[Study on extraction of the total saponins of Chinese yam].

PubMed

Zhang, Min; Du, Lin; Huang, Gui-dong; Zhong, Xian-feng

2007-07-01

A method for the determination of total saponins of Chinese yam was established. The dioscin was used as a standard compound, the vanillin-perchloric acid as chromogenic agent and glacial acetic acid as solvent. The extraction technique of asponins from Chinese yam was studied by spectrometric method. Extracting temperature, extracting time, ethanol concentration and the ratio of raw material and water were selected as four factors to design the orthogonal test, and the optical condition of extraction was obtained. The results showed that the optical condition of extraction was as following: extracting temperature 60 degrees C, extracting time 6 h, ethanol concetration 80%, and the ratio of raw material and water 1:8.

Topology of microwave background fluctuations - Theory

NASA Technical Reports Server (NTRS)

Gott, J. Richard, III; Park, Changbom; Bies, William E.; Bennett, David P.; Juszkiewicz, Roman

1990-01-01

Topological measures are used to characterize the microwave background temperature fluctuations produced by 'standard' scenarios (Gaussian) and by cosmic strings (non-Gaussian). Three topological quantities: total area of the excursion regions, total length, and total curvature (genus) of the isotemperature contours, are studied for simulated Gaussian microwave background anisotropy maps and then compared with those of the non-Gaussian anisotropy pattern produced by cosmic strings. In general, the temperature gradient field shows the non-Gaussian behavior of the string map more distinctively than the temperature field for all topology measures. The total contour length and the genus are found to be more sensitive to the existence of a stringy pattern than the usual temperature histogram. Situations when instrumental noise is superposed on the map, are considered to find the critical signal-to-noise ratio for which strings can be detected.

Induction of glutathione synthesis and glutathione reductase activity by abiotic stresses in maize and wheat.

PubMed

Kocsy, Gábor; Szalai, Gabriella; Galiba, Gábor

2002-06-21

The effect of different abiotic stresses (extreme temperatures and osmotic stress) on the synthesis of glutathione and hydroxymethylglutathione, on the ratio of the reduced to oxidised forms of these thiols (GSH/GSSG, hmGSH/hmGSSG), and on the glutathione reductase (GR) activity was studied in maize and wheat genotypes having different sensitivity to low temperature stress. Cold treatment induced a greater increase in total glutathione (TG) content and in GR activity in tolerant genotypes of both species than in sensitive ones. The GSH/GSSG and hmGSH/hmGSSG ratios were increased by this treatment only in the frost-tolerant wheat variety. High-temperature stress increased the TG content and the GSH/GSSG ratio only in the chilling-sensitive maize genotype, but GR activity was greater after this treatment in both maize genotypes. Osmotic stress resulted in a great increase in the TG content in wheat and the GR activity in maize. The amount of total hydroxymethylglutathione increased following all stress treatments. These results indicate the involvement of these antioxidants in the stress responses of wheat and maize.

Ultrasonically assisted extraction of total phenols and flavonoids from Rhodiola rosea.

PubMed

Staneva, Jordanka; Todorova, Milka; Neykov, Neyko; Evstatieva, Ljuba

2009-07-01

This work deals with ultrasonically assisted extraction (UAE) of biologically active compounds from rhizomes of Rhodiola rosea, a popular medicinal plant. The influence of temperature, type of solvent and solid/solvent ratio on the yield of total extracts, total phenols and flavonoids was established. The best extraction of total phenols and flavonoids was achieved by using 50% aqueous EtOH and MeOH, respectively. Five times increase of solid/solvent ratio (from 1:20 to 1:100 (w/v)) leads to slow increase of the yield of total phenols and flavonoids. The extraction effectiveness of conventional maceration with 50% EtOH and UAE performed for 1 h at 25 degrees C using the same solvent with respect of total phenols was comparable.

Pitot-Pressure Measurements in Flow Fields Behind a Rectangular Nozzle with Exhaust Jet for Free-Stream Mach Numbers of 0.00, 0.60, and 1.20

NASA Technical Reports Server (NTRS)

Putnam, L. E.; Mercer, C. E.

1986-01-01

An investigation has been conducted in the Langley 16-Foot Transonic Tunnel to measure the flow field in and around the jet exhaust from a nonaxisymmetric nozzle configuration. The nozzle had a rectangular exit with a width-to-height ratio of 2.38. Pitot-pressure measurements were made at five longitudinal locations downstream of the nozzle exit. The maximum distance downstream of the exit was about 5 nozzle heights. These measurements were made at free-stream Mach numbers of 0.00, 0.60, and 1.20 with the nozzle operating at a ratio of nozzle total pressure to free-stream static pressure of 4.0. The jet exhaust was simulated with high-pressure air that had an exit total temperature essentially equal to the free-stream total temperature.

Permalloy-Based Thin Film Structures: Magnetic Properties and the Giant Magnetoimpedance Effect in the Temperature Range Important for Biomedical Applications

PubMed Central

Chlenova, Anna A.; Moiseev, Alexey A.; Derevyanko, Mikhail S.; Semirov, Aleksandr V.; Lepalovsky, Vladimir N.

2017-01-01

Permalloy-based thin film structures are excellent materials for sensor applications. Temperature dependencies of the magnetic properties and giant magneto-impedance (GMI) were studied for Fe19Ni81-based multilayered structures obtained by the ion-plasma sputtering technique. Selected temperature interval of 25 °C to 50 °C corresponds to the temperature range of functionality of many devices, including magnetic biosensors. A (Cu/FeNi)5/Cu/(Cu/FeNi)5 multilayered structure with well-defined traverse magnetic anisotropy showed an increase in the GMI ratio for the total impedance and its real part with temperature increased. The maximum of the GMI of the total impedance ratio ΔZ/Z = 56% was observed at a frequency of 80 MHz, with a sensitivity of 18%/Oe, and the maximum GMI of the real part ΔR/R = 170% at a frequency of 10 MHz, with a sensitivity of 46%/Oe. As the magnetization and direct current electrical resistance vary very little with the temperature, the most probable mechanism of the unexpected increase of the GMI sensitivity is the stress relaxation mechanism associated with magnetoelastic anisotropy. PMID:28817084

Performance Charts for a Turbojet System

NASA Technical Reports Server (NTRS)

Karp, Irving M.

1947-01-01

Convenient charts are presented for computing the thrust, fuel consumption, and other performance values of a turbojet system. These charts take into account the effects of ram pressure, compressor pressure ratio, ratio of combustion-chamber-outlet temperature to atmospheric temperature, compressor efficiency, turbine efficiency, combustion efficiency, discharge-nozzle coefficient, losses in total pressure in the inlet to the jet-propulsion unit and in the combustion chamber, and variation in specific heats with temperature. The principal performance charts show clearly the effects of the primary variables and correction charts provide the effects of the secondary variables. The performance of illustrative cases of turbojet systems is given. It is shown that maximum thrust per unit mass rate of air flow occurs at a lower compressor pressure ratio than minimum specific fuel consumption. The thrust per unit mass rate of air flow increases as the combustion-chamber discharge temperature increases. For minimum specific fuel consumption, however, an optimum combustion-chamber discharge temperature exists, which in some cases may be less than the limiting temperature imposed by the strength temperature characteristics of present materials.

[Effects of different drying methods on processing performance and quality in bulbus of Tulipa edulis].

PubMed

Yang, Xiao-hua; Guo, Qiao-sheng; Zhu, Zai-biao; Chen, Jun; Miao, Yuan-yuan; Yang, Ying; Sun, Yuan

2015-10-01

Effects of different drying methods including sun drying, steamed, boiled, constant temperature drying (at 40, 50, 60 °C) on appearance, hardness, rehydration ratio, dry rate, moisture, total ash, extractive and polysaccharides contents were studied to provide the basis of standard processing method for Tulipa edulis bulbus. The results showed that the treatments of sun drying and 40 °C drying showed higher rehydration ratios, but lower dry rate, higher hardness, worse color, longer time and obvious distortion and shrinkage in comparison with other drying methods. The treatments of 60 °C constant temperature drying resulted in shorter drying time, lower water and higher polysaccharides content. Drying time is shorter and appearance quality is better in the treatment of steaming and boiling compared with other treatments, but the content of extractive and polysaccharides decreased significantly. The treatments of 50 °C constant temperature drying led to similar appearance quality of bulb to commercial bulb, and it resulted in lowest hardness and highest dry rate as well as higher rehydration ratio, extractive and polysaccharides content, moderate moisture and total ash contents among these treatments. Based on the results obtained, 50 °C constant temperature drying is the better way for the processing of T. edulis bulbus.

Program to develop a performance and heat load prediction system for multistage turbines

NASA Technical Reports Server (NTRS)

Sharma, OM

1994-01-01

Flows in low-aspect ratio turbines, such as the SSME fuel turbine, are three dimensional and highly unsteady due to the relative motion of adjacent airfoil rows and the circumferential and spanwise gradients in total pressure and temperature, The systems used to design these machines, however, are based on the assumption that the flow is steady. The codes utilized in these design systems are calibrated against turbine rig and engine data through the use of empirical correlations and experience factors. For high aspect ratio turbines, these codes yield reasonably accurate estimates of flow and temperature distributions. However, future design trends will see lower aspect ratio (reduced number of parts) and higher inlet temperature which will result in increased three dimensionality and flow unsteadiness in turbines. Analysis of recently acquired data indicate that temperature streaks and secondary flows generated in combustors and up-stream airfoils can have a large impact on the time-averaged temperature and angle distributions in downstream airfoil rows.

Pollutant emissions from flat-flame burners at high pressures

NASA Technical Reports Server (NTRS)

Maahs, H. G.; Miller, I. M.

1980-01-01

Maximum flame temperatures and pollutant emission measurements for NOx, CO, and UHC (unburned hydrocarbons) are reported for premixed methane air flat flames at constant total mass flow rate over the pressure range from 1.9 to 30 atm and for equivalence ratios from 0.84 to 1.12. For any given pressure, maxima typically occur in both the temperature and NOx emissions curves slightly to the lean side of stoichiometric conditions. The UHC emissions show minima at roughly the same equivalence ratios. The CO emissions, however, increase continually with increasing equivalence ratio. Flame temperature and NOx emissions decrease with increasing pressure, while the opposite is true for the CO and UHC emissions. The NOx data correlate reasonably well as a function of flame temperature only. Four flameholders, differing only slightly, were used. In general, the temperature and emissions data from these four flameholders are similar, but some differences also exist. These differences appear to be related to minor variations in the condition of the flameholder surfaces.

Propellant vaporization as a criterion for rocket-engine design : experimental effect of fuel temperature on liquid-oxygen - heptane performance

NASA Technical Reports Server (NTRS)

Heidmann, M F

1957-01-01

Characteristic exhaust velocity of a 200-pound-thrust rocket engine was evaluated for fuel temperatures of -90 degrees, and 200 degrees f with a spray formed by two impinging heptane jets reacting in a highly atomized oxygen atmosphere. Tests covered a range of mixture ratios and chamber lengths. The characteristic exhaust-velocity efficiency increased 2 percent for a 290 degree f increase in fuel temperature. This increase in performance can be compared with that obtained by increasing chamber length by about 1/2 inch. The result agrees with the fuel-temperature effect predicted from an analysis based on droplet evaporation theory. Mixture ratio markedly affected characteristic exhaust velocity efficiency, but total flow rate and fuel temperature did not.

NATO Standardization and Licensing Policy-Exploratory Phase. Volume 3. Supplement

DTIC Science & Technology

1976-11-30

Aerospatiale will perform at least half the production of this aircraft.* The concept involves a relatively light- weight advanced interceptor with...a ratio of total thrust to takeoff gross weight of about unity. The technology of the aircraft calls for the use of carbon fiber in selected...presenting a system with operating temperatures, pressure ratios, and thrust-to- weight ratios roughly comparable to U.S. technology. The

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

Dong Sun Lee; Yu Ryang Pyun

A food drying process in a tunnel dryer was modeled from Keey's drying model and experimental drying curve, and optimized in operating conditions consisting of inlet air temperature, air recycle ratio and air flow rate. Radish was chosen as a typical food material to be dried, because it has the typical drying characteristics of food and quality indexes of ascorbic acid destruction and browning during drying. Optimization results of cocurrent and counter current tunnel drying showed higher inlet air temperature, lower recycle ratio and higher air flow rate with shorter total drying time. Compared with cocurrent operation counter current dryingmore » used lower air temperature, lower recycle ratio and lower air flow rate, and appeared to be more efficient in energy usage. Most of consumed energy was shown to be used for sir heating and then escaped from the dryer in the form of exhaust air.« less

A distinct seasonal pattern of the ratio of soil respiration to total ecosystem respiration in a spruce-dominated forest

Treesearch

E.A. Davidson; A.D. Richardson; K.E. Savage; D.Y. Hollinger

2006-01-01

Annual budgets and fitted temperature response curves for soil respiration and ecosystem respiration provide useful information for partitioning annual carbon budgets of ecosystems, but they may not adequately reveal seasonal variation in the ratios of these two fluxes. Soil respiration (Rs) typically contributes 30-80% of...

An investigation of thermal changes of various permanent dental cements.

PubMed

Duymus, Zeynep Yesil; Yilmaz, Baykal; Karaalioglu, F Osman

2009-05-01

The aim of this study was to investigate and compare the temperature rises which occurred during the setting reactions of different permanent cements used to lute fixed partial prosthodontics. In this study, four cements were used. They were mixed in three different proportions: according to manufacturers' recommendations, at doubled powder ratio, and at doubled liquid ratio. With a thermocouple, the temperature rises which occurred during the setting reactions were measured. For each proportion, the measurement was repeated five times such that a total of 60 measurements were done for the four different cements. Data were analyzed using analysis of variance (ANOVA). ANOVA results showed that cement type and the interaction between cement type and the powder-liquid ratio were statistically significant factors (p<0.001). Similarly, the powder-liquid ratio was a statistically significant (p<0.01) factor. Among the dental cements tested, zinc phosphate cement showed the highest temperature rise during setting reaction, whereas glass ionomer cement showed the lowest.

A novel method for computing effective diffusivity: Application to helium implanted α-Fe thin films

NASA Astrophysics Data System (ADS)

Dunn, Aaron; Agudo-Merida, Laura; Martin-Bragado, Ignacio; McPhie, Mathieu; Cherkaoui, Mohammed; Capolungo, Laurent

2014-05-01

The effective diffusivity of helium in thin iron films is quantified using spatially resolved stochastic cluster dynamics and object kinetic Monte Carlo simulations. The roles of total displacement dose (in DPA), damage rate, helium to DPA ratio, layer thickness, and damage type (cascade damage vs Frenkel pair implantation) on effective He diffusivity are investigated. Helium diffusivity is found to decrease with increasing total damage and decreasing damage rate. Arrhenius plots show strongly increased helium diffusivity at high temperatures, high total implantation, and low implantation rates due to decreased vacancy and vacancy cluster concentrations. At low temperatures, effective diffusivity is weakly dependent on foil thickness while at high temperatures, narrower foils prevent defect accumulation by releasing all defects at the free surfaces. Helium to DPA ratio is not shown to strongly change helium diffusivity in the range of irradiation conditions simulated. Frenkel pair implantation is shown to cause higher effective diffusivity and more complex diffusion mechanisms than cascade implantation. The results of these simulations indicate that the differences in damage rates between implantation experiments and fission or fusion environments may result in differences in the final microstructure.

[Control strategies of nitrogen removal process in a pilot test of the southern WWTP based on the nitrogen balance].

PubMed

Jiang, Ying-He; Liu, Pei-Ju; Wang, Lei; Tian, Zhong-Kai; Liu, Xiao-Ying

2014-04-01

By building the mass balance of nitrogen in A2/O process, the nitrogen model which raised some strategies on how to control sludge return ratio and mixed liquid return ratio to make the effluent nitrogen achieve the national standard A under different influent total nitrogen (TN) , was set up. And the presumed parameters were verified by the pilot test of the Wuhan's Longwangzui WWTP. The result showed that when the temperature and the TN were over 15 degrees C and below 30 mg x L(-1) respectively, the mixed liquid return ratio was 0. When the temperature was between 10 degrees C and 15 degrees C and TN was over 30 mg x L(-1), higher MLSS and DO elevated N removal. When the temperature was far below 10 degrees C, the mixed liquid return ratio was also at a higher level. Based on the Wuhan's Longwangzui WWTP influent water quality, measures of adjusting the return ratio were well adapted to obtain acceptable nitrogen effluent.

[Effects of different NO3--N/NH4+-N ratios on cucumber seedlings growth, nitrogen absorption and metabolism under suboptimal temperature and light intensity].

PubMed

Zhang, Xiao Cui; Liu, Yu Mei; Bai, Long Qiang; He, Chao Xing; Yu, Xian Chang; Li, Yan Su

2016-08-01

Cucumber (cv. Zhongnong 26) was used as material, the effects of NO 3 - -N/NH 4 + -N ratios on growth and physiological characteristics of cucumber seedlings under suboptimal temperature and light intensity (18 ℃/10 ℃,180 ± 20 μmol·m -2 ·s -1 ) were studied. Total nitrogen in the nutrient solution was equal and three NO 3 - -N/NH 4 + -N ratios, 26:2, 21:7 and 14:14, were applied as treatments. The results showed that cucumber treated by NO 3 - -N/NH 4 + -N=21:7 had the longest total root length, the biggest root volume and root surface area, and the maximum number of root tips. H + -ATPase activity and relative expression of genes encoding nitrate transporter (NRT) and ammonium transporter (AMT) in cucumber roots were increased significantly by the treatment of NO 3 - -N/NH 4 + -N=21:7. In addition, nitrate reductase (NR), glutamine synthetase (GS) and glutamate synthase (GOGAT) in cucumber leaves under the treatment of NO 3 - -N/NH 4 + -N=21:7 were higher. As a result, the nitrogen content and biomass of cucumber were significantly increased. Compared with the plants under the treatment of NO 3 - -N/NH 4 + -N=26:2 or 14:14, cucumber seedlings under the treatment of NO 3 - -N/NH 4 + -N=21:7 had the highest biomass and total dry mass (DM) which were increased by 14.0% and 19.3% respectively under suboptimal temperature and light intensity. In conclusion, under suboptimal environmental conditions, NO 3 - -N/NH 4 + -N ratio could be adjusted to increase nitrogen absorption and metabolism of cucumber and alleviate the de-trimental effects caused by suboptimal conditions and promoted the cucumber growth.

Modeling Allometric Relationships in Leaves of Young Rapeseed (Brassica napus L.) Grown at Different Temperature Treatments

PubMed Central

Tian, Tian; Wu, Lingtong; Henke, Michael; Ali, Basharat; Zhou, Weijun; Buck-Sorlin, Gerhard

2017-01-01

Functional–structural plant modeling (FSPM) is a fast and dynamic method to predict plant growth under varying environmental conditions. Temperature is a primary factor affecting the rate of plant development. In the present study, we used three different temperature treatments (10/14°C, 18/22°C, and 26/30°C) to test the effect of temperature on growth and development of rapeseed (Brassica napus L.) seedlings. Plants were sampled at regular intervals (every 3 days) to obtain growth data during the length of the experiment (1 month in total). Total leaf dry mass, leaf area, leaf mass per area (LMA), width-length ratio, and the ratio of petiole length to leaf blade length (PBR), were determined and statistically analyzed, and contributed to a morphometric database. LMA under high temperature was significantly smaller than LMA under medium and low temperature, while leaves at high temperature were significantly broader. An FSPM of rapeseed seedlings featuring a growth function used for leaf extension and biomass accumulation was implemented by combining measurement with literature data. The model delivered new insights into growth and development dynamics of winter oilseed rape seedlings. The present version of the model mainly focuses on the growth of plant leaves. However, future extensions of the model could be used in practice to better predict plant growth in spring and potential cold damage of the crop. PMID:28377775

Heat transfer and pressure measurements for the SSME fuel turbine

NASA Technical Reports Server (NTRS)

Dunn, Michael G.; Kim, Jungho

1991-01-01

A measurement program is underway using the Rocketdyne two-stage Space Shuttle Main Engine (SSME) fuel turbine. The measurements use a very large shock tunnel to produce a short-duration source of heated and pressurized gas which is subsequently passed through the turbine. Within this environment, the turbine is operated at the design values of flow function, stage pressure ratio, stage temperature ratio, and corrected speed. The first stage vane row and the first stage blade row are instrumented in both the spanwise and chordwise directions with pressure transducers and heat flux gages. The specific measurements to be taken include time averaged surface pressure and heat flux distributions on the vane and blade, flow passage static pressure, flow passage total pressure and total temperature distributions, and phase resolved surface pressure and heat flux on the blade.

Human local and total heat losses in different temperature.

PubMed

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

2016-04-01

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

On the Fast Evaluation Method of Temperature and Gas Mixing Ratio Weighting Functions for Remote Sensing of Planetary Atmospheres in Thermal IR and Microwave

NASA Technical Reports Server (NTRS)

Ustinov, E. A.

1999-01-01

Evaluation of weighting functions in the atmospheric remote sensing is usually the most computer-intensive part of the inversion algorithms. We present an analytic approach to computations of temperature and mixing ratio weighting functions that is based on our previous results but the resulting expressions use the intermediate variables that are generated in computations of observable radiances themselves. Upwelling radiances at the given level in the atmosphere and atmospheric transmittances from space to the given level are combined with local values of the total absorption coefficient and its components due to absorption of atmospheric constituents under study. This makes it possible to evaluate the temperature and mixing ratio weighting functions in parallel with evaluation of radiances. This substantially decreases the computer time required for evaluation of weighting functions. Implications for the nadir and limb viewing geometries are discussed.

Evaporation and condensation at a liquid surface. I. Argon

NASA Astrophysics Data System (ADS)

Yasuoka, Kenji; Matsumoto, Mitsuhiro; Kataoka, Yosuke

1994-11-01

Molecular dynamics computer simulations were carried out to investigate the dynamics of evaporation and condensation for argon at the temperature of 80 and 100 K. From the decrease of the survival probability of vapor molecules, the ratio of self reflection to collision is estimated to be 12%-15%, only weakly dependent on the temperature. This suggests that argon vapor molecules are in the condition of almost complete capture, and the condensation is considered to be a barrierless process. The total ratio of reflection which is evaluated with the flux correlation of condensation and evaporation is 20% at both temperature. The difference between these two ratios of reflection is ascribed to a phenomenon that vapor molecules colliding with the surface drive out other liquid molecules. This molecule exchange at the surface is as important as the self-reflection, and the conventional picture of condensation as a unimolecular chemical reaction is not appropriate.

Computer program for preliminary design analysis of axial-flow turbines

NASA Technical Reports Server (NTRS)

Glassman, A. J.

1972-01-01

The program method is based on a mean-diameter flow analysis. Input design requirements include power or pressure ratio, flow, temperature, pressure, and speed. Turbine designs are generated for any specified number of stages and for any of three types of velocity diagrams (symmetrical, zero exit swirl, or impulse). Exit turning vanes can be included in the design. Program output includes inlet and exit annulus dimensions, exit temperature and pressure, total and static efficiencies, blading angles, and last-stage critical velocity ratios. The report presents the analysis method, a description of input and output with sample cases, and the program listing.

Preliminary tests of an advanced high-temperature combustion system

NASA Technical Reports Server (NTRS)

Wear, J. D.; Trout, A. M.; Smith, J. M.; Jacobs, R. E.

1983-01-01

A combustion system has been developed to operate efficiently and with good durability at inlet pressures to 4.05 MPa (40 atm), inlet air temperatures to 900 K, and exhaust gas temperatures to 2480 K. A preliminary investigation of this system was conducted at inlet pressures to 0.94 MPa (9 atm), a nominal inlet air temperature of 560 K, and exhaust gas temperatures to 2135 K. A maximum combustion efficiency of 98.5 percent was attained at a fuel-air ratio of 0.033; the combustion efficiency decreased to about 90 percent as the fuel-air ratio was increased to 0.058. An average liner metal temperature of 915 K, 355 kelvins greater than the nominal inlet air temperature, was reached with an average exhaust gas temperature of 2090 K. The maximum local metal temperature at this condition was about 565 kelvins above the nominal inlet air temperature and decreased to 505 kelvins above with increasing combustor pressure. Tests to determine the isothermal total pressure loss of the combustor showed a liner loss of 1.1 percent and a system loss of 6.5 percent.

The effect of temperature and drawing ratio on the mechanical properties of polypropylene monofilaments

NASA Astrophysics Data System (ADS)

Taheri, Hesam; Nóbrega, João Miguel; Samyn, Pieter; Covas, José Antonio

2014-05-01

In this work, the simultaneous effect of both temperature and drawing ratio during processing of polypropylene monofilaments has been investigated. The basis of this work specifically aims at emphasizing the conditions of temperature and drawing ratio applied in the cooling bath, in order to find out under which conditions the named parameters can be applied in a processing line under continuous extrusion. The effects of temperature are studied for a constant total drawing ratio to analyze the influences on mechanical properties and structural differences of the final polypropylene monofilament. The quenched monofilaments were drawn around an adjustable guide assembly in the quench bath and first drawing stage, imparting thermal and mechanical treatments to the filaments. In the heating stage, monofilaments are affected to high-speed draw rolls while passing through the oven. As such, the best conditions to produce a polypropylene monofilament with high tenacity strength were determined. Results of this study show that the monofilament properties are significantly affected by temperature in the cooling zone. The nature of the first drawing had a significant effect on the end properties and monofilaments with modulus of 637 MPa have finally been manufactured. We have also proposed a new hypothesis, which is termed "gap nucleation" and determine this phenomenon in the gap between die and cooling bath.

Application and Analysis of the Isoelectronic Line Ratio Temperature Diagnostic in a Planar Ablating-Plasma Experiment at the National Ignition Facility

NASA Astrophysics Data System (ADS)

Epstein, R.; Rosenberg, M. J.; Solodov, A. A.; Myatt, J. F.; Regan, S. P.; Seka, W.; Hohenberger, M.; Barrios, M. A.; Moody, J. D.

2015-11-01

The Mn/Co isoelectronic emission-line ratio from a microdot source in planar CH foil targets was measured to infer the electron temperature (Te) in the ablating plasma during two-plasmon-decay experiments at the National Ignition Facility (NIF). We examine the systematic uncertainty in the Te estimate based on the temperature and density sensitivities of the line ratio in conjunction with plausible density constraints, and its contribution to the total Te estimate uncertainty. The potential advantages of alternative microdot elements (e.g., Ti/Cr and Sc/V) are considered. The microdot mass was selected to provide ample line strength while minimizing the effect of self-absorption on the line emission, which is of particular concern, given the narrow linewidths of mid- Z emitters at subcritical electron densities. Atomic line-formation theory and detailed atomic-radiative simulations show that the straight forward interpretation of the isoelectronic ratio solely in terms of its temperature independence remains valid with lines of moderate optical thickness (up to ~ 10) at line center. This material is based upon work supported by the Department of Energy National Nuclear Security Administration under Award Number DE-NA0001944.

Emission measures derived from far ultraviolet spectra of T Tauri stars

NASA Astrophysics Data System (ADS)

Cram, L. E.; Giampapa, M. S.; Imhoff, C. L.

1980-06-01

Spectroscopic diagnostics based on UV emission line observations have been developed to study the solar chromosphere, transition region, and corona. The atmospheric properties that can be inferred from observations of total line intensities include the temperature, by identifying the ionic species present; the temperature distribution of the emission measure, from the absolute intensities; and the electron density of the source, from line intensity ratios sensitive to the electron density. In the present paper, the temperature distribution of the emission measure is estimated from observations of far UV emission line fluxes of the T Tauri stars, RW Aurigae and RU Lupi, made on the IUE. A crude estimate of the electron density of one star is obtained, using density-sensitive line ratios.

High Temperature Reactions of Uranium Dioxide with Various Metal Oxides

DTIC Science & Technology

1956-02-20

manganese, nickel , lead, and tin. Subtracting the total of these impurities from the oxygen remainder would give a more nearly 1:2 uranium -oxygen ratio. The...Astin, Dire~ctor High -Temperature Reactions of Uranium Dioxide With Various Metal Oxides Acceson For NTIS CRAWI DTfC TAB Unannounced D JustifiCation...1 2. The uranium -oxygen system ------------------------------------- 1 3. Binary systems containing

Characteristics of Mach 10 transitional and turbulent boundary layers

NASA Technical Reports Server (NTRS)

Watson, R. D.

1978-01-01

Measurements of the mean flow properties of transitional and turbulent boundary layers in helium on 4 deg and 5 deg wedges were made for flows with edge Mach numbers from 9.5 to 11.3, ratios of wall temperature to total temperature of 0.4 to 0.95, and maximum length Reynolds numbers of one hundred million. The data include pitot and total temperature surveys and measurements of heat transfer and surface shear. In addition, with the assumption of local similarity, turbulence quantities such as the mixing length were derived from the mean flow profiles. Low Reynolds number and precursor transition effects were significant factors at these test conditions and were included in finite difference boundary layer predictions.

Transition of the Laminar Boundary Layer on a Delta Wing with 74 degree Sweep in Free Flight at Mach Numbers from 2.8 to 5.3

NASA Technical Reports Server (NTRS)

Chapman, Gary T.

1961-01-01

The tests were conducted at Mach numbers from 2.8 to 5.3, with model surface temperatures small compared to boundary-layer recovery temperature. The effects of Mach number, temperature ratio, unit Reynolds number, leading-edge diameter, and angle of attack were investigated in an exploratory fashion. The effect of heat-transfer condition (i.e., wall temperature to total temperature ratio) and Mach number can not be separated explicitly in free-flight tests. However, the data of the present report, as well as those of NACA TN 3473, were found to be more consistent when plotted versus temperature ratio. Decreasing temperature ratio increased the transition Reynolds number. The effect of unit Reynolds number was small as was the effect of leading-edge diameter within the range tested. At small values of angle of attack, transition moved forward on the windward surface and rearward on the leeward surface. This trend was reversed at high angles of attack (6 deg to 18 deg). Possible reasons for this are the reduction of crossflow on the windward side and the influence of the lifting vortices on the leeward surface. When the transition results on the 740 delta wing were compared to data at similar test conditions for an unswept leading edge, the results bore out the results of earlier research at nearly zero heat transfer; namely, sweep causes a large reduction in the transition Reynolds number.

Enzymatic production of infant milk fat analogs containing palmitic acid: optimization of reactions by response surface methodology.

PubMed

Maduko, C O; Akoh, C C; Park, Y W

2007-05-01

Infant milk fat analogs resembling human milk fat were synthesized by an enzymatic interesterification between tripalmitin, coconut oil, safflower oil, and soybean oil in hexane. A commercially immobilized 1,3-specific lipase, Lipozyme RM IM, obtained from Rhizomucor miehei was used as a biocatalyst. The effects of substrate molar ratio, reaction time, and incubation temperature on the incorporation of palmitic acid at the sn-2 position of the triacylglycerols were investigated. A central composite design with 5 levels and 3 factors consisting of substrate ratio, reaction temperature, and incubation time was used to model and optimize the reaction conditions using response surface methodology. A quadratic model using multiple regressions was then obtained for the incorporation of palmitic acid at the sn-2 positions of glycerols as the response. The coefficient of determination (R2) value for the model was 0.845. The incorporation of palmitic acid appeared to increase with the decrease in substrate molar ratio and increase in reaction temperature, and optimum incubation time occurred at 18 h. The optimal conditions generated from the model for the targeted 40% palmitic acid incorporation at the sn-2 position were 3 mol/mol, 14.4 h, and 55 degrees C; and 2.8 mol/mol, 19.6 h, and 55 degrees C for substrate ratio (moles of total fatty acid/moles of tripalmitin), time, and temperature, respectively. Infant milk fat containing fatty acid composition and sn-2 fatty acid profile similar to human milk fat was successfully produced. The fat analogs produced under optimal conditions had total and sn-2 positional palmitic acid levels comparable to that of human milk fat.

Dry fermentation of agricultural residues

NASA Astrophysics Data System (ADS)

Jewell, W. J.; Chandler, J. A.; Dellorto, S.; Fanfoni, K. J.; Fast, S.; Jackson, D.; Kabrick, R. M.

1981-09-01

A dry fermentation process is discussed which converts agricultural residues to methane, using the residues in their as produced state. The process appears to simplify and enhance the possibilities for using crop residues as an energy source. The major process variables investigated include temperature, the amount and type of inoculum, buffer requirements, compaction, and pretreatment to control the initial available organic components that create pH problems. A pilot-scale reactor operation on corn stover at a temperature of 550 C, with 25 percent initial total solids, a seed-to-feed ratio of 2.5 percent, and a buffer-to-feed ratio of 8 percent achieved 33 percent total volatile solids destruction in 60 days. Volumetric biogas yields from this unit were greater than 1 vol/vol day for 12 days, and greater than 0.5 vol/vol day for 32 days, at a substrate density of 169 kg/m (3).

Evaporation and condensation at a liquid surface. II. Methanol

NASA Astrophysics Data System (ADS)

Matsumoto, Mitsuhiro; Yasuoka, Kenji; Kataoka, Yosuke

1994-11-01

The rates of evaporation and condensation of methanol under the vapor-liquid equilibrium condition at the temperature of 300 and 350 K are investigated with a molecular dynamics computer simulation. Compared with the argon system (reported in part I), the ratio of self-reflection is similar (˜10%), but the ratio of molecule exchange is several times larger than the argon, which suggests that the conventional assumption of condensation as a unimolecular process completely fails for associating fluids. The resulting total condensation coefficient is 20%-25%, and has a quantitative agreement with a recent experiment. The temperature dependence of the evaporation-condensation behavior is not significant.

Oxygen stable isotope ratios from British oak tree-rings provide a strong and consistent record of past changes in summer rainfall

NASA Astrophysics Data System (ADS)

Young, Giles H. F.; Loader, Neil J.; McCarroll, Danny; Bale, Roderick J.; Demmler, Joanne C.; Miles, Daniel; Nayling, Nigel T.; Rinne, Katja T.; Robertson, Iain; Watts, Camilla; Whitney, Matthew

2015-12-01

United Kingdom (UK) summers dominated by anti-cyclonic circulation patterns are characterised by clear skies, warm temperatures, low precipitation totals, low air humidity and more enriched oxygen isotope ratios (δ18O) in precipitation. Such conditions usually result in relatively more positive (enriched) oxygen isotope ratios in tree leaf sugars and ultimately in the tree-ring cellulose formed in that year, the converse being true in cooler, wet summers dominated by westerly air flow and cyclonic conditions. There should therefore be a strong link between tree-ring δ18O and the amount of summer precipitation. Stable oxygen isotope ratios from the latewood cellulose of 40 oak trees sampled at eight locations across Great Britain produce a mean δ18O chronology that correlates strongly and significantly with summer indices of total shear vorticity, surface air pressure, and the amount of summer precipitation across the England and Wales region of the United Kingdom. The isotope-based rainfall signal is stronger and much more stable over time than reconstructions based upon oak ring widths. Using recently developed methods that are precise, efficient and highly cost-effective it is possible to measure both carbon (δ13C) and oxygen (δ18O) isotope ratios simultaneously from the same tree-ring cellulose. In our study region, these two measurements from multiple trees can be used to reconstruct summer temperature (δ13C) and summer precipitation (δ18O) with sufficient independence to allow the evolution of these climate parameters to be reconstructed with high levels of confidence. The existence of long, well-replicated oak tree-ring chronologies across the British Isles mean that it should now be possible to reconstruct both summer temperature and precipitation over many centuries and potentially millennia.

Nano ZSM-5 type ferrisilicates as novel catalysts for ethylbenzene dehydrogenation in the presence of N 2O

NASA Astrophysics Data System (ADS)

Khatamian, M.; Khandar, A. A.; Haghighi, M.; Ghadiri, M.

2011-11-01

Nanosized ZSM-5 type ferrisilicates were successfully prepared using hydrothermal process. Several parameters including gel initiative compositions (Na+ or K+ alkali system), SiO2/Fe2O3 molar ratios and hydrothermal temperature were systematically investigated. The samples were characterized by XRD, TEM, SEM-EDS, BET surface area and ICP techniques. It was found that surface areas and the total pore volume increase with increasing in the SiO2/Fe2O3 molar ratio at Na-FZ ferrisilicates. The catalytic performance of the synthesized catalysts was evaluated in ethylbenzene dehydrogenation to styrene in the presence of N2O or steam at temperatures ranging from 400 °C to 660 °C under atmospheric pressure. The effects of gel initiative compositions, SiO2/Fe2O3 molar ratio as well as the hydrothermal synthesis temperature on the catalytic performance of these catalysts have been addressed. It was shown that styrene yield significantly influenced by altering in the SiO2/Fe2O3 ratio but was not greatly influenced by changes in hydrothermal synthesis temperatures. The comparison between performance of potassium and sodium containing catalysts was shown that the one with potassium has higher yield and selectivity toward styrene production at an optimum temperature of 610 °C.

Metabolic heating and the prediction of sex ratios for green turtles (Chelonia mydas).

PubMed

Broderick, A C; Godley, B J; Hays, G C

2001-01-01

We compared incubation temperatures in nests (n=32) of the green turtle (Chelonia mydas) on Ascension Island in relation to sand temperatures of control sites at nest depth. Intrabeach thermal variation was low, whereas interbeach thermal variation was high in both control and nest sites. A marked rise in temperature was recorded in nests from 30% to 40% of the way through the incubation period and attributed to metabolic heating. Over the entire incubation period, metabolic heating accounted for a mean rise in temperature of between 0.07 degrees and 2.86 degrees C within nests. During the middle third of incubation, when sex is thought to be determined, this rise in temperature ranged between 0.07 degrees and 2.61 degrees C. Metabolic heating was related to both the number of eggs laid and the total number of hatchlings/embryos produced in a clutch. For 32 clutches in which temperature was recorded, we estimate that metabolic heating accounted for a rise of up to 30% in the proportion of females produced within different clutches. Previous studies have dismissed any effect of metabolic heating on the sex ratio of marine turtle hatchlings. Our results imply that metabolic heating needs to be considered when estimating green turtle hatchling sex ratios.

Character change of New England snow

USGS Publications Warehouse

Huntington, T.G.; Hodgkins, G.A.; Keim, B.D.; Dudley, R.W.

2004-01-01

The annual ratio of snow to total precipitation (S/P) for 11 out of 21 US Historical Climatology Network (USHCN) sites in New England decreased significantly from 1949 through 2000. One possible explanation for the observed decrease in S/P ratio is that their temperature increased in New England during the 20th century. The results are consistent with published reports indicating lengthening of the growing season in New England.

High Variability in Cellular Stoichiometry of Carbon, Nitrogen, and Phosphorus Within Classes of Marine Eukaryotic Phytoplankton Under Sufficient Nutrient Conditions.

PubMed

Garcia, Nathan S; Sexton, Julie; Riggins, Tracey; Brown, Jeff; Lomas, Michael W; Martiny, Adam C

2018-01-01

Current hypotheses suggest that cellular elemental stoichiometry of marine eukaryotic phytoplankton such as the ratios of cellular carbon:nitrogen:phosphorus (C:N:P) vary between phylogenetic groups. To investigate how phylogenetic structure, cell volume, growth rate, and temperature interact to affect the cellular elemental stoichiometry of marine eukaryotic phytoplankton, we examined the C:N:P composition in 30 isolates across 7 classes of marine phytoplankton that were grown with a sufficient supply of nutrients and nitrate as the nitrogen source. The isolates covered a wide range in cell volume (5 orders of magnitude), growth rate (<0.01-0.9 d -1 ), and habitat temperature (2-24°C). Our analysis indicates that C:N:P is highly variable, with statistical model residuals accounting for over half of the total variance and no relationship between phylogeny and elemental stoichiometry. Furthermore, our data indicated that variability in C:P, N:P, and C:N within Bacillariophyceae (diatoms) was as high as that among all of the isolates that we examined. In addition, a linear statistical model identified a positive relationship between diatom cell volume and C:P and N:P. Among all of the isolates that we examined, the statistical model identified temperature as a significant factor, consistent with the temperature-dependent translation efficiency model, but temperature only explained 5% of the total statistical model variance. While some of our results support data from previous field studies, the high variability of elemental ratios within Bacillariophyceae contradicts previous work that suggests that this cosmopolitan group of microalgae has consistently low C:P and N:P ratios in comparison with other groups.

Fermentation optimization of goat milk with Lactobacillus acidophilus and Bifidobacterium bifidum by Box-Behnken design.

PubMed

Shu, Guowei; Bao, Chunju; Chen, He; Wang, Changfeng; Yang, Hui

2016-01-01

Goat milk is only limited to the processing of goat milk powder and liquid milk, the products are mainly about milk powder and a few of them are made as milk tablet. Therefore, the study of probiotic goat milk will have great significance in the full use of goats and the development of the goat milk industry in China. The effect of fermentation temperature (35°C, 37°C, 39°C), strain ratio (1:1:1, 2:1:1, 3:1:1) and inoculum size (4%, 5%, 6%) on viable counts of L. acidophilus and B. bifidum, total bacteria and sensory value during fermentation process of L. acidophilus and B. bifidum goat yogurt (AB-goat yogurt) was investigated. The optimum fermentation conditions for AB-goat yogurt were: fermentation temperature 38°C, the strain ratio 2:1:1, inoculum size 6%. Under the optimum conditions, the viable counts of B. bifidum, L. acidophilus, total bacteria and sensory value reached (4.30 ±0.11)×107  cfu/mL, (1.39 ±0.09)×108  cfu/mL, (1.82±0.06)×109  cfu/mL and 7.90 ±0.14, respectively. The fermentation temperature, the strain ratio and inoculum size had a significant effect on the fermentation of AB-goat yogurt and these results are beneficial for developing AB-goat yogurt.

Roles of predation, food, and temperature in structuring the epilimnetic zooplankton populations in Lake Ontario, 1981-1986

USGS Publications Warehouse

Johannsson, Ora E.; O'Gorman, Robert

1991-01-01

We sampled phytoplankton, zooplankton, and alewives Alosa pseudoharengus and measured water temperature in Lake Ontario during 1981–1986. Through the use of general linear regression models we then sought evidence of control of the eplimnetic zooplankton community (mid-July to mid-October) by producers, consumers, and temperature. Our measures of the zooplankton community were total biomass, cladoceran biomass, and the ratio of large to small Daphnia spp. (D. galeata mendotae andD. retrocurva). Zooplankton population variables assessed were abundance, egg ratio, and productivity. Through factor analysis, factors were created from the standardized, transformed independent variables for use in the regression analyses. Regression models showed significant inverse relationships (P < 0.05) between alewives and Bosmina longirostris (abundance, production, and egg ratio), Ceriodaphnia lacustris (egg ratio), andDaphnia retrocurva (egg ratio). Bosmina longirostris and D. retrocurva egg ratios were inversely related to algae biomass (<20 μm), thus the smaller algae might be controlled in part by the zooplankton community. Production of C. lacustris was directly related to temperature, as was the production and abundance of Tropocyclops prasinus. The annual size-frequency distributions of B. longirostris and D. retrocurva were inversely related to yearling alewife abundance and directly related to adult alewife abundance, which suggested that yearlings use a particulate-feeding mode on these zooplankton species more frequently than adults. We found no significant negative correlations among the zooplankton species, which suggested that interzooplankton predation and competition were not as important in structuring the community as were planktivory and temperature.

CO2 sequestration by mineral carbonation of steel slags under ambient temperature: parameters influence, and optimization.

PubMed

Ghacham, Alia Ben; Pasquier, Louis-César; Cecchi, Emmanuelle; Blais, Jean-François; Mercier, Guy

2016-09-01

This work focuses on the influence of different parameters on the efficiency of steel slag carbonation in slurry phase under ambient temperature. In the first part, a response surface methodology was used to identify the effect and the interactions of the gas pressure, liquid/solid (L/S) ratio, gas/liquid ratio (G/L), and reaction time on the CO2 removed/sample and to optimize the parameters. In the second part, the parameters' effect on the dissolution of CO2 and its conversion into carbonates were studied more in detail. The results show that the pressure and the G/L ratio have a positive effect on both the dissolution and the conversion of CO2. These results have been correlated with the higher CO2 mass introduced in the reactor. On the other hand, an important effect of the L/S ratio on the overall CO2 removal and more specifically on the carbonate precipitation has been identified. The best results were obtained L/S ratios of 4:1 and 10:1 with respectively 0.046 and 0.052 gCO2 carbonated/g sample. These yields were achieved after 10 min reaction, at ambient temperature, and 10.68 bar of total gas pressure following direct gas treatment.

Heat flow vs. atmospheric greenhouse on early Mars

NASA Technical Reports Server (NTRS)

Fanale, F. P.; Postawko, S. E.

1991-01-01

Researchers derived a quantitative relationship between the effectiveness of an atmospheric greenhouse and internal heat flow in producing the morphological differences between earlier and later Martian terrains. The derivation is based on relationships previously derived by other researchers. The reasoning may be stated as follows: the CO2 mean residence time in the Martian atmosphere is almost certainly much shorter than the total time span over which early climate differences are thought to have been sustained. Therefore, recycling of previously degassed CO2 quickly becomes more important than the ongoing supply of juvenile CO2. If so, then the atmospheric CO2 pressure, and thereby the surface temperature, may be approximated mathematically as a function of the total degassed CO2 in the atmosphere plus buried material and the ratio of the atmospheric and regolith mean residence times. The latter ratio can also be expressed as a function of heat flow. Hence, it follows that the surface temperature may be expressed as a function of heat flow and the total amount of available CO2. However, the depth to the water table can simultaneously be expressed as a function of heat flow and the surface temperature (the boundary condition). Therefore, for any given values of total available CO2 and regolith conductivity, there exist coupled independent equations which relate heat flow, surface temperature, and the depth to the water table. This means we can now derive simultaneous values of surface temperature and the depth of the water table for any value of the heat flow. The derived relationship is used to evaluate the relative importance of the atmospheric greenhouse effect and the internal regolith thermal gradient in producing morphological changes for any value of the heat flow, and to assess the absolute importance of each of the values of the heat flow which are thought to be reasonable on independent geophysical grounds.

Heat-Transfer Characteristics of Partially Film Cooled Plug Nozzle on a J-85 Afterburning Turbojet Engine

NASA Technical Reports Server (NTRS)

Nosek, S. M.; Straight, D. M.

1976-01-01

Plug nozzle film cooling data were obtained downstream of a slot located at 42 percent of the total plug length on a J-85 engine. Film cooling reduced the aft end wall temperature as much as 150 K, reduced total pressure loss in the upstream convection cooling passages by 50 percent, and reduced estimated compressor bleed flow requirement by 14 percent compared to an all convectively cooled nozzle. Shock waves along the plug surface strongly influenced temperature distributions on both convection and film cooled portions. The effect was most severe at nozzle pressure ratios below 10 where adverse pressure gradients were most severe.

Feasibility study of a V-shaped pipe for passive aeration composting.

PubMed

Ogunwande, Gbolabo A

2011-03-01

A V-shaped (Vs) pipe was improvised for composting of chicken litter in passive aeration piles. Three piles, equipped with horizontal (Ho), vertical (Ve) and Vs pipes were set up. The three treatments were replicated thrice. The effects of the aeration pipe on the physico-chemical properties of chicken litter and air distribution within the composting piles were investigated during composting. The properties monitored were temperature, pH, electrical conductivity, moisture content, total carbon, total nitrogen, total phosphorus and carbon-to-nitrogen ratio. Moisture level in the piles was replenished fortnightly to 60% during composting. The results of the study showed that all the piles attained the optimum temperature range (40-65°C) for effective composting and satisfied the requirements for sanitation. The non-significant (p > 0.05) temperature difference within the piles with Ve and Vs pipes indicated that these pipes were effective for uniform air distribution within the pile. The aeration pipe had significant (p ≤ 0.05) effect on pile temperature, pre-replenishment moisture content, pH and total phosphorus. In conclusion, the study showed that the Vs pipe is feasible and effective for passive aeration composting.

Performance of high-area-ratio annular dump diffuser using suction-stabilized-vortex flow control

NASA Technical Reports Server (NTRS)

Juhasz, A. J.; Smith, J. M.

1977-01-01

A short annular dump diffuser having a geometry conductive to formation of suction stabilized toroidal vortices in the region of abrupt area change was tested. The overall diffuser area ratio was 4.0 and the length to inlet height ratio was 2.0. Performance data were obtained at near ambient temperature and pressure for inlet Mach numbers of 0.18 and 0.30 with suction rates ranging from 0 to 18 percent of total inlet mass flowrate. Results show that the exit velocity profile could be readily biased toward either wall by adjustment of inner and outer wall suction rates. Symmetric exit velocity profiles were inherently unstable with a tendency to revert to a hub or tip bias. Diffuser effectiveness was increased from about 38 percent without suction to over 85 percent at a total suction rate of 10 to 12 percent. At the same time diffuser total pressure loss was reduced from 3.1 percent to 1.1 percent at an inlet Mach number of 0.3.

Effect of COD/SO4(2-) ratio on anaerobic treatment of landfill leachate during the start-up period.

PubMed

Yilmaz, Tuba; Erdirencelebi, Dilek; Berktay, Ali

2012-01-01

This study investigates the performance of an anaerobic baffled reactor (ABR) during the start-up period of raw young landfill leachate treatment at two chemical oxygen demand (COD) to SO4(2-) ratios of 20 and 4. The reactor was operated at ambient temperature and low organic loading rates (0.52, 0.76 and 1.05 kg COD/m3 per day). During the study, sulfate-reducing bacteria (SRB) activity increased at the lower ratio of COD/SO4(2-) producing higher levels of sulfide and alkalinity. The dissolved sulfide concentration reached an inhibitory level above 250 mg/L, which caused a sharp reduction in the total COD removal efficiency from 77-80% to 32%. Total volatile fatty acid (TVFA) production proceeded at a constant level despite increased organic loading. As the effluent total and organic COD concentrations increased, the inhibitory effect of the inborn sulfide was correlated to the limitation experienced in the hydrolysis/acidogenesis stages, and thus VFA production and organic matter removal.

Uterine fibroids: postsonication temperature decay rate enables prediction of therapeutic responses to MR imaging-guided high-intensity focused ultrasound ablation.

PubMed

Kim, Young-sun; Park, Min Jung; Keserci, Bilgin; Nurmilaukas, Kirsi; Köhler, Max O; Rhim, Hyunchul; Lim, Hyo Keun

2014-02-01

To determine whether intraprocedural thermal parameters as measured with magnetic resonance (MR) thermometry can be used to predict immediate or delayed therapeutic response after MR-guided high-intensity focused ultrasound (HIFU) ablation of uterine fibroids. Institutional review board approval and subject informed consent were obtained. A total of 105 symptomatic uterine fibroids (mean diameter, 8.0 cm; mean volume, 251.8 mL) in 71 women (mean age, 43.3 years; age range, 25-52 years) who underwent volumetric MR HIFU ablation were analyzed. Correlations between tumor-averaged intraprocedural thermal parameters (peak temperature, thermal dose efficiency [estimated volume of 240 equivalent minutes at 43°C divided by volume of treatment cells], and temperature decay rate after sonication) and the immediate ablation efficiency (ratio of nonperfused volume [NPV] at immediate follow-up to treatment cell volume) or ablation sustainability (ratio of NPV at 3-month follow-up to NPV at immediate follow-up) were assessed with linear regression analysis. A total of 2818 therapeutic sonications were analyzed. At immediate follow-up with MR imaging (n = 105), mean NPV-to-fibroid volume ratio and ablation efficiency were 0.68 ± 0.26 (standard deviation) and 1.35 ± 0.75, respectively. A greater thermal dose efficiency (B = 1.894, P < .001) and slower temperature decay rate (B = -1.589, P = .044) were independently significant factors that indicated better immediate ablation efficiency. At 3-month follow-up (n = 81), NPV had decreased to 43.1% ± 21.0 of the original volume, and only slower temperature decay rate was significantly associated with better ablation sustainability (B = -0.826, P = .041). The postsonication temperature decay rate enables prediction of both immediate and delayed therapeutic responses, whereas thermal dose efficiency enables prediction of immediate therapeutic response to MR HIFU ablation of uterine fibroids. © RSNA, 2013.

Extraction of natural anthocyanin and colors from pulp of jamun fruit.

PubMed

Maran, J Prakash; Sivakumar, V; Thirugnanasambandham, K; Sridhar, R

2015-06-01

In this present study, natural pigment and colors from pulp of jamun fruit were extracted under different extraction conditions such as extraction temperature (40-60 ˚C), time (20-100 min) and solid-liquid ratio (1:10-1: 15 g/ml) by aqueous extraction method. Three factors with three levels Box-Behnken response surface design was employed to optimize and investigate the effect of process variables on the responses (total anthocyanin and color). The results were analyzed by Pareto analysis of variance (ANOVA) and second order polynomial models were developed to predict the responses. Optimum extraction conditions for maximizing the extraction yield of total anthocyanin (10.58 mg/100 g) and colors (10618.3 mg/l) were found to be: extraction temperature of 44 °C, extraction time of 93 min and solid-liquid ratio of 1:15 g/ml. Under these conditions, experimental values are closely agreed with predicted values.

Research on shock wave characteristics in the isolator of central strut rocket-based combined cycle engine under Ma5.5

NASA Astrophysics Data System (ADS)

Wei, Xianggeng; Xue, Rui; Qin, Fei; Hu, Chunbo; He, Guoqiang

2017-11-01

A numerical calculation of shock wave characteristics in the isolator of central strut rocket-based combined cycle (RBCC) engine fueled by kerosene was carried out in this paper. A 3D numerical model was established by the DES method. The kerosene chemical kinetic model used the 9-component and 12-step simplified mechanism model. Effects of fuel equivalence ratio, inflow total temperature and central strut rocket on-off on shock wave characteristics were studied under Ma5.5. Results demonstrated that with the increase of equivalence ratio, the leading shock wave moves toward upstream, accompanied with higher possibility of the inlet unstart. However, the leading shock wave moves toward downstream as the inflow total temperature rises. After the central strut rocket is closed, the leading shock wave moves toward downstream, which can reduce risks of the inlet unstart. State of the shear layer formed by the strut rocket jet flow and inflow can influence the shock train structure significantly.

Effect of flame stabilizer design on performance and exhaust pollutants of a two-row 72-module swirl-can combustor

NASA Technical Reports Server (NTRS)

Biaglow, J. A.; Trout, A. M.

1976-01-01

A test program was conducted to evaluate the effects of four flame stabilizer designs on the performance and gaseous pollutant levels of an experimental full-annular swirl-can combustor. Combustor operating parameters, including inlet-air temperature, reference velocity, and fuel-air ratio, were set to simulate conditions in a 30:1 pressure ratio engine. Combustor inlet total pressure was held constant at 6 atm due to the facility limit. Combustor performance and gaseous pollutant levels were strongly affected by the geometry and resulting total pressure loss of the four flame stabilizer designs investigated. The addition of shrouds to two designs produced an 18 to 22% decrease in the combustion chamber pressure loss and thus resulted in doubling the exit temperature pattern factor and up to 42% higher levels of oxides of nitrogen. A previously developed oxides of nitrogen correlating parameter agreed with each model within an emission index of plus or minus 1 but was not capable of correlating all models together.

Study of 3D-growth conditions for selective area MOVPE of high aspect ratio GaN fins with non-polar vertical sidewalls

NASA Astrophysics Data System (ADS)

Hartmann, Jana; Steib, Frederik; Zhou, Hao; Ledig, Johannes; Nicolai, Lars; Fündling, Sönke; Schimpke, Tilman; Avramescu, Adrian; Varghese, Tansen; Trampert, Achim; Straßburg, Martin; Lugauer, Hans-Jürgen; Wehmann, Hergo-Heinrich; Waag, Andreas

2017-10-01

GaN fins are 3D architectures elongated in one direction parallel to the substrate surface. They have the geometry of walls with a large height to width ratio as well as small footprints. When appropriate symmetry directions of the GaN buffer are used, the sidewalls are formed by non-polar {1 1 -2 0} planes, making the fins particularly suitable for many device applications like LEDs, FETs, lasers, sensors or waveguides. The influence of growth parameters like temperature, pressure, V/III ratio and total precursor flow on the fin structures is analyzed. Based on these results, a 2-temperature-step-growth was developed, leading to fins with smooth side and top facets, fast vertical growth rates and good homogeneity along their length as well as over different mask patterns. For the core-shell growth of fin LED heterostructures, the 2-temperature-step-growth shows much smoother sidewalls and less crystal defects in the InGaN QW and p-GaN shell compared to structures with cores grown in just one step. Electroluminescence spectra of the 2-temperature-step-grown fin LED are demonstrated.

Application of OMI Observations to a Space-Based Indicator of NOx and VOC Controls on Surface Ozone Formation

NASA Technical Reports Server (NTRS)

Duncan, Bryan N.; Yoshida, Yasuko; Olson, Jennifer R.; Sillman, Sanford; Martin, Randall V.; Lamsal, Lok; Hu, Yongtao; Pickering, Kenneth E.; Retscher, Christian; Allen, Dale J.;

Herschel Extreme Lensing Line Observations: [CII] Variations in Galaxies at Redshifts z=1-3*

NASA Technical Reports Server (NTRS)

Malhotra, Sangeeta; Rhoads, James E.; Finkelstein, K.; Yang, Huan; Carilli, Chris; Combes, Francoise; Dassas, Karine; Finkelstein, Steven; Frye, Brenda; Gerin, Maryvonne;

Herschel Extreme Lensing Line Observations: [CII] Variations in Galaxies at Redshifts z=1-3

NASA Astrophysics Data System (ADS)

Malhotra, Sangeeta; Rhoads, James E.; Finkelstein, K.; Yang, Huan; Carilli, Chris; Combes, Françoise; Dassas, Karine; Finkelstein, Steven; Frye, Brenda; Gerin, Maryvonne; Guillard, Pierre; Nesvadba, Nicole; Rigby, Jane; Shin, Min-Su; Spaans, Marco; Strauss, Michael A.; Papovich, Casey

2017-01-01

We observed the [C II] line in 15 lensed galaxies at redshifts 1 < z < 3 using HIFI on the Herschel Space Observatory and detected 14/15 galaxies at 3σ or better. High magnifications enable even modestly luminous galaxies to be detected in [C II] with Herschel. The [C II] luminosity in this sample ranges from 8 × 107 L⊙ to 3.7 × 109 L⊙ (after correcting for magnification), confirming that [C II] is a strong tracer of the ISM at high redshifts. The ratio of the [C II] line to the total far-infrared (FIR) luminosity serves as a measure of the ratio of gas to dust cooling and thus the efficiency of the grain photoelectric heating process. It varies between 3.3% and 0.09%. We compare the [C II]/FIR ratio to that of galaxies at z = 0 and at high redshifts and find that they follow similar trends. The [C II]/FIR ratio is lower for galaxies with higher dust temperatures. This is best explained if increased UV intensity leads to higher FIR luminosity and dust temperatures, but gas heating does not rise due to lower photoelectric heating efficiency. The [C II]/FIR ratio shows weaker correlation with FIR luminosity. At low redshifts highly luminous galaxies tend to have warm dust, so the effects of dust temperature and luminosity are degenerate. Luminous galaxies at high redshifts show a range of dust temperatures, showing that [C II]/FIR correlates most strongly with dust temperature. The [C II] to mid-IR ratio for the HELLO sample is similar to the values seen for low-redshift galaxies, indicating that small grains and PAHs dominate the heating in the neutral ISM, although some of the high [CII]/FIR ratios may be due to turbulent heating. Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA.

HERSCHEL EXTREME LENSING LINE OBSERVATIONS: [C ii] VARIATIONS IN GALAXIES AT REDSHIFTS z = 1–3

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

Malhotra, Sangeeta; Rhoads, James E.; Yang, Huan

We observed the [C ii] line in 15 lensed galaxies at redshifts 1 < z < 3 using HIFI on the Herschel Space Observatory and detected 14/15 galaxies at 3 σ or better. High magnifications enable even modestly luminous galaxies to be detected in [C ii] with Herschel . The [C ii] luminosity in this sample ranges from 8 × 10{sup 7} L {sub ⊙} to 3.7 × 10{sup 9} L {sub ⊙} (after correcting for magnification), confirming that [C ii] is a strong tracer of the ISM at high redshifts. The ratio of the [C ii] line to themore » total far-infrared (FIR) luminosity serves as a measure of the ratio of gas to dust cooling and thus the efficiency of the grain photoelectric heating process. It varies between 3.3% and 0.09%. We compare the [C ii]/FIR ratio to that of galaxies at z = 0 and at high redshifts and find that they follow similar trends. The [C ii]/FIR ratio is lower for galaxies with higher dust temperatures. This is best explained if increased UV intensity leads to higher FIR luminosity and dust temperatures, but gas heating does not rise due to lower photoelectric heating efficiency. The [C ii]/FIR ratio shows weaker correlation with FIR luminosity. At low redshifts highly luminous galaxies tend to have warm dust, so the effects of dust temperature and luminosity are degenerate. Luminous galaxies at high redshifts show a range of dust temperatures, showing that [C ii]/FIR correlates most strongly with dust temperature. The [C ii] to mid-IR ratio for the HELLO sample is similar to the values seen for low-redshift galaxies, indicating that small grains and PAHs dominate the heating in the neutral ISM, although some of the high [CII]/FIR ratios may be due to turbulent heating.« less

Electron temperature maps of the low solar corona: ISCORE results from the total solar eclipse of 1 August 2008 in China

NASA Astrophysics Data System (ADS)

Reginald, Nelson L.; Davila, Joseph M.; St. Cyr, Orville C.; Rabin, Douglas M.

2017-06-01

We conducted an experiment in conjunction with the total solar eclipse of 1 August 2008 in China to determine the thermal electron temperature in the low solar corona close to the solar limb. The instrument, Imaging Spectrograph of Coronal Electrons (ISCORE), consisted of an 8 inch f/10 Schmidt Cassegrain telescope with a thermoelectrically cooled CCD camera at the focal plane. Results are electron temperatures of 1 MK at 1.08 R⊙ and 1.13 R⊙ from the Sun center in the polar and equatorial regions, respectively. This experiment confirms the results of an earlier experiment conducted in conjunction with the total eclipse of 29 March 2006 in Libya, and results are that at a given coronal height the electron temperature in the polar region is larger than at the equatorial region. In this paper we show the importance of using the correct photospheric spectrum pertinent to the solar activity phase at the time of the experiment, which is a required parameter for modeling the underlying theoretical concept for temperature interpretation of the measured intensity ratios using color filters.

Blade row dynamic digital compressor program. Volume 1: J85 clean inlet flow and parallel compressor models

NASA Technical Reports Server (NTRS)

Tesch, W. A.; Steenken, W. G.

1976-01-01

The results are presented of a one-dimensional dynamic digital blade row compressor model study of a J85-13 engine operating with uniform and with circumferentially distorted inlet flow. Details of the geometry and the derived blade row characteristics used to simulate the clean inlet performance are given. A stability criterion based upon the self developing unsteady internal flows near surge provided an accurate determination of the clean inlet surge line. The basic model was modified to include an arbitrary extent multi-sector parallel compressor configuration for investigating 180 deg 1/rev total pressure, total temperature, and combined total pressure and total temperature distortions. The combined distortions included opposed, coincident, and 90 deg overlapped patterns. The predicted losses in surge pressure ratio matched the measured data trends at all speeds and gave accurate predictions at high corrected speeds where the slope of the speed lines approached the vertical.

The Ratio of Ortho- to Para-H2 in Photodissociation Regions

NASA Technical Reports Server (NTRS)

Sternberg, Amiel; Neufeld, David A.

1999-01-01

We discuss the ratio of ortho- to para-H2 in photodissociation regions (PDRs). We draw attention to an apparent confusion in the literature between the ortho-to-para ratio of molecules in FUV-pumped vibrationally excited states and the total H2 ortho-to-para abundance ratio. These ratios are not the same because the process of FUV pumping of fluorescent H2 emission in PDRs occurs via optically thick absorption lines. Thus gas with an equilibrium ratio of ortho- to para-H2 equal to 3 will yield FUV-pumped vibrationally excited ortho-to-para ratios smaller than 3, because the ortho-H2 pumping rates are preferentially reduced by optical depth effects. Indeed, if the ortho and para pumping lines are on the "square root" part of the curve of growth, then the expected ratio of ortho and para vibrational line strengths is 3(sup 1/2) approximately 1.7, close to the typically observed value. Thus, contrary to what has sometimes been stated in the literature, most previous measurements of the ratio of ortho- to para-H2 in vibrationally excited states are entirely consistent with a total ortho-to-para ratio of 3, the equilibrium value for temperatures greater than 200 K. We present an analysis and several detailed models that illustrate the relationship between the total ratios of ortho- to para-H2 and the vibrationally excited ortho-to-para ratios in PDRs. Recent Infrared Space Observatory measurements of pure rotational and vibrational H2 emissions from the PDR in the star-forming region S140 provide strong observational support for our conclusions.

Maximum production of fermentable sugars from barley straw using optimized soaking in aqueous ammonia (SAA) pretreatment

USDA-ARS?s Scientific Manuscript database

Soaking in aqueous ammonia (SAA) pretreatment was investigated to improve enzymatic digestibility and consequently to increase total fermentable sugar production from barley straw. Various effects of pretreatment process parameters, such as reaction temperature, reaction time, solid:liquid ratio, an...

Experimental investigation of drying characteristics of cornelian cherry fruits ( Cornus mas L.)

NASA Astrophysics Data System (ADS)

Ozgen, Filiz

2015-03-01

Major target of present paper is to investigate the drying kinetics of cornelian cherry fruits ( Cornus mas L.) in a convective dryer, by varying the temperature and the velocity of drying air. Freshly harvested fruits are dried at drying air temperature of 35, 45 and 55 °C. The considered drying air velocities are V air = 1 and 1.5 m/s for each temperature. The required drying time is determined by taking into consideration the moisture ratio measurements. When the moisture ratio reaches up to 10 % at the selected drying air temperature, then the time is determined ( t = 40-67 h). The moisture ratio, fruit temperature and energy requirement are presented as the functions of drying time. The lowest drying time (40 h) is obtained when the air temperature is 55 °C and air velocity is 1.5 m/s. The highest drying time (67 h) is found under the conditions of 35 °C temperature and 1 m/s velocity. Both the drying air temperature and the air velocity significantly affect the required energy for drying system. The minimum amount of required energy is found as 51.12 kWh, at 55 °C and 1 m/s, whilst the maximum energy requirement is 106.7 kWh, at 35 °C and 1.5 m/s. It is also found that, air temperature significantly influences the total drying time. Moreover, the energy consumption is decreasing with increasing air temperature. The effects of three parameters (air temperature, air velocity and drying time) on drying characteristics have also been analysed by means of analysis of variance method to show the effecting levels. The experimental results have a good agreement with the predicted ones.

Physical Conditions in the Solar Corona Derived from the Total Solar Eclipse Observations obtained on 2017 August 21 Using a Polarization Camera

NASA Astrophysics Data System (ADS)

Gopalswamy, N.; Yashiro, Seiji; Reginald, Nelson; Thakur, Neeharika; Thompson, Barbara J.; Gong, Qian

2018-01-01

We present preliminary results obtained by observing the solar corona during the 2017 August 21 total solar eclipse using a polarization camera mounted on an eight-inch Schmidt-Cassegrain telescope. The observations were made from Madras Oregon during 17:19 to 17:21 UT. Total and polarized brightness images were obtained at four wavelengths (385, 398.5, 410, and 423 nm). The polarization camera had a polarization mask mounted on a 2048x2048 pixel CCD with a pixel size of 7.4 microns. The resulting images had a size of 975x975 pixels because four neighboring pixels were summed to yield the polarization and total brightness images. The ratio of 410 and 385 nm images is a measure of the coronal temperature, while that at 423 and 398.5 nm images is a measure of the coronal flow speed. We compared the temperature map from the eclipse observations with that obtained from the Solar Dynamics Observatory’s Atmospheric Imaging Assembly images at six EUV wavelengths, yielding consistent temperature information of the corona.

Parametric test results of a swirl-can combustor

NASA Technical Reports Server (NTRS)

Niedzwiecki, R. W.; Jones, R. E.

1973-01-01

Pollutant levels of oxides of nitrogen, unburned hydrocarbons, and carbon monoxide were measured for three models of an experimental, annular swirl can combustor. The combustor was 1.067 meters in outer diameter, incorporated 120 modules, and was specifically designed for elevated exit temperature performance. Test conditions included combustor inlet temperatures of 589, 756 and 839 K, inlet pressures of 3 to 6.4 atmospheres, reference velocities of 21 to 38 meters per second and combustor equivalence ratios, based on total combustor flows of 0.206 to 1.028. Maximum oxides of nitrogen emission index values occurred at an equivalence ratio of 0.7 with lower values measured for both higher and lower equivalence ratios. Oxides of nitrogen concentrations, to the 0.7 level with 756 K inlet air, were correlated for the three models by a combined parameter consisting of measured flow and geometric parameters. Effects of the individual parameters comprising the correlation are also presented.

Optimization of the Synthesis of Structured Phosphatidylcholine with Medium Chain Fatty Acid.

PubMed

Ochoa-Flores, Angélica A; Hernández-Becerra, Josafat A; Cavazos-Garduño, Adriana; Vernon-Carter, Eduardo J; García, Hugo S

2017-11-01

Structured phosphatidylcholine was successfully produced by acidolysis between phosphatidylcholine and free medium chain fatty acid, using phospholipase A 1 immobilized on Duolite A568. Response surface methodology was applied to optimize the reaction system using three process parameters: molar ratio of substrates (phosphatidylcholine to free medium chain fatty acid), enzyme loading, and reaction temperature. All parameters evaluated showed linear and quadratic significant effects on the production of modified phosphatidylcholine; molar ratio of substrates contributed positively, but temperature influenced negatively. Increased enzyme loading also led to increased production of modified phosphatidylcholine but only during the first 9 hours of the acidolysis reaction. Optimal conditions obtained from the model were a ratio of phosphatidylcholine to free medium chain fatty acid of 1:15, an enzyme loading of 12%, and a temperature of 45°C. Under these conditions a production of modified phosphatidylcholine of 52.98 % were obtained after 24 h of reaction. The prediction was confirmed from the verification experiments; the production of modified phosphatidylcholine was 53.02%, the total yield of phosphatidylcholine 64.28% and the molar incorporation of medium chain fatty acid was 42.31%. The acidolysis reaction was scaled-up in a batch reactor with a similar production of modified phosphatidylcholine, total yield of phosphatidylcholine and molar incorporation of medium chain fatty acid. Purification by column chromatography of the structured phosphatidylcholine yielded 62.53% of phosphatidylcholine enriched with 42.52% of medium chain fatty acid.

Determination of the spatial and temporal variability of phytoplankton community structure in Daya Bay via HPLC-CHEMTAX pigment analysis

NASA Astrophysics Data System (ADS)

Wang, Longhua; Ou, Linjian; Huang, Kaixuan; Chai, Chao; Wang, Zhaohui; Wang, Xiaomin; Jiang, Tao

2017-09-01

The spatial and temporal variability of the phytoplankton community structure in Daya Bay, South China Sea, were identified by using HPLC-CHEMTAX analytical techniques. The highest chlorophyll a (Chl a) concentrations were observed during summer (with an average value of 0.84 μg/L) and lowest ones during winter (with an average value of 0.33 μg/L). CHEMTAX processing revealed the seasonal succession of phytoplankton species in Daya Bay. During winter, diatoms were the dominant phytoplankton species and contributed 41.5% to total Chl a. Based on Chl a concentration, the average ratio of dinoflagellates to total phytoplankton biomass substantially increased with increasing temperature and nitrogen to phosphorus (N/P) ratio, reaching 52.2% in spring. Nutrient limitation shifted from phosphorus to nitrogen during summer. Moreover, this period was associated with the predominance of diatoms, which accounted for 71.1% of Chl a. Prasinophytes and cryptophytes were the other two dominant groups and particularly dominated during winter. Cyanobacteria became an important group during summer and autumn. Canonical correspondence analysis suggested that chrysophytes, dinoflagellates, and cryptophytes were strongly associated with high nitrate concentration, ammonium, dissolved inorganic nitrogen (DIN), and N/P ratio, and were negatively associated with temperature and phosphate. Diatoms and cyanobacteria were strongly associated with temperature, phosphate, and salinity, and are negatively influenced by nitrate, ammonium, DIN, and N/P ratio. Microscopic observations and pigment HPLC information were in good agreement for diatoms and dinoflagellates in the bay. This study demonstrated the usefulness of pigment analysis in investigating the distribution of phytoplankton groups in a complex physical environment, such as Daya Bay.

Dependence of N-polar GaN rod morphology on growth parameters during selective area growth by MOVPE

NASA Astrophysics Data System (ADS)

Li, Shunfeng; Wang, Xue; Mohajerani, Matin Sadat; Fündling, Sönke; Erenburg, Milena; Wei, Jiandong; Wehmann, Hergo-Heinrich; Waag, Andreas; Mandl, Martin; Bergbauer, Werner; Strassburg, Martin

2013-02-01

Selective area growth of GaN rods by metalorganic vapor phase epitaxy has attracted great interest due to its novel applications in optoelectronic and photonics. In this work, we will present the dependence of GaN rod morphology on various growth parameters i.e. growth temperature, H2/N2 carrier gas concentration, V/III ratio, total carrier gas flow and reactor pressure. It is found that higher growth temperature helps to increase the aspect ratio of the rods, but reduces the height homogeneity. Furthermore, H2/N2 carrier gas concentration is found to be a critical factor to obtain vertical rod growth. Pure nitrogen carrier gas leads to irregular growth of GaN structure, while an increase of hydrogen carrier gas results in vertical GaN rod growth. Higher hydrogen carrier gas concentration also reduces the diameter and enhances the aspect of the GaN rods. Besides, increase of V/III ratio causes reduction of the aspect ratio of N-polar GaN rods, which could be explained by the relatively lower growth rate on (000-1) N-polar top surface when supplying more ammonia. In addition, an increase of the total carrier gas flow leads to a decrease in the diameter and the average volume of GaN rods. These phenomena are tentatively explained by the change of partial pressure of the source materials and boundary layer thickness in the reactor. Finally, it is shown that the average volume of the N-polar GaN rods keeps a similar value for a reactor pressure PR of 66 and 125 mbar, while an incomplete filling of the pattern opening is observed with PR of 250 mbar. Room temperature photoluminescence spectrum of the rods is also briefly discussed.

Designing Ground Antennas for Maximum G/T: Cassegrain or Gregorian?

NASA Technical Reports Server (NTRS)

Imbriale, William A.

2005-01-01

For optimum performance, a ground antenna system must maximize the ratio of received signal to the receiving system noise power, defined as the ratio of antenna gain to system-noise temperature (G/T). The total system noise temperature is the linear combination of the receiver noise temperature (including the feed system losses) and the antenna noise contribution. Hence, for very low noise cryogenic receiver systems, antenna noise-temperature properties are very significant contributors to G/T.It is well known that, for dual reflector systems designed for maximum gain, the gain performance of the antenna system is the same for both Cassegrain and Gregorian configurations. For a12-meter antenna designed to be part of the large array based Deep Space Network, a Cassegrain configuration designed for maximum G/T at X-band was 0.7 dB higher than the equivalent Gregorian configuration. This study demonstrates that, for maximum GIT, the dual shaped Cassegrain design is always better than the Gregorian.

The conversion of biomass to light olefins on Fe-modified ZSM-5 catalyst: Effect of pyrolysis parameters.

PubMed

Zhang, Shihong; Yang, Mingfa; Shao, Jingai; Yang, Haiping; Zeng, Kuo; Chen, Yingquan; Luo, Jun; Agblevor, Foster A; Chen, Hanping

2018-07-01

Light olefins are the key building blocks for the petrochemical industry. In this study, the effects of in-situ and ex-situ process, temperature, Fe loading, catalyst to feed ratio and gas flow rate on the olefins carbon yield and selectivity were explored. The results showed that Fe-modified ZSM-5 catalyst increased the olefins yield significantly, and the ex-situ process was much better than in-situ. With the increasing of temperature, Fe-loading amount, catalyst to feed ratio, and gas flow rate, the carbon yields of light olefins were firstly increased and further decreased. The maximum carbon yield of light olefins (6.98% C-mol) was obtained at the pyrolysis temperature of 600°C, catalyst to feed ratio of 2, gas flow rate of 100ml/min, and 3wt% Fe/ZSM-5 for cellulose. The selectivity of C 2 H 4 was more than 60% for all feedstock, and the total light olefins followed the decreasing order of cellulose, corn stalk, hemicelluloses and lignin. Copyright © 2018 Elsevier B.V. All rights reserved.

Influence of the overfire air ratio on the NO(x) emission and combustion characteristics of a down-fired 300-MW(e) utility boiler.

PubMed

Ren, Feng; Li, Zhengqi; Chen, Zhichao; Fan, Subo; Liu, Guangkui

2010-08-15

Down-fired boilers used to burn low-volatile coals have high NO(x) emissions. To find a way of solving this problem, an overfire air (OFA) system was introduced on a 300 MW(e) down-fired boiler. Full-scale experiments were performed on this retrofitted boiler to explore the influence of the OFA ratio (the mass flux ratio of OFA to the total combustion air) on the combustion and NO(x) emission characteristics in the furnace. Measurements were taken of gas temperature distributions along the primary air and coal mixture flows, average gas temperatures along the furnace height, concentrations of gases such as O(2), CO, and NO(x) in the near-wall region and carbon content in the fly ash. Data were compared for five different OFA ratios. The results show that as the OFA ratio increases from 12% to 35%, the NO(x) emission decreases from 1308 to 966 mg/Nm(3) (at 6% O(2) dry) and the carbon content in the fly ash increases from 6.53% to 15.86%. Considering both the environmental and economic effect, 25% was chosen as the optimized OFA ratio.

Chemical and antioxidant properties of snake tomato (Trichosanthes cucumerina) juice and Pineapple (Ananas comosus) juice blends and their changes during storage.

PubMed

Bamidele, Oluwaseun P; Fasogbon, Mofoluwaso B

2017-04-01

Juice blends made from the mixture of snake tomato (Trichosanthes cucumerina) and Pineapple (Ananas comosus) fruits were analyzed for pH, antioxidant properties, total titratable acidity, vitamin C, lycopene and total phenolic contents after different blend ratios were made. The addition of snake tomato juice increased the vitamin C, total carotene, lycopene and antioxidant properties of the juice blends. The radical scavenging properties of juice blends containing a higher ratio of snake tomato were higher and samples stored at room temperature (29°C) showed an increase in antioxidant properties compared to samples stored at 4°C. In conclusion, snake tomato juice up to 50% may be added to Pineapple juice to make a healthy juice blend. Copyright © 2016 Elsevier Ltd. All rights reserved.

Pollutant formation in fuel lean recirculating flows. Ph.D. Thesis. Final Report; [in an Opposed Reacting Jet Combustor

NASA Technical Reports Server (NTRS)

Schefer, R. W.; Sawyer, R. F.

1976-01-01

An opposed reacting jet combustor (ORJ) was tested at a pressure of 1 atmosphere. A premixed propane/air stream was stabilized by a counterflowing jet of the same reactants. The resulting intensely mixed zone of partially reacted combustion products produced stable combustion at equivalence ratios as low as 0.45. Measurements are presented for main stream velocities of 7.74 and 13.6 m/sec with an opposed jet velocity of 96 m/sec, inlet air temperatures from 300 to 600 K, and equivalence ratios from 0.45 to 0.625. Fuel lean premixed combustion was an effective method of achieving low NOx emissions and high combustion efficiencies simultaneously. Under conditions promoting lower flame temperature, NO2 constituted up to 100 percent of the total NOx. At higher temperatures this percentage decreased to a minimum of 50 percent.

Atomic concentration effect on thermal properties during solidification of Pt-Rh alloy: A molecular dynamics simulation

NASA Astrophysics Data System (ADS)

Yildiz, A. K.; Celik, F. A.

2017-04-01

The solidification process of Platinum-Rhodium alloy from liquid phase to solid state is investigated at the nano-scale by using Molecular Dynamics Simulation (MDS) for different atomic concentration ratios of Pt. The critical nucleus radius, the bond order parameter, interfacial free energies and total energy based on nucleation theory of the alloy are examined with respect to the temperature changes. The heat of fusion from high temperatures to low temperatures during solidification of the alloy system is determined from molecular dynamics simulation. The structural development is determined from the radial distribution function. It is observed from the results that the melting point of the alloy system decreases with increasing concentration of Pt and that variation of Pt ratio in the alloy shows a remarkable effect on solidification to understand the cooling process of thermal effects.

The noise and flow characteristics of inverted-profile coannular jets

NASA Technical Reports Server (NTRS)

Tanna, H. K.; Tester, B. J.; Lau, J. C.

1979-01-01

A basic understanding of the noise reduction mechanisms in shock-free inverted-velocity-profile coannular jets was studied. Acoustic measurements are first conducted in an anechoic facility to isolate the effects of inverted velocity and inverted temperature for coannular jets having constant total thrust, mass flow rate and exit area. To obtain physical explanations of the measured noise changes, several types of experiments are conducted. These include (1) source location experiments using the polar correlation technique, (2) mean flow surveys using a combination pressure/temperature probe, and (3) detailed mean flow and turbulence measurements using a two-point four-channel laser velocimeter. The results from these experiments are presented and discussed in detail. Finally, the measured variations of coannular jet mixing noise with fan-to-primary velocity ratio and static temperature ratio are interpreted by utilizing the results from the various experimental phases in conjunction with the existing Lockheed single jet noise prediction model.

Effect of pyrolysis temperature on the chemical oxidation stability of bamboo biochar.

PubMed

Chen, Dengyu; Yu, Xinzhi; Song, Chao; Pang, Xiaoli; Huang, Jing; Li, Yanjun

2016-10-01

Biochar produced by biomass pyrolysis has the advantage of carbon sequestration. However, some of the carbon atoms in biochar are not very stable. In this study, the effect of pyrolysis temperature on the chemical oxidation stability of bamboo biochar was investigated using the atomic ratios of H/C and O/C, Fourier transform infrared spectroscopy, and potassium dichromate (K2Cr2O7) oxidation spectrophotometric method. The results show that the carbon yield and ratios of H/C and O/C decreased from 71.72%, 0.71, and 0.32 to 38.48%, 0.22, and 0.06, respectively, as the temperature was increased from 300°C to 700°C. Moreover, the main oxygen-containing functional groups gradually decreased, while the degree of aromatization increased accordingly. The biochar showed a better stability at a higher pyrolysis temperature. The proportion of carbon loss, i.e., the amount of oxidized carbon with respect to the total carbon of the biochar, decreased from 16.52% to 6.69% with increasing temperature. Copyright © 2016 Elsevier Ltd. All rights reserved.

EERC pilot-scale CFBC evaluation facility Project CFB test results. Topical report, Task 7.30

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

Mann, M.D.; Hajicek, D.R.; Henderson, A.K.

Project CFB was initiated at the University of North Dakota Energy and Environmental Research Center (EERC) in May 1988. Specific goals of the project were to (1) construct a circulating fluidized-bed combustor (CFBC) facility representative of the major boiler vendors` designs with the capability of producing scalable data, (2) develop a database for use in making future evaluations of CFBC technology, and (3) provide a facility for evaluating fuels, free of vendor bias for use in the - energy industry. Five coals were test-burned in the 1-MWth unit: North Dakota and Asian lignites, a Wyoming subbituminous, and Colorado and Pennsylvaniamore » bituminous coats. A total of 54 steady-state test periods were conducted, with the key test parameters being the average combustor temperature, excess air, superficial gas velocity, calcium-to-sulfur molar ratio, and the primary air-to-secondary air split. The capture for a coal fired in a CFBC is primarily dependent upon the total alkali-to-sulfur ratio. The required alkali-to ratio for 90% sulfur retention ranged from 1.4 to 4.9, depending upon coal type. While an alkali-to-ratio of 4.9 was required to meet 90% sulfur retention for the Salt Creek coal versus 1.4 for the Asian lignite, the total amount of sorbent addition required is much less for the Salt Creek coal, 4.2 pound sorbent per million Btu coal input, versus 62 pound/million Btu for the Asian lignite. The bituminous coals tested show optimal capture at combustor temperatures of approximately 1550{degree}F, with low-rank coals having optimal sulfur capture approximately 100{degree}F lower.« less

EERC pilot-scale CFBC evaluation facility Project CFB test results

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

Mann, M.D.; Hajicek, D.R.; Henderson, A.K.

Project CFB was initiated at the University of North Dakota Energy and Environmental Research Center (EERC) in May 1988. Specific goals of the project were to (1) construct a circulating fluidized-bed combustor (CFBC) facility representative of the major boiler vendors' designs with the capability of producing scalable data, (2) develop a database for use in making future evaluations of CFBC technology, and (3) provide a facility for evaluating fuels, free of vendor bias for use in the - energy industry. Five coals were test-burned in the 1-MWth unit: North Dakota and Asian lignites, a Wyoming subbituminous, and Colorado and Pennsylvaniamore » bituminous coats. A total of 54 steady-state test periods were conducted, with the key test parameters being the average combustor temperature, excess air, superficial gas velocity, calcium-to-sulfur molar ratio, and the primary air-to-secondary air split. The capture for a coal fired in a CFBC is primarily dependent upon the total alkali-to-sulfur ratio. The required alkali-to ratio for 90% sulfur retention ranged from 1.4 to 4.9, depending upon coal type. While an alkali-to-ratio of 4.9 was required to meet 90% sulfur retention for the Salt Creek coal versus 1.4 for the Asian lignite, the total amount of sorbent addition required is much less for the Salt Creek coal, 4.2 pound sorbent per million Btu coal input, versus 62 pound/million Btu for the Asian lignite. The bituminous coals tested show optimal capture at combustor temperatures of approximately 1550[degree]F, with low-rank coals having optimal sulfur capture approximately 100[degree]F lower.« less

Production of reducing sugar from Enteromorpha intestinalis by hydrothermal and enzymatic hydrolysis.

PubMed

Kim, Dong-Hyun; Lee, Sang-Bum; Jeong, Gwi-Taek

2014-06-01

In this work, to evaluate the efficacy of marine macro-algae Enteromorpha intestinalis as a potential bioenergy resource, the effects of reaction conditions (solid-to-liquid ratio, reaction temperature, and reaction time) on sugars produced by a combined process of hydrothermal and enzymatic hydrolysis were investigated. As a result of the hydrothermal hydrolysis, a 7.3g/L (8% yield) total reducing sugar was obtained under conditions including solid-to-liquid ratio of 1:10, reaction temperature of 170°C, and reaction time of 60min. By subsequent (post-hydrothermal) enzymatic hydrolysis of samples treated at 170°C for 30min, a 20.1g/L (22% yield) was achieved. Copyright © 2014 Elsevier Ltd. All rights reserved.

Meteorological and constituent data for January and February 1981

NASA Technical Reports Server (NTRS)

1981-01-01

Balloon data consisting of a plot showing the mixing ratio of ozone partial pressure in micromillibors and temperature in degrees centigrade versus pressure altitude in millibars is presented. An accompanying tabulation of meteorological and constituent data is also presented. The total overburden was aquired by Dobson Spectrophotometer 72.

Simulated Altitude Performance of Combustor of Westinghouse 19XB-1 Jet-Propulsion Engine

NASA Technical Reports Server (NTRS)

Childs, J. Howard; McCafferty, Richard J.

1948-01-01

A 19XB-1 combustor was operated under conditions simulating zero-ram operation of the 19XB-1 turbojet engine at various altitudes and engine speeds. The combustion efficiencies and the altitude operational limits were determined; data were also obtained on the character of the combustion, the pressure drop through the combustor, and the combustor-outlet temperature and velocity profiles. At altitudes about 10,000 feet below the operational limits, the flames were yellow and steady and the temperature rise through the combustor increased with fuel-air ratio throughout the range of fuel-air ratios investigated. At altitudes near the operational limits, the flames were blue and flickering and the combustor was sluggish in its response to changes in fuel flow. At these high altitudes, the temperature rise through the combustor increased very slowly as the fuel flow was increased and attained a maximum at a fuel-air ratio much leaner than the over-all stoichiometric; further increases in fuel flow resulted in decreased values of combustor temperature rise and increased resonance until a rich-limit blow-out occurred. The approximate operational ceiling of the engine as determined by the combustor, using AN-F-28, Amendment-3, fuel, was 30,400 feet at a simulated engine speed of 7500 rpm and increased as the engine speed was increased. At an engine speed of 16,000 rpm, the operational ceiling was approximately 48,000 feet. Throughout the range of simulated altitudes and engine speeds investigated, the combustion efficiency increased with increasing engine speed and with decreasing altitude. The combustion efficiency varied from over 99 percent at operating conditions simulating high engine speed and low altitude operation to less than 50 percent at conditions simulating operation at altitudes near the operational limits. The isothermal total pressure drop through the combustor was 1.82 times as great as the inlet dynamic pressure. As expected from theoretical considerations, a straight-line correlation was obtained when the ratio of the combustor total pressure drop to the combustor-inlet dynamic pressure was plotted as a function of the ratio of the combustor-inlet air density to the combustor-outlet gas density. The combustor-outlet temperature profiles were, in general, more uniform for runs in which the temperature rise was low and the combustion efficiency was high. Inspection of the combustor basket after 36 hours of operation showed very little deterioration and no appreciable carbon deposits.

Altitude engine test of a turbofan exhaust gas mixer to conserve fuel

NASA Technical Reports Server (NTRS)

Cullom, R. R.; Johnsen, R. L.

1977-01-01

A comparison of the specific fuel consumption was made with and without an internal mixer installed in a low bypass ratio, confluent flow turbofan engine. Tests were conducted at several Mach numbers and altitudes for core to fan stream total temperature ratios of 2.0 and 2.5 and mixing lengths of L/D = 0.95 and 1.74. For these test conditions, the specific fuel consumption improvement varied from 2.5 to 4.0 percent.

Total temperature probes for high-temperature hypersonic boundary-layer measurements

NASA Technical Reports Server (NTRS)

Albertson, Cindy W.; Bauserman, Willard A., Jr.

1993-01-01

The design and test results of two types of total temperature probes that were used for hypersonic boundary-layer measurements are presented. The intent of each design was to minimize the total error and to maintain minimal size for measurements in boundary layers 1.0 in. thick and less. A single platinum-20-percent-rhodium shield was used in both designs to minimize radiation heat transfer losses during exposure to the high-temperature test stream. The shield of the smaller design was flattened at the flow entrance to an interior height of 0.02 in., compared with 0.03 in. for the larger design. The resulting vent-to-inlet area ratios were 60 and 50 percent. A stainless steel structural support sleeve that was used in the larger design was excluded from the smaller design, which resulted in an outer diameter of 0.059 in., to allow closer placement of the probes to each other and to the wall. These small design changes to improve resolution did not affect probe performance. Tests were conducted at boundary-layer-edge Mach numbers of 5.0 and 6.2. The nominal free-stream total temperatures were 2600 degrees and 3200 degrees R. The probes demonstrated extremely good reliability. The best performance in terms of recovery factor occurred when the wire-based Nusselt number was at least 0.04. Recommendations for future probe designs are included.

High-Spatial-Resolution OH PLIF Visualization in a Cavity-Stabilized Ethylene-Air Turbulent Flame

NASA Technical Reports Server (NTRS)

Geipel, Clayton M.; Rockwell, Robert D.; Chelliah, Harsha K.; Cutler, Andrew D.; Spelker, Christopher A.; Hashem, Zeid; Danehy, Paul M.

2017-01-01

High-spatial-resolution OH planar laser-induced fluorescence was measured for a premixed ethylene-air turbulent flame in an electrically-heated Mach 2 continuous-flow facility (University of Virginia Supersonic Combustion Facility, Configuration E.) The facility comprised a Mach 2 nozzle, an isolator with flush-wall fuel injectors, a combustor with optical access, and an extender. The flame was anchored at a cavity flameholder with a backward-facing step of height 9 mm. The temperature-insensitive Q1(8) transition of OH was excited using laser light of wavelength 283.55 nm. A spatial filter was used to create a laser sheet approximately 25 microns thick based on full-width at half maximum (FWHM). Extension tubes increased the magnification of an intensified camera system, achieving in-plane resolution of 40 microns based on a 50% modulation transfer function (MTF). The facility was tested with total temperature 1200 K, total pressure 300 kPa, local fuel/air equivalence ratios of approximately 0.4, and local Mach number of approximately 0.73 in the combustor. A test case with reduced total temperature and another with reduced equivalence ratio were also tested. PLIF images were acquired along a streamwise plane bisecting the cavity flameholder, from the backward facing step to 120 mm downstream of the step. The smallest observed features in the flow had width of approximately 110 microns. Flame surface density was calculated for OH PLIF images.

Optimization of ultrasonic-assisted extraction of total saponins from Eclipta prostrasta L. using response surface methodology.

PubMed

Hu, Ting; Guo, Yan-Yun; Zhou, Qin-Fan; Zhong, Xian-Ke; Zhu, Liang; Piao, Jin-Hua; Chen, Jian; Jiang, Jian-Guo

2012-09-01

Eclipta prostrasta L. is a traditional Chinese medicine herb, which is rich in saponins and has strong antiviral and antitumor activities. An ultrasonic-assisted extraction (UAE) technique was developed for the fast extraction of saponins from E. prostrasta. The content of total saponins in E. prostrasta was determined using UV/vis spectrophotometric methods. Several influential parameters like ethanol concentration, extraction time, temperature, and liquid/solid ratio were investigated for the optimization of the extraction using single factor and Box-Behnken experimental designs. Extraction conditions were optimized for maximum yield of total saponins in E. prostrasta using response surface methodology (RSM) with 4 independent variables at 3 levels of each variable. Results showed that the optimization conditions for saponins extraction were: ethanol concentration 70%, extraction time 3 h, temperature 70 °C, and liquid/solid ratio 14:1. Corresponding saponins content was 2.096%. The mathematical model developed was found to fit well with the experimental data. Practical Application: Although there are wider applications of Eclipta prostrasta L. as a functional food or traditional medicine due to its various bioactivities, these properties are limited by its crude extracts. Total saponins are the main active ingredient of E. prostrasta. This research has optimized the extraction conditions of total saponins from E. prostrasta, which will provide useful reference information for further studies, and offer related industries with helpful guidance in practice. © 2012 Institute of Food Technologists®

Chemical and Sr isotopic characterization of North America uranium ores: Nuclear forensic applications

DOE PAGES

Balboni, Enrica; Jones, Nina; Spano, Tyler; ...

2016-08-31

This study reports major, minor, and trace element data and Sr isotope ratios for 11 uranium ore (uraninite, UO 2+x) samples and one processed uranium ore concentrate (UOC) from various U.S. deposits. The uraninite investigated represent ores formed via different modes of mineralization (e.g., high- and low-temperature) and within various geological contexts, which include magmatic pegmatites, metamorphic rocks, sandstone-hosted, and roll front deposits. In situ trace element data obtained by laser ablation-ICP-MS and bulk sample Sr isotopic ratios for uraninite samples investigated here indicate distinct signatures that are highly dependent on the mode of mineralization and host rock geology. Relativemore » to their high-temperature counterparts, low-temperature uranium ores record high U/Th ratios (>1000), low total rare earth element (REE) abundances (<1 wt%), high contents (>300 ppm) of first row transition metals (Sc, Ti, V, Cr, Mn, Co, Ni), and radiogenic 87Sr/ 86Sr ratios (>0.7200). Comparison of chondrite normalized REE patterns between uraninite and corresponding processed UOC from the same locality indicates identical patterns at different absolute concentrations. Lastly, this result ultimately confirms the importance of establishing geochemical signatures of raw, uranium ore materials for attribution purposes in the forensic analysis of intercepted nuclear materials.« less

Chemical and Sr isotopic characterization of North America uranium ores: Nuclear forensic applications

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

Balboni, Enrica; Jones, Nina; Spano, Tyler

This study reports major, minor, and trace element data and Sr isotope ratios for 11 uranium ore (uraninite, UO 2+x) samples and one processed uranium ore concentrate (UOC) from various U.S. deposits. The uraninite investigated represent ores formed via different modes of mineralization (e.g., high- and low-temperature) and within various geological contexts, which include magmatic pegmatites, metamorphic rocks, sandstone-hosted, and roll front deposits. In situ trace element data obtained by laser ablation-ICP-MS and bulk sample Sr isotopic ratios for uraninite samples investigated here indicate distinct signatures that are highly dependent on the mode of mineralization and host rock geology. Relativemore » to their high-temperature counterparts, low-temperature uranium ores record high U/Th ratios (>1000), low total rare earth element (REE) abundances (<1 wt%), high contents (>300 ppm) of first row transition metals (Sc, Ti, V, Cr, Mn, Co, Ni), and radiogenic 87Sr/ 86Sr ratios (>0.7200). Comparison of chondrite normalized REE patterns between uraninite and corresponding processed UOC from the same locality indicates identical patterns at different absolute concentrations. Lastly, this result ultimately confirms the importance of establishing geochemical signatures of raw, uranium ore materials for attribution purposes in the forensic analysis of intercepted nuclear materials.« less

Socioenvironmental factors associated with heat and cold-related mortality in Vadu HDSS, western India: a population-based case-crossover study

NASA Astrophysics Data System (ADS)

Ingole, Vijendra; Kovats, Sari; Schumann, Barbara; Hajat, Shakoor; Rocklöv, Joacim; Juvekar, Sanjay; Armstrong, Ben

2017-10-01

Ambient temperatures (heat and cold) are associated with mortality, but limited research is available about groups most vulnerable to these effects in rural populations. We estimated the effects of heat and cold on daily mortality among different sociodemographic groups in the Vadu HDSS area, western India. We studied all deaths in the Vadu HDSS area during 2004-2013. A conditional logistic regression model in a case-crossover design was used. Separate analyses were carried out for summer and winter season. Odds ratios (OR) and 95% confidence intervals (CI) were estimated for total mortality and population subgroups. Temperature above a threshold of 31 °C was associated with total mortality (OR 1.48, CI = 1.05-2.09) per 1 °C increase in daily mean temperature. Odds ratios were higher among females (OR 1.93; CI = 1.07-3.47), those with low education (OR 1.65; CI = 1.00-2.75), those owing larger agricultural land (OR 2.18; CI = 0.99-4.79), and farmers (OR 1.70; CI = 1.02-2.81). In winter, per 1 °C decrease in mean temperature, OR for total mortality was 1.06 (CI = 1.00-1.12) in lag 0-13 days. High risk of cold-related mortality was observed among people occupied in housework (OR = 1.09; CI = 1.00-1.19). Our study suggests that both heat and cold have an impact on mortality particularly heat, but also, to a smaller degree, cold have an impact. The effects may differ partly by sex, education, and occupation. These findings might have important policy implications in preventing heat and cold effects on particularly vulnerable groups of the rural populations in low and middle-income countries with hot semi-arid climate.

The carrier gas pressure effect in a laminar flow diffusion chamber, homogeneous nucleation of n-butanol in helium.

PubMed

Hyvärinen, Antti-Pekka; Brus, David; Zdímal, Vladimír; Smolík, Jiri; Kulmala, Markku; Viisanen, Yrjö; Lihavainen, Heikki

2006-06-14

Homogeneous nucleation rate isotherms of n-butanol+helium were measured in a laminar flow diffusion chamber at total pressures ranging from 50 to 210 kPa to investigate the effect of carrier gas pressure on nucleation. Nucleation temperatures ranged from 265 to 280 K and the measured nucleation rates were between 10(2) and 10(6) cm(-3) s(-1). The measured nucleation rates decreased as a function of increasing pressure. The pressure effect was strongest at pressures below 100 kPa. This negative carrier gas effect was also temperature dependent. At nucleation temperature of 280 K and at the same saturation ratio, the maximum deviation between nucleation rates measured at 50 and 210 kPa was about three orders of magnitude. At nucleation temperature of 265 K, the effect was negligible. Qualitatively the results resemble those measured in a thermal diffusion cloud chamber. Also the slopes of the isothermal nucleation rates as a function of saturation ratio were different as a function of total pressure, 50 kPa isotherms yielded the steepest slopes, and 210 kPa isotherms the shallowest slopes. Several sources of inaccuracies were considered in the interpretation of the results: uncertainties in the transport properties, nonideal behavior of the vapor-carrier gas mixture, and shortcomings of the used mathematical model. Operation characteristics of the laminar flow diffusion chamber at both under-and over-pressure were determined to verify a correct and stable operation of the device. We conclude that a negative carrier gas pressure effect is seen in the laminar flow diffusion chamber and it cannot be totally explained with the aforementioned reasons.

Low temperature photochemical vapor deposition of alloy and mixed metal oxide films

DOEpatents

Liu, David K.

1992-01-01

Method and apparatus for formation of an alloy thin film, or a mixed metal oxide thin film, on a substrate at relatively low temperatures. Precursor vapor(s) containing the desired thin film constituents is positioned adjacent to the substrate and irradiated by light having wavelengths in a selected wavelength range, to dissociate the gas(es) and provide atoms or molecules containing only the desired constituents. These gases then deposit at relatively low temperatures as a thin film on the substrate. The precursor vapor(s) is formed by vaporization of one or more precursor materials, where the vaporization temperature(s) is selected to control the ratio of concentration of metals present in the precursor vapor(s) and/or the total precursor vapor pressure.

How Does Temperature Impact Leaf Size and Shape in Four Woody Dicot Species? Testing the Assumptions of Leaf Physiognomy-Climate Models

NASA Astrophysics Data System (ADS)

McKee, M.; Royer, D. L.

2017-12-01

The physiognomy (size and shape) of fossilized leaves has been used to reconstruct the mean annual temperature of ancient environments. Colder temperatures often select for larger and more abundant leaf teeth—serrated edges on leaf margins—as well as a greater degree of leaf dissection. However, to be able to accurately predict paleotemperature from the morphology of fossilized leaves, leaves must be able to react quickly and in a predictable manner to changes in temperature. We examined the extent to which temperature affects leaf morphology in four tree species: Carpinus caroliniana, Acer negundo, Ilex opaca, and Ostrya virginiana. Saplings of these species were grown in two growth cabinets under contrasting temperatures (17 and 25 °C). Compared to the cool treatment, in the warm treatment Carpinus caroliniana leaves had significantly fewer leaf teeth and a lower ratio of total number of leaf teeth to internal perimeter; and Acer negundo leaves had a significantly lower feret diameter ratio (a measure of leaf dissection). In addition, a two-way ANOVA tested the influence of temperature and species on leaf physiognomy. This analysis revealed that all plants, regardless of species, tended to develop more highly dissected leaves with more leaf teeth in the cool treatment. Because the cabinets maintained equivalent moisture, humidity, and CO2 concentration between the two treatments, these results demonstrate that these species could rapidly adapt to changes in temperature. However, not all of the species reacted identically to temperature changes. For example, Acer negundo, Carpinus caroliniana, and Ostrya virginiana all had a higher number of total teeth in the cool treatment compared to the warm treatment, but the opposite was true for Ilex opaca. Our work questions a fundamental assumption common to all models predicting paleotemperature from the physiognomy of fossilized leaves: a given climate will inevitably select for the same leaf physiognomy, regardless of species composition. To more accurately compensate for differences among species, models should incorporate phylogenetic information.

Toxic Cyanobacterial Bloom Triggers in Missisquoi Bay, Lake Champlain, as Determined by Next-Generation Sequencing and Quantitative PCR

PubMed Central

Fortin, Nathalie; Munoz-Ramos, Valentina; Bird, David; Lévesque, Benoît; Whyte, Lyle G.; Greer, Charles W.

2015-01-01

Missisquoi Bay (MB) is a temperate eutrophic freshwater lake that frequently experiences toxic Microcystis-dominated cyanobacterial blooms. Non-point sources are responsible for the high concentrations of phosphorus and nitrogen in the bay. This study combined data from environmental parameters, E. coli counts, high-throughput sequencing of 16S rRNA gene amplicons, quantitative PCR (16S rRNA and mcyD genes) and toxin analyses to identify the main bloom-promoting factors. In 2009, nutrient concentrations correlated with E. coli counts, abundance of total cyanobacterial cells, Microcystis 16S rRNA and mcyD genes and intracellular microcystin. Total and dissolved phosphorus also correlated significantly with rainfall. The major cyanobacterial taxa were members of the orders Chroococcales and Nostocales. The genus Microcystis was the main mcyD-carrier and main microcystin producer. Our results suggested that increasing nutrient concentrations and total nitrogen:total phosphorus (TN:TP) ratios approaching 11:1, coupled with an increase in temperature, promoted Microcystis-dominated toxic blooms. Although the importance of nutrient ratios and absolute concentrations on cyanobacterial and Microcystis dynamics have been documented in other laboratories, an optimum TN:TP ratio for Microcystis dominance has not been previously observed in situ. This observation provides further support that nutrient ratios are an important determinant of species composition in natural phytoplankton assemblages. PMID:25984732

Simulation of ideal-gas flow by nitrogen and other selected gases at cryogenic temperatures. [transonic flow in cryogenic wind tunnels

NASA Technical Reports Server (NTRS)

Hall, R. M.; Adcock, J. B.

1981-01-01

The real gas behavior of nitrogen, the gas normally used in transonic cryogenic tunnels, is reported for the following flow processes: isentropic expansion, normal shocks, boundary layers, and interactions between shock waves and boundary layers. The only difference in predicted pressure ratio between nitrogen and an ideal gas which may limit the minimum operating temperature of transonic cryogenic wind tunnels occur at total pressures approaching 9 atm and total temperatures 10 K below the corresponding saturation temperature. These pressure differences approach 1 percent for both isentropic expansions and normal shocks. Alternative cryogenic test gases were also analyzed. Differences between air and an ideal diatomic gas are similar in magnitude to those for nitrogen and should present no difficulty. However, differences for helium and hydrogen are over an order of magnitude greater than those for nitrogen or air. It is concluded that helium and cryogenic hydrogen would not approximate the compressible flow of an ideal diatomic gas.

A physical parameter method for the design of broad-band X-ray imaging systems to do coronal plasma diagnostics

NASA Technical Reports Server (NTRS)

Kahler, S.; Krieger, A. S.

1978-01-01

The technique commonly used for the analysis of data from broad-band X-ray imaging systems for plasma diagnostics is the filter ratio method. This requires the use of two or more broad-band filters to derive temperatures and line-of-sight emission integrals or emission measure distributions as a function of temperature. Here an alternative analytical approach is proposed in which the temperature response of the imaging system is matched to the physical parameter being investigated. The temperature response of a system designed to measure the total radiated power along the line of sight of any coronal structure is calculated. Other examples are discussed.

Effect of area ratio on the performance of a 5.5:1 pressure ratio centrifugal impeller

NASA Technical Reports Server (NTRS)

Schumann, L. F.; Clark, D. A.; Wood, J. R.

1986-01-01

A centrifugal impeller which was initially designed for a pressure ratio of approximately 5.5 and a mass flow rate of 0.959 kg/sec was tested with a vaneless diffuser for a range of design point impeller area ratios from 2.322 to 2.945. The impeller area ratio was changed by successively cutting back the impeller exit axial width from an initial value of 7.57 mm to a final value of 5.97 mm. In all, four separate area ratios were tested. For each area ratio a series of impeller exit axial clearances was also tested. Test results are based on impeller exit surveys of total pressure, total temperature, and flow angle at a radius 1.115 times the impeller exit radius. Results of the tests at design speed, peak efficiency, and an exit tip clearance of 8 percent of exit blade height show that the impeller equivalent pressure recovery coefficient peaked at a design point area ratio of approximately 2.748 while the impeller aerodynamic efficiency peaked at a lower value of area ratio of approximately 2.55. The variation of impeller efficiency with clearance showed expected trends with a loss of approximately 0.4 points in impeller efficiency for each percent increase in exit axial tip clearance for all impellers tested.

Catalytic fast co-pyrolysis of biomass and food waste to produce aromatics: Analytical Py-GC/MS study.

PubMed

Zhang, Bo; Zhong, Zhaoping; Min, Min; Ding, Kuan; Xie, Qinglong; Ruan, Roger

2015-01-01

In this study, catalytic fast co-pyrolysis (co-CFP) of corn stalk and food waste (FW) was carried out to produce aromatics using quantitative pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS), and ZSM-5 zeolite in the hydrogen form was employed as the catalyst. Co-CFP temperature and a parameter called hydrogen to carbon effective ratio (H/C(eff) ratio) were examined for their effects on the relative content of aromatics. Experimental results showed that co-CFP temperature of 600 °C was optimal for the formation of aromatics and other organic pyrolysis products. Besides, H/C(eff) ratio had an important influence on product distribution. The yield of total organic pyrolysis products and relative content of aromatics increased non-linearly with increasing H/C(eff) ratio. There was an apparent synergistic effect between corn stalk and FW during co-CFP process, which promoted the production of aromatics significantly. Co-CFP of biomass and FW was an effective method to produce aromatics and other petrochemicals. Copyright © 2015. Published by Elsevier Ltd.

Efficiency optimization of a closed indirectly fired gas turbine cycle working under two variable-temperature heat reservoirs

NASA Astrophysics Data System (ADS)

Ma, Zheshu; Wu, Jieer

2011-08-01

Indirectly or externally fired gas turbines (IFGT or EFGT) are interesting technologies under development for small and medium scale combined heat and power (CHP) supplies in combination with micro gas turbine technologies. The emphasis is primarily on the utilization of the waste heat from the turbine in a recuperative process and the possibility of burning biomass even "dirty" fuel by employing a high temperature heat exchanger (HTHE) to avoid the combustion gases passing through the turbine. In this paper, finite time thermodynamics is employed in the performance analysis of a class of irreversible closed IFGT cycles coupled to variable temperature heat reservoirs. Based on the derived analytical formulae for the dimensionless power output and efficiency, the efficiency optimization is performed in two aspects. The first is to search the optimum heat conductance distribution corresponding to the efficiency optimization among the hot- and cold-side of the heat reservoirs and the high temperature heat exchangers for a fixed total heat exchanger inventory. The second is to search the optimum thermal capacitance rate matching corresponding to the maximum efficiency between the working fluid and the high-temperature heat reservoir for a fixed ratio of the thermal capacitance rates of the two heat reservoirs. The influences of some design parameters on the optimum heat conductance distribution, the optimum thermal capacitance rate matching and the maximum power output, which include the inlet temperature ratio of the two heat reservoirs, the efficiencies of the compressor and the gas turbine, and the total pressure recovery coefficient, are provided by numerical examples. The power plant configuration under optimized operation condition leads to a smaller size, including the compressor, turbine, two heat reservoirs and the HTHE.

Factors affecting water resistance of alginate/gellan blend films on paper cups for hot drinks.

PubMed

Zhang, Ning; Xu, Jiachao; Gao, Xin; Fu, Xiaoting; Zheng, Di

2017-01-20

Enhanced film water resistance of paper cups was achieved by physically blending sodium alginate (NaAlg) and gellan gum with crosslinking treatment. Pure and blended films were prepared and characterized via Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), differential scanning calorimetry (DSC), and positron annihilation lifetime spectroscopy (PALS). Results demonstrated excellent compatibility between the two polysaccharides. Total mixed solution concentration, component ratio, glycerol content, Ca 2+ concentration, crosslinking time, and dry temperature affected water resistance. Water permeability (WP) and swelling degree (SD) were tested. Optimal conditions were as follows: total mixed solution concentration, 2.4% (m/v); component ratio, 2:1; glycerol content, 0.5% (m/v); Ca 2+ concentration, 5% (m/v); crosslinking time, 5min; and dry temperature, 50°C. WP and SD values were 78.1×10 -8 g/msPa and 66.3%, respectively. Properties of the films showed the synergistic effect between NaAlg and gellan, which can be used for water-resistant film coating on paper cups for hot drinks. Copyright © 2016 Elsevier Ltd. All rights reserved.

Rapid mineralisation of the Organic Fraction of Municipal Solid Waste.

PubMed

Martínez-Valdez, F J; Martínez-Ramírez, C; Martínez-Montiel, L; Favela-Torres, E; Soto-Cruz, N O; Ramírez-Vives, F; Saucedo-Castañeda, G

2015-03-01

The effect of pH, C/N ratio, addition of a microbial consortium (MC) and temperature upon mineralisation of Organic Fraction of Municipal Solid Waste (OFMSW) was studied; mineralisation was measured through the CO2 production rate and total CO2 formation. Through this process up to 432.9mg of CO2g(-1) initial dry matter (IDM) after 2days of treatment was obtained. It was found that under a slightly acidic pH (5-6) and C/N of 30, the mineralisation process was accelerated. Moreover, temperature (27-50°C) had no effect on the total CO2 produced. The highest CO2 production rate (5.28d(-1)) was observed at 27°C, C/N ratio of 30 and 8% of microbial consortium; it is at least 3.52 times higher than that reported (1.5d(-1)). The highest release of reducing sugars was determined at 50°C, possibly due to an increase in hydrolytic enzymes. Results suggest the potential use of rapid mineralisation of OFMSW for further friendly environmental processes. Copyright © 2014 Elsevier Ltd. All rights reserved.

Identification and characterization of hydrocolloid from Cordia myxa leaf.

PubMed

Samavati, Vahid; Lorestani, Mohammad; Joolazadeh, Sajjad

2014-04-01

Hot water extraction technique was employed to extract the hydrocolloid from Cordia myxa leaf (PCM). The optimal conditions for extraction of PCM were determined using response surface methodology. A Box-Behnken design (BBD) was applied to evaluate the effects of three independent variables (extraction time (X1: 1-4 h), extraction temperature (X2: 55-95 °C), and water to raw material ratio (X3: 5-30 ml/g) on the extraction yield of PCM. The content of moisture, water-soluble and water-insoluble ash, crude protein and total phenol were determined in the extracted hydrocolloid by standard methods. The maximum hydrocolloid extraction yield (9.501±0.15%) was achieved by using extraction time of 4.94 h, extraction temperature of 94.91 °C and water to raw material ratio of 21.74 ml/g. The contents of moisture, crude protein, water-soluble and water-insoluble ash and total phenol were 21.63±0.94%, 14.27±0.55%, 3.07±0.16% and 2.61±0.19 mg galic acid/g, respectively. Copyright © 2014 Elsevier B.V. All rights reserved.

Magnetic and lattice contributions to the magnetocaloric effect in Sm1-xSrxMnO3 manganites

NASA Astrophysics Data System (ADS)

Aliev, A. M.; Batdalov, A. B.; Khanov, L. N.

2018-04-01

A method is proposed to estimate the lattice and magnetic contributions to the total magnetocaloric effect (MCE) in materials with magnetostructural phase transitions. The method is based on two assumptions: (a) the lattice contribution is proportional to magnetostriction and (b) the magnetic contribution obeys a field dependence ΔTm ˜ Hn. Temperature and magnetic field dependences of the MCE and magnetostriction are used to estimate the contributions. Estimations of the contributions in Sm0.6Sr0.4MnO3 manganite are made for cases when n = 0.66 and n = 0.75. Analysis shows that in the area of the maximum of the effect for n = 0.66, the magnetic subsystem contributes about 58% of the total MCE, and the remaining 42% are due to a change in the entropy of the lattice. In the case of n = 0.75, the magnetic contribution remains predominant, but the ratio of the contributions changes: the magnetic contribution counts for 53% and the lattice contribution equals to 47%. The ratio of contributions varies with the temperature and magnetic field. The results of estimation agree with direct measurements of the MCE in Sm0.5Sr0.5MnO3 manganite, where almost the total effect is due to a change in the magnetic entropy.

Optimization of antioxidant and antiglycated activities of polysaccharides from Arthrocnemum indicum leaves.

PubMed

Mzoughi, Zeineb; Chaouch, Mohamed Aymen; Hammi, Khaoula Mkadmini; Hafsa, Jawhar; Le Cerf, Didier; Ksouri, Riadh; Majdoub, Hatem

2018-07-01

Central composite design was performed to optimize uronic acid rate, esterification degree, total antioxidant ability and antiglycation capacity of carbohydrates from Arthrocnemum indicum leaves. Three independent variables were opted: extraction temperature, time and ratio (solvent/material). The optimal settings were: extraction temperature of 80°C, time of 288min and (solvent/solid) ratio of 40mL/g. Under these settings, uronic acid rate and esterification degree were 49.29%, 30.24%, respectively, whereas total antioxidant activity and antiglycation capacity was 35.81mg ascorbic acid equivalents/g matter and 69.81%, respectively. Colorimetric assays showed that total sugar and uronic acid contents for polysaccharide were 71.78% and 49.24%, respectively. Furthermore, Preliminary structure study was performed via various methods including FT-IR, NMR and UV-vis analysis. SEC analyzes revealed that polysaccharide had an average molecular weight of 2179kDa. Moreover, GC-MS analyzes showed that extracted polysaccharide was a pectic polysaccharide which formed of arabinose, mannose, galactose, rhamnose, glucose and xylose in the molar percentage of 66.68%, 3.93%, 12.71%, 6.31%, 6.08% and 4.29%, respectively. This results revealed that extracted polysaccharide can be employed as source of natural antioxidants and as possible antiglycated agents. Copyright © 2018 Elsevier B.V. All rights reserved.

The impact of different cooling strategies on urban air temperatures: the cases of Campinas, Brazil and Mendoza, Argentina

NASA Astrophysics Data System (ADS)

Alchapar, Noelia Liliana; Pezzuto, Claudia Cotrim; Correa, Erica Norma; Chebel Labaki, Lucila

2017-10-01

This paper describes different ways of reducing urban air temperature and their results in two cities: Campinas, Brazil—a warm temperate climate with a dry winter and hot summer (Cwa), and Mendoza, Argentina—a desert climate with cold steppe (BWk). A high-resolution microclimate modeling system—ENVI-met 3.1—was used to evaluate the thermal performance of an urban canyon in each city. A total of 18 scenarios were simulated including changes in the surface albedo, vegetation percentage, and the H/W aspect ratio of the urban canyons. These results revealed the same trend in behavior for each of the combinations of strategies evaluated in both cities. Nevertheless, these strategies produce a greater temperature reduction in the warm temperate climate (Cwa). Increasing the vegetation percentage reduces air temperatures and mean radiant temperatures in all scenarios. In addition, there is a greater decrease of urban temperature with the vegetation increase when the H/W aspect ratio is lower. Also, applying low albedo on vertical surfaces and high albedo on horizontal surfaces is successful in reducing air temperatures without raising the mean radiant temperature. The best combination of strategies—60 % of vegetation, low albedos on walls and high albedos on pavements and roofs, and 1.5 H/W—could reduce air temperatures up to 6.4 °C in Campinas and 3.5 °C in Mendoza.

Space Based Observations of Coronal Cavities in Conjunction with the Total Solar Eclipse of July 2010

NASA Technical Reports Server (NTRS)

Kucera, T. A.; Berger, T. E.; Druckmuller, M.; Dietzel, M.; Gibson, S. E.; Habbal, S. R.; Morgan, H.; Reeves, K. K.; Schmit, D. J.; Seaton, D. B.

2010-01-01

In conjunction with the total solar eclipse on July 11, 2010 we coordinated a campaign between ground and space based observations. Our specific goal was to augment the ground based measurement of corona) prominence cavity temperatures made using iron lines in the IR (Habbal et al. 2010 ApJ 719 1362) with measurements performed by space based instruments. Included in the campaign were Hinode/EIS, XRT and SOT, PROBA2/SWAP, SDO/AIA, SOHO/CDS and STEREO/SECCHI/EUVI, in addition to the ground based IR measurements. We plan to use a combination of line ratio and forward modeling techniques to investigate the density and temperature structure of the cavities at that time.

High-Area-Ratio Rocket Nozzle at High Combustion Chamber Pressure: Experimental and Analytical Validation

NASA Technical Reports Server (NTRS)

Jankovsky, Robert S.; Smith, Timothy D.; Pavli, Albert J.

1999-01-01

Experimental data were obtained on an optimally contoured nozzle with an area ratio of 1025:1 and on a truncated version of this nozzle with an area ratio of 440:1. The nozzles were tested with gaseous hydrogen and liquid oxygen propellants at combustion chamber pressures of 1800 to 2400 psia and mixture ratios of 3.89 to 6.15. This report compares the experimental performance, heat transfer, and boundary layer total pressure measurements with theoretical predictions of the current Joint Army, Navy, NASA, Air Force (JANNAF) developed methodology. This methodology makes use of the Two-Dimensional Kinetics (TDK) nozzle performance code. Comparisons of the TDK-predicted performance to experimentally attained thrust performance indicated that both the vacuum thrust coefficient and the vacuum specific impulse values were approximately 2.0-percent higher than the turbulent prediction for the 1025:1 configurations, and approximately 0.25-percent higher than the turbulent prediction for the 440:1 configuration. Nozzle wall temperatures were measured on the outside of a thin-walled heat sink nozzle during the test fittings. Nozzle heat fluxes were calculated front the time histories of these temperatures and compared with predictions made with the TDK code. The heat flux values were overpredicted for all cases. The results range from nearly 100 percent at an area ratio of 50 to only approximately 3 percent at an area ratio of 975. Values of the integral of the heat flux as a function of nozzle surface area were also calculated. Comparisons of the experiment with analyses of the heat flux and the heat rate per axial length also show that the experimental values were lower than the predicted value. Three boundary layer rakes mounted on the nozzle exit were used for boundary layer measurements. This arrangement allowed total pressure measurements to be obtained at 14 different distances from the nozzle wall. A comparison of boundary layer total pressure profiles and analytical predictions show good agreement for the first 0.5 in. from the nozzle wall; but the further into the core flow that measurements were taken, the more that TDK overpredicted the boundary layer thickness.

Computer Mapping of Water Quality in Saginaw Bay with LANDSAT Digital Data

NASA Technical Reports Server (NTRS)

Rogers, R. H. (Principal Investigator); Shah, N. J.; Smith, V. E.; Mckeon, J. B.

1976-01-01

The author has identified the following significant results. LANDSAT digital data and ground truth measurements for Saginaw Bay (Lake Huron), Michigan, for 31 July 1975 were correlated by stepwise linear regression and the resulting equations used to estimate invisible water quality parameters in nonsampled areas. Chloride, conductivity, total Kjeldahl nitrogen, total phosphorus, and chlorophyll a were best correlated with the ratio of LANDSAT Band 4 to Band 5. Temperature and Secchi depth correlate best with Band 5.

Sensitivity Studies for Space-based Measurements of Atmospheric Total Column Carbon Dioxide Using Reflected Sunlight

NASA Technical Reports Server (NTRS)

Mao, Jianping; Kawa, S. Randolph

2003-01-01

A series of sensitivity studies is carried out to explore the feasibility of space-based global carbon dioxide (CO2) measurements for global and regional carbon cycle studies. The detection method uses absorption of reflected sunlight in the CO2 vibration-rotation band at 1.58 micron. The sensitivities of the detected radiances are calculated using the line-by-line model (LBLRTM), implemented with the DISORT (Discrete Ordinates Radiative Transfer) model to include atmospheric scattering in this band. The results indicate that (a) the small (approx.1%) changes in CO2 near the Earth's surface are detectable in this CO2 band provided adequate sensor signal-to-noise ratio and spectral resolution are achievable; (b) the effects of other interfering constituents, such as water vapor, aerosols and cirrus clouds, on the radiance are significant but the overall effects of the modification of light path length on total back-to-space radiance sensitivity to CO2 change are minor for general cases, which means that generally the total column CO2 can be derived in high precision from the ratio of the on-line center to off-line radiances; (c) together with CO2 gas absorption aerosol/cirrus cloud layer has differential scattering which may result in the modification of on-line to off-line radiance ratio which could lead a large bias in the total column CO2 retrieval. Approaches to correct such bias need further investigation. (d) CO2 retrieval requires good knowledge of the atmospheric temperature profile, e.g. approximately 1K RMS error in layer temperature, which is achievable from new atmospheric sounders in the near future; (e) the atmospheric path length, over which the CO2 absorption occurs, should be known in order to correctly interpret horizontal gradients of CO2 from the total column CO2 measurement; thus an additional sensor for surface pressure measurement needs to be attached for a complete measurement package.

Ultra-high Temperature Emittance Measurements for Space and Missile Applications

NASA Technical Reports Server (NTRS)

Rogers, Jan; Crandall, David

2009-01-01

Advanced modeling and design efforts for many aerospace components require high temperature emittance data. Applications requiring emittance data include propulsion systems, radiators, aeroshells, heatshields/thermal protection systems, and leading edge surfaces. The objective of this work is to provide emittance data at ultra-high temperatures. MSFC has a new instrument for the measurement of emittance at ultra-high temperatures, the Ultra-High Temperature Emissometer System (Ultra-HITEMS). AZ Technology Inc. developed the instrument, designed to provide emittance measurements over the temperature range 700-3500K. The Ultra-HITEMS instrument measures the emittance of samples, heated by lasers, in vacuum, using a blackbody source and a Fourier Transform Spectrometer. Detectors in a Nicolet 6700 FT-IR spectrometer measure emittance over the spectral range of 0.4-25 microns. Emitted energy from the specimen and output from a Mikron M390S blackbody source at the same temperature with matched collection geometry are measured. Integrating emittance over the spectral range yields the total emittance. The ratio provides a direct measure of total hemispherical emittance. Samples are heated using lasers. Optical pyrometry provides temperature data. Optical filters prevent interference from the heating lasers. Data for Inconel 718 show excellent agreement with results from literature and ASTM 835. Measurements taken from levitated spherical specimens provide total hemispherical emittance data; measurements taken from flat specimens mounted in the chamber provide near-normal emittance data. Data from selected characterization studies will be presented. The Ultra-HITEMS technique could advance space and missile technologies by advancing the knowledge base and the technology readiness level for ultra-high temperature materials.

Organic matter geochemical signatures (TOC, TN, C/N ratio, δ13C and δ15N) of surface sediment from lakes distributed along a climatological gradient on the western side of the southern Andes.

PubMed

Contreras, Sergio; Werne, Josef P; Araneda, A; Urrutia, R; Conejero, C A

2018-07-15

Paleolimnological studies in western South America, where meteorological stations are scarce, are critical to obtain more realistic and reliable regional reconstructions of past climate and environmental changes, including vegetation and water budget variability. However, climate and environmental geochemical indicators must be tested before they can be applied with confidence. Here we present a survey of lacustrine surface sediment (core top, 0 to ~1cm) biogeochemical proxies (total organic carbon [TOC], total nitrogen [TN], carbon/nitrogen ratio [C/N ratio] and bulk organic δ 13 C and total δ 15 N) from a suite of 72 lakes spanning the transition from a Mediterranean climate with a patchwork of cultivated vegetation, pastureland, and conifers in central Chile to a rainy temperate climate dominated by broadleaf deciduous and evergreen forest further south. Sedimentary data are compared to the latitudinal and orographic climatic trends of the region based on the climatology (precipitation and temperature) produced with Climate Forecast System Reanalysis (CFSR) data and the modern Southern Hemisphere Westerly Winds (SWW) location. The geochemical data show inflection points at ~42°S latitude and ~1500m elevation that are likely related to the northern limit of influence of the SWW and elevation of the snow line, respectively. Overall the organic proxies were able to mimic climatic trends (Mean Annual Precipitation [MAP] and temperature [MAT]), indicating that they are a useful tool to be included in paleoclimatological reconstruction of the region. Copyright © 2018 Elsevier B.V. All rights reserved.

Application of LANDSAT to the surveillance and control of lake eutrophication in the Great Lakes basin. [Saginaw Bay, Michigan and Wisconsin

NASA Technical Reports Server (NTRS)

Rogers, R. H. (Principal Investigator)

1976-01-01

The author has identified the following significant results. Computer techniques were developed for mapping water quality parameters from LANDSAT data, using surface samples collected in an ongoing survey of water quality in Saginaw Bay. Chemical and biological parameters were measured on 31 July 1975 at 16 bay stations in concert with the LANDSAT overflight. Application of stepwise linear regression bands to nine of these parameters and corresponding LANDSAT measurements for bands 4 and 5 only resulted in regression correlation coefficients that varied from 0.94 for temperature to 0.73 for Secchi depth. Regression equations expressed with the pair of bands 4 and 5, rather than the ratio band 4/band 5, provided higher correlation coefficients for all the water quality parameters studied (temperature, Secchi depth, chloride, conductivity, total kjeldahl nitrogen, total phosphorus, chlorophyll a, total solids, and suspended solids).

Cosmological constraints from galaxy clustering in the presence of massive neutrinos

NASA Astrophysics Data System (ADS)

Zennaro, M.; Bel, J.; Dossett, J.; Carbone, C.; Guzzo, L.

2018-06-01

The clustering ratio is defined as the ratio between the correlation function and the variance of the smoothed overdensity field. In Λ cold dark matter (ΛCDM) cosmologies without massive neutrinos, it has already been proven to be independent of bias and redshift space distortions on a range of linear scales. It therefore can provide us with a direct comparison of predictions (for matter in real space) against measurements (from galaxies in redshift space). In this paper we first extend the applicability of such properties to cosmologies that account for massive neutrinos, by performing tests against simulated data. We then investigate the constraining power of the clustering ratio on cosmological parameters such as the total neutrino mass and the equation of state of dark energy. We analyse the joint posterior distribution of the parameters that satisfy both measurements of the galaxy clustering ratio in the SDSS-DR12, and the angular power spectra of cosmic microwave background temperature and polarization anisotropies measured by the Planck satellite. We find the clustering ratio to be very sensitive to the CDM density parameter, but less sensitive to the total neutrino mass. We also forecast the constraining power the clustering ratio will achieve, predicting the amplitude of its errors with a Euclid-like galaxy survey. First we compute parameter forecasts using the Planck covariance matrix alone, then we add information from the clustering ratio. We find a significant improvement on the constraint of all considered parameters, and in particular an improvement of 40 per cent for the CDM density and 14 per cent for the total neutrino mass.

Influence of temperature gradients on charge transport in asymmetric nanochannels.

PubMed

Benneker, Anne M; Wendt, Hans David; Lammertink, Rob G H; Wood, Jeffery A

2017-10-25

Charge selective asymmetric nanochannels are used for a variety of applications, such as nanofluidic sensing devices and energy conversion applications. In this paper, we numerically investigate the influence of an applied temperature difference over tapered nanochannels on the resulting charge transport and flow behavior. Using a temperature-dependent formulation of the coupled Poisson-Nernst-Planck and Navier-Stokes equations, various nanochannel geometries are investigated. Temperature has a large influence on the total ion transport, as the diffusivity of ions and viscosity of the solution are strongly affected by temperature. We find that the selectivity of the nanochannels is enhanced with increasing asymmetry ratios, while the total current is reduced at higher asymmetry cases. Most interestingly, we find that applying a temperature gradient along the electric field and along the asymmetry direction of the nanochannel enhances the selectivity of the tapered channels even further, while a temperature gradient countering the electric field reduces the selectivity of the nanochannel. Current rectification is enhanced in asymmetric nanochannels if a temperature gradient is applied, independent of the direction of the temperature difference. However, the degree of rectification is dependent on the direction of the temperature gradient with respect to the channel geometry and the electric field direction. The enhanced selectivity of nanochannels due to applied temperature gradients could result in more efficient operation in energy harvesting or desalination applications, motivating experimental investigations.

Characterization and open windrow composting of MSW in Jodhpur City, Rajasthan, India.

PubMed

Ambade, Bhushan; Sharma, Sunil; Sharma, Yukti; Sharma, Yagya

2013-07-01

Solid waste is sometimes not suitable for direct land application. Processing solid waste through composting converts it to a humus-containing organic material advantageous for agriculture/horticulture use. Major advantages of composting are stabilization of the wastes; substantially reduced C/N ratio and gas formation, and virtually elimination of odors and pathogens. Composting is accomplished under aerobic conditions developing temperatures of 55 degrees C or above. The windrow technique is simple and accomplished easily with standard equipments. The open windrow composting of municipal solid waste (MSW) in windrows was analyzed in this study for six weeks. The raw MSW was introduced to active composting without any source segregations. The moisture content of the MSW dropped from 58.88% to 48.06% and windrow attained a thermophillic temperature for about two weeks. It was observed that the pH, C/N ratio and temperature variations were comparable to that of traditional windrow composting. The peak temperature recorded was 68 degrees C and temperature remained above 60 degrees C for more than three weeks. The volume reduction was obtained by using one-cu.m. cage. The results indicate that the bulk composting could reduce by about 29% the total mass of the waste.

Symmetric Anderson impurity model: Magnetic susceptibility, specific heat and Wilson ratio

NASA Astrophysics Data System (ADS)

Zalom, Peter; Pokorný, Vladislav; Janiš, Václav

2018-05-01

We extend the spin-polarized effective-interaction approximation of the parquet renormalization scheme from Refs. [1,2] applied on the symmetric Anderson model by adding the low-temperature asymptotics of the total energy and the specific heat. We calculate numerically the Wilson ratio and determine analytically its asymptotic value in the strong-coupling limit. We demonstrate in this way that the exponentially small Kondo scale from the strong-coupling regime emerges in qualitatively the same way in the spectral function, magnetic susceptibility and the specific heat.

The influence of the Ar/O2 ratio on the electron density and electron temperature in microwave discharges

NASA Astrophysics Data System (ADS)

Espinho, S.; Hofmann, S.; Palomares, J. M.; Nijdam, S.

2017-10-01

The aim of this work is to study the properties of Ar-O2 microwave driven surfatron plasmas as a function of the Ar/O2 ratio in the gas mixture. The key parameters are the plasma electron density and electron temperature, which are estimated with Thomson scattering (TS) for O2 contents up to 50% of the total gas flow. A sharp drop in the electron density from {10}20 {{{m}}}-3 to approximately {10}18 {{{m}}}-3 is estimated as the O2 content in the gas mixture is increased up to 15%. For percentages of O2 lower than 10%, the electron temperature is estimated to be about 2-3 times higher than in the case of a pure argon discharge in the same conditions ({T}{{e}}≈ 1 eV) and gradually decreases as the O2 percentage is raised to 50%. However, for O2 percentages above 30%, the scattering spectra become Raman dominated, resulting in large uncertainties in the estimated electron densities and temperatures. The influence of photo-detached electrons from negative ions caused by the typical TS laser fluences is also likely to contribute to the uncertainty in the measured electron densities for high O2 percentages. Moreover, the detection limit of the system is reached for percentages of O2 higher than 25%. Additionally, both the electron density and temperature of microwave discharges with large Ar/O2 ratios are more sensitive to gas pressure variations.

Low temperature photochemical vapor deposition of alloy and mixed metal oxide films

DOEpatents

Liu, D.K.

1992-12-15

Method and apparatus are described for formation of an alloy thin film, or a mixed metal oxide thin film, on a substrate at relatively low temperatures. Precursor vapor(s) containing the desired thin film constituents is positioned adjacent to the substrate and irradiated by light having wavelengths in a selected wavelength range, to dissociate the gas(es) and provide atoms or molecules containing only the desired constituents. These gases then deposit at relatively low temperatures as a thin film on the substrate. The precursor vapor(s) is formed by vaporization of one or more precursor materials, where the vaporization temperature(s) is selected to control the ratio of concentration of metals present in the precursor vapor(s) and/or the total precursor vapor pressure. 7 figs.

Development of self-healing polymers via amine-epoxy chemistry: II. Systematic evaluation of self-healing performance

NASA Astrophysics Data System (ADS)

Zhang, He; Yang, Jinglei

2014-06-01

Part I of this study (H Zhang and J Yang 2014 Smart Mater. Struct. 23 065003) reported the preparation and characterization of epoxy microcapsules (EP-capsules) and amine loaded hollow glass bubbles (AM-HGBs), and the modeling of a two-part self-healing system. In part II, the self-healing performance of this material system is systematically investigated. Various factors including the ratio, the total concentration and the size of the two carriers are studied as well as the healing temperature and the post heat treatment process. The best healing performance is obtained at a ratio of 1:3 of EP-capsules to AM-HGBs. It is observed that a higher concentration of larger carriers, together with a higher healing temperature, enables better healing behavior. Healing efficiency of up to 93% is obtained in these systems. In addition, post heat treatment decreases the healing efficiency due to stoichiometric mismatch of healing agents caused by leakage of amine in the HGBs at elevated temperature.

In situ synchrotron XRD analysis of the kinetics of spodumene phase transitions.

PubMed

L Moore, Radhika; Mann, Jason P; Montoya, Alejandro; Haynes, Brian S

2018-04-25

The phase transition by thermal activation of natural α-spodumene was followed by in situ synchrotron XRD in the temperature range 896 to 940 °C. We observed both β- and γ-spodumene as primary products in approximately equal proportions. The rate of the α-spodumene inversion is first order and highly sensitive to temperature (apparent activation energy ∼800 kJ mol-1). The γ-spodumene product is itself metastable, forming β-spodumene, with the total product mass fraction ratio fγ/fβ decreasing as the conversion of α-spodumene continues. We found the relationship between the product yields and the degree of conversion of α-spodumene to be the same at all temperatures in the range studied. A model incorporating first order kinetics of the α- and γ-phase inversions with invariant rate constant ratio describes the results accurately. Theoretical phonon analysis of the three phases indicates that the γ phase contains crystallographic instabilities, whilst the α and β phases do not.

Hydrotalcite-derived cobalt-aluminum mixed oxide catalysts for toluene combustion

NASA Astrophysics Data System (ADS)

Białas, Anna; Mazur, Michal; Natkański, Piotr; Dudek, Barbara; Kozak, Marek; Wach, Anna; Kuśtrowski, Piotr

2016-01-01

Hydrotalcite-like compounds (HTlcs) containing cobalt and aluminum (intended Co/Al molar ratio = 3.0) were coprecipitated at 30, 50 and 70 °C. Their crystallinity, which was confirmed by powder X-ray diffraction, increased with the precipitation temperature. Furthermore, HTlcs with various cobalt contents were prepared at 70 °C. Thermogravimetric analysis showed that HTlcs were transformed into stable oxides at 550 °C. The decrease in the crystallite size of the formed spinels with the increase in the precipitation temperature was observed. Low temperature sorption of nitrogen revealed meso-macroporous nature of the oxides with extended interparticle porosity. Aluminum segregated on the samples surface, which contained various amounts of lattice and adsorbed/electrophilic oxygen as detected by X-ray electron spectroscopy. The high ratio of lattice to adsorbed/electrophilic oxygen found for the sample with Co/Al = 3:1 caused that it turned out to be the most efficient catalyst in the total oxidation of toluene (50% conversion at 257 °C).

Optimization of the ultrasound-assisted extraction of anthocyanins and total phenolic compounds in mulberry (Morus nigra) pulp.

PubMed

Espada-Bellido, Estrella; Ferreiro-González, Marta; Carrera, Ceferino; Palma, Miguel; Barroso, Carmelo G; Barbero, Gerardo F

2017-03-15

New ultrasound-assisted extraction methods for the determination of anthocyanins and total phenolic compounds present in mulberries have been developed. Several extraction variables, including methanol composition (50-100%), temperature (10-70°C), ultrasound amplitude (30-70%), cycle (0.2-0.7s), solvent pH (3-7) and solvent-solid ratio (10:1.5-20:1.5) were optimized. A Box-Behnken design in conjunction with a response surface methodology was employed to optimize the conditions for the maximum response based on 54 different experiments. Two response variables were considered: total anthocyanins and total phenolic compounds. Extraction temperature and solvent composition were found to be the most influential parameters for anthocyanins (48°C and 76%) and phenolic compounds (64°C and 61%). The developed methods showed high reproducibility and repeatability (RSD<5%). Finally, the new methods were successfully applied to real samples in order to investigate the presence of anthocyanins and total phenolic compounds in several mulberry jams. Copyright © 2016 Elsevier Ltd. All rights reserved.

MACS, An Instrument and a Methodology for Simultaneous and Global Measurements of the Coronal Electron Temperature and the Solar Wind Velocity on the Solar Corona

NASA Technical Reports Server (NTRS)

Reginald, Nelson L.

2000-01-01

In Cram's theory for the formation of the K-coronal spectrum he observed the existence of temperature sensitive anti-nodes, which were separated by temperature insensitive nodes, at certain wave-lengths in the K-coronal spectrum. Cram also showed these properties were remarkably independent of altitude above the solar limb. In this thesis Cram's theory has been extended to incorporate the role of the solar wind in the formation of the K-corona, and we have identified both temperature and wind sensitive intensity ratios. The instrument, MACS, for Multi Aperture Coronal Spectrometer, a fiber optic based spectrograph, was designed for global and simultaneous measurements of the thermal electron temperature and the solar wind velocity in the solar corona. The first ever experiment of this nature was conducted in conjunction with the total solar eclipse of 11 August 1999 in Elazig, Turkey. Here twenty fiber optic tips were positioned in the focal plane of the telescope to observe simultaneously at many different latitudes and two different radial distances in the solar corona. The other ends were vertically stacked and placed at the primary focus of the spectrograph. By isolating the K-coronal spectrum from each fiber the temperature and the wind sensitive intensity ratios were calculated.

Heat Transfer Through Turbulent Friction Layers

NASA Technical Reports Server (NTRS)

Reichardt, H.

1943-01-01

The "general Prandtl number" Pr(exp 1) - A(sub q)/A Pr, aside from the Reynolds number determines the ratio of turbulent to molecular heat transfer, and the temperature distribution in turbulent friction layers. A(sub q) = exchange coefficient for heat; A = exchange coefficient for momentum transfer. A formula is derived from the equation defining the general Prandtl number which describes the temperature as a function of the velocity. For fully developed thermal boundary layers all questions relating to heat transfer to and from incompressible fluids can be treated in a simple manner if the ratio of the turbulent shear stress to the total stress T(sub t)/T in the layers near the wall is known, and if the A(sub q)/A can be regarded as independent of the distance from the wall. The velocity distribution across a flat smooth channel and deep into the laminar sublayer was measured for isothermal flow to establish the shear stress ratio T(sub t)/T and to extend the universal wall friction law. The values of T(sub t)/T which resulted from these measurements can be approximately represented by a linear function of the velocity in the laminar-turbulent transition zone. The effect of the temperature relationship of the material values on the flow near the wall is briefly analyzed. It was found that the velocity at the laminar boundary (in contrast to the thickness of the laminar layer) is approximately independent of the temperature distribution. The temperature gradient at the wall and the distribution of temperature and heat flow in the turbulent friction layers were calculated on the basis of the data under two equations. The derived formulas and the figures reveal the effects of the Prandtl number, the Reynolds number, the exchange quantities and the temperature relationship of the material values.

Turbulent boundary-layer velocity profiles on a nonadiabatic at Mach number 6.5

NASA Technical Reports Server (NTRS)

Keener, E. R.; Hopkins, E. J.

1972-01-01

Velocity profiles were obtained from pitot-pressure and total-temperature measurements within a turbulent boundary layer on a large sharp-edged flat plate. Momentum-thickness Reynolds number ranged from 2590 to 8860 and wall-to-adiabatic-wall temperature ratios ranged from 0.3 to 0.5. Measurements were made both with and without boundary layer trips. Five methods are evaluated for correlating the measured velocity profiles with the incompressible law-of-the-wall and the velocity defect law. The mixing-length generalization of Van Driest gives the best correlation.

Effect of design over-all compressor pressure ratio division on acceleration characteristics of three hypothetical two-spool turbojet engines

NASA Technical Reports Server (NTRS)

Filippi, Richard E; Dugan, James F , Jr

1956-01-01

The engines, each with a compressor overall total-pressure ratio of 12 and a design inner-turbine-inlet temperature of 2500 degrees R, were investigated at static sea-level conditions to determine the effect on transient performance of varying the desitn pressure ratio divisions 2-6, 3-4, and 4-3 between the outer and inner compressors. The transient considered was an acceleration from 40 to 100 percent design thrust. When the outer compressor of each engine reached design speed, the inner compressors were overspeeding, the maximum being only 1.7 over design mechanical speed. Acceleration times for the three engines were equal.

Influence of Capping Ligand and Synthesis Method on Structure and Morphology of Aqueous Phase Synthesized CuInSe2 Nanoparticles

NASA Astrophysics Data System (ADS)

Ram Kumar, J.; Ananthakumar, S.; Moorthy Babu, S.

2017-01-01

A facile route to synthesize copper indium diselenide (CuInSe2) nanoparticles in aqueous medium was developed using mercaptoacetic acid (MAA) as capping agent. Two different mole ratios (5 and 10) of MAA were used to synthesize CuInSe2 nanoparticles at room temperature, as well as hydrothermal (high temperature) method. Powder x-ray diffraction analysis reveals that the nanoparticles exhibit chalcopyrite phase and the crystallinity increases with increasing the capping ratio. Raman analysis shows a strong band at 233 cm-1 due to the combination of B2 (E) modes. Broad absorption spectra were observed for the synthesized CuInSe2 nanoparticles. The effective surface capping by MAA on the nanoparticles surface was confirmed through attenuated total reflection-Fourier transform infrared spectral analysis. The thermal stability of the synthesized samples was analyzed through thermogravimetric analysis-differential scanning calorimetry. The change in morphology of the synthesized samples was analyzed through scanning electron microscope and it shows that the samples prepared at room temperature are spherical in shape, whereas hydrothermally synthesized samples were found to have nanorod- and nanoflake-like structures. Transmission electron microscope analysis further indicates larger grains for the hydrothermally prepared samples with 10 mol ratio of MAA. Comparative analyses were made for synthesizing CuInSe2 nanoparticles by two different methods to explore the role of ligand and influence of temperature.

Improved multiple-pass Raman spectrometer

NASA Astrophysics Data System (ADS)

Kc, Utsav; Silver, Joel A.; Hovde, David C.; Varghese, Philip L.

2011-08-01

An improved Raman gain spectrometer for flame measurements of gas temperature and species concentrations is described. This instrument uses a multiple-pass optical cell to enhance the incident light intensity in the measurement volume. The Raman signal is 83 times larger than from a single pass, and the Raman signal-to-noise ratio (SNR) in room-temperature air of 153 is an improvement over that from a single-pass cell by a factor of 9.3 when the cell is operated with 100 passes and the signal is integrated over 20 laser shots. The SNR improvement with the multipass cell is even higher for flame measurements at atmospheric pressure, because detector readout noise is more significant for single-pass measurements when the gas density is lower. Raman scattering is collected and dispersed in a spectrograph with a transmission grating and recorded with a fast gated CCD array detector to help eliminate flame interferences. The instrument is used to record spontaneous Raman spectra from N2, CO2, O2, and CO in a methane--air flame. Curve fits of the recorded Raman spectra to detailed simulations of nitrogen spectra are used to determine the flame temperature from the shapes of the spectral signatures and from the ratio of the total intensities of the Stokes and anti-Stokes signals. The temperatures measured are in good agreement with radiation-corrected thermocouple measurements for a range of equivalence ratios.

Plasma/muscle ratios of sulfadimethoxine residues in channel catfish (Ictalurus punctatus).

PubMed

Walker, C C; Thune, R L; Barker, S A

1995-08-01

Channel catfish (n = 84) maintained at a water temperature of 27 degrees C were used in a feeding study to determine the plasma to muscle concentration ratios of sulfadimethoxine (SDM) and 4-N-acetylsulfadimethoxine residues. Sulfadimethoxine medicated feed was provided free choice at 42 mg SDM/kg body weight once daily for 5 days and the plasma and muscle concentrations of SDM were determined at selected withdrawal times (6, 12, 24, 48, 72, and 96 hours) following the last dose. Considerable variation in total SDM tissue concentration among fish within a sampling period was observed. For fish (n = 12) at six hours post-dose, total SDM concentrations ranged from 1.4-24.8 micrograms/mL and 0.6-12.6 micrograms/g, with mean total SDM concentrations of 9.1 micrograms/mL and 5.3 micrograms/g for plasma and muscle, respectively. However, a mean plasma:muscle concentration ratio of 1.8:1 +/- 0.3:1 was obtained over all concentrations and sampling periods. The plasma:muscle 95% t distribution interval for individual fish was 1.2:1 to 2.4:1. A correlation coefficient of 0.967 was obtained for the relationship between plasma and muscle total SDM concentration among individual fish (n = 25). Results of this study indicate that plasma total SDM concentration may be used to identify samples containing violative SDM muscle residue. No fish contained total SDM muscle residues greater than the FDA tolerance (0.1 microgram/g) by 48 hours following the final dose.

Airborne measurements of total reactive odd nitrogen (NO(y))

NASA Technical Reports Server (NTRS)

Huebler, G.; Fahey, D. W.; Ridley, B. A.; Gregory, G. L.; Fehsenfeld, F. C.

1992-01-01

Airborne total reactive odd nitrogen measurements were made during August and September 1986 over the continental United States and off the west coast over the Pacific Ocean during NASA's Global Tropospheric Experiment/Chemical Instrumentation Test and Evaluation 2 program. Measurements were made in the marine and continental boundary layer and the free troposphere up to 6.1 km altitude. NO(y) mixing ratios between 24 pptv and more than 1 ppbv were found, with median values of 101 pptv in the marine boundary layer, 298 pptv in the marine free troposphere, and 288 pptv in the continental free troposphere, respectively. The marine troposphere exhibited layered structure which was also seen in the simultaneously measured ozone mixing ratio and dew point temperature. The averaged vertical NO(y) profile over the ocean does not show a distinct gradient. The NO(y) mixing ratio over the continent decreases with increasing altitude. The latter is consistent with our understanding that the continents are the major source region for these gases.

Application of solid-acid catalyst and marine macro-algae Gracilaria verrucosa to production of fermentable sugars.

PubMed

Jeong, Gwi-Taek; Kim, Sung-Koo; Park, Don-Hee

2015-04-01

In this study, the hydrolysis of marine macro-algae Gracilaria verrucosa with a solid-acid catalyst was investigated. To optimize the hydrolysis, four reaction factors, including liquid-to-solid ratio, catalyst loading, reaction temperature, and reaction time, were investigated. In the results, the highest total reducing sugar (TRS) yield, 61 g/L (51.9%), was obtained under the following conditions: 1:7.5 solid-to-liquid ratio, 15% (w/v) catalyst loading, 140 °C reaction temperature, and 150 min reaction time. Under these conditions, 10.7 g/L of 5-HMF and 2.5 g/L of levulinic acid (LA) were generated. The application of solid-acid catalyst and marine macro-algae resources shows a very high potential for production of fermentable sugars. Copyright © 2015 Elsevier Ltd. All rights reserved.

Effect of temperature and air velocity on drying kinetics, antioxidant capacity, total phenolic content, colour, texture and microstructure of apple (var. Granny Smith) slices.

PubMed

Vega-Gálvez, Antonio; Ah-Hen, Kong; Chacana, Marcelo; Vergara, Judith; Martínez-Monzó, Javier; García-Segovia, Purificación; Lemus-Mondaca, Roberto; Di Scala, Karina

2012-05-01

The aim of this work was to study the effect of temperature and air velocity on the drying kinetics and quality attributes of apple (var. Granny Smith) slices during drying. Experiments were conducted at 40, 60 and 80°C, as well as at air velocities of 0.5, 1.0 and 1.5ms(-1). Effective moisture diffusivity increased with temperature and air velocity, reaching a value of 15.30×10(-9)m(2)s(-1) at maximum temperature and air velocity under study. The rehydration ratio changed with varying both air velocity and temperature indicating tissue damage due to processing. The colour difference, ΔE, showed the best results at 80°C. The DPPH-radical scavenging activity at 40°C and 0.5ms(-1) showed the highest antioxidant activity, closest to that of the fresh sample. Although ΔE decreased with temperature, antioxidant activity barely varied and even increased at high air velocities, revealing an antioxidant capacity of the browning products. The total phenolics decreased with temperature, but at high air velocity retardation of thermal degradation was observed. Firmness was also determined and explained using glass transition concept and microstructure analysis. Copyright © 2011 Elsevier Ltd. All rights reserved.

Trends in snowfall versus rainfall in the western United States

USGS Publications Warehouse

Knowles, N.; Dettinger, M.D.; Cayan, D.R.

2006-01-01

The water resources of the western United States depend heavily on snowpack to store part of the wintertime precipitation into the drier summer months. A well-documented shift toward earlier runoff in recent decades has been attributed to 1) more precipitation falling as rain instead of snow and 2) earlier snowmelt. The present study addresses the former, documenting a regional trend toward smaller ratios of winter-total snowfall water equivalent (SFE) to winter-total precipitation (P) during the period 1949-2004. The trends toward reduce d SFE are a response to warming across the region, with the most significant reductions occurring where winter wet-day minimum temperatures, averaged over the study period, were warmer than -5??C. Most SFE reductions were associated with winter wet-day temperature increases between 0?? and +3??C over the study period. Warmings larger than this occurred mainly at sites where the mean temperatures were cool enough that the precipitation form was less susceptible to warming trends. The trends toward reduced SFE/P ratios w ere most pronounced in March regionwide and in January near the West Coast, corresponding, to widespread warming in these months. While mean temperatures in March were sufficiently high to allow the warming, trend to produce SFE/P declines across the study region, mean January temperatures were cooler. with the result that January SFE/P impacts were restricted to the lower elevations near the West Coast. Extending the analysis back to 1920 sho ws that although the trends presented here may be partially attributable to interdecadal climate variability associated with the Pacific decadal oscillation. they also appear to result from still longer-term climate shifts.

Measurement and evaluation of the radiative properties of a thin solid fuel

NASA Technical Reports Server (NTRS)

Pettegrew, Richard; Street, Kenneth; Pitch, Nancy; Tien, James; Morrison, Phillip

2003-01-01

Accurate modeling of combustion systems requires knowledge of the radiative properties of the system. Gas phase properties are well known, but detailed knowledge of surface properties is limited. Recent work has provided spectrally resolved data for some solid fuels, but only for the unburned material at room temperature, and for limited sets of previously burned and quenched samples. Due to lack of knowledge of the spectrally resolved properties at elevated temperatures, as well as processing limitations in the modeling effort, graybody values are typically used for the fuels surface radiative properties. However, the spectrally resolved properties for the fuels at room temperature can be used to give a first-order correction for temperature effects on the graybody values. Figure 1 shows a sample of the spectrally resolved emittance/absorptance for a thin solid fuel of the type commonly used in combustion studies, from approximately 2 to 20 microns. This plot clearly shows a strong spectral dependence across the entire range. By definition, the emittance is the ratio of the emitted energy to that of a blackbody at the same temperature. Therefore, to determine a graybody emittance for this material, the spectrally resolved data must be applied to a blackbody curve. The total area under the resulting curve is ratioed to the total area under the blackbody curve to yield the answer. Due to the asymmetry of the spectrally resolved emittance and the changing shape of the blackbody curve as the temperature increases, the relative importance of the emittance value at any given wavelength will change as a function of temperature. Therefore, the graybody emittance value for a given material will change as a function of temperature even if the spectral dependence of the radiative properties remains unchanged. This is demonstrated in Figures 2 and 3, which are plots of the spectrally resolved emittance for KimWipes (shown in Figure 1) multiplied by the blackbody curves for 300 K (Figure 2) and 800 K (Figure 3). Each figure also shows the blackbody curve for that temperature. Ratioing the areas under the curve for each of these figures give a graybody emittance of 0.64 at 300 K, and 0.46 at 800 K. It is recognized that materials undergoing pyrolysis will change in composition as they heat up, and that the radiative properties of the materials may have inherent temperature dependence. Both of these effects will contribute to changes in the radiative characteristics of a given material, and are not accounted for here. However, this paper demonstrates the temperature dependence of graybody radiative properties, and provides a method for a first-order correction (for temperature) to the graybody values if the spectrally resolved properties are known.

Temperature affects the morphology and calcification of Emiliania huxleyi strains

NASA Astrophysics Data System (ADS)

Rosas-Navarro, Anaid; Langer, Gerald; Ziveri, Patrizia

2016-05-01

The global warming debate has sparked an unprecedented interest in temperature effects on coccolithophores. The calcification response to temperature changes reported in the literature, however, is ambiguous. The two main sources of this ambiguity are putatively differences in experimental setup and strain specificity. In this study we therefore compare three strains isolated in the North Pacific under identical experimental conditions. Three strains of Emiliania huxleyi type A were grown under non-limiting nutrient and light conditions, at 10, 15, 20 and 25 °C. All three strains displayed similar growth rate versus temperature relationships, with an optimum at 20-25 °C. Elemental production (particulate inorganic carbon (PIC), particulate organic carbon (POC), total particulate nitrogen (TPN)), coccolith mass, coccolith size, and width of the tube element cycle were positively correlated with temperature over the sub-optimum to optimum temperature range. The correlation between PIC production and coccolith mass/size supports the notion that coccolith mass can be used as a proxy for PIC production in sediment samples. Increasing PIC production was significantly positively correlated with the percentage of incomplete coccoliths in one strain only. Generally, coccoliths were heavier when PIC production was higher. This shows that incompleteness of coccoliths is not due to time shortage at high PIC production. Sub-optimal growth temperatures lead to an increase in the percentage of malformed coccoliths in a strain-specific fashion. Since in total only six strains have been tested thus far, it is presently difficult to say whether sub-optimal temperature is an important factor causing malformations in the field. The most important parameter in biogeochemical terms, the PIC : POC ratio, shows a minimum at optimum growth temperature in all investigated strains. This clarifies the ambiguous picture featuring in the literature, i.e. discrepancies between PIC : POC-temperature relationships reported in different studies using different strains and different experimental setups. In summary, global warming might cause a decline in coccolithophore's PIC contribution to the rain ratio, as well as improved fitness in some genotypes due to fewer coccolith malformations.

Cooling rates for glass containing lunar compositions

NASA Technical Reports Server (NTRS)

Fang, C. Y.; Yinnon, H.; Uhlmann, D. R.

1983-01-01

Cooling rates required to form glassy or partly-crystalline bodies of 14 lunar compositions have been estimated using a previously introduced, simplified model. The calculated cooling rates are found to be in good agreement with cooling rates measured for the same compositions. Measurements are also reported of the liquidus temperature and glass transition temperature for each composition. Inferred cooling rates are combined with heat flow analyses to obtain insight into the thermal histories of samples 15422, 14162, 15025, 74220, 74241, 10084, 15425, and 15427. The critical cooling rates required to form glasses of 24 lunar compositions, including the 14 compositions of the present study, are suggested to increase systematically with increasing ratio of total network modifiers/total network formers in the compositions. This reflects the importance of melt viscosity in affecting glass formation.

Measurements of hot-electron temperature in laser-irradiated plasmas

DOE PAGES

Solodov, A. A.; Yaakobi, B.; Edgell, D. H.; ...

2016-10-26

In a recently published work 1–3 we reported on measuring the total energy of hot electrons produced by the interaction of a nanosecond laser with planar CH-coated molybdenum targets, using the Mo K α emission. The temperature of the hot electrons in that work was determined by the high-energy bremsstrahlung [hard x-ray (HXR)] spectrum measured by a three-channel fluorescence-photomultiplier detector (HXRD). In the present work, we replaced the HXRD with a nine-channel image-plate (IP)–based detector (HXIP). For the same conditions (irradiance of the order of 10 14 W/cm 2; 2-ns pulses) the measured temperatures are consistently lower than those measuredmore » by the HXRD (by a factor ~1.5 to 1.7). In addition, we supplemented this measurement with three experiments that measure the hot-electron temperature using K α line-intensity ratios from high-Z target layers, independent of the HXR emission. These experiments yielded temperatures that were consistent with those measured by the HXIP. We showed that the thermal x-ray radiation must be included in the derivation of total energy in hot electrons (E hot), and that this makes E hot only weakly dependent on hot-electron temperature. For a given x-ray emission in inertial confinement fusion compression experiments, this result would lead to a higher total energy in hot electrons, but the preheat of the compressed fuel may be lower because of the reduced hot-electron range.« less

Measurements of hot-electron temperature in laser-irradiated plasmas

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

Solodov, A. A.; Yaakobi, B.; Edgell, D. H.

In a recently published work 1–3 we reported on measuring the total energy of hot electrons produced by the interaction of a nanosecond laser with planar CH-coated molybdenum targets, using the Mo K α emission. The temperature of the hot electrons in that work was determined by the high-energy bremsstrahlung [hard x-ray (HXR)] spectrum measured by a three-channel fluorescence-photomultiplier detector (HXRD). In the present work, we replaced the HXRD with a nine-channel image-plate (IP)–based detector (HXIP). For the same conditions (irradiance of the order of 10 14 W/cm 2; 2-ns pulses) the measured temperatures are consistently lower than those measuredmore » by the HXRD (by a factor ~1.5 to 1.7). In addition, we supplemented this measurement with three experiments that measure the hot-electron temperature using K α line-intensity ratios from high-Z target layers, independent of the HXR emission. These experiments yielded temperatures that were consistent with those measured by the HXIP. We showed that the thermal x-ray radiation must be included in the derivation of total energy in hot electrons (E hot), and that this makes E hot only weakly dependent on hot-electron temperature. For a given x-ray emission in inertial confinement fusion compression experiments, this result would lead to a higher total energy in hot electrons, but the preheat of the compressed fuel may be lower because of the reduced hot-electron range.« less

Positive and negative feedback loops in nutrient phytoplankton interactions related to climate dynamics factors in a shallow temperate estuary (Vistula Lagoon, southern Baltic)

NASA Astrophysics Data System (ADS)

Kruk, Marek; Kobos, Justyna; Nawrocka, Lidia; Parszuto, Katarzyna

2018-04-01

This study aims to demonstrate that factors associated with climate dynamics, such as temperature and wind, affect the ecosystem of the shallow Vistula Lagoon in the southern Baltic and cause nutrient forms phytoplankton interactions: the growth of biomass and constraints of it. This occurs through a network of direct and indirect relationships between environmental and phytoplankton factors, including interactions of positive and negative feedback loops. Path analysis supported by structural equation modeling (SEM) was used to test hypotheses regarding the impact of climate factors on algal assemblages. Increased phytoplankton biomass was affected directly by water temperature and salinity, while the wind speed effect was indirect as it resulted in increased concentrations of suspended solids (SS) in the water column. Simultaneously, the concentration of SS in the water was positively correlated with particulate organic carbon (POC), particulate nitrogen (PN), and particulate phosphorus (PP), and was negatively correlated with the total nitrogen to phosphorus (N:P) ratio. Particulate forms of C, N, and phosphorus (P), concentrations of soluble reactive phosphorus (SRP) and nitrate and nitrite nitrogen (NO3-N + NO2-N), and ratios of the total N:P and DIN:SRP, all indirectly effected Cyanobacteria C concentrations. These processes influence other phytoplankton groups (Chlorophyta, Bacillariophyceae and the picophytoplankton fraction). Increased levels of SRP associated with organic matter (POC), which stemmed from reduced DIN:SRP ratios, contributed to increased Cyanoprokaryota and picophytoplankton C concentrations, which created a positive feedback loop. However, a simultaneous reduction in the total N:P ratio could have inhibited increases in the biomass of these assemblages by limiting N, which likely formed a negative feedback loop. The study indicates that the nutrients-phytoplankton feedback loop phenomenon can intensify eutrophication in a temperate lagoon, including increases of the biomass of Cyanobacteria and picophytoplankton. However, it can also constrain this increase.

Geochemistry and origin of Puschino hot springs, Kamchaka Peninsula, Russia

NASA Astrophysics Data System (ADS)

Kalacheva, Elena

2017-04-01

Puschino hot springs are located in the valley of Kashkan River, Central Kamchatka (N54o2.938', E158o2.712') and are surface manifestations of a long-lived hydrothermal system associated with a Quaternary volcanism, off the modern volcanic front. The total natural discharge of thermal water from numerous vents is not more than 10 l/sec, vent temperatures are < 40˚ C, the total dissolved solids (TDS) < 5 g/L. The waters are near neutral (6 95 vol%). Several wells drilled in 1980th up to 600 m depth found similar waters with temperature ˜ 70˚ C and slightly higher TDS and pH. Bubbling gas is characterized by a very high 3He/4He up to 7.8Ra (Ra is the atmospheric ratio) and CO2/3He ˜ 1011, close to typical values for subduction zones. Water isotopic composition shows a positive correlation with chloride and a trend to magmatic values (up to 10 % of magmatic water). Waters have a low Ca/Sr weight ratio of ˜ 20 and the total REE concentration lower than 2 ppb. Strontium isotope ratio 87Sr/86Sr of 0.7043 ± 0.0001 is close to the ratio in the local volcanic rocks. The geological setting and a high magmatic contribution to thermal waters of Puschino may evidence that the heat and volatile source for the hydrothermal system is associated with the Olenya volcanic massive, which, according to the reconstruction by Leonov (unpublished), is an early Pleistocene (˜2Ma) postcaldera complex above a still hot and degassing intrusive body.

Optimal performance of heat engines with a finite source or sink and inequalities between means.

PubMed

Johal, Ramandeep S

2016-07-01

Given a system with a finite heat capacity and a heat reservoir, and two values of initial temperatures, T_{+} and T_{-}(

Analysis of DNA Methylation of Gracilariopsis lemaneiformis Under Temperature Stress Using the Methylation Sensitive Amplification Polymorphism (MSAP) Technique

NASA Astrophysics Data System (ADS)

Peng, Chong; Sui, Zhenghong; Zhou, Wei; Hu, Yiyi; Mi, Ping; Jiang, Minjie; Li, Xiaodong; Ruan, Xudong

2018-06-01

Gracilariopsis lemaneiformis is an economically important agarophyte, which contains high quality gel and shows a high growth rate. Wild population of G. lemaneiformis displayed resident divergence, though with a low genetic diversity as was revealed by amplified fragment length polymorphism (AFLP) and simple sequence repeat (SSR) analyses. In addition, different strains of G. lemaneiformis are diverse in morphology. The highly inconsistence between genetic background and physiological characteristics recommends strongly to the regulation at epigenetic level. In this study, the DNA methylation change in G. lemaneiformis among different generation branches and under different temperature stresses was assessed using methylation sensitive amplified polymorphism (MSAP) technique. It was shown that DNA methylation level among different generation branches was diverse. The full and total methylated DNA level was the lowest in the second generation branch and the highest in the third generation. The total methylation level was 61.11%, 60.88% and 64.12% at 15°C, 22°C and 26°C, respectively. Compared with the control group (22°C), the fully methylated and totally methylated ratios were increased in both experiment groups (15°C and 26°C). All of the cytosine methylation/demethylation transform (CMDT) was further analyzed. High temperature treatment could induce more CMDT than low temperature treatment did.

Environmental Effects on Non-oxide Ceramics

NASA Technical Reports Server (NTRS)

Jacobson, Nathan S.; Opila, Elizabeth J.

1997-01-01

Non-oxide ceramics such as silicon carbide (SiC) and silicon nitride (Si3N4) are promising materials for a wide range of high temperature applications. These include such diverse applications as components for heat engines, high temperature electronics, and re-entry shields for space vehicles. Table I lists a number of selected applications. Most of the emphasis here will be on SiC and Si3N4. Where appropriate, other non-oxide materials such as aluminum nitride (AlN) and boron nitride (BN) will be discussed. Proposed materials include both monolithic ceramics and composites. Composites are treated in more detail elsewhere in this volume, however, many of the oxidation/corrosion reactions discussed here can be extended to composites. In application these materials will be exposed to a wide variety of environments. Table I also lists reactive components of these environments.It is well-known that SiC and Si3N4 retain their strength to high temperatures. Thus these materials have been proposed for a variety of hot-gas-path components in combustion applications. These include heat exchanger tubes, combustor liners, and porous filters for coal combustion products. All combustion gases contain CO2, CO, H2, H2O, O2, and N2. The exact gas composition is dependent on the fuel to air ratio or equivalence ratio. (Equivalence ratio (EQ) is a fuel-to-air ratio, with total hydrocarbon content normalized to the amount of O2 and defined by EQ=1 for complete combustion to CO2 and H2O). Figure 1 is a plot of equilibrium gas composition vs. equivalence ratio. Note that as a general rule, all combustion atmospheres are about 10% water vapor and 10% CO2. The amounts of CO, H2, and O2 are highly dependent on equivalence ratio.

Population ecology and shell chemistry of a phytal ostracode species (Loxoconcha matagordensis) in the Chesapeake Bay watershed

USGS Publications Warehouse

Vann, C.D.; Cronin, T. M.; Dwyer, Gary S.

2004-01-01

Population ecology and shell chemistry were studied in the phytal ostracode Loxoconcha matagordensis (Swain 1955) collected from Zostera marina seagrass beds in the Chesapeake Bay to provide seasonal constraints on shell secretion time for paleothermometry. Population density and age structure were defined by two main breeding cycles that occurred between 01 to 15 June and 02 to 16 August 2001. The time interval between breeding cycles was ???2 months and total juvenile standing crop increased almost three-fold between the first and second breeding cycles. Dark brown over-wintered adults comprised the majority of the population between March and April 2001, while newly secreted translucent adults were predominant between June and September. Seasonal shell Mg/Ca and Sr/Ca ratios were positively correlated with water temperature at both sites, with the strongest correlations occurring between June and September from newly secreted shells at Dameron Marsh. Old, dark brown shells contained 10% to 23% and 1% to 6% less Mg/Ca and Sr/Ca, respectively, than new shells. Because a fossil assemblage of L. matagordensis will contain ???30% old shells (dark-brown), these results suggest that fossil Mg/Ca ratios yield an integrated late spring to summer temperature signal. Shell Mg/Ca and Sr/Ca ratios of specimens of L. matagordensis collected from living Zostera were positively correlated, suggesting that temperature may influence both elemental ratios. Mg/Ca and Sr/Ca ratios of fossil shells of the related species Loxoconcha sp. A obtained from four sediment cores were also studied and exhibited a weaker correlation between the two elemental ratios. ?? 2004 Elsevier B.V. All rights reserved.

Development of acoustically lined ejector technology for multitube jet noise suppressor nozzles by model and engine tests over a wide range of jet pressure ratios and temperatures

NASA Technical Reports Server (NTRS)

Atvars, J.; Paynter, G. C.; Walker, D. Q.; Wintermeyer, C. F.

1974-01-01

An experimental program comprising model nozzle and full-scale engine tests was undertaken to acquire parametric data for acoustically lined ejectors applied to primary jet noise suppression. Ejector lining design technology and acoustical scaling of lined ejector configurations were the major objectives. Ground static tests were run with a J-75 turbojet engine fitted with a 37-tube, area ratio 3.3 suppressor nozzle and two lengths of ejector shroud (L/D = 1 and 2). Seven ejector lining configurations were tested over the engine pressure ratio range of 1.40 to 2.40 with corresponding jet velocities between 305 and 610 M/sec. One-fourth scale model nozzles were tested over a pressure ratio range of 1.40 to 4.0 with jet total temperatures between ambient and 1088 K. Scaling of multielement nozzle ejector configurations was also studied using a single element of the nozzle array with identical ejector lengths and lining materials. Acoustic far field and near field data together with nozzle thrust performance and jet aerodynamic flow profiles are presented.

The utilization of Sambung Nyawa (Gynura procumbent [Lour]. Merr) leaves extracts as an antioxidant for coconut oil by using ethanol solvent

NASA Astrophysics Data System (ADS)

Sinaga, M. S.; Ariska, R.; Defriska, P.

2018-02-01

Sambung Nyawa (Gynura procumbent [Lour]. Merr) is commonly well-known as traditional medicine. It contains several chemical constituents such as flavonoids, saponins, tannins and steroids or triterpenoids, which are potential as an antioxidant. The aim of this study was to analyze the effect of Sambung Nyawa leaves to extract as an antioxidant and its ability to preserve the quality of coconut oil. First, flavonoids were extracted from Sambung Nyawa leaves at various leaf to the solvent ratio (w/v) and extraction temperature. The extracts which gave the highest total flavonoids content was added into the coconut oil and stored for 3 days, 6 days, 9 days, 12 days, and 15 days. Total flavonoids content of Sambung Nyawa leaves extracts were evaluated by UV-Vis spectrophotometry. Coconut oil was analyzed for its value of acid, iodine, and peroxide number. The results showed that the highest total flavonoids content of 5.18% was obtained for the leaf to solvent ratio of 1:15 (w/v) and an extraction temperature of 65 °C. The lowest acid number of 0.35%, the highest iodine number of 8.09 g I2/100 g, and the lowest peroxide number of 5.20 mg O2/100 g was obtained for the storage time of 3 days for coconut oil mixed with the Sambung Nyawa leaves extracts.

Optimization of Extraction Process for Antidiabetic and Antioxidant Activities of Kursi Wufarikun Ziyabit Using Response Surface Methodology and Quantitative Analysis of Main Components.

PubMed

Edirs, Salamet; Turak, Ablajan; Numonov, Sodik; Xin, Xuelei; Aisa, Haji Akber

2017-01-01

By using extraction yield, total polyphenolic content, antidiabetic activities (PTP-1B and α -glycosidase), and antioxidant activity (ABTS and DPPH) as indicated markers, the extraction conditions of the prescription Kursi Wufarikun Ziyabit (KWZ) were optimized by response surface methodology (RSM). Independent variables were ethanol concentration, extraction temperature, solid-to-solvent ratio, and extraction time. The result of RSM analysis showed that the four variables investigated have a significant effect ( p < 0.05) for Y 1 , Y 2 , Y 3 , Y 4 , and Y 5 with R 2 value of 0.9120, 0.9793, 0.9076, 0.9125, and 0.9709, respectively. Optimal conditions for the highest extraction yield of 39.28%, PTP-1B inhibition rate of 86.21%, α -glycosidase enzymes inhibition rate of 96.56%, and ABTS inhibition rate of 77.38% were derived at ethanol concentration 50.11%, extraction temperature 72.06°C, solid-to-solvent ratio 1 : 22.73 g/mL, and extraction time 2.93 h. On the basis of total polyphenol content of 48.44% in this optimal condition, the quantitative analysis of effective part of KWZ was characterized via UPLC method, 12 main components were identified by standard compounds, and all of them have shown good regression within the test ranges and the total content of them was 11.18%.

High-Resolution OH and CH2O Visualization in a Premixed Cavity-Anchored Ethylene-Air Flame in a M = 0.6 Flowfield

NASA Technical Reports Server (NTRS)

Geipel, Clayton M.; Rockwell, Robert D.; Chelliah, Harsha K.; Cutler, Andrew D.; Spelker, Christopher A.; Hashem, Zeid; Danehy, Paul M.

2017-01-01

OH and CH2O were imaged in a premixed, cavity-anchored, ethylene-air turbulent flame using a high resolution planar laser-induced fluorescence (PLIF) system. The electrically-heated, continuous flow facility (UVa Supersonic Combustion Facility, Configuration E) consisted of a Mach 2 nozzle, an isolator with fuel injectors, a test section with a cavity flame holder and optical access, and an extender. Standard test conditions comprised total temperature 1200 K, total pressure 300 kPa, local equivalence ratio near 0.4, and local Mach number near 0.6. OH PLIF data was also collected for a case with reduced total temperature and another with reduced equivalence ratio. OH and CH2O were excited in separate experiments with light sheets at 283.55 nm and 352.48 nm, respectively. A light sheet of approximate thickness 25 ?m illuminated the stream-wise midplane. This plane was imaged for 120 mm downstream of the backward-facing step. The intensified camera system imaged OH with magnification 1.97, a square 6.67 mm field of view, and in-plane resolution of 39 ?m. The smallest observed OH structures observed were approximately 100 ?m wide. The CH2O PLIF image signal was much weaker; the smallest observed structures were approximately 200 ?m wide. Composite fluorescence images were computed for the observed area.

Extraction kinetic modelling of total polyphenols and total anthocyanins from saffron floral bio-residues: Comparison of extraction methods.

PubMed

Da Porto, Carla; Natolino, Andrea

2018-08-30

Analysis of the extraction kinetic modelling for natural compounds is essential for industrial application. The second order rate model was applied to estimate the extraction kinetics of conventional solid-liquid extraction (CSLE), ultrasound-assisted extraction (UAE) and microwave-assisted extraction (MAE) of total polyphenols (TPC) from saffron floral bio-residues at different solid-to-liquid ratios (R S/L )(1:10, 1:20, 1:30, 1:50 g ml -1 ), ethanol 59% as solvent and 66 °C temperature. The optimum solid-to-liquid ratios for TPC kinetics were 1:20 for CLSE, 1:30 for UAE and 1:50 for MAE. The kinetics of total anthocyanins (TA) and antioxidant activity (AA) were investigated for the optimum R S/L for each method. The results showed a good prediction of the model for extraction kinetics in all experiments (R 2  > 0.99; NRMS 0.65-3.35%). The kinetic parameters were calculated and discussed. UAE, compared with the other methods, had the greater efficiency for TPC, TA and AA. Copyright © 2018 Elsevier Ltd. All rights reserved.

Partitioning Evapotranspiration in Semiarid Grassland and Shrubland Ecosystems Using Diurnal Surface Temperature Variation

NASA Technical Reports Server (NTRS)

Moran, M. Susan; Scott, Russell L.; Keefer, Timothy O.; Paige, Ginger B.; Emmerich, William E.; Cosh, Michael H.; O'Neill, Peggy E.

2007-01-01

The encroachment of woody plants in grasslands across the Western U.S. will affect soil water availability by altering the contributions of evaporation (E) and transpiration (T) to total evapotranspiration (ET). To study this phenomenon, a network of flux stations is in place to measure ET in grass- and shrub-dominated ecosystems throughout the Western U.S. A method is described and tested here to partition the daily measurements of ET into E and T based on diurnal surface temperature variations of the soil and standard energy balance theory. The difference between the mid-afternoon and pre-dawn soil surface temperature, termed Apparent Thermal Inertia (I(sub A)), was used to identify days when E was negligible, and thus, ET=T. For other days, a three-step procedure based on energy balance equations was used to estimate Qe contributions of daily E and T to total daily ET. The method was tested at Walnut Gulch Experimental Watershed in southeast Arizona based on Bowen ratio estimates of ET and continuous measurements of surface temperature with an infrared thermometer (IRT) from 2004- 2005, and a second dataset of Bowen ratio, IRT and stem-flow gage measurements in 2003. Results showed that reasonable estimates of daily T were obtained for a multi-year period with ease of operation and minimal cost. With known season-long daily T, E and ET, it is possible to determine the soil water availability associated with grass- and shrub-dominated sites and better understand the hydrologic impact of regional woody plant encroachment.

Study of commercial effective microorganism on composting and dynamics of plant essential metal micronutrients.

PubMed

Daur, Ihsanullah

2016-09-01

The present study addresses the problem of organic farmers' that needs local organic resources with their enhanced quality to effectively fertilize their agriculture crops. In accordance with the objective of the experiment that is about enhancing quality of compost, a blend of organic resources, comprising cow manure (CM), poultry manure (PM) and kitchen waste (KW) (2:1:1 ratio by volume) was composted with effective microorganisms (EM.1) (CompostEM.1) and without (Compostplain). During composting, temperature, pH, carbon, nitrogen, C/N ratio, total and diethylene triamine pentaacetic acid (DTPA)-extractable essential metal micronutrient (Fe3+, Cu2+, Zn2+, and Mn2+) contents of both the composts were recorded following the standard procedures. Low temperature range (24−24), low pH (6.7−7.2) and higher N-content (1.15−1.40) were recorded for CompostEM.1 as compared to Compostplain. Carbon degradation was also faster in CompostEM.1 than in Compostplain. Consequently, C/N ratio stabilization took 6 weeks in CompostEM.1 as compared to 18 weeks in Compostplain, leading to rapid completion of composting. Total concentration of micronutrients increased while their DTPA-extractable content decreased during the composting. Total micronutrient concentration was augmented more in Compostplain samples than in CompostEM.1. However, decrease in DTPA-extractable content was similar in both the composts. Increase in micronutrient content was attributed to decrease in organic matter weight, whereas decrease in metal micronutrients was attributed to the formation of organic matter-metal complexes during decomposition. Findings of the study indicated that effective micro-organisms enhanced composting process, however, further studies are required to evaluate its quality, especially effect on plant and soil.

40 CFR 60.4335 - How do I demonstrate compliance for NOX if I use water or steam injection?

Code of Federal Regulations, 2011 CFR

2011-07-01

... monitor and record the fuel consumption and the ratio of water or steam to fuel being fired in the turbine... continuous emission monitoring system (CEMS) consisting of a NOX monitor and a diluent gas (oxygen (O2) or... rate, temperature, and pressure, to continuously measure the total thermal energy output in British...

40 CFR 60.4335 - How do I demonstrate compliance for NOX if I use water or steam injection?

Code of Federal Regulations, 2014 CFR

2014-07-01

... monitor and record the fuel consumption and the ratio of water or steam to fuel being fired in the turbine... continuous emission monitoring system (CEMS) consisting of a NOX monitor and a diluent gas (oxygen (O2) or... rate, temperature, and pressure, to continuously measure the total thermal energy output in British...

40 CFR 60.4335 - How do I demonstrate compliance for NOX if I use water or steam injection?

Code of Federal Regulations, 2010 CFR

2010-07-01

... monitor and record the fuel consumption and the ratio of water or steam to fuel being fired in the turbine... continuous emission monitoring system (CEMS) consisting of a NOX monitor and a diluent gas (oxygen (O2) or... rate, temperature, and pressure, to continuously measure the total thermal energy output in British...

40 CFR 60.4335 - How do I demonstrate compliance for NOX if I use water or steam injection?

Code of Federal Regulations, 2012 CFR

2012-07-01

... monitor and record the fuel consumption and the ratio of water or steam to fuel being fired in the turbine... continuous emission monitoring system (CEMS) consisting of a NOX monitor and a diluent gas (oxygen (O2) or... rate, temperature, and pressure, to continuously measure the total thermal energy output in British...

40 CFR 60.4335 - How do I demonstrate compliance for NOX if I use water or steam injection?

Code of Federal Regulations, 2013 CFR

2013-07-01

... monitor and record the fuel consumption and the ratio of water or steam to fuel being fired in the turbine... continuous emission monitoring system (CEMS) consisting of a NOX monitor and a diluent gas (oxygen (O2) or... rate, temperature, and pressure, to continuously measure the total thermal energy output in British...

AN INVESTIGATION OF THE DUST CONTENT IN THE GALAXY PAIR NGC 1512/1510 FROM NEAR-INFRARED TO MILLIMETER WAVELENGTHS

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

Liu Guilin; Calzetti, Daniela; Yun, Min S.

2010-03-15

We combine new ASTE/AzTEC 1.1 mm maps of the galaxy pair NGC 1512/1510 with archival Spitzer IRAC and MIPS images covering the wavelength range 3.6-160 {mu}m from the SINGS project. The availability of the 1.1 mm map enables us to measure the long-wavelength tail of the dust emission in each galaxy, and in sub-galactic regions in NGC 1512, and to derive accurate dust masses. The two galaxies form a pair consisting of a large, high-metallicity spiral (NGC 1512) and a low-metallicity, blue compact dwarf (NGC 1510), which we use to compare similarities and contrast differences. Using the models of Drainemore » and Li, the derived total dust masses are (2.4 {+-} 0.6) x 10{sup 7} M {sub sun} and (1.7 {+-} 3.6) x 10{sup 5} M {sub sun} for NGC 1512 and NGC 1510, respectively. The derived ratio of dust mass to H I gas mass for the galaxy pair, M{sub d}/M{sub H{sub 1}}{approx}0.0034, is much lower (by at least a factor of 3) than expected, as previously found by Draine et al. In contrast, regions within NGC 1512, specifically the central region and the arms, do not show such unusually low M{sub d}/M{sub H{sub 1}} ratios; furthermore, the dust-to-gas ratio is within expectations for NGC 1510. These results suggest that a fraction of the H I included in the determination of the M{sub d}/M{sub H{sub 1}} ratio of the NGC 1512/NGC 1510 pair is not associated with the star-forming disks/regions of either galaxy. Using the dust masses derived from the models of Draine and Li as references, we perform simple two-temperature modified blackbody fits to the far-infrared/millimeter data of the two galaxies and the sub-regions of NGC 1512, in order to derive and compare the dust masses associated with warm and cool dust temperature components. As generally expected, the warm dust temperature of the low-metallicity, low-mass NGC 1510 (T{sub w} {approx} 36 K) is substantially higher than the corresponding warm temperature of the high-metallicity spiral NGC 1512 (T{sub w} {approx} 24 K). In both galaxies (albeit with a large uncertainty for NGC 1510), our fits indicate that a substantial fraction (>93%) of the total dust mass is in a cool dust component, with temperatures {approx}14-16 K for NGC 1512 and {approx}15-24 K for NGC 1510. This result is similar to what is determined for a few other nearby galaxies. In contrast, the warm dust component in the sub-galactic regions of NGC 1512 represents a much larger fraction of the total dust content, in agreement with the fact that all three regions have higher specific star formation rates than the average in the galaxy; in the center, the warm dust represents about 40% of the total, while in the arms the fractions are close to {approx}20%.« less

Temperature Histories in Ceramic-Insulated Heat-Sink Nozzle

NASA Technical Reports Server (NTRS)

Ciepluch, Carl C.

1960-01-01

Temperature histories were calculated for a composite nozzle wall by a simplified numerical integration calculation procedure. These calculations indicated that there is a unique ratio of insulation and metal heat-sink thickness that will minimize total wall thickness for a given operating condition and required running time. The optimum insulation and metal thickness will vary throughout the nozzle as a result of the variation in heat-transfer rate. The use of low chamber pressure results in a significant increase in the maximum running time of a given weight nozzle. Experimentally measured wall temperatures were lower than those calculated. This was due in part to the assumption of one-dimensional or slab heat flow in the calculation procedure.

Low-temperature creep of austenitic stainless steels

NASA Astrophysics Data System (ADS)

Reed, R. P.; Walsh, R. P.

2017-09-01

Plastic deformation under constant load (creep) in austenitic stainless steels has been measured at temperatures ranging from 4 K to room temperature. Low-temperature creep data taken from past and unreported austenitic stainless steel studies are analyzed and reviewed. Creep at cryogenic temperatures of common austenitic steels, such as AISI 304, 310 316, and nitrogen-strengthened steels, such as 304HN and 3116LN, are included. Analyses suggests that logarithmic creep (creep strain dependent on the log of test time) best describe austenitic stainless steel behavior in the secondary creep stage and that the slope of creep strain versus log time is dependent on the applied stress/yield strength ratio. The role of cold work, strain-induced martensitic transformations, and stacking fault energy on low-temperature creep behavior is discussed. The engineering significance of creep on cryogenic structures is discussed in terms of the total creep strain under constant load over their operational lifetime at allowable stress levels.

Design and cold-air test of single-stage uncooled turbine with high work output

NASA Technical Reports Server (NTRS)

Moffitt, T. P.; Szanca, E. M.; Whitney, W. J.; Behning, F. P.

1980-01-01

A solid version of a 50.8 cm single stage core turbine designed for high temperature was tested in cold air over a range of speed and pressure ratio. Design equivalent specific work was 76.84 J/g at an engine turbine tip speed of 579.1 m/sec. At design speed and pressure ratio, the total efficiency of the turbine was 88.6 percent, which is 0.6 point lower than the design value of 89.2 percent. The corresponding mass flow was 4.0 percent greater than design.

Cold-air annular-cascade investigation of aerodynamic performance of cooled turbine vanes. 2: Trailing-edge ejection, film cooling, and transpiration cooling

NASA Technical Reports Server (NTRS)

Goldman, L. J.; Mclallin, K. L.

1975-01-01

The aerodynamic performance of four different cooled vane configurations was experimentally determined in a full-annular cascade at a primary- to coolant-total-temperature ratio of 1.0. The vanes were tested over a range of coolant flow rates and pressure ratios. Overall vane efficiencies were obtained and compared, where possible, with the results obtained in a four-vane, annular-sector cascade. The vane efficiency and exit flow conditions as functions of radial position were also determined and compared with solid (uncooled) vane results.

Operating Characteristics of the Multiple Critical Venturi System and Secondary Calibration Nozzles Used for Weight-Flow Measurements in the Langley 16-Foot Transonic Tunnel

NASA Technical Reports Server (NTRS)

Berrier, B. L.; Leavitt, L. D.; Bangert, L. S.

1985-01-01

An investigation has been conducted in the Langley 16 Foot Transonic Tunnel to determine the weight flow measurement characteristics of a multiple critical Venturi system and the nozzle discharge coefficient characteristics of a series of convergent calibration nozzles. The effects on model discharge coefficient of nozzle throat area, model choke plate open area, nozzle pressure ratio, jet total temperature, and number and combination of operating Venturis were investigated. Tests were conducted at static conditions (tunnel wind off) at nozzle pressure ratios from 1.3 to 7.0.

Thermal modelling and optimisation of total useful energy rate of Joule-Brayton reheat cogeneration cycle

NASA Astrophysics Data System (ADS)

Dubey, M.; Chandra, H.; Kumar, Anil

2016-02-01

A thermal modelling for the performance evaluation of gas turbine cogeneration system with reheat is presented in this paper. The Joule-Brayton cogeneration reheat cycle is based on the total useful energy rate (TUER) has been optimised and the efficiency at the maximum TUER is determined. The variation of maximum dimensionless TUER and efficiency at maximum TUER with respect to cycle temperature ratio have also been analysed. From the results, it has been found that the dimensionless maximum TUER and the corresponding thermal efficiency decrease with the increase in power to heat ratio. The result also shows that the inclusion of reheat significantly improves the overall performance of the cycle. From the thermodynamic performance point of view, this methodology may be quite useful in the selection and comparison of combined energy production systems.

Optimization of subcritical water extraction parameters of antioxidant polyphenols from sea buckthorn (Hippophaë rhamnoides L.) seed residue.

PubMed

Gong, Ying; Zhang, Xiaofei; He, Li; Yan, Qiuli; Yuan, Fang; Gao, Yanxiang

2015-03-01

Polyphenols was extracted with subcritical water from the sea buckthorn seed residue (after oil recovery), and the extraction parameters were optimized using response surface methodology (RSM). The independent processing variables were extraction temperature, extraction time and the ratio of water to solid. The optimal extraction parameters for the extracts with highest ABTS radical scavenging activity were 120 °C, 36 min and the water to solid ratio of 20, and the maximize antioxidant capacity value was 32.42 mmol Trolox equivalent (TE)/100 g. Under the optimal conditions, the yield of total phenolics, total flavonoids and proanthocyanidins was 36.62 mg gallic acid equivalents (GAE)/g, 19.98 mg rutin equivalent (RE)/g and 10.76 mg catechin equivalents (CE)/g, respectively.

Effects of high ambient temperature on urea-nitrogen recycling in lactating dairy cows.

PubMed

Obitsu, Taketo; Kamiya, Mitsuru; Kamiya, Yuko; Tanaka, Masahito; Sugino, Toshihisa; Taniguchi, Kohzo

2011-08-01

Effects of exposure to hot environment on urea metabolism were studied in lactating Holstein cows. Four cows were fed ad libitum a total mixed ration and housed in a temperature-controlled chamber at constant moderate (18°C) or high (28°C) ambient temperatures in a cross-over design. Urea nitrogen (N) kinetics was measured by determining urea isotopomer in urine after single injection of [(15) N(2) ]urea into the jugular vein. Both dry matter intake and milk yield were decreased under high ambient temperature. Intakes of total N and digestible N were decreased under high ambient temperature but urinary urea-N excretion was increased. The ratio of urea-N production to digestible N was increased, whereas the proportion of gut urea-N entry to urea-N production tended to be decreased under high ambient temperature. Neither return to the ornithine cycle, anabolic use nor fecal excretion of urea-N recycled to the gut was affected by ambient temperature. Under high ambient temperature, renal clearance of plasma urea was not affected but the gut clearance was decreased. Increase of urea-N production and reduction of gut urea-N entry, in relative terms, were associated with increased urinary urea-N excretion of lactating dairy cows in higher thermal environments. 2011 The Authors. Animal Science Journal © 2011 Japanese Society of Animal Science.

Humic Acid Composition and Characteristics of Soil Organic Matter in Relation to the Elevation Gradient of Moso Bamboo Plantations.

PubMed

Wang, Hsueh-Ching; Chou, Chiao-Ying; Chiou, Chyi-Rong; Tian, Guanglong; Chiu, Chih-Yu

2016-01-01

Studying the influence of climatic and/or site-specific factors on soil organic matter (SOM) along an elevation gradient is important for understanding the response of SOM to global warming. We evaluated the composition of SOM and structure of humic acids along an altitudinal gradient from 600 to 1400 m in moso bamboo (Phyllostachys edulis) plantations in central Taiwan using NMR spectroscopy and photometric analysis. Total organic C and total nitrogen (N) content increased with increasing elevation. Aromaticity decreased and ΔlogK (the logarithm of the absorbance ratio of humic acids at 400 and 600 nm) increased with increasing elevation, which suggests that SOM humification decreased with increasing elevation. High temperature at low elevations seemed to enhance the decomposition (less accumulation of total organic C and N) and humification (high aromaticity and low ΔlogK). The alkyl-C/O-alkyl-C (A/O-A) ratio of humic acids increased with increasing elevation, which suggests that SOM humification increased with increasing elevation; this finding was contrary to the trend observed for ΔlogK and aromaticity. Such a discrepancy might be due to the relatively greater remaining of SOM derived from high alkyl-C broadleaf litter of previous forest at high elevations. The ratio of recalcitrant C to total organic C was low at low elevations, possibly because of enhanced decomposition of recalcitrant SOM from the previous broadleaf forest during long-term intensive cultivation and high temperature. Overall, the change in SOM pools and in the rate of humification with elevation was primarily affected by changes in climatic conditions along the elevation gradient in these bamboo plantations. However, when the composition of SOM, as assessed by NMR spectroscopy and photometric analysis was considered, site-specific factors such as residual SOM from previous forest and intensive cultivation history could also have an important effect on the humic acid composition and humification of SOM.

Humic Acid Composition and Characteristics of Soil Organic Matter in Relation to the Elevation Gradient of Moso Bamboo Plantations

PubMed Central

Wang, Hsueh-Ching; Chou, Chiao-Ying; Chiou, Chyi-Rong; Tian, Guanglong

2016-01-01

Studying the influence of climatic and/or site-specific factors on soil organic matter (SOM) along an elevation gradient is important for understanding the response of SOM to global warming. We evaluated the composition of SOM and structure of humic acids along an altitudinal gradient from 600 to 1400 m in moso bamboo (Phyllostachys edulis) plantations in central Taiwan using NMR spectroscopy and photometric analysis. Total organic C and total nitrogen (N) content increased with increasing elevation. Aromaticity decreased and ΔlogK (the logarithm of the absorbance ratio of humic acids at 400 and 600 nm) increased with increasing elevation, which suggests that SOM humification decreased with increasing elevation. High temperature at low elevations seemed to enhance the decomposition (less accumulation of total organic C and N) and humification (high aromaticity and low ΔlogK). The alkyl-C/O-alkyl-C (A/O-A) ratio of humic acids increased with increasing elevation, which suggests that SOM humification increased with increasing elevation; this finding was contrary to the trend observed for ΔlogK and aromaticity. Such a discrepancy might be due to the relatively greater remaining of SOM derived from high alkyl-C broadleaf litter of previous forest at high elevations. The ratio of recalcitrant C to total organic C was low at low elevations, possibly because of enhanced decomposition of recalcitrant SOM from the previous broadleaf forest during long-term intensive cultivation and high temperature. Overall, the change in SOM pools and in the rate of humification with elevation was primarily affected by changes in climatic conditions along the elevation gradient in these bamboo plantations. However, when the composition of SOM, as assessed by NMR spectroscopy and photometric analysis was considered, site-specific factors such as residual SOM from previous forest and intensive cultivation history could also have an important effect on the humic acid composition and humification of SOM. PMID:27583451

Steam reforming of commercial ultra-low sulphur diesel

NASA Astrophysics Data System (ADS)

Boon, Jurriaan; van Dijk, Eric; de Munck, Sander; van den Brink, Ruud

Two main routes for small-scale diesel steam reforming exist: low-temperature pre-reforming followed by well-established methane steam reforming on the one hand and direct steam reforming on the other hand. Tests with commercial catalysts and commercially obtained diesel fuels are presented for both processes. The fuels contained up to 6.5 ppmw sulphur and up to 4.5 vol.% of biomass-derived fatty acid methyl ester (FAME). Pre-reforming sulphur-free diesel at around 475 °C has been tested with a commercial nickel catalyst for 118 h without observing catalyst deactivation, at steam-to-carbon ratios as low as 2.6. Direct steam reforming at temperatures up to 800 °C has been tested with a commercial precious metal catalyst for a total of 1190 h with two catalyst batches at steam-to-carbon ratios as low as 2.5. Deactivation was neither observed with lower steam-to-carbon ratios nor for increasing sulphur concentration. The importance of good fuel evaporation and mixing for correct testing of catalysts is illustrated. Diesel containing biodiesel components resulted in poor spray quality, hence poor mixing and evaporation upstream, eventually causing decreasing catalyst performance. The feasibility of direct high temperature steam reforming of commercial low-sulphur diesel has been demonstrated.

A multi-line ammonia survey of the Galactic center region with the Tsukuba 32 m telescope. I. Observations and data

NASA Astrophysics Data System (ADS)

Arai, Hitoshi; Nagai, Makoto; Fujita, Shinji; Nakai, Naomasa; Seta, Masumichi; Yamauchi, Aya; Kaneko, Hiroyuki; Hagiwara, Kenzaburo; Mamyoda, Koh-ichi; Miyamoto, Yusuke; Horie, Masa-aki; Ishii, Shun; Koide, Yusuke; Ogino, Mitsutoshi; Maruyama, Masaki; Hirai, Katsuaki; Oshiro, Wataru; Nagai, Satoshi; Akiyama, Daiki; Konakawa, Keita; Nonogawa, Hiroaki; Salak, Dragan; Terabe, Yuki; Nihonmatsu, Yoshiki; Funahashi, Fumiyoshi

2016-10-01

We present survey data of six NH3 (J, K) = (1, 1), (2, 2), (3, 3), (4, 4), (5, 5), and (6, 6) lines, simultaneously observed with the Tsukuba 32 m telescope, in the main part of the central molecular zone of the Galaxy. The total number of on-source positions was 2655. The three lower transitions were detected with S/N > 3 at 2323 positions (93% of all the on-source positions). Among 2323, the S/N 's of (J, K) = (4, 4), (5, 5), and (6, 6) exceeded 3.0 at 1426(54%), 1150(43%), and 1359(51%) positions, respectively. Simultaneous observations of the lines enabled us to accurately derive intensity ratios with less systematic errors. Boltzmann plots indicate that there are two temperature components: cold (˜20 K) and warm (˜100 K). Typical intensity ratios of Tmb(2, 2)/Tmb(1, 1), Tmb(4, 4)/Tmb(2, 2), Tmb(5, 5)/Tmb(4, 4), and Tmb(6, 6)/Tmb(3, 3) were 0.71, 0.45, 0.65, and 0.17, respectively. These line ratios correspond to the diversity of the rotational temperature, which results from mixing of the two temperature components.

[Effect of aeration on composting of date palm residues contaminated with Fusarium oxysporum f.sp. albedinis].

PubMed

Chakroune, K; Bouakka, M; Hakkou, A

2005-01-01

Composting of date palm (Phoenix dactylifera L.) residues contaminated with Fusarium f.sp oxysporum albedinis, causal agent of the vascular wilt (Bayoud) of the date palm, has been achieved. The effect of the aeration of the piles by manual turning has been studied. The maintenance of an adequate humidity of 60%-70%, necessary to the good progress of the composting process, required the contribution of 11.4 L of water/kg of the dried residues. The evolution of the temperatures in the three piles presents the same phases. A latency phase, followed after 2-3 d of composting by a thermophilic phase, which lasts about 24 d, where the temperature remains elevated between 50 and 70 degrees C. Then a cooling phase that takes about 15 d, during which the temperatures fall to values between 25 and 35 degrees C, near room temperature. Fusarium f.sp oxysporum albedinis is eliminated completely during the thermophilic phase of composting, and increasing frequencies of turning accelerate its disappearance to a certain extent. On the other hand, pH remained steady and relatively basic oscillating between 8.2 and 8.7. Ninety percent (90%) of the the date palm residues are composed exclusively of organic matters. The total nitrogen represents only 0.4%. The contribution of manure decreases the ratio of carbon to nitrogen (C/N) from 115 to 48 in the initial mixture. After 80 d of composting and according to the frequency of return up, there is a reduction of the granulometry of the substratum, the C/N ratio (from 29% to 44%), the organic matter (from 15% to 23%), the total volume (from 25% to 35%), and of the dry weight of the swaths (from 16% to 24%). On the other hand there is an increase in total nitrogen rate (from 20% to 40%) and in the mineral matter (from 23% to 35%).

MULTI-STRAND CORONAL LOOP MODEL AND FILTER-RATIO ANALYSIS

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

Bourouaine, Sofiane; Marsch, Eckart, E-mail: bourouaine@mps.mpg.d

2010-01-10

We model a coronal loop as a bundle of seven separate strands or filaments. Each of the loop strands used in this model can independently be heated (near their left footpoints) by Alfven/ion-cyclotron waves via wave-particle interactions. The Alfven waves are assumed to penetrate the strands from their footpoints, at which we consider different wave energy inputs. As a result, the loop strands can have different heating profiles, and the differential heating can lead to a varying cross-field temperature in the total coronal loop. The simulation of Transition Region and Coronal Explorer (TRACE) observations by means of this loop modelmore » implies two uniform temperatures along the loop length, one inferred from the 171:195 filter ratio and the other from the 171:284 ratio. The reproduced flat temperature profiles are consistent with those inferred from the observed extreme-ultraviolet coronal loops. According to our model, the flat temperature profile is a consequence of the coronal loop consisting of filaments, which have different temperatures but almost similar emission measures in the cross-field direction. Furthermore, when we assume certain errors in the simulated loop emissions (e.g., due to photometric uncertainties in the TRACE filters) and use the triple-filter analysis, our simulated loop conditions become consistent with those of an isothermal plasma. This implies that the use of TRACE or EUV Imaging Telescope triple filters for observation of a warm coronal loop may not help in determining whether the cross-field isothermal assumption is satisfied or not.« less

9 Cr-- 1 Mo steel material for high temperature application

DOEpatents

Jablonski, Paul D; Alman, David; Dogan, Omer; Holcomb, Gordon; Cowen, Christopher

2012-11-27

One or more embodiments relates to a high-temperature, titanium alloyed, 9 Cr-1 Mo steel exhibiting improved creep strength and oxidation resistance at service temperatures up to 650.degree. C. The 9 Cr-1 Mo steel has a tempered martensite microstructure and is comprised of both large (0.5-3 .mu.m) primary titanium carbides and small (5-50 nm) secondary titanium carbides in a ratio of. from about 1:1.5 to about 1.5:1. The 9 Cr-1 Mo steel may be fabricated using exemplary austenizing, rapid cooling, and tempering steps without subsequent hot working requirements. The 9 Cr-1 Mo steel exhibits improvements in total mass gain, yield strength, and time-to-rupture over ASTM P91 and ASTM P92 at the temperature and time conditions examined.

Experimental evaluation of a TF30-P-3 turbofan engine in an altitude facility: Effect of steady-state temperature distortion

NASA Technical Reports Server (NTRS)

Braithwaite, W. M.

1973-01-01

The effects of circumferential distortion of the total temperature entering 25, 50, and 75 percent of the inlet circumferential annulus of a turbofan engine were determined. Complete compressor stall resulted from distortions of from 14 to 20 percent of the face averaged temperature. Increasing the temperature level in one sector resulted in that sector moving toward stall by decreasing the equivalent rotor speeds while the pressure ratio remained approximately constant. Stall originated as a rotating zone in the low-pressure compressor which resulted as a terminal stall in the high-pressure compressor. Decreasing the Reynolds number index to 0.25 from 0.5 reduced the required distortion for stall by 50 percent for the conditions investigated.

Increasing temperature reduces the coupling between available nitrogen and phosphorus in soils of Chinese grasslands

NASA Astrophysics Data System (ADS)

Geng, Yan; Baumann, Frank; Song, Chao; Zhang, Mi; Shi, Yue; Kühn, Peter; Scholten, Thomas; He, Jin-Sheng

2017-03-01

Changes in climatic conditions along geographical gradients greatly affect soil nutrient cycling processes. Yet how climate regimes such as changes in temperature influence soil nitrogen (N) and phosphorus (P) concentrations and their stoichiometry is not well understood. This study investigated the spatial pattern and variability of soil N and P availability as well as their coupling relationships at two soil layers (0-10 and 10-20 cm) along a 4000-km climate transect in two grassland biomes of China, the Inner Mongolian temperate grasslands and the Tibetan alpine grasslands. Our results found that in both grasslands, from cold to warm sites the amounts of soil total N, total P and available P all decreased. By contrast, the amount of available N was positively related to mean annual temperature in the Tibetan grasslands. Meanwhile, with increasing temperature ratio of available N to P significantly increased but the linear relationship between them was considerably reduced. Thus, increasing temperature may not only induce a stoichiometric shift but also loose the coupling between available N and P. This N-P decoupling under warmer conditions was more evident in the Tibetan alpine grasslands where P limitation might become more widespread relative to N as temperatures continue to rise.

[Study on extraction and purification process of total ginsenosides from Radix Ginseng].

PubMed

Xie, Li-Ling; Ren, Li; Lai, Xian-Sheng; Cao, Jun-Hui; Mo, Quan-Yi; Chen, Wei-Wen

2009-10-01

To optimize the technological parameters of the extraction and purification process of total ginsenosides from Radix Ginseng. With the contents of ginsenoside Rg1, ginsenoside Re and ginsenoside Rb1, the orthogonal design was adopted to optimize the extraction process. The purification process was studied by optimizing the elutive ratio of total ginsenosides as the marker. HPLC and spectrophotometer were employed for the study. The optimum conditions were as follows:Using 8 times volume of 75% ethanol extracting for 120 minutes and 2 times, the extraction temperature was 85 degrees C. AB-8 macroporous resin was selected, and the eluant was 4 BV 70% ethanol. The optimal conditions of extracting and purifying the total ginsenosides from Radix Ginseng is feasible.

Hydrogen enrichment for low-emission jet combustion

NASA Technical Reports Server (NTRS)

Clayton, R. M.

1978-01-01

Simultaneous gaseous pollutant emission indexes (g pollutant/kg fuel) for a research combustor with inlet air at 120,900 N/sq m (11.9 atm) pressure and 727 K (849 F) temperature are as low as 1.0 for NOx and CO and 0.5 for unburned HC. Emissions data are presented for hydrogen/jet fuel (JP-5) mixes and for jet fuel only for premixed equivalence ratios from lean blowout to 0.65. Minimized emissions were achieved at an equivalence ratio of 0.38 using 10-12 mass percent hydrogen in the total fuel to depress the lean blowout limit. They were not achievable with jet fuel alone because of the onset of lean blowout at an equivalence ratio too high to reduce the NOx emission sufficiently.

Breeding sex ratios in adult leatherback turtles (Dermochelys coriacea) may compensate for female-biased hatchling sex ratios.

PubMed

Stewart, Kelly R; Dutton, Peter H

2014-01-01

For vertebrates with temperature-dependent sex determination, primary (or hatchling) sex ratios are often skewed, an issue of particular relevance to concerns over effects of climate change on populations. However, the ratio of breeding males to females, or the operational sex ratio (OSR), is important to understand because it has consequences for population demographics and determines the capacity of a species to persist. The OSR also affects mating behaviors and mate choice, depending on the more abundant sex. For sea turtles, hatchling and juvenile sex ratios are generally female-biased, and with warming nesting beach temperatures, there is concern that populations may become feminized. Our purpose was to evaluate the breeding sex ratio for leatherback turtles at a nesting beach in St. Croix, USVI. In 2010, we sampled nesting females and later sampled their hatchlings as they emerged from nests. Total genomic DNA was extracted and all individuals were genotyped using 6 polymorphic microsatellite markers. We genotyped 662 hatchlings from 58 females, matching 55 females conclusively to their nests. Of the 55, 42 females mated with one male each, 9 mated with 2 males each and 4 mated with at least 3 males each, for a multiple paternity rate of 23.6%. Using GERUD1.0, we reconstructed parental genotypes, identifying 47 different males and 46 females for an estimated breeding sex ratio of 1.02 males for every female. Thus we demonstrate that there are as many actively breeding males as females in this population. Concerns about female-biased adult sex ratios may be premature, and mate choice or competition may play more of a role in sea turtle reproduction than previously thought. We recommend monitoring breeding sex ratios in the future to allow the integration of this demographic parameter in population models.

A study of the effect of helium concentration and displacement damage on the microstructure of helium ion irradiated tungsten

NASA Astrophysics Data System (ADS)

Harrison, R. W.; Greaves, G.; Hinks, J. A.; Donnelly, S. E.

2017-11-01

Transmission electron microscopy (TEM) with in-situ He ion irradiation has been used to examine the damage microstructure of W when varying the helium concentration to displacement damage ratio, irradiation temperature and total dose. Irradiations employed 15, 60 or 85 keV He ions, at temperatures between 500 and 1000 °C up to doses of ∼3.0 DPA. Once nucleated and grown to an observable size in the TEM, bubble diameter as a function of irradiation dose did not measurably increase at irradiation temperatures of 500 °C between 1.0 and 3.0 DPA; this is attributed to the low mobility of vacancies and He/vacancy complexes at these temperatures. Bubble diameter increased slightly for irradiation temperatures of 750 °C and rapidly increased when irradiated at 1000 °C. Dislocation loops were observed at irradiation temperatures of 500 and 750 °C and no loops were observed at 1000 °C. Burgers vectors of the dislocations were determined to be b = ±½<111> type only and both vacancy and interstitial loops were observed. The proportion of interstitial loops increased with He-appm/DPA ratio and this is attributed to the concomitant increase in bubble areal density, which reduces the vacancy flux for both the growth of vacancy-type loops and the annihilation of interstitial clusters.

Net energy ratio for the production of steam pretreated biomass-based pellets

DOE PAGES

Shahrukh, Hassan; Oyedun, Adetoyese Olajire; Kumar, Amit; ...

2015-06-21

In this study, a process model was developed to determine the net energy ratio (NER) for both regular and steam-pretreated pellet production from ligno-cellulosic biomass. NER is a ratio of the net energy output to the total net energy input from non-renewable energy source into the system. Scenarios were developed to measure the effect of temperature and level of steam pretreatment on the NER of both production processes. The NER for the base case at 6 kg h –1 is 1.29 and 5.0 for steam-pretreated and regular pellet production respectively. However, at the large scale NER would improve. The majormore » factor for NER is energy for steam and drying unit. The sensitivity analysis for the model shows that the optimum temperature for steam pretreatment is 200 °C with 50% pretreatment (Steam pretreating 50% feed stock, while the rest is undergoing regular pelletization). Uncertainty result for steam pretreated and regular pellet is 1.35 ± 0.09 and 4.52 ± 0.34 respectively.« less

Characteristics of a fiber-optical Fabry-Perot interferometric acoustic sensor based on an improved phase-generated carrier-demodulation mechanism

NASA Astrophysics Data System (ADS)

Mao, Xuefeng; Tian, Xiaoran; Zhou, Xinlei; Yu, Qingxu

2015-04-01

The characteristics of a fiber-optic Fabry-Perot interferometric acoustic sensor are investigated. An improved phase-generator carrier-demodulation mechanism is proposed for obtaining a high harmonic suppression ratio and stability of the demodulation results. A gold-coated polyethylene terephthalate membrane is used as the sensing diaphragm. By optimizing the parameters and the demodulation algorithm, the signal-to-noise ratio (SNR) and distortion ratio of 50.3 dB and the total harmonic distortion of 0.1% at 114 dB sound pressure level (SPL) (@ 1 kHz) are achieved, respectively. The sensor shows good temperature stability; the variation of the response is within 0.6 dB as the temperature changes from -10°C to 50°C. A sensitivity of 40 mV/Pa at 1 kHz and a frequency response range of 100 Hz to 12.5 kHz are reached, respectively. The SNR of the system is 60 dB (Re. 94 dB SPL). The sensor may be applied to photoacoustic spectrometers as a high-performance acoustic sensor.

Synthesis of adsorbent with zeolite structure from red mud and rice husk ash and its properties

NASA Astrophysics Data System (ADS)

Quyen, Dinh Thi Ngoc; Loc, Luu Cam; Ha, Huynh Ky Phuong; Nga, Dang Thi Hang; Tri, Nguyen; Van, Nguyen Thi Thuy

2017-09-01

There are many researches in the modification of red mud as adsorbent for treatment of wastewater or waste gases. Yet, most of them have to face up with a thorny problem caused by remaining alkali in red mud. In this study, the material with zeolite structure was synthesized by fusion method using red mud with the remaining alkali and rice husk ash as raw materials. It comprised alkaline fusion followed by hydrothermal treatment with step - change of synthesis temperature. The synthesized materials were characterized by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), BET and CO2 adsorption capacity. The influences on the quality of these materialswere investigated under various calcination temperatures, calcination times and the ratios of raw materials (based on SiO2/Al2O3 ratio). The optimum reaction parameters were determined. The results depicted that the sample treated at 600 °C for 2 hours with the ratio of SiO2/Al2O3 of 1.8 had the best adsorption capacity and total specific surface area compared with the others.

Destabilization of mayonnaise induced by lipid crystallization upon freezing.

PubMed

Miyagawa, Yayoi; Ogawa, Takenobu; Nakagawa, Kyuya; Adachi, Shuji

2016-01-01

The thermal and rheological history of mayonnaise during freezing and its dispersion stability after the freeze-thaw process were investigated. Mayonnaise was cooled to freeze and stored at -20 to -40 °C while monitoring the temperature; penetration tests were conducted on the mayonnaise, which was sampled at selected times during isothermal storage at -20 °C. Significant increases in the temperature and stress values due to water-phase crystallization and subsequent oil-phase crystallization were observed. The water phase crystallized during the cooling step in all the tested mayonnaise samples. The oil phases of the prepared mayonnaise (with rapeseed oil) and commercial mayonnaise crystallized during isothermal storage after 6 and 4 h, respectively, at -20 °C. The dispersion stability was evaluated from the separation ratio, which was defined as the weight ratio of separated oil after centrifuging to the total amount of oil in the commercial mayonnaise. The separation ratio rapidly increased after 4 h of freezing. This result suggests that crystallization of the oil phase is strongly related to the dispersion stability of mayonnaise.

Acceleration of high-pressure-ratio single-spool turbojet engine as determined from component performance characteristics I : effect of air bleed at compressor outlet

NASA Technical Reports Server (NTRS)

Rebeske, John J , Jr; Rohlik, Harold E

1953-01-01

An analytical investigation was made to determine from component performance characteristics the effect of air bleed at the compressor outlet on the acceleration characteristics of a typical high-pressure-ratio single-spool turbojet engine. Consideration of several operating lines on the compressor performance map with two turbine-inlet temperatures showed that for a minimum acceleration time the turbine-inlet temperature should be the maximum allowable, and the operating line on the compressor map should be as close to the surge region as possible throughout the speed range. Operation along such a line would require a continuously varying bleed area. A relatively simple two-step area bleed gives only a small increase in acceleration time over a corresponding variable-area bleed. For the modes of operation considered, over 84 percent of the total acceleration time was required to accelerate through the low-speed range ; therefore, better low-speed compressor performance (higher pressure ratios and efficiencies) would give a significant reduction in acceleration time.

Dynamical mass ejection from the merger of asymmetric binary neutron stars: Radiation-hydrodynamics study in general relativity

NASA Astrophysics Data System (ADS)

Sekiguchi, Yuichiro; Kiuchi, Kenta; Kyutoku, Koutarou; Shibata, Masaru; Taniguchi, Keisuke

2016-06-01

We perform neutrino radiation-hydrodynamics simulations for the merger of asymmetric binary neutron stars in numerical relativity. Neutron stars are modeled by soft and moderately stiff finite-temperature equations of state (EOS). We find that the properties of the dynamical ejecta such as the total mass, neutron richness profile, and specific entropy profile depend on the mass ratio of the binary systems for a given EOS in a unique manner. For a soft EOS (SFHo), the total ejecta mass depends weakly on the mass ratio, but the average of electron number per baryon (Ye ) and specific entropy (s ) of the ejecta decreases significantly with the increase of the degree of mass asymmetry. For a stiff EOS (DD2), with the increase of the mass asymmetry degree, the total ejecta mass significantly increases while the average of Ye and s moderately decreases. We find again that only for the SFHo, the total ejecta mass exceeds 0.01 M⊙ irrespective of the mass ratio chosen in this paper. The ejecta have a variety of electron number per baryon with an average approximately between Ye˜0.2 and ˜0.3 irrespective of the EOS employed, which is well suited for the production of the rapid neutron capture process heavy elements (second and third peaks), although its averaged value decreases with the increase of the degree of mass asymmetry.

Experimental investigation of supersonic combustion in a strut-cavity based combustor

NASA Astrophysics Data System (ADS)

Sathiyamoorthy, K.; Danish, Tahzeeb Hassan; Srinivas, J.; Manjunath, P.

2018-07-01

Supersonic combustion was experimentally investigated in a strut-cavity based scramjet combustor with kerosene and pilot hydrogen as fuels. Strut-cavity is the space between two tandem struts in streamwise direction. The occurrence of cavity induced pressure oscillations in the strut-cavity was confirmed through cold flow experiments. The dominant modes of pressure oscillations were strongly influenced by the cavity aspect ratio. A ventilated rear wall (VRW), which is a new passive control device, was adopted in the strut-cavity. The strut-cavity with the VRW attenuated pressure oscillations better than the 'ramp rear wall' configuration. A scramjet combustor was realized with two strut-cavities in tandem for mixing enhancement and a strut-cavity with the VRW for flame stabilization. The combustor was tested at the following inlet conditions: total pressure of 4.89 bar, total temperature of 1517 K, and Mach number of 2. Supersonic combustion was observed. Steep increase in static pressure in the region of the strut-cavity with the VRW indicated that the flame was stabilized. The combustor was operated at a wide range of equivalence ratios (0.3-0.7) without inlet interactions. The total pressure at the combustor exit plane indicated that the flow was uniform, except at the central region. The total pressure loss and combustion efficiency of the combustor were evaluated for various equivalence ratios.

Effect of Mass Flow on Stack Eductor Performance.

DTIC Science & Technology

1984-06-01

absolute viscosity, lbf-sec/ft2 - density, Ibm/ft 3 "function of" ENGLISH LETTER SYMBOLS 2 A - area, in , ft B - atmospheric pressure, in Hg c - sonic... absolute temperature ratio T* - tertiary flow to primary flow absolute temperature t ratio - secondary -o primary mass flow rate ratio W* - tertiary to...secondary to primary absolute Tp temperature ratio TiL tertiary to primary absolute -TE temperature ratio secondary to primary flow density ratio

Parametric study of flame radiation characteristics of a tubular-can combustor

NASA Technical Reports Server (NTRS)

Humenik, F. M.; Claus, R. W.; Neely, G. M.

1983-01-01

A series of combustor tests were conducted with a tubular-can combustor to study flame radiation characteristics and effects with parametric variations in combustor operating conditions. Two alternate combustor assemblies using a different fuel nozzle were compared. Spectral and total radiation detectors were positioned at three stations along the length of the combustor can. Data were obtained for a range of pressures from 0.34 to 2.07 MPa (50 to 300 psia), inlet temperatures from 533 to 700K (500 to 800 F), for Jet A (13.9 deg hydrogen) and ERBS (12.9% hydrogen) fuels, and with fuel-air ratios nominally from 0.008 to 0.021. Spectral radiation data, total radiant heat flux data, and liner temperature data are presented to illustrate the flame radiation characteristics and effects in the primary, secondary, and tertiary combustion zones.

Lignin phenols in sediments of Lake Baikal, Siberia: Application to paleoenvironmental studies

USGS Publications Warehouse

Orem, W.H.; Colman, Steven M.; Lerch, H.E.

1997-01-01

Sediments from three cores obtained from distinct depositional environments in Lake Baikal, Siberia were analyzed for organic carbon, total nitrogen and lignin phenol concentration and composition. Results were used to examine changes in paleoenvironmental conditions during climatic cycles of the late Quaternary (< 125 ka). Average organic carbon, and total nitrogen concentrations, atomic C/N ratios and organic carbon accumulation rates were significantly higher in the Holocene compared with the late Pleistocene, reflecting overall warmer temperatures and increased runoff during the Holocene. A Holocene maximum in organic carbon was observed at about 6 ka, and may represent the warmest wettest period of the Holocene. At one site (Academician Ridge) pronounced late Pleistocene maxima in organic carbon and biogenic silica were observed at about 80-85 ka, probably indicative of an interstadial period with enhanced aquatic productivity. Total sedimentary lignin phenol contents were generally lower in the late Pleistocene compared to the Holocene, but with several peaks in concentration during the late Pleistocene. These late Pleistocene peaks in total sedimentary lignin content (dated at about 80, 50 and 30 ka) directly precede or occur during peaks in sedimentary biogenic silica contents. These periods likely represent relatively warm interstadial times, with increased precipitation producing the observed increase in terrestrial runoff and aquatic productivity. Lignin phenol ratios (S/V, C/V and P/V) were used to examine changes in terrestrial vegetation type resulting from changes in paleoenvironmental conditions during the late Pleistocene. A degree of caution must be used in the interpretation of these ratios with regard to vegetation sources and paleoenvironmental conditions, because of potential compositional changes in lignin resulting from biodegradation. Nevertheless, results show that long glacial periods were characterized by terrestrial vegetation composed of a mix of non-woody angiosperm vegetation and minor gymnosperm forest. Shorter interstadial periods are defined by a change to dominant gymnosperm forest and were observed at about 80, 75, 63, 50 and 30 ka, ranging from about 2-6 kyr in duration. These interstadial periods of the late Pleistocene defined by lignin phenol ratios generally occur during longer periods of enhanced sedimentary biogenic silica content (about 10-15 ka in duration), providing corroborative evidence of these warm interstadial periods.Sediments obtained in Lake Baikal were analyzed for organic carbon, total nitrogen and lignin phenol composition and used to study changes in paleoenvironmental conditions during climatic cycles of the late Quaternary. The organic carbon, total nitrogen concentrations, atomic C/N ratios and organic carbon accumulation rates were higher in the Holocene showing overall warmer temperatures and increased runoff. Total lignin phenol contents were lower in the Pleistocene representing relatively warm interstadial times with increased precipitation, runoff and aquatic productivity. Lignin phenol was used to examine vegetation changes due to paleoenvironmental conditions and showed that long glacial periods were characterized by terrestrial vegetation.

Lifespan metabolic potential of the unicellular organisms expressed by Boltzmann constant, absolute temperature and proton mass

NASA Astrophysics Data System (ADS)

Atanasov, Atanas Todorov

2016-12-01

The unicellular organisms and phages are the first appeared fundamental living organisms on the Earth. The total metabolic energy (Els, J) of these organisms can be expressed by their lifespan metabolic potential (Als, J/kg) and body mass (M, kg): Els =Als M. In this study we found a different expression - by Boltzmann's constant (k, J/K), nucleon mass (mp+, kg) of protons (and neutrons), body mass (M, kg) of organism or mass (Ms) of biomolecules (proteins, nucleotides, polysaccharides and lipids) building organism, and the absolute temperature (T, K). The found equations are: Els= (M/mp+)kT for phages and Els=(Ms/mp+)kT for the unicellular organisms. From these equations the lifespan metabolic potential can be expressed as: Als=Els/M= (k/mp+)T for phages and Als=Els/M= (k/3.3mp+)T for unicellular organisms. The temperature-normated lifespan metabolic potential (Als/T, J/K.kg) is equals to the ratio between Boltzmann's constant and nucleon mass: Als/T=k/mp+ for phages and Als/T=k/3.3mp+ for unicellular organisms. The numerical value of the k/mp+ ratio is equals to 8.254×103 J/K.kg, and the numerical value of k/3.3mp+ ratio is equal to 2.497×103 J/K.kg. These values of temperature-normated lifespan metabolic potential could be considered fundamental for the unicellular organisms.

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

Senesi, Roberto; Flammini, Davide; Kolesnikov, Alexander I.

The OH stretching vibrational spectrum of water was measured in a wide range of temperatures across the triple point, 269 K < T < 296 K, using Inelastic Neutron Scattering (INS). The hydrogen projected density of states and the proton mean kinetic energy, _OH, were determined for the first time within the framework of a harmonic description of the proton dynamics. We found that in the liquid the value of _OH is nearly constant as a function of T, indicating that quantum effects on the OH stretching frequency are weakly dependent on temperature. In the case of ice, ab initiomore » electronic structure calculations, using non-local van der Waals functionals, provided _OH values in agreement with INS experiments. We also found that the ratio of the stretching (_OH) to the total (_exp) kinetic energy, obtained from the present measurements, increases in going from ice, where hydrogen bonding is the strongest, to the liquid at ambient conditions and then to the vapour phase, where hydrogen bonding is the weakest. The same ratio was also derived from the combination of previous deep inelastic neutron scattering data, which does not rely upon the harmonic approximation, and the present measurements. We found that the ratio of stretching to the total kinetic energy shows a minimum in the metastable liquid phase. This finding suggests that the strength of intermolecular interactions increases in the supercooled phase, with respect to that in ice, contrary to the accepted view that supercooled water exhibits weaker hydrogen bonding than ice.« less

Turbulent Flow Field Measurements of Separate Flow Round and Chevron Nozzles with Pylon Interaction Using Particle Image Velocimetry

NASA Technical Reports Server (NTRS)

Doty, Michael J.; Henerson, Brenda S.; Kinzie, Kevin W.

2004-01-01

Particle Image Velocimetry (PIV) measurements for six separate flow bypass ratio five nozzle configurations have recently been obtained in the NASA Langley Jet Noise Laboratory. The six configurations include a baseline configuration with round core and fan nozzles, an eight-chevron core nozzle at two different clocking positions, and repeats of these configurations with a pylon included. One run condition representative of takeoff was investigated for all cases with the core nozzle pressure ratio set to 1.56 and the total temperature to 828 K. The fan nozzle pressure ratio was set to 1.75 with a total temperature of 350 K, and the freestream Mach number was M = 0.28. The unsteady flow field measurements provided by PIV complement recent computational, acoustic, and mean flow field studies performed at NASA Langley for the same nozzle configurations and run condition. The PIV baseline configuration measurements show good agreement with mean flow field data as well as existing PIV data acquired at NASA Glenn. Nonetheless, the baseline configuration turbulence profile indicates an asymmetric flow field, despite careful attention to concentricity. The presence of the pylon increases the upper shear layer turbulence levels while simultaneously decreasing the turbulence levels in the lower shear layer. In addition, a slightly shorter potential core length is observed with the addition of the pylon. Finally, comparisons of computational results with PIV measurements are favorable for mean flow, slightly over-predicted for Reynolds shear stress, and underpredicted for Reynolds normal stress components.

Radial Variations in the Io Plasma Torus during the Cassini Era

NASA Technical Reports Server (NTRS)

Delamere, P. A.; Bagenal, F.; Steffl, A.

2005-01-01

A radial scan through the midnight sector of the Io plasma torus was made by the Cassini Ultraviolet Imaging Spectrograph on 14 January 2001, shortly after closest approach to Jupiter. From these data, Steffl et al. (2004a) derived electron temperature, plasma composition (ion mixing ratios), and electron column density as a function of radius from L = 6 to 0 as well as the total luminosity. We have advanced our homogeneous model of torus physical chemistry (Delamere and Bagenal, 2003) to include latitudinal and radial variations in a manner similar to the two-dimensional model by Schreier et al. (1998). The model variables include: (1) neutral source rate, (2) radial transport coefficient, (3) the hot electron fraction, (4) hot electron temperature, and (5) the neutral O/S ratio. The radial variation of parameters 1-4 are described by simple power laws, making a total of nine parameters. We have explored the sensitivity of the model results to variations in these parameters and compared the best fit with previous Voyager era models (schreier et al., 1998), galileo data (Crary et al., 1998), and Cassini observations (steffl et al., 2004a). We find that radial variations during the Cassini era are consistent with a neutral source rate of 700-1200 kg/s, an integrated transport time from L = 6 to 9 of 100-200 days, and that the core electron temperature is largely determined by a spatially and temporally varying superthermal electron population.

The Radioactivity Characteristics of the NPP Charcoal Sample Contaminated by Carbon-14 - 13531

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

Kim, Hee Reyoung

2013-07-01

The radioactivity of {sup 14}C-contaminated charcoal sample was analyzed by using a high temperature oxidation and liquid scintillation counting method. The radioactivity of the sample was monotonically increased according to the increase of the combustion time at each temperature where the experimental uncertainty was calculated in the 95 % confidence level. It showed that the {sup 14}C radioactivity was not completely extracted from the sample by simply increasing the combustion time unless the combustion temperature was high enough. The higher the combustion temperature was, the higher the recovery during the first 30 minutes was. The first 30 minute recoveries weremore » 100 % at a temperature equal to or greater than 450 deg. C. The ratios of the recovery during the first 30 minutes to the total recovery during whole duration were more than 90 % at each experiment temperature. It was understood that the temperature was a critical factor for the complete removal of the {sup 14}C from the waste sample. (authors)« less

Heat transfer rate and film cooling effectiveness measurements in a transient cascade

NASA Astrophysics Data System (ADS)

Schultz, D. L.; Oldfield, M. L. G.; Jones, T. V.

1980-09-01

A transient cascade useful for heat transfer rate measurements is briefly described. The facility employs a free piston which compresses the test gas to temperatures around 450 K and pressures of about 3.5 to 7.5 Atm. The model is initially at room temperature and it is necessary to attain the correct gas to wall temperature ratio. The exit Mach number is set by the inlet total pressure and the pressure in the exit dump tank. Thin film heat transfer gauges are used for the measurement of heat transfer rate, deposited on machineable glass ceramic blades. The inherently fast response of these transducers makes them useful for the investigation of boundary layer transition on blade surfaces and some typical results are included.

Thermodynamic analyses of a biomass-coal co-gasification power generation system.

PubMed

Yan, Linbo; Yue, Guangxi; He, Boshu

2016-04-01

A novel chemical looping power generation system is presented based on the biomass-coal co-gasification with steam. The effects of different key operation parameters including biomass mass fraction (Rb), steam to carbon mole ratio (Rsc), gasification temperature (Tg) and iron to fuel mole ratio (Rif) on the system performances like energy efficiency (ηe), total energy efficiency (ηte), exergy efficiency (ηex), total exergy efficiency (ηtex) and carbon capture rate (ηcc) are analyzed. A benchmark condition is set, under which ηte, ηtex and ηcc are found to be 39.9%, 37.6% and 96.0%, respectively. Furthermore, detailed energy Sankey diagram and exergy Grassmann diagram are drawn for the entire system operating under the benchmark condition. The energy and exergy efficiencies of the units composing the system are also predicted. Copyright © 2016 Elsevier Ltd. All rights reserved.

The relationship of normal body temperature, end-expired breath temperature, and BAC/BrAC ratio in 98 physically fit human test subjects.

PubMed

Cowan, J Mack; Burris, James M; Hughes, James R; Cunningham, Margaret P

2010-06-01

The relationship between normal body temperature, end-expired breath temperature, and blood alcohol concentration (BAC)/breath alcohol concentration (BrAC) ratio was studied in 98 subjects (84 men, 14 women). Subjects consumed alcohol sufficient to produce a BrAC of at least 0.06 g/210 L 45-75 min after drinking. Breath samples were analyzed using an Intoxilyzer 8000 specially equipped to measure breath temperature. Venous blood samples and body temperatures were then taken. The mean body temperature of the men (36.6 degrees C) was lower than the women (37.0 degrees C); however, their mean breath temperatures were virtually identical (men: 34.5 degrees C; women: 34.6 degrees C). The BAC exceeded the BrAC for every subject. BAC/BrAC ratios were calculated from the BAC and BrAC analytical results. There was no difference in the BAC/BrAC ratios for men (1:2379) and women (1:2385). The correlation between BAC and BrAC was high (r = 0.938, p < 0.0001), whereas the correlations between body temperature and end-expired breath temperature, body temperature and BAC/BrAC ratio, and breath temperature and BAC/BrAC ratio were much lower. Neither normal body temperature nor end-expired breath temperature was strongly associated with BAC/BrAC ratio.

Geometrical evidence for dark matter: X-ray constraints on the mass of the elliptical galaxy NGC 720

NASA Astrophysics Data System (ADS)

Buote, David A.; Canizares, Claude R.

1994-05-01

We describe (1) a new test for dark matter and alternate theories of gravitation based on the relative geometries of the X-ray and optical surface brightness distributions and an assumed form for the potential, of the optical light, (2) a technique to measure the shapes of the total gravitating matter and dark matter of an ellipsoidal system which is insensitive to the precise value of the temperature of the gas and to modest temperature gradients, and (3) a new method to determine the ratio of dark mass to stellar mass that is dependent on the functional forms for the visible star, gas and dark matter distributions, but independent of the distance to the galaxy or the gas temperature. We apply these techniques to X-ray data from the ROSAT Position Sensitive Proportional Counter (PSPC) of the optically flattened elliptical galaxy NGC 720; the optical isophotes have ellipticity epsilon approximately 0.40 extending out to approximately 120 sec. The X-ray isophotes are significantly elongated, epsilon = 0.20-0.30 for semimajor axis a approximately 100 sec. The major axes of the optical and X-ray isophotes are misaligned by approximately 30 deg +/- 15 deg. Spectral analysis of the X-ray data reveals no evidence of temperature gradients or anisotropies and demonstrates that a single-temperature plasma (T approximately 0.6 keV) having subsolar heavy element abundances and a two-temperature model having solar abundances describe the spectrum equally well. Considering only the relative geometries of the X-ray and optical surface brightness distributions and an assumed functional form for the potential of the optical light, we conclude that matter distributed like the optical light cannot produce the observed ellipticities of the X-ray isophotes, independent of the gas pressure, the gas temperature, and the value of the stellar mass; this comparison assumes a state of quasi-hydrostatic equilibrium so that the three-dimensional surfaces of the gas emissivity trace the three-dimensional isopotential surfaces -- we discuss the viability of this assumption for NGC 720. Milgrom's Modification of Newtonian Dynamics (MOND) cannot dispel this manifestation of dark matter. Hence, geometrical considerations require, without mention of pressure or temperature, the presence of an extended, massive dark matter halo in NGC 720. Employing essentially the technique of Buote & Canizares (1992; Buote 1992) we use the shape of the X-ray surface brightness to constrain the shape of the total gravitating matter. The total matter is modeled as either an oblate or prolate spheriod of constant shape and orientation having either a Ferrers (rho approximately r-n) or Hernquist density. Assuming the X-ray gas is in hydrostatic equilibrium, we construct a model X-ray gas distribution for various temperature profiles. We determine the ellipticity of the total gravitating matter to be epsilon approximately 0.50-0.70. Using the single-temperature model we estimate a total mass approximately (0.41-1.4) x 1012 h80 solar mass interior to the ellipsoid of semimajor axis 43.6 h80 kpc. Ferrers densities as steep as r-3 do not fit the data, but the r-2 and Hernquist models yield excellent fits. We estimate the mass distributions of the stars and the gas and fit the dark matter directly. For a given gas equation of state and functional forms for the visible stars, gas, and dark matter, these models yield a distance-independent and temperature-independent measurement of the ratio of dark mass to stellar mass MDM/Mstars. We estimate a minimum MDM/Mstars greater than or equal to 4 which corresponds to a total mass slightly greater than that derived from the single-temperature models for distance D = 20h80 Mpc.

Geometrical evidence for dark matter: X-ray constraints on the mass of the elliptical galaxy NGC 720

NASA Technical Reports Server (NTRS)

Buote, David A.; Canizares, Claude R.

1994-01-01

We describe (1) a new test for dark matter and alternate theories of gravitation based on the relative geometries of the X-ray and optical surface brightness distributions and an assumed form for the potential, of the optical light, (2) a technique to measure the shapes of the total gravitating matter and dark matter of an ellipsoidal system which is insensitive to the precise value of the temperature of the gas and to modest temperature gradients, and (3) a new method to determine the ratio of dark mass to stellar mass that is dependent on the functional forms for the visible star, gas and dark matter distributions, but independent of the distance to the galaxy or the gas temperature. We apply these techniques to X-ray data from the ROSAT Position Sensitive Proportional Counter (PSPC) of the optically flattened elliptical galaxy NGC 720; the optical isophotes have ellipticity epsilon approximately 0.40 extending out to approximately 120 sec. The X-ray isophotes are significantly elongated, epsilon = 0.20-0.30 for semimajor axis a approximately 100 sec. The major axes of the optical and X-ray isophotes are misaligned by approximately 30 deg +/- 15 deg. Spectral analysis of the X-ray data reveals no evidence of temperature gradients or anisotropies and demonstrates that a single-temperature plasma (T approximately 0.6 keV) having subsolar heavy element abundances and a two-temperature model having solar abundances describe the spectrum equally well. Considering only the relative geometries of the X-ray and optical surface brightness distributions and an assumed functional form for the potential of the optical light, we conclude that matter distributed like the optical light cannot produce the observed ellipticities of the X-ray isophotes, independent of the gas pressure, the gas temperature, and the value of the stellar mass; this comparison assumes a state of quasi-hydrostatic equilibrium so that the three-dimensional surfaces of the gas emissivity trace the three-dimensional isopotential surfaces -- we discuss the viability of this assumption for NGC 720. Milgrom's Modification of Newtonian Dynamics (MOND) cannot dispel this manifestation of dark matter. Hence, geometrical considerations require, without mention of pressure or temperature, the presence of an extended, massive dark matter halo in NGC 720. Employing essentially the technique of Buote & Canizares (1992; Buote 1992) we use the shape of the X-ray surface brightness to constrain the shape of the total gravitating matter. The total matter is modeled as either an oblate or prolate spheriod of constant shape and orientation having either a Ferrers (rho approximately r(exp -n)) or Hernquist density. Assuming the X-ray gas is in hydrostatic equilibrium, we construct a model X-ray gas distribution for various temperature profiles. We determine the ellipticity of the total gravitating matter to be epsilon approximately 0.50-0.70. Using the single-temperature model we estimate a total mass approximately (0.41-1.4) x 10(exp 12) h(sub 80) solar mass interior to the ellipsoid of semimajor axis 43.6 h(sub 80) kpc. Ferrers densities as steep as r(exp -3) do not fit the data, but the r(exp -2) and Hernquist models yield excellent fits. We estimate the mass distributions of the stars and the gas and fit the dark matter directly. For a given gas equation of state and functional forms for the visible stars, gas, and dark matter, these models yield a distance-independent and temperature-independent measurement of the ratio of dark mass to stellar mass M(sub DM)/M(sub stars). We estimate a minimum M(sub DM)/M(sub stars) greater than or equal to 4 which corresponds to a total mass slightly greater than that derived from the single-temperature models for distance D = 20h(sub 80) Mpc.

Application of self-preservation in the diurnal evolution of the surface energy budget to determine daily evaporation

NASA Technical Reports Server (NTRS)

Brutsaert, Wilfried; Sugita, Michiaki

1992-01-01

Evaporation from natural land surfaces often exhibits a strong variation during the course of a day, mostly in response to the daily variation of radiative energy input at the surface. This makes it difficult to derive the total daily evaporation, when only one or a few instantaneous estimates of evaporation are available. It is often possible to resolve this difficulty by assuming self-preservation in the diurnal evolution of the surface energy budget. Thus if the relative partition of total incoming energy flux among the different components remains the same, the ratio of latent heat flux and any other flux component can be taken as constant through the day. This concept of constant flux ratios is tested by means of data obtained during the First ISLSCP Field Experiment; the instantaneous evaporation values were calculated by means of the atmospheric boundary layer bulk similarity approach with radiosonde profiles and radiative surface temperatures. Good results were obtained for evaporative flux ratios with available energy flux, with net radiation, and with incoming shortwave radiation.

Solar energy potential in the United Arab Emirates

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

Khalil, A.; Alnajjar, A.

1995-12-31

In the present study, the global, direct and diffuse components of solar radiation as well as temperature, relative humidity and wind speed have been continuously monitored and analyzed on hourly, daily and monthly basis. Experimental data is compared to the predictions of different theoretical models as functions of declination and hour angles. Correlations are obtained describing the variation of hourly, daily and monthly averages of total and diffuse solar radiation using polynomial expressions. Empirical correlations describing the dependence of the daily average diffuse to total radiation ratio on the clearness index are also obtained. Data of daily diffuse to totalmore » radiation ratio is compared to correlations obtained by other investigators. The comparison shows a reasonable agreement with some scatter due to the seasonal dependence of the correlation. Comparison of calculations with experimental measurements under clear sky conditions show excellent agreement with a maximum error of 8%. The measured ratio of hourly to daily insolation is in excellent agreement with the model of Hottel which is expressed as a function of the clearness index, hour and the sunset hour angles.« less

Influence of synthesis and sintering parameters on the characteristics of carbonate apatite.

PubMed

Landi, Elena; Tampieri, Anna; Celotti, Giancarlo; Vichi, Lucia; Sandri, Monica

2004-05-01

A new method to synthesise carbonate-substituted hydroxyapatite (CHA) powder has been set up introducing a CO(2) flux, as a source of carbonate, in the HA synthesis process based on the neutralisation reaction. The reactants are abundant and inexpensive. The yield is good compared to other CHA powder synthesis. The reaction may be performed at low temperature and without pH control and does not produce any by-products. The influence of the synthesis parameters (temperature, H(3)PO(4) solution dropping rate, i.e. reaction time, CO(2) flux, ageing time) has been tested to optimise the process conditions in order to obtain the highest carbonation degree and favour the B-type CHA precipitation with respect to A-type one. The prepared powder (5.8wt% of total carbonate with an A/B ratio of 0.78) was thermally treated at various temperatures in the range 500-1400 degrees C in different atmospheres (air, wet and dry carbon dioxide). The thermal treatments were performed with a double aim, to eliminate selectively the carbonate groups in A-position maintaining the B-type substitution, and to evaluate the thermal stability of the CHA and the total loss of carbonate as a function of temperature. The thermal treatment at 900 degrees C in wet CO(2) gave the best result in terms of a high carbonate residue and a low A/B ratio. We also investigate the use of different techniques (inductively coupled plasma, TGA, Fourier transformed infrared spectroscopy, X-ray diffraction) for characterising CHA and calculating sensitivity and accuracy in the quantification of carbonate ions for each molecular site.

Selective vibrational pumping of molecular hydrogen via gas phase atomic recombination.

PubMed

Esposito, Fabrizio; Capitelli, Mario

2009-12-31

Formation of rovibrational excited molecular hydrogen from atomic recombination has been computationally studied using three body dynamics and orbiting resonance theory. Each of the two methods in the frame of classical mechanics, that has been used for all of the calculations, appear complementary rather than complete, with similar values in the low temperature region, and predominance of three body dynamics for temperatures higher than about 1000 K. The sum of the two contributions appears in fairly good agreement with available data from the literature. Dependence of total recombination on the temperature over pressure ratio is stressed. Detailed recombination toward rovibrational states is presented, with large evidence of importance of rotation in final products. Comparison with gas-surface recombination implying only physiadsorbed molecules shows approximate similarities at T = 5000 K, being on the contrary different at lower temperature.

Intra- and inter-unit variation in fly ash petrography and mercury adsorption: Examples from a western Kentucky power station

USGS Publications Warehouse

Hower, J.C.; Finkelman, R.B.; Rathbone, R.F.; Goodman, J.

2000-01-01

Fly ash was collected from eight mechanical and 10 baghouse hoppers at each of the twin 150-MW wall-fired units in a western Kentucky power station. The fuel burned at that time was a blend of many low-sulfur, high-volatile bituminous Central Appalachian coals. The baghouse ash showed less variation between units than the mechanical hoppers. The mechanical fly ash, coarser than the baghouse ash, showed significant differences in the amount of total carbon and in the ratio of isotropic coke to both total carbon and total coke - the latter excluding inertinite and other unburned, uncoked coal. There was no significant variation in proportions of inorganic fly ash constituents. The inter-unit differences in the amount and forms of mechanical fly ash carbon appear to be related to differences in pulverizer efficiency, leading to greater amounts of coarse coal, therefore unburned carbon, in one of the units. Mercury capture is a function of both the total carbon content and the gas temperature at the point of fly ash separation, mercury content increasing with an increase in carbon for a specific collection system. Mercury adsorption on fly ash carbon increases at lower flue-gas temperatures. Baghouse fly ash, collected at a lower temperature than the higher-carbon mechanically separated fly ash, contains a significantly greater amount of Hg.

Low-pressure chemical vapor deposition of low in situ phosphorus doped silicon thin films

NASA Astrophysics Data System (ADS)

Sarret, M.; Liba, A.; Bonnaud, O.

1991-09-01

In situ low phosphorus doped silicon films are deposited onto glass substrates by low-pressure chemical vapor deposition method. The deposition parameters, temperature, total pressure, and pure silane gas flow are, respectively, fixed at 550 °C, 0.08 Torr, and 50 sccm. The varying deposition parameter is phosphine/silane mole ratio; when this ratio varies from 2×10-6 to 4×10-4, the phosphorus concentration and the resistivity after annealing, respectively, vary from 2×1018 to 3×1020 atoms cm-3 and from 1.5 Ω cm to 2.5×10-3 Ω cm.

Diffusivity of nitrous oxide in N-methyldiethanolamine + diethanolamine + water

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

Rinker, E.B.; Russell, J.W.; Tamimi, A.

1995-05-01

The tertiary amine N-methyldiethanolamine and the secondary amine diethanolamine are commonly used in the gas-treating industry as chemical solvents for the removal of acid gases such as CO{sub 2} and H{sub 2}S. The diffusion coefficients for nitrous oxide in aqueous solutions consisting of N-methyldiethanolamine (MDEA) and diethanolamine (DEA) were measured over the temperature range 293--353 K for a total amine concentration of 50 mass % and for the mass ratio of DEA to MDEA varying from 0.0441 to 0.588. The experimental diffusion coefficients were found to be relatively insensitive to the mass ratio of amines.

Photo Degradation of Methyl Orange by Persulfate Activated with Zero Valent Iron

NASA Astrophysics Data System (ADS)

Munkoeva, V. A.; Sizykh, M. R.; Batoeva, A. A.

2017-11-01

The oxidative degradation of Methyl Orange (MO) subjected to direct photolysis (Solar) and various oxidative systems was studied. The comparative experiments have shown that MO conversion and mineralization increases in the following order: Solar ∼ Solar/Fe0 ∼ Solar/S2O82- < S2O82-/Fe0 < Solar/S2O82-/Fe0. The influence of the main factors (duration of exposure, the ratio of initial concentrations of MO:S2O82-:Fe0, pH and temperature of the reaction medium) on the degree of MO conversion and mineralization was studied. The optimal pH and temperature of the reaction medium were 5.8 and 25°C, respectively. The rate of MO decomposition and mineralization increased proportionally to the initial concentration of the oxidant at the molar ratios [S2O82-] :[MO] ≤ 12. Judging by the nature of the kinetic curves, a further increase of this ratio is impractical. However, an increase in the oxidant concentration had a positive effect on the degrees of conversion and mineralization of total organic carbon (TOC). Thus, at the ratios of 12:1 and 48:1, the conversion efficiency of TOC was 23 and 60 %, respectively. The optimal concentration of Fe0 was 100 mg/l.

The Scaling of Broadband Shock-Associated Noise with Increasing Temperature

NASA Technical Reports Server (NTRS)

Miller, Steven A.

2012-01-01

A physical explanation for the saturation of broadband shock-associated noise (BBSAN) intensity with increasing jet stagnation temperature has eluded investigators. An explanation is proposed for this phenomenon with the use of an acoustic analogy. For this purpose the acoustic analogy of Morris and Miller is examined. To isolate the relevant physics, the scaling of BBSAN at the peak intensity level at the sideline ( = 90 degrees) observer location is examined. Scaling terms are isolated from the acoustic analogy and the result is compared using a convergent nozzle with the experiments of Bridges and Brown and using a convergent-divergent nozzle with the experiments of Kuo, McLaughlin, and Morris at four nozzle pressure ratios in increments of total temperature ratios from one to four. The equivalent source within the framework of the acoustic analogy for BBSAN is based on local field quantities at shock wave shear layer interactions. The equivalent source combined with accurate calculations of the propagation of sound through the jet shear layer, using an adjoint vector Green s function solver of the linearized Euler equations, allows for predictions that retain the scaling with respect to stagnation pressure and allows for the accurate saturation of BBSAN with increasing stagnation temperature. This is a minor change to the source model relative to the previously developed models. The full development of the scaling term is shown. The sources and vector Green s function solver are informed by steady Reynolds-Averaged Navier-Stokes solutions. These solutions are examined as a function of stagnation temperature at the first shock wave shear layer interaction. It is discovered that saturation of BBSAN with increasing jet stagnation temperature occurs due to a balance between the amplification of the sound propagation through the shear layer and the source term scaling.A physical explanation for the saturation of broadband shock-associated noise (BBSAN) intensity with increasing jet stagnation temperature has eluded investigators. An explanation is proposed for this phenomenon with the use of an acoustic analogy. For this purpose the acoustic analogy of Morris and Miller is examined. To isolate the relevant physics, the scaling of BBSAN at the peak intensity level at the sideline psi = 90 degrees) observer location is examined. Scaling terms are isolated from the acoustic analogy and the result is compared using a convergent nozzle with the experiments of Bridges and Brown and using a convergent-divergent nozzle with the experiments of Kuo, McLaughlin, and Morris at four nozzle pressure ratios in increments of total temperature ratios from one to four. The equivalent source within the framework of the acoustic analogy for BBSAN is based on local field quantities at shock wave shear layer interactions. The equivalent source combined with accurate calculations of the propagation of sound through the jet shear layer, using an adjoint vector Green s function solver of the linearized Euler equations, allows for predictions that retain the scaling with respect to stagnation pressure and allows for the accurate saturation of BBSAN with increasing stagnation temperature. This is a minor change to the source model relative to the previously developed models. The full development of the scaling term is shown. The sources and vector Green s function solver are informed by steady Reynolds-Averaged Navier-Stokes solutions. These solutions are examined as a function of stagnation temperature at the first shock wave shear layer interaction. It is discovered that saturation of BBSAN with increasing jet stagnation temperature occurs due to a balance between the amplification of the sound propagation through the shear layer and the source term scaling.

Real-gas effects 1: Simulation of ideal gas flow by cryogenic nitrogen and other selected gases

NASA Technical Reports Server (NTRS)

Hall, R. M.

1980-01-01

The thermodynamic properties of nitrogen gas do not thermodynamically approximate an ideal, diatomic gas at cryogenic temperatures. Choice of a suitable equation of state to model its behavior is discussed and the equation of Beattie and Bridgeman is selected as best meeting the needs for cryogenic wind tunnel use. The real gas behavior of nitrogen gas is compared to an ideal, diatomic gas for the following flow processes: isentropic expansion; normal shocks; boundary layers; and shock wave boundary layer interactions. The only differences in predicted pressure ratio between nitrogen and an ideal gas that may limit the minimum operating temperatures of transonic cryogenic wind tunnels seem to occur at total pressures approaching 9atmospheres and total temperatures 10 K below the corresponding saturation temperature, where the differences approach 1 percent for both isentropic expansions and normal shocks. Several alternative cryogenic test gases - air, helium, and hydrogen - are also analyzed. Differences in air from an ideal, diatomic gas are similar in magnitude to those of nitrogen. Differences for helium and hydrogen are over an order of magnitude greater than those for nitrogen or air. Helium and hydrogen do not approximate the compressible flow of an ideal, diatomic gas.

Physical-chemical characterization of the textile dye Azo Ab52 degradation by corona plasma

NASA Astrophysics Data System (ADS)

Gómez, A.; Torres-Arenas, A. J.; Vergara-Sánchez, J.; Torres, C.; Reyes, P. G.; Martínez, H.; Saldarriaga-Noreña, Hugo

2017-10-01

This work characterizes the degradation of the textile dye azo Acid Black 52 by measuring several physical and chemical parameters. A corona plasma was created at atmospheric pressure and applied on the liquid-air interface of water samples containing the dye. 1.0 mM of ferrous sulfate (FeSO4) was added to 1.0 mM dye solution, for a total volume of 250 mL. For each treatment, a number of parameters were quantified. These were voltage, current, temperature, loss of volume, pH, electrical conductivity, concentration, optical mission spectra, chemical oxygen demand (COD), total organic carbon (TOC), and the removal ratio. Because of the increase in the sample temperature, the volume lost by evaporation was explored. The results show that the efficiency of the dye degradation by plasma is a function of treatment time. Moreover, the reactive concentration of FeSO4 and the exposition time of the plasma were varied at a constant volume, leading to the determination of the concentrations and optimal times. Considering the degradation and removal parameters, at the maximum treated time of 80 min, it found that COD was of 96.36%, TOC of 93.93%, and the removal ratio of 97.47%.

Radiation-thermometric study of isolated hot molten metal spheres by containerless and contactless measurement techniques

NASA Astrophysics Data System (ADS)

Lee, G. W.; Jeon, S.; Park, C.; Kang, D. H.; Choi, B. I.; Park, S. N.

2013-09-01

An electrostatic levitation (ESL) device is developed to study the radiation-properties of liquid metals at high temperature. The technique provides good advantage, such as fast response of temperature change on a sample, clear features of recalescence and plateau during freezing, no contamination or no reaction with environment, easy control of supercooling deducing hypercooling limit, and relatively simple analysis of thermodynamic quantities because of only radiative cooling process under vacuum. In this study, we could obtain a hypercooling limit (i.e., maximum supercooling) of liquid Ti, 341 K using the ESL. An accurate ratio of the specific heat to total hemispherical emissivity of liquid Ti was obtained by Stefan-Boltzmann law. Then, the specific heat and total hemispherical emissivity of Ti liquid metal can be estimated with the hypercooling limit and known fusion enthalpy values of Ti, which has been rarely reported.

Investigation of the hydrochlorination of SiCl4

NASA Technical Reports Server (NTRS)

Mui, J. Y. P.

1982-01-01

A research and development program on the hydrochlorination of silicon tetrachloride and metallurgical grade (m.g.) silicon metal to trichlorosilane was carried out as scheduled. Effects of pressure and temperature on this reaction are reported. The presence of HCl in the reaction product mixture was successfully analyzed. Approximately 0.1% to 0.5% HCl based on total chlorosilanes were produced by the hydrochlorination reaction. Experiments on the corrosion study were carried out to evaluate a variety of metals and alloys as the material of construction for the hydrochlorination reactor. Material includes carbon steel, nickel, copper, Alloy 400 (Monel), stainless steel (Type 304), Incoloy 800H and Hastelloy B-2. The corrosion test was carried out at reaction temperature of 500 C, pressure of 300 psig and H2/SiCl4 feed ratio of 2.0 for a total of 87 hours. Results of the corrosion test show that all the test samples achieved a weigh gain.

Performance and Operational Characteristics of a Python Turbine-propeller Engine at Simulated Altitude Conditions / Carl L. Meyer and Lavern A. Johnson

NASA Technical Reports Server (NTRS)

Meyer, Carl L; Johnson, Lavern A

1952-01-01

The performance and operational characteristics of a Python turbine-propeller engine were investigated at simulated altitude conditions in the NACA Lewis altitude wind tunnel. In the performance phase, data were obtained over a range of engine speeds and exhaust nozzle areas at altitudes from 10,000 to 40,000 feet at a single cowl-inlet ram pressure ratio; independent control of engine speed and fuel flow was used to obtain a range of powers at each engine speed. Engine performance data obtained at a given altitude could not be used to predict performance accurately at other altitudes by use of the standard air pressure and temperature generalizing factors. At a given engine speed and turbine-inlet total temperature, a greater portion of the total available energy was converted to propulsive power as the altitude increased.

Rapid production of organic fertilizer by dynamic high-temperature aerobic fermentation (DHAF) of food waste.

PubMed

Jiang, Yang; Ju, Meiting; Li, Weizun; Ren, Qingbin; Liu, Le; Chen, Yu; Yang, Qian; Hou, Qidong; Liu, Yiliang

2015-12-01

Keep composting matrix in continuous collision and friction under a relatively high-temperature can significantly accelerate the progress of composting. A bioreactor was designed according to the novel process. Using this technology, organic fertilizer could be produced within 96h. The electric conductivity (EC) and pH value reached to a stable value of 2.35mS/cm and 7.7 after 96h of fermentation. The total carbon/total nitrogen (TC/TN) and dissolved carbon/dissolved nitrogen (DC/DN) ratio was decrease from 27.3 and 36.2 to 17.4 and 7.6 respectively. In contrast, it needed 24days to achieve the similar result in traditional static composting (TSC). Compost particles with different size were analyzed to explore the rapid degradation mechanism of food waste. The evidence of anaerobic fermentation was firstly discovered in aerobic composting. Copyright © 2015 Elsevier Ltd. All rights reserved.

Feasibility study of a passive aeration reactor equipped with vertical pipes for compost stabilization of cow manure.

PubMed

Sylla, Youssouf Boundou; Kuroda, Masao; Yamada, Masayuki; Matsumoto, Naoko

2006-10-01

Pilot-scale composting was carried out with cow manure to evaluate the performances of two passive aeration systems: a conventional passive aeration system equipped with horizontal pipes and an unusual passive aeration method based on air delivery by means of vertical pipes. The effects of both types of passive aeration apparatus were investigated in order to determine the degree of composting rate by continuously monitoring temperature, moisture content, organic matter, electrical conductivity, pH and C/N ratio in the piles. Temperatures in the range of thermophily (55-65 degrees C) were reached in all runs within 1-2 days then lasting for about 1 week, a span long enough for pathogen abatement. Results suggest that passive aeration carried out by vertical pipes is more effective for air delivery into compost piles than conventional passive aeration of air adduction with horizontal pipes. The variation in the number of vertical pipes was revealed to be an important parameter for the control of composting rate and temperature. Composting rates estimated from the heat balance equation were substantially in agreement with those computed through the conversion ratio of total organic matter decrement. The conversion ratios and composting rates obtained in this study using passive aeration with vertical pipes were well aligned with those found using forced air delivery systems.

Effects of oxygen partial pressure, deposition temperature, and annealing on the optical response of CdS:O thin films as studied by spectroscopic ellipsometry

NASA Astrophysics Data System (ADS)

Junda, Maxwell M.; Grice, Corey R.; Subedi, Indra; Yan, Yanfa; Podraza, Nikolas J.

2016-07-01

Ex-situ spectroscopic ellipsometry measurements are made on radio frequency magnetron sputtered oxygenated cadmium sulfide (CdS:O) thin films. Films are deposited onto glass substrates at room temperature and at 270 °C with varying oxygen to total gas flow ratios in the sputtering ambient. Ellipsometric spectra from 0.74 to 5.89 eV are collected before and after annealing at 607 °C to simulate the thermal processes during close-space sublimation of overlying cadmium telluride in that solar cell configuration. Complex dielectric function (ɛ = ɛ1 + iɛ2) spectra are extracted for films as a function of oxygen gas flow ratio, deposition temperature, and post-deposition annealing using a parametric model accounting for critical point transitions and an Urbach tail for sub-band gap absorption. The results suggest an inverse relationship between degree of crystallinity and oxygen gas flow ratio, whereas annealing is shown to increase crystallinity in all samples. Direct band gap energies are determined from the parametric modeling of ɛ and linear extrapolations of the square of the absorption coefficient. As-deposited samples feature a range of band gap energies whereas annealing is shown to result in gap energies ranging only from 2.40 to 2.45 eV, which is close to typical band gaps for pure cadmium sulfide.

Hot gas ingestion test results of a two-poster vectored thrust concept with flow visualization in the NASA Lewis 9- by 15-foot low speed wind tunnel

NASA Technical Reports Server (NTRS)

Johns, Albert L.; Neiner, George; Bencic, Timothy J.; Flood, Joseph D.; Amuedo, Kurt C.

1990-01-01

A 9.2 percent scale STOVL hot gas ingestion model was tested in the NASA Lewis 9 x 15-foot Low-Speed Wind Tunnel. Flow visualization from the Phase 1 test program, which evaluated the hot ingestion phenomena and control techniques, is covered. The Phase 2 test program evaluated the hot gas ingestion phenomena at higher temperatures and used a laser sheet to investigate the flow field. Hot gas ingestion levels were measured for the several forward nozzle splay configurations and with flow control/life improvement devices (LIDs) which reduced the hot gas ingestion. The test was conducted at full scale nozzle pressure ratios and inlet Mach numbers. Results are presented over a range of nozzle pressure ratios at a 10 kn headwind velocity. The Phase 2 program was conducted at exhaust nozzle temperatures up to 1460 R and utilized a sheet laser system for flow visualization of the model flow field in and out of ground effects. The results reported are for nozzle exhaust temperatures up to 1160 R and contain the compressor face pressure and temperature distortions, the total pressure recovery, the inlet temperature rise, and the environmental effects of the hot gas. The environmental effects include the ground plane contours, the model airframe heating, and the location of the ground flow separation.

Optimization of Reflux Conditions for Total Flavonoid and Total Phenolic Extraction and Enhanced Antioxidant Capacity in Pandan (Pandanus amaryllifolius Roxb.) Using Response Surface Methodology

PubMed Central

Ghasemzadeh, Ali; Jaafar, Hawa Z. E.

2014-01-01

Response surface methodology was applied to optimization of the conditions for reflux extraction of Pandan (Pandanus amaryllifolius Roxb.) in order to achieve a high content of total flavonoids (TF), total phenolics (TP), and high antioxidant capacity (AC) in the extracts. Central composite experimental design with three factors and three levels was employed to consider the effects of the operation parameters, including the methanol concentration (MC, 40%–80%), extraction temperature (ET, 40–70°C), and liquid-to-solid ratio (LS ratio, 20–40 mL/g) on the properties of the extracts. Response surface plots showed that increasing these operation parameters induced the responses significantly. The TF content and AC could be maximized when the extraction conditions (MC, ET, and LS ratio) were 78.8%, 69.5°C, and 32.4 mL/g, respectively, whereas the TP content was optimal when these variables were 75.1%, 70°C, and 31.8 mL/g, respectively. Under these optimum conditions, the experimental TF and TP content and AC were 1.78, 6.601 mg/g DW, and 87.38%, respectively. The optimized model was validated by a comparison of the predicted and experimental values. The experimental values were found to be in agreement with the predicted values, indicating the suitability of the model for optimizing the conditions for the reflux extraction of Pandan. PMID:25147852

Impacts of elevated terrestrial nutrient loads and temperature on pelagic food-web efficiency and fish production.

PubMed

Lefébure, R; Degerman, R; Andersson, A; Larsson, S; Eriksson, L-O; Båmstedt, U; Byström, P

2013-05-01

Both temperature and terrestrial organic matter have strong impacts on aquatic food-web dynamics and production. Temperature affects vital rates of all organisms, and terrestrial organic matter can act both as an energy source for lower trophic levels, while simultaneously reducing light availability for autotrophic production. As climate change predictions for the Baltic Sea and elsewhere suggest increases in both terrestrial matter runoff and increases in temperature, we studied the effects on pelagic food-web dynamics and food-web efficiency in a plausible future scenario with respect to these abiotic variables in a large-scale mesocosm experiment. Total basal (phytoplankton plus bacterial) production was slightly reduced when only increasing temperatures, but was otherwise similar across all other treatments. Separate increases in nutrient loads and temperature decreased the ratio of autotrophic:heterotrophic production, but the combined treatment of elevated temperature and terrestrial nutrient loads increased both fish production and food-web efficiency. CDOM: Chl a ratios strongly indicated that terrestrial and not autotrophic carbon was the main energy source in these food webs and our results also showed that zooplankton biomass was positively correlated with increased bacterial production. Concomitantly, biomass of the dominant calanoid copepod Acartia sp. increased as an effect of increased temperature. As the combined effects of increased temperature and terrestrial organic nutrient loads were required to increase zooplankton abundance and fish production, conclusions about effects of climate change on food-web dynamics and fish production must be based on realistic combinations of several abiotic factors. Moreover, our results question established notions on the net inefficiency of heterotrophic carbon transfer to the top of the food web. © 2013 Blackwell Publishing Ltd.

A universal reduced glass transition temperature for liquids

NASA Technical Reports Server (NTRS)

Fedors, R. F.

1979-01-01

Data on the dependence of the glass transition temperature on the molecular structure for low-molecular-weight liquids are analyzed in order to determine whether Boyer's reduced glass transition temperature (1952) is a universal constant as proposed. It is shown that the Boyer ratio varies widely depending on the chemical nature of the molecule. It is pointed out that a characteristic temperature ratio, defined by the ratio of the sum of the melting temperature and the boiling temperature to the sum of the glass transition temperature and the boiling temperature, is a universal constant independent of the molecular structure of the liquid. The average value of the ratio obtained from data for 65 liquids is 1.15.

High Time Resolution Measurements of VOCs from Vehicle Cold Starts: The Air Toxic Cold Start Pulse

NASA Astrophysics Data System (ADS)

Jobson, B. T.; Huangfu, Y.; Vanderschelden, G. S.

2017-12-01

Pollutants emitted during motor vehicle cold starts, especially in winter in some climates, is a significant source of winter time air pollution. While data exist for CO, NO, and total hydrocarbon emissions from federal testing procedures for vehicle emission certification, little is known about the emission rates of individual volatile organic compounds, in particular the air toxics benzene, formaldehyde, and acetaldehyde. Little is known about the VOC speciation and temperature dependence for cold starts. The US EPA vehicle emission model MOVES assumes that cold start emissions have the same speciation profile as running emissions. We examined this assumption by measuring cold start exhaust composition for 4 vehicles fueled with E10 gasoline over a temperature range of -4°C to 10°C in winter of 2015. The extra cold start emissions were determined by comparison with emissions during engine idling. In addition to CO and NOx measurements a proton transfer reaction mass spectrometer was used to measure formaldehyde, acetaldehyde, benzene, toluene, and C2-alkylbenzenes at high time resolution to compare with the cold start emission speciation profiles used in the EPA MOVES2014 model. The results show that after the vehicle was started, CO mixing ratios can reach a few percent of the exhaust and then drop to several ppmv within 2 minutes of idling, while NOx showed different temporal behaviors among the four vehicles. VOCs displayed elevated levels during cold start and the peak mixing ratios can be two orders higher than idling phase levels. Molar emission ratios relative to toluene were used to compare with the emission ratio used in MOVES2014 and we found the formaldehyde-to-toluene emission ratio was about 0.19, which is 5 times higher than the emission ratio used in MOVES2014 and the acetaldehyde-to-toluene emission ratios were 0.86-0.89, which is 8 times higher than the ones in MOVES2014. The C2-alkylbenzene-to-toluene ratio agreed well with moves. Our results suggest that for the air toxics acetaldehyde and formaldehyde, wintertime cold temperature vehicle start emissions are likely significantly underestimated in the MOVES 2014 model.

CO line ratios in molecular clouds: the impact of environment

NASA Astrophysics Data System (ADS)

Peñaloza, Camilo H.; Clark, Paul C.; Glover, Simon C. O.; Klessen, Ralf S.

2018-04-01

Line emission is strongly dependent on the local environmental conditions in which the emitting tracers reside. In this work, we focus on modelling the CO emission from simulated giant molecular clouds (GMCs), and study the variations in the resulting line ratios arising from the emission from the J = 1-0, J = 2-1, and J = 3-2 transitions. We perform a set of smoothed particle hydrodynamics simulations with time-dependent chemistry, in which environmental conditions - including total cloud mass, density, size, velocity dispersion, metallicity, interstellar radiation field (ISRF), and the cosmic ray ionization rate (CRIR) - were systematically varied. The simulations were then post-processed using radiative transfer to produce synthetic emission maps in the three transitions quoted above. We find that the cloud-averaged values of the line ratios can vary by up to ±0.3 dex, triggered by changes in the environmental conditions. Changes in the ISRF and/or in the CRIR have the largest impact on line ratios since they directly affect the abundance, temperature, and distribution of CO-rich gas within the clouds. We show that the standard methods used to convert CO emission to H2 column density can underestimate the total H2 molecular gas in GMCs by factors of 2 or 3, depending on the environmental conditions in the clouds.

Seasonality of isoprenoid emissions from a primary rainforest in central Amazonia

DOE PAGES

Alves, Eliane G.; Jardine, Kolby; Tota, Julio; ...

2016-03-23

Tropical rainforests are an important source of isoprenoid and other volatile organic compound (VOC) emissions to the atmosphere. The seasonal variation of these compounds is however still poorly understood. In this study, vertical profiles of mixing ratios of isoprene, total monoterpenes and total sesquiterpenes, were measured within and above the canopy, in a primary rainforest in central Amazonia, using a proton transfer reaction – mass spectrometer (PTR-MS). Fluxes of these compounds from the canopy into the atmosphere were estimated from PTR-MS measurements by using an inverse Lagrangian transport model. Measurements were carried out continuously from September 2010 to January 2011,more » encompassing the dry and wet seasons. Mixing ratios were higher during the dry (isoprene – 2.68 ± 0.9 ppbv, total monoterpenes – 0.67 ± 0.3 ppbv; total sesquiterpenes – 0.09 ± 0.07 ppbv) than the wet season (isoprene – 1.66 ± 0.9 ppbv, total monoterpenes – 0.47 ± 0.2 ppbv; total sesquiterpenes – 0.03 ± 0.02 ppbv) for all compounds. Ambient air temperature and photosynthetically active radiation (PAR) behaved similarly. Daytime isoprene and total monoterpene mixing ratios were highest within the canopy, rather than near the ground or above the canopy. By comparison, daytime total sesquiterpene mixing ratios were highest near the ground. Daytime fluxes varied significantly between seasons for all compounds. The maximums for isoprene (2.53 ± 0.5 µmol m -2 h -1) and total monoterpenes (1.77 ± 0.05 µmol m -2 h -1) were observed in the late dry season, whereas the maximum for total sesquiterpenes was found during the dry-to-wet transition season (0.77 ± 0.1 µmol m -2 h -1). These flux estimates suggest that the canopy is the main source of isoprenoids emitted into the atmosphere for all seasons. However, uncertainties in turbulence parameterization near the ground could affect estimates of fluxes that come from the ground. Leaf phenology seemed to be an important driver of seasonal variation of isoprenoid emissions. Although remote sensing observations of changes in leaf area index were used to estimate leaf phenology, MEGAN 2.1 did not fully capture the behavior of seasonal emissions observed in this study. This could be a result of very local effects on the observed emissions, but also suggest that other parameters need to be better determined in biogenic volatile organic compound (BVOC) models. Our results support established findings that seasonality of isoprenoids are driven by seasonal changes in light, temperature and leaf phenology. However, they suggest that leaf phenology and its role on isoprenoid production and emission from tropical plant species needs to be better understood in order to develop mechanistic explanations for seasonal variation in emissions. This also may reduce the uncertainties of model estimates associated with the responses to environmental factors. Therefore, this study strongly encourages long-term measurements of isoprenoid emissions, environmental factors and leaf phenology from leaf to ecosystem scale, with the purpose of improving BVOC model approaches that can characterize seasonality of isoprenoid emissions from tropical rainforests.« less

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

Alves, Eliane G.; Jardine, Kolby; Tota, Julio

Tropical rainforests are an important source of isoprenoid and other volatile organic compound (VOC) emissions to the atmosphere. The seasonal variation of these compounds is however still poorly understood. In this study, vertical profiles of mixing ratios of isoprene, total monoterpenes and total sesquiterpenes, were measured within and above the canopy, in a primary rainforest in central Amazonia, using a proton transfer reaction – mass spectrometer (PTR-MS). Fluxes of these compounds from the canopy into the atmosphere were estimated from PTR-MS measurements by using an inverse Lagrangian transport model. Measurements were carried out continuously from September 2010 to January 2011,more » encompassing the dry and wet seasons. Mixing ratios were higher during the dry (isoprene – 2.68 ± 0.9 ppbv, total monoterpenes – 0.67 ± 0.3 ppbv; total sesquiterpenes – 0.09 ± 0.07 ppbv) than the wet season (isoprene – 1.66 ± 0.9 ppbv, total monoterpenes – 0.47 ± 0.2 ppbv; total sesquiterpenes – 0.03 ± 0.02 ppbv) for all compounds. Ambient air temperature and photosynthetically active radiation (PAR) behaved similarly. Daytime isoprene and total monoterpene mixing ratios were highest within the canopy, rather than near the ground or above the canopy. By comparison, daytime total sesquiterpene mixing ratios were highest near the ground. Daytime fluxes varied significantly between seasons for all compounds. The maximums for isoprene (2.53 ± 0.5 µmol m -2 h -1) and total monoterpenes (1.77 ± 0.05 µmol m -2 h -1) were observed in the late dry season, whereas the maximum for total sesquiterpenes was found during the dry-to-wet transition season (0.77 ± 0.1 µmol m -2 h -1). These flux estimates suggest that the canopy is the main source of isoprenoids emitted into the atmosphere for all seasons. However, uncertainties in turbulence parameterization near the ground could affect estimates of fluxes that come from the ground. Leaf phenology seemed to be an important driver of seasonal variation of isoprenoid emissions. Although remote sensing observations of changes in leaf area index were used to estimate leaf phenology, MEGAN 2.1 did not fully capture the behavior of seasonal emissions observed in this study. This could be a result of very local effects on the observed emissions, but also suggest that other parameters need to be better determined in biogenic volatile organic compound (BVOC) models. Our results support established findings that seasonality of isoprenoids are driven by seasonal changes in light, temperature and leaf phenology. However, they suggest that leaf phenology and its role on isoprenoid production and emission from tropical plant species needs to be better understood in order to develop mechanistic explanations for seasonal variation in emissions. This also may reduce the uncertainties of model estimates associated with the responses to environmental factors. Therefore, this study strongly encourages long-term measurements of isoprenoid emissions, environmental factors and leaf phenology from leaf to ecosystem scale, with the purpose of improving BVOC model approaches that can characterize seasonality of isoprenoid emissions from tropical rainforests.« less

Seasonality of isoprenoid emissions from a primary rainforest in central Amazonia

NASA Astrophysics Data System (ADS)

Alves, Eliane G.; Jardine, Kolby; Tota, Julio; Jardine, Angela; Yãnez-Serrano, Ana Maria; Karl, Thomas; Tavares, Julia; Nelson, Bruce; Gu, Dasa; Stavrakou, Trissevgeni; Martin, Scot; Artaxo, Paulo; Manzi, Antonio; Guenther, Alex

2016-03-01

Tropical rainforests are an important source of isoprenoid and other volatile organic compound (VOC) emissions to the atmosphere. The seasonal variation of these compounds is however still poorly understood. In this study, vertical profiles of mixing ratios of isoprene, total monoterpenes and total sesquiterpenes, were measured within and above the canopy, in a primary rainforest in central Amazonia, using a proton transfer reaction - mass spectrometer (PTR-MS). Fluxes of these compounds from the canopy into the atmosphere were estimated from PTR-MS measurements by using an inverse Lagrangian transport model. Measurements were carried out continuously from September 2010 to January 2011, encompassing the dry and wet seasons. Mixing ratios were higher during the dry (isoprene - 2.68 ± 0.9 ppbv, total monoterpenes - 0.67 ± 0.3 ppbv; total sesquiterpenes - 0.09 ± 0.07 ppbv) than the wet season (isoprene - 1.66 ± 0.9 ppbv, total monoterpenes - 0.47 ± 0.2 ppbv; total sesquiterpenes - 0.03 ± 0.02 ppbv) for all compounds. Ambient air temperature and photosynthetically active radiation (PAR) behaved similarly. Daytime isoprene and total monoterpene mixing ratios were highest within the canopy, rather than near the ground or above the canopy. By comparison, daytime total sesquiterpene mixing ratios were highest near the ground. Daytime fluxes varied significantly between seasons for all compounds. The maximums for isoprene (2.53 ± 0.5 µmol m-2 h-1) and total monoterpenes (1.77 ± 0.05 µmol m-2 h-1) were observed in the late dry season, whereas the maximum for total sesquiterpenes was found during the dry-to-wet transition season (0.77 ± 0.1 µmol m-2 h-1). These flux estimates suggest that the canopy is the main source of isoprenoids emitted into the atmosphere for all seasons. However, uncertainties in turbulence parameterization near the ground could affect estimates of fluxes that come from the ground. Leaf phenology seemed to be an important driver of seasonal variation of isoprenoid emissions. Although remote sensing observations of changes in leaf area index were used to estimate leaf phenology, MEGAN 2.1 did not fully capture the behavior of seasonal emissions observed in this study. This could be a result of very local effects on the observed emissions, but also suggest that other parameters need to be better determined in biogenic volatile organic compound (BVOC) models. Our results support established findings that seasonality of isoprenoids are driven by seasonal changes in light, temperature and leaf phenology. However, they suggest that leaf phenology and its role on isoprenoid production and emission from tropical plant species needs to be better understood in order to develop mechanistic explanations for seasonal variation in emissions. This also may reduce the uncertainties of model estimates associated with the responses to environmental factors. Therefore, this study strongly encourages long-term measurements of isoprenoid emissions, environmental factors and leaf phenology from leaf to ecosystem scale, with the purpose of improving BVOC model approaches that can characterize seasonality of isoprenoid emissions from tropical rainforests.

Seasonality of isoprenoid emissions from a primary rainforest in central Amazonia

NASA Astrophysics Data System (ADS)

Alves, E. G.; Jardine, K.; Tota, J.; Jardine, A.; Yáñez-Serrano, A. M.; Karl, T.; Tavares, J.; Nelson, B.; Gu, D.; Stavrakou, T.; Martin, S.; Manzi, A.; Guenther, A.

2015-10-01

Tropical rainforests are an important source of isoprenoid and other Volatile Organic Compound (VOC) emissions to the atmosphere. The seasonal variation of these compounds is however still poorly understood. In this study, profiles were collected of the vertical profile of mixing ratios of isoprene, total monoterpenes and total sesquiterpenes, within and above the canopy, in a primary rainforest in central Amazonia, using a Proton Transfer Reaction-Mass Spectrometer (PTR-MS). Fluxes of these compounds from the canopy into the atmosphere were estimated from PTR-MS measurements by using an inverse Lagrangian transport model. Measurements were carried out continuously from September 2010 to January 2011, encompassing the dry and wet seasons. Mixing ratios were higher during the dry (isoprene - 2.68 ± 0.9 ppbv, total monoterpenes - 0.67 ± 0.3 ppbv; total sesquiterpenes - 0.09 ± 0.07 ppbv) than the wet season (isoprene - 1.66 ± 0.9 ppbv, total monoterpenes - 0.47 ± 0.2 ppbv; total sesquiterpenes - 0.03 ± 0.02 ppbv) for all compounds. Ambient air temperature and photosynthetically active radiation (PAR) behaved similarly. Daytime isoprene and total monoterpene mixing ratios were highest within the canopy, rather than near the ground or above the canopy. By comparison, daytime total sesquiterpene mixing ratios were highest near the ground. Daytime fluxes varied significantly between seasons for all compounds. The maximums for isoprene (2.53 ± 0.5 μmol m-2 h-1) and total monoterpenes (1.77 ± 0.05 μmol m-2 h-1) were observed in the late dry season, whereas the maximum for total sesquiterpenes was found during the dry-to-wet transition season (0.77 ± 0.1 μmol m-2 h-1). These flux estimates suggest that the canopy is the main source of isoprenoids to the atmosphere for all seasons. However, uncertainties in turbulence parameterization near the ground could affect estimates of fluxes that come from the ground. Leaf phenology seemed to be an important driver of seasonal variation of isoprenoid emissions. Although remote sensing observations of changes in leaf area index were used to estimate leaf phenology, MEGAN 2.1 did not fully capture the behavior of seasonal emissions observed in this study. This could be a result of very local effects on the observed emissions, but also suggest that other parameters need to be better determined in Biogenic Volatile Organic Compound (BVOC) models. Our results support established findings that seasonality of isoprenoids are driven by seasonal changes in light, temperature and leaf phenology. However, they suggest that leaf phenology and its role on isoprenoid production and emission from tropical plant species needs to be better understood in order to develop mechanistic explanations for seasonal variation in emissions. This also may reduce the uncertainties of model estimates associated with the responses to environmental factors. Therefore, this study strongly encourages long-term measurements of isoprenoid emissions, environmental factors and leaf phenology from leaf to ecosystem scale, with the purpose of improving BVOC model approaches that can characterize seasonality of isoprenoid emissions from tropical rainforests.

Hydrothermal Oxidation of Fecal Sludge: Experimental Investigations and Kinetic Modeling.

PubMed

Hübner, Tobias; Roth, Markus; Vogel, Frédéric

2016-11-23

Hydrothermal oxidation (HTO) provides an efficient technique to completely destroy wet organic wastes. In this study, HTO was applied to treat fecal sludge at well-defined experimental conditions. Four different kinetic models were adjusted to the obtained data. Among others, a distributed activation energy model (DAEM) was applied. A total of 33 experiments were carried out in an unstirred batch reactor with pressurized air as the oxidant at temperatures of <470 °C, oxygen-to-fuel equivalence ratios between 0 and 1.9, feed concentrations between 3.9 and 9.8 mol TOC L -1 (TOC = total organic carbon), and reaction times between 86 and 1572 s. Decomposition of the fecal sludge was monitored by means of the conversion of TOC to CO 2 and CO. In the presence of oxygen, ignition of the reaction was observed around 300 °C, followed by further rapid decomposition of the organic material. The TOC was completely decomposed to CO 2 within 25 min at 470 °C and an oxygen-to-fuel equivalence ratio of 1.2. CO was formed as an intermediate product, and no other combustible products were found in the gas. At certain reaction conditions, the formation of unwanted coke and tarlike products occurred. The reaction temperature and oxygen-to-fuel equivalence ratio showed a significant influence on TOC conversion, while the initial TOC concentration did not. Conversion of TOC to CO 2 could be well described with a first-order rate law and an activation energy of 39 kJ mol -1 .

Hydrothermal Oxidation of Fecal Sludge: Experimental Investigations and Kinetic Modeling

PubMed Central

2016-01-01

Hydrothermal oxidation (HTO) provides an efficient technique to completely destroy wet organic wastes. In this study, HTO was applied to treat fecal sludge at well-defined experimental conditions. Four different kinetic models were adjusted to the obtained data. Among others, a distributed activation energy model (DAEM) was applied. A total of 33 experiments were carried out in an unstirred batch reactor with pressurized air as the oxidant at temperatures of <470 °C, oxygen-to-fuel equivalence ratios between 0 and 1.9, feed concentrations between 3.9 and 9.8 molTOC L–1 (TOC = total organic carbon), and reaction times between 86 and 1572 s. Decomposition of the fecal sludge was monitored by means of the conversion of TOC to CO2 and CO. In the presence of oxygen, ignition of the reaction was observed around 300 °C, followed by further rapid decomposition of the organic material. The TOC was completely decomposed to CO2 within 25 min at 470 °C and an oxygen-to-fuel equivalence ratio of 1.2. CO was formed as an intermediate product, and no other combustible products were found in the gas. At certain reaction conditions, the formation of unwanted coke and tarlike products occurred. The reaction temperature and oxygen-to-fuel equivalence ratio showed a significant influence on TOC conversion, while the initial TOC concentration did not. Conversion of TOC to CO2 could be well described with a first-order rate law and an activation energy of 39 kJ mol–1. PMID:28539700

Effect of operating conditions on the exhaust emissions from a gas turbine combustor

NASA Technical Reports Server (NTRS)

Briehl, D.; Papathakos, L.; Strancar, R. J.

1972-01-01

Exhaust concentrations of total unburned hydrocarbons, carbon monoxide, and nitric oxide were measured from a single J-57 combustor liner installed in a 30 diameter test section. Tests were conducted over a range of inlet total pressures from 1 to 20 atmospheres, inlet total temperatures from 310 to 590 K, reference velocities from 8 to m/sec, and fuel-air ratios from 0.004 to 0.015. Most of the data were obtained using ASTM A-1 fuel; however, a limited number of tests was performed with natural gas fuel. Combustion efficiency and emission levels are correlated with operating conditions. Sampling error at operating conditions for which combustion efficiency was below about 90 percent resulted in abnormally low readings for hydrocarbon emissions.

Effect of Air Cooling of Turbine Disk on Power and Efficiency of Turbine from Turbo Engineering Corporation TT13-18 Turbosupercharger.

NASA Technical Reports Server (NTRS)

Berkey, William E.

1949-01-01

An investigation was conducted to determine the effect of turbine-disk cooling with air on the efficiency and the power output of the radial-flow turbine from the Turbo Engineering Corporation TT13-18 turbosupercharger. The turbine was operated at a constant range of ratios of turbine-inlet total pressure to turbine-outlet static pressure of 1,5 and 2.0, turbine-inlet total pressure of 30 inches mercury absolute, turbine-inlet total temperature of 12000 to 20000 R, and rotor speeds of 6000 to 22,000 rpm, Over the normal operating range of the turbine, varying the corrected cooling-air weight flow from approximately 0,30 to 0.75 pound per second produced no measurable effect on the corrected turbine shaft horsepower or the turbine shaft adiabatic efficiency. Varying the turbine-inlet total temperature from 12000 to 20000 R caused no measurable change in the corrected cooling-air weight flow. Calculations indicated that the cooling-air pumping power in the disk passages was small and was within the limits of the accuracy of the power measurements. For high turbine power output, the power loss to the compressor for compressing the cooling air was approximately 3 percent of the total turbine shaft horsepower.

Solar sustained plasma/absorber conceptual design

NASA Technical Reports Server (NTRS)

Rodgers, R. J.; Krascella, N. L.; Kendall, J. S.

1979-01-01

A space power system concept was evaluated which uses concentrated solar energy to heat a working fluid to temperatures as high as 4000 K. The high temperature working fluid could be used for efficient electric power production in advanced thermal or magnetohydrodynamic conversion cycles. Energy absorber configurations utilizing particles or cesium vapor absorber material were investigaed. Results of detailed radiant heat transfer calculations indicated approximately 86 percent of the incident solar energy could be absorbed within a 12-cm-dia flowing stream of gas borne carbon particles. Calculated total energy absorption in the cesium vapor seeded absorber configuration ranged from 34 percent to 64 percent of the incident solar energy. Solar flux concentration ratios of between approximately 3000 and 10,000 will be required to sustain absorber temperatures in the range from 3000 K to 4000 K.

Comparative net energy ratio analysis of pellet produced from steam pretreated biomass from agricultural residues and energy crops

DOE PAGES

Shahrukh, Hassan; Oyedun, Adetoyese Olajire; Kumar, Amit; ...

2016-04-05

Here, a process model was developed to determine the net energy ratio (NER) for production of pellets from steam pretreated agricultural residue (AR) and energy crop (i.e. switchgrass in this case). The NER is a ratio of the net energy output to the total net energy input from non-renewable energy sources into a system. Scenarios were developed to measure the effects of temperature and level of steam pretreatment on the NER of steam pretreated AR- and switch grass-based pellets. The NER for the base case at 6 kg h -1 is 1.76 and 1.37 for steam-pretreated AR- and switchgrass-based pellets,more » respectively. The reason behind the difference is that more energy is required to dry switchgrass pellets than AR pellets. The sensitivity analysis for the model shows that the optimum temperature for steam pretreatment is 160 C with 50% pretreatment (half the feedstock is pretreated, while the rest is undergoes regular pelletization). The uncertainty results for NER for steam pretreated AR and switch grass pellets are 1.62 ± 0.10 and 1.42 ± 0.11, respectively.« less

The oceanic origin of path-independent carbon budgets.

PubMed

MacDougall, Andrew H

2017-09-04

Virtually all Earth system models (ESM) show a near proportional relationship between cumulative emissions of CO 2 and change in global mean temperature, a relationship which is independent of the emissions pathway taken to reach a cumulative emissions total. The relationship, which has been named the Transient Climate Response to Cumulative CO 2 Emissions (TCRE), gives rise to the concept of a 'carbon budget'. That is, a finite amount of carbon that can be burnt whilst remaining below some chosen global temperature change threshold, such as the 2.0 °C target set by the Paris Agreement. Here we show that the path-independence of TCRE arises from the partitioning ratio of anthropogenic carbon between the ocean and the atmosphere being almost the same as the partitioning ratio of enhanced radiative forcing between the ocean and space. That these ratios are so close in value is a coincidence unique to CO 2 . The simple model used here is underlain by many assumptions and simplifications but does reproduce key aspects of the climate system relevant to the path-independence of carbon budgets. Our results place TCRE and carbon budgets on firm physical foundations and therefore help validate the use of these metrics for climate policy.

Measurement and Empirical Correlation of Transpiration-Cooling Parameters on a 25 degree Cone in a Turbulent Boundary Layer in Both Free Flight and a Hot-Gas Jet

NASA Technical Reports Server (NTRS)

Walton, Thomas E., Jr.; Rashis, Bernard

1961-01-01

Transpiration-cooling parameters are presented for a turbulent boundary layer on a cone configuration with a total angle of 250 which was tested in both free flight and in an ethylene-heated high-temperature jet at a Mach number of 2.0. The flight-tested cone was flown to a maximum Mach number of 4.08 and the jet tests were conducted at stagnation temperatures ranging from 937 R to 1,850 R. In general, the experimental heat transfer was in good agreement with the theoretical values. Inclusion of the ratio of local stream temperature to wall temperature in the nondimensional flow rate parameter enabled good correlation of both sets of transpiration data. The measured pressure at the forward station coincided with the theoretical pressure over a sharp cone; however, the measured pressure increased with distance from the nose tip.

Solar wind helium ions - Observations of the Helios solar probes between 0.3 and 1 AU

NASA Technical Reports Server (NTRS)

Marsch, E.; Rosenbauer, H.; Schwenn, R.; Muehlhaeuser, K.-H.; Neubauer, F. M.

1982-01-01

A Helios solar probe survey of solar wind helium ion velocity distributions and derived parameters between 0.3 and 1 AU is presented. Distributions in high-speed wind are found to generally have small total anisotropies, with some indication that, in the core part, the temperatures are greater parallel rather than perpendicular to the magnetic field. The anisotropy tends to increase with heliocentric radial distance, and the average dependence of helium ion temperatures on radial distance from the sun is described by a power law. Differential ion speeds with values of more than 150 km/sec are observed near perihelion, or 0.3 AU. The role of Coulomb collisions in limiting differential ion speeds and the ion temperature ratio is investigated, and it is found that collisions play a distinct role in low-speed wind, by limiting both differential ion velocity and temperature.

Lipidome and metabolome analysis of fresh tobacco leaves in different geographical regions using liquid chromatography-mass spectrometry.

PubMed

Li, Lili; Lu, Xin; Zhao, Jieyu; Zhang, Junjie; Zhao, Yanni; Zhao, Chunxia; Xu, Guowang

2015-07-01

The combination of the lipidome and the metabolome can provide much more information in plant metabolomics studies. A method for the simultaneous extraction of the lipidome and the metabolome of fresh tobacco leaves was developed. Method validation was performed on the basis of the optimal ratio of methanol to methyl tert-butyl ether to water (37:45:68) from the design of experiments. Good repeatability was obtained. We found that 92.2% and 91.6% of the peaks for the lipidome and the metabolome were within a relative standard deviation of 20%, accounting for 94.6% and 94.6% of the total abundance, respectively. The intraday and interday precisions were also satisfactory. A total of 230 metabolites, including 129 lipids, were identified. Significant differences were found in lipidomic and metabolomic profiles of fresh tobacco leaves in different geographical regions. Highly unsaturated galactolipids, phosphatidylethanolamines, predominant phosphatidylcholines, most of the polyphenols, amino acids, and polyamines had a higher content in Yunnan province, and low-unsaturation-degree galactolipids, triacylglycerols, glucosylceramides with trihydroxy long-chain bases, acylated sterol glucosides, and some organic acids were more abundant in Henan province. Correlation analysis between differential metabolites and climatic factors indicated the vital importance of temperature. The fatty acid unsaturation degree of galactolipids could be influenced by temperature. Accumulation of polyphenols and decreases in the ratios of stigmasterols to sitosterols and glucosylstigmasterols to glucosylsitosterols were also correlated with lower temperature in Yunnan province. Furthermore, lipids were more sensitive to climatic variations than other metabolites.

Vapor pressure and vapor fractionation of silicate melts of tektite composition

USGS Publications Warehouse

Walter, Louis S.; Carron, M.K.

1964-01-01

The total vapor pressure of Philippine tektite melts of approximately 70 per cent silica has been determined at temperatures ranging from 1500 to 2100??C. This pressure is 190 ?? 40 mm Hg at 1500??C, 450 ?? 50 mm at 1800??C and 850 ?? 70 mm at 2100?? C. Determinations were made by visually observing the temperature at which bubbles began to form at a constant low ambient pressure. By varying the ambient pressure, a boiling point curve was constructed. This curve differs from the equilibrium vapor pressure curve due to surface tension effects. This difference was evaluated by determining the equilibrium bubble size in the melt and calculating the pressure due to surface tension, assuming the latter to be 380 dyn/cm. The relative volatility from tektite melts of the oxides of Na, K, Fe, Al and Si has been determined as a function of temperature, total pressure arid roughly, of oxygen fugacity. The volatility of SiO2 is decreased and that of Na2O and K2O is increased in an oxygen-poor environment. Preliminary results indicate that volatilization at 2100??C under atmospheric pressure caused little or no change in the percentage Na2O and K2O. The ratio Fe3 Fe2 of the tektite is increased in ambient air at a pressure of 9 ?? 10-4 mm Hg (= 106.5 atm O2, partial pressure) at 2000??C. This suggests that tektites were formed either at lower oxygen pressures or that they are a product of incomplete oxidation of parent material with a still lower ferricferrous ratio. ?? 1964.

Temperature structure in the Perseus cluster core observed with Hitomi

NASA Astrophysics Data System (ADS)

Hitomi Collaboration; Aharonian, Felix; Akamatsu, Hiroki; Akimoto, Fumie; Allen, Steven W.; Angelini, Lorella; Audard, Marc; Awaki, Hisamitsu; Axelsson, Magnus; Bamba, Aya; Bautz, Marshall W.; Blandford, Roger; Brenneman, Laura W.; Brown, Gregory V.; Bulbul, Esra; Cackett, Edward M.; Chernyakova, Maria; Chiao, Meng P.; Coppi, Paolo S.; Costantini, Elisa; de Plaa, Jelle; de Vries, Cor P.; den Herder, Jan-Willem; Done, Chris; Dotani, Tadayasu; Ebisawa, Ken; Eckart, Megan E.; Enoto, Teruaki; Ezoe, Yuichiro; Fabian, Andrew C.; Ferrigno, Carlo; Foster, Adam R.; Fujimoto, Ryuichi; Fukazawa, Yasushi; Furukawa, Maki; Furuzawa, Akihiro; Galeazzi, Massimiliano; Gallo, Luigi C.; Gandhi, Poshak; Giustini, Margherita; Goldwurm, Andrea; Gu, Liyi; Guainazzi, Matteo; Haba, Yoshito; Hagino, Kouichi; Hamaguchi, Kenji; Harrus, Ilana M.; Hatsukade, Isamu; Hayashi, Katsuhiro; Hayashi, Takayuki; Hayashida, Kiyoshi; Hiraga, Junko S.; Hornschemeier, Ann; Hoshino, Akio; Hughes, John P.; Ichinohe, Yuto; Iizuka, Ryo; Inoue, Hajime; Inoue, Yoshiyuki; Ishida, Manabu; Ishikawa, Kumi; Ishisaki, Yoshitaka; Iwai, Masachika; Kaastra, Jelle; Kallman, Tim; Kamae, Tsuneyoshi; Kataoka, Jun; Kato, Yuichi; Katsuda, Satoru; Kawai, Nobuyuki; Kelley, Richard L.; Kilbourne, Caroline A.; Kitaguchi, Takao; Kitamoto, Shunji; Kitayama, Tetsu; Kohmura, Takayoshi; Kokubun, Motohide; Koyama, Katsuji; Koyama, Shu; Kretschmar, Peter; Krimm, Hans A.; Kubota, Aya; Kunieda, Hideyo; Laurent, Philippe; Lee, Shiu-Hang; Leutenegger, Maurice A.; Limousin, Olivier; Loewenstein, Michael; Long, Knox S.; Lumb, David; Madejski, Greg; Maeda, Yoshitomo; Maier, Daniel; Makishima, Kazuo; Markevitch, Maxim; Matsumoto, Hironori; Matsushita, Kyoko; McCammon, Dan; McNamara, Brian R.; Mehdipour, Missagh; Miller, Eric D.; Miller, Jon M.; Mineshige, Shin; Mitsuda, Kazuhisa; Mitsuishi, Ikuyuki; Miyazawa, Takuya; Mizuno, Tsunefumi; Mori, Hideyuki; Mori, Koji; Mukai, Koji; Murakami, Hiroshi; Mushotzky, Richard F.; Nakagawa, Takao; Nakajima, Hiroshi; Nakamori, Takeshi; Nakashima, Shinya; Nakazawa, Kazuhiro; Nobukawa, Kumiko K.; Nobukawa, Masayoshi; Noda, Hirofumi; Odaka, Hirokazu; Ohashi, Takaya; Ohno, Masanori; Okajima, Takashi; Ota, Naomi; Ozaki, Masanobu; Paerels, Frits; Paltani, Stéphane; Petre, Robert; Pinto, Ciro; Porter, Frederick S.; Pottschmidt, Katja; Reynolds, Christopher S.; Safi-Harb, Samar; Saito, Shinya; Sakai, Kazuhiro; Sasaki, Toru; Sato, Goro; Sato, Kosuke; Sato, Rie; Sawada, Makoto; Schartel, Norbert; Serlemtsos, Peter J.; Seta, Hiromi; Shidatsu, Megumi; Simionescu, Aurora; Smith, Randall K.; Soong, Yang; Stawarz, Łukasz; Sugawara, Yasuharu; Sugita, Satoshi; Szymkowiak, Andrew; Tajima, Hiroyasu; Takahashi, Hiromitsu; Takahashi, Tadayuki; Takeda, Shiníchiro; Takei, Yoh; Tamagawa, Toru; Tamura, Takayuki; Tanaka, Takaaki; Tanaka, Yasuo; Tanaka, Yasuyuki T.; Tashiro, Makoto S.; Tawara, Yuzuru; Terada, Yukikatsu; Terashima, Yuichi; Tombesi, Francesco; Tomida, Hiroshi; Tsuboi, Yohko; Tsujimoto, Masahiro; Tsunemi, Hiroshi; Tsuru, Takeshi Go; Uchida, Hiroyuki; Uchiyama, Hideki; Uchiyama, Yasunobu; Ueda, Shutaro; Ueda, Yoshihiro; Uno, Shiníchiro; Urry, C. Megan; Ursino, Eugenio; Watanabe, Shin; Werner, Norbert; Wilkins, Dan R.; Williams, Brian J.; Yamada, Shinya; Yamaguchi, Hiroya; Yamaoka, Kazutaka; Yamasaki, Noriko Y.; Yamauchi, Makoto; Yamauchi, Shigeo; Yaqoob, Tahir; Yatsu, Yoichi; Yonetoku, Daisuke; Zhuravleva, Irina; Zoghbi, Abderahmen

2018-03-01

The present paper explains the temperature structure of X-ray emitting plasma in the core of the Perseus cluster based on 1.8-20.0 keV data obtained with the Soft X-ray Spectrometer (SXS) on board the Hitomi Observatory. A series of four observations was carried out, with a total effective exposure time of 338 ks that covered a central region of ˜7΄ in diameter. SXS was operated with an energy resolution of ˜5 eV (full width at half maximum) at 5.9 keV. Not only fine structures of K-shell lines in He-like ions, but also transitions from higher principal quantum numbers were clearly resolved from Si through Fe. That enabled us to perform temperature diagnostics using the line ratios of Si, S, Ar, Ca, and Fe, and to provide the first direct measurement of the excitation temperature and ionization temperature in the Perseus cluster. The observed spectrum is roughly reproduced by a single-temperature thermal plasma model in collisional ionization equilibrium, but detailed line-ratio diagnostics reveal slight deviations from this approximation. In particular, the data exhibit an apparent trend of increasing ionization temperature with the atomic mass, as well as small differences between the ionization and excitation temperatures for Fe, the only element for which both temperatures could be measured. The best-fit two-temperature models suggest a combination of 3 and 5 keV gas, which is consistent with the idea that the observed small deviations from a single-temperature approximation are due to the effects of projecting the known radial temperature gradient in the cluster core along the line of sight. A comparison with the Chandra/ACIS and the XMM-Newton/RGS results, on the other hand, suggests that additional lower-temperature components are present in the intracluster medium (ICM), but not detectable with Hitomi/SXS giving its 1.8-20 keV energy band.

New Examination of the Traditional Raman Lidar Technique II: Temperature Dependence Aerosol Scattering Ratio and Water Vapor Mixing Ratio Equations

NASA Technical Reports Server (NTRS)

Whiteman, David N.; Abshire, James B. (Technical Monitor)

2002-01-01

In a companion paper, the temperature dependence of Raman scattering and its influence on the Raman water vapor signal and the lidar equations was examined. New forms of the lidar equation were developed to account for this temperature sensitivity. Here we use those results to derive the temperature dependent forms of the equations for the aerosol scattering ratio, aerosol backscatter coefficient, extinction to backscatter ratio and water vapor mixing ratio. Pertinent analysis examples are presented to illustrate each calculation.

The effect of Cu/Zn molar ratio on CO{sub 2} hydrogenation over Cu/ZnO/ZrO{sub 2}/Al{sub 2}O{sub 3} catalyst

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

Shaharun, Salina, E-mail: salinashaharun@gmail.com, E-mail: maizats@petronas.com.my; Shaharun, Maizatul S., E-mail: salinashaharun@gmail.com, E-mail: maizats@petronas.com.my; Taha, Mohd F., E-mail: faisalt@petronas.com.my

2014-10-24

Catalytic hydrogenation of carbon dioxide (CO{sub 2}) to methanol is an attractive way to recycle and utilize CO{sub 2}. A series of Cu/ZnO/Al{sub 2}O{sub 3}/ZrO{sub 2} catalysts (CZAZ) containing different molar ratios of Cu/Zn were prepared by the co-precipitation method and investigated in a stirred slurry autoclave system. The catalysts were characterized by temperature-programmed reduction (TPR), field emission scanning electron microscopy-energy dispersive analysis (FESEM-EDX), X-ray diffraction (XRD) and N{sub 2} adsorption-desorption. Higher surface area, SA{sub BET} values (42.6–59.9 m{sup 2}/g) are recorded at low (1) and high (5) Cu/Zn ratios with the minimum value of 35.71 m{sup 2}/g found formore » a Cu/Zn of 3. The reducibility of the metal oxides formed after calcination of catalyst samples was also affected due to change in metal-support interaction. At a low reaction temperature of 443 K, total gas pressure of 3.0 MPa and 0.1 g/mL of the CZAZ catalyst, the selectivity to methanol decreased as the Cu/Zn molar ratio increased, and the maximum selectivity of 67.73 was achieved at Cu/Zn molar ratio of 1. With a reaction time of 3h, the best performing catalyst was CZAZ75 with Cu/Zn molar ratio of 5 giving methanol yield of 79.30%.« less

Effects of canola meal pellet conditioning temperature and time on ruminal and intestinal digestion, hourly effective degradation ratio, and potential nitrogen to energy synchronization in dairy cows.

PubMed

Huang, Xuewei; Khan, Nazir A; Zhang, Xuewei; Yu, Peiqiang

2015-12-01

The increase in bio-oil production in North America has resulted in millions of tonnes of co-products: canola meal and carinata meal. Little research has been conducted to determine the effect of pellet conditioning temperature, time, and their interaction on processing-induced changes in nutrient digestibility in the rumen and intestine (in vitro) of dairy cattle. The objectives of this study were to investigate the effects of conditioning temperature (70, 80, and 90°C), time (50 and 75 s), and their interaction (temperature × time) during the pelleting of canola meal on (1) rumen degradation kinetics and effective rumen degradability of dry matter, crude protein (CP), and neutral detergent fiber; (2) intestinal digestibility of rumen-undegradable protein (RUP); and (3) hourly effective rumen degradation ratio and potential N to energy synchronization in dairy cattle. The results showed that the temperature and duration of pellet conditioning significantly altered the degradation characteristics of nutrients in the rumen. Pelleting increased CP degradation in the rumen, and CP digestion site was shifted to the rumen rather than to the small intestine. When conditioning temperature was set 80°C, the rumen degradation of CP and neutral detergent fiber was highest, but postrumen digestion was lowest. With respect to intestinal digestion, the available CP for intestinal digestion became less because of reduced RUP supply to the small intestine. The pelleting process tended to significantly affect the intestinal digestibility of RUP. However, the total digestible CP content of canola meal was not affected. In conclusion, pelleting induced changes in rumen and intestinal digestion profiles, and altered the potential N to energy synchronization and hourly effective rumen degradation ratio of canola meal in dairy cattle. Copyright © 2015 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Nitrogen uptake by phytoplankton in surface waters of the Indian sector of Southern Ocean during austral summer

NASA Astrophysics Data System (ADS)

Tripathy, S. C.; Patra, Sivaji; Vishnu Vardhan, K.; Sarkar, A.; Mishra, R. K.; Anilkumar, N.

2018-03-01

This study reports the nitrogen uptake rate (using 15N tracer) of phytoplankton in surface waters of different frontal zones in the Indian sector of the Southern Ocean (SO) during austral summer of 2013. The investigated area encompasses four major frontal systems, i.e., the subtropical front (STF), subantarctic front (SAF), polar front-1 (PF1) and polar front-2 (PF2). Southward decrease of surface water temperature was observed, whereas surface salinity did not show any significant trend. Nutrient (NO3 - and SiO4 4-) concentrations increased southward from STF to PF; while ammonium (NH4 +), nitrite (NO2 -) and phosphate (PO4 3-) remained comparatively stable. Analysis of nutrient ratios indicated potential N-limited conditions at the STF and SAF but no such scenario was observed for PF. In terms of phytoplankton biomass, PF1 was found to be the most productive followed by SAF, whereas PF2 was the least productive region. Nitrate uptake rate increased with increasing latitude, as no systematic spatial variation was discerned for NH4 + and urea (CO(NH2)2). Linear relationship between nitrate and total N-uptake reveals that the studied area is capable of exporting up to 60% of the total production to the deep ocean if the environmental settings are favorable. Like N-uptake rates the f-ratio also increased towards PF region indicating comparatively higher new production in the PF than in the subtropics. The moderately high average f-ratio (0.53) indicates potentially near equal contributions by new production and regenerated production to the total productivity in the study area. Elevation in N-uptake rates with declining temperature suggests that the SO with its vast quantity of cool water could play an important role in drawing down the atmospheric CO2 through the "solubility pump".

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

Shahrukh, Hassan; Oyedun, Adetoyese Olajire; Kumar, Amit

In this study, a process model was developed to determine the net energy ratio (NER) for both regular and steam-pretreated pellet production from ligno-cellulosic biomass. NER is a ratio of the net energy output to the total net energy input from non-renewable energy source into the system. Scenarios were developed to measure the effect of temperature and level of steam pretreatment on the NER of both production processes. The NER for the base case at 6 kg h –1 is 1.29 and 5.0 for steam-pretreated and regular pellet production respectively. However, at the large scale NER would improve. The majormore » factor for NER is energy for steam and drying unit. The sensitivity analysis for the model shows that the optimum temperature for steam pretreatment is 200 °C with 50% pretreatment (Steam pretreating 50% feed stock, while the rest is undergoing regular pelletization). Uncertainty result for steam pretreated and regular pellet is 1.35 ± 0.09 and 4.52 ± 0.34 respectively.« less

Nitrogen-removal efficiency of a novel aerobic denitrifying bacterium, Pseudomonas stutzeri strain ZF31, isolated from a drinking-water reservoir.

PubMed

Huang, Tinglin; Guo, Lin; Zhang, Haihan; Su, Junfeng; Wen, Gang; Zhang, Kai

2015-11-01

An aerobic denitrifier, identified as Pseudomonas stutzeri strain ZF31, was isolated from the Zhoucun drinking-water reservoir. Strain ZF31 removed 97% of nitrate nitrogen after 16h, without nitrite accumulation. Sequence amplification indicated the presence of the denitrification genes napA, nirS, norB, and nosZ. Nitrogen balance analysis revealed that approximately 75% of the initial nitrogen was removed as gas products. Response surface methodology (RSM) experiments showed that maximum removal of total nitrogen (TN) occurred at pH 8.23, a C/N ratio of 6.68, temperature of 27.72°C, and with shaking at 54.15rpm. The TN removal rate at low C/N ratio (i.e., 3) and low temperature (i.e., 10°C) was 73.30% and 60.08%, respectively. These results suggest that strain ZF31 has potential applications for the bioremediation of slightly polluted drinking-water reservoirs. Copyright © 2015 Elsevier Ltd. All rights reserved.

Optimization of Biomass Gasification Process for F-T Bio-Diesel Synthesys

NASA Astrophysics Data System (ADS)

Song, Jae Hun; Sung, Yeon Kyung; Yu, Tae U.; Choi, Young Tae; Lee, Uen Do

The characteristics of biomass steam gasification were investigated to make an optimum syngas for Fischer Tropsch (F-T) synthesis of bio-diesel. Korean pine wood chip was used as a fuel and the experiment was conducted in a lab scale bubbling fluidized bed (0.1m LD. x 3.Omheight). Gas composition was evaluated by changing operating parameters such as gasifier temperature, and steam to fuel ratio. Major syngas was monitored by on-line gas analyzer (ND-IR spectroscopy) and gas chromatography (GC). As the temperature of gasifier increases hydrogen in the syngas increases while CO in the product gas decreases. The low concentration of sulfur compound and nitrogen in the product gas shows the potential advantages in the purification process of the syngas for F-T process. Optimum operating condition of the gasifier was found concerning the following gas cleaning and F-T process; H2-CO ratio and total gas yield increase while decreasing methane and CO2 concentrations in the syngas.

Effect of substrate temperature and gas flow ratio on the nanocomposite TiAlBN coating

NASA Astrophysics Data System (ADS)

Rosli, Z. M.; Kwan, W. L.; Juoi, J. M.

2016-07-01

Nanocomposite TiAlBN (nc-TiAlBN) coatings were successfully deposited via RF magnetron sputtering by varying the nitrogen-to-total gas flow ratio (RN), and substrate temperature (TS). All coatings were deposited on AISI 316 substrates using single Ti-Al-BN hot-pressed disc as a target. The grain size, phases, and chemical composition of the coatings were evaluated using glancing angle X-ray diffraction analysis (GAXRD) and X-ray photoelectron spectroscopy (XPS). Results showed that the grains size of the deposited nc-TiAlBN coatings were in the range of 3.5 to 5.7 nm and reached a nitride saturation state as early as 15 % RN. As the nitrogen concentration decreases, boron concentration increased from 9 at.% to 16.17 at.%. and thus, increase the TiB2 phase within the coatings. The TS, however, showed no significant effect either on the crystallographic structure, grain size, or in the chemical composition of the deposited nc-TiAlBN coating.

Mesoporous silica obtained with methyltriethoxysilane as co-precursor in alkaline medium

NASA Astrophysics Data System (ADS)

Putz, Ana-Maria; Wang, Kunzhou; Len, Adél; Plocek, Jiri; Bezdicka, Petr; Kopitsa, Gennady P.; Khamova, Tamara V.; Ianăşi, Cătălin; Săcărescu, Liviu; Mitróová, Zuzana; Savii, Cecilia; Yan, Minhao; Almásy, László

2017-12-01

Mesoporous silica particles have been synthesized by sol-gel method from tetraethoxysilane (tetraethylorthosilicate, TEOS) and methyltriethoxysilane (MTES), in ethanol and water mixture, at different ratios of the of the silica precursors. Ammonia was used as catalyst at room temperature and hexadecyltrimethylammonium bromide (cetyltrimethylammonium bromide, CTAB) as the structure directing agent. Nitrogen sorption, X-ray diffraction and small-angle neutron scattering gave information on the evolution of the gel structure and pore morphologies in the function of MTES/TEOS molar ratio. Thermogravimetric and differential thermal analysis showed that with addition of MTES the exothermic peak indicating the oxidation of the low molecular weight organic fragments shift to higher temperature. A room-temperature, one-pot synthesis of MCM-41 type materials is presented, in which the variation of the MTES concentration allows to change the hydrophobicity, preserving the specific properties materials, like the ordered pore structure, large specific surface area and high porosity. Specifically, the obtained materials had cylindrical pores, specific surface areas up to 1101 m2/g and total pore volumes up to 0.473 cm3/g. The obtained mesoporous materials are susceptible for further functionalization to improve their selective uptake of guest species in drug delivery applications.

Estimation of postfire nutrient loss in the Florida everglades.

PubMed

Qian, Y; Miao, S L; Gu, B; Li, Y C

2009-01-01

Postfire nutrient release into ecosystem via plant ash is critical to the understanding of fire impacts on the environment. Factors determining a postfire nutrient budget are prefire nutrient content in the combustible biomass, burn temperature, and the amount of combustible biomass. Our objective was to quantitatively describe the relationships between nutrient losses (or concentrations in ash) and burning temperature in laboratory controlled combustion and to further predict nutrient losses in field fire by applying predictive models established based on laboratory data. The percentage losses of total nitrogen (TN), total carbon (TC), and material mass showed a significant linear correlation with a slope close to 1, indicating that TN or TC loss occurred predominantly through volatilization during combustion. Data obtained in laboratory experiments suggest that the losses of TN, TC, as well as the ratio of ash total phosphorus (TP) concentration to leaf TP concentration have strong relationships with burning temperature and these relationships can be quantitatively described by nonlinear equations. The potential use of these nonlinear models relating nutrient loss (or concentration) to temperature in predicting nutrient concentrations in field ash appear to be promising. During a prescribed fire in the northern Everglades, 73.1% of TP was estimated to be retained in ash while 26.9% was lost to the atmosphere, agreeing well with the distribution of TP during previously reported wild fires. The use of predictive models would greatly reduce the cost associated with measuring field ash nutrient concentrations.

Free compressible jet investigation

NASA Astrophysics Data System (ADS)

De Gregorio, Fabrizio

2014-03-01

The nozzle pressure ratio (NPR) effect on a supersonic turbulent jet was investigated. A dedicated convergent/divergent nozzle together with a flow feeding system was designed and manufactured. A nozzle Mach exit of M j = 1.5 was selected in order to obtain a convective Mach number of M c = 0.6. The flow was investigated for over-expanded, correctly expanded and under-expanded jet conditions. Mach number, total temperature and flow velocity measurements were carried out in order to characterise the jet behaviour. The inlet conditions of the jet flow were monitored in order to calculate the nozzle exit speed of sound and evaluate the mean Mach number distribution starting from the flow velocity data. A detailed analysis of the Mach results obtained by a static Pitot probe and by a particle image velocimetry measurement system was carried out. The mean flow velocity was investigated, and the axial Mach decay and the spreading rate were associated with the flow structures and with the compressibility effects. Aerodynamics of the different jet conditions was evaluated, and the shock cells structures were detected and discussed correlating the jet structure to the flow fluctuation and local turbulence. The longitudinal and radial distribution of the total temperature was investigated, and the temperature profiles were analysed and discussed. The total temperature behaviour was correlated to the turbulent phenomena and to the NPR jet conditions. Self-similarity condition was encountered and discussed for the over-expanded jet. Compressibility effects on the local turbulence, on the turbulent kinetic energy and on the Reynolds tensor were discussed.

Spectral ratio method for measuring emissivity

USGS Publications Warehouse

Watson, K.

1992-01-01

The spectral ratio method is based on the concept that although the spectral radiances are very sensitive to small changes in temperature the ratios are not. Only an approximate estimate of temperature is required thus, for example, we can determine the emissivity ratio to an accuracy of 1% with a temperature estimate that is only accurate to 12.5 K. Selecting the maximum value of the channel brightness temperatures is an unbiased estimate. Laboratory and field spectral data are easily converted into spectral ratio plots. The ratio method is limited by system signal:noise and spectral band-width. The images can appear quite noisy because ratios enhance high frequencies and may require spatial filtering. Atmospheric effects tend to rescale the ratios and require using an atmospheric model or a calibration site. ?? 1992.

Achieving temperature-size changes in a unicellular organism

PubMed Central

Forster, Jack; Hirst, Andrew G; Esteban, Genoveva F

2013-01-01

The temperature-size rule (TSR) is an intraspecific phenomenon describing the phenotypic plastic response of an organism size to the temperature: individuals reared at cooler temperatures mature to be larger adults than those reared at warmer temperatures. The TSR is ubiquitous, affecting >80% species including uni- and multicellular groups. How the TSR is established has received attention in multicellular organisms, but not in unicells. Further, conceptual models suggest the mechanism of size change to be different in these two groups. Here, we test these theories using the protist Cyclidium glaucoma. We measure cell sizes, along with population growth during temperature acclimation, to determine how and when the temperature-size changes are achieved. We show that mother and daughter sizes become temporarily decoupled from the ratio 2:1 during acclimation, but these return to their coupled state (where daughter cells are half the size of the mother cell) once acclimated. Thermal acclimation is rapid, being completed within approximately a single generation. Further, we examine the impact of increased temperatures on carrying capacity and total biomass, to investigate potential adaptive strategies of size change. We demonstrate no temperature effect on carrying capacity, but maximum supported biomass to decrease with increasing temperature. PMID:22832346

Radiant heat transfer from flames in a single tubular turbojet combustor / Leonard Topper

NASA Technical Reports Server (NTRS)

Topper, Leonard

1952-01-01

An experimental investigation of thermal radiation from the flame of a single tubular turbojet-engine combustor to the combustor liner is presented. The effects of combustor inlet-air pressure, air mass flow, and fuel-air ratio on the radiant intensity and the temperature and emissivity of the flame are reported. The total radiation of the "luminous" flames (containing incandescent soot particles) was much greater (4 to 21 times) than the "nonluminous" molecular radiation. The intensity of radiation from the flame increased rapidly with an increase in combustor inlet-air pressure; it was affected to a lesser degree by variations in fuel-air ratio and air mass flow.

Breeding Sex Ratios in Adult Leatherback Turtles (Dermochelys coriacea) May Compensate for Female-Biased Hatchling Sex Ratios

PubMed Central

Stewart, Kelly R.; Dutton, Peter H.

2014-01-01

For vertebrates with temperature-dependent sex determination, primary (or hatchling) sex ratios are often skewed, an issue of particular relevance to concerns over effects of climate change on populations. However, the ratio of breeding males to females, or the operational sex ratio (OSR), is important to understand because it has consequences for population demographics and determines the capacity of a species to persist. The OSR also affects mating behaviors and mate choice, depending on the more abundant sex. For sea turtles, hatchling and juvenile sex ratios are generally female-biased, and with warming nesting beach temperatures, there is concern that populations may become feminized. Our purpose was to evaluate the breeding sex ratio for leatherback turtles at a nesting beach in St. Croix, USVI. In 2010, we sampled nesting females and later sampled their hatchlings as they emerged from nests. Total genomic DNA was extracted and all individuals were genotyped using 6 polymorphic microsatellite markers. We genotyped 662 hatchlings from 58 females, matching 55 females conclusively to their nests. Of the 55, 42 females mated with one male each, 9 mated with 2 males each and 4 mated with at least 3 males each, for a multiple paternity rate of 23.6%. Using GERUD1.0, we reconstructed parental genotypes, identifying 47 different males and 46 females for an estimated breeding sex ratio of 1.02 males for every female. Thus we demonstrate that there are as many actively breeding males as females in this population. Concerns about female-biased adult sex ratios may be premature, and mate choice or competition may play more of a role in sea turtle reproduction than previously thought. We recommend monitoring breeding sex ratios in the future to allow the integration of this demographic parameter in population models. PMID:24505403

High-Temperature Surface Thermometry Technique based on Upconversion Nano-Phosphors

NASA Astrophysics Data System (ADS)

Combs, C.; Clemens, N.; Guo, X.; Song, H.; Zhao, H.; Li, K. K.; Zou, Y. K.; Jiang, H.

2011-11-01

Downconversion thermographic phosphors have been extensively used for high-temperature surface thermometry applications (e.g., aerothermodynamics, turbine blades) where temperature-sensitive paint is not viable. In downconversion techniques the phosphorescence is at longer wavelengths than the excitation source. We are developing a new upconversion thermographic phosphor technique that employs rare-earth-doped ceramics whose phosphorescence exhibit a strong temperature dependence. In the upconversion technique the phosphor is excited with near-IR light and emission is at visible wavelengths; thus, it does not require expensive UV windows and does not suffer from interference from background fluorescence. In this work the upconversion phosphors have been characterized in terms of their intensity, lifetimes and spectral content over a temperature range of 300K to 1500K. The technique has been evaluated for applications of 2D surface temperature measurements by using the total integrated intensity and the ratio of emission in different visible color bands. The results indicate that upconversion phosphor thermometry is a promising technique for making non-contact high-surface temperature measurements with good accuracy. Work supported by NASA under contract NNX11CG89P.

Effects of elevated root zone CO2 and air temperature on photosynthetic gas exchange, nitrate uptake, and total reduced nitrogen content in aeroponically grown lettuce plants.

PubMed

He, Jie; Austin, Paul T; Lee, Sing Kong

2010-09-01

Effects of elevated root zone (RZ) CO(2) and air temperature on photosynthesis, productivity, nitrate (NO(3)(-)), and total reduced nitrogen (N) content in aeroponically grown lettuce plants were studied. Three weeks after transplanting, four different RZ [CO(2)] concentrations [ambient (360 ppm) and elevated concentrations of 2000, 10,000, and 50,000 ppm] were imposed on plants grown at two air temperature regimes of 28 degrees C/22 degrees C (day/night) and 36 degrees C/30 degrees C. Photosynthetic CO(2) assimilation (A) and stomatal conductance (g(s)) increased with increasing photosynthetically active radiation (PAR). When grown at 28 degrees C/22 degrees C, all plants accumulated more biomass than at 36 degrees C/30 degrees C. When measured under a PAR >or=600 micromol m(-2) s(-1), elevated RZ [CO(2)] resulted in significantly higher A, lower g(s), and higher midday leaf relative water content in all plants. Under elevated RZ [CO(2)], the increase of biomass was greater in roots than in shoots, causing a lower shoot/root ratio. The percentage increase in growth under elevated RZ [CO(2)] was greater at 36 degrees C/30 degrees C although the total biomass was higher at 28 degrees C/22 degrees C. NO(3)(-) and total reduced N concentrations of shoot and root were significantly higher in all plants under elevated RZ [CO(2)] than under ambient RZ [CO(2)] of 360 ppm at both temperature regimes. At each RZ [CO(2)], NO(3)(-) and total reduced N concentration of shoots were greater at 28 degrees C/22 degrees C than at 36 degrees C/30 degrees C. At all RZ [CO(2)], roots of plants at 36 degrees C/30 degrees C had significantly higher NO(3)(-) and total reduced N concentrations than at 28 degrees C/22 degrees C. Since increased RZ [CO(2)] caused partial stomatal closure, maximal A and maximal g(s) were negatively correlated, with a unique relationship for each air temperature. However, across all RZ [CO(2)] and temperature treatments, there was a close correlation between maximal A and total shoot reduced N concentration of plants under different RZ [CO(2)], indicating that increased A under elevated RZ [CO(2)] could partially be due to the higher shoot total reduced N.

Temperature affects long-term productivity and quality attributes of day-neutral strawberry for a space life-support system

NASA Astrophysics Data System (ADS)

Massa, Gioia D.; Chase, Elaine; Santini, Judith B.; Mitchell, Cary A.

2015-04-01

Strawberry (Fragaria x ananassa L.) is a promising candidate crop for space life-support systems with desirable sensory quality and health attributes. Day-neutral cultivars such as 'Seascape' are adaptable to a range of photoperiods, including short days that would save considerable energy for crop lighting without reductions in productivity or yield. Since photoperiod and temperature interact to affect strawberry growth and development, several diurnal temperature regimes were tested under a short photoperiod of 10 h per day for effects on yield and quality attributes of 'Seascape' strawberry during production cycles longer than 270 days. The coolest day/night temperature regime, 16°/8 °C, tended to produce smaller numbers of larger fruit than did the intermediate temperature range of 18°/10 °C or the warmest regime, 20°/12 °C, both of which produced similar larger numbers of smaller fruit. The intermediate temperature regime produced the highest total fresh mass of berries over an entire production cycle. Independent experiments examined either organoleptic or physicochemical quality attributes. Organoleptic evaluation indicated that fruit grown under the coolest temperature regime tended to score the highest for both hedonic preference and descriptive evaluation of sensory attributes related to sweetness, texture, aftertaste, and overall approval. The physicochemical quality attributes Brix, pH, and sugar/acid ratio were highest for fruits harvested from the coolest temperature regime and lower for those from the warmer temperature regimes. The cool-regime fruits also were lowest in titratable acidity. The yield parameters fruit number and size oscillated over the course of a production cycle, with a gradual decline in fruit size under all three temperature regimes. Brix and titratable acidity both decreased over time for all three temperature treatments, but sugar/acid ratio remained highest for the cool temperature regime over the entire production period. Periodic rejuvenation or replacement of strawberry propagules may be needed to maintain both quality and quantity of strawberry yield in space.

Trained humans can exercise safely in extreme dry heat when drinking water ad libitum.

PubMed

Nolte, Heinrich W; Noakes, Timothy D; Van Vuuren, Bernard

2011-09-01

Guidelines to establish safe environmental exercise conditions are partly based on thermal prescriptive zones. Yet there are reports of self-paced human athletic performances in extreme heat. Eighteen participants undertook a 25-km route march in a dry bulb temperature reaching 44.3°C. The mean (± s) age of the participants was 26.0 ± 3.7 years. Their mean ad libitum water intake was 1264 ± 229 mL · h(-1). Predicted sweat rate was 1789 ± 267 mL · h(-1). Despite an average body mass loss of 2.73 ± 0.98 kg, plasma osmolality and serum sodium concentration did not change significantly during exercise. Total body water fell 1.47 kg during exercise. However, change in body mass did not accurately predict changes in total body water as a 1:1 ratio. There was a significant relationship (negative slope) between post-exercise serum sodium concentration and changes in both body mass and percent total body water. There was no relationship between percent body mass loss and peak exercise core temperature (39 ± 0.9°C) or exercise time. We conclude that participants maintained plasma osmolality, serum sodium concentration, and safe core temperatures by (1) adopting a pacing strategy, (2) high rates of ad libitum water intake, and (3) by a small reduction in total body water to maintain serum sodium concentration. Our findings support the hypothesis that humans are the mammals with the greatest capacity for exercising in extreme heat.

Determination of electron temperature in a penning discharge by the helium line ratio method

NASA Technical Reports Server (NTRS)

Richardson, R. W.

1975-01-01

The helium line ratio technique was used to determine electron temperatures in a toroidal steady-state Penning discharge operating in helium. Due to the low background pressure, less than .0001 torr, and the low electron density, the corona model is expected to provide a good description of the excitation processes in this discharge. In addition, by varying the Penning discharge anode voltage and background pressure, it is possible to vary the electron temperature as measured by the line ratio technique over a wide range (10 to 100+ eV). These discharge characteristics allow a detailed comparison of electron temperatures measured from different possible line ratios over a wide range of temperatures and under reproducible steady-state conditions. Good agreement is found between temperatures determined from different neutral line ratios, but use of the helium ion line results in a temperature systematically 10 eV high compared to that from the neutral lines.

Thermal Analysis Methods and Basic Heat-Transfer Data for a Turbulent Heating Flight Experiment at Mach 20 (Reentry F)

NASA Technical Reports Server (NTRS)

Howard, Floyd G.

1971-01-01

A heat-transfer experiment was flight conducted on a 5 deg half-angle cone, 396.2 cm (13 ft) in length, as it entered the sensible atmosphere under laminar, transitional, and turbulent boundary-layer conditions at a free-stream Mach number of about 20. Accurate turbulent-heat-transfer data with natural transition were obtained for correlation with theories in regions of simultaneous high Mach number, Reynolds number, enthalpy, and total-to-wall temperature ratio. Temperatures were measured at four depths through the 15.24-mm-thick (0.600-in.) beryllium wall. Experimental heating rates at 20 stations on the cone were determined independently from the outermost temperature measurement and from the temperature measurement at the second depth by a single-thermocouple inverse method and also from the temperature histories at all four depths by an integral method. The thermal data analysis procedure, associated problems, and results are presented herein.

SANS study of deformation and relaxation of a comb-like liquid crystal polymer in the nematic phase

NASA Astrophysics Data System (ADS)

Brûlet, A.; Boué, F.; Keller, P.; Davidson, P.; Strazielle, C.; Cotton, J. P.

1994-06-01

A comb-like liquid crystal polymer is stretched and quenched after a certain time in the nematic phase. The conformation of the deformed chain is determined using small angle neutron scattering (SANS) as a function of the temperature of stretching, the stretching ratio and the duration of the relaxation. The scattering data are well fitted to junction affine and phantom network models. Some data are even well fitted by a totally affine model that we call “ pseudo affine ” because the only parameter, the stretching ratio, is found to be well below the macroscopic stretching ratio. The latter result, never encountered with amorphous polymers, is attributed to the cooperative effects of the nematic phase. We also note that the form factors of the chain in the underformed sample remain similar in the isotropic, nematic and glassy state ; they correspond to a Gaussian chain. The same samples were studied by wide angle X-ray scattering. On one hand, the orientation of the mesogenic groups is found to be parallel or perpendicular to the stretching direction depending on the stretching temperature. This result is discussed as a function of the presence of smectic fluctuations. On the other hand, longer relaxations at constant elongation ratio do not lead to a disorganization of the mesogenic group orientation whereas the polymer chains are partly relaxed.

[Using infrared thermal asymmetry analysis for objective assessment of the lesion of facial nerve function].

PubMed

Liu, Xu-long; Hong, Wen-xue; Song, Jia-lin; Wu, Zhen-ying

2012-03-01

The skin temperature distribution of a healthy human body exhibits a contralateral symmetry. Some lesions of facial nerve function are associated with an alteration of the thermal distribution of the human body. Since the dissipation of heat through the skin occurs for the most part in the form of infrared radiation, infrared thermography is the method of choice to capture the alteration of the infrared thermal distribution. This paper presents a new method of analysis of the thermal asymmetry named effective thermal area ratio, which is a product of two variables. The first variable is mean temperature difference between the specific facial region and its contralateral region. The second variable is a ratio, which is equal to the area of the abnormal region divided by the total area. Using this new method, we performed a controlled trial to assess the facial nerve function of the healthy subjects and the patients with Bell's palsy respectively. The results show: that the mean specificity and sensitivity of this method are 0.90 and 0.87 respectively, improved by 7% and 26% compared with conventional methods. Spearman correlation coefficient between effective thermal area ratio and the degree of facial nerve function is an average of 0.664. Hence, concerning the diagnosis and assessment of facial nerve function, infrared thermography is a powerful tool; while the effective ther mal area ratio is an efficient clinical indicator.

Chemically pretreating slaughterhouse solid waste to increase the efficiency of anaerobic digestion.

PubMed

Flores-Juarez, Cyntia R; Rodríguez-García, Adrián; Cárdenas-Mijangos, Jesús; Montoya-Herrera, Leticia; Godinez Mora-Tovar, Luis A; Bustos-Bustos, Erika; Rodríguez-Valadez, Francisco; Manríquez-Rocha, Juan

2014-10-01

The combined effect of temperature and pretreatment of the substrate on the anaerobic treatment of the organic fraction of slaughterhouse solid waste was studied. The goal of the study was to evaluate the effect of pretreating the waste on the efficiency of anaerobic digestion. The effect was analyzed at two temperature ranges (the psychrophilic and the mesophilic ranges), in order to evaluate the effect of temperature on the performance of the anaerobic digestion process for this residue. The experiments were performed in 6 L batch reactors for 30 days. Two temperature ranges were studied: the psychrophilic range (at room temperature, 18°C average) and the mesophilic range (at 37°C). The waste was pretreated with NaOH before the anaerobic treatment. The result of pretreating with NaOH was a 194% increase in the soluble chemical oxygen demand (COD) with a dose of 0.6 g NaOH per g of volatile suspended solids (VSS). In addition, the soluble chemical oxygen demand/total chemical oxygen demand ratio (sCOD/tCOD) increased from 0.31 to 0.7. For the anaerobic treatment, better results were observed in the mesophilic range, achieving 70.7%, 47% and 47.2% removal efficiencies for tCOD, total solids (TS), and volatile solids (VS), respectively. Copyright © 2014 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

Effects of Cavity Configurations on Flameholding and Performances of Kerosene Fueled Scramjet Combustor

NASA Astrophysics Data System (ADS)

Shi, Deyong; Song, Wenyan; Wang, Yuhang; Wang, Yanhua

2017-08-01

In this work, the effects of cavity flameholder configurations on flameholding and performances of kerosene fueled scramjet combustor were studied experimentally and numerically. For experiments, a directly connected ground facility was used and clean high enthalpy air, with a total temperature of 800 K and a total pressure of 800 Kpa, was provided by an electricity resistance heater. To investigate the effects of cavity configurations on flameholding capacity and reacting-flow characteristics, three different flameholders, one single cavity flameholder and two tandem cavity flameholders, were used in experiments. For the two combustors with tandem cavity flameholders, the location and configurations of its up-stream cavity were same with the single cavity flameholder, and the length-to-depth ratios for down-stream cavities were 9 and 11 respectively. The experimental results showed that stabilize kerosene combustion were achieved for combustor with tandem cavity flameholders mounted, and none for that with single cavity flameholder. The none-reacting and reacting flows of combustor models with tandem cavity flameholders were compared and studied with numerical and experimental results. The results showed that higher combustion efficiencies and pressure recovery ratios were achieved for the combustor with down-stream cavity length-to-depth ratio of 9.

MACS, An Instrument, and a Methodology for Simulations and Global Measurements of the Coronal Electron Temperature and the Solar Wind Velocity on the Solar Corona

NASA Technical Reports Server (NTRS)

Reginald, Nelson L.; Fisher, Richard R. (Technical Monitor)

2000-01-01

The determination of the radial and latitudinal temperature and wind profiles of the solar corona is of great importance in understanding the coronal heating mechanism and the dynamics of coronal expansion. Cram presented the theory for the formation of the K-coronal spectrum and identified two important observations. He observed the existence of temperature sensitive anti-nodes at certain wavelengths in the theoretical K-coronal spectra. The anti-nodes are separated by temperature-insensitive nodes. Remarkably, Cram showed that the wavelengths of the nodes and anti-nodes are almost independent of altitude above the solar limb. Because of these features, Cram suggested that the intensity ratios at two anti-nodes could be used as a diagnostic of the electron temperature in the K-corona. Based on this temperature diagnostic technique prescribed by Cram a slit-based spectroscopic study was performed by Ichimoto et al. on the solar corona in conjunction with the total solar eclipse of 3 Nov 1994 in Putre, Chile to determine the temperature profile of the solar corona. In this thesis Cram's theory has been extended to incorporate the role of the solar wind in the formation of the K-corona, and we have identified both temperature and wind sensitive intensity ratios. The instrument, MACS, for Multi Aperture Coronal Spectrometer, a fiber optic based spectrograph, was designed for global and simultaneous measurement of the thermal electron temperature and the solar wind velocity in the solar corona. The first ever experiment of this nature was conducted in conjunction with the total solar eclipse of 11 Aug 1999 in Elazig, Turkey. In this instrument one end of each of twenty fiber optic tips were positioned in the focal plane of the telescope in such a way that we could observe conditions simultaneously at many different latitudes and two different radial distances in the solar corona. The other ends of the fibers were vertically aligned and placed at the primary focus of the collimating lens of the spectrograph to obtain simultaneous and global spectra on the solar corona. By isolating the K-coronal spectrum from the spectrum recorded by each fiber the temperature and the wind sensitive intensity ratios were calculated to obtain simultaneous and global measurements of the thermal electron temperature and the solar wind velocity. We were successful in obtaining reliable estimates of the coronal temperature at many positions in the corona. This is the first time that simultaneous measurements of coronal temperatures have been obtained at so many points. However due to instrumental scattering encountered during observations, reliable estimates of the wind velocity turned out to be impossible to obtain. Although remedial measures were taken prior to observation, this task proved to be difficult owing to the inability to replicate the conditions expected during an eclipse in the laboratory. The full extent of the instrumental scattering was apparent only when we analyzed the observational sequence. Nevertheless the experience obtained from this very first attempt to simultaneously and globally measure both the wind velocity and the temperature on the solar corona have provided valuable information to conduct any future observations successfully.

Surface loss probability of atomic hydrogen for different electrode cover materials investigated in H₂-Ar low-pressure plasmas

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

Sode, M., E-mail: maik.sode@ipp.mpg.de; Schwarz-Selinger, T.; Jacob, W.

2014-07-07

In an inductively coupled H₂-Ar plasma at a total pressure of 1.5 Pa, the influence of the electrode cover material on selected line intensities of H, H₂, and Ar are determined by optical emission spectroscopy and actinometry for the electrode cover materials stainless steel, copper, tungsten, Macor{sup ®}, and aluminum. Hydrogen dissociation degrees for the considered conditions are determined experimentally from the measured emission intensity ratios. The surface loss probability β{sub H} of atomic hydrogen is correlated with the measured line intensities, and β{sub H} values are determined for the considered materials. Without the knowledge of the atomic hydrogen temperature,more » β{sub H} cannot be determined exactly. However, ratios of β{sub H} values for different surface materials are in first order approximation independent of the atomic hydrogen temperature. Our results show that β{sub H} of copper is equal to the value of stainless steel, β{sub H} of Macor{sup ®} and tungsten is about 2 times smaller and β{sub H} of aluminum about 5 times smaller compared with stainless steel. The latter ratio is in reasonable agreement with literature. The influence of the atomic hydrogen temperature T{sub H} on the absolute value is thoroughly discussed. For our assumption of T{sub H}=600 K, we determine a β{sub H} for stainless steel of 0.39±0.13.« less

Bioactive compounds and encapsulation of Yanang (Tiliacora triandra) leaves.

PubMed

Singthong, Jittra; Oonsivilai, Ratchadaporn; Oonmetta-Aree, Jirawan; Ningsanond, Suwayd

2014-01-01

Yanang (Tiliacora triandra) has been known as vegetable and herbal in northeast Thailand and Lao People's Democratic Republic. Extracts from Yanang leaves contain high amounts of polyphenol constituents possessing antioxidant activity. This work investigated bioactive compounds of Yanang extracts prepared by infusion with water, ethanol and acetone. Furthermore, this paper reports the design of the experimental method for optimization of Yanang encapsulation using three independent variables: the ratio of core material (Yanang), to wall material (gum Arabic), gum Arabic concentration and inlet temperature of spray drying on bioactive compounds stability. The stability of bioactive compounds was evaluated using phenolic compounds, total antioxidant, carotenoids and chlorophyll. The study of the bioactivity of Yanang extracts found that extraction with water was the appropriate application. The study of Yanang encapsulation demonstrated that gum Arabic, as coating agents, protected bioactive compounds of Yanang. Optimized condition for the encapsulation was at the ratio of core to wall {1:4}, in gum Arabic concentration 10% (w/v), and inlet temperature at 160▯C. The results show that the bioactive compounds were mainly affected by the ratio of core to wall material. Besides, moisture content and particle size of encapsulation depend on inlet temperature of spray drying, and gum Arabic concentration, respectively. This optimization reveals that the encapsulation process did not lose the bioactive compounds. Yanang extract with water was the main phenolic compound and showed high antioxidant activities. This study demonstrates the potentials of using spray drying process and optimization for the encapsulation of herbal products.

Simultaneous film and convection cooling of a plate inserted in the exhaust stream of a gas turbine combustor

NASA Technical Reports Server (NTRS)

Marek, C. J.; Juhasz, A. J.

1973-01-01

Data were obtained on a parallel-flow film- and convection-cooled test section placed in the exhaust stream of a rectangular-sector combustor. The combustor was operated at atmospheric pressure and at exhaust temperatures of 589 and 1033 K (600 and 1400 F). The cooling air was at ambient pressure and temperature. Test results indicate that it is better to use combined film and convection cooling rather than either film or convection cooling alone for a fixed total coolant flow. An optimum ratio of film to convection cooling flow rates was determined for the particular geometry tested. The experimental results compared well with calculated results.

Characterization of the mechanical and physical properties of TD-NiCr (Ni-20Cr-2ThO2) alloy sheet

NASA Technical Reports Server (NTRS)

Fritz, L. J.; Koster, W. P.; Taylor, R. E.

1973-01-01

Sheets of TD-NiCr processed using techniques developed to produce uniform material were tested to supply mechanical and physical property data. Two heats each of 0.025 and 0.051 cm thick sheet were tested. Mechanical properties evaluated included tensile, modulus of elasticity, Poisson's Ratio, compression, creep-rupture, creep strength, bearing strength, shear strength, sharp notch and fatigue strength. Test temperatures covered the range from ambient to 1589K. Physical properties were also studied as a function of temperature. The physical properties measured were thermal conductivity, linear thermal expansion, specific heat, total hemispherical emittance, thermal diffusivity, and electrical conductivity.

Continuous wave room temperature external ring cavity quantum cascade laser

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

Revin, D. G., E-mail: d.revin@sheffield.ac.uk; Hemingway, M.; Vaitiekus, D.

2015-06-29

An external ring cavity quantum cascade laser operating at ∼5.2 μm wavelength in a continuous-wave regime at the temperature of 15 °C is demonstrated. Out-coupled continuous-wave optical powers of up to 23 mW are observed for light of one propagation direction with an estimated total intra-cavity optical power flux in excess of 340 mW. The uni-directional regime characterized by the intensity ratio of more than 60 for the light propagating in the opposite directions was achieved. A single emission peak wavelength tuning range of 90 cm{sup −1} is realized by the incorporation of a diffraction grating into the cavity.

Sunflower hulls degradation by co-composting with different nitrogen sources.

PubMed

Conghos, M M; Aguirre, M E; Santamaría, R M

2006-09-01

The decomposition of sunflower hull and its mixtures was examined under mesophilic (M) and thermophilic (T) temperatures during 100 days. Thermophilic conditions were used to define the composting process. Vetch, alfalfa and ammonium nitrate were used as nitrogen co-substrates, in 6 treatments: sunflower hulls alone (C), sunflower hulls plus ammonium nitrate (CN), sunflower hulls plus alfalfa (CA), sunflower hulls plus alfalfa and ammonium nitrate (CAV), sunflower hulls plus vetch (CV), sunflower hulls plus vetch and ammonium nitrate (CVN). Total organic carbon (TOC), oxidizable carbon (OC), dry matter, ashes content, total nitrogen (N), cellulose, hemicellulose, lignin, pH, electrical conductivity and C to N ratio were measured to asses the efficiency of the composting process and to determine the best amendment. Results show that sunflower hulls (Sh) treatment with the organic amendments had a better response than the inorganic ones. This was concluded from the variation in the fiberfractions, the decrease in dry matter and the major decrease in C to N ratio.

Development of a Thiolysis HPLC Method for the Analysis of Procyanidins in Cranberry Products.

PubMed

Gao, Chi; Cunningham, David G; Liu, Haiyan; Khoo, Christina; Gu, Liwei

2018-03-07

The objective of this study was to develop a thiolysis HPLC method to quantify total procyanidins, the ratio of A-type linkages, and A-type procyanidin equivalents in cranberry products. Cysteamine was utilized as a low-odor substitute of toluene-α-thiol for thiolysis depolymerization. A reaction temperature of 70 °C and reaction time of 20 min, in 0.3 M of HCl, were determined to be optimum depolymerization conditions. Thiolytic products of cranberry procyanidins were separated by RP-HPLC and identified using high-resolution mass spectrometry. Standards curves of good linearity were obtained on thiolyzed procyanidin dimer A2 and B2 external standards. The detection and quantification limits, recovery, and precision of this method were validated. The new method was applied to quantitate total procyanidins, average degree of polymerization, ratio of A-type linkages, and A-type procyanidin equivalents in cranberry products. Results showed that the method was suitable for quantitative and qualitative analysis of procyanidins in cranberry products.

Impact of dehydration of purslane on retention of bioactive molecules and antioxidant activity.

PubMed

Shanker, Niharika; Debnath, Sukumar

2015-10-01

Purslane (Portulaca oleracea L.) has several health benefits, such as it reduces risk of CVD, obesity and diabetes. The objective of the study was to investigate the effect of different drying on retention of bioactive molecules, such as omega-3 fatty acids, total phenolic content and antiradical activity of purslane. Five different dehydration methods including microwave (100 MW, 5 min), tray, vacuum, low temperature low humidity, infrared were used at 55-60 °C for 5-7 h for dehydration of purslane. Three solvents, viz. water, ethanol and methanol were used for extraction of bioactive molecules from purslane. Total polyphenol content, antiradical activity and rehydration ratio of the bioactive molecules were determined. Results revealed that total PUFA, α-linolenic acid (ALA), total polyphenol content and antiradical activity were found to retain in the dried purslane in the range of (47.9-59.9 %), (42.5-50 %), (188-408GAE/100 g) and (33.0-88.8 mg/100 g) respectively. The highest values of ALA, total polyphenol content and antiradical activity were found to obtain in the vacuum dried sample. Rehydration ratio was found in the range of 3.2-4.3 and vacuum dried purslane showed maximum rehydration. It could be concluded that vacuum dehydration of purslane is an effective method for retention of bioactive molecules and good rehydration behaviour of dried purslane.

Effects of stress ratio on the temperature-dependent high-cycle fatigue properties of alloy steels

NASA Astrophysics Data System (ADS)

Lü, Zhi-yang; Wan, Ao-shuang; Xiong, Jun-jiang; Li, Kuang; Liu, Jian-zhong

2016-12-01

This paper addresses the effects of stress ratio on the temperature-dependent high-cycle fatigue (HCF) properties of alloy steels 2CrMo and 9CrCo, which suffer from substantial vibrational loading at small stress amplitude, high stress ratio, and high frequency in the high-temperature environments in which they function as blade and rotor spindle materials in advanced gas or steam turbine engines. Fatigue tests were performed on alloy steels 2CrMo and 9CrCo subjected to constant-amplitude loading at four stress ratios and at four and three temperatures, respectively, to determine their temperature-dependent HCF properties. The interaction mechanisms between high temperature and stress ratio were deduced and compared with each other on the basis of the results of fractographic analysis. A phenomenological model was developed to evaluate the effects of stress ratio on the temperature-dependent HCF properties of alloy steels 2CrMo and 9CrCo. Good correlation was achieved between the predictions and actual experiments, demonstrating the practical and effective use of the proposed method.

An Examination of Two Pathways to Tropical Cyclogenesis Occurring in Idealized Simulations with a Cloud-Resolving Numerical Model

DTIC Science & Technology

2013-06-21

potential temperature (Tripoli and Cotton , 1981), total wa- ter mixing ratio and cloud microphysics. The microphysics scheme has categories for cloud droplets...components, with diurnal variation, are both activated when the radiation scheme is included. A simpler scheme developed by Chen and Cotton (1987) is an...radiation. Additionally, one more simula- tion, Experiment 17, was conducted using the Chen– Cotton radiation scheme instead of the Harrington scheme

Nucleation and growth of single layer graphene on electrodeposited Cu by cold wall chemical vapor deposition

NASA Astrophysics Data System (ADS)

Das, Shantanu; Drucker, Jeff

2017-03-01

The nucleation density and average size of graphene crystallites grown using cold wall chemical vapor deposition (CVD) on 4 μm thick Cu films electrodeposited on W substrates can be tuned by varying growth parameters. Growth at a fixed substrate temperature of 1000 °C and total pressure of 700 Torr using Ar, H2 and CH4 mixtures enabled the contribution of total flow rate, CH4:H2 ratio and dilution of the CH4/H2 mixture by Ar to be identified. The largest variation in nucleation density was obtained by varying the CH4:H2 ratio. The observed morphological changes are analogous to those that would be expected if the deposition rate were varied at fixed substrate temperature for physical deposition using thermal evaporation. The graphene crystallite boundary morphology progresses from irregular/jagged through convex hexagonal to regular hexagonal as the effective C deposition rate decreases. This observation suggests that edge diffusion of C atoms along the crystallite boundaries, in addition to H2 etching, may contribute to shape evolution of the graphene crystallites. These results demonstrate that graphene grown using cold wall CVD follows a nucleation and growth mechanism similar to hot wall CVD. As a consequence, the vast knowledge base relevant to hot wall CVD may be exploited for graphene synthesis by the industrially preferable cold wall method.

High-level direct-dynamics variational transition state theory calculations including multidimensional tunneling of the thermal rate constants, branching ratios, and kinetic isotope effects of the hydrogen abstraction reactions from methanol by atomic hydrogen.

PubMed

Meana-Pañeda, Rubén; Truhlar, Donald G; Fernández-Ramos, Antonio

2011-03-07

We report a detailed theoretical study of the hydrogen abstraction reaction from methanol by atomic hydrogen. The study includes the analysis of thermal rate constants, branching ratios, and kinetic isotope effects. Specifically, we have performed high-level computations at the MC3BB level together with direct dynamics calculations by canonical variational transition state theory (CVT) with the microcanonically optimized multidimensional tunneling (μOMT) transmission coefficient (CVT/μOMT) to study both the CH(3)OH+H→CH(2)OH+H(2) (R1) reaction and the CH(3)OH+H→CH(3)O+H(2) (R2) reaction. The CVT/μOMT calculations show that reaction R1 dominates in the whole range 298≤T (K)≤2500 and that anharmonic effects on the torsional mode about the C-O bond are important, mainly at high temperatures. The activation energy for the total reaction sum of R1 and R2 reactions changes substantially with temperature and, therefore, the use of straight-line Arrhenius plots is not valid. We recommend the use of new expressions for the total R1 + R2 reaction and for the R1 and R2 individual reactions. © 2011 American Institute of Physics.

Influence of temperature on rate of uptake and subsequent horizontal transfer of [14C]fipronil by eastern subterranean termites (Isoptera: Rhinotermitidae).

PubMed

Spomer, Neil A; Kamble, Shripat T; Warriner, Richard A; Davis, Robert W

2008-06-01

The effect of temperature on [14C]fipronil uptake and transfer from donor (D) to recipient (R) Reticulitermes flavipes (Kollar) (Isoptera: Rhinotermitidae) workers was evaluated. Test chambers used in the fipronil uptake study were constructed from petri dishes containing autoclaved soil treated with 1 ppm [14C]fipronil (1.14 microCi of total radioactivity per petri dish), distilled water, and R. flavipes workers. Test chambers were held in environmental growth chambers preset at 12, 17, 22, 27, and 32 degrees C. For the fipronil transfer study, donor termites stained with Nile blue-A were exposed to soil treated with 1 ppm [14C]fipronil for 2 h. Donors were then combined with unexposed recipient termite workers at either 1D:5R, 1D:10R, or 1D:20R ratios. Test chambers consisted of a nest and feeding chamber connected by a piece of polyethylene tube and held in growth chambers at 12, 17, 22, 27, and 32 degrees C. Worker termites were sampled over time and the amount of [14C]fipronil present was measured by scintillation counting. Some degree of uptake and transfer occurred at all temperatures and ratios in this study. The highest level of uptake occurred by termites held at 22-32 degrees C, followed decreasingly by 17 and 12 degrees C. Maximum transfer of [14C]fipronil occurred at the higher ratios (1:5 > 1:10 > 1:20) of donors to recipients. Data presented in this study suggest that temperature is one of the key factors affecting the rate of uptake and subsequent horizontal transfer of [14C]fipronil in subterranean termites.

Experimentally Determined Site-Specific Reactivity of the Gas-Phase OH and Cl + i-Butanol Reactions Between 251 and 340 K.

PubMed

McGillen, Max R; Tyndall, Geoffrey S; Orlando, John J; Pimentel, Andre S; Medeiros, Diogo J; Burkholder, James B

2016-12-22

Product branching ratios for the gas-phase reactions of i-butanol, (CH 3 ) 2 CHCH 2 OH, with OH radicals (251, 294, and 340 K) and Cl atoms (294 K) were quantified in an environmental chamber study and used to interpret i-butanol site-specific reactivity. i-Butyraldehyde, acetone, acetaldehyde, and formaldehyde were observed as major stable end products in both reaction systems with carbon mass balance indistinguishable from unity. Product branching ratios for OH oxidation were found to be temperature-dependent with the α, β, and γ channels changing from 34 ± 6 to 47 ± 1%, from 58 ± 6 to 37 ± 9%, and from 8 ± 1 to 16 ± 4%, respectively, between 251 and 340 K. Recommended temperature-dependent site-specific modified Arrhenius expressions for the OH reaction rate coefficient are (cm 3 molecule -1 s -1 ): k α (T) = 8.64 × 10 -18 × T 1.91 exp(666/T); k β (T) = 5.15 × 10 -19 × T 2.04 exp(1304/T); k γ (T) = 3.20 × 10 -17 × T 1.78 exp(107/T); k OH (T) = 2.10 × 10 -18 × T 2 exp(-23/T), where k Total (T) = k α (T) + k β (T) + k γ (T) + k OH (T). The expressions were constrained using the product branching ratios measured in this study and previous total phenomenological rate coefficient measurements. The site-specific expressions compare reasonably well with recent theoretical work. It is shown that use of i-butanol would result in acetone as the dominant degradation product under most atmospheric conditions.

Testing the variability of the proton-to-electron mass ratio from observations of methanol in the dark cloud core L1498

NASA Astrophysics Data System (ADS)

Daprà, M.; Henkel, C.; Levshakov, S. A.; Menten, K. M.; Muller, S.; Bethlem, H. L.; Leurini, S.; Lapinov, A. V.; Ubachs, W.

2017-12-01

The dependence of the proton-to-electron mass ratio, μ, on the local matter density was investigated using methanol emission in the dense dark cloud core L1498. Towards two different positions in L1498, five methanol transitions were detected and an extra line was tentatively detected at a lower confidence level in one of the positions. The observed centroid frequencies were then compared with their rest-frame frequencies derived from least-squares fitting to a large data set. Systematic effects, as the underlying methanol hyperfine structure and the Doppler tracking of the telescope, were investigated and their effects were included in the total error budget. The comparison between the observations and the rest-frame frequencies constrains potential μ variation at the level of Δμ/μ < 6 × 10-8, at a 3σ confidence level. For the dark cloud, we determine a total CH3OH (A+E) beam averaged column density of ∼3-4 × 1012 cm-2 (within roughly a factor of two), an E- to A-type methanol column density ratio of N(A-CH3OH)/N(E-CH3OH) ∼1.00 ± 0.15, a density of n(H2) = 3 × 105 cm-3 (again within a factor of two) and a kinetic temperature of Tkin = 6 ± 1 K. In a kinetic model including the line intensities observed for the methanol lines, the n(H2) density is higher and the temperature is lower than that derived in previous studies based on different molecular species; the intensity of the 10 → 1-1 E line strength is not well reproduced.

Ultra clean burner for an AMTEC system suitable for hybrid electric vehicles

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

Mital, R.; Sievers, R.K.; Hunt, T.K.

1997-12-31

High power Alkali Metal Thermal to Electric Converter (AMTEC) systems have the potential to make the hybrid electric vehicle (HEV) program a success by meeting the challenging standards put forth by the EPA for the automobile industry. The premise of the whole concept of using AMTEC cells, as discussed by Hunt et al. (1995), for power generation in HEV`s is based on the utilization of a high efficiency external combustion system. The key requirement being a burner which will produce extremely low quantities of carbon monoxide and oxides of nitrogen, emit minimal amounts of hydrocarbon, will have high radiative andmore » convective efficiencies and at least a 4:1 turndown ratio. This work presents one such burner which has the potential to meet all of these demands and more. After investigation of a number of burners, including, metal fiber, ported metal, ceramic fiber and ported ceramic, it is believed that cellular ceramic burners will be the best candidates for integration with AMTEC cells for a high power system suitable for hybrid electric vehicles. A detailed study which includes the operating range, radiation efficiency, total heat transfer efficiency, spectral intensity, exit gas temperature and pollutant emission indices measurement has been carried out on circular and square shaped burners. Total heat transfer efficiencies as high as 65--70% have been measured using a water calorimeter. With efficient recuperation, a burner/recuperator efficiency of 80% at peak power and 90% at peak efficiency operating points are conceivable with this burner. Establishment of combustion within the porous matrix leads to low peak temperatures and hence lower NO{sub x}. The emission indices of CO and HC are also quite low. The stability range measurements show a 6:1 turndown ratio at an equivalence ratio of 0.9.« less

A hail climatology in Mongolia

NASA Astrophysics Data System (ADS)

Lkhamjav, Jambajamts; Jin, Han-Gyul; Lee, Hyunho; Baik, Jong-Jin

2017-11-01

The temporal and spatial characteristics of hail frequency in Mongolia are examined using the hail observation data from 61 meteorological observatories for 1984-2013. The annual number of hail days averaged over all observatories and the entire period is 0.74. It exhibits a decreasing trend, particularly since 1993 with a rate of decrease of 0.214 per decade. Hail occurrence is concentrated in summer, with 72% of the total hail days occurring in June, July, and August. Moreover, hail occurrence is concentrated in the afternoon and early evening, with 89% of the total hail events occurring between 1200 and 2100 local standard time (LST). Spatially, observatories where relatively frequent hail events are observed are concentrated in the north central region where almost all of the land is mountainous or covered by grassland, whereas relatively less frequent hail events are observed in the southern desert region. The relationship between hail frequency and thermodynamic factors including the convective available potential energy (CAPE), the temperature lapse rate between 700 and 500 hPa, the water vapor mixing ratio averaged over the lowest 100 hPa layer, and the freezing-level height is examined using the ERA-Interim reanalysis data. It is found that in summer, CAPE and the low-level water vapor mixing ratio are larger on hail days than on all days, but there is no clear relationship between hail frequency and the 700-500 hPa temperature lapse rate. It is also found that annually, CAPE and the low-level water vapor mixing ratio decrease, while the freezing-level height increases, which seems to be responsible for the annually decreasing trend of hail frequency in Mongolia.

Experimental study on physiological responses and thermal comfort under various ambient temperatures.

PubMed

Yao, Ye; Lian, Zhiwei; Liu, Weiwei; Shen, Qi

2008-01-28

This study mainly explored the thermal comfort from the perspective of physiology. Three physiological parameters, including skin temperature (local and mean), electrocardiograph (ECG) and electroencephalogram (EEG), were investigated to see how they responded to the ambient temperature and how they were related to the thermal comfort sensation. A total of four ambient temperatures (21 degrees C, 24 degrees C, 26 degrees C and 29 degrees C) were created, while the other thermal conditions including the air velocity (about 0.05+/-0.01 m/s) and the air humidity (about 60+/-5 m/s) were kept as stable as possible throughout the experiments. Twenty healthy students were tested with questionnaire investigation under those thermal environments. The statistical analysis shows that the skin temperature (local and mean), the ratio of LF(norm) to HF(norm) of ECG and the global relative power of the different EEG frequency bands will be sensitive to the ambient temperatures and the thermal sensations of the subjects. It is suggested that the three physiological parameters should be considered all together in the future study of thermal comfort.

Targeted temperature management at 33°C versus 36°C after cardiac arrest.

PubMed

Nielsen, Niklas; Wetterslev, Jørn; Cronberg, Tobias; Erlinge, David; Gasche, Yvan; Hassager, Christian; Horn, Janneke; Hovdenes, Jan; Kjaergaard, Jesper; Kuiper, Michael; Pellis, Tommaso; Stammet, Pascal; Wanscher, Michael; Wise, Matt P; Åneman, Anders; Al-Subaie, Nawaf; Boesgaard, Søren; Bro-Jeppesen, John; Brunetti, Iole; Bugge, Jan Frederik; Hingston, Christopher D; Juffermans, Nicole P; Koopmans, Matty; Køber, Lars; Langørgen, Jørund; Lilja, Gisela; Møller, Jacob Eifer; Rundgren, Malin; Rylander, Christian; Smid, Ondrej; Werer, Christophe; Winkel, Per; Friberg, Hans

2013-12-05

Unconscious survivors of out-of-hospital cardiac arrest have a high risk of death or poor neurologic function. Therapeutic hypothermia is recommended by international guidelines, but the supporting evidence is limited, and the target temperature associated with the best outcome is unknown. Our objective was to compare two target temperatures, both intended to prevent fever. In an international trial, we randomly assigned 950 unconscious adults after out-of-hospital cardiac arrest of presumed cardiac cause to targeted temperature management at either 33°C or 36°C. The primary outcome was all-cause mortality through the end of the trial. Secondary outcomes included a composite of poor neurologic function or death at 180 days, as evaluated with the Cerebral Performance Category (CPC) scale and the modified Rankin scale. In total, 939 patients were included in the primary analysis. At the end of the trial, 50% of the patients in the 33°C group (235 of 473 patients) had died, as compared with 48% of the patients in the 36°C group (225 of 466 patients) (hazard ratio with a temperature of 33°C, 1.06; 95% confidence interval [CI], 0.89 to 1.28; P=0.51). At the 180-day follow-up, 54% of the patients in the 33°C group had died or had poor neurologic function according to the CPC, as compared with 52% of patients in the 36°C group (risk ratio, 1.02; 95% CI, 0.88 to 1.16; P=0.78). In the analysis using the modified Rankin scale, the comparable rate was 52% in both groups (risk ratio, 1.01; 95% CI, 0.89 to 1.14; P=0.87). The results of analyses adjusted for known prognostic factors were similar. In unconscious survivors of out-of-hospital cardiac arrest of presumed cardiac cause, hypothermia at a targeted temperature of 33°C did not confer a benefit as compared with a targeted temperature of 36°C. (Funded by the Swedish Heart-Lung Foundation and others; TTM ClinicalTrials.gov number, NCT01020916.).

Annealing temperature dependence of magnetoimpedance effect in electrodeposited [Ni80fe20/Cu]3 multilayers

NASA Astrophysics Data System (ADS)

Maulana, Frendi; Eko Prastyo, W.; Nuryani; Purnama, B.

2017-11-01

We have conducted an experiment of magnetoimpedance with a variation of annealing temperature of [Ni80Fe20/Cu)]3 multilayers. The multilayer is electrodeposited on Cu-PCB substrate. Magnetoimpedance effect is impedance measure on account of external magnetic field. The found MI (magnetoimpedance) ratio is 7,63 % (without annealing) and 4,75 % (using annealing) of 100 ºC. We find that MI ratio depends on to annealing temperature and current frequence. MI ratio decreases due to rising temperature and identified increase due to the frequency. The highest MI ratio is on a sample without annealing temperature and measurement at 100 kHz frequence.

Reconstruction of the temperature field for inverse ultrasound hyperthermia calculations at a muscle/bone interface.

PubMed

Liauh, Chihng-Tsung; Shih, Tzu-Ching; Huang, Huang-Wen; Lin, Win-Li

2004-02-01

An inverse algorithm with Tikhonov regularization of order zero has been used to estimate the intensity ratios of the reflected longitudinal wave to the incident longitudinal wave and that of the refracted shear wave to the total transmitted wave into bone in calculating the absorbed power field and then to reconstruct the temperature distribution in muscle and bone regions based on a limited number of temperature measurements during simulated ultrasound hyperthermia. The effects of the number of temperature sensors are investigated, as is the amount of noise superimposed on the temperature measurements, and the effects of the optimal sensor location on the performance of the inverse algorithm. Results show that noisy input data degrades the performance of this inverse algorithm, especially when the number of temperature sensors is small. Results are also presented demonstrating an improvement in the accuracy of the temperature estimates by employing an optimal value of the regularization parameter. Based on the analysis of singular-value decomposition, the optimal sensor position in a case utilizing only one temperature sensor can be determined to make the inverse algorithm converge to the true solution.

Volatiles and energy released by Puracé volcano

NASA Astrophysics Data System (ADS)

Maldonado, Luisa Fernanda Meza; Inguaggiato, Salvatore; Jaramillo, Marco Tulio; Valencia, Gustavo Garzón; Mazot, Agnes

2017-12-01

Total CO2 output of Puracé volcano (Colombia) was estimated on the basis of fluids discharged by fumaroles, soil gases, and dissolved carbon species in the aquifer. The soil CO2 emission was computed from a field survey of 512 points of CO2 soil flux measurements at the main degassing areas of Puracé volcano. The CO2 flux from Puracé's plume was estimated using an indirect method, that used the SO2 plume flux and CO2/SO2 ratio of the main high temperature fumarole. The total output of CO2 was estimated at ≅ 1500 t/day. The main contribution of CO2 comes from the plume (summit degassing) and from soil degassing that emit 673 and 812 t/day, respectively. The contributions of summit and soil degassing areas are comparable, indicating an intermediate degassing style partitioned between closed and open conduit systems. The estimated water vapor discharge (as derived from the chemical composition of the fumaroles, the H2O/CO2 ratio, and the SO2 plume flux) allowed calculation of the total thermal energy (fumarolic, soil degassing, and aquifer) released from the Puracé volcanic system. This was 360 MW.

The effect of circumferential distortion on fan performance at two levels of blade loading

NASA Technical Reports Server (NTRS)

Hartmann, M. J.; Sanger, N. L.

1975-01-01

Single stage fans designed for two levels of pressure ratio or blade loading were subjected to screen-induced circumferential distortions of 90-degree extent. Both fan rotors were designed for a blade tip speed of 425 m/sec, blade solidity of 1.3 and a hub-to-tip radius ratio of 0.5. Circumferential measurements of total pressure, temperature, static pressure, and flow angle were obtained at the hub, mean and tip radii at five axial stations. Rotor loading level did not appear to have a significant influence on rotor response to distorted flow. Losses in overall pressure ratio due to distortion were most severe in the stator hub region of the more highly loaded stage. At the near stall operating condition tip and hub regions of (either) rotor demonstrated different response characteristics to the distorted flow. No effect of loading was apparent on interactions between rotor and upstream distorted flow fields.

Microwave Thermal Hydrolysis Of Sewage Sludge As A Pretreatment Stage For Anaerobic Digestion

NASA Astrophysics Data System (ADS)

Qiao, W.; Wang, W.; Xun, R.

2008-02-01

This article focuses on the effects of microwave thermal hydrolysis on sewage sludge anaerobic digestion. Volatile suspended solid (VSS) and COD solubilization of treated sludge were investigated. It was found that the microwave hydrolysis provided a rapid and efficient process to release organics from sludge. The increase of organic dissolution ratio was not obvious when holding time was over 5 min. The effect of the VSS solubilization was mainly dependent on temperature. The highest value of VSS dissolving ratio, 36.4%, was obtained at 170 °C for 30 min. COD dissolving ratio was about 25% at 170 °C. BMP test of excess sludge and mixture of primary and excess sludge proved the increase of methane production. Total biogas production of microwave treated mixture sludge increased by 12.9% to 20.2% over control after 30 days digestion. For excess sludge, biogas production was 11.1% to 25.9% higher than untreated sludge.

Inoculation with a psychrotrophic-thermophilic complex microbial agent accelerates onset and promotes maturity of dairy manure-rice straw composting under cold climate conditions.

PubMed

Gou, Changlong; Wang, Yuqiong; Zhang, Xiqing; Lou, Yujie; Gao, Yunhang

2017-11-01

The objective was to determine the effects of psychrotrophic-thermophilic complex microbial agent (PTCMA) comprised of a psychrotrophic bacterium consortium (PBC) and a thermophilic cellulolytic fungi consortium (TCFC), on composting in a cold climate. Mixtures of dairy manure and rice straw were inoculated with PTCMA, PBC, TCFC and sterile water (control) and composted at an initial ambient temperatures of -2 to 5°C. In compost piles inoculated with PBC or PTCMA, temperatures reached the thermophilic phase (>55°C) faster (8-11d) than piles inoculated with TCFC or control. Furthermore, compost inoculated with TCFC or PTCMA had greater decreases in total organic carbon and carbon-to-nitrogen ratios, as well as significant increases in total nitrogen, degradation of cellulose and lignin and germination index than PBC inoculation or Control compost. Consequently, inoculation with both (i.e. PTCMA) accelerated the onset and promoted maturity of composting under cold-climate conditions. Copyright © 2017 Elsevier Ltd. All rights reserved.

Quantitative effects of composting state variables on C/N ratio through GA-aided multivariate analysis.

PubMed

Sun, Wei; Huang, Guo H; Zeng, Guangming; Qin, Xiaosheng; Yu, Hui

2011-03-01

It is widely known that variation of the C/N ratio is dependent on many state variables during composting processes. This study attempted to develop a genetic algorithm aided stepwise cluster analysis (GASCA) method to describe the nonlinear relationships between the selected state variables and the C/N ratio in food waste composting. The experimental data from six bench-scale composting reactors were used to demonstrate the applicability of GASCA. Within the GASCA framework, GA searched optimal sets of both specified state variables and SCA's internal parameters; SCA established statistical nonlinear relationships between state variables and the C/N ratio; to avoid unnecessary and time-consuming calculation, a proxy table was introduced to save around 70% computational efforts. The obtained GASCA cluster trees had smaller sizes and higher prediction accuracy than the conventional SCA trees. Based on the optimal GASCA tree, the effects of the GA-selected state variables on the C/N ratio were ranged in a descending order as: NH₄+-N concentration>Moisture content>Ash Content>Mean Temperature>Mesophilic bacteria biomass. Such a rank implied that the variation of ammonium nitrogen concentration, the associated temperature and the moisture conditions, the total loss of both organic matters and available mineral constituents, and the mesophilic bacteria activity, were critical factors affecting the C/N ratio during the investigated food waste composting. This first application of GASCA to composting modelling indicated that more direct search algorithms could be coupled with SCA or other multivariate analysis methods to analyze complicated relationships during composting and many other environmental processes. Copyright © 2010 Elsevier B.V. All rights reserved.

The Charge State of Polycyclic Aromatic Hydrocarbons across a Reflection Nebula, an H II Region, and a Planetary Nebula

NASA Astrophysics Data System (ADS)

Boersma, C.; Bregman, J.; Allamandola, L. J.

2018-05-01

Low-resolution Spitzer-IRS spectral map data of a reflection nebula (NGC 7023), H II region (M17), and planetary nebula (NGC 40), totaling 1417 spectra, are analyzed using the data and tools available through the NASA Ames PAH IR Spectroscopic Database. The polycyclic aromatic hydrocarbon (PAH) emission is broken down into PAH charge and size subclass contributions using a database-fitting approach. The resulting charge breakdown results are combined with those derived using the traditional PAH band strength ratio approach, which interprets particular PAH band strength ratios as proxies for PAH charge. Here the 6.2/11.2 μm PAH band strength ratio is successfully calibrated against its database equivalent: the {n}PAH}+}/{n}PAH}0} ratio. In turn, this ratio is converted into the PAH ionization parameter, which relates it to the strength of the radiation field, gas temperature, and electron density. Population diagrams are used to derive the {{{H}}}2 density and temperature. The bifurcated plot of the 8.6 versus 11.2 μm PAH band strength for the northwest photo dissociation region in NGC 7023 is shown to be a robust diagnostic template for the {n}PAH}+}/{n}PAH}0} ratio in all three objects. Template spectra for the PAH charge and size subclasses are determined for each object and shown to favorably compare. Using the determined template spectra from NGC 7023 to fit the emission in all three objects yields, upon inspection of the Structure SIMilarity maps, satisfactory results. The choice of extinction curve proves to be critical. Concluding, the distinctly different astronomical environments of a reflection nebula, H II region, and planetary nebula are reflected in their PAH emission spectra.

Effects of dietary DL-2-hydroxy-4(methylthio)butanoic acid supplementation on growth performance, indices of ascites syndrome, and antioxidant capacity of broilers reared at low ambient temperature

NASA Astrophysics Data System (ADS)

Yang, G. L.; Zhang, K. Y.; Ding, X. M.; Zheng, P.; Luo, Y. H.; Bai, S. P.; Wang, J. P.; Xuan, Y.; Su, Z. W.; Zeng, Q. F.

2016-08-01

This study examined the effects of dietary DL-2-hydroxy-4(methylthio)butanoic acid (DL-HMTBA) supplementation on growth performance, antioxidant capacity, and ascites syndrome (AS) in broilers reared at low ambient temperature (LAT) from 7 to 28 days of age. Eight hundred 7-day-old broilers were randomly assigned to two ambient temperatures (LAT and normal ambient temperature [NAT]), four supplemental DL-HMTBA levels (0.17, 0.34, 0.51, and 0.68 %) of the basal diet in a 2 × 4 factorial arrangement (ten replicate pens; ten birds/pen). LAT and NAT indicate temperatures of 12-14 and 24-26 °C in two chambers, respectively, and broilers were reared at these temperatures from 7 to 28 days of age. LAT significantly decreased body weight gain ( P < 0.001), serum glutathione (GSH) content (day 14, P = 0.02; day 28, P = 0.045), glutathione peroxidase (GSH-Px) activity, and total antioxidant capacity (T-AOC) at 21 days ( P = 0.001, 0.015) and 28 days ( P = 0.017, 0.010) and increased feed conversion ratio (FCR) ( P < 0.001), serum malondialdehyde (day 21, P = 0.000) and protein carbonyl Level (day 14, P = 0.003; day 21, P = 0.035). As for incidence of AS, there were significant effects of LAT on red blood cell (RBC) count ( P < 0.05), hematocrit (HCT) ( P < 0.05), and the right to total ventricular weight ratio (RV/TV) at 21 days ( P = 0.012) and 28 days ( P = 0.046). Supplementation of DL-HMTBA markedly decreased RV/TV at day 28 ( P = 0.021), RBC (day 21, P = 0.008), HCT (day 21, P < 0.001), mean cell hemoglobin (day 14, P = 0.035; day 21, P = 0.003), and serum protein carbonyl level (day 21, P = 0.009), while significantly increased serum GSH content (day 14, P = 0.022; day 28, P = 0.001), SOD and GSH-Px activities at 21 days of age ( P < 0.001 and P = 0.037). The optimal supplemental DL-HMTBA levels in basal diet of broilers aged from 7 to 28 days under low or normal temperatures were similar, so the authors recommended supplemental of DL-HMTBA level was 0.46 %.

A simple and rapid infrared-assisted self enzymolysis extraction method for total flavonoid aglycones extraction from Scutellariae Radix and mechanism exploration.

PubMed

Wang, Liping; Duan, Haotian; Jiang, Jiebing; Long, Jiakun; Yu, Yingjia; Chen, Guiliang; Duan, Gengli

2017-09-01

A new, simple, and fast infrared-assisted self enzymolysis extraction (IRASEE) approach for the extraction of total flavonoid aglycones (TFA) mainly including baicalein, wogonin, and oroxylin A from Scutellariae Radix is presented to enhance extraction yield. Extraction enzymolysis temperature, enzymolysis liquid-to-solid ratio, enzymolysis pH, enzymolysis time and infrared power, the factors affecting IRASEE procedure, were investigated in a newly designed, temperature-controlled infrared-assisted extraction (TC-IRAE) system to acquire the optimum analysis conditions. The results illustrated that IRASEE possessed great advantages in terms of efficiency and time compared with other conventional extraction techniques. Furthermore, the mechanism of IRASEE was preliminarily explored by observing the microscopic change of the samples surface structures, studying the main chemical compositions change of the samples before and after extraction and investigating the kinetics and thermodynamics at three temperature levels during the IRASEE process. These findings revealed that IRASEE can destroy the surface microstructures to accelerate the mass transfer and reduce the activation energy to intensify the chemical process. This integrative study presents a simple, rapid, efficient, and environmental IRASEE method for TFA extraction which has promising prospects for other similar herbal medicines. Graphical Abstract ᅟ.

On the thermodynamics of waste heat recovery from internal combustion engine exhaust gas

NASA Astrophysics Data System (ADS)

Meisner, G. P.

2013-03-01

The ideal internal combustion (IC) engine (Otto Cycle) efficiency ηIC = 1-(1/r)(γ - 1) is only a function of engine compression ratio r =Vmax/Vmin and exhaust gas specific heat ratio γ = cP/cV. Typically r = 8, γ = 1.4, and ηIC = 56%. Unlike the Carnot Cycle where ηCarnot = 1-(TC/TH) for a heat engine operating between hot and cold heat reservoirs at TH and TC, respectively, ηIC is not a function of the exhaust gas temperature. Instead, the exhaust gas temperature depends only on the intake gas temperature (ambient), r, γ, cV, and the combustion energy. The ejected exhaust gas heat is thermally decoupled from the IC engine and conveyed via the exhaust system (manifold, pipe, muffler, etc.) to ambient, and the exhaust system is simply a heat engine that does no useful work. The maximum fraction of fuel energy that can be extracted from the exhaust gas stream as useful work is (1-ηIC) × ηCarnot = 32% for TH = 850 K (exhaust) and TC = 370 K (coolant). This waste heat can be recovered using a heat engine such as a thermoelectric generator (TEG) with ηTEG> 0 in the exhaust system. A combined IC engine and TEG system can generate net useful work from the exhaust gas waste heat with efficiency ηWH = (1-ηIC) × ηCarnot ×ηTEG , and this will increase the overall fuel efficiency of the total system. Recent improvements in TEGs yield ηTEG values approaching 15% giving a potential total waste heat conversion efficiency of ηWH = 4.6%, which translates into a fuel economy improvement approaching 5%. This work is supported by the US DOE under DE-EE0005432.

Observations on the reproductive and larval biology of Blennius pavo (Pisces: Teleostei)

NASA Astrophysics Data System (ADS)

Westernhagen, H.

1983-09-01

Social behaviour and spawning of adult Blennius pavo kept in the laboratory are described. Eggs are deposited in batches on the walls of artificial spawning places (PVC pipes). One male guards and tends the eggs of different females in one spawning place. Larval hatching occurs in groups according to oviposition. Minimum incubation temperature is around 14 15°C. Larval survival in 1-1 rearing jars is not related to larval total length but to density of larval stock. An experimental population of laboratory reared juvenile and adolescent B. pavo displays a male to female ratio of 1:1.4. Factors possibly influencing the sex ratio of this littoral fish are discussed in view of the situation in its natural environment.

Magneto-impedance in Multilayered [Ni80Fe20/Cu]4 with modification of the line-length pattern on Cu printed circuit board

NASA Astrophysics Data System (ADS)

Eko Prastyo, Wahyu; Maulana, F.; Nuryani, N.; Purnama, B.

2017-11-01

Magneto-impedance of multilayer [Ni80Fe20/Cu]4 on Cu PCB substrate has successfully studied. To enhance the magneto-impedance we modify the geometry the Cu PCB substrate. The multilayer is made by electro-deposition with Pt (Platinum) as elctrodes. Electro-deposition is made at room temperature. Magneto-impedance total is evaluated under the external magnetic field. The results shows that magneto-impedance curve is symmetry. The difference of line-length result in the difference of the magneto-impedance. The samples is with the longest line-length has the largest magneto-impedance ratio. The homogeneity of the samples is on account estimated the increase magneto-impedance ratio.

Interactions between pre-main-sequence objects and molecular clouds. I. Elias 1-12

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

Levreault, R.M.

1983-02-15

Line profiles of the CO( J = 1 ..-->.. 0), CO( J = 2 ..-->.. 1), /sup 13/CO( J = 1 ..-->.. 0), /sup 13/CO( J = 2 ..-->.. 1), HCO/sup +/( J = 1 ..-->.. 0), and HCO/sup +/( J = 3 ..-->.. 2) transitions have been observed toward the FU Orionis star Elias 1-12. The CO profiles show broad asymmetric line wings, while the /sup 13/CO and HCO/sup +/ profiles show weaker wings. The ratios of various transitions in the line wings are a powerful probe of the physical conditions in the kinematically disturbed gas that produces themore » broad wings. The disturbed gas extends over 0.3 pc and has a total mass of 1.2 M/sub sun/. Its kinetic temperature, as derived from CO( J = 2 ..-->.. 1)/CO( J = 1 ..-->.. 0) and /sup 13/CO( J = 2 ..-->.. 1)//sup 13/CO( J = 1 ..-->.. 0) ratios, is low, only 7-15 K. This temperature, when combined with the HCO/sup 1/( J = 3 ..-->.. 2)/HCO/sup +/( J = 1 ..-->.. 0) ratio, gives a density estimate of 10/sup 6/-10/sup 7/ cm/sup -3/. The HCO/sup +/ abundance in the disturbed gas seems to be normal or somewhat enhanced, in contradiction to theoretical expectations.« less

Rapid Thermal Annealing for Solution Synthesis of Transparent Conducting Aluminum Zinc Oxide Thin Films

NASA Astrophysics Data System (ADS)

Ullah, Sana; De Matteis, Fabio; Davoli, Ivan

2017-11-01

Transparent conducting oxide films with optimized dopant molar ratio have been prepared with limited pre- and postdeposition annealing duration of 10 min. Multiple aluminum zinc oxide (AZO) layers were spin-coated on ordinary glass substrates. The predeposition consolidation temperature and dopant molar ratio were optimized for electrical conductivity and optical transparency. Next, a group of films were deposited on Corning glass substrates from precursor solutions with the optimized dopant ratio, followed by postdeposition rapid thermal annealing (RTA) at different temperatures and in controlled environments. The lowest resistivity of 10.1 × 10-3 Ω cm was obtained for films receiving RTA at 600°C for 10 min each in vacuum then in N2-5%H2 environment, while resistivity of 20.3 × 10-3 Ω cm was obtained for films subjected to RTA directly in N2-5%H2. Optical measurements revealed average total transmittance of about 85% in the visible region. A direct allowed transition bandgap was determined based on the absorption edge with a value slightly above 3.0 eV, within the typical range for semiconductors. RTA resulted in desorption of oxygen with enhanced carrier concentration and crystallinity, which increased the carrier mobility with decreased bulk resistivity while maintaining the required optical transparency.

Thermal and electron transport studies on the valence fluctuating compound YbNiAl4

NASA Astrophysics Data System (ADS)

Falkowski, M.; Kowalczyk, A.

2018-05-01

We report the thermoelectric power S and thermal conductivity κ measurements on the valence fluctuating compound YbNiAl4, furthermore taking into account the impact of the applied magnetic field. We discuss our new results with revisiting the magnetic [χ(T)], transport [ρ(T)], and thermodynamic [Cp(T)] properties in order to better understand the phenomenon of thermal and electron transport in this compound. The field dependence of the magnetoresistivity data is also given. The temperature dependence of thermoelectric power S(T) was found to exhibit a similar behaviour as expected for Yb-based compounds with divalent or nearly divalent Yb ions. In addition, the values of total thermal conductivity as a function of temperature κ(T) of YbNiAl4 are fairly low compared to those of pure metals which may be linked to the fact that the conduction band is perturbed by strong hybridization. A deeper analysis of the specific heat revealed the low-T anomaly of the ratio Cp(T)/T3, most likely associated with the localized low-frequency oscillators in this alloy. In addition, the Kadowaki-Woods ratio and the Wilson ratio are discussed with respect to the electronic correlations in YbNiAl4.

Incubation temperature causes skewed sex ratios in a precocial bird.

PubMed

DuRant, Sarah E; Hopkins, William A; Carter, Amanda W; Kirkpatrick, Laila T; Navara, Kristin J; Hawley, Dana M

2016-07-01

Many animals with genetic sex determination are nonetheless capable of manipulating sex ratios via behavioral and physiological means, which can sometimes result in fitness benefits to the parent. Sex ratio manipulation in birds is not widely documented, and revealing the mechanisms for altered sex ratios in vertebrates remains a compelling area of research. Incubation temperature is a key component of the developmental environment for birds, but despite its well-documented effects on offspring phenotype it has rarely been considered as a factor in avian sex ratios. Using ecologically relevant manipulations of incubation temperature within the range 35.0-37.0°C, we found greater mortality of female embryos during incubation than males regardless of incubation temperature, and evidence that more female than male embryos die at the lowest incubation temperature (35.0°C). Our findings in conjunction with previous work in brush turkeys suggest incubation temperature is an important determinant of avian secondary sex ratios that requires additional study, and should be considered when estimating the impact of climate change on avian populations. © 2016. Published by The Company of Biologists Ltd.

An Assessment of the Use of Antimisting Fuel in Turbofan Engines.

DTIC Science & Technology

1981-06-01

Angle PLA Shutoff Lever Angle SOLA Control Speed Nc Compressor Discharge Pressure Ps4 or Pb Compr’ssor Inlet Temperature Tt2 Metered Fuel Flow Wf Control...this comparison the Royal Aircraft Establishment deqrader had a lower filter ratio reduction, consumed more power, and had a higher tempera- ture rise...negligible. This would imply that little of the total enerqy consume 1 by the pump goes towa~rds d(,qrading the antimisting kerosene. Further dita analysis

New Examination of the Traditional Raman Lidar Technique II: Evaluating the Ratios for Water Vapor and Aerosols

NASA Technical Reports Server (NTRS)

Whiteman, David N.

2003-01-01

In a companion paper, the temperature dependence of Raman scattering and its influence on the Raman and Rayleigh-Mie lidar equations was examined. New forms of the lidar equation were developed to account for this temperature sensitivity. Here those results are used to derive the temperature dependent forms of the equations for the water vapor mixing ratio, aerosol scattering ratio, aerosol backscatter coefficient, and extinction to backscatter ratio (Sa). The error equations are developed, the influence of differential transmission is studied and different laser sources are considered in the analysis. The results indicate that the temperature functions become significant when using narrowband detection. Errors of 5% and more can be introduced in the water vapor mixing ratio calculation at high altitudes and errors larger than 10% are possible for calculations of aerosol scattering ratio and thus aerosol backscatter coefficient and extinction to backscatter ratio.

[Sex ratio and environmental influence on population growth rate of Callinectes bellicosus (Decapoda: Portunidae) in the Gulf of California].

PubMed

Rodríguez-Félix, Demetrio; Cisneros-Mata, Miguel Angel; Aragón-Noriega, Eugenio Alberto; Arreola-Lizárraga, José Alfredo

2016-09-01

The brown swimming crab (Callinectes bellicosus) is an economically important species in the Gulf of California, and its fishing activity, held in Sonora from 1986, has been affected by a 20-year declining trend in its biomass. With the aim to understand the possible reasons of this species population changes along time, we estimated population growth rate (r) and sex ratio of C. bellicosus, and combined them with three parameters describing its habitat: sea temperature, wetland extension and habitat size in four areas along the coast of Sonora. For this, monthly mean sex ratio was estimated from crabs samples obtained from commercial catches during 1998-2002 and 2012; mean sea surface temperature for the spawning period (May-August) were derived from remote sensors for the same years; while wetland coverages were obtained from published reports, and habitat size was estimated as the fishing surface. For each area, r was estimated using a method developed for limited data situations using commercial landings (t) from 1986-2013. With data from the four areas, simple and multiple linear regression models were developed to ascertain theoretical sensitivities of r to variations in sex ratio and environmental parameters. A total of 24 556 crabs were sampled; males dominated (68.8 %) over females during the study period and in all areas; a cluster analysis identified two groups according to sex ratio: a Northern group with zones 1 and 2, and a Southern group with zones 3 and 4. r values were different in all zones (P<0.001) as was sex ratio (P=0.037); no differences in temperature were identified within the study years (P>0.995). Both the estimated data and sensitivity analyses suggest the existence of a direct and positive dependence of r on the proportion of female crabs and wetland size. We hypothesize that excess fishing of females caused the declining biomass trend of the brown swimming crab in Sonora, and concluded on the convenience of implementing harvest refugia inside coastal wetlands to protect females during the spawning season.

Spatial and temporal agreement in climate model simulations of the Interdecadal Pacific Oscillation

DOE PAGES

Henley, Benjamin J.; Meehl, Gerald; Power, Scott B.; ...

2017-01-31

Accelerated warming and hiatus periods in the long-term rise of Global Mean Surface Temperature (GMST) have, in recent decades, been associated with the Interdecadal Pacific Oscillation (IPO). Critically, decadal climate prediction relies on the skill of state-of-the-art climate models to reliably represent these low-frequency climate variations. We undertake a systematic evaluation of the simulation of the IPO in the suite of Coupled Model Intercomparison Project 5 (CMIP5) models. We track the IPO in pre-industrial (control) and all-forcings (historical) experiments using the IPO tripole index (TPI). The TPI is explicitly aligned with the observed spatial pattern of the IPO, and circumventsmore » assumptions about the nature of global warming. We find that many models underestimate the ratio of decadal-to-total variance in sea surface temperatures (SSTs). However, the basin-wide spatial pattern of positive and negative phases of the IPO are simulated reasonably well, with spatial pattern correlation coefficients between observations and models spanning the range 0.4–0.8. Deficiencies are mainly in the extratropical Pacific. Models that better capture the spatial pattern of the IPO also tend to more realistically simulate the ratio of decadal to total variance. Of the 13% of model centuries that have a fractional bias in the decadal-to-total TPI variance of 0.2 or less, 84% also have a spatial pattern correlation coefficient with the observed pattern exceeding 0.5. This result is highly consistent across both IPO positive and negative phases. This is evidence that the IPO is related to one or more inherent dynamical mechanisms of the climate system.« less

Spatial and temporal agreement in climate model simulations of the Interdecadal Pacific Oscillation

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

Henley, Benjamin J.; Meehl, Gerald; Power, Scott B.

Accelerated warming and hiatus periods in the long-term rise of Global Mean Surface Temperature (GMST) have, in recent decades, been associated with the Interdecadal Pacific Oscillation (IPO). Critically, decadal climate prediction relies on the skill of state-of-the-art climate models to reliably represent these low-frequency climate variations. We undertake a systematic evaluation of the simulation of the IPO in the suite of Coupled Model Intercomparison Project 5 (CMIP5) models. We track the IPO in pre-industrial (control) and all-forcings (historical) experiments using the IPO tripole index (TPI). The TPI is explicitly aligned with the observed spatial pattern of the IPO, and circumventsmore » assumptions about the nature of global warming. We find that many models underestimate the ratio of decadal-to-total variance in sea surface temperatures (SSTs). However, the basin-wide spatial pattern of positive and negative phases of the IPO are simulated reasonably well, with spatial pattern correlation coefficients between observations and models spanning the range 0.4–0.8. Deficiencies are mainly in the extratropical Pacific. Models that better capture the spatial pattern of the IPO also tend to more realistically simulate the ratio of decadal to total variance. Of the 13% of model centuries that have a fractional bias in the decadal-to-total TPI variance of 0.2 or less, 84% also have a spatial pattern correlation coefficient with the observed pattern exceeding 0.5. This result is highly consistent across both IPO positive and negative phases. This is evidence that the IPO is related to one or more inherent dynamical mechanisms of the climate system.« less

Biogas Production by Co-Digestion of Goat Manure with Three Crop Residues

PubMed Central

Zhang, Tong; Liu, Linlin; Song, Zilin; Ren, Guangxin; Feng, Yongzhong; Han, Xinhui; Yang, Gaihe

2013-01-01

Goat manure (GM) is an excellent raw material for anaerobic digestion because of its high total nitrogen content and fermentation stability. Several comparative assays were conducted on the anaerobic co-digestion of GM with three crop residues (CRs), namely, wheat straw (WS), corn stalks (CS) and rice straw (RS), under different mixing ratios. All digesters were implemented simultaneously under mesophilic temperature at 35±1 °C with a total solid concentration of 8%. Result showed that the combination of GM with CS or RS significantly improved biogas production at all carbon-to-nitrogen (C/N) ratios. GM/CS (30:70), GM/CS (70:30), GM/RS (30:70) and GM/RS (50:50) produced the highest biogas yields from different co-substrates (14840, 16023, 15608 and 15698 mL, respectively) after 55 d of fermentation. Biogas yields of GM/WS 30:70 (C/N 35.61), GM/CS 70:30 (C/N 21.19) and GM/RS 50:50 (C/N 26.23) were 1.62, 2.11 and 1.83 times higher than that of CRs, respectively. These values were determined to be the optimal C/N ratios for co-digestion. However, compared with treatments of GM/CS and GM/RS treatments, biogas generated from GM/WS was only slightly higher than the single digestion of GM or WS. This result was caused by the high total carbon content (35.83%) and lignin content (24.34%) in WS, which inhibited biodegradation. PMID:23825574

Stoichiometric evaluation of partial nitritation, anammox and denitrification processes in a sequencing batch reactor and interpretation of online monitoring parameters.

PubMed

Langone, Michela; Ferrentino, Roberta; Cadonna, Maria; Andreottola, Gianni

2016-12-01

A laboratory-scale sequencing batch reactor (SBR) performing partial nitritation - anammox and denitrification was used to treat anaerobic digester effluents. The SBR cycle consisted of a short mixing filling phase followed by oxic and anoxic reaction phases. Working at 25 °C, an ammonium conversion efficiency of 96.5%, a total nitrogen removal efficiency of 88.6%, and an organic carbon removal efficiency of 63.5% were obtained at a nitrogen loading rate of 0.15 kg N m -3 d -1 , and a biodegradable organic carbon to nitrogen ratio of 0.37. The potential contribution of each biological process was evaluated by using a stoichiometric model. The nitritation contribution decreased as the temperature decreased, while the contribution from anammox depended on the wastewater type and soluble carbon to nitrogen ratio. Denitrification improved the total nitrogen removal efficiency, and it was influenced by the biodegradable organic carbon to nitrogen ratio. The characteristic patterns of conductivity, oxidation-reduction potential (ORP) and pH in the SBR cycle were well related to biological processes. Conductivity profiles were found to be directly related to the decreasing profiles of ammonium. Positive ORP values at the end of the anoxic phases were detected for total nitrogen removal efficiency of lower than 85%, and the occurrence of bending points on the ORP curves during the anoxic phases was associated with nitrite depletion by the anammox process. Copyright © 2016 Elsevier Ltd. All rights reserved.

Efficient water removal in lipase-catalyzed esterifications using a low-boiling-point azeotrope.

PubMed

Yan, Youchun; Bornscheuer, Uwe T; Schmid, Rolf D

2002-04-05

High conversions in lipase-catalyzed syntheses of esters from free acyl donors and an alcohol requires efficient removal of water preferentially at temperatures compatible to enzyme activity. Using a lipase B from Candida antarctica (CAL-B)-mediated synthesis of sugar fatty-acid esters, we show that a mixture of ethyl methylketone (EMK) and hexane (best ratio: 4:1, vo/vo) allows efficient removal of water generated during esterification. Azeotropic distillation of the solvent mixture (composition: 26% EMK, 55% hexane, 19% water) takes place at 59 degrees C, which closely matches the optimum temperature reported for CAL-B. Water is then removed from the azeotrope by membrane vapor permeation. In case of glucose stearate, 93% yield was achieved after 48 h using an equimolar ratio of glucose and stearic acid. CAL-B could be reused for seven reaction cycles, with 86% residual activity after 14 d total reaction time at 59 degrees C. A decrease in fatty-acid chain length as well as increasing temperatures (75 degrees C) resulted in lower conversions. In addition, immobilization of CAL-B on a magnetic polypropylene carrier (EP 100) facilitated separation of the biocatalyst. Copyright 2002 Wiley Periodicals, Inc. Biotechnol Bioeng 78: 31--34, 2002; DOI 10.1002/bit.10084

Design of a superconducting volume coil for magnetic resonance microscopy of the mouse brain

NASA Astrophysics Data System (ADS)

Nouls, John C.; Izenson, Michael G.; Greeley, Harold P.; Johnson, G. Allan

2008-04-01

We present the design process of a superconducting volume coil for magnetic resonance microscopy of the mouse brain at 9.4 T. The yttrium barium copper oxide coil has been designed through an iterative process of three-dimensional finite-element simulations and validation against room temperature copper coils. Compared to previous designs, the Helmholtz pair provides substantially higher B1 homogeneity over an extended volume of interest sufficiently large to image biologically relevant specimens. A custom-built cryogenic cooling system maintains the superconducting probe at 60 ± 0.1 K. Specimen loading and probe retuning can be carried out interactively with the coil at operating temperature, enabling much higher through-put. The operation of the probe is a routine, consistent procedure. Signal-to-noise ratio in a mouse brain increased by a factor ranging from 1.1 to 2.9 as compared to a room-temperature solenoid coil optimized for mouse brain microscopy. We demonstrate images encoded at 10 × 10 × 20 μm for an entire mouse brain specimen with signal-to-noise ratio of 18 and a total acquisition time of 16.5 h, revealing neuroanatomy unseen at lower resolution. Phantom measurements show an effective spatial resolution better than 20 μm.

Comparative assessment of various lipid extraction protocols and optimization of transesterification process for microalgal biodiesel production.

PubMed

Mandal, Shovon; Patnaik, Reeza; Singh, Amit Kumar; Mallick, Nirupama

2013-01-01

Biodiesel, using microalgae as feedstocks, is being explored as the most potent form of alternative diesel fuel for sustainable economic development. A comparative assessment of various protocols for microalgal lipid extraction was carried out using five green algae, six blue-green algae and two diatom species treated with different single and binary solvents both at room temperature and using a soxhlet. Lipid recovery was maximum with chloroform-methanol in the soxhlet extractor. Pretreatments ofbiomass, such as sonication, homogenization, bead-beating, lyophilization, autoclaving, microwave treatment and osmotic shock did not register any significant rise in lipid recovery. As lipid recovery using chloroform-methanol at room temperature demonstrated a marginally lower value than that obtained under the soxhlet extractor, on economical point of view, the former is recommended for microalgal total lipid extraction. Transesterification process enhances the quality of biodiesel. Experiments were designed to determine the effects of catalyst type and quantity, methanol to oil ratio, reaction temperature and time on the transesterification process using response surface methodology. Fatty acid methyl ester yield reached up to 91% with methanol:HCl:oil molar ratio of 82:4:1 at 65 degrees C for 6.4h reaction time. The biodiesel yield relative to the weight of the oil was found to be 69%.

Investigation of two-phase thermosyphon performance filled with modern HFC refrigerants

NASA Astrophysics Data System (ADS)

Gorecki, Grzegorz

2018-02-01

Two-phase closed thermosyphons (TPCTs) are widely utilized as heat exchanger elements in waste heat recovery systems and as passive heating/cooling devices. They are popular because of their high thermal conductivity, simple construction and reliability. Previous researches indicate that refrigerants are performing better than typical TPCT working fluids like deionized water or alcohols in the low temperature range. In the present study three HFC (Hydrofluorocarbons) refrigerants were tested: R134a, R404A and R407C. The total length of the investigated TPCT is 550 mm with equal length (245 mm) condenser and evaporator sections. Its outer diameter is 22 mm with 1 mm wall thickness. The evaporator section was heated by hot water with varying inlet temperature by 5 K step in the range of 288 K - 323 K. The condenser was cooled by cold water with inlet temperature kept at a constant value of 283 K. It was found that using R134a and R404A as working fluids heat transfer rates are the highest. For both refrigerants 10% is optimal filling ratio. They can be utilized interchangeably because the differences between their throughputs are within uncertainty bands. R407C performance was 50% lower. Other disadvantages of using this refrigerant are relatively high working pressures and higher optimal filling ratio (30%).

Design of a superconducting volume coil for magnetic resonance microscopy of the mouse brain.

PubMed

Nouls, John C; Izenson, Michael G; Greeley, Harold P; Johnson, G Allan

2008-04-01

We present the design process of a superconducting volume coil for magnetic resonance microscopy of the mouse brain at 9.4T. The yttrium barium copper oxide coil has been designed through an iterative process of three-dimensional finite-element simulations and validation against room temperature copper coils. Compared to previous designs, the Helmholtz pair provides substantially higher B(1) homogeneity over an extended volume of interest sufficiently large to image biologically relevant specimens. A custom-built cryogenic cooling system maintains the superconducting probe at 60+/-0.1K. Specimen loading and probe retuning can be carried out interactively with the coil at operating temperature, enabling much higher through-put. The operation of the probe is a routine, consistent procedure. Signal-to-noise ratio in a mouse brain increased by a factor ranging from 1.1 to 2.9 as compared to a room-temperature solenoid coil optimized for mouse brain microscopy. We demonstrate images encoded at 10x10x20mum for an entire mouse brain specimen with signal-to-noise ratio of 18 and a total acquisition time of 16.5h, revealing neuroanatomy unseen at lower resolution. Phantom measurements show an effective spatial resolution better than 20mum.

Investigation of two-phase thermosyphon performance filled with modern HFC refrigerants

NASA Astrophysics Data System (ADS)

Gorecki, Grzegorz

2018-07-01

Two-phase closed thermosyphons (TPCTs) are widely utilized as heat exchanger elements in waste heat recovery systems and as passive heating/cooling devices. They are popular because of their high thermal conductivity, simple construction and reliability. Previous researches indicate that refrigerants are performing better than typical TPCT working fluids like deionized water or alcohols in the low temperature range. In the present study three HFC (Hydrofluorocarbons) refrigerants were tested: R134a, R404A and R407C. The total length of the investigated TPCT is 550 mm with equal length (245 mm) condenser and evaporator sections. Its outer diameter is 22 mm with 1 mm wall thickness. The evaporator section was heated by hot water with varying inlet temperature by 5 K step in the range of 288 K - 323 K. The condenser was cooled by cold water with inlet temperature kept at a constant value of 283 K. It was found that using R134a and R404A as working fluids heat transfer rates are the highest. For both refrigerants 10% is optimal filling ratio. They can be utilized interchangeably because the differences between their throughputs are within uncertainty bands. R407C performance was 50% lower. Other disadvantages of using this refrigerant are relatively high working pressures and higher optimal filling ratio (30%).

Microwave-assisted extraction and a new determination method for total steroid saponins from Dioscorea zingiberensis C.H. Wright.

PubMed

Ren, Yao; Chen, Yu; Hu, Bohan; Wu, Hui; Lai, Furao; Li, Xiaofeng

2015-12-01

An efficient microwave-assisted extraction (MAE) technique was applied to isolate total steroid saponins from Dioscorea zingiberensis C.H. Wright (DZW). The optimal extracting conditions were established as 75% ethanol as solvent, ratio of solid/liquid 1:20 (g/ml), temperature 75 °C, irradiation power 600 W and three extraction cycles of 6 min each. Scanning electron microscopy (SEM) images of DZW processed by four different extractions provided visual evidence of the disruption effect on DZW. Diosgenin was quantified by HPLC and examined further by LC-ESI/MS after acid hydrolysis. Total steroid saponins were calculated using diosgenin from total steroid saponins. The MAE procedure was optimized, validated and compared with other conventional extraction processes. This report provides a convenient technology for the extraction and quantification of total saponins of DZW combining MAE with HPLC and LC-ESI/MS for the first time. Copyright © 2015 Elsevier Inc. All rights reserved.

Space Power Free-Piston Stirling Engine Scaling Study

NASA Technical Reports Server (NTRS)

Jones, D.

1989-01-01

The design feasibility study is documented of a single cylinder, free piston Stirling engine/linear alternator (FPSE/LA) power module generating 150 kW-electric (kW sub e), and the determination of the module's maximum feasible power level. The power module configuration was specified to be a single cylinder (single piston, single displacer) FPSE/LA, with tuning capacitors if required. The design requirements were as follows: (1) Maximum electrical power output; (2) Power module thermal efficiency equal to or greater than 20 percent at a specific mass of 5 to 8 kg/kW(sub e); (3) Heater wall temperature/cooler wall temperature = 1050 K/525 K; (4) Sodium heat-pipe heat transport system, pumped loop NaK (sodium-potassium eutectic mixture) rejection system; (5) Maximum power module vibration amplitude = 0.0038 cm; and (6) Design life = 7 years (60,000 hr). The results show that a single cylinder FPSE/LA is capable of meeting program goals and has attractive scaling attributes over the power range from 25 to 150 kW(sub e). Scaling beyond the 150 kW(sub e) power level, the power module efficiency falls and the power module specific mass reaches 10 kg/kW(sub e) at a power output of 500 kW(sub e). A discussion of scaling rules for the engine, alternator, and heat transport systems is presented, along with a detailed description of the conceptual design of a 150 kW(sub e) power module that meets the requirements. Included is a discussion of the design of a dynamic balance system. A parametric study of power module performance conducted over the power output range of 25 to 150 kW(sub e) for temperature ratios of 1.7, 2.0, 2.5, and 3.0 is presented and discussed. The results show that as the temperature ratio decreases, the efficiency falls and specific mass increases. At a temperature ratio of 1.7, the 150 kW(sub e) power module cannot satisfy both efficiency and specific mass goals. As the power level increases from 25 to 150 kW(sub e) at a fixed temperature ratio, power module efficiency is seen to increase slightly, but at the expense of increased specific mass. An empirical equation relating power module thermal efficiency as a function of power module specific mass, power output, and temperature ratio is developed. Alternative configurations to the single cylinder, direct coupled linear alternator approach are also evaluated, but are shown to have technical drawbacks that lessen their attractiveness. The dynamic balance assembly mass (moving mass and structure) represents 20 to 30 percent of the total single cylinder power module mass. Joining two modules in a balanced opposed configuration eliminates the need for the balancer, and a hot end junction can be made without significant addition of structural mass. Recommendations are made for evaluation of advanced heat pipe concepts, tests of radial flow heat exchangers, and evaluation of high temperature alternator materials.

Suppression of Boride Formation in Transient Liquid Phase Bonding of Pairings of Parent Superalloy Materials with Different Compositions and Grain Structures and Resulting Mechanical Properties

NASA Astrophysics Data System (ADS)

Steuer, Susanne; Singer, Robert F.

2014-07-01

Two Ni-based superalloys, columnar grained Alloy 247 and single-crystal PWA1483, are joined by transient liquid phase bonding using an amorphous brazing foil containing boron as a melting point depressant. At lower brazing temperatures, two different morphologies of borides develop in both base materials: plate-like and globular ones. Their ratio to each other is temperature dependent. With very high brazing temperatures, the deleterious boride formation in Alloy 247 can be totally avoided, probably because the three-phase-field moves to higher alloying element contents. For the superalloy PWA1483, the formation of borides cannot be completely avoided at high brazing temperatures as incipient melting occurs. During subsequent solidification of these areas, Chinese-script-like borides precipitate. The mechanical properties (tensile tests at room and elevated temperatures and short-term creep rupture tests at elevated temperatures) for brazed samples without boride precipitation are very promising. Tensile strengths and creep times to 1 pct strain are comparable, respectively, higher than the ones of the weaker parent material for all tested temperatures and creep conditions (from 90 to 100 pct rsp. 175 to 250 pct).

Characteristics of maize biochar with different pyrolysis temperatures and its effects on organic carbon, nitrogen and enzymatic activities after addition to fluvo-aquic soil.

PubMed

Wang, Xiubin; Zhou, Wei; Liang, Guoqing; Song, Dali; Zhang, Xiaoya

2015-12-15

In this study, the characteristics of maize biochar produced at different pyrolysis temperatures (300, 450 and 600°C) and its effects on organic carbon, nitrogen and enzymatic activities after addition to fluvo-aquic soil were investigated. As pyrolysis temperature increased, ash content, pH, electrical conductivity, surface area, pore volume and aromatic carbon content of biochar increased while yield, ratios of oxygen:carbon and hydrogen: carbon and alkyl carbon content decreased. During incubation, SOC, total N, and ammonium-N contents increased in all biochar-amended treatments compared with the urea treatment; however, soil nitrate-N content first increased and then decreased with increasing pyrolysis temperature of the applied biochar. Extracellular enzyme activities associated with carbon transformation first increased and then decreased with biochars pyrolyzed at 450 and 600°C. Protease activity markedly increased with increased pyrolysis temperatures, whereas pyrolysis temperature had limited effect on soil urease activity. The results indicated that the responses of extracellular enzymes to biochar were dependent on the pyrolysis temperature, the enzyme itself and incubation time as well. Copyright © 2015. Published by Elsevier B.V.

Temperature and pressure influence on explosion pressures of closed vessel propane-air deflagrations.

PubMed

Razus, Domnina; Brinzea, Venera; Mitu, Maria; Oancea, Dumitru

2010-02-15

An experimental study on pressure evolution during closed vessel explosions of propane-air mixtures was performed, for systems with various initial concentrations and pressures ([C(3)H(8)]=2.50-6.20 vol.%, p(0)=0.3-1.2 bar). The explosion pressures and explosion times were measured in a spherical vessel (Phi=10 cm), at various initial temperatures (T(0)=298-423 K) and in a cylindrical vessel (Phi=10 cm; h=15 cm), at ambient initial temperature. The experimental values of explosion pressures are examined against literature values and compared to adiabatic explosion pressures, computed by assuming chemical equilibrium within the flame front. The influence of initial pressure, initial temperature and fuel concentration on explosion pressures and explosion times are discussed. At constant temperature and fuel/oxygen ratio, the explosion pressures are linear functions of total initial pressure, as reported for other fuel-air mixtures. At constant initial pressure and composition, both the measured and calculated (adiabatic) explosion pressures are linear functions of reciprocal value of initial temperature. Such correlations are extremely useful for predicting the explosion pressures of flammable mixtures at elevated temperatures and/or pressures, when direct measurements are not available.

In-flight boundary-layer measurements on a hollow cylinder at a Mach number of 3.0

NASA Technical Reports Server (NTRS)

Quinn, R. D.; Gong, L.

1980-01-01

Skin temperatures, shear forces, surface static pressures, boundary layer pitot pressures, and boundary layer total temperatures were measured on the external surface of a hollow cylinder that was 3.04 meters long and 0.437 meter in diameter and was mounted beneath the fuselage of the YF-12A airplane. The data were obtained at a nominal free stream Mach number of 3.0 (a local Mach number of 2.9) and at wall to recovery temperature ratios of 0.66 to 0.91. The local Reynolds number had a nominal value of 4,300,000 per meter. Heat transfer coefficients and skin friction coefficients were derived from skin temperature time histories and shear force measurements, respectively. In addition, boundary layer velocity profiles were derived from pitot pressure measurements, and a Reynolds analogy factor was obtained from the heat transfer and skin friction measurements. The measured data are compared with several boundary layer prediction methods.

Viscosity, density, and surface tension of binary mixtures of water and N-methyldiethanolamine and water and diethanolamine and tertiary mixtures of these amines with water over the temperature range 20--100[degree]C

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

Rinker, E.B.; Oelschlager, D.W.; Colussi, A.T.

1994-04-01

Aqueous solutions of N-methyldiethanolamine (MDEA) and diethanolamine (DEA) are widely used in the industrial treatment of acid gas streams containing H[sub 2]S and CO[sub 2]. The density and viscosity of aqueous solutions of N-methyldiethanolamine were measured over the temperature range 60--100 C. The density and viscosity of aqueous solutions of diethanolamine and diethanolamine + N-methyldiethanolamine were measured over the temperature range 20--100 C. The surface tension of aqueous solutions of the above mixtures was measured over the temperature range 20--80 C. The concentration ranges were 10--50 mass % N-methyldiethanolamine, 10--30 mass % diethanolamine, and 50 mass % total amine concentrationmore » with mass ratios of 0.0441--0.5883 (diethanolamine to N-methyldiethanolamine). The measured quantities were found to be in agreement with the literature where data were available.« less

Method of generating hydrogen-storing hydride complexes

DOEpatents

None, None

2013-05-14

A ternary hydrogen storage system having a constant stoichiometric molar ratio of LiNH.sub.2:MgH.sub.2:LiBH.sub.4 of 2:1:1. It was found that the incorporation of MgH.sub.2 particles of approximately 10 nm to 20 nm exhibit a lower initial hydrogen release temperature of 150.degree. C. Furthermore, it is observed that the particle size of LiBNH quaternary hydride has a significant effect on the hydrogen sorption concentration with an optimum size of 28 nm. The as-synthesized hydrides exhibit two main hydrogen release temperatures, one around 160.degree. C. and the other around 300.degree. C., with the main hydrogen release temperature reduced from 310.degree. C. to 270.degree. C., while hydrogen is first reversibly released at temperatures as low as 150.degree. C. with a total hydrogen capacity of 6 wt. % to 8 wt. %. Detailed thermal, capacity, structural and microstructural properties have been demonstrated and correlated with the activation energies of these materials.

Hydrogen-storing hydride complexes

DOEpatents

Srinivasan, Sesha S [Tampa, FL; Niemann, Michael U [Venice, FL; Goswami, D Yogi [Tampa, FL; Stefanakos, Elias K [Tampa, FL

2012-04-10

A ternary hydrogen storage system having a constant stoichiometric molar ratio of LiNH.sub.2:MgH.sub.2:LiBH.sub.4 of 2:1:1. It was found that the incorporation of MgH.sub.2 particles of approximately 10 nm to 20 nm exhibit a lower initial hydrogen release temperature of 150.degree. C. Furthermore, it is observed that the particle size of LiBNH quaternary hydride has a significant effect on the hydrogen sorption concentration with an optimum size of 28 nm. The as-synthesized hydrides exhibit two main hydrogen release temperatures, one around 160.degree. C. and the other around 300.degree. C., with the main hydrogen release temperature reduced from 310.degree. C. to 270.degree. C., while hydrogen is first reversibly released at temperatures as low as 150.degree. C. with a total hydrogen capacity of 6 wt. % to 8 wt. %. Detailed thermal, capacity, structural and microstructural properties have been demonstrated and correlated with the activation energies of these materials.

Effects of rising temperature on the viability of an important sea turtle rookery

NASA Astrophysics Data System (ADS)

Laloë, Jacques-Olivier; Cozens, Jacquie; Renom, Berta; Taxonera, Albert; Hays, Graeme C.

2014-06-01

A warming world poses challenges for species with temperature-dependent sex determination, including sea turtles, for which warmer incubation temperatures produce female hatchlings. We combined in situ sand temperature measurements with air temperature records since 1850 and predicted warming scenarios from the Intergovernmental Panel on Climate Change to derive 250-year time series of incubation temperatures, hatchling sex ratios, and operational sex ratios for one of the largest sea turtles rookeries globally (Cape Verde Islands, Atlantic). We estimate that light-coloured beaches currently produce 70.10% females whereas dark-coloured beaches produce 93.46% females. Despite increasingly female skewed sex ratios, entire feminization of this population is not imminent. Rising temperatures increase the number of breeding females and hence the natural rate of population growth. Predicting climate warming impacts across hatchlings, male-female breeding ratios and nesting numbers provides a holistic approach to assessing the conservation concerns for sea turtles in a warming world.

Quality by Design approach for studying the impact of formulation and process variables on product quality of oral disintegrating films.

PubMed

Mazumder, Sonal; Pavurala, Naresh; Manda, Prashanth; Xu, Xiaoming; Cruz, Celia N; Krishnaiah, Yellela S R

2017-07-15

The present investigation was carried out to understand the impact of formulation and process variables on the quality of oral disintegrating films (ODF) using Quality by Design (QbD) approach. Lamotrigine (LMT) was used as a model drug. Formulation variable was plasticizer to film former ratio and process variables were drying temperature, air flow rate in the drying chamber, drying time and wet coat thickness of the film. A Definitive Screening Design of Experiments (DoE) was used to identify and classify the critical formulation and process variables impacting critical quality attributes (CQA). A total of 14 laboratory-scale DoE formulations were prepared and evaluated for mechanical properties (%elongation at break, yield stress, Young's modulus, folding endurance) and other CQA (dry thickness, disintegration time, dissolution rate, moisture content, moisture uptake, drug assay and drug content uniformity). The main factors affecting mechanical properties were plasticizer to film former ratio and drying temperature. Dissolution rate was found to be sensitive to air flow rate during drying and plasticizer to film former ratio. Data were analyzed for elucidating interactions between different variables, rank ordering the critical materials attributes (CMA) and critical process parameters (CPP), and for providing a predictive model for the process. Results suggested that plasticizer to film former ratio and process controls on drying are critical to manufacture LMT ODF with the desired CQA. Published by Elsevier B.V.

An Empirical Jet-Surface Interaction Noise Model with Temperature and Nozzle Aspect Ratio Effects

NASA Technical Reports Server (NTRS)

Brown, Cliff

2015-01-01

An empirical model for jet-surface interaction (JSI) noise produced by a round jet near a flat plate is described and the resulting model evaluated. The model covers unheated and hot jet conditions (1 less than or equal to jet total temperature ratio less than or equal to 2.7) in the subsonic range (0.5 less than or equal to M(sub a) less than or equal to 0.9), surface lengths 0.6 less than or equal to (axial distance from jet exit to surface trailing edge (inches)/nozzle exit diameter) less than or equal to 10, and surface standoff distances (0 less than or equal to (radial distance from jet lipline to surface (inches)/axial distance from jet exit to surface trailing edge (inches)) less than or equal to 1) using only second-order polynomials to provide predictable behavior. The JSI noise model is combined with an existing jet mixing noise model to produce exhaust noise predictions. Fit quality metrics and comparisons to between the predicted and experimental data indicate that the model is suitable for many system level studies. A first-order correction to the JSI source model that accounts for the effect of nozzle aspect ratio is also explored. This correction is based on changes to the potential core length and frequency scaling associated with rectangular nozzles up to 8:1 aspect ratio. However, more work is needed to refine these findings into a formal model.

Ignition and Performance Tests of Rocket-Based Combined Cycle Propulsion System

NASA Technical Reports Server (NTRS)

Anderson, William E.

2005-01-01

The ground testing of a Rocket Based Combined Cycle engine implementing the Simultaneous Mixing and Combustion scheme was performed at the direct-connect facility of Purdue University's High Pressure Laboratory. The fuel-rich exhaust of a JP-8/H2O2 thruster was mixed with compressed, metered air in a constant area, axisymmetric duct. The thruster was similar in design and function to that which will be used in the flight test series of Dryden's Ducted-Rocket Experiment. The determination of duct ignition limits was made based on the variation of secondary air flow rates and primary thruster equivalence ratios. Thrust augmentation and improvements in specific impulse were studied along with the pressure and temperature profiles of the duct to study mixing lengths and thermal choking. The occurrence of ignition was favored by lower rocket equivalence ratios. However, among ignition cases, better thrust and specific impulse performance were seen with higher equivalence ratios owing to the increased fuel available for combustion. Thrust and specific impulse improvements by factors of 1.2 to 1.7 were seen. The static pressure and temperature profiles allowed regions of mixing and heat addition to be identified. The mixing lengths were found to be shorter at lower rocket equivalence ratios. Total pressure measurements allowed plume-based calculation of thrust, which agreed with load-cell measured values to within 6.5-8.0%. The corresponding Mach Number profile indicated the flow was not thermally choked for the highest duct static pressure case.

Calculating High Speed Centrifugal Compressor Performance from Averaged Measurements

NASA Astrophysics Data System (ADS)

Lou, Fangyuan; Fleming, Ryan; Key, Nicole L.

2012-12-01

To improve the understanding of high performance centrifugal compressors found in modern aircraft engines, the aerodynamics through these machines must be experimentally studied. To accurately capture the complex flow phenomena through these devices, research facilities that can accurately simulate these flows are necessary. One such facility has been recently developed, and it is used in this paper to explore the effects of averaging total pressure and total temperature measurements to calculate compressor performance. Different averaging techniques (including area averaging, mass averaging, and work averaging) have been applied to the data. Results show that there is a negligible difference in both the calculated total pressure ratio and efficiency for the different techniques employed. However, the uncertainty in the performance parameters calculated with the different averaging techniques is significantly different, with area averaging providing the least uncertainty.

Influence of Soil Organic Matter Stabilization Mechanisms on Temperature Sensitivity of Soil Respiration

NASA Astrophysics Data System (ADS)

Gillabel, J.; de Gryze, S.; Six, J.; Merckx, R.

2007-12-01

Knowledge on the sensitivity of soil organic matter (SOM) respiration to changes in temperature is crucial for predicting future impacts of climate change on soil C stocks. Temperature sensitivity of respiration is determined by the chemical structure of the compound to be decomposed and by the availability of the organic matter for decomposers. Biochemically recalcitrant SOM has a higher temperature sensitivity than biochemically labile SOM. However, it is hypothesized that the stabilization of SOM by interaction with the soil matrix could be an important attenuating control on temperature sensitivity. We investigated the effect of different SOM stabilization mechanisms on temperature sensitivity of SOM respiration. Two main mechanisms were considered: chemical interactions of SOM with clay and silt particles, and physical protection inside aggregates. Soil samples from an agricultural silt loam soil were fractionated by wet-sieving into macroaggregates, microaggregates and silt+clay fractions. SOM stabilization in the silt+clay fraction occurs mainly chemically, whereas in aggregates physical protection of SOM is more important. Samples of each fraction and of bulk soil were incubated at two temperatures (20°C and 30°C) for one month. After 2% of total soil carbon was respired, temperature sensitivity was determined for respiration of the next 0.5% of total soil carbon. This was done by calculating a Q10 value as the ratio of the times needed at each temperature to respire that fraction of the soil C. This method allows determination of temperature sensitivity independent of C quality. Calculated Q10 values decreased in the order bulk soil > macroaggregates > microaggregates > silt+clay, with the difference between macroaggregate Q10 and silt+clay Q10 being the only significant difference. These results indicate that protection of SOM attenuates temperature sensitivity, with chemical protection (silt+clay) having a larger effect than physical protection (aggregates).

Distributed Control Architecture for Gas Turbine Engine. Chapter 4

NASA Technical Reports Server (NTRS)

Culley, Dennis; Garg, Sanjay

2009-01-01

The transformation of engine control systems from centralized to distributed architecture is both necessary and enabling for future aeropropulsion applications. The continued growth of adaptive control applications and the trend to smaller, light weight cores is a counter influence on the weight and volume of control system hardware. A distributed engine control system using high temperature electronics and open systems communications will reverse the growing trend of control system weight ratio to total engine weight and also be a major factor in decreasing overall cost of ownership for aeropropulsion systems. The implementation of distributed engine control is not without significant challenges. There are the needs for high temperature electronics, development of simple, robust communications, and power supply for the on-board electronics.

Altitude test of several afterburner configurations on a turbofan engine with a hydrogen heater to simulate an elevated turbine discharge temperature

NASA Technical Reports Server (NTRS)

Johnsen, R. L.; Cullom, R. R.

1977-01-01

A performance test of several experimental afterburner configurations was conducted with a mixed-flow turbofan engine in an altitude facility. The simulated flight conditions were for Mach 1.4 at two altitudes, 12,190 and 14,630 meters. Turbine discharge temperatures of 889 and 1056 K were used. A production afterburner was tested for comparison. The research afterburners included partial forced mixers with V-gutter flameholders, a carburetted V-gutter flameholder, and a triple ring V-gutter flameholder with four swirl-can fuel mixers. Fuel injection variations were included. Performance data shown include augmented thrust ratio, thrust specific fuel consumption, combustion efficiency, and total pressure drop across the afterburner.

Emery-Kivelson solution of the two-channel Kondo problem

NASA Astrophysics Data System (ADS)

Sengupta, Anirvan M.; Georges, Antoine

1994-04-01

We consider the two-channel Kondo model in the Emery-Kivelson approach, and calculate the total susceptibility enhancement due to the impurity χimp=χ-χbulk. We find that χimp exactly vanishes at the solvable point, in a completely analogous way to the singular part of the specific heat Cimp. A perturbative calculation around the solvable point yields the generic behavior χimp~log(1/T), Cimp~T logT and the known universal value of the Wilson ratio RW=8/3. From this calculation, the Kondo temperature can be identified and is found to behave as the inverse square of the perturbation parameter. The small-field, zero-temperature behavior χimp~log(1/h) is also recovered.

Heat Transfer and Cooling in Gas Turbines (Le Transfert Thermique et le Refroidissement dans les Turbines a Gaz)

DTIC Science & Technology

1993-02-01

the almost monotonic coolant to freestream temperature ratio ( Toc /To0 =0.62). increase of h/ho at low values of Toe/To1 compared to The non...Tol 0.769 0.4 es•e. 10 diem. 0.4 TocTol 0.889 &"a&’ 50 diam. 0.4 A Toc /TOI 0.817 A,’,’ Trailing edge 0Emisson S4 0.0 0.2 0.𔃾 o.8 06 1.0 0.25 0.60 01.5...for (M--0.98, Re2=5.5xlW0, Toc /To-ff0.4). The total impingement realized through a row of circular holes temperature boundary condition is the hot gas

Experimental evaluation of two premixing-prevaporizing fuel injection concepts for a gas turbine catalytic combustor

NASA Technical Reports Server (NTRS)

Tacina, R.

1976-01-01

A premixing-prevaporizing fuel system for a gas turbine catalytic combustor has been developed and evaluated. Spatial fuel distribution and degree of vaporization were measured at inlet temperatures up to 800 K and fuel-air ratios of 0.01 and 0.025. The test pressure was 0.5 MPa; velocity was 20 m/sec. Both a multiple-jet cross-stream injector and a splash-groove injector with a 30 deg air swirler exhibited a uniform fuel distribution and a high degree of vaporization with little total pressure drop. Fuel oxidation reactions were observed at the 800 K inlet air temperature, indicating that a different design concept is necessary for application with an automotive gas turbine.

Effect of Temperature on Mechanical Properties of Nanoclay Reinforced Polymeric Nanocomposites. Part 1. Experimental Results

DTIC Science & Technology

2012-04-23

Temperature and nanoclay reinforcement affect the Poisson ?s ratio also, but this effect is less significant. In general, as the temperature increases...the Poisson ?s ratio also increases. However, an increase in nanoclay reinforcement generally reduces the Poisson ?s ratio . It is also noted that the...nanoclay reinforcement generally reduces the Poisson’s ratio . It is also noted that the type of resin used may have a significant effect on the

Optimization of Ultrasound-Assisted Extraction, HPLC and UHPLC-ESI-Q-TOF-MS/MS Analysis of Main Macamides and Macaenes from Maca (Cultivars of Lepidium meyenii Walp).

PubMed

Chen, Shu-Xiao; Li, Ke-Ke; Pubu, Duoji; Jiang, Si-Ping; Chen, Bin; Chen, Li-Rong; Yang, Zhen; Ma, Chao; Gong, Xiao-Jie

2017-12-10

Ultrasound-assisted extraction (UAE), using petroleum ether as the solvent, was systematically applied to extract main macamides and macaenes from Maca hypocotyls. Extraction yield was related with four variables, including ratio of solution to solid, extraction temperature, extraction time, and extraction power. On the basis of response surface methodology (RSM), the optimal conditions were determined to be the ratio of solution to solid as 10:1 (mL/g), the extraction temperature of 40 °C, the extraction time of 30 min, and the extraction power of 200 W. Based on the optimal extraction method of UAE, the total contents of ten main macamides and two main macaenes of Maca cultivated in twenty different areas of Tibet were analyzed by HPLC and UHPLC-ESI-Q-TOF-MS/MS. This study indicated that UAE was able to effectively extract macamides alkaloids from Maca hypocotyls. Quantitative analysis showed that geographical origins, not ecotypes, played a more important role on the accumulation of active macamides in Maca.

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

Shahrukh, Hassan; Oyedun, Adetoyese Olajire; Kumar, Amit

Here, a process model was developed to determine the net energy ratio (NER) for production of pellets from steam pretreated agricultural residue (AR) and energy crop (i.e. switchgrass in this case). The NER is a ratio of the net energy output to the total net energy input from non-renewable energy sources into a system. Scenarios were developed to measure the effects of temperature and level of steam pretreatment on the NER of steam pretreated AR- and switch grass-based pellets. The NER for the base case at 6 kg h -1 is 1.76 and 1.37 for steam-pretreated AR- and switchgrass-based pellets,more » respectively. The reason behind the difference is that more energy is required to dry switchgrass pellets than AR pellets. The sensitivity analysis for the model shows that the optimum temperature for steam pretreatment is 160 C with 50% pretreatment (half the feedstock is pretreated, while the rest is undergoes regular pelletization). The uncertainty results for NER for steam pretreated AR and switch grass pellets are 1.62 ± 0.10 and 1.42 ± 0.11, respectively.« less

Green ultrasound-assisted extraction of carotenoids from pomegranate wastes using vegetable oils.

PubMed

Goula, Athanasia M; Ververi, Maria; Adamopoulou, Anna; Kaderides, Kyriakos

2017-01-01

The objective of this work was to develop a new process for pomegranate peels application in food industries based on ultrasound-assisted extraction of carotenoids using different vegetable oils as solvents. In this way, an oil enriched with antioxidants is produced. Sunflower oil and soy oil were used as alternative solvents and the effects of various parameters on extraction yield were studied. Extraction temperature, solid/oil ratio, amplitude level, and extraction time were the factors investigated with respect to extraction yield. Comparative studies between ultrasound-assisted and conventional solvent extraction were carried out in terms of processing procedure and total carotenoids content. The efficient extraction period for achieving maximum yield of pomegranate peel carotenoids was about 30min. The optimum operating conditions were found to be: extraction temperature, 51.5°C; peels/solvent ratio, 0.10; amplitude level, 58.8%; solvent, sunflower oil. A second-order kinetic model was successfully developed for describing the mechanism of ultrasound extraction under different processing parameters. Copyright © 2016 Elsevier B.V. All rights reserved.

Comparative evaluation of maceration and ultrasonic-assisted extraction of phenolic compounds from fresh olives.

PubMed

Deng, Junlin; Xu, Zhou; Xiang, Chunrong; Liu, Jing; Zhou, Lijun; Li, Tian; Yang, Zeshen; Ding, Chunbang

2017-07-01

Ultrasonic-assisted extraction (UAE) and maceration extraction (ME) were optimized using response surface methodology (RSM) for total phenolic compounds (TPC) from fresh olives. The main phenolic compounds and antioxidant activity of TPC were also investigated. The optimized result for UAE was 22mL/g of liquid-solid ratio, 47°C of extraction temperature and 30min of extraction time, 7.01mg/g of yielding, and for ME was 24mL/g of liquid-solid ratio, 50°C of extraction temperature and 4.7h of extraction time, 5.18mg/g of yielding. The HPLC analysis revealed that the extracts by UAE and ME possessed 14 main phenolic compounds, and UAE exhibited more amounts of all phenols than ME. The most abundant phenolic compounds in olive extracts were hydroxytyrosol, oleuropein and rutin. Both extracts showed excellent antioxidant activity in a dose-dependent manner. Taken together, UAE could effectively increase the yield of phenolic compounds from olives. In addition these phenolic compounds could be used as a potential source of natural antioxidants. Copyright © 2017 Elsevier B.V. All rights reserved.

Increasing Operational Stability in Low NOX GT Combustor Using Fuel Rich Concentric Pilot Combustor

NASA Astrophysics Data System (ADS)

Levy, Yeshayahou; Erenburg, Vladimir; Sherbaum, Valery; Ovcharenko, Vitali; Rosentsvit, Leonid; Chudnovsky, Boris; Herszage, Amiel; Talanker, Alexander

2012-03-01

Lean combustion is a method in which combustion takes place under low equivalence ratio and relatively low combustion temperatures. As such, it has the potential to lower the effect of the relatively high activation energy nitrogen-oxygen reactions which are responsible for substantial NOX formation during combustion processes. However, lowering temperature reduces the reaction rate and deteriorates combustion stability. The objective of the present study is to reduce the lower equivalence ratio limit of the stable combustion operational boundary in lean Gas Turbine (GT) combustors while still maintaining combustion stability. A lean premixed gaseous combustor was equipped with a surrounding concentric pilot flame operating under rich conditions, thus generating a hot stream of combustion products with significant amount of reactive radicals. The main combustor's fuel-air composition was varied from stoichiometric to lean mixtures. The pilot's mixture composition was also varied by changing the air flow rate, within a limited rich mixtures range. The pilot fuel flow rate was always lower than five percent of the total fuel supply at the specific stage of the experiments.

The Statistical Properties of Solar Wind Temperature Parameters Near 1 au

NASA Astrophysics Data System (ADS)

Wilson, Lynn B., III; Stevens, Michael L.; Kasper, Justin C.; Klein, Kristopher G.; Maruca, Bennett A.; Bale, Stuart D.; Bowen, Trevor A.; Pulupa, Marc P.; Salem, Chadi S.

2018-06-01

We present a long-duration (∼10 yr) statistical analysis of the temperatures, plasma betas, and temperature ratios for the electron, proton, and alpha-particle populations observed by the Wind spacecraft near 1 au. The mean(median) scalar temperatures are T e,tot = 12.2(11.9) eV, T p,tot = 12.7(8.6) eV, and T α,tot = 23.9(10.8) eV. The mean(median) total plasma betas are β e,tot = 2.31(1.09), β p,tot = 1.79(1.05), and β α,tot = 0.17(0.05). The mean(median) temperature ratios are (T e /T p )tot = 1.64(1.27), (T e /T α )tot = 1.24(0.82), and (T α /T p )tot = 2.50(1.94). We also examined these parameters during time intervals that exclude interplanetary (IP) shocks, times within the magnetic obstacles (MOs) of interplanetary coronal mass ejections (ICMEs), and times that exclude MOs. The only times that show significant alterations to any of the parameters examined are those during MOs. In fact, the only parameter that does not show a significant change during MOs is the electron temperature. Although each parameter shows a broad range of values, the vast majority are near the median. We also compute particle–particle collision rates and compare to effective wave–particle collision rates. We find that, for reasonable assumptions of wave amplitude and occurrence rates, the effect of wave–particle interactions on the plasma is equal to or greater than the effect of Coulomb collisions. Thus, wave–particle interactions should not be neglected when modeling the solar wind.

Temperature-dependent sex determination in fish revisited: prevalence, a single sex ratio response pattern, and possible effects of climate change.

PubMed

Ospina-Alvarez, Natalia; Piferrer, Francesc

2008-07-30

In gonochoristic vertebrates, sex determination mechanisms can be classified as genotypic (GSD) or temperature-dependent (TSD). Some cases of TSD in fish have been questioned, but the prevalent view is that TSD is very common in this group of animals, with three different response patterns to temperature. We analyzed field and laboratory data for the 59 fish species where TSD has been explicitly or implicitly claimed so far. For each species, we compiled data on the presence or absence of sex chromosomes and determined if the sex ratio response was obtained within temperatures that the species experiences in the wild. If so, we studied whether this response was statistically significant. We found evidence that many cases of observed sex ratio shifts in response to temperature reveal thermal alterations of an otherwise predominately GSD mechanism rather than the presence of TSD. We also show that in those fish species that actually have TSD, sex ratio response to increasing temperatures invariably results in highly male-biased sex ratios, and that even small changes of just 1-2 degrees C can significantly alter the sex ratio from 1:1 (males:females) up to 3:1 in both freshwater and marine species. We demonstrate that TSD in fish is far less widespread than currently believed, suggesting that TSD is clearly the exception in fish sex determination. Further, species with TSD exhibit only one general sex ratio response pattern to temperature. However, the viability of some fish populations with TSD can be compromised through alterations in their sex ratios as a response to temperature fluctuations of the magnitude predicted by climate change.

Distinct Contributions of Ice Nucleation, Large-Scale Environment, and Shallow Cumulus Detrainment to Cloud Phase Partitioning With NCAR CAM5

DOE PAGES

Wang, Yong; Zhang, Damao; Liu, Xiaohong; ...

2018-01-06

Mixed-phase clouds containing both liquid droplets and ice particles occur frequently at high latitudes and in the midlatitude storm track regions. Simulations of the cloud phase partitioning between liquid and ice hydrometeors in state-of-the-art global climate models are still associated with large biases. For this study, the phase partitioning in terms of liquid mass phase ratio (MPR liq, defined as the ratio of liquid mass to total condensed water mass) simulated from the NCAR Community Atmosphere Model version 5 (CAM5) is evaluated against the observational data from A-Train satellite remote sensors. Modeled MPR liq is significantly lower than observations onmore » the global scale, especially in the Southern Hemisphere (e.g., Southern Ocean and the Antarctic). Sensitivity tests with CAM5 are conducted to investigate the distinct contributions of heterogeneous ice nucleation, shallow cumulus detrainment, and large-scale environment (e.g., winds, temperature, and water vapor) to the low MPR liq biases. Our results show that an aerosol-aware ice nucleation parameterization increases the MPR liq especially at temperatures colder than -20°C and significantly improves the model agreements with observations in the Polar regions in summer. The decrease of threshold temperature over which all detrained cloud water is liquid from 268 to 253 K enhances the MPR liq and improves the MPR liq mostly over the Southern Ocean. By constraining water vapor in CAM5 toward reanalysis, modeled low biases in many geographical regions are largely reduced through a significant decrease of cloud ice mass mixing ratio.« less

Distinct Contributions of Ice Nucleation, Large-Scale Environment, and Shallow Cumulus Detrainment to Cloud Phase Partitioning With NCAR CAM5

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

Wang, Yong; Zhang, Damao; Liu, Xiaohong

Mixed-phase clouds containing both liquid droplets and ice particles occur frequently at high latitudes and in the midlatitude storm track regions. Simulations of the cloud phase partitioning between liquid and ice hydrometeors in state-of-the-art global climate models are still associated with large biases. For this study, the phase partitioning in terms of liquid mass phase ratio (MPR liq, defined as the ratio of liquid mass to total condensed water mass) simulated from the NCAR Community Atmosphere Model version 5 (CAM5) is evaluated against the observational data from A-Train satellite remote sensors. Modeled MPR liq is significantly lower than observations onmore » the global scale, especially in the Southern Hemisphere (e.g., Southern Ocean and the Antarctic). Sensitivity tests with CAM5 are conducted to investigate the distinct contributions of heterogeneous ice nucleation, shallow cumulus detrainment, and large-scale environment (e.g., winds, temperature, and water vapor) to the low MPR liq biases. Our results show that an aerosol-aware ice nucleation parameterization increases the MPR liq especially at temperatures colder than -20°C and significantly improves the model agreements with observations in the Polar regions in summer. The decrease of threshold temperature over which all detrained cloud water is liquid from 268 to 253 K enhances the MPR liq and improves the MPR liq mostly over the Southern Ocean. By constraining water vapor in CAM5 toward reanalysis, modeled low biases in many geographical regions are largely reduced through a significant decrease of cloud ice mass mixing ratio.« less

Distinct Contributions of Ice Nucleation, Large-Scale Environment, and Shallow Cumulus Detrainment to Cloud Phase Partitioning With NCAR CAM5

NASA Astrophysics Data System (ADS)

Wang, Yong; Zhang, Damao; Liu, Xiaohong; Wang, Zhien

2018-01-01

Mixed-phase clouds containing both liquid droplets and ice particles occur frequently at high latitudes and in the midlatitude storm track regions. Simulations of the cloud phase partitioning between liquid and ice hydrometeors in state-of-the-art global climate models are still associated with large biases. In this study, the phase partitioning in terms of liquid mass phase ratio (MPRliq, defined as the ratio of liquid mass to total condensed water mass) simulated from the NCAR Community Atmosphere Model version 5 (CAM5) is evaluated against the observational data from A-Train satellite remote sensors. Modeled MPRliq is significantly lower than observations on the global scale, especially in the Southern Hemisphere (e.g., Southern Ocean and the Antarctic). Sensitivity tests with CAM5 are conducted to investigate the distinct contributions of heterogeneous ice nucleation, shallow cumulus detrainment, and large-scale environment (e.g., winds, temperature, and water vapor) to the low MPRliq biases. Our results show that an aerosol-aware ice nucleation parameterization increases the MPRliq especially at temperatures colder than -20°C and significantly improves the model agreements with observations in the Polar regions in summer. The decrease of threshold temperature over which all detrained cloud water is liquid from 268 to 253 K enhances the MPRliq and improves the MPRliq mostly over the Southern Ocean. By constraining water vapor in CAM5 toward reanalysis, modeled low biases in many geographical regions are largely reduced through a significant decrease of cloud ice mass mixing ratio.

Performance of a Model Rich Burn-quick Mix-lean Burn Combustor at Elevated Temperature and Pressure

NASA Technical Reports Server (NTRS)

Peterson, Christopher O.; Sowa, William A.; Samuelsen, G. S.

2002-01-01

As interest in pollutant emission from stationary and aero-engine gas turbines increases, combustor engineers must consider various configurations. One configuration of increasing interest is the staged, rich burn - quick mix - lean burn (RQL) combustor. This report summarizes an investigation conducted in a recently developed high pressure gas turbine combustor facility. The model RQL combustor was plenum fed and modular in design. The fuel used for this study is Jet-A which was injected from a simplex atomizer. Emission (CO2, CO, O2, UHC, NOx) measurements were obtained using a stationary exit plane water-cooled probe and a traversing water-cooled probe which sampled from the rich zone exit and the lean zone entrance. The RQL combustor was operated at inlet temperatures ranging from 367 to 700 K, pressures ranging from 200 to 1000 kPa, and combustor reference velocities ranging from 10 to 20 m/s. Variations were also made in the rich zone and lean zone equivalence ratios. Several significant trends were observed. NOx production increased with reaction temperature, lean zone equivalence ratio and residence time and decreased with increased rich zone equivalence ratio. NOx production in the model RQL combustor increased to the 0.4 power with increased pressure. This correlation, compared to those obtained for non-staged combustors (0.5 to 0.7), suggests a reduced dependence on NOx on pressure for staged combustors. Emissions profiles suggest that rich zone mixing is not uniform and that the rich zone contributes on the order of 16 percent to the total NOx produced.

Chemical fractionation in the solar nebula

NASA Technical Reports Server (NTRS)

Grossman, L.

1977-01-01

The sequence of condensation of minerals from a cooling gas of solar composition has been calculated from thermodynamic data over the pressure range 0.001-0.00001 atm, assuming that complete chemical equilibrium is maintained. The results suggest that the Ca-Al-rich inclusions Allende and other carbonaceous chondrites are aggregates of the highest temperature condensates. Complete condensation of these elements is followed, 100 deg later, by the onset of the crystallization of nickel-iron, forsterite and enstatite. Transport of Ca-Al-rich refractory condensates from one part of the nebula to another before the condensation of these lower-temperature phases may have been responsible for the refractory element fractionations between the different classes of chondrites and possibly for the inferred refractory element enrichment of the Moon. The temperature gap between the condensation temperatures of nickel-iron and forsterite increases with increasing total pressure. Because pressure and temperature probably increased with decreasing heliocentric distance in the solar nebula, Mercury may have accreted from a condensate assemblage having a higher metal/silicate ratio than Venus or Earth which may, in turn, have formed from less oxidized material than Mars.

The primary solar-type atmosphere surrounding the accreting Earth: H2O-induced high surface temperature.

NASA Astrophysics Data System (ADS)

Sasaki, S.

In the solar nebula, a growing planet attracts ambient gas to form a solar-type atmosphere. The structure of this H2-He atmosphere is calculated assuming the Earth was formed in the nebula. The blanketing effect of the atmosphere renders the planetary surface molten when the planetary mass exceeds 0.2 ME (ME being the present Earth's mass). Reduction of the surface melt by atmospheric H2 should add a large amount of H2O to the atmosphere: under the quartz-iron-fayalite oxygen buffer, partial pressure ratio P(H2O)/P(H2) becomes higher than 0.1. Enhancing opacity and gas mean molecular weight, the excess H2O raises the temperature and renders the atmosphere in convective equilibrium, while the dissociation of H2 suppresses the adiabatic temperature gradient. The surface temperature of the proto-Earth can be as high as 4700K when its mass is 1 ME. Such a high temperature may accelerate the evaporation of surface materials. A deep totally-molten magma ocean should exist in the accretion Earth.

[Preliminary observation on survival and reproduction of imported Oncomelania snails in water network regions: a simulated experiment].

PubMed

Tian, Jian-Guo; Zhong, Wen-Jiang; Li, Gui-Fu; Peng, Li-Xia; Xiang, Xiao-Ping

2011-04-01

To observe the survival and reproduction of exotic imported Oncomelania snails in water network regions. During a period between May 22, 2008 and August 7, 2009, a study pilot was established in a historical snail habitat in Qingpu District of Shanghai City. A total of 12 soil samples were collected from Qingpu, Jinshan and Songjiang districts and placed in the study area. Active marked adults snails without infections (with a female/male ratio of 1) were placed on soil surface, and the activity, survival and reproduction of snails on soil surface were observed. The temperature during the period of the study was recorded. During the experiment period, the highest temperature was 39 degrees C, the lowest was -3 degrees C, and the average was 20 degrees C. The activity of snails reduced significantly on the soil surface at high temperature in summer and low temperature in winter. There were 91 old snails (5.2%) that moved on soil surface in March and 73 (12.2% ) in June, 2009. A total of 26 and 59 offspring snails were found respectively in April and June, 2009, with average density of 2.17 snails/m2 (26/12) and 4.92 snails/m2 (59/12) respectively. The exotic imported snails can survive and reproduce in water network regions. Further monitoring should be strengthened on the imported snails in these regions.

A Two-Temperature Model of the Intracluster Medium

NASA Astrophysics Data System (ADS)

Takizawa, Motokazu

1998-12-01

We investigate evolution of the intracluster medium (ICM), considering the relaxation process between the ions and electrons. According to the standard scenario of structure formation, the ICM is heated by the shock in the accretion flow to the gravitational potential well of the dark halo. The shock primarily heats the ions because the kinetic energy of an ion entering the shock is larger than that of an electron by the ratio of masses. Then the electrons and ions exchange the energy through Coulomb collisions and reach equilibrium. From simple order estimation we find that the region where the electron temperature is considerably lower than the ion temperature spreads out on a megaparsec scale. We then calculate the ion and electron temperature profiles by combining the adiabatic model of a two-temperature plasma by Fox & Loeb with spherically symmetric N-body and hydrodynamic simulations based on three different cosmological models. It is found that the electron temperature is about half the mean temperature at radii ~1 Mpc. This could lead to about a 50% underestimation in the total mass contained within ~1 Mpc when the electron temperature profiles are used. The polytropic indices of the electron temperature profiles are ~=1.5, whereas those of mean temperature are ~=1.3 for r >= 1 Mpc. This result is consistent both with the X-ray observations on electron temperature profiles and with some theoretical and numerical predictions about mean temperature profiles.

The Effects of CO2 Injection and Barrel Temperatures on the Physiochemical and Antioxidant Properties of Extruded Cereals

PubMed Central

Thin, Thazin; Myat, Lin; Ryu, Gi-Hyung

2016-01-01

The effects of CO2 injection and barrel temperatures on the physiochemical and antioxidant properties of extruded cereals (sorghum, barley, oats, and millet) were studied. Extrusion was carried out using a twin-screw extruder at different barrel temperatures (80, 110, and 140°C), CO2 injection (0 and 500 mL/min), screw speed of 200 rpm, and moisture content of 25%. Extrusion significantly increased the total flavonoid content (TFC) of extruded oats, and β-glucan and protein digestibility (PD) of extruded barley and oats. In contrast, there were significant reductions in 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity, PD of extruded sorghum and millet, as well as resistant starch (RS) of extruded sorghum and barley, and total phenolic content (TPC) of all extrudates, except extruded millet. At a barrel temperature of 140°C, TPC in extruded barley was significantly increased, and there was also an increase in DPPH and PD in extruded millet with or without CO2 injection. In contrast, at a barrel temperature of 140°C, the TPC of extruded sorghum decreased, TFC of extruded oats decreased, and at a barrel temperature of 110°C, PD of extruded sorghum without CO2 decreased. Some physical properties [expansion ratio (ER), specific length, piece density, color, and water absorption index] of the extrudates were significantly affected by the increase in barrel temperature. The CO2 injection significantly affected some physical properties (ER, specific length, piece density, water solubility index, and water absorption index), TPC, DPPH, β-glucan, and PD. In conclusion, extruded barley and millet had higher potential for making value added cereal-based foods than the other cereals. PMID:27752504

Characterizing the Chemical Stability of High Temperature Materials for Application in Extreme Environments

NASA Technical Reports Server (NTRS)

Opila, Elizabeth

2005-01-01

The chemical stability of high temperature materials must be known for use in the extreme environments of combustion applications. The characterization techniques available at NASA Glenn Research Center vary from fundamental thermodynamic property determination to material durability testing in actual engine environments. In this paper some of the unique techniques and facilities available at NASA Glenn will be reviewed. Multiple cell Knudsen effusion mass spectrometry is used to determine thermodynamic data by sampling gas species formed by reaction or equilibration in a Knudsen cell held in a vacuum. The transpiration technique can also be used to determine thermodynamic data of volatile species but at atmospheric pressures. Thermodynamic data in the Si-O-H(g) system were determined with this technique. Free Jet Sampling Mass Spectrometry can be used to study gas-solid interactions at a pressure of one atmosphere. Volatile Si(OH)4(g) was identified by this mass spectrometry technique. A High Pressure Burner Rig is used to expose high temperature materials in hydrocarbon-fueled combustion environments. Silicon carbide (SiC) volatility rates were measured in the burner rig as a function of total pressure, gas velocity and temperature. Finally, the Research Combustion Lab Rocket Test Cell is used to expose high temperature materials in hydrogen/oxygen rocket engine environments to assess material durability. SiC recession due to rocket engine exposures was measured as a function of oxidant/fuel ratio, temperature, and total pressure. The emphasis of the discussion for all techniques will be placed on experimental factors that must be controlled for accurate acquisition of results and reliable prediction of high temperature material chemical stability.

Measuring Poisson Ratios at Low Temperatures

NASA Technical Reports Server (NTRS)

Boozon, R. S.; Shepic, J. A.

1987-01-01

Simple extensometer ring measures bulges of specimens in compression. New method of measuring Poisson's ratio used on brittle ceramic materials at cryogenic temperatures. Extensometer ring encircles cylindrical specimen. Four strain gauges connected in fully active Wheatstone bridge self-temperature-compensating. Used at temperatures as low as liquid helium.

Demonstrating the limitations of line ratio temperature diagnostic using Fe X and Fe XIV spectral line intensity observations

NASA Technical Reports Server (NTRS)

Brickhouse, Nancy; Esser, Ruth; Habbal, Shadia R.

1995-01-01

The electron temperature in the inner corona can be derived from spectral line intensity measurements by comparing the ratio of the measured intensities of two spectral lines to the ratio calculated from theoretical models. In a homogeneous plasma the line ratio technique can be used for any two lines if the ratio of the intensities is independent of the density. The corona, however, is far from homogeneous. Even large coronal holes present at the solar poles at solar minimum can be partly or completely obscured by emission from hotter and denser surrounding regions. In this paper we investigate the effect of these surrounding regions on coronal hole temperatures. using daily intensity measurements at 1.15 Rs of the Fe XIV 5303 A and Fe X 6374 A spectral lines carried out at the National Solar Observatory at Sacramento Peak. We show that the temperatures derived using the line ratio technique for these two spectral lines can vary by more than 0.8 x 10(exp 6) K due to the contribution from surrounding regions. This example demonstrates the inadequacy of spectral lines with widely separate peak temperatures for temperature diagnostic.

Investigation on Two Forms of Temperature-Sensing Parameters for Fluorescence Intensity Ratio Thermometry Based on Thermal Coupled Theory.

PubMed

Jia, Mochen; Liu, Guofeng; Sun, Zhen; Fu, Zuoling; Xu, Weiguo

2018-02-05

Absolute temperature sensitivity (S a ) reflects the precision of sensors that belong to the same mechanism, whereas relative temperature sensitivity (S r ) is used to compare sensors from different mechanisms. For the fluorescence intensity ratio (FIR) thermometry based on two thermally coupled energy levels of one rare earth (RE) ion, we define a new ratio as the temperature-sensing parameter that can vary greatly with temperature in some circumstances, which can obtain higher S a without changing S r . Further discussion is made on the conditions under which these two forms of temperature-sensing parameters can be used to achieve higher S a for biomedical temperature sensing. Based on the new ratio as the temperature-sensing parameter, the S a and S r of the BaTiO 3 : 0.01%Pr 3+ , 8%Yb 3+ nanoparticles at 313 K reach as high as 0.1380 K -1 and 1.23% K -1 , respectively. Similarly, the S a and S r of the BaTiO 3 : 1%Er 3+ , 3%Yb 3+ nanoparticles at 313 K are as high as 0.0413 K -1 and 1.05% K -1 , respectively. By flexibly choosing the two ratios as the temperature-sensing parameter, higher S a can be obtained at the target temperature, which means higher precision for the FIR thermometers.

Optimization of the microwave-assisted extraction of phlorotannins from Saccharina japonica Aresch and evaluation of the inhibitory effects of phlorotannin-containing extracts on HepG2 cancer cells

NASA Astrophysics Data System (ADS)

He, Zhizhou; Chen, Yongshun; Chen, Yongheng; Liu, Haohuai; Yuan, Guanfu; Fan, Yaming; Chen, Kun

2013-09-01

The use of a microwave-assisted extraction (MAE) method for the extraction of phlorotannins from Saccharina japonica Aresch ( S. japonica) has been evaluated with particular emphasis on the influential parameters, including the ethanol concentration, solid/liquid ratio, extraction time, extraction temperature, and microwave power. The MAE procedure was optimized using single-factor design and orthogonal array design (OAD). The content of total phlorotannins in S. japonica was determined using a Folin-Ciocalteu (FC) assay. A maximum total phlorotannin content of 0.644 mg of phloroglucinol equivalent per gram of dry weight plant (mg PGE/g DW) was obtained using the optimized model, which included an ethanol concentration of 55%, solid/liquid ratio of 1:8, extraction time of 25 min, irradiation power of 400 W, and temperature of 60°C. Under similar conditions, the application of a conventional extraction method led to a lower phlorotannin yield of 0.585 mg PGE/g WD. These results demonstrated that the MAE approach provided better results for the extraction of phlorotannins from S. japonica and was a promising technique for the extraction of phenolic compounds from S. japonica and other materials. In addition, screening tests for the inhibitory activity showed that the phlorotannin-containing extracts significantly inhibited the growth of human hepatocellular carcinoma cells (HepG2) by inducing their apoptosis. The morphological changes that occurred during cell apoptosis were characterized using Hoechst33258 staining.

Development of Phaleria macrocarpa (Scheff.) Boerl Fruits Using Response Surface Methodology Focused on Phenolics, Flavonoids and Antioxidant Properties.

PubMed

Mohamed Mahzir, Khurul Ain; Abd Gani, Siti Salwa; Hasanah Zaidan, Uswatun; Halmi, Mohd Izuan Effendi

2018-03-22

In this study, the optimal conditions for the extraction of antioxidants from the Buah Mahkota Dewa fruit ( Phaleria macrocarpa) was determined by using Response Surface Methodology (RSM). The optimisation was applied using a Central Composite Design (CCD) to investigate the effect of three independent variables, namely extraction temperature (°C), extraction time (minutes) and extraction solvent to-feed ratio (% v / v ) on four responses: free radical scavenging activity (DPPH), ferric ion reducing power assay (FRAP), total phenolic content (TPC) and total flavonoid content (TFC). The optimal conditions for the antioxidants extraction were found to be 64 °C extraction temperature, 66 min extraction time and 75% v / v solvent to-feed ratio giving the highest percentage yields of DPPH, FRAP, TPC and TFC of 86.85%, 7.47%, 292.86 mg/g and 3.22 mg/g, respectively. Moreover, the data were subjected to Response Surface Methodology (RSM) and the results showed that the polynomial equations for all models were significant, did not show lack of fit, and presented adjusted determination coefficients ( R ²) above 99%, proving that the yield of phenolic, flavonoid and antioxidants activities obtained experimentally were close to the predicted values and the suitability of the model employed in RSM to optimise the extraction conditions. Hence, in this study, the fruit from P. macrocarpa could be considered to have strong antioxidant ability and can be used in various cosmeceutical or medicinal applications.

Effects of wildfires on ash Carbon, Nitrogen and C/N ratio in Mediterranean forests

NASA Astrophysics Data System (ADS)

Pereira, P.; Ubeda, X.; Martin, D. A.

2009-04-01

Carbon (C) and Nitrogen(N) are key nutrients in ecosystems health and the more affected by fire temperatures, because of their low temperatures of volatilization. After a wildfire, due higher temperatures reached, a great amount of C and N can be evacuated from the ecosystems and the percentage of C and N not vaporized is concentrated in ashes. Hence, the study of ash C and N is of major importance because will be linked with the capacity of ecosystem recuperation. The aim of this work is study the C, and C/N of three wildfires occurred in Mediterranean forests dominated by Quercus suber and Pinus pinea in Portugal. In the first wildfire, named "Quinta do Conde", we collected 30 samples, in the second, "Quinta da Areia", 32 samples and the third, "Casal do Sapo" 40 samples To estimate the consequences of wildfires in the parameters in study, we collected several samples of unburned litter near burned areas, composed by the same vegetation. The results showed that wildfires induced in % of Total Carbon (%TC) ashes content a non significantly reduction in Quinta do Conde plot (at a p<0,05) and significantly in Quinta da Areia plot (p<0.001) and Casal do Sapo plot (p<0.001). In % of Total Nitrogen (%TN) ashes content we observed in Quinta do Conde plot a significant increase (p<0.001), a non significant decrease in Quinta da Areia plot (at a p<0,05) and a significant reduce in Casal do Sapo plot (p<0.01). The The C/N ratio suffer a significant (p<0.001) reduction in Quinta do Conde and Quinta da Areia plots and at a p<0.01 in Casal do Sapo plot. In all parameters in study, wilfires induced a greater spatial variability, by the analysis of the Coefficient of Variation. Our tests effectuated in laboratory with samples collected near wildfires occurrence and exposed to the temperature gradient (150°, 200°, 250°, 300°, 350°, 400°, 450°, 500°, 550°C) fit with the results obtained. With temperature gradient, we identified a decrease of %TC ash content of Quercus suber samples and a rise until the 300°C in Pinus pinaster samples decreasing thereafter especially after the 400°C. In %TN we identified a rise in both species reducing abruptly at 450°C. C/N ratio decrease importantly after the 150°C. Theses results showed us that wildfires can have different effects C and N litter resources, depending on the severity and temperature reached. Crossing the results obtained in laboratory simulations with the samples collected in wildfires we will have an idea about the severity and temperature occurred in each wildfire. Overall, the lower severity were observed in Quinta do Conde plot and the higher in Casal do Sapo plot, being Quinta da Areia in a middle position. The C and N levels after a wildfire will determine the capacity of landscape recuperation and according the data obtained this will be higher in Quinta do Conde plot and lesser in Casal do Sapo plot. These hypothesis will be confirmed by field observation. Keywords: Carbon, Nitrogen, C/N ratio, wildfires, ashes, Quinta do Conde, Quinta da Areia, Casal do Sapo, Quercus suber, Pinus pinaster, Laboratory simulations, Severity, Landscape recuperation.

Fluoride geochemistry of thermal waters in Yellowstone National Park: I. Aqueous fluoride speciation

USGS Publications Warehouse

Deng, Y.; Nordstrom, D. Kirk; McCleskey, R. Blaine

2011-01-01

Thermal water samples from Yellowstone National Park (YNP) have a wide range of pH (1–10), temperature, and high concentrations of fluoride (up to 50 mg/l). High fluoride concentrations are found in waters with field pH higher than 6 (except those in Crater Hills) and temperatures higher than 50 °C based on data from more than 750 water samples covering most thermal areas in YNP from 1975 to 2008. In this study, more than 140 water samples from YNP collected in 2006–2009 were analyzed for free-fluoride activity by ion-selective electrode (ISE) method as an independent check on the reliability of fluoride speciation calculations. The free to total fluoride concentration ratio ranged from <1% at low pH values to >99% at high pH. The wide range in fluoride activity can be explained by strong complexing with H+ and Al3+ under acidic conditions and lack of complexing under basic conditions. Differences between the free-fluoride activities calculated with the WATEQ4F code and those measured by ISE were within 0.3–30% for more than 90% of samples at or above 10−6 molar, providing corroboration for chemical speciation models for a wide range of pH and chemistry of YNP thermal waters. Calculated speciation results show that free fluoride, F−, and major complexes (HF(aq)0">HF(aq)0, AlF2+, AlF2+">AlF2+and AlF30">AlF30) account for more than 95% of total fluoride. Occasionally, some complex species like AlF4-">AlF4-, FeF2+, FeF2+">FeF2+, MgF+ and BF2(OH)2-">BF2(OH)2- may comprise 1–10% when the concentrations of the appropriate components are high. According to the simulation results by PHREEQC and calculated results, the ratio of main fluoride species to total fluoride varies as a function of pH and the concentrations and ratios of F and Al.

Volcanic plume and bomb field masses from thermal infrared camera imagery

NASA Astrophysics Data System (ADS)

Harris, A. J. L.; Delle Donne, D.; Dehn, J.; Ripepe, M.; Worden, A. K.

2013-03-01

Masses erupted during normal explosions at Stromboli volcano (Italy) are notoriously difficult to measure. We present a method that uses thermal infrared video for cooling bomb fields to obtain the total power emitted by all hot particles emitted during an explosion. A given mass of magma (M) will emit a finite amount of thermal power, defined by M cp(Te-T0), cp and Te being magma specific heat capacity and temperature, and T0 being ambient temperature. We use this relation to convert the total power emitted by the bomb field to the mass required to generate that power. To do this we extract power flux curves for the field and integrate this through time to obtain total power (E). This is used to estimate mass (Q) in Q=E/cp(Te-T0). When applied to individual bombs we obtain masses of between 1 and 9 kg per bomb, or a volume of 970 and 6500 cm3. These volumes equate to spheres with diameters 12 and 27 cm. For the entire bomb field we obtain volumes of 7-28 m3. We calculate masses for 32 eruptions and obtain typical bomb masses of between 103 and 104 kg per eruption. In addition, we estimate that between 102 and 103 kg of gas and ash are emitted as part of a mixed plume of bombs, gas and ash. We identify two types of eruption on the basis of the erupted bomb masses and the ratio of the plume's gas-and-ash component to the bomb component. The first type is bomb-dominated, is characterized by bomb masses of 104 kg and has ash-gas/ bomb ratios of ˜0.02. The second type is ash-and-gas dominated, is characterized by erupted bomb masses of 103 kg and has ash-gas/bomb ratios of around one, and as high as two. There is no correlation between the quantity of bombs and quantity of gas-ash erupted. In addition, while source pressure for each explosion correlates with the quantity of gas and ash erupted, the mass of bombs emitted varies independently of pressure.

Dietary Supplementation of Chromium Can Alleviate Negative Impacts of Heat Stress on Performance, Carcass Yield, and Some Blood Hematology and Chemistry Indices of Growing Japanese Quail.

PubMed

El-Kholy, Mohamed Soliman; El-Hindawy, Mohamed Mohamed; Alagawany, Mahmoud; Abd El-Hack, Mohamed Ezzat; El-Sayed, Sabry Abd El-Gawad Abd El-Halim

2017-09-01

The main objective of this work was to investigate the impact of dietary chromium supplementation on growth indices, carcass yield, and some hematological and biochemical blood parameters of growing Japanese quails subjected to heat stress. A total of 360 unsexed 2-week-old Japanese quail chicks were used in a 2 × 3 factorial arrangement that had two ambient temperatures (23 ± 2 and 33 ± 2 °C) and three dietary chromium (0.00, 500, and 1000 μg Cr/kg diet as chromium picolinate). For induction of heat stress, the room temperature was set at 33 ± 2 °C from 2 to 6 weeks of age. Results showed that body weight, body weight gain, and feed intake were decreased for birds subjected to heat stress condition during 2 to 4 and 2 to 6 weeks of age. Feed conversion was not significantly (P > 0.05) affected by high ambient temperature throughout the experiment. Carcass, dressing, liver, and heart percentages were not influenced by the ambient temperature or dietary chromium or their combinations. Significant temperature × chromium combinations were observed for hemoglobin value (P = 0.025) and packed cell volume (P = 0.001). Cholesterol and glucose in plasma were increased (P = 0.004 or 0.022) in quails subjected to heat stress condition. Plasma measurements of total proteins, albumin, globulin, lipids, glucose, and A/G ratio of quail chicks were not influenced (P > 0.05) by chromium, while cholesterol was increased with increasing chromium level (P = 0.033). High ambient temperature or dietary chromium levels or their interactions did not (P > 0.05) affect plasma levels of aspartate transaminase (AST), alanine transaminase (ALT), triiodothyronine (T3), thyroxin (T4), or T3/T4 ratio of growing quails. From these observations, it can be concluded that dietary chromium supplementation of growing Japanese quail subjected to heat stress condition could beneficially affect growth performance and carcasses, as well as modulate the hematological and biochemical blood parameters, probably through modulating stress status.

Characterisation of diesel particulate emission from engines using commercial diesel and biofuels

NASA Astrophysics Data System (ADS)

Ajtai, T.; Pintér, M.; Utry, N.; Kiss-Albert, G.; Gulyás, G.; Pusztai, P.; Puskás, R.; Bereczky, Á.; Szabados, Gy.; Szabó, G.; Kónya, Z.; Bozóki, Z.

2016-06-01

In this paper, the number concentration and the size distribution of diluted diesel exhaust particulate matter were measured at three different engine operating points in the speed-load range of the engine as follows: 1600 rpm; 50% load, 1900 rpm; 25% load, 1900 rpm; 75% load, adopted from the UN ECE Vehicle Regulation no. 49 (Revision 2) test protocol using pure diesel and biodiesel fuels, as well as their controlled blends. The emitted particulate assembly had lognormal size distribution in the accumulation mode regardless of the engine operational condition and the type of fuel. The total number and volume concentration emitted by the diesel engine decreased with increasing revolution per minute and rated torque in case of all the fuel types. The mixing ratio of the fuels did not linearly affect the total emission but had a minimum at 75% biodiesel content. We also studied the thermal evolution of the emitted particulates using a specially designed thermodenuder (TD) heated at specific temperatures (50 °C, 120 °C, and 250 °C). The first transition, when the temperature was increased from 50 °C to 120 °C resulted in lower number concentrations with small relative shifts of the peak position. However, in case of the second transition, when the temperature reached 250 °C the individual volatile particulates adsorbed onto the surface of soot particles were completely or partly vaporised resulting in lower total number concentrations with a substantial shift in peak position.

Performance and emission characteristics of swirl-can combustors to near-stoichiometric fuel-air ratio

NASA Technical Reports Server (NTRS)

Diehl, L. A.; Trout, A. M.

1976-01-01

Emissions and performance characteristics were determined for two full annular swirl-can combustors operated to near stoichiometric fuel-air ratio. Test condition variations were as follows: combustor inlet-air temperatures, 589, 756, 839, and 894 K; reference velocities, 24 to 37 meters per second; inlet pressure, 62 newtons per square centimeter; and fuel-air ratios, 0.015 to 0.065. The combustor average exit temperature and combustor efficiency were calculated from the combustor exhaust gas composition. For fuel-air ratios greater than 0.04, the combustion efficiency decreased with increasing fuel-air ratios in a near-linear manner. Increasing the combustor inlet air temperature tended to offset this decrease. Maximum oxides of nitrogen emission indices occurred at intermediate fuel-air ratios and were dependent on combustor design. Carbon monoxide levels were extremely high and were the primary cause of poor combustion efficiency at the higher fuel-air ratios. Unburned hydrocarbons were low for all test conditions. For high fuel-air ratios SAE smoke numbers greater than 25 were produced, except at the highest inlet-air temperatures.

Comparison of the effect of two damper sizes on the performance of a low-solidity axial-flow transonic compressor rotor

NASA Technical Reports Server (NTRS)

Lewis, G. W., Jr.; Urasek, D. C.

1972-01-01

The experimental performance of a 20-inch-diameter axial-flow transonic compressor rotor with small dampers is presented. The compressor rotor was tested earlier with large dampers which were twice in size, and comparisons of overall performance and radial distributions of selected flow and performance parameters are made. The rotor with small dampers experienced lower losses in the damper region which resulted in locally higher values of temperature rise efficiency and total pressure ratio. However, there was no appreciable effect on overall efficiency and pressure ratio. A greater stall margin was measured for the rotor with small dampers at design speed, but at 70 and 90 percent of design speed the rotor with large dampers had somewhat greater flow range.

Optical spectrophotometry of Wolf-Rayet galaxies

NASA Technical Reports Server (NTRS)

Vacca, William D.; Conti, Peter S.

1992-01-01

We have obtained long-slit optical spectra of 10 Wolf-Rayet galaxies and four other starburst galaxies. Using the nebular emission lines we have determined the electron temperatures, electron densities, extinctions, oxygen abundances, mass of ionized hydrogen, and numbers of ionizing photons due to hot stars in these galaxies. The various forbidden line ratios clearly indicate a stellar origin for the emission-line spectrum. From the flux of the broad He II 4686 A emission feature we have estimated the number of Wolf-Rayet stars present. We have accounted for the contribution of these stars to the total ionizing flux and have calculated the ratio of the number of these stars to the number of O stars. Wolf-Rayet galaxies are among the youngest examples of the starburst phenomenon, which we observed at a propitious moment.

Explosion characteristics of LPG-air mixtures in closed vessels.

PubMed

Razus, Domnina; Brinzea, Venera; Mitu, Maria; Oancea, D

2009-06-15

The experimental study of explosive combustion of LPG (liquefied petroleum gas)-air mixtures at ambient initial temperature was performed in two closed vessels with central ignition, at various total initial pressures within 0.3-1.3bar and various fuel/air ratios, within the flammability limits. The transient pressure-time records were used to determine several explosion characteristics of LPG-air: the peak explosion pressure, the explosion time (the time necessary to reach the peak pressure), the maximum rate of pressure rise and the severity factor. All explosion parameters are strongly dependent on initial pressure of fuel-air mixture and on fuel/air ratio. The explosion characteristics of LPG-air mixtures are discussed in comparison with data referring to the main components of LPG: propane and butane, obtained in identical conditions.

Heritable Variation for Sex Ratio under Environmental Sex Determination in the Common Snapping Turtle (Chelydra Serpentina)

PubMed Central

Janzen, F. J.

1992-01-01

The magnitude of quantitative genetic variation for primary sex ratio was measured in families extracted from a natural population of the common snapping turtle (Chelydra serpentina), which possesses temperature-dependent sex determination (TSD). Eggs were incubated at three temperatures that produced mixed sex ratios. This experimental design provided estimates of the heritability of sex ratio in multiple environments and a test of the hypothesis that genotype X environment (G X E) interactions may be maintaining genetic variation for sex ratio in this population of C. serpentina. Substantial quantitative genetic variation for primary sex ratio was detected in all experimental treatments. These results in conjunction with the occurrence of TSD in this species provide support for three critical assumptions of Fisher's theory for the microevolution of sex ratio. There were statistically significant effects of family and incubation temperature on sex ratio, but no significant interaction was observed. Estimates of the genetic correlations of sex ratio across environments were highly positive and essentially indistinguishable from +1. These latter two findings suggest that G X E interaction is not the mechanism maintaining genetic variation for sex ratio in this system. Finally, although substantial heritable variation exists for primary sex ratio of C. serpentina under constant temperatures, estimates of the effective heritability of primary sex ratio in nature are approximately an order of magnitude smaller. Small effective heritability and a long generation time in C. serpentina imply that evolution of sex ratios would be slow even in response to strong selection by, among other potential agents, any rapid and/or substantial shifts in local temperatures, including those produced by changes in the global climate. PMID:1592234

Separating Iso-Propanol-Toluene mixture by azeotropic distillation

NASA Astrophysics Data System (ADS)

Iqbal, Asma; Ahmad, Syed Akhlaq

2018-05-01

The separation of Iso-Propanol-Toluene azeotropic mixture using Acetone as an entrainer has been simulated on Aspen Plus software package using rigorous methods. Calculations of the vapor-liquid equilibrium for the binary system are done using UNIQUAC-RK model which gives a good agreement with the experimental data reported in literature. The effects of the Reflux ratio (RR), distillate-to-feed molar ratio (D/F), feed stage, solvent feed stage, Total no. of stages and solvent feed temperature on the product purities and recoveries are studied to obtain their optimum values that give the maximum purity and recovery of products. The configuration consists of 20 theoretical stages with an equimolar feed of binary mixture. The desired separation of binary mixture has been achieved at the feed stage and an entrainer feeding stage of 15 and 12 respectively with the reflux ratios of 2.5 and 4.0, and D/F ratio of 0.75 and 0.54 respectively in the two columns. The simulation results thus obtained are useful to setup the optimal column configuration of the azeotropic distillation process.

Comparative Analysis of Alternative Spectral Bands of CO2 and O2 for the Sensing of CO2 Mixing Ratios

NASA Technical Reports Server (NTRS)

Pliutau, Denis; Prasad, Narasimha S.

2013-01-01

We performed comparative studies to establish favorable spectral regions and measurement wavelength combinations in alternative bands of CO2 and O2, for the sensing of CO2 mixing ratios (XCO2) in missions such as ASCENDS. The analysis employed several simulation approaches including separate layers calculations based on pre-analyzed atmospheric data from the modern-era retrospective analysis for research and applications (MERRA), and the line-byline radiative transfer model (LBLRTM) to obtain achievable accuracy estimates as a function of altitude and for the total path over an annual span of variations in atmospheric parameters. Separate layer error estimates also allowed investigation of the uncertainties in the weighting functions at varying altitudes and atmospheric conditions. The parameters influencing the measurement accuracy were analyzed independently and included temperature sensitivity, water vapor interferences, selection of favorable weighting functions, excitations wavelength stabilities and other factors. The results were used to identify favorable spectral regions and combinations of on / off line wavelengths leading to reductions in interferences and the improved total accuracy.

14C/C measurements support Andreev's internode method to determine lichen growth rates in Cladina stygia (Fr.) Ahti

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

Holt, E; Bench, G

2007-12-05

Growth rates and the ability to date an organism can greatly contribute to understanding its population biology and community dynamics. 1n 1954, Andreev proposed a method to date Cladina, a fruticose lichen, using total thallus length and number of internodes. No research, however, has demonstrated the reliability of this technique or compared its estimates to those derived by other means. In this study, we demonstrate the utility of {sup 14}C/C ratios to determine lichen age and growth rate in Cladina stygia (Fr.) Ahti collected from northwestern Alaska, USA. The average growth rate using {sup 14}C/C ratios was 6.5 mm {center_dot}more » yr{sup -1}, which was not significantly different from growth rates derived by Andreev's internode method (average = 6.2 mm {center_dot} yr{sup -1}); thus, suggesting the reliability of Andreev's simple field method for dating lichens. In addition, we found lichen growth rates appeared to differ with geographic location, yet did not seem related to ambient temperature and total precipitation.« less

Plasmaspheric H+, He+, O+, He++, and O++ Densities and Temperatures

NASA Technical Reports Server (NTRS)

Gallagher, D. L.; Craven, P. D.; Comfort H.

2013-01-01

Thermal plasmaspheric densities and temperatures for five ion species have recently become available, even though these quantities were derived some time ago from the Retarding Ion Mass Spectrometer onboard the Dynamics Explorer 1 satellite over the years 1981-1984. The quantitative properties will be presented. Densities are found to have one behavior with lessor statistical variation below about L=2 and another with much greater variability above that Lshell. Temperatures also have a behavior difference between low and higher L-values. The density ratio He++/H+ is the best behaved with values of about 0.2% that slightly increase with increasing L. Unlike the He+/H+ density ratio that on average decreases with increasing Lvalue, the O+/H+ and O++/H+ density ratios have decreasing values below about L=2 and increasing average ratios at higher L-values. Hydrogen ion temperatures range from about 0.2 eV to several 10s of eV for a few measurements, although the bulk of the observations are of temperatures below 3 eV, again increasing with L-value. The temperature ratios of He+/H+ are tightly ordered around 1.0 except for the middle plasmasphere between L=3.5 and 4.5 where He+ temperatures can be significantly higher. The temperatures of He++, O+, and O++ are consistently higher than H+.

Plasmaspheric H+, He+, He++, O+, and O++ Densities and Temperatures

NASA Technical Reports Server (NTRS)

Gallagher, G. L.; Craven, P. D.; Comfort, R. H.

2013-01-01

Thermal plasmaspheric densities and temperatures for five ion species have recently become available, even though these quantities were derived some time ago from the Retarding Ion Mass Spectrometer onboard the Dynamics Explorer 1 satellite over the years 1981-1984. The quantitative properties will be presented. Densities are found to have one behavior with lessor statistical variation below about L=2 and another with much greater variability above that Lshell. Temperatures also have a behavior difference between low and higher L-values. The density ratio He++/H+ is the best behaved with values of about 0.2% that slightly increase with increasing L. Unlike the He+/H+ density ratio that on average decreases with increasing Lvalue, the O+/H+ and O++/H+ density ratios have decreasing values below about L=2 and increasing average ratios at higher L-values. Hydrogen ion temperatures range from about 0.2 eV to several 10s of eV for a few measurements, although the bulk of the observations are of temperatures below 3 eV, again increasing with L-value. The temperature ratios of He+/H+ are tightly ordered around 1.0 except for the middle plasmasphere between L=3.5 and 4.5 where He+ temperatures can be significantly higher. The temperatures of He++, O+, and O++ are consistently higher than H+.

A Determination of the Ratio of the Zinc Freezing Point to the Tin Freezing Point by Noise Thermometry

NASA Astrophysics Data System (ADS)

Labenski, J. R.; Tew, W. L.; Benz, S. P.; Nam, S. W.; Dresselhaus, P.

2008-02-01

A Johnson-noise thermometer (JNT) has been used with a quantized voltage noise source (QVNS), as a calculable reference to determine the ratio of temperatures near the Zn freezing point to those near the Sn freezing point. The temperatures are derived in a series of separate measurements comparing the synthesized noise power from the QVNS with that of Johnson noise from a known resistance. The synthesized noise power is digitally programed to match the thermal noise powers at both temperatures and provides the principle means of scaling the temperatures. This produces a relatively flat spectrum for the ratio of spectral noise densities, which is close to unity in the low-frequency limit. The data are analyzed as relative spectral ratios over the 4.8 to 450 kHz range averaged over a 3.2 kHz bandwidth. A three-parameter model is used to account for differences in time constants that are inherently temperature dependent. A drift effect of approximately -6 μK·K-1 per day is observed in the results, and an empirical correction is applied to yield a relative difference in temperature ratios of -11.5 ± 43 μK·K-1 with respect to the ratio of temperatures assigned on the International Temperature Scale of 1990 (ITS-90). When these noise thermometry results are combined with results from acoustic gas thermometry at temperatures near the Sn freezing point, a value of T - T 90 = 7 ± 30 mK for the Zn freezing point is derived.

Influence of Layer Thickness, Raster Angle, Deformation Temperature and Recovery Temperature on the Shape-Memory Effect of 3D-Printed Polylactic Acid Samples

PubMed Central

Wu, Wenzheng; Ye, Wenli; Wu, Zichao; Geng, Peng; Wang, Yulei; Zhao, Ji

2017-01-01

The success of the 3D-printing process depends upon the proper selection of process parameters. However, the majority of current related studies focus on the influence of process parameters on the mechanical properties of the parts. The influence of process parameters on the shape-memory effect has been little studied. This study used the orthogonal experimental design method to evaluate the influence of the layer thickness H, raster angle θ, deformation temperature Td and recovery temperature Tr on the shape-recovery ratio Rr and maximum shape-recovery rate Vm of 3D-printed polylactic acid (PLA). The order and contribution of every experimental factor on the target index were determined by range analysis and ANOVA, respectively. The experimental results indicated that the recovery temperature exerted the greatest effect with a variance ratio of 416.10, whereas the layer thickness exerted the smallest effect on the shape-recovery ratio with a variance ratio of 4.902. The recovery temperature exerted the most significant effect on the maximum shape-recovery rate with the highest variance ratio of 1049.50, whereas the raster angle exerted the minimum effect with a variance ratio of 27.163. The results showed that the shape-memory effect of 3D-printed PLA parts depended strongly on recovery temperature, and depended more weakly on the deformation temperature and 3D-printing parameters. PMID:28825617

Heavy Element Abundances in NGC 5846

NASA Technical Reports Server (NTRS)

Jones, Christine

2000-01-01

In this paper we analyze the diffuse X-ray coronae surrounding the elliptical galaxy NGC 5846, combining measurements from two observatories, ROSAT and the Advanced Satellite for Cosmology and Astrophysics. We map the gas temperature distribution and find a central cool region within an approximately isothermal gas halo extending to a radius of about 50 kpc and evidence for a temperature decrease at larger radii. With a radially falling temperature profile, the total mass converges to (9.6 +/- 1.0) x 10(exp 12) solar mass at 230 kpc radius. This corresponds to a total mass to blue light ratio of 53 +/- 5 solar mass/solar luminosity. As in other early type galaxies, the gas mass is only a few percent of the total mass. Using the spectroscopic measurements, we also derive radial distributions for the heavy elements silicon and iron and find that the abundances of both decrease with galaxy radius. The mass ratio of Si to Fe lies between the theoretical predictions for element production in SN Ia and SN II, suggesting an important role for SN Ia, as well as SN II, for gas enrichment in ellipticals. Using the 2 SN la yield of Si, we set an upper limit of 0.012 h(sup 2, sub 50) solar neutrino units (SNU) for the SN Ia rate at radii >50 kpc, which is independent of possible uncertainties in the iron L-shell modeling. We compare our observations with the theoretical predictions for the chemical evolution of ellipticals. We conclude that the metal content in stars, if explained by the star formation duration, requires a significant decline in the duration of star formation with galaxy radius, ranging from 1 Gyr at the center to 0.01 Gyr at 100 kpc radius. Alternatively, the decline in metallicity with galaxy radius may be caused by a similar drop with radius in the efficiency of star formation. Based on the Si and Fe measurements presented in this paper, we conclude that the latter scenario is preferred unless a dependence of the SN Ia rate on stellar metallicity is invoked.

Intercellular Distribution of Glutathione Synthesis in Maize Leaves and Its Response to Short-Term Chilling1

PubMed Central

Gómez, Leonardo D.; Vanacker, Hélène; Buchner, Peter; Noctor, Graham; Foyer, Christine H.

2004-01-01

To investigate the intercellular control of glutathione synthesis and its influence on leaf redox state in response to short-term chilling, genes encoding γ-glutamylcysteine synthetase (γ-ECS) and glutathione synthetase (GSH-S) were cloned from maize (Zea mays) and specific antibodies produced. These tools were used to provide the first information on the intercellular distribution of γ-ECS and GSH-S transcript and protein in maize leaves, in both optimal conditions and chilling stress. A 2-d exposure to low growth temperatures (chill) had no effect on leaf phenotype, whereas return to optimal temperatures (recovery) caused extensive leaf bleaching. The chill did not affect total leaf GSH-S transcripts but strongly induced γ-ECS mRNA, an effect reversed during recovery. The chilling-induced increase in γ-ECS transcripts was not accompanied by enhanced total leaf γ-ECS protein or extractable activity. In situ hybridization and immunolocalization of leaf sections showed that γ-ECS and GSH-S transcripts and proteins were found in both the bundle sheath (BS) and the mesophyll cells under optimal conditions. Chilling increased γ-ECS transcript and protein in the BS but not in the mesophyll cells. Increased BS γ-ECS was correlated with a 2-fold increase in both leaf Cys and γ-glutamylcysteine, but leaf total glutathione significantly increased only in the recovery period, when the reduced glutathione to glutathione disulfide ratio decreased 3-fold. Thus, while there was a specific increase in the potential contribution of the BS cells to glutathione synthesis during chilling, it did not result in enhanced leaf glutathione accumulation at low temperatures. Return to optimal temperatures allowed glutathione to increase, particularly glutathione disulfide, and this was associated with leaf chlorosis. PMID:15047902

Correction analysis for a supersonic water cooled total temperature probe tested to 1370 K

NASA Technical Reports Server (NTRS)

Lagen, Nicholas T.; Seiner, John M.

1991-01-01

The authors address the thermal analysis of a water cooled supersonic total temperature probe tested in a Mach 2 flow, up to 1366 K total temperature. The goal of this experiment was the determination of high-temperature supersonic jet mean flow temperatures. An 8.99 cm exit diameter water cooled nozzle was used in the tests. It was designed for exit Mach 2 at 1366 K exit total temperature. Data along the jet centerline were obtained for total temperatures of 755 K, 1089 K, and 1366 K. The data from the total temperature probe were affected by the water coolant. The probe was tested through a range of temperatures between 755 K and 1366 K with and without the cooling system turned on. The results were used to develop a relationship between the indicated thermocouple bead temperature and the freestream total temperature. The analysis and calculated temperatures are presented.

The role of phosphate additive in stabilization of sulphuric-acid-based vanadium(V) electrolyte for all-vanadium redox-flow batteries

NASA Astrophysics Data System (ADS)

Roznyatovskaya, Nataliya V.; Roznyatovsky, Vitaly A.; Höhne, Carl-Christoph; Fühl, Matthias; Gerber, Tobias; Küttinger, Michael; Noack, Jens; Fischer, Peter; Pinkwart, Karsten; Tübke, Jens

2017-09-01

Catholyte in all-vanadium redox-flow battery (VRFB) which consists of vanadium salts dissolved in sulphuric acid is known to be stabilized by phosphoric acid to slow down the thermal aging at temperatures higher than 40 °C. To reveal the role of phosphoric acid, the thermally-induced aggregation is investigated using variable-temperature 51V, 31P, 17O, 1H nuclear magnetic resonance (NMR) spectroscopy and dynamic light scattering (DLS). The results indicate that the thermal stabilization of vanadium(V) electrolyte is attained by the involvement of monomeric and dimeric vanadium(V) species in the reaction with phosphoric acid which is concurrent to the formation of neutral hydroxo-aqua vanadium(V) precipitation precursor. The dimers are stabilized by counter ions due to association reaction or if such stabilization is not possible, precipitation of vanadium pentoxide is favored. The evolution of particles size distributions at 50 °C in electrolyte samples containing 1.6 M vanadium and 4.0 M total sulphate and the pathways of precipitate formation are discussed. The optimal total phosphate concentration is found to be of 0.15 M. However, the induction time is assumed to be dependent not only on the total phosphate concentrations, but also on the ratio of total vanadium(V) to sulphate concentrations.

Thermosensitive period of sex determination in the coral-reef damselfish Acanthochromis polyacanthus and the implications of projected ocean warming

NASA Astrophysics Data System (ADS)

Rodgers, G. G.; Donelson, J. M.; Munday, P. L.

2017-03-01

Higher temperatures associated with climate change have the potential to significantly alter the population sex ratio of species with temperature-dependent sex determination. Whether or not elevated temperature affects sex determination depends on both the absolute temperature experienced and the stage of development at which the thermal conditions occur. We explored the importance of exposure timing during early development in the coral reef fish, Acanthochromis polyacanthus, by increasing water temperature 1.5 or 3 °C above the summer average (28.5 °C) at different stages of development. We also measured the effect of treatment temperature on fish size and condition, in order to gauge how the thermal threshold for sex-ratio bias may compare with other commonly considered physiological metrics. Increasing grow-out temperature from 28.5 to 30 °C had no effect on the sex ratio of offspring, whereas an increase to 31.5 °C (+3 °C) produced a strong male bias (average 90%). The thermosensitive period for this species lasted between 25 and 60 d post hatching, with the bias in sex ratio greater the earlier that fish experienced warm conditions. Temperatures high enough to bias the sex ratio are likely to be seen first during late summer (January and February) and would affect clutches produced late in the breeding season. There was no change to fish condition in response to temperature; however, the two higher temperature treatments produced significantly smaller fish at sampling. Clutches produced early in the season could buffer the population from a skewed sex ratio, as their development will remain below the thermal threshold; however, continued ocean warming could mean that clutches produced earlier in the breeding season would also be affected in the longer term. A skewed sex ratio could be detrimental to population viability by reducing the number of females in the breeding population.

Effects of Pouring Temperature and Electromagnetic Stirring on Porosity and Mechanical Properties of A357 Aluminum Alloy Rheo-Diecasting

NASA Astrophysics Data System (ADS)

Guo, An; Zhao, Junwen; Xu, Chao; Li, Hu; Han, Jing; Zhang, Xu

2018-05-01

Semisolid slurry of A357 aluminum alloy was prepared using a temperature-controllable electromagnetic stirrer and rheo-diecast at different temperatures. The effects of pouring temperature and electromagnetic stirring (EMS) on the porosity in rheo-diecast samples, as well as the relation between porosity and mechanical properties, were investigated. The results show that pouring temperature and EMS had minor influences on rheo-diecast microstructure but marked influence on the porosity. With decreasing slurry pouring temperature, the porosity decreased first and then increased, whereas the maximum pore ratio (ratio of shape factor to diameter of the largest pore) increased first and then decreased. The maximum pore ratio determines the level of tensile strength and elongation, and higher mechanical properties can be obtained with smaller and rounder pores in samples. The mechanical properties of the rheo-diecast samples increased linearly with increasing maximum pore ratio. The maximum pore ratio was 1.43 µm-1, and the minimum porosity level was 0.37% under EMS condition for the rheo-diecast samples obtained at a pouring temperature of 608 °C. With this porosity condition, the maximum tensile strength and elongation were achieved at 274 MPa and 4.9%, respectively. It was also revealed that EMS improves mechanical properties by reduction in porosity and an increase in maximum pore ratio.

Co-composting of two-phase olive-mill pomace and poultry manure with tomato harvest stalks.

PubMed

Sülük, Kemal; Tosun, İsmail; Ekinci, Kamil

2017-04-01

In this study, two-phase olive-mill pomace with poultry manure and chopped tomato harvest stalks were composted at different initial carbon/nitrogen (C/N) ratios with fixed free air space of 35%. Composting experiment was carried out in the 15 aerobic reactors made of stainless steel and was monitored for 28 days. During the composting process, temperature, moisture content, organic matter (OM), pH, electrical conductivity, oxygen and carbon dioxide concentrations, total carbon, total nitrogen, ammonium nitrogen ([Formula: see text]), nitrate nitrogen ([Formula: see text]), and total phosphorus were monitored. Compost mass and volume changes were determined at the beginning, during remixings, and at the end of composting. While the stabilization period took less time for the mixtures containing a high amount of poultry manure, the mixtures having the high portion of two-phase olive-mill pomace took a longer time due to the structure of olive stone and its lignin content. Dry matter loss (range: 18.1-34.0%.) in the mixtures increased with an increase in the share of poultry manure and tomato stalks in the initial mixture. OM loss (range: 21.7-46.1%) for tomato stalks (measured separately) during composting increased due to an increase in the ratio of poultry manure in the initial mixtures.

A numerical study on the non-Boussinesq effect in the natural convection in horizontal annulus

NASA Astrophysics Data System (ADS)

Zhang, Yu; Cao, Yuhui

2018-04-01

In the present study, the non-Boussinesq effect in the thermal convection in an air-filled horizontal concentric annulus is studied numerically by using the variable property-based lattice Boltzmann flux solver (VPLBFS), with the radial temperature difference ratio of 1.0, the radius ratio of 2.0, and the Rayleigh number in the range 104 ≤ Ra ≤ 106. Several solutions are obtained by using the standard form or simplified versions of the VPLBFS, including the real solution with the total variation in fluid properties considered, named as the variable property solution (VPS), the constant property solution (CPS) based on the Boussinesq approximation, the solution with variable dynamic viscosity (VVS), the solution based on the partial Boussinesq approximation (PBAS), the solution with variable thermal conductivity (VCS) and the solution with variable fluid density (VDS). The discrepancy between these solutions is analyzed to illuminate the influence of the non-Boussinesq effects induced by partial or total variation in fluid properties on flow instability behaviors and heat transfer characteristics. The present study reveals the complicated flow instability behavior under non-Boussinesq conditions and its tight association with heat transfer characteristics. Also, it demonstrates the necessity of considering the integral effect of the total variation in fluid properties and highlights the essential role of the fluid density variation.

Lake Roosevelt Fisheries Evaluation Program; Limnological and Fisheries Monitoring, Annual Report 2000.

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

Lee, Chuck; Scofield, Ben; Pavlik, Deanne

2003-03-01

A slightly dryer than normal year yielded flows in Lake Roosevelt that were essentially equal to the past ten year average. Annual mean inflow and outflow were 3,160.3 m3/s and 3,063.4 m3/s respectively. Mean reservoir elevation was 387.2 m above sea level at the Grand Coulee Dam forebay. The forebay elevation was below the mean elevation for a total of 168 days. During the first half of the 2000 forebay elevation changed at a rate of 0.121 m/d and during the last half changed at a rate of 0.208 m/d. The higher rate of elevation change earlier in the yearmore » is due to the drawdown to accommodate spring runoff. Mean annual water retention time was 40 days. Annual mean total dissolved gas was 108%. Total dissolved gas was greatest at upriver locations (110% = US/Canada Border annual mean) and decreased moving toward Grand Coulee Dam (106% = Grand Coulee Dam Forebay annual mean). Total dissolved gas was greatest in May (122% reservoir wide monthly mean). Gas bubble trauma was observed in 16 fish primarily largescale suckers and was low in severity. Reservoir wide mean temperatures were greatest in August (19.5 C) and lowest in January (5.5 C). The Spokane River and Sanpoil River Arms experienced higher temperatures than the mainstem reservoir. Brief stratification was observed at the Sanpoil River shore location in July. Warm water temperatures in the Spokane Arm contributed to low dissolved oxygen concentrations in August (2.6 mg/L at 33 m). However, decomposition of summer algal biomass was likely the main cause of depressed dissolved oxygen concentrations. Otherwise, dissolved oxygen profiles were relatively uniform throughout the water column across other sampling locations. Annual mean Secchi depth throughout the reservoir was 5.7 m. Nutrient concentrations were generally low, however, annual mean total phosphorus (0.016 mg/L) was in the mesotrophic range. Annual mean total nitrogen was in the meso-oligotrophic range. Total nitrogen to total phosphorus ratios were large (31:1 annual mean) likely indicating phosphorus limitations to phytoplankton.« less

Effects of Variable Aspect-Ratio Inclusions on the Electrical Impedance of an Alumina Zirconia Composite at Intermediate Temperatures

NASA Technical Reports Server (NTRS)

Goldsby, Jon C.

2010-01-01

A series of alumina-yttria-stabilized zirconia composites containing either a high aspect ratio (5 and 30 mol%) hexagonal platelet alumina or an alumina low aspect ratio (5 and 30 mol%) spherical particulate was used to determine the effect of the aspect ratio on the temperature-dependent impedance of the composite material. The highest impedance across the temperature range of 373 to 1073 K is attributed to the grain boundary of the hexagonal platelet second phase in this alumina zirconia composite.

77 FR 47905 - Self-Regulatory Organizations; NYSE Arca, Inc.; Notice of Filing and Immediate Effectiveness of...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-08-10

...-or-Cancel orders, and (3) maintain a ratio of executed liquidity adding volume-to-total volume of... of CADV, ratio of cancelled orders to total orders and ratio of executed liquidity adding volume-to... ratio of executed liquidity adding volume to total volume of greater than 80%, which is the same ratio...

Socioeconomic factors outweigh climate in the regional difference of suicide death rate in Taiwan.

PubMed

Tsai, Jui-Feng

2010-09-30

The present study explored both socioeconomic and climatic factors to obtain a more comprehensive view of the asymmetric regional suicide death rate during 1998-2006 in Taiwan. The annual suicide death rate, population and meteorological data from 19 cities/counties in Taiwan were analysed by multiple regression. Five socioeconomic (sex ratio, no spouse, aged, unemployment and low income) and three climatic (temperature, rainfall and sunshine) factors were identified as significant, explaining 59.0% of the variance in the total suicide death rate. 'Without spouse' and 'aged' were associated with the highest risk, while 'low income with financial aids' was strongly protective. The most influential climatic factor was 'temperature,' which was negatively correlated with suicide. 'Sunshine' was positively associated with suicide. The socioeconomic and climatic factors contributed 52.7% and 6.8%, respectively, to the variance of the total suicide death rate. Limitations of the study included the fact that no individual events were considered, the study was of relatively short duration and it was confined to the territory of Taiwan. Socioeconomic factors outweighed climatic factors in explaining regional differences in the suicide death rate in Taiwan. Temperature weighed more than sunshine. 'Thermotherapy' seems more clinically relevant than the popular light therapy, at least in Taiwan. Copyright © 2008 Elsevier Ltd. All rights reserved.

Microorganism-regulated mechanisms of temperature effects on the performance of anaerobic digestion.

PubMed

Lin, Qiang; He, Guihua; Rui, Junpeng; Fang, Xiaoyu; Tao, Yong; Li, Jiabao; Li, Xiangzhen

2016-06-03

Temperature is an important factor determining the performance and stability of the anaerobic digestion process. However, the microorganism-regulated mechanisms of temperature effects on the performance of anaerobic digestion systems remain further elusive. To address this issue, we investigated the changes in composition, diversity and activities of microbial communities under temperature gradient from 25 to 55 °C using 16S rRNA gene amplicon sequencing approach based on genomic DNA (refer to as "16S rDNA") and total RNA (refer to as "16S rRNA"). Microbial community structure and activities changed dramatically along the temperature gradient, which corresponded to the variations in digestion performance (e.g., daily CH4 production, total biogas production and volatile fatty acids concentration). The ratios of 16S rRNA to 16S rDNA of microbial taxa, as an indicator of the potentially relative activities in situ, and whole activities of microbial community assessed by the similarity between microbial community based on 16S rDNA and rRNA, varied strongly along the temperature gradient, reflecting different metabolic activities. The daily CH4 production increased with temperature from 25 to 50 °C and declined at 55 °C. Among all the examined microbial properties, the whole activities of microbial community and alpha-diversity indices of both microbial communities and potentially relative activities showed highest correlations to the performance. The whole activities of microbial community and alpha-diversity indices of both microbial communities and potentially relative activities were sensitive indicators for the performance of anaerobic digestion systems under temperature gradient, while beta-diversity could predict functional differences. Microorganism-regulated mechanisms of temperature effects on anaerobic digestion performance were likely realized through increasing alpha-diversity of both microbial communities and potentially relative activities to supply more functional pathways and activities for metabolic network, and increasing the whole activities of microbial community, especially methanogenesis, to improve the strength and efficiency in anaerobic digestion process.

Self- and Air-Broadened Line Shapes in the 2v3 P and R Branches of 12CH4

NASA Technical Reports Server (NTRS)

Devi, V. Malathy; Benner, D. Chris; Sung, Keeyoon; Crawford, Timothy J.; Yu, Shanshan; Brown, Linda R.; Smith, Mary Ann H.; Mantz, Arlan W.; Boudon, Vincent; Ismail, Syed

2015-01-01

In this paper we report line shape parameters of 12CH4 for several hundred 2V(sub 3) transitions in the spectral regions 5891-5996 cm( exp -1) (P branch) and 6015-6115 cm(exp -1) (R branch). Air- and self-broadening coefficients were measured as a function of temperature; line mixing via off-diagonal relaxation matrix element coefficients was also obtained for 47 transition pairs. In total, nearly 1517 positions and intensities were retrieved, but many transitions were too weak for the line shape study. For this analysis, we used 25 high-resolution (0.0056 and 0.0067 cm(ex[ -1) and high signal-to-noise (S/N) spectra of high-purity 12CH4 and the same high-purity 12CH4 broadened by dry air recorded at different sample temperatures between 130 K and 295 K with the Bruker IFS 125HR Fourier transform spectrometer at JPL. Three different absorption cells were used (1) a White cell set to a path length of 13.09 m for room temperature data, (2) a single-pass 0.2038 m long coolable cell (for self-broadening) and (3) a multipass cell with 20.941 m total path coolable Herriott cell (for air-broadening). In total there were 13 spectra with pure 12CH4 (0.27-599 Torr) and 12 air-broadened spectra with total sample pressures of 80-805 Torr and volume mixing ratios (VMR) of methane between 0.18 and 1.0. An interactive multispectrum nonlinear least-squares technique was employed to fit the individual P10-P1 and R0-R10 manifolds in all the spectra simultaneously. Results obtained from the present analysis are compared to other recent measurements.

Seasonal thermoregulatory responses in mammals.

PubMed

Lovegrove, Barry G

2005-05-01

This study examined the proportional seasonal winter adjustments of total and mass-specific basal power (watts and watts g-1, respectively), thermal conductance (watts g-1 degrees C-1), non-shivering thermogenesis capacity (ratio of NST/basal power), body temperature ( degrees C), and body mass (g) of mammals. The responses are best summarized for three different body size classes; small mammals (<100 g), intermediate-sized mammals (0.1-10 kg), and large mammals (>10 kg). The principal adjustments of the small mammals center on energy conservation, especially the Dehnel Effect, the winter reduction in body size of as much as 50%, accompanied by reductions in mass-specific basal power. On average, these reductions reduce the total basal power approximately in direct proportion to the mass reductions. Reductions in mass-specific basal power are matched by concomitant reductions in conductance to maintain the setpoint body temperature during winter. The overall thermoregulatory adjustments in small mammals serve to (a) lower overall winter power consumption, (b) maintain the setpoint body temperature, and (c) lower the lower critical limit of thermoneutrality and hence thermoregulatory costs. In intermediate-size mammals, the seasonal response is centered more on increasing thermogenic capacity by increasing basal power and NST capacity, accompanied by predictable and large reductions in conductance. The Dehnel effect is negligible. Very large mammals undergo the largest reductions in total and mass-specific basal power and conductance. However, there are too few data to resolve whether the reductions in total basal power can be attributed to the Dehnel effect, because the moderate decreases in body mass may also be caused by nutritional stress. Apart from the seasonal changes in basal power, these observations are consistent with the predictions of Heldmaier's seasonal acclimatization model.

Observations and light curve solutions of a selection of middle-contact W UMa binaries

NASA Astrophysics Data System (ADS)

Kjurkchieva, Diana Petrova; Popov, Velimir Angelov; Lyubenova Vasileva, Doroteya; Petrov, Nikola Ivanov

2018-04-01

Photometric observations in Sloan g‧ and i‧ bands of W UMa binaries NSVS 4340949, T-Dra0–00959, GSC 03950–00707, NSVS 4665041, NSVS 4803568, MM Peg, MM Com and NSVS 4751449 are presented. The light curve solutions revealed that the components of each target are of G and K spectral types. The binaries of the sample have middle-contact configurations whose fillout factors are within the range 0.2–0.4. The only exception is NSVS 4751449 which is in deeper contact (fillout factor of 0.55). It precisely obeys the relation between mass ratio and fillout factor for deep, low mass ratio overcontact binaries. One of the eclipses of almost all targets (except MM Peg) is an occultation and their photometric mass ratios and solutions could be accepted with confidence. We found that the target components have almost equal temperatures but differ considerably in size and mass. The components of the partially-eclipsed MM Peg have close parameters. Our solutions reveal that NSVS 4340949, T-Dra0–00959, NSVS 4803568 and MM Com are of W subtype while GSC 03950–00707, NSVS 4665041, MM Peg and NSVS 4751449 are of A subtype. This subclassification is well-determined for all totally-eclipsed binaries. The targets confirm the trends in which W-subtype systems have smaller periods and lower temperatures than A subtype binaries.

Defect structure of high temperature hydride vapor phase epitaxy-grown epitaxial (0 0 0 1) AlN/sapphire using growth mode modification process

NASA Astrophysics Data System (ADS)

Su, Xujun; Zhang, Jicai; Huang, Jun; Zhang, Jinping; Wang, Jianfeng; Xu, Ke

2017-06-01

Defect structures were investigated by transmission electron microscopy for AlN/sapphire (0 0 0 1) epilayers grown by high temperature hydride vapor phase epitaxy using a growth mode modification process. The defect structures, including threading dislocations, inversion domains, and voids, were analyzed by diffraction contrast, high-resolution imaging, and convergent beam diffraction. AlN film growth was initiated at 1450 °C with high V/III ratio for 8 min. This was followed by low V/III ratio growth for 12 min. The near-interfacial region shows a high density of threading dislocations and inversion domains. Most of these dislocations have Burgers vector b = 1/3〈1 1 2 0〉 and were reduced with the formation of dislocation loops. In the middle range 400 nm < h < 2 μm, dislocations gradually aggregated and reduced to ∼109 cm-2. The inversion domains have a shuttle-like shape with staggered boundaries that deviate by ∼ ±5° from the c axis. Above 2 μm thickness, the film consists of isolated threading dislocations with a total density of 8 × 108 cm-2. Most of threading dislocations are either pure edge or mixed dislocations. The threading dislocation reduction in these films is associated with dislocation loops formation and dislocation aggregation-interaction during island growth with high V/III ratio.

Perspectives on dilution jet mixing. [in creating temperature patterns at combustor exits in gas turbine engines

NASA Technical Reports Server (NTRS)

Holdeman, J. D.; Srinivasan, R.

1986-01-01

A microcomputer code which displays 3-D oblique and 2-D plots of the temperature distribution downstream of jets mixing with a confined crossflow has been used to investigate the effects of varying the several independent flow and geometric parameters on the mixing. Temperature profiles calculated with this empirical model are presented to show the effects of orifice size and spacing, momentum flux ratio, density ratio, variable temperature mainstream, flow area convergence, orifice aspect ratio, and opposed and axially staged rows of jets.

Temperature dependence of giant magneto-resistance in PtMn- and Fe 2O 3-based specular spin valves

NASA Astrophysics Data System (ADS)

Kato, T.; Miyashita, K.; Iwata, S.; Tsunashima, S.; Sakakima, H.; Sugita, Y.; Kawawake, Y.

2002-02-01

Temperature dependence of the giant magneto-resistance (MR) was measured for spin valves with and without nano-oxide layer (NOL). In spin valves with NOL, the MR ratio increased more remarkably on lowering the temperature than in those without NOL. The temperature dependence of MR ratio and that of the resistivity were explained by using two-current model. The MR ratio enhanced with NOL is attributed to the increase of the mean free path of up-spin electrons.

Modulated-splitting-ratio fiber-optic temperature sensor

NASA Technical Reports Server (NTRS)

Beheim, Glenn; Anthan, Donald J.; Rys, John R.; Fritsch, Klaus; Ruppe, Walter A.

1988-01-01

A fiber-optic temperature sensor is described, which uses a small silicon beamsplitter whose splitting ratio varies as a function of temperature. A four-beam technique is used to measure the sensor's temperature-indicating splitting ratio. This referencing method provides a measurement that is largely independent of the transmission properties of the sensor's optical fiber link. A significant advantage of this sensor, relative to other fiber-optic sensors, is its high stability, which permits the fiber-optic components to be readily substituted, thereby simplifying the sensor's installation and maintenance.

The effect of 580 nm-based-LED mixed light on growth, adipose deposition, skeletal development, and body temperature of chickens.

PubMed

Yang, Yefeng; Zhen, Chenghuang; Yang, Bo; Yu, Yonghua; Pan, Jinming

2018-06-01

Though previous study indicated that the 580 nm-yellow-LED-light showed an stimulating effect on growth of chickens, the low luminous efficiency of the yellow LED light cannot reflect the advantage of energy saving. In present study, the cool white LED chips and yellow LED chips have been combined to fabricate the white × yellow mixed LED light, with an enhanced luminous efficiency. A total 300 newly hatched chickens were reared under various mixed LED light. The results indicated that the white × yellow mixed LED light had "double-edged sword" effects on bird's body weight, bone development, adipose deposition, and body temperature, depending on variations in ratios of yellow component. Low yellow ratio of mixed LED light (Low group) inhibited body weight, whereas medium and high yellow ratio of mixed LED light (Medium and High groups) promoted body weight, compared with white LED light (White group). A progressive change in yellow component gave rise to consistent changes in body weight over the entire experiment. Moreover, a positive relationship was observed between yellow component and feed conversion ratio. High group-treated birds had greater relative abdominal adipose weight than Medium group-treated birds (P = 0.048), whereas Medium group-treated birds had greater relative abdominal adipose weight than Low group-treated birds (P = 0.044). We found that mixed light improved body weight by enhancing skeletal development (R 2  = 0.5023, P = 0.0001) and adipose deposition (R 2  = 0.6012, P = 0.0001). Birds in the Medium, High and Yellow groups attained significantly higher surface temperatures compared with the White group (P = 0.010). The results suggest that the application of the mixed light with high level of yellow component can be used successfully to improve growth and productive performance in broilers. Copyright © 2018. Published by Elsevier B.V.

Impact of increasing temperature on snowfall in Switzerland

NASA Astrophysics Data System (ADS)

Serquet, G.; Marty, C.; Rebetez, M.

2012-04-01

The exact impact of changing temperatures on snow amounts is extremely important for mountainous regions, not only for hydrological aspects but also for winter tourism and the leisure industry in winter ski resorts. However, the impact of increasing temperatures on snowfall amounts is difficult to measure because of the large natural variability of precipitation. In addition, the impact of increasing temperatures varies, depending on region and altitude. Moreover, the impact of the observed increasing trend in temperature on snowfall and snow cover has usually been investigated on a seasonal basis only. On a monthly basis, the relationship between this increase in temperature and snowfall is still largely unknown. Of particular concern are the autumn and spring months and variations with altitude. In order to isolate the impact of changing temperatures on snowfall from the impact of changes in the frequency and intensity of total precipitation, we analyzed the proportion of snowfall days compared to precipitation days for each month from November to April in Switzerland. Our analyses concern 52 meteorological stations located between 200 and 2700 m asl over a 48 year time span. Our results show clear decreasing trends in snowfall days relative to precipitation days for all months (November to April) during the study period 1961-2008. Moreover, the present conditions in December, January and February correspond to those measured in the 1960's in November and March. During the whole snow season, the snowfall ratios have been transferred in elevation by at least 300 m from 1961 to 2008. This means that with an expected temperature increase during the coming decades at least similar to the temperature rise of recent decades, we can assume an additional similar altitudinal transfer of the snowfall days relative to precipitation days ratios. The current situation in November and March could thus become the future situation in December, January and February. During the coming decades, the December, January and February snowfall days relative to precipitation days ratios for the altitude class 1101-1400 m asl would gradually shrink to only approximately 50%. For ski resorts with a base below 1400 m asl, December, January and February will be problematic, because at least one out of two precipitation days will consist of rainfall only. The beginning and end of the ski seasons (November, March-April) will also be affected by the transfer in altitude of snowfall, as currently already approximately every second precipitation day consists of rain up to 1400 m asl in November and March and up to 1700 m asl in April.

Mg/Ca ratios of the benthic foraminifera Oridorsalis umbonatus obtained by laser ablation from core top sediments: Relationship to bottom water temperature

NASA Astrophysics Data System (ADS)

Rathmann, SöHnke; Hess, Silvia; Kuhnert, Henning; Mulitza, Stefan

2004-12-01

A laser ablation system connected to an inductively coupled plasma mass spectrometer was used to determine Mg/Ca ratios of the benthic foraminifera Oridorsalis umbonatus. A set of modern core top samples collected along a depth transect on the continental slope off Namibia (320-2300 m water depth; 2.9° to 10.4°C) was used to calibrate the Mg/Ca ratio against bottom water temperature. The resulting Mg/Ca-bottom water temperature relationship of O. umbonatus is described by the exponential equation Mg/Ca = 1.528*e0.09*BWT. The temperature sensitivity of this equation is similar to previously published calibrations based on Cibicidoides species, suggesting that the Mg/Ca ratio of O. umbonatus is a valuable proxy for thermocline and deep water temperature.

Gasification of empty fruit bunch with carbon dioxide in an entrained flow gasifier for syngas production

NASA Astrophysics Data System (ADS)

Rahmat, N. F. H.; Rasid, R. A.

2017-06-01

The main objectives of this work are to study the gasification of EFB in an atmospheric entrained flow gasifier, using carbon dioxide (CO2) as its gasifying agent and to determine the optimum gasification operating conditions, which includes temperature and the oxidant to fuel (OTF) ratio. These were evaluated in terms of important gasification parameters such as the concentration of hydrogen (H2) and carbon monoxide (CO) produced the syngas ratio H2/CO and carbon conversion. The gasification reactions take place in the presence of CO2 at very high reaction rate because of the high operating temperature (700°C - 900°C). The use of CO2 as the oxidant for gasification process can improve the composition of syngas produced as in the Boudouard reaction. Rise of reaction temperature which is 900°C will increase the concentration of both H2 & CO by up to 81 and 30 respectively, though their production were decreased after the OTF ratio of 0.6 for temperature 700°C & 800°C and OTF ratio 0.8 for temperature 750°C. The operating temperature must be higher than 850°C to ensure the Boudouard reaction become the more prominent reaction for the biomass gasification. The syngas ratio obtained was in the range of ≈ 0.6 - 2.4 which is sufficient for liquid fuel synthesis. For the carbon conversion, the highest fuel conversion recorded at temperature 850°C for all OTF ratios. As the OTF ratio increases, it was found that there was an increase in the formation of CO and H2. This suggests that to achieve higher carbon conversion, high operating temperature and OTF ratio are preferable. This study provides information on the optimum operating conditions for the gasification of biomass, especially the EFB, hence may upsurge the utilization of biomass waste as an energy source.

Thermodynamic equilibrium calculations of hydrogen production from the combined processes of dimethyl ether steam reforming and partial oxidation

NASA Astrophysics Data System (ADS)

Semelsberger, Troy A.; Borup, Rodney L.

Thermodynamic analyses of producing a hydrogen-rich fuel-cell feed from the combined processes of dimethyl ether (DME) partial oxidation and steam reforming were investigated as a function of oxygen-to-carbon ratio (0.00-2.80), steam-to-carbon ratio (0.00-4.00), temperature (100 °C-600 °C), pressure (1-5 atm) and product species. Thermodynamically, dimethyl ether processed with air and steam generates hydrogen-rich fuel-cell feeds; however, the hydrogen concentration is less than that for pure DME steam reforming. Results of the thermodynamic processing of dimethyl ether indicate the complete conversion of dimethyl ether to hydrogen, carbon monoxide and carbon dioxide for temperatures greater than 200 °C, oxygen-to-carbon ratios greater than 0.00 and steam-to-carbon ratios greater than 1.25 at atmospheric pressure (P = 1 atm). Increasing the operating pressure has negligible effects on the hydrogen content. Thermodynamically, dimethyl ether can produce concentrations of hydrogen and carbon monoxide of 52% and 2.2%, respectively, at a temperature of 300 °C, and oxygen-to-carbon ratio of 0.40, a pressure of 1 atm and a steam-to-carbon ratio of 1.50. The order of thermodynamically stable products (excluding H 2, CO, CO 2, DME, NH 3 and H 2O) in decreasing mole fraction is methane, ethane, isopropyl alcohol, acetone, n-propanol, ethylene, ethanol and methyl-ethyl ether; trace amounts of formaldehyde, formic acid and methanol are observed. Ammonia and hydrogen cyanide are also thermodynamically favored products. Ammonia is favored at low temperatures in the range of oxygen-to-carbon ratios of 0.40-2.50 regardless of the steam-to-carbon ratio employed. The maximum ammonia content (i.e., 40%) occurs at an oxygen-to-carbon ratio of 0.40, a steam-to-carbon ratio of 1.00 and a temperature of 100 °C. Hydrogen cyanide is favored at high temperatures and low oxygen-to-carbon ratios with a maximum of 3.18% occurring at an oxygen-to-carbon ratio of 0.40 and a steam-to-carbon ratio of 0.00 in the temperature range of 400 °C-500 °C. Increasing the system pressure shifts the equilibrium toward ammonia and hydrogen cyanide.

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

Leung, Bonnie; Hitchcock, Adam; Brash, John

Spun-cast films of polystyrene (PS) blended with polylactide (PLA) were visualized and characterized using atomic force microscopy (AFM) and synchrotron-based X-ray photoemission electron microscopy (X-PEEM). The composition of the two polymers in these systems was determined by quantitative chemical analysis of near-edge X-ray absorption signals recorded with X-PEEM. The surface morphology depends on the ratio of the two components, the total polymer concentration, and the temperature of vacuum annealing. For most of the blends examined, PS is the continuous phase with PLA existing in discrete domains or segregated to the air?polymer interface. Phase segregation was improved with further annealing. Amore » phase inversion occurred when films of a 40:60 PS:PLA blend (0.7 wt percent loading) were annealed above the glass transition temperature (Tg) of PLA.« less

Organic Carbon Transformation and Mercury Methylation in Tundra Soils from Barrow Alaska

DOE Data Explorer

Liang, L.; Wullschleger, Stan; Graham, David; Gu, B.; Yang, Ziming

2016-04-20

This dataset includes information on soil labile organic carbon transformation and mercury methylation for tundra soils from Barrow, Alaska. The soil cores were collected from high-centered polygon (trough) at BEO and were incubated under anaerobic laboratory conditions at both freezing and warming temperatures for up to 8 months. Soil organic carbon including reducing sugars, alcohols, and organic acids were analyzed, and CH4 and CO2 emissions were quantified. Net production of methylmercury and Fe(II)/Fe(total) ratio were also measured and provided in this dataset.

Static and wind tunnel near-field/far-field jet noise measurements from model scale single-flow baseline and suppressor nozzles. Volume 1: Noise source locations and extrapolation of static free-field jet noise data

NASA Technical Reports Server (NTRS)

Jaeck, C. L.

1976-01-01

A test was conducted in the Boeing Large Anechoic Chamber to determine static jet noise source locations of six baseline and suppressor nozzle models, and establish a technique for extrapolating near field data into the far field. The test covered nozzle pressure ratios from 1.44 to 2.25 and jet velocities from 412 to 594 m/s at a total temperature of 844 K.

Effect of Oxygen addition on altitude blowout and relight of an experimental combustor segment

NASA Technical Reports Server (NTRS)

Norgren, C. T.; Ingebo, R. D.

1974-01-01

The effect of oxygen addition on the low pressure altitude blowout limits of an experimental combustor segment was investigated. Data were obtained for two inlet-air temperatures, two inlet-airflow rates, and a constant fuel-air ratio of 0.020 with Jet A fuel. It was shown that the pressure at blowout could be reduced to correspond to an increase in altitude of 4.6 kilometers with oxygen flow rates of 8 to 16 percent by weight of the total fuel flow.

Heating mechanism(s) for transition layers in giants

NASA Technical Reports Server (NTRS)

Bohm-Vitense, Erika; Mena-Werth, Jose

1991-01-01

The emission-line fluxes of lines originating in the lower parts of the transition layers between stellar chromospheres and coronas are studied. Simon and Drake (1989) suspect different heating mechanisms for 'hot' and cool stars. Changes in the flux ratios for the C IV to C II emission lines support this suspicion. Large C IV/C II line flux ratios appear to be indicative of magnetically controlled heating. A correlation between excess continuum flux around 1950 A and C II emission-line fluxes are confirmed for the cooler giants (late F and cooler). Excess continuum flux correlates positively with large C IV/C II line flux ratio. The excess continuum flux corresponds to an increase in temperature by several hundred degrees in layers with a mean optical depth of about 0.03. For chromospherically active stars these layers experience a mechanical flux deposition of the order of 1 percent of the total radiative flux. This flux is tentatively identified as an MHD wave flux similar to Alfven waves.

Idle efficiency and pollution results for two-row swirl-can combustors having 72 modules

NASA Technical Reports Server (NTRS)

Biaglow, J. A.; Trout, A. M.

1975-01-01

Two 72-swirl-can-module combustors were investigated in a full annular combustor test facility at engine idle conditions typical of a 30:1 pressure-ratio engine. The effects of radial and circumferential fuel scheduling on combustion efficiency and gaseous pollutants levels were determined. Test conditions were inlet-air temperature, 452 K; inlet total pressure, 34.45 newtons per square centimeter; and reference velocity, 19.5 meters per second. A maximum combustion efficiency of 98.1 percent was achieved by radial scheduling of fuel to the inner row of swirl-can modules. Emission index values were 6.9 for unburned hydrocarbons and 50.6 for carbon monoxide at a fuel-air ratio of 0.0119. Circumferential fuel scheduling of two 90 degree sectors of the swirl-can arrays produced a maximum combustion efficiency of 97.3 percent. The emission index values were 12.0 for unburned hydrocarbons and 69.2 for carbon monoxide at a fuel-air ratio of 0.0130.

A Congeneric Comparison Shows That Experimental Warming Enhances the Growth of Invasive Eupatorium adenophorum

PubMed Central

He, Wei-Ming; Li, Jing-Ji; Peng, Pei-Hao

2012-01-01

Rising air temperatures may change the risks of invasive plants; however, little is known about how different warming timings affect the growth and stress-tolerance of invasive plants. We conducted an experiment with an invasive plant Eupatorium adenophorum and a native congener Eupatorium chinense, and contrasted their mortality, plant height, total biomass, and biomass allocation in ambient, day-, night-, and daily-warming treatments. The mortality of plants was significantly higher in E. chinense than E. adenophorum in four temperature regimes. Eupatorium adenophorum grew larger than E. chinense in the ambient climate, and this difference was amplified with warming. On the basis of the net effects of warming, daily-warming exhibited the strongest influence on E. adenophorum, followed by day-warming and night-warming. There was a positive correlation between total biomass and root weight ratio in E. adenophorum, but not in E. chinense. These findings suggest that climate warming may enhance E. adenophorum invasions through increasing its growth and stress-tolerance, and that day-, night- and daily-warming may play different roles in this facilitation. PMID:22536425

Winds and temperatures of the Arctic middle atmosphere during January measured by Doppler lidar

NASA Astrophysics Data System (ADS)

Hildebrand, Jens; Baumgarten, Gerd; Fiedler, Jens; Lübken, Franz-Josef

2017-11-01

We present an extensive data set of simultaneous temperature and wind measurements in the Arctic middle atmosphere. It consists of more than 300 h of Doppler Rayleigh lidar observations obtained during three January seasons (2012, 2014, and 2015) and covers the altitude range from 30 km up to about 85 km. The data set reveals large year-to-year variations in monthly mean temperatures and winds, which in 2012 are affected by a sudden stratospheric warming. The temporal evolution of winds and temperatures after that warming are studied over a period of 2 weeks, showing an elevated stratopause and the reformation of the polar vortex. The monthly mean temperatures and winds are compared to data extracted from the Integrated Forecast System of the European Centre for Medium-Range Weather Forecasts (ECMWF) and the Horizontal Wind Model (HWM07). Lidar and ECMWF data show good agreement of mean zonal and meridional winds below ≈ 55 km altitude, but we also find mean temperature, zonal wind, and meridional wind differences of up to 20 K, 20 m s-1, and 5 m s-1, respectively. Differences between lidar observations and HWM07 data are up to 30 m s-1. From the fluctuations of temperatures and winds within single nights we extract the potential and kinetic gravity wave energy density (GWED) per unit mass. It shows that the kinetic GWED is typically 5 to 10 times larger than the potential GWED, the total GWED increases with altitude with a scale height of ≈ 16 km. Since temporal fluctuations of winds and temperatures are underestimated in ECMWF, the total GWED is underestimated as well by a factor of 3-10 above 50 km altitude. Similarly, we estimate the energy density per unit mass for large-scale waves (LWED) from the fluctuations of nightly mean temperatures and winds. The total LWED is roughly constant with altitude. The ratio of kinetic to potential LWED varies with altitude over 2 orders of magnitude. LWEDs from ECMWF data show results similar to the lidar data. From the comparison of GWED and LWED, it follows that large-scale waves carry about 2 to 5 times more energy than gravity waves.

Effects of Temperature and Carbon-Nitrogen (C/N) Ratio on the Performance of Anaerobic Co-Digestion of Dairy Manure, Chicken Manure and Rice Straw: Focusing on Ammonia Inhibition

PubMed Central

Wang, Xiaojiao; Lu, Xingang; Li, Fang; Yang, Gaihe

2014-01-01

Anaerobic digestion is a promising alternative to disposal organic waste and co-digestion of mixed organic wastes has recently attracted more interest. This study investigated the effects of temperature and carbon-nitrogen (C/N) ratio on the performance of anaerobic co-digestion of dairy manure (DM), chicken manure (CM) and rice straw (RS). We found that increased temperature improved the methane potential, but the rate was reduced from mesophilic (30∼40°C) to thermophilic conditions (50∼60°C), due to the accumulation of ammonium nitrogen and free ammonia and the occurrence of ammonia inhibition. Significant ammonia inhibition was observed with a C/N ratio of 15 at 35°C and at a C/N ratio of 20 at 55°C. The increase of C/N ratios reduced the negative effects of ammonia and maximum methane potentials were achieved with C/N ratios of 25 and 30 at 35°C and 55°C, respectively. When temperature increased, an increase was required in the feed C/N ratio, in order to reduce the risk of ammonia inhibition. Our results revealed an interactive effect between temperature and C/N on digestion performance. PMID:24817003

Effects of dietary DL-2-hydroxy-4(methylthio)butanoic acid supplementation on growth performance, indices of ascites syndrome, and antioxidant capacity of broilers reared at low ambient temperature.

PubMed

Yang, G L; Zhang, K Y; Ding, X M; Zheng, P; Luo, Y H; Bai, S P; Wang, J P; Xuan, Y; Su, Z W; Zeng, Q F

2016-08-01

This study examined the effects of dietary DL-2-hydroxy-4(methylthio)butanoic acid (DL-HMTBA) supplementation on growth performance, antioxidant capacity, and ascites syndrome (AS) in broilers reared at low ambient temperature (LAT) from 7 to 28 days of age. Eight hundred 7-day-old broilers were randomly assigned to two ambient temperatures (LAT and normal ambient temperature [NAT]), four supplemental DL-HMTBA levels (0.17, 0.34, 0.51, and 0.68 %) of the basal diet in a 2 × 4 factorial arrangement (ten replicate pens; ten birds/pen). LAT and NAT indicate temperatures of 12-14 and 24-26 °C in two chambers, respectively, and broilers were reared at these temperatures from 7 to 28 days of age. LAT significantly decreased body weight gain (P < 0.001), serum glutathione (GSH) content (day 14, P = 0.02; day 28, P = 0.045), glutathione peroxidase (GSH-Px) activity, and total antioxidant capacity (T-AOC) at 21 days (P = 0.001, 0.015) and 28 days (P = 0.017, 0.010) and increased feed conversion ratio (FCR) (P < 0.001), serum malondialdehyde (day 21, P = 0.000) and protein carbonyl Level (day 14, P = 0.003; day 21, P = 0.035). As for incidence of AS, there were significant effects of LAT on red blood cell (RBC) count (P < 0.05), hematocrit (HCT) (P < 0.05), and the right to total ventricular weight ratio (RV/TV) at 21 days (P = 0.012) and 28 days (P = 0.046). Supplementation of DL-HMTBA markedly decreased RV/TV at day 28 (P = 0.021), RBC (day 21, P = 0.008), HCT (day 21, P < 0.001), mean cell hemoglobin (day 14, P = 0.035; day 21, P = 0.003), and serum protein carbonyl level (day 21, P = 0.009), while significantly increased serum GSH content (day 14, P = 0.022; day 28, P = 0.001), SOD and GSH-Px activities at 21 days of age (P < 0.001 and P = 0.037). The optimal supplemental DL-HMTBA levels in basal diet of broilers aged from 7 to 28 days under low or normal temperatures were similar, so the authors recommended supplemental of DL-HMTBA level was 0.46 %.

Electronic waste disassembly with industrial waste heat.

PubMed

Chen, Mengjun; Wang, Jianbo; Chen, Haiyian; Ogunseitan, Oladele A; Zhang, Mingxin; Zang, Hongbin; Hu, Jiukun

2013-01-01

Waste printed circuit boards (WPCBs) are resource-rich but hazardous, demanding innovative strategies for post-consumer collection, recycling, and mining for economically precious constituents. A novel technology for disassembling electronic components from WPCBs is proposed, using hot air to melt solders and to separate the components and base boards. An automatic heated-air disassembling equipment was designed to operate at a heating source temperature at a maximum of 260 °C and an inlet pressure of 0.5 MPa. A total of 13 individual WPCBs were subjected to disassembling tests at different preheat temperatures in increments of 20 °C between 80 and 160 °C, heating source temperatures ranging from 220 to 300 °C in increments of 20 °C, and incubation periods of 1, 2, 4, 6, or 8 min. For each experimental treatment, the disassembly efficiency was calculated as the ratio of electronic components released from the board to the total number of its original components. The optimal preheat temperature, heating source temperature, and incubation period to disassemble intact components were 120 °C, 260 °C, and 2 min, respectively. The disassembly rate of small surface mount components (side length ≤ 3 mm) was 40-50% lower than that of other surface mount components and pin through hole components. On the basis of these results, a reproducible and sustainable industrial ecological protocol using steam produced by industrial exhaust heat coupled to electronic-waste recycling is proposed, providing an efficient, promising, and green method for both electronic component recovery and industrial exhaust heat reutilization.

Optimizing extraction conditions of crude fiber, phenolic compounds, flavonoids and antioxidant activity of date seed powder.

PubMed

Afifi, Hanan S; Hashim, Isameldin B; Altubji, Sabreen I

2017-12-01

The objective of this study was to optimize the extraction conditions of crude fiber, phenolic compounds, flavonoids, and antioxidant activity from date seeds powder, using Response Surface Methodology. A central composite design with four independent variables; concentration of ethanol (X 1  = 25, 50 and 75% v/v), solvent: sample ratio (X 2  = 40:1, 50:1 and 60:1 v/w), temperature (X 3  = 45, 55 and 65 °C), and extraction time (X 4  = 1, 2 and 3 h) and a three level face centered cube design were used. A total of twenty nine experimental runs with five replicates at the central point were used to study the response variables using two extraction cycles. Maximum phenolic compound content (71.6 mg GAE/100 g) was extracted using 50% ethanol solution with 40:1 solvent: sample ratio for 1 h at 55 °C. While the maximum antioxidant activity (55.02 µmol Fe(II)/g) was obtained using similar ethanol concentration and solvent: sample ratio except at lower temperature (45 °C) for 2 h. On other hand, the maximum flavonoids content (455.77 mg CEQ/100 g) was reached by using 50% concentration, 50:1 solvent: sample ratio at 65 °C for 3 h. In contrast, the content of fiber was not affected by the different extraction conditions. Results indicate that using combination of extracted conditions, have a great potential for extracting all depending compounds except crude fiber.

High performance perpendicular magnetic tunnel junction with Co/Ir interfacial anisotropy for embedded and standalone STT-MRAM applications

NASA Astrophysics Data System (ADS)

Huai, Yiming; Gan, Huadong; Wang, Zihui; Xu, Pengfa; Hao, Xiaojie; Yen, Bing K.; Malmhall, Roger; Pakala, Nirav; Wang, Cory; Zhang, Jing; Zhou, Yuchen; Jung, Dongha; Satoh, Kimihiro; Wang, Rongjun; Xue, Lin; Pakala, Mahendra

2018-02-01

High volume spin transfer torque magnetoresistance random access memory (STT-MRAM) for standalone and embedded applications requires a thin perpendicular magnetic tunnel junction (pMTJ) stack (˜10 nm) with a tunnel magnetoresistance (TMR) ratio over 200% after high temperature back-end-of-line (BEOL) processing up to 400 °C. A thin reference layer with low magnetic moment and strong perpendicular magnetic anisotropy (PMA) is key to reduce the total thickness of the full pMTJ stack. We demonstrated strong interfacial PMA and a perpendicular Ruderman-Kittel-Kasuya-Yosida exchange interaction in the Co/Ir system. Owing to the additional high PMA at the Ir/Co interface in combination with a conventional CoFeB/MgO interface in the Ir/Co/Mo/CoFeB/MgO reference layer, the full film pMTJ showed a TMR ratio over 210% after annealing at 400 °C for 150 min. The high TMR ratio can be attributed to the thin stack design by combining a thin reference layer with the efficient compensation by a thin pinned layer. The annealing stability may be explained by the absence of solid solution in the Co-Ir system and the low oxygen affinity of Mo in the reference layer and the free layer. High device performance with a TMR ratio over 210% was also confirmed after subjecting the patterned devices to BEOL processing temperatures of up to 400 °C. This proposed pMTJ design is suitable for both standalone and embedded STT-MRAM applications.

Measurements of Aerodynamic Heat Transfer and Boundary-Layer Transition on a 15 deg. Cone in Free Flight at Supersonic Mach Numbers up to 5.2

NASA Technical Reports Server (NTRS)

Rumsey, Charles B.; Lee, Dorothy B.

1961-01-01

Measurements of aerodynamic heat transfer have been made at several stations on the 15 deg total-angle conical nose of a rocket-propelled model in free flight at Mach numbers up to 5.2. Data are presented for a range of local Mach number just outside the boundary layer from 1.40 to 4.65 and a range of local Reynolds number from 3.8 x 10(exp 6) to 46.5 x 10(exp 6), based on length from the nose tip to a measurement station. Laminar, transitional, and turbulent heat-transfer coefficients were measured. The laminar data were in agreement with laminar theory for cones, and the turbulent data agreed well with turbulent theory for cones using Reynolds number based on length from the nose tip. At a nearly constant ratio of wall to local static temperature of 1.2 the Reynolds number of transition increased from 14 x 10(exp 6) to 30 x 10(exp 6) as Mach number increased from 1.4 to 2.9 and then decreased to 17 x 10(exp 6) as Mach number increased to 3.7. At Mach numbers near 3.5, transition Reynolds numbers appeared to be independent of skin temperature at skin temperatures very cold with respect to adiabatic wall temperature. The transition Reynolds number was 17.7 x 10(exp 6) at a condition of Mach number and ratio of wall to local static temperature near that for which three-dimensional disturbance theory has been evaluated and has predicted laminar boundary-layer stability to very high Reynolds numbers (approximately 10(exp 12)).

Evaluation of Turbulence-Model Performance in Jet Flows

NASA Technical Reports Server (NTRS)

Woodruff, S. L.; Seiner, J. M.; Hussaini, M. Y.; Erlebacher, G.

2001-01-01

The importance of reducing jet noise in both commercial and military aircraft applications has made jet acoustics a significant area of research. A technique for jet noise prediction commonly employed in practice is the MGB approach, based on the Lighthill acoustic analogy. This technique requires as aerodynamic input mean flow quantities and turbulence quantities like the kinetic energy and the dissipation. The purpose of the present paper is to assess existing capabilities for predicting these aerodynamic inputs. Two modern Navier-Stokes flow solvers, coupled with several modern turbulence models, are evaluated by comparison with experiment for their ability to predict mean flow properties in a supersonic jet plume. Potential weaknesses are identified for further investigation. Another comparison with similar intent is discussed by Barber et al. The ultimate goal of this research is to develop a reliable flow solver applicable to the low-noise, propulsion-efficient, nozzle exhaust systems being developed in NASA focused programs. These programs address a broad range of complex nozzle geometries operating in high temperature, compressible, flows. Seiner et al. previously discussed the jet configuration examined here. This convergent-divergent nozzle with an exit diameter of 3.6 inches was designed for an exhaust Mach number of 2.0 and a total temperature of 1680 F. The acoustic and aerodynamic data reported by Seiner et al. covered a range of jet total temperatures from 104 F to 2200 F at the fully-expanded nozzle pressure ratio. The aerodynamic data included centerline mean velocity and total temperature profiles. Computations were performed independently with two computational fluid dynamics (CFD) codes, ISAAC and PAB3D. Turbulence models employed include the k-epsilon model, the Gatski-Speziale algebraic-stress model and the Girimaji model, with and without the Sarkar compressibility correction. Centerline values of mean velocity and mean temperature are compared with experimental data.

Microwave blanching and drying characteristics of Centella asiatica (L.) urban leaves using tray and heat pump-assisted dehumidified drying.

PubMed

Trirattanapikul, W; Phoungchandang, S

2014-12-01

The appropriate stage of maturity of Centella asiatica (L.) Urban leaves was investigated. Mature leaves with large diameter contained high total phenolics and % inhibition. Microwave blanching for 30 s retained the highest total phenolics and the microwave blanching for 30 s and 45 s retained the highest % inhibition. Modified Henderson and Modified Chung-Pfost models showed the best fit to both fresh and blanched leaves for equilibrium moisture content, Xe = f(RHe, T) and equilibrium relative humidity, RHe = f(Xe, T), respectively. The Modified Page model was the most effective model in describing the leaf drying. All drying was in the falling rate period. The drying constant was related to drying air temperature using the Arrhenius model. Effective moisture diffusivities increased with increasing temperature and blanching treatments as well as dehumidification by heat pump-assisted dehumidified dryer. The heat pump-assited dehumidified drying incorporated by the microwave blanching could reduce the drying time at 40 °C by 31.2 % and increase % inhibition by 6.1 %. Quality evaluation by total phenolics, % inhibition and rehydration ratio showed the best quality for C. asiatica leaves pretreated by microwave blanching and dried at 40 °C in heat pump-assisted dehumidified dryer.

Effects of Low Temperature and Freeze-Thaw Cycles on Hydrocarbon Biodegradation in Arctic Tundra Soil

PubMed Central

Eriksson, Mikael; Ka, Jong-Ok; Mohn, William W.

2001-01-01

Degradation of petroleum hydrocarbons was monitored in microcosms with diesel fuel-contaminated Arctic tundra soil incubated for 48 days at low temperatures (−5, 0, and 7°C). An additional treatment was incubation for alternating 24-h periods at 7 and −5°C. Hydrocarbons were biodegraded at or above 0°C, and freeze-thaw cycles may have actually stimulated hydrocarbon biodegradation. Total petroleum hydrocarbon (TPH) removal over 48 days in the 7, 0, and 7 and −5°C treatments, respectively, was 450, 300, and 600 μg/g of soil. No TPH removal was observed at −5°C. Total carbon dioxide production suggested that TPH removal was due to biological mineralization. Bacterial metabolic activity, indicated by RNA/DNA ratios, was higher in the middle of the experiment (day 21) than at the start, in agreement with measured hydrocarbon removal and carbon dioxide production activities. The total numbers of culturable heterotrophs and of hydrocarbon degraders did not change significantly over the 48 days of incubation in any of the treatments. At the end of the experiment, bacterial community structure, evaluated by ribosomal intergenic spacer length analysis, was very similar in all of the treatments but the alternating 7 and −5°C treatment. PMID:11679333

Anaerobic co-digestion of kitchen waste and pig manure with different mixing ratios.

PubMed

Tian, Hailin; Duan, Na; Lin, Cong; Li, Xue; Zhong, Mingzhu

2015-07-01

Anaerobic co-digestion of kitchen waste (KW) and pig manure (PM) with seven different PM to KW total solids (TS) ratios of 1:0, 5:1, 3:1, 1:1, 1:3, 1:5 and 0:1 was conducted at mesophilic temperature (35 ± 1 °C) to investigate the feasibility and process performance. The co-digestion of PM and KW was found to be an available way to enhance methane production compared with solo-digestion of PM or KW. The ratio of PM to KW of 1:1 got the highest biodegradability (BDA) of 85.03% and a methane yield of 409.5 mL/gVS. For the co-digestion of KW and PM, there was no obvious inhibition of ammonia nitrogen because it was in an acceptable range from 1380 mg/L to 2020 mg/L in the whole process. However, severe methane inhibition and long lag phase due to the accumulation of volatile fatty acids (VFAs) was observed while the KW content was over 50%, and in the lag phase, propionic acid and butyric acid made up the major constituents of the total VFAs. The technical digestion time (T80: the time it takes to produce 80% of the digester's maximum gas production) of the above 7 ratios was 15, 21, 22, 27, 49, 62 and 61 days, respectively. In this study, a mixing ratio of 1:1 for PM and KW was found to maximize BDA and methane yield, provided a short digestion time and stable digestion performance and was therefore recommended for further study and engineering application. Copyright © 2014 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

Composting of pig manure and forest green waste amended with industrial sludge.

PubMed

Arias, O; Viña, S; Uzal, M; Soto, M

2017-05-15

The aim of this research was to study the composting of chestnut forest green waste (FGW) from short rotation chestnut stands amended with sludge resulting from the manufacture of Medium Density Fibreboard (MDFS) and pig manure (PM). Both FGW and MDFS presented low biodegradation potential but different characteristics in granulometry and bulk density that make its mixture of interest to achieve high composting temperatures. PM decreased the C/N ratio of the mixture and increased its moisture content (MC). Three mixtures of MDFS:FGW at volume ratios of 1:1.3 (M2), 1:2.4 (M3) and 0:1 (M4) were composted after increasing its MC to about 70% with PM. A control with food waste (OFW) and FGW (1:2.4 in volume) (M1) was run in parallel. Watering ratios reached 0.25 (M1), 1.08 (M2) 1.56 (M3) and 4.35 (M4) L PM/kg TS of added solids wastes. Treatments M2 and M3 reached a thermophilic phase shorter than M1, whilst M4 remained in the mesophilic range. After 48days of composting, temperature gradients in respect to ambient temperature were reduced, but the mineralization process continued for around 8months. Final reduction in total organic carbon reached 35-56%, depending mainly on the content in MDFS. MDFS addition to composting matrices largely reduced nitrogen losses, which range from 22% (M2) to 37% (M3) and 53% (M4). Final products had high nutrient content, low electrical conductivity and low heavy metal content which make it a valuable product for soil fertilization, right to amend in the chestnut forests and as a pillar of their sustainable management. Copyright © 2017 Elsevier B.V. All rights reserved.

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

Aggarwal, J.K.; Palmer, M.R.

Boron isotope ratios have been determined in a variety of different geothermal waters from hydrothermal systems across Iceland. Isotope ratios from the high temperature meteoric water recharged systems reflect the isotope ratio of the host rocks without any apparent fractionation. Seawater recharged geothermal systems exhibit more positive {delta}{sup 11}B values than the meteoric water recharged geothermal systems. Water/rock ratios can be assessed from boron isotope ratios in the saline hydrothermal systems. Low temperature hydrothermal systems also exhibit more positive {delta}{sup 11}B than the high temperature systems, indicating fractionation of boron due to adsorption of the lighter isotope onto secondary minerals.more » Fractionation of boron in carbonate deposits may indicate the level of equilibrium attained within the systems.« less

An experimental study of the autoignition characteristics of conventional jet fuel/oxidizer mixtures: Jet-A and JP-8

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

Kumar, Kamal; Sung, Chih-Jen

2010-04-15

Ignition delay times of Jet-A/oxidizer and JP-8/oxidizer mixtures are measured using a heated rapid compression machine at compressed charge pressures corresponding to 7, 15, and 30 bar, compressed temperatures ranging from 650 to 1100 K, and equivalence ratios varying from 0.42 to 2.26. When using air as the oxidant, two oxidizer-to-fuel mass ratios of 13 and 19 are investigated. To achieve higher compressed temperatures for fuel lean mixtures (equivalence ratio of {proportional_to}0.42), argon dilution is also used and the corresponding oxidizer-to-fuel mass ratio is 84.9. For the conditions studied, experimental results show two-stage ignition characteristics for both Jet-A and JP-8.more » Variations of both the first-stage and overall ignition delays with compressed temperature, compressed pressure, and equivalence ratio are reported and correlated. It is noted that the negative temperature coefficient phenomenon becomes more prominent at relatively lower pressures. Furthermore, the first-stage-ignition delay is found to be less sensitive to changes in equivalence ratio and primarily dependent on temperature. (author)« less

Sex ratio estimations of loggerhead sea turtle hatchlings by histological examination and nest temperatures at Fethiye beach, Turkey

NASA Astrophysics Data System (ADS)

Kaska, Yakup; Ilgaz, Çetin; Özdemir, Adem; Başkale, Eyüp; Türkozan, Oğuz; Baran, Ibrahim; Stachowitsch, Michael

2006-07-01

Hatchling sex ratios in the loggerhead turtle ( Caretta caretta) were estimated by placing electronic temperature recorders in 21 nests at Fethiye beach during 2000 2002. Over the seasons, the mean temperature in the middle third of the incubation period ranged from 26.7 to 32.1°C, and incubation periods ranged from 49 to 67 days. Based on the mean temperatures during the middle third of the incubation period, and on histologically sexed dead hatchlings, the sex ratios of hatchlings at Fethiye beach were roughly equal, i.e. 60 65% of the hatchlings were females. This contrasts with the highly female-skewed sex ratios in loggerhead turtles elsewhere; Fethiye has a relatively high proportion of male hatchlings. For endangered sea turtles, the knowledge of hatchling sex ratios at different beaches, coupled with appropriate conservation measures, can make an important contribution to their survival.

Seasonal shifts in sex ratios are mediated by maternal effects and fluctuating incubation temperatures.

PubMed

Carter, Amanda W; Bowden, Rachel M; Paitz, Ryan T

2017-04-01

Sex-specific maternal effects can be adaptive sources of phenotypic plasticity. Reptiles with temperature-dependent sex determination (TSD) are a powerful system to investigate such maternal effects because offspring phenotype, including sex, can be sensitive to maternal influences such as oestrogens and incubation temperatures.In red-eared slider turtles ( Trachemys scripta ), concentrations of maternally derived oestrogens and incubation temperatures increase across the nesting season; we wanted to determine if sex ratios shift in a seasonally concordant manner, creating the potential for sex-specific maternal effects, and to define the sex ratio reaction norms under fluctuating temperatures across the nesting season.Eggs from early and late season clutches were incubated under a range of thermally fluctuating temperatures, maternally derived oestradiol concentrations were quantified via radioimmunoassay, and hatchling sex was identified. We found that late season eggs had higher maternal oestrogen concentrations and were more likely to produce female hatchlings. The sex ratio reaction norm curves systematically varied with season, such that with even a slight increase in temperature (0.5°C), late season eggs produced up to 49% more females than early season eggs.We found a seasonal shift in sex ratios which creates the potential for sex-specific phenotypic matches across the nesting season driven by maternal effects. We also describe, for the first time, systematic variation in the sex ratio reaction norm curve within a single population in a species with TSD.

Effect of addition of nanoparticle TiO 2/SiO 2 on the superconducting properties of MgB 2

NASA Astrophysics Data System (ADS)

Zhang, Y.; Zhou, S. H.; Wang, X. L.; Dou, S. X.

2008-09-01

In this paper, bulk MgB 2 was prepared by doping with nanoparticle TiO 2 surface-modified by 5-10% SiO 2. The doping ratio of TiO 2/SiO 2 to MgB 2 was 0, 5, 10, and 15 wt%. The sintering temperature varied from 650 °C to 950 °C. Quantitative X-ray diffraction (XRD) analysis was performed to obtain the lattice constants and the weight fraction of impurities using the Rietveld method. It was found that the critical temperature ( Tc) increases with the lattice constants. The critical current density ( Jc) is affected by the doping ratio and the sintering temperature. The Jc exhibited the highest value at the doping ratio of 10 wt% for 5 K and 20 K and at the doping ratio of 5 wt% for 30 K, when the sintering temperature was fixed at 750 °C. When the doping ratio was fixed at 5 wt%, the samples with the sintering temperature of 750 °C had the best Jc for 5 K and 20 K, while the sample with the sintering temperature of 850 °C exhibited the highest Jc at 30 K.

Influence of volume ratio of liquid to solid and low pouring temperature on interface structure of cast Babbitt-steel bimetal composite

NASA Astrophysics Data System (ADS)

Fathy, Naglaa; Ramadan, Mohamed

2018-05-01

The influence of volume ratio of liquid to Solid and low pouring temperature on interface structure of cast Babbitt-steel bimetal composite was evaluated for static casting technique. At low pouring temperature of 380 °C, Babbitt microstructures are improved to be finer and more globular. On the other side pouring the Babbitt at low pouring temperature of 380 °C increases the chance of present higher unbonded area percent. Increasing the volume ratio of liquid to solid decreases the Sn-Pb interface thicknesses and increases the bonded interface area. In order to optimize the production of Babbitt-steel bimetal composite at low pouring temperature, the volume ratio of liquid Babbitt to solid steel shell should be higher value that could be more than 5 depending on the extrapolation of current data presented.

Influence of Supplementation of Vegetable Oil Blends on Omega-3 Fatty Acid Production in Mortierella alpina CFR-GV15

PubMed Central

Vadivelan, Ganesan

2017-01-01

Objectives of this study were designed for improved production of mycelial omega-3 fatty acids with particular reference to EPA and DHA from the oleaginous fungus Mortierella alpina CFR-GV15 under submerged low temperatures fermentation supplemented with linseed oil and garden cress oil as an additional energy source. The fungus was grown at 20°C temperature for four days initially followed by 12°C temperature for next five days. The basal medium contained starch, yeast extract, and a blend of linseed oil (LSO) and garden cress oil (GCO) in the ratio 1 : 1. Results of the study revealed that, after nine days of total incubation period, the enhancement of biomass was up to 16.7 g/L dry weight with a total lipid content of 55.4% (v/w). Enrichment of omega-3 fatty acids indicated a significant increase in fatty acid bioconversion (ALA 32.2 ± 0.42%, EPA 7.9 ± 0.1%, and DHA 4.09 ± 0.2%) by 2.5-fold. The two-stage temperature cultivation alters the fatty acid profile due to activation of the desaturase enzyme in the cellular levels due to which arachidonic acid (AA) content reduced significantly. It can be concluded that Mortierella alpina CFR-GV15 is a fungal culture suitable for commercial production of PUFAs with enriched EPA and DHA. PMID:28466005

Programmable thermal emissivity structures based on bioinspired self-shape materials

NASA Astrophysics Data System (ADS)

Athanasopoulos, N.; Siakavellas, N. J.

2015-12-01

Programmable thermal emissivity structures based on the bioinspired self-shape anisotropic materials were developed at macro-scale, and further studied theoretically at smaller scale. We study a novel concept, incorporating materials that are capable of transforming their shape via microstructural rearrangements under temperature stimuli, while avoiding the use of exotic shape memory materials or complex micro-mechanisms. Thus, programmed thermal emissivity behaviour of a surface is achievable. The self-shape structure reacts according to the temperature of the surrounding environment or the radiative heat flux. A surface which incorporates self-shape structures can be designed to quickly absorb radiative heat energy at low temperature levels, but is simultaneously capable of passively controlling its maximum temperature in order to prevent overheating. It resembles a “game” of colours, where two or more materials coexist with different values of thermal emissivity/ absorptivity/ reflectivity. The transformation of the structure conceals or reveals one of the materials, creating a surface with programmable - and therefore, variable- effective thermal emissivity. Variable thermal emissivity surfaces may be developed with a total hemispherical emissivity ratio (ɛEff_H/ɛEff_L) equal to 28.

Temperature history of the Caribbean mixed layer as derived from sclerosponges

NASA Astrophysics Data System (ADS)

Estrella, J.; Winter, A.; Sherman, C.; Mangini, A.; Ramírez, W.

2011-12-01

We present a high resolution record of the Caribbean mixed layer temperature at different depths derived from oxygen isotopic ratios obtained from the sclerosponge Ceratoporella nicholsoni. Sclerosponges precipitate their calcium carbonate skeleton in equilibrium with their surrounding environment and are capable of living at great depths (down to 200 m). The sponges for this project were collected off Puerto Rico and St. Croix in northeastern region of the Caribbean Sea. The record obtained closest to the surface (36 m) indicates a sudden rise in sea surface temperature that started in 1866 and ended in 1877 with a total rise of 0.5 °C. At this time the rise decelerated until it finally stopped in 1935. From there onwards the record shows a declining trend that lasts until present day. We found that up to 51 % of the temperature variability in this record can be attributed to the Atlantic Multidecadal Oscillation (Trenberth and Shea, 2006). Further work is taking place on sponges located at various depths to determine the rate of expansion of the mixed layer.

Programmable thermal emissivity structures based on bioinspired self-shape materials

PubMed Central

Athanasopoulos, N.; Siakavellas, N. J.

2015-01-01

Programmable thermal emissivity structures based on the bioinspired self-shape anisotropic materials were developed at macro-scale, and further studied theoretically at smaller scale. We study a novel concept, incorporating materials that are capable of transforming their shape via microstructural rearrangements under temperature stimuli, while avoiding the use of exotic shape memory materials or complex micro-mechanisms. Thus, programmed thermal emissivity behaviour of a surface is achievable. The self-shape structure reacts according to the temperature of the surrounding environment or the radiative heat flux. A surface which incorporates self-shape structures can be designed to quickly absorb radiative heat energy at low temperature levels, but is simultaneously capable of passively controlling its maximum temperature in order to prevent overheating. It resembles a “game” of colours, where two or more materials coexist with different values of thermal emissivity/ absorptivity/ reflectivity. The transformation of the structure conceals or reveals one of the materials, creating a surface with programmable – and therefore, variable- effective thermal emissivity. Variable thermal emissivity surfaces may be developed with a total hemispherical emissivity ratio (εEff_H/εEff_L) equal to 28. PMID:26635316

Effect of Heat Treatment Temperature on Chemical Compositions of Extracted Hydroxyapatite from Bovine Bone Ash

NASA Astrophysics Data System (ADS)

Younesi, M.; Javadpour, S.; Bahrololoom, M. E.

2011-11-01

This article presents the effect of heat treating temperature on chemical composition of hydroxyapatite (HA) that was produced by burning bovine bone, and then heat treating the obtained bone ash at different temperatures in range of 600-1100 °C in air. Bone ash and the resulting white powder from heat treating were characterized by Fourier transformed infrared spectroscopy (FT-IR) and x-ray diffractometry (XRD). The FT-IR spectra confirmed that heat treating of bone ash at temperature of 800 °C removed the total of organic substances. x-ray diffraction analysis showed that the white powder was HA and HA was the only crystalline phase indicated in heat treating product. x-ray fluorescence analyses revealed that calcium and phosphorous were the main elements and magnesium and sodium were minor impurities of produced powder at 800 °C. The results of the energy dispersive x-ray analysis showed that Ca/P ratio in produced HA varies in range of 1.46-2.01. The resulting material was found to be thermally stable up to 1100 °C.

Bio-hydrolysis and bio-hydrogen production from food waste by thermophilic and hyperthermophilic anaerobic process.

PubMed

Algapani, Dalal E; Qiao, Wei; Su, Min; di Pumpo, Francesca; Wandera, Simon M; Adani, Fabrizio; Dong, Renjie

2016-09-01

High-temperature pretreatment plays a key role in the anaerobic digestion of food waste (FW). However, the suitable temperature is not yet determined. In this work, a long-term experiment was conducted to compare hydrolysis, acidogenesis, acetogenesis, and hydrogen production at 55°C and 70°C, using real FW in CSTR reactors. The results obtained indicated that acidification was the rate-limiting step at both temperatures with similar process kinetics characterizations. However, the thermophilic pretreatment was more advantageous than the hyperthermophilic with suspended solids solubilization of 47.7% and 29.5% and total VFA vs. soluble COD ratio of 15.2% and 4.9%, for thermophilic and hyperthermophilic treatment, respectively, with a hydrolytic reaction time (HRT) of 10days and an OLR of 14kgCOD/m(3)d. Moreover, stable hydrogen yield (70.7ml-H2/gVSin) and content in off gas (58.6%) was achieved at HRT 5days, pH 5.5, and temperature of 55°C, as opposed to 70°C. Copyright © 2016 Elsevier Ltd. All rights reserved.

Associations of infant subcutaneous fat mass with total and abdominal fat mass at school-age. The Generation R Study

PubMed Central

Santos, Susana; Gaillard, Romy; Oliveira, Andreia; Barros, Henrique; Abrahamse-Berkeveld, Marieke; van der Beek, Eline M; Hofman, Albert; Jaddoe, Vincent WV

2017-01-01

Background Skinfold thickness enables the measurement of overall and regional subcutaneous fatness in infancy and may be associated with total and abdominal body fat in later childhood. We examined the associations of subcutaneous fat in infancy with total and abdominal fat at school-age. Methods In a population-based prospective cohort study among 821 children, we calculated total subcutaneous fat (sum of biceps, triceps, suprailiacal and subscapular skinfold thicknesses) and central-to-total subcutaneous fat ratio (sum of suprailiacal and subscapular skinfold thicknesses/total subcutaneous fat) at 1.5 and 24 months. At 6 years, we measured fat mass index (total fat/height3), central-to-total fat ratio (trunk fat/total fat) and android-to-gynoid fat ratio (android fat/gynoid fat) by dual-energy X-ray absorptiometry and preperitoneal fat mass area by abdominal ultrasound. Results Central-to-total subcutaneous fat ratio at 1.5 months was positively associated with fat mass index and central-to-total fat ratio at 6 years, whereas both total and central-to-total subcutaneous fat ratio at 24 months were positively associated with all childhood adiposity measures (p<0.05). A 1-standard-deviation scores higher total subcutaneous fat at 24 months was associated with an increased risk of childhood overweight (Odds Ratio 1.70 [95% Confidence Interval 1.36, 2.12]). These associations were weaker than those for body mass index and stronger among girls than boys. Conclusions Subcutaneous fat in infancy is positively associated with total and abdominal fat at school-age. Our results also suggest that skinfold thicknesses add little value to estimate later body fat, as compared to body mass index. PMID:27225335

Associations of Infant Subcutaneous Fat Mass with Total and Abdominal Fat Mass at School-Age: The Generation R Study.

PubMed

Santos, Susana; Gaillard, Romy; Oliveira, Andreia; Barros, Henrique; Abrahamse-Berkeveld, Marieke; van der Beek, Eline M; Hofman, Albert; Jaddoe, Vincent W V

2016-09-01

Skinfold thickness enables the measurement of overall and regional subcutaneous fatness in infancy and may be associated with total and abdominal body fat in later childhood. We examined the associations of subcutaneous fat in infancy with total and abdominal fat at school-age. In a population-based prospective cohort study among 821 children, we calculated total subcutaneous fat (sum of biceps, triceps, suprailiacal, and subscapular skinfold thicknesses) and central-to-total subcutaneous fat ratio (sum of suprailiacal and subscapular skinfold thicknesses/total subcutaneous fat) at 1.5 and 24 months. At 6 years, we measured fat mass index (total fat/height(3) ), central-to-total fat ratio (trunk fat/total fat), and android-to-gynoid fat ratio (android fat/gynoid fat) by dual-energy X-ray absorptiometry and preperitoneal fat mass area by abdominal ultrasound. Central-to-total subcutaneous fat ratio at 1.5 months was positively associated with fat mass index and central-to-total fat ratio at 6 years, whereas both total and central-to-total subcutaneous fat ratio at 24 months were positively associated with all childhood adiposity measures. A 1-standard-deviation scores higher total subcutaneous fat at 24 months was associated with an increased risk of childhood overweight (odds ratio 1.70, 95% confidence interval 1.36, 2.12). These associations were weaker than those for body mass index and stronger among girls than boys. Subcutaneous fat in infancy is positively associated with total and abdominal fat at school-age. Our results also suggest that skinfold thicknesses add little value to estimate later body fat, as compared with body mass index. © 2016 John Wiley & Sons Ltd.

Temperature-induced sex reversal is not responsible for sex-ratio distortions in grayling Thymallus thymallus or brown trout Salmo trutta.

PubMed

Pompini, M; Buser, A M; Thali, M R; Von Siebenthal, B A; Nusslé, S; Guduff, S; Wedekind, C

2013-08-01

On the basis of the experiments carried out over various years, it was concluded that (1) grayling Thymallus thymallus and brown trout Salmo trutta are resistant to temperature-induced sex reversal at ecologically relevant temperatures, (2) environmental sex reversal is unlikely to cause the persistent sex ratio distortion observed in at least one of the study populations and (3) sex-specific tolerance of temperature-related stress may be the cause of distorted sex ratios in populations of T. thymallus or S. trutta. © 2013 The Fisheries Society of the British Isles.

Optimization of lipid extraction from Salvinia molesta for biodiesel production using RSM and its FAME analysis.

PubMed

Mubarak, M; Shaija, A; Suchithra, T V

2016-07-01

The higher areal productivity and lipid content of microalgae and aquatic weed makes them the best alternative feedstocks for biodiesel production. Hence, an efficient and economic method of extracting lipid or oil from aquatic weed, Salvinia molesta is an important step towards biodiesel production. Since Salvinia molesta is an unexplored feedstock, its total lipid content was first measured as 16 % using Bligh and Dyer's method which was quite sufficient for further investigation. For extracting more amount of lipid from Salvinia molesta, methanol: chloroform in the ratio 2:1 v/v was identified as the most suitable solvent system using Soxhlet apparatus. Based on the literature and the preliminary experimentations, parameters such as solvent to biomass ratio, temperature, and time were identified as significant for lipid extraction. These parameters were then optimized using response surface methodology with central composite design, where experiments were performed using twenty combinations of these extraction parameters with Minitab-17 software. A lipid yield of 92.4 % from Salvinia molesta was obtained with Soxhlet apparatus using methanol and chloroform (2:1 v/v) as solvent system, at the optimized conditions of temperature (85 °C), solvent to biomass ratio (20:1), and time (137 min), whereas a predicted lipid yield of 93.5 % with regression model. Fatty acid methyl ester (FAME) analysis of S. molesta lipid using gas chromatograph mass spectroscopy (GCMS) with flame ionization detector showed that fatty acids such as C16:0, C16:1, C18:1, and C18:2 contributed more than 9 % weight of total fatty acids. FAME consisted of 56.32, 28.08, and 15.59 % weight of monounsaturated, saturated, and polyunsaturated fatty acids, respectively. Higher cetane number and superior oxidation stability of S. molesta FAME could be attributed to its higher monounsaturated content and lower polyunsaturated content as compared to biodiesels produced from C. vulgaris, Sunflower, and Jatropha.

Lipozyme RM IM-catalyzed acidolysis of Cinnamomum camphora seed oil with oleic acid to produce human milk fat substitutes enriched in medium-chain fatty acids.

PubMed

Zou, Xian-Guo; Hu, Jiang-Ning; Zhao, Man-Li; Zhu, Xue-Mei; Li, Hong-Yan; Liu, Xiao-Ru; Liu, Rong; Deng, Ze-Yuan

2014-10-29

In the present study, a human milk fat substitute (HMFS) enriched in medium-chain fatty acids (MCFAs) was synthesized through acidolysis reaction from Cinnamomum camphora seed oil (CCSO) with oleic acid in a solvent-free system. A commercial immobilized lipase, Lipozyme RM IM, from Rhizomucor miehei, was facilitated as a biocatalyst. Effects of different reaction conditions, including substrate molar ratio, enzyme concentration, reaction temperature, and reaction time were investigated using response surface methodology (RSM) to obtain the optimal oleic acid incorporation. After optimization, results showed that the maximal incorporation of oleic acid into HMFS was 59.68%. Compared with CCSO, medium-chain fatty acids at the sn-2 position of HMFS accounted for >70%, whereas oleic acid was occupied predominantly at the sn-1,3 position (78.69%). Meanwhile, triacylglycerol (TAG) components of OCO (23.93%), CCO (14.94%), LaCO (13.58%), OLaO (12.66%), and OOO (11.13%) were determined as the major TAG species in HMFS. The final optimal reaction conditions were carried out as follows: substrate molar ratio (oleic acid/CCSO), 5:1; enzyme concentration, 12.5% (w/w total reactants); reaction temperature, 60 °C; and reaction time, 28 h. The reusability of Lipozyme RM IM in the acidolysis reaction was also evaluated, and it was found that it could be reused up to 9 times without significant loss of activities. Urea inclusion method was used to separate and purify the synthetic product. As the ratio of HMFS/urea increased to 1:2, the acid value lowered to the minimum. In a scale-up experiment, the contents of TAG and total tocopherols in HMFS (modified CCSO) were 77.28% and 12.27 mg/100 g, respectively. All of the physicochemical indices of purified product were within food standards. Therefore, such a MCFA-enriched HMFS produced by using the acidolysis method might have potential application in the infant formula industry.

Sex Ratios at Birth and Environmental Temperatures

NASA Astrophysics Data System (ADS)

Lerchl, Alexander

The relationship between average monthly air temperature and sex ratios at birth (SRB) was analyzed for children born in Germany during the period 1946-1995. Both the absolute temperature and - more markedly - the monthly temperature deviations from the overall mean were significantly positively correlated with the SRB (P<0.01) when temperatures were time-lagged against the SRB data by -10 or -11months. It is concluded that the sex of the offspring is partially determined by environmental temperatures prior to conception.

Noble Gas geochemistry of the newly discovered hydrothermal fields in the Gulf of California: preliminary He-isotope ratios from the Alarcon Rise and Pescadero basin vent sites

NASA Astrophysics Data System (ADS)

Spelz, R. M.; Lupton, J. E.; Evans, L. J.; Zierenberg, R. A.; Clague, D. A.; Neumann, F.; Paduan, J. B.

2015-12-01

Numerous submarine deep-sea hydrothermal vents related to volcanic activity of the East Pacific Rise (EPR) are situated along the Pacific margins of Mexico. Until recently, active hydrothermal venting was unknown between the Guaymas Basin and 21°N on the EPR. MBARI's recent oceanographic surveys have added 7 new active vent sites. In this study, we aimed to sample the high-temperature hydrothermal fluids emanating from two distinct vent sites, named Meyibo and Auka, located in the Alarcon Rise and Pescadero Basin, respectively. Mantle-derived He have long been identified in hydrothermal fluid releases. The presence of He in aqueous fluids with 3He/4He ratios greater than in-situ production values (~0.05 RA, where RA = air He or 1.4 x 10-6) indicates the presence of mantle-derived melts. Preliminary analyses of He-isotope ratios derived from the newly discovered Meyibo and Auka hydrothermal fields show high 3He/4He ratios (~8RA), typical of MORB's. Auka vent field, characterized by chimneys composed of light carbonate minerals and oil-like hydrocarbons, and temperatures between 250-290oC, show average values of ~7.87RA. In contrast, the black-smokers at the Meyibo field, composed of dark sulfide minerals and temperatures over 350oC, yielded a higher He ratio of ~8.24RA. Recently, it has become clear that regional maximum mantle He values correlate with the velocity structure in the mantle, therefore, He has the potential to map regions of the underlying mantle that are undergoing partial melting. Seismic records could then be compared with the geochemical He ratio signal and supply information regarding tectonics and other processes involved in the generation of these gases. The data presented here will be completing a totally new inventory of He results from hydrothermal vents in the EPR and fault-termination basins distributed along the P-NA plate boundary in the Gulf of California. The results will be further coupled with the analysis of other geochemical indicators of mantle degassing to assess the relationship between He-isotopes and mantle velocity structure in the region.

Isolating and evaluating lactic acid bacteria strains for effectiveness on silage quality at low temperatures on the Tibetan Plateau.

PubMed

Wang, Siran; Yuan, Xianjun; Dong, Zhihao; Li, Junfeng; Shao, Tao

2017-11-01

Four lactic acid bacteria (LAB) strains isolated from straw silages on the Tibetan Plateau were characterized, and their effects on the fermentation quality of Italian ryegrass (Lolium multiflorum Lam.) at different temperatures (10°C, 15°C and 25°C) were studied. These LAB isolates were evaluated using the acids production ability test, morphological observation, Gram staining, physiological, biochemical and acid tolerance tests. All the isolates (M1, LM8, LO7 and LOG9) could grow at 5-20°C, pH 3.5-7.0 and NaCl (3.0%, 6.5%). Strains M1, LM8, LO7 and LOG9 were identified as Lactobacillus plantarum, L. coryniformis, Pediococcus pentosaceus and P. acidilactici, respectively, by sequencing 16S ribosomal DNA. The four isolates were added to Italian ryegrass for ensiling for 30 days at various temperatures. Compared with the corresponding control, inoculating with isolates M1, LM8 and LO7 could improve the silage quality of Italian ryegrass at low temperatures, indicated by significantly (P < 0.05) higher lactic acid (LA) contents and ratios of lactic acid/acetic acid (LA/AA), and significantly (P < 0.05) lower pH and ammonia nitrogen/total nitrogen (AN/TN). Compared with other isolates, LM8 performed better at 10°C and 15°C, indicated by the higher (P < 0.05) LA content and ratio of LA/AA, and the lower (P < 0.05) pH and AN/TN. © 2017 Japanese Society of Animal Science.

Effect of high temperature on grain filling period, yield, amylose content and activity of starch biosynthesis enzymes in endosperm of basmati rice.

PubMed

Ahmed, Nisar; Tetlow, Ian J; Nawaz, Sehar; Iqbal, Ahsan; Mubin, Muhammad; Nawaz ul Rehman, Muhammad Shah; Butt, Aisha; Lightfoot, David A; Maekawa, Masahiko

2015-08-30

High temperature during grain filling affects yield, starch amylose content and activity of starch biosynthesis enzymes in basmati rice. To investigate the physiological mechanisms underpinning the effects of high temperature on rice grain, basmati rice was grown under two temperature conditions - 32 and 22 °C - during grain filling. High temperature decreased the grain filling period from 32 to 26 days, reducing yield by 6%, and caused a reduction in total starch (3.1%) and amylose content (22%). Measurable activities of key enzymes involved in sucrose to starch conversion, sucrose synthase, ADP-glucose pyrophosphorylase, starch phosphorylase and soluble starch synthase in endosperms developed at 32 °C were lower than those at 22 °C compared with similar ripening stage on an endosperm basis. In particular, granule-bound starch synthase (GBSS) activity was significantly lower than corresponding activity in endosperms developing at 22 °C during all developmental stages analyzed. Results suggest changes in amylose/amylopectin ratio observed in plants grown at 32 °C was attributable to a reduction in activity of GBSS, the sole enzyme responsible for amylose biosynthesis. © 2014 Society of Chemical Industry.

Structural, electronic, elastic, thermoelectric and thermodynamic properties of the NbMSb half heusler (M=Fe, Ru, Os) compounds with first principle calculations

NASA Astrophysics Data System (ADS)

Abid, O. Miloud; Menouer, S.; Yakoubi, A.; Khachai, H.; Omran, S. Bin; Murtaza, G.; Prakash, Deo; Khenata, R.; Verma, K. D.

2016-05-01

The structural, electronic, elastic, thermoelectric and thermodynamic properties of NbMSb (M = Fe, Ru, Os) half heusler compounds are reported. The full-potential linearized augmented plane wave (FP-LAPW) plus local orbital (lo) method, based on the density functional theory (DFT) was employed for the present study. The equilibrium lattice parameter results are in good compliance with the available experimental measurements. The electronic band structure and Boltzmann transport calculations indicated a narrow indirect energy band gap for the compound having electronic structure favorable for thermoelectric performance as well as with substantial thermopowers at temperature ranges from 300 K to 800 K. Furthermore, good potential for thermoelectric performance (thermopower S ≥ 500 μeV) was found at higher temperature. In addition, the analysis of the charge density, partial and total densities of states (DOS) of three compounds demonstrate their semiconducting, ionic and covalent characters. Conversely, the calculated values of the Poisson's ratio and the B/G ratio indicate their ductile makeup. The thermal properties of the compounds were calculated by quasi-harmonic Debye model as implemented in the GIBBS code.

Effects of selected lactic acid bacteria on the characteristics of amaranth sourdough.

PubMed

Jekle, Mario; Houben, Andreas; Mitzscherling, Martin; Becker, Thomas

2010-10-01

As the processing of amaranth in baked goods is challenging, the use of sourdough fermentation is a promising possibility to exploit the advantages of this raw material. In this study the fermentation properties of Lactobacillus plantarum, Lactobacillus paralimentarius and Lactobacillus helveticus in amaranth-based sourdough were examined in order to validate them as starter cultures. pH, total titratable acidity (TTA) and lactic/acetic acid ratio of the sourdough and sensory properties of the resulting wheat bread were evaluated using fermentation temperatures of 30 and 35 °C. While fermentation pH, TTA and lactic acid concentration showed small variations with the use of L. plantarum and L. paralimentarius, L. helveticus reached the most intensive acidification after initial adaptation to the substrate. Acetic acid production was independent of lactic acid metabolism. Furthermore, the lactic/acetic acid ratio exceeded recommendation by 10-35 times (fermentation quotient 25-82). Sensory evaluation showed no significant differences between the two fermentation temperatures but differences among the three micro-organisms. The results provide relevant information on the fermentation properties required of a customised starter for amaranth flour. Copyright © 2010 Society of Chemical Industry.

Laser Raman Diagnostics in Subsonic and Supersonic Turbulent Jet Diffusion Flames.

NASA Astrophysics Data System (ADS)

Cheng, Tsarng-Sheng

1991-02-01

UV spontaneous vibrational Raman scattering combined with laser-induced predissociative fluorescence (LIPF) is developed for temperature and multi-species concentration measurements. For the first time, simultaneous measurements of temperature, major species (H_2, O_2, N_2, H_2O), and minor species (OH) concentrations are made with a "single" narrowband KrF excimer laser in subsonic and supersonic lifted turbulent hydrogen-air diffusion flames. The UV Raman system is calibrated with a flat -flame diffusion burner operated at several known equivalence ratios from fuel-lean to fuel-rich. Temperature measurements made by the ratio of Stokes/anti-Stokes signal and by the ideal gas law are compared. Single-shot uncertainties for temperature and concentration measurements are analyzed with photon statistics. Calibration constants and bandwidth factors are used in the data reduction program to arrive at temperature and species concentration measurements. UV Raman measurements in the subsonic lifted turbulent diffusion flame indicate that fuel and oxidizer are in rich, premixed, and unignited conditions in the center core of the lifted flame base. The unignited mixtures are due to rapid turbulent mixing that affects chemical reaction. Combustion occurs in an intermittent annular turbulent flame brush with strong finite-rate chemistry effects. The OH radical exists in sub-equilibrium and super-equilibrium concentrations. Major species and temperature are found with non-equilibrium values. Further downstream the super-equilibrium OH radicals decay toward equilibrium through slow three-body recombination reactions. In the supersonic lifted flame, a little reaction occurs upstream of the flame base, due to shock wave interactions and mixing with hot vitiated air. The strong turbulent mixing and total enthalpy fluctuations lead to temperature, major, and minor species concentrations with non-equilibrium values. Combustion occurs farther downstream of the lifted region. Slow three-body recombination reactions result in super-equilibrium OH concentrations that depress temperature below the equilibrium values. Near the equilibrium region, ambient air entrainment contaminates flame properties. These simultaneous measurements of temperature and multi-species concentrations allow a better understanding of the complex turbulence-chemistry interactions and provide information for the input and validation of CFD models.

The Spectral Energy Distributions and Infrared Luminosities of z ≈ 2 Dust-obscured Galaxies from Herschel and Spitzer

NASA Astrophysics Data System (ADS)

Melbourne, J.; Soifer, B. T.; Desai, Vandana; Pope, Alexandra; Armus, Lee; Dey, Arjun; Bussmann, R. S.; Jannuzi, B. T.; Alberts, Stacey

2012-05-01

Dust-obscured galaxies (DOGs) are a subset of high-redshift (z ≈ 2) optically-faint ultra-luminous infrared galaxies (ULIRGs, e.g., L IR > 1012 L ⊙). We present new far-infrared photometry, at 250, 350, and 500 μm (observed-frame), from the Herschel Space Telescope for a large sample of 113 DOGs with spectroscopically measured redshifts. Approximately 60% of the sample are detected in the far-IR. The Herschel photometry allows the first robust determinations of the total infrared luminosities of a large sample of DOGs, confirming their high IR luminosities, which range from 1011.6 L ⊙ 1013 L ⊙. The rest-frame near-IR (1-3 μm) spectral energy distributions (SEDs) of the Herschel-detected DOGs are predictors of their SEDs at longer wavelengths. DOGs with "power-law" SEDs in the rest-frame near-IR show observed-frame 250/24 μm flux density ratios similar to the QSO-like local ULIRG, Mrk 231. DOGs with a stellar "bump" in their rest-frame near-IR show observed-frame 250/24 μm flux density ratios similar to local star-bursting ULIRGs like NGC 6240. None show 250/24 μm flux density ratios similar to extreme local ULIRG, Arp 220; though three show 350/24 μm flux density ratios similar to Arp 220. For the Herschel-detected DOGs, accurate estimates (within ~25%) of total IR luminosity can be predicted from their rest-frame mid-IR data alone (e.g., from Spitzer observed-frame 24 μm luminosities). Herschel-detected DOGs tend to have a high ratio of infrared luminosity to rest-frame 8 μm luminosity (the IR8 = L IR(8-1000 μm)/νL ν(8 μm) parameter of Elbaz et al.). Instead of lying on the z = 1-2 "infrared main sequence" of star-forming galaxies (like typical LIRGs and ULIRGs at those epochs) the DOGs, especially large fractions of the bump sources, tend to lie in the starburst sequence. While, Herschel-detected DOGs are similar to scaled up versions of local ULIRGs in terms of 250/24 μm flux density ratio, and IR8, they tend to have cooler far-IR dust temperatures (20-40 K for DOGs versus 40-50 K for local ULIRGs) as measured by the rest-frame 80/115 μm flux density ratios (e.g., observed-frame 250/350 μm ratios at z = 2). DOGs that are not detected by Herschel appear to have lower observed-frame 250/24 μm ratios than the detected sample, either because of warmer dust temperatures, lower IR luminosities, or both. Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA.

THE SPECTRAL ENERGY DISTRIBUTIONS AND INFRARED LUMINOSITIES OF z Almost-Equal-To 2 DUST-OBSCURED GALAXIES FROM Herschel AND Spitzer

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

Melbourne, J.; Soifer, B. T.; Desai, Vandana

Dust-obscured galaxies (DOGs) are a subset of high-redshift (z Almost-Equal-To 2) optically-faint ultra-luminous infrared galaxies (ULIRGs, e.g., L{sub IR} > 10{sup 12} L{sub Sun} ). We present new far-infrared photometry, at 250, 350, and 500 {mu}m (observed-frame), from the Herschel Space Telescope for a large sample of 113 DOGs with spectroscopically measured redshifts. Approximately 60% of the sample are detected in the far-IR. The Herschel photometry allows the first robust determinations of the total infrared luminosities of a large sample of DOGs, confirming their high IR luminosities, which range from 10{sup 11.6} L{sub Sun} 10{sup 13} L{sub Sun }. Themore » rest-frame near-IR (1-3 {mu}m) spectral energy distributions (SEDs) of the Herschel-detected DOGs are predictors of their SEDs at longer wavelengths. DOGs with 'power-law' SEDs in the rest-frame near-IR show observed-frame 250/24 {mu}m flux density ratios similar to the QSO-like local ULIRG, Mrk 231. DOGs with a stellar 'bump' in their rest-frame near-IR show observed-frame 250/24 {mu}m flux density ratios similar to local star-bursting ULIRGs like NGC 6240. None show 250/24 {mu}m flux density ratios similar to extreme local ULIRG, Arp 220; though three show 350/24 {mu}m flux density ratios similar to Arp 220. For the Herschel-detected DOGs, accurate estimates (within {approx}25%) of total IR luminosity can be predicted from their rest-frame mid-IR data alone (e.g., from Spitzer observed-frame 24 {mu}m luminosities). Herschel-detected DOGs tend to have a high ratio of infrared luminosity to rest-frame 8 {mu}m luminosity (the IR8 = L{sub IR}(8-1000 {mu}m)/{nu}L{sub {nu}}(8 {mu}m) parameter of Elbaz et al.). Instead of lying on the z = 1-2 'infrared main sequence' of star-forming galaxies (like typical LIRGs and ULIRGs at those epochs) the DOGs, especially large fractions of the bump sources, tend to lie in the starburst sequence. While, Herschel-detected DOGs are similar to scaled up versions of local ULIRGs in terms of 250/24 {mu}m flux density ratio, and IR8, they tend to have cooler far-IR dust temperatures (20-40 K for DOGs versus 40-50 K for local ULIRGs) as measured by the rest-frame 80/115 {mu}m flux density ratios (e.g., observed-frame 250/350 {mu}m ratios at z = 2). DOGs that are not detected by Herschel appear to have lower observed-frame 250/24 {mu}m ratios than the detected sample, either because of warmer dust temperatures, lower IR luminosities, or both.« less

Do factors related to combustion-based sources explain ...

EPA Pesticide Factsheets

Introduction: Spatial heterogeneity of effect estimates in associations between PM2.5 and total non-accidental mortality (TNA) in the United States (US), is an issue in epidemiology. This study uses rate ratios generated from the Multi-City/Multi-Pollutant study (1999-2005) for 313 core-based statistical areas (CBSA) and their metropolitan divisions (MD) to examine combustion-based sources of heterogeneity.Methods: For CBSA/MDs, area-specific log rate ratios (betas) were derived from a model adjusting for time, an interaction with age-group, day of week, and natural splines of current temperature, current dew point, and unconstrained temperature at lags 1, 2, and 3. We assessed the heterogeneity in the betas by linear regression with inverse variance weights, using average NO2, SO2, and CO, which may act as a combustion source proxy, and these pollutants’ correlations with PM2.5. Results: We found that weighted mean PM2.5 association (0.96 percent increase in total non-accidental mortality for a 10 µg/m3 increment in PM2.5) increased by 0.26 (95% confidence interval 0.08 , 0.44) for an interquartile change (0.2) in the correlation of SO2 and PM2.5., but betas showed less dependence on the annual averages of SO2 or NO2. Spline analyses suggest departures from linearity, particularly in a model that examined correlations between PM2.5 and CO.Conclusions: We conclude that correlations between SO2 and PM2.5 as an indicator of combustion sources explains some hete

Response Surface Methodology Optimization of Ultrasonic-Assisted Extraction of Acer Truncatum Leaves for Maximal Phenolic Yield and Antioxidant Activity.

PubMed

Yang, Lingguang; Yin, Peipei; Fan, Hang; Xue, Qiang; Li, Ke; Li, Xiang; Sun, Liwei; Liu, Yujun

2017-02-04

This study is the first to report the use of response surface methodology to improve phenolic yield and antioxidant activity of Acer truncatum leaves extracts (ATLs) obtained by ultrasonic-assisted extraction. The phenolic composition in ATLs extracted under the optimized conditions were characterized by UPLC-QTOF-MS/MS. Solvent and extraction time were selected based on preliminary experiments, and a four-factors-three-levels central composite design was conducted to optimize solvent concentration ( X ₁), material-to-liquid ratio ( X ₂), ultrasonic temperature ( X ₃) and power ( X ₄) for an optimal total phenol yield ( Y ₁) and DPPH• antioxidant activity ( Y ₂). The results showed that the optimal combination was ethanol:water ( v : v ) 66.21%, material-to-liquid ratio 1:15.31 g/mL, ultrasonic bath temperature 60 °C, power 267.30 W, and time 30 min with three extractions, giving a maximal total phenol yield of 7593.62 mg gallic acid equivalent/100 g d.w. and a maximal DPPH• antioxidant activity of 74,241.61 μmol Trolox equivalent/100 g d.w. Furthermore, 22 phenolics were first identified in ATL extract obtained under the optimized conditions, indicating that gallates, gallotannins, quercetin, myricetin and chlorogenic acid derivatives were the main phenolic components in ATL. What's more, a gallotannins pathway existing in ATL from gallic acid to penta- O -galloylglucoside was proposed. All these results provide practical information aiming at full utilization of phenolics in ATL, together with fundamental knowledge for further research.

Effect of powder to liquid ratio on tensile strength and glass transition temperature of alumina filled poly methyl methacrylate (PMMA) denture base material.

PubMed

Mohamed, S H; Arifin, A; Mohd Ishak, Z A; Nizam, A; Samsudin, A R

2004-05-01

The aim of this study was to evaluate the mechanical properties and glass transition temperature (Tg) of a denture base material prepared from high molecular weight poly methyl methacrylate (PMMA) and alumina (Al2O3). The glass transition temperature was studied by using differential scanning calorimetry (DSC). The effect of powder-to-liquid ratio was investigated. The result showed that the tensile properties and the Tg were slightly effected by the powder-to-liquid ratio. The ratio of 2.2:1 by weight of powder to liquid was found to be the best ratio for mixing the material to give the best result in this formulation.

Effect of early feed restriction on physiological responses, performance and ascites incidence in broiler chickens raised in normal or cold environment.

PubMed

Mohammadalipour, R; Rahmani, H R; Jahanian, R; Riasi, A; Mohammadalipour, M; Nili, N

2017-02-01

Intensive selection of broilers for faster growth and better feed efficiency resulted in greater susceptibility to metabolic disorders such as ascites syndrome, which is one of the major causes of mortality and economic loss in broiler industry. Whereas cool temperature is one of the primary triggers for ascites, early feed restriction (FDR) significantly alleviates its incidence and mortality. However, little is known about effects of FDR, cold environmental temperature and their interaction on physiological responses in broiler chickens. For this purpose, 320 one-day-old male broilers were divided into two treatment groups of Ad libitum (Ad) and feed restricted (FR) with eight pen replicates each. Chickens in FR group underwent feed access limitation from days 7 to 14 of age. On day 21 half of the birds (four pens) in each group exposed to the cold temperature (CT) and the other half (four pens) continued at normal temperature (NT). Average daily feed intake, average daily weight gain and feed conversion ratio (FCR) were measured at days 7, 14, 21, 28 and 42. At 39 and 46 days of age two chicks with a BW around the pen average were selected from each pen and slaughtered after collecting blood samples. Then, relative weight of internal organs and right ventricle weight per total ventricle weight (RV : TV) ratio were calculated. Compared with NT group, CT birds had higher daily feed intake and FCR (P<0.05) from day 28 to 42. Cumulative ascites mortality in CT chickens was higher (P<0.001) than NT chicks. Within the CT group, ascites mortality in FR chickens was reduced (P<0.001) to 1.25% compared with 8.75% in Ad chicks. Birds in CT group had significantly (P<0.05) thicker right ventricle and greater relative weight of heart, hematocrit and triiodothyronine concentration. However, none of these parameters were affected by FDR. Under cold stress conditions, FDR reduced activity of alanine aminotransferase and aspartate aminotransferase (P<0.05). Serum triglyceride, cholesterol, high-density lipoprotein and total protein were not influenced by either temperature or feeding regimen. In conclusion, these findings suggest that FDR reduces ascites incidence mainly by allowing better development of internal organs, which helps them to cope with the high metabolic pressure and suffer less damage.

CLASH-X: A Comparison of Lensing and X-Ray Techniques for Measuring the Mass Profiles of Galaxy Clusters

NASA Astrophysics Data System (ADS)

Donahue, Megan; Voit, G. Mark; Mahdavi, Andisheh; Umetsu, Keiichi; Ettori, Stefano; Merten, Julian; Postman, Marc; Hoffer, Aaron; Baldi, Alessandro; Coe, Dan; Czakon, Nicole; Bartelmann, Mattias; Benitez, Narciso; Bouwens, Rychard; Bradley, Larry; Broadhurst, Tom; Ford, Holland; Gastaldello, Fabio; Grillo, Claudio; Infante, Leopoldo; Jouvel, Stephanie; Koekemoer, Anton; Kelson, Daniel; Lahav, Ofer; Lemze, Doron; Medezinski, Elinor; Melchior, Peter; Meneghetti, Massimo; Molino, Alberto; Moustakas, John; Moustakas, Leonidas A.; Nonino, Mario; Rosati, Piero; Sayers, Jack; Seitz, Stella; Van der Wel, Arjen; Zheng, Wei; Zitrin, Adi

2014-10-01

We present profiles of temperature, gas mass, and hydrostatic mass estimated from new and archival X-ray observations of CLASH clusters. We compare measurements derived from XMM and Chandra observations with one another and compare both to gravitational lensing mass profiles derived with CLASH Hubble Space Telescope and Subaru Telescope lensing data. Radial profiles of Chandra and XMM measurements of electron density and enclosed gas mass are nearly identical, indicating that differences in hydrostatic masses inferred from X-ray observations arise from differences in gas-temperature measurements. Encouragingly, gas temperatures measured in clusters by XMM and Chandra are consistent with one another at ~100-200 kpc radii, but XMM temperatures systematically decline relative to Chandra temperatures at larger radii. The angular dependence of the discrepancy suggests that additional investigation on systematics such as the XMM point-spread function correction, vignetting, and off-axis responses is yet required. We present the CLASH-X mass-profile comparisons in the form of cosmology-independent and redshift-independent circular-velocity profiles. We argue that comparisons of circular-velocity profiles are the most robust way to assess mass bias. Ratios of Chandra hydrostatic equilibrium (HSE) mass profiles to CLASH lensing profiles show no obvious radial dependence in the 0.3-0.8 Mpc range. However, the mean mass biases inferred from the weak-lensing (WL) and SaWLens data are different. As an example, the weighted-mean value at 0.5 Mpc is langbrang = 0.12 for the WL comparison and langbrang = -0.11 for the SaWLens comparison. The ratios of XMM HSE mass profiles to CLASH lensing profiles show a pronounced radial dependence in the 0.3-1.0 Mpc range, with a weighted mean mass bias value rising to langbrang >~ 0.3 at ~1 Mpc for the WL comparison and langbrang ≈ 0.25 for the SaWLens comparison. The enclosed gas mass profiles from both Chandra and XMM rise to a value ≈1/8 times the total-mass profiles inferred from lensing at ≈0.5 Mpc and remain constant outside of that radius, suggesting that M gas × 8 profiles may be an excellent proxy for total-mass profiles at >~ 0.5 Mpc in massive galaxy clusters.

CLASH-X: A comparison of lensing and X-ray techniques for measuring the mass profiles of galaxy clusters

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

Donahue, Megan; Voit, G. Mark; Hoffer, Aaron

2014-10-20

We present profiles of temperature, gas mass, and hydrostatic mass estimated from new and archival X-ray observations of CLASH clusters. We compare measurements derived from XMM and Chandra observations with one another and compare both to gravitational lensing mass profiles derived with CLASH Hubble Space Telescope and Subaru Telescope lensing data. Radial profiles of Chandra and XMM measurements of electron density and enclosed gas mass are nearly identical, indicating that differences in hydrostatic masses inferred from X-ray observations arise from differences in gas-temperature measurements. Encouragingly, gas temperatures measured in clusters by XMM and Chandra are consistent with one another atmore » ∼100-200 kpc radii, but XMM temperatures systematically decline relative to Chandra temperatures at larger radii. The angular dependence of the discrepancy suggests that additional investigation on systematics such as the XMM point-spread function correction, vignetting, and off-axis responses is yet required. We present the CLASH-X mass-profile comparisons in the form of cosmology-independent and redshift-independent circular-velocity profiles. We argue that comparisons of circular-velocity profiles are the most robust way to assess mass bias. Ratios of Chandra hydrostatic equilibrium (HSE) mass profiles to CLASH lensing profiles show no obvious radial dependence in the 0.3-0.8 Mpc range. However, the mean mass biases inferred from the weak-lensing (WL) and SaWLens data are different. As an example, the weighted-mean value at 0.5 Mpc is (b) = 0.12 for the WL comparison and (b) = –0.11 for the SaWLens comparison. The ratios of XMM HSE mass profiles to CLASH lensing profiles show a pronounced radial dependence in the 0.3-1.0 Mpc range, with a weighted mean mass bias value rising to (b) ≳ 0.3 at ∼1 Mpc for the WL comparison and (b) ≈ 0.25 for the SaWLens comparison. The enclosed gas mass profiles from both Chandra and XMM rise to a value ≈1/8 times the total-mass profiles inferred from lensing at ≈0.5 Mpc and remain constant outside of that radius, suggesting that M {sub gas} × 8 profiles may be an excellent proxy for total-mass profiles at ≳ 0.5 Mpc in massive galaxy clusters.« less

Sea-cave temperature measurements and amino acid geochronology of British Late Pleistocene Sea stands

USGS Publications Warehouse

Hollin, John T.; Smith, Franklin L.; Renouf, John T.; Jenkins, D. Graham

1993-01-01

‘Calibrating’ amino acid ratios with uranium-series dates requires an accurate knowledge of current mean annual temperatures (CMATs) over the region studied. To measure these, test-tube sized ‘diffusion sensors’ were emplaced for 1 year (in 1984, 1985 and 1986), both outside and inside Minchin Hole sea-cave in South Wales and Belle Hougue sea-cave in Jersey, both of which have yielded Oxygen Isotope Substage 5e uranium-series ages on speleothems. Our outside temperatures agreed with meteorological ones. Our inside temperatures were over 1°C lower. To allow for this, a mean of ‘empirical’, ‘linear’ and ‘parabolic’ epimerisation calculations suggests that ratios from molluscs inside the caves should be multiplied by over 1.1 for comparison with outside ratios. This raises Bowen et al.'s ‘Pennard’ stage ratios from inside Minchin (and Bacon) Hole up towards the ‘Unnamed’ stage ratios outside, and suggests that the Unnamed sites are also from Oxygen Isotope Substage 5e, as proposed by Proctor and Smart. The same conclusion is reached more strongly by comparisons with the ratios and temperatures inside Belle Hougue to the south, and at Eemian (assumed 5e) sites in The Netherlands, Germany and Denmark to the east. The Pennard ratios from outside sites may provide further evidence for global sea stands close to the present level later in Oxygen Isotope Stage 5.

Development of high temperature transport technology for LiCl-KCl eutectic salt in pyroprocessing

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

Lee, Sung Ho; Lee, Hansoo; Kim, In Tae

The development of high-temperature transport technologies for molten salt is a prerequisite and a key issue in the industrialization of pyro-reprocessing for advanced fuel cycle scenarios. The solution of a molten salt centrifugal pump was discarded because of the high corrosion power of a high temperature molten salt, so the suction pump solution was selected. An apparatus for salt transport experiments by suction was designed and tested using LiC-KCl eutectic salt. The experimental results of lab-scale molten salt transport by suction showed a 99.5% transport rate (ratio of transported salt to total salt) under a vacuum range of 100 mtorrmore » - 10 torr at 500 Celsius degrees. The suction system has been integrated to the PRIDE (pyroprocessing integrated inactive demonstration) facility that is a demonstrator using non-irradiated materials (natural uranium and surrogate materials). The performance of the suction pump for the transport of molten salts has been confirmed.« less

D:L-Amino Acid Modeling Reveals Fast Microbial Turnover of Days to Months in the Subsurface Hydrothermal Sediment of Guaymas Basin.

PubMed

Møller, Mikkel H; Glombitza, Clemens; Lever, Mark A; Deng, Longhui; Morono, Yuki; Inagaki, Fumio; Doll, Mechthild; Su, Chin-Chia; Lomstein, Bente A

2018-01-01

We investigated the impact of temperature on the microbial turnover of organic matter (OM) in a hydrothermal vent system in Guaymas Basin, by calculating microbial bio- and necromass turnover times based on the culture-independent D:L-amino acid model. Sediments were recovered from two stations near hydrothermal mounds (<74°C) and from one cold station (<9°C). Cell abundance at the two hydrothermal stations dropped from 10 8 to 10 6 cells cm -3 within ∼5 m of sediment depth resulting in a 100-fold lower cell number at this depth than at the cold site where numbers remained constant at 10 8 cells cm -3 throughout the recovered sediment. There were strong indications that the drop in cell abundance was controlled by decreasing OM quality. The quality of the sedimentary OM was determined by the diagenetic indicators %T AA C (percentage of total organic carbon present as amino acid carbon), %T AA N (percentage of total nitrogen present as amino acid nitrogen), aspartic acid:β-alanine ratios, and glutamic acid:γ-amino butyric acid ratios. All parameters indicated that the OM became progressively degraded with increasing sediment depth, and the OM in the hydrothermal sediment was more degraded than in the uniformly cold sediment. Nonetheless, the small community of microorganisms in the hydrothermal sediment demonstrated short turnover times. The modeled turnover times of microbial bio- and necromass in the hydrothermal sediments were notably faster (biomass: days to months; necromass: up to a few hundred years) than in the cold sediments (biomass: tens of years; necromass: thousands of years), suggesting that temperature has a significant influence on the microbial turnover rates. We suggest that short biomass turnover times are necessary for maintance of essential cell funtions and to overcome potential damage caused by the increased temperature.The reduced OM quality at the hyrothemal sites might thus only allow for a small population size of microorganisms.

No evidence of temperature-dependent sex determination or sex-biased embryo mortality in the chicken.

PubMed

Collins, K E; Jordan, B J; McLendon, B L; Navara, K J; Beckstead, R B; Wilson, J L

2013-12-01

Skewing the sex ratio at hatch in commercial poultry would be economically beneficial to the poultry industry. The existence of temperature-dependent sex determination is uncertain in birds. This experiment investigated if incubation temperatures skew sex ratios of commercial broilers. Three incubators were each set at a hot (38.3°C), standard (37.5°C), or cool (36.7°C) single-stage incubation temperature one time over 3 trials to eliminate incubator effect as a Latin square design. Sex ratios of hatched chicks and dead embryos were monitored. In one trial, embryo weights were evaluated. The percentages of male hatched chicks did not differ based on incubation temperature (P = 0.4486; 49.5% in the hot treatment, 51.4% at standard temperature, and 49.8% in the cool treatment). The percent hatch of eggs set was lower in the hot treatment (83.6%) than the standard (93.5%) and cool (91.6%) treatments (P < 0.0001) with greater late embryonic mortality in the hot treatment (P < 0.0001); however, the sex ratio of dead embryos did not differ among treatments (P = 0.9863). Pooled data of embryo mortality found no sex-biased embryo mortality with a female/male sex ratio of 1.22:1 (χ(2) = 1.27; P = 0.2596). Embryos from the hot treatment were heavier than those from the standard treatment by d 14 of incubation and were heavier than the embryos from the cool treatment by d 9 of incubation (P < 0.0001). These data indicate that incubation temperature affects embryonic mortality and embryonic growth rate, but it does not affect the sex ratio of broiler chickens. Additionally, no evidence was found for sex-biased embryo mortality in commercial broilers even at the incubation temperatures of this study.

Automated determination of the stable carbon isotopic composition (δ13C) of total dissolved inorganic carbon (DIC) and total nonpurgeable dissolved organic carbon (DOC) in aqueous samples: RSIL lab codes 1851 and 1852

USGS Publications Warehouse

Révész, Kinga M.; Doctor, Daniel H.

2014-01-01

The purposes of the Reston Stable Isotope Laboratory (RSIL) lab codes 1851 and 1852 are to determine the total carbon mass and the ratio of the stable isotopes of carbon (δ13C) for total dissolved inorganic carbon (DIC, lab code 1851) and total nonpurgeable dissolved organic carbon (DOC, lab code 1852) in aqueous samples. The analysis procedure is automated according to a method that utilizes a total carbon analyzer as a peripheral sample preparation device for analysis of carbon dioxide (CO2) gas by a continuous-flow isotope ratio mass spectrometer (CF-IRMS). The carbon analyzer produces CO2 and determines the carbon mass in parts per million (ppm) of DIC and DOC in each sample separately, and the CF-IRMS determines the carbon isotope ratio of the produced CO2. This configuration provides a fully automated analysis of total carbon mass and δ13C with no operator intervention, additional sample preparation, or other manual analysis. To determine the DIC, the carbon analyzer transfers a specified sample volume to a heated (70 °C) reaction vessel with a preprogrammed volume of 10% phosphoric acid (H3PO4), which allows the carbonate and bicarbonate species in the sample to dissociate to CO2. The CO2 from the reacted sample is subsequently purged with a flow of helium gas that sweeps the CO2 through an infrared CO2 detector and quantifies the CO2. The CO2 is then carried through a high-temperature (650 °C) scrubber reactor, a series of water traps, and ultimately to the inlet of the mass spectrometer. For the analysis of total dissolved organic carbon, the carbon analyzer performs a second step on the sample in the heated reaction vessel during which a preprogrammed volume of sodium persulfate (Na2S2O8) is added, and the hydroxyl radicals oxidize the organics to CO2. Samples containing 2 ppm to 30,000 ppm of carbon are analyzed. The precision of the carbon isotope analysis is within 0.3 per mill for DIC, and within 0.5 per mill for DOC.

Treatments for reducing total vicine in Egyptian faba bean (Giza 2 variety).

PubMed

Abd Allah, M A; Foda, Y H; Abu Salem, F M; Abd Allah, Z S

1988-01-01

The response of faba bean 'Vicia faba' (Giza 2 variety) towards soaking conditions differed greatly since the absorbed quantities of water (either by the whole or the decorticated forms) are a function of their chemical constituents. On the other hand, 28.45% of the total vicine (vicine & convicine) present in the whole faba bean samples was extracted after soaking for 72 h at room temperature. Subsequently, other soaking mediums, i.e., 0.5% sodium carbonate and/or 1% acetic acid were used in an attempt to increase the level of vicine elimination. Percentage removal of total vicine in whole faba bean was higher in the acidic (61.31%) than the alkaline (38.40%) medium under the conditions tested, i.e., at room temperature for 72 hours. The rates of vicine + convicine elimination in decorticated faba bean for the acidic acid and alkaline soaking media were 78.46 and 79.13%, respectively. The solubility ratio of total vicine relative to soaking solutions (H2O:Na2CO3:Acetic acid) was 1:1.35:2.16 in the whole broad bean and 1:2.41:2.39 in the decorticated samples. The residual amounts of total vicine (78.33% and 77.27%) present after stewing under normal and under pressure cooking conditions could be expected to be decreased to 30.33% for the former and 29.92% for the later after 72 h of soaking. Regression analysis was used to estimate the theoretical zero point of vicine elimination from faba bean through soaking in 1% acetic acid.

Effects of dormancy progression and low-temperature response on changes in the sorbitol concentration in xylem sap of Japanese pear during winter season.

PubMed

Ito, Akiko; Sugiura, Toshihiko; Sakamoto, Daisuke; Moriguchi, Takaya

2013-04-01

In order to elucidate which physiological event(s) are involved in the seasonal changes of carbohydrate dynamics during winter, we examined the effects of different low temperatures on the carbohydrate concentrations of Japanese pear (Pyrus pyrifolia (Burm.) Nakai). For four winter seasons, large increases in the sorbitol concentration of shoot xylem sap occurred during mid- to late December, possibly due to the endodormancy completion and low-temperature responses. When trees were kept at 15 °C from 3 November to 3 December in order to postpone the initiation and completion of chilling accumulation that would break endodormancy, sorbitol accumulation in xylem sap was always higher from trees with sufficient chilling accumulation than from trees that received insufficient chilling. However, an additional increase in xylem sap sorbitol occurred around late December in trees regardless of whether their chilling accumulation naturally progressed or was postponed. To examine different temperature effects more closely, we compared the carbohydrate concentrations of trees subjected to either 6 or 0 °C treatment. The sorbitol concentration in xylem sap tremendously increased at 0 °C treatment compared with 6 °C treatment. However, an additional increase in xylem sap sorbitol occurred at both the temperatures when sufficient chilling accumulated with a peak coinciding with the peak expression in shoots of the sorbitol transporter gene (PpSOT2). Interestingly, the total carbohydrate concentration of shoots tremendously increased with exposure to 0 °C compared with exposure to 6 °C, but was not affected by the amount of accumulated chilling. Instead, as chilling accumulated the ratio of sorbitol to total soluble sugars in shoots increased. We presumed that carbohydrates in the shoot tissues may be converted to sorbitol and loaded into the xylem sap so that the sorbitol accumulation patterns were synchronized with the progression of dormancy, whereas the total carbohydrate transported into shoots from other storage organs may be related to freezing tolerance acquisition independent of dormancy progression. We thus propose that there are different effects of dormancy progression and low-temperature responses on carbohydrate dynamics in Japanese pear.

Perspectives on dilution jet mixing

NASA Technical Reports Server (NTRS)

Holdeman, J. D.

1986-01-01

A microcomputer code which displays 3-D oblique and 2-D plots of the temperature distribution downstream of jets mixing with a confined crossflow has been used to investigate the effects of varying the several independent flow and geometric parameters on the mixing. Temperature profiles calculated with this empirical model are presented to show the effects of orifice size and spacing, momentum flux ratio, density ratio, variable temperature mainstream, flow area convergence, orifice aspect ratio, and opposed and axially staged rows of jets.

Sexual and somatic development of wood frog tadpoles along a thermal gradient.

PubMed

Lambert, Max R; Smylie, Meredith S; Roman, Amber J; Freidenburg, L Kealoha; Skelly, David K

2018-02-01

All amphibian species are known to have genetic sex determination. However, a variety of environmental conditions can moderate sexual differentiation, in some cases leading to sex reversal and skewed sex ratios. While there has been a recent focus on chemically-induced sex reversal in amphibians, temperature can also influence sexual differentiation. Building upon a classic 1929 study by Emil Witschi, we assessed temperature-mediated sex reversal. Witschi found that the wood frog sex ratio is 100% male at a high temperature (32°C) compared to a 50:50 sex ratio at 20°C. This pattern is consistent with multiple models of environmentally mediated sexual differentiation in vertebrates. To better understand thermally mediated sex reversal, we raised wood frogs at temperature increments of ∼1°C between 19 and 34°C. Mirroring earlier findings, wood frog metamorph sex ratios are indistinguishable from 50:50 at the lowest temperature and entirely male at the highest temperatures. In between, sex ratios become increasingly male-dominated as temperatures increase, implying a steadily increasing tendency toward female-to-male sex reversal in warmer environments. There was no evidence of a threshold temperature effect on reversal patterns. We also show that, compared to males, females metamorphose larger and later in cooler conditions but earlier and smaller under warmer conditions. While the ecological relevance in this species is unknown, these results conform to the Charnov-Bull model of sex determination (in which female-to-male sex reversal can increase fitness to genetic females at higher temperatures), suggesting the system would reward further study. © 2018 Wiley Periodicals, Inc.

Thermodynamic analysis on heavy metals partitioning impacted by moisture during the MSW incineration

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

Zhang Yanguo; Li Qinghai; Jia Jinyan

2012-12-15

Highlights: Black-Right-Pointing-Pointer Partitioning of HMs affected by moisture was investigated by thermodynamic analysis. Black-Right-Pointing-Pointer Increase in moisture and in temperature was opposite impact on HMs contribution. Black-Right-Pointing-Pointer The extent of temperature decreased by increase in moisture determines the impact. - Abstract: A thermodynamic calculation was carried out to predict the behavior and speciation of heavy metals (HMs), Pb, Zn, Cu, and Cd, during municipal solid waste (MSW) incineration with the different moisture levels. The calculation was based on the minimization of the total Gibbs free energy of the multi-components and multi-phases closed system reaching chemical equilibrium. The calculation also indicatedmore » the reaction directions and tendencies of HMs components. The impacts of chlorine additives (No PVC, 1%PVC, and 5%PVC) and moisture on the behavior of HMs were investigated at different temperature levels in the system (750 Degree-Sign C, 950 Degree-Sign C, and 1150 Degree-Sign C). Furthermore, because the incineration temperature falls down with the increase in moisture in waste, the co-influence of moisture and temperature in combusting MSW on the HMs was also studied with the given chlorine (as 1%PVC + 0.5%NaCl). The results showed that in the non-chlorine system, the impact of the moisture on Pb, Zn, and Cu was not significant, and the ratio of compound transformation was less than 10%, except the Cd compounds at 950 Degree-Sign C and 1150 Degree-Sign C. In the system with low chlorine (as 1%PVC) at constant temperature, the chlorides of HMs (Cd, Pb, Zn, and Cu) transferred to oxides, and when the content of chlorine rose up (as 5%PVC), the ratio of the chlorides of HMs (Cd, Pb, Zn, and Cu) transferring to oxides fell down noticeably. When the moisture varied together with the temperature, the Zn and Cu compounds transferred from chlorides to oxides with increase in moisture as well as decrease in temperature. At the temperature of 700-1000 Degree-Sign C, the impact of temperature on Pb and Cd was little and the moisture was the main factor; while at the temperature of 1000-1200 Degree-Sign C, the impact of increase in moisture and decrease in temperature on Pb and Cd was almost equal and reversed.« less

Interactive effect of warming, nitrogen and phosphorus limitation on phytoplankton cell size

PubMed Central

Peter, Kalista Higini; Sommer, Ulrich

2015-01-01

Cell size is one of the ecologically most important traits of phytoplankton. The cell size variation is frequently related to temperature and nutrient limitation. In order to disentangle the role of both factors, an experiment was conducted to determine the possible interactions of these factors. Baltic Sea water containing the natural plankton community was used. We performed a factorial combined experiment of temperature, type of nutrient limitation (N vs. P), and strength of nutrient limitation. The type of nutrient limitation was manipulated by altering the N:P ratio of the medium (balanced, N and P limitation) and strength by the dilution rate (0% and 50%) of the semicontinuous cultures. The negative effect of temperature on cell size was strongest under N limitation, intermediate under P limitation, and weakest when N and P were supplied at balanced ratios. However, temperature also influenced the intensity of nutrient imitation, because at higher temperature there was a tendency for dissolved nutrient concentrations to be lower, while the C:N or C:P ratio being higher…higher at identical dilution rates and medium composition. Analyzing the response of cell size to C:N ratios (as index of N limitation) and C:P ratios (as index of P limitation) indicated a clear dominance of the nutrient effect over the direct temperature effect, although the temperature effect was also significant. PMID:25798219

Fundamental Interactions in Gasoline Compression Ignition Engines with Fuel Stratification

NASA Astrophysics Data System (ADS)

Wolk, Benjamin Matthew

Transportation accounted for 28% of the total U.S. energy demand in 2011, with 93% of U.S. transportation energy coming from petroleum. The large impact of the transportation sector on global climate change necessitates more-efficient, cleaner-burning internal combustion engine operating strategies. One such strategy that has received substantial research attention in the last decade is Homogeneous Charge Compression Ignition (HCCI). Although the efficiency and emissions benefits of HCCI are well established, practical limits on the operating range of HCCI engines have inhibited their application in consumer vehicles. One such limit is at high load, where the pressure rise rate in the combustion chamber becomes excessively large. Fuel stratification is a potential strategy for reducing the maximum pressure rise rate in HCCI engines. The aim is to introduce reactivity gradients through fuel stratification to promote sequential auto-ignition rather than a bulk-ignition, as in the homogeneous case. A gasoline-fueled compression ignition engine with fuel stratification is termed a Gasoline Compression Ignition (GCI) engine. Although a reasonable amount of experimental research has been performed for fuel stratification in GCI engines, a clear understanding of how the fundamental in-cylinder processes of fuel spray evaporation, mixing, and heat release contribute to the observed phenomena is lacking. Of particular interest is gasoline's pressure sensitive low-temperature chemistry and how it impacts the sequential auto-ignition of the stratified charge. In order to computationally study GCI with fuel stratification using three-dimensional computational fluid dynamics (CFD) and chemical kinetics, two reduced mechanisms have been developed. The reduced mechanisms were developed from a large, detailed mechanism with about 1400 species for a 4-component gasoline surrogate. The two versions of the reduced mechanism developed in this work are: (1) a 96-species version and (2) a 98-species version including nitric oxide formation reactions. Development of reduced mechanisms is necessary because the detailed mechanism is computationally prohibitive in three-dimensional CFD and chemical kinetics simulations. Simulations of Partial Fuel Stratification (PFS), a GCI strategy, have been performed using CONVERGE with the 96-species reduced mechanism developed in this work for a 4-component gasoline surrogate. Comparison is made to experimental data from the Sandia HCCI/GCI engine at a compression ratio 14:1 at intake pressures of 1 bar and 2 bar. Analysis of the heat release and temperature in the different equivalence ratio regions reveals that sequential auto-ignition of the stratified charge occurs in order of increasing equivalence ratio for 1 bar intake pressure and in order of decreasing equivalence ratio for 2 bar intake pressure. Increased low- and intermediate-temperature heat release with increasing equivalence ratio at 2 bar intake pressure compensates for decreased temperatures in higher-equivalence ratio regions due to evaporative cooling from the liquid fuel spray and decreased compression heating from lower values of the ratio of specific heats. The presence of low- and intermediate-temperature heat release at 2 bar intake pressure alters the temperature distribution of the mixture stratification before hot-ignition, promoting the desired sequential auto-ignition. At 1 bar intake pressure, the sequential auto-ignition occurs in the reverse order compared to 2 bar intake pressure and too fast for useful reduction of the maximum pressure rise rate compared to HCCI. Additionally, the premixed portion of the charge auto-ignites before the highest-equivalence ratio regions. Conversely, at 2 bar intake pressure, the premixed portion of the charge auto-ignites last, after the higher-equivalence ratio regions. More importantly, the sequential auto-ignition occurs over a longer time period for 2 bar intake pressure than at 1 bar intake pressure such that a sizable reduction in the maximum pressure rise rate compared to HCCI can be achieved.

Temperature Measurements in the Solar Transition Region Using N III Line Intensity Ratios

NASA Technical Reports Server (NTRS)

Doron, R.; Doschek, G. A.; Laming, J. M.; Feldman, U.; Bhatia, A. K.

2003-01-01

UV emission from B-like N and O ions a rather rare opportunity for recording spectral lines in a narrow wavelength range that can potentially be used to derive temperatures relevant to the solar transition region. In these ions, the line intensity ratios of the type (2s2p(sup 2) - 2p(sup 3)) / (2s(sup 2)2p - 2s2p(sup 2)) are very sensitive to the electron temperature. Additionally, the lines involving the ratios fall within a range of only - 12 A; in N III the lines fall in the 980 - 992 A range and in O IV in the 780 - 791 A range. In this work, we explore the use of these atomic systems, primarily in N III, for temperature diagnostics of the transition region by analyzing UV spectra obtained by the Solar Ultraviolet Measurements of Emitted Radiation (SUMER) spectrometer flown on the Solar and Heliospheric Observatory (SOHO). The N III temperature-sensitive line ratios are measured in more than 60 observations. Most of the measured ratios correspond to temperatures in the range 5.7x10(exp 4) - 6.7x10(exp 4) K. This range is considerably lower than the calculated temperature of maximum abundance of N III, which is approx. 7.6x10(exp 4) K. Detailed analysis of the spectra further indicates that the measured ratios are probably somewhat overestimated due to resonant scattering effects in the 2s(sup 2)2p - 2s2p(sup 2) lines and small blends in the 2s2p(sup 2) - 2p3 lines. Actual lower ratios would only increase the disagreement between the ionization balance calculations and present temperature measurements based on a collisional excitation model. In the case of the O IV spectra, we determined that due to the close proximity in wavelength of the weak line (2s2p(sup 2)-2p3 transitions) to a strong Ne VIII line, sufficiently accurate ratio measurements cannot be obtained. Subject headings: atomic data --- atomic processes --- Sun: transition region --- Sun: U V radiation --- techniques: spectroscopic

Temperature and pressure influence on maximum rates of pressure rise during explosions of propane-air mixtures in a spherical vessel.

PubMed

Razus, D; Brinzea, V; Mitu, M; Movileanu, C; Oancea, D

2011-06-15

The maximum rates of pressure rise during closed vessel explosions of propane-air mixtures are reported, for systems with various initial concentrations, pressures and temperatures ([C(3)H(8)]=2.50-6.20 vol.%, p(0)=0.3-1.3 bar; T(0)=298-423 K). Experiments were performed in a spherical vessel (Φ=10 cm) with central ignition. The deflagration (severity) index K(G), calculated from experimental values of maximum rates of pressure rise is examined against the adiabatic deflagration index, K(G, ad), computed from normal burning velocities and peak explosion pressures. At constant temperature and fuel/oxygen ratio, both the maximum rates of pressure rise and the deflagration indices are linear functions of total initial pressure, as reported for other fuel-air mixtures. At constant initial pressure and composition, the maximum rates of pressure rise and deflagration indices are slightly influenced by the initial temperature; some influence of the initial temperature on maximum rates of pressure rise is observed only for propane-air mixtures far from stoichiometric composition. The differentiated temperature influence on the normal burning velocities and the peak explosion pressures might explain this behaviour. Copyright © 2011 Elsevier B.V. All rights reserved.

[Radiometers performance attenuation and data correction in long-term observation of total radiation and photosynthetically active radiation in typical forest ecosystems in China].

PubMed

Zhu, Zhi-Lin; Sun, Xiao-Min; Yu, Gui-Rui; Wen, Xue-Fa; Zhang, Yi-Ping; Han, Shi-Jie; Yan, Jun-Hua; Wang, Hui-Min

2011-11-01

Based on the total radiation and photosynthetically active radiation (PAR) observations with net radiometer (CNR1) and quantum sensor (Li-190SB) in 4 ChinaFLUX forest sites (Changbaishan, Qianyanzhou, Dinghushan, and Xishuangbanna) in 2003-2008, this paper analyzed the uncertainties and the radiometers performance changes in long-term and continuous field observation. The results showed that the 98% accuracy of the total radiation measured with CNR1 (Q(cNR1)) could satisfy the technical criterion for the sites except Xishuangbanna where the Q(CNR1) was averagely about 7% lower than Q(CM11), the radiation measured with high accuracy pyranometer CM11. For most sites, though the temperature had definite effects on the performance of CNR1, the effects were still within the allowable range of the accuracy of the instrument. Besides temperature, the seasonal fog often occurred in tropical rain forests in Xishuangbanna also had effects on the performance of CNR1. Based on the long-term variations of PAR, especially its ratio to total radiation in the 4 sites, it was found that quantum sensor (Li-190SB) had obvious performance attenuation, with the mean annual attenuation rate being about 4%. To correct the observation error caused by Li-190SB, an attempt was made to give a post-correction of the PAR observations, which could basically eliminate the quantum sensor's performance attenuation due to long-term field measurement.

High temperature seal for joining ceramics and metal alloys

DOEpatents

Maiya, P.S.; Picciolo, J.J.; Emerson, J.E.; Dusek, J.T.; Balachandran, U.

1998-03-10

For a combination of a membrane of SrFeCo{sub 0.5}O{sub x} and an Inconel alloy, a high-temperature seal is formed between the membrane and the alloy. The seal is interposed between the alloy and the membrane, and is a fritted compound of Sr oxide and boric oxide and a fritted compound of Sr, Fe and Co oxides. The fritted compound of SrFeCo{sub 0.50}O{sub x} is present in the range of from about 30 to 70 percent by weight of the total sealant material and the fritted compound of Sr oxide and boric oxide has a mole ratio of 2 moles of the Sr oxide for each mole of boric oxide. A method of sealing a ceramic to an Inconel metal alloy is also disclosed. 3 figs.

High temperature seal for joining ceramics and metal alloys

DOEpatents

Maiya, P. Subraya; Picciolo, John J.; Emerson, James E.; Dusek, Joseph T.; Balachandran, Uthamalingam

1998-01-01

For a combination of a membrane of SrFeCo.sub.0.5 O.sub.x and an Inconel alloy, a high-temperature seal is formed between the membrane and the alloy. The seal is interposed between the alloy and the membrane, and is a fritted compound of Sr oxide and boric oxide and a fritted compound of Sr, Fe and Co oxides. The fritted compound of SrFeCo.sub.0.50 O.sub.x is present in the range of from about 30 to 70 percent by weight of the total sealant material and the fritted compound of Sr oxide and boric oxide has a mole ratio of 2 moles of the Sr oxide for each mole of boric oxide. A method of sealing a ceramic to an Inconel metal alloy is also disclosed.

Size tunability and optical properties of CdSe quantum dots for various growth conditions

NASA Astrophysics Data System (ADS)

Ko, Eun Yee; Lee, Joo In; Jeon, Ju-Won; Lee, In Hwan; Shin, Yong Hyeon; Han, Il Ki

2013-01-01

We report the optical properties of CdSe quantum dots (QDs) synthesized under various growth conditions, such as growth temperature, growth time, ligand ratio, and Cd:Se ratio of the precursors. As the growth temperature and time was increased, the peaks of the photoluminescence (PL) spectra were a red shifted, indicating that the size of QDs increased. Different ligand ratios and Cd:Se ratios of the precursors played important roles in determining the QDs size. From the PL spectra and the transmission electron microscopy image, the size distribution, as well as the size of CdSe QDs, could be controlled by using the growth conditions. The temperature-dependent PL of CdSe QDs dropped and dried on Si substrates was measured at temperatures from 15 K to 290 K. With increasing temperature, the red shift of the QDs was about 35 meV, which is noticeably smaller than that of bulk CdSe (˜100 meV). The influence of the temperature on the optical properties of colloidal CdSe QDs is important for an application to various devices.

Very short-lived bromomethanes measured by the CARIBIC observatory over the North Atlantic, Africa and Southeast Asia during 2009-2013

NASA Astrophysics Data System (ADS)

Wisher, A.; Oram, D. E.; Laube, J. C.; Mills, G. P.; van Velthoven, P.; Zahn, A.; Brenninkmeijer, C. A. M.

2014-04-01

Short-lived organic brominated compounds make up a significant part of the organic bromine budget in the atmosphere. Emissions of these compounds are highly variable and there are limited measurements, particularly in the extra-tropical upper troposphere/lower stratosphere and tropical troposphere. Measurements of five very short-lived bromomethanes (VSLB) were made in air samples collected on the CARIBIC project aircraft over three flight routes; Germany to Venezuela/Columbia during 2009-2011, Germany to South Africa during 2010 and 2011 and Germany to Thailand/Kuala Lumpur, Malaysia during 2012 and 2013. In the tropical troposphere, as the most important entrance region to the stratosphere, we observe a total mean organic bromine derived from these compounds across all flights at 10-12 km altitude of 3.4 ± 1.5 ppt. Individual mean tropical tropospheric mixing ratios across all flights were 0.43, 0.74, 0.14, 0.23 and 0.11 ppt for CHBr3, CH2Br2, CHBr2Cl, CHBrCl2 and CH2BrCl respectively. The highest levels of VSLB-derived bromine (4.20 ± 0.56 ppt) were observed in flights between Bangkok and Kuala Lumpur indicating that the South China Sea is an important source region for these compounds. Across all routes, CHBr3 and CH2Br2 accounted for 34% (4.7-71) and 48% (14-73) respectively of total bromine derived from the analysed VSLB in the tropical mid-upper troposphere totalling 82% (54-89). In samples collected between Germany and Venezuela/Columbia, we find decreasing mean mixing ratios with increasing potential temperature in the extra-tropics. Tropical mean mixing ratios are higher than extra-tropical values between 340-350 K indicating that rapid uplift is important in determining mixing ratios in the lower tropical tropopause layer in the West Atlantic tropics. O3 was used as a tracer for stratospherically influenced air and we detect rapidly decreasing mixing ratios for all VSLB above ∼100 ppb O3 corresponding to the extra-tropical tropopause layer.

Very short-lived bromomethanes measured by the CARIBIC observatory over the North Atlantic, Africa and South-East Asia during 2009-2013

NASA Astrophysics Data System (ADS)

Wisher, A.; Oram, D. E.; Laube, J. C.; Mills, G. P.; van Velthoven, P.; Zahn, A.; Brenninkmeijer, C. A. M.

2013-11-01

Short-lived organic brominated compounds make up a significant part (~20%) of the organic bromine budget in the atmosphere. Emissions of these compounds are highly variable and there are limited measurements, particularly in the extra-tropical upper troposphere/lower stratosphere and tropical troposphere. Measurements of five short-lived bromomethanes (VSLB) were made in air samples collected on the CARIBIC project aircraft over three flight routes; Germany to Venezuela/Columbia during 2009-2011, Germany to South Africa during 2010 and 2011 and Germany to Thailand/Kuala Lumpur, Malaysia during 2012 and 2013. In the tropical troposphere, as the most important entrance region to the stratosphere, we observe a total mean organic bromine derived from these compounds across all flights at 10-12 km altitude of 3.4 ± 1.5 ppt. Individual mean tropical tropospheric mixing ratios across all flights were 0.43, 0.74, 0.14, 0.23 and 0.11 ppt for CHBr3, CH2Br2, CHBr2Cl, CHBrCl2 and CH2BrCl respectively. The highest levels of VSLS-derived bromine (4.20 ± 0.56 ppt) were observed in flights between Bangkok and Kuala Lumpur indicating that the South China Sea is an important source region for these compounds. Across all routes, CHBr3 and CH2Br2 accounted for 34% (4.7-71) and 48% (14-73) respectively of total bromine derived from the analysed VSLB in the tropical mid-upper troposphere totalling 82% (54-89). In samples collected between Germany and Venezuela/Columbia, we find decreasing mean mixing ratios with increasing potential temperature in the extra-tropics. Tropical mean mixing ratios are higher than extra-tropical values between 340-350 K indicating that rapid uplift is important in determining mixing ratios in the lower tropical tropopause layer in the West Atlantic tropics. O3 was used as a tracer for stratospherically influenced air and we detect rapidly decreasing mixing ratios for all VSLB above ~100 ppb O3 corresponding to the extra-tropical tropopause layer.

13CO2/12CO2 isotope ratio analysis in human breath using a 2 μm diode laser

NASA Astrophysics Data System (ADS)

Sun, Mingguo; Cao, Zhensong; Liu, Kun; Wang, Guishi; Tan, Tu; Gao, Xiaoming; Chen, Weidong; Yinbo, Huang; Ruizhong, Rao

2015-04-01

The bacterium H. pylori is believed to cause peptic ulcer. H. pylori infection in the human stomach can be diagnosed through a CO2 isotope ratio measure in exhaled breath. A laser spectrometer based on a distributed-feedback semiconductor diode laser at 2 μm is developed to measure the changes of 13CO2/12CO2 isotope ratio in exhaled breath sample with the CO2 concentration of ~4%. It is characterized by a simplified optical layout, in which a single detector and associated electronics are used to probe CO2 spectrum. A new type multi-passes cell with 12 cm long base length , 29 m optical path length in total and 280 cm3 volume is used in this work. The temperature and pressure are well controlled at 301.15 K and 6.66 kPa with fluctuation amplitude of 25 mK and 6.7 Pa, respectively. The best 13δ precision of 0.06o was achieved by using wavelet denoising and Kalman filter. The application of denoising and Kalman filter not only improved the signal to noise ratio, but also shorten the system response time.

Comparison of High Aspect Ratio Cooling Channel Designs for a Rocket Combustion Chamber with Development of an Optimized Design

NASA Technical Reports Server (NTRS)

Wadel, Mary F.

1998-01-01

An analytical investigation on the effect of high aspect ratio (height/width) cooling channels, considering different coolant channel designs, on hot-gas-side wall temperature and coolant pressure drop for a liquid hydrogen cooled rocket combustion chamber, was performed. Coolant channel design elements considered were: length of combustion chamber in which high aspect ratio cooling was applied, number of coolant channels, and coolant channel shape. Seven coolant channel designs were investigated using a coupling of the Rocket Thermal Evaluation code and the Two-Dimensional Kinetics code. Initially, each coolant channel design was developed, without consideration for fabrication, to reduce the hot-gas-side wall temperature from a given conventional cooling channel baseline. These designs produced hot-gas-side wall temperature reductions up to 22 percent, with coolant pressure drop increases as low as 7.5 percent from the baseline. Fabrication constraints for milled channels were applied to the seven designs. These produced hot-gas-side wall temperature reductions of up to 20 percent, with coolant pressure drop increases as low as 2 percent. Using high aspect ratio cooling channels for the entire length of the combustion chamber had no additional benefit on hot-gas-side wall temperature over using high aspect ratio cooling channels only in the throat region, but increased coolant pressure drop 33 percent. Independent of coolant channel shape, high aspect ratio cooling was able to reduce the hot-gas-side wall temperature by at least 8 percent, with as low as a 2 percent increase in coolant pressure drop. ne design with the highest overall benefit to hot-gas-side wall temperature and minimal coolant pressure drop increase was the design which used bifurcated cooling channels and high aspect ratio cooling in the throat region. An optimized bifurcated high aspect ratio cooling channel design was developed which reduced the hot-gas-side wall temperature by 18 percent and reduced the coolant pressure drop by 4 percent. Reductions of coolant mass flow rate of up to 50 percent were possible before the hot-gas-side wall temperature reached that of the baseline. These mass flow rate reductions produced coolant pressure drops of up to 57 percent.

Geopolymer lightweight bricks manufactured from fly ash and foaming agent

NASA Astrophysics Data System (ADS)

Ibrahim, Wan Mastura Wan; Hussin, Kamarudin; Abdullah, Mohd Mustafa Al Bakri; Kadir, Aeslina Abdul

2017-04-01

This paper deals with the development of lightweight geopolymer bricks by using foaming agent and fly ash. The mix parameters analysed through a laboratory experiment with fix ratio of sodium silicate/sodium hydroxide solution mass ratio 2.5, fly ash/alkaline activator solution mass ratio 2.0, foaming agent/paste mass ratio 1:2 and molarity of sodium hydroxide solution used was 12M. Different curing temperature (Room Temperature, 60, 80) and foaming agent/water mass ratio (1:10 and 1:20) were studied. Compressive strength, density analysis, and water absorption has been investigated. The results show that the foamed geopolymer bricks with a lower foam/water mass ratio (1:10)and high curing temperature (80°C) leading to a better properties. Mixtures with a low density of around 1420 kg/m3 and a compressive strength of around 10 MPa were achieved.

Effect of ground corn cobs as a fiber source in total mixed ration on feed intake, milk yield and milk composition in tropical lactating crossbred Holstein cows.

PubMed

Wachirapakorn, Chalong; Pilachai, Krung; Wanapat, Metha; Pakdee, Pawadee; Cherdthong, Anusorn

2016-12-01

The aim of this study was to evaluate the effect of ground corn cobs (GCC) as a sole fiber source in total mixed ration (TMR) on feed intake, milk yield and milk composition in tropical lactating crossbred Holstein cows. Four multiparous crossbreds Holstein Friesian dairy cows with an initial body weight (BW) of 415.5 ± 26.20 kg were used in a 4 × 4 Latin square design. The dietary treatments of TMR contained a roughage-to-concentrate ratio of 40:60. The roughage source was used at different ratios of GCC to rice straw (RS) at 100:0, 82.5:17.5, 67.5:32.5, and 50:50 for TMR1 to TMR4, respectively. The results revealed significant improvements in intake of dry matter, protein, neutral detergent fiber (NDF) and metabolizable energy (ME) for TMR1 and TMR2 ( P  < 0.05), while the digestibility of nutrients was not altered by the treatments ( P  ≥ 0.05). Ground corn cobs was used for up to 100% of the total roughage without affecting milk production. Moreover, ruminal pH, temperature, ammonia-nitrogen (NH 3 -N) and volatile fatty acid (VFA) concentrations were not impacted by the treatments ( P  > 0.05). However, milk yield was significantly different among the GCC:RS ratios ( P  < 0.05) and was the highest in TMR1 and TMR2 (13.1 kg/d), while the milk compositions were not changed ( P  > 0.05). The results imply that using GCC as a whole roughage source significantly improved nutrients intake and milk yield in dairy cows raised in tropical areas.

Patterns and drivers of soil microbial communities in temperate grasslands on the Mongolian plateau

NASA Astrophysics Data System (ADS)

Yang, Y.; Hu, H.; Hao, B.; Liu, Y.; Chen, Y.; Ma, W.

2016-12-01

Soil microorganisms play key roles in regulating many important ecosystem processes. However, our understanding of the patterns and drivers of soil microbial communities at the regional scale remains limited. In this study, on the basis of phospholipid fatty acid (PLFA) analysis, we investigated large-scale patterns and drivers of soil microbial communities using data from 78 sites between two depths (0-10 cm and 10-20 cm) within three major grassland types (desert steppe, typical steppe, and meadow steppe) on the Mongolian Plateau. Our findings demonstrated that, at the regional scale, the total soil microbial biomass, fungal biomass, bacterial biomass, and actinomycete biomass in Inner Mongolian temperate grasslands were all positively associated with mean annual precipitation (MAP), soil organic carbon (SOC), soil total nitrogen (TN), C:N ratio, plant aboveground biomass (AGB), and plant species richness (SR), but negatively correlated with mean annual temperature (MAT), soil bulk density (BD), and soil pH in both depths, except actinomycete biomass with MAP and BD in 10-20 cm. A stepwise regression analysis revealed that soil microbial community variations in Inner Mongolian temperate grasslands were mainly explained by C : N ratio in 0-10 cm, but by SR (total soil microbial biomass, fungal biomass, and actinomycete biomass) and MAT (bacterial biomass) in 10-20 cm. Our findings strongly indicate that the dominant drivers of spatial variations in soil microbial communities between 0-10 cm and 10-20 cm in the Inner Mongolia grasslands are significantly different, with edaphic factors (e.g., C: N ratio) in 0-10 cm but climatic (e.g, MAT) and/or biotic (e.g, SR) in 10-20 cm.

Heat treatment of human esophageal tissues: Effect on esophageal cancer detection using oxygenated hemoglobin diffuse reflectance ratio

NASA Astrophysics Data System (ADS)

Zhao, Q. L.; Guo, Z. Y.; Si, J. L.; Wei, H. J.; Yang, H. Q.; Wu, G. Y.; Xie, S. S.; Guo, X.; Zhong, H. Q.; Li, L. Q.; Li, X. Y.

2011-03-01

The main objective of the present work is to study the influence of heat treatment on the esophageal cancer detection using the diffuse reflectance (DR) spectral intensity ratio R540/R575 of oxygenated hemoglobin (HbO2) absorption bands to distinguish the epithelial tissues of normal human esophagus and moderately differentiated esophageal squamous cell carcinoma (ESCC) at different heat treatment temperature of 20, 37, 42, 50, and 60°C, respectively. The DR spectra for the epithelial tissues of the normal esophagus and ESCC in vitro at different heat-treatment temperature in the wavelength range 400-650 nm were measured with a commercial optical fiber spectrometer. The results indicate that the average DR spectral intensity overall enhancement with concomitant increase of heat-treatment temperature for the epithelial tissues of normal esophagus and ESCC, but the average DR spectral intensity for the normal esophageal epithelial tissues is relatively higher than that for ESCC epithelial tissues at the same heat-treatment temperature. The mean R540/R575 ratios of ESCC epithelial tissues were always lower than that of normal esophageal epithelial tissues at the same temperature, and the mean R540/R575 ratios of the epithelial tissues of the normal esophagus and ESCC were decreasing with the increase of different heat-treatment temperatures. The differences in the mean R540/R575 ratios between the epithelial tissues of normal esophagus and ESCC were 13.33, 13.59, 11.76, and 11.11% at different heat-treatment temperature of 20, 37, 42, and 50°C, respectively. These results also indicate that the DR intensity ratio R540/R575 of the hemoglobin bands is a useful tool for discrimination between the epithelial tissues of normal esophagus and ESCC in the temperature range from room temperature to 50°C, but it was non-effective at 60°C or over 60°C.

Stratospheric N2O5, CH4, and N2O profiles from IR solar occultation spectra

NASA Technical Reports Server (NTRS)

Camy-Peyret, C.; Flaud, J.-M.; Perrin, A.; Rinsland, C. P.; Goldman, A.; Murcray, F. J.

1993-01-01

Stratospheric volume mixing ratio profiles of N2O5, CH4, and N2O have been retrieved from a set of 0.052/cm resolution (FWHM) solar occultation spectra recorded at sunrise during a balloon flight from Aire sur l'Adour, France (44 N latitude) on 12 October 1990. The N2O5 results have been derived from measurements of the integrated absorption by the 1246/cm band. Assuming a total intensity of 4.32 x 10 exp -17 cm/molecule/sq cm independent of temperature, the retrieved N2O5 volume mixing ratios in ppbv, interpolated to 2 km height spacings, are 1.64 +/- 0.49 at 37.5 km, 1.92 +/- 0.56 at 35.5 km, 2.06 +/- 0.47 at 33.5 km, 1.95 +/- 0.42 at 31.5 km, 1.60 +/- 0.33 at 29.5 km, 1.26 +/- 0.28 at 27.5 km, and 0.85 +/- 0.20 at 25.5 km. Error bars indicate the estimated 1-sigma uncertainty including the error in the total band intensity. The retrieved profiles are compared with previous measurements and photochemical model results.

Numerical Prediction of the Influence of Thrust Reverser on Aeroengine's Aerodynamic Stability

NASA Astrophysics Data System (ADS)

Zhiqiang, Wang; Xigang, Shen; Jun, Hu; Xiang, Gao; Liping, Liu

2017-11-01

A numerical method was developed to predict the aerodynamic stability of a high bypass ratio turbofan engine, at the landing stage of a large transport aircraft, when the thrust reverser was deployed. 3D CFD simulation and 2D aeroengine aerodynamic stability analysis code were performed in this work, the former is to achieve distortion coefficient for the analysis of engine stability. The 3D CFD simulation was divided into two steps, the single engine calculation and the integrated aircraft and engine calculation. Results of the CFD simulation show that with the decreasing of relative wind Mach number, the engine inlet will suffer more severe flow distortion. The total pressure and total temperature distortion coefficients at the inlet of the engines were obtained from the results of the numerical simulation. Then an aeroengine aerodynamic stability analysis program was used to quantitatively analyze the aerodynamic stability of the high bypass ratio turbofan engine. The results of the stability analysis show that the engine can work stably, when the reverser flow is re-ingested. But the anti-distortion ability of the booster is weaker than that of the fan and high pressure compressor. It is a weak link of engine stability.

Transgenerational plasticity mitigates the impact of global warming to offspring sex ratios.

PubMed

Donelson, Jennifer M; Munday, Philip L

2015-08-01

Global warming poses a threat to organisms with temperature-dependent sex determination because it can affect operational sex ratios. Using a multigenerational experiment with a marine fish, we provide the first evidence that parents developing from early life at elevated temperatures can adjust their offspring gender through nongenetic and nonbehavioural means. However, this adjustment was not possible when parents reproduced, but did not develop, at elevated temperatures. Complete restoration of the offspring sex ratio occurred when parents developed at 1.5 °C above the present-day average temperature for one generation. However, only partial improvement in the sex ratio occurred at 3.0 °C above average conditions, even after two generations, suggesting a limitation to transgenerational plasticity when developmental temperature is substantially increased. This study highlights the potential for transgenerational plasticity to ameliorate some impacts of climate change and that development from early life may be essential for expression of transgenerational plasticity in some traits. © 2015 John Wiley & Sons Ltd.

Meteorological variables affect fertility rate after intrauterine artificial insemination in sheep in a seasonal-dependent manner: a 7-year study.

PubMed

Palacios, C; Abecia, J A

2015-05-01

A total number of 48,088 artificial inseminations (AIs) have been controlled during seven consecutive years in 79 dairy sheep Spanish farms (41° N). Mean, maximum and minimum ambient temperatures (Ts), temperature amplitude (TA), mean relative humidity (RH), mean solar radiation (SR) and total rainfall of each insemination day and 15 days later were recorded. Temperature-humidity index (THI) and effective temperature (ET) have been calculated. A binary logistic regression model to estimate the risk of not getting pregnant compared to getting pregnant, through the odds ratio (OR), was performed. Successful winter inseminations were carried out under higher SR (P < 0.01) and summer inseminations under lower SR values (P < 0.05). Successful inseminations during the summer were performed under significantly lower maximum T (P < 0.01), while winter inseminations resulted in pregnancy when they were carried out under higher maximum (P < 0.05) and minimum Ts (P < 0.01). Up to five meteorological variables presented OR >1 (maximum T, ET and rainfall on AI day, and ET and rainfall on day 15), and two variables presented OR <1 (SR on AI day and maximum T on day 15). However, the effect of meteorological factors affected fertility in opposite ways, so T becomes a protective or risk factor on fertility depending on season. In conclusion, the percentage of pregnancy after AI in sheep is significantly affected by meteorological variables in a seasonal-dependent manner, so the parameters such as temperature reverse their effects in the hot or cold seasons. A forecast of the meteorological conditions could be a useful tool when AI dates are being scheduled.

Meteorological variables affect fertility rate after intrauterine artificial insemination in sheep in a seasonal-dependent manner: a 7-year study

NASA Astrophysics Data System (ADS)

Palacios, C.; Abecia, J. A.

2015-05-01

A total number of 48,088 artificial inseminations (AIs) have been controlled during seven consecutive years in 79 dairy sheep Spanish farms (41° N). Mean, maximum and minimum ambient temperatures ( Ts), temperature amplitude (TA), mean relative humidity (RH), mean solar radiation (SR) and total rainfall of each insemination day and 15 days later were recorded. Temperature-humidity index (THI) and effective temperature (ET) have been calculated. A binary logistic regression model to estimate the risk of not getting pregnant compared to getting pregnant, through the odds ratio (OR), was performed. Successful winter inseminations were carried out under higher SR ( P < 0.01) and summer inseminations under lower SR values ( P < 0.05). Successful inseminations during the summer were performed under significantly lower maximum T ( P < 0.01), while winter inseminations resulted in pregnancy when they were carried out under higher maximum ( P < 0.05) and minimum Ts ( P < 0.01). Up to five meteorological variables presented OR >1 (maximum T, ET and rainfall on AI day, and ET and rainfall on day 15), and two variables presented OR <1 (SR on AI day and maximum T on day 15). However, the effect of meteorological factors affected fertility in opposite ways, so T becomes a protective or risk factor on fertility depending on season. In conclusion, the percentage of pregnancy after AI in sheep is significantly affected by meteorological variables in a seasonal-dependent manner, so the parameters such as temperature reverse their effects in the hot or cold seasons. A forecast of the meteorological conditions could be a useful tool when AI dates are being scheduled.

Chemical properties and GMR improvement of specular spin valves with nano-oxide layers, formed in ambient mixed gases

NASA Astrophysics Data System (ADS)

Quang, H. D.; Hien, N. T.; Oh, S. K.; Sinh, N. H.; Yu, S. C.

2004-12-01

Specular spin valves (SVs) containing nano-oxide layers (NOLs) structured as substrate/seed/AF/P1/NOL/P2/Cu/F/NOL, have been fabricated. The NOLs were formed by natural oxidation in different ambient atmospheres of pure oxygen, oxygen/nitrogen and oxygen/argon gas mixtures. The fabrication conditions were optimized to enhance the magnetoresistance (MR) ratio, to suppress the interlayer coupling fields (Hf) between the free and pinned layers, to suppress the high interface density of the NOL, to ease the control of the NOL thickness and to form a smooth NOL/P2 interface for promoting specular electron scattering. The characteristics of our specular SVs are the MR ratio of 14.1%, the exchange bias field of 44-45 mT, and Hf weaker than 1.0 mT. The optimal conditions for oxidation time, total oxidation pressure and the annealing temperature were found to be 300 s, 0.14 Pa (oxygen/argon = 80/20) and 250°C, respectively. Also, the origin of thermal stability of MMn-based (M = Fe, Pt, Ir, etc) specular SVs has been explained in detail by chemical properties of NOL using secondary-ion mass spectroscopy and x-ray photoelectron spectroscopy depth profile analyses. Thermal stability turns out to be caused by a decrease in MR ratios at high temperatures (>250°C), which is a serious problem for device applications using the SV structure as a high density read head device.

Interlinkages between bacterial populations dynamics and the operational parameters in a moving bed membrane bioreactor treating urban sewage.

PubMed

Reboleiro-Rivas, P; Martín-Pascual, J; Morillo, J A; Juárez-Jiménez, B; Poyatos, J M; Rodelas, B; González-López, J

2016-01-01

Bacteria are key players in biological wastewater treatments (WWTs), thus a firm knowledge of the bacterial population dynamics is crucial to understand environmental/operational factors affecting the efficiency and stability of the biological depuration process. Unfortunately, little is known about the microbial ecology of the advanced biological WWTs combining suspended biomass (SB) and attached biofilms (AB). This study explored in depth the bacterial community structure and population dynamics in each biomass fraction from a pilot-scale moving bed membrane bioreactor (MBMBR) treating municipal sewage, by means of temperature-gradient gel electrophoresis (TGGE) and 454-pyrosequencing. Eight experimental phases were conducted, combining different carrier filling ratios, hydraulic retention times and concentrations of mixed liquor total suspended solids. The bacterial community, dominated by Proteobacteria (20.9-53.8%) and Actinobacteria (20.6-57.6%), was very similar in both biomass fractions and able to maintain its functional stability under all the operating conditions, ensuring a successful and steady depuration process. Multivariate statistical analysis demonstrated that solids concentration, carrier filling ratio, temperature and organic matter concentration in the influent were the significant factors explaining population dynamics. Bacterial diversity increased as carrier filling ratio increased (from 20% to 35%, v/v), and solids concentration was the main factor triggering the shifts of the community structure. These findings provide new insights on the influence of operational parameters on the biology of the innovative MBMBRs. Copyright © 2015 Elsevier Ltd. All rights reserved.

Mechanism of the surface runoff generation processes of a permafrost watershed in the Qinghai-Tibet plateau

NASA Astrophysics Data System (ADS)

Genxu, W.

2017-12-01

There is a lack of knowledge about how to quantify runoff generation and the hydrological processes operating in permafrost catchments on permafrost-dominant catchments. To understand the mechanism of runoff generation processes in permafrost catchments, a typical headwater catchment with continuous permafrost on the Tibetan Plateau was measured. A new approach is presented in this study to account for runoff processes on the spring thawing period and autumn freezing period, when runoff generation clearly differs from that of non-permafrost catchments. This approach introduces a soil temperature-based water saturation function and modifies the soil water storage curve with a soil temperature threshold. The results show that surface soil thawing induced saturation excess runoff and subsurface interflow account for approximately 66-86% and 14-34% of total spring runoff, respectively, and the soil temperature significantly affects the runoff generation pattern, the runoff composition and the runoff coefficient with the enlargement of the active layer. The suprapermafrost groundwater discharge decreases exponentially with active layer frozen processes during autumn runoff recession, whereas the ratio of groundwater discharge to total runoff and the direct surface runoff coefficient simultaneously increase. The bidirectional freezing of the active layer controls and changes the autumn runoff processes and runoff composition. The new approach could be used to further develop hydrological models of cold regions dominated by permafrost.

Role of hydration and water coordination in micellization of Pluronic block copolymers.

PubMed

Šturcová, Adriana; Schmidt, Pavel; Dybal, Jiří

2010-12-15

Raman, attenuated total reflectance FTIR, near-infrared spectroscopy, and DFT calculations have been used in a study of aqueous solutions of three tri-block copolymers poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) or PEO-PPO-PEO with commercial names Pluronic PE6200, PE6400 and F68. It is shown that the process of micellization as a response to increased temperature is reflected in the hydroxyl stretching region of infrared and Raman spectra, which contains information both about restructuring of water and changes of polymer chains in polymer/water aggregates. Raman spectra exhibit differences between individual Pluronics even at temperatures below the critical micellization temperature (CMT). According to the attenuated total reflection (ATR) FTIR spectra, the same five water coordination types defined by the number of donated/accepted hydrogen bonds are present in interacting water as in bulk water. It indicates that models considering mixed states of water with different hydrogen bonding environments provide appropriate descriptions of bound water both below and above the CMT. Above the CMT, aggregate hydration increases in the order PE6400 < PE6200 < F68, although that does not fully correspond to the EO/PO ratio, and points to the differences in microstructure of aggregates formed by each copolymer. This study relates nanoscale phenomena (hydrophobic and hydrophilic hydration) with the mesoscale phenomenon of micellization. Copyright © 2010 Elsevier Inc. All rights reserved.

Extratropical Influence of Sea Surface Temperature and Wind on Water Recycling Rate Over Oceans and Coastal Lands

NASA Technical Reports Server (NTRS)

Hu, Hua; Liu, W. Timothy

1999-01-01

Water vapor and precipitation are two important parameters confining the hydrological cycle in the atmosphere and over the ocean surface. In the extratropical areas, due to variations of midlatitude storm tracks and subtropical jetstreams, water vapor and precipitation have large variability. Recently, a concept of water recycling rate defined previously by Chahine et al. (GEWEX NEWS, August, 1997) has drawn increasing attention. The recycling rate of moisture is calculated as the ratio of precipitation to total precipitable water (its inverse is the water residence time). In this paper, using multi-sensor spacebased measurements we will study the role of sea surface temperature and ocean surface wind in determining the water recycling rate over oceans and coastal lands. Response of water recycling rate in midlatitudes to the El Nino event will also be discussed. Sea surface temperature data are derived from satellite observations from the Advanced Very High Resolution Radiometer (AVHRR) blended with in situ measurements, available for the period 1982-1998. Global sea surface wind observations are obtained from spaceborne scatterometers aboard on the European Remote-Sensing Satellite (ERS1 and 2), available for the period 1991-1998. Global total precipitable water provided by the NASA Water Vapor Project (NVAP) is available for the period 1988-1995. Global monthly mean precipitation provided by the Global Precipitation Climatology Project (GPCP) is available for the period 1987-1998.