Design of an Improved Heater Array to Measure Microscale Wall Heat Transfer

NASA Technical Reports Server (NTRS)

Kim, Jungho; Chng, Choon Ping; Kalkur, T. S.

1996-01-01

An improved array of microscale heaters is being developed to measure the heat transfer coefficient at many points underneath individual bubbles during boiling as a function of space and time. This heater array enables the local heat transfer from a surface during the bubble growth and departure process to be measured with very high temporal and spatial resolution, and should allow better understanding of the boiling heat transfer mechanisms by pin-pointing when and where in the bubble departure cycle large amounts of wall heat transfer occur. Such information can provide much needed data regarding the important heat transfer mechanisms during the bubble departure cycle, and can serve as benchmarks to validate many of the analytical and numerical models used to simulate boiling. The improvements to the heater array include using a silicon-on-quartz substrate to reduce thermal cross-talk between the heaters, decreased space between the heaters, increased pad sizes on the heaters, and progressive heater sizes. Some results using the present heater array are discussed.

Slow-light-enhanced energy efficiency for graphene microheaters on silicon photonic crystal waveguides

PubMed Central

Yan, Siqi; Zhu, Xiaolong; Frandsen, Lars Hagedorn; Xiao, Sanshui; Mortensen, N. Asger; Dong, Jianji; Ding, Yunhong

2017-01-01

Slow light has been widely utilized to obtain enhanced nonlinearities, enhanced spontaneous emissions and increased phase shifts owing to its ability to promote light–matter interactions. By incorporating a graphene on a slow-light silicon photonic crystal waveguide, here we experimentally demonstrate an energy-efficient graphene microheater with a tuning efficiency of 1.07 nmmW−1 and power consumption per free spectral range of 3.99 mW. The rise and decay times (10–90%) are only 750 and 525 ns, which, to the best of our knowledge, are the fastest reported response times for microheaters in silicon photonics. The corresponding figure of merit of the device is 2.543 nW s, one order of magnitude better than results reported in previous studies. The influence of the length and shape of the graphene heater to the tuning efficiency is further investigated, providing valuable guidelines for enhancing the tuning efficiency of the graphene microheater. PMID:28181531

Reconfigurable electro-optical directed-logic circuit using carrier-depletion micro-ring resonators.

PubMed

Qiu, Ciyuan; Gao, Weilu; Soref, Richard; Robinson, Jacob T; Xu, Qianfan

2014-12-15

Here we demonstrate a reconfigurable electro-optical directed-logic circuit based on a regular array of integrated optical switches. Each 1×1 optical switch consists of a micro-ring resonator with an embedded lateral p-n junction and a micro-heater. We achieve high-speed on-off switching by applying electrical logic signals to the p-n junction. We can configure the operation mode of each switch by thermal tuning the resonance wavelength. The result is an integrated optical circuit that can be reconfigured to perform any combinational logic operation. As a proof-of-principle, we fabricated a multi-spectral directed-logic circuit based on a fourfold array of switches and showed that this circuit can be reconfigured to perform arbitrary two-input logic functions with speeds up to 3  GB/s.

Design, Construction, and Qualification of a Microscale Heater Array for Use in Boiling Heat Transfer

NASA Technical Reports Server (NTRS)

Rule, T. D.; Kim, J.; Kalkur, T. S.

1998-01-01

Boiling heat transfer is an efficient means of heat transfer because a large amount of heat can be removed from a surface using a relatively small temperature difference between the surface and the bulk liquid. However, the mechanisms that govern boiling heat transfer are not well understood. Measurements of wall temperature and heat flux near the wall would add to the database of knowledge which is necessary to understand the mechanisms of nucleate boiling. A heater array has been developed which contains 96 heater elements within a 2.5 mm square area. The temperature of each heater element is held constant by an electronic control system similar to a hot-wire anemometer. The voltage that is being applied to each heater element can be measured and digitized using a high-speed A/D converter, and this digital information can be compiled into a series of heat-flux maps. Information for up to 10,000 heat flux maps can be obtained each second. The heater control system, the A/D system and the heater array construction are described in detail. Results are presented which show that this is an effective method of measuring the local heat flux during nucleate and transition boiling. Heat flux maps are obtained for pool boiling in FC-72 on a horizontal surface. Local heat flux variations are shown to be three to six times larger than variations in the spatially averaged heat flux.

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.

Self-gauged fiber-optic micro-heater with an operation temperature above 1000°C.

PubMed

Liu, Guigen; Sheng, Qiwen; Dam, Dustin; Hua, Jiong; Hou, Weilin; Han, Ming

2017-04-01

We report a fiber-optic micro-heater based on a miniature crystalline silicon Fabry-Perot interferometer (FPI) fusion spliced to the endface of a single-mode fiber. The silicon FPI, having a diameter of 100 μm and a length of 10 or 200 μm, is heated by a 980 nm laser diode guided through the lead-in fiber, leading to a localized hot spot with a temperature that can be conveniently tuned from the ambient temperature to >1000°C in air. In the meantime, using a white light system operating in the 1550 nm wavelength window where the silicon is transparent, the silicon FPI itself also serves as a thermometer with high resolution and high speed for convenient monitoring and precise control of the heater temperature. Due to its small size, high temperature capability, and easy operation, the micro-heater is attractive for applications in a variety of fields, such as biology, microfluidics system, mechanical engineering, and high-temperature optical sensing. As an example, the application of this micro-heater as a micro-boiler and micro-bubble generator has been demonstrated.

Cryogenic Multichannel Pressure Sensor With Electronic Scanning

NASA Technical Reports Server (NTRS)

Hopson, Purnell, Jr.; Chapman, John J.; Kruse, Nancy M. H.

1994-01-01

Array of pressure sensors operates reliably and repeatably over wide temperature range, extending from normal boiling point of water down to boiling point of nitrogen. Sensors accurate and repeat to within 0.1 percent. Operate for 12 months without need for recalibration. Array scanned electronically, sensor readings multiplexed and sent to desktop computer for processing and storage. Used to measure distributions of pressure in research on boundary layers at high Reynolds numbers, achieved by low temperatures.

Design and integration of an all-in-one biomicrofluidic chip

PubMed Central

Liu, Liyu; Cao, Wenbin; Wu, Jingbo; Wen, Weijia; Chang, Donald Choy; Sheng, Ping

2008-01-01

We demonstrate a highly integrated microfluidic chip with the function of DNA amplification. The integrated chip combines giant electrorheological-fluid actuated micromixer and micropump with a microheater array, all formed using soft lithography. Internal functional components are based on polydimethylsiloxane (PDMS) and silver∕carbon black-PDMS composites. The system has the advantages of small size with a high degree of integration, high polymerase chain reaction efficiency, digital control and simple fabrication at low cost. This integration approach shows promise for a broad range of applications in chemical synthesis and biological sensing∕analysis, as different components can be combined to target desired functionalities, with flexible designs of different microchips easily realizable through soft lithography. PMID:19693370

Copper vertical micro dendrite fin arrays and their superior boiling heat transfer capability

NASA Astrophysics Data System (ADS)

Wang, Ya-Qiao; Lyu, Shu-Shen; Luo, Jia-Li; Luo, Zhi-Yong; Fu, Yuan-Xiang; Heng, Yi; Zhang, Jian-Hui; Mo, Dong-Chuan

2017-11-01

Micro pin fin arrays have been widely used in electronic cooling, micro reactors, catalyst support, and wettability modification and so on, and a facile way to produce better micro pin fin arrays is demanded. Herein, a simple electrochemical method has been developed to fabricate copper vertical micro dendrite fin arrays (Cu-VMDFA) with controllable shapes, number density and height. High copper sulphate concentration is one key point to make the dendrite stand vertically. Besides, the applied current should rise at an appropriate rate to ensure the copper dendrite can grow vertically on its own. The Cu-VMDFA can significantly enhance the heat transfer coefficient by approximately twice compared to the plain copper surface. The Cu-VMDFA may be widely used in boiling heat transfer areas such as nuclear power plants, electronic cooling, heat exchangers, and so on.

Nanophotonic Trapping for Precise Manipulation of Biomolecular Arrays

PubMed Central

Soltani, Mohammad; Lin, Jun; Forties, Robert A.; Inman, James T.; Saraf, Summer N.; Fulbright, Robert M.; Lipson, Michal; Wang, Michelle D.

2014-01-01

Optical trapping is a powerful manipulation and measurement technique widely employed in the biological and materials sciences1–8. Miniaturizing optical trap instruments onto optofluidic platforms holds promise for high throughput lab-on-chip applications9–16. However, a persistent challenge with existing optofluidic devices has been controlled and precise manipulation of trapped particles. Here we report a new class of on-chip optical trapping devices. Using photonic interference functionalities, an array of stable, three-dimensional on-chip optical traps is formed at the antinodes of a standing-wave evanescent field on a nanophotonic waveguide. By employing the thermo-optic effect via integrated electric microheaters, the traps can be repositioned at high speed (~ 30 kHz) with nanometer precision. We demonstrate sorting and manipulation of individual DNA molecules. In conjunction with laminar flows and fluorescence, we also show precise control of the chemical environment of a sample with simultaneous monitoring. Such a controllable trapping device has the potential for high-throughput precision measurements on chip. PMID:24776649

Nanophotonic trapping for precise manipulation of biomolecular arrays.

PubMed

Soltani, Mohammad; Lin, Jun; Forties, Robert A; Inman, James T; Saraf, Summer N; Fulbright, Robert M; Lipson, Michal; Wang, Michelle D

2014-06-01

Optical trapping is a powerful manipulation and measurement technique widely used in the biological and materials sciences. Miniaturizing optical trap instruments onto optofluidic platforms holds promise for high-throughput lab-on-a-chip applications. However, a persistent challenge with existing optofluidic devices has been achieving controlled and precise manipulation of trapped particles. Here, we report a new class of on-chip optical trapping devices. Using photonic interference functionalities, an array of stable, three-dimensional on-chip optical traps is formed at the antinodes of a standing-wave evanescent field on a nanophotonic waveguide. By employing the thermo-optic effect via integrated electric microheaters, the traps can be repositioned at high speed (∼30 kHz) with nanometre precision. We demonstrate sorting and manipulation of individual DNA molecules. In conjunction with laminar flows and fluorescence, we also show precise control of the chemical environment of a sample with simultaneous monitoring. Such a controllable trapping device has the potential to achieve high-throughput precision measurements on chip.

Modeling and experimental investigation of an integrated optical microheater in silicon-on-insulator.

PubMed

Kaushal, Saket; Das, Bijoy Krishna

2016-04-10

A linear piecewise model has been formulated to analyze the performance of a metallic microheater integrated with single-mode waveguides (λ∼1550  nm) in silicon-on-insulator (SOI). The model has been used to evaluate integrated optical microheaters fabricated in a SOI substrate with 2 µm device layer thickness. The Fabry-Perot modulation technique has been used to extract the effective thermo-optic phase shift and response time. The effective thermal power budget of P_eff,π∼500  µW (out of actually consumed power P_π=1.1  mW) for a π phase shift and a switching time of τ∼9  µs, have been recorded for a typical Ti heater stripe of length L_H=50  µm, width W_H=2  µm, and thickness t_H∼150  nm, integrated with a Fabry-Perot waveguide cavity of length ∼20  mm. It has been shown that the performance of a heater improves (in terms of power budget) as the length of a microheater decreases. However, smaller heater size requires higher joule heating to obtain a desired phase shift, which is again found to be dependent on polarization of the guided mode because of thermal stress.

Understanding Graphics on a Scalable Latching Assistive Haptic Display Using a Shape Memory Polymer Membrane.

PubMed

Besse, Nadine; Rosset, Samuel; Zarate, Juan Jose; Ferrari, Elisabetta; Brayda, Luca; Shea, Herbert

2018-01-01

We present a fully latching and scalable 4 × 4 haptic display with 4 mm pitch, 5 s refresh time, 400 mN holding force, and 650 μm displacement per taxel. The display serves to convey dynamic graphical information to blind and visually impaired users. Combining significant holding force with high taxel density and large amplitude motion in a very compact overall form factor was made possible by exploiting the reversible, fast, hundred-fold change in the stiffness of a thin shape memory polymer (SMP) membrane when heated above its glass transition temperature. Local heating is produced using an addressable array of 3 mm in diameter stretchable microheaters patterned on the SMP. Each taxel is selectively and independently actuated by synchronizing the local Joule heating with a single pressure supply. Switching off the heating locks each taxel into its position (up or down), enabling holding any array configuration with zero power consumption. A 3D-printed pin array is mounted over the SMP membrane, providing the user with a smooth and room temperature array of movable pins to explore by touch. Perception tests were carried out with 24 blind users resulting in 70 percent correct pattern recognition over a 12-word tactile dictionary.

Fundamental Boiling and RP-1 Freezing Experiments

NASA Technical Reports Server (NTRS)

Goode, Brian

2002-01-01

The prestart thermal conditioning of the hardware in LOX (liquid oxygen) systems involve heat transfer between LOX and metal where boiling plays a large role. Information is easily found on nucleate boiling, maximum heat flux, minimum heat flux and film boiling for common fluids like water. After looking at these standard correlations it was felt more data was needed for the cool down side transition boiling for the LN2 and LOX. In particular interest is the film boiling values, the temperature at which transition begins and the slope as peak heat flux is approached. The ultimate goal is an array of boiling heat transfer coefficient as a function of surface temperature which can be used in the chilldown model of the feed system, engine and bleed system for X-34. The first experiment consisted of an actual MC-1 LOX Impeller which had been machined backwards, that was instrumented with 17 surface thermocouples and submerged in liquid nitrogen. The thermocouples were installed on metal thicknesses varying from the thin inducer to the thick hub.

Thermal Conductivity Measurement of Liquids by Using a Suspended Microheater

NASA Astrophysics Data System (ADS)

Oh, Dong-Wook

2017-10-01

In this paper, the traditional 3ω method is modified in order to measure the thermal conductivity of a droplet of liquid. The 3ω sensor is microfabricated using bulk silicon etching on a silicon wafer to form a microheater on a suspended bridge structure. The Si substrate of over 400 μ m thickness beneath the microheater is etched away so that the sample liquid can fill the gap created between the heater and the bottom boundary of the sensor. The frequency of the sinusoidal heating pulses that are generated from the heater is controlled such that the thermal penetration depth is much smaller than the thickness of the liquid layer. The temperature oscillation of the sample fluid is measured at the thin-film heater to calculate the thermal conductivity of the surrounding fluid. The thermal conductivity and measured values of the de-ionized water and ethanol show a good agreement with the theoretical values at room temperature.

Validation of MCNP: SPERT-D and BORAX-V fuel

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

Crawford, C.; Palmer, B.

1992-11-01

This report discusses critical experiments involving SPERT-D{sup 1,2} fuel elements and BORAX-V{sup 3-8} fuel which have been modeled and calculations performed with MCNP. MCNP is a Monte Carlo based transport code. For this study continuous-energy nuclear data from the ENDF/B-V cross section library was used. The SPERT-D experiments consisted of various arrays of fuel elements moderated and reflected with either water or a uranyl nitrate solution. Some SPERT-D experiments used cadmium as a fixed neutron poison, while others were poisoned with various concentrations of boron in the moderating/reflecting solution. ne BORAX-V experiments were arrays of either boiling fuel rod assembliesmore » or superheater assemblies, both types of arrays were moderated and reflected with water. In one boiling fuel experiment, two fuel rods were replaced with borated stainless steel poison rods.« less

Validation of MCNP: SPERT-D and BORAX-V fuel

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

Crawford, C.; Palmer, B.

1992-11-01

This report discusses critical experiments involving SPERT-D[sup 1,2] fuel elements and BORAX-V[sup 3-8] fuel which have been modeled and calculations performed with MCNP. MCNP is a Monte Carlo based transport code. For this study continuous-energy nuclear data from the ENDF/B-V cross section library was used. The SPERT-D experiments consisted of various arrays of fuel elements moderated and reflected with either water or a uranyl nitrate solution. Some SPERT-D experiments used cadmium as a fixed neutron poison, while others were poisoned with various concentrations of boron in the moderating/reflecting solution. ne BORAX-V experiments were arrays of either boiling fuel rod assembliesmore » or superheater assemblies, both types of arrays were moderated and reflected with water. In one boiling fuel experiment, two fuel rods were replaced with borated stainless steel poison rods.« less

Bubble Dynamics, Two-Phase Flow, and Boiling Heat Transfer in Microgravity

NASA Technical Reports Server (NTRS)

Chung, Jacob N.

1998-01-01

This report contains two independent sections. Part one is titled "Terrestrial and Microgravity Pool Boiling Heat Transfer and Critical heat flux phenomenon in an acoustic standing wave." Terrestrial and microgravity pool boiling heat transfer experiments were performed in the presence of a standing acoustic wave from a platinum wire resistance heater using degassed FC-72 Fluorinert liquid. The sound wave was created by driving a half wavelength resonator at a frequency of 10.15 kHz. Microgravity conditions were created using the 2.1 second drop tower on the campus of Washington State University. Burnout of the heater wire, often encountered with heat flux controlled systems, was avoided by using a constant temperature controller to regulate the heater wire temperature. The amplitude of the acoustic standing wave was increased from 28 kPa to over 70 kPa and these pressure measurements were made using a hydrophone fabricated with a small piezoelectric ceramic. Cavitation incurred during experiments at higher acoustic amplitudes contributed to the vapor bubble dynamics and heat transfer. The heater wire was positioned at three different locations within the acoustic field: the acoustic node, antinode, and halfway between these locations. Complete boiling curves are presented to show how the applied acoustic field enhanced boiling heat transfer and increased critical heat flux in microgravity and terrestrial environments. Video images provide information on the interaction between the vapor bubbles and the acoustic field. Part two is titled, "Design and qualification of a microscale heater array for use in boiling heat transfer." This part is summarized herein. Boiling heat transfer is an efficient means of heat transfer because a large amount of heat can be removed from a surface using a relatively small temperature difference between the surface and the bulk liquid. However, the mechanisms that govern boiling heat transfer are not well understood. Measurements of wall temperature and heat flux near the wall would add to the database of knowledge which is necessary to understand the mechanisms of nucleate boiling. A heater array has been developed which contains 96 heater elements within a 2.5 mm square area. The temperature of each heater element is held constant by an electronic control system similar to a hot-wire anemometer. The voltage that is being applied to each heater element can be measured and digitized using a high-speed Analog to Digital (A/D) converter, and this digital information can be compiled into a series of heat-flux maps. Information for up to 10,000 heat flux maps can be obtained each second. The heater control system, the A/D system and the heater array construction are described in detail. Results are presented which show that this is an effective method of measuring the local heat flux during nucleate and transition boiling. Heat flux maps are obtained for pool boiling in FC-72 on a horizontal surface. Local heat flux variations are shown to be three to six times larger than variations in the spatially averaged heat flux.

Optofluidic microvalve-on-a-chip with a surface plasmon-enhanced fiber optic microheater

PubMed Central

Zhang, Zhijian; Kusimo, Abisola; Yu, Miao

2014-01-01

We present an optofluidic microvalve utilizing an embedded, surface plasmon-enhanced fiber optic microheater. The fiber optic microheater is formed by depositing a titanium thin film on the roughened end-face of a silica optical fiber that serves as a waveguide to deliver laser light to the titanium film. The nanoscale roughness at the titanium-silica interface enables strong light absorption enhancement in the titanium film through excitation of localized surface plasmons as well as facilitates bubble nucleation. Our experimental results show that due to the unique design of the fiber optic heater, the threshold laser power required to generate a bubble is greatly reduced and the bubble growth rate is significantly increased. By using the microvalve, stable vapor bubble generation in the microchannel is demonstrated, which does not require complex optical focusing and alignment. The generated vapor bubble is shown to successfully block a liquid flow channel with a size of 125 μm × 125 μm and a flow rate of ∼10 μl/min at ∼120 mW laser power. PMID:25538813

Acoustically enhanced boiling heat transfer on a heated surface containing open microchannels

NASA Astrophysics Data System (ADS)

Boziuk, Thomas R.; Smith, Marc K.; Glezer, Ari

2011-11-01

Acoustic actuation is used to enhance boiling heat transfer on a submerged heated surface containing an array of open microchannels by controlling the formation and evolution of vapor bubbles and inhibiting the instability that leads to film boiling at the critical heat flux. The effect of actuation at millimeter and micrometer scales is investigated with emphasis on the behavior of bubble nucleation, growth, contact-line motion, condensation, and detachment. The results show that microchannels control the location of boiling and reduce the mean surface superheat. In addition, acoustic actuation increases the heat flux at a given surface temperature and leads to a significant increase in the critical heat flux, a reduction of the vapor mass above the surface, and the breakup of low-frequency vapor slug formation. Supported by ONR.

Microheater as an alternative to lasers for in-vitro fertilization applications

NASA Astrophysics Data System (ADS)

Palanker, Daniel V.; Turovets, Igor; Glazer, Rima; Reubinoff, Benjamin E.; Hilman, Dalia; Lewis, Aaron

1999-06-01

During the last decade various lasers have been applied to drilling of the micrometer-sized holes in the zona pellucida of oocytes for in-vitro fertilization applications. In this paper we describe an alternative approach to laser instrumentation based on microfabricated device capable of precise drilling of uniform holes in the zona pellucida of oocytes. This device consists of a thin (1 micrometer) film microheater built on the tip of glass capillary with a diameter varying between a few to a few tens of micrometers. Duration of the pulse of heat produced by this microheater determines the spatial confinement of the heat wave in the surrounding liquid medium. We have demonstrated that gradual microdrilling of the zona pellucida can be accomplished using a series of pulses with duration of about 300 microseconds when the microheater was held in contact with the zona pellucida. Pulse energy applied to 20 micrometer tip was about 4 (mu) J. In vitro development and hatching of 127 micromanipulated embryos was compared to 103 non-drilled control embryos. The technique was found to be highly efficient in creating round, uniform, well defined holes with a smooth wall surface, matching the size of the heating source. The architecture of the surrounding zona pellucida was unaffected by the drilling, as demonstrated by scanning electron microscopy. Micromanipulated embryos presented no signs of thermal damage under light microscopy. The rate of blastocyst formation and hatching was similar in the micromanipulated and control groups. Following further testing in animal models, this methodology may be used as a cost- effective alternative to laser-based instrumentation in clinical applications such as assisted hatching and embryo biopsy.

One-dimensional model of inertial pumping

NASA Astrophysics Data System (ADS)

Kornilovitch, Pavel E.; Govyadinov, Alexander N.; Markel, David P.; Torniainen, Erik D.

2013-02-01

A one-dimensional model of inertial pumping is introduced and solved. The pump is driven by a high-pressure vapor bubble generated by a microheater positioned asymmetrically in a microchannel. The bubble is approximated as a short-term impulse delivered to the two fluidic columns inside the channel. Fluid dynamics is described by a Newton-like equation with a variable mass, but without the mass derivative term. Because of smaller inertia, the short column refills the channel faster and accumulates a larger mechanical momentum. After bubble collapse the total fluid momentum is nonzero, resulting in a net flow. Two different versions of the model are analyzed in detail, analytically and numerically. In the symmetrical model, the pressure at the channel-reservoir connection plane is assumed constant, whereas in the asymmetrical model it is reduced by a Bernoulli term. For low and intermediate vapor bubble pressures, both models predict the existence of an optimal microheater location. The predicted net flow in the asymmetrical model is smaller by a factor of about 2. For unphysically large vapor pressures, the asymmetrical model predicts saturation of the effect, while in the symmetrical model net flow increases indefinitely. Pumping is reduced by nonzero viscosity, but to a different degree depending on the microheater location.

One-dimensional model of inertial pumping.

PubMed

Kornilovitch, Pavel E; Govyadinov, Alexander N; Markel, David P; Torniainen, Erik D

2013-02-01

A one-dimensional model of inertial pumping is introduced and solved. The pump is driven by a high-pressure vapor bubble generated by a microheater positioned asymmetrically in a microchannel. The bubble is approximated as a short-term impulse delivered to the two fluidic columns inside the channel. Fluid dynamics is described by a Newton-like equation with a variable mass, but without the mass derivative term. Because of smaller inertia, the short column refills the channel faster and accumulates a larger mechanical momentum. After bubble collapse the total fluid momentum is nonzero, resulting in a net flow. Two different versions of the model are analyzed in detail, analytically and numerically. In the symmetrical model, the pressure at the channel-reservoir connection plane is assumed constant, whereas in the asymmetrical model it is reduced by a Bernoulli term. For low and intermediate vapor bubble pressures, both models predict the existence of an optimal microheater location. The predicted net flow in the asymmetrical model is smaller by a factor of about 2. For unphysically large vapor pressures, the asymmetrical model predicts saturation of the effect, while in the symmetrical model net flow increases indefinitely. Pumping is reduced by nonzero viscosity, but to a different degree depending on the microheater location.

Capacitive sensing of droplets for microfluidic devices based on thermocapillary actuation.

PubMed

Chen, Jian Z; Darhuber, Anton A; Troian, Sandra M; Wagner, Sigurd

2004-10-01

The design and performance of a miniaturized coplanar capacitive sensor is presented whose electrode arrays can also function as resistive microheaters for thermocapillary actuation of liquid films and droplets. Optimal compromise between large capacitive signal and high spatial resolution is obtained for electrode widths comparable to the liquid film thickness measured, in agreement with supporting numerical simulations which include mutual capacitance effects. An interdigitated, variable width design, allowing for wider central electrodes, increases the capacitive signal for liquid structures with non-uniform height profiles. The capacitive resolution and time response of the current design is approximately 0.03 pF and 10 ms, respectively, which makes possible a number of sensing functions for nanoliter droplets. These include detection of droplet position, size, composition or percentage water uptake for hygroscopic liquids. Its rapid response time allows measurements of the rate of mass loss in evaporating droplets.

Selective formation of GaN-based nanorod heterostructures on soda-lime glass substrates by a local heating method.

PubMed

Hong, Young Joon; Kim, Yong-Jin; Jeon, Jong-Myeong; Kim, Miyoung; Choi, Jun Hee; Baik, Chan Wook; Kim, Sun Il; Park, Sung Soo; Kim, Jong Min; Yi, Gyu-Chul

2011-05-20

We report on the fabrication of high-quality GaN on soda-lime glass substrates, heretofore precluded by both the intolerance of soda-lime glass to the high temperatures required for III-nitride growth and the lack of an epitaxial relationship with amorphous glass. The difficulties were circumvented by heteroepitaxial coating of GaN on ZnO nanorods via a local microheating method. Metal-organic chemical vapor deposition of ZnO nanorods and GaN layers using the microheater arrays produced high-quality GaN/ZnO coaxial nanorod heterostructures at only the desired regions on the soda-lime glass substrates. High-resolution transmission electron microscopy examination of the coaxial nanorod heterostructures indicated the formation of an abrupt, semicoherent interface. Photoluminescence and cathodoluminescence spectroscopy was also applied to confirm the high optical quality of the coaxial nanorod heterostructures. Mg-doped GaN/ZnO coaxial nanorod heterostructure arrays, whose GaN shell layers were grown with various different magnesocene flow rates, were further investigated by using photoluminescence spectroscopy for the p-type doping characteristics. The suggested method for fabrication of III-nitrides on glass substrates signifies potentials for low-cost and large-size optoelectronic device applications.

MEMS-Based Gas Sensor Using PdO-Decorated TiO2 Thin Film for Highly Sensitive and Selective H2 Detection with Low Power Consumption

NASA Astrophysics Data System (ADS)

Kwak, Seungmin; Shim, Young-Seok; Yoo, Yong Kyoung; Lee, Jin-Hyung; Kim, Inho; Kim, Jinseok; Lee, Kyu Hyoung; Lee, Jeong Hoon

2018-03-01

We report a micromachined H2 sensor that is composed of a Pt micro-heater, low-stress insulating layer (SiO2/SiNx/SiO2), Pt-interdigitated electrodes, and gas sensing materials. Three types of Pt micro-heater are designed as function of electrode width, and their thermal properties are systematically analyzed by finite element modeling FEM with infrared camera. The power consumptions when the surface temperature reached 150, 200, 250, and 300 °C are calculated to approximately 33, 48, 67 and 85 mW, respectively. The response of the PdO nanoparticles-decorated TiO2 thin films to H2 is much higher than those of other gases such as CH4 and CO at 200 °C (48 mW). Further, the response time is reduced to approximately 3 s. The enhancement of gas sensing properties is related to well-designed micro-heater and catalytic effects of PdO nanoparticles such as electronic and chemical sensitization. These results suggest that the PdO nanoparticles-decorated TiO2 thin film, namely MEMS-based H2 sensors are very promising for use in IoT application to improve the quality of human's life.

MEMS-Based Gas Sensor Using PdO-Decorated TiO2 Thin Film for Highly Sensitive and Selective H2 Detection with Low Power Consumption

NASA Astrophysics Data System (ADS)

Kwak, Seungmin; Shim, Young-Seok; Yoo, Yong Kyoung; Lee, Jin-Hyung; Kim, Inho; Kim, Jinseok; Lee, Kyu Hyoung; Lee, Jeong Hoon

2018-05-01

We report a micromachined H2 sensor that is composed of a Pt micro-heater, low-stress insulating layer (SiO2/SiNx/SiO2), Pt-interdigitated electrodes, and gas sensing materials. Three types of Pt micro-heater are designed as function of electrode width, and their thermal properties are systematically analyzed by finite element modeling FEM with infrared camera. The power consumptions when the surface temperature reached 150, 200, 250, and 300 °C are calculated to approximately 33, 48, 67 and 85 mW, respectively. The response of the PdO nanoparticles-decorated TiO2 thin films to H2 is much higher than those of other gases such as CH4 and CO at 200 °C (48 mW). Further, the response time is reduced to approximately 3 s. The enhancement of gas sensing properties is related to well-designed micro-heater and catalytic effects of PdO nanoparticles such as electronic and chemical sensitization. These results suggest that the PdO nanoparticles-decorated TiO2 thin film, namely MEMS-based H2 sensors are very promising for use in IoT application to improve the quality of human's life.

Nonlinear numerical analysis and experimental testing for an electrothermal SU-8 microgripper with reduced out-of-plane displacement

NASA Astrophysics Data System (ADS)

Voicu, Rodica-Cristina; Zandi, Muaiyd Al; Müller, Raluca; Wang, Changhai

2017-11-01

This paper reports the results of numerical nonlinear electro-thermo-mechanical analysis and experimental testing of a polymeric microgripper designed using electrothermal actuators. The simulation work was carried out using a finite element method (FEM) and a commercial software (Coventorware 2014). The biocompatible SU-8 polymer was used as structural material for the fabrication of the microgripper. The metallic micro-heater was encapsulated in the polymeric actuation structures of the microgripper to reduce the undesirable out-of-plane displacement of the microgripper tips, and to electrically isolate the micro-heater, and to reduce the mechanical stress as well as to improve the thermal efficiency. The electro- thermo-mechanical analysis of the actuator considers the nonlinear temperature-dependent properties of the SU-8 polymer and the gold thin film layers used for the micro-heater fabrication. An optical characterisation of the microgripper based on an image tracking approach shows the thermal response and the good repeatability. The average deflection is ~11 µm for an actuation current of ~17 mA. The experimentally obtained tip deflection and the heater temperature at different currents are both shown to be in good agreement with the nonlinear electro-thermo-mechanical simulation results. Finally, we demonstrate the capability of the microgripper by capture and manipulation of cotton fibres.

Catalytic hydrogen sensing using microheated platinum nanoparticle-loaded graphene aerogel

DOE PAGES

Harley-Trochimczyk, Anna; Chang, Jiyoung; Zhou, Qin; ...

2014-10-02

We present that low power catalytic hydrogen sensors are fabricated by functionalizing low power polysilicon microheaters with platinum nanoparticle catalyst loaded in a high surface area graphene aerogel support. Fabrication and characterization of the polysilicon microheaters are described. The platinum nanoparticle-loaded graphene aerogel is characterized by transmission electron microscopy, scanning electron microscopy, and energy dispersive X-ray spectroscopy. Finally, the catalytic hydrogen sensors consume as little as 2.2 mW of power, have sensitivity of 1.6%/10,000 ppm hydrogen, a t90 response and recovery time of 0.97 s and 0.72 s, respectively, a lower detection limit of approximately 65 ppm, and negligible crossmore » sensitivity to methane, n-pentane, and diethylether.« less

Study on Fins' Effect of Boiling Flow in Millimeter Channel Heat Exchanger

NASA Astrophysics Data System (ADS)

Watanabe, Satoshi

2005-11-01

Recently, a lot of researches about compact heat exchangers with mini-channels have been carried out with the hope of obtaining a high-efficiency heat transfer, due to the higher ratio of surface area than existing heat exchangers. However, there are many uncertain phenomena in fields such as boiling flow in mini-channels. Thus, in order to understand the boiling flow in mini-channels to design high-efficiency heat exchangers, this work focused on the visualization measurement of boiling flow in a millimeter channel. A transparent acrylic channel (heat exchanger form), high-speed camera (2000 fps at 1024 x 1024 pixels), and halogen lamp (backup light) were used as the visualization system. The channel's depth is 2 mm, width is 30 mm, and length is 400 mm. In preparation for commercial use, two types of channels were experimented on: a fins type and a normal slit type (without fins). The fins are circular cylindrical obstacles (diameter is 5 mm) to promote heat transfer, set in a triangular array (distance between each center point is 10 mm). Especially in this work, boiling flow and heat transfer promotion in the millimeter channel heat exchanger with fins was evaluated using a high-speed camera.

Electro-optofluidics: achieving dynamic control on-chip

PubMed Central

Soltani, Mohammad; Inman, James T.; Lipson, Michal; Wang, Michelle D.

2012-01-01

A vital element in integrated optofluidics is dynamic tuning and precise control of photonic devices, especially when employing electronic techniques which are challenging to utilize in an aqueous environment. We overcome this challenge by introducing a new platform in which the photonic device is controlled using electro-optical phase tuning. The phase tuning is generated by the thermo-optic effect using an on-chip electric microheater located outside the fluidic channel, and is transmitted to the optofluidic device through optical waveguides. The microheater is compact, high-speed (> 18 kHz), and consumes low power (~mW). We demonstrate dynamic optical trapping control of nanoparticles by an optofluidic resonator. This novel electro-optofluidic platform allows the realization of high throughput optofluidic devices with switching, tuning, and reconfiguration capability, and promises new directions in optofluidics. PMID:23037380

Cryogenic Boil-Off Reduction System

NASA Astrophysics Data System (ADS)

Plachta, David W.; Guzik, Monica C.

2014-03-01

A computational model of the cryogenic boil-off reduction system being developed by NASA as part of the Cryogenic Propellant Storage and Transfer technology maturation project has been applied to a range of propellant storage tanks sizes for high-performing in-space cryogenic propulsion applications. This effort focuses on the scaling of multi-layer insulation (MLI), cryocoolers, broad area cooling shields, radiators, solar arrays, and tanks for liquid hydrogen propellant storage tanks ranging from 2 to 10 m in diameter. Component scaling equations were incorporated into the Cryogenic Analysis Tool, a spreadsheet-based tool used to perform system-level parametric studies. The primary addition to the evolution of this updated tool is the integration of a scaling method for reverse turbo-Brayton cycle cryocoolers, as well as the development and inclusion of Self-Supporting Multi-Layer Insulation. Mass, power, and sizing relationships are traded parametrically to establish the appropriate loiter period beyond which this boil-off reduction system application reduces mass. The projected benefit compares passive thermal control to active thermal control, where active thermal control is evaluated for reduced boil-off with a 90 K shield, zero boil-off with a single heat interception stage at the tank wall, and zero boil-off with a second interception stage at a 90 K shield. Parametric studies show a benefit over passive storage at loiter durations under one month, in addition to showing a benefit for two-stage zero boil-off in terms of reducing power and mass as compared to single stage zero boil-off. Furthermore, active cooling reduces the effect of varied multi-layer insulation performance, which, historically, has been shown to be significant.

Thermal Analysis on Cryogenic Liquid Hydrogen Tank on an Unmanned Aerial Vehicle System

NASA Technical Reports Server (NTRS)

Wang, Xiao-Yen; Harpster, George; Hunter, James

2007-01-01

Thermal analyses are performed on the liquid hydrogen (LH2) tank designed for an unmanned aerial vehicle (UAV) powered by solar arrays and a regenerative proton-exchange membrane (PEM) fuel cell. A 14-day cruise mission at a 65,000 ft altitude is considered. Thermal analysis provides the thermal loads on the tank system and the boiling-off rates of LH2. Different approaches are being considered to minimize the boiling-off rates of the LH2. It includes an evacuated multilayer insulation (MLI) versus aerogel insulation on the LH2 tank and aluminum versus stainless steel spacer rings between the inner and outer tank. The resulting boil-off rates of LH2 provided by the one-dimensional model and three-dimensional finite element analysis (FEA) on the tank system are presented and compared to validate the results of the three-dimensional FEA. It concludes that heat flux through penetrations by conduction is as significant as that through insulation around the tank. The tank system with MLI insulation and stainless steel spacer rings result in the lowest boiling-off rate of LH2.

Virus based Full Colour Pixels using a Microheater

NASA Astrophysics Data System (ADS)

Kim, Won-Geun; Kim, Kyujung; Ha, Sung-Hun; Song, Hyerin; Yu, Hyun-Woo; Kim, Chuntae; Kim, Jong-Man; Oh, Jin-Woo

2015-09-01

Mimicking natural structures has been received considerable attentions, and there have been a few practical advances. Tremendous efforts based on a self-assembly technique have been contributed to the development of the novel photonic structures which are mimicking nature’s inventions. We emulate the photonic structures from an origin of colour generation of mammalian skins and avian skin/feathers using M13 phage. The structures can be generated a full range of RGB colours that can be sensitively switched by temperature and substrate materials. Consequently, we developed an M13 phage-based temperature-dependent actively controllable colour pixels platform on a microheater chip. Given the simplicity of the fabrication process, the low voltage requirements and cycling stability, the virus colour pixels enable us to substitute for conventional colour pixels for the development of various implantable, wearable and flexible devices in future.

An Updated Zero Boil-Off Cryogenic Propellant Storage Analysis Applied to Upper Stages or Depots in a LEO Environment

NASA Technical Reports Server (NTRS)

Plachta, David; Kittel, Peter

2003-01-01

Previous efforts have shown the analytical benefits of zero boil-off (ZBO) cryogenic propellant storage in launch vehicle upper stages of Mars transfer vehicles for conceptual Mars Missions. However, recent NASA mission investigations have looked at a different and broad array of missions, including a variety of orbit transfer vehicle (OTV) propulsion concepts, some requiring cryogenic storage. For many of the missions, this vehicle will remain for long periods (greater than one week) in low earth orbit (LEO), a relatively warm thermal environment. Under this environment, and with an array of tank sizes and propellants, the performance of a ZBO cryogenic storage system is predicted and compared with a traditional, passive-only storage concept. The results show mass savings over traditional, passive-only cryogenic storage when mission durations are less than one week in LEO for oxygen, two weeks for methane, and roughly 2 months for LH2. Cryogenic xenon saves mass over passive storage almost immediately.

Experimental investigation on the thermal performance of Si micro-heat pipe with different cross-sections

NASA Astrophysics Data System (ADS)

Hamidnia, Mohammad; Luo, Yi; Wang, Xiaodong; Li, Congming

2017-10-01

Increasing component densities of the integrated circuit (IC) and packaging levels has led to thermal management problems. Si substrates with embedded micro-heat pipes (MHPs) couple good thermal characteristics and cost savings associated with IC batch processing. The thermal performance of MHP is intimately related to the cross-sectional geometry. Different cross-sections are designed in order to enhance the backflow of working fluid. In this experimental study, three different Si MHPs with same hydraulic diameter and various cross-sections are fabricated by micro-fabrication methods and tested under different conditions of fluid charge ratios. The results show that the trapezoidal MHP associated with rectangular artery which is charged with 40% of vapor chamber’s volume has the best thermal performance. This silicon-based MHP is a passive approach for thermal management, which could widen applications in the commercial electronics industry and LED lightings.

Increasing Boiling Heat Transfer using Low Conductivity Materials

PubMed Central

Mahamudur Rahman, Md; Pollack, Jordan; McCarthy, Matthew

2015-01-01

We report the counterintuitive mechanism of increasing boiling heat transfer by incorporating low-conductivity materials at the interface between the surface and fluid. By embedding an array of non-conductive lines into a high-conductivity substrate, in-plane variations in the local surface temperature are created. During boiling the surface temperature varies spatially across the substrate, alternating between high and low values, and promotes the organization of distinct liquid and vapor flows. By systematically tuning the peak-to-peak wavelength of this spatial temperature variation, a resonance-like effect is seen at a value equal to the capillary length of the fluid. Replacing ~18% of the surface with a non-conductive epoxy results in a greater than 5x increase in heat transfer rate at a given superheat temperature. This drastic and counterintuitive increase is shown to be due to optimized bubble dynamics, where ordered pathways allow for efficient removal of vapor and the return of replenishing liquid. The use of engineered thermal gradients represents a potentially disruptive approach to create high-efficiency and high-heat-flux boiling surfaces which are naturally insensitive to fouling and degradation as compared to other approaches. PMID:26281890

NASA's Spitzer Space Telescope's Operational Mission Experience

NASA Technical Reports Server (NTRS)

Wilson, Robert K.; Scott, Charles P.

2006-01-01

New Generation of Detector Arrays(100 to 10,000 Gain in Capability over Previous Infrared Space Missions). IRAC: 256 x 256 pixel arrays operating at 3.6 microns, 4.5 microns, 5.8 microns, 8.0 microns. MIPS: Photometer with 3 sets of arrays operating at 24 microns, 70 microns and 160 microns. 128 x 128; 32 x 32 and 2 x 20 arrays. Spectrometer with 50-100 micron capabilities. IRS: 4 Array (128x128 pixel) Spectrograph, 4 -40 microns. Warm Launch Architecture: All other Infrared Missions launched with both the telescope and scientific instrument payload within the cryostat or Dewar. Passive cooling used to cool outer shell to approx.40 K. Cryogenic Boil-off then cools telescope to required 5.5K. Earth Trailing Heliocentric Orbit: Increased observing efficiency, simplification of observation planning, removes earth as heat source.

Ten-channel InP-based large-scale photonic integrated transmitter fabricated by SAG technology

NASA Astrophysics Data System (ADS)

Zhang, Can; Zhu, Hongliang; Liang, Song; Cui, Xiao; Wang, Huitao; Zhao, Lingjuan; Wang, Wei

2014-12-01

A 10-channel InP-based large-scale photonic integrated transmitter was fabricated by selective area growth (SAG) technology combined with butt-joint regrowth (BJR) technology. The SAG technology was utilized to fabricate the electroabsorption modulated distributed feedback (DFB) laser (EML) arrays at the same time. The design of coplanar electrodes for electroabsorption modulator (EAM) was used for the flip-chip bonding package. The lasing wavelength of DFB laser could be tuned by the integrated micro-heater to match the ITU grids, which only needs one electrode pad. The average output power of each channel is 250 μW with an injection current of 200 mA. The static extinction ratios of the EAMs for 10 channels tested are ranged from 15 to 27 dB with a reverse bias of 6 V. The frequencies of 3 dB bandwidth of the chip for each channel are around 14 GHz. The novel design and simple fabrication process show its enormous potential in reducing the cost of large-scale photonic integrated circuit (LS-PIC) transmitter with high chip yields.

Microfluid oscillator based on thermocapillarity

NASA Astrophysics Data System (ADS)

Huang, Teng-chao; Shen, Yi-bing; Liu, Xu; Bai, Jian; Hou, Xiyun; Ye, Hui; Lou, Di

2004-12-01

A novel micro fluid oscillator with a boron diffused resistor is proposed in this paper. The actuation principle is based on the combination of Marangoni effect. The contemporary microfabrication technique enables us to fabricate microheater tiny enough to control temperature so quickly and precisely in micro length scale. The devices exhibiting the Marangoni effect in square channels were designed and fabricated from one silicon substrate and two quartz substrates. And the three substrates were aligned, bonded and packaged for testing. In this actuator there is a pair of micro-heaters to produce a thermal gradient along the slit. The driving wattage is about 0.1W and the resistors can make a temperature difference about 100 degrees during 0.1s with a pulsewidth of 20us for 0.1A current pulses. Then the movement is driven towards the lower temperature direction by the interfacial tension of the air-liquid interface. This micro fluid actuator can play important role in many liquid micro-systems such as in micromotor and micro valve.

Subcooled Pool Boiling Heat Transfer Mechanisms in Microgravity: Terrier-improved Orion Sounding Rocket Experiment

NASA Technical Reports Server (NTRS)

Kim, Jungho; Benton, John; Kucner, Robert

2000-01-01

A microscale heater array was used to study boiling in earth gravity and microgravity. The heater array consisted of 96 serpentine heaters on a quartz substrate. Each heater was 0.27 square millimeters. Electronic feedback loops kept each heater's temperature at a specified value. The University of Maryland constructed an experiment for the Terrier-Improved Orion sounding rocket that was delivered to NASA Wallops and flown. About 200 s of high quality microgravity and heat transfer data were obtained. The VCR malfunctioned, and no video was acquired. Subsequently, the test package was redesigned to fly on the KC-135 to obtain both data and video. The pressure was held at atmospheric pressure and the bulk temperature was about 20 C. The wall temperature was varied from 85 to 65 C. Results show that gravity has little effect on boiling heat transfer at wall superheats below 25 C, despite vast differences in bubble behavior between gravity levels. In microgravity, a large primary bubble was surrounded by smaller bubbles, which eventually merged with the primary bubble. This bubble was formed by smaller bubbles coalescing, but had a constant size for a given superheat, indicating a balance between evaporation at the base and condensation on the cap. Most of the heaters under the bubble indicated low heat transfer, suggesting dryout at those heaters. High heat transfer occurred at the contact line surrounding the primary bubble. Marangoni convection formed a "jet" of fluid into the bulk fluid that forced the bubble onto the heater.

Single-Crystalline UiO-67-Type Porous Network Stable to Boiling Water, Solvent Loss, and Oxidation.

PubMed

Wong, Yan-Lung; Yee, Ka-Kit; Hou, Yun-Long; Li, Jiaqian; Wang, Zuankai; Zeller, Matthias; Hunter, Allen D; Xu, Zhengtao

2018-06-04

With methylthio groups flanking the carboxyl groups, the 3,3',5,5'-tetrakis(methylthio)biphenyl dicarboxylate (TMBPD) linker forms a zirconium(IV) carboxylate porous framework featuring the topology of the UiO-67 prototype, i.e., with a face-centered-cubic array of the Zr 6 O 4 (OH) 4 clusters. Thioether functionalization proves valuable because the ZrTMBPD crystal is found to be exceptionally stable not only upon long-term exposure to air but also in boiling water and a broad range of pH conditions. The hydrophobicity of the metal-organic framework can also be tuned by simple H 2 O 2 oxidation, as illustrated in the water contact-angle measurement of the pristine and H 2 O 2 -treated ZrTMBPD solid.

Natural convection heat transfer for a staggered array of heated, horizontal cylinders within a rectangular enclosure

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

Triplett, C.E.

1996-12-01

This thesis presents the results of an experimental investigation of natural convection heat transfer in a staggered array of heated cylinders, oriented horizontally within a rectangular enclosure. The main purpose of this research was to extend the knowledge of heat transfer within enclosed bundles of spent nuclear fuel rods sealed within a shipping or storage container. This research extends Canaan`s investigation of an aligned array of heated cylinders that thermally simulated a boiling water reactor (BWR) spent fuel assembly sealed within a shipping or storage cask. The results are presented in terms of piecewise Nusselt-Rayleigh number correlations of the formmore » Nu = C(Ra){sup n}, where C and n are constants. Correlations are presented both for individual rods within the array and for the array as a whole. The correlations are based only on the convective component of the heat transfer. The radiative component was calculated with a finite-element code that used measured surface temperatures, rod array geometry, and measured surface emissivities as inputs. The correlation results are compared to Canaan`s aligned array results and to other studies of natural convection in horizontal tube arrays.« less

Novel development of the micro-tensile test at elevated temperature using a test structure with integrated micro-heater

NASA Astrophysics Data System (ADS)

Ang, W. C.; Kropelnicki, P.; Soe, Oak; Ling, J. H. L.; Randles, A. B.; Hum, A. J. W.; Tsai, J. M. L.; Tay, A. A. O.; Leong, K. C.; Tan, C. S.

2012-08-01

This paper describes the novel development of a micro-tensile testing method that allows testing at elevated temperatures. Instead of using a furnace, a titanium/platinum thin film micro-heater was fabricated on a conventional dog-bone-shaped test structure to heat up its gauge section locally. An infrared (IR) camera with 5 µm resolution was employed to verify the temperature uniformity across the gauge section of the test structure. With this micro-heater-integrated test structure, micro-tensile tests can be performed at elevated temperatures using any conventional tensile testing system without any major modification to the system. In this study, the tensile test of the single crystal silicon (SCS) thin film with (1 0 0) surface orientation and <1 1 0> tensile direction was performed at room temperature and elevated temperatures, up to 300 °C. Experimental results for Young's modulus as a function of temperature are presented. A micro-sized SCS film showed a low dependence of mechanical properties on temperature up to 300 °C.

Platinum Nanoparticle Loading of Boron Nitride Aerogel and Its Use as a Novel Material for Low-Power Catalytic Gas Sensing

DOE PAGES

Harley-Trochimczyk, Anna; Pham, Thang; Chang, Jiyoung; ...

2015-12-09

We report that a high-surface-area, highly crystalline boron nitride aerogel synthesized with nonhazardous reactants has been loaded with crystalline platinum nanoparticles to form a novel nanomaterial that exhibits many advantages for use in a catalytic gas sensing application. The platinum nanoparticle-loaded boron nitride aerogel integrated onto a microheater platform allows for calorimetric propane detection. The boron nitride aerogel exhibits thermal stability up to 900 °C and supports disperse platinum nanoparticles, with no sintering observed after 24 h of high-temperature testing. The high thermal conductivity and low density of the boron nitride aerogel result in an order of magnitude faster responsemore » and recovery times (<2 s) than reported on alumina support and allow for 10% duty cycling of the microheater with no loss in sensitivity. Lastly, the resulting 1.5 mW sensor power consumption is two orders of magnitude less than commercially available catalytic gas sensors and unlocks the potential for wireless, battery-powered catalytic gas sensing.« less

Fast-Response, Sensitivitive and Low-Powered Chemosensors by Fusing Nanostructured Porous Thin Film and IDEs-Microheater Chip

PubMed Central

Dai, Zhengfei; Xu, Lei; Duan, Guotao; Li, Tie; Zhang, Hongwen; Li, Yue; Wang, Yi; Wang, Yuelin; Cai, Weiping

2013-01-01

The chemiresistive thin film gas sensors with fast response, high sensitivity, low power consumption and mass-produced potency, have been expected for practical application. It requires both sensitive materials, especially exquisite nanomaterials, and efficient substrate chip for heating and electrical addressing. However, it is challenging to achieve repeatable microstructures across the films and low power consumption of substrate chip. Here we presented a new sensor structure via the fusion of metal-oxide nanoporous films and micro-electro-mechanical systems (MEMS)-based sensing chip. An interdigital-electrodes (IDEs) and microheater integrated MEMS structure is designed and employed as substrate chip to in-situ fabricate colloidal monolayer template-induced metal-oxide (egg. SnO2) nanoporous sensing films. This fused sensor demonstrates mW-level low power, ultrafast response (~1 s), and parts-per-billion lever detection for ethanol gas. Due to the controllable template strategy and mass-production potential, such micro/nano fused high-performance gas sensors will be next-generation key miniaturized/integrated devices for advanced practical applications. PMID:23591580

A laser pointer driven microheater for precise local heating and conditional gene regulation in vivo. Microheater driven gene regulation in zebrafish.

PubMed

Placinta, Mike; Shen, Meng-Chieh; Achermann, Marc; Karlstrom, Rolf O

2009-12-30

Tissue heating has been employed to study a variety of biological processes, including the study of genes that control embryonic development. Conditional regulation of gene expression is a particularly powerful approach for understanding gene function. One popular method for mis-expressing a gene of interest employs heat-inducible heat shock protein (hsp) promoters. Global heat shock of hsp-promoter-containing transgenic animals induces gene expression throughout all tissues, but does not allow for spatial control. Local heating allows for spatial control of hsp-promoter-driven transgenes, but methods for local heating are cumbersome and variably effective. We describe a simple, highly controllable, and versatile apparatus for heating biological tissue and other materials on the micron-scale. This microheater employs micron-scale fiber optics and uses an inexpensive laser-pointer as a power source. Optical fibers can be pulled on a standard electrode puller to produce tips of varying sizes that can then be used to reliably heat 20-100 mum targets. We demonstrate precise spatiotemporal control of hsp70l:GFP transgene expression in a variety of tissue types in zebrafish embryos and larvae. We also show how this system can be employed as part of a new method for lineage tracing that would greatly facilitate the study of organogenesis and tissue regulation at any time in the life cycle. This versatile and simple local heater has broad utility for the study of gene function and for lineage tracing. This system could be used to control hsp-driven gene expression in any organism simply by bringing the fiber optic tip in contact with the tissue of interest. Beyond these uses for the study of gene function, this device has wide-ranging utility in materials science and could easily be adapted for therapeutic purposes in humans.

Planar digital nanoliter dispensing system based on thermocapillary actuation.

PubMed

Darhuber, Anton A; Valentino, Joseph P; Troian, Sandra M

2010-04-21

We provide guidelines for the design and operation of a planar digital nanodispensing system based on thermocapillary actuation. Thin metallic microheaters embedded within a chemically patterned glass substrate are electronically activated to generate and control 2D surface temperature distributions which either arrest or trigger liquid flow and droplet formation on demand. This flow control is a consequence of the variation of a liquid's surface tension with temperature, which is used to draw liquid toward cooler regions of the supporting substrate. A liquid sample consisting of several microliters is placed on a flat rectangular supply cell defined by chemical patterning. Thermocapillary switches are then activated to extract a slender fluid filament from the cell and to divide the filament into an array of droplets whose position and volume are digitally controlled. Experimental results for the power required to extract a filament and to divide it into two or more droplets as a function of geometric and operating parameters are in excellent agreement with hydrodynamic simulations. The capability to dispense ultralow volumes onto a 2D substrate extends the functionality of microfluidic devices based on thermocapillary actuation previously shown effective in routing and mixing nanoliter liquid samples on glass or silicon substrates.

Material-Independent Nanotransfer onto a Flexible Substrate Using Mechanical-Interlocking Structure.

PubMed

Seo, Min-Ho; Choi, Seon-Jin; Park, Sang Hyun; Yoo, Jae-Young; Lim, Sung Kyu; Lee, Jae-Shin; Choi, Kwang-Wook; Jo, Min-Seung; Kim, Il-Doo; Yoon, Jun-Bo

2018-05-22

Nanowire-transfer technology has received much attention thanks to its capability to fabricate high-performance flexible nanodevices with high simplicity and throughput. However, it is still challenging to extend the conventional nanowire-transfer method to the fabrication of a wide range of devices since a chemical-adhesion-based nanowire-transfer mechanism is complex and time-consuming, hindering successful transfer of diverse nanowires made of various materials. Here, we introduce a material-independent mechanical-interlocking-based nanowire-transfer (MINT) method, fabricating ultralong and fully aligned nanowires on a large flexible substrate (2.5 × 2 cm 2 ) in a highly robust manner. For the material-independent nanotransfer, we developed a mechanics-based nanotransfer method, which employs a dry-removable amorphous carbon (a-C) sacrificial layer between a vacuum-deposited nanowire and the underlying master mold. The controlled etching of the sacrificial layer enables the formation of a mechanical-interlocking structure under the nanowire, facilitating peeling off of the nanowire from the master mold robustly and reliably. Using the developed MINT method, we successfully fabricated various metallic and semiconductor nanowire arrays on flexible substrates. We further demonstrated that the developed method is well suited to the reliable fabrication of highly flexible and high-performance nanoelectronic devices. As examples, a fully aligned gold (Au) microheater array exhibited high bending stability (10 6 cycling) and ultrafast (∼220 ms) heating operation up to ∼100 °C. An ultralong Au heater-embedded cuprous-oxide (Cu 2 O) nanowire chemical gas sensor showed significantly improved reversible reaction kinetics toward NO 2 with 10-fold enhancement in sensitivity at 100 °C.

Summary of Research 1998, Department of Mechanical Engineering.

DTIC Science & Technology

1999-08-01

thermoacoustic behavior in strong zero-mean oscillatory flows with potential application to the design of heat exchangers in thermoacoustic engines...important feature in the thermal characterization of microtubes , which are to be used in microheat exchangers . DoD KEY TECHNOLOGY AREA: Modeling and...Simulation KEYWORDS: Laminar Duct Flows, Convection and Conduction Heat Transfer, Axial Conduction, Micro- heat Exchang - ers DEVELOPMENT AND CALIBRATION

Towards the minimization of thermodynamic irreversibility in an electrically actuated microflow of a viscoelastic fluid under electrical double layer phenomenon

NASA Astrophysics Data System (ADS)

Sarma, Rajkumar; Jain, Manish; Mondal, Pranab Kumar

2017-10-01

We discuss the entropy generation minimization for electro-osmotic flow of a viscoelastic fluid through a parallel plate microchannel under the combined influences of interfacial slip and conjugate transport of heat. We use in this study the simplified Phan-Thien-Tanner model to describe the rheological behavior of the viscoelastic fluid. Using Navier's slip law and thermal boundary conditions of the third kind, we solve the transport equations analytically and evaluate the global entropy generation rate of the system. We examine the influential role of the following parameters on the entropy generation rate of the system, viz., the viscoelastic parameter (ɛDe2), Debye-Hückel parameter ( κ ¯ ) , channel wall thickness (δ), thermal conductivity of the wall (γ), Biot number (Bi), Peclet number (Pe), and axial temperature gradient (B). This investigation finally establishes the optimum values of the abovementioned parameters, leading to the minimum entropy generation of the system. We believe that results of this analysis could be helpful in optimizing the second-law performance of microscale thermal management devices, including the micro-heat exchangers, micro-reactors, and micro-heat pipes.

Nanowire-Assembled Hierarchical ZnCo2O4 Microstructure Integrated with a Low-Power Microheater for Highly Sensitive Formaldehyde Detection.

PubMed

Long, Hu; Harley-Trochimczyk, Anna; Cheng, Siyi; Hu, Hao; Chi, Won Seok; Rao, Ameya; Carraro, Carlo; Shi, Tielin; Tang, Zirong; Maboudian, Roya

2016-11-23

Nanowire-assembled 3D hierarchical ZnCo 2 O 4 microstructure is synthesized by a facile hydrothermal route and a subsequent annealing process. In comparison to simple nanowires, the resulting dandelion-like structure yields more open spaces between nanowires, which allow for better gas diffusion and provide more active sites for gas adsorption while maintaining good electrical conductivity. The hierarchical ZnCo 2 O 4 microstructure is integrated on a low-power microheater platform without using binders or conductive additives. The hierarchical structure of the ZnCo 2 O 4 sensing material provides reliable electrical connection across the sensing electrodes. The resulting sensor exhibits an ultralow detection limit of 3 ppb toward formaldehyde with fast response and recovery as well as good selectivity to CO, H 2 , and hydrocarbons such as n-pentane, propane, and CH 4 . The sensor only consumes ∼5.7 mW for continuous operation at 300 °C with good long-term stability. The excellent sensing performance of this hierarchical structure based sensor suggests the advantages of combining such structures with microfabricated heaters for practical low-power sensing applications.

Pool boiling on surfaces with mini-fins and micro-cavities

NASA Astrophysics Data System (ADS)

Pastuszko, Robert; Piasecka, Magdalena

2012-11-01

The experimental studies presented here focused on pool boiling heat transfer on mini-fin arrays, mini-fins with perforated covering and surfaces with micro-cavities. The experiments were carried out for water and fluorinert FC-72 at atmospheric pressure. Mini-fins of 0.5 and 1 mm in height were uniformly spaced on the base surface. The copper foil with holes of 0.1 mm in diameter (pitch 0.2/0.4 mm), sintered with the fin tips, formed a system of connected perpendicular and horizontal tunnels. The micro-cavities were obtained through spark erosion. The maximal depth of the craters of these cavities was 15 - 30 μm and depended on the parameters of the branding-pen settings. At medium and small heat fluxes, structures with mini-fins showed the best boiling heat transfer performance both for water and FC-72. At medium and high heat fluxes (above 70 kW/m2 for water and 25 kW/m2 for FC-72), surfaces with mini-fins without porous covering and micro-cavities produced the highest heat transfer coefficients. The surfaces obtained with spark erosion require a proper selection of geometrical parameters for particular liquids - smaller diameters of cavities are suitable for liquids with lower surface tension (FC-72).

NaK pool-boiler bench-scale receiver durability test: Test results and materials analysis

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

Andraka, C.E.; Goods, S.H.; Bradshaw, R.W.

1994-06-01

Pool-boiler reflux receivers have been considered as an alternative to heat pipes for the input of concentrated solar energy to Stirling-cycle engines in dish-Stirling electric generation systems. Pool boilers offer simplicity in design and fabrication. The operation of a full-scale pool-boiler receiver has been demonstrated for short periods of time. However, to generate cost-effective electricity, the receiver must operate Without significant maintenance for the entire system life, as much as 20 to 30 years. Long-term liquid-metal boiling stability and materials compatibility with refluxing NaK-78 is not known and must be determined for the pool boiler receiver. No boiling system hasmore » been demonstrated for a significant duration with the current porous boiling enhancement surface and materials. Therefore, it is necessary to simulate the full-scale pool boiler design as much as possible, including flux levels, materials, and operating cycles. On-sun testing is impractical because of the limited test time available. A test vessel was constructed with a porous boiling enhancement surface. The boiling surface consisted of a brazed stainless steel powder with about 50% porosity. The vessel was heated with a quartz lamp array providing about go W/CM2 peak incident thermal flux. The vessel was charged with NaK-78. This allows the elimination of costly electric preheating, both on this test and on fullscale receivers. The vessel was fabricated from Haynes 230 alloy. The vessel operated at 750{degrees}C around the clock, with a 1/2-hour shutdown cycle to ambient every 8 hours. The test completed 7500 hours of lamp-on operation time, and over 1000 startups from ambient. The test was terminated when a small leak in an Inconel 600 thermowell was detected. The test design and data are presented here. Metallurgical analysis of virgin and tested materials has begun, and initial results are also presented.« less

Development of an Efficient Micro-Heat Exchanger: The Integration of Design Processing and Testing

DTIC Science & Technology

2005-11-01

together at high temperatures and cooled to room temperature. Additionally, alumina and zirconia powders have a major difference in densification...efficient heat exchanger. The main problem that needed to be resolved was the fact that the zirconia powders shrink much more than alumina powder...been measured. Our measurement in dimensions verifies that zirconia powders shrink substantially more than alumina powder except CR-15 after final

Selective microrobot control using a thermally responsive microclamper for microparticle manipulation

NASA Astrophysics Data System (ADS)

Go, Gwangjun; Choi, Hyunchul; Jeong, Semi; Ko, Seong Young; Park, Jong-Oh; Park, Sukho

2016-03-01

Microparticle manipulation using a microrobot in an enclosed environment, such as a lab-on-a-chip, has been actively studied because an electromagnetic actuated microrobot can have accurate motility and wireless controllability. In most studies on electromagnetic actuated microrobots, only a single microrobot has been used to manipulate cells or microparticles. However, the use of a single microrobot can pose several limitations when performing multiple roles in microparticle manipulation. To overcome the limitations associated with using a single microrobot, we propose a new method for the control of multiple microrobots. Multiple microrobots can be controlled independently by an electromagnetic actuation system and multiple microclampers combined with microheaters. To select a specific microrobot among multiple microrobots, we propose a microclamper composed of a clamper structure using thermally responsive hydrogel and a microheater for controlling the microclamper. A fundamental test of the proposed microparticle manipulation system is performed by selecting a specific microrobot among multiple microrobots. Through the independent locomotion of multiple microrobots with U- and V-shaped tips, heterogeneous microparticle manipulation is demonstrated in the creation of a two-dimensional structure. In the future, our proposed multiple-microrobot system can be applied to tasks that are difficult to perform using a single microrobot, such as cell manipulation, cargo delivery, tissue assembly, and cloning.

Ordered molecular arrays as templates: A new approach to synthesis of mesoporous materials

NASA Astrophysics Data System (ADS)

Behrens, P.; Stucky, G.

There has been a growing interest in the extension of the microporous molecular sieve synthesis and applications to mesoscopic dimensions. Typical areas for the application of mesoscopic zeolite-type structures are in separation (e.g., protein separation and selective adsorption of large organic molecules from waste waters) and catalysis (e.g., processing of tar sand and of the high distillates of crude oils to valuable low-boiling products). Another is in the supramolecular assembly of molecular array and polymers for electronic and optical applications. In a new concept in the synthesis of porous material the templating agent is no longer a single, solvated, organic molecule or metal ion, but rather a self-assembled molecular array. This template leads to mesoporous materials with adjustable pore sizes between 16 and greater than 100 Angstrom, covering well the mesophorous range of greatest interest. The periodic arrangement of pores is very regular, and the pore size distribution measured by absorption is nearly as sharp as that of conventional zeolites.

Enhanced flow boiling in microchannels through integrating multiple micro-nozzles and reentry microcavities

NASA Astrophysics Data System (ADS)

Li, Wenming; Qu, Xiaopeng; Alam, Tamanna; Yang, Fanghao; Chang, Wei; Khan, Jamil; Li, Chen

2017-01-01

In a microchannel system, a higher mass velocity can lead to enhanced flow boiling performances, but at a cost of two-phase pressure drop. It is highly desirable to achieve a high heat transfer rate and critical heat flux (CHF) exceeding 1 kW/cm2 without elevating the pressure drop, particularly, at a reduced mass velocity. In this study, we developed a microchannel configuration that enables more efficient utilization of the coolant through integrating multiple microscale nozzles connected to auxiliary channels as well as microscale reentry cavities on sidewalls of main microchannels. We achieved a CHF of 1016 W/cm2 with a 50% less mass velocity, i.e., 680 kg/m2s, compared to the two-nozzle configuration developed in our previous studies. Two primary enhancement mechanisms are: (a) the enhanced global liquid supply by four evenly distributed micronozzles, particularly near the outlet region and (b) the effective management of local dryout by the capillary flow-induced sustainable thin liquid film resulting from an array of microscale cavities. A significantly improved heat transfer coefficient of 131 kW/m2 K at a mass velocity of 680 kg/m2s is attributed to the enhanced nucleate boiling, the established capillary/thin film evaporation, and the induced advection from the present microchannel configuration. All these significant enhancements have been achieved with a ˜55% lower two-phase pressure drop.

RUBI -a Reference mUltiscale Boiling Investigation for the Fluid Science Laboratory

NASA Astrophysics Data System (ADS)

Schweizer, Nils; Stelzer, Marco; Schoele-Schulz, Olaf; Picker, Gerold; Ranebo, Hans; Dettmann, Jan; Minster, Olivier; Toth, Balazs; Winter, Josef; Tadrist, Lounes; Stephan, Peter; Grassi, Walter; di Marco, Paolo; Colin, Catherine; Piero Celata, Gian; Thome, John; Kabov, Oleg

Boiling is a two-phase heat transfer process where large heat fluxes can be transferred with small driving temperature differences. The high performance of boiling makes the process very interesting for heat transfer applications and it is widely used in industry for example in power plants, refrigeration systems, and electronics cooling. Nevertheless, due to the large number of involved phenomena and their often highly dynamic nature a fundamental understanding and closed theoretical description is not yet accomplished. The design of systems incorporating the process is generally based on empirical correlations, which are commonly accompanied by large uncertainties and, thus, has to be verified by expensive test campaigns. Hence, strong efforts are currently made to develop applicable numerical tools for a reliable prediction of the boiling heat transfer performance and limits. In order to support and validate this development and, in particular as a precondition, to enhance the basic knowledge about boiling the comprehensive multi-scale experiment RUBI (Reference mUlti-scale Boiling Investigation) for the Fluid Science Laboratory on board the ISS is currently in preparation. The scientific objectives and requirements of RUBI have been defined by the members of the ESA topical team "Boiling and Multiphase Flow" and addresses fundamental aspects of boiling phenomena. The main objectives are the measurement of wall temperature and heat flux distribution underneath vapour bubbles with high spatial and tem-poral resolution by means of IR thermography accompanied by the synchronized high-speed observation of the bubble shapes. Furthermore, the fluid temperature in the vicinity and inside of the bubbles will be measured by a micro sensor array. Additional stimuli are the generation of an electric field above the heating surface and a shear flow created by a forced convection loop. The objective of these stimuli is to impose forces on the bubbles and investigate the resulting bubble behaviour such as bubble sliding on and detaching from the surface. The experiments benefits from the absence of vapour buoyancy and natural convection in the high quality and long-term microgravity of the ISS. Effects and phenomena like thermocapillary convection that are hardly observable in normal gravity conditions can be investigated. Clearly predefined conditions particularly of the thermal layer at the heating surface can be established without disturbances by natural convection. Vapour buoyancy as the main detaching force in normal gravity is missing. Hence, it is possible to study stationary, attached bubbles and alternative detaching forces. With RUBI a long history of boiling experiments is perpetuated that used microgravity as a tool for a deeper understanding of the fundamental phenomena. Several precursor experiments closely related to the RUBI project have already been conducted on parabolic flights. The subject of the paper is to provide an overview on the RUBI project, its scientific objectives and the corresponding experimental principle. The current design of the experiment container that is under development at ASTRIUM Space Transportation in Friedrichshafen will be introduced. Furthermore, results from the precursor experiments are presented. The industrial activities of the RUBI project are funded and the science team is supported by ESA.

Design of HIFU transducers to generate specific nonlinear ultrasound fields.

PubMed

Khokhlova, Vera A; Yuldashev, Petr V; Rosnitskiy, Pavel B; Maxwell, Adam D; Kreider, Wayne; Bailey, Michael R; Sapozhnikov, Oleg A

2016-01-01

Various clinical applications of high intensity focused ultrasound (HIFU) have different requirements on the pressure level and degree of nonlinear waveform distortion at the focus. Applications that utilize nonlinear waves with developed shocks are of growing interest, for example, for mechanical disintegration as well as for accelerated thermal ablation of tissue. In this work, an inverse problem of determining transducer parameters to enable formation of shocks with desired amplitude at the focus is solved. The solution was obtained by performing multiple direct simulations of the parabolic Khokhlov-Zabolotskaya-Kuznetsov (KZK) equation for various parameters of the source. It is shown that results obtained within the parabolic approximation can be used to describe the focal region of single element spherical sources as well as complex transducer arrays. It is also demonstrated that the focal pressure level at which fully developed shocks are formed mainly depends on the focusing angle of the source and only slightly depends on its aperture and operating frequency. Using the simulation results, a 256-element HIFU array operating at 1.5 MHz frequency was designed for a specific application of boiling-histotripsy that relies on the presence of 90-100 MPa shocks at the focus. The size of the array elements and focusing angle of the array were chosen to satisfy technical limitations on the intensity at the array elements and desired shock amplitudes in the focal waveform. Focus steering capabilities of the array were analysed using an open-source T-Array software developed at Moscow State University.

Design of HIFU Transducers to Generate Specific Nonlinear Ultrasound Fields

NASA Astrophysics Data System (ADS)

Khokhlova, Vera A.; Yuldashev, Petr V.; Rosnitskiy, Pavel B.; Maxwell, Adam D.; Kreider, Wayne; Bailey, Michael R.; Sapozhnikov, Oleg A.

Various clinical applications of high intensity focused ultrasound (HIFU) have different requirements on the pressure level and degree of nonlinear waveform distortion at the focus. Applications that utilize nonlinear waves with developed shocks are of growing interest, for example, for mechanical disintegration as well as for accelerated thermal ablation oftissue. In this work, an inverse problem of determining transducer parameters to enable formation of shockswith desired amplitude at the focus is solved. The solution was obtained by performing multipledirect simulations of the parabolic Khokhlov-Zabolotskaya-Kuznetsov (KZK) equation for various parameters of the source. It is shown that results obtained within the parabolic approximation can be used to describe the focal region of single element spherical sourcesas well as complex transducer arrays. It is also demonstrated that the focal pressure level at which fully developed shocksare formed mainly depends on the focusing angle of the source and only slightly depends on its aperture and operating frequency. Using the simulation results, a 256-element HIFU array operating at 1.5 MHz frequency was designed for a specific application of boiling-histotripsy that relies on the presence of 90-100 MPa shocks at the focus. The size of the array elements and focusing angle of the array were chosen to satisfy technical limitations on the intensity at the array elements and desired shock amplitudes in the focal waveform. Focus steering capabilities of the array were analysed using an open-source T-Array software developed at Moscow State University.

Fabrication of a micro-fluid gathering tool for the gastrointestinal juice sampling function of a versatile capsular endoscope.

PubMed

Koo, Kyo-In; Lee, Sangmin; Cho, Dong-il Dan

2011-01-01

This paper presents a micro-fluid gathering tool for a versatile capsular endoscope that employs a solid chemical propellant, azobisisobutyronitrile (AIBN). The proposed tool consists of a micro-heater, an AIBN matrix, a Venturi tube, a reservoir, an inlet, and an outlet. The micro-heater heats the AIBN matrix to be decomposed into by-products and nitrogen gas. This nitrogen gas generates negative pressure passing through the Venturi tube. The generated negative pressure inhales a target fluid from around the inlet into the reservoir. All the parts are designed to be embedded inside a cylindrical shape with a diameter of 17 mm and a height of 2.3 mm in order to integrate it into a versatile developmental capsular endoscope without any scaledown. Two sets of the proposed tools are fabricated and tested: one is made of polydimethylsiloxane (PDMS) and the other is made of polymethylmethacrylate (PMMA). In performance comparisons, the PDMS gathering tool can withstand a stronger pulling force, and the PMMA gathering tool requires a less negative pressure for inhaling the same target fluid. Due to the instant and full activation of the thin AIBN matrix, both types of gathering tool show analogous performance in the sample gathering evaluation. The gathered volume is approximately 1.57 μL using approximately 25.4 μL of AIBN compound.

Atomization of High-Viscosity Fluids for Aromatherapy Using Micro-heaters for Heterogeneous Bubble Nucleation

NASA Astrophysics Data System (ADS)

Law, Junhui; Kong, Ka Wai; Chan, Ho-Yin; Sun, Winston; Li, Wen Jung; Chau, Eric Boa Fung; Chan, George Kak Man

2017-01-01

The development of a novel lead-free microelectromechanical-system (MEMS)-based atomizer using the principle of thermal bubble actuation is presented. It is a low-cost, lead-free design that is environmentally friendly and harmless to humans. It has been tested to be applicable over a wide range of fluid viscosities, ranging from 1 cP (e.g., water) to 200 cP (e.g., oil-like fluid) at room temperature, a range that is difficult to achieve using ordinary atomizers. The results demonstrate that the average power consumption of the atomizer is approximately 1 W with an atomization rate of 0.1 to 0.3 mg of deionized (DI) water per cycle. The relationships between the micro-heater track width and the track gap, the size of the micro-cavities and the nucleation energy were studied to obtain an optimal atomizer design. The particle image velocimetry (PIV) results indicate that the diameter of the ejected droplets ranges from 30 to 90 μm with a speed of 20 to 340 mm/s. In addition, different modes of spraying are reported for the first time. It is envisioned that the successful development of this MEMS-based atomizing technology will revolutionize the existing market for atomizers and could also benefit different industries, particularly in applications involving viscous fluids.

Fabrication of a Micro-Fluid Gathering Tool for the Gastrointestinal Juice Sampling Function of a Versatile Capsular Endoscope

PubMed Central

Koo, Kyo-in; Lee, Sangmin; Cho, Dong-il Dan

2011-01-01

This paper presents a micro-fluid gathering tool for a versatile capsular endoscope that employs a solid chemical propellant, azobisisobutyronitrile (AIBN). The proposed tool consists of a micro-heater, an AIBN matrix, a Venturi tube, a reservoir, an inlet, and an outlet. The micro-heater heats the AIBN matrix to be decomposed into by-products and nitrogen gas. This nitrogen gas generates negative pressure passing through the Venturi tube. The generated negative pressure inhales a target fluid from around the inlet into the reservoir. All the parts are designed to be embedded inside a cylindrical shape with a diameter of 17 mm and a height of 2.3 mm in order to integrate it into a versatile developmental capsular endoscope without any scaledown. Two sets of the proposed tools are fabricated and tested: one is made of polydimethylsiloxane (PDMS) and the other is made of polymethylmethacrylate (PMMA). In performance comparisons, the PDMS gathering tool can withstand a stronger pulling force, and the PMMA gathering tool requires a less negative pressure for inhaling the same target fluid. Due to the instant and full activation of the thin AIBN matrix, both types of gathering tool show analogous performance in the sample gathering evaluation. The gathered volume is approximately 1.57 μL using approximately 25.4 μL of AIBN compound. PMID:22163997

A thermal microjet system with tapered micronozzles fabricated by inclined UV lithography for transdermal drug delivery

NASA Astrophysics Data System (ADS)

Yoon, Yong-Kyu; Park, Jung-Hwan; Lee, Jeong-Woo; Prausnitz, Mark R.; Allen, Mark G.

2011-02-01

Transdermal drug delivery can be enabled by various methods that increase the permeability of the skin's outer barrier of stratum corneum, including skin exposure to heat and chemical enhancers, such as ethanol. Combining these approaches for the first time, in this study we designed a microdevice consisting of an array of microchambers filled with ethanol that is vaporized using an integrated microheater and ejected through a micronozzle contacting the skin surface. In this way, we hypothesize that the hot ethanol vapor can increase skin permeability upon contacting the skin surface. The tapered micronozzle and the microchamber designed for this application were realized using proximity-mode inclined rotational ultraviolet lithography, which facilitates easy fabrication of complex three-dimensional structures, convenient integration with other functional layers, low fabrication cost, and mass production. The resulting device had a micronozzle with an orifice inner and outer diameter of 220 and 320 µm, respectively, and an extruded height of 250 µm. When the microchamber was filled with an ethanol gel and activated, the resulting ethanol vapor jet increased the permeability of human cadaver epidermis to a model compound, calcein, by approximately 17 times, which is attributed to thermal and chemical disruption of stratum corneum structure. This thermal microjet system can serve as a tool not only for transdermal drug delivery, but also for a variety of biomedical applications.

Effects of cooking and storage on residues of cyadox in chicken muscle.

PubMed

Zhang, Yanling; Wang, Yulian; Huang, Lingli; Chen, Dongmei; Tao, Yanfei; Yuan, Zonghui

2005-12-14

The aim of this study was to investigate the depletion of residues of cyadox in chicken muscle over time. The heat stabilities of cyadox (CYX) and its two metabolites, 1,4-bisdesoxycyadox (BDCYX) and quinoxaline-2-carboxylic acid (QCA), in water, cooking oil, and as incurred residues in chicken muscle were investigated. CYX was shown to be unstable with a half-life of about 37.7 min in 100 degrees C water. In hot cooking oil at 180 degrees C, all three compounds were unstable. CYX decreased quickly and was not able to be detected after heating for 2 min. Diode-array analysis of CYX standard solution in cooking oil indicated that a portion of BDCYX was formed. The residues of CYX and BDCYX deteriorated rapidly in frozen storage, while that of QCA changed slowly. Muscles containing CYX residues were boiled, microwaved, or fried for the specified times. During boiling, CYX and BDCYX were reduced 94% and 81% in 10 min, respectively. During microwave cooking, CYX and BDCYX were reduced 54% and 47% in 2.5 min, respectively. During frying, CYX and BDCYX were reduced 86% and 76%, respectively. No significant reduction of QCA was found for the three cooking methods. The half-lives of CYX residues in cooked chicken muscles were estimated as follows: 2.22 min for CYX and 4.44 min for BDCYX by boiling; 6.66 min for CYX and 9.36 min for BDCYX by microwaving.

Aluminum-based one- and two-dimensional micro fin array structures: high-throughput fabrication and heat transfer testing

NASA Astrophysics Data System (ADS)

Primeaux, Philip A.; Zhang, Bin; Zhang, Xiaoman; Miller, Jacob; Meng, W. J.; KC, Pratik; Moore, Arden L.

2017-02-01

Microscale fin array structures were replicated onto surfaces of aluminum 1100 and aluminum 6061 alloy (Al1100/Al6061) sheet metals through room-temperature instrumented roll molding. Aluminum-based micro fin arrays were replicated at room temperature, and the fabrication process is one with high throughput and low cost. One-dimensional (1D) micro fin arrays were made through one-pass rolling, while two-dimensional (2D) micro fin arrays were made by sequential 90° cross rolling with the same roller sleeve. For roll molding of 1D micro fins, fin heights greater than 600 µm were achieved and were shown to be proportional to the normal load force per feature width. At a given normal load force, the fin height was further shown to scale inversely with the hardness of the sheet metal. For sequential 90° cross rolling, morphologies of roll molded 2D micro fin arrays were examined, which provided clues to understand how plastic deformation occurred under cross rolling conditions. A series of pool boiling experiments on low profile Al micro fin array structures were performed within Novec 7100, a widely used commercial dielectric coolant. Results for both horizontal and vertical surface orientations show that roll molded Al micro fin arrays can increase heat flux at fixed surface temperature as compared to un-patterned Al sheet. The present results further suggest that many factors beyond just increased surface area can influence heat transfer performance, including surface finish and the important multiphase transport mechanisms in and around the fin geometry. These factors must also be considered when designing and optimizing micro fin array structures for heat transfer applications.

Cooking techniques improve the levels of bioactive compounds and antioxidant activity in kale and red cabbage.

PubMed

Murador, Daniella Carisa; Mercadante, Adriana Zerlotti; de Rosso, Veridiana Vera

2016-04-01

The aim of this study is to investigate the effects of different home cooking techniques (boiling, steaming, and stir-frying) in kale and red cabbage, on the levels of bioactive compounds (carotenoids, anthocyanins and phenolic compounds) determined by high-performance liquid chromatography coupled with photodiode array and mass spectrometry detectors (HPLC-DAD-MS(n)), and on the antioxidant activity evaluated by ABTS, ORAC and cellular antioxidant activity (CAA) assays. The steaming technique resulted in a significant increase in phenolic content in kale (86.1%; p<0.001) whereas in red cabbage it was significantly reduced (34.6%; p<0.001). In the kale, steaming resulted in significant increases in antioxidant activity levels in all of the evaluation methods. In the red cabbage, boiling resulted in a significant increase in antioxidant activity using the ABTS assay but resulted in a significant decrease using the ORAC assay. According to the CAA assay, the stir-fried sample displayed the highest levels of antioxidant activity. Copyright © 2015 Elsevier Ltd. All rights reserved.

Uniaxial alignment of triisopropylsilylethynyl pentacene via zone-casting technique.

PubMed

Su, Yajun; Gao, Xiang; Liu, Jiangang; Xing, Rubo; Han, Yanchun

2013-09-14

Uniaxially aligned triisopropylsilylethynyl pentacene (TIPS-pentacene) crystals over a large area were fabricated using zone-casting technique. The array of TIPS-pentacene displayed a high orientation degree with a dichroic ratio (DR) of 0.80. The crystals were arranged with c axis perpendicular to the substrate and the long axis of the ribbon corresponded to the a axis of TIPS-pentacene. The properties of the solutions and the processing parameters were shown to influence the formation of the oriented TIPS-pentacene crystalline array. Solvent with a low boiling point (such as chloroform) favoured the orientation of the ribbon-like crystals. The concentration of the solution should be appropriate, ensuring the crystallization velocity of TIPS-pentacene matching with the receding of the meniscus. Besides, we proved that the casting speed should be large enough to induce a sufficient concentration gradient. The orientation mechanism of TIPS-pentacene was attributed to a synergy of the ordered nuclei and a match between the crystallization velocity and the casting speed. Field effect transistors (FETs) based on the oriented TIPS-pentacene crystalline array showed a mobility of 0.67 cm(2) V(-1) s(-1).

Resonant optical device with a microheater

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

Lentine, Anthony L.; DeRose, Christopher

2017-04-04

A resonant photonic device is provided. The device comprises an optical waveguiding element, such as an optical resonator, that includes a diode junction region, two signal terminals configured to apply a bias voltage across the junction region, and a heater laterally separated from the optical waveguiding element. A semiconductor electrical barrier element is juxtaposed to the heater. A metallic strip is electrically and thermally connected at one end to a signal terminal of the optical waveguiding element and thermally connected at another end to the barrier element.

Design of HIFU transducers to generate specific nonlinear ultrasound fields

PubMed Central

Khokhlova, Vera A.; Yuldashev, Petr V.; Rosnitskiy, Pavel B.; Maxwell, Adam D.; Kreider, Wayne; Bailey, Michael R.; Sapozhnikov, Oleg A.

2017-01-01

Various clinical applications of high intensity focused ultrasound (HIFU) have different requirements on the pressure level and degree of nonlinear waveform distortion at the focus. Applications that utilize nonlinear waves with developed shocks are of growing interest, for example, for mechanical disintegration as well as for accelerated thermal ablation of tissue. In this work, an inverse problem of determining transducer parameters to enable formation of shocks with desired amplitude at the focus is solved. The solution was obtained by performing multiple direct simulations of the parabolic Khokhlov–Zabolotskaya–Kuznetsov (KZK) equation for various parameters of the source. It is shown that results obtained within the parabolic approximation can be used to describe the focal region of single element spherical sources as well as complex transducer arrays. It is also demonstrated that the focal pressure level at which fully developed shocks are formed mainly depends on the focusing angle of the source and only slightly depends on its aperture and operating frequency. Using the simulation results, a 256-element HIFU array operating at 1.5 MHz frequency was designed for a specific application of boiling-histotripsy that relies on the presence of 90–100 MPa shocks at the focus. The size of the array elements and focusing angle of the array were chosen to satisfy technical limitations on the intensity at the array elements and desired shock amplitudes in the focal waveform. Focus steering capabilities of the array were analysed using an open-source T-Array software developed at Moscow State University. PMID:28580038

An investigation of transition boiling mechanisms of subcooled water under forced convective conditions

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

Kwang-Won, Lee; Sang-Yong, Lee

1995-09-01

A mechanistic model for forced convective transition boiling has been developed to investigate transition boiling mechanisms and to predict transition boiling heat flux realistically. This model is based on a postulated multi-stage boiling process occurring during the passage time of the elongated vapor blanket specified at a critical heat flux (CHF) condition. Between the departure from nucleate boiling (DNB) and the departure from film boiling (DFB) points, the boiling heat transfer is established through three boiling stages, namely, the macrolayer evaporation and dryout governed by nucleate boiling in a thin liquid film and the unstable film boiling characterized by themore » frequent touches of the interface and the heated wall. The total heat transfer rates after the DNB is weighted by the time fractions of each stage, which are defined as the ratio of each stage duration to the vapor blanket passage time. The model predictions are compared with some available experimental transition boiling data. The parametric effects of pressure, mass flux, inlet subcooling on the transition boiling heat transfer are also investigated. From these comparisons, it can be seen that this model can identify the crucial mechanisms of forced convective transition boiling, and that the transition boiling heat fluxes including the maximum heat flux and the minimum film boiling heat flux are well predicted at low qualities/high pressures near 10 bar. In future, this model will be improved in the unstable film boiling stage and generalized for high quality and low pressure situations.« less

Lattice Boltzmann modeling of boiling heat transfer: The boiling curve and the effects of wettability

DOE PAGES

Li, Q.; Kang, Q. J.; Francois, M. M.; ...

2015-03-03

A hybrid thermal lattice Boltzmann (LB) model is presented to simulate thermal multiphase flows with phase change based on an improved pseudopotential LB approach (Li et al., 2013). The present model does not suffer from the spurious term caused by the forcing-term effect, which was encountered in some previous thermal LB models for liquid–vapor phase change. Using the model, the liquid–vapor boiling process is simulated. The boiling curve together with the three boiling stages (nucleate boiling, transition boiling, and film boiling) is numerically reproduced in the LB community for the first time. The numerical results show that the basic featuresmore » and the fundamental characteristics of boiling heat transfer are well captured, such as the severe fluctuation of transient heat flux in the transition boiling and the feature that the maximum heat transfer coefficient lies at a lower wall superheat than that of the maximum heat flux. Moreover, the effects of the heating surface wettability on boiling heat transfer are investigated. It is found that an increase in contact angle promotes the onset of boiling but reduces the critical heat flux, and makes the boiling process enter into the film boiling regime at a lower wall superheat, which is consistent with the findings from experimental studies.« less

Micro-incubator for bacterial biosensing applications

NASA Astrophysics Data System (ADS)

Clasen, Estine; Land, Kevin; Joubert, Trudi-Heleen

2016-02-01

The presence of Escherichia coli (E. coli ) is a commonly used indicator micro-organism to determine whether water is safe for human consumption.1 This paper discusses the design of a micro-incubator that can be applied to concentrate bacteria prior to environmental water quality screening tests. High sensitivity and rapid test time is essential and there is a great need for these tests to be implemented on-site without the use of a laboratory infrastructure. In the light of these requirements, a mobile micro-incubator was designed, manufactured and characterised. A polydimethylsiloxane (PDMS) receptacle has been designed to house the 1-5 ml cell culture sample.2 A nano-silver printed electronics micro-heater has been designed to incubate the bacterial sample, with an array of temperature sensors implemented to accurately measure the sample temperature at various locations in the cell culture well. The micro-incubator limits the incubation temperature range to 37+/-3 °C in order to ensure near optimal growth of the bacteria at all times.3 The incubation time is adjustable between 30 minutes and 9 hours with a maximum rise time of 15 minutes to reach the set-point temperature. The surface area of the printed nano silver heating element is 500 mm2. Electrical and COMSOL Multiphysics simulations are included in order to give insight on micro-incubator temperature control. The design and characterization of this micro-incubator allows for further research in biosensing applications.

Real-time Implementation of a Dual-Mode Ultrasound Array System: In Vivo Results

PubMed Central

Casper, Andrew J.; Liu, Dalong; Ballard, John R.; Ebbini, Emad S.

2013-01-01

A real-time dual-mode ultrasound array (DMUA) system for imaging and therapy is described. The system utilizes a concave (40-mm radius of curvature) 3.5 MHz, 32 element array and modular multi-channel transmitter/receiver. It is capable of operating in a variety of imaging and therapy modes (on transmit) and continuous receive on all array elements even during high-power operation. A signal chain consisting of field-programmable gate arrays (FPGA) and graphical processing units (GPU) is used to enable real-time, software-defined beamforming and image formation. Imaging data, from quality assurance phantoms as well as in vivo small and large animal models, are presented and discussed. Corresponding images obtained using a temporally-synchronized and spatially-aligned diagnostic probe confirm the DMUA’s ability to form anatomically-correct images with sufficient contrast in an extended field of view (FOV) around its geometric center. In addition, high frame rate DMUA data also demonstrate the feasibility of detection and localization of echo changes indicative of cavitation and/or tissue boiling during HIFU exposures with 45 – 50 dB dynamic range. The results also show that the axial and lateral resolution of the DMUA are consistent with its fnumber and bandwidth with well behaved speckle cell characteristics. These results point the way to a theranostic DMUA system capable of quantitative imaging of tissue property changes with high specificity to lesion formation using focused ultrasound. PMID:23708766

Real-time implementation of a dual-mode ultrasound array system: in vivo results.

PubMed

Casper, Andrew J; Liu, Dalong; Ballard, John R; Ebbini, Emad S

2013-10-01

A real-time dual-mode ultrasound array (DMUA) system for imaging and therapy is described. The system utilizes a concave (40-mm radius of curvature) 3.5 MHz, 32 element array, and modular multichannel transmitter/receiver. The system is capable of operating in a variety of imaging and therapy modes (on transmit) and continuous receive on all array elements even during high-power operation. A signal chain consisting of field-programmable gate arrays and graphical processing units is used to enable real time, software-defined beamforming and image formation. Imaging data, from quality assurance phantoms as well as in vivo small- and large-animal models, are presented and discussed. Corresponding images obtained using a temporally-synchronized and spatially-aligned diagnostic probe confirm the DMUA's ability to form anatomically-correct images with sufficient contrast in an extended field of view around its geometric center. In addition, high-frame rate DMUA data also demonstrate the feasibility of detection and localization of echo changes indicative of cavitation and/or tissue boiling during high-intensity focused ultrasound exposures with 45-50 dB dynamic range. The results also show that the axial and lateral resolution of the DMUA are consistent with its f(number) and bandwidth with well-behaved speckle cell characteristics. These results point the way to a theranostic DMUA system capable of quantitative imaging of tissue property changes with high specificity to lesion formation using focused ultrasound.

A high-sensitivity magnetocardiography system with a divided gradiometer array inside a low boil-off Dewar

NASA Astrophysics Data System (ADS)

Lee, Y. H.; Yu, K. K.; Kim, J. M.; Kwon, H.; Kim, K.

2009-11-01

We fabricated a low-noise 64-channel first-order axial gradiometer system for measuring magnetocardiography (MCG) signals. The key technical features of the system are the compact structure of the gradiometer, division of the sensor array plate, direct mounting of the sensor plates into the Dewar bottom, reduced neck diameter of the liquid He Dewar, and compact readout electronics. To make the refill interval of liquid He longer, the distance between the compensation coil of the gradiometer and the input coil pads of the superconducting quantum interference device (SQUID) was reduced to 20 mm. By using direct ultrasonic bonding of Nb wires between the pickup coil wires and input coil pads, the superconductive connection structure became simple. The baseline of the first-order gradiometer is 70 mm, a little longer than for typical conventional axial gradiometers, to provide a larger signal amplitude for deep sources. The 64-channel gradiometer array consists of four blocks, and each block is fixed separately onto the bottom of the Dewar. The neck diameter of the He Dewar (192 mm) is smaller than the bottom diameter (280 mm) in which the gradiometers are distributed. The average boil-off rate of the Dewar is 3 l per day when the 64-channel system is in operation every day. Double relaxation oscillation SQUIDs (DROSs) having large flux-to-voltage transfer coefficients were used to operate SQUIDs via compact electronics. The magnetically shielded room (MSR) has a wall thickness of 80 mm, and consists of two layers of permalloy and one layer of aluminum. When the 64-channel system was installed inside the MSR, the field noise level of the system was about 3.5 fTrms Hz-1/2 at 100 Hz. MCG measurements with high signal quality were done successfully using the developed system. In addition to the parameter analysis method, we developed software for the three-dimensional imaging of the myocardial current on a realistic image of the heart based on the anatomical image of the torso.

Fluid-elastic instability in tube arrays subjected to air-water and steam-water cross-flow

NASA Astrophysics Data System (ADS)

Mitra, D.; Dhir, V. K.; Catton, I.

2009-10-01

Flow induced vibrations in heat exchanger tubes have led to numerous accidents and economic losses in the past. Efforts have been made to systematically study the cause of these vibrations and develop remedial design criteria for their avoidance. In this research, experiments were systematically carried out with air-water and steam-water cross-flow over horizontal tubes. A normal square tube array of pitch-to-diameter ratio of 1.4 was used in the experiments. The tubes were suspended from piano wires and strain gauges were used to measure the vibrations. Tubes made of aluminum; stainless steel and brass were systematically tested by maintaining approximately the same stiffness in the tube-wire systems. Instability was clearly seen in single phase and two-phase flow and the critical flow velocity was found to be proportional to tube mass. The present study shows that fully flexible arrays become unstable at a lower flow velocity when compared to a single flexible tube surrounded by rigid tubes. It is also found that tubes are more stable in steam-water flow as compared to air-water flow. Nucleate boiling on the tube surface is also found to have a stabilizing effect on fluid-elastic instability.

Contrast-enhanced ultrasound imaging and in vivo circulatory kinetics with low-boiling-point nanoscale phase-change perfluorocarbon agents.

PubMed

Sheeran, Paul S; Rojas, Juan D; Puett, Connor; Hjelmquist, Jordan; Arena, Christopher B; Dayton, Paul A

2015-03-01

Many studies have explored phase-change contrast agents (PCCAs) that can be vaporized by an ultrasonic pulse to form microbubbles for ultrasound imaging and therapy. However, few investigations have been published on the utility and characteristics of PCCAs as contrast agents in vivo. In this study, we examine the properties of low-boiling-point nanoscale PCCAs evaluated in vivo and compare data with those for conventional microbubbles with respect to contrast generation and circulation properties. To do this, we develop a custom pulse sequence to vaporize and image PCCAs using the Verasonics research platform and a clinical array transducer. Results indicate that droplets can produce contrast enhancement similar to that of microbubbles (7.29 to 18.24 dB over baseline, depending on formulation) and can be designed to circulate for as much as 3.3 times longer than microbubbles. This study also reports for the first time the ability to capture contrast washout kinetics of the target organ as a measure of vascular perfusion. Copyright © 2015 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.

Atmospheric Pressure Effects on Cryogenic Storage Tank Boil-Off

NASA Technical Reports Server (NTRS)

Sass, J. P.; Frontier, C. R.

2007-01-01

The Cryogenics Test Laboratory (CTL) at the Kennedy Space Center (KSC) routinely utilizes cryostat test hardware to evaluate comparative and absolute thermal conductivities of a wide array of insulation systems. The test method is based on measurement of the flow rate of gas evolved due to evaporative boil-off of a cryogenic liquid. The gas flow rate typically stabilizes after a period of a couple of hours to a couple of days, depending upon the test setup. The stable flow rate value is then used to calculate the thermal conductivity for the insulation system being tested. The latest set of identical cryostats, 1,000-L spherical tanks, exhibited different behavior. On a macro level, the flow rate did stabilize after a couple of days; however the stable flow rate was oscillatory with peak to peak amplitude of up to 25 percent of the nominal value. The period of the oscillation was consistently 12 hours. The source of the oscillation has been traced to variations in atmospheric pressure due to atmospheric tides similar to oceanic tides. This paper will present analysis of this phenomenon, including a calculation that explains why other cryostats are not affected by it.

Vapor bubble evolution on a heated surface containing open microchannels

NASA Astrophysics Data System (ADS)

Forster, Christopher J.; Glezer, Ari; Smith, Marc K.

2011-11-01

Power electronics require cooling technologies capable of high heat fluxes at or below the operating temperatures of these devices. Boiling heat transfer is an effective choice for such cooling, but it is limited by the critical heat flux (CHF), which is typically near 125 W/cm2 for pool boiling of water on a flat plate at standard pressure and gravity. One method of increasing CHF is to incorporate an array of microchannels into the heated surface. Microchannels have been experimentally shown to improve CHF, and the goal of this study is to determine the primary mechanisms associated with the microchannels that allow for the increased CHF. While the use of various microstructures is not new, the emphasis of previous work has been on heat transfer aspects, as opposed to the fluid dynamics inside and in the vicinity of the microchannels. This work considers the non-isothermal fluid motion during bubble growth and departure by varying channel geometry, spacing, and heat flux input using a level-set method including vaporization and condensation. These results and the study of the underlying mechanisms will aid in the design optimization of microchannel-based cooling devices. Supported by ONR.

Boiling of the interface between two immiscible liquids below the bulk boiling temperatures of both components.

PubMed

Pimenova, Anastasiya V; Goldobin, Denis S

2014-11-01

We consider the problem of boiling of the direct contact of two immiscible liquids. An intense vapour formation at such a direct contact is possible below the bulk boiling points of both components, meaning an effective decrease of the boiling temperature of the system. Although the phenomenon is known in science and widely employed in technology, the direct contact boiling process was thoroughly studied (both experimentally and theoretically) only for the case where one of liquids is becoming heated above its bulk boiling point. On the contrary, we address the case where both liquids remain below their bulk boiling points. In this paper we construct the theoretical description of the boiling process and discuss the actualisation of the case we consider for real systems.

Universality of oscillating boiling in Leidenfrost transition

NASA Astrophysics Data System (ADS)

Tran, Tuan; Khavari, Mohammad

2017-11-01

The Leidenfrost transition leads a boiling system to the boiling crisis, a state in which the liquid loses contact with the heated surface due to excessive vapor generation. Here, using experiments of liquid droplets boiling on a heated surface, we report a new phenomenon, termed oscillating boiling, at the Leidenfrost transition. We show that oscillating boiling results from the competition between two effects: separation of liquid from the heated surface due to localized boiling, and rewetting. We argue theoretically that the Leidenfrost transition can be predicted based on its link with the oscillating boiling phenomenon, and verify the prediction experimentally for various liquids. This work was funded by Nanyang Technological University and A*STAR, Singapore.

21 CFR 872.6710 - Boiling water sterilizer.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Boiling water sterilizer. 872.6710 Section 872...) MEDICAL DEVICES DENTAL DEVICES Miscellaneous Devices § 872.6710 Boiling water sterilizer. (a) Identification. A boiling water sterilizer is an AC-powered device that consists of a container for boiling water...

21 CFR 872.6710 - Boiling water sterilizer.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Boiling water sterilizer. 872.6710 Section 872...) MEDICAL DEVICES DENTAL DEVICES Miscellaneous Devices § 872.6710 Boiling water sterilizer. (a) Identification. A boiling water sterilizer is an AC-powered device that consists of a container for boiling water...

21 CFR 872.6710 - Boiling water sterilizer.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Boiling water sterilizer. 872.6710 Section 872...) MEDICAL DEVICES DENTAL DEVICES Miscellaneous Devices § 872.6710 Boiling water sterilizer. (a) Identification. A boiling water sterilizer is an AC-powered device that consists of a container for boiling water...

21 CFR 872.6710 - Boiling water sterilizer.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Boiling water sterilizer. 872.6710 Section 872...) MEDICAL DEVICES DENTAL DEVICES Miscellaneous Devices § 872.6710 Boiling water sterilizer. (a) Identification. A boiling water sterilizer is an AC-powered device that consists of a container for boiling water...

Secondary pool boiling effects

NASA Astrophysics Data System (ADS)

Kruse, C.; Tsubaki, A.; Zuhlke, C.; Anderson, T.; Alexander, D.; Gogos, G.; Ndao, S.

2016-02-01

A pool boiling phenomenon referred to as secondary boiling effects is discussed. Based on the experimental trends, a mechanism is proposed that identifies the parameters that lead to this phenomenon. Secondary boiling effects refer to a distinct decrease in the wall superheat temperature near the critical heat flux due to a significant increase in the heat transfer coefficient. Recent pool boiling heat transfer experiments using femtosecond laser processed Inconel, stainless steel, and copper multiscale surfaces consistently displayed secondary boiling effects, which were found to be a result of both temperature drop along the microstructures and nucleation characteristic length scales. The temperature drop is a function of microstructure height and thermal conductivity. An increased microstructure height and a decreased thermal conductivity result in a significant temperature drop along the microstructures. This temperature drop becomes more pronounced at higher heat fluxes and along with the right nucleation characteristic length scales results in a change of the boiling dynamics. Nucleation spreads from the bottom of the microstructure valleys to the top of the microstructures, resulting in a decreased surface superheat with an increasing heat flux. This decrease in the wall superheat at higher heat fluxes is reflected by a "hook back" of the traditional boiling curve and is thus referred to as secondary boiling effects. In addition, a boiling hysteresis during increasing and decreasing heat flux develops due to the secondary boiling effects. This hysteresis further validates the existence of secondary boiling effects.

Optimizing the Combination of Smoking and Boiling on Quality of Korean Traditional Boiled Loin (M. longissimus dorsi)

PubMed Central

Choi, Yun-Sang; Kim, Hyun-Wook; Kim, Young-Boong; Kim, Cheon-Jei

2015-01-01

The combined effects of smoking and boiling on the proximate composition, technological quality traits, shear force, and sensory characteristics of the Korean traditional boiled loin were studied. Cooking loss, processing loss, and shear force were lower in the smoked/boiled samples than those in the control (without smoking treatment) (p<0.05). The results showed that the boiled loin samples between the control and treatment did not differ significantly in protein, fat, or ash contents, or pH values (p>0.05). The treated samples had higher score for overall acceptability than the control (p<0.05). Thus, these results show that the Korean traditional boiled loin treated with smoking for 60 min before boiling had improved physicochemical properties and sensory characteristics. PMID:26761822

Heat Transfer Performances of Pool Boiling on Metal-Graphite Composite Surfaces

NASA Technical Reports Server (NTRS)

Zhang, Nengli; Chao, David F.; Yang, Wen-Jei

2000-01-01

Nucleate boiling, especially near the critical heat flux (CHF), can provide excellent economy along with high efficiency of heat transfer. However, the performance of nucleate boiling may deteriorate in a reduced gravity environment and the nucleate boiling usually has a potentially dangerous characteristic in CHF regime. That is, any slight overload can result in burnout of the boiling surface because the heat transfer will suddenly move into the film-boiling regime. Therefore, enhancement of nucleate boiling heat transfer becomes more important in reduced gravity environments. Enhancing nucleate boiling and critical heat flux can be reached using micro-configured metal-graphite composites as the boiling surface. Thermocapillary force induced by temperature difference between the graphite-fiber tips and the metal matrix, which is independent of gravity, will play an important role in bubble detachment. Thus boiling heat transfer performance does not deteriorate in a reduced-gravity environment. Based on the existing experimental data, and a two-tier theoretical model, correlation formulas are derived for nucleate boiling on the copper-graphite and aluminum-graphite composite surfaces, in both the isolated and coalesced bubble regimes. Experimental studies were performed on nucleate pool boiling of pentane on cooper-graphite (Cu-Gr) and aluminum-graphite (Al-Gr) composite surfaces with various fiber volume concentrations for heat fluxes up to 35 W per square centimeter. It is revealed that a significant enhancement in boiling heat transfer performance on the composite surfaces is achieved, due to the presence of micro-graphite fibers embedded in the matrix. The onset of nucleate boiling (the isolated bubble regime) occurs at wall superheat of about 10 C for the Cu-Gr surface and 15 C for the Al-Gr surface, much lower than their respective pure metal surfaces. Transition from an isolated bubble regime to a coalesced bubble regime in boiling occurs at a superheat of about 14 C on Cu-Gr surface and 19 C on Al-Gr surface.

Biological cell controllable patch-clamp microchip

NASA Astrophysics Data System (ADS)

Penmetsa, Siva; Nagrajan, Krithika; Gong, Zhongcheng; Mills, David; Que, Long

2010-12-01

A patch-clamp (PC) microchip with cell sorting and positioning functions is reported, which can avoid drawbacks of random cell selection or positioning for a PC microchip. The cell sorting and positioning are enabled by air bubble (AB) actuators. AB actuators are pneumatic actuators, in which air pressure is generated by microheaters within sealed microchambers. The sorting, positioning, and capturing of 3T3 cells by this type of microchip have been demonstrated. Using human breast cancer cells MDA-MB-231 as the model, experiments have been demonstrated by this microchip as a label-free technical platform for real-time monitoring of the cell viability.

Coal liquefaction process with increased naphtha yields

DOEpatents

Ryan, Daniel F.

1986-01-01

An improved process for liquefying solid carbonaceous materials wherein the solid carbonaceous material is slurried with a suitable solvent and then subjected to liquefaction at elevated temperature and pressure to produce a normally gaseous product, a normally liquid product and a normally solid product. The normally liquid product is further separated into a naphtha boiling range product, a solvent boiling range product and a vacuum gas-oil boiling range product. At least a portion of the solvent boiling-range product and the vacuum gas-oil boiling range product are then combined and passed to a hydrotreater where the mixture is hydrotreated at relatively severe hydrotreating conditions and the liquid product from the hydrotreater then passed to a catalytic cracker. In the catalytic cracker, the hydrotreater effluent is converted partially to a naphtha boiling range product and to a solvent boiling range product. The naphtha boiling range product is added to the naphtha boiling range product from coal liquefaction to thereby significantly increase the production of naphtha boiling range materials. At least a portion of the solvent boiling range product, on the other hand, is separately hydrogenated and used as solvent for the liquefaction. Use of this material as at least a portion of the solvent significantly reduces the amount of saturated materials in said solvent.

40 CFR 180.1056 - Boiled linseed oil; exemption from requirement of tolerance.

Code of Federal Regulations, 2010 CFR

2010-07-01

... “boiled linseed oil.” This exemption is limited to use on rice before edible parts form. [46 FR 33270... 40 Protection of Environment 23 2010-07-01 2010-07-01 false Boiled linseed oil; exemption from... From Tolerances § 180.1056 Boiled linseed oil; exemption from requirement of tolerance. Boiled linseed...

Pool Boiling Experiment Has Five Successful Flights

NASA Technical Reports Server (NTRS)

Chiaramonte, Fran

1997-01-01

The Pool Boiling Experiment (PBE) is designed to improve understanding of the fundamental mechanisms that constitute nucleate pool boiling. Nucleate pool boiling is a process wherein a stagnant pool of liquid is in contact with a surface that can supply heat to the liquid. If the liquid absorbs enough heat, a vapor bubble can be formed. This process occurs when a pot of water boils. On Earth, gravity tends to remove the vapor bubble from the heating surface because it is dominated by buoyant convection. In the orbiting space shuttle, however, buoyant convection has much less of an effect because the forces of gravity are very small. The Pool Boiling Experiment was initiated to provide insight into this nucleate boiling process, which has many earthbound applications in steamgeneration power plants, petroleum plants, and other chemical plants. In addition, by using the test fluid R-113, the Pool Boiling Experiment can provide some basic understanding of the boiling behavior of cryogenic fluids without the large cost of an experiment using an actual cryogen.

New Folklore about Water.

ERIC Educational Resources Information Center

LeMaire, Peter; Waiveris, Charles

1995-01-01

Describes experiments designed to investigate the cooling rate of microwave-boiled water as compared to that of stove-boiled water. Concludes that within experimental limits, microwave-boiled water and stove-boiled water cool at the same rate. (JRH)

The plumbing of Old Faithful Geyser revealed by hydrothermal tremor

NASA Astrophysics Data System (ADS)

Vandemeulebrouck, J.; Roux, P.; Cros, E.

2013-05-01

Faithful Geyser in Yellowstone National Park (USA) has attracted numerous scientific investigations for over two centuries to better understand its geological structure, the physics of its eruptions, and the controls of its intermittency. Using data acquired with a seismic array in 1992, we track the sources of hydrothermal tremor produced by boiling and cavitation inside the geyser. The location of seismic sources identifies a previously unknown lateral cavity at 15 m below the surface, on the SW side of the vent, and connected to the conduit. This reservoir is activated at the beginning of each geyser eruption cycle and plays a major role in the oscillatory behavior of the water level in the conduit before each eruption.

Boiling incipience and convective boiling of neon and nitrogen

NASA Technical Reports Server (NTRS)

Papell, S. S.; Hendricks, R. C.

1977-01-01

Forced convection and subcooled boiling heat transfer data for liquid nitrogen and liquid neon were obtained in support of a design study for a 30 tesla cryomagnet cooled by forced convection of liquid neon. This design precludes nucleate boiling in the flow channels as they are too small to handle vapor flow. Consequently, it was necessary to determine boiling incipience under the operating conditions of the magnet system. The cryogen data obtained over a range of system pressures, fluid flow rates, and applied heat fluxes were used to develop correlations for predicting boiling incipience and convective boiling heat transfer coefficients in uniformly heated flow channels. The accuracy of the correlating equations was then evaluated. A technique was also developed to calculate the position of boiling incipience in a uniformly heated flow channel. Comparisons made with the experimental data showed a prediction accuracy of plus or minus 15 percent

Subcooled forced convection boiling of trichlorotrifluoroethane

NASA Technical Reports Server (NTRS)

Dougall, R. S.; Panian, D. J.

1972-01-01

Experimental heat-transfer data were obtained for the forced-convection boiling of trichlorotrifluoroethane (R-113 or Freon-113) in a vertical annular test annular test section. The 97 data points obtained covered heat transfer by forced convection, local boiling, and fully-developed boiling. Correlating methods were obtained which accurately predicted the heat flux as a function of wall superheat (boiling curve) over the range of parameters studied.

A review on boiling heat transfer enhancement with nanofluids

PubMed Central

2011-01-01

There has been increasing interest of late in nanofluid boiling and its use in heat transfer enhancement. This article covers recent advances in the last decade by researchers in both pool boiling and convective boiling applications, with nanofluids as the working fluid. The available data in the literature is reviewed in terms of enhancements, and degradations in the nucleate boiling heat transfer and critical heat flux. Conflicting data have been presented in the literature on the effect that nanofluids have on the boiling heat-transfer coefficient; however, almost all researchers have noted an enhancement in the critical heat flux during nanofluid boiling. Several researchers have observed nanoparticle deposition at the heater surface, which they have related back to the critical heat flux enhancement. PMID:21711794

Physical quality of Simental Ongole crossbred silverside meat at various boiling times

NASA Astrophysics Data System (ADS)

Riyanto, J.; Cahyadi, M.; Guntari, W. S.

2018-03-01

This study aims to determine the physical quality of silverside beef meat at various boiling times. Samples that have been used are the back thigh or silverside meat. Treatment of boiling meat included TR (meat without boiled), R15 (boiled 15 minutes), and R30 (boiled for 30 minutes). The experimental design using Completely Randomized Design with 3 replications. Each replication was done in triple physical quality test. Determination of physical quality was performed at the Livestock Industry and Processing Laboratory at Sebelas Maret University Surakarta and the Meat Technology Laboratory at the Faculty of Animal Husbandry of Gadjah Mada University. The result of variance analysis showed that boiling affect cooking loss (P≥0.05) and but did not affect (P≤0,05) pH, water holding capacity and meat tenderness. The conclusions of the study showed that boiling for 15 minutes and 30 minutes decreased the cooking loss of Simental Ongole Crossbred silverside meat. Meat physical quality of pH, water holding capacity and the value of tenderness is not affected by boiling for 15 and 30 minutes.

Explosive Boiling at Very Low Heat Fluxes: A Microgravity Phenomenon

NASA Technical Reports Server (NTRS)

Hasan, M. M.; Lin, C. S.; Knoll, R. H.; Bentz, M. D.

1993-01-01

The paper presents experimental observations of explosive boiling from a large (relative to bubble sizes) flat heating surface at very low heat fluxes in microgravity. The explosive boiling is characterized as either a rapid growth of vapor mass over the entire heating surface due to the flashing of superheated liquid or a violent boiling spread following the appearance of single bubbles on the heating surface. Pool boiling data with saturated Freon 113 was obtained in the microgravity environment of the space shuttle. The unique features of the experimental results are the sustainability of high liquid superheat for long periods and the occurrence of explosive boiling at low heat fluxes (0.2 to 1.2 kW/sq m). For a heat flux of 1.0 kW/sq m a wall superheat of 17.9 degrees C was attained in ten minutes of heating. This was followed by an explosive boiling accompanied with a pressure spike and a violent bulk liquid motion. However, at this heat flux the vapor blanketing the heating surface could not be sustained. Stable nucleate boiling continued following the explosive boiling.

Nano-enabled paper humidity sensor for mobile based point-of-care lung function monitoring.

PubMed

Bhattacharjee, Mitradip; Nemade, Harshal B; Bandyopadhyay, Dipankar

2017-08-15

The frequency of breathing and peak flow rate of exhaled air are necessary parameters to detect chronic obstructive pulmonary diseases (COPDs) such as asthma, bronchitis, or pneumonia. We developed a lung function monitoring point-of-care-testing device (LFM-POCT) consisting of mouthpiece, paper-based humidity sensor, micro-heater, and real-time monitoring unit. Fabrication of a mouthpiece of optimal length ensured that the exhaled air was focused on the humidity-sensor. The resistive relative humidity sensor was developed using a filter paper coated with nanoparticles, which could easily follow the frequency and peak flow rate of the human breathing. Adsorption followed by condensation of the water molecules of the humid air on the paper-sensor during the forced exhalation reduced the electrical resistance of the sensor, which was converted to an electrical signal for sensing. A micro-heater composed of a copper-coil embedded in a polymer matrix helped in maintaining an optimal temperature on the sensor surface. Thus, water condensed on the sensor surface only during forcible breathing and the sensor recovered rapidly after the exhalation was complete by rapid desorption of water molecules from the sensor surface. Two types of real-time monitoring units were integrated into the device based on light emitting diodes (LEDs) and smart phones. The LED based unit displayed the diseased, critical, and fit conditions of the lungs by flashing LEDs of different colors. In comparison, for the mobile based monitoring unit, an application was developed employing an open source software, which established a wireless connectivity with the LFM-POCT device to perform the tests. Copyright © 2017 Elsevier B.V. All rights reserved.

Enhanced spectroscopic gas sensors using in-situ grown carbon nanotubes

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

De Luca, A.; Cole, M. T.; Milne, W. I.

2015-05-11

In this letter, we present a fully complementary-metal-oxide-semiconductor (CMOS) compatible microelectromechanical system thermopile infrared (IR) detector employing vertically aligned multi-walled carbon nanotubes (CNT) as an advanced nano-engineered radiation absorbing material. The detector was fabricated using a commercial silicon-on-insulator (SOI) process with tungsten metallization, comprising a silicon thermopile and a tungsten resistive micro-heater, both embedded within a dielectric membrane formed by a deep-reactive ion etch following CMOS processing. In-situ CNT growth on the device was achieved by direct thermal chemical vapour deposition using the integrated micro-heater as a micro-reactor. The growth of the CNT absorption layer was verified through scanning electronmore » microscopy, transmission electron microscopy, and Raman spectroscopy. The functional effects of the nanostructured ad-layer were assessed by comparing CNT-coated thermopiles to uncoated thermopiles. Fourier transform IR spectroscopy showed that the radiation absorbing properties of the CNT adlayer significantly enhanced the absorptivity, compared with the uncoated thermopile, across the IR spectrum (3 μm–15.5 μm). This led to a four-fold amplification of the detected infrared signal (4.26 μm) in a CO{sub 2} non-dispersive-IR gas sensor system. The presence of the CNT layer was shown not to degrade the robustness of the uncoated devices, whilst the 50% modulation depth of the detector was only marginally reduced by 1.5 Hz. Moreover, we find that the 50% normalized absorption angular profile is subsequently more collimated by 8°. Our results demonstrate the viability of a CNT-based SOI CMOS IR sensor for low cost air quality monitoring.« less

Mask-less deposition of Au-SnO2 nanocomposites on CMOS MEMS platform for ethanol detection.

PubMed

Santra, S; Sinha, A K; De Luca, A; Ali, S Z; Udrea, F; Guha, P K; Ray, S K; Gardner, J W

2016-03-29

Here we report on the mask-less deposition of Au-SnO2 nanocomposites with a silicon-on-insulator (SOI) complementary metal oxide semiconductor (CMOS) micro electro mechanical system (MEMS) platform through the use of dip pen nanolithography (DPN) to create a low-cost ethanol sensor. MEMS technology is used in order to achieve low power consumption, by the employment of a membrane structure formed using deep reactive ion etching technique. The device consists of an embedded tungsten micro-heater with gold interdigitated electrodes on top of the SOI membrane. The tungsten micro-heater is used to raise the membrane temperature up to its operating temperature and the electrodes are used to measure the resistance of the nanocomposite sensing layer. The CMOS MEMS devices have high electro-thermal efficiency, with 8.2 °C temperature increase per mW power of consumption. The sensing material (Au-SnO2 nanocomposite) was synthesised starting from SnO nanoplates, then Au nanoparticles were attached chemically to the surface of SnO nanoplates, finally the mixture was heated at 700 °C in an oven in air for 4 h. This composite material was sonicated for 2 h in terpineol to make a viscous homogeneous slurry and then 'written' directly across the electrode area using the DPN technique without any mask. The devices were characterised by exposure to ethanol vapour in humid air in the concentration range of 100-1000 ppm. The sensitivity varied from 1.2 to 0.27 ppm(-1) for 100-1000 ppm of ethanol at 10% relative humid air. Selectivity measurements showed that the sensors were selective towards ethanol when they were exposed to acetone and toluene.

Mask-less deposition of Au-SnO2 nanocomposites on CMOS MEMS platform for ethanol detection

NASA Astrophysics Data System (ADS)

Santra, S.; Sinha, A. K.; De Luca, A.; Ali, S. Z.; Udrea, F.; Guha, P. K.; Ray, S. K.; Gardner, J. W.

2016-03-01

Here we report on the mask-less deposition of Au-SnO2 nanocomposites with a silicon-on-insulator (SOI) complementary metal oxide semiconductor (CMOS) micro electro mechanical system (MEMS) platform through the use of dip pen nanolithography (DPN) to create a low-cost ethanol sensor. MEMS technology is used in order to achieve low power consumption, by the employment of a membrane structure formed using deep reactive ion etching technique. The device consists of an embedded tungsten micro-heater with gold interdigitated electrodes on top of the SOI membrane. The tungsten micro-heater is used to raise the membrane temperature up to its operating temperature and the electrodes are used to measure the resistance of the nanocomposite sensing layer. The CMOS MEMS devices have high electro-thermal efficiency, with 8.2 °C temperature increase per mW power of consumption. The sensing material (Au-SnO2 nanocomposite) was synthesised starting from SnO nanoplates, then Au nanoparticles were attached chemically to the surface of SnO nanoplates, finally the mixture was heated at 700 °C in an oven in air for 4 h. This composite material was sonicated for 2 h in terpineol to make a viscous homogeneous slurry and then ‘written’ directly across the electrode area using the DPN technique without any mask. The devices were characterised by exposure to ethanol vapour in humid air in the concentration range of 100-1000 ppm. The sensitivity varied from 1.2 to 0.27 ppm-1 for 100-1000 ppm of ethanol at 10% relative humid air. Selectivity measurements showed that the sensors were selective towards ethanol when they were exposed to acetone and toluene.

An Analytical Approach for Relating Boiling Points of Monofunctional Organic Compounds to Intermolecular Forces

ERIC Educational Resources Information Center

Struyf, Jef

2011-01-01

The boiling point of a monofunctional organic compound is expressed as the sum of two parts: a contribution to the boiling point due to the R group and a contribution due to the functional group. The boiling point in absolute temperature of the corresponding RH hydrocarbon is chosen for the contribution to the boiling point of the R group and is a…

Correlational approach to turbulent saturated film boiling

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

Chu, T.Y.

A correlation method for saturated film boiling is proposed. The correlation is based on the analogy between film boiling and natural convection. As in the case of natural convection, the turbulent film boiling correlation takes the form of a Nusselt number versus the Raleigh number power law, Nu[sub B] [proportional to] Ra[sub B][sup 1.3]. The proposed correlation shows very good agreement with current data for film boiling of water from vertical surfaces. The general applicability of the correlation is established by comparisons with film boiling data from R-113 and cryogenic fluids. 25 refs., 8 figs.

The myth of the boiling point.

PubMed

Chang, Hasok

2008-01-01

Around 1800, many reputable scientists reported significant variations in the temperature of pure water boiling under normal atmospheric pressure. The reported variations included a difference of over 1 degree C between boiling in metallic and glass vessels (Gay-Lussac), and "superheating" up to 112 degrees C on extracting dissolved air out of water (De Luc). I have confirmed most of these observations in my own experiments, many of which are described in this paper. Water boils at the "boiling point" only under very particular circumstances. Our common-sense intuition about the fixedness of the boiling point is only sustained by our limited experience.

Size-exclusion chromatography for the determination of the boiling point distribution of high-boiling petroleum fractions.

PubMed

Boczkaj, Grzegorz; Przyjazny, Andrzej; Kamiński, Marian

2015-03-01

The paper describes a new procedure for the determination of boiling point distribution of high-boiling petroleum fractions using size-exclusion chromatography with refractive index detection. Thus far, the determination of boiling range distribution by chromatography has been accomplished using simulated distillation with gas chromatography with flame ionization detection. This study revealed that in spite of substantial differences in the separation mechanism and the detection mode, the size-exclusion chromatography technique yields similar results for the determination of boiling point distribution compared with simulated distillation and novel empty column gas chromatography. The developed procedure using size-exclusion chromatography has a substantial applicability, especially for the determination of exact final boiling point values for high-boiling mixtures, for which a standard high-temperature simulated distillation would have to be used. In this case, the precision of final boiling point determination is low due to the high final temperatures of the gas chromatograph oven and an insufficient thermal stability of both the gas chromatography stationary phase and the sample. Additionally, the use of high-performance liquid chromatography detectors more sensitive than refractive index detection allows a lower detection limit for high-molar-mass aromatic compounds, and thus increases the sensitivity of final boiling point determination. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Effect of soaking, boiling, and steaming on total phenolic contentand antioxidant activities of cool season food legumes.

PubMed

Xu, Baojun; Chang, Sam K C

2008-09-01

The effects of soaking, boiling and steaming processes on the total phenolic components and antioxidant activity in commonly consumed cool season food legumes (CSFL's), including green pea, yellow pea, chickpea and lentil were investigated. As compared to original unprocessed legumes, all processing steps caused significant (p<0.05) decreases in total phenolic content (TPC), DPPH free radical scavenging activity (DPPH) in all tested CSFL's. All soaking and atmospheric boiling treatments caused significant (p<0.05) decreases in oxygen radical absorbing capacity (ORAC). However, pressure boiling and pressure steaming caused significant (p<0.05) increases in ORAC values. Steaming treatments resulted in a greater retention of TPC, DPPH, and ORAC values in all tested CSFL's as compared to boiling treatments. To obtain cooked legumes with similar palatability and firmness, pressure boiling shortened processing time as compared to atmospheric boiling, resulted in insignificant differences in TPC, DPPH for green and yellow pea. However, TPC and DPPH in cooked lentils differed significantly between atmospheric and pressure boiling. As compared to atmospheric processes, pressure processes significantly increased ORAC values in both boiled and steamed CSFL's. Greater TPC, DPPH and ORAC values were detected in boiling water than that in soaking and steaming water. Boiling also caused more solid loss than steaming. Steam processing exhibited several advantages in retaining the integrity of the legume appearance and texture of the cooked product, shortening process time, and greater retention of antioxidant components and activities. Copyright © 2008 Elsevier Ltd. All rights reserved.

Fluid inclusion from drill hole DW-5, Hohi geothermal area, Japan: Evidence of boiling and procedure for estimating CO2 content

USGS Publications Warehouse

Sasada, M.; Roedder, E.; Belkin, H.E.

1986-01-01

Fluid inclusion studies have been used to derive a model for fluid evolution in the Hohi geothermal area, Japan. Six types of fluid inclusions are found in quartz obtained from the drill core of DW-5 hole. They are: (I) primary liquid-rich with evidence of boiling; (II) primary liquid-rich without evidence of boiling; (III) primary vapor-rich (assumed to have been formed by boiling); (IV) secondary liquid-rich with evidence of boiling; (V) secondary liquid-rich without evidence of boiling; (VI) secondary vapor-rich (assumed to have been formed by boiling). Homogenization temperatures (Th) range between 196 and 347??C and the final melting point of ice (Tm) between -0.2 and -4.3??C. The CO2 content was estimated semiquantitatively to be between 0 and 0.39 wt. % based on the bubble behavior on crushing. NaCl equivalent solid solute salinity of fluid inclusions was determined as being between 0 and 6.8 wt. % after minor correction for CO2 content. Fluid inclusions in quartz provide a record of geothermal activity of early boiling and later cooling. The CO2 contents and homogenization temperatures of fluid inclusions with evidence of boiling generally increase with depth; these changes, and NaCl equivalent solid solute salinity of the fluid can be explained by an adiabatic boiling model for a CO2-bearing low-salinity fluid. Some high-salinity inclusions without CO2 are presumed to have formed by a local boiling process due to a temperature increase or a pressure decrease. The liquid-rich primary and secondary inclusions without evidence of boiling formed during the cooling process. The salinity and CO2 content of these inclusions are lower than those in the boiling fluid at the early stage, probably as a result of admixture with groundwater. ?? 1986.

Transition boiling heat transfer and the film transition regime

NASA Technical Reports Server (NTRS)

Ramilison, J. M.; Lienhard, J. H.

1987-01-01

The Berenson (1960) flat-plate transition-boiling experiment has been recreated with a reduced thermal resistance in the heater, and an improved access to those portions of the transition boiling regime that have a steep negative slope. Tests have been made in Freon-113, acetone, benzene, and n-pentane boiling on horizontal flat copper heaters that have been mirror-polished, 'roughened', or teflon-coated. The resulting data reproduce and clarify certain features observed by Berenson: the modest surface finish dependence of boiling burnout, and the influence of surface chemistry on both the minimum heat flux and the mode of transition boiling, for example. A rational scheme of correlation yields a prediction of the heat flux in what Witte and Lienhard (1982) previously identified as the 'film-transition boiling' region. It is also shown how to calculate the heat flux at the boundary between the pure-film, and the film-transition, boiling regimes, as a function of the advancing contact angle.

Feasibility study of a brine boiling machine by solar energy

NASA Astrophysics Data System (ADS)

Phayom, W.

2018-06-01

This study presented the technical and operational feasibility of brine boiling machine by using solar energy instead of firewood or husk for salt production. The solar salt brine boiling machine consisted of a boiling chamber with an enhanced thermal efficiency through use of a solar brine heater. The stainless steel solar salt brine boiling chamber had dimensions of 60 cm x 70 cm x 20 cm. The steel brine heater had dimensions of 70 cm x 80 cm x 20 cm. The tilt angle of both the boiling chamber and brine heater was 20 degrees from horizontal. The brine temperature in the reservoir tank was 42°C with a flow rate of 6.64 L/h discharging into the solar boiling machine. It was found that the thermal efficiency and overall efficiency of the solar salt brine boiling machine were 0.63 and 0.38, respectively at a solar irradiance of 787.6 W/m2. The results shows that the potential of using solar energy for salt production system is feasible.

Nucleate pool boiling in subcooled liquid under microgravity: Results of TEXUS experimental investigations

NASA Astrophysics Data System (ADS)

Zell, M.; Straub, J.; Weinzierl, A.

1984-12-01

Experiments on subcooled nucleate pool boiling in microgravity were carried out to separate gravity driven effects on heat transfer within the boiling process. A ballistic trajectory by sounding rocket flight (TEXUS 5 and 10) achieved a gravity level of a/g = 0.0001 for 360 sec. For determination of geometrical effects on heat transport two different experimental configurations (platinum wire and flat plate) were employed. Boiling curves and bubble dynamics recorded by cinematography lead to gravity independent modelling of the boiling phenomena. The results ensure the applicability and high efficiency of nucleate pool boiling for heat exchangers in space laboratories.

Household Water Disinfection in Hurricane-Affected Communities of Louisiana: Implications for Disaster Preparedness for the General Public

PubMed Central

Ram, Pavani K.; Blanton, Elizabeth; Klinghoffer, Debra; Platek, Mary; Piper, Janet; Straif-Bourgeois, Susanne; Bonner, Matthew R.; Mintz, Eric D.

2007-01-01

Objectives. Thousands of Louisiana residents were asked to boil water because of widespread disruptions in electricity and natural gas services after Hurricane Rita. We sought to assess awareness of boil water orders and familiarity with household water disinfection techniques other than boiling. Methods. We conducted a cross-sectional survey in randomly selected mobile home communities in Louisiana. Results. We interviewed 196 respondents from 8 communities, which had boil water orders instituted. Of 97 who were home while communities were still under orders to boil water, 30 (31%) were aware of the orders and, of those, 24 (80%) said the orders were active while they were living at home; of the 24, 10 (42%) reported boiling water. Overall, 163 (83%) respondents were aware of a method of water disinfection at the household level: boiling (78%), chlorination (27%), and filtration (25%); 87% had a container of chlorine bleach at home. Conclusions. Few hurricane-affected respondents were aware of boil water orders and of alternate water disinfection techniques. Most had access to chlorine and could have practiced household chlorination if disruption in natural gas and electricity made boiling impossible. PMID:17413065

Acoustic emission feedback control for control of boiling in a microwave oven

DOEpatents

White, Terry L.

1991-01-01

An acoustic emission based feedback system for controlling the boiling level of a liquid medium in a microwave oven is provided. The acoustic emissions from the medium correlated with surface boiling is used to generate a feedback control signal proportional to the level of boiling of the medium. This signal is applied to a power controller to automatically and continuoulsly vary the power applied to the oven to control the boiling at a selected level.

Water boiling inside carbon nanotubes: toward efficient drug release.

PubMed

Chaban, Vitaly V; Prezhdo, Oleg V

2011-07-26

We show using molecular dynamics simulation that spatial confinement of water inside carbon nanotubes (CNTs) substantially increases its boiling temperature and that a small temperature growth above the boiling point dramatically raises the inside pressure. Capillary theory successfully predicts the boiling point elevation down to 2 nm, below which large deviations between the theory and atomistic simulation take place. Water behaves qualitatively different inside narrow CNTs, exhibiting transition into an unusual phase, where pressure is gas-like and grows linearly with temperature, while the diffusion constant is temperature-independent. Precise control over boiling by CNT diameter, together with the rapid growth of inside pressure above the boiling point, suggests a novel drug delivery protocol. Polar drug molecules are packaged inside CNTs; the latter are delivered into living tissues and heated by laser. Solvent boiling facilitates drug release.

Performance of a 12-coil superconducting bumpy torus magnet facility

NASA Technical Reports Server (NTRS)

Roth, J. R.; Holmes, A. D.; Keller, T. A.; Krawczonek, W. M.

1972-01-01

The bumpy torus facility consists of 12 superconducting coils, each 19 cm i.d. and capable of 3.0 teslas on their axes. The coils are equally spaced around a toroidal array with a major diameter of 1.52 m, and are mounted with the major axis of the torus vertical in a single vacuum tank 2.6 m in diameter. Final shakedown tests of the facility mapped out its magnetic, cryogenic, vacuum, mechanical, and electrical performance. The facility is now ready for use as a plasma physics research facility. A maximum magnetic field on the magnetic axis of 3.23 teslas was held for a period of more than sixty minutes without a coil normalcy. The design field was 3.00 teslas. The steady-state liquid helium boil-off rate was 87 liters per hour of liquid helium without the coils charged. The coil array was stable when subjected to an impulsive loading, even with the magnets fully charged. When the coils were charged to a maximum magnetic field of 3.35 teslas, the system was driven normal without damage.

Large-scale testing of in-vessel debris cooling through external flooding of the reactor pressure vessel in the CYBL facility

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

Chu, T.Y.; Bentz, J.H.; Bergeron, K.D.

1994-04-01

The possibility of achieving in-vessel core retention by flooding the reactor cavity, or the ``flooded cavity``, is an accident management concept currently under consideration for advanced light water reactors (ALWR), as well as for existing light water reactors (LWR). The CYBL (CYlindrical BoiLing) facility is a facility specifically designed to perform large-scale confirmatory testing of the flooded cavity concept. CYBL has a tank-within-a-tank design; the inner 3.7 m diameter tank simulates the reactor vessel, and the outer tank simulates the reactor cavity. The energy deposition on the bottom head is simulated with an array of radiant heaters. The array canmore » deliver a tailored heat flux distribution corresponding to that resulting from core melt convection. The present paper provides a detailed description of the capabilities of the facility, as well as results of recent experiments with heat flux in the range of interest to those required for in-vessel retention in typical ALWRs. The paper concludes with a discussion of other experiments for the flooded cavity applications.« less

When water does not boil at the boiling point.

PubMed

Chang, Hasok

2007-03-01

Every schoolchild learns that, under standard pressure, pure water always boils at 100 degrees C. Except that it does not. By the late 18th century, pioneering scientists had already discovered great variations in the boiling temperature of water under fixed pressure. So, why have most of us been taught that the boiling point of water is constant? And, if it is not constant, how can it be used as a 'fixed point' for the calibration of thermometers? History of science has the answers.

Nucleate Pool Boiling Performance of Smooth and Finned Tube Bundles in R-113 and R-114/Oil Mixtures

DTIC Science & Technology

1989-06-01

tfilm Film thermodynamic temperature (K) Tfilm Film Celcius temperature (C) Tldl Liquid temperature (C) Tld2 Liquid temperature (C) Tn Tube wall local...surface immersed in a pool of saturated liquid is the most thoroughly studied boiling heat-transfer mechanism, when compared to partial film boiling and... film boiling. Figure 2.1 shows the characteristic boiling curve of a heated surface immersed in a froon. As the surface is heated up, heat is

Boiling incipience and convective boiling of neon and nitrogen

NASA Technical Reports Server (NTRS)

Papell, S. S.; Hendricks, R. C.

1977-01-01

Forced convection and subcooled boiling heat transfer data for liquid nitrogen and liquid neon were obtained in support of a design study for a 30 tesla cryomagnet cooled by forced convection of liquid neon. The cryogen data obtained over a range of system pressures, fluid flow rates, and applied heat fluxes were used to develop correlations for predicting boiling incipience and convective boiling heat transfer coefficients in uniformly heated flow channels. The accuracy of the correlating equations was then evaluated. A technique was also developed to calculate the position of boiling incipience in a uniformly heated flow channel. Comparisons made with the experimental data showed a prediction accuracy of + or - 15 percent.

A numerical investigation of the effect of surface wettability on the boiling curve.

PubMed

Hsu, Hua-Yi; Lin, Ming-Chieh; Popovic, Bridget; Lin, Chii-Ruey; Patankar, Neelesh A

2017-01-01

Surface wettability is recognized as playing an important role in pool boiling and the corresponding heat transfer curve. In this work, a systematic study of pool boiling heat transfer on smooth surfaces of varying wettability (contact angle range of 5° - 180°) has been conducted and reported. Based on numerical simulations, boiling curves are calculated and boiling dynamics in each regime are studied using a volume-of-fluid method with contact angle model. The calculated trends in critical heat flux and Leidenfrost point as functions of surface wettability are obtained and compared with prior experimental and theoretical predictions, giving good agreement. For the first time, the effect of contact angle on the complete boiling curve is shown. It is demonstrated that the simulation methodology can be used for studying pool boiling and related dynamics and providing more physical insights.

A numerical investigation of the effect of surface wettability on the boiling curve

PubMed Central

Lin, Ming-Chieh; Popovic, Bridget; Lin, Chii-Ruey; Patankar, Neelesh A.

2017-01-01

Surface wettability is recognized as playing an important role in pool boiling and the corresponding heat transfer curve. In this work, a systematic study of pool boiling heat transfer on smooth surfaces of varying wettability (contact angle range of 5° − 180°) has been conducted and reported. Based on numerical simulations, boiling curves are calculated and boiling dynamics in each regime are studied using a volume-of-fluid method with contact angle model. The calculated trends in critical heat flux and Leidenfrost point as functions of surface wettability are obtained and compared with prior experimental and theoretical predictions, giving good agreement. For the first time, the effect of contact angle on the complete boiling curve is shown. It is demonstrated that the simulation methodology can be used for studying pool boiling and related dynamics and providing more physical insights. PMID:29125847

A Novel Role of Three Dimensional Graphene Foam to Prevent Heater Failure during Boiling

PubMed Central

Ahn, Ho Seon; Kim, Ji Min; Park, Chibeom; Jang, Ji-Wook; Lee, Jae Sung; Kim, Hyungdae; Kaviany, Massoud; Kim, Moo Hwan

2013-01-01

We report a novel boiling heat transfer (NBHT) in reduced graphene oxide (RGO) suspended in water (RGO colloid) near critical heat flux (CHF), which is traditionally the dangerous limitation of nucleate boiling heat transfer because of heater failure. When the heat flux reaches the maximum value (CHF) in RGO colloid pool boiling, the wall temperature increases gradually and slowly with an almost constant heat flux, contrary to the rapid wall temperature increase found during water pool boiling. The gained time by NBHT would provide the safer margin of the heat transfer and the amazing impact on the thermal system as the first report of graphene application. In addition, the CHF and boiling heat transfer performance also increase. This novel boiling phenomenon can effectively prevent heater failure because of the role played by the self-assembled three-dimensional foam-like graphene network (SFG). PMID:23743619

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.

Experimental investigation on the phenomena around the onset nucleate boiling during the impacting of a droplet on the hot surface

NASA Astrophysics Data System (ADS)

Mitrakusuma, Windy H.; Deendarlianto, Kamal, Samsul; Indarto, Nuriyadi, M.

2016-06-01

Onset of nucleate boiling of a droplet when impacted onto hot surface was investigated. Three kinds of surfaces, normal stainless steel (NSS), stainless steel with TiO2 coating (UVN), and stainless steel with TiO2 coating and radiated by ultraviolet ray were employed to examine the effect of wettability. The droplet size was 2.4 mm diameter, and dropped under different We number. The image is generated by high speed camera with the frame speed of 1000 fps. The boiling conditions are identified as natural convection, nucleate boiling, critical heat flux, transition, and film boiling. In the present report, the discussion will be focused on the beginning of nucleate boiling on the droplet. Nucleate boiling occurs when bubbles are generated. These bubbles are probably caused by nucleation on the impurities within the liquid rather than at nucleation sites on the heated surface because the bubbles appear to be in the bulk of the liquid instead of at the liquid-solid interface. In addition, the smaller the contact angle, the fastest the boiling.

Alkali metal pool boiler life tests for a 25 kWe advanced Stirling conversion system

NASA Technical Reports Server (NTRS)

Anderson, W. G.; Rosenfeld, J. H.; Noble, J.

1991-01-01

The overall operating temperature and efficiency of solar-powered Stirling engines can be improved by adding an alkali metal pool boiler heat transport system to supply heat more uniformly to the heater head tubes. One issue with liquid metal pool boilers is unstable boiling. Stable boiling is obtained with an enhanced boiling surface containing nucleation sites that promote continuous boiling. Over longer time periods, it is possible that the boiling behavior of the system will change. An 800-h life test was conducted to verify that pool boiling with the chosen fluid/surface combination remains stable as the system ages. The apparatus uses NaK boiling on a - 100 + 140 stainless steel sintered porous layer, with the addition of a small amount of xenon. Pool boiling remained stable to the end of life test. The pool boiler life test included a total of 82 cold starts, to simulate startup each morning, and 60 warm restarts, to simulate cloud cover transients. The behavior of the cold and warm starts showed no significant changes during the life test. In the experiments, the fluid/surface combination provided stable, high-performance boiling at the operating temperature of 700 C. Based on these experiments, a pool boiler was designed for a full-scale 25-kWe Stirling system.

Evaluation of fresh pasta-making properties of extra-strong common wheat (Triticum aestivum L.).

PubMed

Ito, Miwako; Maruyama-Funatsuki, Wakako; Ikeda, Tatsuya M; Nishio, Zenta; Nagasawa, Koichi; Tabiki, Tadashi; Yamauchi, Hiroaki

2012-12-01

The relationship between characterictics of flour of common wheat varieties and fresh pasta-making qualitites was examined, and the fresh pasta-making properties of extra-strong varieties that have extra-strong dough were evaluated. There was a positive correlation between mixing time (PT) and hardness of boiled pasta, indicating that the hardness of boiled pasta was affected by dough properties. Boiled pasta made from extra-strong varieties, Yumechikara, Hokkai 262 and Hokkai 259, was harder than that from other varieties and commercial flour. There was a negative correlation between flour protein content and brightness of boiled pasta. The colors of boiled pasta made from Yumechikara and Hokkai 262 grown under the condition of standard manuring culture were superior to those of boiled pasta made from other varieties. Discoloration of boiled pasta made from Yumechikara grown under the condition of heavy manuring culture was caused by increase of flour protein content. On the other hand, discoloration of boiled pasta made from Hokkai 262 grown under the condition of heavy manuring culture was less than that of boiled pasta made from Yumechikara. These results indicate that pasta made from extra-strong wheat varieties has good hardness and that Hokkai 262 has extraordinary fresh pasta-making properties.

Evaluation of fresh pasta-making properties of extra-strong common wheat (Triticum aestivum L.)

PubMed Central

Ito, Miwako; Maruyama-Funatsuki, Wakako; Ikeda, Tatsuya M.; Nishio, Zenta; Nagasawa, Koichi; Tabiki, Tadashi; Yamauchi, Hiroaki

2012-01-01

The relationship between characterictics of flour of common wheat varieties and fresh pasta-making qualitites was examined, and the fresh pasta-making properties of extra-strong varieties that have extra-strong dough were evaluated. There was a positive correlation between mixing time (PT) and hardness of boiled pasta, indicating that the hardness of boiled pasta was affected by dough properties. Boiled pasta made from extra-strong varieties, Yumechikara, Hokkai 262 and Hokkai 259, was harder than that from other varieties and commercial flour. There was a negative correlation between flour protein content and brightness of boiled pasta. The colors of boiled pasta made from Yumechikara and Hokkai 262 grown under the condition of standard manuring culture were superior to those of boiled pasta made from other varieties. Discoloration of boiled pasta made from Yumechikara grown under the condition of heavy manuring culture was caused by increase of flour protein content. On the other hand, discoloration of boiled pasta made from Hokkai 262 grown under the condition of heavy manuring culture was less than that of boiled pasta made from Yumechikara. These results indicate that pasta made from extra-strong wheat varieties has good hardness and that Hokkai 262 has extraordinary fresh pasta-making properties. PMID:23341748

Enabling Highly Effective Boiling from Superhydrophobic Surfaces

NASA Astrophysics Data System (ADS)

Allred, Taylor P.; Weibel, Justin A.; Garimella, Suresh V.

2018-04-01

A variety of industrial applications such as power generation, water distillation, and high-density cooling rely on heat transfer processes involving boiling. Enhancements to the boiling process can improve the energy efficiency and performance across multiple industries. Highly wetting textured surfaces have shown promise in boiling applications since capillary wicking increases the maximum heat flux that can be dissipated. Conversely, highly nonwetting textured (superhydrophobic) surfaces have been largely dismissed for these applications as they have been shown to promote formation of an insulating vapor film that greatly diminishes heat transfer efficiency. The current Letter shows that boiling from a superhydrophobic surface in an initial Wenzel state, in which the surface texture is infiltrated with liquid, results in remarkably low surface superheat with nucleate boiling sustained up to a critical heat flux typical of hydrophilic wetting surfaces, and thus upends this conventional wisdom. Two distinct boiling behaviors are demonstrated on both micro- and nanostructured superhydrophobic surfaces based on the initial wetting state. For an initial surface condition in which vapor occupies the interstices of the surface texture (Cassie-Baxter state), premature film boiling occurs, as has been commonly observed in the literature. However, if the surface texture is infiltrated with liquid (Wenzel state) prior to boiling, drastically improved thermal performance is observed; in this wetting state, the three-phase contact line is pinned during vapor bubble growth, which prevents the development of a vapor film over the surface and maintains efficient nucleate boiling behavior.

Development of Flow Boiling and Condensation Experiment on the International Space Station- Normal and Low Gravity Flow Boiling Experiment Development and Test Results

NASA Technical Reports Server (NTRS)

Nahra, Henry K.; Hall, Nancy R.; Hasan, Mohammad M.; Wagner, James D.; May, Rochelle L.; Mackey, Jeffrey R.; Kolacz, John S.; Butcher, Robert L.; Frankenfield, Bruce J.; Mudawar, Issam;

Pool and flow boiling in variable and microgravity

NASA Technical Reports Server (NTRS)

Merte, Herman, Jr.

1994-01-01

As is well known, boiling is an effective mode of heat transfer in that high heat flux levels are possible with relatively small temperature differences. Its optimal application requires that the process be adequately understood. A measure of the understanding of any physical event lies in the ability to predict its behavior in terms of the relevant parameters. Despite many years of research the predictability of boiling is currently possible only for quite specialized circumstances, e.g., the critical heat flux and film boiling for the pool boiling case, and then only with special geometries. Variable gravity down to microgravity provides the opportunity to test this understanding, but possibly more important, by changing the dimensional and time scales involved permits more detailed observations of elements involved in the boiling process, and perhaps discloses phenomena heretofore unknown. The focus here is on nucleate boiling although, as will be demonstrated below, under but certain circumstances in microgravity it can take place concurrently with the dryout process. In the presence of earth gravity or forced convection effects, the latter process is usually referred to as film boiling. However, no vapor film as such forms with pool boiling in microgravity, only dryout. Initial results are presented here for pool boiling in microgravity, and were made possible at such an early date by the availability of the Get-Away-Specials (GAS). Also presented here are some results of ground testing of a flow loop for the study of low velocity boiling, eventually to take place also in microgravity. In the interim, variable buoyancy normal to the heater surface is achieved by rotation of the entire loop relative to earth gravity. Of course, this is at the expense of varying the buoyancy parallel to the heater surface. Two questions which must be resolved early in the study of flow boiling in microgravity are (1) the lower limits of liquid flow velocity where buoyancy effects become significant to the boiling process (2) the effect of lower liquid flow velocities on the Critical Heat Flux when buoyancy is removed. Results of initial efforts in these directions are presented, albeit restricted currently to the ever present earth gravity.

Steady State Film Boiling Heat Transfer Simulated With Trace V4.160

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

Audrius Jasiulevicius; Rafael Macian-Juan

2006-07-01

This paper presents the results of the assessment and analysis of TRACE v4.160 heat transfer predictions in the post-CHF (critical heat flux) region and discusses the possibilities to improve the TRACE v4.160 code predictions in the film boiling heat transfer when applying different film boiling correlations. For this purpose, the TRACE v4.160-calculated film boiling heat flux and the resulting maximum inner wall temperatures during film boiling in single tubes were compared with experimental data obtained at the Royal Institute of Technology (KTH) in Stockholm, Sweden. The experimental database included measurements for pressures ranging from 30 to 200 bar and coolantmore » mass fluxes from 500 to 3000 kg/m{sup 2}s. It was found that TRACE v4.160 does not produce correct predictions of the film boiling heat flux, and consequently of the maximum inner wall temperature in the test section, under the wide range of conditions documented in the KTH experiments. In particular, it was found that the standard TRACE v4.160 under-predicts the film boiling heat transfer coefficient at low pressure-low mass flux and high pressure-high mass flux conditions. For most of the rest of the investigated range of parameters, TRACE v4.160 over-predicts the film boiling heat transfer coefficient, which can lead to non-conservative predictions in applications to nuclear power plant analyses. Since no satisfactory agreement with the experimental database was obtained with the standard TRACE v4.160 film boiling heat transfer correlations, we have added seven film boiling correlations to TRACE v4.160 in order to investigate the possibility to improve the code predictions for the conditions similar to the KTH tests. The film boiling correlations were selected among the most commonly used film boiling correlations found in the open literature, namely Groeneveld 5.7, Bishop (2 correlations), Tong, Konkov, Miropolskii and Groeneveld-Delorme correlations. The only correlation among the investigated, which resulted in a significant improvement of TRACE predictions, was the Groeneveld 5.7. It was found, that replacing the current film boiling correlation (Dougall-Rohsenow) for the wall-togas heat transfer with Groeneveld 5.7 improves the code predictions for the film boiling heat transfer at high qualities in single tubes in the entire range of pressure and coolant mass flux considered. (authors)« less

Fabrication of Monolithic Sapphire Membranes for High T(sub c) Bolometer Array Development

NASA Technical Reports Server (NTRS)

Pugel, D. E.; Lakew, B.; Aslam, S.; Wang, L.

2004-01-01

This paper examines the effectiveness of Pt/Cr thin film masks for the architecture of monolithic membrane structures in r-plane single crystal sapphire. The development of a pinhole-free Pt/Cr composite mask that is resistant to boiling H2SO4:H3PO4 etchant will lead to the fabrication of smooth sapphire membranes whose surfaces are well-suited for the growth of low-noise high Tc films. In particular, the relationship of thermal annealing conditions on the Pt/Cr composite mask system to: (1) changes in the surface morphology (2) elemental concentration of the Pt/Cr thin film layers and (3) etch pit formation on the sapphire surface will be presented.

SEISMIC STUDY OF THE AGUA DE PAU GEOTHERMAL PROSPECT, SAO MIGUEL, AZORES.

USGS Publications Warehouse

Dawson, Phillip B.; Rodrigues da Silva, Antonio; Iyer, H.M.; Evans, John R.

1985-01-01

A 16 station array was operated over the 200 km**2 central portion of Sao Miguel utilizing 8 permanent Instituto Nacional de Meterologia e Geofisica stations and 8 USGS portable stations. Forty four local events with well constrained solutions and 15 regional events were located. In addition, hundreds of unlocatable seismic events were recorded. The most interesting seismic activity occurred in a swarm on September 6 and 7, 1983 when over 200 events were recorded in a 16 hour period. The seismic activity around Agua de Pau was centered on the east and northeast slopes of the volcano. The data suggest a boiling hydrothermal system beneath the Agua de Pau volcano, consistent with a variety of other data.

Experimental evidence of the vapor recoil mechanism in the boiling crisis.

PubMed

Nikolayev, V S; Chatain, D; Garrabos, Y; Beysens, D

2006-11-03

Boiling crisis experiments are carried out in the vicinity of the liquid-gas critical point of H2. A magnetic gravity compensation setup is used to enable nucleate boiling at near critical pressure. The measurements of the critical heat flux that defines the threshold for the boiling crisis are carried out as a function of the distance from the critical point. The obtained power law behavior and the boiling crisis dynamics agree with the predictions of the vapor recoil mechanism and disagree with the classical vapor column mechanism.

Conversion of direct process high-boiling residue to monosilanes

DOEpatents

Brinson, Jonathan Ashley; Crum, Bruce Robert; Jarvis, Jr., Robert Frank

2000-01-01

A process for the production of monosilanes from the high-boiling residue resulting from the reaction of hydrogen chloride with silicon metalloid in a process typically referred to as the "direct process." The process comprises contacting a high-boiling residue resulting from the reaction of hydrogen chloride and silicon metalloid, with hydrogen gas in the presence of a catalytic amount of aluminum trichloride effective in promoting conversion of the high-boiling residue to monosilanes. The present process results in conversion of the high-boiling residue to monosilanes. At least a portion of the aluminum trichloride catalyst required for conduct of the process may be formed in situ during conduct of the direct process and isolation of the high-boiling residue.

Characterizing preferential groundwater discharge through boils using temperature

NASA Astrophysics Data System (ADS)

Vandenbohede, A.; de Louw, P. G. B.; Doornenbal, P. J.

2014-03-01

In The Netherlands, preferential groundwater discharge trough boils is a key process in the salinization of deep polders. Previous work showed that boils also influence the temperature in the subsurface and of surface water. This paper elaborates on this process combining field observations with numerical modeling. As is the case for salinity, a distinct anomaly in the subsurface and surface water temperature can be attributed to boils. Lines of equal temperature are distorted towards the boil, which can be considered as an upconing of the temperature profile by analogy of the upconing of a fresh-saltwater interface. The zone of this distortion is limited to the immediate vicinity of the boil, being about 5 m in the aquitard which holds the boil's conduit, or maximum a few dozens of meters in the underlying aquifer. In the aquitard, heat transport is conduction dominated whereas this is convection dominated in the aquifer. The temperature anomaly differs from the salinity anomaly by the smaller radius of influence and faster time to reach a new steady-state of the former. Boils discharge water with a temperature equal to the mean groundwater temperature. This influences the yearly and diurnal variation of ditch water temperature in the immediate vicinity of the boil importantly but also the temperature in the downstream direction. Temporary nature of the boil (e.g. stability of the conduit, discharge rate), uncertainty on the 3D construction of the conduit and heterogeneity of the subsoil make it unlikely that temperature measurements can be interpreted further than a qualitative level.

A fundamental study of nucleate pool boiling under microgravity

NASA Technical Reports Server (NTRS)

Ervin, Jamie S.; Merte, Herman, Jr.

1991-01-01

An experimental study of incipient boiling in short-term microgravity and with a/g = +/- 1 for pool boiling was performed. Calibrated thin gold films sputtered on a smoothly polished quartz surface were used simultaneously for thermal resistance measurements and heating of the boiling surface. The gold films were used for both transient and quasi-steady heating surface temperature measurements. Two test vessels were constructed for precise measurement and control of fluid temperature and pressure: a laboratory pool boiling vessel for the a/g = +/- experiments and a pool boiling vessel designed for the 131 m free-fall in the NASA Lewis Research Center Microgravity Research Facility for the microgravity tests. Measurements included the heater surface temperature, the pressure near the heating surface, and the bulk liquid temperatures. High speed photography was used in the experiments. With high quality microgravity and the measured initial temperature of the quiescent test fluid, R113, the temperature distribution in the liquid at the moment of boiling inception resulting from an imposed step in heat flux is known with a certainty not possible previously. The types of boiling propagation across the large flat heating surface are categorized; the conditions necessary for their occurrence are described. Explosive boiling propagation with a striking pattern of small scale protuberances over the entire vapor mass periphery not observed previously at low heat flux levels is described. For the heater surface with a/g = -1, a step in the heater surface temperature of short duration was imposed. The resulting liquid temperature distribution at the moment of boiling inception was different from that obtained with a step in heat flux.

Nucleate pool boiling in the long duration low gravity environment of the space shuttle

NASA Technical Reports Server (NTRS)

Hasan, M. M.; Lin, C. S.; Knoll, R. H.; Bentz, M. D.; Meserole, J. S.

1993-01-01

The results are presented of an experimental study of nucleate pool boiling performed in the low gravity environment of the space shuttle. Photographic observations of pool boiling in Freon 113 were obtained during the 'Tank Pressure Control Experiment', flown on the Space Transportation System STS-43 in August 1991. Nucleate boiling data from large (relative to bubble size) flat heating surfaces (0.1046 by 0.0742 m) was obtained at very low heat fluxes (0.22 to 1.19 kw/so m). The system pressure and the bulk liquid subcooling varied in the range of 40 to 60 kPa and 3 to 5 C respectively. Thirty-eight boiling tests, each of 10 min duration for a given heat flux, were conducted. Measurements included the heater power, heater surface temperature, the liquid temperature and the system pressure as functions of heating time. Video data of the first 2 min of heating was recorded for each test. In some tests the video clearly shows the inception of boiling and the growth and departure of bubbles from the surface during the first 2 min of heating. In the absence of video data, the heater temperature variation during heating shows the inception of boiling and stable nucleate boiling. During the stable nucleate boiling, the wall superheat varied between 2.8 to 3.8 C for heat fluxes in the range of 0.95 to 1.19 kw/so m. The wall superheat at the inception of boiling varied between 2 to 13 C.

Nucleate pool boiling in the long duration low gravity environment of the Space Shuttle

NASA Technical Reports Server (NTRS)

Hasan, M. M.; Lin, C. S.; Knoll, R. H.; Bentz, M. D.; Meserole, J. S.

1993-01-01

The results are presented of an experimental study of nucleate pool boiling performed in the low gravity environment of the space shuttle. Photographic observations of pool boiling in Freon 113 were obtained during the 'Tank Pressure Control Experiment,' flown on the Space Transportation System, STS-43 in August 1991. Nucleate boiling data from large (relative to bubble size) flat heating surfaces (0.1046 by 0.0742 m) was obtained at very low heat fluxes (0.22 to 1.19 kW/sq m). The system pressure and the bulk liquid subcooling varied in the range of 40 to 60 kPa and 3 to 5 C respectively. Thirty-eight boiling tests, each of 10-min duration for a given heat flux, were conducted. Measurements included the heater power, heater surface temperature, the liquid temperature and the system pressure as functions of heating time. Video data of the first 2 min of heating was recorded for each test. In some tests the video clearly shows the inception of boiling and the growth and departure of bubbles from the surface during the first 2 min of heating. In the absence of video data, the heater temperature variation during heating shows the inception of boiling and stable nucleate boiling. During the stable nucleate boiling, the wall superheat varied between 2.8 to 3.8 C for heat fluxes in the range of 0.95 to 1.19 kW/sq m. The wall superheat at the inception of boiling varied between 2 to 13 C.

Determination of Sodium, Potassium, Magnesium, and Calcium Minerals Level in Fresh and Boiled Broccoli and Cauliflower by Atomic Absorption Spectrometry

NASA Astrophysics Data System (ADS)

Nerdy

2018-01-01

Vegetables from the cabbage family vegetables consumed by many people, which is known healthful, by eaten raw, boiled, or cooked (stir fry or soup). Vegetables like broccoli and cauliflower contain vitamins, minerals, and fiber. This study aims to determine the decrease percentage of sodium, potassium, magnesium, and calcium minerals level caused by boiled broccoli and cauliflower by atomic absorption spectrometry. Boiled broccoli and cauliflower prepared by given boiled treatment in boiling water for 3 minutes. Fresh and boiled broccoli and cauliflower carried out dry destruction, followed by quantitative analysis of sodium, potassium, magnesium, and calcium minerals respectively at a wavelength of 589.0 nm; 766.5 nm; 285.2 nm; and 422.7 nm, using atomic absorption spectrometry methods. After the determination of the sodium, potassium, magnesium, and calcium minerals level followed by validation of analytical methods with accuracy, precision, linearity, range, limit of detection (LOD), and limit of quantitation (LOQ) parameters. Research results show a decrease in the sodium, potassium, magnesium, and calcium minerals level in boiled broccoli and cauliflower compared with fresh broccoli and cauliflower. Validation of analytical methods gives results that spectrometry methods used for determining sodium, potassium, magnesium, and calcium minerals level are valid. It concluded that the boiled gives the effect of decreasing the minerals level significantly in broccoli and cauliflower.

Experimental investigation on the phenomena around the onset nucleate boiling during the impacting of a droplet on the hot surface

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

Mitrakusuma, Windy H., E-mail: windyhm@polban.ac.id; Refrigeration and Airconditioning Department, Politeknik Negeri Bandung, Jl. Gegerkalong Hilir, Ds. Ciwaruga Kotak Pos 1234 Bandung; Deendarlianto,

2016-06-03

Onset of nucleate boiling of a droplet when impacted onto hot surface was investigated. Three kinds of surfaces, normal stainless steel (NSS), stainless steel with TiO{sub 2} coating (UVN), and stainless steel with TiO{sub 2} coating and radiated by ultraviolet ray were employed to examine the effect of wettability. The droplet size was 2.4 mm diameter, and dropped under different We number. The image is generated by high speed camera with the frame speed of 1000 fps. The boiling conditions are identified as natural convection, nucleate boiling, critical heat flux, transition, and film boiling. In the present report, the discussionmore » will be focused on the beginning of nucleate boiling on the droplet. Nucleate boiling occurs when bubbles are generated. These bubbles are probably caused by nucleation on the impurities within the liquid rather than at nucleation sites on the heated surface because the bubbles appear to be in the bulk of the liquid instead of at the liquid-solid interface. In addition, the smaller the contact angle, the fastest the boiling.« less

On the pulse boiling frequency in thermosyphons

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

Liu, J.F.; Wang, J.C.Y.

1992-02-01

The unsteady periodic boiling phenomenon, pulse boiling, appearing in the evaporator of thermosyphons has been mentioned and investigated by many researchers. The heat transfer coefficient in evaporators was predicted according to different considerations of flow patterns. For instance, Shiraishi et al. proposed a method based on a combination flow pattern: the nucleate boiling in a liquid pool and the evaporation from a falling condensate film. Liu et al. only considered a pure pulse boiling flow pattern, and Xin et al. focused on the flow pattern of the continuous boiling process without pulse phenomenon. Besides, the forming conditions of pulse boilingmore » were also described differently. Xin et al. also reported that pulse boiling cannot occur in a carbon-steel/water heat pipe; Ma et al., however, observed this phenomenon in a carbon-steel/water thermosyphon. Nearly all researchers mentioned that this phenomenon indeed exists in glass/water thermosyphons. Although the influential factors have been discussed qualitatively, the quantitative analysis has yet to be conducted. This study focuses on the pulse boiling frequency as a criterion for the determination of flow patterns, and attempts are made to predict the frequency both experimentally and theoretically.« less

The use of preservatives consist of green tea, piper betel and potassium sorbate on boiled salted fish processing

NASA Astrophysics Data System (ADS)

Ariyani, F.; Hermana, I.; Hidayah, I.

2018-03-01

The main problem in boiled salted fish ikan pindang is mucus and mold on the surface of the fish which is produced relatively fast as well as the high level of histamine content especially when scombroid fish species are used as raw material. This study was performed to evaluate the effectiveness of various preservatives to overcome such problems. Three combinations of preservatives P1 (green tea and sorbate), P3 (green tea, piper betel, sorbate), P4 (green tea and piper betel) and P0 (no preservative/control) resulted from the previous study were used in this study. Before being used, the preservatives were tested against deteriorating microorganisms commonly found in boiled salted products, of which the result showed that all microorganisms were inhibited. The preservatives were then applied at three different stages of the process of boiled salted fish, i.e. before boiling, during boiling and after boiling. Sensory attributes and microbial characteristics of the products were then evaluated. The results showed that the performance of all tested preservatives against deteriorating microorganisms was relatively similar. It was also shown that the application before and during boiling performed better.

Cooling of hot bubbles by surface texture during the boiling crisis

NASA Astrophysics Data System (ADS)

Dhillon, Navdeep; Buongiorno, Jacopo; Varanasi, Kripa

2015-11-01

We report the existence of maxima in critical heat flux (CHF) enhancement for pool boiling on textured hydrophilic surfaces and reveal the interaction mechanism between bubbles and surface texture that governs the boiling crisis phenomenon. Boiling is a process of fundamental importance in many engineering and industrial applications but the maximum heat flux that can be absorbed by the boiling liquid (or CHF) is limited by the boiling crisis. Enhancing the CHF of industrial boilers by surface texturing can lead to substantial energy savings and reduction in greenhouse gas emissions on a global scale. However, the fundamental mechanisms behind this enhancement are not well understood, with some previous studies indicating that CHF should increase monotonically with increasing texture density. However, using pool boiling experiments on a parametrically designed set of plain and nano-textured micropillar surfaces, we show that there is an optimum intermediate texture density that maximizes CHF and further that the length scale of this texture is of fundamental significance. Using imbibition experiments and high-speed optical and infrared imaging, we reveal the fundamental mechanisms governing the CHF enhancement maxima in boiling crisis. We acknowledge funding from the Chevron corporation.

Transient boiling heat transfer in saturated liquid nitrogen and F113 at standard and zero gravity

NASA Technical Reports Server (NTRS)

Oker, E.; Merte, H., Jr.

1973-01-01

Transient and steady state nucleate boiling in saturated LN2 and F113 at standard and near zero gravity conditions were investigated for the horizontal up, vertical and horizontal down orientations of the heating surface. Two distinct regimes of heat transfer mechanisms were observed during the interval from the step increase of power input to the onset of nucleate boiling: the conduction and convection dominated regimes. The time duration in each regime was considerably shorter with LN2 than with F113, and decreased as heat flux increased, as gravity was reduced, and as the orientation was changed from horizontal up to horizontal down. In transient boiling, boiling initiates at a single point following the step increase in power, and then spreads over the surface. The delay time for the inception of boiling at the first site, and the velocity of spread of boiling varies depending upon the heat flux, orientation, body force, surface roughness and liquid properties, and are a consequence of changes in boundary layer temperature levels associated with changes in natural convection. Following the step increase in power input, surface temperature overshoot and undershoot occur before the steady state boiling temperature level is established.

Boiling points of halogenated ethanes: an explanatory model implicating weak intermolecular hydrogen-halogen bonding.

PubMed

Beauchamp, Guy

2008-10-23

This study explores via structural clues the influence of weak intermolecular hydrogen-halogen bonds on the boiling point of halogenated ethanes. The plot of boiling points of 86 halogenated ethanes versus the molar refraction (linked to polarizability) reveals a series of straight lines, each corresponding to one of nine possible arrangements of hydrogen and halogen atoms on the two-carbon skeleton. A multiple linear regression model of the boiling points could be designed based on molar refraction and subgroup structure as independent variables (R(2) = 0.995, standard error of boiling point 4.2 degrees C). The model is discussed in view of the fact that molar refraction can account for approximately 83.0% of the observed variation in boiling point, while 16.5% could be ascribed to weak C-X...H-C intermolecular interactions. The difference in the observed boiling point of molecules having similar molar refraction values but differing in hydrogen-halogen intermolecular bonds can reach as much as 90 degrees C.

Folate content and retention in commonly consumed vegetables in the South Pacific.

PubMed

Maharaj, Prayna P P; Prasad, Surendra; Devi, Riteshma; Gopalan, Romila

2015-09-01

This paper reports the effect of boiling and frying on the retention of folate in commonly consumed Fijian vegetables (drumstick leaves, taro leaves, bele leaves, amaranth leaves, fern/ota, okra and French bean). The folate content was determined by microbiological assay (Lactobacillus casei rhamnosus) and tri-enzyme (protease, α-amylase and chicken pancreas conjugase) extraction treatment. The folate loss varied among the vegetables from 10-64% on boiling while 1-36% on frying. The higher folate loss was observed during boiling. The folate content in the water derived after boiling different vegetables ranged from 11.9 ± 0.5 to 61.6 ± 2.5 μg/100mL. The folate loss on boiling was accounted for in the cooking water. The predominant way of folate loss on boiling was leaching rather than thermal degradation which makes boiling the better choice of cooking the studied vegetables for folate intake, provided the cooking water is consumed together with the vegetables. Copyright © 2015 Elsevier Ltd. All rights reserved.

Extended hydrodynamic theory of the peak and minimum pool boiling heat fluxes

NASA Technical Reports Server (NTRS)

Linehard, J. H.; Dhir, V. K.

1973-01-01

The hydrodynamic theory of the extreme pool boiling heat fluxes is expanded to embrace a variety of problems that have not previously been analyzed. These problems include the prediction of the peak heat flux on a variety of finite heaters, the influence of viscosity on the Taylor and Helmoltz instability mechanisms with application to film boiling and to the peak heat flux in viscous liquids, the formalization of the analogy between high-current-density electrolysis and boiling, and the description of boiling in the low-gravity limit. The predictions are verified with a large number of new data.

Incorporating Water Boiling in the Numerical Modelling of Thermal Remediation by Electrical Resistance Heating

NASA Astrophysics Data System (ADS)

Molnar, I. L.; Krol, M.; Mumford, K. G.

2017-12-01

Developing numerical models for subsurface thermal remediation techniques - such as Electrical Resistive Heating (ERH) - that include multiphase processes such as in-situ water boiling, gas production and recovery has remained a significant challenge. These subsurface gas generation and recovery processes are driven by physical phenomena such as discrete and unstable gas (bubble) flow as well as water-gas phase mass transfer rates during bubble flow. Traditional approaches to multiphase flow modeling soil remain unable to accurately describe these phenomena. However, it has been demonstrated that Macroscopic Invasion Percolation (MIP) can successfully simulate discrete and unstable gas transport1. This has lead to the development of a coupled Electro Thermal-MIP Model2 (ET-MIP) capable of simulating multiple key processes in the thermal remediation and gas recovery process including: electrical heating of soil and groundwater, water flow, geological heterogeneity, heating-induced buoyant flow, water boiling, gas bubble generation and mobilization, contaminant mass transport and removal, and additional mechanisms such as bubble collapse in cooler regions. This study presents the first rigorous validation of a coupled ET-MIP model against two-dimensional water boiling and water/NAPL co-boiling experiments3. Once validated, the model was used to explore the impact of water and co-boiling events and subsequent gas generation and mobilization on ERH's ability to 1) generate, expand and mobilize gas at boiling and NAPL co-boiling temperatures, 2) efficiently strip contaminants from soil during both boiling and co-boiling. In addition, a quantification of the energy losses arising from steam generation during subsurface water boiling was examined with respect to its impact on the efficacy of thermal remediation. While this study specifically targets ERH, the study's focus on examining the fundamental mechanisms driving thermal remediation (e.g., water boiling) renders these results applicable to a wide range of thermal and gas-based remediation techniques. 1. Mumford, K. G., et al. (2010), Adv. Water Resour. 2010, 33 (4), 504-513. 2. Krol, M. M., et al. (2011), Adv. Water Resour. 2011, 34 (4), 537-549. 3. Hegele, P. R. and Mumford, K. G. Journal of Contaminant Hydrology 2014, 165, 24-36.

A Fundamental Study of Nucleate Pool Boiling Under Microgravity

NASA Technical Reports Server (NTRS)

Ervin, Jamie S.; Merte, Herman, Jr.

1996-01-01

An experimental study of incipient boiling in short-term microgravity and with a/g = +/- 1 for pool boiling was performed. Calibrated thin gold films sputtered on a smoothly polished quartz surface were used simultaneously for thermal-resistance measurements and heating of the boiling surface. The gold films were used for both transient and quasi-steady heating surface temperature measurements. Two test vessels were constructed for precise measurement and control of fluid temperature and pressure: a laboratory pool boiling vessel for the a/g = +/- 1 experiments and a pool boiling vessel designed for the 131 m free-fall in the NASA Lewis Research Center Microgravity Research Facility for the microgravity tests. Measurements included the heater surface temperature, the pressure near the heating surface, the bulk liquid temperatures. High speed photography (up to 1,000 frames per second) was used in the experiments. With high quality microgravity and the measured initial temperature of the quiescent test fluid, R113, the temperature distribution in the liquid at the moment of boiling inception resulting from an imposed step in heat flux is known with a certainty not possible previously. The types of boiling propagation across the large flat heating surface, some observed here for the first time, are categorized; the conditions necessary for their occurrence are described. Explosive boiling propagation with a striking pattern of small scale protuberances over the entire vapor mass periphery not observed previously at low heat flux levels (on the order of 5 W/cm(exp 2)) is described. For the heater surface with a/g = -1, a step in the heater surface temperature of short duration was imposed. The resulting liquid temperature distribution at the moment of boiling inception was different from that obtained with a step in heat flux.

Can we remove iodine-131 from tap water in Japan by boiling? - Experimental testing in response to the Fukushima Daiichi Nuclear Power Plant accident.

PubMed

Tagami, K; Uchida, S

2011-08-01

Iodine-131 concentrations in tap water higher than 100 BqL(-1) were reported by several local governments in Japan following the Fukushima Daiichi Nuclear Power Plant accident. Some individuals in the emergency-response community recommended the boiling of tap water to remove iodine-131. However, the tap water boiling tests in this study showed no iodine-131 loss from the tap water with either short-term boiling (1-10 min) or prolonged boiling (up to 30 min) resulting in up to 3-fold volume reductions. In this situation, boiling was shown to be not effective in removing iodine-131 from tap water; indeed even higher concentrations may result from the liquid-volume reduction accompanying this process. Copyright © 2011 Elsevier Ltd. All rights reserved.

Food-cooking processes modulate allergenic properties of hen's egg white proteins.

PubMed

Liu, Xiaoyu; Feng, Bai-Sui; Kong, Xiaoli; Xu, Hong; Li, Xiumin; Yang, Ping-Chang; Liu, Zhigang

2013-01-01

Reducing the allergenicity of food allergens can suppress the clinical symptoms of food allergy. The objective of the present study was to investigate the effects of processing on the allergenic properties of hen's egg white proteins. Eggs were processed by traditional Chinese cooking, including steaming, water boiling, frying, spicing and tea boiling. The contents of processed egg protein were assessed by sodium dodecyl sulfate polyacrylamide gel electrophoresis; the allergenicity was evaluated by Western blotting, enzyme-linked immunosorbent assay and enzyme allergosorbent test inhibition. Circular dichroism spectrum analysis of four major egg allergens from various egg products was performed as well. A mouse model of food allergy was developed to test the allergenicity of processed egg protein in vivo. Protein degradation was significant following tea boiling and spiced-tea boiling. The total allergenic potential of water-boiled egg and fried egg was relatively higher than that of steamed egg, spiced egg and tea-boiled egg. Challenge with proteins from raw egg, water-boiled egg and fried egg induced skewed T-helper 2 pattern responses (Th2 responses) in the intestine of mice sensitized to egg proteins; however, when the mice sensitized to egg proteins were challenged with proteins from steamed egg, spiced egg and tea-boiled egg, respectively, only weak Th2 responses were induced in their intestine. Processing by steaming, spicing, or tea boiling can weaken the allergenicity of egg proteins. Copyright © 2012 S. Karger AG, Basel.

Transport Phenomena in Fluid Dynamics: Matrix Heat Exchangers and Their Applications in Energy Systems

DTIC Science & Technology

2009-07-01

presented a summary of recent research on boiling in microchannels . He addressed the topics of macro scale versus micro scale heat transfer , two phase...flow regime, flow boiling 14 heat transfer results for microchannels , heat transfer mechanisms in microchannels , and flow boiling models for... Heat Transfer Boiling In Minichannel And Microchannel Flow Passages Of Compact Evaporators, Keynote Lecture Presented at the Engineering Foundation

Criticality in the slowed-down boiling crisis at zero gravity.

PubMed

Charignon, T; Lloveras, P; Chatain, D; Truskinovsky, L; Vives, E; Beysens, D; Nikolayev, V S

2015-05-01

Boiling crisis is a transition between nucleate and film boiling. It occurs at a threshold value of the heat flux from the heater called CHF (critical heat flux). Usually, boiling crisis studies are hindered by the high CHF and short transition duration (below 1 ms). Here we report on experiments in hydrogen near its liquid-vapor critical point, in which the CHF is low and the dynamics slow enough to be resolved. As under such conditions the surface tension is very small, the experiments are carried out in the reduced gravity to preserve the conventional bubble geometry. Weightlessness is created artificially in two-phase hydrogen by compensating gravity with magnetic forces. We were able to reveal the fractal structure of the contour of the percolating cluster of the dry areas at the heater that precedes the boiling crisis. We provide a direct statistical analysis of dry spot areas that confirms the boiling crisis at zero gravity as a scale-free phenomenon. It was observed that, in agreement with theoretical predictions, saturated boiling CHF tends to zero (within the precision of our thermal control system) in zero gravity, which suggests that the boiling crisis may be observed at any heat flux provided the experiment lasts long enough.

Multicomponent gas sorption Joule-Thomson refrigeration

NASA Technical Reports Server (NTRS)

Jones, Jack A. (Inventor); Petrick, S. Walter (Inventor); Bard, Steven (Inventor)

1991-01-01

The present invention relates to a cryogenic Joule-Thomson refrigeration capable of pumping multicomponent gases with a single stage sorption compressor system. Alternative methods of pumping a multicomponent gas with a single stage compressor are disclosed. In a first embodiment, the sorbent geometry is such that a void is defined near the output of the sorption compressor. When the sorbent is cooled, the sorbent primarily adsorbs the higher boiling point gas such that the lower boiling point gas passes through the sorbent to occupy the void. When the sorbent is heated, the higher boiling point gas is desorbed at high temperature and pressure and thereafter propels the lower boiling point gas out of the sorption compressor. A mixing chamber is provided to remix the constituent gases prior to expansion of the gas through a Joule-Thomson valve. Other methods of pumping a multicomponent gas are disclosed. For example, where the sorbent is porous and the low boiling point gas does not adsorb very well, the pores of the sorbent will act as a void space for the lower boiling point gas. Alternatively, a mixed sorbent may be used where a first sorbent component physically adsorbs the high boiling point gas and where the second sorbent component chemically absorbs the low boiling point gas.

Comparison of lipids in organs of the starfish Asterias amurensis associated with different treatments

NASA Astrophysics Data System (ADS)

Wang, Qi; Ikegame, Keita; Takahashi, Koretaro; Xue, Changhu; Zhang, Weinong; Wang, Hongxun; Hou, Wenfu; Wang, Yuming

2013-09-01

Lipids were extracted from organs of the starfish Asterias amurensis associated with different treatments (raw-control, boiling and heating), and then analyzed for lipid content, lipid oxidation index, lipid classes and fatty acid composition. Results showed that boiling softened the hard starfish shells, thus facilitating the collection of starfish organs. As compared with raw organs, the boiled organs had lower water content and higher lipid content, possibly due to the loss of water-holding capacity caused by protein denaturation. Both boiling and heating increased the peroxide value (PV), thiobarbituric acid (TBA) value and carbon value (CV) of lipids. Despite slight increases in the content of complex lipids, associated lipid composition had no substantial variations upon boiling and heating. For simple lipids, the content of 1, 2-diglyceride decreased in boiled and heated organs, with free fatty acids observed on thin layer chromatography (TLC). However, neither boiling nor heating significantly changed the fatty acid compositions of simple or complex lipids in starfish organs, suggesting that these two treatments had no significant effects on complex lipids in starfish organs. Together, our results indicated that boiling of starfish soon after capture facilitated the handling and extraction of useful complex lipids consisting of abundant glucosylceramide and eicosapentaenoic acid (EPA)-bounded phospholipids.

Theoretical modeling of CHF for near-saturated pool boiling and flow boiling from short heaters using the interfacial lift-off criterion

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

Mudawar, I.; Galloway, J.E.; Gersey, C.O.

Pool boiling and flow boiling were examined for near-saturated bulk conditions in order to determine the critical heat flux (CHF) trigger mechanism for each. Photographic studies of the wall region revealed features common to both situations. At fluxes below CHF, the vapor coalesces into a wavy layer which permits wetting only in wetting fronts, the portions of the liquid-vapor interface which contact the wall as a result of the interfacial waviness. Close examination of the interfacial features revealed the waves are generated from the lower edge of the heater in pool boiling and the heater`s upstream region in flow boiling.more » Wavelengths follow predictions based upon the Kelvin-Helmholtz instability criterion. Critical heat flux in both cases occurs when the pressure force exerted upon the interface due to interfacial curvature, which tends to preserve interfacial contact with the wall prior to CHF, is overcome by the momentum of vapor at the site of the first wetting front, causing the interface to lift away from the wall. It is shown this interfacial lift-off criterion facilitates accurate theoretical modeling of CHF in pool boiling and in flow boiling in both straight and curved channels.« less

Film Boiling Heat Transfer Properties of Liquid Hydrogen in Natural Convection

NASA Astrophysics Data System (ADS)

Horie, Y.; Shirai, Y.; Shiotsu, M.; Matsuzawa, T.; Yoneda, K.; Shigeta, H.; Tatsumoto, H.; Hata, K.; Naruo, Y.; Kobayashi, H.; Inatani, Y.

Film boiling heat transfer properties of LH2 for various pressures and subcooling conditions were measured by applying electric current to give an exponential heat input to a PtCo wire with a diameter of 1.2 mm submerged in LH2. The heated wire was set to be horizontal to the ground. The heat transfer coefficient in the film boiling region was higher for higher pressure and higher subcooling. The experimental results are compared with the equation of pool film boiling heat transfer. It is confirmed that the pool film boiling heat transfer coefficients in LH2 can be expressed by this equation.

46 CFR 154.705 - Cargo boil-off as fuel: General.

Code of Federal Regulations, 2010 CFR

2010-10-01

... STANDARDS FOR SELF-PROPELLED VESSELS CARRYING BULK LIQUEFIED GASES Design, Construction and Equipment Cargo Pressure and Temperature Control § 154.705 Cargo boil-off as fuel: General. (a) Each cargo boil-off fuel...

46 CFR 154.705 - Cargo boil-off as fuel: General.

Code of Federal Regulations, 2014 CFR

2014-10-01

... STANDARDS FOR SELF-PROPELLED VESSELS CARRYING BULK LIQUEFIED GASES Design, Construction and Equipment Cargo Pressure and Temperature Control § 154.705 Cargo boil-off as fuel: General. (a) Each cargo boil-off fuel...

46 CFR 154.705 - Cargo boil-off as fuel: General.

Code of Federal Regulations, 2011 CFR

2011-10-01

... STANDARDS FOR SELF-PROPELLED VESSELS CARRYING BULK LIQUEFIED GASES Design, Construction and Equipment Cargo Pressure and Temperature Control § 154.705 Cargo boil-off as fuel: General. (a) Each cargo boil-off fuel...

46 CFR 154.705 - Cargo boil-off as fuel: General.

Code of Federal Regulations, 2013 CFR

2013-10-01

... STANDARDS FOR SELF-PROPELLED VESSELS CARRYING BULK LIQUEFIED GASES Design, Construction and Equipment Cargo Pressure and Temperature Control § 154.705 Cargo boil-off as fuel: General. (a) Each cargo boil-off fuel...

46 CFR 154.705 - Cargo boil-off as fuel: General.

Code of Federal Regulations, 2012 CFR

2012-10-01

... STANDARDS FOR SELF-PROPELLED VESSELS CARRYING BULK LIQUEFIED GASES Design, Construction and Equipment Cargo Pressure and Temperature Control § 154.705 Cargo boil-off as fuel: General. (a) Each cargo boil-off fuel...

Monolithic dual-mode distributed feedback semiconductor laser for tunable continuous-wave terahertz generation.

PubMed

Kim, Namje; Shin, Jaeheon; Sim, Eundeok; Lee, Chul Wook; Yee, Dae-Su; Jeon, Min Yong; Jang, Yudong; Park, Kyung Hyun

2009-08-03

We report on a monolithic dual-mode semiconductor laser operating in the 1550-nm range as a compact optical beat source for tunable continuous-wave (CW) terahertz (THz) generation. It consists of two distributed feedback (DFB) laser sections and one phase section between them. Each wavelength of the two modes can be independently tuned by adjusting currents in micro-heaters which are fabricated on the top of the each DFB section. The continuous tuning of the CW THz emission from Fe(+)-implanted InGaAs photomixers is successfully demonstrated using our dual-mode laser as the excitation source. The CW THz frequency is continuously tuned from 0.17 to 0.49 THz.

On-chip synthesis of circularly polarized emission of light with integrated photonic circuits.

PubMed

He, Li; Li, Mo

2014-05-01

The helicity of circularly polarized (CP) light plays an important role in the light-matter interaction in magnetic and quantum material systems. Exploiting CP light in integrated photonic circuits could lead to on-chip integration of novel optical helicity-dependent devices for applications ranging from spintronics to quantum optics. In this Letter, we demonstrate a silicon photonic circuit coupled with a 2D grating emitter operating at a telecom wavelength to synthesize vertically emitting, CP light from a quasi-TE waveguide mode. Handedness of the emitted circular polarized light can be thermally controlled with an integrated microheater. The compact device footprint enables a small beam diameter, which is desirable for large-scale integration.

Experimental investigation of time and repeated cycles in nucleate pool boiling of alumina/water nanofluid on polished and machined surfaces

NASA Astrophysics Data System (ADS)

Rajabzadeh Dareh, F.; Haghshenasfard, M.; Nasr Esfahany, M.; Salimi Jazi, H.

2018-06-01

Pool boiling heat transfer of pure water and nanofluids on a copper block has been studied experimentally. Nanofluids with various concentrations of 0.0025, 0.005 and 0.01 vol.% are employed and two simple surfaces (polished and machined copper surface) are used as the heating surfaces. The results indicated that the critical heat flux (CHF) in boiling of fluids on the polished surface is 7% higher than CHF on the machined surface. In the case of machined surface, the heat transfer coefficient (HTC) of 0.01 vol.% nanofluid is about 37% higher than HTC of base fluid, while in the polished surface the average HTC of 0.01% nanofluid is about 19% lower than HTC of the pure water. The results also showed that the boiling time and boiling cycles on the polished surface changes the heat transfer performance. By increasing the boiling time from 5 to 10 min, the roughness enhances about 150%, but by increasing the boiling time to 15 min, the roughness enhancement is only 8%.

Direct production of fractionated and upgraded hydrocarbon fuels from biomass

DOEpatents

Felix, Larry G.; Linck, Martin B.; Marker, Terry L.; Roberts, Michael J.

2014-08-26

Multistage processing of biomass to produce at least two separate fungible fuel streams, one dominated by gasoline boiling-point range liquids and the other by diesel boiling-point range liquids. The processing involves hydrotreating the biomass to produce a hydrotreatment product including a deoxygenated hydrocarbon product of gasoline and diesel boiling materials, followed by separating each of the gasoline and diesel boiling materials from the hydrotreatment product and each other.

Microbiological effectiveness of disinfecting water by boiling in rural Guatemala.

PubMed

Rosa, Ghislaine; Miller, Laura; Clasen, Thomas

2010-03-01

Boiling is the most common means of treating water in the home and the benchmark against which alternative point-of-use water treatment options must be compared. In a 5-week study in rural Guatemala among 45 households who claimed they always or almost always boiled their drinking water, boiling was associated with a 86.2% reduction in geometric mean thermotolerant coliforms (TTC) (N = 206, P < 0.0001). Despite consistent levels of fecal contamination in source water, 71.2% of stored water samples from self-reported boilers met the World Health Organization guidelines for safe drinking water (0 TTC/100 mL), and 10.7% fell within the commonly accepted low-risk category of (1-10 TTC/100 mL). As actually practiced in the study community, boiling significantly improved the microbiological quality of drinking water, though boiled and stored drinking water is not always free of fecal contaminations.

Evaluation of correlations of flow boiling heat transfer of R22 in horizontal channels.

PubMed

Zhou, Zhanru; Fang, Xiande; Li, Dingkun

2013-01-01

The calculation of two-phase flow boiling heat transfer of R22 in channels is required in a variety of applications, such as chemical process cooling systems, refrigeration, and air conditioning. A number of correlations for flow boiling heat transfer in channels have been proposed. This work evaluates the existing correlations for flow boiling heat transfer coefficient with 1669 experimental data points of flow boiling heat transfer of R22 collected from 18 published papers. The top two correlations for R22 are those of Liu and Winterton (1991) and Fang (2013), with the mean absolute deviation of 32.7% and 32.8%, respectively. More studies should be carried out to develop better ones. Effects of channel dimension and vapor quality on heat transfer are analyzed, and the results provide valuable information for further research in the correlation of two-phase flow boiling heat transfer of R22 in channels.

Evaluation of Correlations of Flow Boiling Heat Transfer of R22 in Horizontal Channels

PubMed Central

Fang, Xiande; Li, Dingkun

2013-01-01

The calculation of two-phase flow boiling heat transfer of R22 in channels is required in a variety of applications, such as chemical process cooling systems, refrigeration, and air conditioning. A number of correlations for flow boiling heat transfer in channels have been proposed. This work evaluates the existing correlations for flow boiling heat transfer coefficient with 1669 experimental data points of flow boiling heat transfer of R22 collected from 18 published papers. The top two correlations for R22 are those of Liu and Winterton (1991) and Fang (2013), with the mean absolute deviation of 32.7% and 32.8%, respectively. More studies should be carried out to develop better ones. Effects of channel dimension and vapor quality on heat transfer are analyzed, and the results provide valuable information for further research in the correlation of two-phase flow boiling heat transfer of R22 in channels. PMID:23956695

Microbiological Effectiveness of Disinfecting Water by Boiling in Rural Guatemala

PubMed Central

Rosa, Ghislaine; Miller, Laura; Clasen, Thomas

2010-01-01

Boiling is the most common means of treating water in the home and the benchmark against which alternative point-of-use water treatment options must be compared. In a 5-week study in rural Guatemala among 45 households who claimed they always or almost always boiled their drinking water, boiling was associated with a 86.2% reduction in geometric mean thermotolerant coliforms (TTC) (N = 206, P < 0.0001). Despite consistent levels of fecal contamination in source water, 71.2% of stored water samples from self-reported boilers met the World Health Organization guidelines for safe drinking water (0 TTC/100 mL), and 10.7% fell within the commonly accepted low-risk category of (1–10 TTC/100 mL). As actually practiced in the study community, boiling significantly improved the microbiological quality of drinking water, though boiled and stored drinking water is not always free of fecal contaminations. PMID:20207876

Bubble dynamics, two-phase flow, and boiling heat transfer in a microgravity environment

NASA Technical Reports Server (NTRS)

Chung, Jacob N.

1994-01-01

The two-phase bubbly flow and boiling heat transfer in microgravity represents a substantial challenge to scientists and engineers and yet there is an urgent need to seek fundamental understanding in this area for future spacecraft design and space missions. At Washington State University, we have successfully designed, built and tested a 2.1 second drop tower with an innovation airbag deceleration system. Microgravity boiling experiments performed in our 0.6 second Drop Tower produced data flow visualizations that agree with published results and also provide some new understanding concerning flow boiling and microgravity bubble behavior. On the analytical and numerical work, the edge effects of finite divergent electrode plates on the forces experienced by bubbles were investigated. Boiling in a concentric cylinder microgravity and an electric field was numerically predicted. We also completed a feasibility study for microgravity boiling in an acoustic field.

Boiling-induced formation of colloidal gold in black smoker hydrothermal fluids

USGS Publications Warehouse

Gartman, Amy; Hannington, Mark; Jamieson, John W.; Peterkin, Ben; Garbe-Schönberg, Dieter; Findlay, Alyssa J; Fuchs, Sebastian; Kwasnitschka, Tom

2017-01-01

Gold colloids occur in black smoker fluids from the Niua South hydrothermal vent field, Lau Basin (South Pacific Ocean), confirming the long-standing hypothesis that gold may undergo colloidal transport in hydrothermal fluids. Six black smoker vents, varying in temperature from 250 °C to 325 °C, were sampled; the 325 °C vent was boiling at the time of sampling and the 250 °C fluids were diffusely venting. Native gold particles ranging from <50 nm to 2 µm were identified in 4 of the fluid samples and were also observed to precipitate on the sampler during collection from the boiling vent. Total gold concentrations (dissolved and particulate) in the fluid samples range from 1.6 to 5.4 nM in the high-temperature, focused flow vents. Although the gold concentrations in the focused flow fluids are relatively high, they are lower than potential solubilities prior to boiling and indicate that precipitation was boiling induced, with sulfide lost upon boiling to exsolution and metal sulfide formation. Gold concentrations reach 26.7 nM in the 250 °C diffuse flow sample, and abundant native gold particles were also found in the fluids and associated sulfide chimney and are interpreted to be a product of colloid accumulation and growth following initial precipitation upon boiling. These results indicate that colloid-driven precipitation as a result of boiling, the persistence of colloids after boiling, and the accumulation of colloids in diffuse flow fluids are important mechanisms for the enrichment of gold in seafloor hydrothermal systems.

The effect of ginger and garlic addition during cooking on the volatile profile of grass carp (Ctenopharyngodon idella) soup.

PubMed

Li, Jin-Lin; Tu, Zong-Cai; Zhang, Lu; Sha, Xiao-Mei; Wang, Hui; Pang, Juan-Juan; Tang, Ping-Ping

2016-08-01

Ginger and garlic have long been used in Asian countries to enhance the flavor and to neutralize any unpleasant odors present in fish soup. The purpose of this study was to evaluate the change in the amount of volatile components present in fish soup compared to boiled water solutions of ginger and garlic. The fish soup was prepared by boiling oil-fried grass carp ( Ctenopharyngodon idella ) with or without ginger and/or garlic. Generally, boiling garlic and ginger in water led to a decrease in the amount of the principal volatile constituents of these spices, together with the formation of some new volatiles such as pentanal, hexanal, and nonanal. The results showed that 16 terpenes present in raw ginger, predominantly camphene, β -phellandrene, β -citral, α -zingiberene, and ( E )-neral, were detected in fish soup with added ginger and thus remained in the solution even after boiling. Similarly, 2-propen-1-ol and three sulfur compounds (allyl sulfide, diallyl disulfide, and diallyl trisulfide) present in raw garlic, were present in trace amounts in the boiled garlic solution, but were present in considerably larger amounts in the boiled fish solution with garlic or garlic plus ginger. In conclusion, the effect of adding spices on the volatile profile of grass carp soup can be attributed to the dissolution of flavor volatiles mainly derived from raw spices into the solution, with few additional volatiles being formed during boiling. In addition, boiling previously fried grass carp with spices led to enhanced volatile levels compared to boiled spice solutions.

Science 101: Why Does It Take Longer to Boil Potatoes at High Altitudes?

ERIC Educational Resources Information Center

Robertson, Bill

2017-01-01

Why Does It Take Longer to Boil Potatoes at High Altitudes? This column provides background science information for elementary teachers. This month's issue looks at why water boils at different temperatures at different altitudes.

An Investigation of Graduate Scientists' Understandings of Evaporation and Boiling.

ERIC Educational Resources Information Center

Goodwin, Alan; Orlik, Yuri

2000-01-01

Uses a video presentation of six situations relating to the evaporation and boiling of liquids and the escape of dissolved gases from solution and investigates graduate scientists' understanding of the concepts of boiling and evaporation. (Author/YDS)

Pool boiling of water on nano-structured micro wires at sub-atmospheric conditions

NASA Astrophysics Data System (ADS)

Arya, Mahendra; Khandekar, Sameer; Pratap, Dheeraj; Ramakrishna, S. Anantha

2016-09-01

Past decades have seen active research in enhancement of boiling heat transfer by surface modifications. Favorable surface modifications are expected to enhance boiling efficiency. Several interrelated mechanisms such as capillarity, surface energy alteration, wettability, cavity geometry, wetting transitions, geometrical features of surface morphology, etc., are responsible for change in the boiling behavior of modified surfaces. Not much work is available on pool boiling at low pressures on microscale/nanoscale geometries; low pressure boiling is attractive in many applications wherein low operating temperatures are desired for a particular working fluid. In this background, an experimental setup was designed and developed to investigate the pool boiling performance of water on (a) plain aluminum micro wire (99.999 % pure) and, (b) nano-porous alumina structured aluminum micro wire, both having diameter of 250 µm, under sub-atmospheric pressure. Nano-structuring on the plain wire surface was achieved via anodization. Two samples, A and B of anodized wires, differing by the degree of anodization were tested. The heater length scale (wire diameter) was much smaller than the capillary length scale. Pool boiling characteristics of water were investigated at three different sub-atmospheric pressures of 73, 123 and 199 mbar (corresponding to T sat = 40, 50 and 60 °C). First, the boiling characteristics of plain wire were measured. It was noticed that at sub-atmospheric pressures, boiling heat transfer performance for plain wire was quite low due to the increased bubble sizes and low nucleation site density. Subsequently, boiling performance of nano-structured wires (both Sample A and Sample B) was compared with plain wire and it was noted that boiling heat transfer for the former was considerably enhanced as compared to the plain wire. This enhancement is attributed to increased nucleation site density, change in wettability and possibly due to enhanced pore scale evaporation. A preliminary estimation of the bubble growth rates, measured by high speed videography, was undertaken and compared with classical bubble growth rate correlations. It was observed that the average bubble departure sizes on Sample B were larger as compared to plain wire, due to larger surface forces holding the bubble before departure. Bubble condensation in the thermal boundary layer was also captured.

Electric kettles as a source of human lead exposure.

PubMed

Wigle, D T; Charlebois, E J

1978-01-01

Five hundred and seventy-four households in Ottawa were surveyed to evaluate water boiled in electric kettles as a source of lead exposure. Samples of boiled water exceeded the World Health Organization mandatory limit for drinking water (50 microgram/l) in 42.5% of the households. Excessive lead concentrations were observed in 62.8% of water samples from kettles more than 5 years old. Multiple regression analysis indicated that age, sex, and cigarette smoking habits, but not lead concentration in boiled water, nor weekly consumption of boiled water were significantly associated with blood-lead concentration. Lead exposure from electric kettles may be a significant problem only in infants receiving formula prepared with boiled water.

An efficient reliable method to estimate the vaporization enthalpy of pure substances according to the normal boiling temperature and critical properties

PubMed Central

Mehmandoust, Babak; Sanjari, Ehsan; Vatani, Mostafa

2013-01-01

The heat of vaporization of a pure substance at its normal boiling temperature is a very important property in many chemical processes. In this work, a new empirical method was developed to predict vaporization enthalpy of pure substances. This equation is a function of normal boiling temperature, critical temperature, and critical pressure. The presented model is simple to use and provides an improvement over the existing equations for 452 pure substances in wide boiling range. The results showed that the proposed correlation is more accurate than the literature methods for pure substances in a wide boiling range (20.3–722 K). PMID:25685493

An efficient reliable method to estimate the vaporization enthalpy of pure substances according to the normal boiling temperature and critical properties.

PubMed

Mehmandoust, Babak; Sanjari, Ehsan; Vatani, Mostafa

2014-03-01

The heat of vaporization of a pure substance at its normal boiling temperature is a very important property in many chemical processes. In this work, a new empirical method was developed to predict vaporization enthalpy of pure substances. This equation is a function of normal boiling temperature, critical temperature, and critical pressure. The presented model is simple to use and provides an improvement over the existing equations for 452 pure substances in wide boiling range. The results showed that the proposed correlation is more accurate than the literature methods for pure substances in a wide boiling range (20.3-722 K).

Heat Transfer Enhancement due to Bubble Pumping in FC-72 Near the Saturation Temperature

DTIC Science & Technology

1991-03-01

boiling, (2) reducing wall superheat during nucleate boiling and (3) enhancing critical heat flux ( Mudawar , 1990) . Since the heat transfer potential of...flux from a simulated electronic chip attached to the wall of a vertical rectangular channel was determined by Mudawar and Madox (1988). They concluded...Surface Boiling," Industrial and Engineering Chemistry, vol. 41, No. 9, 1949. Mudawar , I., and D.E. Maddox, Critical Heat Flux in Subcooled Flow Boiling

Boiling regimes of impacting drops on a heated substrate under reduced pressure

NASA Astrophysics Data System (ADS)

van Limbeek, Michiel A. J.; Hoefnagels, Paul B. J.; Shirota, Minori; Sun, Chao; Lohse, Detlef

2018-05-01

We experimentally investigate the boiling behavior of impacting ethanol drops on a heated smooth sapphire substrate at pressures ranging from P =0.13 bar to atmospheric pressure. We employ frustrated total internal reflection imaging to study the wetting dynamics of the contact between the drop and the substrate. The spreading drop can be in full contact (contact boiling), it can partially touch (transition boiling), or the drop can be fully levitated (Leidenfrost boiling). We show that the temperature of the boundary between contact and transition boiling shows at most a weak dependence on the impact velocity, but a significant decrease with decreasing ambient gas pressure. A striking correspondence is found between the temperature of this boundary and the static Leidenfrost temperature for all pressures. We therefore conclude that both phenomena share the same mechanism and are dominated by the dynamics taking place at the contact line. On the other hand, the boundary between transition boiling and Leidenfrost boiling, i.e., the dynamic Leidenfrost temperature, increases for increasing impact velocity for all ambient gas pressures. Moreover, the dynamic Leidenfrost temperature coincides for pressures between P =0.13 and 0.54 bar, whereas for atmospheric pressure the dynamic Leidenfrost temperature is slightly elevated. This indicates that the dynamic Leidenfrost temperature is at most weakly dependent on the enhanced evaporation by the lower saturation temperature of the liquid.

Transient nucleate pool boiling in microgravity: Some initial results

NASA Technical Reports Server (NTRS)

Merte, Herman, Jr.; Lee, H. S.; Ervin, J. S.

1994-01-01

Variable gravity provides an opportunity to test the understanding of phenomena which are considered to depend on buoyancy, such as nucleate pool boiling. The active fundamental research in nucleate boiling has sought to determine the mechanisms or physical processes responsible for its high effectiveness, manifested by the high heat flux levels possible with relatively low temperature differences. Earlier research on nucleate pool boiling at high gravity levels under steady conditions demonstrated quantitatively that the heat transfer is degraded as the buoyancy normal to the heater surfaced increases. Correspondingly, it was later shown, qualitatively for short periods of time only, that nucleate boiling heat transfer is enhanced as the buoyancy normal to the heater surface is reduced. It can be deduced that nucleate pool boiling can be sustained as a quasi-steady process provided that some means is available to remove the vapor generated from the immediate vicinity of the heater surface. One of the objectives of the research, the initial results of which are presented here, is to quantify the heat transfer associated with boiling in microgravity. Some quantitative results of nucleate pool boiling in high quality microgravity (a/g approximately 10(exp -5)) of 5s duration, obtained in an evacuated drop tower, are presented here. These experiments were conducted as precursors of longer term space experiments. A transient heating technique is used, in which the heater surface is a transparent gold film sputtered on a qua rtz substrate, simultaneously providing the mean surface temperature from resistance thermometry and viewing of the boiling process both from beneath and across the surface. The measurement of the transient mean heater surface temperature permits the computation, by numerical means, of the transient mean heat transfer coefficient. The preliminary data obtained demonstrates that a quasi-steady boiling process can occur in microgravity if the bulk liquid subcooling is sufficiently high and if the imposed heat flux is sufficiently low. This is attributed to suface tension effects at the liquid-vapor-solid junction causing rewetting to take place, sustaining the nucleate boiling. Otherwise, dryout at the heater surface will occur, as observed.

PHYSICAL PROPERTIES OF FLUORINATED PROPANE AND BUTANE DERIVATIVES AS ALTERNATIVE REFRIGERANTS

EPA Science Inventory

Physical property measurements are presented for 24 fluorinated propane and butane derivatives and one fluorinated ether. These measurements include melting point, boiling point, vapor pressure below the boiling point, heat of vaporization at the boiling point, critical propertie...

Possible Mechanism for Formation of Nonwettable "Dry Spots" on a Heated Surface during Nucleate Pool Boiling: II. Feedwater Stop Regime

NASA Astrophysics Data System (ADS)

Zhukov, Yu. M.; Urtenov, D. S.

2017-12-01

The problems of simulation of heterogeneous nucleate pool boiling on a horizontal surface on the ascending branch of the boiling curve from the formation of a steam lens (SL) to the boiling crisis are considered. The proposed hypothesis provides in a number of cases a logically consistent interpretation of experiments and outlines the organizational principle of transferring the wall-liquid-steam system into the regime of nonwettable "dry spot" formation. The model includes the following types of nucleate boiling: (a) cyclic boiling with the contact line reverse to the bubble bottom center and bubble departure from the surface (at low heat flux q and the contact angle θ < 90°); (b) single steam bubble conversion into a steam lens, i.e., local film boiling with the possibility of spreading of a single "dry spot" at the variation of the contact angle θ ≥ 90°, and substantial growth of the departure diameter D d and SL lifetime τd; (c) formation of a single steam cluster of four SLs at a given pressure, the liquid underheating, and the average wall overheating.

Impact of Fe powder sintering and soldering in production of porous heating surface on flow boiling heat transfer in minichannels

NASA Astrophysics Data System (ADS)

Depczyński, Wojciech; Piasecki, Artur; Piasecka, Magdalena; Strąk, Kinga

2017-10-01

This paper focuses on identification of the impact of porous heated surface on flow boiling heat transfer in a rectangular minichannel. The heated element for Fluorinert FC-72 was a thin plate made of Haynes-230. Infrared thermography was used to determine changes in the temperature on its outer smooth side. The porous surface in contact with the fluid in the minichannel was produced in two processes: sintering or soldering of Fe powder to the plate. The results were presented as relationships between the heat transfer coefficient and the distance from the minichannel inlet and as boiling curves. Results obtained for using a smooth heated plate at the saturated boiling region were also presented to compare. In the subcooled boiling region, at a higher heat flux, the heat transfer coefficient was slightly higher for the surface prepared via soldering. In the saturated boiling region, the local heat transfer coefficients obtained for the smooth plate surface were slightly higher than those achieved from the sintered plate surface. The porous structures formed have low thermal conductivity. This may induce noticeable thermal resistance at the diffusion bridges of the sintered structures, in particular within the saturated boiling region.

Sensory quality and appropriateness of raw and boiled Jerusalem artichoke tubers (Helianthus tuberosus L.).

PubMed

Bach, Vibe; Kidmose, Ulla; Thybo, Anette K; Edelenbos, Merete

2013-03-30

The aim of the present study was to investigate the sensory attributes, dry matter and sugar content of five varieties of Jerusalem artichoke tubers and their relation to the appropriateness of the tubers for raw and boiled preparation. Sensory evaluation of raw and boiled Jerusalem artichoke tubers was performed by a trained sensory panel and a semi-trained consumer panel of 49 participants, who also evaluated the appropriateness of the tubers for raw and boiled preparation. The appropriateness of raw Jerusalem artichoke tubers was related to Jerusalem artichoke flavour, green nut flavour, sweetness and colour intensity, whereas the appropriateness of boiled tubers was related to celeriac aroma, sweet aroma, sweetness and colour intensity. In both preparations the variety Dwarf stood out from the others by being the least appropriate tuber. A few sensory attributes can be used as predictors of the appropriateness of Jerusalem artichoke tubers for raw and boiled consumption. Knowledge on the quality of raw and boiled Jerusalem artichoke tubers can be used to inform consumers on the right choice of raw material and thereby increase the consumption of the vegetable. © 2012 Society of Chemical Industry.

Film boiling of mercury droplets

NASA Technical Reports Server (NTRS)

Baumeister, K. J.; Schoessow, G. J.; Chmielewski, C. E.

1975-01-01

Vaporization times of mercury droplets in Leidenfrost film boiling on a flat horizontal plate are measured in an air atmosphere. Extreme care was used to prevent large amplitude droplet vibrations and surface wetting; therefore, these data can be compared to film boiling theory. Diffusion from the upper surface of the drop appears as a dominant mode of mass transfer from the drop. A closed-form analytical film boiling theory is developed to account for the diffusive evaporation. Reasonable agreement between data and theory is seen.

Stability and potency of raw and boiled shrimp extracts for skin prick test.

PubMed

Pariyaprasert, Wipada; Piboonpocanun, Surapon; Jirapongsananuruk, Orathai; Visitsunthorn, Nualanong

2015-06-01

The difference of stability between raw and boiled shrimp extracts used in prick tests has never been investigated despite its potential consequences in tests development. The aim of this study was to compare the raw and boiled shrimp extracts of two species; Macrobrachium rosenbergii (freshwater shrimp) and Penaeus monodon (seawater shrimp) held at 4 ?C for different periods of time for their stability and potency in vivo by using the skin prick test (SPT) method. Raw and boiled M. rosenbergii and P. monodon extracts were prepared and stored at 4 ?C for 1, 7, 14 and 30 days. Thirty patients were pricked with raw and boiled shrimp extracts at all storage times, as well as prick to prick skin test (PTP) to fresh raw and boiled shrimps of both species. The mean wheal diameter (MWD) resulting from prick tests for all shrimp extracts was measured and compared. The shrimp extracts of all storage times yielded positive skin test results in the range of 90% - 100%. Raw P. monodon extracts induced larger wheals than boiled extracts at all storage times. There was no significant difference of MWD between raw and boiled M. rosenbergii extracts on day 1, 7, and 14. Significant correlations between MWD of PTP to fresh shrimps and SPT to all shrimp extracts were observed. All shrimp extracts were sterile at all storage times. Raw and boiled M. rosenbergii and P. monodon extracts were stable and sterile at 4 ?C for at most 30 days. SPT with these extracts induced more than 10 mm in shrimp allergy patients and the results were comparable with PTP to fresh shrimps.

Correlation of physical properties with molecular structure for some dicyclic hydrocarbons having high thermal-energy release per unit volume -- 2-alkylbiphenyl and the two isomeric 2-alkylbicyclohexyl series

NASA Technical Reports Server (NTRS)

Goodman, Irving A; Wise, Paul H

1952-01-01

Three homologous series of related dicyclic hydrocarbons are presented for comparison on the basis of their physical properties, which include net heat of combustion, density, melting point, boiling point, and kinematic viscosity. The three series investigated include the 2-n-alkylbiphenyl, 2-n-alkylbicyclohexyl (high boiling), and 2-n-alkylbiphenyls (low boiling) series through c sub 16, in addition to three branched-chain (isopropyl, sec-butyl, and isobutyl) 2-alkylbiphenyls and their corresponding 2-alkylbicyclohexyls. The physical properties of the low-boiling and high-boiling isomers of 2-sec-butylbicyclohexyl and 2-isobutylbicyclohexyl are reported herein for the first time.

Detection of vapor nanobubbles by small angle neutron scattering (SANS)

NASA Astrophysics Data System (ADS)

Popov, Emilian; He, Lilin; Dominguez-Ontiveros, Elvis; Melnichenko, Yuri

2018-04-01

Experiments using boiling water on untreated (roughness 100-300 nm) metal surfaces using small-angle neutron scattering (SANS) show the appearance of structures that are 50-70 nm in size when boiling is present. The scattering signal disappears when the boiling ceases, and no change in the signal is detected at any surface temperature condition below saturation. This confirms that the signal is caused by vapor nanobubbles. Two boiling regimes are evaluated herein that differ by the degree of subcooling (3-10 °C). A polydisperse spherical model with a log-normal distribution fits the SANS data well. The size distribution indicates that a large number of nanobubbles exist on the surface during boiling, and some of them grow into large bubbles.

Pretest thermal analysis of the Tuff Water Migration/In-Situ Heater Experiment

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

Bulmer, B.M.

This report describes the pretest thermal analysis for the Tuff Water Migration/In-Situ Heater Experiment to be conducted in welded tuff in G-tunnel, Nevada Test Site. The parametric thermal modeling considers variable boiling temperature, tuff thermal conductivity, tuff emissivity, and heater operating power. For nominal tuff properties, some near field boiling is predicted for realistic operating power. However, the extent of boiling will be strongly determined by the ambient (100% water saturated) rock thermal conductivity. In addition, the thermal response of the heater and of the tuff within the dry-out zone (i.e., bounded by boiling isotherm) is dependent on the temperaturemore » variation of rock conductivity as well as the extent of induced boiling.« less

17. RW Meyer Sugar Mill: 18761889. Boiling House, 1878. View: ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

17. RW Meyer Sugar Mill: 1876-1889. Boiling House, 1878. View: Southwest corner of boiling house. The amimal-powered cane mill is located in the undergrowth in the right foreground, - R. W. Meyer Sugar Mill, State Route 47, Kualapuu, Maui County, HI

Structural changes of malt proteins during boiling.

PubMed

Jin, Bei; Li, Lin; Liu, Guo-Qin; Li, Bing; Zhu, Yu-Kui; Liao, Liao-Ning

2009-03-09

Changes in the physicochemical properties and structure of proteins derived from two malt varieties (Baudin and Guangmai) during wort boiling were investigated by differential scanning calorimetry, SDS-PAGE, two-dimensional electrophoresis, gel filtration chromatography and circular dichroism spectroscopy. The results showed that both protein content and amino acid composition changed only slightly during boiling, and that boiling might cause a gradual unfolding of protein structures, as indicated by the decrease in surface hydrophobicity and free sulfhydryl content and enthalpy value, as well as reduced alpha-helix contents and markedly increased random coil contents. It was also found that major component of both worts was a boiling-resistant protein with a molecular mass of 40 kDa, and that according to the two-dimensional electrophoresis and SE-HPLC analyses, a small amount of soluble aggregates might be formed via hydrophobic interactions. It was thus concluded that changes of protein structure caused by boiling that might influence beer quality are largely independent of malt variety.

Comparison of direct boiling method with commercial kits for extracting fecal microbiome DNA by Illumina sequencing of 16S rRNA tags.

PubMed

Peng, Xin; Yu, Ke-Qiang; Deng, Guan-Hua; Jiang, Yun-Xia; Wang, Yu; Zhang, Guo-Xia; Zhou, Hong-Wei

2013-12-01

Low cost and high throughput capacity are major advantages of using next generation sequencing (NGS) techniques to determine metagenomic 16S rRNA tag sequences. These methods have significantly changed our view of microorganisms in the fields of human health and environmental science. However, DNA extraction using commercial kits has shortcomings of high cost and time constraint. In the present study, we evaluated the determination of fecal microbiomes using a direct boiling method compared with 5 different commercial extraction methods, e.g., Qiagen and MO BIO kits. Principal coordinate analysis (PCoA) using UniFrac distances and clustering showed that direct boiling of a wide range of feces concentrations gave a similar pattern of bacterial communities as those obtained from most of the commercial kits, with the exception of the MO BIO method. Fecal concentration by boiling method affected the estimation of α-diversity indices, otherwise results were generally comparable between boiling and commercial methods. The operational taxonomic units (OTUs) determined through direct boiling showed highly consistent frequencies with those determined through most of the commercial methods. Even those for the MO BIO kit were also obtained by the direct boiling method with high confidence. The present study suggested that direct boiling could be used to determine the fecal microbiome and using this method would significantly reduce the cost and improve the efficiency of the sample preparation for studying gut microbiome diversity. © 2013 Elsevier B.V. All rights reserved.

Initial fuel temperature effects on burning rate of pool fire.

PubMed

Chen, Bing; Lu, Shou-Xiang; Li, Chang-Hai; Kang, Quan-Sheng; Lecoustre, Vivien

2011-04-15

The influence of the initial fuel temperature on the burning behavior of n-heptane pool fire was experimentally studied at the State Key Laboratory of Fire Science (SKLFS) large test hall. Circular pool fires with diameters of 100mm, 141 mm, and 200 mm were considered with initial fuel temperatures ranging from 290 K to 363 K. Burning rate and temperature distributions in fuel and vessel wall were recorded during the combustion. The burning rate exhibited five typical stages: initial development, steady burning, transition, bulk boiling burning, and decay. The burning rate during the steady burning stage was observed to be relatively independent of the initial fuel temperature. In contrast, the burning rate of the bulk boiling burning stage increases with increased initial fuel temperature. It was also observed that increased initial fuel temperature decreases the duration of steady burning stage. When the initial temperature approaches the boiling point, the steady burning stage nearly disappears and the burning rate moves directly from the initial development stage to the transition stage. The fuel surface temperature increases to its boiling point at the steady burning stage, shortly after ignition, and the bulk liquid reaches boiling temperature at the bulk boiling burning stage. No distinguished cold zone is formed in the fuel bed. However, boiling zone is observed and the thickness increases to its maximum value when the bulk boiling phenomena occurs. Copyright © 2011 Elsevier B.V. All rights reserved.

Numerical and Experimental Study of Mechanisms Involved in Boiling Histotripsy.

PubMed

Pahk, Ki Joo; Gélat, Pierre; Sinden, David; Dhar, Dipok Kumar; Saffari, Nader

2017-12-01

The aim of boiling histotripsy is to mechanically fractionate tissue as an alternative to thermal ablation for therapeutic applications. In general, the shape of a lesion produced by boiling histotripsy is tadpole like, consisting of a head and a tail. Although many studies have demonstrated the efficacy of boiling histotripsy for fractionating solid tumors, the exact mechanisms underpinning this phenomenon are not yet well understood, particularly the interaction of a boiling vapor bubble with incoming incident shockwaves. To investigate the mechanisms involved in boiling histotripsy, a high-speed camera with a passive cavitation detection system was used to observe the dynamics of bubbles produced in optically transparent tissue-mimicking gel phantoms exposed to the field of a 2.0-MHz high-intensity focused ultrasound (HIFU) transducer. We observed that boiling bubbles were generated in a localized heated region and cavitation clouds were subsequently induced ahead of the expanding bubble. This process was repeated with HIFU pulses and eventually resulted in a tadpole-shaped lesion. A simplified numerical model describing the scattering of the incident ultrasound wave by a vapor bubble was developed to help interpret the experimental observations. Together with the numerical results, these observations suggest that the overall size of a lesion induced by boiling histotripsy is dependent on the sizes of (i) the heated region at the HIFU focus and (ii) the backscattered acoustic field by the original vapor bubble. Copyright © 2017 World Federation for Ultrasound in Medicine and Biology. Published by Elsevier Inc. All rights reserved.

Nutrient changes and antinutrient contents of beniseed and beniseed soup during cooking using a Nigerian traditional method.

PubMed

Agiang, M A; Umoh, I B; Essien, A I; Eteng, M U

2010-10-15

Evaluations of the effect of prolong cooking on the nutrient and antinutrient composition ofbeniseed and beniseed soup were carried out in this study. Proximate, mineral, vitamin A and C and antinutrient compositions of raw beniseed (BS-R), beniseed boiled (BSB) for 15, 30, 45 and 60 min and beniseed soup (BSS) cooked for the same intervals of time were assessed. Results of the proximate composition analyses showed that raw and boiled beniseed had lower moisture content (5.39-5.51%) than beniseed soups (10.06-15.20%). Nitrogen-free extract (total carbohydrates), fats and phosphorus contents were improved in both the boiled beniseed and beniseed soup while calcium and potassium were increased in the boiled seeds and soup samples respectively. Moisture (in the raw and boiled beniseed), ash, magnesium, zinc, iron contents in both the seed and soup were unchanged in all the samples. Vitamins A and C levels of both boiled beniseed and beniseed soup samples were reduced with increase in cooking time. Beniseed soup had higher protein contents than both the raw and boiled beniseed which decreased with increase in cooking time. Beniseed samples provided good sources of energy (572.97-666.05 kcal/100 g). Except for phytate, the levels of antinutrients tested were lower in the raw and boiled beniseed than in the soup samples which decreased with increase in cooking time. The results are discussed with reference to the effect of prolonged cooking on the nutrient requirements of consumers.

Effects of preparation methods on protein and amino acid contents of various eggs available in Malaysian local markets.

PubMed

Ismail, Maznah; Mariod, Abdalbasit; Pin, Sia Soh

2013-01-01

The effect of preparation methods (raw, half-boiled and hard-boiled) on protein and amino acid contents, as well as the protein quality (amino acid score) of regular, kampung and nutrient enriched Malaysian eggs was investigated. The protein content was determined using a semi-micro Kjeldahl method whereas the amino acid composition was determined using HPLC. The protein content of raw regular, kampung and nutrient enriched eggs were 49.9 ±0.2%, 55.8 ±0.2% and 56.5 ±0.5%, respectively. The protein content of hard-boiled eggs of regular, kampung and nutrient enriched eggs was 56.8 ±0.1%, 54.7 ±0.1%, and 53.7 ±0.5%, while that for half-boiled eggs of regular, kampung and nutrient enriched eggs was 54.7 ±0.6%, 53.4 ±0.4%, and 55.1 ±0.7%, respectively. There were significant differences (p < 0.05) in protein and amino acid contents of half-boiled, hard-boiled as compared with raw samples, and valine was found as the limiting amino acid. It was found that there were significant differences (p < 0.05) of total amino score in regular, kampung and nutrient enriched eggs after heat treatments.Furthermore, hard-boiling (100°C) for 10 minutes and half-boiling (100°C) for 5 minutes affects the total amino score, which in turn alter the protein quality of the egg.

Anti-obesity effects of boiled tuna extract in mice with obesity induced by a high-fat diet.

PubMed

Kim, Youngmin; Kwon, Mi-Jin; Choi, Jeong-Wook; Lee, Min-Kyeong; Kim, Chorong; Jung, Jaehun; Aprianita, Heny; Nam, Heesop; Nam, Taek-Jeong

2016-10-01

The aim of this study was to examine the anti-obesity effects of boiled tuna extract in C57BL/6N mice with obesity induced by a high-fat diet (HFD). We determined the anti-obesity effects of boiled tuna extract (100, 200, or 400 mg/kg) on the progression of HFD-induced obesity for 10 weeks. The mice were divided into 5 groups as follows: the normal diet (ND) group (n=10); the HFD group (n=10); the mice fed HFD and 100 mg/kg boiled tuna extract group (n=10); those fed a HFD and 200 mg/kg boiled tuna extract group (n=10); and those fed a HFD and 400 mg/kg boiled tuna extract group (n=10). Changes in body weight, fat content, serum lipid levels and lipogenic enzyme levels were measured. The consumption of boiled tuna extract lowered epididymal tissue weight and exerted anti-obesity effects, as reflected by the serum glucose, triglyceride (TG), total cholesterol (TC), high-density lipoprotein cholesterol (HDL‑C), low-density lipoprotein cholesterol (LDL-C), insulin and leptin levels. In addition, we demonstrated changes in liver adipogenic- and lipogenic-related protein expression by western blot analysis. Boiled tuna extract downregulated the levels of the CCAAT/enhancer-binding protein α, β and δ (C/EBPα, β, δ), and peroxisome proliferator-activated receptor-γ (PPAR-γ) adipocyte marker genes. Boiled tuna extract also attenuated adipogenic and lipogenic gene expression, namely the levels of fatty acid synthase (FAS), lipoprotein lipase (LPL), acetyl-CoA carboxylase (ACC), glucose transporter type 4 (Glut4) and phosphorylated adenosine monophosphate-activated protein kinase α and β (AMPKα, β) in a dose-dependent manner. Moreover, the consumption of boiled tuna extract restored the levels of superoxide dismutase (SOD), catalase (CAT), glutamic oxaloacetic transaminase (GOT), glutamic-pyruvate transaminase (GPT), aspartate transaminase (AST) and alanine transaminase (ALT) to those of the control group. These results suggest that boiled tuna extract attenuates the progression of obesity by stimulating fatty acid oxidation through the upregulation of AMPK genes, as well as by inhibiting the synthesis of adipogenic and lipogenic enzymes. These characteristics of boiled tuna extract highlight its potential anti-obesity effects.

10 CFR 50.55a - Codes and standards.

Code of Federal Regulations, 2011 CFR

2011-01-01

... specified in § 50.55, except that each combined license for a boiling or pressurized water-cooled nuclear... boiling or pressurized water-cooled nuclear power facility is subject to the conditions in paragraphs (f... performed. (2) Systems and components of boiling and pressurized water-cooled nuclear power reactors must...

Assessment of in situ butanol recovery by vacuum during acetone butanol ethanol (ABE) fermentation

USDA-ARS?s Scientific Manuscript database

Butanol fermentation is product limiting due to butanol toxicity to microbial cells. Butanol (boiling point: 118 deg C) boils at a greater temperature than water (boiling point: 100 deg C) and application of vacuum technology to integrated acetone-butanol-ethanol (ABE) fermentation and recovery may ...

Investigation on the heat transfer characteristics during flow boiling of liquefied natural gas in a vertical micro-fin tube

NASA Astrophysics Data System (ADS)

Xu, Bin; Shi, Yumei; Chen, Dongsheng

2014-03-01

This paper presents an experimental investigation on the heat transfer characteristics of liquefied natural gas flow boiling in a vertical micro-fin tube. The effect of heat flux, mass flux and inlet pressure on the flow boiling heat transfer coefficients was analyzed. The Kim, Koyama, and two kinds of Wellsandt correlations with different Ftp coefficients were used to predict the flow boiling heat transfer coefficients. The predicted results showed that the Koyama correlation was the most accurate over the range of experimental conditions.

Occurrence of nitrate, nitrite and volatile nitrosamines in certain feedstuffs and animal products.

PubMed

Ologhobo, A D; Adegede, H I; Maduagiwu, E N

1996-01-01

Nitrate, nitrite and nitrosamines were analysed in poultry feeds, meat and eggs. The poultry meat was boiled and roasted while the eggs were raw and boiled, and the effects of these processing treatments on the level of these compounds were investigated. Nitrate levels in the meat samples were significantly (P < 0.05) reduced by boiling and roasting, with boiling being more effective. Nitrite levels were also reduced significantly by processing (P < 0.05). The feed samples contained levels of nitrate which were significantly different (P < 0.05) from one producer to another. Nitrite levels were generally low in all feed samples. Nitrosamines were not detected in any of the feed samples and in the meat samples except in two samples of boiled meat which contained 0.001 g/kg each.

20. RW Meyer Sugar Mill: 18761889. Boiling House Interior, 1878. ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

20. RW Meyer Sugar Mill: 1876-1889. Boiling House Interior, 1878. View: Remains of south wall. The molasses storage pits are below the floor in the foreground. The remaining piece of floor indicates the form of the entire floor. The sorghum pan and boiling range flue slope from left to right (east to west) and permitted batches of cane juice to flow through the boiling pan by gravity. The beams, joists, truss work are built of northwest pine. The sides and floor boards are built of redwood. The boiling range flue is built of fire-brick, masonry, and portland cement. The corrugated roof appears to be a later addition, not contemporary with mill operation. - R. W. Meyer Sugar Mill, State Route 47, Kualapuu, Maui County, HI

Capillary hydrodynamics and transport processes during phase change in microscale systems

NASA Astrophysics Data System (ADS)

Kuznetsov, V. V.

2017-09-01

The characteristics of two-phase gas-liquid flow and heat transfer during flow boiling and condensing in micro-scale heat exchangers are discussed in this paper. The results of numerical simulation of the evaporating liquid film flowing downward in rectangular minichannel of the two-phase compact heat exchanger are presented and the peculiarities of microscale heat transport in annular flow with phase changes are discussed. Presented model accounts the capillarity induced transverse flow of liquid and predicts the microscale heat transport processes when the nucleate boiling becomes suppressed. The simultaneous influence of the forced convection, nucleate boiling and liquid film evaporation during flow boiling in plate-fin heat exchangers is considered. The equation for prediction of the flow boiling heat transfer at low flux conditions is presented and verified using experimental data.

Nutrition content of brisket point end of part Simental Ongole Crossbred meat in boiled various temperature

NASA Astrophysics Data System (ADS)

Riyanto, J.; Sudibya; Cahyadi, M.; Aji, A. P.

2018-01-01

This aim of this study was to determine the quality of nutritional contents of beef brisket point end of Simental Ongole Crossbred meat in various boiling temperatures. Simental Ongole Crossbred had been fattened for 9 months. Furthermore, they were slaughtered at slaughterhouse and brisket point end part of meat had been prepared to analyse its nutritional contents using Food Scan. These samples were then boiled at 100°C for 0 (TR), 15 (R15), and 30 (R30) minutes, respectively. The data was analysed using Randomized Complete Design (CRD) and Duncan’s multiple range test (DMRT) had been conducted to differentiate among three treatments. The results showed that boiling temperatures significantly affected moisture, and cholesterol contents of beef (P<0.05) while fat content was not significantly affected by boiling temperatures. The boiling temperature decreased beef water contents from 72.77 to 70.84%, on the other hand, the treatment increased beef protein and cholesterol contents from 20.77 to 25.14% and 47.55 to 50.45 mg/100g samples, respectively. The conclusion of this study was boiling of beef at 100°C for 15 minutes and 30 minutes decreasing water content and increasing protein and cholesterol contents of brisket point end of Simental Ongole Crossbred beef.

Controlled tissue emulsification produced by high intensity focused ultrasound shock waves and millisecond boiling

PubMed Central

Khokhlova, Tatiana D.; Canney, Michael S.; Khokhlova, Vera A.; Sapozhnikov, Oleg A.; Crum, Lawrence A.; Bailey, Michael R.

2011-01-01

In high intensity focused ultrasound (HIFU) applications, tissue may be thermally necrosed by heating, emulsified by cavitation, or, as was recently discovered, emulsified using repetitive millisecond boiling caused by shock wave heating. Here, this last approach was further investigated. Experiments were performed in transparent gels and ex vivo bovine heart tissue using 1, 2, and 3 MHz focused transducers and different pulsing schemes in which the pressure, duty factor, and pulse duration were varied. A previously developed derating procedure to determine in situ shock amplitudes and the time-to-boil was refined. Treatments were monitored using B-mode ultrasound. Both inertial cavitation and boiling were observed during exposures, but emulsification occurred only when shocks and boiling were present. Emulsified lesions without thermal denaturation were produced with shock amplitudes sufficient to induce boiling in less than 20 ms, duty factors of less than 0.02, and pulse lengths shorter than 30 ms. Higher duty factors or longer pulses produced varying degrees of thermal denaturation combined with mechanical emulsification. Larger lesions were obtained using lower ultrasound frequencies. The results show that shock wave heating and millisecond boiling is an effective and reliable way to emulsify tissue while monitoring the treatment with ultrasound. PMID:22088025

Enhancement of Pool Boiling Heat Transfer and Control of Bubble Motion in Microgravity Using Electric Fields - BCOEL

NASA Technical Reports Server (NTRS)

Herman, Cila; Iacona, Estelle; Acquaviva, Tom; Coho, Bill; Grant, Nechelle; Nahra, Henry; Sankaran, Subramanian; Taylor, Al; Julian, Ed; Robinson, Dale;

The changes of astaxanthin content and chemical characteristics of tiger prawn (Penaeus monodon) due to processing: boiling, smoking and frying

NASA Astrophysics Data System (ADS)

Swastawati, F.

2018-03-01

Food processing using high temperatures can cause changes in pigment color and chemical characteristics in food stuffs, including prawn. The aim of this research was to evaluate the changes in pigment and chemical characteristics of tiger prawn caused by boiling, smoking and frying. Ten kg of tiger prawn was boiled, smoked and fried at the temperature of ± 100 °C for ± 10 min. The results showed that boiling, smoking and frying gave a significant effect (P < 0.05) on the astaxanthin pigment, pH, moisture, protein, salt content, Aw and color. The content of astaxanthin pigments in fresh prawn, boiled prawn, smoked prawn and fried prawn was: 132.79 ± 1.5 μg·g-1 82.89 ± 0.92 μg·g-1 78.28 ± 0.1 μg·g-1 and 91.35 ± 2.59 μg·g-1, respectively. The value of °Hue on fresh prawn, boiled prawn, smoked prawn and fried prawn was: 87.85° 52.5° 55.94° and 53.98°. The tiger prawn processed by the smoking method has preferable by panelist rather than processed by boiling and frying.

Infrared thermometry study of nanofluid pool boiling phenomena

PubMed Central

2011-01-01

Infrared thermometry was used to obtain first-of-a-kind, time- and space-resolved data for pool boiling phenomena in water-based nanofluids with diamond and silica nanoparticles at low concentration (<0.1 vol.%). In addition to macroscopic parameters like the average heat transfer coefficient and critical heat flux [CHF] value, more fundamental parameters such as the bubble departure diameter and frequency, growth and wait times, and nucleation site density [NSD] were directly measured for a thin, resistively heated, indium-tin-oxide surface deposited onto a sapphire substrate. Consistent with other nanofluid studies, the nanoparticles caused deterioration in the nucleate boiling heat transfer (by as much as 50%) and an increase in the CHF (by as much as 100%). The bubble departure frequency and NSD were found to be lower in nanofluids compared with water for the same wall superheat. Furthermore, it was found that a porous layer of nanoparticles built up on the heater surface during nucleate boiling, which improved surface wettability compared with the water-boiled surfaces. Using the prevalent nucleate boiling models, it was possible to correlate this improved surface wettability to the experimentally observed reductions in the bubble departure frequency, NSD, and ultimately to the deterioration in the nucleate boiling heat transfer and the CHF enhancement. PMID:21711754

Predictors of Drinking Water Boiling and Bottled Water Consumption in Rural China: A Hierarchical Modeling Approach.

PubMed

Cohen, Alasdair; Zhang, Qi; Luo, Qing; Tao, Yong; Colford, John M; Ray, Isha

2017-06-20

Approximately two billion people drink unsafe water. Boiling is the most commonly used household water treatment (HWT) method globally and in China. HWT can make water safer, but sustained adoption is rare and bottled water consumption is growing. To successfully promote HWT, an understanding of associated socioeconomic factors is critical. We collected survey data and water samples from 450 rural households in Guangxi Province, China. Covariates were grouped into blocks to hierarchically construct modified Poisson models and estimate risk ratios (RR) associated with boiling methods, bottled water, and untreated water. Female-headed households were most likely to boil (RR = 1.36, p < 0.01), and among boilers those using electric kettles rather than pots had higher income proxies (e.g., per capita TV ownership RR = 1.42, p < 0.01). Higher-income households with younger, literate, and male heads were more likely to purchase (frequently contaminated) bottled water, or use electric kettles if they boiled. Our findings show that boiling is not an undifferentiated practice, but one with different methods of varying effectiveness, environmental impact, and adoption across socioeconomic strata. Our results can inform programs to promote safer and more efficient boiling using electric kettles, and suggest that if rural China's economy continues to grow then bottled water use will increase.

Enhancement of Pool Boiling Heat Transfer and Control of Bubble Motion in Microgravity Using Electric Fields (BCOEL)

NASA Technical Reports Server (NTRS)

Herman, Cila; Iacona, Estelle; Acquaviva, Tom; Coho, Bill; Grant, Nechelle; Nahra, Henry; Taylor, Al; Julian, Ed; Robinson, Dale; VanZandt, Dave

2001-01-01

The BCOEL project focuses on improving pool boiling heat transfer and bubble control in microgravity by exposing the fluid to electric fields. The electric fields induce a body force that can replace gravity in the low gravity environment, and enhance bubble removal from the heated surface. A better understanding of microgravity effects on boiling with and without electric fields is critical to the proper design of the phase-change-heat-removal equipment for use in spacebased applications. The microgravity experiments will focus on the visualization of bubble formation and shape during boiling. Heat fluxes on the boiling surface will be measured, and, together with the measured driving temperature differences, used to plot boiling curves for different electric field magnitudes. Bubble formation and boiling processes were found to be extremely sensitive to g-jitter. The duration of the experimental run is critical in order to achieve steady state in microgravity experiments. The International Space Station provides conditions suitable for such experiments. The experimental apparatus to be used in the study is described in the paper. The apparatus will be tested in the KC-135 first, and microgravity experiments will be conducted on board of the International Space Station using the Microgravity Science Glovebox as the experimental platform.

Distributed feedback laser diode integrated with distributed Bragg reflector for continuous-wave terahertz generation.

PubMed

Kim, Namje; Han, Sang-Pil; Ryu, Han-Cheol; Ko, Hyunsung; Park, Jeong-Woo; Lee, Donghun; Jeon, Min Yong; Park, Kyung Hyun

2012-07-30

A widely tunable dual mode laser diode with a single cavity structure is demonstrated. This novel device consists of a distributed feedback (DFB) laser diode and distributed Bragg reflector (DBR). Micro-heaters are integrated on the top of each section for continuous and independent wavelength tuning of each mode. By using a single gain medium in the DFB section, an effective common optical cavity and common modes are realized. The laser diode shows a wide tunability of the optical beat frequency, from 0.48 THz to over 2.36 THz. Continuous wave THz radiation is also successfully generated with low-temperature grown InGaAs photomixers from 0.48 GHz to 1.5 THz.

Flexible metal patterning in glass microfluidic structures using femtosecond laser direct-write ablation followed by electroless plating

NASA Astrophysics Data System (ADS)

Xu, Jian; Midorikawa, Katsumi; Sugioka, Koji

2014-03-01

A simple and flexible technique for integrating metal micropatterns into glass microfluidic structures based on threedimensional femtosecond laser microfabrication is presented. Femtosecond laser direct writing followed by thermal treatment and successive chemical etching allows us to fabricate three-dimensional microfluidic structures such as microchannels and microreservoirs inside photosensitive glass. Then, the femtosecond laser direct-write ablation followed by electroless metal plating enables space-selective deposition of patterned metal films on desired locations of internal walls of the fabricated microfluidic structures. The developed technique is applied to integrate a metal microheater into a glass microchannel to control the temperature of liquid samples in the channel, which can be used as a microreactor for enhancement of chemical reactions.

A microfluidic microreactor for the synthesis of gold nanorods.

PubMed

Day, Daniel; Gu, Min

2009-03-11

A microfluidic microreactor for the synthesis of gold nanorods is fabricated using femtosecond pulse laser microfabrication techniques. Femtosecond pulse lasers are able to etch a wide range of materials that are required for a microreactor, from the photomasks to the microheaters. The heating of the fluid in the microreactor is achieved through the design and fabrication of a microscale heating element incorporated onto the bottom surface of the microreactor which is capable of reaching temperatures greater than 130 degrees C. Computational fluid dynamic simulations of the heating profile of an optimized microreactor show increased heating performance with respect to a serpentine microreactor. The synthesis of gold nanorods is demonstrated in the optimized microreactor, based on a flow rate of 0.5 microg min(-1).

Wide-range and fast thermally-tunable silicon photonic microring resonators using the junction field effect.

PubMed

Wang, Xiaoxi; Lentine, Anthony; DeRose, Christopher; Starbuck, Andrew L; Trotter, Douglas; Pomerene, Andrew; Mookherjea, Shayan

2016-10-03

Tunable silicon microring resonators with small, integrated micro-heaters which exhibit a junction field effect were made using a conventional silicon-on-insulator (SOI) photonic foundry fabrication process. The design of the resistive tuning section in the microrings included a "pinched" p-n junction, which limited the current at higher voltages and inhibited damage even when driven by a pre-emphasized voltage waveform. Dual-ring filters were studied for both large (>4.9 THz) and small (850 GHz) free-spectral ranges. Thermal red-shifting was demonstrated with microsecond-scale time constants, e.g., a dual-ring filter was tuned over 25 nm in 0.6 μs 10%-90% transition time, and with efficiency of 3.2 μW/GHz.

Optical microfiber-loaded surface plasmonic TE-pass polarizer

NASA Astrophysics Data System (ADS)

Ma, Youqiao; Farrell, Gerald; Semenova, Yuliya; Li, Binghui; Yuan, Jinhui; Sang, Xinzhu; Yan, Binbin; Yu, Chongxiu; Guo, Tuan; Wu, Qiang

2016-04-01

We propose a novel optical microfiber-loaded plasmonic TE-pass polarizer consisting of an optical microfiber placed on top of a silver substrate and demonstrate its performance both numerically by using the finite element method (FEM) and experimentally. The simulation results show that the loss in the fundamental TE mode is relatively low while at the same time the fundamental TM mode suffers from a large metal dissipation loss induced by excitation of the microfiber-loaded surface plasmonic mode. The microfiber was fabricated using the standard microheater brushing-tapering technique. The measured extinction ratio over the range of the C-band wavelengths is greater than 20 dB for the polarizer with a microfiber diameter of 4 μm, which agrees well with the simulation results.

Influence of Boiling Duration of GCSB-5 on Index Compound Content and Antioxidative and Anti-inflammatory Activity.

PubMed

Lee, In-Hee; Chung, Hwa-Jin; Shin, Joon-Shik; Ha, In-Hyuk; Kim, Me-Riong; Koh, Wonil; Lee, Jinho

2017-01-01

GCSB-5, an herbal drug composition with an anti-inflammatory effect, is prepared by boiling, which is the most common herbal extraction method in traditional Korean medicine. Several parameters are involved in the process, i.e., extractant type, herb-to-extractant ratio, extraction temperature and pressure, and total boiling time. The aim of this study was to examine the influence of boiling time on index compound amount and the antioxidative and anti-inflammatory activities of GCSB-5. Different samples of GCSB-5 were obtained by decocting for 30, 60, 90, 120, 150, and 240 min. Each sample was tested for hydrogen ion concentration (pH), total soluble solid content (TSSC), marker compound profiles, and antioxidative and anti-inflammatory activity. pH was found to decrease while TSSC increased with extended decoction. Marker compound contents for GCSB-5 (acanthoside D for Acanthopanax sessiliflorus Seem, 20-hydroxyecdysone for Achyranthes japonica Nakai, and pinoresinol diglucoside for Eucommia ulmoides Oliver) remained relatively constant regardless of the length of boiling. Total D-glucose amount increased with longer boiling. The antioxidative and anti-inflammatory potentials of GCSB-5 were not substantially affected by decoction duration. Biological characteristics and marker compound content of GCSB-5 were not altered significantly in prolonged boiling. Longer boiling duration of GCSB-5 did not increase yield in a time-dependent manner, but yields of 210 and 240 min samples were significantly higherHydrogen ion concentration of GCSB-5 samples decreased while total soluble solid content and D-glucose concentration levels increased with boiling durationAlthough concentrations of some index compounds increased with extended boiling duration of GCSB-5, increase was small and not in a direct proportional relationshipAntioxidative and anti-inflammatory properties of GCSB-5 were not substantially affected by decoction duration. Abbreviations used: CAM: Complementary and alternative medicine; KIOM: Korea Institute of Oriental Medicine; KMD: Korean medicine doctor; TSSC: Total soluble solid content; pH: Hydrogen ion concentration; HPLC: High-performance liquid chromatography; NO: Nitric oxide; NO 2 : Nitric dioxide; LPS: Lipopolysaccharide; DMSO: Dimethyl sulfoxide.

Incidence and recurrence of boils and abscesses within the first year: a cohort study in UK primary care

PubMed Central

Shallcross, Laura J; Hayward, Andrew C; Johnson, Anne M; Petersen, Irene

2015-01-01

Background Boils and abscesses are common in primary care but the burden of recurrent infection is unknown. Aim To investigate the incidence of and risk factors for recurrence of boil or abscess for individuals consulting primary care. Design and setting Cohort study using electronic health records from primary care in the UK. Method The Health Improvement Network (THIN) database was used to identify patients who had consulted their GP for a boil or abscess. Poisson regression was used to examine the relationship between age, sex, social deprivation, and consultation and to calculate the incidence of, and risk factors for, repeat consultation for a boil or abscess. Results Overall, 164 461 individuals were identified who consulted their GP for a boil or abscess between 1995 and 2010. The incidence of first consultation for a boil or abscess was 512 (95% CI = 509 to 515) per 100 000 person-years in females and 387 (95% CI = 385 to 390) per 100 000 person-years in males. First consultations were most frequent in younger age groups (16–34 years) and those with the greatest levels of social deprivation. The rate of repeat consultation for a new infection during follow up was 107.5 (95% confidence interval [CI] = 105.6 to 109.4) per 1000 person-years. Obesity (relative risk [RR] 1.3, 95% CI = 1.2 to 1.3), diabetes (RR 1.3, 95% CI = 1.2 to 1.3), smoking (RR 1.3, 95% CI = 1.2 to 1.4), age <30 years (RR 1.2, 95% CI = 1.2 to 1.3), and prior antibiotic use (RR 1.4, 95% CI = 1.3–1.4) were all associated with repeat consultation for a boil or abscess. Conclusion Ten percent of patients with a boil or abscess develop a repeat boil or abscess within 12 months. Obesity, diabetes, young age, smoking, and prescription of an antibiotic in the 6 months before initial presentation were independently associated with recurrent infection, and may represent options for prevention. PMID:26412844

Assessing the microbiological performance and potential cost of boiling drinking water in urban Zambia.

PubMed

Psutka, Rebecca; Peletz, Rachel; Michelo, Sandford; Kelly, Paul; Clasen, Thomas

2011-07-15

Boiling is the most common method of disinfecting water in the home and the benchmark against which other point-of-use water treatment is measured. In a six-week study in peri-urban Zambia, we assessed the microbiological effectiveness and potential cost of boiling among 49 households without a water connection who reported "always" or "almost always" boiling their water before drinking it. Source and household drinking water samples were compared weekly for thermotolerant coliforms (TTC), an indicator of fecal contamination. Demographics, costs, and other information were collected through surveys and structured observations. Drinking water samples taken at the household (geometric mean 7.2 TTC/100 mL, 95% CI, 5.4-9.7) were actually worse in microbiological quality than source water (geometric mean 4.0 TTC/100 mL, 95% CI, 3.1-5.1) (p < 0.001), although both are relatively low levels of contamination. Only 60% of drinking water samples were reported to have actually been boiled at the time of collection from the home, suggesting over-reporting and inconsistent compliance. However, these samples were of no higher microbiological quality. Evidence suggests that water quality deteriorated after boiling due to lack of residual protection and unsafe storage and handling. The potential cost of fuel or electricity for boiling was estimated at 5% and 7% of income, respectively. In this setting where microbiological water quality was relatively good at the source, safe-storage practices that minimize recontamination may be more effective in managing the risk of disease from drinking water at a fraction of the cost of boiling.

Boiling behavior of sodium-potassium alloy in a bench-scale solar receiver

NASA Astrophysics Data System (ADS)

Moreno, J. B.; Andraka, C. E.; Moss, T. A.

During 1989-90, a 75-kW(sub t) sodium reflux pool-boiler solar receiver was successfully demonstrated at Sandia National Laboratories. Significant features of this receiver include the following: (1) boiling sodium as the heat transfer medium, and (2) electric-discharge-machined (EDM) cavities as artificial nucleation sites to stabilize boiling. Since this first demonstration, design of a second-generation pool-boiler receiver that will bring the concept closer to commercialization has begun. For long life, the new receiver uses Haynes Alloy 230. For increased safety factors against film boiling and flooding, it has a refined shape and somewhat larger dimensions. To eliminate the need for trace heating, the receiver will boil the sodium-potassium alloy NaK-78 instead of sodium. To reduce manufacturing costs, it will use one of a number of alternatives to EDM cavities for stabilization of boiling. To control incipient-boiling superheats, especially during hot restarts, it will contain a small amount of inert gas. Before the new receiver design could be finalized, bench-scale tests of some of the proposed changes were necessary. A series of bench-scale pool boilers were built from Haynes Alloy 230 and filled with NaK-78. Various boiling-stabilizer candidates were incorporated into them, including laser-drilled cavities and a number of different sintered-powder-metal coatings. These bench-scale pool boilers have been operated at temperatures up to 750 C, heated by quartz lamps with incident radiant fluxes up to 95 W/sq cm. The effects of various orientations and added gases have been studied. Results of these studies are presented.

Teaching Structure-Property Relationships: Investigating Molecular Structure and Boiling Point

ERIC Educational Resources Information Center

Murphy, Peter M.

2007-01-01

A concise, well-organized table of the boiling points of 392 organic compounds has facilitated inquiry-based instruction in multiple scientific principles. Many individual or group learning activities can be derived from the tabulated data of molecular structure and boiling point based on the instructor's education objectives and the students'…

16 CFR 1511.5 - Structural integrity tests.

Code of Federal Regulations, 2012 CFR

2012-01-01

... pounds for an additional 10 seconds. (c) Heat cycle deterioration. After the testing prescribed in... pacifier in boiling water for 5 minutes and then remove the pacifier and allow it to cool for 5 minutes in... in the boiling water for 5 minutes. The process shall be repeated for a total of 6 boiling/cooling...

16 CFR 1511.5 - Structural integrity tests.

Code of Federal Regulations, 2011 CFR

2011-01-01

... pounds for an additional 10 seconds. (c) Heat cycle deterioration. After the testing prescribed in... pacifier in boiling water for 5 minutes and then remove the pacifier and allow it to cool for 5 minutes in... in the boiling water for 5 minutes. The process shall be repeated for a total of 6 boiling/cooling...

16 CFR § 1511.5 - Structural integrity tests.

Code of Federal Regulations, 2013 CFR

2013-01-01

... pounds for an additional 10 seconds. (c) Heat cycle deterioration. After the testing prescribed in... pacifier in boiling water for 5 minutes and then remove the pacifier and allow it to cool for 5 minutes in... in the boiling water for 5 minutes. The process shall be repeated for a total of 6 boiling/cooling...

16 CFR 1511.5 - Structural integrity tests.

Code of Federal Regulations, 2014 CFR

2014-01-01

... pounds for an additional 10 seconds. (c) Heat cycle deterioration. After the testing prescribed in... pacifier in boiling water for 5 minutes and then remove the pacifier and allow it to cool for 5 minutes in... in the boiling water for 5 minutes. The process shall be repeated for a total of 6 boiling/cooling...

Acoustic Behavior of Vapor Bubbles

NASA Technical Reports Server (NTRS)

Prosperetti, Andrea; Oguz, Hasan N.

1996-01-01

In a microgravity environment vapor bubbles generated at a boiling surface tend to remain near it for a long time. This affects the boiling heat transfer and in particular promotes an early transition to the highly inefficient film boiling regime. This paper describes the physical basis underlying attempts to remove the bubbles by means of pressure radiation forces.

78 FR 63516 - Initial Test Program of Emergency Core Cooling Systems for New Boiling-Water Reactors

Federal Register 2010, 2011, 2012, 2013, 2014

2013-10-24

... NUCLEAR REGULATORY COMMISSION [NRC-2012-0134] Initial Test Program of Emergency Core Cooling....79.1, ``Initial Test Program of Emergency Core Cooling Systems for New Boiling-Water Reactors.'' This... emergency core cooling systems (ECCSs) for boiling- water reactors (BWRs) whose licenses are issued after...

Evaporation, Boiling and Bubbles

ERIC Educational Resources Information Center

Goodwin, Alan

2012-01-01

Evaporation and boiling are both terms applied to the change of a liquid to the vapour/gaseous state. This article argues that it is the formation of bubbles of vapour within the liquid that most clearly differentiates boiling from evaporation although only a minority of chemistry textbooks seems to mention bubble formation in this context. The…

Generation of shockwave and vortex structures at the outflow of a boiling water jet

NASA Astrophysics Data System (ADS)

Alekseev, M. V.; Lezhnin, S. I.; Pribaturin, N. A.; Sorokin, A. L.

2014-12-01

Results of numerical simulation for shock waves and generation of vortex structures during unsteady outflow of boiling liquid jet are presented. The features of evolution of shock waves and vortex structures formation during unsteady outflow of boiling water are compared with corresponding structures during unsteady gas outflow.

Early Onset of Nucleate Boiling on Gas-covered Biphilic Surfaces.

PubMed

Shen, Biao; Yamada, Masayuki; Hidaka, Sumitomo; Liu, Jiewei; Shiomi, Junichiro; Amberg, Gustav; Do-Quang, Minh; Kohno, Masamichi; Takahashi, Koji; Takata, Yasuyuki

2017-05-17

For phase-change cooling schemes for electronics, quick activation of nucleate boiling helps safeguard the electronics components from thermal shocks associated with undesired surface superheating at boiling incipience, which is of great importance to the long-term system stability and reliability. Previous experimental studies show that bubble nucleation can occur surprisingly early on mixed-wettability surfaces. In this paper, we report unambiguous evidence that such unusual bubble generation at extremely low temperatures-even below the boiling point-is induced by a significant presence of incondensable gas retained by the hydrophobic surface, which exhibits exceptional stability even surviving extensive boiling deaeration. By means of high-speed imaging, it is revealed that the consequently gassy boiling leads to unique bubble behaviour that stands in sharp contrast with that of pure vapour bubbles. Such findings agree qualitatively well with numerical simulations based on a diffuse-interface method. Moreover, the simulations further demonstrate strong thermocapillary flows accompanying growing bubbles with considerable gas contents, which is associated with heat transfer enhancement on the biphilic surface in the low-superheat region.

Hydrolysis of Glycosidic Flavonoids during the Preparation of Danggui Buxue Tang: An Outcome of Moderate Boiling of Chinese Herbal Mixture

PubMed Central

Zhang, Wendy Li; Chen, Jian-Ping; Lam, Kelly Yin-Ching; Zhan, Janis Ya-Xian; Yao, Ping; Dong, Tina Ting-Xia; Tsim, Karl Wah-Keung

2014-01-01

Chemical change during boiling of herbal mixture is a puzzle. By using Danggui Buxue Tang (DBT), a herbal decoction that contains Astragali Radix (AR) and Angelicae Sinensis Radix (ASR), we developed a model in analyzing the hydrolysis of flavonoid glycosides during the boiling of herbal mixture in water. A proper preparation of DBT is of great benefit to the complete extraction of bioactive ingredients. Boiling of DBT in water increased the solubility of AR-derived astragaloside IV, calycosin, formononetin, calycosin-7-O-β-D-glucoside, and ononin in a time- and temperature-dependent manner: the amounts of these chemicals reached a peak at 2 h. The glycosidic resides of AR, calycosin-7-O-β-D-glucoside, and ononin could be hydrolyzed during the moderate boiling process to form calycosin and formononetin, respectively. The hydrolysis efficiency was strongly affected by pH, temperature, and amount of herbs. Interestingly, the preheated herbs were not able to show this hydrolytic activity. The current results supported the rationality of ancient preparation of DBT in boiling water by moderate heat. PMID:24744813

Nucleate pool boiling: High gravity to reduced gravity; liquid metals to cryogens

NASA Technical Reports Server (NTRS)

Merte, Herman, Jr.

1988-01-01

Requirements for the proper functioning of equipment and personnel in reduced gravity associated with space platforms and future space station modules introduce unique problems in temperature control; power generation; energy dissipation; the storage, transfer, control and conditioning of fluids; and liquid-vapor separation. The phase change of boiling is significant in all of these. Although both pool and flow boiling would be involved, research results to date include only pool boiling because buoyancy effects are maximized for this case. The effective application of forced convection boiling heat transfer in the microgravity of space will require a well grounded and cogent understanding of the mechanisms involved. Experimental results are presented for pool boiling from a single geometrical configuration, a flat surface, covering a wide range of body forces from a/g = 20 to 1 to a/g = 0 to -1 for a cryogenic liquid, and from a/g = 20 to 1 for water and a liquid metal. Similarities in behavior are noted for these three fluids at the higher gravity levels, and may reasonably be expected to continue at reduced gravity levels.

Cooking impact in color, pigments and volatile composition of grapevine leaves (Vitis vinifera L. var. Malvasia Fina and Touriga Franca).

PubMed

Lima, Adriano; Pereira, José Alberto; Baraldi, Ilton; Malheiro, Ricardo

2017-04-15

Grapevine leaves (Vitis vinifera L. var. Malvasia Fina and Touriga Franca) under culinary treatment (blanching and boiling at 60, 75 and 90min) were studied for their color, pigments and volatile fraction changes. Blanching and boiling caused a decrease in luminosity and a loss of green coloration in both varieties, while a yellow-brownish color arose. Significant correlations were established between the loss of green color (monochromatic variable a ∗ ) and the total chlorophylls content. The main volatiles in fresh leaves [(Z)-3-hexenal, (Z)-3-hexen-1-ol, and (Z)-3-hexenyl acetate] were drastically reduced by blanching and suppressed by boiling. Other compounds like pentanal and 6-methyl-5-hepten-2 one arose from blanching and boiling. A boiling time of 60min is adequate for the culinary process of grapevine leaves, since the product is considered edible and the pigments and volatile changes are not as drastic as observed at 75 and 90min of boiling. Copyright © 2016 Elsevier Ltd. All rights reserved.

Dryout-type critical heat flux in vertical upward annular flow: effects of entrainment rate, initial entrained fraction and diameter

NASA Astrophysics Data System (ADS)

Wu, Zan; Wadekar, Vishwas; Wang, Chenglong; Sunden, Bengt

2018-01-01

This study aims to reveal the effects of liquid entrainment, initial entrained fraction and tube diameter on liquid film dryout in vertical upward annular flow for flow boiling. Entrainment and deposition rates of droplets were included in mass conservation equations to estimate the local liquid film mass flux in annular flow, and the critical vapor quality at dryout conditions. Different entrainment rate correlations were evaluated using flow boiling data of water and organic liquids including n-pentane, iso-octane and R134a. Effect of the initial entrained fraction (IEF) at the churn-to-annular flow transition was also investigated. A transitional Boiling number was proposed to separate the IEF-sensitive region at high Boiling numbers and the IEF-insensitive region at low Boiling numbers. Besides, the diameter effect on dryout vapor quality was studied. The dryout vapor quality increases with decreasing tube diameter. It needs to be pointed out that the dryout characteristics of submillimeter channels might be different because of different mechanisms of dryout, i.e., drying of liquid film underneath long vapor slugs and flow boiling instabilities.

Formation and Growth of Micro and Macro Bubbles on Copper-Graphite Composite Surfaces

NASA Technical Reports Server (NTRS)

Chao, David F.; Sankovic, John M.; Motil, Brian J.; Zhang, Nengli

2007-01-01

Micro scale boiling behavior in the vicinity of graphite micro-fiber tips on the coppergraphite composite boiling surfaces is investigated. It is discovered that a large number of micro bubbles are formed first at the micro scratches and cavities on the copper matrix in pool boiling. In virtue of the non-wetting property of graphite, once the growing micro bubbles touch the graphite tips, the micro bubbles are sucked by the tips and merged into larger micro bubbles sitting on the tips. The micro bubbles grow rapidly and coalesce to form macro bubbles, each of which sitting on several tips. The growth processes of the micro and macro bubbles are analyzed and formulated followed by an analysis of bubble departure on the composite surfaces. Based on these analyses, the enhancement mechanism of the pool boiling heat transfer on the composite surfaces is clearly revealed. Experimental results of pool boiling heat transfer both for water and Freon-113 on the composite surfaces convincingly demonstrate the enhancement effects of the unique structure of Cu-Gr composite surfaces on boiling heat transfer.

Decontamination of chlorantraniliprole residues on cabbage and cauliflower through household processing methods.

PubMed

Kar, Abhijit; Mandal, Kousik; Singh, Balwinder

2012-04-01

A supervised field trial was conducted to study the residues of chlorantraniliprole on cabbage and cauliflower. Three applications of chlorantraniliprole at 10 days interval were made @ 9.25 and 18.50 g a.i. ha(-1). The samples of marketable size heads and curds of cabbage and cauliflower were collected at 0 and 1 day after the last application. QuEChERS sample preparation was used for the determination of chlorantraniliprole residues on cabbage heads and cauliflower curds. The residues of chlorantraniliprole were quantified by high performance liquid chromatography (HPLC) with photo diode array (PDA) detector and confirmed by high performance thin layer chromatography (HPTLC). Washing of cabbage and cauliflower with tap water removed about 17%-40% of chlorantraniliprole residues. However, boiling removed 100% of chlorantraniliprole residues on cabbage and cauliflower in both the cases.

Experimental study of flash boiling spray vaporization through quantitative vapor concentration and liquid temperature measurements

NASA Astrophysics Data System (ADS)

Zhang, Gaoming; Hung, David L. S.; Xu, Min

2014-08-01

Flash boiling sprays of liquid injection under superheated conditions provide the novel solutions of fast vaporization and better air-fuel mixture formation for internal combustion engines. However, the physical mechanisms of flash boiling spray vaporization are more complicated than the droplet surface vaporization due to the unique bubble generation and boiling process inside a superheated bulk liquid, which are not well understood. In this study, the vaporization of flash boiling sprays was investigated experimentally through the quantitative measurements of vapor concentration and liquid temperature. Specifically, the laser-induced exciplex fluorescence technique was applied to distinguish the liquid and vapor distributions. Quantitative vapor concentration was obtained by correlating the intensity of vapor-phase fluorescence with vapor concentration through systematic corrections and calibrations. The intensities of two wavelengths were captured simultaneously from the liquid-phase fluorescence spectra, and their intensity ratios were correlated with liquid temperature. The results show that both liquid and vapor phase of multi-hole sprays collapse toward the centerline of the spray with different mass distributions under the flash boiling conditions. Large amount of vapor aggregates along the centerline of the spray to form a "gas jet" structure, whereas the liquid distributes more uniformly with large vortexes formed in the vicinity of the spray tip. The vaporization process under the flash boiling condition is greatly enhanced due to the intense bubble generation and burst. The liquid temperature measurements show strong temperature variations inside the flash boiling sprays with hot zones present in the "gas jet" structure and vortex region. In addition, high vapor concentration and closed vortex motion seem to have inhibited the heat and mass transfer in these regions. In summary, the vapor concentration and liquid temperature provide detailed information concerning the heat and mass transfer inside flash boiling sprays, which is important for the understanding of its unique vaporization process.

Experimental Study of Subcooled Flow Boiling Heat Transfer on a Smooth Surface in Short-Term Microgravity

NASA Astrophysics Data System (ADS)

Zhang, Yonghai; Liu, Bin; Zhao, Jianfu; Deng, Yueping; Wei, Jinjia

2018-06-01

The flow boiling heat transfer characteristics of subcooled air-dissolved FC-72 on a smooth surface (chip S) were studied in microgravity by utilizing the drop tower facility in Beijing. The heater, with dimensions of 40 × 10 × 0.5 mm3 (length × width × thickness), was combined with two silicon chips with the dimensions of 20 × 10 × 0.5 mm3. High-speed visualization was used to supplement observation in the heat transfer and vapor-liquid two-phase flow characteristics. In the low and moderate heat fluxes region, the flow boiling of chip S at inlet velocity V = 0.5 m/s shows almost the same regulations as that in pool boiling. All the wall temperatures at different positions along the heater in microgravity are slightly lower than that in normal gravity, which indicates slight heat transfer enhancement. However, in the high heat flux region, the pool boiling of chip S shows much evident deterioration of heat transfer compared with that of flow boiling in microgravity. Moreover, the bubbles of flow boiling in microgravity become larger than that in normal gravity due to the lack of buoyancy Although the difference of the void fraction in x-y plain becomes larger with increasing heat flux under different gravity levels, it shows nearly no effect on heat transfer performance except for critical heat flux (CHF). Once the void fraction in y-z plain at the end of the heater equals 1, the vapor blanket will be formed quickly and transmit from downstream to upstream along the heater, and CHF occurs. Thus, the height of channel is an important parameter to determine CHF in microgravity at a fixed velocity. The flow boiling of chip S at inlet velocity V = 0.5 m/s shows higher CHF than that of pool boiling because of the inertia force, and the CHF under microgravity is about 78-92% of that in normal gravity.

Nucleate Boiling Heat Transfer Studied Under Reduced-Gravity Conditions

NASA Technical Reports Server (NTRS)

Chao, David F.; Hasan, Mohammad M.

2000-01-01

Boiling is known to be a very efficient mode of heat transfer, and as such, it is employed in component cooling and in various energy-conversion systems. In space, boiling heat transfer may be used in thermal management, fluid handling and control, power systems, and on-orbit storage and supply systems for cryogenic propellants and life-support fluids. Recent interest in the exploration of Mars and other planets and in the concept of in situ resource utilization on the Martian and Lunar surfaces highlights the need to understand how gravity levels varying from the Earth's gravity to microgravity (1g = or > g/g(sub e) = or > 10(exp -6)g) affect boiling heat transfer. Because of the complex nature of the boiling process, no generalized prediction or procedure has been developed to describe the boiling heat transfer coefficient, particularly at reduced gravity levels. Recently, Professor Vijay K. Dhir of the University of California at Los Angeles proposed a novel building-block approach to investigate the boiling phenomena in low-gravity to microgravity environments. This approach experimentally investigates the complete process of bubble inception, growth, and departure for single bubbles formed at a well-defined and controllable nucleation site. Principal investigator Professor Vijay K. Dhir, with support from researchers from the NASA Glenn Research Center at Lewis Field, is performing a series of pool boiling experiments in the low-gravity environments of the KC 135 microgravity aircraft s parabolic flight to investigate the inception, growth, departure, and merger of bubbles from single- and multiple-nucleation sites as a function of the wall superheat and the liquid subcooling. Silicon wafers with single and multiple cavities of known characteristics are being used as test surfaces. Water and PF5060 (an inert liquid) were chosen as test liquids so that the role of surface wettability and the magnitude of the effect of interfacial tension on boiling in reduced gravity can be investigated.

Study to evaluate the impact of heat treatment on water soluble vitamins in milk.

PubMed

Asadullah; Khair-un-nisa; Tarar, Omer Mukhtar; Ali, Syed Abdul; Jamil, Khalid; Begum, Askari

2010-11-01

To evaluate the effect of domestic boiling practice on the contents of water soluble vitamins of loose milk and quantitative comparison of these vitamins in Ultra High Temperature (UHT) treated packaged milk with that of boiled loose milk. Loose milk samples were collected from various localities of Karachi city (Pakistan). These samples were boiled in simulated household conditions for 5, 10 and 15 minutes. Ultra High Temperature (UHT) treated packaged milk samples of various brands were obtained from the local market. The aliquots were analyzed for water-soluble vitamins using High Performance Liquid Chromatography (HPLC) technique. The mean values and standard deviations for data were computed and compared as well as level of variations were also determined. Conventional boiling caused destruction of water soluble vitamins in milk i.e. vitamin 81 content in fresh milk decreased from 0.037 mg/100 g to 0.027 mg/100 g after 15 min boiling, whereas vitamin B2 from 0.115 to 0.084 mg/100 g, vitamin B3 0.062 to 0.044 mg/100 g, vitamin B6 0.025 to 0.019 mg/100 g and folic acid 3.38 to 2.40 microg/100 g. This accounted for a post-boiling decrease of about 27, 27, 29, 24 and 36% in vitamins B1, B2, B3, B6 and folic acid respectively. The values for vitamins B1, B2, B3, B6 and folic acid determined in boiled milk were significantly lower than UHT treated packaged milk samples by 25.9, 75.0, 54.5, 63.16 and 38.1% respectively. Conventional boiling caused drastic reduction in vitamin levels of loose milk samples. In comparison to this, UHT milk retained high levels of water soluble B-vitamins. Thus it could be envisaged that UHT treated milk provides better water soluble vitamins' nourishment than conventionally boiled milk (JPMA 60:909; 2010).

Subcooled flow boiling critical heat flux (CHF) and its application to fusion energy components. Part II. A review of microconvective, experimental, and correlational aspects

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

Boyd, R.D.

Microconvective, instability, experimental, and correlational aspects of subcooled flow boiling critical heat flux (CHF) are summarized. The present understanding of CHF in subcooled flow boiling is reviewed and research directions that will permit the accommodation of higher heat fluxes are outlined. This survey (Parts I and II), which contains a representative coverage of the literature over the last 30 years, is concerned only with CHF in the subcooled flow boiling regime, and unless otherwise noted, all references to CHF are confined to that regime.

Identification of quantitative trait loci associated with boiled seed hardness in soybean

PubMed Central

Hirata, Kaori; Masuda, Ryoichi; Tsubokura, Yasutaka; Yasui, Takeshi; Yamada, Tetsuya; Takahashi, Koji; Nagaya, Taiko; Sayama, Takashi; Ishimoto, Masao; Hajika, Makita

2014-01-01

Boiled seed hardness is an important factor in the processing of soybean food products such as nimame and natto. Little information is available on the genetic basis for boiled seed hardness, despite the wide variation in this trait. DNA markers linked to the gene controlling this trait should be useful in soybean breeding programs because of the difficulty of its evaluation. In this report, quantitative trait locus (QTL) analysis was performed to reveal the genetic factors associated with boiled seed hardness using a recombinant inbred line population developed from a cross between two Japanese cultivars, ‘Natto-shoryu’ and ‘Hyoukei-kuro 3’, which differ largely in boiled seed hardness, which in ‘Natto-shoryu’ is about twice that of ‘Hyoukei-kuro 3’. Two significantly stable QTLs, qHbs3-1 and qHbs6-1, were identified on chromosomes 3 and 6, for which the ‘Hyoukei-kuro 3’ alleles contribute to decrease boiled seed hardness for both QTLs. qHbs3-1 also showed significant effects in progeny of a residual heterozygous line and in a different segregating population. Given its substantial effect on boiled seed hardness, SSR markers closely linked to qHbs3-1, such as BARCSOYSSR_03_0165 and BARCSOYSSR_03_0185, could be useful for marker-assisted selection in soybean breeding. PMID:25914591

10 CFR Appendix A to Part 52 - Design Certification Rule for the U.S. Advanced Boiling Water Reactor

Code of Federal Regulations, 2010 CFR

2010-01-01

... Water Reactor A Appendix A to Part 52 Energy NUCLEAR REGULATORY COMMISSION (CONTINUED) LICENSES... Rule for the U.S. Advanced Boiling Water Reactor I. Introduction Appendix A constitutes the standard design certification for the U.S. Advanced Boiling Water Reactor (ABWR) design, in accordance with 10 CFR...

10 CFR Appendix A to Part 52 - Design Certification Rule for the U.S. Advanced Boiling Water Reactor

Code of Federal Regulations, 2011 CFR

2011-01-01

... Water Reactor A Appendix A to Part 52 Energy NUCLEAR REGULATORY COMMISSION (CONTINUED) LICENSES... Rule for the U.S. Advanced Boiling Water Reactor I. Introduction Appendix A constitutes the standard design certification for the U.S. Advanced Boiling Water Reactor (ABWR) design, in accordance with 10 CFR...

4. RW Meyer Sugar Mill: 18761889. Furnace doer for sugar ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

4. RW Meyer Sugar Mill: 1876-1889. Furnace doer for sugar boiling range. Manufactured by Honolulu Iron Works, Honolulu, 1879. Cost: $15.30. View: the furnace for the sugar boiling range was stoked from outside of the east wall of the boiling house. - R. W. Meyer Sugar Mill, State Route 47, Kualapuu, Maui County, HI

76 FR 70331 - List of Approved Spent Fuel Storage Casks: MAGNASTOR ® System, Revision 2

Federal Register 2010, 2011, 2012, 2013, 2014

2011-11-14

... various boron-10 areal densities for use with Pressurized Water Reactor and Boiling Water Reactor baskets... add various boron-10 areal densities for use with Pressurized Water Reactor and Boiling Water Reactor....1.1 to add various boron-10 areal densities for use with Pressurized Water Reactor and Boiling Water...

Mad Kids: How To Help Your Child Manage Anger.

ERIC Educational Resources Information Center

Beekman, Susan; Holmes, Jeanne

2002-01-01

Children move through the same anger cycle as adults and need similar coping strategies and problem solving skills. This paper presents pre-anger approaches, discussing what to do before the "boil-over" occurs, when the boiling point is reached, and after the boil-over. A sidebar presents a list of questions and activities parents can use with…

Cooking under Pressure: Applying the Ideal Gas Law in the Kitchen

ERIC Educational Resources Information Center

Chen, Ling; Anderson, Jennifer Y.; Wang, Diane R.

2010-01-01

This case study uses a daily cooking scenario to demonstrate how the boiling point of water is directly related to the external pressures in order to reinforce the concepts of boiling and boiling point, apply ideal gas law, and relate chemical reaction rates with temperatures. It also extends its teaching to autoclaves used to destroy…

Development of heat transfer enhancement techniques for external cooling of an advanced reactor vessel

NASA Astrophysics Data System (ADS)

Yang, Jun

Nucleate boiling is a well-recognized means for passively removing high heat loads (up to ˜106 W/m2) generated by a molten reactor core under severe accident conditions while maintaining relatively low reactor vessel temperature (<800 °C). With the upgrade and development of advanced power reactors, however, enhancing the nucleate boiling rate and its upper limit, Critical Heat Flux (CHF), becomes the key to the success of external passive cooling of reactor vessel undergoing core disrupture accidents. In the present study, two boiling heat transfer enhancement methods have been proposed, experimentally investigated and theoretically modelled. The first method involves the use of a suitable surface coating to enhance downward-facing boiling rate and CHF limit so as to substantially increase the possibility of reactor vessel surviving high thermal load attack. The second method involves the use of an enhanced vessel/insulation design to facilitate the process of steam venting through the annular channel formed between the reactor vessel and the insulation structure, which in turn would further enhance both the boiling rate and CHF limit. Among the various available surface coating techniques, metallic micro-porous layer surface coating has been identified as an appropriate coating material for use in External Reactor Vessel Cooling (ERVC) based on the overall consideration of enhanced performance, durability, the ease of manufacturing and application. Since no previous research work had explored the feasibility of applying such a metallic micro-porous layer surface coating on a large, downward facing and curved surface such as the bottom head of a reactor vessel, a series of characterization tests and experiments were performed in the present study to determine a suitable coating material composition and application method. Using the optimized metallic micro-porous surface coatings, quenching and steady-state boiling experiments were conducted in the Sub-scale Boundary Layer Boiling (SBLB) test facility at Penn State to investigate the nucleate boiling and CHF enhancement effects of the surface coatings by comparing the measurements with those for a plain vessel without coatings. An overall enhancement in nucleate boiling rates and CHF limits up to 100% were observed. Moreover, combination of data from quenching experiments and steady-state experiments produced new sets of boiling curves, which covered both the nucleate and transient boiling regimes with much greater accuracy. Beside the experimental work, a theoretical CHF model has also been developed by considering the vapor dynamics and the boiling-induced two-phase motions in three separate regions adjacent to the heating surface. The CHF model is capable of predicting the performance of micro-porous coatings with given particle diameter, porosity, media permeability and thickness. It is found that the present CHF model agrees favorably with the experimental data. Effects of an enhanced vessel/insulation structure on the local nucleate boiling rate and CHF limit have also been investigated experimentally. It is observed that the local two-phase flow quantities such as the local void fraction, quality, mean vapor velocity, mean liquid velocity, and mean vapor and liquid mass flow rates could have great impact on the local surface heat flux as boiling of water takes place on the vessel surface. An upward co-current two-phase flow model has been developed to predict the local two-phase flow behavior for different flow channel geometries, which are set by the design of insulation structures. It is found from the two-phase flow visualization experiments and the two-phase flow model calculations that the enhanced vessel/insulation structure greatly improved the steam venting process at the minimum gap location compared to the performance of thermal insulation structures without enhancement. Moveover, depending on the angular location, steady-state boiling experiments with the enhanced insulation design showed an enhancement of 1.8 to 3.0 times in the local critical heat flux. Finally, nucleate boiling and CHF correlations were developed based on the data obtained from various quenching and steady-state boiling experiments. Additionally, CHF enhancement factors were determined and examined to show the separate and integral effects of the two ERVC enhancement methods. When both vessel coating and insulation structure were used simultaneously, the integral effect on CHF enhancement was found much less than the product of the two separate effects, indicating possible competing mechanisms (i.e., interference) between the two enhancement methods.

An Experimental Study of Boiling in Reduced and Zero Gravity Fields

NASA Technical Reports Server (NTRS)

Usiskin, C. M.; Siegel, R.

1961-01-01

A pool boiling apparatus was mounted on a counterweighted platform which could be dropped a distance of nine feet. By varying the size of the counterweight, the effective gravity field on the equipment was adjusted between zero and unity. A study of boiling burnout in water indicated that a variation in the critical heat flux according to the one quarter power of gravity was reasonable. A consideration of the transient burnout process was necessary in order to properly interpret the data. A photographic study of nucleate boiling showed how the velocity of freely rising vapor bubbles decreased as gravity was reduced. The bubble diameters at the time of breakoff from the heated surface were found to vary inversely as gravity to the 1/3.5 power. Motion pictures were taken to illustrate both nucleate and film boiling in the low gravity range.

Boiling point measurement of a small amount of brake fluid by thermocouple and its application.

PubMed

Mogami, Kazunari

2002-09-01

This study describes a new method for measuring the boiling point of a small amount of brake fluid using a thermocouple and a pear shaped flask. The boiling point of brake fluid was directly measured with an accuracy that was within approximately 3 C of that determined by the Japanese Industrial Standards method, even though the sample volume was only a few milliliters. The method was applied to measure the boiling points of brake fluid samples from automobiles. It was clear that the boiling points of brake fluid from some automobiles dropped to approximately 140 C from about 230 C, and that one of the samples from the wheel cylinder was approximately 45 C lower than brake fluid from the reserve tank. It is essential to take samples from the wheel cylinder, as this is most easily subjected to heating.

Quantification of meat proportions by measuring DNA contents in raw and boiled sausages using matrix-adapted calibrators and multiplex real-time PCR.

PubMed

Köppel, René; Eugster, Albert; Ruf, Jürg; Rentsch, Jürg

2012-01-01

The quantification of meat proportions in raw and boiled sausage according to the recipe was evaluated using three different calibrators. To measure the DNA contents from beef, pork, sheep (mutton), and horse, a tetraplex real-time PCR method was applied. Nineteen laboratories analyzed four meat products each made of different proportions of beef, pork, sheep, and horse meat. Three kinds of calibrators were used: raw and boiled sausages of known proportions ranging from 1 to 55% of meat, and a dilution series of DNA from muscle tissue. In general, results generated using calibration sausages were more accurate than those resulting from the use of DNA from muscle tissue, and exhibited smaller measurement uncertainties. Although differences between uses of raw and boiled calibration sausages were small, the most precise and accurate results were obtained by calibration with fine-textured boiled reference sausages.

Effects of different cooking methods on health-promoting compounds of broccoli*

PubMed Central

Yuan, Gao-feng; Sun, Bo; Yuan, Jing; Wang, Qiao-mei

2009-01-01

The effects of five domestic cooking methods, including steaming, microwaving, boiling, stir-frying, and stir-frying followed by boiling (stir-frying/boiling), on the nutrients and health-promoting compounds of broccoli were investigated. The results show that all cooking treatments, except steaming, caused significant losses of chlorophyll and vitamin C and significant decreases of total soluble proteins and soluble sugars. Total aliphatic and indole glucosinolates were significantly modified by all cooking treatments but not by steaming. In general, the steaming led to the lowest loss of total glucosinolates, while stir-frying and stir-frying/boiling presented the highest loss. Stir-frying and stir-frying/boiling, the two most popular methods for most homemade dishes in China, cause great losses of chlorophyll, soluble protein, soluble sugar, vitamin C, and glucosinolates, but the steaming method appears the best in retention of the nutrients in cooking broccoli. PMID:19650196

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

Conceptual design for spacelab pool boiling experiment

NASA Technical Reports Server (NTRS)

Lienhard, J. H.; Peck, R. E.

1978-01-01

A pool boiling heat transfer experiment to be incorporated with a larger two-phase flow experiment on Spacelab was designed to confirm (or alter) the results of earth-normal gravity experiments which indicate that the hydrodynamic peak and minimum pool boiling heat fluxes vanish at very low gravity. Twelve small sealed test cells containing water, methanol or Freon 113 and cylindrical heaters of various sizes are to be built. Each cell will be subjected to one or more 45 sec tests in which the surface heat flux on the heaters is increased linearly until the surface temperature reaches a limiting value of 500 C. The entire boiling process will be photographed in slow-motion. Boiling curves will be constructed from thermocouple and electric input data, for comparison with the motion picture records. The conduct of the experiment will require no more than a few hours of operator time.

Turning bubbles on and off during boiling using charged surfactants

PubMed Central

Cho, H. Jeremy; Mizerak, Jordan P.; Wang, Evelyn N.

2015-01-01

Boiling—a process that has powered industries since the steam age—is governed by bubble formation. State-of-the-art boiling surfaces often increase bubble nucleation via roughness and/or wettability modification to increase performance. However, without active in situ control of bubbles, temperature or steam generation cannot be adjusted for a given heat input. Here we report the ability to turn bubbles ‘on and off' independent of heat input during boiling both temporally and spatially via molecular manipulation of the boiling surface. As a result, we can rapidly and reversibly alter heat transfer performance up to an order of magnitude. Our experiments show that this active control is achieved by electrostatically adsorbing and desorbing charged surfactants to alter the wettability of the surface, thereby affecting nucleation. This approach can improve performance and flexibility in existing boiling technologies as well as enable emerging or unprecedented energy applications. PMID:26486275

Forced convection flow boiling and two-phase flow phenomena in a microchannel

NASA Astrophysics Data System (ADS)

Na, Yun Whan

2008-07-01

The present study was performed to numerically analyze the evaporation phenomena through the liquid-vapor interface and to investigate bubble dynamics and heat transfer behavior during forced convective flow boiling in a microchannel. Flow instabilities of two-phase flow boiling in a microchannel were studied as well. The main objective of this research is to investigate the fundamental mechanisms of two-phase flow boiling in a microchannel and provide predictive tools to design thermal management systems, for example, microchannel heat sinks. The numerical results obtained from this study were qualitatively and quantitatively compared with experimental results in the open literature. Physical and mathematical models, accounting for evaporating phenomena through the liquid-vapor interface in a microchannel at constant heat flux and constant wall temperature, have been developed, respectively. The heat transfer mechanism is affected by the dominant heat conduction through the thin liquid film and vaporization at the liquid-vapor interface. The thickness of the liquid film and the pressure of the liquid and vapor phases were simultaneously solved by the governing differential equations. The developed semi-analytical evaporation model that takes into account of the interfacial phenomena and surface tension effects was used to obtain solutions numerically using the fourth-order Runge-Kutta method. The effects of heat flux 19 and wall temperature on the liquid film were evaluated. The obtained pressure drops in a microchannel were qualitatively consistent with the experimental results of Qu and Mudawar (2004). Forced convective flow boiling in a single microchannel with different channel heights was studied through a numerical simulation to investigate bubble dynamics, flow patterns, and heat transfer. The momentum and energy equations were solved using the finite volume method while the liquid-vapor interface of a bubble is captured using the VOF (Volume of Fluid) technique. The effects of different constant heat fluxes and different channel heights on the boiling mechanisms were investigated. The effects of liquid velocity on the bubble departure diameter were analyzed. The obtained results showed that the wall superheats at the position of nucleate boiling are relatively independent of the mass flow rates at the same channel height. The obtained results, however, showed that the heat flux at the onset of nucleate boiling strongly depends on the channel height. With a decrease of the channel height and an increase of the liquid velocity at the channel inlet, the departure diameter of a bubble was smaller. The periodic flow patterns, such as the bubbly flow, elongated slug flow, and churn flow were observed in the microchannel. Flow instabilities of two-phase flow boiling in a trapezoidal microchannel using a three-dimensional model were investigated. Fluctuation behaviors of flow boiling parameters such as wall temperature and inlet pressure caused by periodic flow patterns were studied at different heat fluxes and mass fluxes. The numerical results showed large amplitude and short period oscillations for wall temperature and inlet pressure fluctuations. Stable and unstable flow boiling regime with short period oscillations were investigated. Those flow boiling regimes were not listed in stable and unstable boiling regime map proposed by Wang et al. (2007).

The Gibbs Energy Basis and Construction of Boiling Point Diagrams in Binary Systems

ERIC Educational Resources Information Center

Smith, Norman O.

2004-01-01

An illustration of how excess Gibbs energies of the components in binary systems can be used to construct boiling point diagrams is given. The underlying causes of the various types of behavior of the systems in terms of intermolecular forces and the method of calculating the coexisting liquid and vapor compositions in boiling point diagrams with…

Production of High Density Aviation Fuels via Novel Zeolite Catalyst Routes

DTIC Science & Technology

1989-10-23

range fraction of a naphthenic crude; saturation of an aromatic FCC cycle stock I the appropriate boiling range: saturation of an appropriate boiling...aromatic hydrocarbons and selected aromatic feedstocks to the corresponding mono- and dicyclic naphthenes in the aviation turbine fuel boiling range; and...Paraffins from Naphthenic Refinery Feed Streams .......... 8 Solvent Extraction ........................................... 8 Shape Selective Catalytic

Exploring the Role of a Discrepant Event in Changing the Conceptions of Evaporation and Boiling in Elementary School Students

ERIC Educational Resources Information Center

Paik, Seoung-Hey

2015-01-01

The purpose of this study was to explore how examples used in teaching may influence elementary school students' conceptions of evaporation and boiling. To this end, the examples traditionally used to explain evaporation and boiling in Korean 4th grade science textbooks were analyzed. The functions of these published examples were explanation…

QSPR using MOLGEN-QSPR: the challenge of fluoroalkane boiling points.

PubMed

Rücker, Christoph; Meringer, Markus; Kerber, Adalbert

2005-01-01

By means of the new software MOLGEN-QSPR, a multilinear regression model for the boiling points of lower fluoroalkanes is established. The model is based exclusively on simple descriptors derived directly from molecular structure and nevertheless describes a broader set of data more precisely than previous attempts that used either more demanding (quantum chemical) descriptors or more demanding (nonlinear) statistical methods such as neural networks. The model's internal consistency was confirmed by leave-one-out cross-validation. The model was used to predict all unknown boiling points of fluorobutanes, and the quality of predictions was estimated by means of comparison with boiling point predictions for fluoropentanes.

Issue a Boil-Water Advisory or Wait for Definitive Information? A Decision Analysis

PubMed Central

Wagner, Michael M.; Wallstrom, Garrick L.; Onisko, Agnieszka

2005-01-01

Objective Study the decision to issue a boil-water advisory in response to a spike in sales of diarrhea remedies or wait 72 hours for the results of definitive testing of water and people. Methods Decision analysis. Results In the base-case analysis, the optimal decision is test-and-wait. If the cost of issuing a boil-water advisory is less than 13.92 cents per person per day, the optimal decision is to issue the boil-water advisory immediately. Conclusions Decisions based on surveillance data that are suggestive but not conclusive about the existence of a disease outbreak can be modeled. PMID:16779145

Enhancements of Nucleate Boiling Under Microgravity Conditions

NASA Technical Reports Server (NTRS)

Zhang, Nengli; Chao, David F.; Yang, W. J.

2000-01-01

This paper presents two means for enhancing nucleate boiling and critical heat flux under microgravity conditions: using micro-configured metal-graphite composites as the boiling surface and dilute aqueous solutions of long-chain alcohols as the working fluid. In the former, thermocapillary force induced by temperature difference between the graphite-fiber tips and the metal matrix plays an important role in bubble detachment. Thus boiling-heat transfer performance does not deteriorate in a reduced-gravity environment. In the latter cases, the surface tension-temperature gradient of the long-chain alcohol solutions turns positive as the temperature exceeds a certain value. Consequently, the Marangoni effect does not impede, but rather aids in bubble departure from the heating surface. This feature is most favorable in microgravity. As a result, the bubble size of departure is substantially reduced at higher frequencies. Based on the existing experimental data, and a two-tier theoretical model, correlation formulas are derived for nucleate boiling on the copper-graphite and aluminum-graphite composite surfaces, in both the isolated and coalesced bubble regimes. In addition, performance equations for nucleate boiling and critical heat flux in dilute aqueous solutions of long-chain alcohols are obtained.

Estimation of boiling points using density functional theory with polarized continuum model solvent corrections.

PubMed

Chan, Poh Yin; Tong, Chi Ming; Durrant, Marcus C

2011-09-01

An empirical method for estimation of the boiling points of organic molecules based on density functional theory (DFT) calculations with polarized continuum model (PCM) solvent corrections has been developed. The boiling points are calculated as the sum of three contributions. The first term is calculated directly from the structural formula of the molecule, and is related to its effective surface area. The second is a measure of the electronic interactions between molecules, based on the DFT-PCM solvation energy, and the third is employed only for planar aromatic molecules. The method is applicable to a very diverse range of organic molecules, with normal boiling points in the range of -50 to 500 °C, and includes ten different elements (C, H, Br, Cl, F, N, O, P, S and Si). Plots of observed versus calculated boiling points gave R²=0.980 for a training set of 317 molecules, and R²=0.979 for a test set of 74 molecules. The role of intramolecular hydrogen bonding in lowering the boiling points of certain molecules is quantitatively discussed. Crown Copyright © 2011. Published by Elsevier Inc. All rights reserved.

Noise analysis of nucleate boiling

NASA Technical Reports Server (NTRS)

Mcknight, R. D.; Ram, K. S.

1971-01-01

The techniques of noise analysis have been utilized to investigate nucleate pool boiling. A simple experimental setup has been developed for obtaining the power spectrum of a nucleate boiling system. These techniques were first used to study single bubbles, and a method of relating the two-dimensional projected size and the local velocity of the bubbles to the auto-correlation functions is presented. This method is much less time consuming than conventional methods of measurement and has no probes to disturb the system. These techniques can be used to determine the contribution of evaporation to total heat flux in nucleate boiling. Also, these techniques can be used to investigate the effect of various parameters upon the frequency response of nucleate boiling. The predominant frequencies of the power spectrum correspond to the frequencies of bubble generation. The effects of heat input, degree of subcooling, and liquid surface tension upon the power spectra of a boiling system are presented. It was found that the degree of subcooling has a more pronounced effect upon bubble size than does heat flux. Also the effect of lowering surface tension can be sufficient to reduce the effect of the degree of subcooling upon the size of the bubbles.

Gravity and Heater Size Effects on Pool Boiling Heat Transfer

NASA Technical Reports Server (NTRS)

Kim, Jungho; Raj, Rishi

2014-01-01

The current work is based on observations of boiling heat transfer over a continuous range of gravity levels between 0g to 1.8g and varying heater sizes with a fluorinert as the test liquid (FC-72/n-perfluorohexane). Variable gravity pool boiling heat transfer measurements over a wide range of gravity levels were made during parabolic flight campaigns as well as onboard the International Space Station. For large heaters and-or higher gravity conditions, buoyancy dominated boiling and heat transfer results were heater size independent. The power law coefficient for gravity in the heat transfer equation was found to be a function of wall temperature under these conditions. Under low gravity conditions and-or for smaller heaters, surface tension forces dominated and heat transfer results were heater size dependent. A pool boiling regime map differentiating buoyancy and surface tension dominated regimes was developed along with a unified framework that allowed for scaling of pool boiling over a wide range of gravity levels and heater sizes. The scaling laws developed in this study are expected to allow performance quantification of phase change based technologies under variable gravity environments eventually leading to their implementation in space based applications.

Effect of Different Cooking Methods on Histamine Levels in Selected Foods

PubMed Central

Chung, Bo Young; Park, Sook Young; Byun, Yun Sun; Son, Jee Hee; Choi, Yong Won; Cho, Yong Se

2017-01-01

Background Histamine in food is known to cause food poisoning and allergic reactions. We usually ingest histamine in cooked food, but there are few studies about the influence of cooking method on the histamine level. Objective The purpose of this study was to determine the influence of cooking methods on the concentration of histamine in foods. Methods The foods chosen were those kinds consumed frequently and cooked by grilling, boiling, and frying. The histamine level of the food was measured using enzyme-linked immunosorbent assay. Results Grilled seafood had higher histamine levels than raw or boiled seafood. For meat, grilling increased the histamine level, whereas boiling decreased it. For eggs, there was not much difference in histamine level according to cooking method. Fried vegetables had higher histamine levels than raw vegetables. And fermented foods didn't show much difference in histamine level after being boiled. Conclusion The histamine level in food has changed according to the cooking method used to prepare it. Frying and grilling increased histamine level in foods, whereas boiling had little influence or even decreased it. The boiling method might be helpful to control the effect of histamine in histamine-sensitive or susceptible patients, compared with frying and grilling. PMID:29200758

Flow Boiling and Condensation Experiment (FBCE) for the International Space Station

NASA Technical Reports Server (NTRS)

Mudawar, Issam; O'Neill, Lucas; Hasan, Mohammad; Nahra, Henry; Hall, Nancy; Balasubramaniam, R.; Mackey, Jeffrey

2016-01-01

An effective means to reducing the size and weight of future space vehicles is to replace present mostly single-phase thermal management systems with two-phase counterparts. By capitalizing upon both latent and sensible heat of the coolant rather than sensible heat alone, two-phase thermal management systems can yield orders of magnitude enhancement in flow boiling and condensation heat transfer coefficients. Because the understanding of the influence of microgravity on two-phase flow and heat transfer is quite limited, there is an urgent need for a new experimental microgravity facility to enable investigators to perform long-duration flow boiling and condensation experiments in pursuit of reliable databases, correlations and models. This presentation will discuss recent progress in the development of the Flow Boiling and Condensation Experiment (FBCE) for the International Space Station (ISS) in collaboration between Purdue University and NASA Glenn Research Center. Emphasis will be placed on the design of the flow boiling module and on new flow boiling data that were measured in parabolic flight, along with extensive flow visualization of interfacial features at heat fluxes up to critical heat flux (CHF). Also discussed a theoretical model that will be shown to predict CHF with high accuracy.

Large-scale boiling experiments of the flooded cavity concept for in-vessel core retention

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

Chu, T.Y.; Slezak, S.E.; Bentz, J.H.

1994-03-01

This paper presents results of ex-vessel boiling experiments performed in the CYBL (CYlindrical BoiLing) facility. CYBL is a reactor-scale facility for confirmatory research of the flooded cavity concept for accident management. CYBL has a tank-within-a-tank design; the inner tank simulates the reactor vessel and the outer tank simulates the reactor cavity. Experiments with uniform and edge-peaked heat flux distributions up to 20 W/cm{sup 2} across the vessel bottom were performed. Boiling outside the reactor vessel was found to be subcooled nucleate boiling. The subcooling is mainly due to the gravity head which results from flooding the sides of the reactormore » vessel. The boiling process exhibits a cyclic pattern with four distinct phases: direct liquid/solid contact, bubble nucleation and growth, coalescence, and vapor mass dispersion (ejection). The results suggest that under prototypic heat load and heat flux distributions, the flooded cavity in a passive pressurized water reactor like the AP-600 should be capable of cooling the reactor pressure vessel in the central region of the lower head that is addressed by these tests.« less

Overnight soaking or boiling of "Matooke" to reduce potassium content for patients with chronic kidney disease: does it really work?

PubMed

Asiimwe, J; Sembajwe, L F; Senoga, A; Bakiika, E; Muwonge, H; Kalyesubula, R

2013-09-01

There is an increase in number of patients with chronic kidney disease (CKD) in Uganda's health facilities looking for different options of preparing matooke (bananas), their staple food. To establish and evaluate an effective method of removing potassium from bananas (matooke). Bananas were sampled from 5 markets in Kampala, Uganda. Deionized water was used to soak the bananas and the potassium concentration was determined using an atomic absorption spectrophotometer in both the bananas and water after soaking for varying time intervals. We also determined the potassium concentrations in the bananas and the water after boiling the bananas at 200 degrees Celsius at intervals of 10 minutes (for 60 minutes). The potassium concentration did not appear to change on soaking alone without boiling. However, on boiling, the concentration in the bananas decreased from about 1.4 ppm to approx. 1 ppm after 60 min; yet the concentration of potassium released into deionized water increased steadily from 0.0 ppm to about 1.2 ppm after 60 min of boiling. This study demonstrates that boiling the bananas is a more effective way of removing the potassium from bananas than simply soaking them.

A genetic algorithm-based optimization model for pool boiling heat transfer on horizontal rod heaters at isolated bubble regime

NASA Astrophysics Data System (ADS)

Alavi Fazel, S. Ali

2017-09-01

A new optimized model which can predict the heat transfer in the nucleate boiling at isolated bubble regime is proposed for pool boiling on a horizontal rod heater. This model is developed based on the results of direct observations of the physical boiling phenomena. Boiling heat flux, wall temperature, bubble departing diameter, bubble generation frequency and bubble nucleation site density have been experimentally measured. Water and ethanol have been used as two different boiling fluids. Heating surface was made by several metals and various degrees of roughness. The mentioned model considers various mechanisms such as latent heat transfer due to micro-layer evaporation, transient conduction due to thermal boundary layer reformation, natural convection, heat transfer due to the sliding bubbles and bubble super-heating. The fractional contributions of individual mentioned heat transfer mechanisms have been calculated by genetic algorithm. The results show that at wall temperature difference more that about 3 K, bubble sliding transient conduction, non-sliding transient conduction, micro-layer evaporation, natural convection, radial forced convection and bubble super-heating have higher to lower fractional contributions respectively. The performance of the new optimized model has been verified by comparison of the existing experimental data.

Characterization of Single Phase and Two Phase Heat and Momentum Transport in a Spiraling Radial Inow Microchannel Heat Sink

NASA Astrophysics Data System (ADS)

Ruiz, Maritza

Thermal management of systems under high heat fluxes on the order of hundreds of W/cm2 is important for the safety, performance and lifetime of devices, with innovative cooling technologies leading to improved performance of electronics or concentrating solar photovoltaics. A novel, spiraling radial inflow microchannel heat sink for high flux cooling applications, using a single phase or vaporizing coolant, has demonstrated enhanced heat transfer capabilities. The design of the heat sink provides an inward swirl flow between parallel, coaxial disks that form a microchannel of 1 cm radius and 300 micron channel height with a single inlet and a single outlet. The channel is heated on one side through a conducting copper surface, and is essentially adiabatic on the opposite side to simulate a heat sink scenario for electronics or concentrated photovoltaics cooling. Experimental results on the heat transfer and pressure drop characteristics in the heat sink, using single phase water as a working fluid, revealed heat transfer enhancements due to flow acceleration and induced secondary flows when compared to unidirectional laminar fully developed flow between parallel plates. Additionally, thermal gradients on the surface are small relative to the bulk fluid temperature gain, a beneficial feature for high heat flux cooling applications. Heat flux levels of 113 W/cm2 at a surface temperature of 77 deg C were reached with a ratio of pumping power to heat rate of 0.03%. Analytical models on single phase flow are used to explore the parametric trends of the flow rate and passage geometry on the streamlines and pressure drop through the device. Flow boiling heat transfer and pressure drop characteristics were obtained for this heat sink using water at near atmospheric pressure as the working fluid for inlet subcooling levels ranging from 20 to 80 deg C and mean mass flux levels ranging from 184-716 kg/m. 2s. Flow enhancements similar to singlephase flow were expected, as well as enhancements due to increased buoyant forces on vapor bubbles resulting from centripetal acceleration in the flow which will tend to draw the vapor towards the outlet. This can also aid in the reduction of vapor obstruction of the flow. The flow was identified as transitioning through three regimes as the heat rate was increased: partial subcooled flow boiling, oscillating boiling and fully developed flow boiling. During partial subcooled flow boiling, both forced convective and nucleate boiling effects are important. During oscillating boiling, the system fluctuated between partial subcooled flow boiling and fully developed nucleate boiling. Temperature and pressure oscillations were significant in this regime and are likely due to bubble constriction of flow in the microchannel. This regime of boiling is generally undesirable due to the large oscillations in temperatures and pressure and design constraints should be established to avoid large oscillations from occurring. During fully developed flow boiling, water vapor rapidly leaves the surface and the flow does not sustain large oscillations. Reducing inlet subcooling levels was found to reduce the magnitude of oscillations in the oscillating boiling regime. Additionally, reduced inlet subcooling levels reduced the average surface temperature at the highest heat flux levels tested when heat transfer was dominated by nucleate boiling, yet increased the average surface temperatures at low heat flux levels when heat transfer was dominated by forced convection. Experiments demonstrated heat fluxes up to 301 W/cm. 2at an average surface temperature of 134 deg C under partial subcooled flow boiling conditions. At this peak heat flux, the system required a pumping power to heat rate ratio of 0.01%. This heat flux is 2.4 times the typical values for critical heat flux in pool boiling under similar conditions.

A Twice Electrochemical-Etching Method to Fabricate Superhydrophobic-Superhydrophilic Patterns for Biomimetic Fog Harvest.

PubMed

Yang, Xiaolong; Song, Jinlong; Liu, Junkai; Liu, Xin; Jin, Zhuji

2017-08-18

Superhydrophobic-superhydrophilic patterned surfaces have attracted more and more attention due to their great potential applications in the fog harvest process. In this work, we developed a simple and universal electrochemical-etching method to fabricate the superhydrophobic-superhydrophilic patterned surface on metal superhydrophobic substrates. The anti-electrochemical corrosion property of superhydrophobic substrates and the dependence of electrochemical etching potential on the wettability of the fabricated dimples were investigated on Al samples. Results showed that high etching potential was beneficial for efficiently producing a uniform superhydrophilic dimple. Fabrication of long-term superhydrophilic dimples on the Al superhydrophobic substrate was achieved by combining the masked electrochemical etching and boiling-water immersion methods. A long-term wedge-shaped superhydrophilic dimple array was fabricated on a superhydrophobic surface. The fog harvest test showed that the surface with a wedge-shaped pattern array had high water collection efficiency. Condensing water on the pattern was easy to converge and depart due to the internal Laplace pressure gradient of the liquid and the contact angle hysteresis contrast on the surface. The Furmidge equation was applied to explain the droplet departing mechanism and to control the departing volume. The fabrication technique and research of the fog harvest process may guide the design of new water collection devices.

Odd-Boiled Eggs

ERIC Educational Resources Information Center

Kaminsky, Kenneth; Scheman, Naomi

2010-01-01

At a Shabbat lunch in Madrid not long ago, the conversation turned to the question of boiling eggs. One of the guests mentioned that a Dutch rabbi he knew had heard that in order to make it more likely that boiled eggs be kosher, you should add an egg to the pot if the number you began with was even. According to the laws of Kashruth, Jews may not…

The Influence of a Lower Heated Tube on Nucleate Pool Boiling from a Horizontal Tube

DTIC Science & Technology

1992-06-01

9 C. CONDENSER SECTION .................................... 12 D. COOLING SECTION...lower tube kc thermal conductivity of copper L active boiling tube length Lu non-boiling tube length x Nu Nusselt number p tube outside wall perimeter Pr...teflon endplates. 2. A condenser , assembled using a similar Pyrex-glass tee with aluminum endplates. 3. A reservoir for R- 114 liquid storage. 4. A

18. RW Meyer Sugar Mill: 18761889. Boiling House Interior, 1878. ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

18. RW Meyer Sugar Mill: 1876-1889. Boiling House Interior, 1878. View: Detail of floor with molasses pits below floor level. The remaining floor boards indicate the structure of the floor covering the entire inside of the boiling house. In the left background the base of the centrifugals are in view. - R. W. Meyer Sugar Mill, State Route 47, Kualapuu, Maui County, HI

Heat Transfer in Boiling Dilute Emulsion with Strong Buoyancy

NASA Astrophysics Data System (ADS)

Freeburg, Eric Thomas

Little attention has been given to the boiling of emulsions compared to that of boiling in pure liquids. The advantages of using emulsions as a heat transfer agent were first discovered in the 1970s and several interesting features have since been studied by few researchers. Early research focuses primarily on pool and flow boiling and looks to determine a mechanism by which the boiling process occurs. This thesis looks at the boiling of dilute emulsions in fluids with strong buoyant forces. The boiling of dilute emulsions presents many favorable characteristics that make it an ideal agent for heat transfer. High heat flux electronics, such as those seen in avionics equipment, produce high heat fluxes of 100 W/cm2 or more, but must be maintained at low temperatures. So far, research on single phase convection and flow boiling in small diameter channels have yet to provide an adequate solution. Emulsions allow the engineer to tailor the solution to the specific problem. The fluid can be customized to retain the high thermal conductivity and specific heat capacity of the continuous phase while enhancing the heat transfer coefficient through boiling of the dispersed phase component. Heat transfer experiments were carried out with FC-72 in water emulsions. FC-72 has a saturation temperature of 56 °C, far below that of water. The parameters were varied as follows: 0% ≤ epsilon ≤ 1% and 1.82 x 1012 ≤ RaH ≤ 4.42 x 1012. Surface temperatures along the heated surface reached temperature that were 20 °C in excess of the dispersed phase saturation temperature. An increase of ˜20% was seen in the average Nusselt numbers at the highest Rayleigh numbers. Holography was used to obtain images of individual and multiple FC-72 droplets in the boundary layer next to the heated surface. The droplet diameters ranged from 0.5 mm to 1.3 mm. The Magnus effect was observed when larger individual droplets were injected into the boundary layer, causing the droplets to be pushed outside the boundary layer. Vaporization of FC-72 droplets in the boundary layer next to the heated surface was not observed.

Ovomucoid (Gal d 1) specific IgE detected by microarray system predict tolerability to boiled hen's egg and an increased risk to progress to multiple environmental allergen sensitisation.

PubMed

Alessandri, C; Zennaro, D; Scala, E; Ferrara, R; Bernardi, M Livia; Santoro, M; Palazzo, P; Mari, A

2012-03-01

Egg allergy is a very common finding in early childhood. Detecting hen's egg (HE) allergy outgrowing and reintroduction of food containing egg is a task for the allergist. We sought to evaluate the suitability of boiled egg food challenge compared with IgE to allergenic molecules from HE white using a microarray system. Sixty-eight children referring to our centre by the family paediatricians for a suspected egg allergy were enrolled. Patients underwent double-blind, placebo-controlled food challenge with boiled and raw eggs. Challenge outcomes were compared with skin tests performed using egg white and yolk commercial extracts, to prick-prick test with boiled and raw egg white and yolk, total IgE, egg white specific IgE detected using ImmunoCAP and IgE to egg allergens available on the immunosolid phase allergen chip (ISAC) 103 microarray. Nineteen subjects (28%) were reactive to both raw and boiled egg, 14 (20.5%) to raw egg only and 35 (51.4%) tolerated both boiled and raw egg. Efficiency analysis was carried out using both raw and boiled egg challenges as gold standard. Forty four of 47 Gal d 1 negative patients tolerated boiled egg (94%). Conversely, 20 of 21 Gal d 1 positive patients reacted to raw egg (95%). None of the other tests was able to discriminate patients' response to HE challenge. Furthermore, Gal d 1 positivity seems to lead to broader environmental allergen IgE sensitization. The Gal d 1 IgE reactivity appears to be a very good predictor of HE clinical allergy. Gal d 1 positive children have a high frequency of HE allergy, whereas Gal d 1 negative children have a high frequency of tolerance to boiled egg. Multiple specific IgE detection by means of ISAC improves the diagnostic approach in HE allergic children, disclosing other food and inhalant allergic sensitizations, anyhow requiring a comprehensive clinical evaluation. © 2011 Blackwell Publishing Ltd.

On-chip dual-comb based on quantum cascade laser frequency combs

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

Villares, G., E-mail: gustavo.villares@phys.ethz.ch; Wolf, J.; Kazakov, D.

2015-12-21

Dual-comb spectroscopy is emerging as an appealing application of mid-infrared frequency combs for high-resolution molecular spectroscopy, as it leverages on the unique coherence properties of frequency combs. Here, we present an on-chip dual-comb source based on mid-infrared quantum cascade laser frequency combs. Control of the combs repetition and offset frequencies is obtained by integrating micro-heaters next to each laser. We show that a full control of the dual-comb system is possible, by measuring a multi-heterodyne beating corresponding to an optical bandwidth of 32 cm{sup −1} centered at 1330 cm{sup −1} (7.52 μm), demonstrating that this device represents a critical step towards compact dual-combmore » systems.« less

Boiling process modelling peculiarities analysis of the vacuum boiler

NASA Astrophysics Data System (ADS)

Slobodina, E. N.; Mikhailov, A. G.

2017-06-01

The analysis of the low and medium powered boiler equipment development was carried out, boiler units possible development directions with the purpose of energy efficiency improvement were identified. Engineering studies for the vacuum boilers applying are represented. Vacuum boiler heat-exchange processes where boiling water is the working body are considered. Heat-exchange intensification method under boiling at the maximum heat- transfer coefficient is examined. As a result of the conducted calculation studies, heat-transfer coefficients variation curves depending on the pressure, calculated through the analytical and numerical methodologies were obtained. The conclusion about the possibility of numerical computing method application through RPI ANSYS CFX for the boiling process description in boiler vacuum volume was given.

Quantitative structure-property relationships for prediction of boiling point, vapor pressure, and melting point.

PubMed

Dearden, John C

2003-08-01

Boiling point, vapor pressure, and melting point are important physicochemical properties in the modeling of the distribution and fate of chemicals in the environment. However, such data often are not available, and therefore must be estimated. Over the years, many attempts have been made to calculate boiling points, vapor pressures, and melting points by using quantitative structure-property relationships, and this review examines and discusses the work published in this area, and concentrates particularly on recent studies. A number of software programs are commercially available for the calculation of boiling point, vapor pressure, and melting point, and these have been tested for their predictive ability with a test set of 100 organic chemicals.

Estimating surface temperature in forced convection nucleate boiling - A simplified method

NASA Technical Reports Server (NTRS)

Hendricks, R. C.; Papell, S. S.

1977-01-01

A simplified expression to estimate surface temperatures in forced convection boiling was developed using a liquid nitrogen data base. Using the principal of corresponding states and the Kutateladze relation for maximum pool boiling heat flux, the expression was normalized for use with other fluids. The expression was applied also to neon and water. For the neon data base, the agreement was acceptable with the exclusion of one set suspected to be in the transition boiling regime. For the water data base at reduced pressure greater than 0.05 the agreement is generally good. At lower reduced pressures, the water data scatter and the calculated temperature becomes a function of flow rate.

3. RW Meyer Sugar Mill: 18761889. Sorghum pan and boiling ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

3. RW Meyer Sugar Mill: 1876-1889. Sorghum pan and boiling range flue. Manufactured by John Nott & Co., Honolulu, Hawaii, 1878. View: South side of sorghum pan and boiling range flue. In the sorghum pan heat was applied to the cane juice to clarify it, evaporate its water content, and concentrate the sugar crystals. Hot gasses moved through the flue underneath the entire copper bottom of the sorghum pan from the furnace (east) end to the smokestack (west) end of the boiling range. The sorghum pan sides are of redwood. The flue is built of fire-brick, masonry, and portland cement. - R. W. Meyer Sugar Mill, State Route 47, Kualapuu, Maui County, HI

Critical heat flux for free convection boiling in thin rectangular channels

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

Cheng, Lap Y.; Tichler, P.R.

A review of the experimental data on free convection boiling critical heat flux (CHF) in vertical rectangular channels reveals three mechanisms of burnout. They are the pool boiling limit, the circulation limit, and the flooding limit associated with a transition in flow regime from churn to annular flow. The dominance of a particular mechanism depends on the dimensions of the channel. Analytical models were developed for each free convection boiling limit. Limited agreement with data is observed. A CHF correlation, which is valid for a wide range of gap sizes, was constructed from the CHFs calculated according to the threemore » mechanisms of burnout. 17 refs., 7 figs.« less

The purity of water at hospital and at home as a problem of intercultural understanding.

PubMed

Burghart, R

1996-03-01

Women in a provincial town in southern Nepal were instructed by medical doctors and compounders to boil water, and to keep it boiling for 15 minutes before mixing it with infant formula or oral rehydration salts. Most women ignored the advice. Those who seemed to follow it merely brought the water to boil. This report describes how and why women boil water and assesses the health implications of their practices. The failure of women to adopt "proper" procedures procedures provides a point of entry into an analysis of the role of intercultural dialogue in exposing one's presuppositions about health and empowering one to change them.

BOILING HEAT TRANSFER IN ZERO GRAVITY

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

Zara, E.A.

1964-01-01

The preliminary results of a research program to determine the effects of zero and near zero gravity on boiling heat transfer are presented. Zero gravity conditions were obtained on the ASD KC-135 zero gravity test aircraft, capable of providing 30-seconds of zero gravity. Results of the program to date indicate that nucleate (bubble) boiling heat transfer rates are not greatly affected by the absence of gravity forces. However, radical pressure increases were observed that will dictate special design considerations to space vehicle systems utilizing pool boiling processes, such as cryogenic or other fluid storage vessels where thermal input to themore » fluid is used for vessel pressurization. (auth)« less

Passive microwave device applications of high T(c) superconducting thin films

NASA Astrophysics Data System (ADS)

Lyons, W. G.; Withers, R. S.

1990-11-01

Superconductors with a transition temperature T(c) from 40 K to 125 K are analyzed, with focus placed on their behavior around the boiling point of liquid nitrogen (77 K). It is shown that high-T(c) superconductors are similar to conventional type-II superconductors with paired holes instead of paired electrons. The nature of the electromagnetic response of a superconductor is illustrated with a two-fluid model, and surface resistance and conductor loss are assessed. Several microwave applications of high-T(c) superconductors are outlined including a six-pole dielectric loaded cavity filter used in multiplexers on current communication satellites and a four-pole superconducting filter. An implementation of a chirp filter using superconducting striplines with a cascaded array of backward-wave couplers to achieve a downchirp is presented as well as a 60-GHz phased antenna utilizing microstrip lines in the feed network.

Anti-Inflammatory Effects of Water Chestnut Extract on Cytokine Responses via Nuclear Factor-κB-signaling Pathway

PubMed Central

Kim, Bora; Kim, Jin Eun; Choi, Byung-Kook; Kim, Hyun-Soo

2015-01-01

Water chestnut (Trapa japonica Flerov.) is an annual aquatic plant. In the present study, we showed that the treatment of water chestnut extracted with boiling water resulted in a significant increase 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical-scavenging activity and decrease the intracellular H2O2-induced accumulation of reactive oxygen species. In addition, water chestnut extract (WCE) inhibited lipopolysaccharide (LPS)-induced nitric oxide production and suppressed mRNA and protein expression of the inducible nitric oxide synthase gene. The cytokine array results showed that WCE inhibited inflammatory cytokine secretion. Also, WCE reduced tumor necrosis factor-α-and interleukin-6-induced nuclear factor-αB activity. Furthermore, during sodium lauryl sulfate (SLS)-induced irritation of human skin, WCE reduced SLS-induced skin erythema and improved barrier regeneration. These results indicate that WCE may be a promising topical anti-inflammatory agent. PMID:25593649

Critical Heat Flux in Pool Boiling on Metal-Graphite Composite Surfaces

NASA Technical Reports Server (NTRS)

Zhang, Nengli; Yang, Wen-Jei; Chao, David F.; Chao, David F. (Technical Monitor)

2000-01-01

A study is conducted on high heat-flux pool boiling of pentane on micro-configured composite surfaces. The boiling surfaces are copper-graphite (Cu-Gr) and aluminum-graphite (Al-Gr) composites with a fiber volume concentration of 50%. The micro-graphite fibers embedded in the matrix contribute to a substantial enhancement in boiling heat-transfer performance. Correlation equations are obtained for both the isolated and coalesced bubble regimes, utilizing a mathematical model based on a metal-graphite, two-tier configuration with the aid of experimental data. A new model to predict the critical heat flux (CHF) on the composites is proposed to explain the fundamental aspects of the boiling phenomena. Three different factors affecting the CHF are considered in the model. Two of them are expected to become the main agents driving vapor volume detachment under microgravity conditions, using the metal-graphite composite surfaces as the heating surface and using liquids with an unusual Marangoni effect as the working fluid.

A study of forced convection boiling under reduced gravity

NASA Technical Reports Server (NTRS)

Merte, Herman, Jr.

1992-01-01

This report presents the results of activities conducted over the period 1/2/85-12/31/90, in which the study of forced convection boiling under reduced gravity was initiated. The study seeks to improve the understanding of the basic processes that constitute forced convection boiling by removing the buoyancy effects which may mask other phenomena. Specific objectives may also be expressed in terms of the following questions: (1) what effects, if any, will the removal of body forces to the lowest possible levels have on the forced convection boiling heat transfer processes in well-defined and meaningful circumstances? (this includes those effects and processes associated with the nucleation or onset of boiling during the transient increase in heater surface temperature, as well as the heat transfer and vapor bubble behaviors with established or steady-state conditions); and (2) if such effects are present, what are the boundaries of the relevant parameters such as heat flux, heater surface superheat, fluid velocity, bulk subcooling, and geometric/orientation relationships within which such effects will be produced?

Contamination of different portions of raw and boiled specimens of Norway lobster by mercury and selenium.

PubMed

Perugini, Monia; Visciano, Pierina; Manera, Maurizio; Abete, Maria Cesarina; Gavinelli, Stefania; Amorena, Michele

2013-11-01

The aim of this study was to evaluate mercury and selenium distribution in different portions (exoskeleton, white meat and brown meat) of Norway lobster (Nephrops norvegicus). Some samples were also analysed as whole specimens. The same portions were also examined after boiling, in order to observe if this cooking practice could affect mercury and selenium concentrations. The highest mercury concentrations were detected in white meat, exceeding in all cases the maximum levels established by European legislation. The brown meat reported the highest selenium concentrations. In all boiled samples, mercury levels showed a statistically significant increase compared to raw portions. On the contrary, selenium concentrations detected in boiled samples of white meat, brown meat and whole specimen showed a statistically significant decrease compared to the corresponding raw samples. These results indicate that boiling modifies mercury and selenium concentrations. The high mercury levels detected represent a possible risk for consumers, and the publication and diffusion of specific advisories concerning seafood consumption is recommended.

Studies on sodium boiling phenomena in out of pile rod bundles for various accidental situations in Liquid Metal Fast Breeder Reactors (LMFBR) experiments and interpretations

NASA Astrophysics Data System (ADS)

Seiler, J. M.; Rameau, B.

Bundle sodium boiling in nominal geometry for different accident conditions is reviewed. Voiding of a subassembly is controlled by not only hydrodynamic effects but mainly by thermal effects. There is a strong influence of the thermal inertia of the bundle material compared to the sodium thermal inertia. Flow instability, during a slow transient, can be analyzed with numerical tools and estimated using simplified approximations. Stable boiling operational conditions under bundle mixed convection (natural convection in the reactor) can be predicted. Voiding during a fast transient can be approximated from single channel calculations. The phenomenology of boiling behavior for a subassembly with inlet completely blocked, submitted to decay heat and lateral cooling; two-phase sodium flow pressure drop in a tube of large hydraulic diameter under adiabatic conditions; critical flow phenomena and voiding rate under high power, slow transient conditions; and onset of dry out under local boiling remains problematical.

Low gravity quenching of hot tubes with cryogens

NASA Technical Reports Server (NTRS)

Antar, Basil N.; Collins, Frank G.; Kawaji, M.

1992-01-01

An experimental proceedure for examining flow boiling in low gravity environment is presented. The proceedure involves both ground based and KC-135 flight experiments. Two experimental apparati were employed, one for studying subcooled liquid boiling and another for examining saturated liquid boiling. For the saturated flow experiments, liquid nitrogen was used while freon 113 was used for the subcooled flow experiments. The boiling phenomenon was investigated in both cases using flow visualization techniques as well as tube wall temperature measurements. The flow field in both cases was established by injecting cold liquid in a heated tube whose temperature was set above the saturation values. The tubes were both vertically and horizontally supported with the liquid injected from the lower end of the tube. The results indicate substantial differences in the flow patterns established during boiling between the ground based, (1-g), experiments and the flight experiments, (low-g). These differences in the flow patterns will be discussed and some explanations will be offered.

Carbuncle

MedlinePlus

Skin infection - staphylococcal; Infection - skin - staph; Staph skin infection; Carbunculosis; Boil ... aureus ). A carbuncle is a cluster of several skin boils ( furuncles ). The infected mass is filled with ...

Observations of the boiling process from a downward-facing torispherical surface: Confirmatory testing of the heavy water new production reactor flooded cavity design

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

Chu, T.Y.; Bentz, J.H.; Simpson, R.B.

1995-06-01

Reactor-scale ex-vessel boiling experiments were performed in the CYBL facility at Sandia National Laboratories. The boiling flow pattern outside the RPV bottom head shows a center pulsating region and an outer steady two-phase boundary layer region. The local heat transfer data can be correlated in terms of a modified Rohsenow correlation.

Hypocotyls of Lepidium meyenii (maca), a plant of the Peruvian highlands, prevent ultraviolet A-, B-, and C-induced skin damage in rats.

PubMed

Gonzales-Castañeda, Cynthia; Gonzales, Gustavo F

2008-02-01

Lepidium meyenii (maca) is a plant that grows exclusively in the Peruvian Central Andes, where ultraviolet radiation (UVR) is predominant. Determine if two extracts of maca can provide dermal protection against UVR. We have administered two maca extracts (0.13 mg/ml), one obtained after boiling and the other without boiling, on the dorsal surface of male Holtzman rats exposed to UVC radiation once a week during 3 consecutive weeks. A dose-response effect of an aqueous extract of maca after a boiling process under exposure of rats to UVA, UVB, or UVC was also studied. A commercial sunscreen was used as a positive control. UVR caused significant increase in skin epidermal thickness. The epidermal height in animals treated with maca was similar to those who did not receive UVR. The aqueous extract of maca after a boiling process had better effect than maca extract without a boiling process. A dose-response effect was observed with increasing doses of aqueous extract of maca after a boiling process. Maca extract had benzyl glucosinolates and polyphenols. Maca extracts protect the skin of rats against UV irradiations and can be suggested as an alternative means of solar protection.

Ultrasonic atomization of tissue and its role in tissue fractionation by high intensity focused ultrasound

PubMed Central

Simon, Julianna C.; Sapozhnikov, Oleg A.; Khokhlova, Vera A.; Wang, Yak-Nam; Crum, Lawrence A.; Bailey, Michael R.

2012-01-01

Atomization and fountain formation is a well-known phenomenon that occurs when a focused ultrasound wave in liquid encounters an air interface. High intensity focused ultrasound (HIFU) has been shown to fractionate tissue into submicron-size fragments in a process termed boiling histotripsy, wherein the focused ultrasound wave superheats the tissue at the focus, producing a millimetre-size boiling or vapour bubble in several milliseconds. Yet the question of how this millimetre-size boiling bubble creates submicron-size tissue fragments remains. The hypothesis of this work is that tissue can behave as a liquid such that it forms a fountain and atomization within the vapour bubble produced in boiling histotripsy. We describe an experiment, in which a 2-MHz HIFU transducer (maximum in situ intensity of 24,000 W/cm2) was aligned with an air-tissue interface meant to simulate the boiling bubble. Atomization and fountain formation were observed with high-speed photography and resulted in tissue erosion. Histological examination of the atomized tissue showed whole and fragmented cells and nuclei. Air-liquid interfaces were also filmed. Our conclusion was that HIFU can fountain and atomize tissue. Although this process does not entirely mimic what was observed in liquids, it does explain many aspects of tissue fractionation in boiling histotripsy. PMID:23159812

THE FREEZING POINT DEPRESSION OF MAMMALIAN TISSUES AFTER SUDDEN HEATING IN BOILING DISTILLED WATER

PubMed Central

Appelboom, Johannes W. Th.; Brodsky, William A.; Tuttle, William S.; Diamond, Israel

1958-01-01

The calculated freezing point depression of freshly excised boiled mammalian tissue is approximately the same as that of plasma. The boiling procedure was chosen to eliminate the influence of metabolism on the level of the freezing point depression. Problems created by the boiling, such as equilibrium between tissue and diluent, change in activity coefficient by dilution, and loss of CO2 content, are discussed. A frozen crushed tissue homogenate is hypertonic to plasma. Boiling and dilution of such hypertonic homogenate exposed to room temperature for 5 to 15 minutes did not produce significant or unexplicable decreases in its osmotic activity. Moreover, freezing and crushing of a boiled diluted tissue did not produce any increase of the isoosmotic level of freezing point depression. It is possible to explain these data either with the hypothesis of hypertonic cell fluid or with that of isotonic cell fluid. In the case of an assumed isotonic cell fluid, data can be explained with one assumption, experimentally backed. In the case of an assumed hypertonic theory data can be explained only with the help of at least three ad hoc postulates. The data support the validity of the classical concept which holds that cell fluid is isotonic to extracellular fluid. PMID:13563805

Numerical Modeling of Propellant Boil-Off in a Cryogenic Storage Tank

NASA Technical Reports Server (NTRS)

Majumdar, A. K.; Steadman, T. E.; Maroney, J. L.; Sass, J. P.; Fesmire, J. E.

2007-01-01

A numerical model to predict boil-off of stored propellant in large spherical cryogenic tanks has been developed. Accurate prediction of tank boil-off rates for different thermal insulation systems was the goal of this collaboration effort. The Generalized Fluid System Simulation Program, integrating flow analysis and conjugate heat transfer for solving complex fluid system problems, was used to create the model. Calculation of tank boil-off rate requires simultaneous simulation of heat transfer processes among liquid propellant, vapor ullage space, and tank structure. The reference tank for the boil-off model was the 850,000 gallon liquid hydrogen tank at Launch Complex 39B (LC- 39B) at Kennedy Space Center, which is under study for future infrastructure improvements to support the Constellation program. The methodology employed in the numerical model was validated using a sub-scale model and tank. Experimental test data from a 1/15th scale version of the LC-39B tank using both liquid hydrogen and liquid nitrogen were used to anchor the analytical predictions of the sub-scale model. Favorable correlations between sub-scale model and experimental test data have provided confidence in full-scale tank boil-off predictions. These methods are now being used in the preliminary design for other cases including future launch vehicles

IR-thermography-based investigation of critical heat flux in subcooled flow boiling of water at atmospheric and high pressure conditions

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

Bucci, Matteo; Seong, Jee H.; Buongiorno, Jdacopo

Here we report on MIT’s THM work in Q4 2016 and Q1 2017. The goal of this project is to design, construct and execute tests of flow boiling critical heat flux (CHF) at high-pressure using high-resolution and high-speed video and infrared (IR) thermometry, to generate unique data to inform the development of and validate mechanistic boiling heat transfer and CHF models. In FY2016, a new test section was designed and fabricated. Data was collected at atmospheric conditions at 10, 25 and 50 K subcoolings, and three mass fluxes, i.e. 500, 750 and 1000 kg/m2/s. Starting in Q4 2016 and continuingmore » forward, new post-processing techniques have been developed to analyze the data collected. These new algorithms analyze the time-dependent temperature and heat flux distributions to calculate nucleation site density, nucleation frequency, growth and wait time, dry area fraction, and the complete heat flux partitioning. In Q1 2017 a new flow boiling loop was designed and constructed to support flow boiling tests up 10 bar pressure and 180 °C. Initial shakedown and testing has been completed. The flow loop and test section are now ready to begin high-pressure flow boiling testing.« less

Comparison of the Digestibility of the Major Peanut Allergens in Thermally Processed Peanuts and in Pure Form

PubMed Central

Maleki, Soheila J.; Schmitt, David A.; Galeano, Maria; Hurlburt, Barry K.

2014-01-01

It has been suggested that the boiling or frying of peanuts leads to less allergenic products than roasting. Here, we have compared the digestibility of the major peanut allergens in the context of peanuts subjected to boiling, frying or roasting and in purified form. The soluble peanut extracts and the purified allergens were digested with either trypsin or pepsin and analyzed by gel electrophoresis and western blot. T-cell proliferation was measured for the purified allergens. In most cases, boiled and raw peanut proteins were similarly digestible, but the Ara h 1 protein in the boiled extracts was more resistant to digestion. Most proteins from fried and roasted peanuts were more resistant to digestion than in raw and boiled samples, and more IgE binding fragments survived digestion. High-molecular-weight fragments of Ara h1 were resistant to digestion in fried and roasted samples. Ara h 1 and Ara h 2 purified from roasted peanuts were the most resistant to digestion, but differed in their ability to stimulate T-cells. The differences in digestibility and IgE binding properties of the major allergens in roasted, fried and boiled peanuts may not explain the difference between the prevalence of peanut allergy in different countries that consume peanut following these varied processing methods. PMID:28234320

Microbiological effectiveness and cost of boiling to disinfect drinking water in rural Vietnam.

PubMed

Clasen, Thomas F; Thao, Do Hoang; Boisson, Sophie; Shipin, Oleg

2008-06-15

Despite certain shortcomings, boiling is still the most common means of treating water in the home and the benchmark against which alternative household-based disinfection and filtration methods must be measured. We assessed the microbiological effectiveness and cost of boiling among a vulnerable population relying on unimproved water sources and commonly practicing boiling as a means of disinfecting water. In a 12 week study among 50 households from a rural community in Vietnam, boiling was associated with a 97% reduction in geometric mean thermotolerant coliforms (TTCs) (p < 0.001). Despite high levels of faecal contamination in source water, 37% of stored water samples from self-reported boilers met the WHO standard for safe drinking water (0 TTC/100 mL), and 38.3% fell within the low risk category (1--10 TTC/100 mL). Nevertheless, 60.5% of stored drinking water samples were positive for TTC, with 22.2% falling into the medium risk category (11--100 TTC/100 mL). The estimated cost of wood used to boil water was US$ 0.272 per month for wood collectors and US$ 1.68 per month for wood purchasers, representing approximately 0.48% to 1.04%, respectively, of the average monthly income of participating households.

Skin whitening and anti-corrugation activities of glycoprotein fractions from liquid extracts of boiled sea cucumber.

PubMed

Kim, So Jung; Park, So Yun; Hong, Sun-Mee; Kwon, Eun-Hye; Lee, Taek-Kyun

2016-10-01

To determine skin whitening and wrinkle improvement efficacy, glycoprotein fractions were extracted from liquid extracts of boiled sea cucumber and their effects on tyrosine and elastase inhibitory activities were assayed. Fractions above and below 50 kDa (>50 kDa and <50 kDa) were extracted via a series of steps involving: boiling, filtering, desalting and freeze drying. Cytotoxicity, skin whitening and wrinkle-removing effects of boiled liquid were determined. Our MTT data showed that neither glycoprotein fraction of boiled liquid induces cellular cytotoxicity up to a concentration of 10 mg/mL treatment of the mouse melanoma cell line, B16F10, with 10 mg/mL >50 kDa enhanced tyrosinase and elastase inhibitory activities by 50.84% and 28.78%, respectively. Correlations of the >50 kDa concentration with tyrosinase inhibitory (R2 = 0.968) and elastase inhibitory (R2 = 0.983) efficacy were significant. >50 kDa glycoprotein fraction isolated from liquid extracts of boiled sea cucumber, which can serve as a functional cosmetic ingredient for whitening and wrinkle improvement of skin. Copyright © 2016 Hainan Medical University. Production and hosting by Elsevier B.V. All rights reserved.

Marangoni Effects in the Boiling of Binary Fluid Mixtures

NASA Technical Reports Server (NTRS)

Ahmed, Sayeed; Carey, Van P.; Motil, Brian

1996-01-01

Results of very recent experimental studies indicate that during nucleate boiling in some binary mixture, Marangoni effects augment the gravity driven flow of liquid towards the heated surface. With gravity present, it is impossible to separate the two effects. The reduced gravity environment gives an unique opportunity to explore th role of Marangoni effects on the boiling mechanisms free of gravitational body forces that obscure the role of such effects. However, recent experimental results suggest that under reduced gravity conditions, Marangoni effects is the dominant mechanism of vapor-liquid exchange at the surface for some binary mixture. To further explore such effects, experiments have been conducted with water/2-propanol mixtures at three different concentrations under normal gravity with different orientations of the heater surface and under reduce gravity aboard the DC-9 aircraft at NASA Lewis Research Center. The system pressure was sub atmospheric (approx. 8 kP at 1g(n)) and the bulk liquid temperature varied from low subcooling to near saturation. The molar concentrations of 2-propanol tested were 0.015, 0.025, and 0.1. Boiling curves were obtained both for high gravity (approx. 2g(n)) and reduce gravity (approx. 0.01g(n)). For each concentration of 2-propanol, the critical heat flux has been determined in the flight experiments only for reduced gravity conditions. Comparison of boiling curves and CHF obtained under l-g(n) an reduced gravity indicates that boiling mechanism in this mixtures is nearly independent of gravity. The results also indicate that the Marangoni mechanism is strong enough in these mixtures to sustain the boiling under reduced gravity conditions.

Shock-induced heating and millisecond boiling in gels and tissue due to high intensity focused ultrasound

PubMed Central

Canney, Michael S.; Khokhlova, Vera A.; Bessonova, Olga V.; Bailey, Michael R.; Crum, Lawrence A.

2009-01-01

Nonlinear propagation causes high intensity ultrasound waves to distort and generate higher harmonics, which are more readily absorbed and converted to heat than the fundamental frequency. Although such nonlinear effects have previously been investigated and found not to significantly alter high intensity focused ultrasound (HIFU) treatments, two results reported here change this paradigm. One is that at clinically relevant intensity levels, HIFU waves not only become distorted but form shock waves in tissue. The other is that the generated shock waves heat the tissue to boiling in much less time than predicted for undistorted or weakly distorted waves. In this study, a 2-MHz HIFU source operating at peak intensities up to 25,000 W/cm2 was used to heat transparent tissue-mimicking phantoms and ex vivo bovine liver samples. Initiation of boiling was detected using high-speed photography, a 20-MHz passive cavitation detector, and fluctuation of the drive voltage at the HIFU source. The time to boil obtained experimentally was used to quantify heating rates and was compared to calculations using weak shock theory and the shock amplitudes obtained from nonlinear modeling and from measurements with a fiber optic hydrophone. As observed experimentally and predicted by calculations, shocked focal waveforms produced boiling in as little as 3 ms and the time to initiate boiling was sensitive to small changes in HIFU output. Nonlinear heating due to shock waves is therefore important to HIFU and clinicians should be aware of the potential for very rapid boiling since it alters treatments. PMID:20018433

Evaluation of different cooking conditions on broccoli (Brassica oleracea var. italica) to improve the nutritional value and consumer acceptance.

PubMed

Bongoni, Radhika; Verkerk, Ruud; Steenbekkers, Bea; Dekker, Matthijs; Stieger, Markus

2014-09-01

The objective of this study was to gain insights into the effect of the cooking method on the liking as well as the retention of glucosinolates in broccoli. With this knowledge it can be concluded whether the health aspects of broccoli be improved by the cooking method without deteriorating sensory perception. For this, broccoli was cooked by methods commonly applied by consumers: boiling with a cold (water) start; boiling with a hot (water) start; and steaming. Firmness, greenness and amount of total glucosinolates in cooked broccoli were instrumentally determined. Sensory evaluation by untrained consumers (n = 99) for liking and sensory attributes intensity rating were performed on broccoli cooked by steaming and boiling-cold start at three time points, which resulted in 'high', 'medium', 'low' firm broccoli samples. At the end of cooking, steaming showed an increase in the amount of total glucosinolates (+17%). Boiling-hot start (-41%) and boiling-cold start (-50%) showed a decrease in amount of total glucosinolates. Sensory evaluation did not show statistically significant differences between steaming and boiling-cold start in liking at 'high' and 'medium' firmness; and in the attribute intensity ratings (except for juiciness at 'medium' firmness, and flavour at 'medium' and 'low' firmness). This study demonstrates that medium firm broccoli showed optimum liking and that steaming compared to boiled-cold start showed higher amount of glucosinolates. It is concluded that the health aspects of broccoli can be improved without reducing the sensory aspects by optimising the cooking method.

Changes in the Microbial Composition of Microbrewed Beer during the Process in the Actual Manufacturing Line.

PubMed

Kim, S A; Jeon, S H; Kim, N H; Kim, H W; Lee, N Y; Cho, T J; Jung, Y M; Lee, S H; Hwang, I G; Rhee, M S

2015-12-01

This study investigated changes in the microbial composition of microbrewed beer during the manufacturing processes and identified potential microbial hazards, effective critical quality control points, and potential contamination routes. Comprehensive quantitative (aerobic plate count, lactic acid bacteria, fungi, acetic acid bacteria, coliforms, and Bacillus cereus) and qualitative (Escherichia coli and eight foodborne pathogens) microbiological analyses were performed using samples of raw materials (malt and manufacturing water), semiprocessed products (saccharified wort, boiled wort, and samples taken during the fermentation and maturation process), and the final product obtained from three plants. The initial aerobic plate count and lactic acid bacteria counts in malt were 5.2 and 4.3 log CFU/g, respectively. These counts were reduced to undetectable levels by boiling but were present at 2.9 and 0.9 log CFU/ml in the final product. Fungi were initially present at 3.6 log CFU/g, although again, the microbes were eliminated by boiling; however, the level in the final product was 4.6 log CFU/ml. No E. coli or foodborne pathogens (except B. cereus) were detected. B. cereus was detected at all stages, although it was not present in the water or boiled wort (total detection rate ¼ 16.4%). Results suggest that boiling of the wort is an effective microbial control measure, but careful management of raw materials and implementation of effective control measures after boiling are needed to prevent contamination of the product after the boiling step. The results of this study may constitute useful and comprehensive information regarding the microbiological quality of microbrewed beer.

Raw milk from vending machines: Effects of boiling, microwave treatment, and refrigeration on microbiological quality.

PubMed

Tremonte, Patrizio; Tipaldi, Luca; Succi, Mariantonietta; Pannella, Gianfranco; Falasca, Luisa; Capilongo, Valeria; Coppola, Raffaele; Sorrentino, Elena

2014-01-01

In Italy, the sale of raw milk from vending machines has been allowed since 2004. Boiling treatment before its use is mandatory for the consumer, because the raw milk could be an important source of foodborne pathogens. This study fits into this context with the aim to evaluate the microbiological quality of 30 raw milk samples periodically collected (March 2013 to July 2013) from 3 vending machines located in Molise, a region of southern Italy. Milk samples were stored for 72 h at 4 °C and then subjected to different treatments, such as boiling and microwaving, to simulate domestic handling. The results show that all the raw milk samples examined immediately after their collection were affected by high microbial loads, with values very close to or even greater than those acceptable by Italian law. The microbial populations increased during refrigeration, reaching after 72 h values of about 8.0 log cfu/mL for Pseudomonas spp., 6.5 log cfu/mL for yeasts, and up to 4.0 log cfu/mL for Enterobacteriaceae. Boiling treatment, applied after 72 h to refrigerated milk samples, caused complete decontamination, but negatively affected the nutritional quality of the milk, as demonstrated by a drastic reduction of whey proteins. The microwave treatment at 900 W for 75 s produced microbiological decontamination similar to that of boiling, preserving the content in whey proteins of milk. The microbiological characteristics of raw milk observed in this study fully justify the obligation to boil the raw milk from vending machines before consumption. However, this study also showed that domestic boiling causes a drastic reduction in the nutritional value of milk. Microwave treatment could represent a good alternative to boiling, on the condition that the process variables are standardized for safe domestic application. Copyright © 2014 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Investigation of Critical Heat Flux in Reduced Gravity Using Photomicrographic Techniques

NASA Technical Reports Server (NTRS)

Mudawar, Issam; Zhang, Hui

2003-01-01

Experiments were performed to examine the effects of body force on flow boiling critical heat flux (CHF). FC-72 was boiled along one wall of a transparent rectangular flow channel that permitted photographic study of the vapor-liquid interface just prior to CHF. High-speed video imaging techniques were used to identify dominant CHF mechanisms corresponding to different flow orientations and liquid velocities. Six different CHF regimes were identified: Wavy Vapor Layer, Pool Boiling, Stratification, Vapor Counterflow, Vapor Stagnation, and Separated Concurrent Vapor Flow. CHF showed significant sensitivity to orientation for flow velocities below 0.2 m/s, where extremely low CHF values where measured, especially with downward-facing heated wall and downflow orientations. High flow velocities dampened the effects of orientation considerably. The CHF data were used to assess the suitability of previous CHF models and correlations. It is shown the Interfacial Lift-off Model is very effective at predicting CHF for high velocities at all orientations. The flooding limit, on the other hand, is useful at estimating CHF at low velocities and for downflow orientations. A new method consisting of three dimensionless criteria is developed for determining the minimum flow velocity required to overcome body force effects on near-saturated flow boiling CHF. Vertical upflow boiling experiments were performed in pursuit of identifying the trigger mechanism for subcooled flow boiling CHF. While virtually all prior studies on flow boiling CHF concern the prediction or measurement of conditions that lead to CHF, this study was focused on events that take place during the CHF transient. High-speed video imaging and photomicrographic techniques were used to record the transient behavior of interfacial features from the last steady-state power level before CHF until the moment of power cut-off following CHF. The video records show the development of a wavy vapor layer which propagates along the heated wall, permitting cooling prior to CHF only in wetting fronts corresponding to the wave troughs. Image analysis software was developed to estimate void fraction from the individual video images. The void fraction records for subcooled flow boiling show the CHF transient is accompanied by gradual lift-off of wetting fronts culminating in some maximum vapor layer mean thickness, following which the vapor layer begins to thin down as the transition to film boiling ensues. This study proves the Interfacial Lift-off Model, which has been validated for near-saturated flow boiling CHF, is equally valid for subcooled conditions.

Enhanced Boiling on Micro-Configured Composite Surfaces Under Microgravity Conditions

NASA Technical Reports Server (NTRS)

Zhang, Nengli; Chai, An-Ti

1999-01-01

In order to accommodate the growing thermal management needs of future space platforms, several two-phase active thermal control systems (ATCSs) have evolved and were included in the designs of space stations. Compared to the pumped single-phase liquid loops used in the conventional Space Transportation System and Spacelab, ATCSs offer significant benefits that may be realized by adopting a two-phase fluid-loop system. Alternately, dynamic power systems (DPSs), based on the Rankine cycle, seem inevitably to be required to supply the electrical power requirements of expanding space activities. Boiling heat transfer is one of the key technologies for both ATCSs and DPSs. Nucleate boiling near critical heat flux (CHF) can transport very large thermal loads with much smaller device size and much lower pumping power. However, boiling performance deteriorates in a reduced gravity environment and operation in the CHF regime is precarious because any slight overload will cause the heat transfer to suddenly move to the film boiling regime, which in turn, will result in burnout of the heat transfer surfaces. New materials, such as micro-configured metal-graphite composites, can provide a solution for boiling enhancement. It has been shown experimentally that this type of material manifests outstanding boiling heat transfer performance and their CHF is also extended to higher values. Due to the high thermal conductivity of graphite fiber (up to 1,200 W/m-K in the fiber direction), the composite surfaces are non-isothermal during the boiling process. The composite surfaces are believed to have a much wider safe operating region (a more uniform boiling curve in the CHF regime) because non-isothermal surfaces have been found to be less sensitive to variations of wall superheat in the CHF regime. The thermocapillary forces formed by the temperature difference between the fiber tips and the metal matrix play a more important role than the buoyancy in the bubble detachment, for the bubble detachment manifests itself by a necking process which should not be weakened by reduced gravity. In addition, the composite surfaces introduce no extra pressure drop, no fouling and do not impose significant primary or maintenance costs. All of these suggest that this type of composite is an ideal material for the challenge of accounting for both reliability and economy of the relevant components applied in the ATCSs, the DPSs and other devices in future space missions. The aim of the proposed work is to experimentally investigate high nucleate pool boiling performance on a micro-configured metal-graphite composite surface and to determine the mechanisms of the nucleate boiling heat transfer both experimentally and theoretically. Freon-113 and water will be used as the test liquids to investigate wettability effects on boiling characteristics. The Cu-Gr and Al-Gr composites with various volume fractions of graphite fibers will be tested to obtain the heat transfer characteristic data in the nucleate boiling region and in the CHF regime. In the experiments, the bubble emission and coalescence processes will be recorded by a video camera with a magnifying borescope probe immersed in the working fluid. The temperature profile in the thermal boundary layer on the composite surfaces will be measured by a group of micro thermocouples consisting of four ultra fine micro thermocouples. This instrument was developed and successfully used to measure the temperature profile of evaporating liquid thin layers by the proposers in a study performed at the NASA/Lewis Research Center. A two tier model to explain the nucleate boiling process and the performance enhancement on the composite surfaces has been suggested by the authors. According to the model, the thicknesses of the microlayer and the macrolayer underneath the bubbles and mushrooms, can be estimated by the geometry of the composite surface. The experimental results will be compared to the predictions from the model, and in turn, to revise and improve it.

A Closer Look at Trends in Boiling Points of Hydrides: Using an Inquiry-Based Approach to Teach Intermolecular Forces of Attraction

ERIC Educational Resources Information Center

Glazier, Samantha; Marano, Nadia; Eisen, Laura

2010-01-01

We describe how we use boiling-point trends of group IV-VII hydrides to introduce intermolecular forces in our first-year general chemistry classes. Starting with the idea that molecules in the liquid state are held together by some kind of force that must be overcome for boiling to take place, students use data analysis and critical reasoning to…

Bubble Dynamics, Two-Phase Flow, and Boiling Heat Transfer in Microgravity

NASA Technical Reports Server (NTRS)

Chung, Jacob N.

1996-01-01

The objective of the research is to study the feasibility of employing an external force to replace the buoyancy force in order to maintain nucleate boiling in microgravity. We have found that a bulk velocity field, an electric field and an acoustic field could each play the role of the gravity field in microgravity. Nucleate boiling could be maintained by any one of the three external force fields in space.

Boiling heat transfer to LN2 and LH2 - Influence of surface orientation and reduced body forces

NASA Technical Reports Server (NTRS)

Merte, H., Jr.; Oker, E.; Littles, J. W.

1973-01-01

The quantitative determination of the influence of heater surface orientation and gravity on nucleate pool boiling of liquid nitrogen and liquid hydrogen is described. A transient calorimeter technique, well suited for obtaining pool boiling data under reduced gravity and used earlier by Clark and Merte (1963), was employed after being adapted to flat a surface whose orientation could be varied. The obtained determination results are reviewed.

SUPERHEATING IN A BOILING WATER REACTOR

DOEpatents

Treshow, M.

1960-05-31

A boiling-water reactor is described in which the steam developed in the reactor is superheated in the reactor. This is accomplished by providing means for separating the steam from the water and passing the steam over a surface of the fissionable material which is not in contact with the water. Specifically water is boiled on the outside of tubular fuel elements and the steam is superheated on the inside of the fuel elements.

MSG test report-steady-state heat transfer. [LMFBR

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

Harty, R.B.

This report documents the results of the Steady-State Heat Transfer Tests conducted on the AI Modular Steam Generator (MSG), at the Sodium Component Test Installation (SCTI) of the Liquid Metal Engineering Center. Heat transfer and pressure drop performance data are given along with current predictions of performance. Departure from nucleate boiling characteristics is given. A dispersed flow film boiling model, employing thermal nonequilibrium, was used to analyze data in the film boiling region.

16. RW Meyer Sugar Mill: 18761889. Boiling House Interior, 1878. ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

16. RW Meyer Sugar Mill: 1876-1889. Boiling House Interior, 1878. View: Looking from west to east through boiling house. The sorghum pan is on the right. The beams; joists, and trusses are of northwest pine; side boards are of redwood. A foundation line of a loading dock and smokestack are in the foreground. Both end walls have deteriorated completely. - R. W. Meyer Sugar Mill, State Route 47, Kualapuu, Maui County, HI

Boiling on Microconfigured Composite Surfaces Enhanced

NASA Technical Reports Server (NTRS)

Chao, David F.

2000-01-01

Boiling heat transfer is one of the key technologies for the two-phase active thermal-control system used on space platforms, as well as for the dynamic power systems aboard the International Space Station. Because it is an effective heat transfer mode, boiling is integral to many space applications, such as heat exchangers and other cooling devices. Nucleate boiling near the critical heat flux (CHF) can transport very large thermal loads with a much smaller device and much lower pumping power than for single-phase heat exchangers. However, boiling performance sharply deteriorates in a reduced-gravity environment, and operation in the CHF regime is somewhat perilous because of the risk of burnout to the device surface. New materials called microconfigured metal-graphite composites can enhance boiling. The photomicrograph shows the microconfiguration (x3000) of the copper-graphite (Cu-Gr) surface as viewed by scanning electronic microscope. The graphite fiber tips appear as plateaus with rugged surfaces embedded in the copper matrix. It has been experimentally demonstrated that this type of material manifests excellent boiling heat transfer performance characteristics and an increased CHF. Nonisothermal surfaces were less sensitive to variations of wall superheat in the CHF regime. Because of the great difference in conductivity between the copper base and the graphite fiber, the composite surfaces have a nonisothermal surface characteristic and, therefore, will have a much larger "safe" operating region in the CHF regime. In addition, the thermocapillary forces induced by the temperature differences between the fiber tips and the metal matrix play an important role in bubble detachment, and may not be adversely affected in a reduced-gravity environment. All these factors indicate that microconfigured composites may improve the reliability and economy (dominant factors in all space applications) of various thermal components found on spacecraft during future missions.

Effects of Boiling Drinking Water on Diarrhea and Pathogen-Specific Infections in Low- and Middle-Income Countries: A Systematic Review and Meta-Analysis

PubMed Central

Cohen, Alasdair; Colford, John M.

2017-01-01

Abstract. Globally, approximately 2 billion people lack microbiologically safe drinking water. Boiling is the most prevalent household water treatment method, yet evidence of its health impact is limited. To conduct this systematic review, we searched four online databases with no limitations on language or publication date. Studies were eligible if health outcomes were measured for participants who reported consuming boiled and untreated water. We used reported and calculated odds ratios (ORs) and random-effects meta-analysis to estimate pathogen-specific and pooled effects by organism group and nonspecific diarrhea. Heterogeneity and publication bias were assessed using I2, meta-regression, and funnel plots; study quality was also assessed. Of the 1,998 records identified, 27 met inclusion criteria and reported extractable data. We found evidence of a significant protective effect of boiling for Vibrio cholerae infections (OR = 0.31, 95% confidence interval [CI] = 0.13–0.79, N = 4 studies), Blastocystis (OR = 0.35, 95% CI = 0.17–0.69, N = 3), protozoal infections overall (pooled OR = 0.61, 95% CI = 0.43–0.86, N = 11), viral infections overall (pooled OR = 0.83, 95% CI = 0.7–0.98, N = 4), and nonspecific diarrheal outcomes (OR = 0.58, 95% CI = 0.45–0.77, N = 7). We found no evidence of a protective effect for helminthic infections. Although our study was limited by the use of self-reported boiling and non-experimental designs, the evidence suggests that boiling provides measureable health benefits for pathogens whose transmission routes are primarily water based. Consequently, we believe a randomized controlled trial of boiling adherence and health outcomes is needed. PMID:29016318

A Ghost Fluid/Level Set Method for boiling flows and liquid evaporation: Application to the Leidenfrost effect

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

Rueda Villegas, Lucia; Alis, Romain; Lepilliez, Mathieu

2016-07-01

The development of numerical methods for the direct numerical simulation of two-phase flows with phase change, in the framework of interface capturing or interface tracking methods, is the main topic of this study. We propose a novel numerical method, which allows dealing with both evaporation and boiling at the interface between a liquid and a gas. Indeed, in some specific situations involving very heterogeneous thermodynamic conditions at the interface, the distinction between boiling and evaporation is not always possible. For instance, it can occur for a Leidenfrost droplet; a water drop levitating above a hot plate whose temperature is muchmore » higher than the boiling temperature. In this case, boiling occurs in the film of saturated vapor which is entrapped between the bottom of the drop and the plate, whereas the top of the water droplet evaporates in contact of ambient air. The situation can also be ambiguous for a superheated droplet or at the contact line between a liquid and a hot wall whose temperature is higher than the saturation temperature of the liquid. In these situations, the interface temperature can locally reach the saturation temperature (boiling point), for instance near a contact line, and be cooler in other places. Thus, boiling and evaporation can occur simultaneously on different regions of the same liquid interface or occur successively at different times of the history of an evaporating droplet. Standard numerical methods are not able to perform computations in these transient regimes, therefore, we propose in this paper a novel numerical method to achieve this challenging task. Finally, we present several accuracy validations against theoretical solutions and experimental results to strengthen the relevance of this new method.« less

Bench-scale screening tests for a boiling sodium-potassium alloy solar receiver

NASA Astrophysics Data System (ADS)

Moreno, J. B.; Moss, T. A.

1993-06-01

Bench-scale tests were carried out in support of the design of a second-generation 75-kW(sub t) reflux pool-boiler solar receiver. The receiver will be made from Haynes Alloy 230 and will contain the sodium-potassium alloy NaK-78. The bench-scale tests used quartz lamp heated boilers to screen candidate boiling stabilization materials and methods at temperatures up to 750 degree C. Candidates that provided stable boiling were tested for hot-restart behavior. Poor stability was obtained with single 1/4-inch diameter patches of powdered metal hot press sintered onto the wetted side of the heat-input area. Laser-drilled and electric discharge machined cavities in the heated surface also performed poorly. Small additions of xenon, and heated-surface tilt out of the vertical, dramatically improved poor boiling stability; additions of helium or oxygen did not. The most stable boiling was obtained when the entire heat-input area was covered by a powdered-metal coating. The effect of heated-area size was assessed for one coating: at low incident fluxes, when even this coating performed poorly, increasing the heated-area size markedly improved boiling stability. Good hot-restart behavior was not observed with any candidate, although results were significantly better with added xenon in a boiler shortened from 3 to 2 feet. In addition to the screening tests, flash-radiography imaging of metal-vapor bubbles during boiling was attempted. Contrary to the Cole-Rohsenow correlation, these bubble-size estimates did not vary with pressure; instead they were constant, consistent with the only other alkali metal measurements, but about 1/2 their size.

A high-fidelity approach towards simulation of pool boiling

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

Yazdani, Miad; Radcliff, Thomas; Soteriou, Marios

2016-01-15

A novel numerical approach is developed to simulate the multiscale problem of pool-boiling phase change. The particular focus is to develop a simulation technique that is capable of predicting the heat transfer and hydrodynamic characteristics of nucleate boiling and the transition to critical heat flux on surfaces of arbitrary shape and roughness distribution addressing a critical need to design enhanced boiling heat transfer surfaces. The macro-scale of the phase change and bubble dynamics is addressed through employing off-the-shelf Computational Fluid Dynamics (CFD) methods for interface tracking and interphase mass and energy transfer. The micro-scale of the microlayer, which forms atmore » early stage of bubble nucleation near the wall, is resolved through asymptotic approximation of the thin-film theory which provides a closed-form solution for the distribution of the micro-layer and its influence on the evaporation process. In addition, the sub-grid surface roughness is represented stochastically through probabilistic density functions and its role in bubble nucleation and growth is then represented based on the thermodynamics of nucleation process. This combination of deterministic CFD, local approximation, and stochastic representation allows the simulation of pool boiling on any surface with known roughness and enhancement characteristics. The numerical model is validated for dynamics and hydrothermal characteristics of a single nucleated bubble on a flat surface against available literature data. In addition, the prediction of pool-boiling heat transfer coefficient is verified against experimental measurements as well as reputable correlations for various roughness distributions and different surface orientations. Finally, the model is employed to demonstrate pool-boiling phenomenon on enhanced structures with reentrance cavities and to explore the effect of enhancement feature design on thermal and hydrodynamic characteristics of these surfaces.« less

The Effect of Dissolved Air on the Cooling Performance of a Partially Confined FC-72 Spray

DTIC Science & Technology

2008-07-01

95 iv LIST OF FIGURES Figure 1: Heat transfer coefficients: various processes and coolants ( Mudawar , 2001) .....1 Figure 2...various processes and coolants ( Mudawar , 2001). 2 In two-phase cooling a phase change of liquid to vapor, or boiling, occurs. The boiling...possible in flow boiling is also affected by the velocity of the flow and the amount of subcooling of the fluid ( Mudawar and Maddox, 1989). One highly

Effects of cooking on concentrations of polychlorinated dibenzo-p-dioxins and related compounds in fish and meat.

PubMed

Hori, Tsuguhide; Nakagawa, Reiko; Tobiishi, Kazuhiro; Iida, Takao; Tsutsumi, Tomoaki; Sasaki, Kumiko; Toyoda, Masatake

2005-11-02

We investigated the cooking-induced changes in concentrations of polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and dioxin-like polychlorinated biphenyls (PCBs) (dioxins) using mackerel and beef. The concentrations of dioxins (29 congeners) were determined by isomer specific analyses and were compared between uncooked and cooked samples. The cooking procedures examined in this study included grilling as a fillet, boiling as a fillet, and boiling as tsumire (small, hand-rolled balls) for mackerel and boiling as a slice, broiling as a slice, and broiling as a hamburger for beef. Three trials were carried out for each cooking method. Generally, concentrations of dioxins were reduced in every cooking trial. When nondetected congener concentrations were assumed to be half the limit of detection for mackerel, the maximum percentage reductions of total concentrations given as 2,3,7,8-tetraCDD equivalents (TEQ) were 31% in grilling as a slice, 14% in boiling as a slice, and 21% in boiling as tsumire under the conditions of this study. In contrast, for beef, the reductions were 42% in boiling as a slice, 42% in broiling as a slice, and 44% in broiling as a hamburger. These results suggest that ordinary cooking processes with heating undoubtedly reduce the dioxin content in animal products, and the reductions estimated should be considered when dioxin intake is evaluated using contamination data for individual food items.

Cork boiling wastewater treatment and reuse through combination of advanced oxidation technologies.

PubMed

Ponce-Robles, L; Miralles-Cuevas, S; Oller, I; Agüera, A; Trinidad-Lozano, M J; Yuste, F J; Malato, S

2017-03-01

Industrial preparation of cork consists of its immersion for approximately 1 hour in boiling water. The use of herbicides and pesticides in oak tree forests leads to absorption of these compounds by cork; thus, after boiling process, they are present in wastewater. Cork boiling wastewater shows low biodegradability and high acute toxicity involving partial inhibition of their biodegradation when conventional biological treatment is applied. In this work, a treatment line strategy based on the combination of advanced physicochemical technologies is proposed. The final objective is the reuse of wastewater in the cork boiling process; thus, reducing consumption of fresh water in the industrial process itself. Coagulation pre-treatment with 0.5 g/L of FeCl 3 attained the highest turbidity elimination (86 %) and 29 % of DOC elimination. Similar DOC removal was attained when using 1 g/L of ECOTAN BIO (selected for ozonation tests), accompanied of 64 % of turbidity removal. Ozonation treatments showed less efficiency in the complete oxidation of cork boiling wastewater, compared to solar photo-Fenton process, under the studied conditions. Nanofiltration system was successfully employed as a final purification step with the aim of obtaining a high-quality reusable permeate stream. Monitoring of unknown compounds by LC-QTOF-MS allowed the qualitative evaluation of the whole process. Acute and chronic toxicity as well as biodegradability assays were performed throughout the whole proposed treatment line.

High Intensity Focused Ultrasound Monitoring using Harmonic Motion Imaging for Focused Ultrasound (HMIFU) under boiling or slow denaturation conditions

PubMed Central

Hou, Gary Y.; Marquet, Fabrice; Wang, Shutao; Apostolakis, Iason-Zacharias; Konofagou, Elisa E.

2015-01-01

Harmonic Motion Imaging for Focused Ultrasound (HMIFU) is a recently developed High-Intensity Focused Ultrasound (HIFU) treatment monitoring method that utilizes an amplitude-modulated therapeutic ultrasound beam to induce an oscillatory radiation force at the HIFU focus and estimates the focal tissue displacement to monitor the HIFU thermal treatment. In this study, the performance of HMIFU under acoustic, thermal and mechanical effects were investigated. The performance of HMIFU was assessed in ex vivo canine liver specimens (n=13) under slow denaturation or boiling regimes. Passive Cavitation Detector (PCD) was used to assess the acoustic cavitation activity while a bare-wire thermocouple was used to monitor the focal temperature change. During lesioning with slow denaturation, high quality displacements (correlation coefficient above 0.97) were observed under minimum cavitation noise, indicating tissue the initial-softening-then-stiffening property change. During HIFU with boiling, HMIFU monitored a consistent change in lesion-to-background displacement contrast (0.46±0.37) despite the presence of strong cavitation noise due to boiling during lesion formation. Therefore, HMIFU effectively monitored softening-then-stiffening during lesioning under slow denaturation, and detected lesioning under boiling with a distinct change in displacement contrast under boiling in the presence of cavitation. In conclusion, HMIFU was shown effective in HIFU monitoring and lesioning identification without being significantly affected by cavitation noise. PMID:26168177

Effects of thermal treatments during cooking, microwave oven and boiling, on the unconjugated microcystin concentration in muscle of fish (Oreochromis niloticus).

PubMed

Guzmán-Guillén, Remedios; Prieto, Ana I; Moreno, Isabel; Soria, Ma Eugenia; Cameán, Ana M

2011-09-01

Understanding the factors that contribute to the risk from fish consumption is a relevant public health concern due to potential adverse effects of cyanobacterial toxins. The aim of this work was to study the influence of two usual cooking practices, microwave oven and boiling, on the microcystin (MCs) concentration in fish muscle (Tilapia, Oreochromis niloticus) spiked with a stock solution (500 μL) containing a mixture of three toxins (MC-LR, MC-RR, and MC-YR) (1.5 μg/mL of each toxin). Two different variables were investigated: time of cooking in the microwaves treatment (1 or 5 min), and way of boiling, "boiled muscle" or "continuously heated muscle". All samples were then lyophilized and MCs were extracted and purified (Oasis HLB cartridge) and quantified by HPLC-MS. Furthermore, the waters in which the samples boiled were also analyzed after their purification. The results suggest a reduction on MC-LR (36%) and MC-YR (24.6%) in samples cooked in the microwave for 5 min. Major changes were found when the fish was cooked by the continuous boiling, with a decrease of 45.0% (MC-RR), 56.4% (MC-YR) and 59.3% (MC-LR). More studies are necessary to elucidate the mechanisms involved when aquatic food is submitted to usual cooking practices. Copyright © 2011 Elsevier Ltd. All rights reserved.

Iron release from the Lucky Iron Fish®: safety considerations.

PubMed

Armstrong, Gavin R; Dewey, Cate E; Summerlee, Alastair Js

2017-01-01

The principal objective was to explore in greater detail safety issues with regard to the use of the Lucky Iron Fish® (fish) as a treatment for iron deficiency and iron deficiency anaemia in women in rural Cambodia. Experiments were done to determine: (1) purity of the iron in the fish by mass spectroscopy; (2) release of iron and contaminants released during boiling in water using inductive-ly-coupled plasma optical emission spectroscopy; (3) the impact of cooking time, acidity and number of fish in acidified water and two types of Khmer soups; and (4) drinkability of the water after boiling with different num-bers of fish. The fish is composed primarily of ferrous iron with less than 12% non-ferrous iron. Contaminants were either not detectable or levels were below the acceptable standards set by the World Health Organization. The length of time boiling the fish and the acidity of the water increased iron release but even with 5 fish boiled for 60 minutes, iron levels only approached levels where side effects are observed. Boiling one fish in water did not affect the perception of colour, smell or taste of the water but boiling in water with two or more fish resulted in the water being unpalatable which further limits the potential for iron toxicity from using the fish. The results suggest that the Lucky Iron Fish™ may be a safe treatment for iron deficiency.

DETERMINATION OF CONVECTIVE HEAT TRANSFER COEFFICIENT AT THE OUTER SURFACE OF A CRYOVIAL BEING PLUNGED INTO LIQUID NITROGEN.

PubMed

Wang, T; Zhao, G; Tang, H Y; Jiang, Z D

2015-01-01

Cell survival upon cryopreservation is affected by the cooling rate. However, it is difficult to model the heat transfer process or to predict the cooling curve of a cryoprotective agent (CPA) solution due to the uncertainty of its convective heat transfer coefficient (h). To measure the h and to better understand the heat transfer process of cryovials filled with CPA solution being plunged in liquid nitrogen. The temperatures at three locations of the CPA solution in a cryovial were measured. Different h values were selected after the cooling process was modeled as natural convection heat transfer, the film boiling and the nucleate boiling, respectively. And the temperatures of the selected points are simulated based on the selected h values. h was determined when the simulated temperature best fitted the experimental temperature. When the experimental results were best fitted, according to natural convection heat transfer model, h(1) = 120 W/(m(2)·K) while due to film boiling and nucleate boiling regimes h(f) = 5 W/(m(2)·K) followed by h(n) = 245 W/(m(2)·K). These values were verified by the differential cooling rates at the three locations of a cryovial. The heat transfer process during cooling in liquid nitrogen is better modeled as film boiling followed by nucleate boiling.

Single-bubble boiling under Earth's and low gravity

NASA Astrophysics Data System (ADS)

Khusid, Boris; Elele, Ezinwa; Lei, Qian; Tang, John; Shen, Yueyang

2017-11-01

Miniaturization of electronic systems in terrestrial and space applications is challenged by a dramatic increase in the power dissipation per unit volume with the occurrence of localized hot spots where the heat flux is much higher than the average. Cooling by forced gas or liquid flow appears insufficient to remove high local heat fluxes. Boiling that involves evaporation of liquid in a hot spot and condensation of vapor in a cold region can remove a significantly larger amount of heat through the latent heat of vaporization than force-flow cooling can carry out. Traditional methods for enhancing boiling heat transfer in terrestrial and space applications focus on removal of bubbles from the heating surface. In contrast, we unexpectedly observed a new boiling regime of water under Earth's gravity and low gravity in which a bubble was pinned on a small heater up to 270°C and delivered a heat flux up to 1.2 MW/m2 that was as high as the critical heat flux in the classical boiling regime on Earth .Low gravity measurements conducted in parabolic flights in NASA Boeing 727. The heat flux in flight and Earth's experiments was found to rise linearly with increasing the heater temperature. We will discuss physical mechanisms underlying heat transfer in single-bubble boiling. The work supported by NASA Grants NNX12AM26G and NNX09AK06G.

First on-sun test of NaK pool-boiler solar receiver

NASA Astrophysics Data System (ADS)

Moreno, J. B.; Andraka, C. E.; Moss, T. A.; Cordeiro, P. G.; Dudley, V. E.; Rawlinson, K. S.

During 1989-1990, a refluxing liquid-metal pool-boiler solar receiver designed for dish/Stirling application at 75 kW(sub t) throughput was successfully demonstrated at Sandia National Laboratories. Significant features of this receiver included (1) boiling sodium as the heat transfer medium, and (2) electric-discharge-machined (EDM) cavities as artificial nucleation sites to stabilize boiling. Following this first demonstration, a second-generation pool-boiler receiver that brings the concept closer to commercialization has been designed, constructed, and successfully tested. For long life, the new receiver is built from Haynes Alloy 230. For increased safety factors against film boiling and flooding, the absorber area and vapor-flow passages have been enlarged. To eliminate the need for trace heating, sodium has been replaced by the sodium-potassium alloy NaK-78. To reduce manufacturing costs, the receiver has a powdered-metal coating instead of EDM cavities for stabilization of boiling. To control incipient-boiling superheats, especially during hot restarts, it contains a small amount of xenon. In this paper, we present the receiver design and report the results of on-sun tests using a nominal 75 kW(sub t) test-bed concentrator to characterize boiling stability, hot-restart behavior, and thermal efficiency at temperatures up to 750 C. We also report briefly on late results from an advanced-concepts pool-boiler receiver.

Pool boiling of nanofluids on rough and porous coated tubes: experimental and correlation

NASA Astrophysics Data System (ADS)

Cieśliński, Janusz T.; Kaczmarczyk, Tomasz Z.

2014-06-01

The paper deals with pool boiling of water-Al2O3 and water- Cu nanofluids on rough and porous coated horizontal tubes. Commercially available stainless steel tubes having 10 mm outside diameter and 0.6 mm wall thickness were used to fabricate the test heater. The tube surface was roughed with emery paper 360 or polished with abrasive compound. Aluminium porous coatings of 0.15 mm thick with porosity of about 40% were produced by plasma spraying. The experiments were conducted under different absolute operating pressures, i.e., 200, 100, and 10 kPa. Nanoparticles were tested at the concentration of 0.01, 0.1, and 1% by weight. Ultrasonic vibration was used in order to stabilize the dispersion of the nanoparticles. It was observed that independent of operating pressure and roughness of the stainless steel tubes addition of even small amount of nanoparticles augments heat transfer in comparison to boiling of distilled water. Contrary to rough tubes boiling heat transfer coefficient of tested nanofluids on porous coated tubes was lower compared to that for distilled water while boiling on porous coated tubes. A correlation equation for prediction of the average heat transfer coefficient during boiling of nanofluids on smooth, rough and porous coated tubes is proposed. The correlation includes all tested variables in dimensionless form and is valid for low heat flux, i.e., below 100 kW/m2.

Nanofluids for power engineering: Emergency cooling of overheated heat transfer surfaces

NASA Astrophysics Data System (ADS)

Bondarenko, B. I.; Moraru, V. N.; Sidorenko, S. V.; Komysh, D. V.

2016-07-01

The possibility of emergency cooling of an overheated heat transfer surface using nanofluids in the case of a boiling crisis is explored by means of synchronous recording of changes of main heat transfer parameters of boiling water over time. Two nanofluids are tested, which are derived from a mixture of natural aluminosilicates (AlSi-7) and titanium dioxide (NF-8). It is found that the introduction of a small portions of nanofluid into a boiling coolant (distilled water) in a state of film boiling ( t heater > 500°C) can dramatically decrease the heat transfer surface temperature to 130-150°C, which corresponds to a transition to a safe nucleate boiling regime without affecting the specific heat flux. The fact that this regime is kept for a long time at a specific heat load exceeding the critical heat flux for water and t heater = 125-130°C is particularly important. This makes it possible to prevent a potential accident emergency (heater burnout and failure of the heat exchanger) and to ensure the smooth operation of the equipment.

Verification of rapid method for estimation of added food colorant type in boiled sausages based on measurement of cross section color

NASA Astrophysics Data System (ADS)

Jovanović, J.; Petronijević, R. B.; Lukić, M.; Karan, D.; Parunović, N.; Branković-Lazić, I.

2017-09-01

During the previous development of a chemometric method for estimating the amount of added colorant in meat products, it was noticed that the natural colorant most commonly added to boiled sausages, E 120, has different CIE-LAB behavior compared to artificial colors that are used for the same purpose. This has opened the possibility of transforming the developed method into a method for identifying the addition of natural or synthetic colorants in boiled sausages based on the measurement of the color of the cross-section. After recalibration of the CIE-LAB method using linear discriminant analysis, verification was performed on 76 boiled sausages, of either frankfurters or Parisian sausage types. The accuracy and reliability of the classification was confirmed by comparison with the standard HPLC method. Results showed that the LDA + CIE-LAB method can be applied with high accuracy, 93.42 %, to estimate food color type in boiled sausages. Natural orange colors can give false positive results. Pigments from spice mixtures had no significant effect on CIE-LAB results.

Nucleate boiling performance on nano/microstructures with different wetting surfaces

PubMed Central

2012-01-01

A study of nucleate boiling phenomena on nano/microstructures is a very basic and useful study with a view to the potential application of modified surfaces as heating surfaces in a number of fields. We present a detailed study of boiling experiments on fabricated nano/microstructured surfaces used as heating surfaces under atmospheric conditions, employing identical nanostructures with two different wettabilities (silicon-oxidized and Teflon-coated). Consequently, enhancements of both boiling heat transfer (BHT) and critical heat flux (CHF) are demonstrated in the nano/microstructures, independent of their wettability. However, the increment of BHT and CHF on each of the different wetting surfaces depended on the wetting characteristics of heating surfaces. The effect of water penetration in the surface structures by capillary phenomena is suggested as a plausible mechanism for the enhanced CHF on the nano/microstructures regardless of the wettability of the surfaces in atmospheric condition. This is supported by comparing bubble shapes generated in actual boiling experiments and dynamic contact angles under atmospheric conditions on Teflon-coated nano/microstructured surfaces. PMID:22559173

Boiling enriches the linear polysulfides and the hydrogen sulfide-releasing activity of garlic.

PubMed

Tocmo, Restituto; Wu, Yuchen; Liang, Dong; Fogliano, Vincenzo; Huang, Dejian

2017-04-15

Garlic is rich in polysulfides, and some of them can be H 2 S donors. This study was conducted to explore the effect of cooking on garlic's organopolysulfides and H 2 S-releasing activity. Garlic bulbs were crushed and boiled for a period ranging from 3 to 30min and the solvent extracts were analyzed by GC-MS/FID and HPLC. A cell-based assay was used to measure the H 2 S-releasing activity of the extracts. Results showed that the amounts of allyl polysulfides increased in crushed garlic boiled for 6-10min; however, prolonging the thermal treatment to 20 or 30min decreased their concentrations. Data of the H 2 S-releasing activity, expressed as diallyl trisulfide equivalents (DATS-E), parallel this trend, being significantly higher at 6 and 10min boiling. Our results showed enhancement of H 2 S-releasing activity upon moderate boiling, suggesting that shorter cooking time may maximize its health benefits as a dietary source of natural H 2 S donors. Copyright © 2016 Elsevier Ltd. All rights reserved.

Preliminary design of flight hardware for two-phase fluid research

NASA Technical Reports Server (NTRS)

Hustvedt, D. C.; Oonk, R. L.

1982-01-01

This study defined the preliminary designs of flight software for the Space Shuttle Orbiter for three two-phase fluid research experiments: (1) liquid reorientation - to study the motion of liquid in tanks subjected to small accelerations; (2) pool boiling - to study low-gravity boiling from horizontal cylinders; and (3) flow boiling - to study low-gravity forced flow boiling heat transfer and flow phenomena in a heated horizontal tube. The study consisted of eight major tasks: reassessment of the existing experiment designs, assessment of the Spacelab facility approach, assessment of the individual carry-on approach, selection of the preferred approach, preliminary design of flight hardware, safety analysis, preparation of a development plan, estimates of detailed design, fabrication and ground testing costs. The most cost effective design approach for the experiments is individual carry-ons in the Orbiter middeck. The experiments were designed to fit into one or two middeck lockers. Development schedules for the detailed design, fabrication and ground testing ranged from 15 1/2 to 18 months. Minimum costs (in 1981 dollars) ranged from $463K for the liquid reorientation experiment to $998K for the pool boiling experiment.

Investigation into flow boiling heat transfer in a minichannel with enhanced heating surface

NASA Astrophysics Data System (ADS)

Piasecka, Magdalena

2012-04-01

The paper presents results of flow boiling in a minichannel of 1.0 mm depth. The heating element for the working fluid (FC-72) that flows along the minichannel is a single-sided enhanced alloy foil made from Haynes-230. Microrecesses were formed on the selected area of the heating foil by laser technology. The observations of the flow structure were carried out through a piece of glass. Simultaneously, owing to the liquid crystal layer placed on the opposite side of the enhanced foil surface, it was possible to measure temperature distribution on the heating wall through another piece of glass. The experimental research has been focused on the transition from single phase forced convection to nucleate boiling, i.e. the zone of boiling incipience and further development of boiling. The objective of the paper is determining of the void fraction for some cross-sections of selected images for increasing heat fluxes supplied to the heating surface. The flow structure photos were processed in Corel graphics software and binarized. The analysis of phase volumes was developed in Techystem Globe software.

Effect of boiling, frying, and baking on recovery of aflatoxin from naturally contaminated corn grits or cornmeal.

PubMed

Stoloff, L; Trucksess, M W

1981-05-01

Corn grits naturally contaminated with aflatoxins were used for making boiled grits, and portions of the boiled grits were used for making pan-fried grits; cornmeal naturally contaminated with aflatoxins was used for making corn muffins. Procedures and recipes were derived from cookbook and market package recommendations. From analyses of the products for aflatoxins before and after preparation of the table-ready products, it was determined that 72 +/- 9% (n = 15) of the aflatoxin found in the original grits could be recovered after the grits were boiled. The recovery of aflatoxin B1 after the grits were fried was either 66 +/- 10% (n = 6) or 47 +/- 8% (n = 9), depending on whether 3 cups of water or 4 cups of water per cup of grits, respectively, were used for preparing the boiled grits before frying. Similarly, it was determined that 87 +/- 4% (n = 9) of the aflatoxin B1 found in the original cornmeal could be recovered from the baked muffins. No detectable aflatoxin B2 a was present in the extracts from any of the table-ready products.

Heat transfer and structure of flow at boiling of refrigerant R134a in channels with inserts in the form of finned twisted tape

NASA Astrophysics Data System (ADS)

Shishkin, A. V.; Tarasevich, S. E.

2018-03-01

The paper presents the results of experimental study of heat transfer for the refrigerant R134a flow in the channels with finned twisted tape inserts at bubble boiling. The flow regimes implemented under the given conditions are shown. The stable cord-like flows appear at boiling in channels with twisted tape inserts and high vapor content when the liquid phase moves in the form of a stream (cord) along the central part of the tape, which is not an active heat exchange surface. At boiling this can lead to an increase in the length required for complete liquid evaporation. Existing geometric modifications of twisted tapes are used in the heat-exchange equipment at forced convection of the coolant and do not solve the problem of cord-like flows elimination. The present work discusses the experimental study of heat transfer at boiling of refrigerant R134a in the channels with twisted tape inserts that have fins on its surface.

Recent Work on Flow Boiling and Condensation in a Single Microchannel

NASA Astrophysics Data System (ADS)

Quan, Xiaojun; Wang, Guodong; Cheng, Ping; Wu, Huiying

2007-06-01

Recent visualization and measurements results on flow boiling of water and condensation of steam in a single microchannel, carried out at Shanghai Jiaotong University, is summarized in this paper. For flow boiling of water, experiments were conducted in a single microchannel with a trapezoidal cross-section having a hydraulic diameter of 186 μm and a length of 30 mm. A boiling flow pattern map in terms of heat flux versus mass flux, showing the unstable and stable boiling flow regimes in the microchannel, is obtained. For the investigation of condensation, experiments were carried out for steam condensing inside a single microchannel with a length of 60mm having a hydraulic diameter of 87 μm and 120μm respectively. The location of transition from annular flow to plug/slug flow in a microchannel is found to be dependent on both the dimensionless condensation heat transfer rate as well as the Reynolds number of the steam. The frequency for the occurrence of the injection flow is found to increase with the increasing mass flux.

A study of boiling heat transfer as applied to the cooling of ball bearings in the high pressure oxygen turbopump of the space shuttle main engine

NASA Technical Reports Server (NTRS)

Schreiber, Will

1986-01-01

Two sets of ball bearings support the main shaft within the High Pressure Oxygen Turbopump (HPOTP) in the Space Shuttle Main Engine (SSME). In operation, these bearings are cooled and lubricated with high pressure liquid oxygen (LOX) flowing axially through the bearing assembly. Currently, modifications in the assembly design are being contemplated in order to enhance the lifetime of the bearings and to allow the HPOTP to operate under larger loads. An understanding of the fluid dynamics and heat transfer characteristics of the flowing LOX is necessary for the implementation of these design changes. The proposed computational model of the LOX fluid dynamics, in addition to dealing with a turbulent flow in a complex geometry, must address the complication associated with boiling and two-phase flow. The feasibility of and possible methods for modeling boiling heat transfer are considered. The theory of boiling as pertains to this particular problem is reviewed. Recommendations are given for experiments which would be necessary to establish validity for correlations needed to model boiling.

Consumers' perception and acceptance of boiled and fermented sausages from strongly boar tainted meat.

PubMed

Meier-Dinkel, Lisa; Gertheiss, Jan; Schnäckel, Wolfram; Mörlein, Daniel

2016-08-01

Characteristic off-flavours may occur in uncastrated male pigs depending on the accumulation of androstenone and skatole. Feasible processing of strongly tainted carcasses is challenging but gains in importance due to the European ban on piglet castration in 2018. This paper investigates consumers' acceptability of two sausage types: (a) emulsion-type (BOILED) and (b) smoked raw-fermented (FERM). Liking (9 point scales) and flavour perception (check-all-that-apply with both, typical and negatively connoted sensory terms) were evaluated by 120 consumers (within-subject design). Proportion of tainted boar meat (0, 50, 100%) affected overall liking of BOILED, F (2, 238)=23.22, P<.001, but not of FERM sausages, F (2, 238)=0.89, P=.414. Consumers described the flavour of BOILED-100 as strong and sweaty. In conclusion, FERM products seem promising for processing of tainted carcasses whereas formulations must be optimized for BOILED in order to eliminate perceptible off-flavours. Boar taint rejection thresholds may be higher for processed than those suggested for unprocessed meat cuts. Copyright © 2016 Elsevier Ltd. All rights reserved.

Minimizing corrosion in coal liquid distillation

DOEpatents

Baumert, Kenneth L.; Sagues, Alberto A.; Davis, Burtron H.

1985-01-01

In an atmospheric distillation tower of a coal liquefaction process, tower materials corrosion is reduced or eliminated by introduction of boiling point differentiated streams to boiling point differentiated tower regions.

Pad B Liquid Hydrogen Storage Tank

NASA Technical Reports Server (NTRS)

Hall, Felicia

2007-01-01

Kennedy Space Center is home to two liquid hydrogen storage tanks, one at each launch pad of Launch Complex 39. The liquid hydrogen storage tank at Launch Pad B has a significantly higher boil off rate that the liquid hydrogen storage tank at Launch Pad A. This research looks at various calculations concerning the at Launch Pad B in an attempt to develop a solution to the excess boil off rate. We will look at Perlite levels inside the tank, Boil off rates, conductive heat transfer, and radiant heat transfer through the tank. As a conclusion to the research, we will model the effects of placing an external insulation to the tank in order to reduce the boil off rate and increase the economic efficiency of the liquid hydrogen storage tanks.

Proposal of experimental setup on boiling two-phase flow on-orbit experiments onboard Japanese experiment module "KIBO"

NASA Astrophysics Data System (ADS)

Baba, S.; Sakai, T.; Sawada, K.; Kubota, C.; Wada, Y.; Shinmoto, Y.; Ohta, H.; Asano, H.; Kawanami, O.; Suzuki, K.; Imai, R.; Kawasaki, H.; Fujii, K.; Takayanagi, M.; Yoda, S.

2011-12-01

Boiling is one of the efficient modes of heat transfer due to phase change, and is regarded as promising means to be applied for the thermal management systems handling a large amount of waste heat under high heat flux. However, gravity effects on the two-phase flow phenomena and corresponding heat transfer characteristics have not been clarified in detail. The experiments onboard Japanese Experiment Module "KIBO" in International Space Station on boiling two-phase flow under microgravity conditions are proposed to clarify both of heat transfer and flow characteristics under microgravity conditions. To verify the feasibility of ISS experiments on boiling two-phase flow, the Bread Board Model is assembled and its performance and the function of components installed in a test loop are examined.

Enhancement of critical heat flux in nucleate boiling of nanofluids: a state-of-art review

PubMed Central

2011-01-01

Nanofluids (suspensions of nanometer-sized particles in base fluids) have recently been shown to have nucleate boiling critical heat flux (CHF) far superior to that of the pure base fluid. Over the past decade, numerous experimental and analytical studies on the nucleate boiling CHF of nanofluids have been conducted. The purpose of this article is to provide an exhaustive review of these studies. The characteristics of CHF enhancement in nanofluids are systemically presented according to the effects of the primary boiling parameters. Research efforts to identify the effects of nanoparticles underlying irregular enhancement phenomena of CHF in nanofluids are then presented. Also, attempts to explain the physical mechanism based on available CHF theories are described. Finally, future research needs are identified. PMID:21711949

Heat transfer enhancement at increasing water concentration in alcohol in the process of non-stationary film boiling

NASA Astrophysics Data System (ADS)

Kanin, P. K.; Ryazantsev, V. A.; Lexin, M. A.; Zabirov, A. R.; Yagov, V. V.

2018-03-01

New experimental data on heat transfer in pool film boiling of subcooled ethanol-water mixtures at spherical surfaces are considered. The water solutions with ethanol mass fraction from 10 to 91% and temperature of liquid 50°C were examined. All the experiments were conducted under atmospheric pressure, using the stainless steel sphere of 39 mm in diameter as a cooled body. The sphere was heated up to 450-750°C, depending on ethanol concentration, and immersed into the experimental vessel with subcooled mixture. As it is expected, boiling heat transfer intensifies with ethanol concentration decrease, and duration of cooling decreases. It means that stable film boiling duration decreases, and earlier transition to intensive heat transfer regime occurs.

Experimental realization of a CMOS-compatible optical directed priority encoder using cascaded micro-ring resonators

NASA Astrophysics Data System (ADS)

Xiao, Huifu; Li, Dezhao; Liu, Zilong; Han, Xu; Chen, Wenping; Zhao, Ting; Tian, Yonghui; Yang, Jianhong

2018-03-01

In this paper, we propose and experimentally demonstrate an integrated optical device that can implement the logical function of priority encoding from a 4-bit electrical signal to a 2-bit optical signal. For the proof of concept, the thermo-optic modulation scheme is adopted to tune each micro-ring resonator (MRR). A monochromatic light with the working wavelength is coupled into the input port of the device through a lensed fiber, and the four input electrical logic signals regarded as pending encode signals are applied to the micro-heaters above four MRRs to control the working states of the optical switches. The encoding results are directed to the output ports in the form of light. At last, the logical function of priority encoding with an operation speed of 10 Kbps is demonstrated successfully.

Wide-range and fast thermally-tunable silicon photonic microring resonators using the junction field effect

DOE PAGES

Wang, Xiaoxi; Lentine, Anthony; DeRose, Christopher; ...

2016-09-26

Tunable silicon microring resonators with small, integrated micro-heaters which exhibit a junction field effect were made using a conventional silicon-on-insulator (SOI) photonic foundry fabrication process. The design of the resistive tuning section in the microrings included a “pinched” p-n junction, which limited the current at higher voltages and inhibited damage even when driven by a pre-emphasized voltage waveform. Dual-ring filters were studied for both large (>4.9 THz) and small (850 GHz) free-spectral ranges. In conclusion, thermal red-shifting was demonstrated with microsecond-scale time constants, e.g., a dual-ring filter was tuned over 25 nm in 0.6 μs 10%–90% transition time, and withmore » efficiency of 3.2 μW/GHz.« less

Steady-state analytical model of suspended p-type 3C-SiC bridges under consideration of Joule heating

NASA Astrophysics Data System (ADS)

Balakrishnan, Vivekananthan; Dinh, Toan; Phan, Hoang-Phuong; Kozeki, Takahiro; Namazu, Takahiro; Viet Dao, Dzung; Nguyen, Nam-Trung

2017-07-01

This paper reports an analytical model and its validation for a released microscale heater made of 3C-SiC thin films. A model for the equivalent electrical and thermal parameters was developed for the two-layer multi-segment heat and electric conduction. The model is based on a 1D energy equation, which considers the temperature-dependent resistivity and allows for the prediction of voltage-current and power-current characteristics of the microheater. The steady-state analytical model was validated by experimental characterization. The results, in particular the nonlinearity caused by temperature dependency, are in good agreement. The low power consumption of the order of 0.18 mW at approximately 310 K indicates the potential use of the structure as thermal sensors in portable applications.

Extended and quasi-continuous tuning of quantum cascade lasers using superstructure gratings and integrated heaters

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

Bidaux, Yves, E-mail: yves.bidaux@alpeslasers.ch; Institute for Quantum Electronics, ETH-Zurich, CH-8093 Zurich; Bismuto, Alfredo, E-mail: alfredo.bismuto@alpeslasers.ch

2015-11-30

In this work, we demonstrate broad electrical tuning of quantum cascade lasers at 9.25 μm, 8.5 μm, and 4.4 μm in continuous wave operation using Vernier-effect distributed Bragg reflectors based on superstructure gratings. Integrated micro-heaters allow to switch from one Vernier channel to the other, while predictable and mode-hop free tuning can be obtained in each channel modulating the laser current with a side mode suppression ratio as high as 30 dB. The resulting device behaves effectively as a switchable multicolour tunable source. Tuning up to 6.5% of the central wavelength is observed. To prove the importance of the developed devices for high resolutionmore » molecular spectroscopy, a N{sub 2}O absorption spectrum has been measured.« less

Use of self-actuating and self-sensing cantilevers for imaging biological samples in fluid

PubMed Central

Barbero, R J; Deutschinger, A; Todorov, V; Gray, D S; Belcher, A M; Rangelow, I W; Youcef-Toumi, K

2014-01-01

In this paper, we present a detailed investigation into the suitability of atomic force microscopy (AFM) cantilevers with integrated deflection sensor and micro-actuator for imaging of soft biological samples in fluid. The Si cantilevers are actuated using a micro-heater at the bottom end of the cantilever. Sensing is achieved through p-doped resistors connected in a Wheatstone bridge. We investigated the influence of the water on the cantilever dynamics, the actuation and the sensing mechanisms, as well as the crosstalk between sensing and actuation. Successful imaging of yeast cells in water using the integrated sensor and actuator shows the potential of the combination of this actuation and sensing method. This constitutes a major step towards the automation and miniaturization required to establish AFM in routine biomedical diagnostics and in vivo applications. PMID:19801750

Boils

MedlinePlus

... boil is an infection that affects groups of hair follicles and nearby skin tissue. Related conditions include: Carbunculosis ... found on the skin's surface. Damage to the hair follicle allows the infection to grow deeper into the ...

CONTINUOUS ANALYZER UTILIZING BOILING POINT DETERMINATION

DOEpatents

Pappas, W.S.

1963-03-19

A device is designed for continuously determining the boiling point of a mixture of liquids. The device comprises a distillation chamber for boiling a liquid; outlet conduit means for maintaining the liquid contents of said chamber at a constant level; a reflux condenser mounted above said distillation chamber; means for continuously introducing an incoming liquid sample into said reflux condenser and into intimate contact with vapors refluxing within said condenser; and means for measuring the temperature of the liquid flowing through said distillation chamber. (AEC)

The Influences of Geologic Depositional Environments on Sand Boil Development, Tara Wildlife Lodge Area in Mississippi

DTIC Science & Technology

2016-03-01

ER D C/ G SL T R- 16 -7 The Influences of Geologic Depositional Environments on Sand Boil Development, Tara Wildlife Lodge Area in...client/default. ERDC/GSL TR-16-7 March 2016 The Influences of Geologic Depositional Environments on Sand Boil Development, Tara Wildlife Lodge...Army Corps of Engineers Washington, DC 20314-1000 ERDC/GSL TR-16-7 ii Abstract A comprehensive study of the subsurface geology in the Tara Wildlife

2005 Tri-Service Infrastructure Systems Conference and Exhibition. Volume 8, Track 8 Continued

DTIC Science & Technology

2005-08-04

Dennis Mekkers and Daniel M. Katz Current Research in Fate Current Research in Fate & Transport of Chemical and Biological Contaminants in Water...past boil activity, FSg = 1 • Minor boil or heavy seepage, FSg = 1.25 • Major boil activity, FSg = 1.5 The ratio 1:1.5 approximates (Critical State...prolonging life of road – SSB performed best under heavy traffic – If heavy traffic is possible, road should include a subbase Summary • Maintenance

Insulation of Nitrocellulose Boiling Tubs at Radford Army Ammunition Plant

DTIC Science & Technology

1982-03-01

control system. The amount of steam usea for the on-boil cycle with the single-sensor autocontrol averaged 647 kg/hr (1426 lb/hr) (test 1, table 2...This was a reduc- tion of 210 kg/hr (463 lb/hr) over the manually controlled uninsulated tub. Steam usage with the single sensor autocontrol and...uninsulated tub. At times durin)g the on- boil cycle of tests I and 2, the temperature of the manual sensor was different from the autocontrol sensor indicating

Boils and Carbuncles

MedlinePlus

... body. The spreading infection, commonly known as blood poisoning (sepsis), can lead to infections deep within your body, such as your heart (endocarditis) and bone (osteomyelitis). Prevention It's not always possible to prevent boils, especially ...

Nanoparticle coating of a microchannel surface is an effective method for increasing the critical heat flux

NASA Astrophysics Data System (ADS)

Shustov, M. V.; Kuzma-Kichta, Yu. A.; Lavrikov, A. V.

2017-04-01

Results are presented of an investigation into water boiling in a single microchannel 0.2 mm high, 3 mm wide, and 13.7 mm long with a smooth heating surface or with a coating from aluminum oxide nanoparticles. The experimental procedure and the test setup are described. The top wall of the microchannel is made of glass so that video recording in the reflected light of the process can be made. A coating of Al2O3 particles is applied onto the heating surface before the experiments using a method developed by the authors of the paper. The experiments yielded data on heat transfer and void fraction and its fluctuations for the bubble and transient boiling in the microchannel. The dependence was established of the heat flux on the temperature of the microchannel wall with a smooth surface or a surface with Al2O3 nanoparticle coating for various mass flows in the microchannel. The boiling crisis has been found to occur in the microchannel with a nanoparticle coating at a considerably higher heat flux than that in the channel without coating. The experimental data also suggest that the nanoparticle coating improves heat transfer in the transition boiling region. Processing of the data obtained using a high-speed video revealed void fraction fluctuations enabling us to describe two-phase flow regimes with the flow boiling in a microchannel. It has been found that a return flow occurs in the microchannel under certain conditions. A hypothesis for its causes is proposed. The dependence of the void fraction on the steam quality in the microchannel with or without a nanoparticle coating was determined from the video records. The experimental data on void fraction for boiling in the microchannel without coating are approximated by an empirical correlation. The experiments demonstrate that the void fraction during boiling in the microchannel with a nanoparticle coating is higher than during boiling in the channel without coating (where φ and x are the void fraction and the steam quality, respectively) in the region of a sharp increase in the φ( x) curve.

Sinus Rinsing and Neti Pots

MedlinePlus

... that it contains distilled or sterile water. 2. Filter (if boiled, sterile, or distilled water not available) ... if no boiled or distilled water and no filter available) Disinfect: Learn how to disinfect your water ...

Antioxidant capacity and fatty acids characterization of heat treated cow and buffalo milk.

PubMed

Khan, Imran Taj; Nadeem, Muhammad; Imran, Muhammad; Ayaz, Muhammad; Ajmal, Muhammad; Ellahi, Muhammad Yaqoob; Khalique, Anjum

2017-08-24

Antioxidant capacity of milk is largely due to vitamins A, E, carotenoids, zinc, selenium, superoxide dismutase, catalase, glutathione peroxidase and enzyme systems. Cow milk has antioxidant capacity while the antioxidant capacity of buffalo milk has been studied in a limited way. The information regarding the effect of pasteurization and boiling on antioxidant capacity of cow and buffalo milk is also scared. Cow and buffalo milk was exposed to two different heat treatments i.e. 65 °C for 30 min and boiling for 1 min. After heat treatments, milk samples were cooled down to 4 °C packaged in transparent 250 ml polyethylene PET bottles and stored at 4 °C for 6 days. Milk composition, total flavonoid content, total antioxidant capacity, reducing power, DPPH free radical scavenging activity, antioxidant activity in linoleic acid, vitamin C, A, E, selenium, Zinc, fatty acid profile, peroxide value and sensory characteristics were studied in raw, pasteurized and boiled cow and buffalo milk at 0, 3 and 6 days of storage period. Total antioxidant capacity (TAC) of raw, pasteurized and boiled milk for cow (42.1, 41.3 and 40.7%) and buffalo (58.4, 57.6 and 56.5%) samples was found, respectively. Reducing power (RP) of raw cow and buffalo milk was 6.74 and 13.7 while pasteurization and boiling did not showed significant effect on RP of both cow and buffalo milk. DPPH activity of raw, pasteurized and boiled milk for cow (24.3, 23.8 and 23.6%) and buffalo (31.8, 31.5 and 30.4%) samples was noted, respectively. Storage period up to 3 days was non-significant while DPPH assay after 6 days of storage period indicated significant decline in antioxidant activity of milk samples. Antioxidant activity in linoleic acid (AALA) of buffalo and cow milk were recorded 11.7 and 17.4%, respectively. Pasteurization and boiling did not showed any impact on antioxidant capacity of cow and buffalo milk. The Loss of vitamin C in pasteurization (40 and 42%) and boiling (82 and 61%) of cow and buffalo milk was recorded, respectively. Concentration of vitamin A and E in pasteurized cow and buffalo milk was not significantly different from raw milk samples of cow and buffalo. Concentration of selenium and zinc was not influenced by the heat treatment in both cow and buffalo milk samples. After 3 days of refrigerated storage, antioxidant capacity of both cow and buffalo milk decreased. Concentrations of short-chain and medium-chain fatty acids increased in pasteurized and boiled cow and buffalo milk, while long-chain fatty acids decreased in pasteurized and boiled cow and buffalo milk, with no effect on colour and flavor score. Peroxide value of pasteurized and boiled cow and buffalo milk was not influenced by the storage up to 3 days. These results suggest that buffalo milk had a higher antioxidant capacity than cow milk and pasteurized milk should be consumed within 3 days of refrigerated storage for better antioxidant perspectives.

Emergency Disinfection of Drinking Water

EPA Pesticide Factsheets

How to boil and disinfect water to kill most disease-causing microorganisms during emergency situations where regular water service has been interrupted and local authorities recommend using only bottled water, boiled water, or disinfected water.

46 CFR 154.707 - Cargo boil-off as fuel: Ventilation.

Code of Federal Regulations, 2011 CFR

2011-10-01

... SAFETY STANDARDS FOR SELF-PROPELLED VESSELS CARRYING BULK LIQUEFIED GASES Design, Construction and Equipment Cargo Pressure and Temperature Control § 154.707 Cargo boil-off as fuel: Ventilation. (a) A...

46 CFR 154.707 - Cargo boil-off as fuel: Ventilation.

Code of Federal Regulations, 2012 CFR

2012-10-01

... SAFETY STANDARDS FOR SELF-PROPELLED VESSELS CARRYING BULK LIQUEFIED GASES Design, Construction and Equipment Cargo Pressure and Temperature Control § 154.707 Cargo boil-off as fuel: Ventilation. (a) A...

46 CFR 154.707 - Cargo boil-off as fuel: Ventilation.

Code of Federal Regulations, 2010 CFR

2010-10-01

... SAFETY STANDARDS FOR SELF-PROPELLED VESSELS CARRYING BULK LIQUEFIED GASES Design, Construction and Equipment Cargo Pressure and Temperature Control § 154.707 Cargo boil-off as fuel: Ventilation. (a) A...

46 CFR 154.707 - Cargo boil-off as fuel: Ventilation.

Code of Federal Regulations, 2013 CFR

2013-10-01

... SAFETY STANDARDS FOR SELF-PROPELLED VESSELS CARRYING BULK LIQUEFIED GASES Design, Construction and Equipment Cargo Pressure and Temperature Control § 154.707 Cargo boil-off as fuel: Ventilation. (a) A...

46 CFR 154.707 - Cargo boil-off as fuel: Ventilation.

Code of Federal Regulations, 2014 CFR

2014-10-01

... SAFETY STANDARDS FOR SELF-PROPELLED VESSELS CARRYING BULK LIQUEFIED GASES Design, Construction and Equipment Cargo Pressure and Temperature Control § 154.707 Cargo boil-off as fuel: Ventilation. (a) A...

The initiation of boiling during pressure transients. [water boiling on metal surfaces

NASA Technical Reports Server (NTRS)

Weisman, J.; Bussell, G.; Jashnani, I. L.; Hsieh, T.

1973-01-01

The initiation of boiling of water on metal surfaces during pressure transients has been investigated. The data were obtained by a new technique in which light beam fluctuations and a pressure signal were simultaneously recorded on a dual beam oscilloscope. The results obtained agreed with those obtained using high speed photography. It was found that, for water temperatures between 90-150 C, the wall superheat required to initiate boiling during a rapid pressure transient was significantly higher than required when the pressure was slowly reduced. This result is explained by assuming that a finite time is necessary for vapor to fill the cavity at which the bubble originates. Experimental measurements of this time are in reasonably good agreement with calculations based on the proposed theory. The theory includes a new procedure for estimating the coefficient of vaporization.

Flow-Boiling Critical Heat Flux Experiments Performed in Reduced Gravity

NASA Technical Reports Server (NTRS)

Hasan, Mohammad M.; Mudawar, Issam

2005-01-01

Poor understanding of flow boiling in microgravity has recently emerged as a key obstacle to the development of many types of power generation and advanced life support systems intended for space exploration. The critical heat flux (CHF) is perhaps the most important thermal design parameter for boiling systems involving both heatflux-controlled devices and intense heat removal. Exceeding the CHF limit can lead to permanent damage, including physical burnout of the heat-dissipating device. The importance of the CHF limit creates an urgent need to develop predictive design tools to ensure both the safe and reliable operation of a two-phase thermal management system under the reduced-gravity (like that on the Moon and Mars) and microgravity environments of space. At present, very limited information is available on flow-boiling heat transfer and the CHF under these conditions.

Comparative Study of Raw and Boiled Silver Pomfret Fish from Coastal Area and Retail Market in Relation to Trace Metals and Proximate Composition

PubMed Central

Huque, Roksana; Munshi, M. Kamruzzaman; Khatun, Afifa; Islam, Mahfuza; Hossain, Afzal; Hossain, Arzina; Akter, Shirin; Kabir, Jamiul; Nahar Jolly, Yeasmin; Islam, Ashraful

2014-01-01

Trace metals concentration and proximate composition of raw and boiled silver pomfret (Pampus argenteus) from coastal area and retail market were determined to gain the knowledge of the risk and benefits associated with indiscriminate consumption of marine fishes. The effects of cooking (boiling) on trace metal and proximate composition of silver pomfret fish were also investigated. Trace element results were determined by the Energy Dispersive X-ray Fluorescence (EDXRF) Spectrometer wherein fish samples from both areas exceeded the standard limits set by FAO/WHO for manganese, lead, cadmiumm and chromium and boiling has no significant effects on these three metal concentrations. Long-term intake of these contaminated fish samples can pose a health risk to humans who consume them. PMID:26904650

Some investigations on the enhancement of boiling heat transfer from planer surface embedded with continuous open tunnels

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

Das, A.K.; Das, P.K.; Saha, P.

2010-11-15

Boiling heat transfer from a flat surface can be enhanced if continuous open tunnel type structures are embedded in it. Further, improvement of boiling heat transfer from such surfaces has been tried by two separate avenues. At first, inclined tunnels are embedded over the solid surface and an effort is made to optimize the tunnel inclination for boiling heat transfer. Surfaces are manufactured in house with four different inclinations of the tunnels with or without a reentrant circular pocket at the end of the tunnel. Experiments conducted in the nucleate boiling regime showed that 45 deg inclination of the tunnelsmore » for both with and without base geometry provides the highest heat transfer coefficient. Next, active fluid rotation was imposed to enhance the heat transfer from tunnel type surfaces with and without the base geometry. Rotational speed imparted by mechanical stirrer was varied over a wide range. It was observed that fluid rotation enhances the heat transfer coefficient only up to a certain value of stirrer speed. Rotational speed values, beyond this limit, reduce the boiling heat transfer severely. A comparison shows that embedding continuous tunnel turns out to be a better option for the increase of heat transfer coefficient compared to the imposition of fluid rotation. But the behavior of inclined tunnels under the action of fluid rotation is yet to be established and can be treated as a future scope of the work. (author)« less

Cryogenic thermal system analysis for orbital propellant depot

NASA Astrophysics Data System (ADS)

Chai, Patrick R.; Wilhite, Alan W.

2014-09-01

In any manned mission architecture, upwards of seventy percent of all payload delivered to orbit is propellant, and propellant mass fraction dominates almost all transportation segments of any mission requiring a heavy lift launch system like the Saturn V. To mitigate this, the use of an orbital propellant depot has been extensively studied. In this paper, a thermal model of an orbital propellant depot is used to examine the effects of passive and active thermal management strategies. Results show that an all passive thermal management strategy results in significant boil-off for both hydrogen and oxygen. At current launch vehicle prices, these boil-offs equate to millions of dollars lost per month. Zero boil-off of propellant is achievable with the use of active cryocoolers; however, the cooling power required to produce zero-boil-off is an order of magnitude higher than current state-of-the-art cryocoolers. This study shows a zero-boil-off cryocooler minimum power requirement of 80-100 W at 80 K for liquid oxygen, and 100-120 W at 20 K for liquid hydrogen for a representative Near-Earth Object mission. Research and development effort is required to improve the state-of-the-arts in-space cryogenic thermal management.

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.

Comparison of methods for extracting DNA from formalin-fixed paraffin sections for nonisotopic PCR.

PubMed

Frank, T S; Svoboda-Newman, S M; Hsi, E D

1996-09-01

DNA was extracted from unstained 5-microns sections of neutral buffered 10% formalin-fixed paraffin-embedded tissue by proteinase K digestion without detergents followed by boiling, proteinase K digestion with ionic detergents with and without phenol chloroform extraction and ethanol precipitation, sonication with proteinase K followed by boiling, or boiling alone. Serial 1:10 dilutions of the extracted DNA were subject to polymerase chain reaction (PCR) amplification of a 255-bp portion of the p53 gene. Digestion with proteinase K without ionic detergents followed by boiling (without phenol chloroform extraction) gave the best yield, enabling visualization of ethidium bromide-stained PCR product from a DNA dilution corresponding to 0.1 mm2 of tissue containing of the order of 10(3) nuclear profiles. Proteinase K digestion with detergents followed by phenol-chloroform extraction was no more effective than simple boiling. Although the success of PCR from preserved tissue will vary with the fixative and size of the amplified fragment, DNA extracted with this optimized method can be used for identification of viruses, loss of heterozygosity, and immunoglobulin gene rearrangements in paraffin-embedded tissue without radioisotopes.

Boiling point determination using adiabatic Gibbs ensemble Monte Carlo simulations: Application to metals described by embedded-atom potentials

NASA Astrophysics Data System (ADS)

Gelb, Lev D.; Chakraborty, Somendra Nath

2011-12-01

The normal boiling points are obtained for a series of metals as described by the "quantum-corrected Sutton Chen" (qSC) potentials [S.-N. Luo, T. J. Ahrens, T. Çağın, A. Strachan, W. A. Goddard III, and D. C. Swift, Phys. Rev. B 68, 134206 (2003)]. Instead of conventional Monte Carlo simulations in an isothermal or expanded ensemble, simulations were done in the constant-NPH adabatic variant of the Gibbs ensemble technique as proposed by Kristóf and Liszi [Chem. Phys. Lett. 261, 620 (1996)]. This simulation technique is shown to be a precise tool for direct calculation of boiling temperatures in high-boiling fluids, with results that are almost completely insensitive to system size or other arbitrary parameters as long as the potential truncation is handled correctly. Results obtained were validated using conventional NVT-Gibbs ensemble Monte Carlo simulations. The qSC predictions for boiling temperatures are found to be reasonably accurate, but substantially underestimate the enthalpies of vaporization in all cases. This appears to be largely due to the systematic overestimation of dimer binding energies by this family of potentials, which leads to an unsatisfactory description of the vapor phase.

Zero boil-off methods for large-scale liquid hydrogen tanks using integrated refrigeration and storage

NASA Astrophysics Data System (ADS)

Notardonato, W. U.; Swanger, A. M.; E Fesmire, J.; Jumper, K. M.; Johnson, W. L.; Tomsik, T. M.

2017-12-01

NASA has completed a series of tests at the Kennedy Space Center to demonstrate the capability of using integrated refrigeration and storage (IRAS) to remove energy from a liquid hydrogen (LH2) tank and control the state of the propellant. A primary test objective was the keeping and storing of the liquid in a zero boil-off state, so that the total heat leak entering the tank is removed by a cryogenic refrigerator with an internal heat exchanger. The LH2 is therefore stored and kept with zero losses for an indefinite period of time. The LH2 tank is a horizontal cylindrical geometry with a vacuum-jacketed, multilayer insulation system and a capacity of 125,000 liters. The closed-loop helium refrigeration system was a Linde LR1620 capable of 390W cooling at 20K (without any liquid nitrogen pre-cooling). Three different control methods were used to obtain zero boil-off: temperature control of the helium refrigerant, refrigerator control using the tank pressure sensor, and duty cycling (on/off) of the refrigerator as needed. Summarized are the IRAS design approach, zero boil-off control methods, and results of the series of zero boil-off tests.

Electrically Driven Liquid Film Boiling Experiment

NASA Technical Reports Server (NTRS)

Didion, Jeffrey R.

2016-01-01

This presentation presents the science background and ground based results that form the basis of the Electrically Driven Liquid Film Boiling Experiment. This is an ISS experiment that is manifested for 2021. Objective: Characterize the effects of gravity on the interaction of electric and flow fields in the presence of phase change specifically pertaining to: a) The effects of microgravity on the electrically generated two-phase flow. b) The effects of microgravity on electrically driven liquid film boiling (includes extreme heat fluxes). Electro-wetting of the boiling section will repel the bubbles away from the heated surface in microgravity environment. Relevance/Impact: Provides phenomenological foundation for the development of electric field based two-phase thermal management systems leveraging EHD, permitting optimization of heat transfer surface area to volume ratios as well as achievement of high heat transfer coefficients thus resulting in system mass and volume savings. EHD replaces buoyancy or flow driven bubble removal from heated surface. Development Approach: Conduct preliminary experiments in low gravity and ground-based facilities to refine technique and obtain preliminary data for model development. ISS environment required to characterize electro-wetting effect on nucleate boiling and CHF in the absence of gravity. Will operate in the FIR - designed for autonomous operation.

Zero Boil-Off Methods for Large Scale Liquid Hydrogen Tanks Using Integrated Refrigeration and Storage

NASA Technical Reports Server (NTRS)

Notardonato, W. U.; Swanger, A. M.; Fesmire, J. E.; Jumper, K. M.; Johnson, W. L.; Tomsik, T. M.

2017-01-01

NASA has completed a series of tests at the Kennedy Space Center to demonstrate the capability of using integrated refrigeration and storage (IRAS) to remove energy from a liquid hydrogen (LH2) tank and control the state of the propellant. A primary test objective was the keeping and storing of the liquid in a zero boil-off state, so that the total heat leak entering the tank is removed by a cryogenic refrigerator with an internal heat exchanger. The LH2 is therefore stored and kept with zero losses for an indefinite period of time. The LH2 tank is a horizontal cylindrical geometry with a vacuum-jacketed, multi-layer insulation system and a capacity of 125,000 liters. The closed-loop helium refrigeration system was a Linde LR1620 capable of 390W cooling at 20K (without any liquid nitrogen pre-cooling). Three different control methods were used to obtain zero boil-off: temperature control of the helium refrigerant, refrigerator control using the tank pressure sensor, and duty cycling (on/off) of the refrigerator as needed. Summarized are the IRAS design approach, zero boil-off control methods, and results of the series of zero boil-off tests.

Bubble Departure from Metal-Graphite Composite Surfaces and Its Effects on Pool Boiling Heat Transfer

NASA Technical Reports Server (NTRS)

Chao, David F.; Sankovic, John M.; Motil, Brian J.; Yang, W-J.; Zhang, Nengli

2010-01-01

The formation and growth processes of a bubble in the vicinity of graphite micro-fiber tips on metal-graphite composite boiling surfaces and their effects on boiling behavior are investigated. It is discovered that a large number of micro bubbles are formed first at the micro scratches and cavities on the metal matrix in pool boiling. By virtue of the non-wetting property of graphite, once the growing micro bubbles touch the graphite tips, the micro bubbles are sucked by the tips and merged into larger micro bubbles sitting on the end of the tips. The micro bubbles grow rapidly and coalesce to form macro bubbles, each spanning several tips. The necking process of a detaching macro bubble is analyzed. It is revealed that a liquid jet is produced by sudden break-off of the bubble throat. The composite surfaces not only have higher temperatures in micro- and macrolayers but also make higher frequency of the bubble departure, which increase the average heat fluxes in both the bubble growth stage and in the bubble departure period. Based on these analyses, the enhancement mechanism of pool boiling heat transfer on composite surfaces is clearly revealed.

1 H NMR-based water-soluble lower molecule characterization and fatty acid composition of boiled Wuding chicken during processing.

PubMed

Xiao, Zhichao; Luo, Yuting; Wang, Guiying; Ge, Changrong; Zhou, Guanghong; Zhang, Wangang; Liao, Guozhou

2018-06-13

Boiled Wuding chicken was produced using whole chicken by washing, boiling 1 h with salt, deep frying and boiling 2 h. The effect of process on the WLOM (water-soluble lower molecule) profiles of products was characterized using proton nuclear magnetic resonance spectroscopy ( 1 H-NMR) and fatty acid composition of products was analyzed using gas chromatography-mass spectrometry (GC-MS). The metabonome was dominated by 49 WLOM and 22 fatty acid compounds were detected. PC1 and PC2 explained a total of 93.4% and 3% of variance, respectively. Compared with control group, the total WLOM and fatty acid content of the chicken breast were significantly decreased in other three processing stages (P<0.05). Comprehensive multivariate data analysis showed significant differences about precursor substance between the different processing including creatine, lactate, creatinine, glucose, taurine, anserine and acetate (P<0.05). These results contribute to a more accurate understanding of precursor substance changes of flavor in chicken meat during processing. Boiled treated chicken had significant effects on fatty acid and WLOM compounds. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Kinetics-based phase change approach for VOF method applied to boiling flow

NASA Astrophysics Data System (ADS)

Cifani, Paolo; Geurts, Bernard; Kuerten, Hans

2014-11-01

Direct numerical simulations of boiling flows are performed to better understand the interaction of boiling phenomena with turbulence. The multiphase flow is simulated by solving a single set of equations for the whole flow field according to the one-fluid formulation, using a VOF interface capturing method. Interface terms, related to surface tension, interphase mass transfer and latent heat, are added at the phase boundary. The mass transfer rate across the interface is derived from kinetic theory and subsequently coupled with the continuum representation of the flow field. The numerical model was implemented in OpenFOAM and validated against 3 cases: evaporation of a spherical uniformly heated droplet, growth of a spherical bubble in a superheated liquid and two dimensional film boiling. The computational model will be used to investigate the change in turbulence intensity in a fully developed channel flow due to interaction with boiling heat and mass transfer. In particular, we will focus on the influence of the vapor bubble volume fraction on enhancing heat and mass transfer. Furthermore, we will investigate kinetic energy spectra in order to identify the dynamics associated with the wakes of vapor bubbles. Department of Applied Mathematics, 7500 AE Enschede, NL.

The effect of heating direction on flow boiling heat transfer of R134a in micro-channels

NASA Astrophysics Data System (ADS)

Xu, Mingchen; Jia, Li; Dang, Chao; Peng, Qi

2017-04-01

This paper presents effects of heating directions on heat transfer performance of R134a flow boiling in micro- channel heat sink. The heat sink has 30 parallel rectangular channels with cross-sectional dimensions of 500μm width 500μm depth and 30mm length. The experimental operation condition ranges of the heat flux and the mass flux were 13.48 to 82.25 W/cm2 and 373.3 to 1244.4 kg/m2s respectively. The vapor quality ranged from 0.07 to 0.93. The heat transfer coefficients of top heating and bottom heating both were up to 25 kW/m2 K. Two dominate transfer mechanisms of nucleate boiling and convection boiling were observed according to boiling curves. The experimental results indicated that the heat transfer coefficient of bottom heating was 13.9% higher than top heating in low heat flux, while in high heat flux, the heat transfer coefficient of bottom heating was 9.9%.higher than the top heating, because bubbles were harder to divorce the heating wall. And a modified correlation was provided to predict heat transfer of top heating.

BOILING HOUSE, INTERIOR, SECOND FLOOR, GARVER CLARIFIER IN FOREGROUND, TOPS ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

BOILING HOUSE, INTERIOR, SECOND FLOOR, GARVER CLARIFIER IN FOREGROUND, TOPS OF LONG TUBE EVAPORATORS IN BACKGROUND. VIEW FROM NORTHWEST - Kekaha Sugar Company, Sugar Mill Building, 8315 Kekaha Road, Kekaha, Kauai County, HI

A Study of Nucleate Boiling with Forced Convection in Microgravity

NASA Technical Reports Server (NTRS)

Merte, Herman, Jr.

1999-01-01

The ultimate objective of basic studies of flow boiling in microgravity is to improve the understanding of the processes involved, as manifested by the ability to predict its behavior. This is not yet the case for boiling heat transfer even in earth gravity, despite the considerable research activity over the past 30 years. The elements that constitute the nucleate boiling process - nucleation, growth, motion, and collapse of the vapor bubbles (if the bulk liquid is subcooled) - are common to both pool and flow boiling. It is well known that the imposition of bulk liquid motion affects the vapor bubble behavior relative to pool boiling, but does not appear to significantly influence the heat transfer. Indeed, it has been recommended in the past that empirical correlations or experimental data of pool boiling be used for design purposes with forced convection nucleate boiling. It is anticipated that such will most certainly not be possible for boiling in microgravity, based on observations made with pool boiling in microgravity. In earth gravity buoyancy will act to remove the vapor bubbles from the vicinity of the heater surface regardless of how much the imposed bulk velocity is reduced, depending, of course, on the geometry of the system. Vapor bubbles have been observed to dramatically increase in size in pool boiling in microgravity, and the heat flux at which dryout took place was reduced considerably below what is generally termed the critical heat flux (CHF) in earth gravity, depending on the bulk liquid subcooling. However, at heat flux levels below dryout, the nucleate pool boiling process was enhanced considerably over that in earth gravity, in spite of the large vapor bubbles formed in microgravity and perhaps as a consequence. These large vapor bubbles tended to remain in the vicinity of the heater surface, and the enhanced heat transfer appeared to be associated with the presence of what variously has been referred to as a liquid microlayer between the bubble and the heater surface. The enhancement of the boiling process with low velocities in earth gravity for those orientations producing the formation of a liquid macrolayer described above, accompanied by "sliding" vapor bubbles, has been demonstrated. The enhancement was presented as a function of orientation, subcooling, and heated length, while a criterion for the heat transfer for mixed natural/forced convection nucleate boiling was given previously. A major unknown in the prediction and application of flow boiling heat transfer in microgravity is the upper limit of the heat flux for the onset of dryout (or critical heat flux - CHF), for given conditions of fluid-heater surfaces, including geometry, system pressure and bulk liquid subcooling. It is clearly understood that the behavior in microgravity will be no different than on earth with sufficiently high flow velocities, and would require no space experimentation. However, the boundary at which this takes place is still an unknown. Previous results of CHF measurements were presented for low velocity flow boiling at various orientations in earth gravity as a function of flow velocity and bulk liquid subcooling, along with preliminary measurements of bubble residence times on a flat heater surface. This showed promise as a parameter to be used in modeling the CHF, both in earth gravity and in microgravity. The objective of the work here is to draw attention to and show results of current modeling efforts for the CHF, with low velocities in earth gravity at different orientations and subcoolings. Many geometrical possibilities for a heater surface exist in flowing boiling, with boiling on the inner and outer surfaces of tubes perhaps being the most common. If the vapor bubble residence time on and departure size from the heater surface bear a relationship to the CHF, as results to be given indicate, it is important that visualization of and access to vapor bubble growth be conveniently available for research purposes. In addition, it is desirable to reduce the number of variables as much as possible in a fundamental study. These considerations dictated the use of a flat heater surface, which is rectangular in shape, 1.91 cm by 3.81 cm (0.75 x 1.5 inches), consisting either of a 400 Angstrom thick semi-transparent gold film sputtered on a quartz substrate which serves simultaneously as a heater and a resistance thermometer, or a copper substrate of the same size. The heater substrate is a disc which can be rotated so that the heated length in the flow direction can be changed from 1.91 to 3.81 cm (0.75 to 1.5 inches). The fluid is R-113, and the velocities can be varied between 0.5 cm/s and 60 cm/s. For a sufficiently low velocity the CHF can be modeled reasonably well at various orientations by the correlation for pool boiling corrected for the influence of bulk liquid subcooling, multiplied by the square root of q, the angle relative to horizontal. This arises from equating buoyancy and drag forces in the inverted positions where the vapor bubbles are held against the heater surface as they slide. A distortion of the measurements relative to pool boiling occurs as the flow velocity increases. In modeling this effect at different levels of subcooling it appeared appropriate to estimate the volumetric rate of vapor generation, using measurements of bubble frequency (or residence time), void fraction and average bubble boundary layer thickness. These were determined with the use of a platinum hot wire probe 0.025 mm in diameter by 1.3 mm long, applying a constant current to distinguish between contact with liquid or vapor. Two-dimensional spatial variations are obtained with a special mechanism to resolve displacements in increments of 0.025 mm. From such measurements it was determined that the fraction of the surface heat transfer resulting in evaporation varies inversely with the subcooling correction factor for the CHF. The measured inverse bubble residence time is normalized relative to that predicted for an infinite horizontal flat plate at the CHF, and is correlated well with the CHF normalized relative to that for pool boiling, for various orientation angles and subcooling levels. This correspondence is then combined with a normalizing factor for the energy flux leaving the heater surface at the CHF and the computed bubble radius at departure, determined from the balance between the outward velocity of the interface due to evaporation and the buoyance induced velocity of the center of mass of the bubble. The product of the CHF and the corresponding residence time was determined to be a constant for all orientations at a given bulk flow velocity and liquid subcooling, and must be determined empirically for each velocity and subcooling at present. It then becomes possible to predict the CHF for the different orientations, velocities, and subcoolings. These are compared with normalized measurements of the CHF for velocities ranging from 4 cm/s to 55 cm/s, subcoolings from 2.8 to 22.2 K, over orientations angles of 360 degrees.

The sudden coalescene model of the boiling crisis

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

Carrica, P.M.; Clausse, A.

1995-09-01

A local two-phase flow integral model of nucleate boiling and crisis is presented. The model is based on average balances on a control volume, yielding to a set of three nonlinear differential equations for the local void fraction, bubble number density and velocity. Boiling crisis as critical heat flux is interpreted as a dynamic transition caused by the coalescence of bubbles near the heater. The theoretical dynamic model is compared with experimental results obtained for linear power ramps in a horizontal plate heater in R-113, showing an excellent qualitative agreement.

Preliminary design and hazards report. Boiling Reactor Experiment V (BORAX V)

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

Rice, R. E.

1960-02-01

The preliminary objectives of the proposed BORAX V program are to test nuclear superheating concepts and to advance the technology of boiling-water-reactor design by performing experiments which will improve the understanding of factors limiting the stability of boiling reactors at high power densities. The reactor vessel is a cylinder with ellipsoidal heads, made of carbon steel clad internally with stainless steel. Each of the three cores is 24 in. high and has an effective diameter of 39 in. This is a preliminary report. (W.D.M.)

The boiling point of stratospheric aerosols.

NASA Technical Reports Server (NTRS)

Rosen, J. M.

1971-01-01

A photoelectric particle counter was used for the measurement of aerosol boiling points. The operational principle involves raising the temperature of the aerosol by vigorously heating a portion of the intake tube. At or above the boiling point, the particles disintegrate rather quickly, and a noticeable effect on the size distribution and concentration is observed. Stratospheric aerosols appear to have the same volatility as a solution of 75% sulfuric acid. Chemical analysis of the aerosols indicates that there are other substances present, but that the sulfate radical is apparently the major constituent.

Carcinogenic N-nitro-dimethylamine from the reaction of the analgesic amidopyrine and nitrite extracted from foodstuffs.

PubMed

LaBar, J; Sander, J

1975-11-25

The reaction of the analgesic amidopyrine (100 mg) with nitrite extracted from cured meats and from spinach in varying degrees of spoilage was studied. Unde physiological conditions the carcinogenic dimethylnitrosamine was formed at milligram levels at nitrite concentrations as low as 4 mg (in 175 ml extracted from 100 g boiled ham). The rate of decrease in concentration in the human stomach after ingestion of amidopyrine and of nitrite contained in boiled ham or in a broth from boiled ham was also measured.

Coal liquefaction process

DOEpatents

Wright, Charles H.

1986-01-01

A process for the liquefaction of coal wherein raw feed coal is dissolved in recycle solvent with a slurry containing recycle coal minerals in the presence of added hydrogen at elevated temperature and pressure. The highest boiling distillable dissolved liquid fraction is obtained from a vacuum distillation zone and is entirely recycled to extinction. Lower boiling distillable dissolved liquid is removed in vapor phase from the dissolver zone and passed without purification and essentially without reduction in pressure to a catalytic hydrogenation zone where it is converted to an essentially colorless liquid product boiling in the transportation fuel range.

Henry`s law constant for selected volatile organic compounds in high-boiling oils

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

Poddar, T.K.; Sirkar, K.K.

Absorption systems are often used to remove and recover organic vapors from process air/gas streams. A high boiling and inert liquid like silicone oil is an excellent absorbent for volatile organic compounds in air. Henry`s law constants of four different volatile organic compounds, namely, acetone, methanol, methylene chloride, and toluene between air and high-boiling oils were determined experimentally by the headspace-GC technique over a temperature range. The Henry`s law constants were fitted as a function of temperature to an equation.

Large outbreaks of Clostridium perfringens food poisoning associated with the consumption of boiled salmon.

PubMed Central

Hewitt, J. H.; Begg, N.; Hewish, J.; Rawaf, S.; Stringer, M.; Theodore-Gandi, B.

1986-01-01

Five large outbreaks of food poisoning are described in which clinical, epidemiological or laboratory data indicated Clostridium perfringens as the causative organism. The foodstuff common to all incidents was boiled salmon served cold as an hors d 'oeuvre. In all cases the fish had been subject to a long period of cooling or storage between boiling and consumption. It is thought that multiplication of the organism occurred during this time. Recommendations are made for the avoidance of further similar incidents. PMID:2874173

23. RW Meyer Sugar Mill: 18761889. Boiling House Interior, 1878. ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

23. RW Meyer Sugar Mill: 1876-1889. Boiling House Interior, 1878. View: North Wall of boiling house. In the original structure the three windows on the right admitted light and air from the outside. A shed occupied the left side of the wall outside (hence no windows). in 1881 the construction of the cooling shed closed in the right three windows. The sorghum is in the foreground. The centrifugals are in the left rear. - R. W. Meyer Sugar Mill, State Route 47, Kualapuu, Maui County, HI

On Boiling of Crude Oil under Elevated Pressure

NASA Astrophysics Data System (ADS)

Pimenova, Anastasiya V.; Goldobin, Denis S.

2016-02-01

We construct a thermodynamic model for theoretical calculation of the boiling process of multicomponent mixtures of hydrocarbons (e.g., crude oil). The model governs kinetics of the mixture composition in the course of the distillation process along with the boiling temperature increase. The model heavily relies on the theory of dilute solutions of gases in liquids. Importantly, our results are applicable for modelling the process under elevated pressure (while the empiric models for oil cracking are not scalable to the case of extreme pressure), such as in an oil field heated by lava intrusions.

Enhanced boiling in microchannels due to recirculation induced by repeated saw-toothed cross-sectional geometry

NASA Astrophysics Data System (ADS)

Gao, Le; Bhavnani, Sushil H.

2017-10-01

A saw-toothed shaped microchannel heat sink is investigated for enhancing flow boiling heat transfer. Tests are conducted at mass fluxes of 444-1776 kg/m2 s and an inlet subcooling of 15 °C. The effects of channel geometry on boiling curves, flow patterns, pressure drops, and heat transfer coefficient are discussed in this letter. It is found that heat transfer performance is enhanced by up to 50% especially at heat flux levels associated with the current generation of microprocessors.

The effect of vapor polarity and boiling point on breakthrough for binary mixtures on respirator carbon.

PubMed

Robbins, C A; Breysse, P N

1996-08-01

This research evaluated the effect of the polarity of a second vapor on the adsorption of a polar and a nonpolar vapor using the Wheeler model. To examine the effect of polarity, it was also necessary to observe the effect of component boiling point. The 1% breakthrough time (1% tb), kinetic adsorption capacity (W(e)), and rate constant (kv) of the Wheeler model were determined for vapor challenges on carbon beds for both p-xylene and pyrrole (referred to as test vapors) individually, and in equimolar binary mixtures with the polar and nonpolar vapors toluene, p-fluorotoluene, o-dichlorobenzene, and p-dichlorobenzene (referred to as probe vapors). Probe vapor polarity (0 to 2.5 Debye) did not systematically alter the 1% tb, W(e), or kv of the test vapors. The 1% tb and W(e) for test vapors in binary mixtures can be estimated reasonably well, using the Wheeler model, from single-vapor data (1% tb +/- 30%, W(e) +/- 20%). The test vapor 1% tb depended mainly on total vapor concentration in both single and binary systems. W(e) was proportional to test vapor fractional molar concentration (mole fraction) in mixtures. The kv for p-xylene was significantly different (p < or = 0.001) when compared according to probe boiling point; however, these differences were apparently of limited importance in estimating 1% tb for the range of boiling points tested (111 to 180 degrees C). Although the polarity and boiling point of chemicals in the range tested are not practically important in predicting 1% tb with the Wheeler model, an effect due to probe boiling point is suggested, and tests with chemicals of more widely ranging boiling point are warranted. Since the 1% tb, and thus, respirator service life, depends mainly on total vapor concentration, these data underscore the importance of taking into account the presence of other vapors when estimating respirator service life for a vapor in a mixture.

Effect of boiling and roasting on the fermentation of soybeans into dawadawa (soy-dawadawa).

PubMed

Dakwa, Sarah; Sakyi-Dawson, Esther; Diako, Charles; Annan, Nana Takyiwa; Amoa-Awua, Wisdom Kofi

2005-09-25

Soybeans which had initially been dehulled by either boiling (boiled/dehulled) or roasting (roasted/dehulled) before peeling, were cooked and fermented into dawadawa, a traditional food condiment. The micropopulation, enzymatic activities, proximate composition, amino acid, and aroma profiles of the two types of soybean dawadawa were evaluated during fermentation. Only minor differences were found in the microbial profiles of the two types of soy-dawadawa. Although boiled/dehulled soy-dawadawa initially had lower microbial counts, it recorded higher counts at the advanced stages of fermentation. Proteolytic and amylolytic Bacillus species including Bacillus subtilis, Bacillus pumilus, Bacillus licheniformis, Bacillus cereus, and Bacillus firmus dominated the micropopulation of the two types of soy-dawadawa with Bacillus subtilis accounting for about 50% of the Bacillus species in all samples. Lactic acid bacteria and yeasts occurred in low numbers in the two types of soy-dawadawa. The proximate composition of the two types of soy-dawadawa were similar, and their contents of moisture and protein increased whilst fat and ash decreased during fermentation. Both types of fermenting soy-dawadawa recorded similar levels of alpha-amylase activity, but boiled/dehulled soy-dawadawa showed slightly higher protease activity. The levels of isoleucine, leucine, lysine, phenylalanine, arginine and proline increased significantly with fermentation time in both types of soy-dawadawa. With respect to differences in their aroma profiles, hexanodecanol, octadecyl acetate, 1,2-dimethyl benzene, tetradecene, (E)-5-eicosene, cyclohexadecane, and hexacosane were found only in the roasted/dehulled samples, whilst 1,2-ethanediol, ethyl acetate, dimethyl disulfide, cyclotetradecane, decene, indole , 2 butyl-octenal, acetophenone, and toluene were found only in the boiled/dehulled samples. A market focus group showed preference for roasted/dehulled soy-dawadawa over boiled/dehulled soy-dawadawa. Apart from the volatile aroma compounds, the biochemical and microbiological profiles of the two types of soy-dawadawa showed only minor differences and were also similar to the profiles reported for African locust bean dawadawa.

Design and test of a compact optics system for the pool boiling experiment

NASA Technical Reports Server (NTRS)

Ling, Jerri S.; Laubenthal, James R.

1990-01-01

The experiment described seeks to improve the understanding of the fundamental mechanisms that constitute nucleate pool boiling. The vehicle for accomplishing this is an investigation, including tests to be conducted in microgravity and coupled with appropriate analyses, of the heat transfer and vapor bubble dynamics associated with nucleation, bubble growth/collapse and subsequent motion, considering the interrelations between buoyancy, momentum and surface tension which will govern the motion of the vapor and surrounding liquid, as a function of the heating rate at the heat transfer surface and the temperature level and distribution in the bulk liquid. The experiment is designed to be contained within the confines of a Get-Away-Special Canister (GAS Can) installed in the bay of the space shuttle. When the shuttle reaches orbit, the experiment will be turned on and testing will proceed automatically. In the proposed Pool Boiling Experiment a pool of liquid, initially at a precisely defined pressure and temperature, will be subjected to a step imposed heat flux from a semitransparent thin-film heater forming part of one wall of the container such that boiling is initiated and maintained for a defined period of time at a constant pressure level. Transient measurements of the heater surface and fluid temperatures near the surface will be made, noting especially the conditions at the onset of boiling, along with motion photography of the boiling process in two simultaneous views, from beneath the heating surface and from the side. The conduct of the experiment and the data acquisition will be completely automated and self-contained. For the initial flight, a total of nine tests are proposed, with three levels of heat flux and three levels of subcooling. The design process used in the development and check-out of the compact photographic/optics system for the Pool Boiling Experiment is documented.

Effects of processing and cooking on the reduction of dinotefuran concentration in Japanese rice samples.

PubMed

Watanabe, Minae; Ueyama, Jun; Ueno, Eiji; Ueda, Yuko; Oda, Masaya; Umemura, Yuko; Tanahashi, Takashi; Ikai, Yoshitomo; Saito, Isao

2018-05-23

Dinotefuran is an insecticide belonging to the neonicotinoid class, which is frequently used to control pests in paddy rice owing to its permeability and effectiveness against sucking insects. Since 2002, this insecticide has been commercially available in Japan, and has become controversial due to its high detection frequency in brown rice for primary consumption. In this study, the effects of processing and cooking on the reduction of dinotefuran residues in commercially available brown rice were investigated. Boiled rice is difficult to homogenise and extract with acetonitrile. Using pre-freezing and cryogenic milling with powdered dry ice, dinotefuran in boiled rice was extracted well. A measurement method comprising sample preparation (acetonitrile extraction, gel permeation chromatography, and SPE) and detection with anLC-MS/MS system was used. In 10 out of 25 commercial brown rice samples, dinotefuran was detected at a concentration of 0.04 μg/g (mean), which was more than the limit of quantitation of 0.01 μg/g. The dinotefuran levels were significantly less than the MRL of 2 μg/g in Japan. Even after polishing, washing, and boiling, dinotefuran was detected in 10 brown rice samples, with mean residue levels of 74.7%, 60.8%, and 39.6%, respectively, of the original concentration in brown rice. Based on these data, the processing factor of dinotefuran in boiled rice has been estimated to be approximately 0.4. Dinotefuran residues were reduced in the boiled rice, but less so than other pesticides. Although the maximum daily intake of dinotefuran in boiled rice was 0.0065 mg/person/day, its percent ratio to the ADI of dinotefuran in Japan was less than 0.05%. These results suggest that the daily intake of dinotefuran from rice might not be a critical problem at present, in spite of its relatively high detection frequency in boiled rice.

Ground Water Rule - Boil Water Advisory - Public Notification Template

EPA Pesticide Factsheets

The Ground Water Rule - Boil Water Advisory - Public Notification Template can be use to issue a Tier 1 Public Notification when it has been determined that source ground water is contaminated with E. Coli bacteria.

BOILING HOUSE, INTERIOR, SECOND FLOOR, SYRUP TANKS IN RIGHT FOREGROUND, ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

BOILING HOUSE, INTERIOR, SECOND FLOOR, SYRUP TANKS IN RIGHT FOREGROUND, HIGH GRADE VACUUM PANS BEYOND THE SYRUP TANKS. VIEW FROM THE SOUTH - Kekaha Sugar Company, Sugar Mill Building, 8315 Kekaha Road, Kekaha, Kauai County, HI

Fecal contamination of drinking water within peri-urban households, Lima, Peru.

PubMed

Oswald, William E; Lescano, Andrés G; Bern, Caryn; Calderon, Maritza M; Cabrera, Lilia; Gilman, Robert H

2007-10-01

We assessed fecal contamination of drinking water in households in 2 peri-urban communities of Lima, Peru. We measured Escherichia coli counts in municipal source water and, within households, water from principal storage containers, stored boiled drinking water, and water in a serving cup. Source water was microbiologically clean, but 26 (28%) of 93 samples of water stored for cooking had fecal contamination. Twenty-seven (30%) of 91 stored boiled drinking water samples grew E. coli. Boiled water was more frequently contaminated when served in a drinking cup than when stored (P < 0.01). Post-source contamination increased successively through the steps of usage from source water to the point of consumption. Boiling failed to ensure safe drinking water at the point of consumption because of easily contaminated containers and poor domestic hygiene. Hygiene education, better point-of-use treatment and storage options, and in-house water connections are urgently needed.

Specific interface area and self-stirring in a two-liquid system experiencing intense interfacial boiling below the bulk boiling temperatures of both components

NASA Astrophysics Data System (ADS)

Goldobin, Denis S.; Pimenova, Anastasiya V.

2017-04-01

We present an approach to theoretical assessment of the mean specific interface area (δ S/δ V) for a well-stirred system of two immiscible liquids experiencing interfacial boiling. The assessment is based on the balance of transformations of mechanical energy and the laws of the momentum and heat transfer in the turbulent boundary layer. The theory yields relations between the specific interface area and the characteristics of the system state. In particular, this allows us to derive the equations of self-cooling dynamics of the system in the absence of external heat supply. The results provide possibility for constructing a self-contained mathematical description of the process of interfacial boiling. In this study, we assume the volume fractions of two components to be similar as well as the values of their kinematic viscosity and molecular heat diffusivity.

Thermal Design of Vapor Cooling of Flight Vehicle Structures Using LH2 Boil-Off

NASA Technical Reports Server (NTRS)

Wang, Xiao-Yen; Zoeckler, Joseph

2015-01-01

Using hydrogen boil-off vapor to cool the structure of a flight vehicle cryogenic upper stage can reduce heat loads to the stage and increase the usable propellant in the stage or extend the life of the stage. The hydrogen vapor can be used to absorb incoming heat as it increases in temperature before being vented overboard. In theory, the amount of heat leaking into the hydrogen tank from the structure will be reduced if the structure is cooled using the propellant boil-off vapor. However, the amount of boil-off vapor available to be used for cooling and the reduction in heat leak to the propellant tank are dependent to each other. The amount of heat leak reduction to the LH2 tank also depends on the total heat load on the stage and the vapor cooling configurations.

Investigation of HCl-based surface treatment for GaN devices

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

Okada, Hiroshi, E-mail: okada@ee.tut.ac.jp; Department of Electrical and Electronic Information Engineering, Toyohashi University of Technology, 1-1 Hibarigaoka, Tempaku-cho, Toyohashi 441-8580; Shinohara, Masatohi

2016-02-01

Surface treatments of GaN in HCl-based solutions are studied by X-ray photoelectron spectroscopy (XPS) and electrical characterization of fabricated GaN surfaces. A dilute-HCl treatment (HCl:H{sub 2}O=1:1) at room temperature and a boiled-HCl treatment (undiluted HCl) at 108°C are made on high-temperature annealed n-GaN. From the XPS study, removal of surface oxide by the dilute-HCl treatment was found, and more thoroughly oxide-removal was confirmed in the boiled-HCl treatment. Effect of the surface treatment on electrical characteristics on AlGaN/GaN transistor is also studied by applying treatment processes prior to the surface SiN deposition. Increase of drain current is found in boiled-HCl treatedmore » samples. The results suggest that the boiled-HCl treatment is effective for GaN device fabrication.« less

NUCLEAR SUPERHEATER FOR BOILING WATER REACTOR

DOEpatents

Holl, R.J.; Klecker, R.W.; Graham, C.B.

1962-05-15

A description is given of a boiling water reactor having a superheating region integral with the core. The core consists essentially of an annular boiling region surrounding an inner superheating region. Both regions contain fuel elements and are separated by a cylindrical wall, perforations being provided in the lower portion of the cylindrical wall to permit circulation of a common water moderator between the two regions. The superheater region comprises a plurality of tubular fuel assemblies through which the steam emanating from the boiling region passes to the steam outlet. Each superheater fuel assembly has an outer double-walled cylinder, the double walls being concentrically spaced and connected together at their upper ends but open at the bottom to provide for differential thermal expansion of the inner and outer walls. Gas is entrapped in the annulus between the walls which acts as an insulating space between the fissionable material inside and the moderator outside. (AEC)

Impact of boiling conditions on the molecular and sensory profile of a vegetable broth.

PubMed

Mougin, Alice; Mauroux, Olivier; Matthey-Doret, Walter; Barcos, Eugenia Maria; Beaud, Fernand; Bousbaine, Ahmed; Viton, Florian; Smarrito-Menozzi, Candice

2015-02-11

Low-pressure cooking has recently been identified as an alternative to ambient and high-pressure cooking to provide food with enhanced organoleptic properties. This work investigates the impact of the cooking process at different pressures on the molecular and sensory profile of a vegetable broth. Experimental results showed similar sensory and chemical profiles of vegetable broths when boiling at 0.93 and 1.5 bar, while an enhancement of sulfur volatile compounds correlated with a greater leek content and savory aroma was observed when boiling at low pressure (80 °C/0.48 bar). Thus, low-pressure cooking would allow preserving the most labile volatiles likely due to the lower water boiling temperature and the reduced level of oxygen. This study evidenced chemical and sensory impact of pressure during cooking and demonstrated that the flavor profile of culinary preparations can be enhanced by applying low-pressure conditions.

A PROCESS FOR SEPARATING AZEOTROPIC MIXTURES BY EXTRACTIVE AND CONVECTIVE DISTILLATION

DOEpatents

Frazer, J.W.

1961-12-19

A method is described for separating an azeotrope of carbon tetrachloride and 1,1,2,2-tetrafluorodinitroethane boiling at 60 deg C. The ndethod comnprises, specifically, feeding azeotrope vapors admixed with a non- reactive gas into an extractive distillation column heated to a temperature preferably somewhat above the boiling point of the constant boiling mixture. A solvent, di-n-butylphthalate, is metered into the column above the gas inlet and permitted to flow downward, earrying with it the higher bomling fraction, while the constituent having the lower boiling point passes out of the top of the column with the non-reactive gas and is collected in a nitrogen cold trap. Other solvents which alter the vapor pressure relationship may be substituted. The method is generally applicable to azeotropic mixtures. A number of specific mixtures whicb may be separated are disclosed. (AEC)

On mechanism of explosive boiling in nanosecond regime

NASA Astrophysics Data System (ADS)

Çelen, Serap

2016-06-01

Today laser-based machining is used to manufacture vital parts for biomedical, aviation and aerospace industries. The aim of the paper is to report theoretical, numerical and experimental investigations of explosive boiling under nanosecond pulsed ytterbium fiber laser irradiation. Experiments were performed in an effective peak power density range between 1397 and 1450 MW/cm2 on pure titanium specimens. The threshold laser fluence for phase explosion, the pressure and temperature at the target surface and the velocity of the expulsed material were reported. A narrow transition zone was realized between the normal vaporization and phase explosion fields. The proof of heterogeneous boiling was given with detailed micrographs. A novel thermal model was proposed for laser-induced splashing at high fluences. Packaging factor and scattering arc radius terms were proposed to state the level of the melt ejection process. Results of the present investigation explain the explosive boiling during high-power laser interaction with metal.

Energy-efficient drinking water disinfection for greenhouse gas mitigation

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

Gadgil, A.J.; Greene, D.M.; Rosenfeld, A.

Anecdotal evidence suggests that approximately one billion people worldwide use cookstoves to boil their drinking water. About half of this population is in China. Some populations (e.g. Jakarta) spend 1% of their GDP on boiling drinking water. Impoverished and/or ignorant populations not yet boiling their drinking water will do so when they can both afford it and understand the risks of unsafe drinking water. A recently developed water disinfection technology (UV Waterworks) can produce safe drinking water while earning tradable carbon credits (or credit as a clean development mechanism) when implemented as part of national energy, health, and carbon emissionsmore » trading policy, UV Waterworks uses approximately 6,000 times less energy than boiling over a biomass cookstove. Each unit that replaces boiling may save up to 175 or 300 tons/year of carbon-equivalent GHG emissions, depending on if it replaces sustainably harvested biomass (SHB) or non-SHB. For the approximately 500M Chinese boiling their drinking water over biomass (assumed SHB), this suggests a technical potential (that is, potential under the limiting case of 100% market adoption) of saving 87M tons/year of carbon-equivalent non-CO{sub 2} GHG emissions. The energy savings and corresponding emissions reductions will vary with cookstove fuels and stove efficiency: non-SHB and kerosene represent the most and least GHG-producing cookstove fuels, respectively, among those readily available to the populations of interest. The authors bracket the global technical potential for carbon emission reductions resulting from implementation of UV Waterworks, and estimate the value of tradable carbon credits earned from these reductions.« less

A geochemical model of the Platanares geothermal system, Honduras

USGS Publications Warehouse

Janik, C.J.; Truesdell, A.H.; Goff, F.; Shevenell, L.; Stallard, M.L.; Trujillo, P.E.; Counce, D.

1991-01-01

Results of exploration drilling combined with results of geologic, geophysical, and hydrogeochemical investigations have been used to construct a geochemical model of the Platanares geothermal system, Honduras. Three coreholes were drilled, two of which produced fluids from fractured Miocene andesite and altered Cretaceous to Eocene conglomerate at 450 to 680 m depth. Large volume artesian flows of 160-165??C, predominantly bicarbonate water are chemically similar to, but slightly less saline than widespread boiling hot-spring waters. The chemistry of the produced fluid is dominated by equilibrium reactions in sedimentary rocks at greater depths and higher temperatures than those measured in the wells. Chemical, isotope, and gas geothermometers indicate a deep fluid temperature of 200-245??C and reflect a relatively short residence time in the fractures feeding the wells. Chloride-enthalpy relations as well as isotopic and chemical compositions of well discharges, thermal springs, and local cold waters support a conceptual model of ascending high-temperature (minimum 225??C) parent fluid that has cooled conductively to form the 160-165??C shallow (to 680 m) fluid encountered by the wells. The hot-spring waters are formed by boiling and steam loss from more or less conductively cooled parent fluid. The more dilute boiling spring waters (Cl = ???32 mg/kg) have cooled from > 225??C to about 160??C by conduction and from 160??C to 98??C by boiling. The most concentrated boiling spring waters (Cl = 37 mg/kg) have cooled from > 225??C to about 200??C by conduction and from 200??C to 98??C by boiling. Intermediate concentrations reflect mixed cooling paths. ?? 1991.

Multiphysics modeling of two-phase film boiling within porous corrosion deposits

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

Jin, Miaomiao, E-mail: mmjin@mit.edu; Short, Michael, E-mail: hereiam@mit.edu

2016-07-01

Porous corrosion deposits on nuclear fuel cladding, known as CRUD, can cause multiple operational problems in light water reactors (LWRs). CRUD can cause accelerated corrosion of the fuel cladding, increase radiation fields and hence greater exposure risk to plant workers once activated, and induce a downward axial power shift causing an imbalance in core power distribution. In order to facilitate a better understanding of CRUD's effects, such as localized high cladding surface temperatures related to accelerated corrosion rates, we describe an improved, fully-coupled, multiphysics model to simulate heat transfer, chemical reactions and transport, and two-phase fluid flow within these deposits.more » Our new model features a reformed assumption of 2D, two-phase film boiling within the CRUD, correcting earlier models' assumptions of single-phase coolant flow with wick boiling under high heat fluxes. This model helps to better explain observed experimental values of the effective CRUD thermal conductivity. Finally, we propose a more complete set of boiling regimes, or a more detailed mechanism, to explain recent CRUD deposition experiments by suggesting the new concept of double dryout specifically in thick porous media with boiling chimneys. - Highlights: • A two-phase model of CRUD's effects on fuel cladding is developed and improved. • This model eliminates the formerly erroneous assumption of wick boiling. • Higher fuel cladding temperatures are predicted when accounting for two-phase flow. • Double-peaks in thermal conductivity vs. heat flux in experiments are explained. • A “double dryout” mechanism in CRUD is proposed based on the model and experiments.« less

Cryogenic Boil-Off Reduction System Testing

NASA Technical Reports Server (NTRS)

Plachta, David W.; Johnson, Wesley L.; Feller, Jeffrey R.

2014-01-01

Cryogenic propellants such as liquid hydrogen (LH2) and liquid oxygen (LO2) are a part of NASA's future space exploration due to the high specific impulse that can be achieved using engines suitable for moving 10's to 100's of metric tons of payload mass to destinations outside of low earth orbit. However, the low storage temperatures of LH2 and LO2 cause substantial boil-off losses for missions with durations greater than several days. The losses can be greatly reduced by incorporating high performance cryocooler technology to intercept heat load to the propellant tanks and by the integration of self-supporting multi-layer insulation. The active thermal control technology under development is the integration of the reverse turbo- Brayton cycle cryocooler to the propellant tank through a distributed cooling network of tubes coupled to a shield in the tank insulation and to the tank wall itself. Also, the self-supporting insulation technology was utilized under the shield to obtain needed tank applied LH2 performance. These elements were recently tested at NASA Glenn Research Center in a series of three tests, two that reduced LH2 boil-off and one to eliminate LO2 boil-off. This test series was conducted in a vacuum chamber that replicated the vacuum of space and the temperatures of low Earth orbit. The test results show that LH2 boil-off was reduced 60% by the cryocooler system operating at 90K and that robust LO2 zero boil-off storage, including full tank pressure control was achieved.

System of closing relations of a two-fluid model for the HYDRA-IBRAE/LM/V1 code for calculation of sodium boiling in channels of power equipment

NASA Astrophysics Data System (ADS)

Usov, E. V.; Butov, A. A.; Dugarov, G. A.; Kudasov, I. G.; Lezhnin, S. I.; Mosunova, N. A.; Pribaturin, N. A.

2017-07-01

The system of equations from a two-fluid model is widely used in modeling thermohydraulic processes during accidents in nuclear reactors. The model includes conservation equations governing the balance of mass, momentum, and energy in each phase of the coolant. The features of heat and mass transfer, as well as of mechanical interaction between phases or with the channel wall, are described by a system of closing relations. Properly verified foreign and Russian codes with a comprehensive system of closing relations are available to predict processes in water coolant. As to the sodium coolant, only a few open publications on this subject are known. A complete system of closing relations used in the HYDRA-IBRAE/LM/V1 thermohydraulic code for calculation of sodium boiling in channels of power equipment is presented. The selection of these relations is corroborated on the basis of results of analysis of available publications with an account taken of the processes occurring in liquid sodium. A comparison with approaches outlined in foreign publications is presented. Particular attention has been given to the calculation of the sodium two-phase flow boiling. The flow regime map and a procedure for the calculation of interfacial friction and heat transfer in a sodium flow with account taken of high conductivity of sodium are described in sufficient detail. Correlations are presented for calculation of heat transfer for a single-phase sodium flow, sodium flow boiling, and sodium flow boiling crisis. A method is proposed for prediction of flow boiling crisis initiation.

Pool boiling characteristics and critical heat flux mechanisms of microporous surfaces and enhancement through structural modification

NASA Astrophysics Data System (ADS)

Ha, Minseok; Graham, Samuel

2017-08-01

Experimental studies have shown that microporous surfaces induce one of the highest enhancements in critical heat flux (CHF) during pool boiling. However, microporous surfaces may also induce a very large surface superheat (>100 °C) which is not desirable for applications such as microelectronics cooling. While the understanding of the CHF mechanism is the key to enhancing boiling heat transfer, a comprehensive understanding is not yet available. So far, three different theories for the CHF of microporous surfaces have been suggested: viscous-capillary model, hydrodynamic instability model, and dryout of the porous coatings. In general, all three theories account for some aspects of boiling phenomena. In this study, the theories are examined through their correlations with experimental data on microporous surfaces during pool boiling using deionized (DI) water. It was found that the modulation of the vapor-jet through the pore network enables a higher CHF than that of a flat surface based on the hydrodynamic instability theory. In addition, it was found that as the heat flux increases, a vapor layer grows in the porous coatings described by a simple thermal resistance model which is responsible for the large surface superheat. Once the vapor layer grows to fill the microporous structure, transition to film boiling occurs and CHF is reached. By disrupting the formation of this vapor layer through the fabrication of channels to allow vapor escape, an enhancement in the CHF and heat transfer coefficient was observed, allowing CHF greater than 3500 kW/m2 at a superheat less than 50 °C.

Comparison of boiling and chlorination on the quality of stored drinking water and childhood diarrhoea in Indonesian households

PubMed Central

FAGERLI, K.; TRIVEDI, K. K.; SODHA, S. V.; BLANTON, E.; ATI, A.; NGUYEN, T.; DELEA, K. C.; AINSLIE, R.; FIGUEROA, M. E.; KIM, S.; QUICK, R.

2018-01-01

SUMMARY We compared the impact of a commercial chlorination product (brand name Air RahMat) in stored drinking water to traditional boiling practices in Indonesia. We conducted a baseline survey of all households with children <5 years in four communities, made 11 subsequent weekly home visits to assess acceptability and use of water treatment methods, measured Escherichia coli concentration in stored water, and determined diarrhoea prevalence among children <5 years. Of 281 households surveyed, boiling (83%) and Air RahMat (7%) were the principal water treatment methods. Multivariable log-binomial regression analyses showed lower risk of E. coli in stored water treated with Air RahMat than boiling (risk ratio (RR) 0·75, 95% confidence interval (CI) 0·56–1·00). The risk of diarrhoea in children <5 years was lower among households using Air RahMat (RR 0·43, 95% CI 0·19–0·97) than boiling, and higher in households with E. coli concentrations of 1–1000 MPN/100 ml (RR 1·54, 95% CI 1·04–2·28) or >1000 MPN/100 ml (RR 1·86, 95% CI 1·09–3·19) in stored water than in households without detectable E. coli. Although results suggested that Air RahMat water treatment was associated with lower E. coli contamination and diarrhoeal rates among children <5 years than water treatment by boiling, Air RahMat use remained low. PMID:28942755

Flow Boiling and Condensation Experiment (FBCE) for the International Space Station

NASA Technical Reports Server (NTRS)

Mudawar, Issam; Hasan, Mohammad M.; Kharangate, Chirag; O'Neill, Lucas; Konishi, Chris; Nahra, Henry; Hall, Nancy; Balasubramaniam, R.; Mackey, Jeffrey

2015-01-01

The proposed research aims to develop an integrated two-phase flow boiling/condensation facility for the International Space Station (ISS) to serve as primary platform for obtaining two-phase flow and heat transfer data in microgravity.

The Amateur Scientist.

ERIC Educational Resources Information Center

Walker, Jearl

1982-01-01

Discusses the thermodynamics of heating and boiling water, including the mechanics of bubble formation. Indicates that when salt was added to boiling water (when cooking pasta) the water temperature rose less than a degree, concluding that salt serves only as a seasoning. (Author/JN)

BOILING HOUSE, GROUND FLOOR. WAREHOUSE TO LEFT REAR, MASSECUITTE HEATERS ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

BOILING HOUSE, GROUND FLOOR. WAREHOUSE TO LEFT REAR, MASSECUITTE HEATERS ABOVE RIGHT, LOW GRADE CENTRIFUGALS BELOW. CRYSTALLIZER HOT WATER TANK TO REAR. VIEW FROM NORTHEAST - Lihue Plantation Company, Sugar Mill Building, Haleko Road, Lihue, Kauai County, HI

Microbiological Evaluation of Household Drinking Water Treatment in Rural China Shows Benefits of Electric Kettles: A Cross-Sectional Study

PubMed Central

Cohen, Alasdair; Tao, Yong; Luo, Qing; Zhong, Gemei; Romm, Jeff; Colford, John M.; Ray, Isha

2015-01-01

Background In rural China ~607 million people drink boiled water, yet little is known about prevailing household water treatment (HWT) methods or their effectiveness. Boiling, the most common HWT method globally, is microbiologically effective, but household air pollution (HAP) from burning solid fuels causes cardiovascular and respiratory disease, and black carbon emissions exacerbate climate change. Boiled water is also easily re-contaminated. Our study was designed to identify the HWT methods used in rural China and to evaluate their effectiveness. Methods We used a geographically stratified cross-sectional design in rural Guangxi Province to collect survey data from 450 households in the summer of 2013. Household drinking water samples were collected and assayed for Thermotolerant Coliforms (TTC), and physicochemical analyses were conducted for village drinking water sources. In the winter of 2013–2104, we surveyed 120 additional households and used remote sensors to corroborate self-reported boiling data. Findings Our HWT prevalence estimates were: 27.1% boiling with electric kettles, 20.3% boiling with pots, 34.4% purchasing bottled water, and 18.2% drinking untreated water (for these analyses we treated bottled water as a HWT method). Households using electric kettles had the lowest concentrations of TTC (73% lower than households drinking untreated water). Multilevel mixed-effects regression analyses showed that electric kettles were associated with the largest Log10TTC reduction (-0.60, p<0.001), followed by bottled water (-0.45, p<0.001) and pots (-0.44, p<0.01). Compared to households drinking untreated water, electric kettle users also had the lowest risk of having TTC detected in their drinking water (risk ratio, RR = 0.49, 0.34–0.70, p<0.001), followed by bottled water users (RR = 0.70, 0.53–0.93, p<0.05) and households boiling with pots (RR = 0.74, 0.54–1.02, p = 0.06). Conclusion As far as we are aware, this is the first HWT-focused study in China, and the first to quantify the comparative advantage of boiling with electric kettles over pots. Our results suggest that electric kettles could be used to rapidly expand safe drinking water access and reduce HAP exposure in rural China. PMID:26421716

Microbiological Evaluation of Household Drinking Water Treatment in Rural China Shows Benefits of Electric Kettles: A Cross-Sectional Study.

PubMed

Cohen, Alasdair; Tao, Yong; Luo, Qing; Zhong, Gemei; Romm, Jeff; Colford, John M; Ray, Isha

2015-01-01

In rural China ~607 million people drink boiled water, yet little is known about prevailing household water treatment (HWT) methods or their effectiveness. Boiling, the most common HWT method globally, is microbiologically effective, but household air pollution (HAP) from burning solid fuels causes cardiovascular and respiratory disease, and black carbon emissions exacerbate climate change. Boiled water is also easily re-contaminated. Our study was designed to identify the HWT methods used in rural China and to evaluate their effectiveness. We used a geographically stratified cross-sectional design in rural Guangxi Province to collect survey data from 450 households in the summer of 2013. Household drinking water samples were collected and assayed for Thermotolerant Coliforms (TTC), and physicochemical analyses were conducted for village drinking water sources. In the winter of 2013-2104, we surveyed 120 additional households and used remote sensors to corroborate self-reported boiling data. Our HWT prevalence estimates were: 27.1% boiling with electric kettles, 20.3% boiling with pots, 34.4% purchasing bottled water, and 18.2% drinking untreated water (for these analyses we treated bottled water as a HWT method). Households using electric kettles had the lowest concentrations of TTC (73% lower than households drinking untreated water). Multilevel mixed-effects regression analyses showed that electric kettles were associated with the largest Log10TTC reduction (-0.60, p<0.001), followed by bottled water (-0.45, p<0.001) and pots (-0.44, p<0.01). Compared to households drinking untreated water, electric kettle users also had the lowest risk of having TTC detected in their drinking water (risk ratio, RR = 0.49, 0.34-0.70, p<0.001), followed by bottled water users (RR = 0.70, 0.53-0.93, p<0.05) and households boiling with pots (RR = 0.74, 0.54-1.02, p = 0.06). As far as we are aware, this is the first HWT-focused study in China, and the first to quantify the comparative advantage of boiling with electric kettles over pots. Our results suggest that electric kettles could be used to rapidly expand safe drinking water access and reduce HAP exposure in rural China.

Experimental Investigation of Pool Boiling Heat Transfer Enhancement in Microgravity in the Presence of Electric Fields

NASA Technical Reports Server (NTRS)

Herman, Cila

1996-01-01

Boiling is an effective mode of heat transfer since high heat flux levels are possible driven by relatively small temperature differences. The high heat transfer coefficients associated with boiling have made the use of these processes increasingly attractive to aerospace engineering. Applications of this type include compact evaporators in the thermal control of aircraft avionics and spacecraft environments, heat pipes, and use of boiling to cool electronic equipment. In spite of its efficiency, cooling based on liquid-vapor phase change processes has not yet found wide application in aerospace engineering due to specific problems associated with the low gravity environment. After a heated surface has reached the superheat required for the initiation of nucleate boiling, bubbles will start forming at nucleation sites along the solid interface by evaporation of the liquid. Bubbles in contact with the wall will continue growing by this mechanism until they detach. In terrestrial conditions, bubble detachment is determined by the competition between body forces (e.g. buoyancy) and surface tension forces that act to anchor the bubble along the three phase contact line. For a given body force potential and a balance of tensions along the three phase contact line, bubbles must reach a critical size before the body force can cause them to detach from the wall. In a low gravity environment the critical bubble size for detachment is much larger than under terrestrial conditions, since buoyancy is a less effective means of bubble removal. Active techniques of heat transfer enhancement in single phase and phase change processes by utilizing electric fields have been the subject of intensive research during recent years. The field of electrohydrodynamics (EHD) deals with the interactions between electric fields, flow fields and temperature fields. Previous studies indicate that in terrestrial applications nucleate boiling heat transfer can be increased by a factor of 50 as compared to values obtained for the same system without electric fields. Imposing an external electric field holds the promise to improve pool boiling heat transfer in low gravity, since a phase separation force other than gravity is introduced. The goal of our research is to experimentally investigate the potential of EHD and the mechanisms responsible for EHD heat transfer enhancement in boiling in low gravity conditions.

Integration of P-CuO Thin Sputtered Layers onto Microsensor Platforms for Gas Sensing

PubMed Central

Presmanes, Lionel; Thimont, Yohann; el Younsi, Imane; Chapelle, Audrey; Blanc, Frédéric; Talhi, Chabane; Bonningue, Corine; Barnabé, Antoine; Menini, Philippe; Tailhades, Philippe

2017-01-01

P-type semiconducting copper oxide (CuO) thin films deposited by radio-frequency (RF) sputtering were integrated onto microsensors using classical photolithography technologies. The integration of the 50-nm-thick layer could be successfully carried out using the lift-off process. The microsensors were tested with variable thermal sequences under carbon monoxide (CO), ammonia (NH3), acetaldehyde (C2H4O), and nitrogen dioxide (NO2) which are among the main pollutant gases measured by metal-oxide (MOS) gas sensors for air quality control systems in automotive cabins. Because the microheaters were designed on a membrane, it was then possible to generate very rapid temperature variations (from room temperature to 550 °C in only 50 ms) and a rapid temperature cycling mode could be applied. This measurement mode allowed a significant improvement of the sensor response under 2 and 5 ppm of acetaldehyde. PMID:28621738

Demonstration of an optical directed half-subtracter using integrated silicon photonic circuits.

PubMed

Liu, Zilong; Zhao, Yongpeng; Xiao, Huifu; Deng, Lin; Meng, Yinghao; Guo, Xiaonan; Liu, Guipeng; Tian, Yonghui; Yang, Jianhong

2018-04-01

An integrated silicon photonic circuit consisting of two silicon microring resonators (MRRs) is proposed and experimentally demonstrated for the purpose of half-subtraction operation. The thermo-optic modulation scheme is employed to modulate the MRRs due to its relatively simple fabrication process. The high and low levels of the electrical pulse signal are utilized to define logic 1 and 0 in the electrical domain, respectively, and the high and low levels of the optical power represent logic 1 and 0 in the optical domain, respectively. Two electrical pulse sequences regarded as the operands are applied to the corresponding micro-heaters fabricated on the top of the MRRs to achieve their dynamic modulations. The final operation results of bit-wise borrow and difference are obtained at their corresponding output ports in the form of light. At last, the subtraction operation of two bits with the operation speed of 10 kbps is demonstrated successfully.

Characteristics of carbon nanotubes based micro-bubble generator for thermal jet printing.

PubMed

Zhou, Wenli; Li, Yupeng; Sun, Weijun; Wang, Yunbo; Zhu, Chao

2011-12-01

We propose a conceptional thermal printhead with dual microbubble generators mounted parallel in each nozzle chamber, where multiwalled carbon nanotubes are adopted as heating elements with much higher energy efficiency than traditional approaches using noble metals or polysilicon. Tailing effect of droplet can be excluded by appropriate control of grouped bubble generations. Characteristics of the corresponding micro-fabricated microbubble generators were comprehensively studied before the formation of printhead. Electrical properties of the microheaters on glass substrate in air and performance of bubble generation underwater focusing on the relationships between input power, device resistance and bubble behavior were probed. Proof-of-concept bubble generations grouped to eliminate the tailing effect of droplet were performed indicating precise pattern with high resolution could be realized by this kind of printhead. Experimental results revealed guidance to the geometric design of the printhead as well as its fabrication margin and the electrical control of the microbubble generators.

16 × 16 non-blocking silicon optical switch based on electro-optic Mach-Zehnder interferometers.

PubMed

Lu, Liangjun; Zhao, Shuoyi; Zhou, Linjie; Li, Dong; Li, Zuxiang; Wang, Minjuan; Li, Xinwan; Chen, Jianping

2016-05-02

We experimentally demonstrate a 16 × 16 non-blocking optical switch fabric with a footprint of 10.7 × 4.4 mm². The switch fabric is composed of 56 2 × 2 silicon Mach-Zehnder interferometers (MZIs), with each integrated with a pair of TiN resistive micro-heaters and a p-i-n diode. The average on-chip insertion loss at 1560 nm wavelength is ~6.7 dB and ~14 dB for the "all-cross" and "all-bar" states, respectively, with a loss variation of ± 1 dB over all routing paths. The measured rise/fall time of the switch upon electrical tuning is 3.2/2.5 ns. The switching functionality is verified by transmission of 20 Gb/s on-off keying (OOK) and 50 Gb/s quadrature phase-shift keying (QPSK) optical signals.

Aerogel Blanket Insulation Materials for Cryogenic Applications

NASA Technical Reports Server (NTRS)

Coffman, B. E.; Fesmire, J. E.; White, S.; Gould, G.; Augustynowicz, S.

2009-01-01

Aerogel blanket materials for use in thermal insulation systems are now commercially available and implemented by industry. Prototype aerogel blanket materials were presented at the Cryogenic Engineering Conference in 1997 and by 2004 had progressed to full commercial production by Aspen Aerogels. Today, this new technology material is providing superior energy efficiencies and enabling new design approaches for more cost effective cryogenic systems. Aerogel processing technology and methods are continuing to improve, offering a tailor-able array of product formulations for many different thermal and environmental requirements. Many different varieties and combinations of aerogel blankets have been characterized using insulation test cryostats at the Cryogenics Test Laboratory of NASA Kennedy Space Center. Detailed thermal conductivity data for a select group of materials are presented for engineering use. Heat transfer evaluations for the entire vacuum pressure range, including ambient conditions, are given. Examples of current cryogenic applications of aerogel blanket insulation are also given. KEYWORDS: Cryogenic tanks, thermal insulation, composite materials, aerogel, thermal conductivity, liquid nitrogen boil-off

Remarkable preservation of terpenoids and record of volatile signalling in plant-animal interactions from Miocene amber.

PubMed

Dutta, Suryendu; Mehrotra, Rakesh C; Paul, Swagata; Tiwari, R P; Bhattacharya, Sharmila; Srivastava, Gaurav; Ralte, V Z; Zoramthara, C

2017-09-08

Plants produce and release a large array of volatile organic compounds that play many ecological functions. These volatile plant metabolites serve as pollinator attractants, herbivore and pathogen repellents and protect plants from abiotic stresses. To date, the geological evolution of these organic compounds remains unknown. The preservation potential of these metabolites in the fossil record is very poor due to their low boiling points. Here we report a series of volatile sesquiterpenoids, including δ-elemene, α-copaene, β-elemene, β-caryophyllene, α-humulene, germacrene D, δ-cadiene and spathunenol, from early Miocene (~17 million year) amber from eastern India. The survival of these unaltered bioterpenoids can be attributed to the existence of extraordinary taphonomic conditions conducive to the preservation of volatile biomolecules through deep time. Furthermore, the occurrence of these volatiles in the early Miocene amber suggests that the plants from this period had evolved metabolic pathways to synthesize these organic molecules to play an active role in forest ecology, especially in plant-animal interactions.

Influence of culinary processing time on saffron's bioactive compounds (Crocus sativus L.).

PubMed

Rodríguez-Neira, Lidia; Lage-Yusty, María Asunción; López-Hernández, Julia

2014-12-01

Saffron, the dried stigmas of Crocus sativus L., is used as a condiment spice. The major bioactive compounds are crocins, picrocrocin and safranal, which are responsible for the sensory profile of saffron (color, flavor and aroma, respectively), and also health-promoting properties. In this paper, the effect on the bioactive compounds of different cooking times in boiling water at 100 °C in samples of Saffron from La Mancha (safranal, picrocrocin, trans-crocin 4, cis-crocin 4 and trans-crocin 3) was investigated. Performance characteristics of High Performance Liquid Chromatography with Variable Wavelength Detector method, parameters of linearity, limits of detection and quantification are reported. High Performance Liquid Chromatography-Photo Diode Array-Mass Spectrometry was used as a confirmatory technique in crocins identification. When the samples are subjected to different cooking times, they present different behaviors, depending on the bioactive compound. In this way, no changes were observed in the concentration of picrocrocin, while heat culinary treatment adversely affects the concentrations of crocins and safranal.

Coal liquefaction process

DOEpatents

Wright, C.H.

1986-02-11

A process is described for the liquefaction of coal wherein raw feed coal is dissolved in recycle solvent with a slurry containing recycle coal minerals in the presence of added hydrogen at elevated temperature and pressure. The highest boiling distillable dissolved liquid fraction is obtained from a vacuum distillation zone and is entirely recycled to extinction. Lower boiling distillable dissolved liquid is removed in vapor phase from the dissolver zone and passed without purification and essentially without reduction in pressure to a catalytic hydrogenation zone where it is converted to an essentially colorless liquid product boiling in the transportation fuel range. 1 fig.

Confinement by carbon nanotubes drastically alters the boiling and critical behavior of water droplets.

PubMed

Chaban, Vitaly V; Prezhdo, Victor V; Prezhdo, Oleg V

2012-03-27

Vapor pressure grows rapidly above the boiling temperature, and past the critical point liquid droplets disintegrate. Our atomistic simulations show that this sequence of events is reversed inside carbon nanotubes (CNT). Droplets disintegrate first and at low temperature, while pressure remains low. The droplet disintegration temperature is independent of the CNT diameter. In contrast, depending on CNT diameter, a temperature that is much higher than the bulk boiling temperature is required to raise the internal pressure. The control over pressure by CNT size can be useful for therapeutic drug delivery. © 2012 American Chemical Society

Zero Boil-OFF Tank Hardware Setup

NASA Image and Video Library

2017-09-19

iss053e027051 (Sept. 19, 2017) --- Flight Engineer Joe Acaba works in the U.S. Destiny laboratory module setting up hardware for the Zero Boil-Off Tank (ZBOT) experiment. ZBOT uses an experimental fluid to test active heat removal and forced jet mixing as alternative means for controlling tank pressure for volatile fluids. Rocket fuel, spacecraft heating and cooling systems, and sensitive scientific instruments rely on very cold cryogenic fluids. Heat from the environment around cryogenic tanks can cause their pressures to rise, which requires dumping or "boiling off" fluid to release the excess pressure, or actively cooling the tanks in some way.

Flexible Reactive Berm (FRBerm) for Removal of Heavy Metals from Runoff Water: ESTCP ER 1213 Treatability Study

DTIC Science & Technology

2016-06-01

occur during pre-treatment. Parameter measured Raw FB (B) Boiled FB (BB) Boiled and bleached FB (BBB) Boiled, bleached, and baked FB (BBBB...en t w ith a fi lte r s oc k fil le d w ith s an d am en de d w ith 1 5 pe rc en t T RA PP S™ . ERDC/EL TR-16-7 8 1.1.4 Model of TSS...the sand/amendments were removed from each column. Metal leaching following the treatments was measured using: • Toxicity Characteristic Leaching

Occurrence and potential causes of androgenic activities in source and drinking water in China.

PubMed

Hu, Xinxin; Shi, Wei; Wei, Si; Zhang, Xiaowei; Feng, Jianfang; Hu, Guanjiu; Chen, Sulan; Giesy, John P; Yu, Hongxia

2013-09-17

The increased incidences of disorders of male reproductive tract as well as testicular and prostate cancers have been attributed to androgenic pollutants in the environment. Drinking water is one pathway of exposure through which humans can be exposed. In this study, both potencies of androgen receptor (AR) agonists and antagonists were determined in organic extracts of raw source water as well as finished water from waterworks, tap water, boiled water, and poured boiled water in eastern China. Ten of 13 samples of source water exhibited detectable AR antagonistic potencies with AR antagonist equivalents (Ant-AR-EQs) ranging from <15.3 (detection limit) to 140 μg flutamide/L. However, no AR agonistic activity was detected in any source water. All finished water from waterworks, tap water, boiled water, and poured boiled water exhibited neither AR agonistic nor antagonistic activity. Although potential risks are posed by source water, water treatment processes effectively removed AR antagonists. Boiling and pouring of water further removed these pollutants. Phthalate esters (PAEs) including diisobutyl phthalate (DIBP) and dibutyl phthalate (DBP) were identified as major contributors to AR antagonistic potencies in source waters. Metabolites of PAEs exhibited no AR antagonistic activity and did not increase potencies of PAEs when they coexist.

ACE inhibition and antioxidant activity of different part of Channa striata prepared by various cooking method

NASA Astrophysics Data System (ADS)

Chasanah, E.; Budiari, S.; Thenawijaya, M.; Palupi, N. S.

2018-03-01

Channa striata (snakehead) extract has been known possessing positive activity, one of which is the ability to inhibit Angiotensin Converting Enzyme (ACE) activity in vitro. Aims of this study were to determine the effect of cooking and parts of C. striata, i.e. meat/fillet, gonad, skin, gill against the ACE inhibition activity and antioxidant activity in vitro. Heat processing methods used were direct boiling and indirect boiling and steamed at 100 °C for 10 min. ACE inhibition activity was analyzed using hippuryl-L-histidyl-L-leucine (HHL) as substrate and antioxidant activity was analyzed using DPPH method. The result shows that the higher the concentration of the extract (5 %, 20 %, 35 % and 50 %), the higher the antioxidant activity. The highest antioxidant activity was shown by gonad followed by meat extract, skin, and gill. Cooking treatment affected antioxidant activity, being the detrimental treatment were steam and direct boiling. The egg/gonad of C. striata showed the highest capability to inhibit ACE activity followed by meat/fillet, gill and skin. In concentration of 10 mg, extract of C. striata gonad was comparable to captopril, a commercial hypertension drug. While uncooked fillet showed the highest ACE inhibition activity followed by indirect boiling, direct boiling and steaming.

Magnetic resonance imaging of boiling induced by high intensity focused ultrasound

PubMed Central

Khokhlova, Tatiana D.; Canney, Michael S.; Lee, Donghoon; Marro, Kenneth I.; Crum, Lawrence A.; Khokhlova, Vera A.; Bailey, Michael R.

2009-01-01

Both mechanically induced acoustic cavitation and thermally induced boiling can occur during high intensity focused ultrasound (HIFU) medical therapy. The goal was to monitor the temperature as boiling was approached using magnetic resonance imaging (MRI). Tissue phantoms were heated for 20 s in a 4.7-T magnet using a 2-MHz HIFU source with an aperture and radius of curvature of 44 mm. The peak focal pressure was 27.5 MPa with corresponding beam width of 0.5 mm. The temperature measured in a single MRI voxel by water proton resonance frequency shift attained a maximum value of only 73 °C after 7 s of continuous HIFU exposure when boiling started. Boiling was detected by visual observation, by appearance on the MR images, and by a marked change in the HIFU source power. Nonlinear modeling of the acoustic field combined with a heat transfer equation predicted 100 °C after 7 s of exposure. Averaging of the calculated temperature field over the volume of the MRI voxel (0.3×0.5×2 mm3) yielded a maximum of 73 °C that agreed with the MR thermometry measurement. These results have implications for the use of MRI-determined temperature values to guide treatments with clinical HIFU systems. PMID:19354416

Boiling point determination using adiabatic Gibbs ensemble Monte Carlo simulations: application to metals described by embedded-atom potentials.

PubMed

Gelb, Lev D; Chakraborty, Somendra Nath

2011-12-14

The normal boiling points are obtained for a series of metals as described by the "quantum-corrected Sutton Chen" (qSC) potentials [S.-N. Luo, T. J. Ahrens, T. Çağın, A. Strachan, W. A. Goddard III, and D. C. Swift, Phys. Rev. B 68, 134206 (2003)]. Instead of conventional Monte Carlo simulations in an isothermal or expanded ensemble, simulations were done in the constant-NPH adabatic variant of the Gibbs ensemble technique as proposed by Kristóf and Liszi [Chem. Phys. Lett. 261, 620 (1996)]. This simulation technique is shown to be a precise tool for direct calculation of boiling temperatures in high-boiling fluids, with results that are almost completely insensitive to system size or other arbitrary parameters as long as the potential truncation is handled correctly. Results obtained were validated using conventional NVT-Gibbs ensemble Monte Carlo simulations. The qSC predictions for boiling temperatures are found to be reasonably accurate, but substantially underestimate the enthalpies of vaporization in all cases. This appears to be largely due to the systematic overestimation of dimer binding energies by this family of potentials, which leads to an unsatisfactory description of the vapor phase. © 2011 American Institute of Physics

Oceanographic effects of the 1992 Point Loma sewage pipe spill

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

Casey, R.; Ciccateri, A.; Dougherty, K.

Early in early 1992, 180 million gallons of advanced primarily treated sewage emptied into 10 meters of water from the broken Point Loma sewage pipe, San Diego. For about two months a sewage boil about the size of a football field existed at the surface and within the Point Loma kelp bed. Sampling and observations taken during the spill indicated the surface waters at the spill site were grayish and smelling of sewage. The sewage water had mixed with the marine waters reducing salinity to about one-half normal (or 15 ppt.). The sediment load of the sewage coated the bladesmore » of the giant kelp and the kelp was limp and withdrawn from the surface. At the site of the main boil the kelp appeared to have dropped to the bottom. Sediments on the bottom in the boil area were mainly coarse sands as compared to the surrounding sandy-muds. Preliminary results using laboratory analysis suggest: one month into the spill no infauna were observed in the sediments or planktons in the water of the boil area, but were in the surrounding sediments and water; the observed phytoplankton were dominated by dinoflagellates and suggested red tide conditions surrounding the boil. The site has been monitored monthly since the spill to observe further impact and recovery.« less

The Parable of the Boiled System Safety Professional: Drift to Failure

NASA Technical Reports Server (NTRS)

Shivers, C. Herbert

2011-01-01

Recall from the Parable of the Boiled Frog, that tossing a frog into boiling water causes the frog to jump out and hop away while placing a frog in suitable temperature water and slowly bringing the water to a boil results in the frog boiling due to not being aware of the slowly increasing danger, theoretically, of course. System safety professionals must guard against allowing dangers to creep unnoticed into their projects and be ever alert to notice signs of impending problems. People have used various phrases related to the idea, most notably, latent conditions, James Reason in Managing the Risks of Organizational Accidents (1, pp 10-11), Drift to Failure, Sydney Dekker (2, pp 82-86) in Resilience Engineering: Chronicling the Emergence of Confused Consensus in Resilience Engineering: Concepts and Precepts, Hollnagel, Woods and Leveson, and normalization of deviance, Diane Vaughan in The Challenger Launch Decision: Risky Technology, Culture, and Deviance at NASA (3). Reason also said, If eternal vigilance is the price of liberty, then chronic unease is the price of safety (1, p 37). Our challenge as system safety professionals is to be aware of the emergence of signals that warn us of slowly eroding safety margins. This paper will discuss how system safety professionals might better perform in that regard.

The effects of high-power microwaves on the ultrastructure of Bacillus subtilis.

PubMed

Kim, S-Y; Jo, E-K; Kim, H-J; Bai, K; Park, J-K

2008-07-01

To investigate the microbicidal mechanisms of high-power microwave (2.0 kW) irradiation on Bacillus subtilis and to determine the effect of this procedure on the ultrastructure of the cell wall. We performed viability test, examined cells using transmission electron microscopy (TEM), and measured the release of intracellular proteins and nucleic acids. The inactivation rate of B. subtilis by 2.0-kW microwave irradiation was higher than that of a domestic microwave (0.5 kW). Few proteins were released from either microwaved or boiled cells. However, the leakage of nucleic acids from 2.0-kW-microwaved cells was significantly higher than that of 0.5-kW-microwaved or boiled cells. Therefore, we examined ultrastructural alterations of microwaved or boiled cells to analyse the pattern of release of cytoplasmic contents. Although boiled cells did not show any ultrastructural changes on TEM, 2.0-kW-microwaved cells showed disruption of the cell wall. The microbicidal mechanisms of 2.0-kW microwave irradiation include damage to the microbial cell wall, breakage of the genomic DNA, and thermal coagulation of cytoplasmic proteins. TEM images showed that the cytoplasmic protein aggregation and cell envelope damage by microwave irradiation were different from the ultrastructural changes observed after boiling.

Method and apparatus for processing a test sample to concentrate an analyte in the sample from a solvent in the sample

DOEpatents

Turner, Terry D.; Beller, Laurence S.; Clark, Michael L.; Klingler, Kerry M.

1997-01-01

A method of processing a test sample to concentrate an analyte in the sample from a solvent in the sample includes: a) boiling the test sample containing the analyte and solvent in a boiling chamber to a temperature greater than or equal to the solvent boiling temperature and less than the analyte boiling temperature to form a rising sample vapor mixture; b) passing the sample vapor mixture from the boiling chamber to an elongated primary separation tube, the separation tube having internal sidewalls and a longitudinal axis, the longitudinal axis being angled between vertical and horizontal and thus having an upper region and a lower region; c) collecting the physically transported liquid analyte on the internal sidewalls of the separation tube; and d) flowing the collected analyte along the angled internal sidewalls of the separation tube to and pass the separation tube lower region. The invention also includes passing a turbulence inducing wave through a vapor mixture to separate physically transported liquid second material from vaporized first material. Apparatus are also disclosed for effecting separations. Further disclosed is a fluidically powered liquid test sample withdrawal apparatus for withdrawing a liquid test sample from a test sample container and for cleaning the test sample container.

Method and apparatus for processing a test sample to concentrate an analyte in the sample from a solvent in the sample

DOEpatents

Turner, T.D.; Beller, L.S.; Clark, M.L.; Klingler, K.M.

1997-10-14

A method of processing a test sample to concentrate an analyte in the sample from a solvent in the sample includes: (a) boiling the test sample containing the analyte and solvent in a boiling chamber to a temperature greater than or equal to the solvent boiling temperature and less than the analyte boiling temperature to form a rising sample vapor mixture; (b) passing the sample vapor mixture from the boiling chamber to an elongated primary separation tube, the separation tube having internal sidewalls and a longitudinal axis, the longitudinal axis being angled between vertical and horizontal and thus having an upper region and a lower region; (c) collecting the physically transported liquid analyte on the internal sidewalls of the separation tube; and (d) flowing the collected analyte along the angled internal sidewalls of the separation tube to and pass the separation tube lower region. The invention also includes passing a turbulence inducing wave through a vapor mixture to separate physically transported liquid second material from vaporized first material. Apparatus is also disclosed for effecting separations. Further disclosed is a fluidically powered liquid test sample withdrawal apparatus for withdrawing a liquid test sample from a test sample container and for cleaning the test sample container. 8 figs.

Rapid Evaporation of microbubbles

NASA Astrophysics Data System (ADS)

Gautam, Jitendra; Esmaeeli, Asghar

2008-11-01

When a liquid is heated to a temperature far above its boiling point, it evaporates abruptly. Boiling of liquid at high temperatures can be explosive and destructive, and poses a potential hazard for a host of industrial processes. Explosive boiling may occur if a cold and volatile liquid is brought into contact with a hot and non-volatile liquid, or if a liquid is superheated or depressurized rapidly. Such possibilities are realized, for example, in the depressurization of low boiling point liquefied natural gas (LNG) in the pipelines or storage tanks as a result of a leak. While boiling of highly heated liquids can be destructive at macroscale, the (nearly) instantaneous pace of the process and the release of large amount of kinetic energy make the phenomena extremely attractive at microscale where it is possible to utilize the released energy to derive micromechanical systems. For instance, there is currently a growing interest in micro-explosion of liquid for generation of micro bubbles for actuation purposes. The aim of the current study is to gain a fundamental understanding of the subject using direct numerical simulations. In particular, we seek to investigate the boundary between stable and unstable nucleus growth in terms of the degree of liquid superheat and to compare the dynamics of unstable and stable growth.

New Departure from Nucleate Boiling model relying on first principle energy balance at the boiling surface

NASA Astrophysics Data System (ADS)

Demarly, Etienne; Baglietto, Emilio

2017-11-01

Predictions of Departure from Nucleate Boiling have been a longstanding challenge when designing heat exchangers such as boilers or nuclear reactors. Many mechanistic models have been postulated over more than 50 years in order to explain this phenomenon but none is able to predict accurately the conditions which trigger the sudden change of heat transfer mode. This work aims at demonstrating the pertinence of a new approach for detecting DNB by leveraging recent experimental insights. The new model proposed departs from all the previous models by making the DNB inception come from an energy balance instability at the heating surface rather than a hydrodynamic instability of the bubbly layer above the surface (Zuber, 1959). The main idea is to modulate the amount of heat flux being exchanged via the nucleate boiling mechanism by the wetted area fraction on the surface, thus allowing a completely automatic trigger of DNB that doesn't require any parameter prescription. This approach is implemented as a surrogate model in MATLAB in order to validate the principles of the model in a simple and controlled geometry. Good agreement is found with the experimental data leveraged from the MIT Flow Boiling at various flow regimes. Consortium for Advanced Simulation of Light Water Reactors (CASL).

Effects of frying and boiling on the formation of heterocyclic amines in braised chicken.

PubMed

Yao, Y; Peng, Z Q; Shao, B; Wan, K H; Wang, F L; Zhang, Y W; Li, J K; Hui, T

2013-11-01

Braised chicken is a traditional ready-to-eat poultry product produced by frying chicken coated with maltose or honey and then boiling it in a soup that is circularly used. This study examined the effects of the frying time, honey concentration, boiling time, and cycle times of the soup on the formation of heterocyclic amines (HA), a class of mutagenic/carcinogenic compounds generated in heated muscle meat. Nine HA in chicken and recycled soups were analyzed by HPLC with UV and fluorescence detection. 1-Methyl-9H-pyrido[3,4-b]indole (Harman), 9H-pyrido[3,4-b]indole (Norharman), and 3-amino-1,4-dimethyl-5H-pyrido[4,3-b]indole (Trp-P-1) were detected in most samples, and the amount of each HA increased with the frying or boiling time. Chicken skin was found to have higher HA content than chicken meat. More HA were detected in the soup than in the chicken, in most cases. 2-Amino-3-methylimidazo[4,5-f]quinoline and 2-amino-3,4,8-trimethylimidazoquinoxaline (4,8-DiMeIQx) were also detected in chicken and soup circularly boiled 20 times, and the total amount of HA reached 68.80 and 96.98 ng/g in chicken and soup, respectively.

Numerical Investigation of Microgravity Tank Pressure Rise Due to Boiling

NASA Technical Reports Server (NTRS)

Hylton, Sonya; Ibrahim, Mounir; Kartuzova, Olga; Kassemi, Mohammad

2015-01-01

The ability to control self-pressurization in cryogenic storage tanks is essential for NASAs long-term space exploration missions. Predictions of the tank pressure rise in Space are needed in order to inform the microgravity design and optimization process. Due to the fact that natural convection is very weak in microgravity, heat leaks into the tank can create superheated regions in the liquid. The superheated regions can instigate microgravity boiling, giving rise to pressure spikes during self-pressurization. In this work, a CFD model is developed to predict the magnitude and duration of the microgravity pressure spikes. The model uses the Schrage equation to calculate the mass transfer, with a different accommodation coefficient for evaporation at the interface, condensation at the interface, and boiling in the bulk liquid. The implicit VOF model was used to account for the moving interface, with bounded second order time discretization. Validation of the models predictions was carried out using microgravity data from the Tank Pressure Control Experiment, which flew aboard the Space Shuttle Mission STS-52. Although this experiment was meant to study pressurization and pressure control, it underwent boiling during several tests. The pressure rise predicted by the CFD model compared well with the experimental data. The ZBOT microgravity experiment is scheduled to fly on February 2016 aboard the ISS. The CFD model was also used to perform simulations for setting parametric limits for the Zero-Boil-Off Tank (ZBOT) Experiments Test Matrix in an attempt to avoid boiling in the majority of the test runs that are aimed to study pressure increase rates during self-pressurization. *Supported in part by NASA ISS Physical Sciences Research Program, NASA HQ, USA

Comparison of vapor formation of water at the solid/water interface to colloidal solutions using optically excited gold nanostructures.

PubMed

Baral, Susil; Green, Andrew J; Livshits, Maksim Y; Govorov, Alexander O; Richardson, Hugh H

2014-02-25

The phase transformation properties of liquid water to vapor is characterized by optical excitation of the lithographically fabricated single gold nanowrenches and contrasted to the phase transformation properties of gold nanoparticles located and optically excited in a bulk solution system [two and three dimensions]. The 532 nm continuous wave excitation of a single gold nanowrench results in superheating of the water to the spinodal decomposition temperature of 580 ± 20 K with bubble formation below the spinodal decomposition temperature being a rare event. Between the spinodal decomposition temperature and the boiling point liquid water is trapped into a metastable state because a barrier to vapor nucleation exists that must be overcome before the thermodynamically stable state is realized. The phase transformation for an optically heated single gold nanowrench is different from the phase transformation of optically excited colloidal gold nanoparticles solution where collective heating effects dominates and leads to the boiling of the solution exactly at the boiling point. In the solution case, the optically excited ensemble of nanoparticles collectively raises the ambient temperature of water to the boiling point where liquid is converted into vapor. The striking difference in the boiling properties of the single gold nanowrench and the nanoparticle solution system can be explained in terms of the vapor-nucleation mechanism, the volume of the overheated liquid, and the collective heating effect. The interpretation of the observed regimes of heating and vaporization is consistent with our theoretical modeling. In particular, we explain with our theory why the boiling with the collective heating in a solution requires 3 orders of magnitude less intensity compared to the case of optically driven single nanowrench.

Phase relations and adiabats in boiling seafloor geothermal systems

USGS Publications Warehouse

Bischoff, J.L.; Pitzer, Kenneth S.

1985-01-01

Observations of large salinity variations and vent temperatures in the range of 380-400??C suggest that boiling or two-phase separation may be occurring in some seafloor geothermal systems. Consideration of flow rates and the relatively small differences in density between vapors and liquids at the supercritical pressures at depth in these systems suggests that boiling is occurring under closed-system conditions. Salinity and temperature of boiling vents can be used to estimate the pressure-temperature point in the subsurface at which liquid seawater first reached the two-phase boundary. Data are reviewed to construct phase diagrams of coexisting brines and vapors in the two-phase region at pressures corresponding to those of the seafloor geothermal systems. A method is developed for calculating the enthalpy and entropy of the coexisting mixtures, and results are used to construct adiabats from the seafloor to the P-T two-phase boundary. Results for seafloor vents discharging at 2300 m below sea level indicate that a 385??C vent is composed of a brine (7% NaCl equivalent) in equilibrium with a vapor (0.1% NaCl). Brine constitutes 45% by weight of the mixture, and the fluid first boiled at approximately 1 km below the seafloor at 415??C, 330 bar. A 400??C vent is primarily vapor (88 wt.%, 0.044% NaCl) with a small amount of brine (26% NaCl) and first boiled at 2.9 km below the seafloor at 500??C, 520 bar. These results show that adiabatic decompression in the two-phase region results in dramatic cooling of the fluid mixture when there is a large fraction of vapor. ?? 1985.

Effects of boiling and frying on the bioaccessibility of beta-carotene in yellow-fleshed cassava roots (Manihot esculenta Crantz cv. BRS Jari).

PubMed

Gomes, Suellen; Torres, Alexandre Guedes; Godoy, Ronoel; Pacheco, Sidney; Carvalho, José; Nutti, Marília

2013-03-01

The effects of boiling and frying on the bioaccessibility of all-trans-beta-carotene in biofortified BRS Jari cassava roots have not been investigated, although these are conventional methods of cassava preparation. The aims of the present study were to investigate beta-carotene micellarization efficiency of yellow-fleshed BRS Jari cassava roots after boiling and frying, as an indicator of the bioaccessibility of this carotenoid, and to apply fluorescence microscopy to investigate beta-carotene in the emulsified fraction. Uncooked, boiled, and fried cassava roots were digested in vitro for the evaluation, by reversed-phase high-performance liquid chromatography (HPLC), of the efficiency of micellarization of all-trans-beta-carotene in BRS Jari cassava roots. Fluorescence microscopy of the micellar fraction was used to confirm the presence of beta-carotene in the emulsified fraction and to observe the structure of the microemulsion from the boiled and fried cassava samples. Fried cassava roots showed the highest (p < .05) micellarization efficiency for total carotenoids and all-trans-beta-carotene (14.1 +/- 2.25% and 14.37 +/- 2.44%, respectively), compared with boiled and raw samples. Fluorescence microscopy showed that after in vitro digestion there were no carotenoid crystals in the micellar fraction, but rather that this fraction presented a biphasic system compatible with emulsified carotenoids, which was consistent with the expected high bioavailability of beta-carotene in this fraction. Increased emulsification and bioaccessibility of beta-carotene from fried biofortified BRS Jari cassava roots compensates for chemical losses during preparation, indicating that this preparation is suitable for home use of BRS Jari cassava roots and might represent a relatively good food source of bioavailable provitamin A.

Distribution of Trichloroethylene and Geologic Controls on Contaminant Pathways near the Royal River, McKin Superfund Site Area, Gray, Maine

USGS Publications Warehouse

Lyford, Forest P.; Flight, L.E.; Stone, Janet Radway; Clifford, Scott

1999-01-01

Vapor-diffusion samplers were used in the autumn of 1997 to determine the lateral extent and distribution of concentrations of a trichloroethylene (TCE) plume in the ground-water discharge area near the McKin Superfund Site, Gray, Maine. Analyses of vapor in the samplers identified a plume about 800 feet wide entering the river near Boiling Springs, an area of ground-water discharge on the flood plain of the Royal River. The highest observed concentration of TCE in vapor was in an area of sand boils on the western bank of the river and about 200 feet downstream from Boiling Springs. Previous studies showed that most of the TCE load in the river originated in the area of the sand boils. In general, highest concentrations were observed on the western side of the river on the upgradient side of the plume, but TCE also was detected at numerous locations in the center and eastern bank of the river. The TCE plume discharges to the river where fine-grained glaciomarine sediments of the Presumpscot Formation are absent and where coarse-grained facies of buried glaciomarine fan deposits provide a pathway for ground-water flow. Based on results of analyses of vapor-diffusion samples and other previous studies, the plume appears to pass under and beyond the river near Boiling Springs and along the river for about 300 feet downstream from the sand boils. A coarse-grained, organic-rich layer at the base of the alluvial flood plain sediments is confined by overlying fine-grained alluvial sediments and may provide a conduit for ground-water leaking upward from buried glaciomarine fan deposits.

Survey of Thermal-Fluids Evaluation and Confirmatory Experimental Validation Requirements of Accident Tolerant Cladding Concepts with Focus on Boiling Heat Transfer Characteristics

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

Brown, Nicholas R.; Wysocki, Aaron J.; Terrani, Kurt A.

The U.S. Department of Energy Office of Nuclear Energy (DOE-NE) Advanced Fuels Campaign (AFC) is working closely with the nuclear industry to develop fuel and cladding candidates with potentially enhanced accident tolerance, also known as accident tolerant fuel (ATF). Thermal-fluids characteristics are a vital element of a holistic engineering evaluation of ATF concepts. One vital characteristic related to boiling heat transfer is the critical heat flux (CHF). CHF plays a vital role in determining safety margins during normal operation and also in the progression of potential transient or accident scenarios. This deliverable is a scoping survey of thermal-fluids evaluation andmore » confirmatory experimental validation requirements of accident tolerant cladding concepts with a focus on boiling heat transfer characteristics. The key takeaway messages of this report are: 1. CHF prediction accuracy is important and the correlations may have significant uncertainty. 2. Surface conditions are important factors for CHF, primarily the wettability that is characterized by contact angle. Smaller contact angle indicates greater wettability, which increases the CHF. Surface roughness also impacts wettability. Results in the literature for pool boiling experiments indicate changes in CHF by up to 60% for several ATF cladding candidates. 3. The measured wettability of FeCrAl (i.e., contact angle and roughness) indicates that CHF should be investigated further through pool boiling and flow boiling experiments. 4. Initial measurements of static advancing contact angle and surface roughness indicate that FeCrAl is expected to have a higher CHF than Zircaloy. The measured contact angle of different FeCrAl alloy samples depends on oxide layer thickness and composition. The static advancing contact angle tends to decrease as the oxide layer thickness increases.« less

Liquid-vapor phase relations in the Si-O system: A calorically constrained van der Waals-type model

NASA Astrophysics Data System (ADS)

Connolly, James A. D.

2016-09-01

This work explores the use of several van der Waals (vW)-type equations of state (EoS) for predicting vaporous phase relations and speciation in the Si-O system, with emphasis on the azeotropic boiling curve of SiO2-rich liquid. Comparison with the observed Rb and Hg boiling curves demonstrates that prediction accuracy is improved if the a-parameter of the EoS, which characterizes vW forces, is constrained by ambient pressure heat capacities. All EoS considered accurately reproduce metal boiling curve trajectories, but absent knowledge of the true critical compressibility factor, critical temperatures remain uncertain by ~500 K. The EoS plausibly represent the termination of the azeotropic boiling curve of silica-rich liquid by a critical point across which the dominant Si oxidation state changes abruptly from the tetravalent state characteristic of the liquid to the divalent state characteristic of the vapor. The azeotropic composition diverges from silica toward metal-rich compositions with increasing temperature. Consequently, silica boiling is divariant and atmospheric loss after a giant impact would enrich residual silicate liquids in reduced silicon. Two major sources of uncertainty in the boiling curve prediction are the heat capacity of silica liquid, which may decay during depolymerization from the near-Dulong-Petit limit heat capacity of the ionic liquid to value characteristic of the molecular liquid, and the unknown liquid affinity of silicon monoxide. Extremal scenarios for these uncertainties yield critical temperatures and compositions of 5200-6200 K and Si1.1O2-Si1.4O2. The lowest critical temperatures are marginally consistent with shock experiments and are therefore considered more probable.

Nano-inspired fluidic interactivity for boiling heat transfer: impact and criteria

PubMed Central

Kim, Beom Seok; Choi, Geehong; Shin, Sangwoo; Gemming, Thomas; Cho, Hyung Hee

2016-01-01

The enhancement of boiling heat transfer, the most powerful energy-transferring technology, will lead to milestones in the development of high-efficiency, next-generation energy systems. Perceiving nano-inspired interface functionalities from their rough morphologies, we demonstrate interface-induced liquid refreshing is essential to improve heat transfer by intrinsically avoiding Leidenfrost phenomenon. High liquid accessibility of hemi-wicking and catalytic nucleation, triggered by the morphological and hydrodynamic peculiarities of nano-inspired interfaces, contribute to the critical heat flux (CHF) and the heat transfer coefficient (HTC). Our experiments show CHF is a function of universal hydrodynamic characteristics involving interfacial liquid accessibility and HTC is improved with a higher probability of smaller nuclei with less superheat. Considering the interface-induced and bulk liquid accessibility at boiling, we discuss functionalizing the interactivity between an interface and a counteracting fluid seeking to create a novel interface, a so-called smart interface, for a breakthrough in boiling and its pragmatic application in energy systems. PMID:27708341

Changes provoked by boiling, steaming and sous-vide cooking in the lipid and volatile profile of European sea bass.

PubMed

Nieva-Echevarría, Bárbara; Manzanos, María J; Goicoechea, Encarnación; Guillén, María D

2017-09-01

This study aims to shed light on the changes provoked by boiling, steaming and sous-vide cooking on the lipids and volatile profile of farmed and wild European sea bass meat. None of the cooking techniques provoked changes due to hydrolytic or oxidation processes detectable by 1 H NMR on sea bass lipids. The lipid profile of main and minor lipidic components was maintained after cooking. However, study by SPME-GC/MS evidenced that steaming and sous-vide cooking modified the volatile profile of sea bass meat, especially in farmed specimens. The compounds generated came from the occurrence, to a very small extent, of lipid and protein degradation. By contrast, boiling scarcely modified the initial characteristics of raw sea bass. Thus, from a sensory point of view and considering the odour-active compounds generated, steaming and sous-vide cooking provoked more noticeable changes than boiling, especially in farmed sea bass meat. Copyright © 2017. Published by Elsevier Ltd.

Prediction of boiling points of organic compounds by QSPR tools.

PubMed

Dai, Yi-min; Zhu, Zhi-ping; Cao, Zhong; Zhang, Yue-fei; Zeng, Ju-lan; Li, Xun

2013-07-01

The novel electro-negativity topological descriptors of YC, WC were derived from molecular structure by equilibrium electro-negativity of atom and relative bond length of molecule. The quantitative structure-property relationships (QSPR) between descriptors of YC, WC as well as path number parameter P3 and the normal boiling points of 80 alkanes, 65 unsaturated hydrocarbons and 70 alcohols were obtained separately. The high-quality prediction models were evidenced by coefficient of determination (R(2)), the standard error (S), average absolute errors (AAE) and predictive parameters (Qext(2),RCV(2),Rm(2)). According to the regression equations, the influences of the length of carbon backbone, the size, the degree of branching of a molecule and the role of functional groups on the normal boiling point were analyzed. Comparison results with reference models demonstrated that novel topological descriptors based on the equilibrium electro-negativity of atom and the relative bond length were useful molecular descriptors for predicting the normal boiling points of organic compounds. Copyright © 2013 Elsevier Inc. All rights reserved.

Microwave-Assisted Superheating and/or Microwave-Specific Superboiling (Nucleation-Limited Boiling) of Liquids Occurs under Certain Conditions but is Mitigated by Stirring.

PubMed

Ferrari, Anthony; Hunt, Jacob; Stiegman, Albert; Dudley, Gregory B

2015-12-04

Temporary superheating and sustained nucleation-limited "superboiling" of unstirred liquids above the normal atmospheric boiling point have been documented during microwave heating. These phenomena are reliably observed under prescribed conditions, although the duration (of superheating) and magnitude (of superheating and superboiling) vary according to system parameters such as volume of the liquid and the size and shape of the vessel. Both phenomena are mitigated by rapid stirring with an appropriate stir bar and/or with the addition of boiling chips, which provide nucleation sites to support the phase-change from liquid to gas. With proper experimental design and especially proper stirring, the measured temperature of typical organic reaction mixtures heated at reflux will be close to the normal boiling point temperature of the solvent, whether heated using microwave radiation or conventional convective heat transfer. These observations are important to take into consideration when comparing reaction rates under conventional and microwave heating.

Microbiological effectiveness and cost of disinfecting water by boiling in semi-urban India.

PubMed

Clasen, Thomas; McLaughlin, Catherine; Nayaar, Neeru; Boisson, Sophie; Gupta, Romesh; Desai, Dolly; Shah, Nimish

2008-09-01

Despite shortcomings, boiling is the most common means of treating water at home and the benchmark against which emerging point-of-use water treatment approaches are measured. In a 5-month study, we assessed the microbiological effectiveness and cost of the practice among 218 self-reported boilers relying on unprotected water supplies. Boiling was associated with a 99% reduction in geometric mean fecal coliforms (FCs; P < 0.001). Despite high levels of fecal contamination in source water, 59.6% of stored drinking water samples from self-reported boilers met the World Health Organization standard for safe drinking water (0 FC/100 mL), and 5.7% were between 1 and 10 FC/100 mL. Nevertheless, 40.4% of stored drinking water samples were positive for FCs, with 25.1% exceeding 100 FC/100 mL. The estimated monthly fuel cost for boiling was INR 43.8 (US$0.88) for households using liquid petroleum gas and INR 34.7 (US$0.69) for households using wood.

Effect of processing on nutrients and fatty acid composition of garden cress (Lepidium sativum) seeds.

PubMed

Jain, Tanu; Grover, Kiran; Kaur, Gurpreet

2016-12-15

Garden cress seeds were undergone for different processing methods and analyzed for its nutritional composition. Effect of processing on nutrient retention was evaluated to attain the best processed form of seeds with maximum amount of nutrients. Soaking improved protein and ash by 2.10 and 2.48 percent respectively. Boiling improved fat and fibre by 1.66 and 8.32 percent respectively. Maximum retention of iron and zinc was found with roasting. It also improved calcium by 3.18 percent. Percent ionizable iron and bioavailability was found maximum with boiling (13.59 and 6.88% respectively). In vitro starch and protein digestibility were found maximum on boiling (57.98 and 32.39% respectively) with a decrease of 9.65 and 14.13 percent in phytin phosphorus and oxalate respectively. Amino acids and fatty acids were decreased with heat treatment and maximum retention was found with soaking. Overall improvement in nutrient composition and maximum nutrient retention was found with boiling method. Copyright © 2016 Elsevier Ltd. All rights reserved.

Lead, cadmium and chromium in raw and boiled portions of Norway lobster.

PubMed

Perugini, Monia; Visciano, Pierina; Manera, Maurizio; Abete, Maria Cesarina; Tarasco, Renata; Amorena, Michele

2014-01-01

Lead, cadmium and chromium levels were determined in different raw and boiled portions of Norway lobster caught in the central Adriatic Sea (Italy). In raw specimens, the lowest concentrations were always detected in the white meat. Lead and cadmium content in the edible portion never exceeded the maximum levels set by European legislation. The highest cadmium and chromium values (0.47 ± 0.04 and 0.62 ± 0.13 mg/kg wet weight, respectively) were detected in the brown meat, while the highest lead concentrations were found in the exoskeleton (0.21 ± 0.01 mg/kg wet weight). Also, the boiled samples showed the lowest metal levels in the white meat, even if a significant increase (p < 0.01) was found for lead and cadmium compared to the corresponding raw portions. Among metals, chromium showed the highest concentrations in both raw and boiled portions, but up to now, the European legislation did not envisage any limits in seafood.

Effects of two different domestic boiling practices on the allergenicity of cow's milk proteins.

PubMed

Lamberti, Cristina; Baro, Cristina; Giribaldi, Marzia; Napolitano, Lorenzo; Cavallarin, Laura; Giuffrida, Maria Gabriella

2018-04-01

The sale of raw drinking milk through automatic dispensers is permitted in some EU member states, but consumers are usually advised to boil the milk before consumption. The present study has been conducted to evaluate the effects of two common domestic boiling techniques on the proteins of raw milk and, in particular, on their potential allergenicity. Native one-dimensional electrophoresis, N-terminal amino acid sequencing and immunoblotting have been used to characterize the protein pattern and to evaluate the possible changes in the allergenic properties of the processed milk. The main result of this investigation is that heating induces the aggregation of β-lactoglobulin in higher-molecular-weight products, while caseins seem to be more resistant to the treatments. β-Lactoglobulin aggregates have been found to be non-immunoreactive with the sera of subjects suffering from cow's milk protein allergy. Domestic boiling modifies the milk protein profile, causing a minor reduction in milk allergenicity. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

Effects of baking and boiling on the nutritional and antioxidant properties of sweet potato [Ipomoea batatas (L.) Lam.] cultivars.

PubMed

Dincer, Cuneyt; Karaoglan, Mert; Erden, Fidan; Tetik, Nedim; Topuz, Ayhan; Ozdemir, Feramuz

2011-11-01

The effects of baking and boiling on the nutritional and antioxidant properties of three sweet potato cultivars (Beniazuma, Koganesengan, Kotobuki) cultivated in Turkey were investigated. The samples were analyzed for proximate composition, total phenolic content, ascorbic acid, β-carotene, antiradical activity, and free sugars. The dry matter, protein, and starch contents of the sweet potatoes were significantly changed by the treatments while the ash and crude fiber contents did not differ as significantly. The β-carotene contents of baked and boiled sweet potatoes were lower than those of fresh sweet potatoes; however, the total phenolic and ascorbic acid contents of the baked and boiled sweet potatoes were higher than those of the fresh samples. Generally, the antiradical activity of the sweet potatoes increased with the treatments. Sucrose, glucose, and fructose were quantified as free sugars in all fresh sweet potatoes; however, maltose was determined in the treated samples. In terms of the analyzed parameters, there were no explicit differences among the sweet potato cultivars.

Effects of water soaking and/or sodium polystyrene sulfonate addition on potassium content of foods.

PubMed

Picq, Christian; Asplanato, Marion; Bernillon, Noémie; Fabre, Claudie; Roubeix, Mathilde; Ricort, Jean-Marc

2014-09-01

In this study, we determined, by atomic absorption spectrophotometry, the potassium amount leached by soaking or boiling foods identified by children suffering from chronic renal failure as "pleasure food" and that they cannot eat because of their low-potassium diet, and evaluated whether addition of sodium polystyrene sulfonate resin (i.e. Kayexalate®) during soaking or boiling modulated potassium loss. A significant amount of potassium content was removed by soaking (16% for chocolate and potato, 26% for apple, 37% for tomato and 41% for banana) or boiling in a large amount of water (73% for potato). Although Kayexalate® efficiently dose-dependently removed potassium from drinks (by 48% to 73%), resin addition during soaking or boiling did not eliminate more potassium from solid foods. Our results therefore provide useful information for dietitians who elaborate menus for people on potassium-restricted diets and would give an interesting alternative to the systematic elimination of all potassium-rich foods from their diet.

Micro-bubble emission boiling with the cavitation bubble blow pit

PubMed Central

Inada, Shigeaki; Shinagawa, Kazuaki; Illias, Suhaimi Bin; Sumiya, Hiroyuki; Jalaludin, Helmisyah A.

2016-01-01

The miniaturization boiling (micro-bubble emission boiling [MEB]) phenomenon, with a high heat removal capacity that contributes considerably to the cooling of the divertor of the nuclear fusion reactor, was discovered in the early 1980s. Extensive research on MEB has been performed since its discovery. However, the progress of the application has been delayed because the generation mechanism of MEB remains unclear. Reasons for this lack of clarity include the complexity of the phenomenon itself and the high-speed phase change phenomenon in which boiling and condensation are rapidly generated. In addition, a more advanced thermal technique is required to realize the MEB phenomenon at the laboratory scale. To the authors’ knowledge, few studies have discussed the rush mechanism of subcooled liquid to the heating surface, which is critical to elucidating the mechanism behind MEB. This study used photographic images to verify that the cavitation phenomenon spreads to the inside of the superheated liquid on the heating surface and thus clarify the mechanism of MEB. PMID:27628271

Gas chemistry and thermometry of the Cerro Prieto, Mexico, geothermal field

USGS Publications Warehouse

Nehring, N.L.; D'Amore, F.

1984-01-01

Gas compositions of Cerro Prieto wells in 1977 reflected strong boiling in the reservoir around wells M-20 and M-25. This boiling zone appeared to be collapsing in 1982 when a number of wells in this area of the field were shut-in. In 1977 and 1982, gas compositions also showed boiling zones corresponding to faults H and L postulated by Halfman et al. (1982). Four gas geothermometers were applied, based on reservoir equilibria and calculated fugacities. The Fisher - Tropsch reaction predicted high temperatures and appeared to re-equilibrate slowly, whereas the H2S reaction predicted low temperatures and appeared to re-equilibrate rapidly. Hydrogen and NH3 reactions were intermediate. Like gas compositions, the geothermometers reflected reservoir processes, such as boiling. Surface gas compositions are related to well compositions, but contain large concentrations of N2 originating from air dissolved in groundwater. The groundwater appears to originate in the east and flow over the production field before mixing with reservoir gases near the surface. ?? 1984.

Use of once-through treat gas to remove the heat of reaction in solvent hydrogenation processes

DOEpatents

Nizamoff, Alan J.

1980-01-01

In a coal liquefaction process wherein feed coal is contacted with molecular hydrogen and a hydrogen-donor solvent in a liquefaction zone to form coal liquids and vapors and coal liquids in the solvent boiling range are thereafter hydrogenated to produce recycle solvent and liquid products, the improvement which comprises separating the effluent from the liquefaction zone into a hot vapor stream and a liquid stream; cooling the entire hot vapor stream sufficiently to condense vaporized liquid hydrocarbons; separating condensed liquid hydrocarbons from the cooled vapor; fractionating the liquid stream to produce coal liquids in the solvent boiling range; dividing the cooled vapor into at least two streams; passing the cooling vapors from one of the streams, the coal liquids in the solvent boiling range, and makeup hydrogen to a solvent hydrogenation zone, catalytically hydrogenating the coal liquids in the solvent boiling range and quenching the hydrogenation zone with cooled vapors from the other cooled vapor stream.

Ares I Reaction Control System Propellant Feedline Decontamination Modeling

NASA Technical Reports Server (NTRS)

Pasch, James J.

2010-01-01

The objective of the work presented here is to quantify the effects of purge gas temperature, pressure, and mass flow rate on Hydrazine (Hz) decontamination rates of the Ares I Roll Control System and Reaction Control System. A survey of experts in this field revealed the absence of any decontamination rate prediction models. Three basic decontamination methods were identified for analysis and modeling. These include low pressure eduction, high flow rate purge, and pulse purge. For each method, an approach to predict the Hz mass transfer rate, as a function of system pressure, temperature, and purge gas mass flow rate, is developed based on the applicable physics. The models show that low pressure eduction is two orders of magnitude more effective than the high velocity purge, which in turn is two orders of magnitude more effective than the pure diffusion component of pulse purging of deadheads. Eduction subjects the system to low pressure conditions that promote the extraction of Hz vapors. At 120 F, Hz is saturated at approximately 1 psia. At lower pressures and 120 F, Hz will boil, which is an extremely efficient means to remove liquid Hz. The Hz boiling rate is predicted by equating the rate at which energy is added to the saturated liquid Hz through heaters at the tube outer wall with the energy removed from the liquid through evaporation. Boil-off fluxes were predicted by iterating through the range of local pressures with limits set by the minimum allowed pressure of 0.2 psia and maximum allowed wall temperature of 120 F established by the heaters, which gives a saturation pressure of approximately 1.0 psia. Figure 1 shows the resulting boil-off fluxes as a function of local eduction pressure. As depicted in figure 1, the flux is a strong inverse function of eduction pressure, and that minimizing the eduction pressure maximizes the boil-off flux. Also, higher outer wall temperatures lead to higher boil-off fluxes and allow for boil-off over a greater range of eduction pressures.

Group vector space method for estimating enthalpy of vaporization of organic compounds at the normal boiling point.

PubMed

Wenying, Wei; Jinyu, Han; Wen, Xu

2004-01-01

The specific position of a group in the molecule has been considered, and a group vector space method for estimating enthalpy of vaporization at the normal boiling point of organic compounds has been developed. Expression for enthalpy of vaporization Delta(vap)H(T(b)) has been established and numerical values of relative group parameters obtained. The average percent deviation of estimation of Delta(vap)H(T(b)) is 1.16, which show that the present method demonstrates significant improvement in applicability to predict the enthalpy of vaporization at the normal boiling point, compared the conventional group methods.

A new hydrodynamic prediction of the peak heat flux from horizontal cylinders in low speed upflow

NASA Technical Reports Server (NTRS)

Ungar, E. K.; Eichhorn, R.

1988-01-01

Flow-boiling data have been obtained for horizontal cylinders in saturated acetone, isopropanol, and water, yielding heat flux vs. wall superheat boiling curves for the organic liquids. A region of low speed upflow is identified in which long cylindrical bubbles break off from the wake with regular frequency. The Strouhal number of bubble breakoff is a function only of the Froude number in any liquid, and the effective wake thickness in all liquids is a function of the density ratio and the Froude number. A low speed flow boiling burnout prediction procedure is presented which yields accurate results in widely dissimilar liquids.

Comparison of boiling and chlorination on the quality of stored drinking water and childhood diarrhoea in Indonesian households.

PubMed

Fagerli, K; Trivedi, K K; Sodha, S V; Blanton, E; Ati, A; Nguyen, T; Delea, K C; Ainslie, R; Figueroa, M E; Kim, S; Quick, R

2017-11-01

We compared the impact of a commercial chlorination product (brand name Air RahMat) in stored drinking water to traditional boiling practices in Indonesia. We conducted a baseline survey of all households with children 1000 MPN/100 ml (RR 1·86, 95% CI 1·09-3·19) in stored water than in households without detectable E. coli. Although results suggested that Air RahMat water treatment was associated with lower E. coli contamination and diarrhoeal rates among children <5 years than water treatment by boiling, Air RahMat use remained low.

Liquid metal boiling inception

NASA Technical Reports Server (NTRS)

Sabin, C. M.; Poppendiek, H. F.; Mouritzen, G.; Meckel, P. T.; Cloakey, J. E.

1972-01-01

An experimental study of the inception of boiling in potassium in forced convection is reported. The boiler consisted of a 0.19-inch inside diameter, niobium-1% zirconium boiler tube approximately six feet long. Heating was accomplished by direct electrical tube wall conduction. Experiments were performed with both all-liquid fill and two-phase fill startup sequences and with a range of flow rates, saturation temperatures, inert gas levels, and fill liquid temperatures. Superheat of the liquid above the equilibrium saturation temperature was observed in all the experiments. Incipient boiling liquid superheat ranged from a few degrees to several hundred. Comparisons of these data with other data and with several analytical treatments are presented.

BOILING SLURRY REACTOR AND METHOD FO CONTROL

DOEpatents

Petrick, M.; Marchaterre, J.F.

1963-05-01

The control of a boiling slurry nuclear reactor is described. The reactor consists of a vertical tube having an enlarged portion, a steam drum at the top of the vertical tube, and at least one downcomer connecting the steam drum and the bottom of the vertical tube, the reactor being filled with a slurry of fissionabie material in water of such concentration that the enlarged portion of the vertical tube contains a critical mass. The slurry boils in the vertical tube and circulates upwardly therein and downwardly in the downcomer. To control the reactor by controlling the circulation of the slurry, a gas is introduced into the downcomer. (AEC)

Influence of the heater material on the critical heat load at boiling of liquids on surfaces with different sizes

NASA Astrophysics Data System (ADS)

Anokhina, E. V.

2010-05-01

Data on critical heat loads q cr for the saturated and unsaturated pool boiling of water and ethanol under atmospheric pressure are reported. It is found experimentally that the critical heat load does not necessarily coincide with the heat load causing burnout of the heater, which should be taken into account. The absolute values of q cr for the boiling of water and ethanol on copper surfaces 65, 80, 100, 120, and 200 μm in diameter; tungsten surface 100 μm in diameter; and nichrome surface 100 μm in diameter are obtained experimentally.

Effect of cooking on residues of the quinolones oxolinic acid and flumequine in fish.

PubMed

Steffenak, I; Hormazabal, V; Yndestad, M

1994-01-01

The effect of cooking on residues of the quinolones oxolinic acid and flumequine in fish was investigated. Salmon containing residues of oxolinic acid and flumequine was boiled or baked in the oven. Samples of raw and cooked muscle, skin, and bone, as well as of the water in which the fish was boiled and juice from the baked fish, were analysed. Oxolinic acid and flumequine did not degrade at the temperatures reached when cooking the fish. However, fish muscle free from drug residues may be contaminated during boiling and baking due to leakage of the drug from reservoirs in the fish.

Heterogeneous boiling-up of superheated liquid at achievable superheat threshold.

PubMed

Ermakov, G V; Lipnyagov, E V; Perminov, S A; Gurashkin, A L

2009-07-21

The classical theory of homogeneous nucleation describes well the superheat threshold observed in experiments. It may be assumed therefore that homogeneous boiling-up of a liquid takes place in experiments, and the theory has been verified experimentally well. The streak photography used in this study showed that boiling-up of a superheated liquid at the threshold of the achievable superheat occurs at a limited number of surface fluctuation centers in a vessel, rather than in the bulk as one would expect with homogeneous nucleation. Thus, the homogeneous theory, which rather accurately describes the heterogeneous threshold of the achievable superheat, obviously is not confirmed in experiments.

8. Innovative Technologies: Two-Phase Heat Transfer in Water-Based Nanofluids for Nuclear Applications Final Report

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

Buongiorno, Jacopo; Hu, Lin-wen

2009-07-31

Nanofluids are colloidal dispersions of nanoparticles in water. Many studies have reported very significant enhancement (up to 200%) of the Critical Heat Flux (CHF) in pool boiling of nanofluids (You et al. 2003, Vassallo et al. 2004, Bang and Chang 2005, Kim et al. 2006, Kim et al. 2007). These observations have generated considerable interest in nanofluids as potential coolants for more compact and efficient thermal management systems. Potential Light Water Reactor applications include the primary coolant, safety systems and severe accident management strategies, as reported in other papers (Buongiorno et al. 2008 and 2009). However, the situation of interestmore » in reactor applications is often flow boiling, for which no nanofluid data have been reported so far. In this project we investigated the potential of nanofluids to enhance CHF in flow boiling. Subcooled flow boiling heat transfer and CHF experiments were performed with low concentrations of alumina, zinc oxide, and diamond nanoparticles in water (≤ 0.1 % by volume) at atmospheric pressure. It was found that for comparable test conditions the values of the nanofluid and water heat transfer coefficient (HTC) are similar (within ±20%). The HTC increased with mass flux and heat flux for water and nanofluids alike, as expected in flow boiling. The CHF tests were conducted at 0.1 MPa and at three different mass fluxes (1500, 2000, 2500 kg/m2s) under subcooled conditions. The maximum CHF enhancement was 53%, 53% and 38% for alumina, zinc oxide and diamond, respectively, always obtained at the highest mass flux. A post-mortem analysis of the boiling surface reveals that its morphology is altered by deposition of the particles during nanofluids boiling. A confocal-microscopy-based examination of the test section revealed that nanoparticles deposition not only changes the number of micro-cavities on the surface, but also the surface wettability. A simple model was used to estimate the ensuing nucleation site density changes, but no definitive correlation between the nucleation site density and the heat transfer coefficient data could be found. Wettability of the surface was substantially increased for heater coupons boiled in alumina and zinc oxide nanofluids, and such wettability increase seems to correlate reasonably well with the observed marked CHF enhancement for the respective nanofluids. Interpretation of the experimental data was conducted in light of the governing surface parameters (surface area, contact angle, roughness, thermal conductivity) and existing models. It was found that no single parameter could explain the observed HTC or CHF phenomena.« less

Carotenoids and β-carotene in orange fleshed sweet potato: A possible solution to vitamin A deficiency.

PubMed

Islam, Sheikh Nazrul; Nusrat, Tania; Begum, Parveen; Ahsan, Monira

2016-05-15

The present study, in line with a plant-food-based approach to address vitamin A deficiency, reports the analysis of total carotenoids, and trans- and cis-β-carotenes, in different varieties of raw and boiled orange-fleshed sweet potatoes (OFSP). Carotenoids were isolated using acetone-petroleum ether extraction followed by spectrophotometric determination. trans- and cis-β-Carotenes were analyzed by reversed-phase HPLC method using a mobile phase containing acetonitrile:methanol:2-propanol in the ratio of 85:15:33 with 0.01% ammonium acetate. Intra-varietal difference in carotenoids as well as trans- and cis-β-carotenes were noted in both the raw and boiled potatoes. Carotenoid content was found to be higher in the raw potatoes compared to the boiled samples from the same variety. Amongst the OFSP varieties, Kamalasundari (BARI SP-2) was found to contain the most carotenoids in both the raw and boiled samples. β-Carotene was significantly higher in the Kamalsundari and BARI SP-5 varieties. trans-β-Carotene was found to be the major carotenoid in all of the raw potatoes, but boiling was associated with an increase in cis-β-carotene and a decrease in the trans isomer. Kamalsundari and BARI SP-5 orange-fleshed sweet potatoes have the potential to be used as food-based supplements to reduce vitamin A deficiency. Copyright © 2015 Elsevier Ltd. All rights reserved.