in the heat budget is insensitive (the variations within 1% of the mean) to the variations in themore » local winds (the largest variation is about 20% of the mean) over the EACT region. Therefore, a ‘self-adjustment’ mechanism exists in the mixed-layer heat budget: as local zonal winds over the EACT region strengthen (weaken), both the cooling effects of turbulent mixing and the combined warming effects of surface net heat flux and zonal advection simultaneously increase (decrease) by nearly the same percentage and thus their contribution ratios are kept constant. Finally, owing to the impact of meridional winds on each term of heat budget can be neglected, the above mechanism is also tenable under the situation when the local meridional winds change.« less

A ‘self-adjustment’ mechanism for mixed-layer heat budget in the equatorial Atlantic cold tongue

DOE PAGES

Shi, Yanyan; Wang, Bin; Huang, Wenyu

2017-01-20

Wind forcing is one of the most important sources for the oceanic energy cycle and is especially critical to the heat budget of surface mixed layer. The sensitivity of heat budget in the equatorial Atlantic cold tongue (EACT) region (5°S–5°N, 25°W–5°E) to wind forcing and the related mechanism are explored in this study. Based on the experiments forced by different wind forcing from both reanalysis and idealized datasets, it is revealed that the contribution ratio for each of the dominant physical processes in the heat budget is insensitive (the variations within 1% of the mean) to the variations in themore » local winds (the largest variation is about 20% of the mean) over the EACT region. Therefore, a ‘self-adjustment’ mechanism exists in the mixed-layer heat budget: as local zonal winds over the EACT region strengthen (weaken), both the cooling effects of turbulent mixing and the combined warming effects of surface net heat flux and zonal advection simultaneously increase (decrease) by nearly the same percentage and thus their contribution ratios are kept constant. Finally, owing to the impact of meridional winds on each term of heat budget can be neglected, the above mechanism is also tenable under the situation when the local meridional winds change.« less

Seeking How Rocky Planets Form

NASA Image and Video Library

2018-01-25

This is an artist's rendition of the InSight lander. InSight is short for Interior Exploration using Seismic Investigations, Geodesy and Heat Transport. InSight is a Mars mission, but it's more than a Mars mission. The lander seeks the fingerprints of the processes that formed the rocky planets of the solar system, more than 4 billion years ago. It measures the planet's "vital signs:" its "pulse" (seismology), "temperature" (heat flow) and "reflexes" (precision tracking). https://photojournal.jpl.nasa.gov/catalog/PIA22229

Startup analysis for a high temperature gas loaded heat pipe

NASA Technical Reports Server (NTRS)

Sockol, P. M.

1973-01-01

A model for the rapid startup of a high-temperature gas-loaded heat pipe is presented. A two-dimensional diffusion analysis is used to determine the rate of energy transport by the vapor between the hot and cold zones of the pipe. The vapor transport rate is then incorporated in a simple thermal model of the startup of a radiation-cooled heat pipe. Numerical results for an argon-lithium system show that radial diffusion to the cold wall can produce large vapor flow rates during a rapid startup. The results also show that startup is not initiated until the vapor pressure p sub v in the hot zone reaches a precise value proportional to the initial gas pressure p sub i. Through proper choice of p sub i, startup can be delayed until p sub v is large enough to support a heat-transfer rate sufficient to overcome a thermal load on the heat pipe.

Physics responsible for heating efficiency and self-controlled temperature rise of magnetic nanoparticles in magnetic hyperthermia therapy.

PubMed

Shaterabadi, Zhila; Nabiyouni, Gholamreza; Soleymani, Meysam

2018-03-01

Magnetic nanoparticles as heat-generating nanosources in hyperthermia treatment are still faced with many drawbacks for achieving sufficient clinical potential. In this context, increase in heating ability of magnetic nanoparticles in a biologically safe alternating magnetic field and also approach to a precise control on temperature rise are two challenging subjects so that a significant part of researchers' efforts has been devoted to them. Since a deep understanding of Physics concepts of heat generation by magnetic nanoparticles is essential to develop hyperthermia as a cancer treatment with non-adverse side effects, this review focuses on different mechanisms responsible for heat dissipation in a radio frequency magnetic field. Moreover, particular attention is given to ferrite-based nanoparticles because of their suitability in radio frequency magnetic fields. Also, the key role of Curie temperature in suppressing undesired temperature rise is highlighted. Copyright © 2017 Elsevier Ltd. All rights reserved.

[Study of blood sedimentation by photo-thermal radiometry with random excitation].

PubMed

Antoniow, J S; Marx, J; Egee, M; Droulle, C; Potron, G

1994-01-01

The erythrocyte sedimentation rate is a complex phenomena involving a large number of parameters. The rate of sedimentation is highly dependent on the haematocrit, the internal viscosity of the red cells and the viscosity of the suspending medium and its composition. The experimental conditions also have a non-negligible effect (geometry and nature of the test tube, temperature, foreign substances in the medium...). In order to respond to the need for more precise and more rapid methods of analyzing the erythrocyte sedimentation rate, we developed new physical methods allowing a real time evaluation of the phenomena involved. Several of these new photothermal methods have already been applied for non-destructive evaluation of thin or layered material (such as composite material or glued structures) both in laboratory situations and in the industry. When a material is placed in a modulated laser beam, the incident rays absorbed heat the sample. The heat then diffuses throughout the material and the surface temperature of the sample increases locally with a periodicity. The surface thus emits a modulated flow of infrared radiation. The amplitude and phase shift of the photothermal signal generated is characteristically dependent of the optic and thermal properties of the material for a given modulation frequency. The early photothermal modelling based on a two-layer model and a physico-mathematical theory of red cell sedimentation proposed by S. Oka made it possible to simulate the phenomena as they occur over time. We hypothesize that the temperature gradients created within the sample are too small to create a convection current and that the all heat transfer occurs by conduction.(ABSTRACT TRUNCATED AT 250 WORDS)

the observation, simulation and evaluation of lake-air interaction process over a high altitude small lake on the Tibetan Plateau

NASA Astrophysics Data System (ADS)

Wang, Binbin; Ma, Yaoming; Ma, Weiqiang; Su, Bob

2017-04-01

Lakes are an important part of the landscape on the Tibetan Plateau. The area that contains most of the plateau lakes has been expanding in recent years, but the impact of lakes on lake-atmosphere energy and water interactions is poorly understood because of a lack of observational data and adequate modeling systems. Furthermore, Precise measurements of evaporation and understanding of the physical controls on turbulent heat flux over lakes at different time scales have fundamental significance for catchment-scale water balance analysis and local-scale climate modeling. To test the performance of lake-air turbulent exchange models over high-altitude lakes and to understanding the driving forces for turbulent heat flux and obtain the actual evaporation over the small high-altitude lakes, an eddy covariance observational system was built above the water surface of the small Nam Co Lake (with an altitude of 4715 m and an area of approximately 1 km2) in April 2012. Firstly, we proposed the proper Charnock coefficient (0.031) and the roughness Reynolds number (0.54) for simulation using turbulent data in 2012, and validated the results using data in 2013 independently; secondly, wind speed shows significance at half-hourly time scales, whereas water vapor and temperature gradients have higher correlations over daily and monthly time scales in lake-air turbulent heat exchange; thirdly, the total evaporation in this small lake (812 mm) is approximately 200 mm larger than that from adjacent Nam Co (approximately 627 mm) during their ice-free seasons. Moreover, the energy stored during April to June is mainly released during September to November, suggesting an energy balance closure value of 0.97 over the entire ice-free season; lastly, 10 evaporation estimation methods are evaluated with the prepared datasets.

Use of a liquid-crystal, heater-element composite for quantitative, high-resolution heat transfer coefficients on a turbine airfoil, including turbulence and surface roughness effects

NASA Astrophysics Data System (ADS)

Hippensteele, Steven A.; Russell, Louis M.; Torres, Felix J.

1987-05-01

Local heat transfer coefficients were measured along the midchord of a three-times-size turbine vane airfoil in a static cascade operated at roon temperature over a range of Reynolds numbers. The test surface consisted of a composite of commercially available materials: a Mylar sheet with a layer of cholestric liquid crystals, which change color with temperature, and a heater made of a polyester sheet coated with vapor-deposited gold, which produces uniform heat flux. After the initial selection and calibration of the composite sheet, accurate, quantitative, and continuous heat transfer coefficients were mapped over the airfoil surface. Tests were conducted at two free-stream turbulence intensities: 0.6 percent, which is typical of wind tunnels; and 10 percent, which is typical of real engine conditions. In addition to a smooth airfoil, the effects of local leading-edge sand roughness were also examined for a value greater than the critical roughness. The local heat transfer coefficients are presented for both free-stream turbulence intensities for inlet Reynolds numbers from 1.20 to 5.55 x 10 to the 5th power. Comparisons are also made with analytical values of heat transfer coefficients obtained from the STAN5 boundary layer code.

Use of a liquid-crystal and heater-element composite for quantitative, high-resolution heat-transfer coefficients on a turbine airfoil including turbulence and surface-roughness effects

NASA Astrophysics Data System (ADS)

Hippensteele, S. A.; Russell, L. M.; Torres, F. J.

Local heat transfer coefficients were measured along the midchord of a three-times-size turbine vane airfoil in a static cascade operated at room temperature over a range of Reynolds numbers. The test surface consisted of a composite of commercially available materials: a Mylar sheet with a layer of cholestric liquid crystals, which change color with temperature, and a heater made of a polyester sheet coated with vapor-deposited gold, which produces uniform heat flux. After the initial selection and calibration of the composite sheet, accurate, quantitative, and continuous heat transfer coefficients were mapped over the airfoil surface. Tests were conducted at two free-stream turbulence intensities: 0.6 percent, which is typical of wind tunnels; and 10 percent, which is typical of real engine conditions. In addition to a smooth airfoil, the effects of local leading-edge sand roughness were also examined for a value greater than the critical roughness. The local heat transfer coefficients are presented for both free-stream turbulence intensities for inlet Reynolds numbers from 1.20 to 5.55 x 10 to the 5th power. Comparisons are also made with analytical values of heat transfer coefficients obtained from the STAN5 boundary layer code.

Use of a liquid-crystal, heater-element composite for quantitative, high-resolution heat transfer coefficients on a turbine airfoil, including turbulence and surface roughness effects

NASA Technical Reports Server (NTRS)

Hippensteele, Steven A.; Russell, Louis M.; Torres, Felix J.

1987-01-01

Local heat transfer coefficients were measured along the midchord of a three-times-size turbine vane airfoil in a static cascade operated at roon temperature over a range of Reynolds numbers. The test surface consisted of a composite of commercially available materials: a Mylar sheet with a layer of cholestric liquid crystals, which change color with temperature, and a heater made of a polyester sheet coated with vapor-deposited gold, which produces uniform heat flux. After the initial selection and calibration of the composite sheet, accurate, quantitative, and continuous heat transfer coefficients were mapped over the airfoil surface. Tests were conducted at two free-stream turbulence intensities: 0.6 percent, which is typical of wind tunnels; and 10 percent, which is typical of real engine conditions. In addition to a smooth airfoil, the effects of local leading-edge sand roughness were also examined for a value greater than the critical roughness. The local heat transfer coefficients are presented for both free-stream turbulence intensities for inlet Reynolds numbers from 1.20 to 5.55 x 10 to the 5th power. Comparisons are also made with analytical values of heat transfer coefficients obtained from the STAN5 boundary layer code.

Local measurement and numerical modeling of mass/heat transfer from a turbine blade in a linear cascade with tip clearance

NASA Astrophysics Data System (ADS)

Jin, Peitong

2000-11-01

Local mass/heat transfer measurements from the turbine blade near-tip and the tip surfaces are performed using the naphthalene sublimation technique. The experiments are conducted in a linear cascade consisting of five high-pressure blades with a central test-blade configuration. The incoming flow conditions are close to those of the gas turbine engine environment (boundary layer displacement thickness is about 0.01 of chord) with an exit Reynolds number of 6.2 x 105. The effects of tip clearance level (0.86%--6.90% of chord), mainstream Reynolds number and turbulence intensity (0.2 and 12.0%) are investigated. Two methods of flow visualization---oil and lampblack, laser light sheet smoke wire---as well as static pressure measurement on the blade surface are used to study the tip leakage flow and vortex in the cascade. In addition, numerical modeling of the flow and heat transfer processes in the linear cascade with different tip clearances is conducted using commercial software incorporating advanced turbulence models. The present study confirms many important results on the tip leakage flow and vortex from the literature, contributes to the current understanding in the effects of tip leakage flow and vortex on local heat transfer from the blade near-tip and the tip surfaces, and provides detailed local and average heat/mass transfer data applicable to turbine blade tip cooling design.

Heat Transfer Enhancement for Finned-Tube Heat Exchangers with Vortex Generators: Experimental and Numerical Results

DOE Office of Scientific and Technical Information (OSTI.GOV)

O'Brien, James Edward; Sohal, Manohar Singh; Huff, George Albert

2002-08-01

A combined experimental and numerical investigation is under way to investigate heat transfer enhancement techniques that may be applicable to large-scale air-cooled condensers such as those used in geothermal power applications. The research is focused on whether air-side heat transfer can be improved through the use of finsurface vortex generators (winglets,) while maintaining low heat exchanger pressure drop. A transient heat transfer visualization and measurement technique has been employed in order to obtain detailed distributions of local heat transfer coefficients on model fin surfaces. Pressure drop measurements have also been acquired in a separate multiple-tube row apparatus. In addition, numericalmore » modeling techniques have been developed to allow prediction of local and average heat transfer for these low-Reynolds-number flows with and without winglets. Representative experimental and numerical results presented in this paper reveal quantitative details of local fin-surface heat transfer in the vicinity of a circular tube with a single delta winglet pair downstream of the cylinder. The winglets were triangular (delta) with a 1:2 height/length aspect ratio and a height equal to 90% of the channel height. Overall mean fin-surface Nusselt-number results indicate a significant level of heat transfer enhancement (average enhancement ratio 35%) associated with the deployment of the winglets with oval tubes. Pressure drop measurements have also been obtained for a variety of tube and winglet configurations using a single-channel flow apparatus that includes four tube rows in a staggered array. Comparisons of heat transfer and pressure drop results for the elliptical tube versus a circular tube with and without winglets are provided. Heat transfer and pressure-drop results have been obtained for flow Reynolds numbers based on channel height and mean flow velocity ranging from 700 to 6500.« less

Precision optical slit for high heat load or ultra high vacuum

DOEpatents

Andresen, N.C.; DiGennaro, R.S.; Swain, T.L.

1995-01-24

This invention relates generally to slits used in optics that must be precisely aligned and adjusted. The optical slits of the present invention are useful in x-ray optics, x-ray beam lines, optical systems in which the entrance slit is critical for high wavelength resolution. The invention is particularly useful in ultra high vacuum systems where lubricants are difficult to use and designs which avoid the movement of metal parts against one another are important, such as monochromators for high wavelength resolution with ultra high vacuum systems. The invention further relates to optical systems in which temperature characteristics of the slit materials is important. The present invention yet additionally relates to precision slits wherein the opposing edges of the slit must be precisely moved relative to a center line between the edges with each edge retaining its parallel orientation with respect to the other edge and/or the center line. 21 figures.

Precision optical slit for high heat load or ultra high vacuum

DOEpatents

Andresen, Nord C.; DiGennaro, Richard S.; Swain, Thomas L.

1995-01-01

This invention relates generally to slits used in optics that must be precisely aligned and adjusted. The optical slits of the present invention are useful in x-ray optics, x-ray beam lines, optical systems in which the entrance slit is critical for high wavelength resolution. The invention is particularly useful in ultra high vacuum systems where lubricants are difficult to use and designs which avoid the movement of metal parts against one another are important, such as monochrometers for high wavelength resolution with ultra high vacuum systems. The invention further relates to optical systems in which temperature characteristics of the slit materials is important. The present invention yet additionally relates to precision slits wherein the opposing edges of the slit must be precisely moved relative to a center line between the edges with each edge retaining its parallel orientation with respect to the other edge and/or the center line.

Intratumoral iron oxide nanoparticle hyperthermia and radiation cancer treatment

NASA Astrophysics Data System (ADS)

Hoopes, P. J.; Strawbridge, R. R.; Gibson, U. J.; Zeng, Q.; Pierce, Z. E.; Savellano, M.; Tate, J. A.; Ogden, J. A.; Baker, I.; Ivkov, R.; Foreman, A. R.

2007-02-01

The potential synergism and benefit of combined hyperthermia and radiation for cancer treatment is well established, but has yet to be optimized clinically. Specifically, the delivery of heat via external arrays /applicators or interstitial antennas has not demonstrated the spatial precision or specificity necessary to achieve appropriate a highly positive therapeutic ratio. Recently, antibody directed and possibly even non-antibody directed iron oxide nanoparticle hyperthermia has shown significant promise as a tumor treatment modality. Our studies are designed to determine the effects (safety and efficacy) of iron oxide nanoparticle hyperthermia and external beam radiation in a murine breast cancer model. Methods: MTG-B murine breast cancer cells (1 x 106) were implanted subcutaneous in 7 week-old female C3H/HeJ mice and grown to a treatment size of 150 mm3 +/- 50 mm3. Tumors were then injected locally with iron oxide nanoparticles and heated via an alternating magnetic field (AMF) generator operated at approximately 160 kHz and 400 - 550 Oe. Tumor growth was monitored daily using standard 3-D caliper measurement technique and formula. specific Mouse tumors were heated using a cooled, 36 mm diameter square copper tube induction coil which provided optimal heating in a 1 cm wide region in the center of the coil. Double dextran coated 80 nm iron oxide nanoparticles (Triton Biosystems) were used in all studies. Intra-tumor, peri-tumor and rectal (core body) temperatures were continually measured throughout the treatment period. Results: Preliminary in vivo nanoparticle-AMF hyperthermia (167 KHz and 400 or 550 Oe) studies demonstrated dose responsive cytotoxicity which enhanced the effects of external beam radiation. AMF associated eddy currents resulted in nonspecific temperature increases in exposed tissues which did not contain nanoparticles, however these effects were minor and not injurious to the mice. These studies also suggest that iron oxide nanoparticle hyperthermia is more effective than non-nanoparticle tumor heating techniques when similar thermal doses are applied. Initial electron and light microscopy studies of iron oxide nanoparticle and AMF exposed tumor cells show a rapid uptake of particles and acute cytotoxicity following AMF exposure.

Partial discharge localization in power transformers based on the sequential quadratic programming-genetic algorithm adopting acoustic emission techniques

NASA Astrophysics Data System (ADS)

Liu, Hua-Long; Liu, Hua-Dong

2014-10-01

Partial discharge (PD) in power transformers is one of the prime reasons resulting in insulation degradation and power faults. Hence, it is of great importance to study the techniques of the detection and localization of PD in theory and practice. The detection and localization of PD employing acoustic emission (AE) techniques, as a kind of non-destructive testing, plus due to the advantages of powerful capability of locating and high precision, have been paid more and more attention. The localization algorithm is the key factor to decide the localization accuracy in AE localization of PD. Many kinds of localization algorithms exist for the PD source localization adopting AE techniques including intelligent and non-intelligent algorithms. However, the existed algorithms possess some defects such as the premature convergence phenomenon, poor local optimization ability and unsuitability for the field applications. To overcome the poor local optimization ability and easily caused premature convergence phenomenon of the fundamental genetic algorithm (GA), a new kind of improved GA is proposed, namely the sequence quadratic programming-genetic algorithm (SQP-GA). For the hybrid optimization algorithm, SQP-GA, the sequence quadratic programming (SQP) algorithm which is used as a basic operator is integrated into the fundamental GA, so the local searching ability of the fundamental GA is improved effectively and the premature convergence phenomenon is overcome. Experimental results of the numerical simulations of benchmark functions show that the hybrid optimization algorithm, SQP-GA, is better than the fundamental GA in the convergence speed and optimization precision, and the proposed algorithm in this paper has outstanding optimization effect. At the same time, the presented SQP-GA in the paper is applied to solve the ultrasonic localization problem of PD in transformers, then the ultrasonic localization method of PD in transformers based on the SQP-GA is proposed. And localization results based on the SQP-GA are compared with some algorithms such as the GA, some other intelligent and non-intelligent algorithms. The results of calculating examples both stimulated and spot experiments demonstrate that the localization method based on the SQP-GA can effectively prevent the results from getting trapped into the local optimum values, and the localization method is of great feasibility and very suitable for the field applications, and the precision of localization is enhanced, and the effectiveness of localization is ideal and satisfactory.

Rubber friction: role of the flash temperature

NASA Astrophysics Data System (ADS)

Persson, B. N. J.

2006-08-01

When a rubber block is sliding on a hard rough substrate, the substrate asperities will exert time-dependent deformations of the rubber surface resulting in viscoelastic energy dissipation in the rubber, which gives a contribution to the sliding friction. Most surfaces of solids have roughness on many different length scales, and when calculating the friction force it is necessary to include the viscoelastic deformations on all length scales. The energy dissipation will result in local heating of the rubber. Since the viscoelastic properties of rubber-like materials are extremely strongly temperature dependent, it is necessary to include the local temperature increase in the analysis. At very low sliding velocity the temperature increase is negligible because of heat diffusion, but already for velocities of order 10-2 m s-1 the local heating may be very important. Here I study the influence of the local heating on the rubber friction, and I show that in a typical case the temperature increase results in a decrease in rubber friction with increasing sliding velocity for v>0.01 m s-1. This may result in stick-slip instabilities, and is of crucial importance in many practical applications, e.g. for tyre-road friction and in particular for ABS braking systems.

Heat Pipes Cool Power Magnetics

NASA Technical Reports Server (NTRS)

Hansen, I.; Chester, M.; Luedke, E.

1983-01-01

Configurations originally developed for space use are effective in any orientation. Heat pipes integrated into high-power, high-frequency, highvoltage spaceflight magnetics reduce weight and improve reliability by lowering internal tempertures. Two heat pipes integrated in design of power transformer cool unit in any orientation. Electrostatic shield conducts heat from windings to heat pipe evaporator. Technology allows dramatic reductions in size and weight, while significantly improving reliability. In addition, all attitude design of heat pipes allows operation of heat pipes independent of local gravity forces.

Hydrophobic Light-to-Heat Conversion Membranes with Self-Healing Ability for Interfacial Solar Heating.

PubMed

Zhang, Lianbin; Tang, Bo; Wu, Jinbo; Li, Renyuan; Wang, Peng

2015-09-02

Self-healing hydrophobic light-to-heat conversion membranes for interfacial solar heating are fabricated by deposition of light-to-heat conversion material of polypyrrole onto a porous stainless-steel mesh, followed by hydrophobic fluoroalkylsilane modification. The mesh-based membranes spontaneously stay at the water-air interface, collect and convert solar light into heat, and locally heat only the water surface for enhanced evaporation. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Local heat transfer in turbine disk-cavities. I - Rotor and stator cooling with hub injection of coolant

NASA Astrophysics Data System (ADS)

Bunker, R. S.; Metzger, D. E.; Wittig, S.

1990-06-01

Detailed radial heat-transfer coefficient distributions applicable to the cooling of disk-cavity regions of gas turbines are obtained experimentally from local heat-transfer data on both the rotating and stationary surfaces of a parallel-geometry disk-cavity system. Attention is focused on the hub injection of a coolant over a wide range of parameters including disk rotational Reynolds numbers of 200,000 to 50,000, rotor/stator spacing-to-disk ratios of 0.025 to 0.15, and jet mass flow rates between 0.10 and 0.40 times the turbulent pumped flow rate of a free disk. It is shown that rotor heat transfer exhibits regions of impingement and rotational domination with a transition region between, while stator heat transfer displays flow reattachment and convection regions with an inner recirculation zone.

Resonance fluorescence microscopy via three-dimensional atom localization

NASA Astrophysics Data System (ADS)

Panchadhyayee, Pradipta; Dutta, Bibhas Kumar; Das, Nityananda; Mahapatra, Prasanta Kumar

2018-02-01

A scheme is proposed to realize three-dimensional (3D) atom localization in a driven two-level atomic system via resonance fluorescence. The field arrangement for the atom localization involves the application of three mutually orthogonal standing-wave fields and an additional traveling-wave coupling field. We have shown the efficacy of such field arrangement in tuning the spatially modulated resonance in all directions. Under different parametric conditions, the 3D localization patterns originate with various shapes such as sphere, sheets, disk, bowling pin, snake flute, flower vase. High-precision localization is achieved when the radiation field detuning equals twice the combined Rabi frequencies of the standing-wave fields. Application of a traveling-wave field of suitable amplitude at optimum radiation field detuning under symmetric standing-wave configuration leads to 100% detection probability even in sub-wavelength domain. Asymmetric field configuration is also taken into consideration to exhibit atom localization with appreciable precision compared to that of the symmetric case. The momentum distribution of the localized atoms is found to follow the Heisenberg uncertainty principle under the validity of Raman-Nath approximation. The proposed field configuration is suitable for application in the study of atom localization in an optical lattice arrangement.

Heat shock modulates the subcellular localization, stability, and activity of HIPK2

DOE Office of Scientific and Technical Information (OSTI.GOV)

Upadhyay, Mamta; Bhadauriya, Pratibha; Ganesh, Subramaniam, E-mail: sganesh@iitk.ac.in

2016-04-15

The homeodomain-interacting protein kinase-2 (HIPK2) is a highly conserved serine/threonine kinase and is involved in transcriptional regulation. HIPK2 is a highly unstable protein, and is kept at a low level under normal physiological conditions. However, exposure of cells to physiological stress – such as hypoxia, oxidative stress, or UV damage – is known to stabilize HIPK2, leading to the HIPK2-dependent activation of p53 and the cell death pathway. Therefore HIPK2 is also known as a stress kinase and as a stress-activated pro-apoptotic factor. We demonstrate here that exposure of cells to heat shock results in the stabilization of HIPK2 andmore » the stabilization is mediated via K63-linked ubiquitination. Intriguingly, a sub-lethal heat shock (42 °C, 1 h) results in the cytoplasmic localization of HIPK2, while a lethal heat shock (45 °C, 1 h) results in its nuclear localization. Cells exposed to the lethal heat shock showed significantly higher levels of the p53 activity than those exposed to the sub-lethal thermal stress, suggesting that both the level and the nuclear localization are essential for the pro-apoptotic activity of HIPK2 and that the lethal heat shock could retain the HIPK2 in the nucleus to promote the cell death. Taken together our study underscores the importance of HIPK2 in stress mediated cell death, and that the HIPK2 is a generic stress kinase that gets activated by diverse set of physiological stressors.« less

Contributions Regarding the Aircraft Nuclear Propulsion

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mitrica, Bogdan; Petre, Marian; Dima, Mihai Octavian

2010-01-21

The possibility to use a nuclear reactor for airplanes propulsion was investigated taking in to account 2 possible solutions: the direct cycle (where the fluid pass through the reactor's core) and the indirect cycle (where the fluid is passing through a heat exchanger). Taking in to account the radioprotection problems, the only realistic solution seems to be the indirect cycle, where the energy transfer should be performed by a heat exchanger that must work at very high speed of the fluid. The heat exchanger will replace the classical burning room. We had performed a more precise theoretical study for themore » nuclear jet engine regarding the performances of the nuclear reactor, of the heat exchanger and of the jet engine. It was taken in to account that in the moment when the burning room is replaced by a heat exchanger, a new model for gasodynamic process from the engine must be performed. Studies regarding the high flow speed heat transfer were performed.« less

Electroosmotic flow and Joule heating in preparative continuous annular electrochromatography.

PubMed

Laskowski, René; Bart, Hans-Jörg

2015-09-01

An openFOAM "computational fluid dynamic" simulation model was developed for the description of local interaction of hydrodynamics and Joule heating in annular electrochromatography. A local decline of electrical conductivity of the background eluent is caused by an electrokinetic migration of ions resulting in higher Joule heat generation. The model equations consider the Navier-Stokes equation for incompressible fluids, the energy equation for stationary temperature fields, and the mass transfer equation for the electrokinetic flow. The simulations were embedded in commercial ANSYS Fluent software and in open-source environment openFOAM. The annular gap (1 mm width) contained an inorganic C8 reverse-phase monolith as stationary phase prepared by an in situ sol-gel process. The process temperature generated by Joule heating was determined by thermal camera system. The local hydrodynamics in the prototype was detected by a gravimetric contact-free measurement method and experimental and simulated values matched quite well. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Regressed relations for forced convection heat transfer in a direct injection stratified charge rotary engine

NASA Technical Reports Server (NTRS)

Lee, Chi M.; Schock, Harold J.

1988-01-01

Currently, the heat transfer equation used in the rotary combustion engine (RCE) simulation model is taken from piston engine studies. These relations have been empirically developed by the experimental input coming from piston engines whose geometry differs considerably from that of the RCE. The objective of this work was to derive equations to estimate heat transfer coefficients in the combustion chamber of an RCE. This was accomplished by making detailed temperature and pressure measurements in a direct injection stratified charge (DISC) RCE under a range of conditions. For each specific measurement point, the local gas velocity was assumed equal to the local rotor tip speed. Local physical properties of the fluids were then calculated. Two types of correlation equations were derived and are described in this paper. The first correlation expresses the Nusselt number as a function of the Prandtl number, Reynolds number, and characteristic temperature ratio; the second correlation expresses the forced convection heat transfer coefficient as a function of fluid temperature, pressure and velocity.

Localized, plasmon-mediated heating from embedded nanoparticles in nanocomposites

NASA Astrophysics Data System (ADS)

Maity, Somsubhra; Downen, Lori; Bochinski, Jason; Clarke, Laura

2010-03-01

Metallic nanoparticles exhibit a surface plasmon resonance which, when excited with visible light, results in a dramatic increase in the nanoparticle temperature. Previously such localized heating has been primarily employed in biomedical research and other experiments involving aqueous environments. In this work, we investigated use of the nanoparticles in solid phase to re-shape, bond, melt, and otherwise process nanofibrous mats of ˜200 nm diameter nanofibers doped with ˜80 nm spherical gold nanoparticles. Under low light intensities (100 mW/cm^2 @ 532 nm) and dilute nanoparticle loading (˜0.15% volume fraction), irradiation of a few minutes melted nanofibrous mats of poly (ethylene oxide) (Tm = 65 degree C). Control samples without gold nanoparticles displayed no melting. Because the heat is generated from within the material and only at the nanoparticle locations, this technique enables true nanoprocessing -- the non-contact, controlled application of heat at specific nano-sized locations within a material to effect desired local changes. Funded by CMMI-0829379.

Effect of radiation and magnetohydrodynamic free convection boundary layer flow on a solid sphere with Newtonian heating in a micropolar fluid

DOE Office of Scientific and Technical Information (OSTI.GOV)

Alkasasbeh, Hamzeh Taha, E-mail: zukikuj@yahoo.com; Sarif, Norhafizah Md, E-mail: zukikuj@yahoo.com; Salleh, Mohd Zuki, E-mail: zukikuj@yahoo.com

2015-02-03

In this paper, the effect of radiation on magnetohydrodynamic free convection boundary layer flow on a solid sphere with Newtonian heating in a micropolar fluid, in which the heat transfer from the surface is proportional to the local surface temperature, is considered. The transformed boundary layer equations in the form of nonlinear partial differential equations are solved numerically using an implicit finite difference scheme known as the Keller-box method. Numerical solutions are obtained for the local wall temperature and the local skin friction coefficient, as well as the velocity, angular velocity and temperature profiles. The features of the flow andmore » heat transfer characteristics for various values of the Prandtl number Pr, micropolar parameter K, magnetic parameter M, radiation parameter N{sub R}, the conjugate parameter γ and the coordinate running along the surface of the sphere, x are analyzed and discussed.« less

22 CFR 228.40 - Local procurement.

Code of Federal Regulations, 2010 CFR

2010-04-01

... transaction does not exceed $5,000. (c) Professional services contracts estimated not to exceed the local... available locally: (1) Utilities, including fuel for heating and cooking, waste disposal and trash...

Impact of different thickness of the smooth heated surface on flow boiling heat transfer

NASA Astrophysics Data System (ADS)

Strąk, Kinga; Piasecka, Magdalena

2018-06-01

This paper presents a comparison of the performance of three smooth heated surfaces with different thicknesses. Analysis was carried out on an experimental setup for flow boiling heat transfer. The most important element of the setup was the test section with a rectangular minichannel, 1.7 mm deep, 16 mm wide and 180 mm long, oriented vertically. The heated element for the FC-72 Fluorinert flowing in the minichannel was designated as a Haynes-230 alloy plate (0.10 mm and 0.45 mm thick) or a Hastelloy X alloy plate (0.65 mm thick). Infrared thermography was used to measure the temperature of the outer plate surface. The local values of the heat transfer coefficient for stationary state conditions were calculated using a simple one-dimensional method. The experimental results were presented as the relationship between the heat transfer coefficients in the subcooled boiling region and the distance along the minichannel length and boiling curves. The highest local heat transfer coefficients were recorded for the surface of 0.10 mm thick heated plate at the outlet and 0.45 mm thick plate at the minichannel inlet. All boiling curves were typical in shape.

Development of Precision Pointing Controllers with and Without Vibration Suppression for the NPS Precision Pointing Hexapod

DTIC Science & Technology

2002-12-01

applications, vibration sources are numerous such as: ! Launch Loading ! Man-induced accelerations like on the Shuttle or space station ! Solar ...However, the lack of significant tracking errors during times when other actuators were stationary, and the fact that the local maximum tracking...

Role of thermal heating on the voltage induced insulator-metal transition in VO2.

PubMed

Zimmers, A; Aigouy, L; Mortier, M; Sharoni, A; Wang, Siming; West, K G; Ramirez, J G; Schuller, Ivan K

2013-02-01

We show that the main mechanism for the dc voltage or dc current induced insulator-metal transition in vanadium dioxide VO(2) is due to local Joule heating and not a purely electronic effect. This "tour de force" experiment was accomplished by using the fluorescence spectra of rare-earth doped micron sized particles as local temperature sensors. As the insulator-metal transition is induced by a dc voltage or dc current, the local temperature reaches the transition temperature indicating that Joule heating plays a predominant role. This has critical implications for the understanding of the dc voltage or dc current induced insulator-metal transition and has a direct impact on applications which use dc voltage or dc current to externally drive the transition.

Local melting in Al embedded with TiNi powder induced by microarea self-propagating high-temperature synthesis

NASA Astrophysics Data System (ADS)

Yamamoto, Tokujiro

2014-10-01

Microarea self-propagating high-temperature synthesis (microSHS) was ignited by the heat of mixing generated at the boundaries between an Al matrix and TiNi particles during plastic deformation at room temperature. The temperature of the boundaries was rapidly increased by microSHS; the temperature elevation resulted in local melting of the TiNi particle and the surrounding Al matrix, because the heat of mixing was localized in the vicinity of the TiNi particle although the amount of the heat of mixing was limited. Since the amount of the local melting region induced by microSHS is restricted, not only major elements (i.e. Al, Ti and Ni) but also impurities were involved in the solidification followed by local melting. As a result, ?FeNi nanoprecipitates, which have not been reported in SHS studies, were formed by inclusion of Fe, initially included as an impurity in raw materials. The formation mechanism of ?FeNi nanoprecipitates is discussed based on reference to the Al-Fe-Ni ternary alloy phase diagram. It is expected that local melting induced by microSHS is a key phenomonon for amorphization during severe plastic deformation of elemental sheets.

Precision of DVC approaches for strain analysis in bone imaged with μCT at different dimensional levels.

NASA Astrophysics Data System (ADS)

Dall'Ara, Enrico; Peña-Fernández, Marta; Palanca, Marco; Giorgi, Mario; Cristofolini, Luca; Tozzi, Gianluca

2017-11-01

Accurate measurement of local strain in heterogeneous and anisotropic bone tissue is fundamental to understand the pathophysiology of musculoskeletal diseases, to evaluate the effect of interventions from preclinical studies, and to optimize the design and delivery of biomaterials. Digital volume correlation (DVC) can be used to measure the three-dimensional displacement and strain fields from micro-Computed Tomography (µCT) images of loaded specimens. However, this approach is affected by the quality of the input images, by the morphology and density of the tissue under investigation, by the correlation scheme, and by the operational parameters used in the computation. Therefore, for each application the precision of the method should be evaluated. In this paper we present the results collected from datasets analyzed in previous studies as well as new data from a recent experimental campaign for characterizing the relationship between the precision of two different DVC approaches and the spatial resolution of the outputs. Different bone structures scanned with laboratory source µCT or Synchrotron light µCT (SRµCT) were processed in zero-strain tests to evaluate the precision of the DVC methods as a function of the subvolume size that ranged from 8 to 2500 micrometers. The results confirmed that for every microstructure the precision of DVC improves for larger subvolume size, following power laws. However, for the first time large differences in the precision of both local and global DVC approaches have been highlighted when SRµCT or in vivo µCT images were used instead of conventional ex vivo µCT. These findings suggest that in situ mechanical testing protocols applied in SRµCT facilities should be optimized in order to allow DVC analyses of localized strain measurements. Moreover, for in vivo µCT applications DVC analyses should be performed only with relatively course spatial resolution for achieving a reasonable precision of the method. In conclusion, we have extensively shown that the precision of both tested DVC approaches is affected by different bone structures, different input image resolution and different subvolume sizes. Before each specific application DVC users should always apply a similar approach to find the best compromise between precision and spatial resolution of the measurements.

Extreme learning machine: a new alternative for measuring heat collection rate and heat loss coefficient of water-in-glass evacuated tube solar water heaters.

PubMed

Liu, Zhijian; Li, Hao; Tang, Xindong; Zhang, Xinyu; Lin, Fan; Cheng, Kewei

2016-01-01

Heat collection rate and heat loss coefficient are crucial indicators 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, wasting too much time and manpower. To address this problem, we previously used artificial neural networks and support vector machine to develop precise knowledge-based models for predicting the heat collection rates and heat loss coefficients of water-in-glass evacuated tube solar water heaters, setting the properties measured by "portable test instruments" as the independent variables. A robust software for determination was also developed. However, in previous results, the prediction accuracy of heat loss coefficients can still be improved compared to those of heat collection rates. Also, in practical applications, even a small reduction in root mean square errors (RMSEs) can sometimes significantly improve the evaluation and business processes. As a further study, in this short report, we show that using a novel and fast machine learning algorithm-extreme learning machine can generate better predicted results for heat loss coefficient, which reduces the average RMSEs to 0.67 in testing.

Cargo systems manual: Heat Pipe Performance (HPP) STS-66

NASA Technical Reports Server (NTRS)

Napp, Robert

1994-01-01

The purpose of the cargo systems manual (CSM) is to provide a payload reference document for payload and shuttle flight operations personnel during shuttle mission planning, training, and flight operations. It includes orbiter-to-payload interface information and payload system information (including operationally pertinent payload safety data) that is directly applicable to the Mission Operations Directorate (MOD) role in the payload mission. The primary objectives of the heat pipe performance (HPP) are to obtain quantitative data on the thermal performance of heat pipes in a microgravity environment. This information will increase understanding of the behavior of heat pipes in space and be useful for application to design improvements in heat pipes and associated systems. The purpose of HPP-2 is to establish a complete one-g and zero-g data base for axial groove heat pipes. This data will be used to update and correlate data generated from a heat pipe design computer program called Grooved Analysis Program (GAP). The HPP-2 objectives are to: determine heat transport capacity and conductance for open/closed grooved heat pipes and different Freon volumes (nominal, under, and overcharged) using a uniform heat load; determine heat transport capacity and conductance for single/multiple evaporators using asymmetric heat loads; obtain precise static, spin, and rewicking data points for undercharged pipes; investigate heat flux limits (asymmetric heat loads); and determine effects of positive body force on thermal performance.

Localized Electron Heating by Strong Guide-Field Magnetic Reconnection

NASA Astrophysics Data System (ADS)

Guo, Xuehan; Sugawara, Takumichi; Inomoto, Michiaki; Yamasaki, Kotaro; Ono, Yasushi; UTST Team

2015-11-01

Localized electron heating of magnetic reconnection was studied under strong guide-field (typically Bt 15Bp) using two merging spherical tokamak plasmas in Univ. Tokyo Spherical Tokamak (UTST) experiment. Our new slide-type two-dimensional Thomson scattering system documented for the first time the electron heating localized around the X-point. The region of high electron temperature, which is perpendicular to the magnetic field, was found to have a round shape with radius of 2 [cm]. Also, it was localized around the X-point and does not agree with that of energy dissipation term Et .jt . When we include a guide-field effect term Bt / (Bp + αBt) for Et .jt where α =√{ (vin2 +vout2) /v∥2 } , the energy dissipation area becomes localized around the X-point, suggesting that the electrons are accelerated by the reconnection electric field parallel to the magnetic field and thermalized around the X-point. This work was supported by JSPS A3 Foresight Program ``Innovative Tokamak Plasma Startup and Current Drive in Spherical Torus,'' a Grant-in-Aid from the Japan Society for the Promotion of Science (JSPS) Fellows 15J03758.

Heat-Energy Analysis for Solar Receivers

NASA Technical Reports Server (NTRS)

Lansing, F. L.

1982-01-01

Heat-energy analysis program (HEAP) solves general heat-transfer problems, with some specific features that are "custom made" for analyzing solar receivers. Can be utilized not only to predict receiver performance under varying solar flux, ambient temperature and local heat-transfer rates but also to detect locations of hotspots and metallurgical difficulties and to predict performance sensitivity of neighboring component parameters.

Comparison of Total Evaporation (TE) and Direct Total Evaporation (DTE) methods in TIMS by using NBL CRMs

NASA Astrophysics Data System (ADS)

Hasözbek, Altug; Mathew, Kattathu; Wegener, Michael

2013-04-01

The total evaporation (TE) is a well-established analytical method for safeguards measurement of uranium and plutonium isotope-amount ratios using the thermal ionization mass spectrometry (TIMS). High accuracy and precision isotopic measurements find many applications in nuclear safeguards, for e.g. assay measurements using isotope dilution mass spectrometry. To achieve high accuracy and precision in TIMS measurements, mass dependent fractionation effects are minimized by either the measurement technique or changes in the hardware components that are used to control sample heating and evaporation process. At NBL, direct total evaporation (DTE) method on the modified MAT261 instrument, uses the data system to read the ion signal intensity and its difference from a pre-determined target intensity, is used to control the incremental step at which the evaporation filament is heated. The feedback and control is achieved by proprietary hardware from SPECTROMAT that uses an analog regulator in the filament power supply with direct feedback of the detector intensity. Compared to traditional TE method on this instrument, DTE provides better precision (relative standard deviation, expressed as a percent) and accuracy (relative difference, expressed as a percent) of 0.05 to 0.08 % for low enriched and high enriched NBL uranium certified reference materials.

Heat convection in a micro impinging jet system

NASA Astrophysics Data System (ADS)

Mai, John Dzung Hoang

2000-10-01

This thesis covers the development of an efficient micro impinging jet heat exchanger, using MEMS technology, to provide localized cooling for present and next generation microelectronic computer chips. Before designing an efficient localized heat exchanger, it is necessary to investigate fluid dynamics and heat transfer in the micro scale. MEMS technology has been used in this project because it is the only tool currently available that can provide a large array of batch-fabricated, micro-scale nozzles for localized cooling. Our investigation of potential MEMS heat exchanger designs begins with experiments that measure the pressure drops and temperature changes in a micro scale tubing system that will be necessary to carry fluid to the impingement point. Our basic MEMS model is a freestanding micro channel with integrated temperature microsensors. The temperature distribution along the channel in a vacuum is measured. The measured flow rates are compared with an analytical model developed for capillary flow that accounts for 2-D, slip and compressibility effects. The work is focused on obtaining correlations in the form of the Nussult number, the Reynolds number and a H/d geometric factor. A set of single MEMS nozzles have been designed to test heat transfer effectiveness as a function of nozzle diameter, ranging from 1.0 mm to 250 um. In addition, nozzle and slot array MEMS devices have been fabricated. In order to obtain quantitative measurements from these micron scale devices, a series of target temperature sensor chips were custom made and characterized for these experiments. The heat transfer characteristics of various MEMS nozzle configurations operating at various steady inlet pressures, at different heights above the heated substrate, have been characterized. These steady results showed that the average heat transfer coefficient, averaged over a 1 cm2 test area, was usually less than 0.035 W/cm 2K for any situation. However, the local heat transfer coefficient, as measured by a single 4mum x 4mum temperature sensor, was as high as 0.5 W/cm2K. Using a mechanical valve and piezo actuator to perturb the flow at frequencies from 10 Hz to 1 kHz, we identify that enhanced heat transfer can occur in an unsteady forced jet. The functional dependence of the enhanced heat transfer on the mean jet speed, perturbation level and perturbing frequency has been established. The expected trend that increased heat transfer at higher values of St number was noticed. In addition the effect of a confined and free jet geometry on an unsteady flow was observed.

Advanced Coupled Simulation of Borehole Thermal Energy Storage Systems and Above Ground Installations

NASA Astrophysics Data System (ADS)

Welsch, Bastian; Rühaak, Wolfram; Schulte, Daniel O.; Bär, Kristian; Sass, Ingo

2016-04-01

Seasonal thermal energy storage in borehole heat exchanger arrays is a promising technology to reduce primary energy consumption and carbon dioxide emissions. These systems usually consist of several subsystems like the heat source (e.g. solarthermics or a combined heat and power plant), the heat consumer (e.g. a heating system), diurnal storages (i.e. water tanks), the borehole thermal energy storage, additional heat sources for peak load coverage (e.g. a heat pump or a gas boiler) and the distribution network. For the design of an integrated system, numerical simulations of all subsystems are imperative. A separate simulation of the borehole energy storage is well-established but represents a simplification. In reality, the subsystems interact with each other. The fluid temperatures of the heat generation system, the heating system and the underground storage are interdependent and affect the performance of each subsystem. To take into account these interdependencies, we coupled a software for the simulation of the above ground facilities with a finite element software for the modeling of the heat flow in the subsurface and the borehole heat exchangers. This allows for a more realistic view on the entire system. Consequently, a finer adjustment of the system components and a more precise prognosis of the system's performance can be ensured.

Performance of a Heating Block System Designed for Studying the Heat Resistance of Bacteria in Foods

NASA Astrophysics Data System (ADS)

Kou, Xiao-Xi; Li, Rui; Hou, Li-Xia; Huang, Zhi; Ling, Bo; Wang, Shao-Jin

2016-07-01

Knowledge of bacteria’s heat resistance is essential for developing effective thermal treatments. Choosing an appropriate test method is important to accurately determine bacteria’s heat resistances. Although being a major factor to influence the thermo-tolerance of bacteria, the heating rate in samples cannot be controlled in water or oil bath methods due to main dependence on sample’s thermal properties. A heating block system (HBS) was designed to regulate the heating rates in liquid, semi-solid and solid foods using a temperature controller. Distilled water, apple juice, mashed potato, almond powder and beef were selected to evaluate the HBS’s performance by experiment and computer simulation. The results showed that the heating rates of 1, 5 and 10 °C/min with final set-point temperatures and holding times could be easily and precisely achieved in five selected food materials. A good agreement in sample central temperature profiles was obtained under various heating rates between experiment and simulation. The experimental and simulated results showed that the HBS could provide a sufficiently uniform heating environment in food samples. The effect of heating rate on bacterial thermal resistance was evaluated with the HBS. The system may hold potential applications for rapid and accurate assessments of bacteria’s thermo-tolerances.

Phase coherence of 0.1 Hz microvascular tone oscillations during the local heating

NASA Astrophysics Data System (ADS)

Mizeva, I. A.

2017-06-01

The origin of the mechanisms of blood flow oscillations at low frequencies is discussed. It is known that even isolated arteriole demonstrates oscillations with the frequency close to 0.1 Hz, which is caused by the synchronous activity of myocyte cells. On the other hand, oscillations with close frequency are found in the heart rate, which are associated with quite different mechanism. The main purpose of this work is to study phase coherence of the blood flow oscillations in the peripheral vessels under basal and perturbed conditions. Local heating which locally influences the microvascular tone, as one of currently elucidated in sufficient detail physiological test, was chosen. During such provocation blood flow though the small vessels significantly increases because of vasodilation induced by the local synthesis of nitric oxide. In the first part of the paper microvascular response to the local test is quantified in healthy and pathological conditions of diabetes mellitus type 1. It is obtained that regardless of the pathology, subjects with high basal perfusion had lower reserve for vasodilation, which can be caused by the low elasticity of microvascular structure. Further synchronization of pulsations of the heated and undisturbed skin was evaluated on the base of wavelet phase coherency analysis. Being highly synchronised in basal conditions 0.1 Hz pulsations became more independent during heating, especially during NO-mediated vasodilation.

Global climate change: impact of heat waves under different definitions on daily mortality in Wuhan, China.

PubMed

Zhang, Yunquan; Feng, Renjie; Wu, Ran; Zhong, Peirong; Tan, Xiaodong; Wu, Kai; Ma, Lu

2017-01-01

There was no consistent definition for heat wave worldwide, while a limited number of studies have compared the mortality effect of heat wave as defined differently. This paper aimed to provide epidemiological evidence for policy makers to determine the most appropriate definition for local heat wave warning systems. We developed 45 heat wave definitions (HWs) combining temperature indicators and temperature thresholds with durations. We then assessed the impact of heat waves under various definitions on non-accidental mortality in hot season (May-September) in Wuhan, China during 2003-2010. Heat waves defined by HW14 (daily mean temperature ≥ 99.0th percentile and duration ≥ 3 days) had the best predictive ability in assessing the mortality effects of heat wave with the relative risk of 1.63 (95% CI : 1.43, 1.89) for total mortality. The group-specific mortality risk using official heat wave definition of Chinese Meteorological Administration was much smaller than that using HW14. We also found that women, and the elderly (age ≥ 65) were more susceptible to heat wave effects which were stronger and longer lasting. These findings suggest that region specific heat wave definitions are crucial and necessary for developing efficient local heat warning systems and for providing evidence for policy makers to protect the vulnerable population.

A study of the flow boiling heat transfer in a minichannel for a heated wall with surface texture produced by vibration-assisted laser machining

NASA Astrophysics Data System (ADS)

Piasecka, Magdalena; Strąk, Kinga; Maciejewska, Beata; Grabas, Bogusław

2016-09-01

The paper presents results concerning flow boiling heat transfer in a vertical minichannel with a depth of 1.7 mm and a width of 16 mm. The element responsible for heating FC-72, which flowed laminarly in the minichannel, was a plate with an enhanced surface. Two types of surface textures were considered. Both were produced by vibration-assisted laser machining. Infrared thermography was used to record changes in the temperature on the outer smooth side of the plate. Two-phase flow patterns were observed through a glass pane. The main aim of the study was to analyze how the two types of surface textures affect the heat transfer coefficient. A two-dimensional heat transfer approach was proposed to determine the local values of the heat transfer coefficient. The inverse problem for the heated wall was solved using a semi-analytical method based on the Trefftz functions. The results are presented as relationships between the heat transfer coefficient and the distance along the minichannel length and as boiling curves. The experimental data obtained for the two types of enhanced heated surfaces was compared with the results recorded for the smooth heated surface. The highest local values of the heat transfer coefficient were reported in the saturated boiling region for the plate with the type 1 texture produced by vibration-assisted laser machining.

Local Equation of State for Protons, and Implications for Proton Heating in the Solar Wind.

NASA Astrophysics Data System (ADS)

Zaslavsky, A.; Maksimovic, M.; Kasper, J. C.

2017-12-01

The solar wind protons temperature is observed to decrease with distance to the Sun at a slower rate than expected from an adiabatic expansion law: the protons are therefore said to be heated. This observation raises the question of the evaluation of the heating rate, and the question of the heat source.These questions have been investigated by previous authors by gathering proton data on various distances to the Sun, using spacecraft as Helios or Ulysses, and then computing the radial derivative of the proton temperature in order to obtain a heating rate from the internal energy equation. The problem of such an approach is the computation of the radial derivative of the temperature profile, for which uncertainties are very large, given the dispersion of the temperatures measured at a given distance.An alternative approach, that we develop in this paper, consists in looking for an equation of state that links locally the pressure (or temperature) to the mass density. If such a relation exists then one can evaluate the proton heating rate on a local basis, without having any space derivative to compute.Here we use several years of STEREO and WIND proton data to search for polytropic equation of state. We show that such relationships are indeed a good approximation in given solar wind's velocity intervals and deduce the associated protons heating rates as a function of solar wind's speed. The obtained heating rates are shown to scale from around 1 kW/kg in the slow wind to around 10 kW/kg in the fast wind, in remarkable agreement with the rate of energy observed by previous authors to cascade in solar wind's MHD turbulence at 1 AU. These results therefore support the idea of proton turbulent heating in the solar wind.

The effect of near-surface heating on the underlying convection pattern with application to Enceladus

NASA Astrophysics Data System (ADS)

Roberts, J. H.; Nimmo, F.

2007-12-01

Rapid strike-slip motion is predicted to be a consequence of diurnal tidal stresses in most satellites of the outer solar system with short orbital timescales [1]. Such motion can lead to near-surface heating through friction or viscous dissipation [2]. Here we discuss the effect of near-surface shear heating on convection in the underlying ice shells of icy satellites [3], with a focus on Enceladus and a possible origin of the south polar thermal anomaly [4]. We present models of convection in spherical ice shells including both spatially variable volumetric tidal heating [5] and regional shear heating localized in the top 5 km at either the pole or the equator. We observe that the presence of the near-surface heating strongly controls the convective pattern, increasing the wavelength, and promoting the formation of a hot upwelling beneath the shear zone. Our results suggest that localized near- surface heating may result in a degree-1 convective planform in an ice shell of a thickness that may be appropriate for a differentiated Enceladus (d < 0.36 Rsat). The near-surface heating and convection pattern will produce a localized heat flow anomaly. The upwelling beneath the shear zone also produces a few hundred meters of long-wavelength dynamic topography. The ℓ=2 component of the topography may cause reorientation of the satellite [6]. [1] Hoppa, G., B. R. Tufts, R. Greenberg, and P. Geissler, Icarus, 141, 287-298, 1999. [2] Nimmo, F., E. Gaidos, JGR, 107, 5021, 2002. [3] Han, L., A. P. Showman, LPSC XXXVIII, #2277, 2007. [4] Spencer, J. R., et al., Science, 311, 1401-1405. [5] Tobie, G., A. Mocquet, C. Sotin, Icarus, 177 534-549. [6] Nimmo, F., R. T. Pappalardo, Nature, 441, 614-616.

A rapid decrease in temperature induces latewood formation in artificially reactivated cambium of conifer stems

PubMed Central

Begum, Shahanara; Nakaba, Satoshi; Yamagishi, Yusuke; Yamane, Kenichi; Islam, Md. Azharul; Oribe, Yuichiro; Ko, Jae-Heung; Jin, Hyun-O; Funada, Ryo

2012-01-01

Background and Aims Latewood formation in conifers occurs during the later part of the growing season, when the cell division activity of the cambium declines. Changes in temperature might be important for wood formation in trees. Therefore, the effects of a rapid decrease in temperature on cellular morphology of tracheids were investigated in localized heating-induced cambial reactivation in Cryptomeria japonica trees and in Abies firma seedlings. Methods Electric heating tape and heating ribbon were wrapped on the stems of C. japonica trees and A. firma seedlings. Heating was discontinued when 11 or 12 and eight or nine radial files of differentiating and differentiated tracheids had been produced in C. japonica and A. firma stems, respectively. Tracheid diameter, cell wall thickness, percentage of cell wall area and percentage of lumen area were determined by image analysis of transverse sections and scanning electron microscopy. Key Results Localized heating induced earlier cambial reactivation and xylem differentiation in stems of C. japonica and A. firma as compared with non-heated stems. One week after cessation of heating, there were no obvious changes in the dimensions of the differentiating tracheids in the samples from adult C. japonica. In contrast, tracheids with a smaller diameter were observed in A. firma seedlings after 1 week of cessation of heating. Two or three weeks after cessation of heating, tracheids with reduced diameters and thickened cell walls were found. The results showed that the rapid decrease in temperature produced slender tracheids with obvious thickening of cell walls that resembled latewood cells. Conclusions The results suggest that a localized decrease in temperature of stems induces changes in the diameter and cell wall thickness of differentiating tracheids, indicating that cambium and its derivatives can respond directly to changes in temperature. PMID:22843340

High temperature acoustic and hybrid microwave/acoustic levitators for materials processing

NASA Technical Reports Server (NTRS)

Barmatz, Martin

1990-01-01

The physical acoustics group at the Jet Propulsion Laboratory developed a single mode acoustic levitator technique for advanced containerless materials processing. The technique was successfully demonstrated in ground based studies to temperatures of about 1000 C in a uniform temperature furnace environment and to temperatures of about 1500 C using laser beams to locally heat the sample. Researchers are evaluating microwaves as a more efficient means than lasers for locally heating a positioned sample. Recent tests of a prototype single mode hybrid microwave/acoustic levitator successfully demonstrated the feasibility of using microwave power as a heating source. The potential advantages of combining acoustic positioning forces and microwave heating for containerless processing investigations are presented in outline form.

Numerical simulation of inertial alfven waves to study localized structures and spectral index in auroral region

NASA Astrophysics Data System (ADS)

Jatav, Bheem Singh

2018-06-01

In the present paper, the numerical simulation of Inertial Alfven wave (IAW) in low-β plasma applicable to the auroral region at 1700 km was studied. It leads to the formation of localized structures when the nonlinearity arises due to ponderomotive effect and Joule heating. The effect of perturbation and magnitude of pump IAW, formed the localized structures of magnetic field, has been studied. The formed localized structures at different times and average spectral index scaling of power spectrum have been observed. Results obtained from simulation reveal that spectrum steepens with power law index ˜ -3.5 for shorter wavelength. These localized structures could be a source of particle acceleration and heating by pump IAW in low- β plasma.

Determining localized garment insulation values from manikin studies: computational method and results.

PubMed

Nelson, D A; Curlee, J S; Curran, A R; Ziriax, J M; Mason, P A

2005-12-01

The localized thermal insulation value expresses a garment's thermal resistance over the region which is covered by the garment, rather than over the entire surface of a subject or manikin. The determination of localized garment insulation values is critical to the development of high-resolution models of sensible heat exchange. A method is presented for determining and validating localized garment insulation values, based on whole-body insulation values (clo units) and using computer-aided design and thermal analysis software. Localized insulation values are presented for a catalog consisting of 106 garments and verified using computer-generated models. The values presented are suitable for use on volume element-based or surface element-based models of heat transfer involving clothed subjects.

Low temperature heat capacities and thermodynamic functions described by Debye-Einstein integrals.

PubMed

Gamsjäger, Ernst; Wiessner, Manfred

2018-01-01

Thermodynamic data of various crystalline solids are assessed from low temperature heat capacity measurements, i.e., from almost absolute zero to 300 K by means of semi-empirical models. Previous studies frequently present fit functions with a large amount of coefficients resulting in almost perfect agreement with experimental data. It is, however, pointed out in this work that special care is required to avoid overfitting. Apart from anomalies like phase transformations, it is likely that data from calorimetric measurements can be fitted by a relatively simple Debye-Einstein integral with sufficient precision. Thereby, reliable values for the heat capacities, standard enthalpies, and standard entropies at T  = 298.15 K are obtained. Standard thermodynamic functions of various compounds strongly differing in the number of atoms in the formula unit can be derived from this fitting procedure and are compared to the results of previous fitting procedures. The residuals are of course larger when the Debye-Einstein integral is applied instead of using a high number of fit coefficients or connected splines, but the semi-empiric fit coefficients keep their meaning with respect to physics. It is suggested to use the Debye-Einstein integral fit as a standard method to describe heat capacities in the range between 0 and 300 K so that the derived thermodynamic functions are obtained on the same theory-related semi-empiric basis. Additional fitting is recommended when a precise description for data at ultra-low temperatures (0-20 K) is requested.

Study of the Productivity and Surface Quality of Hybrid EDM

NASA Astrophysics Data System (ADS)

Wankhade, Sandeepkumar Haribhau; Sharma, Sunil Bansilal

2016-01-01

The development of new, advanced engineering materials and the need for precise prototypes and low-volume production have made the electric discharge machining (EDM), an important manufacturing process to meet such demands. It is capable of machining geometrically complex and hard material components, that are precise and difficult-to-machine such as heat treated tool steels, composites, super alloys, ceramics, carbides etc. Conversely the low MRR limits its productivity. Abrasive water jet machine (AJM) tools are quick to setup and offer quick turn-around on the machine and could make parts out of virtually any material. They do not heat the material hence no heat affected zone and can make any intricate shape easily. The main advantages are flexibility, low heat production and ability to machine hard and brittle materials. Main disadvantages comprise the process produces a tapered cut and health hazards due to dry abrasives. To overcome the limitations and exploit the best of each of above processes; an attempt has been made to hybridize the processes of AJM and EDM. The appropriate abrasives routed with compressed air through the hollow electrode to construct the hybrid process i.e., abrasive jet electric discharge machining (AJEDM), the high speed abrasives could impinge on the machined surface to remove the recast layer caused by EDM process. The main process parameters were varied to explore their effects and experimental results show that AJEDM enhances the machining efficiency with better surface finish hence can fit the requirements of modern manufacturing applications.

Steady-state low thermal resistance characterization apparatus: The bulk thermal tester

DOE Office of Scientific and Technical Information (OSTI.GOV)

Burg, Brian R.; Kolly, Manuel; Blasakis, Nicolas

The reliability of microelectronic devices is largely dependent on electronic packaging, which includes heat removal. The appropriate packaging design therefore necessitates precise knowledge of the relevant material properties, including thermal resistance and thermal conductivity. Thin materials and high conductivity layers make their thermal characterization challenging. A steady state measurement technique is presented and evaluated with the purpose to characterize samples with a thermal resistance below 100 mm{sup 2} K/W. It is based on the heat flow meter bar approach made up by two copper blocks and relies exclusively on temperature measurements from thermocouples. The importance of thermocouple calibration is emphasizedmore » in order to obtain accurate temperature readings. An in depth error analysis, based on Gaussian error propagation, is carried out. An error sensitivity analysis highlights the importance of the precise knowledge of the thermal interface materials required for the measurements. Reference measurements on Mo samples reveal a measurement uncertainty in the range of 5% and most accurate measurements are obtained at high heat fluxes. Measurement techniques for homogeneous bulk samples, layered materials, and protruding cavity samples are discussed. Ultimately, a comprehensive overview of a steady state thermal characterization technique is provided, evaluating the accuracy of sample measurements with thermal resistances well below state of the art setups. Accurate characterization of materials used in heat removal applications, such as electronic packaging, will enable more efficient designs and ultimately contribute to energy savings.« less

Nanocalorimeter platform for in situ specific heat measurements and x-ray diffraction at low temperature

DOE Office of Scientific and Technical Information (OSTI.GOV)

Willa, K.; Diao, Z.; Campanini, D.

Recent advances in electronics and nanofabrication have enabled membrane-based nanocalorimetry for measurements of the specific heat of microgram-sized samples. We have integrated a nanocalorimeter platform into a 4.5 T split-pair vertical-field magnet to allow for the simultaneous measurement of the specific heat and x-ray scattering in magnetic fields and at temperatures as low as 4 K. This multi-modal approach empowers researchers to directly correlate scattering experiments with insights from thermodynamic properties including structural, electronic, orbital, and magnetic phase transitions. The use of a nanocalorimeter sample platform enables numerous technical advantages: precise measurement and control of the sample temperature, quantification ofmore » beam heating effects, fast and precise positioning of the sample in the x-ray beam, and fast acquisition of x-ray scans over a wide temperature range without the need for time-consuming re-centering and re-alignment. Furthermore, on an YBa2Cu3O7-delta crystal and a copper foil, we demonstrate a novel approach to x-ray absorption spectroscopy by monitoring the change in sample temperature as a function of incident photon energy. Finally, we illustrate the new insights that can be gained from in situ structural and thermodynamic measurements by investigating the superheated state occurring at the first-order magneto-elastic phase transition of Fe2P, a material that is of interest for magnetocaloric applications.« less

Adaptive heat pump and battery storage demand side energy management

NASA Astrophysics Data System (ADS)

Sobieczky, Florian; Lettner, Christian; Natschläger, Thomas; Traxler, Patrick

2017-11-01

An adaptive linear model predictive control strategy is introduced for the problem of demand side energy management, involving a photovoltaic device, a battery, and a heat pump. Moreover, the heating influence of solar radiation via the glass house effect is considered. Global sunlight radiation intensity and the outside temperature are updated by weather forecast data. The identification is carried out after adapting to a time frame witch sufficiently homogeneous weather. In this way, in spite of the linearity an increase in precision and cost reduction of up to 46% is achieved. It is validated for an open and closed loop version of the MPC problem using real data of the ambient temperature and the global radiation.

Precise Truss Assembly Using Commodity Parts and Low Precision Welding

NASA Technical Reports Server (NTRS)

Komendera, Erik; Reishus, Dustin; Dorsey, John T.; Doggett, W. R.; Correll, Nikolaus

2014-01-01

Hardware and software design and system integration for an intelligent precision jigging robot (IPJR), which allows high precision assembly using commodity parts and low-precision bonding, is described. Preliminary 2D experiments that are motivated by the problem of assembling space telescope optical benches and very large manipulators on orbit using inexpensive, stock hardware and low-precision welding are also described. An IPJR is a robot that acts as the precise "jigging", holding parts of a local structure assembly site in place, while an external low precision assembly agent cuts and welds members. The prototype presented in this paper allows an assembly agent (for this prototype, a human using only low precision tools), to assemble a 2D truss made of wooden dowels to a precision on the order of millimeters over a span on the order of meters. The analysis of the assembly error and the results of building a square structure and a ring structure are discussed. Options for future work, to extend the IPJR paradigm to building in 3D structures at micron precision are also summarized.

Thermal therapy techniques for skin and superficial tissue disease

NASA Astrophysics Data System (ADS)

Stauffer, Paul R.

2000-01-01

There are numerous diseases and abnormal growths and conditions that afflict the skin and underlying superficial tissues. In addition to cancers such as primary, recurrent, and metastatic melanomas and carcinomas, there are many non-malignant conditions such as psoriasis plaques, port wine stains, warts, and superficial cut and bum wounds. Many of these clinical conditions have been shown responsive to treatment with thermal therapy - either low temperature freezing (cryotherapy),. moderate temperature warming to about 41-45°C (hyperthermia), or high temperature (>50°C) ablation or coagulation necrosis therapy. Because both very low and very high temperature therapies are for the most part non-selectively destructive in nature, they normally are used for applications where therapy can be localized precisely in the desired target and some necrosis of adjacent normal tissues is acceptable. With the exception of precision controlled cryotherapy or laser surgery (e.g. wart, mole, tattoo and port wine stain removal) or focal thermal surgery of small deep-seated nodules, it is generally preferred to use moderate thermal therapy (hyperthermia) in the treatment of skin and subcutaneous tissue disease in order to preserve the protective barrier characteristic of intact skin within the target region while inducing more subtle long term therapeutic improvement in the disease condition. This type of subtle thermal therapy is usually administered in combination with one or more other therapies such as radiation or chemotherapy - something with a differential effect on the target and surrounding normal tissues that can be magnified by the adjuvant use of heat.

Engineering on-chip nanoporous gold material libraries via precision photothermal treatment [Precision Photothermal Annealing of Nanoporous Gold Thin Films for the Microfabrication of a Single-ship Material Libraries

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chapman, Christopher A. R.; Wang, Ling; Biener, Juergen

Single-chip material libraries of thin films of nanostructured materials are a promising approach for high throughput studies of structure-property relationship in the fields of physics and biology. Nanoporous gold (np-Au), produced by an alloy corrosion process, is a nanostructured material of specific interest in both these fields. One attractive property of np-Au is its self-similar coarsening behavior by thermally induced surface diffusion. However, traditional heat application techniques for the modification of np-Au are bulk processes that cannot be used to generate a library of different pore sizes on a single chip. Laser micromachining offers an attractive solution to this problemmore » by providing a means to apply energy with high spatial and temporal resolution. In our present study we use finite element multiphysics simulations to predict the effects of laser mode (continuous-wave vs. pulsed) and supporting substrate thermal conductivity on the local np-Au film temperatures during photothermal annealing and subsequently investigate the mechanisms by which the np-Au network is coarsening. Our simulations predict that continuous-wave mode laser irradiation on a silicon supporting substrate supports the widest range of morphologies that can be created through the photothermal annealing of thin film np-Au. Using this result we successfully fabricate a single-chip material library consisting of 81 np-Au samples of 9 different morphologies for use in increased throughput material interaction studies.« less

Engineering on-chip nanoporous gold material libraries via precision photothermal treatment [Precision Photothermal Annealing of Nanoporous Gold Thin Films for the Microfabrication of a Single-ship Material Libraries

DOE PAGES

Chapman, Christopher A. R.; Wang, Ling; Biener, Juergen; ...

2016-01-01

Single-chip material libraries of thin films of nanostructured materials are a promising approach for high throughput studies of structure-property relationship in the fields of physics and biology. Nanoporous gold (np-Au), produced by an alloy corrosion process, is a nanostructured material of specific interest in both these fields. One attractive property of np-Au is its self-similar coarsening behavior by thermally induced surface diffusion. However, traditional heat application techniques for the modification of np-Au are bulk processes that cannot be used to generate a library of different pore sizes on a single chip. Laser micromachining offers an attractive solution to this problemmore » by providing a means to apply energy with high spatial and temporal resolution. In our present study we use finite element multiphysics simulations to predict the effects of laser mode (continuous-wave vs. pulsed) and supporting substrate thermal conductivity on the local np-Au film temperatures during photothermal annealing and subsequently investigate the mechanisms by which the np-Au network is coarsening. Our simulations predict that continuous-wave mode laser irradiation on a silicon supporting substrate supports the widest range of morphologies that can be created through the photothermal annealing of thin film np-Au. Using this result we successfully fabricate a single-chip material library consisting of 81 np-Au samples of 9 different morphologies for use in increased throughput material interaction studies.« less

Determination of the boiling-point distribution by simulated distillation from n-pentane through n-tetratetracontane in 70 to 80 seconds.

PubMed

Lubkowitz, Joaquin A; Meneghini, Roberto I

2002-01-01

This work presents the carrying out of boiling-point distributions by simulated distillation with direct-column heating rather than oven-column heating. Column-heating rates of 300 degrees C/min are obtained yielding retention times of 73 s for n-tetratetracontane. The calibration curves of the retention time versus the boiling point, in the range of n-pentane to n-tetratetracontane, are identical to those obtained by slower oven-heating rates. The boiling-point distribution of the reference gas oil is compared with that obtained with column oven heating at rates of 15 to 40 degrees C/min. The results show boiling-point distribution values nearly the same (1-2 degrees F) as those obtained with oven column heating from the initial boiling point to 80% distilled off. Slightly higher differences are obtained (3-4 degrees F) for the 80% distillation to final boiling-point interval. Nonetheless, allowed consensus differences are never exceeded. Precision of the boiling-point distributions (expressed as standard deviations) are 0.1-0.3% for the data obtained in the direct column-heating mode.

Finger heat flux/temperature as an indicator of thermal imbalance with application for extravehicular activity.

PubMed

Koscheyev, Victor S; Leon, Gloria R; Coca, Aitor

2005-11-01

The designation of a simple, non-invasive, and highly precise method to monitor the thermal status of astronauts is important to enhance safety during extravehicular activities (EVA) and onboard emergencies. Finger temperature (Tfing), finger heat flux, and indices of core temperature (Tc) [rectal (Tre), ear canal (Tec)] were assessed in 3 studies involving different patterns of heat removal/insertion from/to the body by a multi-compartment liquid cooling/warming garment (LCWG). Under both uniform and nonuniform temperature conditions on the body surface, Tfing and finger heat flux were highly correlated with garment heat flux, and also highly correlated with each other. Tc responses did not adequately reflect changes in thermal balance during the ongoing process of heat insertion/removal from the body. Overall, Tfing/finger heat flux adequately reflected the initial destabilization of thermal balance, and therefore appears to have significant potential as a useful index for monitoring and maintaining thermal balance and comfort in extreme conditions in space as well as on Earth. c2005 Elsevier Ltd. All rights reserved.

Towards real-time thermometry using simultaneous multislice MRI

NASA Astrophysics Data System (ADS)

Borman, P. T. S.; Bos, C.; de Boorder, T.; Raaymakers, B. W.; Moonen, C. T. W.; Crijns, S. P. M.

2016-09-01

MR-guided thermal therapies, such as high-intensity focused ultrasound (MRgHIFU) and laser-induced thermal therapy (MRgLITT) are increasingly being applied in oncology and neurology. MRI is used for guidance since it can measure temperature noninvasively based on the proton resonance frequency shift (PRFS). For therapy guidance using PRFS thermometry, high temporal resolution and large spatial coverage are desirable. We propose to use the parallel imaging technique simultaneous multislice (SMS) in combination with controlled aliasing (CAIPIRINHA) to accelerate the acquisition. We compare this with the sensitivity encoding (SENSE) acceleration technique. Two experiments were performed to validate that SMS can be used to increase the spatial coverage or the temporal resolution. The first was performed in agar gel using LITT heating and a gradient-echo sequence with echo-planar imaging (EPI), and the second was performed in bovine muscle using HIFU heating and a gradient-echo sequence without EPI. In both experiments temperature curves from an unaccelerated scan and from SMS, SENSE, and SENSE/SMS accelerated scans were compared. The precision was quantified by a standard deviation analysis of scans without heating. Both experiments showed a good agreement between the temperature curves obtained from the unaccelerated, and SMS accelerated scans, confirming that accuracy was maintained during SMS acceleration. The standard deviations of the temperature measurements obtained with SMS were significantly smaller than when SENSE was used, implying that SMS allows for higher acceleration. In the LITT and HIFU experiments SMS factors up to 4 and 3 were reached, respectively, with a loss of precision of less than a factor of 3. Based on these results we conclude that SMS acceleration of PRFS thermometry is a valuable addition to SENSE, because it allows for a higher temporal resolution or bigger spatial coverage, with a higher precision.

Boron-doped nanodiamonds as possible agents for local hyperthermia

NASA Astrophysics Data System (ADS)

Vervald, A. M.; Burikov, S. A.; Vlasov, I. I.; Ekimov, E. A.; Shenderova, O. A.; Dolenko, T. A.

2017-04-01

In this work, the effective heating of surrounding water by heavily-boron-doped nanodiamonds (NDs) under laser irradiation of visible wavelength was found. Using Raman scattering spectroscopy of aqueous suspensions of boron-doped NDs, it was found that this abnormally high heating results in the weakening of hydrogen bonds much more so (2-5 times stronger) than for undoped NDs. The property of boron-doped NDs to heat a solvent under the influence of laser radiation (1-5 W cm-2) opens broad prospects for their use to create nanoagents for medical oncology and local hyperthermia.

Investigation of Temperature Change under Influence of Ultrashort Laser Pulses Taking into Account Relaxation Properties of Materials

NASA Astrophysics Data System (ADS)

Eremin, A. V.; Kudinov, V. A.; Stefanyuk, E. V.; Kudinov, I. V.

2018-03-01

By using the modified Fourier law’s formula considering the relaxation of heat flow and temperature gradient, a mathematical model of the local non-equilibrium process of plate heating with ultrashort laser pulses was developed. The research showed that consideration of non-locality results in the delayed plate heat up irrespective of the laser radiation flow intensity. It was also shown that in consideration of the relaxation phenomena, the boundary conditions may not be fulfilled immediately – they may be set only within a definite range of the initial time.

Standard B-Mode Ultrasound Measures Local Carotid Artery Characteristics as Reliably as Radiofrequency Phase Tracking in Symptomatic Carotid Artery Patients.

PubMed

Steinbuch, Jeire; Hoeks, Arnold P G; Hermeling, Evelien; Truijman, Martine T B; Schreuder, Floris H B M; Mess, Werner H

2016-02-01

Local arterial stiffness can be assessed with high accuracy and precision by measuring arterial distension on the basis of phase tracking of radiofrequency ultrasound signals acquired at a high frame rate. However, in clinical practice, B-mode ultrasound registrations are made at a low frame rate (20-50 Hz). We compared the accuracy and intra-subject precision of edge tracking and phase tracking distension in symptomatic carotid artery patients. B-mode ultrasound recordings (40 mm, 37 fps) and radiofrequency recordings (31 lines covering 29 mm, 300 fps) were acquired from the left common carotid artery of 30 patients (aged 45-88 y) with recent cerebrovascular events. To extract the distension, semi-automatic echo edge and phase tracking algorithms were applied to B-mode and radiofrequency recordings, respectively. Both methods exhibited a similar intra-subject precision for distension (standard deviation = 44 μm and 47 μm, p = 0.66) and mean distension (difference: -6 ± 69 μm, p = 0.67). Intra-subject distension inhomogeneity tends to be larger for edge tracking (difference: 15 ± 35 μm, p = 0.04). Standard B-mode scanners are suitable for measuring local artery characteristics in symptomatic carotid artery patients with good precision and accuracy. Copyright © 2016 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.

Whole-body heat loss during exercise in the heat is not impaired in type 1 diabetes.

PubMed

Stapleton, Jill M; Yardley, Jane E; Boulay, Pierre; Sigal, Ronald J; Kenny, Glen P

2013-09-01

The objective of this study is to determine whether individuals with type 1 diabetes exhibit impairments in local and whole-body heat loss responses that could affect core temperature regulation during exercise in the heat compared with matched, nondiabetic individuals. Twelve otherwise healthy individuals with type 1 diabetes (HbA1c = 7.7% ± 0.3%) and 12 controls matched for age, sex, body surface area, and physical fitness cycled continuously for 60 min at a set rate of metabolic heat production (approximately 400 W) in a whole-body direct calorimeter (35°C and 20% relative humidity). Local sweat rate (ventilated capsule) was measured on the back and skin blood flow (laser Doppler velocimetry) on the forearm. Core (rectal and esophageal) and mean skin temperatures and heart rate were measured continuously. Whole-body heat exchange and change in body heat content were measured using simultaneous direct whole-body and indirect calorimetry. The change (mean ± SE) in body heat content was similar between groups during exercise (diabetes, 409 ± 27 kJ; control, 386 ± 33 kJ; P = 0.584) and recovery (diabetes, -115 ± 16 kJ; control, -93 ± 24 kJ; P = 0.457). Local heat loss responses of sweating (P = 0.783) and skin blood flow (P = 0.078) as well as rectal temperature (diabetes, 37.87°C ± 0.10°C; control, 37.85°C; ± 0.13°C; P = 0.977) and heart rate (diabetes, 130 ± 9 beats·min, vs control, 126 ± 8 beats·min, P = 0.326) were comparable at the end of the exercise period. During light-to-moderate-intensity exercise performed under conditions permitting full sweat evaporation, otherwise healthy type 1 diabetic individuals did not show impaired heat loss responses during heat exposure when compared with matched individuals without diabetes.

Response of melanoma to heat and radiation therapy--a review of the literature and experience from The Prince of Wales Hospital, Sydney.

PubMed

Mameghan, H; Knittel, T

1988-11-07

Our review of the literature indicates that radiotherapy and/or heat therapy can provide local control of recurrent or metastatic melanoma in a large proportion of patients. This has undoubted value in the local palliation of symptoms and, in the absence of disseminated disease, can be curative. At The Prince of Wales Hospital, Sydney, we have studied the response of melanoma lesions to heat and radiation therapy and have assessed the reaction in the adjacent normal skin. Thirty-two melanoma lesions that were measurable in 12 patients received radiotherapy and heat therapy in different combinations and dose schedules (15 lesions received radiotherapy alone, six lesions received heat therapy alone, and 11 lesions received combined radiation and heat therapy). The acute normal skin reaction was compared between lesions that received single modality radiation or heat therapy and those that received the combination of heat and radiation therapy. A moderate or severe reaction developed at six of the 21 sites that were treated by a single modality, and at four of the 11 sites that received combined heat and radiation therapy (P = 0.7), and all healed within a few days. Evaluation of the melanoma response to therapy was possible only in 26 of the 32 lesions that were treated because two patients died soon after therapy and the response of their six lesions was not evaluable. A complete response occurred in 14 (54%) of 26 lesions and a partial response occurred in 10 (38%) of 26 lesions. The objective response by treatment modality was 10 of 15 lesions for radiotherapy, six of six lesions for heat therapy and eight of 11 lesions for both therapies combined. We conclude that radiotherapy and heat therapy, separately or combined, produce acceptably-low damage to normal tissue and highly-satisfactory local control of melanoma.

When do Indians feel hot? Internet searches indicate seasonality suppresses adaptation to heat

NASA Astrophysics Data System (ADS)

Singh, Tanya; Siderius, Christian; Van der Velde, Ype

2018-05-01

In a warming world an increasing number of people are being exposed to heat, making a comfortable thermal environment an important need. This study explores the potential of using Regional Internet Search Frequencies (RISF) for air conditioning devices as an indicator for thermal discomfort (i.e. dissatisfaction with the thermal environment) with the aim to quantify the adaptation potential of individuals living across different climate zones and at the high end of the temperature range, in India, where access to health data is limited. We related RISF for the years 2011–2015 to daily daytime outdoor temperature in 17 states and determined at which temperature RISF for air conditioning starts to peak, i.e. crosses a ‘heat threshold’, in each state. Using the spatial variation in heat thresholds, we explored whether people continuously exposed to higher temperatures show a lower response to heat extremes through adaptation (e.g. physiological, behavioural or psychological). State-level heat thresholds ranged from 25.9 °C in Madhya Pradesh to 31.0 °C in Orissa. Local adaptation was found to occur at state level: the higher the average temperature in a state, the higher the heat threshold; and the higher the intra-annual temperature range (warmest minus coldest month) the lower the heat threshold. These results indicate there is potential within India to adapt to warmer temperatures, but that a large intra-annual temperature variability attenuates this potential to adapt to extreme heat. This winter ‘reset’ mechanism should be taken into account when assessing the impact of global warming, with changes in minimum temperatures being an important factor in addition to the change in maximum temperatures itself. Our findings contribute to a better understanding of local heat thresholds and people’s adaptive capacity, which can support the design of local thermal comfort standards and early heat warning systems.

Thermal footprints in groundwater of central European cities

NASA Astrophysics Data System (ADS)

Bayer, P.; Menberg, K.; Blum, P.

2014-12-01

Atmospheric thermal pollution in densely populated areas is recognized as a severe problem with consequences for human health, and considerable efforts are being taken to mitigate heat stress in cities. However, anthropogenic activities also influence the thermal environment beneath the ground level, with commonly growing temperatures that affect groundwater ecology and geothermal use efficiency. In our work, we identify the controlling mechanisms for the long-term evolution of such urban heat islands. The shallow groundwater temperatures in several central European cities such as Cologne, Karlsruhe, Munich, Berlin and Zurich were mapped at high spatial and temporal resolution. Thermal anomalies were found to be highly heterogeneous with local hot spots showing temperatures of more than 20°C. Accordingly, these urban regions show a considerable groundwater warming in comparison to undisturbed temperatures of 8-11°C. Examination of potential heat sources by analytical modelling reveals that increased ground surface temperatures and basements of buildings act as dominant drivers for the anthropogenic heat input into the groundwater. The factors are revealed to be case-specific and they may have pronounced local or regional effects. Typical local factors are for example buried district heating networks. In selected cities we find that the average urban heat flux is around one order of magnitude higher than the elevated ground heat flux due to recent climate change. Additionally, such as observed in Zurich, naturally controlled temperature variations can be substantial and they are shown to wash out anthropogenic thermal footprints.

Critical heat flux (CHF) phenomenon on a downward facing curved surface

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cheung, F.B.; Haddad, K.H.; Liu, Y.C.

1997-06-01

This report describes a theoretical and experimental study of the boundary layer boiling and critical heat flux phenomena on a downward facing curved heating surface, including both hemispherical and toroidal surfaces. A subscale boundary layer boiling (SBLB) test facility was developed to measure the spatial variation of the critical heat flux and observe the underlying mechanisms. Transient quenching and steady-state boiling experiments were performed in the SBLB facility under both saturated and subcooled conditions to obtain a complete database on the critical heat flux. To complement the experimental effort, an advanced hydrodynamic CHF model was developed from the conservation lawsmore » along with sound physical arguments. The model provides a clear physical explanation for the spatial variation of the CHF observed in the SBLB experiments and for the weak dependence of the CHF data on the physical size of the vessel. Based upon the CHF model, a scaling law was established for estimating the local critical heat flux on the outer surface of a heated hemispherical vessel that is fully submerged in water. The scaling law, which compares favorably with all the available local CHF data obtained for various vessel sizes, can be used to predict the local CHF limits on large commercial-size vessels. This technical information represents one of the essential elements that is needed in assessing the efficacy of external cooling of core melt by cavity flooding as a severe accident management strategy. 83 figs., 3 tabs.« less

Utilization of Plasmonic and Photonic Crystal Nanostructures for Enhanced Micro- and Nanoparticle Manipulation

PubMed Central

Simmons, Cameron S.; Knouf, Emily Christine; Tewari, Muneesh; Lin, Lih Y.

2011-01-01

A method to manipulate the position and orientation of submicron particles nondestructively would be an incredibly useful tool for basic biological research. Perhaps the most widely used physical force to achieve noninvasive manipulation of small particles has been dielectrophoresis(DEP).1 However, DEP on its own lacks the versatility and precision that are desired when manipulating cells since it is traditionally done with stationary electrodes. Optical tweezers, which utilize a three dimensional electromagnetic field gradient to exert forces on small particles, achieve this desired versatility and precision.2 However, a major drawback of this approach is the high radiation intensity required to achieve the necessary force to trap a particle which can damage biological samples.3 A solution that allows trapping and sorting with lower optical intensities are optoelectronic tweezers (OET) but OET's have limitations with fine manipulation of small particles; being DEP-based technology also puts constraint on the property of the solution.4,5 This video article will describe two methods that decrease the intensity of the radiation needed for optical manipulation of living cells and also describe a method for orientation control. The first method is plasmonic tweezers which use a random gold nanoparticle (AuNP) array as a substrate for the sample as shown in Figure 1. The AuNP array converts the incident photons into localized surface plasmons (LSP) which consist of resonant dipole moments that radiate and generate a patterned radiation field with a large gradient in the cell solution. Initial work on surface plasmon enhanced trapping by Righini et al and our own modeling have shown the fields generated by the plasmonic substrate reduce the initial intensity required by enhancing the gradient field that traps the particle.6,7,8 The plasmonic approach allows for fine orientation control of ellipsoidal particles and cells with low optical intensities because of more efficient optical energy conversion into mechanical energy and a dipole-dependent radiation field. These fields are shown in figure 2 and the low trapping intensities are detailed in figures 4 and 5. The main problems with plasmonic tweezers are that the LSP's generate a considerable amount of heat and the trapping is only two dimensional. This heat generates convective flows and thermophoresis which can be powerful enough to expel submicron particles from the trap.9,10 The second approach that we will describe is utilizing periodic dielectric nanostructures to scatter incident light very efficiently into diffraction modes, as shown in figure 6.11 Ideally, one would make this structure out of a dielectric material to avoid the same heating problems experienced with the plasmonic tweezers but in our approach an aluminum-coated diffraction grating is used as a one-dimensional periodic dielectric nanostructure. Although it is not a semiconductor, it did not experience significant heating and effectively trapped small particles with low trapping intensities, as shown in figure 7. Alignment of particles with the grating substrate conceptually validates the proposition that a 2-D photonic crystal could allow precise rotation of non-spherical micron sized particles.10 The efficiencies of these optical traps are increased due to the enhanced fields produced by the nanostructures described in this paper. PMID:21988841

An improved algorithm for the modeling of vapor flow in heat pipes

NASA Technical Reports Server (NTRS)

Tower, Leonard K.; Hainley, Donald C.

1989-01-01

A heat pipe vapor flow algorithm suitable for use in codes on microcomputers is presented. The incompressible heat pipe vapor flow studies of Busse are extended to incorporate compressibility effects. The Busse velocity profile factor is treated as a function of temperature and pressure. The assumption of a uniform saturated vapor temperature determined by the local pressure at each cross section of the pipe is not made. Instead, a mean vapor temperature, defined by an energy integral, is determined in the course of the solution in addition to the pressure, saturation temperature at the wall, and the Busse velocity profile factor. For alkali metal working fluids, local species equilibrium is assumed. Temperature and pressure profiles are presented for several cases involving sodium heat pipes. An example for a heat pipe with an adiabatic section and two evaporators in sequence illustrates the ability to handle axially varying heat input. A sonic limit plot for a short evaporator falls between curves for the Busse and Levy inviscid sonic limits.

An improved algorithm for the modeling of vapor flow in heat pipes

NASA Astrophysics Data System (ADS)

Tower, Leonard K.; Hainley, Donald C.

1989-12-01

A heat pipe vapor flow algorithm suitable for use in codes on microcomputers is presented. The incompressible heat pipe vapor flow studies of Busse are extended to incorporate compressibility effects. The Busse velocity profile factor is treated as a function of temperature and pressure. The assumption of a uniform saturated vapor temperature determined by the local pressure at each cross section of the pipe is not made. Instead, a mean vapor temperature, defined by an energy integral, is determined in the course of the solution in addition to the pressure, saturation temperature at the wall, and the Busse velocity profile factor. For alkali metal working fluids, local species equilibrium is assumed. Temperature and pressure profiles are presented for several cases involving sodium heat pipes. An example for a heat pipe with an adiabatic section and two evaporators in sequence illustrates the ability to handle axially varying heat input. A sonic limit plot for a short evaporator falls between curves for the Busse and Levy inviscid sonic limits.

Smart grid integration of small-scale trigeneration systems

NASA Astrophysics Data System (ADS)

Vacheva, Gergana; Kanchev, Hristiyan; Hinov, Nikolay

2017-12-01

This paper presents a study on the possibilities for implementation of local heating, air-conditioning and electricity generation (trigeneration) as distributed energy resource in the Smart Grid. By the means of microturbine-based generators and absorption chillers buildings are able to meet partially or entirely their electrical load curve or even supply power to the grid by following their heating and air-conditioning daily schedule. The principles of small-scale cooling, heating and power generation systems are presented at first, then the thermal calculations of an example building are performed: the heat losses due to thermal conductivity and the estimated daily heating and air-conditioning load curves. By considering daily power consumption curves and weather data for several winter and summer days, the heating/air-conditioning schedule is estimated and the available electrical energy from a microturbine-based cogeneration system is estimated. Simulation results confirm the potential of using cogeneration and trigeneration systems for local distributed electricity generation and grid support in the daily peaks of power consumption.

The influence of PM2.5 coal power plant emissions on environment PM2.5 in Jilin Province, China

NASA Astrophysics Data System (ADS)

Sun, Ye; Li, Zhi; Zhang, Dan; Zhang, He; Zhang, Huafei

2018-02-01

In recent years, in the Northeast of China, the heating period comes with large range of haze weather. All the units of coal power plants in Jilin Province have completed the cogeneration reformation; they provide local city heat energy. Many people believe that coal power plants heating caused the heavy haze. In is paper, by compared concentration of PM2.5 in environment in heating period and non heating period, meanwhile the capacity of local coal power plants, conclude that the PM2.5 emission of coal power plants not directly cause the heavy haze in Changchun and Jilin in the end of October and early November. In addition, the water-soluble iron composition of PM2.5 coal power plant emissions is compared with environment, which further proves that the heating supply in coal power plants is not the cause of high concentration of PM2.5 in Jilin province.

Mathematical modeling of the process of determining the standards for process losses in the transfer of thermal energy of the coolant

NASA Astrophysics Data System (ADS)

Akhmetova, I. G.; Chichirova, N. D.

2017-11-01

Currently the actual problem is a precise definition of the normative and actual heat loss. Existing methods - experimental, on metering devices, on the basis of mathematical modeling methods are not without drawbacks. Heat losses establishing during the heat carrier transport has an impact on the tariff structure of heat supply organizations. This quantity determination also promotes proper choice of main and auxiliary equipment power, temperature chart of heat supply networks, as well as the heating system structure choice with the decentralization. Calculation of actual heat loss and their comparison with standard values justifies the performance of works on improvement of the heat networks with the replacement of piping or its insulation. To determine the cause of discrepancies between normative and actual heat losses thermal tests on the magnitude of the actual heat losses in the 124 sections of heat networks in Kazan. As were carried out the result mathematical model of the regulatory definition of heat losses is developed and tested. This model differ from differs the existing according the piping insulation type. The application of this factor will bring the value of calculative normative losses heat energy to their actual value. It is of great importance for enterprises operating distribution networks and because of the conditions of their configuration and extensions do not have the technical ability to produce thermal testing.

Heat and mass transfer are in the interaction of multi-pulsed spray with vertical surfaces in the regime of evaporative cooling

NASA Astrophysics Data System (ADS)

Karpov, P. N.; Nazarov, A. D.; Serov, A. F.; Terekhov, V. I.

2017-10-01

Sprays with a periodic supply drop phase have great opportunities to control the processes of heat transfer. We can achieve optimal evaporative modes of cooling by changing the pulse duration and the repetition frequency while minimizing flow of the liquid phase. Experimental data of investigation of local heat transfer for poorly heated large surface obtained on the original stand with multi nozzle managed the irrigation system impact of the gas-droplet flow present in this work. Researches on the contribution to the intensification of spray options were conducted. Also the growth rate was integral and local heat. Information instantaneous distribution of the heat flux in the description of the processes have helped us. Managed to describe two basic modes of heat transfer: Mode “insular” foil cooling and thick foil with forming of streams. Capacitive sensors allow to monitor the dynamics of the foil thickness, the birth-belt flow, forming and the evolution of waves generated by “bombing” the surface with the droplets.

Extreme Heat and Health: Perspectives from Health Service Providers in Rural and Remote Communities in South Australia

PubMed Central

Williams, Susan; Bi, Peng; Newbury, Jonathan; Robinson, Guy; Pisaniello, Dino; Saniotis, Arthur; Hansen, Alana

2013-01-01

Among the challenges for rural communities and health services in Australia, climate change and increasing extreme heat are emerging as additional stressors. Effective public health responses to extreme heat require an understanding of the impact on health and well-being, and the risk or protective factors within communities. This study draws on lived experiences to explore these issues in eleven rural and remote communities across South Australia, framing these within a socio-ecological model. Semi-structured interviews with health service providers (n = 13), and a thematic analysis of these data, has identified particular challenges for rural communities and their health services during extreme heat. The findings draw attention to the social impacts of extreme heat in rural communities, the protective factors (independence, social support, education, community safety), and challenges for adaptation (vulnerabilities, infrastructure, community demographics, housing and local industries). With temperatures increasing across South Australia, there is a need for local planning and low-cost strategies to address heat-exacerbating factors in rural communities, to minimise the impact of extreme heat in the future. PMID:24173140

Enhancing Localized Evaporation through Separated Light Absorbing Centers and Scattering Centers

PubMed Central

Zhao, Dengwu; Duan, Haoze; Yu, Shengtao; Zhang, Yao; He, Jiaqing; Quan, Xiaojun; Tao, Peng; Shang, Wen; Wu, Jianbo; Song, Chengyi; Deng, Tao

2015-01-01

This report investigates the enhancement of localized evaporation via separated light absorbing particles (plasmonic absorbers) and scattering particles (polystyrene nanoparticles). Evaporation has been considered as one of the most important phase-change processes in modern industries. To improve the efficiency of evaporation, one of the most feasible methods is to localize heat at the top water layer rather than heating the bulk water. In this work, the mixture of purely light absorptive plasmonic nanostructures such as gold nanoparticles and purely scattering particles (polystyrene nanoparticles) are employed to confine the incident light at the top of the solution and convert light to heat. Different concentrations of both the light absorbing centers and the light scattering centers were evaluated and the evaporation performance can be largely enhanced with the balance between absorbing centers and scattering centers. The findings in this study not only provide a new way to improve evaporation efficiency in plasmonic particle-based solution, but also shed lights on the design of new solar-driven localized evaporation systems. PMID:26606898

A transport model for non-local heating of electrons in ICP reactors

NASA Astrophysics Data System (ADS)

Chang, C. H.; Bose, Deepak

1998-10-01

A new model has been developed for non-local heating of electrons in ICP reactors, based on a hydrodynamic approach. The model has been derived using the electron momentum conservation in azimuthal direction with electromagnetic and frictional forces respectively as driving force and damper of harmonic oscillatory motion of electrons. The resulting transport equations include the convection of azimuthal electron momentum in radial and axial directions, thereby accounting for the non-local effects. The azimuthal velocity of electrons and the resulting electrical current are coupled to the Maxwell's relations, thus forming a self-consistent model for non-local heating. This model is being implemented along with a set of Navier-Stokes equations for plasma dynamics and gas flow to simulate low-pressure (few mTorr's) ICP discharges. Characteristics of nitrogen plasma in a TCP 300mm etch reactor is being studied. The results will be compared against the available Langmuir probe measurements [Collison et al. JVST-A 16(1),1998].

SU-E-J-03: Characterization of the Precision and Accuracy of a New, Preclinical, MRI-Guided Focused Ultrasound System for Image-Guided Interventions in Small-Bore, High-Field Magnets

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ellens, N; Farahani, K

2015-06-15

Purpose: MRI-guided focused ultrasound (MRgFUS) has many potential and realized applications including controlled heating and localized drug delivery. The development of many of these applications requires extensive preclinical work, much of it in small animal models. The goal of this study is to characterize the spatial targeting accuracy and reproducibility of a preclinical high field MRgFUS system for thermal ablation and drug delivery applications. Methods: The RK300 (FUS Instruments, Toronto, Canada) is a motorized, 2-axis FUS positioning system suitable for small bore (72 mm), high-field MRI systems. The accuracy of the system was assessed in three ways. First, the precisionmore » of the system was assessed by sonicating regular grids of 5 mm squares on polystyrene plates and comparing the resulting focal dimples to the intended pattern, thereby assessing the reproducibility and precision of the motion control alone. Second, the targeting accuracy was assessed by imaging a polystyrene plate with randomly drilled holes and replicating the hole pattern by sonicating the observed hole locations on intact polystyrene plates and comparing the results. Third, the practicallyrealizable accuracy and precision were assessed by comparing the locations of transcranial, FUS-induced blood-brain-barrier disruption (BBBD) (observed through Gadolinium enhancement) to the intended targets in a retrospective analysis of animals sonicated for other experiments. Results: The evenly-spaced grids indicated that the precision was 0.11 +/− 0.05 mm. When image-guidance was included by targeting random locations, the accuracy was 0.5 +/− 0.2 mm. The effective accuracy in the four rodent brains assessed was 0.8 +/− 0.6 mm. In all cases, the error appeared normally distributed (p<0.05) in both orthogonal axes, though the left/right error was systematically greater than the superior/inferior error. Conclusions: The targeting accuracy of this device is sub-millimeter, suitable for many preclinical applications including focused drug delivery and thermal therapy. Funding support provided by Philips Healthcare.« less

Regimes of heating and dynamical response in driven many-body localized systems

NASA Astrophysics Data System (ADS)

Gopalakrishnan, Sarang; Knap, Michael; Demler, Eugene

2016-09-01

We explore the response of many-body localized (MBL) systems to periodic driving of arbitrary amplitude, focusing on the rate at which they exchange energy with the drive. To this end, we introduce an infinite-temperature generalization of the effective "heating rate" in terms of the spread of a random walk in energy space. We compute this heating rate numerically and estimate it analytically in various regimes. When the drive amplitude is much smaller than the frequency, this effective heating rate is given by linear response theory with a coefficient that is proportional to the optical conductivity; in the opposite limit, the response is nonlinear and the heating rate is a nontrivial power law of time. We discuss the mechanisms underlying this crossover in the MBL phase. We comment on implications for the subdiffusive thermal phase near the MBL transition, and for response in imperfectly isolated MBL systems.

Transport lattice models of heat transport in skin with spatially heterogeneous, temperature-dependent perfusion

PubMed Central

Gowrishankar, TR; Stewart, Donald A; Martin, Gregory T; Weaver, James C

2004-01-01

Background Investigation of bioheat transfer problems requires the evaluation of temporal and spatial distributions of temperature. This class of problems has been traditionally addressed using the Pennes bioheat equation. Transport of heat by conduction, and by temperature-dependent, spatially heterogeneous blood perfusion is modeled here using a transport lattice approach. Methods We represent heat transport processes by using a lattice that represents the Pennes bioheat equation in perfused tissues, and diffusion in nonperfused regions. The three layer skin model has a nonperfused viable epidermis, and deeper regions of dermis and subcutaneous tissue with perfusion that is constant or temperature-dependent. Two cases are considered: (1) surface contact heating and (2) spatially distributed heating. The model is relevant to the prediction of the transient and steady state temperature rise for different methods of power deposition within the skin. Accumulated thermal damage is estimated by using an Arrhenius type rate equation at locations where viable tissue temperature exceeds 42°C. Prediction of spatial temperature distributions is also illustrated with a two-dimensional model of skin created from a histological image. Results The transport lattice approach was validated by comparison with an analytical solution for a slab with homogeneous thermal properties and spatially distributed uniform sink held at constant temperatures at the ends. For typical transcutaneous blood gas sensing conditions the estimated damage is small, even with prolonged skin contact to a 45°C surface. Spatial heterogeneity in skin thermal properties leads to a non-uniform temperature distribution during a 10 GHz electromagnetic field exposure. A realistic two-dimensional model of the skin shows that tissue heterogeneity does not lead to a significant local temperature increase when heated by a hot wire tip. Conclusions The heat transport system model of the skin was solved by exploiting the mathematical analogy between local thermal models and local electrical (charge transport) models, thereby allowing robust, circuit simulation software to obtain solutions to Kirchhoff's laws for the system model. Transport lattices allow systematic introduction of realistic geometry and spatially heterogeneous heat transport mechanisms. Local representations for both simple, passive functions and more complex local models can be easily and intuitively included into the system model of a tissue. PMID:15548324

In vivo determination of a modified heat capacity of small hepatocellular carcinomas prior to radiofrequency ablation: correlation with adjacent vasculature and tumour recurrence.

PubMed

Sheiman, Robert G; Mullan, Charles; Ahmed, Muneeb

2012-01-01

To calculate a modified heat capacity (mHC) of small hepatocellular carcinomas (HCCs) in vivo during radio frequency ablation (RFA) and to determine if mHC correlates with tumour vascularity, adjacent vessels or local recurrence. This study was IRB approved and informed consent was obtained from all patients. Before formal RFA, ambient HCC temperature and temperature 1 min after heating at constant wattage were measured in 29 patients. From temperature change and wattage, individual mHCs (joules required to increase tumour temperature by 1° Celsius) were calculated. Pre-RFA, three-phase computerised tomography (CT) scans were reviewed blindly for hepatic arteries, hepatic veins and portal veins abutting or within 3 mm of tumour edge from which twelve vascular parameters were quantified. Tumour enhancement (homogeneous or heterogeneous on arterial phase) was also assessed. Multiple regression was used to correlate mHC with vascular parameters and tumour enhancement. Cox proportional hazard model was used to examine the relationship of mHC to local recurrence. There was significant correlation of mHC with lesion enhancement (P = 0.0018), length of hepatic arteries (P < 0.0001) and total hepatic vein volume in contact with tumour (P = 0.016). No correlation was found with any non-abutting vessel or portal vein parameter. The chance of local recurrence increased with increasing mHC. Because the modified heat capacity of small HCCs in our study population correlated with HCC enhancement, abutting hepatic arteries, the volume of abutting hepatic veins and local recurrence, it may be an indicator of the heat sink effect (HSE) and supports the HSE as a risk factor for local recurrence.

A Spatial Framework to Map Heat Health Risks at Multiple Scales.

PubMed

Ho, Hung Chak; Knudby, Anders; Huang, Wei

2015-12-18

In the last few decades extreme heat events have led to substantial excess mortality, most dramatically in Central Europe in 2003, in Russia in 2010, and even in typically cool locations such as Vancouver, Canada, in 2009. Heat-related morbidity and mortality is expected to increase over the coming centuries as the result of climate-driven global increases in the severity and frequency of extreme heat events. Spatial information on heat exposure and population vulnerability may be combined to map the areas of highest risk and focus mitigation efforts there. However, a mismatch in spatial resolution between heat exposure and vulnerability data can cause spatial scale issues such as the Modifiable Areal Unit Problem (MAUP). We used a raster-based model to integrate heat exposure and vulnerability data in a multi-criteria decision analysis, and compared it to the traditional vector-based model. We then used the Getis-Ord G(i) index to generate spatially smoothed heat risk hotspot maps from fine to coarse spatial scales. The raster-based model allowed production of maps at spatial resolution, more description of local-scale heat risk variability, and identification of heat-risk areas not identified with the vector-based approach. Spatial smoothing with the Getis-Ord G(i) index produced heat risk hotspots from local to regional spatial scale. The approach is a framework for reducing spatial scale issues in future heat risk mapping, and for identifying heat risk hotspots at spatial scales ranging from the block-level to the municipality level.

Feasibility study using a Ni-Ti stent and electronic portal imaging to localize the prostate during radiotherapy.

PubMed

Carl, Jesper; Lund, Bente; Larsen, Erik Hoejkjaer; Nielsen, Jane

2006-02-01

A new method for localization of the prostate during external beam radiotherapy is presented. The method is based on insertion of a thermo-expandable Ni-Ti stent. The stent is originally developed for treatment of bladder outlet obstruction caused by benign hyperplasia. The radiological properties of the stent are used for precise prostate localization during treatment using electronic portal images. Patients referred for intended curative radiotherapy and having a length of their prostatic urethra in the range from 25 to 65 mm were included. Pairs of isocentric orthogonal portal images were used to determine the 3D position at eight different treatment sessions for each patient. Fourteen patients were enrolled in the study. The data obtained demonstrated that the stent position was representative of the prostate location. The stent may also improve delineation of the prostate GTV, and prevent obstruction of bladder outlet during treatment. Precision in localization of the stent was less than 1 mm. Random errors in stent position were left-right 1.6 mm, cranial-caudal 2.2 mm and anterior-posterior 3.2 mm. In four of 14 patients a dislocation of the stent to the bladder occurred. Dislocation only occurred in patients with length of prostatic urethra less than 40 mm. A new method for radiological high precision localization of the prostate during radiotherapy is presented. The method is based on insertion of a standard Ni-Ti thermo-expandable stent, designed for treatment of benign prostate hyperplasia.

In-situ shear stress indicator using heated strain gages at the flow boundary

NASA Astrophysics Data System (ADS)

Yeh, Chi-An; Yang, Fuling

2011-11-01

This work borrows the concept of hot-wire anemometry and sketch a technique that uses local heat transfer to infer the flow field and the corresponding stress. Conventional strain gages were mounted at the flow solid boundary as the heat source and acrylic boundary was chosen for its low thermal conductivity ensuring heat accumulation when a gage is energized. The gage would now work in slightly overheated state and its self-heating leads to an additional thermal strain. When exposed to a flow field, heat is brought away by local forced convection, resulting in deviations in gage signal from that developed in quiescent liquid. We have developed a facility to achieve synchronous gage measurements at different locations on a solid boundary. Three steady flow motions were considered: circular Couette flow, rectilinear uniform flow, and rectilinear oscillating flow. Preliminary tests show the gage reading does respond to the imposed flow through thermal effects and greater deviation was measured in flows of higher shear strain rates. The correlation between the gage signals and the imposed flow field is further examined by theoretical analysis. We also introduced a second solid boundary to the vicinity of the gage in the two rectilinear flows. The gage readings demonstrate rises in its magnitudes indicating wall amplification effect on the local shear strain, agreeing to the drag augmentation by a second solid boundary reported in many multiphase flow literatures.

Ion Heating During Local Helicity Injection Plasma Startup in the Pegasus ST

NASA Astrophysics Data System (ADS)

Burke, M. G.; Barr, J. L.; Bongard, M. W.; Fonck, R. J.; Hinson, E. T.; Perry, J. M.; Reusch, J. A.

2015-11-01

Plasmas in the Pegasus ST are initiated either through standard, MHD stable, inductive current drive or non-solenoidal local helicity injection (LHI) current drive with strong reconnection activity, providing a rich environment to study ion dynamics. During LHI discharges, a large amount of impurity ion heating has been observed, with the passively measured impurity Ti as high as 800 eV compared to Ti ~ 60 eV and Te ~ 175 eV during standard inductive current drive discharges. In addition, non-thermal ion velocity distributions are observed and appear to be strongest near the helicity injectors. The ion heating is hypothesized to be a result of large-scale magnetic reconnection activity, as the amount of heating scales with increasing fluctuation amplitude of the dominant, edge localized, n =1 MHD mode. An approximate temporal scaling of the heating with the amplitude of higher frequency magnetic fluctuations has also been observed, with large amounts of power spectral density present at several impurity ion cyclotron frequencies. Recent experiments have focused on investigating the impurity ion heating scaling with the ion charge to mass ratio as well as the reconnecting field strength. The ion charge to mass ratio was modified by observing different impurity charge states in similar LHI plasmas while the reconnecting field strength was modified by changing the amount of injected edge current. Work supported by US DOE grant DE-FG02-96ER54375.

Analysis of disturbances in a hypersonic boundary layer on a cone with heating/cooling of the nose tip

NASA Astrophysics Data System (ADS)

Bountin, Dmitry; Maslov, Anatoly; Gromyko, Yury

2018-05-01

Experimental results of the influence of local heating/cooling on the development of hypersonic boundary layer disturbances are reported. Local heating/cooling is applied at the cone nose tip. The experiments are carried out at the Mach number M = 5.95, stagnation temperature T0 = 360-418 K, and stagnation pressure P0 = 3.7-45 atm. The unit Reynolds number is varied in the interval Re1 = (4.5-63) × 106 m-1. The investigations are conducted in the boundary layer on a cone with an apex half-angle of 7° and varied bluntness radius of the nose tip [R = 0.03 (sharp nose), 0.75, and 1.5 mm] for different values of the local temperature factor. The nose tip is heated by an ohmic heater. Cooling is performed by supplying liquid nitrogen into the internal cavity of the model nose. A comparative analysis of pressure pulsation spectra on the cone surface is performed. It is demonstrated that heating/cooling in the case of a sharp cone leads to flow destabilization/stabilization. The opposite effect is observed for blunted cones: heating/cooling stabilizes/destabilizes the second-mode disturbances. This effect is enhanced by increasing the nose tip bluntness. All the observed effects vanish with distance downstream from the nose tip.

BLIMPK/Streamline Surface Catalytic Heating Predictions on the Space Shuttle Orbiter

NASA Technical Reports Server (NTRS)

Marichalar, Jeremiah J.; Rochelle, William C.; Kirk, Benjamin S.; Campbell, Charles H.

2006-01-01

This paper describes the results of an analysis of localized catalytic heating effects to the U.S. Space Shuttle Orbiter Thermal Protection System (TPS). The analysis applies to the High-temperature Reusable Surface Insulation (HRSI) on the lower fuselage and wing acreage, as well as the critical Reinforced Carbon-Carbon on the nose cap, chin panel and the wing leading edge. The object of the analysis was to use a modified two-layer approach to predict the catalytic heating effects on the Orbiter windward HRSI tile acreage, nose cap, and wing leading edge assuming localized highly catalytic or fully catalytic surfaces. The method incorporated the Boundary Layer Integral Matrix Procedure Kinetic (BLIMPK) code with streamline inputs from viscous Navier-Stokes solutions to produce heating rates for localized fully catalytic and highly catalytic surfaces as well as for nominal partially catalytic surfaces (either Reinforced Carbon-Carbon or Reaction Cured Glass) with temperature-dependent recombination coefficients. The highly catalytic heating results showed very good correlation with Orbiter Experiments STS-2, -3, and -5 centerline and STS-5 wing flight data for the HRSI tiles. Recommended catalytic heating factors were generated for use in future Shuttle missions in the event of quick-time analysis of damaged or repaired TPS areas during atmospheric reentry. The catalytic factors are presented along the streamlines as well as a function of stagnation enthalpy so they can be used for arbitrary trajectories.

Full melting of a two-dimensional complex plasma crystal triggered by localized pulsed laser heating

NASA Astrophysics Data System (ADS)

Couëdel, L.; Nosenko, V.; Rubin-Zuzic, M.; Zhdanov, S.; Elskens, Y.; Hall, T.; Ivlev, A. V.

2018-04-01

The full melting of a two-dimensional plasma crystal was induced in a principally stable monolayer by localized laser stimulation. Two distinct behaviors of the crystal after laser stimulation were observed depending on the amount of injected energy: (i) below a well-defined threshold, the laser melted area recrystallized; (ii) above the threshold, it expanded outwards in a similar fashion to mode-coupling instability-induced melting, rapidly destroying the crystalline order of the whole complex plasma monolayer. The reported experimental observations are due to the fluid mode-coupling instability, which can pump energy into the particle monolayer at a rate surpassing the heat transport and damping rates in the energetic localized melted spot, resulting in its further growth. This behavior exhibits remarkable similarities with impulsive spot heating in ordinary reactive matter.

Magnetohydrodynamics Carreau nanofluid flow over an inclined convective heated stretching cylinder with Joule heating

NASA Astrophysics Data System (ADS)

Khan, Imad; Shafquatullah; Malik, M. Y.; Hussain, Arif; Khan, Mair

Current work highlights the computational aspects of MHD Carreau nanofluid flow over an inclined stretching cylinder with convective boundary conditions and Joule heating. The mathematical modeling of physical problem yields nonlinear set of partial differential equations. A suitable scaling group of variables is employed on modeled equations to convert them into non-dimensional form. The integration scheme Runge-Kutta-Fehlberg on the behalf of shooting technique is utilized to solve attained set of equations. The interesting aspects of physical problem (linear momentum, energy and nanoparticles concentration) are elaborated under the different parametric conditions through graphical and tabular manners. Additionally, the quantities (local skin friction coefficient, local Nusselt number and local Sherwood number) which are responsible to dig out the physical phenomena in the vicinity of stretched surface are computed and delineated by varying controlling flow parameters.